Anti-NOSTRIN monoclonal antibody Made to order

Significance: Pancreatic tumors express high level of nitric oxide synthases (NOSs) in particular inducible (iNOS/NOS2) and endothelial (eNOS/NOS3) forms. However, the role of nitric oxide (NO center dot) in the development and progression of pancreatic cancer is not clearly defined. Delineating the NO center dot- induced signaling in pancreatic cancer and its potential contribution in disease aggressiveness may provide therapeutic targets to improve survival in this lethal malignancy. Recent Advances: An increased expression of NOS2/iNOS in tumors is associated with poorer survival in early stage resected patients with pancreatic ductal adenocarcinoma (PDAC). Furthermore, genetic deletion of NOS2 enhanced survival in mice with autochthonous PDAC. Additionally, targeting NOS3/eNOS reduced the abundance of precursor lesions in mice, which trended toward improved survival. Critical Issues: The extremely poor prognosis in pancreatic cancer is due to the late diagnosis and lack of effective therapy in advanced disease. One of the most critical issues is to decipher the underlying mechanism of disease aggressiveness and therapeutic resistance for identifying potential therapeutic target and effective treatment. Given the evidence of a strong association between inflammation and pancreatic cancer and clinical evidence, which suggests an association between NOS2 and disease aggressiveness, it is critical to define the role of NO center dot signaling in this lethal malignancy. Future Directions: Recent preclinical and clinical evidences indicate a potential therapeutic significance of targeting NO center dot signaling in pancreatic cancer. With the emergence of new preclinical models, including the patient-derived organoids, further preclinical evaluation using clinically tested NOS inhibitors is needed for designing future clinical investigation.

We recently observed that a novel, shortened variant of eNOS trafficking inducer (NOSTRIN) is expressed in cirrhotic liver. This shortened variant (NOSTRIN beta) lacks the first 78 amino acids of full-length NOSTRIN (NOSTRIN alpha) and thus a substantial part of its F-BAR domain. In contrast to NOSTRIN alpha, NOSTRIN beta mainly localizes to the cell nucleus. In this study, we show that nuclear import of NOSTRIN beta depends on two nuclear localization signals (aa 32-36: KKRK and aa 57-61: KAKKK). Each of the sequences is independently functional, but both are required to sustain nuclear localization of NOSTRIN beta. Export of NOSTRIN beta from the nucleus is facilitated by a CRM1-dependent mechanism relying on the nuclear export sequence LELEKERIQL (aa 135-145). Unlike NOSTRIN beta, the full-length variant NOSTRIN alpha was conspicuously absent from the nucleus. This is most likely because of the fact that its N-terminal F-BAR domain, which is truncated in NOSTRIN beta, facilitates association with cellular membranes. NOSTRIN beta directly binds to the 5'-regulatory region of the NOSTRIN gene (bp -200 to -1), and overexpression of NOSTRIN beta strongly decreases transcription of a reporter gene under control of this DNA region. Taken together, our results suggest that nuclear NOSTRIN beta may negatively regulate transcription of the NOSTRIN gene.