Zhang Xin, Ding Changrui, Tian Hongfang, Dong Xinjun, Meng Xianfu, Zhu Wenwei, Liu Bing, Wang Lan, Huang Min, Li Chengxin
Department of Dermatology, Chinese People's Liberation Army General Hospital, Beijing, China.
Department of Dermatology, The First Affiliated Hospital of Qiqihar Medical College, Qiqihar, China.
Cell Physiol Biochem. 2017;43(1):147-157. doi: 10.1159/000480333. Epub 2017 Aug 28.
BACKGROUND/AIMS: Cutaneous melanoma is one of the leading causes of cancer deaths with an increasing incidence worldwide. A KRAB-containing zinc finger protein member, zinc finger 23 (ZNF23), was reduced in some types of tumors and inhibited cell growth by inducing cell cycle arrest. However, the role of ZNF23 expression is still poorly understood in melanoma.
The level of ZNF23 expression was detected in cutaneous melanoma, adjacent normal skin tissues and cutaneous melanoma cell lines using immunohistochemistry and western blotting. The correlations between ZNF23 expression and other clinicopathologic parameters were analyzed in melanoma patients. Ectopic expression of ZNF23 plasmid was transfected into melanoma cells, SK-MEL-1 and SK-MEL-28. MTT, flow cytometry and transwell assay were used to measure cell proliferation, apoptosis, invasion and migration abilities, respectively. Mitochondrial functions and structures were detected by mitochondrial membrane potential assay and Transmission electron microscopy (TEM) method in melanoma cells transfected with overexpressing ZNF23 plasmid or empty vector. Western blotting was performed to detect the levels of ZNF23, p53, p27, Bcl-2 and cleaved caspase-3 after overexpressing of ZNF23 in melanoma cells.
ZNF23 was elevated in adjacent normal skin tissues compared with melanoma tissues. Patients with low level of ZNF23 expression exhibited higher incidence of lymphoid metastasis, thicker size of tumors and worse outcome. By using Cox's regression analysis, ZNF23 expression, tumor thickness and lymph node metastasis were the independent prognostic factors for overall survival (p < 0.05). Results from cellular experiments indicated that ectopic expression of ZNF23 induced cell apoptosis by activation of caspase-3, p27, p53 expression and down-regulation of Bcl-2 through mitochondria-dependent pathway.
Decreased ZNF23 was contributed to melanoma progression and poor survival with mitochondria-dependent pathway. It indicated that ZNF23 could be a promising therapeutic biomarker candidate for cutaneous melanoma.
背景/目的：皮肤黑色素瘤是全球癌症死亡的主要原因之一，其发病率呈上升趋势。一种含KRAB的锌指蛋白成员，锌指23（ZNF23），在某些类型的肿瘤中表达降低，并通过诱导细胞周期停滞来抑制细胞生长。然而，ZNF23表达在黑色素瘤中的作用仍知之甚少。
采用免疫组织化学和蛋白质印迹法检测皮肤黑色素瘤、癌旁正常皮肤组织及皮肤黑色素瘤细胞系中ZNF23的表达水平。分析黑色素瘤患者中ZNF23表达与其他临床病理参数之间的相关性。将ZNF23质粒异位表达转染至黑色素瘤细胞SK-MEL-1和SK-MEL-28中。分别采用MTT法、流式细胞术和Transwell实验检测细胞增殖、凋亡、侵袭和迁移能力。通过线粒体膜电位检测和透射电子显微镜（TEM）法检测过表达ZNF23质粒或空载体转染的黑色素瘤细胞中的线粒体功能和结构。在黑色素瘤细胞中过表达ZNF23后，采用蛋白质印迹法检测ZNF23、p53、p27、Bcl-2和裂解的caspase-3的水平。
与黑色素瘤组织相比，癌旁正常皮肤组织中ZNF23表达升高。ZNF23表达水平低的患者淋巴转移发生率更高，肿瘤体积更大，预后更差。通过Cox回归分析，ZNF23表达、肿瘤厚度和淋巴结转移是总生存的独立预后因素（p<0.05）。细胞实验结果表明，ZNF23的异位表达通过激活caspase-3、p27、p53表达并通过线粒体依赖途径下调Bcl-2来诱导细胞凋亡。
ZNF23表达降低通过线粒体依赖途径促进黑色素瘤进展并导致预后不良。这表明ZNF23可能是皮肤黑色素瘤一个有前景的治疗生物标志物候选物。
