A dimeric mutant of human pancreatic ribonuclease with selective cytotoxicity toward malignant cells

Monomeric human pancreatic RNase, devoid of any biological activity other t han its RNA degrading ability, was engineered into a dimeric protein with a cytotoxic action on mouse and human tumor cells, but lacking any appreciab le toxicity on mouse and human normal cells. This dimeric variant of human pancreas RNase selectively sensitizes to apoptotic death cells derived from a human thyroid tumor. Because of its selectivity for tumor cells, and bec ause of its human origin, this protein represents a potentially very attrac tive, novel tool for anticancer therapy.