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. Author manuscript; available in PMC: 2019 Jul 15.
Published in final edited form as: Clin Cancer Res. 2018 Oct 15;25(2):629–640. doi: 10.1158/1078-0432.CCR-18-1033

Figure 2. Effects of SGK1-induced differentiation on colon cancer cell proliferation and tumorigenicity.

Figure 2

A. The column chart displays ratios of HT29-SGK1 and LS174T-SGK1 proliferation (measured by tetrazolium compound assay) and apoptosis (basal and upon osmotic stress stimulation) 24 hours after removal of doxycycline, relative to controls with doxycycline maintained. Proliferation and apoptosis were significantly reduced in SGK1-expressing cells (all t-test p-values <0.05, experiments done in triplicate).

B. Representative images show colonospheres formed by untransduced, GFP-transduced (GFP) and SGK1-transduced (SGK1) cells for HT29 and LS174T colorectal cancer cell lines. Images were acquired following 10 days of cell culturing conditions that favour stem cell growth and colonosphere formation. The column charts represent absorbance measurements from an endpoint tetrazolium compound assay (day 10), showing decreased proliferation rates of the stem cell populations upon re-expression of SGK1 (t-test p-values<0.01 in all cases; experiments done in triplicate).

C. The column charts show numbers of colonies formed in soft agar by untreated, GFP-transduced (GFP) or SGK1-transduced (SGK1) cells. Results are an average of three experiments (t-test p-values<0.005 in all cases). Below the chart are representative images displaying macroscopic differences between untreated controls or SGK1-transduced cells.

D. Cellular migration is reduced on SGK1 re-expression (reduction in migration rate 43% for LS174T and 62% for HT29; t-test, p<0.01 and p<0.0001 respectively.

E. SGK1 mRNA expressions and CRC baseline migration rate. There is a significant negative correlation (Pearson correlation=0.68, p=0.02) between native SGK1 expression levels and migration in a panel of CRC lines (COLO205, GP2D, HCT116, HT29, LS174T, LS180, SNU-C4, SW1222, SW48, SW480, T84). Note that higher deltaCt corresponds to lower SGK1 expression.