Intervertebral disk degeneration has been considered an irreversible process characterized by a decrease in cell viability, attenuation of proteoglycan and type II collagen synthesis, and dehydration of nucleus pulposus. Stem cell therapy specifically addresses the degenerative process and offers a potentially effective treatment modality. Current preclinical studies show that mesenchymal stem cells have the capacity to repair degenerative disks by differentiation toward chondrocyte-like cells, which produce proteoglycans and type II collagen. There has been evidence that mesenchymal stem cell transplantation into the intervertebral disk increases the intradiskal magnetic resonance imaging T2 signal intensity, increases the disk height, and decreases the degenerative grade in animal models. Appropriate selection of cell carriers/matrix is important because it may prevent cell leakage into the spinal canal and provide an environment that facilitates cell proliferation and differentiation. Although human cell therapy trials for degenerative disk disease are on the horizon, potential issues might arise. The authors hereby review the current state of regenerative cell therapy in degenerative disk disease, with emphasis in cell source, techniques for cellular expansion, induction, transplantation, potential benefit, and risks of the use of this novel medical armamentarium in the treatment of degenerative disk disease.
Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, is reported to exert anti-tumor effects by upregulating the expression of the natural killer group 2D (NKG2D) ligands on tumor cells; however, the mechanisms vary in different tumor types, and the effect and mechanism of action of VPA in pancreatic cancer cells are unknown.
The LIM proteins (Lhx1, Lhx2, Lhx3 and Lhx4) have been report to play important roles in human development. The function role of Lhxs have been characterized in various tumor tissues as cancer suppressors or promoters in different can status and types. The aim of present study was to clarify the function role of Lhx proteins in human pancreatic ductal adenocarcinoma (PDA). The gene expression profiles of Lhxs was evaluated using real-time quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) analysis and immunohistochemistry in human PDA tissues compared with normal pancreatic tissues, which identified the gene overexpression of Lhx2 in PDA. Furthermore, we discovered that Lhx2 promoted cancer cell proliferation in vitro/vivo and elevated ?-catenin levels correlated with Lhx2 expression in PDA while the Lhx2 simulated ?-catenin activation was required for LMO1's oncogenic effects. Mechanistically, Lhx2 facilitate TCF4 to bind to ?-catenin and form a stable Lhx2/TCF4/?-catenin complex and trans-active its downstream target gene. Lhx2 mutations that disrupt the Lhx2-?-catenin interaction partially prevent its function in tumor cells.
Necrotic tissue infection can worsen the prognosis of severe acute pancreatitis (SAP), and probiotics have been shown to be beneficial in reducing the infection rate in animal experiments and primary clinical trials. However, the results of multicenter randomized clinical trials have been contradictory. Our aim in this study was to systematically review and quantitatively analyze all randomized controlled trials with regard to important outcomes in patients with predicted SAP who received probiotics.
Solid pseudopapillary tumors (SPTs) are a rare pancreatic neoplastic lesion. Familial aggregation has not been reported in this disease. The objectives of this study were to report the history, clinicopathological features, and gene mutations of 3 familial cases of SPT. Three female cases of SPT presented in 1 family. Eight family relatives, 5 healthy volunteers, and 8 patients with SPT acted as controls. Histological examination and immunohistochemistry were performed on the surgical tumor specimens. Polymerase chain reaction-single-strand conformation polymorphism and gene sequencing were performed on genomic DNA extracted from blood. All 3 patients underwent surgical treatment, 2 patients died (3 months and 5 months after surgery), whereas neither recurrence nor metastasis was observed in the other patient during 2-year follow-up. The tumors from the 3 cases had identical immunoreactivity to a series of molecular markers. A Leu104Val mutation of protease serine 1 (PRSS1) was observed in the familial patients and 2 healthy male family members; no ?-catenin or adenomatous polyposis coli mutations were detected in the familial cases. This study indicates the possibility of genetic involvement in the pathogenesis of SPT. Family history may be a positive predictive factor for malignancy in SPT.
Despite advances in the management of necrotizing pancreatitis, open necrosectomy remains an important management option for necrotizing pancreatitis, and patients undergoing necrosectomy suffer significant morbidity and mortality. The aim of this study was to report the outcomes of open necrosectomy from a recent large cohort of patients with necrotizing pancreatitis.
Pancreatic cancer is the fourth leading cause of cancer related deaths in the United States. The prognosis remains dismal with little advance in treatment. Metformin is a drug widely used for the treatment of type II diabetes. Recent epidemiologic data revealed that oral administration of metformin is associated with a reduced risk of pancreatic cancer, suggesting its potential as a novel drug for this disease. Many studies have demonstrated the in vitro anticancer action of metformin, but the typically used concentrations were much higher than the in vivo plasma and tissue concentrations achieved with recommended therapeutic doses of metformin, and low concentrations of metformin had little effect on the proliferation of pancreatic cancer cells. We examined the effect of low concentrations of metformin on different subpopulations of pancreatic cancer cells and found that these selectively inhibited the proliferation of CD133? but not CD24?CD44?ESA? cells. We also examined the effect of low concentrations of metformin on cell invasion and in vivo tumor formation, demonstrating in vitro and in vivo anticancer action. Metformin was associated with a reduction of phospho-Erk and phospho-mTOR independent of Akt and AMPK phosphorylation. CD133? pancreatic cancer cells are considered to be cancer stem cells that contribute to recurrence, metastasis and resistance to adjuvant therapies in pancreatic cancer. Our results provide a basis for combination of metformin with current therapies to improve the prognosis of this disease.
The polycomb protein Bmi-1 plays oncogenic roles in various cancers. Here we aimed to investigate the contribution of Bmi-1 on the malignant behaviors of pancreatic cancer such as chemoresistance, invasion and tumorigenesis.
Pancreatic cancer is one of the most lethal malignancies with poor prognosis. Previously, we found that a subpopulation of cancer stem cells (CSCs) in the Panc-1 pancreatic cancer cell line could propagate to form spheres. Here we characterized the malignant phenotypes of the pancreatic cancer stem CD44+/CD24+ cells, which were enriched under sphere forming conditions as analyzed by flow cytometry. These cells demonstrated increased resistance to gemcitabine and increased migration ability. Moreover, these cells exhibited epithelial to mesenchymal transition characterized by a decreased level of the epithelial marker E-cadherin and an increased level of the mesenchymal marker vimentin. Notably, abnormal expression of Bmi-1, ABCG2, Cyclin D1 and p16 were found in Panc-1 CSCs. Our results suggest that targeted inhibition of CSCs represents a novel therapeutic approach to overcome chemoresistance and metastasis of pancreatic cancer.
To investigate resveratrol, one of the food derived polyphenols that might be partially responsible for the beneficial effect on cancer, the in vitro antitumor activity of resveratrol against pancreatic cancer cell lines (PANC-1, BxPC-3 and AsPC-1) was examined, together with the mechanisms involved. The effects of resveratrol on the growth inhibition, apoptosis and cell cycle were assayed. The activity of caspases and the expression of Bcl-2, Bcl-xL, XIAP and Bax protein were detected. The results showed that resveratrol inhibited the proliferation of pancreatic cancer cells in a dose- and time-dependent manner. Resveratrol inhibited the cell growth of PANC-1, BxPC-3 and AsPC-1 cells with IC(50) values of 78.3 ± 9.6 ?mol/L, 76.1 ± 7.8 ?mol/L and 123.1 ± 6.5 ?mol/L at 48 h, respectively. Incubation of pancreatic cancer cells with resveratrol resulted in cell apoptosis and cell cycle arrests. Resveratrol induced activation of caspases. Simultaneously, resveratrol regulated the expression of the antiapoptotic proteins Bcl-2, Bcl-xL and XIAP and the proapoptotic protein Bax. PANC-1 and BxPC-3 cells were more chemosensitive to resveratrol than AsPC-1 cells. In conclusion, resveratrol inhibited the proliferation of pancreatic cancer cells by inducing apoptotic cell death. There was different sensitivity to resveratrol in different pancreatic cancer cell lines.
This study examined whether insulin-stimulated hypoxia-inducible factor 1alpha (HIF-1alpha) expression plays a crucial role in promoting the proliferative vitality and invasive capability in human pancreatic cancer cells. PANC-1 cells were divided into three groups: Control group, insulin group and insulin+YC-1 (a pharmacological inhibitor of HIF-1alpha) group in terms of different treatments. Cells in the insulin group or insulin+YC-1 group were treated with insulin (0.1, 1, 10 and 100 nmol/L) alone or combined with 3-(5-hydroxymethyl-2-furyl)-1-benzyl indazole (YC-1, 0.1, 1, 10 and 100 micromol/L). HIF-1alpha mRNA and protein expression in PANC-1 cells was determined by real-time RT-PCR and Western blotting respectively. Cell proliferation and invasion were measured by using growth curve and invasion assay, respectively. Western blot analysis demonstrated that insulin dose-dependently increased the HIF-1alpha protein expression, and YC-1 could dose-dependently block this effect. However, neither insulin nor YC-1 altered HIF-1alpha mRNA levels in PANC-1 cells. Moreover, insulin could enhance the proliferation and invasion of PANC-1 cells, while YC-1 could weaken this effect. It was concluded that the malignant proliferation and local invasion of pancreatic cancer cells may be related to high-insulin microenvironment. The tumor biological behavior change resulting from high-insulin microenvironment may be associated with the increased expression of HIF-1alpha protein.
Some observations have suggested that extensive culture of adult stem cells can lead to malignant transformation. Therefore, it has become commonplace to use stem cells undergoing little or no in vitro culture to circumvent this presumptive limitation. Recently, a detailed study documented that malignant transformation of adult neural stem cells can be avoided under suitable culture conditions. Here, we report the first demonstration that murine bone marrow-derived mesenchymal stem cells (bMSCs) were propagated in vitro for up to 50 passages without any transformation sign under suitable conditions. However, it must be noted that although the long-term cultured bMSCs were comparable with short-term cultured bMSCs in proliferation, migration and invasion, they lost their pluripotent potential. The long-term cultured bMSCs could only differentiate into adipocytes but not into osteocytes or chondrocytes. In conclusion, murine bMSCs can be propagated in vitro for up to 50 passages with no malignant transformation sign under suitable conditions, but how to sustain their pluripotent potential requires further investigation.
Collagen is the most prominent protein in the human body, making up 30% of the total protein content. Quantitative studies have shown structural differences between collagen fibers of the normal and diseased tissues, due to the remodeling of the extracellular matrix during the pathological process. The dominant orientation, which is an important characteristic of collagen fibers, has not been taken into consideration for quantitative collagen analysis. Based on the conventional gray level co-occurrence matrix (GLCM) method, the authors proposed the orientation-dependent GLCM (OD-GLCM) method by estimating the dominant orientation of collagen fibers. The authors validated the utility of the OD-GLCM method on second harmonic generation (SHG) microscopic images of tendons from rats with different ages. Compared with conventional GLCM method, the authors method has not only improved the discrimination between different tissues but also provided additional texture information of the orderliness of collagen fibers and the fiber size. The OD-GLCM method was further applied to the differentiation of the preliminary SHG images of normal and cancerous human pancreatic tissues. The combination of SHG microscopy and the OD-GLCM method might be helpful for the evaluation of diseases marked with abnormal collagen morphology.
Bone marrow-derived mesenchymal stem cells (bMSCs) contribute to tissue repair and regeneration. Cell fusion between somatic cells and bMSCs to form hybrid cells may have an important role in tissue repair through the subsequent reprogramming of the somatic cell nucleus. Few studies have assessed the mesenchymal characteristics of fusion-induced hybrid cells and their survival mechanisms. In this study, we investigated the effect of cell fusion on the biological characteristics of pancreatic ductal cells (PDCs) and on the survival mechanism of hybrid cells. To this end, we generated mouse-mouse hybrid cells in vitro by polyethylene glycol-mediated fusion of primary mouse bMSCs with primary mouse PDCs. Hybrid cells showed an enhanced capacity for proliferation and self-renewal compared with PDCs. No PDC had the capacity for anchorage-independent growth or invasion into Matrigel, but some hybrid cells were able to form colonies in soft agar and invade Matrigel. Expression of the tumor suppressor protein p53, which initiates apoptosis, was detected in hybrid cells but not in PDCs or bMSCs. However, the p53 deacetylase, sirtuin 1 (SIRT1), was also detected in hybrid cells, and the level of acetylated p53, the active form, was low. The addition of nicotinamide (Nam) inhibited the deacetylation activity of SIRT1 on p53 and induced cell apoptosis in hybrid cells. This study demonstrated that PDCs could obtain high proliferation rates, self-renewal capabilities, and mesenchymal characteristics by fusion with bMSCs. SIRT1 expression in the hybrid cells attenuated their apoptosis.
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