【摘要】 背景与目的:全反式维甲酸(all-transretinoicacid,ATRA)和1α,25二羟维生素D3[1alpha,25-dihydroxyvitaminD3,1,25(OH)2D3]已被证实能诱导肿瘤细胞分化,并用于造血系统肿瘤的治疗,但其对实体瘤的影响研究较少。本研究旨在通过单独和联合使用ATRA和1,25(OH)2D3,观察其对肝癌HepG2细胞生长和细胞周期的影响,并探讨其相关机制。方法:HepG2细胞经过不同浓度的ATRA和1,25(OH)2D3单独或联合用药处理后,用MTT法检测细胞抑制率、显微镜观察细胞形态的改变、流式细胞仪检测细胞周期和细胞凋亡的变化,同时分别用逆转录多聚酶链反应(reversetranscription-polymerasechainreaction,RT-PCR)及流式细胞仪(flowcytometry,FCM)检测细胞周期负调节基因p21WAF1/CIP1和p27KIP1的mRNA及蛋白的表达情况。结果:单独使用ATRA或1,25(OH)2D3和联合用药的HepG2细胞生长均受到抑制,并呈浓度和时间依赖关系,其中联合用药组抑制率明显高于单独用药组(P<0.05)。经10nmol/L1,25(OH)2D3及联合用药诱导72h的HepG2细胞G1期细胞占(54.27±3.69)%和(65.64±5.65)%,与对照组[(40.40±1.91)%]相比明显增高(P<0.05),而1μmol/LATRA组的细胞周期与对照组相比无明显差异(P>0.05);同时各实验组均有细胞凋亡产生(P<0.05),并以联合用药组最为显著。RT-PCR显示10nmol/L1,25(OH)2D3和联合用药处理HepG2细胞24h,p21WAF1/CIP1mRNA表达与对照组相比分别增高35%和56%;FCM显示两组细胞的P21WAF1/CIP1和P27KIP1的蛋白表达与对照组相比明显增高(P<0.05),联合用药组更为显著,但经1μmol/LATRA诱导的细胞P21WAF1/CIP1和P27KIP1的蛋白表达未见明显改变。结论:ATRA和1,25(OH)2D3均能够抑制HepG2细胞生长,诱导细胞凋亡,1,25(OH)2D3对细胞周期的影响作用是使细胞阻滞在G1期,其作用机制可能与其上调P21WAF1/CIP1和P27KIP1蛋白的表达有关,当与ATRA联合用药时,能够对HepG2细胞生长产生协同抑制作用。更多还原

【Abstract】 BACKGROUND & OBJECTIVE: All-trans retinoic acid (ATRA) and 1,25-dihydroxy vitamin D3 [1,25(OH)2D3] can inhibit the proliferation of tumor cells and induce their differentiation. They have been used to treat leukemia, but their effects on solid tumors remain unclear. This study was to investigate the effects of ATRA and 1,25(OH)2D3 on growth and cell cycle of human hepatoma cell line HepG2, and explore the molecular mechanism. METHODS: After HepG2 cells were treated with ATRA, 1,25(OH)2D3, or the combination of both chemicals, cell survival was assessed by MTT assay, morphologic changes were observed under light microscope, cell cycle and apoptosis were determined by flow cytometry (FCM) with dual staining of AnnexinV/PI, and the expression of p21WAF/CIP1 and p27KIP1 mRNA and protein were determined by reverse transcription-polymerase chain reaction (RT-PCR) and FCM. RESULTS: ATRA and 1,25(OH)2D3, used alone or in combination, inhibited the growth of HepG2 cells in a time- and dose-dependent manner. The inhibition was more obvious in the combination group than in ATRA group and 1,25(OH)2D3 group (P<0.05). FCM analysis indicated that 10 nmol/L 1,25(OH)2D3, used alone or in combination with ATRA for 72 h, strongly induced G1 phase arrest of HepG2 cells [(54.27±3.69)% and (65.64±5.65)% vs. (40.40±1.91)% of the control, P<0.05], but 1 μmol/L ATRA did not show obvious effect. All of them induced apoptosis (P<0.05). The mRNA level of p21WAF/CIP1 was enhanced by 35% and 56% of control in the cells treated with 10 nmol/L 1,25(OH)2D3 or 1,25(OH)2D3 combined with ATRA for 24 h. The combination of 1,25(OH)2D3 and ATRA markedly enhanced the protein levels of p21WAF/CIP1 and p27KIP1 as compared with 1,25(OH)2D3 alone, and 1 μmol/L ATRA did not enhance the protein levels of p21WAF/CIP1 and p27KIP1 in HepG2 cells. CONCLUSIONS: ATRA and 1,25(OH)2D3 could inhibit growth and induce apoptosis of HepG2 cells, and the molecular basis of the cell cycle blockade by 1,25(OH)2D3 may be associated with the up-regulation of CDK inhibitors p21WAF/CIP1 and p27KIP1, which mediate G1 arrest. Furthermore, the combination of ATRA and 1,25(OH)2D3 can exert synergistic inhibitory effect on the growth of HepG2 cells.更多还原