全反式维甲酸对结直肠癌LOVO、SW480细胞系增殖、凋亡及受体表达的影响

Impact of all-trans retinoic acid on proliferation,apoptosis and expression of retinoic acid receptor in colorectal cancer cell LOVO and SW480

目的探讨全反式维甲酸(all-trans retinoic acid,ATRA)对微卫星稳定(microsatellite stable,MSS)和微卫星不稳定(mic-rosatellite instability,MSI)结直肠癌细胞系的生长抑制作用,以及对LOVO、SW480和维甲酸受体α(retinoic acid receptor-α,RAR-α)表达的影响。方法体外培养MSI结直肠癌细胞系LOVO及MSS结直肠癌细胞系SW480,应用不同浓度的ATRA进行刺激,并设置空白对照组和RAR-α抑制剂对照组。用MTT法分析两种细胞系肿瘤细胞的增殖变化,用RT-PCR技术及平均光密度比值分析RAR-αmRNA表达,用Western blot技术及平均光密度比值分析细胞凋亡蛋白Caspase-3、Caspase-8表达。结果与对照组相比,ATRA对两种细胞系的增殖均有抑制作用,并能有效刺激两种细胞系RAR-αmRNA和凋亡蛋白Caspase-3、Caspase-8的表达(P<0.05)。ATRA刺激后,MSS细胞系RAR-αmRNA、凋亡蛋白Caspase-3、Caspase-8表达高于MSI细胞系(P<0.05)。结论 ATRA能抑制结直肠癌细胞系MSS和MSI肿瘤细胞的增殖,促进这两种特性细胞系的凋亡并增加RAR-α的表达,其对MSS细胞系作用高于MSI细胞系。实验结果间接提示RAR-α减少可能与锯齿状病变广基途径发病机制有关。

Purpose Basic molecular changes of colorectal cancer is genomic instability, including microsatellite instability （ MSI）, DNA microsatellite repeat length change and chromosomal instability characterized by the whole or part of the chromosomal variation. All-trans retinoic acid （ATRA） effects on a variety of tumor cells with inhibition of growth, promotion of apoptosis, and induction of differentiation. The aim of this study was to investigate the effects of ATRA on proliferation, apoptosis and expression of retinoic acid receptor in colorectal cancer MSI cells and microsatellite stable （MSS） cells. Methods LOVO and SW480 cells were cuhured in vitro and treated with different concentrations of ATRA. Control group and retinoic acid receptor-α （RAR-α） inhibitor group were set. Cell proliferation was measured by MTT assay. RT-PCR was used to detect the expression of RAR-α mRNA. Western blot was employed to detect the apoptosis proteins （Caspase-3 and Caspase-8） in LOVO and SW480 cells. Results ATRA not only significantly inhibited the proliferation of LOVO and SW480 cells but also effectively stimulated the expression of both RAR-α mRNA and apoptosis protein Caspase-3 and Caspase-8 （P 〈 0. 05 ）. After ATRA treatment, MSS cell expression of RAR-α mRNA and Caspase-3, Caspase-8 was higher than that of MSI cells. Conclusion ATRA can inhibit the proliferation of both MSS cell and MSI cell and promote apoptosis of these cells and increase the expression of RARs-α. ATRA has higher effects on MSS cells than on MSI cells. The study also suggests that the pathogenesis of sessile serrated lesions may be related with the decrease of retinoic acid receptor.