miR-542-5p down-regulates IEC-6 cell proliferation induced by sphingosine-1-phosphate / 中国病理生理杂志

ABSTRACT

AIM: To observe the effects of miR-542-5p on the proliferation of rat small intestine crypt epithe-lial IEC-6 cells induced by sphingosine-1-phosphate (S1P).METHODS: Two IEC-6 cell lines (SphK1-IEC-C1 and SphK1-IEC-C2) were established, which expressed sphingosine kinase-1 (SphK1) stably.Radioactive tracer was used to detect SphK1 activity and S1P secretion.The cell proliferation was observed by cell counting and described by drawing growth curve, and the cell cycle analysis was carried out by flow cytometry.The level of miR-542-5p was evaluated by RT-qPCR.RESULTS: Compared with control vector cells without SphK1 cDNA, both SphK1-IEC-C1 and SphK1-IEC-C2 cell lines showed that Sphk1 was elevated, both intracellular and extracellular S1P increased dramatically, the rate of cell growth was faster, the percentage of the cells in S phase increased, and miR-542-5p expression decreased.S1P (0.5~10 μmol/L) led to the decrease in miR-542-5p expression.On the contrary, SphK1 silencing resulted in the increase in miR-542-5p expression in the IEC-6 cells.The miR-542-5p was elevated in SphK1-IEC-C1 cells and SphK1-IEC-C2 cells, which caused the decrease in the percentage of the cells in S phase.The cell growth rate in the above-mentioned 2 cell lines decreased compared with negative control group.CONCLUSION: In IEC-6 cells, S1P promotes proliferation by inhibiting miR-542-5p expression, which induces the cell cycle transferring from G1 phase to S phase.