Reactive oxygen species modulates the molecular targets of NBS‐1120 in pancreatic cancer

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BackgroundPancreatic cancer has poor survival rates and largely ineffective therapies. Aspirin is the prototypical anti‐cancer agent but its long‐term use is associated with significant side effects. NBS‐1120 belongs to a new class of “enhanced NSAIDs” that were designed to be safer alternatives by releasing nitric oxide and hydrogen sulfide. NBS‐1120 is built on an aspirin scaffold and while it retains all the classical pharmacological/therapeutic activities of aspirin, it is devoid of GI side effects. In this study, we evaluated the effects of NBS‐1120 against pancreatic cancer using cell lines and a xenograft mouse model.MethodsCell lines: MIA PaCa2 and BxPC3 human pancreatic cancer, ACBRI 515, human normal pancreatic epithelial. Cell kinetics: growth by MTT; Cell cycle phase distribution and apoptosis: Flow cytometry; Proliferation: PCNA. mRNA: qRT‐PCR. ROS: measured hydrogen peroxide and super oxide by flow cytometry, using DCFDA and DHE dyes. Xenografts: Male athymic nude mice (N=10) implanted s.c. in the right flank with MIA PaCa2 cells, after 10 days the mice were randomly divided into 2 groups (N=5/gp) and gavaged daily with NBS‐1120 (100 mg/kg) or vehicle. Tumor volume and animal wt were recorded every 3 days. After 30 days, mice were sacrificed, tumors excised, weighed, and fixed in 10% buffered formalin for IHC studies.ResultsNBS‐1120 inhibited growth of MIA PaCa‐2 and BxPC‐3 pancreatic cancer cells with IC50s of 52 ± 4, and 62 ± 5 nM, respectively, while it did not inhibit the growth of a normal pancreatic epithelial cell line at these concentrations. NBS‐1120 effects on cancer cell growth appear to be cyclo‐oxygenase (COX) independent as MIA PaCa2 cells are COX null while BxPC3 cells express both COX‐1 and COX‐2. NBS‐1120 inhibited cell proliferation, caused G0/G1 phase cycle arrest, leading to increased apoptosis. Treated cells displayed increases in reactive oxygen species (ROS) and caspase‐3 activity. In MIA PaCa‐2 cell xenografts, NBS‐1120 significantly reduced tumor growth and tumor mass, growth inhibition was due to reduced proliferation (decreased PCNA expression) and induction of apoptosis (increased TUNEL positive cells). ROS, iNOS, and p53 were increased, while NF‐κB and FoxM1 that were activated in untreated xenografts were significantly inhibited by NBS‐1120. Reduced FoxM1 protein expression was associated with reduced FoxM1 mRNA levels and increased p21 mRNA as measured by qRT‐PCR, likely explaining cell proliferative inhibition.ConclusionsNBS‐1120 preferentially affects cancer cells, targeting parameters important in determining cellular mass, and inflammation, and merits further evaluation.Support or Funding InformationSupported in part by the National Institutes of Health [R24DA018055; R01GM123508].This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.