Cardiac hormones eliminate some human squamous lung carcinomas in athymic mice.

BACKGROUND Four cardiac hormones synthesized by the same gene, i.e. atrial natriuretic peptide, vessel dilator, long acting natriuretic peptide and kaliuretic peptide, have anticancer effects in vitro. MATERIALS AND METHODS These cardiac hormones were infused subcutaneously for 28 days with weekly fresh hormones at 0.3 nM kg(-1) body weight in athymic mice bearing human squamous cell carcinomas. RESULTS Vessel dilator, atrial natriuretic peptide and kaliuretic peptide each eliminated one in six (17%) of the human squamous cell lung carcinomas. Long-acting natriuretic peptide, although it did not eliminate any of the human squamous cell lung carcinomas did decrease the volume of one carcinoma to only 2% (P < 0.0001) of the untreated carcinomas. The squamous cell lung carcinomas that were not eliminated, with the exception of the one LANP-treated tumour that decreased to only 2% of the volume of the untreated cancers, grew rapidly but their growth velocity compared to controls decreased by 76%, 40%, 38% and 25% in the vessel dilator, atrial natriuretic peptide, kaliuretic peptide and long-acting natriuretic peptide groups respectively (P < 0.05). CONCLUSIONS Three of four cardiac hormones synthesized by the atrial natriuretic peptide gene can eliminate human squamous cell lung carcinomas in athymic mice when treated subcutaneously for 4 weeks. The 4th cardiac hormone, i.e. long-acting natriuretic peptide, decreased the volume of one squamous cell lung carcinoma to 2% of that of untreated animals, suggesting that it, too, has beneficial effects on squamous cell lung cancers.