title: Inhibition of malignant cell proliferation by culture media conditioned by cardiac or skeletal muscle.
abstract: The present work is an attempt to explain the high resistance of muscles to cancer development. We used primary cultures of rat skeletal and cardiac muscle, and examined the effect of the supernatant of these cultures (conditioned medium; CM) on proliferation of cancer cells. The results demonstrated that CM inhibited the proliferation of several types of malignant cells by more than 50%, without a significant inhibition on normal cells. Cell cycle analysis revealed that CM increased the number of cells in S and G2 phases, suggesting a cytostatic effect of CM. For defining the biological properties of the factor(s) which are present in the CM, skeletal muscle cultures were grown in chemically defined medium (serum free medium). The concentrated sample was applied to a Sephadex G-50 column and three fractions were obtained. Only one fraction showed inhibitory activity. Four protein bands were observed in this fraction, as revealed by SDS-PAGE. We suggest that some, or all of these proteins are responsible for inhibition of tumor cell replication.
authors.affiliation: The Otto Meyerhoff Drug Receptor Center, Bar-Ilan University, Ramat Gan, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Zinman
authors.forename: S
authors.initials: S
authors.lastname: Salzberg
authors.forename: Z
authors.initials: Z
authors.lastname: Malik
authors.forename: A
authors.initials: A
authors.lastname: Shainberg
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005434:Flow Cytometry; D006133:Growth Substances / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D008855:Microscopy, Electron, Scanning; D009124:Muscle Proteins / Q000378:metabolism / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D009369:Neoplasms / Q000473:pathology*; D051381:Rats; D015203:Reproducibility of Results; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D017077:Culture Media, Conditioned; D006133:Growth Substances; D009124:Muscle Proteins