Pancreatic cancer is aggressive; 80-90 % of pancreatic cancer patients have already developed metastatic cancer at the time of diagnosis. Inflammation has been shown to facilitate pancreatic cancer migration. The toll-like receptors (TLRs) pathway is an important inflammatory signal transduction pathway. However, the mechanism of inflammation pathway to induce pancreatic cancer migration is unclear.
Expression of the transmembrane-4-L-six-family-1 (TM4SF1) is high in human pancreatic cancer cells, but the underlying mechanism remains unclear. In this study, we aimed to identify and characterize microRNAs that regulate TM4SF1 expression in PC cells. Western blot analysis and quantitative polymerase chain reaction were used to detect TM4SF1 and hsa-miR-141 levels in four PC cell lines. SW1990 and BxPc-3 cells were transfected with the inhibitor miR-141, the inhibitor negative control, the miR-141 mimic and the mimic negative control; and cell invasion, migration, proliferation, cell cycle progression and apoptosis were detected by Transwell, MTT and flow cytometry assays, respectively. The miR-141 levels negatively correlated with the TM4SF1 protein levels in PC cells. The TM4SF1 protein levels were lower in the 141M group but higher in the 141I group, although the TM4SF1 mRNA levels had no significant changes, compared to the negative controls. Luciferase assays demonstrated that hsa-miR-141 directly targeted the 3-untranslated region of the TM4SF1 gene. In addition, miR-141 downregulated TM4SF1 expression to inhibit invasion and migration of PC cells but had no effects on cell proliferation, cell cycle progression or apoptosis. TM4SF1 is a direct target of miR-141. Our findings that TM4SF1 expression was inhibited by miR-141 provide new insights into the oncogenic mechanism of TM4SF1 and suggest that miR-141 represents a novel molecular target for PC therapy.
MicroRNAs have emerged as crucial regulators of tumorigenesis. However, the mechanism by which miR?203 is involved in the pathogenesis of pancreatic cancer (PC) remains elusive. In the present study, PC cell lines were used as an experimental model to investigate the expression and functional role of miR?203 in PC. miR?203 mimic virus, miRNA negative control virus and Survivin shRNA virus were transfected into the PC cell line, CFPAC?1. mRNA and protein levels of Survivin were detected using qPCR and western blot analysis. Proliferation, apoptosis and cell cycle profiles were detected by an MTT assay and flow cytometry. Female BALB/cA?nu nude mice were used to validate the role of miR?203 in vivo. The protein levels of Survivin were found to negatively correlate with miR?203 levels in four PC cell lines. A luciferase assay revealed that Survivin was a direct target of miR?203. Transfection with miR?203 mimic inhibited CFPAC?1 cell proliferation and induced apoptosis and G1 phase cell cycle arrest, similar to knockdown of Survivin. In the in vivo nude mouse model, the downregulation of Survivin by knockdown of Survivin or transfection with miR?203 mimic inhibited tumor growth. Results of the current study indicate that miR?203 regulates the proliferation, apoptosis and cell cycle progression of PC cells by targeting Survivin.
Cerebral ischemia is a major cause of adult disability and death worldwide. Evidence suggests that Bax-dependent initiation and activation of intrinsic apoptotic pathways contribute to ischemic brain injury. We investigated the Bax-inhibiting peptide VPALR, designed from the rat Ku70-Bax inhibiting domain, on the apoptotic neuronal cell death and behavioral deficits following global cerebral ischemia. The pentapeptide was infused into the left lateral ventricle of the rat brain by intracerebroventricular (i.c.v.) injection 1 h after cerebral ischemia, and results showed that it highly permeated hippocampal neurons and bound to Bax protein in vivo. Post-treatment with VPALR reduced the delayed neuronal damage by approximately 78% compared to the non-treated ischemic control and scrambled peptide-treated rats. TUNEL analysis revealed that VPALR markedly reduced the ischemia-induced increase in apoptotic neuronal death in rat hippocampal CA1 region. VPALR post-treatment also significantly attenuated Bax activation and its mitochondrial translocation as compared with scrambled peptide-treated animals. Concomitantly, Bax-inhibiting peptide-treated rats showed reduced cytochrome c release from mitochondria to cytosol and reduced caspase-3 activation in response to cerebral ischemia, indicating that activation of the intrinsic apoptotic pathway was reduced. Furthermore, Bax-inhibiting peptide improved spatial learning and memory performance in the Morris water maze, which was seriously affected by global cerebral ischemia. In conclusion, Bax inhibition by cell-permeable pentapeptides reduced apoptotic neuronal injury in the hippocampal CA1 region and behavioral deficits following global ischemia. These results suggest that Bax is a potential target for pharmacological neuroprotection and that Bax-inhibiting peptide may be a promising neuroprotective strategy for cerebral ischemia.
To investigate spatial patterns of intrinsic neural activity of depressed patients with vascular risk factors using resting-state functional magnetic resonance imaging (fMRI) and to examine the relationship between regional activity abnormalities and symptom severity factor, we analyzed spatial patterns of spontaneous brain activity in 19 depressed patients with vascular risk factors and 18 healthy subjects. Intrinsic brain activity was measured by the amplitude of low-frequency fluctuations (ALFF) of the resting-state blood oxygen level dependent signal. Depressed patients with vascular risk factors showed decrease in ALFF in the limbic-cortical-striatal-pallidal-thalamic circuit. Specifically, the altered ALFF values (i.e., left insula and right superior frontal gyrus) were significantly correlated with depression severity in the depressed group. In addition, higher ALFF values in the right middle temporal gyrus and right superior temporal gyrus were observed in depressed patients with vascular risk factors. Our findings reveal distinct functional patterns of abnormal brain activity in depressed patients with vascular risk factors and have implications for the understanding of the pathophysiology of this understudied population.
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