Separation of parathyroid hormone-like activity from transforming growth factor-alpha and -beta in the canine adenocarcinoma (CAC-8) model of humoral hypercalcemia of malignancy.

Abstract

A canine adenocarcinoma model (CAC-8) of humoral hypercalcemia of malignancy was evaluated for transforming growth factors (TGF)-alpha and -beta, PTH-like activity [adenylate cyclase-stimulating activity (ACSA)], and in vitro bone-resorbing activity. Biological activities present in CAC-8 were separated by reverse phase or cation exchange HPLC. TGF alpha in tumor extract was separated from TGF beta and ACSA by reverse phase HPLC. TGF alpha eluted between 26-30% acetonitrile and was identified by RIA. After the initial reverse phase separation, TGF beta and ACSA in tumor extract coeluted between 36-38% acetonitrile. Sequential cation exchange followed by reverse phase HPLC separated TGF beta from ACSA. Evaluation of fractions containing ACSA using an in vitro bone-resorbing assay demonstrated copurification of ACSA and bone-resorbing activity. The PTH receptor antagonist [Nle8,18,Tyr34]bovine PTH-(3-34)-amide, but not [Nle8,18,Tyr34]bovine PTH-(7-34)-amide, completely inhibited ACSA in column eluates. Conditioned cell culture medium from CAC-8 primary cultures contained predominantly latent TGF beta that could be activated by acidification. These findings indicate that the CAC-8 model of cancer-associated hypercalcemia produces a PTH-like factor, TGF alpha, and TGF beta that were separable by reverse phase or cation exchange HPLC. This feature should be useful to investigate the role of TGFs and PTH-like proteins in the pathogenesis of humoral hypercalcemia of malignancy.

• Authors: J I Merryman, T J Rosol, C L Brooks, C C Capen
• Journal: Endocrinology (Endocrinology) Vol. 124 Issue 5 Pg. 2456-63 (May 1989) ISSN: 0013-7227 [Print] United States
• PMID: 2539981 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Culture Media
• Neoplasm Proteins
• Parathyroid Hormone
• Receptors, Cell Surface
• Receptors, Parathyroid Hormone
• parathyroid hormone-like adenylate cyclase-stimulating protein, human
• Transforming Growth Factors

Topics

• Adenocarcinoma (complications)
• Animals
• Bone Resorption
• Culture Media
• Dogs
• Hypercalcemia (etiology, metabolism)
• Neoplasm Proteins (metabolism)
• Parathyroid Hormone (metabolism)
• Radioimmunoassay
• Receptors, Cell Surface (drug effects, physiology)
• Receptors, Parathyroid Hormone
• Transforming Growth Factors (metabolism)
• Tumor Cells, Cultured