Identification of Akt1 as a potent therapeutic target for oral squamous cell carcinoma
Identification of Akt1 as a potent therapeutic target for oral squamous cell carcinoma
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DOI：
10.3892/ijo.2015.3134
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发表时间：
2015-10-01
影响因子：
5.2
通讯作者：
Hamakawa, Hiroyuki
中科院分区：
文献类型：
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作者：
Nakashiro, Koh-Ichi;Tanaka, Hiroshi;Hamakawa, Hiroyuki
癌基因成瘾可以为人类恶性肿瘤提供治疗机会。在这项研究中，我们的目的是确定关键癌基因的口腔鳞状细胞癌（OSCC）的发展和进展。我们使用应用生物系统人类基因组调查阵列确定了10个原发性OSCC和10个人类OSCC细胞系的基因表达谱。Akt1是唯一一个在所有口腔鳞癌组织和培养细胞中表达的基因，而在非肿瘤组织和细胞中不表达。Western blot分析显示Aka蛋白在口腔鳞癌组织和细胞系中均过表达。免疫组化结果显示，63例原发性OSCC中有59例（94%）表达Akt1蛋白。为了阐明Akt 1在人类OSCC细胞中的致癌功能，我们使用RNA干扰。我们设计并合成了5个针对Akt1的小分子干扰RNA（siAkt1）。体外转染siAkt1的人口腔鳞癌细胞明显抑制其Akt1蛋白的表达，并显着降低其生长速度。此外，去端胶原介导的全身siAkt1给药显著抑制了在无胸腺裸鼠中皮下异种移植的人OSCC肿瘤的生长。我们还发现合成的siAkt1对原代培养的OSCC细胞的生长具有抑制作用。最后，我们研究了Akt1抑制的生长抑制作用的分子机制，使用基因芯片分析转染siAkt1的人口腔鳞癌细胞。Aka的敲低诱导了肿瘤抑制基因CDKN2B的表达，并降低了支持恶性表型的TGFBR 1的表达。这些结果表明，阿卡功能作为一个关键的癌基因在人类口腔鳞状细胞癌细胞，因此可能是一个合适的目标，为新的口腔鳞状细胞癌治疗。
Oncogene addiction can provide therapeutic opportunities in human malignancies. In this study, we aimed to identify critical oncogenes for oral squamous cell carcinoma (OSCC) development and progression. We determined gene expression profiles in 10 primary OSCCs and 10 human OSCC cell lines using Applied Biosystems Human Genome Survey Arrays. Akt1 was the only gene identified that was expressed in all OSCC tissues and cultured cells, but not in non-neoplastic tissues and cells. Subsequently, western blot analysis showed that Aka protein was overexpressed in OSCC tissues and cell lines. Immunohistochemistry also showed Akt1 protein expression in 59 of 63 (94%) primary OSCCs. To clarify the oncogenic function of Akt1 in human OSCC cells, we used RNA interference. We designed and synthesized 5 small interfering RNAs specific for Akt1 (siAkt1). Transfecting human OSCC cells with siAkt1 in vitro markedly suppressed their expression of Akt1 protein and significantly reduced their growth rate. Furthermore, the growth of human OSCC tumors which had been subcutaneously xenografted in athymic nude mice lacking interferon responses was markedly inhibited by atelocollagen-mediated systemic siAkt1 administration. We also found that synthetic siAkt1 had an inhibitory effect on the growth of primary cultured OSCC cells. Finally, we investigated the molecular mechanisms involved in the growth inhibitory effect of Akt1 suppression using microarray analysis of human OSCC cells transfected with siAkt1. Knockdown of Aka induced the expression of CDKN2B, a tumor suppressor gene, and reduced the expression of TGFBR1, which supports malignant phenotypes. These results suggest that Aka functions as a critical oncogene in human OSCC cells and may therefore be an appropriate target for novel OSCC therapies.