Department of Neurosurgery, Jinan University First Affiliated Hospital, Tianhe District, Guangzhou, China.
Department of Neurosurgery, Hainan General Hospital, Xiuying District, Haikou, Hainan Province, China, China.
Endokrynol Pol. 2020;71(5):425-431. doi: 10.5603/EP.a2020.0053. Epub 2020 Aug 14.
Pituitary adenomas constitute one of the most common intracranial tumours. The mouse double minute 2 homologue (MDM2) is considered as an important oncogene in many tumours, but it has been little studied in pituitary adenomas and the mechanism is not well understood. The purpose of this study was to investigate the function of MDM2 and its primary mechanism of action in pituitary adenoma cells.
The expression of MDM2 in pituitary adenoma cell lines and normal cells was determined by real-time polymerase chain reaction (RT-PCR). The proliferation and apoptosis of pituitary adenoma cells after inhibition of MDM2 expression were detected by MTS and flow cytometry, respectively. The protein expressions of MDM2 and p53 were detected by western blot. Co-IP was used to detect the direct binding between MDM2 and p53.
The results of RT-PCR showed that MDM2 was significantly up-regulated in pituitary adenoma cell lines. Inhibition of MDM2 suppressed the proliferation and promoted apoptosis of pituitary adenoma cells. However, inhibiting the expression of MDM2 can promotethe protein expression of p53. The results of co-IP showed that MDM2 interacted with p53 by direct combination. Then, we inhibited the expressions of p53 and MDM2 simultaneously in the pituitary adenoma cells by co-transfecting siRNAs, and the results showed that, compared with the group that inhibited MDM2 alone, cell proliferation of the co-transfected group increased and apoptosis of the cotransfected group decreased, which was similar to the NC group.
Taken together, these results suggest that MDM2 promoted the proliferation and inhibited the apoptosis of pituitary adenoma cells by directly interacting with p53 in pituitary adenoma cells. Therefore, MDM2-p53 may serve as a novel marker and therapeutic target for pituitary adenomas.
垂体腺瘤是最常见的颅内肿瘤之一。双微体 2 同源物（MDM2）被认为是许多肿瘤中的重要癌基因，但在垂体腺瘤中研究较少，其机制尚不清楚。本研究旨在探讨 MDM2 在垂体腺瘤细胞中的功能及其主要作用机制。
通过实时聚合酶链反应（RT-PCR）检测垂体腺瘤细胞系和正常细胞中 MDM2 的表达。通过 MTS 和流式细胞术分别检测抑制 MDM2 表达后垂体腺瘤细胞的增殖和凋亡。通过 Western blot 检测 MDM2 和 p53 的蛋白表达。用 co-IP 检测 MDM2 和 p53 之间的直接结合。
RT-PCR 结果显示，MDM2 在垂体腺瘤细胞系中显著上调。抑制 MDM2 抑制了垂体腺瘤细胞的增殖并促进了其凋亡。然而，抑制 MDM2 的表达可促进 p53 的蛋白表达。co-IP 的结果表明，MDM2 通过直接结合与 p53 相互作用。然后，我们通过共转染 siRNAs 同时抑制垂体腺瘤细胞中 p53 和 MDM2 的表达，结果表明，与单独抑制 MDM2 的组相比，共转染组的细胞增殖增加，凋亡减少，与 NC 组相似。
综上所述，这些结果表明，MDM2 通过与垂体腺瘤细胞中的 p53 直接相互作用，促进了垂体腺瘤细胞的增殖并抑制了其凋亡。因此，MDM2-p53 可能成为垂体腺瘤的一个新的标志物和治疗靶点。
