Squamous cell carcinomas often produce more than a single bone resorption-stimulating factor: role of interleukin-1 alpha*.
Several cultured human squamous cell carcinoma cell lines (SCC-4, SCC-12B2, SCC-12F2, EC-GI-10, and BEN) and one normal keratinocyte line (Epy-1) were investigated for the production of bone resorption-stimulating activity (BRSA). Conditioned medium (CM) from each of the six cell lines stimulated bone resorption in neonatal mouse calvariae in culture. The BRSA of SCC-12F2 and EC-GI-10 was inhibited completely by antibody to interleukin-1 alpha (IL-1 alpha), whereas the BRSA in CM from the BEN, SCC-4, SCC-12B2, and Epy-1 cell lines was only partially inhibited by anti-IL-1 alpha. Addition of indomethacin to the calvarial cultures also partially inhibited the BRSA from EC-GI-10, SCC-4, SCC-12B2, and Epy-1 cells; the BRSA from BEN and SCC-12F2 cells was inhibited completely by indomethacin. cAMP production by calvariae was determined after a 60-min incubation with CM. CM from EC-GI-10, BEN, SCC-4, and Epy-1 stimulated cAMP production by bone. Preincubation of CM from BEN, EC-GI-10, SCC-4, and Epy-1 cells with two antisera against PTH-related protein [PTHrP; one specific for two PTHrP-(1-141), the other recognizing both PTHrP-(1-40) and PTHrP-(1-141)] completely inhibited the cAMP-stimulating activity. Using specific enzyme-linked immunosorbent assays for IL-1 alpha and IL-1 beta, IL-1 alpha was measured in CM of the SCC-4, SCC-12B2, SCC-12F2, and Epy-1 cell lines. IL-1 beta was undetectable (less than 0.1 ng/ml) in CM from all cell lines. Our findings indicate that the BRSA secreted by SCC-12F2 cells can be accounted for largely or entirely by IL-1 alpha, while the activity produced by SCC-12B2 includes IL-1 alpha and another unknown factor(s). The BRSA produced by EC-GI-10, BEN, SCC-4, and Epy-1 cells includes both IL-1 alpha and PTHrP. We conclude that IL-1 alpha may be a more prevalent and biologically significant component of the BRSA produced by SCCs than previously recognized.
Nowak
R A
RA
Laboratory of Toxicology, Harvard School of Public Health, Boston, Massachusetts 02115.
Morrison
N E
NE
Goad
D L
DL
Gaffney
E V
EV
Tashjian
A H
AH
D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies; D001862:Bone Resorption; D001842:Bone and Bones / Q000187:drug effects / Q000502:physiology*; D002294:Carcinoma, Squamous Cell / Q000503:physiopathology*; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis* / Q000494:pharmacology; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology / Q000502:physiology*; D015603:Keratinocytes / Q000378:metabolism; D051379:Mice; D009924:Organ Culture Techniques; D010281:Parathyroid Hormone / Q000494:pharmacology; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments / Q000494:pharmacology; D011506:Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000378:metabolism
D000906:Antibodies; D016207:Cytokines; D007375:Interleukin-1; C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments; D011506:Proteins; C025940:bone resorption factor; C066078:parathyroid hormone-related protein (1-141); D000242:Cyclic AMP; D007213:Indomethacin