Huang Ke, Zhao Wei, Wang Xuqiao, Qiu Yingfei, Liu Zelin, Chen Rui, Liu Wei, Liu Bin
School/Hospital of Stomatology, Lanzhou University, Lanzhou, China.
Peking University People's Hospital, Peking University, Beijing, China.
Front Oncol. 2021 Apr 1;11:649176. doi: 10.3389/fonc.2021.649176. eCollection 2021.
Glioma has one of the highest mortality rates of all tumors of the nervous system and commonly used treatments almost always fail to achieve tumor control. Low-dose carbon-ion radiation can effectively target cancer and tumor cells, but the mechanisms of growth inhibition induced by heavy-ion radiation the PI3K/Akt signaling pathway are unknown, and inhibition by heavy-ion radiation is minor in C6 cells.
Carbon-ion radiation was used to investigate the effects of heavy-ion radiation on C6 cells, and suppression of Akt was performed using perifosine. MTT assays were used to investigate optimal perifosine treatment concentrations. Clone formation assays were used to investigate the growth inhibition effects of carbon-ion radiation and the effects of radiation with Akt inhibition. Lactate dehydrogenase release, superoxide dismutase activity, and malondialdehyde content were assessed to investigate oxidative stress levels. Expression levels of proteins in the PI3K/Akt/p53 signaling pathway were assessed western blotting.
The 10% maximum inhibitory concentration of perifosine was 19.95 μM. In clone formation assays there was no significant inhibition of cell growth after treatment with heavy-ion irradiation, whereas perifosine enhanced inhibition. Heavy-ion radiation induced lactate dehydrogenase release, increased the level of malondialdehyde, and reduced superoxide dismutase activity. Akt inhibition promoted these processes. Heavy-ion radiation treatment downregulated Akt expression, and upregulated B-cell lymphoma-2 (Bcl-2) expression. p53 and Bcl-2 expression were significantly upregulated, and Bcl-2-associated X protein (Bax) expression was downregulated. The expression profiles of pAkt, Bcl-2, and Bax were reversed by perifosine treatment. Caspase 3 expression was upregulated in all radiation groups.
The growth inhibition effects of low-dose heavy-ion irradiation were not substantial in C6 cells, and Akt inhibition induced by perifosine enhanced the growth inhibition effects proliferation inhibition, apoptosis, and oxidative stress. Akt inhibition enhanced the effects of heavy-ion radiation, and the PI3K/Akt/p53 signaling pathway may be a critical component involved in the process.
神经胶质瘤在所有神经系统肿瘤中死亡率最高，常用治疗方法几乎总是无法实现肿瘤控制。低剂量碳离子辐射可有效靶向癌细胞和肿瘤细胞，但重离子辐射诱导生长抑制的机制以及PI3K/Akt信号通路尚不清楚，且重离子辐射对C6细胞的抑制作用较小。
采用碳离子辐射研究重离子辐射对C6细胞的影响，并使用哌立福辛抑制Akt。采用MTT法研究哌立福辛的最佳处理浓度。采用克隆形成试验研究碳离子辐射的生长抑制作用以及Akt抑制对辐射效果的影响。评估乳酸脱氢酶释放、超氧化物歧化酶活性和丙二醛含量以研究氧化应激水平。通过蛋白质印迹法评估PI3K/Akt/p53信号通路中蛋白质的表达水平。
哌立福辛的10%最大抑制浓度为19.95μM。在克隆形成试验中，重离子照射处理后细胞生长无明显抑制，而哌立福辛增强了抑制作用。重离子辐射诱导乳酸脱氢酶释放，增加丙二醛水平，并降低超氧化物歧化酶活性。抑制Akt可促进这些过程。重离子辐射处理下调Akt表达，并上调B细胞淋巴瘤-2（Bcl-2）表达。p53和Bcl-2表达显著上调，而Bcl-2相关X蛋白（Bax）表达下调。哌立福辛处理可逆转pAkt、Bcl-2和Bax的表达谱。所有辐射组中半胱天冬酶3表达均上调。
低剂量重离子辐射对C6细胞的生长抑制作用不显著，哌立福辛诱导的Akt抑制通过增殖抑制、凋亡和氧化应激增强了生长抑制作用。抑制Akt增强了重离子辐射的作用，PI3K/Akt/p53信号通路可能是该过程中的关键组成部分。
