RIPK4(受体相互作用蛋白激酶4),RIPK家族的一员,作为表皮分化的重要调节剂,皮肤炎症,和皮肤伤口修复。然而,直到现在,RIPK4在肿瘤发生中的作用仍然难以捉摸。目前尚无研究探讨RIPK4对皮肤鳞状细胞癌(SCC)信号通路的影响。目前尚不清楚RIPK4是否表达,可以影响表皮分化程度,也可以影响皮肤SCC的放射敏感性。迫切需要充分阐明RIPK4促进皮肤SCC癌变的生物学机制,并确定RIPK4表达水平是否可以预测皮肤SCC对放疗的敏感性。
人类皮肤SCC细胞系,用靶向RIPK4的小干扰RNA(siRNA)(siR-RIPK4)或阴性对照siRNA(siR-NC)转染A431。免疫印迹法检测RIPK4和Raf/MEK/ERK通路相关蛋白的表达。使用X射线辐射器在6MV下以不同的辐射剂量(0、2、6和10Gy)照射细胞。细胞增殖分析,集落形成试验,transwell细胞迁移和侵袭试验,进行细胞周期和细胞凋亡分析以研究RIPK4沉默对皮肤SCC恶性程度和放射敏感性的影响。
与siR-NC转染的A431细胞相比,用siR-RIPK4转染的A431细胞中RIPK4蛋白的表达显着降低。RIPK4沉默促进了扩散,菌落形成,迁移,和A431细胞系的侵袭能力,而细胞周期进程或细胞凋亡没有显着影响。与以前的文献相比,Raf/MEK/ERK途径不受皮肤SCC中RIPK4敲低的影响。RIPK4敲低不能逆转A431细胞对体外辐射的抗辐射性。
一般来说,尽管RIPK4的耗竭不能逆转A431细胞的体外抗辐射能力,它与皮肤SCC中更高的恶性潜能相似。据我们所知,这是首次报道RIPK4表达对皮肤SCC中Raf/MEK/ERK信号通路和放射敏感性的影响。对RIPK4在皮肤SCC中的分子机制的更好理解可能为皮肤SCC的预后和治疗提供有希望的生物标志物。
The
RIPK4 (receptor-interacting protein kinase 4), a member of the RIPK family, acts as an important regulator of epidermal differentiation, cutaneous inflammation, and cutaneous wound repair. However, Until now, the role of
RIPK4 in tumorigenesis remains elusive. There have been no studies exploring the effects of RIPK4 on the signaling pathway in cutaneous squamous cell carcinoma (SCC). It remains unknown whether
RIPK4 expression, which can affect the degree of epidermal differentiation can also influence the radiosensitivity of skin SCC. It is urgent to fully elucidate the biological mechanism by which RIPK4 promotes carcinogenesis in skin SCC and determine whether RIPK4 expression levels predicts the sensitivity to radiotherapy in skin SCC.
Human skin SCC cell line, A431, was transfected with either small interfering RNAs (siRNAs) targeting RIPK4 (siR-
RIPK4) or negative control siRNA (siR-NC). Western blotting was used to detect the expression of RIPK4 and Raf/MEK/ERK pathway-related proteins. The cells were irradiated using an X-ray irradiator at 6 MV with different radiation doses (0, 2, 6, and 10 Gy). Cell proliferation analysis, colony formation assay, transwell cell migration and invasion assay, cell cycle and apoptosis analysis were conducted to investigate the effect of RIPK4 silencing on skin SCC malignancy and radiosensitivity.
RIPK4 protein expression was significantly decreased in the A431 cells transfected with siR-
RIPK4, compared with the A431 cells transfected with siR-NC. RIPK4 silencing facilitated the proliferation, colony formation, migration, and invasion ability of A431 cell line, while cell cycle progression or cell apoptosis were not significantly influenced. In contrast with the previous literature, Raf/MEK/ERK pathway was not effected by RIPK4 knockdown in skin SCC. RIPK4 knockdown could not reverse the radiation resistance of A431 cells to irradiation in vitro.
In general, although depletion of RIPK4 cannot reverse the radiation resistance of A431 cells in vitro, it parallels higher malignancy potential in cutaneous SCC. To our knowledge, this is the first report of the effects of RIPK4 expression on the Raf/MEK/ERK signaling pathway and radiosensitivity in cutaneous SCC. The better understanding of the molecular mechanism of RIPK4 in cutaneous SCC may provide a promising biomarker for skin SCC prognosis and treatment.