Generation of a humanized monoclonal antibody against human parathyroid hormone-related protein and its efficacy against humoral hypercalcemia of malignancy.

Abstract

A humanized monoclonal antibody against parathyroid hormone-related protein (PTHrP) was generated from the mouse monoclonal antibody raised against the peptide corresponding to the N-terminal 34 amino acids of the human PTHrP [(PTHrP(1-34)]. The humanized antibody interacted with the PTHrP(1-34) with a kD value of 1.90 x 10(-10) M, and the epitope resides between the amino acids 20 and 30 of the PTHrP. PTHrP(1-34) significantly increased the intracellular cAMP levels in the rat osteosarcoma cells that expressed PTHR1, and the 5 microg/mL or higher concentrations of the humanized antibody almost completely blocked the PTHrP-induced cAMP production even in the presence of 2 microg/mL PTHrP(1-34), demonstrating its ability to fully neutralize PTHrP function. There was no significant difference in the potency of the mouse, chimera, or the humanized antibodies to suppress the PTHrP-induced increase in the intracellular cAMP in ROS cells. Furthermore, at the same doses, the administration of the chimera or the humanized antibody was equally effective in reducing the blood ionized calcium levels of hypercalcemic mice bearing the PAN-7-JCK human pancreatic cancer xenograft or the LC-6-JCK human lung cancer xenograft that secreted PTHrP. Thus, humanized anti-PTHrP may be useful for the treatment of the humoral hypercalcemia of malignancy in humans.

• Authors: Etsuro Onuma, Koh Sato, Hidemi Saito, Toshiaki Tsunenari, Kimie Ishii, Keiko Esaki, Naohiro Yabuta, Yuji Wakahara, Hisafumi Yamada-Okabe, Etsuro Ogata
• Journal: Anticancer research (Anticancer Res) 2004 Sep-Oct Vol. 24 Issue 5A Pg. 2665-73 ISSN: 0250-7005 [Print] Greece
• PMID: 15517871 (Publication Type: Journal Article)

Chemical References

• Antibodies, Monoclonal
• Immunoglobulin Heavy Chains
• Immunoglobulin Light Chains
• Parathyroid Hormone-Related Protein
• Peptide Fragments
• Recombinant Fusion Proteins
• parathyroid hormone-related protein (1-34)

Topics

• Amino Acid Sequence
• Animals
• Antibodies, Monoclonal (biosynthesis, genetics, immunology, pharmacology)
• Cell Line, Tumor
• Humans
• Hypercalcemia (blood, etiology, therapy)
• Immunoglobulin Heavy Chains (genetics)
• Immunoglobulin Light Chains (genetics)
• Lung Neoplasms (blood, complications)
• Male
• Mice
• Mice, Inbred BALB C
• Mice, Nude
• Molecular Sequence Data
• Pancreatic Neoplasms (blood, complications)
• Parathyroid Hormone-Related Protein (antagonists & inhibitors, immunology)
• Peptide Fragments (immunology)
• Rats
• Rats, Inbred F344
• Rats, Nude
• Recombinant Fusion Proteins (biosynthesis, genetics, immunology, pharmacology)
• Xenograft Model Antitumor Assays