Obesity, but not high-fat diet, promotes murine pancreatic cancer growth.
BACKGROUND
Obesity accelerates pancreatic cancer growth; the mechanisms underlying this association are poorly understood. This study evaluated the hypothesis that obesity, rather than high-fat diet, is responsible for accelerated pancreatic cancer growth.


METHODS
Male C57BL/6J mice were studied after 19 weeks of high-fat (60 % fat; n = 20) or low-fat (10 % fat; n = 10) diet and 5 weeks of Pan02 murine pancreatic cancer growth (flank).


RESULTS
By two-way ANOVA, diet did not (p = 0.58), but body weight, significantly influenced tumor weight (p = 0.01). Tumor weight correlated positively with body weight (R (2) = 0.562; p < 0.001). Tumors in overweight mice were twice as large as those growing in lean mice (1.2 ± 0.2 g vs. 0.6 ± .01 g, p < 0.01), had significantly fewer apoptotic cells than those in lean mice (0.8 ± 0.4 vs 2.4 ± 0.5; p < 0.05), and greater adipocyte volume (3.7 vs. 2.2 %, p < 0.05). Apoptosis (R (2) = 0.472; p = 0.008) and serum adiponectin correlated negatively with tumor weight (R = 0.45; p < 0.05).


CONCLUSIONS
These data suggest that body weight, and not high-fat diet, is responsible for accelerated murine pancreatic cancer growth observed in this model of diet-induced obesity. Decreased tumor apoptosis appears to play an important mechanistic role in this process. The concept that decreased apoptosis is potentiated by hypoadiponectinemia (seen in obesity) deserves further investigation.
Department of Surgery, Indiana University School of Medicine, 535 Barnhill Dr. RT 130, Indianapolis, IN 46202, USA.
Patrick B
PB
White
Kathryn M
KM
Ziegler
Deborah A
DA
Swartz-Basile
Sue S
SS
Wang
Keith D
KD
Lillemoe
Henry A
HA
Pitt
Nicholas J
NJ
Zyromski
D017667:Adipocytes / Q000473:pathology*; D000818:Animals; D017209:Apoptosis; D059305:Diet, High-Fat / Q000009:adverse effects*; D004195:Disease Models, Animal; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000097:blood / Q000150:complications*; D010190:Pancreatic Neoplasms / Q000097:blood / Q000150:complications* / Q000473:pathology / Q000503:physiopathology