Parathyroid hormone-related protein (PTHrP) as a causative factor of cancer-associated wasting: possible involvement of PTHrP in the repression of locomotor activity in rats bearing human tumor xenografts.
Nude rats bearing the LC-6-JCK human lung cancer xenograft displayed cancer-associated wasting syndrome in addition to humoral hypercalcemia of malignancy. In these rats, not only PTHrP but also several other human proinflammatory cytokines, such as IL-6, leukemia-inducing factor, IL-8, IL-5 and IL-11, were secreted to the bloodstream. Proinflammatory cytokines induce acute-phase reactions, as evidenced by a decrease of serum albumin and an increase in alpha1-acid glycoprotein. Tumor resection abolished the production of proinflammatory cytokines and improved acute-phase reactions, whereas anti-PTHrP antibody affected neither proinflammatory cytokine production nor acute-phase reactions. Nevertheless, tumor resection and administration of anti-PTHrP antibody similarly and markedly attenuated not only hypercalcemia but also loss of fat, muscle and body weight. Body weight gain by anti-PTHrP antibody was associated with increased food consumption; increased body weight from anti-PTHrP antibody was observed when animals were freely fed but not when they were given the same feeding as those that received only vehicle. Furthermore, nude rats bearing LC-6-JCK showed reduced locomotor activity, less eating and drinking and low blood phosphorus; and anti-PTHrP antibody restored them. Although alendronate, a bisphosphonate drug, decreased blood calcium, it affected neither locomotor activity nor serum phosphorus level. These results indicate that PTHrP represses physical activity and energy metabolism independently of hypercalcemia and proinflammatory cytokine actions and that deregulation of such physiologic activities and functions by PTHrP is at least in part involved in PTHrP-induced wasting syndrome.
Onuma
Etsuro
E
Pharmaceutical Research Department IV, Kamakura Research Laboratories, Chugai Pharmaceutical Co., Kanagawa, Japan.
Tsunenari
Toshiaki
T
Saito
Hidemi
H
Sato
Koh
K
Yamada-Okabe
Hisafumi
H
Ogata
Etsuro
E
D000230:Adenocarcinoma / Q000473:pathology* / Q000662:veterinary; D000818:Animals; D001835:Body Weight; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000662:veterinary; D016207:Cytokines / Q000097:blood / Q000378:metabolism; D004195:Disease Models, Animal; D004734:Energy Metabolism; D005247:Feeding Behavior; D006801:Humans; D006934:Hypercalcemia / Q000150:complications / Q000503:physiopathology / Q000662:veterinary; D007680:Kidney Neoplasms / Q000473:pathology* / Q000662:veterinary; D007822:Laryngeal Neoplasms / Q000473:pathology* / Q000662:veterinary; D008175:Lung Neoplasms / Q000473:pathology* / Q000662:veterinary; D009043:Motor Activity; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000662:veterinary; D044162:Parathyroid Hormone-Related Protein / Q000502:physiology*; D051381:Rats; D011923:Rats, Nude; D014183:Transplantation, Heterologous; D019282:Wasting Syndrome / Q000503:physiopathology* / Q000662:veterinary
D016207:Cytokines; D044162:Parathyroid Hormone-Related Protein