The Hunan Provincial Key Lab of Precision Diagnosis and Treatment for Gastrointestinal Tumor, Xiangya Hospital, Central South University, Changsha, Hunan, China.
Department of General Surgery, Xiangya Hospital Central South University, Changsha, Hunan Province, China.
Braz J Med Biol Res. 2024 Nov 25;57:e13985. doi: 10.1590/1414-431X2024e13985. eCollection 2024.
Gastric cancer (GC) remains a global health challenge due to its heterogeneity and diverse regional epidemiology. Treatment for advanced GC often requires chemotherapy, whose effects are closely associated with the cell cycle. This association highlights the critical need to understand cell cycle regulators that can influence the effectiveness of chemotherapy. Bioinformatics analyses were performed on transcriptome data from a hospital cohort and on a publicly available database. Flow cytometry was used for cell cycle analysis. The interaction of PMEPA1 with 14-3-3σ was confirmed by coimmunoprecipitation and immunofluorescence staining. Western blot analysis was performed following inhibition of protein synthesis and degradation to assess 14-3-3σ protein stability, while ubiquitination was evaluated after treatment with the proteasome inhibitor MG132. High PMEPA1 expression was detected in GC tissues and was correlated with poor prognosis. In vitro overexpression of PMEPA1 promoted GC cell proliferation, while knockdown of PMEPA1 inhibited cell proliferation and induced G2/M arrest. In vivo study showed that overexpressing PMEPA1 promoted tumor growth, while knocking down PMEPA1 inhibited tumor growth, as indicated by the level of the proliferation marker Ki67. 14-3-3σ was identified as a downstream target of PMEPA1. PMEPA1 binds to 14-3-3σ and promoted its degradation by facilitating its ubiquitination. Overexpression of PMEPA1 increased its interactions with TTC3 and 14-3-3σ, increased 14-3-3σ ubiquitination, and reduced 14-3-3σ stability, and the opposite effects were observed after PMEPA1 knockdown. PMEPA1 recruited TTC3, allowing the ubiquitination of 14-3-3σ and leading to its degradation, thus promoting cell cycle progression in GC.
胃癌（GC）仍然是一个全球性的健康挑战，因为它具有异质性和不同的区域流行病学。晚期 GC 的治疗通常需要化疗，其效果与细胞周期密切相关。这种关联突出表明，迫切需要了解可以影响化疗效果的细胞周期调节剂。对来自医院队列的转录组数据和公开可用的数据库进行了生物信息学分析。使用流式细胞术进行细胞周期分析。通过共免疫沉淀和免疫荧光染色证实了 PMEPA1 与 14-3-3σ 的相互作用。抑制蛋白质合成和降解后进行 Western blot 分析，以评估 14-3-3σ 蛋白稳定性，而在用蛋白酶体抑制剂 MG132 处理后评估泛素化。在 GC 组织中检测到高 PMEPA1 表达，并且与不良预后相关。体外过表达 PMEPA1 促进 GC 细胞增殖，而敲低 PMEPA1 抑制细胞增殖并诱导 G2/M 期阻滞。体内研究表明，过表达 PMEPA1 促进肿瘤生长，而敲低 PMEPA1 抑制肿瘤生长，如增殖标志物 Ki67 的水平所示。14-3-3σ 被鉴定为 PMEPA1 的下游靶标。PMEPA1 与 14-3-3σ 结合，并通过促进其泛素化来促进其降解。过表达 PMEPA1 增加了与 TTC3 和 14-3-3σ 的相互作用，增加了 14-3-3σ 的泛素化，并降低了 14-3-3σ 的稳定性，而在 PMEPA1 敲低后观察到相反的效果。PMEPA1 募集 TTC3，允许 14-3-3σ 的泛素化，并导致其降解，从而促进 GC 中的细胞周期进程。
