Fig. 2

LncRNA H19 is overexpressed in tamoxifen-resistant cell line and tumor samples and facilitates tamoxifen resistance. a mRNA expression of H19 in 37 breast cancer tissue samples. The data are presented as the mean ± SD; n = 37. The Wilcoxon signed-rank test was used for statistical analysis. b mRNA expression of H19 in MCF7/TAMR cells and parental MCF7 cells. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. c H19 expression statuses in tamoxifen-resistant and tamoxifen-sensitive MCF7 cells were obtained from GSE26459 and GSE28645. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. d MCF7/TAMR cells were stably infected with the shControl (shCtrl) lentiviral vector or the shH19 lentiviral vector. The efficiency of RNA interference-mediated knockdown of target gene expression was determined by qRT-PCR analysis. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. e Representative images of the colony formation assays using MCF7/TAMR cells that stably expressed shCtrl or shH19 under 10 μM tamoxifen treatment. The bar graphs show the quantification of the colony formation assay data. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. f MCF7/TAMR cells were transfected with the siCtrl or the siH19. The efficiency of RNA interference-mediated knockdown of target gene expression was determined by qRT-PCR analysis. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. g Under 10 μM tamoxifen treatment, the viability of MCF7/TAMR cells that transfected with siH19 or shCtrl was analyzed using a CCK-8 assay. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. h MCF7 cells were stably infected with the lentiviral empty vector or the H19 overexpression lentiviral vector. The overexpression efficiency of target gene expression was determined by qRT-PCR analysis. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. i H19-overexpressing MCF7 cells or parental tamoxifen-sensitive MCF7 with empty vector cultured in different concentrations of tamoxifen was analyzed using a CCK-8 assay. The data were then used to calculate the IC50 of each cell line. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. j Cell cycle analysis after knockdown of H19 was conducted using flow cytometry. The data are presented as the mean ± SD of three independent experiments. Student’s t test was used for statistical analysis. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001 compared with the control group