SOX8 Knockdown Overcomes Enzalutamide Resistance in Castration-Resistant Prostate Cancer by Inhibiting the Notch Signaling Pathway

Figure 5

Notch4 knockdown rescued the proliferation, invasion, metastasis, and drug resistance caused by the overexpression of SOX8 and SOX8-regulated Notch signaling through β-catenin protein. (a) The viability of LNCaP cells was measured by a CCK-8 assay after knocking down Notch4 using adenoviruses in cells that overexpressed SOX8. (b) Colony-forming efficiency of SOX8-overexpressing Notch4 knocked down LNCaP cells after 10 days of culture. The Transwell assay was performed to examine the invasive ability of LNCaP cells following SOX8 overexpression and Notch4 knockdown (magnification, ×400). (c) Cyclin D1, Cyclin E1, BAK1, and Bcl-2 were detected using Western blot assay; GAPDH served as a loading control. (d) LNCaP cells were exposed to increasing concentrations of enzalutamide (0, 0.3, 0.6, 1.2, 2.4, 3.6, 4.8, 6.0, and 7.2 μM) for 48 h, and the half maximal inhibitory concentration (IC₅₀) was determined by a CCK-8 assay. (e) Enza-R cell was subjected to SOX8 knockdown and/or treatment with AZD2858 (5 nM 24 hours) or PNU74654 (5 nM 24 hours). The expression of SOX8, β-catenin, p-β-catenin, Notch1, and Notch4 was detected by Western blot assay; , GAPDH served as a loading control, .

(a)

(b)

(c)

(d)

(e)