Related Experiment Video
Updated: Jun 20, 2026
A Method for Screening and Validation of Resistant Mutations Against Kinase Inhibitors
Published on: December 7, 2014
CRISPR Screening Identifies Mechanisms of Resistance to KRASG12C and SHP2 Inhibitor Combinations in Non-Small Cell
Anirudh Prahallad1, Andreas Weiss1, Hans Voshol1
1Novartis Institutes for BioMedical Research, Basel, Switzerland.
Abstract:
Although KRASG12C inhibitors show clinical activity in patients with KRAS G12C mutated non-small cell lung cancer (NSCLC) and other solid tumor malignancies, response is limited by multiple mechanisms of resistance. The KRASG12C inhibitor JDQ443 shows enhanced preclinical antitumor activity combined with the SHP2 inhibitor TNO155, and the combination is currently under clinical evaluation. To identify rational combination strategies that could help overcome or prevent some types of resistance, we evaluated the duration of tumor responses to JDQ443 ± TNO155, alone or combined with the PI3Kα inhibitor alpelisib and/or the cyclin-dependent kinase 4/6 inhibitor ribociclib, in xenograft models derived from a KRASG12C-mutant NSCLC line and investigated the genetic mechanisms associated with loss of response to combined KRASG12C/SHP2 inhibition. Tumor regression by single-agent JDQ443 at clinically relevant doses lasted on average 2 weeks and was increasingly extended by the double, triple, or quadruple combinations. Growth resumption was accompanied by progressively increased KRAS G12C amplification. Functional genome-wide CRISPR screening in KRASG12C-dependent NSCLC lines with distinct mutational profiles to identify adaptive mechanisms of resistance revealed sensitizing and rescuing genetic interactions with KRASG12C/SHP2 coinhibition; FGFR1 loss was the strongest sensitizer, and PTEN loss the strongest rescuer. Consistently, the antiproliferative activity of KRASG12C/SHP2 inhibition was strongly enhanced by PI3K inhibitors. Overall, KRAS G12C amplification and alterations of the MAPK/PI3K pathway were predominant mechanisms of resistance to combined KRASG12C/SHP2 inhibitors in preclinical settings. The biological nodes identified by CRISPR screening might provide additional starting points for effective combination treatments.
Significance:
Identification of resistance mechanisms to KRASG12C/SHP2 coinhibition highlights the need for additional combination therapies for lung cancer beyond on-pathway combinations and offers the basis for development of more effective combination approaches. See related commentary by Johnson and Haigis, p. 4005.
Insights
KRAS G12C inhibitors combined with SHP2 inhibitors show promise for non-small cell lung cancer (NSCLC) but resistance emerges. Combining KRAS G12C/SHP2 inhibitors with PI3K or CDK4/6 inhibitors, or targeting KRAS amplification, may overcome resistance.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Therapeutics
Background:
- KRAS G12C inhibitors demonstrate clinical activity in non-small cell lung cancer (NSCLC) and other solid tumors.
- Resistance mechanisms limit the efficacy of KRAS G12C inhibitors, necessitating combination strategies.
- Preclinical studies show enhanced antitumor activity with the KRAS G12C inhibitor JDQ443 and the SHP2 inhibitor TNO155.
Purpose of the Study:
- To identify rational combination strategies to overcome or prevent resistance to KRAS G12C/SHP2 inhibition in NSCLC.
- To investigate genetic mechanisms of resistance to combined KRAS G12C/SHP2 inhibition.
Main Methods:
- Evaluation of tumor response duration to JDQ443 ± TNO155, alpelisib, and/or ribociclib in KRAS G12C-mutant NSCLC xenograft models.
- Investigation of genetic mechanisms of resistance using genome-wide CRISPR screening.
- Analysis of KRAS G12C amplification and MAPK/PI3K pathway alterations.
Main Results:
- Combination therapies significantly extended tumor response duration compared to single-agent JDQ443.
- KRAS G12C amplification was observed with tumor growth resumption.
- FGFR1 loss sensitized, while PTEN loss rescued, KRAS G12C/SHP2 coinhibition; PI3K inhibitors enhanced antiproliferative activity.
Conclusions:
- KRAS G12C amplification and MAPK/PI3K pathway alterations are key resistance mechanisms to combined KRAS G12C/SHP2 inhibitors.
- Combination therapies involving PI3K inhibitors and targeting KRAS amplification show potential for overcoming resistance.
- CRISPR screening identified biological nodes for developing more effective combination treatments in NSCLC.
