Interferon in combination with antitumourigenic phenyl derivatives: potentiation of IFN alpha activity in-vitro.
Any attempt to eradicate the heterogeneous cell population of a tumour mass would require the use of appropriate combination treatment protocols. The antitumour effects of interferon alpha (IFN alpha) in combination with AS2-1, the hydrolysis product of 3-phenylacetyl-amino-2,6-piperidinedione, were examined using several human tumour cell lines as a model. These included the malignant melanoma A375, adenocarcinoma of the prostate PC3 (hormone-insensitive bone metastasis), and the erythroleukaemia line K562. AS2-1 suppressed tumour growth through non-toxic mechanisms, with 1 mg/ml causing approximately 50% inhibition of the melanoma and prostate tumour cell proliferation. By contrast, primary normal human skin fibroblasts were significantly less sensitive to the antiproliferative effect of AS2-1. Suppression of tumour growth was seen also with AS2-1 treatment of the erythroleukaemia K562; in these cultures the drug also induced dose-dependent differentiation, as indicated by the increased haemoglobin production. Interestingly, addition of low doses of IFN alpha markedly enhanced the antitumour and differentiating effects observed with AS2-1. Treatment with 200-300 IU/ml of IFN (which caused about 20% inhibition of growth) together with 1 mg/ml of AS2-1 resulted in over 80% inhibition of the melanoma and prostate cancer cell proliferation, suggesting a synergistic activity of the two agents. This was substantiated by quantitative analysis of the differentiation induced in K562 erythroleukaemia. It appears, therefore, that IFN alpha and AS2-1 may act through synergistic mechanisms to effectively inhibit tumour growth and promote differentiation in a variety of human malignant cell lines.
Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814.
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D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004357:Drug Synergism; D005973:Glutamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D016898:Interferon-alpha / Q000494:pharmacology*; D010648:Phenylacetates / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects* / Q000473:pathology
D016898:Interferon-alpha; D010648:Phenylacetates; D005973:Glutamine; C003089:phenylacetylglutamine; C025136:phenylacetic acid