Despite incremental progress in the treatment of pancreatic adenocarcinoma, the prognosis of patients remains poor. Here, we report the preclinical studies in pancreatic cancer cells that demonstrate the efficacy of triphendiol (NV-196, a synthetic isoflavene) both as a monotherapy and as a gemcitabine sensitizer. The in-vitro effects of triphendiol on the pancreatic cancer cell lines HPAC and MIAPaCa-2 were determined using cell proliferation, flow cytometry, and western blot analysis. The antiproliferative activity of triphendiol was also investigated in two xenograft models of pancreatic cancer (HPAC and MIAPaCa-2). As a monotherapy, triphendiol-inhibited cell proliferation-induced p53-independent G2/M cell cycle arrest and activation of the intrinsic (mitochondrial) apoptosis pathway. Triphendiol-induced apoptosis was caspase independent and death receptor independent, whereas cell necrosis was caspase mediated. Using combination index analysis, we have shown that pretreatment of pancreatic cancer cells with triphendiol enhanced the cytotoxic effect of gemcitabine, the standard of care used to treat advanced pancreatic cancer. In xenograft models of pancreatic cancer, the rate of tumor proliferation on mice coadministered with triphendiol and gemcitabine was significantly reduced when compared with the corresponding tumor proliferation rates from the respective monotherapy-control and vehicle-control groups. Triphendiol was recently granted Investigational New Drug status by the US Food and Drug Administration. These data justify the commencement of clinical studies investigating the utility of combining triphendiol and gemcitabine in patients with early-stage and late-stage pancreatic cancer.
aDepartment of Surgery, U.A.B. Medical Center, Birmingham, Alabama
bDepartments of Obstetrics and Gynecology
cMedical Oncology, Yale University School of Medicine, New Haven, Connecticut, USA
dMarshall Edwards Inc
eThe Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia
Correspondence to Ewan Milne Tytler, PhD, Department of Surgery, U.A.B. Medical Center, Birmingham, Alabama 35294, USA Tel: +205 934 5747; fax: +205 975 7549; e-mail: ewan.tytler@ccc.uab.edu; ewantyt@email.phoenix.edu
Present address: Ewan Milne Tytler, PhD, University of Phoenix, Birmingham Campus, College of Arts and Science, 100 Corporate Parkway, Suite 250, AL 35242, Birmingham
Present address: M. Wasif Saif, MD, Milstein Hospital, Division Hematology/Oncology, 177 Fort Washington Avenue, Suite 6-435, NY 10032, New York
Authors' contributions: X.W. carried out western blot analysis and drafted the manuscript; R.M. carried out cell proliferation experiments, combination index calculation, and xenograft studies; K.H.K. carried out western blot analysis; A.B.A. carried out the mitochondrial and cytoplasmic extraction and western blot analysis; A.W. carried out combination index calculation and xenograft studies; J.A.T. and G.M. participated in the design of the study and helped to draft the manuscript; M.W.S. and A.J.H. helped to draft the manuscript; D.M.B. conceived the in-vivo study, and participated in its design and coordination, performed the statistical analysis and helped to draft the manuscript; E.M.T. conceived the in-vitro study, and participated in its design and coordination, carried out FACS analysis, and also helped to draft the manuscript. All authors read and approved the final manuscript.
Received June 18, 2010
