RIT1 通过与 SMC3 和 PDS5 在肝癌中相互作用来调节有丝分裂并促进增殖。

RIT1 regulates mitosis and promotes proliferation by interacting with SMC3 and PDS5 in hepatocellular carcinoma.

机构信息

State Key Laboratory of Systems Medicine for Cancer, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200032, China.

Department of Oncology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, China.

出版信息

J Exp Clin Cancer Res. 2023 Nov 29;42(1):326. doi: 10.1186/s13046-023-02892-x.

DOI:10.1186/s13046-023-02892-x

PMID:38017479

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10685607/

Abstract

BACKGROUND

As a small G protein of Ras family, Ras-like-without-CAAX-1 (RIT1) plays a critical role in various tumors. Our previous study has demonstrated the involvement of RIT1 in promoting malignant progression of hepatocellular carcinoma (HCC). However, its underlying mechanism remains unclear.

METHODS

Gene set enrichment analysis (GSEA) was conducted in the TCGA LIHC cohort to investigate the underlying biological mechanism of RIT1. Live cell imaging, immunofluorescence (IF) and flow cytometry assays were used to verify biological function of RIT1 in HCC mitosis. Subcutaneous xenografting of human HCC cells in BALB/c nude mice was utilized to assess tumor proliferation in vivo. RNA-seq, co-immunoprecipitation (Co-IP), mass spectrometry analyses, western blot and IF assays were employed to elucidate the mechanisms by which RIT1 regulates mitosis and promotes proliferation in HCC.

RESULTS

Our findings demonstrate that RIT1 plays a crucial role in regulating mitosis in HCC. Knockdown of RIT1 disrupts cell division, leading to G2/M phase arrest, mitotic catastrophe, and apoptosis in HCC cells. SMC3 is found to interact with RIT1 and knockdown of SMC3 attenuates the proliferative effects mediated by RIT1 both in vitro and in vivo. Mechanistically, RIT1 protects and maintains SMC3 acetylation by binding to SMC3 and PDS5 during mitosis, thereby promoting rapid cell division and proliferation in HCC. Notably, we have observed an upregulation of SMC3 expression in HCC tissues, which is associated with poor patient survival and promotion of HCC cell proliferation. Furthermore, there is a significant positive correlation between the expression levels of RIT1, SMC3, and PDS5. Importantly, HCC patients with high expression of both RIT1 and SMC3 exhibit worse prognosis compared to those with high RIT1 but low SMC3 expression.

CONCLUSIONS

Our findings underscore the crucial role of RIT1 in regulating mitosis in HCC and further demonstrate its potential as a promising therapeutic target for HCC treatment.

摘要

背景

Ras 家族的小 G 蛋白 Ras-like-without-CAAX-1（RIT1）在各种肿瘤中发挥着关键作用。我们之前的研究表明，RIT1 参与促进肝细胞癌（HCC）的恶性进展。然而，其潜在机制尚不清楚。

方法

对 TCGA LIHC 队列进行基因集富集分析（GSEA），以研究 RIT1 潜在的生物学机制。使用活细胞成像、免疫荧光（IF）和流式细胞术检测 RIT1 在 HCC 有丝分裂中的生物学功能。利用 BALB/c 裸鼠皮下接种人 HCC 细胞来评估体内肿瘤增殖情况。进行 RNA-seq、免疫共沉淀（Co-IP）、质谱分析、Western blot 和 IF 检测，以阐明 RIT1 调节有丝分裂和促进 HCC 增殖的机制。

结果

我们的研究结果表明，RIT1 在调节 HCC 有丝分裂中起着至关重要的作用。敲低 RIT1 会破坏细胞分裂，导致 HCC 细胞 G2/M 期阻滞、有丝分裂灾难和凋亡。发现 SMC3 与 RIT1 相互作用，敲低 SMC3 可减弱 RIT1 在体外和体内的促增殖作用。在机制上，RIT1 通过在有丝分裂过程中与 SMC3 和 PDS5 结合来保护和维持 SMC3 的乙酰化，从而促进 HCC 细胞的快速分裂和增殖。值得注意的是，我们观察到 HCC 组织中 SMC3 的表达上调，这与患者预后不良和促进 HCC 细胞增殖有关。此外，RIT1、SMC3 和 PDS5 的表达水平之间存在显著的正相关。重要的是，RIT1 和 SMC3 高表达的 HCC 患者的预后比 RIT1 高而 SMC3 低表达的患者更差。