Phagocytosis of microspheres containing an anticancer agent by tumor cells in vitro

The uptake of suspended human albumin microspheres containing 6-mercaptopurine-8-¹⁴C by several tumor cell lines has been followed in cell culture. In a preliminary study, HeLa, KB, and human glioblastoma cells have all been shown to phagocytize the drug-containing spheres. We suggest that if studies now in progress confirm the ability of the ingested anticancer agent to survive lysosomal digestion of the albumin spheres, phagocytosis of such spheres may prove to be a method of delivering drug to malignant cells while preventing these agents from producing toxic effects in nonphagocytic tissues.