DNA错配修复基因MutL同源物-1（MLH1）在许多癌症中具有不同的作用，然而，其对胰腺导管腺癌（PDAC）转移的影响仍不清楚。在本研究中，建立了MLH1稳定过表达（OE）和敲低（KD）亚系。使用伤口愈合和 Transwell 测定来评估细胞迁移/侵袭。在原位植入模型（SCID 小鼠）中研究了体内转移。采用RT-qPCR和蛋白质印迹法显示基因/蛋白质表达。通过转录组测序筛选MLH1下游基因。应用基于组织微阵列的免疫组织化学来测定人类样本中的蛋白质表达。在成功生成的亚系中，与对照相比，OE细胞表现出较弱的迁移/侵袭能力，而在KD细胞中，这些能力明显更强。 MLH1 的转移抑制作用也在小鼠中观察到。从机制上讲，G蛋白偶联受体C5C（GPRC5C）是PDAC细胞中MLH1的关键下游基因。随后，短暂的 GPRC5C 沉默有效抑制了细胞迁移/侵袭，并显着逆转了 KD 细胞中 MLH1 敲低的促侵袭作用。在动物模型和人类 PDAC 组织中，肿瘤 GPRC5C 表达与 MLH1 表达呈负相关，与组织学分级、血管侵袭和较差的癌症特异性生存呈正相关。总之，MLH1 通过下调 GPRC5C 抑制 PDAC 的转移潜力。版权所有 © 2024。由 Elsevier Inc. 出版。

DNA mismatch repair gene MutL homolog-1 (MLH1) has divergent effects in many cancers, however, its impact on the metastasis of pancreatic ductal adenocarcinoma (PDAC) remains unclear. In this study, MLH1 stably overexpressed (OE) and knockdowned (KD) sub-lines were established. Wound-healing and Transwell assays were used to evaluate cell migration/invasion. In vivo metastasis was investigated in orthotopic implantation models (SCID mice). RT-qPCR and western blotting were adopted to show gene/protein expression. MLH1 down-stream genes were screened by transcriptome sequencing. Tissue microarray-based immunohistochemistry was applied to determine protein expression in human specimens. In successfully generated sub-lines, OE cells presented weaker migration/invasion abilities, compared with controls, while in KD cells these abilities were significantly stronger. The metastasis-inhibitory effect of MLH1 was also observed in mice. Mechanistically, G-protein coupled receptor C5C (GPRC5C) was a key down-stream gene of MLH1 in PDAC cells. Subsequently, transient GPRC5C silencing effectively inhibited cell migration/invasion, and remarkably reversed the pro-invasive effect of MLH1 knockdown in KD cells. In animal models and human PDAC tissues, tumoral GPRC5C expression, negatively associated with MLH1 expressions, was positively correlated with histological grade, vessel invasion, and poor cancer-specific survival. In conclusion, MLH1 inhibits the metastatic potential of PDAC via down-regulation of GPRC5C.Copyright © 2024. Published by Elsevier Inc.