In vitro and in vivo investigation of the mechanisms of resistance to anti-KRAS therapies in pancreatic tumors

• Grant number: 24/13580-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: July 01, 2025
• End date: November 30, 2027
• Field of knowledge: Biological Sciences - Pharmacology - Biochemical and Molecular Pharmacology
• Principal Investigator: Renato José da Silva Oliveira
• Grantee: Abu-Bakr Adetayo Ariwoola
• Host Institution: Hospital do Câncer de Barretos. Fundação Pio XII (FP). Barretos , SP, Brazil

Abstract

The RAS gene family, comprising KRAS, NRAS, and HRAS, is the most frequently mutated in cancers, with KRAS mutations accounting for approximately 75% of these cases. These mutations play a crucial role in the development of lung, colorectal, and pancreatic cancers, all of which have high mortality rates, prompting a decades-long search for effective KRAS protein inhibitors. However, due to the protein's structural complexity and other factors, this task was long considered impossible. The identification of "druggable" sites in some KRAS variants has recently enabled the design of more potent, selective inhibitors with better bioavailability, such as MRTX1133 for the KRAS-G12D variant. Unfortunately, reports in the literature have described cases of acquired resistance and subsequent failure to respond to anti-KRAS therapies. Therefore, this project aims to investigate, using a pre-clinical approach, the molecular alterations that lead to resistance to MRTX1133, seeking a therapeutic solution to this challenge. The project will be divided into three stages: (1) Creation of resistance models to the KRAS inhibitor; (2) Identification of resistance markers to anti-KRAS therapy; (3) Evaluation of therapeutic combinations capable of restoring sensitivity to the KRAS inhibitor. To this end, four tumor cell lines, mutant for KRAS-G12D, will be continuously exposed to the inhibitor MRTX1133 to generate resistant clones, while molecular changes in gene expression profiles related to proliferation and immune response pathways will be analyzed through RNA sequencing. Additionally, the differential expression of proteins between resistant and sensitive clones will be evaluated in relation to KRAS-mediated signaling pathways and immune responses using reverse phase protein arrays (RPPA). Finally, proposals for therapeutic combinations to overcome resistance to KRAS inhibitors will be developed, and the efficacy of these combinations will be assessed through cellular assays of proliferation, invasion, migration, colony formation, cell cycle analysis, and cell death, using 2D, 3D, and xenograft cell models. It is hoped that this pre-clinical research platform will identify biomarkers related to anti-KRAS therapy failures and, simultaneously, demonstrate the best therapeutic combinations for controlling the KRAS oncogene in patients who, after failing KRAS inhibitors, have no treatment options. (AU)