The metabolic reprogramming of tumor cells plays a critical role in cancer progression, contributing to drug resistance and tumor survival. Tyrosine kinase inhibitors (TKIs) have shown promising clinical results by targeting specific signaling pathways involved in cancer cell proliferation, survival, and metastasis. However, the development of resistance to TKIs remains a significant challenge in oncology for the onset of multiple secondary resistance mechanisms. In parallel, dichloroacetate (DCA), a small molecule that alters cancer cell metabolism by inhibiting pyruvate dehydrogenase kinase (PDK), has been investigated for its potential to reverse the Warburg effect and reprogram tumor cell metabolism. Here, we explored the rationale behind combining TKIs with DCA, focusing on the synergistic effects that may arise from the dual inhibition of oncogenic signaling and metabolic reprogramming.

We selected three NSCLC cell line models (H1975, H1993, A549) and determined the optimal DCA dose to reverse the Warburg effect. Consequently, EGFR-mutant H1975, c-MET amplified H1993 and KRAS-mutant A549 NSCLC cells, were treated with TKIs (osimertinib, crizotinib and selumetinib, respectively), DCA alone or in combination with TKIs (halved dose). Several assays were performed to evaluate the combination effect on tumor response.

Our results highlighted that a very low dose of DCA is necessary to restore oxidative phosphorylation. The proposed combined approach, compared to TKI alone, led to a shift from glycolysis to oxidative phosphorylation, data confirmed by input (glucose) and output (ATP) levels and also by a metabolomic analysis. Moreover, a significant decrease in cell proliferation was observed in combo conditions compared to TKI and to untreated cells. On the other hand, a relevant increase of apoptosis, due to a higher BIM expression levels associated to a decrease of mitochondrial membrane potential, and autophagy was also observed. In addition to these findings, all cell lines treated showed a reduced migration and invasion ability due to the slower wound closure and the reduced protrusion in a 2D and 3D cell culture assay, respectively.

Our findings indicate that the combination of TKIs and DCA, at low doses, represents a promising therapeutic approach to overcome resistance and improve clinical outcomes in target cancer therapy.