Insulin, Leptin, and Tumoral Adipocytes Promote Murine Pancreatic Cancer Growth

Background Obesity accelerates development and growth of human pancreatic cancer. We recently reported similar findings in a novel murine model of pancreatic cancer in congenitally obese mice. The current experiments were designed to evaluate the effects of diet-induced obesity on pancreatic cancer growth. Methods Thirty C57BL/6J female mice were fed either control 10% fat ( n = 10) or 60% fat diet ( n = 20) starting at age 6 weeks. At 11 weeks, 2.5 × 10 5 PAN02 murine pancreatic cancer cells were inoculated. After 6 weeks, tumors were harvested. Serum adiponectin, leptin, insulin, and glucose concentrations were measured. Tumor proliferation, apoptosis, adipocyte content, and tumor-infiltrating lymphocytes were evaluated. Results The diet-induced obesity diet led to significant weight gain (control 21.3 ± 0.6 g; diet-induced obesity 23.1 ± 0.5 g; p = 0.03). Mice heavier than 23.1 g were considered “Overweight.” Tumors grew significantly larger in overweight (1.3 ± 0.3 g) compared to lean (0.5 ± 0.2 g; p = 0.03) mice; tumor size correlated positively with body weight ( R = 0.56; p