Androgen receptor (AR) plays an important role in many kinds of cancers. However, the molecular mechanisms of AR in gastric cancer (GC) are poorly characterized. Here, we investigated the role of AR in GC cell migration, invasion and metastatic potential. Our data showed that AR expression was positively correlated with lymph node metastasis and late TNM stages. These findings were accompanied by activation of AKT and upregulation of matrix metalloproteinase 9 (MMP9). AR overexpression induced increases in GC cell migration, invasion and proliferation in vitro and in vivo. These effects were attenuated by inhibition of AKT, AR and MMP9. AR overexpression upregulated MMP9 protein levels, whereas this effect was counteracted by AR siRNA. Inhibition of AKT by siRNA or an inhibitor (MK-2206 2HC) decreased AR protein expression in both stably transfected and parental SGC-7901 cells. Luciferase reporter and chromatin immunoprecipitation assays demonstrated that AR bound to the AR-binding sites of the MMP9 promoter. In summary, AR overexpression induced by AKT phosphorylation upregulated MMP9 by binding to its promoter region to promote gastric carcinogenesis. The AKT/AR/MMP9 pathway plays an important role in GC metastasis and may be a novel therapeutic target for GC treatment.
The prolyl isomerase Pin1, which isomerizes the p-Ser/Thr-Pro peptide bonds and effects conformational and functional changes of the bound proteins, has been identified as a regulator of phosphorylation signaling in several diseases including cancer. The aim of this study is to determine the expression status of Pin1 in gastric cancer, its relationship between clinicopathologic features and patients' outcome. The mRNA levels of Pin1 in human normal and gastric cancer tissues were analyzed using the datasets from the publicly available Oncomine database ( www.oncomine.org ). Pin1 protein levels in human gastric cancer cells and tissues were analyzed by Western blot and immunohistochemistry staining, respectively. The Pin1 protein expression levels and its clinicopathologic correlations were investigated using tumor tissue microarray including 182 cases of human gastric cancer samples with survival information. Pin1 mRNA expression was found to be overexpressed in gastric cancer by using several datasets of Oncomine database analyzing. Pin1 protein expression is higher in 10 gastric cancer cell lines than that in normal gastric epithelial cell line GES-1. Pin1 positive expression was observed in 109 of 182 (59.9 %) gastric cancer samples and in 55 of 182 (30.2 %) normal gastric tissues (P < 0.001). Correlation analysis showed that high expression of Pin1 was significantly associated with pT (P = 0.017), pN (P = 0.043), TNM staging (P = 0.027), Lauren's classification (P < 0.001), as well as shorter overall survival in gastric cancer patients (29 mos vs. 47 mos. P = 0.048). Moreover, Pin1 expression, pT, and differentiation were independent prognostic factors of gastric cancer in Cox regression analysis. Pin1 is overexpressed in gastric cancer and correlates with clinicopathologic features, which might predict poor prognosis of gastric cancer patients.
Mounting evidence shows that microRNAs may be useful as prognostic biomarkers of gastric cancer. The aim of this meta-analysis was to summarize the predictive role of miR-21 for survival in patients with gastric cancer and to verify the association between expression of miR-21 and clinical characteristics.
A constitutive activation of protein kinase B (AKT) in a hyper-phosphorylated status at Ser473 is one of the hallmarks of anti-EGFR therapy-resistant colorectal cancer (CRC). The aim of this study was to examine the role of cytosolic phospholipase A2? (cPLA2?) on AKT phosphorylation at Ser473 and cell proliferation in CRC cells with mutation in phosphoinositide 3-kinase (PI3K). AKT phosphorylation at Ser473 was resistant to EGF stimulation in CRC cell lines of DLD-1 (PIK3CAE545K mutation) and HT-29 (PIK3CAP499T mutation). Over-expression of cPLA2? by stable transfection increased basal and EGF-stimulated AKT phosphorylation and proliferation in DLD-1 cells. In contrast, silencing of cPLA2? with siRNA or inhibition with Efipladib decreased basal and EGF-stimulated AKT phosphorylation and proliferation in HT-29. Treating animals transplanted with DLD-1 with Efipladib (10 mg/kg, i.p. daily) over 14 days reduced xenograft growth by >90% with a concomitant decrease in AKT phosphorylation. In human CRC tissue, cPLA2? expression and phosphorylation were increased in 63% (77/120) compared with adjacent normal mucosa determined by immunohistochemistry. We conclude that cPLA2? is required for sustaining AKT phosphorylation at Ser473 and cell proliferation in CRC cells with PI3K mutation, and may serve as a potential therapeutic target for treatment of CRC resistant to anti-EGFR therapy.
Oxaliplatin and the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA), also known as vorinostat, are potent antitumor agents. The aim of this study was to investigate the effect of SAHA on the antitumor efficacy of oxaliplatin in gastric cancer and the interaction between oxaliplatin and SAHA. Cell growth inhibition was evaluated using Cell Counting Kit?8 and colony formation assays. Xenografts established in nude mice were used to assess tumor growth in vivo. Western blot analysis was used to detect the expression of acetyl?histone H3, phosphorylated histone H2AX (?H2AX), B?cell lymphoma 2 (Bcl?2), cleaved caspase?3, cleaved poly (ADP?ribose) polymerase (PARP), phosphorylated- (p-)Src, Src, Akt and p?Akt in gastric cancer cells. The in vitro growth of SGC?7901, Hs746T and MKN28 gastric cancer cells was found to be dose?dependently inhibited by oxaliplatin and SAHA. Furthermore, combined treatment was observed to be more effective in inhibiting cancer cell growth and colony formation than monotherapy. Similar effects were found in the xenografts. A positive interaction was identified between oxaliplatin and SAHA (between?subject effects of oxaliplatin and SAHA, P<0.001). In addition, combined exposure to oxaliplatin and SAHA increased ?H2AX expression and decreased Bcl?2 expression. The expression of cleaved caspase?3 and PARP was also increased with combination treatment. Oxaliplatin?induced Src phosphorylation was detected in gastric cancer cells, as we have previously reported. However, this effect was inhibited by SAHA. The oxaliplatin?induced Src phosphorylation was not impaired with Akt inhibition. In conclusion, oxaliplatin and SAHA exhibited a positive interaction when used in combination and were found to suppress gastric cancer cell survival and growth. The reversal of oxaliplatin?induced Src activation may be responsible for this positive interaction.
Intestinal metaplasia (IM) has been recognized as the first irreversible precancerous stage of intestinal-type gastric cancer at which genetic instabilities, such as microsatellite instability and loss of heterozygosity, can already be detected. However, the extent and clonal relationship of these genetic lesions in the precancerous tissues are not fully appreciated. In this work, we have used well established microsatellite markers to analyze the relatedness of spatially separated individual metaplastic glands as well as sub-segments within single glands from the same patients. We found that individual IM glands frequently show different marker lengths even for closely apposed IM glands, suggesting that these tissues have already gained the ability to independently evolve their genome regardless of whether or not they share a common origin. Furthermore, within individual IM glands, there is also significant intra-gland diversity in the microsatellite markers. Since most of these cells are not dividing and only have a limited lifespan, this result indicates that in each IM gland, a single dominant clone is rare, and new clones are constantly created by either progenitor cells or stem cells. This greatly enhanced ability to create de novo genetic alterations may underlie the importance of this stage in the eventual progression toward cancer. Given the widely observed phenotype switch in the early stages of many solid tumors, whether this associated genetic stability is also an intrinsic property of metaplastic transformation should be extensively characterized to further our understanding of cancer initiation. This article is protected by copyright. All rights reserved.
Long non-coding RNAs (lncRNAs) play key roles in the progression and metastasis of some carcinomas. We previously showed that the expression of lncRNA H19 (H19) was higher in gastric cancer (GC) tissues than that in paired noncanerous tissues. However, the underlying mechanisms remain unclear. In this study, H19/miR-675 knockdown models in the MKN45 cell line and ectopic expression models in the SGC7901 cell line were established, and a co-expression network of H19 was generated to identify target genes by RIP and DLR. The results showed that overexpression of H19 promoted the features of GC including proliferation, migration, invasion and metastasis. An H19 co-expression network identified ISM1 as a binding protein of H19, and its expression was positively correlated with that of H19. CALN1 was identified as a target gene of miR-675 and its expression was negatively correlated with that of miR-675. H19 and MiR-675 function in a similar manner. However, H19 RNA actively binds to ISM1 and miR-675 targets CALN1. These differences suggest that H19 plays other roles besides encoding miR-675 in GC. Our results suggest that the effect of H19 in GC is mediated by the direct upregulation of ISM1 and the indirect suppression of CALN1 expression via miR-675.
Elevated MELK expression is featured in multiple tumors and correlated with tumorigenesis and tumor development. This study is aimed to investigate the mechanisms of MELK-mediated development of gastric cancer.
Individuals with gallbladder carcinoma (GBC), the most aggressive malignancy of the biliary tract, have a poor prognosis. Here we report the identification of somatic mutations for GBC in 57 tumor-normal pairs through a combination of exome sequencing and ultra-deep sequencing of cancer-related genes. The mutation pattern is defined by a dominant prevalence of C>T mutations at TCN sites. Genes with a significant frequency (false discovery rate (FDR)<0.05) of non-silent mutations include TP53 (47.1%), KRAS (7.8%) and ERBB3 (11.8%). Moreover, ErbB signaling (including EGFR, ERBB2, ERBB3, ERBB4 and their downstream genes) is the most extensively mutated pathway, affecting 36.8% (21/57) of the GBC samples. Multivariate analyses further show that cases with ErbB pathway mutations have a worse outcome (P=0.001). These findings provide insight into the somatic mutational landscape in GBC and highlight the key role of the ErbB signaling pathway in GBC pathogenesis.
Inhibitory effects and potential mechanisms of capecitabine metronomic chemotherapy on colon cancer were investigated in this study. Metronomic chemotherapy with fluorouracil or capecitabine inhibited proliferation of colon cancer cells both in vitro and in vivo. Capecitabine metronomic chemotherapy demonstrated equal effects as CTX metronomic chemotherapy. Metronomic capecitabine or CTX chemotherapy decreased vascular endothelial growth factor (VEGF) but elevated thrombospondin-1 (TSP-1) expression, reduced CEP levels and decreased microvessel density (MVD). These results indicated anti-angiogenesis may be correlated with the antitumor effects of metronomic capecitabine in colon cancer.
The functions of long non-coding RNAs (lncRNAs) in gastric cancer (GC) remain largely unknown. MALAT1 is a kind of lncRNA that had been validated as a pivotal metastasis and prognosis mark in lung adenocarcinoma. In this study, we found that MALAT1 was aberrantly highly expressed in GC cell lines (SGC-7901, MKN-45 and SUN-16), and induced specific distribution and over-expression of SF2/ASF in nucleolus. Knock-down of MALAT1 or SF2/ASF in SGC-7901 cells respectively induced significant arrest of cell cycle in G0/G1 phase along with a remarkable suppression of cell proliferation, and the nuclear distribution and expression of SF2/ASF was significantly impaired when MALAT1 was depleted. However, over-expression of SF2/ASF exhibited no effect on rescuing the cell proliferation suppression by MALAT1 depletion. These results suggest that MALAT1 may function as a promoter of GC cell proliferation partly by regulating SF2/ASF, and our findings may provide us a likely biomarker and a potential target for GC diagnosis and therapeutic treatment.
SOX11 is involved in gastrulation and in malignant diseases. The aim of this study was to investigate the role of SOX11 in gastric cancer and its expression pattern and clinical significance. SOX11 overexpression cell model was used to examine in vitro and in vivo the role of SOX11 in cell growth and metastasis. Cell cycle analysis and Annexin V/PI double staining were used to investigate the effect of SOX11 on cell cycle progression and apoptosis. The expression of SOX11 in human gastric cancer was examined by immunohistochemistry. The correlation of SOX11 expression with clinicopathological characteristics and survival of patients was analyzed by Pearson's ?(2) and Kaplan-Meier analyses, respectively. Cox's proportional hazard model was employed in multivariate analysis. SOX11 overexpression did not inhibit cell growth but strongly suppressed cell migration/invasion in vitro and in vivo. We found a significant correlation between high SOX11 protein levels and Lauren's classification (intestinal type), differentiation status (high and medium), and early TNM stage. SOX11 is an independent prognostic factor for improved survival in gastric cancer patients. SOX11 was a potential tumor-suppressor and an independent positive prognostic factor in gastric cancer patients with less advanced clinicopathological features.
Today, the comprehensive surgical treatment for gastrointestinal cancer is almost in the perfect stage. It is difficult to further improve the curative effect by surgery only. To improve the overall curative effect of gastrointestinal tumor, translational medicine research should be promoted in the fields of the early diagnosis, etiology and pathogenesis and comprehensive treatment. Researches of discovering the new tumor markers for early diagnosis of tumor, etiology and pathogenesis involve many aspects, including environmental factors, genetic susceptibility, variation and accumulation of genetics, and epigenetic changes, which should be transferred to new methods of treatment. This review summarizes the gastrointestinal tumor-associated hot topics in the field of basic research and its progress, and provides the clinical clues from their conversion.
Claudin 1 is one of the tight junction proteins, which are critical in the maintenance of epithelial integrity. Aberrant regulation of CLDN1 and its correlation with ?-catenin have been discovered in malignant tumors. The present study aimed to investigate the expression profile and clinical relevance of CLDN1 and ?-catenin. The protein levels of CLDN1 and ?-catenin were examined using immunohistochemical staining. The characteristics of expression profile and prognostic value were analyzed using Pearson's ?² test and Kaplan-Meier analysis, respectively. ?-catenin overexpression and knockdown were used to investigate its role in regulating CLDN1 expression. We showed that CLDN1 was overexpressed in intestinal-type, presence of lymph node metastasis, higher TNM stage in gastric cancer patients and correlated with decreased overall survival. The characteristics of CLDN1 expression were associated with that of ?-catenin. CLDN1 and ?-catenin showed similar prognostic value in intestinal-type gastric cancers. ?-catenin knockdown and overexpression in cell models revealed a positive relation between CLDN1 and ?-catenin. Our study demonstrated that CLDN1 is a biomarker for intestinal-type gastric cancer with shorter survival. The expression of CLDN1 was strongly associated with ?-catenin in gastric cancer patients and a gastric cancer cell model.
Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) shows increased expression in a wide variety of human cancers, and its over-expression is associated with enhanced migration, invasion, and in vivo metastasis. Here, we reported that CEACAM6 was up-regulated in gastric cancer (GC) cell lines and tumor tissues. Over-expression of CEACAM6 in MKN-45 and SGC-7901 GC cells promoted migration and invasion in vitro and metastasis in athymic mice, whereas migration and invasion of MKN-28 and SNU-16 GC cells were suppressed by knockdown of CEACAM6. We also observed that steroid receptor coactivator (C-SRC) phosphorylation was increased when CEACAM6 was over-expressed in SGC-7901 cells. Taken together, these results suggested that CEACAM6 functions as an oncoprotein in GC and may be an important metastatic biomarker and therapeutic target.
The value of noncurative resection for patients with gastric cancer with single peritoneal metastasis is still debatable. This study was undertaken to evaluate the survival benefit of resection in those patients. From 2006 to 2009, 119 patients with gastric cancer with single peritoneal metastasis were identified during surgery. Sixty-three of them had noncurative resection; the remainder had nonresection. Clinicopathological variables and survival were analyzed. Overall survival of patients in the noncurative resection group was longer than that in the nonresection group (14.869 vs 7.780 months). This survival advantage was still significantly better in the P1/P2 patients who underwent noncurative resection (mean survival time 21.164 vs 7.636 months, P = 0.001), but not in the P3 group (P = 0.489). Multivariate analysis indicated that only noncurative resection retained a significant association with better prognosis in P1/P2 patients. The perioperative mortality rate in the resection group was not significantly higher than that of the noncurative group (P = 0.747). Noncurative resection can prolong the survival of patients with gastric cancer with single P1/P2 peritoneal metastasis. This surgical approach should not be taken into account for those patients with P3 gastric cancer.
According to the World Health Organization, 800,000 cancer-related deaths are caused by gastric cancer each year globally, hence making it the second leading cause of cancer-related deaths in the world. Gastric cancer is often either asymptomatic or causing only nonspecific symptoms in its early stages. By the time the symptoms occur, the cancer has usually reached an advanced stage, which is one of the main reasons for its relatively poor prognosis. Therefore, early diagnosis and early treatment are very crucial. The differential analysis of serum protein between cancer patients and healthy controls can be performed using proteomics techniques and can hence be adopted as tumor biomarkers for the early diagnosis of cancer. So far, several serum tumor biomarkers have been identified for gastric cancer. However due to their poor specificity and sensitivity, they have proven to be insufficient for the reliable diagnosis of gastric cancer. Thus, using modern advanced proteomics techniques to find some new and reliable serum tumor biomarkers for earlier and reliable diagnosis of gastric cancer is a must. Nowadays, proteomic-based techniques, such as SELDI and HCLP, are available to discover biomarkers in gastric cancer. Numerous novel serum tumor biomarkers such as SAA, plasminogen and C9c, have been discovered through serological proteomics strategies. This review mainly focuses on the serum proteomics techniques and their application in the research of gastric cancer.
Mutation status of Kirsten rat sarcoma viral oncogene homolog (KRAS) may serve as a negative predictive marker of Cetuximab in treating colorectal cancer. The present study was to determine the role of KRAS status in EGFR antibody treatment for gastric cancer. KRAS status was clarified in SGC-7901 (wild type) and YCC-2 (G?A mutation) gastric cancer cell lines. Anti-proliferative and pro-apoptotic effects of Cetuximab were tested both in vitro and in vivo, the expression of phosphorylated (p) ERK, a downstream protein in EGFR-RAS-MEK pathway, was also analyzed. No significant in vitro anti-proliferative or pro-apoptotic effects of Cetuximab were observed in both cell lines. The growth of either SGC-7901 or YCC-2 gastric cancer xenograft was significantly inhibited by Cetuximab. Apoptosis was induced in SGC-7901 but not in YCC-2 xenografts after Cetuximab treatment. The expression of pERK was up-regulated in YCC-2 but not SGC-7901 xenografts after Cetuximab treatment. In conclusion, KRAS (G?A) mutation does not affect in vivo anti-cancer efficacy of Cetuximab.
microRNAs are small noncoding RNAs that modulate a variety of cellular processes by regulating multiple targets, which can promote or inhibit the development of malignant behaviors. Accumulating evidence suggests miR-24 plays important roles in human carcinogenesis. However, its precise biological role remains largely elusive. This study examined the role of miR-24 in gastric cancer (GC).
Progesterone is essential for the proliferation and differentiation of mammary gland epithelium. Studies of breast cancer cells have demonstrated a biphasic progesterone response consisting of an initial proliferative burst followed by sustained growth arrest. However, the transcriptional factors acting with the progesterone receptor (PR) to mediate the effects of progesterone on mammary cell growth and differentiation remain to be determined. Recently, it was demonstrated that signal transducer and activator of transcription 6 (Stat6) is a cell growth suppressor. Similar to progesterone-bound PR, Stat6 acts by inducing the expression of the G1 cyclin-dependent kinase inhibitors p21 and p27. The possible interaction between Stat6 and progesterone pathways in mammary cells was therefore investigated in the present study.
Overexpressed CEACAM6 in tumor tissues plays important roles in invasion, metastasis and anoikis resistance in a variety of human cancers. We recently reported that CEACAM6 expression is upregulated in Gastric cancer (GC) tissues and promoted GC metastasis. Here, we report that CEACAM6 promotes peritoneal metastases in vivo and is negatively correlated with E-cadherin expression in GC tissues. Overexpressed CEACAM6 induced epithelial-mesenchymal transition (EMT) in GC, as measured by increases in the EMT markers N-cadherin, Vimentin and Slug while E-cadherin expression was decreased in CEACAM6-overexpressing GC cells; opposing results were observed in CEACAM6-silenced cells. Furthermore, E-cadherin expression was negatively correlated with depth of tumor invasion, lymph node metastasis and TNM stage in GC tissues. Additionally, CEACAM6 elevated matrix metalloproteinase-9 (MMP-9) activity in GC, and anti-MMP-9 antibody could reverse the increasing invasion and migration induced by CEACAM6. CEACAM6 also increased the levels of phosphorylated AKT, which is involved in the progression of a variety of human tumors. We further observed that LY294002, a PI3K inhibitor, could reverse CEACAM6-induced EMT via mesenchymal-epithelial transition. These findings suggest that CEACAM6 enhances invasion and metastasis in GC by promoting EMT via the PI3K/AKT signaling pathway.
Sirtuin 2 (SIRT2) is a member of sirtuin protein family. Previous studies have suggested that SIRT2 plays differential roles in the survival and cell cycle regulation of various cell types. Because microglia plays critical roles in multiple major neurological disorders, in our current study we investigated the roles of SIRT2 in regulation of the cell cycle and cell survival of BV2 microglia by applying SIRT2 siRNA. We found that SIRT2 reductions by SIRT2 siRNA can produce cell cycle arrest of the cells at G0/G1 phase, by significantly increasing percentage of the cells in G0/G1 phase as well as decreasing percentage of the cells in S phase. The SIRT2 reductions can also increase late-stage apoptosis of the cells. We further found that SIRT2 silencing can lead to a decrease in the number of surviving BV2 cells, which may result from the effects of SIRT2 siRNA on both cell cycle and cell survival of the cells. Collectively, our study has suggested an important role of SIRT2 in regulating both the cell cycle and basal survival of microglia.
Toll-like receptor 4 (TLR4) is a receptor of lipopolysaccharide in the signaling transduction of gastric epithelial cell. It plays a pivotal role in activation of innate immunity and pathogen recognition and thus acts as a modulator in the development and progression of gastric cancer. Growing studies explored the association of polymorphisms in TLR4 with susceptibility to gastric cancer, but the results have remained controversial and conflicting. To investigate the effect of two selected TLR4 (+896A/G and +1196C/T) polymorphisms on gastric cancer, we performed a meta-analysis.
Pancreatic neuroendocrine tumor (pNET) is a clinically rare and heterogeneous group of tumors; its pharmacogenetic characteristics are not fully understood. This study was designed to examine the relationship between key gene variations and disease development and prognosis among Chinese patients with pNET.
We previously showed that Slit2 was highly expressed in gastric cancer tissues that exhibit less advanced clinicopathological features, suggesting a tumor suppressor role for Slit2. In the present study, we investigated the effects of Slit2 knockdown on gastric cancer cells. Slit2-specific shRNAs were used to generate Slit2-knockdown SGC-7901 gastric cancer cells. Cell proliferation assay, Annexin V/PI double staining and cell cycle analysis were used to investigate the role of Slit2 knockdown in cell growth. Wound-healing and in vitro migration/invasion assays were performed. Subcutaneous tumor formation and peritoneal spreading in nude mice were employed to examine the in vivo effects of Slit2 knockdown. Cell signaling changes induced by Slit2 knockdown were analyzed by immunoblotting. Slit2 knockdown increased gastric cancer cell growth in monolayer and soft agar/Matrigel 3D culture. Slit2 knockdown inhibited apoptosis but did not alter cell cycle progression. Slit2-knockdown cells formed larger tumors and produced more peritoneal metastatic nodules in nude mice. Slit2 knockdown increased AKT phosphorylation, activated anti-apoptotic signaling, suppressed GSK3? activity and induced ?-catenin activation. Blocking the effects of PI3K/AKT using pharmacological inhibitors abolished the ability of Slit2 knockdown to induce apoptosis resistance and cell migration/invasion. These results indicate that Slit2 knockdown promotes gastric cancer growth and metastasis through activation of the AKT/??catenin-mediated signaling pathway.
MicroRNAs (miRNAs) and promoter hypermethylation are vital epigenetic mechanisms for transcriptional inactivation of tumor suppressor. IRX1 is a newly identified tumor suppressor gene and hypermethylation involves the decreased expression in gastric cancer. However, the microRNA regulatory mechanism on IRX1 expression is still unclear. In this study, we report an IRX1-targeting miRNA-544, which directly targets 3-UTR of IRX1 gene by luciferase reporter assay. miR-544 suppresses the protein expression of IRX1 gene by Western blot and immunocytochemistry. Ectopic expression of miR-544 promotes cell proliferation and cell cycle progression significantly in vitro on gastric cancer cells. The study suggests that miR-544 is an oncogenic microRNA in gastric cancer. Over expression of miR-544 contributes to the inactivation and low-expression of IRX1 in gastric cancer. These findings are helpful for clarifying the molecular mechanisms involved in gastric carcinogenesis and indicate that miR-544 is a key regulator in switching cell cycle on or off. miR-544 may be a potential molecular target in miRNA-based strategy on gastric cancer.
Gastric cancer is the fourth most common cancer worldwide. Several signaling pathways are involved in gastric cancer development and progression. Slit2 was recently found to be involved in cancer; however, its expression pattern in gastric cancer has not been discovered yet. In the present study, we investigated the expression of Slit2 in human gastric cancer and its correlation with the expression and subcellular localization of ?-catenin. Immunohistochemistry (IHC) staining revealed that Slit2 was highly expressed in human gastric cancer tissues, while it was low or weakly expressed in normal gastric tissues. The differences in clinicopathological features between different groups were determined using Pearsons ?2 test. Slit2 levels were significantly associated with differentiation, Laurens classification, lymph node metastasis and TNM staging. Slit2 levels were positively correlated with ?-catenin level in gastric cancer tissues and cell lines. High levels of Slit2 were correlated with the membrane localization of ?-catenin, and low levels of Slit2 were correlated with nuclear translocation of ?-catenin in both gastric cancer tissues and cell lines assayed by IHC and immunofluorescence staining, respectively. Our data suggest that Slit2 was highly expressed in gastric cancer patients with less advanced clinicopathological features. Slit2 levels were correlated with ?-catenin level and subcellular localization.
V-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) is a member of CRK family and act as an adaptor protein participating in intra-cellular signal transduction. The role of CRKL in gastric cancer (GC) remains unclear. In this study, we show that CRKL was aberrantly highly expressed in both GC tumor specimens and cell lines (SGC-7901, MKN-45, MKN-28 and SUN-16). The expression of CRKL was significantly correlated with GC clinicopathologic features including tumor size, local invasion, lymph node metastasis and TNM stages. Knock-down of CRKL in SGC-7901 cells induced a suppression of cell proliferation along with a significant arrest of cell cycle in G0/G1 phase, however, no significant influence was observed on cell apoptosis. We validate that miR-126, a suppressor in GC, was a negative regulator of CRKL by directly combining with the 3 untranslated region of CRKL mRNA, and over-expression of miR-126 inhibited the protein expression of CRKL significantly. These results suggest that CRKL may function as an oncogene in GC by promoting the GC cell proliferation, which provides us a likely biomarker and a potential target for GC prevention, diagnosis and therapeutic treatment. Moreover, the targeting relationship between CRKL and miR-126 partly reveals the mechanism of miR-126 on GC suppression.
L-type amino-acid transporter 1 (LAT-1) is a member of system L-type transporters, essential for cells maintenance and proliferation. However, the role of LAT-1 remains illegible in gastric cancer (GC). In this study, we found that LAT-1 was aberrantly up-regulated in both GC cell lines (MKN-45, MGC-803 and CRL-5974) and human GC specimens. The expression characteristic of LAT-1 in GC was significantly associated with clinicopathologic features such as tumor size, lymph node metastasis, local invasion and TNM stage. By suppressing the expression of LAT-1 in MKN-45 cells, the cell cycle was arrested in G0/G1 phase, and the ability of cell proliferation was significantly decreased in vitro. Moreover, the cell migration and invasion of MKN-45 cells was significantly impaired by knocking down LAT-1. Thus, our results suggest that LAT-1 may function as an oncogene in GC, which provides us a new biomarker in GC and perhaps a potential target for GC prevention, diagnose and therapeutic treatment.
HIC1 is a tumor suppressor gene that is down-expressed in different malignancies, in part, because of promoter hypermethylation. However, the biological function of HIC1 in gastric cancer remains unclear. It is known that small double-stranded RNAs can induce gene expression by targeting promoter sequences. In the present study, we examined the expression levels of HIC1 in gastric cancer tissue. Several pieces of small double-stranded RNAs were used for the activation of HIC1. Tissue microarray analysis of gastric cancer indicated that down-regulation of HIC1 in gastric cancer tissue was dramatic compared with the adjacent gastric mucosa. Gastric cancer cell lines also showed down-regulated HIC1 expression compared with a human immortalized gastric mucosa cell line. One out of four dsRNAs produced activation of HIC1 as assessed by real-time PCR and Western blotting. Use of a cell counting kit 8 and clonogenicity assays indicated that dsRNA-mediated re-expression of HIC1 inhibited cell proliferation and clonogenicity in gastric cancer. Reactivation of HIC1 suppressed cell migration and induced cell cycle arrest in the G0/G1 phase, as well as induced apoptosis. These results suggest that HIC1 is a potential target of gene therapy against gastric cancer, and that dsRNAs could function as a therapeutic option for up-regulating tumor suppressor genes in gastric cancer and other malignancies.
Secreted frizzled-related protein 1 (sFRP1), Wnt signalling regulator, can positively or negatively regulate tumourigenesis and progression. We sought to determine the clinical relevance and the role of sFRP1 in gastric cancer development and progression.
Fibroblasts play a critical role in tumorigenesis, tumor progression and metastasis. However, their detailed molecular characteristics and clinical significance are still elusive. TAGLN is an actin-binding protein that plays an important role in tumorigenesis.
To evaluate the expression of chromodomain helicase/adenosine triphosphatase DNA binding protein 1-like gene (CHD1L) in colorectal carcinoma (CRC) and its clinical significance. Its oncogenic ability was also investigated.
Cancer-associated fibroblasts (CAFs), as the activated fibroblasts in tumor stroma, are important modifiers of tumor progression. However, the mechanisms underlying stromal fibroblast activation and their promotion of tumor growth remain largely unknown in gastric cancer. Here, we show that normal fibroblasts (NFs) from non-cancerous regions of gastric cancer exhibit the traits of CAFs when grown together with gastric cancer cells in vivo. Activation of NFs can be induced by co-culture with gastric cancer cells, while deprivation of hepatocyte growth factor (HGF) using a neutralizing antibody inhibits the activation of NFs. Moreover, we identify HGF as an important factor from CAFs that acts in a paracrine manner to promote tumorigenesis in vitro and in vivo. Taken together, these results suggest that HGF may play a pivotal role in the regulatory circuit between gastric cancer cells and stromal fibroblasts, and neutralization of HGF inhibits both activation and tumor-promoting properties of CAFs.
MicroRNAs can promote or suppress the evolution of malignant behaviors by regulating multiple targets. We aimed to determine the expression of miR-301a recently screened in gastric cancer, to investigate the biological effects of miR-301a and to identify the specific miR-301a target gene.
BACKGROUND: Chromosomal instability caused by abnormal cell division is a major cause of heterogeneity which evokes highly complex and malignant features of gastric cancer. Hec1/Ndc80 is critical in regulating proper cell division at the G2/M phase. The aim of our study is to investigate the in vitro and in vivo effects of Hec1 on gastric cancer cell growth. METHODS: The mRNA levels of Hec1 in human normal and cancer tissues were analyzed using the Oncomine database. Hec1 mRNA and protein levels in human gastric cancer tissues were analyzed by quantitative realtime-PCR and immunohistochemical staining, respectively. The effects of Hec1 on cell growth were explored by Hec1 knockdown and Hec1 overexpression. Apoptosis and cell cycle distributions were analyzed by flow cytometry. In vivo tumorigenicity was performed by engrafting tumor cells into nude mice. RESULTS: Hec1 mRNA and protein were broadly overexpressed in many human cancers including gastric cancer. Hec1 knockdown dramatically suppressed gastric cancer cell growth in vitro and in vivo, induced apoptosis, and arrested cell division at the G2/M phase. On the contrary, Hec1 overexpression moderately promoted gastric cancer cell growth in vivo. Hec1 overexpression induced asymmetrical chromosome alignments, abnormal cell division, and thus rendered chromosomal instability. CONCLUSIONS: Hec1 is critical in maintaining the in vitro and in vivo growth of gastric cancer cells. Elevated Hec1 levels may occur at the early stage of gastric tumorigenesis.
Multiple myeloma (MM) is a plasma cell dyscrasia characterized by bone lesions and production of a paraprotein. B-lymphocyte stimulator (BLyS) and its receptor (BAFFR) were highly expressed on peripheral blood and bone marrow B cells in MM patients as compared to those with monoclonal gammopathy of unknown significance (MGUS) and healthy donors. Serum BLyS levels in MM patients were significantly higher than those in MGUS patients and healthy controls. BLyS expression was increased in bone marrow specimens from MM patients as ascertained by immunofluorescence. Furthermore, BLyS, together with IL-2 and IL-6, significantly promoted MM cell proliferation and BLyS receptor expression compared with that in the control group. Treatment with bortezomib, a therapeutic proteasome inhibitor induced apoptosis and repressed the proliferation of RPMI8226 and U266 cells through inhibition of NF-?B p65 and I?B?. These findings suggest that BLyS is involved in the immunopathogenesis of MM and may prove to be a hallmark of MM.
Because billions of cells die every day in their bodies, animals have evolutionarily developed apoptosis to preserve the tissue environment from adverse effects of dead cells, a process achieved via phagocytosis of the cell corpses by professional or amateur phagocytes that are collectively referred to as scavengers. Hence, apoptosis is a merger of two procedures separately occurring inside the dying and the scavenger cells, respectively. The task of apoptosis research is to study how these death procedures occur without hurting the host tissues, and recruitment of in vitro system into the study must be justified for this purpose. Cells in culture have no motivation to preserve the environment, and their death does not involve corpse clearance by scavengers. Therefore, programmed cell death in culture should be redefined, for example as stress-induced cell death, to avoid many sources of confusions, since the word "apoptosis" had already been defined, prior to the era of cell culture, as a silent and beneficial cell suicide with corpse clearance as a distinctive hallmark. We should start over again on apoptosis research by determining whether different physiological apoptotic procedures in animals involve the cytochrome c-caspase pathway, since it has been established from cultured cells as a central mechanism of "apoptosis" but whether it overarches any physiological apoptotic procedure in animals is still unclear. Probably, cells in living animals are programmed to use scavengers to assist their apoptosis but cells in culture have no scavengers to help and thus need to go mainly through the cytochrome c-caspase pathway.
Therapeutic antibody development is one of the fastest growing areas of the pharmaceutical industry. Generating high-quality monoclonal antibodies against a given therapeutic target is crucial for successful drug development. However, due to immune tolerance, making it difficult to generate antibodies using conventional approaches.
Emerging studies have indicated that microRNAs are involved in the development and progression of cancer. Here we found that miR-202-3p was frequently down-regulated in gastric cancer tissues. Overexpression of miR-202-3p in gastric cancer cells MKN-28 and BGC-823, markedly suppressed cell proliferation and induced cell apoptosis both in vitro and in vivo. Furthermore, Gli1 expression was frequently positive in gastric cancer tissues and inversely correlated with miR-133b expression. We demonstrate that the transcriptional factor Gli1 was a target of miR-202-3p and plays an essential role as a mediator of the biological effects of miR-202-3p in gastric cancer. MiR-202-3p also inhibited the expression of ?-catenin and BCL-2. Taken together, these findings suggest that miR-202-3p may function as a novel tumor suppressor in gastric cancer and its anti-tumor activity may attribute the direct targeting and inhibition of Gli1.
MicroRNA has been recently recognized as playing a prominent role in tumorigenesis and metastasis. Here, we report that miR-338-3p was epigenetically silenced in gastric cancer, and its down-regulation was significantly correlated with gastric cancer clinicopathological features. Strikingly, restoring miR-338-3p expression in SGC-7901 gastric cancer cells inhibited proliferation, migration, invasion and tumorigenicity in vitro and in vivo, at least partly through inducing apoptosis. Furthermore, we demonstrate the oncogene SSX2IP is a target of miR-338-3p. We propose that miR-338-3p functions as a tumor suppressor in gastric cancer, and the methylation status of its CpG island could serve as a potential diagnostic marker for gastric cancer.
Rheumatoid arthritis is an autoimmune disease that primarily affects the limbs, but the pathogenic mechanism remains unclear. ?? T cells, a T-cell subpopulation, are characterized by multiple biological functions and associated with a variety of diseases. This study investigated the antigen-presenting effects of ?? T cells and their relationship with rheumatoid arthritis development. We found that V?9V?2 T cells (the predominant subtype of ?? T cells in peripheral blood) were activated by isopentenyl pyrophosphate to continuously proliferate and differentiate into effector memory cells. The effector memory V?9V?2 T cells exhibited phenotypic characteristics of specific antigen-presenting cells, including high HLA-DR and CD80/86 expression. These V?9V?2 T cells could present soluble antigens and synthetic peptides to CD4(+) T cells. V?9V?2 T cells with different phenotypes showed different cytokine secretion patterns. Effector memory V?9V?2 T cells simultaneously secreted not only interferon (IFN)-? but also IL-17. The peripheral blood and joint synovial fluid from RA patients contained numerous heterogeneous ?? T cells that were predominantly effector memory V?9V?2 T cells with the ability to secrete inflammatory factors. We also found that ?? T cells had a similar antigen-presenting capability to B cells. These results suggest that during the development of rheumatoid arthritis, ?? T cells can aggravate immune dysfunction and produce abnormal immune damage by secreting cytokines and inducing inflammatory cells to participate in synergistic inflammatory responses. Furthermore, ?? T cells can behave similarly to B cells to present viral peptides and autoantigen peptides to CD4(+) T cells, thus sustaining CD4(+) T-cell activation.
Recent studies demonstrated that in several human malignancies aberrant expression profiles of circulating microRNAs (miRNAs) anticipate great cancer diagnostic potential. Here we showed that serum miR-378 could serve as a novel noninvasive biomarker in gastric cancer (GC) detection. Genome-wide miRNA expression profiles followed with Real-Time quantitative RT-PCR (qRT-PCR) assays revealed that miR-187(*), miR-371-5p and miR-378 were significantly elevated in GC patients. Further validation indicated that miR-378 alone could yields a ROC curve area of 0.861 with 87.5% sensitivity and 70.73% specificity in discriminating GC patients from healthy controls. Collectively, these data support our contention that serum miR-378 has strong potential as a novel noninvasive biomarker in gastric cancer detection.
Cyclin D1 is aberrantly expressed in many types of cancers, including breast cancer. High levels of cyclin D1b, the truncated isoform of cyclin D1, have been reported to be associated with a poor prognosis for breast cancer patients. In the present study, we used siRNA to target cyclin D1b overexpression and assessed its ability to suppress breast cancer growth in nude mice. Cyclin D1b siRNA effectively inhibited overexpression of cyclin D1b. Depletion of cyclin D1b promoted apoptosis of cyclin D1b-overexpressing cells and blocked their proliferation and transformation phenotypes. Notably, cyclin D1b overexpression is correlated with triple-negative basal-like breast cancers, which lack specific therapeutic targets. Administration of cyclin D1b siRNA inhibited breast tumor growth in nude mice and cyclin D1b siRNA synergistically enhanced the cell killing effects of doxorubicin in cell culture, with this combination significantly suppressing tumor growth in the mouse model. In conclusion, the results indicate that cyclin D1b, which is overexpressed in breast cancer, may serve as a novel and effective therapeutic target. More importantly, the present study clearly demonstrated a very promising therapeutic potential for cyclin D1b siRNA in the treatment of cyclin D1b-overexpressing breast cancers, including the very malignant triple-negative breast cancers.
Protein tyrosine phosphatase 1B (PTP1B), a member of the superfamily of protein tyrosine phosphatases, has been implicated in cancer pathogenesis. However, the role of PTP1B in the development of gastric cancer is unclear. The purpose of this study was to clarify the expression pattern and role of PTP1B in the gastric cancer. The expression of PTP1B in gastric cancer tissues was determined by immunohistochemical staining. Cell growth assay, soft agar colony formation assay, and tumorigenicity assay were used for examining proliferation, colony formation, and in vivo tumorigenesis of gastric cancer cells. The total levels and phosphorylated levels of Akt, extracellular signal-regulated kinase (Erk1/2), focal adhesion kinase (FAK), and Src were examined by western blotting, respectively. PTP1B was overexpressed in gastric cancer tissues (65/80) and correlated with tumor metastasis and tumor-node-metastasis stage. Overexpression of PTP1B promoted the proliferation and in vivo tumorigenesis of MKN45 cells and also increased the phosphorylation levels of Akt, Erk1/2, and FAK and the activity of Src. These results were conformed by knockdown of PTP1B in MKN28 cells. Therefore, our study suggested that PTP1B expression might play an important role in the development of gastric cancer.
Overexpression of Aurora kinase A (AURKA) is frequently observed in various cancers, including laryngeal squamous cell carcinoma (LSCC). We investigated the effects of knockdown of AURKA on laryngeal cancer HEp-2 cells both in vitro and in vivo. A plasmid containing short hairpin (sh)RNA against AURKA was constructed and transfected into HEp-2. Measurements included the CCK-8 assay for viability and proliferation, flow cytometry for apoptosis and effects on the mitotic checkpoint, a trans-well assay for migration, immunofluorescence for assessment of genomic instability, and western blotting for protein expression. AURKA knockdown inhibited proliferation, migration, and colony formation in vitro and tumorigenicity in vivo. The knockdown induced the accumulation of cells in G2-M phase and eventual apoptosis. Knockdown of AURKA caused delayed entry into mitosis after treatment with nocodazole, reduced chromosomal instability, and decreased expression of focal adhesion kinase (FAK), phosphorylated FAK, and matrix metalloproteinase-2 (MMP-2), key regulators in cell adhesion and invasion. Knockdown of AURKA inhibits the growth and invasiveness of this LSCC cell line both in vitro and in vivo. These effects may partially result from the reduced expression of FAK and MMP-2. Knockdown of AURKA expression may represent a promising therapeutic strategy for the treatment of LSCC.
The purpose of the study was to investigate the expression of Aurora-A in human laryngeal squamous cell carcinoma (LSCC) and to explore the effects of Aurora-A silencing on invasion and chromosomal instability in laryngeal cancer HEp-2 cells. The expression of Aurora-A mRNA and protein were studied using reverse transcription-PCR and Western blot in LSCC tissues and corresponding normal epithelium, respectively. In addition, the correlation between Aurora-A expression and clinicopathologic characteristics was analyzed in LSCC patients. Furthermore, HEp-2 cells were transfected with Aurora-A short hairpin RNA and the effects of knockdown of Aurora-A on tumor invasion and chromosomal instability were investigated. The results showed that expression of Aurora-A mRNA was significantly upregulated in laryngeal tumor tissue compared with that in normal tissue (P = 0.001), and overexpression of Aurora-A was found in 64.0% (16 of 25) of the patients by Western blotting. Upregulation of Aurora-A mRNA was significantly correlated with regional lymph node metastasis (P = 0.007) and clinical stage III/IV (P = 0.022). Overexpression of Aurora-A was significantly associated with lymph node metastasis (P = 0.027). Furthermore, disruption of Aurora-A using RNA interference technique suppressed invasive ability and chromosomal instability in HEp-2 cells. In conclusion, Aurora-A expression is elevated in human LSCC and associated with regional lymph node metastasis and late clinical stage. Overexpression of Aurora-A may contribute to LSCC carcinogenesis and progression partially due to enhancement of invasion ability and chromosomal instability.
Gastric cancer is the second most common cause of global cancer-related mortality. Although dedifferentiation predicts poor prognosis in gastric cancer, the molecular mechanism underlying dedifferentiation, which could provide fundamental insights into tumor development and progression, has yet to be elucidated. Furthermore, the molecular mechanism underlying the effects of hexamethylene bisacetamide (HMBA), a recently discovered differentiation inducer, requires investigation and there are no reported studies concerning the effect of HMBA on gastric cancer.
The acquisition of resistance to 5-FU is one of the most prominent obstacles to successful chemotherapy, and the mechanisms underlying the resistance are not fully understood. The aim of this study is to identify novel mediators of 5-FU resistance in colon cancer cells.
The mechanisms governing tumorigenesis of gastric cancer have been an area of intense investigation. Currently, plant homeodomain (PHD) finger (PHF) proteins have been implicated in both tumor suppression and progression. However, the function of PHF10 has not been well characterized. Here, we show that various levels of PHF10 protein were observed in gastric cancer cell lines. Alteration of PHF10 expression, which is associated with tumor cell growth, may result in apoptosis in gastric cancer cells both in vitro and in vivo. Knockdown of PHF10 expression in gastric cancer cells led to significant induction of caspase-3 expression at both the RNA and protein levels and thus induced alteration of caspase-3 substrates in a time-dependent manner. Moreover, results from luciferase assays indicated that PHF10 acted as a transcriptional repressor when the two PHD domains contained in PHF10 were intact. Combined with previous findings, our data suggest that PHF10 transcriptionally regulates the expression of caspase-3. Finally, by using systematic reporter deletion and chromatin immunoprecipitation assays, we localized a region between nucleotides -270 and -170 in the caspase-3 promoter that was required for the efficient inhibition of caspase-3 promoter activity by PHF10. Collectively, our findings show that PHF10 repressed caspase-3 expression and impaired the programmed cell death pathway in human gastric cancer at the transcriptional level.
Deregulation of E2F1 activity is characteristic of gastric tumorigenesis, which involves in complex molecular mechanisms. microRNA is one of the post-transcriptional regulators for gene expression. Here, we report a member of miR-331 family, miR-331-3p, which was decreased in some kinds of malignancies. However, the biological function of miR-331-3p on gastric cancer is largely unknown. In this study, we screened the expressing levels of miR-331-3p and E2F1 in gastric cancer cell lines. We transfected precursor or inhibitor of miR-331-3p into gastric cancer cells. As results, miR-331-3p is down-regulated in all gastric cancer cell lines by real-time PCR. Over-expression of miR-331-3p blocked G1/S transition on SGC-7901 and AGS cell lines. Introduction of miR-331-3p dramatically suppressed the ability of colony formation and cell growth in vitro by interfering E2F1 activity. Our data highlight an important role of miR-331-3p in cell cycle control by targeting 3-UTR of cell cycle-related molecule E2F1. We concluded that miR-331-3p is a potential tumor suppressor in gastric cancer. Restoring miR-331-3p in gastric cancer cells revealed potential application in gastric cancer therapy.
Gene expression signatures for a basal-like breast cancer (BLBC) subtype have been associated with poor clinical outcomes, but a molecular basis for this disease remains unclear. Here, we report overexpression of the transcription factor FOXC1 as a consistent feature of BLBC compared with other molecular subtypes of breast cancer. Elevated FOXC1 expression predicted poor overall survival in BLBC (P = 0.0001), independently of other clinicopathologic prognostic factors including lymph node status, along with a higher incidence of brain metastasis (P = 0.02) and a shorter brain metastasis-free survival in lymph node-negative patients (P < 0.0001). Ectopic overexpression of FOXC1 in breast cancer cells increased cell proliferation, migration, and invasion, whereas shRNA-mediated FOXC1 knockdown yielded opposite effects. Our findings identify FOXC1 as a theranostic biomarker that is specific for BLBC, offering not only a potential prognostic candidate but also a potential molecular therapeutic target in this breast cancer subtype.
PTP1B (protein tyrosine phosphatase 1B) is a member of the superfamily of PTPs (protein tyrosine phosphatases) and has been implicated in cancer pathogenesis. However, the role of PTP1B in gastric cancer is still unknown. Here, we first detected the PTP1B expression in six gastric cancer cell lines and in the immortalized gastric mucosal epithelial cell line GES-1 by RT-PCR and Western blot. Then, we measured the change of the genome-wide expression profile in MKN28 gastric cancer cells transfected with a plasmid expressing PTP1B-specific small interfering RNA by microarray analysis. Our results showed that PTP1B was overexpressed in gastric cancer cells, and inhibition of PTP1B expression dramatically inhibited gastric cancer cell growth in vitro and in vivo. In addition, microarray analysis revealed that inhibition of PTP1B induced changes in the genome-wide expression profile. These changes may be related to cell growth. Taken together, our data suggested that PTP1B may be a candidate oncogene in gastric cancer.
MicroRNAs have emerged as important gene regulators and are recognised as key players in carcinogenesis. In the present study, we show that miR-126 was significantly down-regulated in gastric cancer tissues compared with matched normal tissues and was associated with clinicopathological features, including tumour size, lymph node metastasis, local invasion and tumour-node-metastasis (TNM) stage. Ectopic expression of miR-126 in SGC-7901 gastric cancer cells potently inhibited cell growth by inducing cell cycle arrest in G0/G1 phase, migration and invasion in vitro as well as tumorigenicity and metastasis in vivo. Mechanistically, we identified the adaptor protein Crk as a target of miR-126. Taken together, our results suggest that miR-126 may function as a tumour suppressor in gastric cancer, with Crk as a direct target.
Cancer cells have an efficient antioxidant system to counteract their increased generation of ROS. However, whether this ability to survive high levels of ROS has an important role in the growth and metastasis of tumors is not well understood. Here, we demonstrate that the redox protein thioredoxin-like 2 (TXNL2) regulates the growth and metastasis of human breast cancer cells through a redox signaling mechanism. TXNL2 was found to be overexpressed in human cancers, including breast cancers. Knockdown of TXNL2 in human breast cancer cell lines increased ROS levels and reduced NF-?B activity, resulting in inhibition of in vitro proliferation, survival, and invasion. In addition, TXNL2 knockdown inhibited tumorigenesis and metastasis of these cells upon transplantation into immunodeficient mice. Furthermore, analysis of primary breast cancer samples demonstrated that enhanced TXNL2 expression correlated with metastasis to the lung and brain and with decreased overall patient survival. Our studies provided insight into redox-based mechanisms underlying tumor growth and metastasis and suggest that TXNL2 could be a target for treatment of breast cancer.
Galectin-9, a member of galectin family, plays multiple roles in a variety of cellular functions, including cell adhesion, aggregation, and apoptosis. Galectin-9 also has three isoforms (named galectin-9L, galectin-9M, and galectin-9S), but whether these isoforms differ in their functions remains poorly understood. In this study, we showed that transient expression of galectin-9L decreased E-selectin levels, while transient expression of galectin-9M or galectin-9S increased E-selectin levels in LoVo cells, which do not express endogenous galectin-9. We also found that over-expression of three galectin-9 isoforms led to increased attachment of LoVo cells to extracellular matrix proteins respectively, while over-expression of galectin-9M or galectin-9S increased the adhesion of LoVo cells to human umbilical vein endothelial cells in vitro. In summary, these findings indicate that different isoforms of galectin-9 exhibit distinct biological functions.
Elesclomol is a small-molecule investigational agent that selectively induces apoptosis in cancer cells by increasing oxidative stress. Elesclomol plus paclitaxel was shown to prolong progression-free survival compared with paclitaxel alone in a phase II clinical trial in patients with metastatic melanoma. However, the therapeutic potential of elesclomol in human breast cancer is unknown, and the signaling mechanism underlying the elesclomol effect is unclear. Here, we show that elesclomol alone modestly inhibited the growth of human breast cancer cells but not normal breast epithelial cells. Elesclomol potentiated doxorubicin- or paclitaxel-induced apoptosis and suppression of breast cancer cell growth. While both c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase were activated by elesclomol, elesclomol-induced apoptosis was only in part mediated by JNK1. The additive effect of elesclomol on chemotherapy drug-induced apoptosis was associated with increases in cleaved caspase-3, p21(Cip1), and p27(Kip1) and decreases in the Inhibitor of Apoptosis Protein levels and NF-kappaB activity. We also found that Akt/Hsp70 survival signaling was induced by elesclomol, which may reflect a cellular feedback mechanism. Blockade of Akt activation using a small-molecule inhibitor enhanced elesclomol-elicited apoptosis, while expression of a hyperactive Akt abolished the elesclomol effect. These data suggest that elesclomols interaction with conventional chemotherapeutic and Akt-targeting agents may be exploited to induce apoptosis in breast cancer cells, and clinical trials of combined treatment of elesclomol and chemotherapy drugs or Akt-targeting agents in breast cancer patients, especially the estrogen receptor negative subgroup, may be warranted.
Insufflation with standard cold-dry CO(2) during laparoscopic surgery has been shown to predispose patients to hypothermia and peritoneal injury. This study aimed to compare the effect of prolonged cold-dry CO(2) insufflation with heated-humidified CO(2) insufflation (3-5 h) on hypothermia, peritoneal damage, and intra-abdominal adhesion formation in a rat model.
Gastric cancer (GC) remains a leading cause of death worldwide, and an elevated expression of osteopontin (OPN) may correlate with its poor survival. Alternative splicing of OPN can result in three isoforms, OPN-a, OPN-b and OPN-c. The aim of our current study is to examine the expression pattern and biological functions of OPN splice variants in GC.
In this study, we analyzed the protein expression of thioredoxin domain containing 9 (TXNDC9) in 116 colorectal cancer (CRC) cases. Among them, 97 were positive in CRC tissues and 60 were positive in normal mucosa. TXNDC9 expression in CRC was correlated with the extent of tumor invasion and the tumor size. TXNDC9-negative patients had longer lifespans. In vitro assays showed the significant suppression of CRC cell proliferation (P < .01) compared with two control groups; the number of invaded cells also decreased (P < .01). These findings suggest that TXNDC9 gene may function in cancer development and may be an effective target for inhibiting the growth and metastasis of CRC cells.
This study focuses on the association between the ABO blood group system and the risk of gastric cancer or Helicobacter pylori infection. The data for the ABO blood group was collected from 1045 cases of gastric cancer, whereby the patient underwent a gastrectomy in Ruijin Hospital, Shanghai. The information on the ABO blood group from 53,026 healthy blood donors was enrolled as control. We searched the Pubmed database on the relationship between ABO blood groups and gastric cancer risk for meta-analysis. In our case-control study, the risk of gastric cancer in blood group A was significantly higher than that in non-A groups (O, B and AB) (odd ratio, OR1.34; 95% confidential interval, CI 1.25-1.44). Compared with non-O groups (A, B and AB), individuals with blood group O demonstrated a reduced risk of gastric cancer (OR = 0.80; 95% CI 0.72-0.88). The proportion of H. pylori infection in blood group A individuals was significantly higher than that in non-A blood groups (OR = 1.42; 95% CI 1.05-1.93). We further combined our data with the published data of others, and crossreferenced the risk of gastric cancer with the blood type, finding consistent evidence that gastric cancer risk in the blood A group was higher than that in the non-A groups (OR = 1.11; 95% CI 1.07-1.15), and that blood type O individuals were consistently shown gastric cancer risk reduction (OR = 0.91; 95% CI 0.89-0.94). Our study concluded that there was a slightly increased risk of gastric cancer in blood group A individuals, and people with blood type A are more prone to be infected by H. pylori than other ABO blood type individuals, whereas, a slightly decreased risk of gastric cancer was identified in blood type O individuals.
Iron deficiency anemia is an extra-stomach disease experienced in H. pylori carriers. Individuals with type A blood are more prone to suffering from H. pylori infection than other individuals. To clarify the molecular mechanisms underlying H. pylori-associated anemia, we collected erythrocytes from A, B, O, and AB blood donors and analyzed morphology, the number of erythrocytes with H. pylori colonies attached to them, and iron contents in erythrocytes and H. pylori (NCTC11637 and SS1 strains) by means of optical microscopy, scanning electron microscopy, and synchrotron radiation soft X-ray imaging. The number of type A erythrocytes with H. pylori attached to them was significantly higher than that of other erythrocytes (P<0.05). Far more iron distribution was observed in H. pylori bacteria using dual energy analysis near the iron L2, 3 edges by soft X-ray imaging. Iron content was significantly reduced in host erythrocytes after 4 hours of exposure to H. pylori. H. pylori are able to adhere more strongly to type A erythrocytes, and this is related to iron shift from the host to the bacteria. This may explain the reasons for refractory iron deficiency anemia and elevated susceptibility to H. pylori infection in individuals with type A blood.
The signal transducer and activator of transcription 6 (Stat6), a member of the family of DNA-binding proteins, has been identified as a critical cell differentiation modulator in breast cancer cells. As of yet, the mechanisms underlying this function have remained largely unknown. To further elucidate the role of Stat6 in breast cancer development, we investigated the consequences of exogenous Stat6 expression.
Accumulating evidence has shown that microRNAs are involved in multiple processes in cancer development and progression. Here, we report that expression of miR-625 is significantly down-regulated and negatively correlated with lymph node metastasis in gastric cancer. miR-625 significantly inhibits invasion and metastasis of gastric cancer cells both in vitro and in vivo. Moreover, we identify that ILK is a direct target gene for miR-625 and knockdown of ILK has a phenocopy of overexpression of miR-625. Taken together, our findings suggest that miR-625 plays an important role in the mechanism of tumor metastasis.
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