Cancer Biology Laboratory & DBT-AIST International Laboratory for Advanced Biomedicine (DAILAB), Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
Department of Biotechnology, Mizoram University, Aizawl, Mizoram 796 004, India.
Biomolecules. 2019 Jun 27;9(7):253. doi: 10.3390/biom9070253.
Protein kinase B (Akt) plays a very significant role in various cancers including oral cancer. However, it has three isoforms (Akt1, Akt2, and Akt3) and they perform distinct functions and even play contrasting roles in different cancers. Therefore, it becomes essential to evaluate the isoform-specific role of Akt in oral cancer. In the present study, an attempt has been made to elucidate the isoform-specific role of Akt in oral cancer. The immunohistochemical analysis of oral cancer tissues showed an overexpression of Akt1 and 2 isoforms but not Akt3. Moreover, the dataset of "The Cancer Genome Atlas" for head and neck cancer has suggested the genetic alterations of Akt1 and 2 tend to be associated with the utmost poor clinical outcome in oral cancer. Further, treatment of oral cancer cells with tobacco and its components such as benzo(a)pyrene and nicotine caused increased mRNA levels of Akt1 and 2 isoforms and also enhanced the aggressiveness of oral cancer cells in terms of proliferation, and clonogenic and migration potential. Finally, silencing of Akt1 and 2 isoforms caused decreased cell survival and induced cell cycle arrest at the G2/M phase. Akt1/2 silencing also reduced tobacco-induced aggressiveness by decreasing the clonogenic and migration potential of oral cancer cells. Moreover, silencing of Akt1 and 2 isoforms was found to decrease the expression of proteins regulating cancer cell survival and proliferation such as cyclooxygenase-2, B-cell lymphoma 2 (Bcl-2), cyclin D1, and survivin. Thus, the important role of Akt1 and 2 isoforms have been elucidated in oral cancer with in-depth mechanistic analysis.
蛋白激酶 B(Akt)在各种癌症中发挥着非常重要的作用,包括口腔癌。然而,它有三种同工型(Akt1、Akt2 和 Akt3),它们具有不同的功能,甚至在不同的癌症中发挥相反的作用。因此,评估 Akt 在口腔癌中的同工型特异性作用变得至关重要。在本研究中,我们试图阐明 Akt 在口腔癌中的同工型特异性作用。口腔癌组织的免疫组织化学分析显示 Akt1 和 2 同工型过表达,但 Akt3 没有。此外,“癌症基因组图谱”对头颈部癌症的数据表明,Akt1 和 2 的遗传改变往往与口腔癌的最差临床结局相关。进一步,用烟草及其成分如苯并(a)芘和尼古丁处理口腔癌细胞导致 Akt1 和 2 同工型的 mRNA 水平增加,并增强了口腔癌细胞的侵袭性,表现为增殖、克隆形成和迁移能力增强。最后,沉默 Akt1 和 2 同工型导致细胞存活率降低,并诱导细胞周期在 G2/M 期停滞。Akt1/2 沉默还通过降低口腔癌细胞的克隆形成和迁移能力来减少烟草诱导的侵袭性。此外,沉默 Akt1 和 2 同工型会降低调节癌细胞存活和增殖的蛋白的表达,如环氧化酶-2、B 细胞淋巴瘤 2(Bcl-2)、细胞周期蛋白 D1 和存活素。因此,深入的机制分析阐明了 Akt1 和 2 同工型在口腔癌中的重要作用。