Enhancing cancer immunotherapy via inhibition of soluble epoxide hydrolase.

Cancer therapy, including immunotherapy, is inherently limited by chronic inflammation-induced tumorigenesis and toxicity within the tumor microenvironment. Thus, stimulating the resolution of inflammation may enhance immunotherapy and improve the toxicity of immune checkpoint inhibition (ICI). As epoxy-fatty acids (EpFAs) are degraded by the enzyme soluble epoxide hydrolase (sEH), the inhibition of sEH increases endogenous EpFA levels to promote the resolution of cancer-associated inflammation. Here, we demonstrate that systemic treatment with ICI induces sEH expression in multiple murine cancer models. Dietary omega-3 polyunsaturated fatty acid supplementation and pharmacologic sEH inhibition, both alone and in combination, significantly enhance anti-tumor activity of ICI in these models. Notably, pharmacological abrogation of the sEH pathway alone or in combination with ICI counter-regulates an ICI-induced pro-inflammatory and pro-tumorigenic cytokine storm. Thus, modulating endogenous EpFA levels through dietary supplementation or sEH inhibition may represent a unique strategy to enhance the anti-tumor activity of paradigm cancer therapies.

Targeting Angiogenesis via Resolution of Inflammation.

Angiogenesis, the growth of new blood vessels, plays a critical role in tissue repair and regeneration, as well as in cancer. A paradigm shift is emerging in our understanding of the resolution of inflammation as an active biochemical process with the discovery of novel endogenous specialized pro-resolving mediators (SPMs), including resolvins. Angiogenesis and the resolution of inflammation are critical interdependent processes. Disrupted inflammation resolution can accelerate tumor growth, which is angiogenesis-dependent. SPMs, including resolvins and lipoxins, inhibit physiologic and pathological angiogenesis at nanogram concentrations. The failure of resolution of inflammation is an emerging hallmark of angiogenesis-dependent diseases including arthritis, psoriasis, diabetic retinopathy, age-related macular degeneration, inflammatory bowel disease, atherosclerosis, endometriosis, Alzheimer's disease, and cancer. Whereas therapeutic angiogenesis repairs tissue damage (e.g., limb ischemia), inhibition of pathological angiogenesis suppresses tumor growth and other non-neoplastic diseases such as retinopathies. Stimulation of resolution of inflammation via pro-resolving lipid mediators promotes the repair of tissue damage and wound healing, accelerates tissue regeneration, and inhibits cancer. Here we provide an overview of the mechanisms of cross talk between angiogenesis and inflammation resolution in chronic inflammation-driven diseases. Stimulating the resolution of inflammation via pro-resolving lipid mediators has emerged as a promising new field to treat angiogenic diseases.