Xiong Jikui, Wang Yan, Gu Yanli, Xue Yadong, Dang Lin, Li Yuzhen
Department of Dermatology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China.
Department of Pathology, Heilongjiang Provincial Hospital, Harbin, Heilongjiang 150036, P.R. China.
Oncol Lett. 2018 Apr;15(4):4767-4774. doi: 10.3892/ol.2018.7920. Epub 2018 Feb 1.
Malignant melanoma is characterized by rapid deterioration, early metastasis and high mortality. Cdk5 regulatory subunit-associated protein 1 (CDK5RAP1), which catalyzes 2-methylthio (ms) modification of mitochondrial transfer RNAs, has been reported to induce cancer cell apoptosis, by a phospho-c-Jun N-terminal kinase (p-JNK) signaling pathway. The present study was the first to report on the association between CDK5RAP1 deficiency and nuclear factor-κB (NF-κB) signaling pathway during the apoptosis process in human malignant melanoma (A375) cells. CDK5RAP1 small interfering RNA (siRNA) and control siRNA were transfected into A375 cells. CDK5RAP1 deficiency inhibited Ca influx in A375 cells. CDK5RAP1 deficiency also suppressed the proliferation of A375 cells, induced A375 cells apoptosis, and increased the generation of reactive oxygen species (ROS). In addition, CDK5RAP1 deficiency induced the phosphorylation of NF-κB and Bcl-2/Bcl-xl-associated death promoter (Bad). Notably, the phosphorylation of B-cell lymphoma-xl (Bcl-xl) and B-cell lymphoma-2 (Bcl-2) was downregulated by CDK5RAP1 deficiency. Pretreatment with pyrrolidine dithiocarbamate (PDTC), the inhibitor of NF-κB, prevented the decrease in cell proliferation and apoptosis induced by CDK5RAP1 deficiency in A375 cells. However, pretreatment with PDTC did not affect the generation of ROS in A375 cells, indicating that ROS is an upstream target of NF-κB signaling pathway during the apoptosis process. Taken together, CDK5RAP1 deficiency induces cell apoptosis in malignant melanoma A375 cells via the NF-κB signaling pathway. The results from the present study indicated a potential novel candidate for the treatment of skin cancer.
恶性黑色素瘤的特点是病情迅速恶化、早期转移和高死亡率。据报道，细胞周期蛋白依赖性激酶5调节亚基相关蛋白1（CDK5RAP1）催化线粒体转移RNA的2-甲硫基（ms）修饰，通过磷酸化c-Jun氨基末端激酶（p-JNK）信号通路诱导癌细胞凋亡。本研究首次报道了人类恶性黑色素瘤（A375）细胞凋亡过程中CDK5RAP1缺陷与核因子-κB（NF-κB）信号通路之间的关联。将CDK5RAP1小干扰RNA（siRNA）和对照siRNA转染到A375细胞中。CDK5RAP1缺陷抑制了A375细胞中的钙离子内流。CDK5RAP1缺陷还抑制了A375细胞的增殖，诱导A375细胞凋亡，并增加了活性氧（ROS）的产生。此外，CDK5RAP1缺陷诱导了NF-κB和Bcl-2/Bcl-xl相关死亡促进因子（Bad）的磷酸化。值得注意的是，CDK5RAP1缺陷下调了B细胞淋巴瘤-xl（Bcl-xl）和B细胞淋巴瘤-2（Bcl-2）的磷酸化。用NF-κB抑制剂吡咯烷二硫代氨基甲酸盐（PDTC）预处理可防止CDK5RAP1缺陷诱导的A375细胞增殖减少和凋亡。然而，PDTC预处理并不影响A375细胞中ROS的产生，表明ROS是凋亡过程中NF-κB信号通路的上游靶点。综上所述，CDK5RAP1缺陷通过NF-κB信号通路诱导恶性黑色素瘤A375细胞凋亡。本研究结果表明了一种治疗皮肤癌的潜在新候选药物。
