Figure 6. Schematic representation of radiosensitizing effects of a low non-toxic dose of SB in radioresistant DU145 PCa cells.

SB-induced radiosensitization of PCa cells via down-regulating DSBs DNA repair pathways (HR and NHEJ) proteins, Rad51 and DNA-PK, and this effect was further increased in EGFR-deficient cells. Further, SB inhibited pro-survival signaling molecules, ERK1/2, Akt and STAT3 in EGFR-deficient PCa cells exposed to radiation. SB, silibinin; IR, ionizing radiation; PCa, prostate cancer; DSB, double strand break; HR, homologous recombination; NHEJ, non-homologous end joining; DNA-PK, dependent protein kinase; ERK1/2, extracellular signal-regulated kinases1/2; EGFR, EGF receptor.