Figure 3.

LDLR levels are influenced by miR-92b processing by APE1. (a) HeLa cells with WT APE1 and APE1 KD had their total RNA purified and their levels of LDLR mRNA transcripts quantified by qRT-PCR following reverse transcription. LDLR mRNA transcripts were normalized to GAPDH. (b) HeLa cells incubated with compound #3 (20 µM) or E3330 (100 µM) for 24 h or HeLa cells with siRNA-mediated APE1 KD had their levels of LDLR mRNA quantified by qRT-PCR following reverse transcription. LDLR mRNA transcripts were normalized to GAPDH. (c, d) HeLa cells with APE1 KD had their total levels of LDLR, PTEN, and p-Akt/Akt quantified by WB, and normalized to tubulin. Data are represented as means ± SEMs. *p < 0.05, **p < 0.01. (e) IHC analysis of LDLR and APE1 protein levels in human cervical cancer biopsy samples (n = 50), exemplified by typical IHC images. LDLR protein has higher in tumor biopsies with lower APE1 protein levels, and conversely lower in biopsies with greater APE1 levels. (f) Semi-quantification of LDLR scores (0, 1, 2, or 3) expressed as a percentage within each category of APE1 expression (0, 1, 2, or 3) represented as bar chart. Scoring was assessed by the following criteria: (i) score of 0: no protein expression in cancer cells, (ii) score of 1: faint protein expression in <10% of cancer cells, (iii) score of 2: faint to intermediate expression in >10% of cancer cells, and (iv) score of 3: strong expression in >10% of cancer cells. (g) miR-to-pri-miR ratios for miR-92b for each APE1 score level.

Data are represented as means ± SEMs. *p < 0.05, **p < 0.01.

APE1, apurinic/apyrimidinic endodeoxyribonuclease 1; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; IHC, immunohistochemistry; KD, knockdown; LDLR, low-density lipoprotein receptor; NE, no cell extract, NT, nontreated cells; PTEN, phosphatase and tensin homolog; qRT-PCR, quantitative reverse transcription polymerase chain reaction; SEM, standard error of the mean; WB, western blot; WT, wild type.