ABSTRACT
OBJECTIVE: The mechanism underlying the therapeutic effects of combi-molecule JDF12 on prostate cancer (PCa) DU145 cells remains still unclear. This study aimed to investigate the proteomic profile after JDF12 treatment in DU145 cells by comparing with that in Iressa treated cells and untreated cells. METHODS: MTT was used to evaluate drug cytotoxicity, DAPI staining was done to assess apoptosis of cells, and flow cytometry was used to analyze cell cycle. iTRAQ and qPCR were employed to obtain the proteomic profiles of JDF12 treated, Iressa treated, and untreated DU145 cells, and validate the expression of selected differentially expressed proteins, respectively. RESULTS: JDF12 could significantly inhibit the proliferation and increase the apoptosis of DU145 cells when compared with Iressa or blank group. In total, 5071 proteins were obtained, out of which, 42, including 21 up-regulated and 21 down-regulated proteins, were differentially expressed in JDF12 group when compared with Iressa and blank groups. The up-regulated proteins were mainly involved in DNA damage/repair and energy metabolism; while the down-regulated proteins were mainly associated with cell apoptosis. qPCR confirmed the expression of several biologically important proteins in DU145 cells after JDF12 treatment. CONCLUSION: The molecular mechanisms of DNA alkylating agents on PCa therapy that with the assistant of EGFR-blocker were revealed on proteomic level, which may increase the possible applications of DNA alkylating agents and JDF12 on PCa therapy.
ABSTRACT
OBJECTIVE: This study aimed to investigate the biological effects of "combi-targeting" JDF12 and its effect on the DNA repair pathway in hormone-refractory prostate cancer (HRPC). METHODS: HRPC cell lines (PC3 cells and VCap cells) were treated with JDF12 at different concentrations, and SRB method was employed to detect the proliferation of HRPC cells; Annexin V-FITC kit was used to detect the apoptosis of PC3 cells; Alkaline comet assay was performed to detect DNA damage; Western blot assay was done to detect the expressions of autophosphorylated EGFR, XRCC1 and ERCC1 (later two are proteins in DNA repair pathway); the anti-tumor effect was evaluated in nude mice inoculated with PC3 cells. RESULTS: JDF12 could inhibit the proliferation of PC3 cells and VCap cells in a concentration dependent manner (IC50: 14.04 ± 1.22 for PC3 and 15.57 ± 1.13 for VCap) and significantly increase the apoptotic cells as compared to those treated with mitozolomide or iressa alone. In PC3 cells, JDF12 induced DNA damage and also inhibited the expressions of phosphorylated EGFR, XRCC1 and ERCC1 in a concentration dependent manner. Moreover, JDF12 markedly inhibited tumor growth in nude mice. CONCLUSION: The novel "combi-targeting" JDF12 may exert more potent anti-proliferative effect as compared to mitozolomide or iressa alone, and the inhibitory effect on the EGFR signaling pathway and down-regulated XRCC1 and ERCC1 expressions may be ascribed to the JDF12 induced DNA damage.