Figure 7. LncRNA152 and lncRNA67 regulate the cell cycle and estrogen-dependent signaling in breast cancer cells.

(A) Analysis of lncRNA152 (left) and lncRNA67 (right) expression in MCF-7 cells throughout the cell cycle. Total RNA was isolated from synchronized MCF-7 cells (G0, serum withdrawn; G1/S, double thymidine block/hydroxyurea; G2/M, nocodazole) and analyzed by RT-qPCR. β-actin mRNA was used as an internal control. Each bar represents mean + SEM, n = 3.

(B) siRNA-mediated knockdown of lncRNA152 or lncRNA67 alters cell cycle profile in MCF-7 cells, as assessed by propidium iodide staining and FACS analysis. Asterisks represent significant differences versus the control knockdown (si-Ctrl) (Student’s t-test, p-value < 0.05).

(C) Relative expression of lncRNA152 (left) and lncRNA67 (right) in estrogen-withdrawn MCF-7 cells following a time course of E2 treatment as determined by RT-qPCR. Each bar represents the mean + SEM, n = 3. * p-value < 0.05, Student’s t-test.

(D) Effect of lncRNA152 or lncRNA67 knockdown on the expression of estrogen-regulated genes in MCF-7 cells as determined by RT-qPCR with RPL19 mRNA as an internal control. Forty-eight hours after transfection of the siRNAs, the cells were treated for 3 hours with E2 and total RNA was collected. Each point represents the mean ± SEM, n = 3. Each bar represents the mean + SEM, n = 3.

(E) Effect of lncRNA152 or lncRNA67 knockdown on the growth of MCF-7 cells as determined by crystal violet staining. Twenty-four hours after transfection of the siRNAs, the cells were treated for 3 days with E2 and the cell density was determined. Each point represents the mean ± SEM, n = 3. Asterisks, p-value < 0.05 (**, relative to si-Ctrl; *, relative to –E2).

(F) Model depicting the unique roles of lncRNA152 and lncRNA67 in basal and E2-dependent mitogenic growth.

See also Figure S7.