Basic Research - Cancer(구연) (E-015)

전립선암세포주에서 DRG2의 발현이 도세탁셀 유도사멸에 미치는 영향
울산대학교병원 비뇨기과학교실
김성철, 김송희¹, 이원혁¹, 박명찬, 채종석, 윤지형, 권택민, 박세준, 문경현, 박성찬
Introduction: Docetaxel induces an alternative form of cell death through G2/M arrest. Developmentally regulated GTP-binding protein 2 (DRG2) regulates mitosis by affecting microtubule dynamics. The characteristics of DRG2-regulated mitosis are similar to the responses of cells to chemotherapy drugs such as docetaxel. Therefore, this study aimed to confirm the association between DRG2 expression and docetaxel-induced apoptosis and to determine whether prostate cancer responses to docetaxel treatment differ with DRG2 expression.
Materials and methods: Prostate cancer cell lines were LNCaP, PC3 andDU145. MTT assay was used to determine cell viability. Western blotting analysis was performed using anti-DRG2 antibodies. Cells were transfected with DRG2 siRNA using an siRNA transfection reagent for DRG2 knockdown. The cell cycle was analyzed using flow cytometry, and apoptosis was detected using the Annexin V cell death assay.
Results: DRG2 expression differed in each prostate cancer cell line. Docetaxel blocked prostate cancer cell growth in a dose-dependent manner. In all cell lines, docetaxel suppressed the G1 phase in a dose-dependent manner. In contrast, increased G2/M arrest was observed with dose escalation in PC3 and LNCaP, but not in DU145. Docetaxel reduced DRG2 expression in a dose-dependent manner. Upon DRG2 knockdown in prostate cancer cells, an increase in the sub-G1 phase was observed without a change in the G1 or G2/M phase. When 4 nM docetaxel was administered to DRG2 knockdown prostate cancer cell lines, an increase in the sub-G1 phase was observed without increasing the G2/M phase, which was similar to that in DU145 before DRG2 knockdown. In PC3 and DU145, which rarely die from 4 nM docetaxel treatment, DRG2 knockdown increased docetaxel-induced annexin V (+) apoptosis by 8.7 and 2.7 times, respectively.
Conclusions: In prostate cancer cells, DRG2 regulates G2/M arrest after docetaxel treatment. DRG2 expression differs in each prostate cancer cell line, and thus induces different responses to docetaxel treatment. In prostate cancer cells with DRG2 knockdown, apoptosis increases without G2/M arrest in response to docetaxel treatment. These results show that inhibition of DRG2 expression can be useful to enhance docetaxel-induced apoptosis despite low-dose administration in castration-resistant prostate cancer.
keywords : prostate cancer, docetaxel, apoptosis, DRG2