Overcoming Hypoxic Resistance in Non-Small Cell Lung Cancer By Targeting Mitochondrial Metabolism

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PROJECT SUMMARY Many groups are investigating why some lung cancer patients respond well to radio- and immuno-therapies and some do not. One variable is tumor hypoxia, and many groups have shown it can significantly inhibit the effectiveness to these therapeutic modalities. Clinical studies have identified hypoxia as an independent prognostic indicator of poor patient outcomes, but even though this connection has been known for decades, no FDA-approved intervention exists to clinically overcome hypoxia. Some investigators have tried to deliver more oxygen to the tumor, but this approach remains constrained due to the poorly formed tumor vasculature. We have taken an innovative approach and asked if we can reduce demand for, rather than increase supply of, oxygen to reduce hypoxia. We have found that the FDA-approved vasorelaxant papaverine (PPV) has an off- target ability to inhibit mitochondrial complex 1, and reduce oxygen consumption rapidly, in low micromolar concentrations in every cell line tested in vitro. We have also shown that PPV can enhance the effectiveness of radiation and immune checkpoint blockade (ICB) in preclinical models of lung and other cancers, without sensitizing well-oxygenated normal tissue. Reducing hypoxia reverses immune privilege, decreases terminally- exhausted T cells, and increases progenitors that are responsive to PD-1 blockade. We have more recently developed new derivatives of PPV that have lost their vasorelaxant capability and increased their duration of action so that they can be improved immuno-sensitizers. We now propose to test the hypothesis that PPV can effectively enhance the radio- and immuno-therapeutic treatment of preclinical models of lung cancer, and that it is feasible to add PPV to standard of care therapy for advanced non-small cell lung cancer (NSCLC). We have examined TCGA databases and found that lung cancer driver mutations in the KEAP1/NRF2 pathway lead to high levels of mitochondrial gene expression that can cause elevated oxygen metabolism contributing to hypoxia. In Aim 1, we will investigate the effects of oncogenic NRF2 activation human and murine cells and model tumors to determine the dependence of these cells on mitochondrial function, how increased oxygen metabolism contributes to tumor hypoxia, and if therapy-refractory tumors are sensitized by PPV or its derivatives. In Aim 2, we will examine the effect of tumor hypoxia on the migration and activation of T-cells in model tumors and how the immune infiltrate changes after reduction of hypoxia with PPV or its derivatives. Finally, in Aim 3 we will perform a phase 1 clinical trial to determine if the addition of PPV is feasible for patients receiving standard of care chemoradiation followed by immunotherapy for advanced NSCLC. We will look for effectiveness in changing tumor oxygenation using paired blood level oxygen determination (BOLD) MRIs, and for changes in immune populations of peripheral blood mononuclear cells. These studies will let us know if, and how, to use PPV or its novel derivatives in future clinical trials for the treatment of NSCLC.