FIG 5.

Acute DINO expression increases susceptibility to metabolic stress. HPV16-positive CaSki cervical cancer cells transduced with inducible DINO or GFP control vector were each treated with 1 μg/ml doxycycline for 48 h. DINO expression and mRNA levels of the TP53 transcriptional target CDKN1A were determined by qRT-PCR. Expression data are presented in arbitrary units (AU) and are normalized to expression of the RPLP0 housekeeping gene (A, left panel). Concomitant changes in TP53 protein levels were assessed by immunoblotting, with α-tubulin (α-Tub) serving as a loading control. The positions of marker proteins with their apparent molecular weights in kilodaltons (kD) are indicated (A, right panel). GFP- or DINO-expressing CaSki cells were incubated with serum-free medium (B) or grown in normal-serum-containing medium supplemented with the indicated concentrations of metformin or phenformin for 72 h (C), and cell viability was assessed. Graphs represent means ± SEM (n = 3). ***, P < 0.001; **, P < 0.01; *, P < 0.05 (Student’s t test).