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Updated: Jun 22, 2025
A Preclinical Murine Model of Hepatic Metastases
Published on: September 27, 2014
MLH1 Inhibits Metastatic Potential of Pancreatic Ductal Adenocarcinoma via Downregulation of GPRC5C
Wen-Jing Liu1, Jun Lu1, Wei-Xun Zhou2
1Department of General Surgery, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing, China.
Abstract:
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) sublines were established. Wound healing and transwell assays were used to evaluate cell migration/invasion. In vivo metastasis was investigated in orthotopic implantation models (severe combined immunodeficiency mice). RT-qPCR and western blotting were adopted to show gene/protein expression. MLH1 downstream genes were screened by transcriptome sequencing. Tissue microarray-based immunohistochemistry was applied to determine protein expression in human specimens. In successfully generated sublines, OE cells presented weaker migration/invasion abilities, compared with controls, whereas in KD cells, these abilities were significantly stronger. The metastasis-inhibitory effect of MLH1 was also observed in mice. Mechanistically, G protein-coupled receptor, family C, group 5, member C (GPRC5C) was a key downstream gene of MLH1 in PDAC cells. Subsequently, transient GPRC5C silencing effectively inhibited cell migration/invasion and remarkably reversed the proinvasive 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 histologic grade, vessel invasion, and poor cancer-specific survival. In conclusion, MLH1 inhibits the metastatic potential of PDAC via downregulation of GPRC5C.
Insights
The DNA mismatch repair gene MLH1 inhibits pancreatic cancer metastasis by downregulating GPRC5C. Lower MLH1 levels correlate with increased GPRC5C, promoting tumor invasion and poorer survival in pancreatic ductal adenocarcinoma (PDAC).
Area of Science:
- Oncology
- Molecular Biology
- Cancer Metastasis Research
Background:
- The role of MutL homolog-1 (MLH1) in pancreatic ductal adenocarcinoma (PDAC) metastasis is not well understood.
- MLH1, a DNA mismatch repair gene, exhibits varied effects across different cancer types.
Purpose of the Study:
- To investigate the impact of MLH1 on the metastatic potential of PDAC.
- To elucidate the molecular mechanisms by which MLH1 influences PDAC cell invasion and metastasis.
Main Methods:
- Establishment of MLH1 overexpressed (OE) and knockdowned (KD) PDAC cell lines.
- In vitro assays (wound healing, Transwell) and in vivo orthotopic implantation models in mice to assess migration, invasion, and metastasis.
- Gene and protein expression analysis using RT-qPCR, Western blotting, and transcriptome sequencing.
- Immunohistochemistry on human PDAC tissue microarrays.
Main Results:
- MLH1 overexpression reduced PDAC cell migration and invasion, while MLH1 knockdown enhanced these abilities.
- MLH1 demonstrated a metastasis-inhibitory effect in vivo.
- G protein-coupled receptor, family C, group 5, member C (GPRC5C) was identified as a key downstream target of MLH1.
- GPRC5C downregulation mimicked the anti-invasive effects of MLH1, and its silencing reversed the pro-invasive phenotype induced by MLH1 knockdown.
- Tumoral GPRC5C expression negatively correlated with MLH1 levels and positively correlated with histologic grade, vessel invasion, and poor survival in PDAC patients.
Conclusions:
- MLH1 suppresses PDAC metastatic potential primarily through the downregulation of GPRC5C.
- GPRC5C acts as a critical mediator in MLH1-driven inhibition of PDAC metastasis.
- MLH1 and GPRC5C levels serve as potential prognostic biomarkers for PDAC.
