Prasad Rajendra, Panchal Sonia, Rani Isha, Kishan Jai, Parashar Gaurav
Department of Biochemistry, M.M. Institute of Medical Sciences and Research (MMIMSR), Maharishi Markandeshwar University (MMU), Mullana, Ambala, India.
Department of Respiratory Medicine, M.M. Institute of Medical Sciences and Research (MMIMSR), Maharishi Markandeshwar University (MMU), Mullana, Ambala, India.
Indian J Clin Biochem. 2023 Jan;38(1):120-127. doi: 10.1007/s12291-022-01047-7. Epub 2022 May 19.
Lung cancer is a severe and the leading cause of cancer related deaths worldwide. The recurrent h-TERT promoter mutations have been implicated in various cancer types. Thus, the present study is extended to analyze h-TERT promoter mutations from the North Indian lung carcinoma patients. Total 20 histopathologically and clinically confirmed cases of lung cancer were enrolled in this study. The genomic DNA was extracted from venous blood and subjected to amplification using appropriate h-TERT promoter primers. Amplified PCR products were subjected for DNA Sanger sequencing for the identification of novel h-TERT mutations. Further, these identified h-TERT promoter mutations were analysed for the prediction of pathophysiological consequences using bioinformatics tools such as Tfsitescan and CIIDER. The average age of patients was 45 ± 8 years which was categorized in early onset of lung cancer with predominance of male patients by 5.6 fold. Interestingly, h-TERT promoter mutations were observed highly frequent in lung cancer. Identified mutations include c. G272A, c. T122A, c. C150A, c. 123 del C, c. C123T, c. G105A, c. 107 Ins A, c. 276 del C corresponding to -168 G>A, -18 T>A, -46 C>A, -19 del C, -19 C>T, -1 G>A, -3 Ins A, -172 del C respectively from the translation start site in the promoter of the telomerase reverse transcriptase gene which are the first time reported in germline genome from lung cancer. Strikingly, c. -18 T>A [C.T122A] was found the most prevalent variant with 75% frequency. Notwithstanding, other mutations viz c. -G168A [c. G272A] and c. -1 G>A [c. G105A] were found to be at 35% and 15% frequency respectively whilst the rest of the mutations were present at 10% and 5% frequency. Additionally, bioinformatics analysis revealed that these mutations can lead to either loss or gain of various transcription factor binding sites in the h-TERT promoter region. Henceforth, these mutations may play a pivotal role in h-TERT gene expression. Taken together, these identified novel promoter mutations may alter the epigenetics and subsequently various transcription factor binding sites which are of great functional significance. Thereby, it is plausible that these germline mutations may involve either as predisposing factor or direct participation in the pathophysiology of lung cancer through entangled molecular mechanisms.
肺癌是一种严重的疾病，也是全球癌症相关死亡的主要原因。h-TERT启动子的复发性突变与多种癌症类型有关。因此，本研究扩展至分析北印度肺癌患者的h-TERT启动子突变。本研究共纳入20例经组织病理学和临床确诊的肺癌病例。从静脉血中提取基因组DNA，并使用合适的h-TERT启动子引物进行扩增。对扩增的PCR产物进行DNA Sanger测序，以鉴定新的h-TERT突变。此外，使用Tfsitescan和CIIDER等生物信息学工具对这些鉴定出的h-TERT启动子突变进行分析，以预测其病理生理后果。患者的平均年龄为45±8岁，属于肺癌早发，男性患者占比高5.6倍。有趣的是，h-TERT启动子突变在肺癌中观察到频率很高。鉴定出的突变包括c.G272A、c.T122A、c.C150A、c.123delC、c.C123T、c.G105A、c.107InsA、c.276delC，分别对应端粒酶逆转录酶基因启动子中翻译起始位点的-168G>A、-18T>A、-46C>A、-19delC、-19C>T、-1G>A、-3InsA、-172delC，这些是首次在肺癌种系基因组中报道。引人注目的是，c.-18T>A[C.T122A]被发现是最常见变异，频率为75%。尽管如此，其他突变即c.-G168A[c.G272A]和c.-1G>A[c.G105A]的频率分别为35%和15%，而其余突变的频率为10%和5%。此外，生物信息学分析表明，这些突变可导致h-TERT启动子区域各种转录因子结合位点的丧失或增加。因此，这些突变可能在h-TERT基因表达中起关键作用。综上所述，这些鉴定出的新启动子突变可能会改变表观遗传学，进而改变各种转录因子结合位点，具有重要的功能意义。因此，这些种系突变可能作为易感因素或通过复杂的分子机制直接参与肺癌的病理生理过程，这是有道理的。
