Chen Li-Hsuen, Liu Dai-Wei, Chang Junn-Liang, Chen Peir-Rong, Hsu Lee-Ping, Lin Hon-Yi, Chou Yu-Fu, Lee Chia-Fong, Yang Miao-Chun, Wen Yu-Hsuan, Hsu Wen-Lin, Weng Ching-Feng
Department of Life Science and the Institute of Biotechnology, National Dong Hwa University, Hualien, Taiwan.
Department of Radiation Oncology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.
J Exp Clin Cancer Res. 2015 Feb 24;34(1):20. doi: 10.1186/s13046-015-0138-5.
Aberrant insulin-like growth factor-binding protein 7 (IGFBP-7) expression has been found in various cancers such as prostate, breast, and colon. IGFBP-7 induced the apoptosis of tumor and potentially predicted the clinical outcome in some cancers is further demonstrated. This study investigates the causes and underlying mechanisms of aberrant IGFBP-7 expression in unravelling head and neck squamous cell carcinoma (HNSCC).
A total of 47 oral tongue cancer patient samples were primarily analyzed for the methylation status in 5' region of IGFBP-7 by methylation-specific PCR (MS-PCR). Subsequently the invasion, overexpression, and knockdown of IGFBP-7 in the HNSCC A253 invasive subpopulation were employed to examine the effect of IGFBP-7. The epithelial-mesenchymal transition (EMT) marker genes and AKT/GSK3β/β-catenin signaling were further evaluated by Western blot for the understanding the role of aberrant IGFBP-7 expression and thereof putative mechanism.
EMT expressed in the invasive subpopulation of HNSCC cell lines (A253 and RPMI 2650) was contemporary with the down-regulation of IGFBP-7. After treatment with 5-AZA-2' deoxycytidine, the de-methylated CpG sites in the 5' region of IGFBP-7 were observed and IGFBP-7 mRNA expression was also restored. Accordingly, re-expression IGFBP-7 in invasive subpopulation of A253 could induce the mesenchymal-epithelial transition (MET) and concurrently inhibited the cell invasion. Moreover, IGFBP-7 methylation status of 47 oral tongue tumors showed a positive correlation to invasive depth of the tumor, loco-regional recurrence, and cancer sequence.
IGFBP-7 can alter EMT relative marker genes and suppress cell invasion in A253 cell through AKT/GSK3β/β-catenin signaling. The epigenetic control of IGFBP-7 in the invasion and metastasis of HNSCC was reported, suggesting that IGFBP-7 could be a prognostic factor for the probability of invasion and a therapeutic remedy.
在前列腺癌、乳腺癌和结肠癌等多种癌症中发现胰岛素样生长因子结合蛋白7（IGFBP - 7）表达异常。进一步证实了IGFBP - 7可诱导肿瘤细胞凋亡，并可能预测某些癌症的临床结局。本研究旨在探究头颈部鳞状细胞癌（HNSCC）中IGFBP - 7表达异常的原因及潜在机制。
通过甲基化特异性PCR（MS - PCR）对47例口腔舌癌患者样本进行IGFBP - 7 5'区域甲基化状态的初步分析。随后，在HNSCC A253侵袭亚群中进行IGFBP - 7的侵袭、过表达和敲低实验，以检测IGFBP - 7的作用。通过蛋白质免疫印迹法进一步评估上皮 - 间质转化（EMT）标记基因和AKT/GSK3β/β - 连环蛋白信号通路，以了解IGFBP - 7表达异常的作用及其潜在机制。
在HNSCC细胞系（A253和RPMI 2650）的侵袭亚群中，EMT的表达与IGFBP - 7的下调同时出现。用5 - 氮杂 - 2'-脱氧胞苷处理后，观察到IGFBP - 7 5'区域的CpG位点去甲基化，且IGFBP - 7 mRNA表达也得以恢复。相应地，在A253侵袭亚群中重新表达IGFBP - 7可诱导间质 - 上皮转化（MET），并同时抑制细胞侵袭。此外，47例口腔舌肿瘤的IGFBP - 7甲基化状态与肿瘤侵袭深度、局部区域复发和癌症分期呈正相关。
IGFBP - 7可通过AKT/GSK3β/β - 连环蛋白信号通路改变A253细胞中EMT相关标记基因并抑制细胞侵袭。本研究报道了IGFBP - 7在HNSCC侵袭和转移中的表观遗传调控，提示IGFBP - 7可能是侵袭可能性的预后因素及治疗靶点。
