Fig 1. STK4 expression is down regulated in HPV+ cervical cancer.

A) Representative western blot analysis of a panel of HPV- and HPV+ cervical cancer cell lines for components of the Hippo pathway. GAPDH served as a loading control. B) Densitometry analysis of STK4 expression in A from four independent experiments. SiHa p = 0.0087 and CaSKi p = 0.0044; SW756 p = 0.0052 and HeLa p = 0.0018; C33A p = 0.44 when compared to NHK. C) Representative western blot from cytology samples of CIN lesions of increasing grade analysed for STK4 expression. GAPDH served as a loading control. D) Scatter plot of densitometry analysis of a panel of cytology samples. Twenty samples from each clinical grade (Neg, CIN 1–3) were analysed by western blot and densitometry analysis was performed for STK4 expression. CIN1 not significant; CIN2 p = 0.001; CIN3 p = 0.001 when compared with neg samples. E) Representative immunofluorescence analysis of tissue sections from cervical lesions representing LSIL and HSIL. Sections were stained for STK4 expression (green) and nuclei were visualised using DAPI (blue). Images were acquired using identical exposure times. Scale bar, 20 μm. F-G) Representative western blot of proteasome inhibitor MG132 (F) and lysosome inhibitor chloroquine (G) dose response in HeLa and CaSKi cells. Cell lysates were probed for the expression of STK4. GAPDH was used as a loading control (N = 3). H) qPCR analysis of STK4 transcript levels in a panel of HPV- and HPV+ cervical cancer cell lines. U6 expression was used as a loading control (n = 3). SiHa p = 0.01 and CaSKi p = 0.004; SW756 p = 0.001 and HeLa p = 0.05; C33A p = 0.12 when compared to NHK. I) qPCR analysis of STK4 transcript levels from different CIN grades (n = 5 from each grade). U6 expression was used as a control. CIN1 not significant; CIN2 p = 4.6x10^-7; CIN3 p = 1.1x10^-5 when compared to neg samples. Error bars represent the mean +/- standard deviation. *P<0.05, **P<0.01, ***P<0.001 (Student’s t-test).