Effect of interleukin-3 and granulocyte-macrophage colony-stimulating factor on growth of xenotransplanted human tumour cell lines in nude mice.

The clonal growth of cell lines from some human solid tumours can be stimulated by haematopoietic growth factors such as recombinant human (rh) interleukin-3 (IL-3) and rh granulocyte-macrophage colony-stimulating factor (GM-CSF) in vitro. Among these cell lines are the human colorectal adenocarcinoma cell line HTB 38 and the human small-cell lung cancer cell line HTB 119. Here we report on a series of experiments studying the influence of subcutaneously administered rhIL-3 and rhGM-CSF on the in vivo growth of HTB 38 and HTB 119 cell lines as xenografts in athymic nu/nu BALB/c mice. Beginning 1 day after transplantation of the tumour the cytokines were administered daily for 20 days as a subcutaneous bolus distant from the tumour lesion at dose levels up to 1 mg/m2/day. The cytokines caused no significant and reproducible growth modulation of the tumours in vivo.