Submitted on March 16, 2005
Accepted on May 18, 2005
Effects of over-expression of Pancreatic-Derived Factor (FAM3B) in isolated mouse islets and insulin-secreting 
TC3 cells
Xiaopei Cao1, Jichun Yang2, Brant Burkhardt3, Zhiyong Gao2, Ryan K Wong2, Scott Greene2, Jianmei Wu2, and Bryan A Wolf2*
1 Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, PA, USA; Department of Endocrinology, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
2 Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, PA, USA
3 Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, PA, USA; Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, PA, USA
* To whom correspondence should be addressed. E-mail: wolfb{at}mail.med.upenn.edu.
PANcreatic DERived factor (PANDER, FAM3B) is a recently-discovered islet-specific cytokine. We have previously shown that in vitro truncated recombinant PANDER isoforms (20 and 21 kDa) is cytotoxic to 
-cell lines but the effects of full-length PANDER on islet biology remain unclear. In this study, we used adenovirus (Ad-PANDER) to overexpress full-length cDNA of PANDER in islets and -TC3 cells. -TC3 cells were infected with Ad-PANDER or control vector. After 48 h, cell viability was significantly decreased as evaluated by the MTT assay. The number of dead cells was significantly increased as indicated by the fluorescent intensity of the propidium iodide stained cells (160 ± 13% vs. control 100 ± 7%, P=0.001). Flow cytometric Tunel assay showed that overexpressing PANDER induced a significant 4-fold increase in -cell apoptosis (19.4 ± 6.3% vs. control 4.1 ± 0.8%, P<0.05). There was a significant increase in the number of Annexin V-positive (apoptotic) cells and propidium iodide-positive (dead) cells in mouse islets infected with Ad-PANDER compared to control cells infected with Ad-LacZ. Addition of 4 nM recombinant PANDER protein to -TC3 cells or infection of Ad-PANDER did not affect Akt and Stat1 phosphorylation, Bcl-2, Fas and NF-kB protein levels. However, activation of caspase-3 was observed in -TC3 and islets infected with Ad-PANDER. Overexpression of PANDER in mouse islets or addition of recombinant PANDER decreased insulin secretion induced by carbachol + glucose or high potassium but not that by glucose alone. Culture with recombinant PANDER did not affect glucose induced NAD(P)H elevation in mouse islets. In conclusion, Ad-PANDER infection is as effective as truncated recombinant PANDER to induce -TC3 cell and mouse islet apoptosis.
