Inhibition of p38 activity reverses claudin-6 induced cell apoptosis, invasion, and migration / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Claudin-6 is a protein component of tight junctions and its expression could downregulate the malignant phenotype of breast carcinoma. Here we investigated the mechanisms of claudin-6 induced human MCF-7 breast cancer cells apoptosis, invasion, and migration.</p><p><b>METHODS</b>Terminal deoxyribonucleotide transferase-mediated nick-end labeling assay and Annexin-V/PI double stain assay were carried out to evaluate apoptosis. Inhibitors of each pathway were used to inactivate the signaling pathways. The expression of claudin-6 and phosphate p38, Erk 1/2 and Akt protein levels was confirmed by Western blotting analysis. Invasive and migratory traits of claudin-6 expressing cells were determined by Boyden chamber invasion assay and monolayer wound-healing assay.</p><p><b>RESULTS</b>Cells with high-level expression of claudin-6 had a higher rate of apoptosis than control cells. Western blotting assay showed that by contrast to control groups, p38 pathways were more activated in claudin-6 expressing cells. However, after inhibitor SB203580 treatment, the activation status could be significantly counteracted. Furthermore, by applying inhibitors to the apoptotic rate, invasive and migratory traits were also recovered in cells with claudin-6 expression.</p><p><b>CONCLUSION</b>Claudin-6 may function through p38 mitogen-activated protein kinase pathway, of which inhibition may reverse claudin-6-induced cell apoptosis, invasion, and migration.</p>

Effects of 17β-estradiol on proliferation and migration of MCF-7 cell by regulating expression of claudin-6 / 中华病理学杂志

<p><b>OBJECTIVE</b>To explore the role of estrogen in the regulation of the expression of claudin-6 and biological behavior in MCF-7 cells.</p><p><b>METHODS</b>RT-PCR and immunocytochemistry were conducted to analyze the expression and localization of claudin-6 in MCF-7 cells treated with 17β-estradiol. CCK-8 kit assay and Scratch Test were conducted to analyze the capability of proliferation and migration of 17β-estradiol treated MCF-7 cells.</p><p><b>RESULTS</b>RT-PCR analysis and immunocytochemistry showed that 17β-estradiol induced a concentration-and time-dependent effect on claudin-6. At 5 nmol/L and at 24 h, 17β-estradiol treatment led to an increased level of claudin-6, which was located in the membrane of MCF-7 cells. CCK-8 analysis showed a significant decrease in the capability of proliferation of MCF-7 cells compared with the control group (P < 0.05). Cells Scratch Test showed decreased migration capability of MCF-7 cells compared with the control group (P > 0.05).</p><p><b>CONCLUSIONS</b>17β-E2 might regulate the expression of claudin-6 and inhibit the proliferation and migration of MCF-7 cells. The inhibitory effects of 17β-E2 on growth and migration of MCF-7 cells may be mediated by claudin-6 expression regulation.</p>