目的：探讨全反式维甲酸（ ATRA）对人乳腺癌细胞MCF-7增殖的影响及可能机制。方法： MCF-7细胞培养于含10％胎牛血清、1％青霉素／链霉素的DMEM培养液，蛋白免疫印迹检测蛋白质的表达，MTT法和溴脱氧尿嘧啶核苷（ BrdU）掺入法测定细胞增殖，TUNEL法测定细胞凋亡，携带目标基因shRNA的慢病毒用于沉默目标基因，过氧化物酶体增殖物激活受体γ（ PPARγ）的活性采用商品化的试剂盒测定。结果： ATRA处理可抑制MCF-7细胞的增殖，促进其凋亡；同时，ATRA以时间依赖方式刺激停靠蛋白1（ DOK1）的表达。沉默DOK1可降低ATRA对MCF-7细胞增殖和凋亡的影响。此外，DOK1基因沉默可抑制PPARγ的表达和活性。而PPARγ选择性抑制剂GW9662可减轻ATRA对MCF-7细胞增殖的抑制和对细胞凋亡的促进作用。结论： ATRA通过抑制细胞增殖、促进细胞凋亡而抑制MCF-7细胞的生存，这一作用经DOK1激活的PPARγ介导。%AIM:To investigate the potential effect of all-trans retinoic acid (ATRA) on the proliferation of human breast cancer MCF-7 cells and its underlying mechanism.METHODS:Human breast cancer MCF-7 cells were in-cubated in DMEM supplemented with 10%fetal bovine serum and 1%penicillin/streptomycin.Western blot was performed to detect the protein expression and its phosphorylation.MTT assay and bromodeoxyuridine ( BrdU) incorporation, and TUNEL staining were carried out to determine the cell proliferation and apoptosis, respectively.Lentivirus carrying shRNA sequences targeting the gene of docking protein 1 ( DOK1 ) was used to silence DOK1 expression.The activity of peroxi-some proliferator-activated receptor gamma ( PPARγ) was measured using a PPARγtranscription factor assay kit.RE-SULTS:ATRA treatment suppressed the proliferation and promoted the apoptosis of MCF-7 cells.ATRA was also found to induce DOK1 expression in a time-dependent manner.Silence of DOK1 mitigated anti-cancer effect of ATRA evidenced by recovered the cell proliferation and reduced the cell apoptosis.In addition, DOK1 knockdown inhibited PPARγexpression and activity.Furthermore, inhibition of PPARγwith its specific inhibitor GW9662 attenuated impacts of ATRA on the cell proliferation and apoptosis.CONCLUSION: ATRA suppresses MCF-7 cell survival through inhibiting cell proliferation and promoting cell apoptosis, which is mediated by DOK1-activated PPARγ.
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