Characterization of RON protein isoforms in pancreatic cancer: implications for biology and therapeutics

Area of Science:

• Oncology
• Molecular Biology
• Cancer Genetics

Background:

• The RON tyrosine kinase receptor is implicated in cancer.
• RON mutations are rare, but isoforms are prevalent in cancer cells.
• Understanding RON isoform biology is crucial for pancreatic cancer therapy.

Purpose of the Study:

• Characterize RON isoform expression in pancreatic cancer.
• Investigate mechanisms regulating RON isoform expression.
• Determine the functional impact of RON isoforms on gene expression, oncogenic phenotypes, and therapy response.

Main Methods:

• Quantification of RON transcripts in human pancreatic cancer samples.
• RNA sequencing (RNA seq) to analyze gene expression patterns induced by RON isoforms.
• Treatment with a DNA demethylating agent (5-aza-2'-deoxycytidine) to assess regulation.
• Evaluation of cell viability using RON-specific inhibitors and antibodies.

Main Results:

• RON transcript levels were 2500-fold higher in pancreatic cancer than normal pancreas, with isoforms comprising nearly 50% of total transcript.
• Ligand-independent RON isoforms (sfRON, P5P6) induced distinct gene expression profiles compared to wild-type RON.
• Promoter hypermethylation was identified as a regulatory mechanism, with 5-aza-2'-deoxycytidine decreasing RON transcripts.
• A RON-specific inhibitor reduced viability in sfRON-expressing cells, while a monoclonal antibody showed no effect.

Conclusions:

• RON isoforms constitute a significant portion of RON transcripts in pancreatic cancer and are regulated by promoter hypermethylation.
• These isoforms exhibit transforming activity, alter gene expression, and respond differently to therapies.
• Findings provide insights into RON biology and suggest therapeutic strategies targeting RON activity in pancreatic cancer.