TMPO-AS1-dependent ESR1 mRNA stabilization is important for cell cycle progression. (A and B) RNA polymerase II (Pol II) occupancy on MCM6, CDC6, and MAD2L1 promoter regions in MCF7 (A) and T47D (B) cells analyzed by ChIP assay. Data were normalized by input DNA and are presented as means ± SD (n = 3). (C) Viability of MCF-7 cells stably overexpressing TMPO-AS1 treated with the indicated siRNAs in charcoal-stripped FBS (cFBS)-containing medium, analyzed by DNA assay (n = 5). (D) ESR1, MCM6, CDC6, and MAD2L1 mRNA levels in MCF-7 cells stably overexpressing TMPO-AS1 treated with the indicated siRNAs in cFBS-containing medium. Data are presented as mean fold changes ± SD versus levels for siControl (n = 3). (E) Viability of MCF-7 cells stably overexpressing TMPO-AS1, treated with E2 (10−13 M) or left untreated, in cFBS-containing medium after 3 days of pretreatment with cFBS, analyzed by DNA assay (n = 5). (F) Exogenous caERα mRNA levels in MCF-7 cells stably overexpressing caERα treated with the indicated siRNAs. Data are presented as mean fold changes ± SD versus levels for siControl (n = 3). (G) Viability of control and TMPO-AS1 stably overexpressing MCF-7 cells on day 5 after siRNA treatment, analyzed by DNA assay. Values are presented as means ± SD versus levels for siControl in each cell type (n = 5). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not significant.