Figure 5.

C4-2B metastatic CRPC cells upregulate autophagy as a protective mechanism against combination simvastatin and metformin treatment. (a) Transmission electron microscopy pictures of untreated and combination 4 μM simvastatin (SIM) and 2 mM metformin (MET)-treated C4-2B3 and C4-2B4 cells at 72 h. Black arrows show double-membrane degradative (i.e., lysosome associated with vesicle) and lucent autophagic vesicles. White arrows show potentially mitoptotic mitochondria. Scale bar noted on images. (b) Percentage cell viability (mean±S.D.) by methylene blue in C4-2B3 and C4-2B4 cells following treatment with combination 4 μM SIM and 2 mM MET±10 μM chloroquine (CQ) lysosomal inhibitor for 48−96 h, n=3 per group. **P<0.01, ***P<0.001, and NS=no significant difference between treatment groups of SIM+MET in presence or absence of CQ, as determined by the two-tailed Student's t-test