Arunkumar Ganesan, Murugan Avaniyapuram Kannan, Prasanna Srinivasa Rao Harikrishnan, Subbiah Shanmugam, Rajaraman Ramamurthy, Munirajan Arasambattu Kannan
Department of Genetics, Dr ALM PG Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai 600 113, India.
Department of Molecular Oncology, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia.
Biomed Rep. 2017 Apr;6(4):455-462. doi: 10.3892/br.2017.876. Epub 2017 Mar 17.
Oral squamous cell carcinoma (SCC) is the most common malignant tumor in India with 5-year survival rates totaling <50%. Recently, dysregulation of non-coding RNA was reported as a potential hallmark of carcinogenesis. Colon Cancer Associated Transcript 1 (CCAT1), an lncRNA located in chromosome 8q24, close to the c-Myc gene, has been reported to be overexpressed in many human cancers. In the present study, the authors analyzed the expression of CCAT1, c-Myc and the miRNAs miR155-5p, let7b-5p, miR490-3p and miR218-5p sponged by CCAT1 in 60 oral tumor and 8 normal tissue samples by reverse transcription-quantitative polymerase chain reaction. CCAT1 was significantly overexpressed in 27% (16/60) of oral tumors. Interestingly, a high level of c-Myc expression was observed in all CCAT1 overexpressing cases (P=0.0473). Furthermore, CCAT1 overexpression significantly downregulated miR155-5p (P=0.03) and let7b-5p (P<0.0001). Oral cancer cases expressing high level of CCAT1 (P=0.01) presented poor therapeutic outcome. To the best of the authors' knowledge, this is the first study to report the overexpression of the CCAT1 in oral SCCs, and the results suggested that CCAT1 overexpression may sponge miR155-5p and let7b-5p, and may account for poor treatment response.
口腔鳞状细胞癌（SCC）是印度最常见的恶性肿瘤，其5年生存率总计<50%。最近，非编码RNA的失调被报道为致癌作用的一个潜在标志。结肠癌相关转录本1（CCAT1）是一种位于8号染色体q24区域、靠近c-Myc基因的长链非编码RNA，据报道在许多人类癌症中过表达。在本研究中，作者通过逆转录定量聚合酶链反应分析了60份口腔肿瘤组织和8份正常组织样本中CCAT1、c-Myc以及被CCAT1吸附的miR155-5p、let7b-5p、miR490-3p和miR218-5p的表达情况。CCAT1在27%（16/60）的口腔肿瘤中显著过表达。有趣的是，在所有CCAT1过表达的病例中均观察到高水平的c-Myc表达（P = 0.0473）。此外，CCAT1过表达显著下调了miR155-5p（P = 0.03）和let7b-5p（P < 0.0001）。CCAT1表达水平高的口腔癌病例（P = 0.01）治疗效果较差。据作者所知，这是第一项报道CCAT1在口腔SCC中过表达的研究，结果表明CCAT1过表达可能吸附miR155-5p和let7b-5p，并可能导致治疗反应不佳。
