Cancers have dysfunctional redox regulation resulting in reactive oxygen species production, damaging both DNA and free dNTPs. The MTH1 protein sanitizes oxidized dNTP pools to prevent incorporation of damaged bases during DNA replication. Although MTH1 is non-essential in normal cells, we show that cancer cells require MTH1 activity to avoid incorporation of oxidized dNTPs, resulting in DNA damage and cell death. We validate MTH1 as an anticancer target in vivo and describe small molecules TH287 and TH588 as first-in-class nudix hydrolase family inhibitors that potently and selectively engage and inhibit the MTH1 protein in cells. Protein co-crystal structures demonstrate that the inhibitors bind in the active site of MTH1. The inhibitors cause incorporation of oxidized dNTPs in cancer cells, leading to DNA damage, cytotoxicity and therapeutic responses in patient-derived mouse xenografts. This study exemplifies the non-oncogene addiction concept for anticancer treatment and validates MTH1 as being cancer phenotypic lethal.

We demonstrate that in order to kill cancer cells MTH1 inhibitors must also introduce oxidized nucleotides into DNA. Furthermore, we describe TH1579 as a best-in-class MTH1 inhibitor, which we expect to be useful in order to further validate the MTH1 inhibitor concept.

Lipoxins are a group of biologically active eicosanoids typically formed by transcellular lipoxygenase activity. Lipoxin A4 (LXA4) and Lipoxin B4 (LXB4) biosynthesis has been detected in a variety of inflammatory conditions. The native lipoxins LXA4 and LXB4 demonstrate potent antiinflammatory and proresolution bioactions. However, their therapeutic potential is compromised by rapid metabolic inactivation by PG dehydrogenase-mediated oxidation and reduction. Here we report on the stereoselective synthesis of aromatic LXA4 and LXB4 analogues by employing Sharpless epoxidation, Pd-mediated Heck coupling, and diastereoselective reduction as the key transformations. Subsequent biological testing has shown that these analogues display potent biological activities. Phagocytic clearance of apoptotic leukocytes plays a critical role in the resolution of inflammation. Both LXA4 analogues (1R)-3a and (1S)-3a were found to stimulate a significant increase in phagocytosis of apoptotic polymorphonuclear leukocytes (PMN) by macrophages, with comparable efficacy to the effect of native LXA4, albeit greater potency, while the LXB4 analogue also stimulated phagocytosis with a maximum effect observed at 10-11 M. LX-stimulated phagocytosis was associated with rearrangement of the actin cytoskeleton consistent with that reported for native lipoxins. Using zymosan-induced peritonitis as a murine model of acute inflammation (1R)-3a significantly reduced PMN accumulation.