Vahidi Sogand, Norollahi Seyedeh Elham, Agah Shahram, Samadani Ali Akbar
Clinical Research Development Unit of Poursina Hospital, Guilan University of Medical Sciences, Rasht, Iran.
Colorectal Research Center, Iran University of Medical Sciences, Tehran, Iran.
J Gastrointest Cancer. 2020 Sep;51(3):788-799. doi: 10.1007/s12029-020-00427-7.
Epigenetic modification including of DNA methylation, histone acetylation, histone methylation, histon phosphorylation and non-coding RNA can impress the gene expression and genomic stability and cause different types of malignancies and also main human disorder. Conspicuously, the epigenetic alteration special DNA methylation controls telomere length, telomerase activity and also function of different genes particularly hTERT expression. Telomeres are important in increasing the lifespan, health, aging, and the development and progression of some diseases like cancer.
This review provides an assessment of the epigenetic alterations of telomeres, telomerase and repression of its catalytic subunit, hTERT and function of long non-coding RNAs such as telomeric-repeat containing RNA (TERRA) in carcinogenesis and tumorgenesis of gastric cancer.
hTERT expression is essential and indispensable in telomerase activation through immortality and malignancies and also plays an important role in maintaining telomere length. Telomeres and telomerase have been implicated in regulating epigenetic factors influencing certain gene expression. Correspondingly, these changes in the sub telomere and telomere regions are affected by the shortening of telomere length and increased telomerase activity and hTERT gene expression have been observed in many cancers, remarkably in gastric cancer.
Epigenetic alteration and regulation of hTERT gene expression are critical in controlling telomerase activity and its expression. Graphical Abstract.
包括DNA甲基化、组蛋白乙酰化、组蛋白甲基化、组蛋白磷酸化和非编码RNA在内的表观遗传修饰可影响基因表达和基因组稳定性，导致不同类型的恶性肿瘤以及主要的人类疾病。值得注意的是，表观遗传改变特别是DNA甲基化控制端粒长度、端粒酶活性以及不同基因的功能，尤其是hTERT的表达。端粒在延长寿命、健康、衰老以及某些疾病如癌症的发生和发展中起着重要作用。
本综述评估了端粒、端粒酶及其催化亚基hTERT的表观遗传改变，以及长链非编码RNA如端粒重复序列RNA（TERRA）在胃癌发生和肿瘤发生中的作用。
hTERT表达在通过永生化和恶性肿瘤激活端粒酶方面至关重要且不可或缺，在维持端粒长度方面也起着重要作用。端粒和端粒酶参与调节影响某些基因表达的表观遗传因子。相应地，在许多癌症中，尤其是胃癌中，观察到亚端粒和端粒区域的这些变化受端粒长度缩短、端粒酶活性增加和hTERT基因表达增加的影响。
hTERT基因表达的表观遗传改变和调控在控制端粒酶活性及其表达方面至关重要。图形摘要。
