KRAS Codon-Specific Mutations Differentially Toggle PI3K Pathway Signaling and Alter Sensitivity to Inavolisib...

Area of Science:

• Oncology
• Molecular Biology
• Cancer Genetics

Background:

• PIK3CA and KRAS are frequently co-mutated oncogenes in colorectal cancer.
• Understanding KRAS mutation impact on PI3K/MAPK pathway cross-talk is crucial for targeted therapy.
• Inavolisib (GDC-0077) is a p110α-specific inhibitor targeting the PI3K pathway.

Purpose of the Study:

• To investigate how KRAS codon-specific mutations affect PI3K and MAPK pathway activity.
• To determine the differential response of colorectal cancer models with PIK3CA and KRAS co-mutations to inavolisib.
• To evaluate the synergistic potential of combining inavolisib with MAPK pathway inhibitors.

Main Methods:

• Utilized colorectal cancer models with PIK3CA and KRAS co-mutations.
• Assessed pathway activity (PI3K and MAPK) in different KRAS mutation contexts.
• Evaluated in vitro and in vivo efficacy of inavolisib as a single agent and in combination therapy.

Main Results:

• KRAS G12D-mutated cells showed greater sensitivity to inavolisib compared to KRAS G13D or other MAPK mutations.
• PI3K and MAPK pathways were active in both sensitive and less sensitive KRAS co-mutated genotypes.
• Combination therapy of inavolisib with MAPK inhibitors demonstrated synergistic effects in most co-mutated models.

Conclusions:

• Specific KRAS codon substitutions differentially modulate pathway activity and inavolisib sensitivity in colorectal cancer.
• Findings suggest that KRAS mutation type can predict response to inavolisib monotherapy versus combination therapy.
• This research informs personalized treatment strategies for patients with PIK3CA-mutated colorectal cancer harboring KRAS alterations.