Overcoming resistance in lung cancer: combined mitochondrial destabilization by lipophilic cations and doxycycline in hypoxic non-small cell lung carcinoma

IntroductionLung cancer remains the leading cause of cancer-related mortality worldwide. Drug resistance is a major limitation of current therapies, prompting the search for new treatment strategies. Lung tumors frequently develop a hypoxic microenvironment associated with aggressive behavior and unfavorable clinical outcomes. Tumor-initiating cells (TICs), also known as cancer stem cells, and hypoxia-driven metabolic adaptations contribute significantly to therapy resistance. Mitochondrial destabilization has emerged as a promising invariant target in TICs. Triphenylphosphonium (TPP+)-conjugated hydroxybenzoates selectively accumulate in the mitochondrial matrix, driven by membrane potential, disrupting organelle function. Additionally, doxycycline inhibits mitochondrial biogenesis and reduces mitochondrial mass. Here, we evaluate a therapeutic strategy combining TPP+-conjugated lipophilic cations with doxycycline to target mitochondrial vulnerability in non-small cell lung cancer.MethodsTPP+ lipophilic cations conjugated to benzoate derivatives, alone or combined with doxycycline, were evaluated for their ability to disrupt mitochondrial function, reduce cell viability, and induce apoptosis in two lung cancer cell lines under normoxic and hypoxic conditions.ResultsOur results demonstrate that these compounds exhibit cytotoxicity in lung cancer cells, particularly under hypoxic conditions, consistent with mitochondrial functional impairment. Combinations of TPP+C10/doxycycline and GA-TPP+C10/doxycycline exhibited synergistic cytotoxicity in both normoxia and hypoxia, and increased apoptotic cell death compared to monotherapies.ConclusionTargeting mitochondrial functions using mitochondria-directed compounds, particularly in combination with doxycycline, represents a promising therapeutic approach for lung cancer. This strategy may be especially effective in hypoxic microenvironments, where conventional therapies often fail. Further in vivo validation is warranted to support the translational potential of this approach.