MicroRNA-17-92 gene promotes renewal and proliferation of gastric cancer stem cells / 中国组织工程研究

ABSTRACT

BACKGROUND:Studies have shown that microRNAs (miRNAs) have moderating effect on the renewal and differentiation of cancer stem cels. However, there is no complete understanding on the effect of microRNA-17-92 gene on gastric cancer stem cel renewal and proliferation. OBJECTIVE:To explore the effect of miRNA-17-92 in promoting self-renewal and proliferation of gastric cancer stem cels. METHODS:(1) The gradualy reduced miRNAs during gastric cancer stem cel self-renewal were investigated using miRNA array based on RNAs from differentiated and adherent cels. (2) The miRNA-17-92 was constructed and transfected to gastric cancer stem cels. (3) The effects of miRNA-17-92 on the self-renewal of gastric cancer stem cels were studied by tumor sphere assayin vitro. (4) The effects of miRNA-17-92 on the proliferation of gastric cancer stem cels were investigated by MTT assay and colony formation assay. RESULTS AND CONCLUSION:(1) miR-19b/20a/92a expression gradualy reduced in the adhesion and differentiation of gastric cancer stem cels. (2) The expression of lentivirus carrying miRNA-17-19 gene in MKN28 cels and CD44-/EpCAM- cels were significantly increased; transient transfection of pre-miR-19b/20a/92a increased the expression of CD44-/EpCAM- and MKN28 miRNA, transient transfection of pre-miR-19b/20a/92a antagonists reduced the expression of SGC7901 and CD44+/EpCAM+ miRNA; overexpression of lenti-miR-19b/20a/92a significantly increased the ability of gastric cels to form tumor spheres; chemotherapy drugs prolonged the survival time of lenti-miR-19b/20a/92a-infected cels; transient transfection of pre-miR-19b/20a/92a significantly increased the number of CD44+/EpCAM+ cels, but transfection of pre-miR-19b/20a/92a antagonist reduced the number of CD44+/EpCAM+ cels. (3) MTT proliferation assay showed that gastric cancer cel proliferation rate in miR-19b/20a/92a stably expressing group was faster than that in the control group. Transient transfection of miR-19b/20a/92a precursor accelerated the growth rate of gastric cancer cels, and transient transfection of its antagonist slowed down the growth rate of gastric cancer cels. Colony formation assay showed that transient transfection of miR-19b/20a/92a precursor significantly increased the colony formation number as compared with the control group; transient transfection of miR-19b/20a/92a antagonist reduced the colony formation as compared with the control group. These findings indicate that miR-19b/20a/92a gene presents with continuous deletion in gastric cancer stem cel differentiation process, and miRNA-17-92 gene can promote the renewal and proliferation of gastric cancer stem cels.