Analysis of human telomerase reverse transcriptase (hTERT) downregulation effect in MCF7 and MDA-MB-231 cells. (A) Representative images of GFP expression in the MCF7 and MDA-MB-231 cells transduced with pLV-THEM-shTERT (shRNA hTERT) and pLV-THEM-shRNA (shRNA Control); magnification 40×, scale bars 100 μm; (B) hTERT gene expression at the protein level, semi-quantitative analysis of Western blot results using Image Studio Lite software. GAPDH was used as loading control. (C) Relative hTERT gene expression at the transcriptional level measured by qPCR. (D) Relative telomerase activity determined by telomeric repeat amplification protocol (TRAP) assay. (E) Relative telomere length measured by qPCR. shRNA Control, cells transduced with lentiviral vectors containing scramble shRNA; shRNA hTERT, cells transduced with lentiviral vectors containing shRNA against hTERT. 0.1 μM doxorubicin (DOX); 8h treatment. Data are presented as the mean ± standard deviation. (*) the symbol for p < 0.05; (**) for p < 0.01, with comparison to shRNA Control.