Abstract 4841: Molecular targets of NOSH-naproxen (AVT-219), a dual nitric oxide and hydrogen sulfide-releasing hybrid, in a xenograft mouse model of colon cancer

Introduction: Long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) may prevent colon cancer, but can cause serious gastrointestinal (GI), cardiovascular (CV), and renal side effects. Naproxen has a relatively favorable CV profile, but is notorious for its GI toxicity. To improve its safety profile, we developed NOSH-naproxen, where we linked nitric oxide (NO) and hydrogen sulfide (H2S) releasing moieties to the native molecule, the rational being the observations that NO and H2S may modulate some components of the local mucosal defense systems which should lead to reduced GI toxicity. Indeed, we recently reported that NOSH-naproxen displayed enhanced GI safety, with potent anti-inflammatory, analgesic, anti-pyretic, and anti-platelet properties. Here we describe the effects of NOSH-naproxen on the growth properties of several human colon cancer cell lines, and on its molecular targets in a xenograft mouse model of colon cancer. Methods: NOSH-naproxen was synthesized by us with 1H-NMR verification. Colon cancer cell lines: HT-29, HCT 15, and SW480; Cell growth: MTT. Xenografts: Male athymic nude (NU/NU) mice (N = 15) were implanted s.c. in the right flank with SW480 cells, when the tumors reached an average sizes of ∼100 mm3, the mice were randomly divided into 3 groups and gavaged daily with either vehicle (0.5% CMC) or equimolar concentrations of NOSH-naproxen (100 mg/kg) or naproxen (45 mg/kg). Tumor volume was measured every three days; after 30 days the mice were sacrificed, tumors collected, weighed, photographed and stored in formalin for IHC studies. Results: NOSH-naproxen inhibited the growth of HT-29, HCT 15, and SW480 cells with IC50 values of 90 ± 10, 100 ± 8, and 98 ± 7 nM at 24 hr, respectively. The corresponding IC50s for naproxen were 2800 ± 165, 2950 ± 215, and 3110 ± 185 nM. This represents an enhanced potency of ∼30,000-fold in the 3 cell lines at 24 h. In xenografts, all the mice treated with naproxen died within 2 weeks from what appeared to be GI bleeding. However, the NOSH-naproxen treated mice did not show any overt signs of toxicity. At sacrifice, NOSH-naproxen-treated mice had a mean reduction in tumor volume of 82%, and a mean reduction in tumor mass of 55%. NOSH-naproxen inhibited growth of these cancer cell xenografts as a result of reduced proliferation (decreased PCNA expression), and induction of apoptosis (increased number of TUNEL positive cells). NF-eB, activated in untreated xenografts was significantly inhibited by NOSH-naproxen. Other molecular targets affected by NOSH-naproxen were: induction of iNOS, significant reduction in FoxM1, and increases in p53. Conclusions: NOSH-naproxen is more potent and efficacious than naproxen and appears to be significantly safer. It targets parameters important in determining cellular kinetics, inflammation, and signaling pathways important in the carcinogenic process. Citation Format: Pascale L. Duvalsaint, Mitali Chattopadhyay, Ravinder Kodela, Khosrow Kashfi. Molecular targets of NOSH-naproxen (AVT-219), a dual nitric oxide and hydrogen sulfide-releasing hybrid, in a xenograft mouse model of colon cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4841.