Fig. 5. Effect of SB and IR on expression of DNA repair and pro-survival signaling proteins in EGFR-knockdown PCa cells. At ~70% confluency, pLKO.1 and EGFR knockdown DU145 cells were treated with SB (25 µM) and/or IR (5 Gy) for 12 hours and cells were harvested and whole cell lysate was prepared. (A) Whole cell lysates were analyzed for the protein expression of EGFR, DNA-PK, Rad51, Ku70, Ku80, p-p53 and p53 by immunoblotting. β-actin was used as a loading control. (B) Cell lysates were analyzed for p-Akt, Akt, p-STAT3, STAT3, p-ERK1/2, ERK and β-actin proteins. Bands were quantitated using Image J software and represented as fold change with respect to control below each respective band. All the experiments were repeated at least three times. SB, silibinin; IR, ionizing radiation; EGFR, EGF receptor; PCa, prostate cancer; DNA-PK, DNA-dependent protein kinase; p-Akt, phospho-Akt; ERK1/2, extracellular signal-regulated kinases1/2; p-ERK1/2, phospho-extracellular signal-regulated kinases1/2; ND, not detected.

© J Cancer Prev