Related Experiment Video

Updated: Jul 18, 2025

Characterize Disease-related Mutants of RAF Family Kinases by Using a Set of Practical and Feasible Methods
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Characterize Disease-related Mutants of RAF Family Kinases by Using a Set of Practical and Feasible Methods

Published on: July 17, 2019

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A Combination of Conformation-Specific RAF Inhibitors Overcome Drug Resistance Brought about by RAF Overexpression

Hiroaki Imoto1, Nora Rauch1, Ashish J Neve1

  • 1Systems Biology Ireland, School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland.

Biomolecules
|August 26, 2023
PubMed

Insights

Cancer cells can resist targeted therapies by increasing RAF proteins, reactivating the MAPK pathway. Combining two RAF inhibitors effectively blocks this resistance mechanism.

Area of Science:

  • Oncology
  • Molecular Biology
  • Pharmacology

Background:

  • Adaptive resistance to targeted cancer therapies is a significant clinical challenge.
  • The molecular mechanisms driving pathway reactivation, particularly the RAS/RAF/MEK/ERK (MAPK) pathway, are not fully understood.

Purpose of the Study:

  • To investigate a novel mechanism of MAPK pathway reactivation via RAF isoform (RAFs) upregulation.
  • To explore how RAF abundance influences paradoxical pathway activation by RAF inhibitors.
  • To evaluate combination therapy strategies against RAF-mediated adaptive resistance.

Main Methods:

  • Computational modeling to simulate pathway dynamics.
  • In vitro experiments to validate computational predictions.
  • Analysis of RAF isoform abundance and signaling output.

Main Results:

  • RAF upregulation alters the concentration range for paradoxical MAPK pathway activation.
  • Overexpression of one RAF isoform compensates for the loss or downregulation of another.
  • Single RAF inhibitors are insufficient to block ERK reactivation caused by RAF overexpression.

Conclusions:

  • RAF isoform abundance is a critical factor in adaptive resistance to MAPK-targeted therapies.
  • Combination therapy with two distinct RAF inhibitors synergistically overcomes RAF-mediated resistance.
  • Targeting RAF abundance represents a potential strategy to enhance cancer treatment efficacy.
Keywords:
ARAF knockoutMAP KinasesRAF dimerizationRAF inhibitor resistanceRAF isoformsstructure-based mechanistic modeling

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