Saturday, December 21, 2024
12/21/2024
Summary Despite the use of aggressive chemo-radiation therapy, children with high-risk rhabdomyosarcoma (RMS) including advanced or metastatic embryonal RMS (ERMS) with RAS mutations, have very poor outcomes (20- 30% survival at 5 years from diagnosis) with no significant improvement over the last 30 years. Further, current multimodality therapies are associated with life-long life-threatening sequelae. This project focuses on developing less-genotoxic, targeted therapy for RAS-mutant ERMS. Preliminary data support rapid translation of vertical targeting of the MAPK pathway as a therapeutic approach in ERMS. The proposed aims are based upon the following observations: (i) In RAS-driven ERMS, resistance to MEK inhibitors is a consequence of pathway reactivation through CRAF; (ii) Combination of new generation type 2 RAF inhibitors with MEK inhibitors cause dramatic regressions of most RAS-mutant ERMS PDX models but are not curative. Consequently, both intrinsic and acquired resistance will be a barrier for long-term curative outcomes; (iii) Innovative single mouse testing (SMT) experimental design shows that, consistent with their high-risk classification, RAS-mutant ERMS PDX/CDX models, rapidly fail intensive multidrug regimens used in the most recent high-risk RMS clinical protocol (ARST0431). Therefore, this project aims to: 1) define mechanisms of innate and acquired resistance to co-targeting RAF and MEK in RAS-driven ERMS with the goal to facilitate more impactful clinical outcomes. Using DNA and RNA sequencing, we will identify genomic/epigenomic changes associated with resistance and validate and define mechanisms of innate and acquired resistance to combining type 2 RAF and MEK inhibitors in ERMS; 2) evaluate how this approach can be integrated into current clinical chemotherapy protocols using the SMT experimental design. Our studies will inform biomarkers of response to type 2 RAF + MEK inhibitors combination and how this combination can be sequenced relative to chemotherapy to optimize responses of RMS PDX/CDX models, thus directly impacting clinical trials design for RAS-driven ERMS.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).