RSU-1069 is one of a group of compounds of particular interest in radiobiology, since it combines the
nitroimidazole ring with a side chain bearing a monofunctional
alkylating agent. This compound has been shown to be a potent radiosensitizer both in vitro and in vivo. Furthermore, it has recently been shown to be an effective hypoxic cell
cytotoxin in vitro. Our studies have been carried out using the SCCVII
squamous carcinoma implanted subcutaneously in C3H mice, using a technique we recently developed which facilitates isolation of
tumor cell subpopulations from known locations relative to the
tumor blood supply. The response of the separated
tumor subpopulations was assessed using a soft
agar clonogenic assay. For radiosensitization studies,
RSU-1069 was administered i.p. at 0.5 mumol/g 20 min before irradiation and the
tumors excised 20 min after irradiation. For toxicity studies,
tumors were excised 16-18 hr after
RSU-1069 administration. The results obtained to date clearly demonstrate that
RSU-1069 is an efficient hypoxic cell radiosensitizer and
cytotoxin in this murine
tumor and has little effect on well perfused (i.e., oxic) cells.