The simultaneous inhibition of PI3K and AURORA A/B pathways induced a synergistic anti-tumor effect in preclinical models of NSCLC cells carrying PI3KCA mutations

Introduction: Mutations of the p110α subunit of class I phosphatidylinositol 3-kinase (PIK3CA) gene have been detected in 4-6% of lung adenocarcinoma patients (LUAD). These mutations, which typically affect the helical binding domain (exon 9, E545K, or E542K) or the catalytic subunit (exon 20, H1047R, or H1047L), are considered oncogenic and targetable. Despite their well-established oncogenic role, no therapies are currently approved. The present project aims to identify and understand the role of these mutations in activating alternative signalling pathways, and to explore targeted therapeutic options. Methods: H322 and H292 cells were transfected with plasmids carrying PIK3CA H1047R or E545K mutations. Cell growth and migration were evaluated using digital holographic microscopy- based Holomonitor and a transwell migration assay. The intracellular signaling was tested by Western blot analysis. A mid-throughput drug screening approach was used to assess the most effective drugs that can synergize with PI3K inhibitors. The drug combination was evaluated by Combenefit software analysis. The colony assay was evaluated by crystal violet. The apoptotic cells were detected using the Annexin V assay. Results: Increased growth rate and enhanced migration were observed in cells with PIK3CA mutations, accompanied by increased activity of the PI3K/Akt/mTOR pathway and the acquisition of a mesenchymal phenotype. A mid-throughput analysis drug screening approach identified the Aurora kinase inhibitor AT9283 as the most promising compound for combination with the PI3K inhibitor. Combining the PI3K and AURORA A/B inhibitors resulted in a synergistic reduction of cell proliferation, colony formation, and cell migration, and promoted apoptosis in both the H322 and H292 cell lines with H1047R and E545K mutations. Conclusions: This study demonstrated that the combination of PI3K and Aurora Kinase A/B inhibitors can be an effective strategy for treating NSCLC cells with PIK3CA mutations and could improve treatment outcomes.