Differential action on cancer and normal tissue by adrenochrome monoaminoguanidine methanesulfonate and cytochrome C combined with radiotherapy.

PURPOSE

The possibility that radioprotective effects on potent natural killer (NK) cells by adrenochrome monoaminoguanidine methanesulfonate+cytochrome C during radiotherapy (RT) for lung cancer might result in the radiosensitization of human lung cancer cells in vivo is examined.

METHODS AND MATERIALS

Human lung cancer xenografts in the right hind legs of KSN mice (10 weeks old) were locally irradiated with 20 Gy of X ray. Adrenochrome monoaminogluanidine methanesulfonate (AMM) (10 mg/kg/day) and/or cytochrome C (CCC) (5 mg/kg/day) were given intraperitoneally immediately before or after RT, followed by daily administration for 4 days. Natural killer activities of host splenocytes were also tested with the standard 51Cr releasing assay with YAC-1 cells as target cells. In a clinical study, 65 patients with lung cancer were treated with more than 50 Gy of RT with or without combination with AMM+CCC, OK-432 or AMM+CCC+OK-432. Before and after RT, lymphocyte subsets in the peripheral blood were examined with dichromatic analysis using an Ortho Spectrum IIIFCM system and fluorescent MABs. In this study, the change in the absolute number of each subset was investigated.

RESULTS

Adrenochrome monoaminoguanidine methanesulfonate+cytochrome C augumented NK activity in KSN nude mice, protected potent NK cells in patients with lung cancer against RT and sensitized the human lung cancer xenografts to RT.

CONCLUSION

Adrenochrome monoaminoguanidine methanesulfonate+cytochrome C may have the potential as a differential modulator of radiosensitivity of normal tissues and of tumors.