Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 126 Xinmin Street, Changchun, 130021, Jilin Province, China.
Mol Biol Rep. 2023 Aug;50(8):6627-6641. doi: 10.1007/s11033-023-08495-1. Epub 2023 Jun 26.
Glutamine metabolism is critical for development of hepatocellular carcinoma (HCC), which makes it a novel promising treatment target. However, clinical evidence suggested glutamine withdrawal therapy does not achieved the desired tumor suppression. Therefore, it is valuable to investigate the survival mechanisms of tumors with glutamine deprivation.
The HCC cells were cultured in glutamine-free medium or supplemented with glutamine metabolites or ferroptosis inhibitors. The parameters related to ferroptosis and the activity of GSH synthesis-related enzymes of the HCC cells were detected by corresponding kits. The expressions of glutamate oxaloacetate transaminase 1 (GOT1), c-Myc and Nrf2 were detected by western blot and qRT-PCR. The chromatin immunoprecipitation and luciferase reporter assays were performed to investigate the correlation between c-Myc and GOT1. The siRNAs of c-Myc and GOT1 were used to explore their roles in GSH (GSH) synthesis and ferroptosis in vitro and in vivo.
Glutamine deprivation-induced ferroptosis did not completely inhibit HCC cells proliferation. Glutamine deprivation activated the expression of c-Myc, which promoted the transcription of GOT1 and Nrf2, consequently maintaining the GSH synthesis and inhibiting ferroptosis. In addition, combined inhibition of GOT1 with glutamine deprivation could result in better inhibition of HCC in vitro and in vivo.
In our work, the results indicate that GOT1 induced by c-Myc may play an important role in combating ferroptosis due to glutamine deprivation, making it a significant target in glutamine withdrawal therapy. This study provides a theoretical foundation for the clinical targeted therapy for HCC.
谷氨酰胺代谢对于肝细胞癌（HCC）的发展至关重要，这使其成为一种有前途的治疗新靶点。然而，临床证据表明，谷氨酰胺耗竭疗法并未达到预期的肿瘤抑制效果。因此，研究谷氨酰胺剥夺条件下肿瘤的生存机制具有重要价值。
将 HCC 细胞在无谷氨酰胺培养基或补充谷氨酰胺代谢物或铁死亡抑制剂的条件下培养。通过相应试剂盒检测 HCC 细胞与铁死亡相关的参数以及谷胱甘肽（GSH）合成相关酶的活性。通过 Western blot 和 qRT-PCR 检测谷氨酸草酰乙酸转氨酶 1（GOT1）、c-Myc 和 Nrf2 的表达。通过染色质免疫沉淀和荧光素酶报告基因检测，研究 c-Myc 与 GOT1 之间的相关性。使用 siRNAs 沉默 c-Myc 和 GOT1，以探讨它们在体外和体内 GSH（GSH）合成和铁死亡中的作用。
谷氨酰胺剥夺诱导的铁死亡并不能完全抑制 HCC 细胞的增殖。谷氨酰胺剥夺激活了 c-Myc 的表达，从而促进了 GOT1 和 Nrf2 的转录，进而维持了 GSH 合成并抑制了铁死亡。此外，联合 GOT1 抑制与谷氨酰胺剥夺可导致 HCC 在体外和体内更好的抑制效果。
在我们的工作中，结果表明，c-Myc 诱导的 GOT1 可能在对抗由于谷氨酰胺剥夺引起的铁死亡中发挥重要作用，使其成为谷氨酰胺耗竭疗法的重要靶点。该研究为 HCC 的临床靶向治疗提供了理论基础。
