| Summary |
Background: Tyrosine kinase inhibitors (TKIs) are widely used for treating solid and hematologic malignancies. However, their efficacy is frequently short lived, warranting the search for safe potentiation strategies. Short courses of fasting were shown to sensitize cancer cells to chemo- and radiotherapy while increasing the resistance of healthy tissues to the same agents. The purpose of this study was to assess the potential of fasting to increase the efficacy of TKIs. Methods: starvation-mimicking culture conditions were studied for their ability to potentiate the effects of Epidermal Growth Factor Receptor (EGFR), Human Epidermal Growth Factor Receptor 2 (HER2), Anaplastic Lymphoma Kinase (ALK) and multitarget TKIs in terms of cancer cell growth, signaling cascades inhibition, and changes in gene expression profile in TKI-sensitive cancer cells. In vivo, the activity of crizotinib or regorafenib, weekly cycles of fasting, or their combination was compared in tumor xenografts models. Results: In vitro, starvation-mimicking culture conditions increased the ability of TKIs to block cancer cell growth and to inhibit the mitogen-activated protein kinase (MAPK) signaling pathway. At the gene expression profile level, starvation and crizotinib led to similar changes, but their combination strengthened Rb-, MYC-, and E2F-dependent transcription inhibition. In vivo, both TKIs and cycles of fasting slowed tumor growth, but, when combined, they were significantly more effective than either type of treatment alone. Conclusions: Cycles of fasting or of specifically designed fasting-mimicking diets should be evaluated in clinical studies as a means to potentiate the activity of TKIs in clinical use. |
