Inhibition of histone methyltransferase PRMT5 attenuates cisplatin-induced hearing loss through the PI3K/Akt-mediated mitochondrial apoptotic pathway / 药物分析学报

This study aimed to evaluate the therapeutic potential of inhibiting protein arginine methyltransferase 5(PRMT5)in cisplatin-induced hearing loss.The effects of PRMT5 inhibition on cisplatin-induced auditory injury were determined using immunohistochemistry,apoptosis assays,and auditory brainstem response.The mechanism of PRMT5 inhibition on hair cell survival was assessed using RNA-seq and Cleavage Under Targets and Tagment-quantitative polymerase chain reaction(CUT&Tag-qPCR)analyses in the HEI-OC1 cell line.Pharmacological inhibition of PRMT5 significantly alleviated cisplatin-induced damage to hair cells and spiral ganglion neurons in the cochlea and decreased apoptosis by protecting mitochondrial function and preventing the accumulation of reactive oxygen species.CUT&Tag-qPCR analysis demonstrated that inhibition of PRMT5 in HEI-OC1 cells reduced the accumulation of H4R3me2s/H3R8me2s marks at the promoter region of the Pik3ca gene,thus activating the expression of Pik3ca.These findings suggest that PRMT5 inhibitors have strong potential as agents against cisplatin-induced ototoxicity and can lay the foundation for further research on treatment strategies of hearing loss.

Expression of PRMT5 protein in colorectal cancer tissues and its relationship with recurrence after radical resection / 中国医师进修杂志

Objective:To investigate the expression of PRMT5 protein in colorectal cancer tissues and its relationship with recurrence after curative resection.Methods:The clinical data of 154 patients with colorectal cancer who underwent radical resection in Zigong Fourth People′s Hospital from February 2016 to April 2018 were retrospectively reviewed, the colorectal cancer tissues and adjacent tissues samples of them were retained at the time of surgery. The PRMT5 protein expressions in each specimen were determined by immunohistochemistry. The recurrence status of patients during the 3-year postoperative follow-up period was counted, and they were divided into recurrence group and no recurrence group.The positive expression rates of PRMT5 protein in colorectal cancer tissues between the two group was compared, and Cox regression model analysis was used to analyze the influencing factors of recurrence after radical resection of colorectal cancer.Results:The positive expression rate of PRMT5 protein in the colorectal cancer tissues was higher than that in the adjacent tissues: 70.13%(108/154) vs. 16.23%(25/154), there was statistical difference ( χ2 = 91.16, P<0.01). Within 3 years after surgery, the recurrence rate was 20.13%(31/154), and the positive expression rate of PRMT5 protein in the recurrence group was higher than that in the no recurrence group: 93.55%(29/31) vs. 64.23%(79/123), there was statistical difference ( χ2 = 10.16, P<0.05). The results of Cox regression model analysis showed that the tumor stage, lymph node metastasis and positive expression of PRMT5 protein in colorectal cancer tissues were independent risk factors for recurrence after radical resection of colorectal cancer ( P<0.05). Conclusions:The PRMT5 protein shows high expression in colorectal cancer tissues, and it is closely related to postoperative recurrence, and its positive expression can increase the risk of postoperative recurrence in patients with colorectal cancer.

Effect of PRMT5 Expression Knockdown on Proliferation, Invasion and Apoptosis of Gastric Cancer Cells and Its Mechanism / 肿瘤防治研究

Objective To observe the expression level of PRMT5 in gastric cancer cells, and explore the effect of knocking down the expression level of PRMT5 on the biological behavior of gastric cancer cells. Methods Western blot was used to detect the expression of PRMT5 protein in gastric cancer cell lines MGC803, SGC7901, MKN45 and human gastric epithelial cells GES-1. siRNA1 and siRNA2 plasmids were transfected to knock down the expression of PRMT5. Cell proliferation and apoptosis assay, transwell assay were used to detect cell proliferation, apoptosis and invasion abilities, respectively. The protein expression levels of β-catenin, cyclin D1 and Bax were detected. Results Compared with GES-1 cells, PRMT5 protein expression levels increased in MGC803, SGC7901 and MKN45 cells (P < 0.001). After knocking down the expression of PRMT5, the cell proliferation and invasion abilities were weakened, the apoptosis rate increased (P < 0.05), the expression of β-catenin and Cyclin D1 protein decreased, and the expression of Bax protein increased (P < 0.001). Conclusion The expression level of PRMT5 is increased in gastric cancer cells. Knockdown of PRMT5 expression level could inhibit cell proliferation, invasion and promote cell apoptosis via reducing Wnt/β-catenin signaling pathway.

Research progress of protein arginine methyltransferase 5 inhibitors / 中国药科大学学报

@#Protein arginine methyltransferases, which proceed the post-translational modification of both histones and non-histones, play an important role in many biological pathways. Protein arginine methyltransferase 5 (PRMT5) is a major enzyme responsible for symmetric di-methylation of arginine residues and has been suggested as a potential therapeutic target for tumors.In the past decade,the discovery and development of PRMT5 inhibitors have become one of the most important research fields.This article introduces the structure and biochemical function of PRMT5 and its correlation with cancer reviews, the binding modes and biological data of PRMT5 inhibitors under development, and discusses the clinical application potential of PRMT5 inhibitors in the treatment of cancer.

Design, synthesis and activity evaluation of protein arginine methyltransferase 5 inhibitor / 药学学报

Protein arginine methyltransferase 5 (PRMT5) is an important type II human methyltransferase. It catalyzes the symmetrical double-methylation of many histones and non-histones, and it is highly expressed in many kinds of tumors. PRMT5 has been proven to be a potential new target for cancer treatment. Based on the reported crystal complex of EPZ015666 with PRMT5, a series of new compounds was designed using GSK3326595 (EPZ015938) as the lead compound and using the conformational restriction approach. We found that compounds B8 and the C series of derivatives displayed enzyme inhibitory activity comparable to that of GSK3326595. Compounds C3 and C4 showed poor permeability in Caco-2 cells, and that might be one of the reasons for their poor anti-proliferative activity against Z-138 cells. These data provide insights for further structural optimization.

Roles of protein arginine methyltransferase 5 in cancerand its clinical application / 中国肿瘤生物治疗杂志

@#[摘 要] 蛋白质精氨酸甲基转移酶5（protein arginine methyltransferase 5，PRMT5）是一种Ⅱ型蛋白质精氨酸甲基转移酶，在胃 癌、肝癌、结直肠癌、肺癌和乳腺癌等多种肿瘤中异常表达。异常表达的PRMT5通过调节细胞周期蛋白、 PI3K细胞信号通路等途 径影响肿瘤细胞，通过对相关肿瘤抑制基因的调控进而影响肿瘤的发生和发展。本文围绕近年来肿瘤中PRMT5的最新研究进 展，包括对雄激素受体、免疫细胞、 E2F-1-Bcl-2途径、PTEN和P16等的作用及其机制，并结合目前相关抑制剂的研究，讨论如何在 未来临床治疗中靶向PRMT5达到治疗肿瘤的目的。

Study on Biological Activity of Various Truncations of Human PRMT5 in E.coli / 生物化学与生物物理进展

Protein arginine methyltransferase 5 (PRMT5) has been implicated as an important regulator of many cellular processes and signaling pathways,including chromatin remodeling,RNA splicing,DNA transcription,and cell proliferation.Therefore,structural and functional studies on PRMT5 are quite important.The full length ofPRMT5 gene was cloned into vector pGEX-4T-1,resulting in only low expression levels in Escherichia coli (E.colO.Here,it was showed that the several N-terminal amino acids deletions could result in a significant increase in the amount of soluble ft"action,while one of them did not affect the protein-arginine methyltransferase activity.And it was also found that the N-terminal 15 amino acids region of PRMT5 may be important for the catalytic activity.