关键词: RP11?321G12.1, 乳腺癌, 细胞周期, 长链非编码RNA

Abstract: ［Abstract］ Objective To study the function and mechanism of estrogen receptor?regulated long non?coding RNA RP11-321G12.1 in breast cancer. Methods In the previous study，estrogen receptor-regulated long non?coding RNAs were screened by bioinformatics analysis. In this study，after silencing RP11?321G12.1 by siRNA in ER positive breast cancer cell lines MCF7 and T47D，the effect of RP11? 321G12.1 on cell proliferation and cell cycle was investigated using plate colony formation assay and flow cytometry. The molecular mechanisms involved in RP11?321G12.1 in breast cancer were studied by q?PCR and western blot. Results Silencing of RP11?321G12.1 inhibited the proliferation of MCF7（P= 0.003）and T47D（P=0.001）；it also inhibited the cell cycle，showing as an increase in the ratio of G1 phase cells and a decrease in the ratio of S? phase cells. In the Hu-blocked release assay in T47D cell line，it was found that RP11-321G12.1 was positively correlated with the cell cycle G1 phase （P= 0.039）. Western blot experiments showed that silencing of RP11-321G12.1 can result a decrease inpositive breast cancer. When the ER-regulated lncRNA RP11-321G12.1 is silenced，the cell cycle progression can be inhibited by down-regulating the protein expression levels of the cell cycle-related proteins Cyclin D1 and Cyclin E2，so that the ratio of G1 phase cells is increased and the ratio of S phase cells is decreased. Cell proliferation was significantly inhibited.

Key words: long non?coding RNA, cell cycle, breast cancer, RP11?321G12.1