In vitro effect of long interspersed nucleotide acids element-1 ORF-1p on estrogen receptorα of positive human breast cancer cells

Objective To study the effect of long interspersed nucleotide acids element-1(LINE-1) ORF-1p on proliferation of estrogen receptor α(ERα) positive human breast cancer ZR75-1 cells and its possible mechanism. Methods LINE-1 ORF-1 expression vector siRNA or empty vector,was transfected into ERα positive ZR75-1 cells with Lipofectin 2000.Effect of LINE-1 ORF-1p on proliferation of ERα positive ZR75-1 cells and transcriptional activity of ERα was detected by MTT and luciferase assay,respectively. Results MTT assay showed that LINE-1 Flag-ORF-1p promoted the proliferation of ERα positive ZR75-1 cells(P=0.018) while LINE-1 ORF-1p expression vector siRNA inhibited the proliferation of ZR75-1 cells(P=0.022) with an in vitro inhibition rate of 25.51% and 64.29% for E2-and E2+,respectively(P<0.05).LINE-1 Flag-ORF-1 increased the transcriptional activity of ERα(P=0.05) while LINE-1 ORF-1p expression vector siRNA reduced the transcriptional activity of ERα(P=0.015). Conclusion LINE-1 ORF-1p promotes the proliferation of ZR75-1 cells by increasing the transcription activity of ERα.