Stimulatory effect of voluntary exercise or fat removal (partial lipectomy) on apoptosis in the skin of UVB light-irradiated mice.
Earlier studies indicated that high dietary fat and obesity are associated with an increased risk of cancer at several organ sites in experimental animals and in humans. In a recent study we found that voluntary running wheel exercise decreased body fat and inhibited ultraviolet B light (UVB)-induced carcinogenesis in the epidermis of SKH-1 mice. In the present study we demonstrate that voluntary running wheel exercise stimulated UVB-induced apoptosis in the epidermis by a p53-independent mechanism, and voluntary exercise also stimulated apoptosis in UVB-induced tumors in tumor-bearing mice. Exercise had no effect in non-UVB-treated epidermis or in areas of the epidermis away from tumors in tumor-bearing mice. In addition, we found that removal of the parametrial fat pads (partial lipectomy) 2 weeks before UVB irradiation enhanced UVB-induced apoptosis. The results of our studies suggest that fat cells secrete substances that inhibit apoptosis in cells with DNA damage and possibly also in tumors. Our results help explain why exercise or various dietary regimens that decrease tissue fat inhibit carcinogenesis.
Lu
Yao-Ping
YP
Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers-The State University of New Jersey, 164 Frelinghuysen Road, Piscataway, NJ 08854-8020, USA.
Lou
You-Rong
YR
Nolan
Bonnie
B
Peng
Qing-Yun
QY
Xie
Jian-Guo
JG
Wagner
George C
GC
Conney
Allan H
AH
D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D001835:Body Weight / Q000528:radiation effects; D053148:Caspase 3 / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism / Q000528:radiation effects*; D005260:Female; D015187:Lipectomy; D051379:Mice; D018345:Mice, Knockout; D010768:Phosphoserine / Q000378:metabolism; D010805:Physical Conditioning, Animal; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays
D016159:Tumor Suppressor Protein p53; D010768:Phosphoserine; D053148:Caspase 3