In vitro activation of dacarbazine (DTIC) for a human tumor cloning system.

Dacarbazine (DTIC) is an agent with clinical activity against human malignant melanoma. We have explored two methods for activating DTIC so it may be used in vitro in a human tumor cloning system. The activation of DTIC by white light was found to be a viable alternative to utilizing a microsome plus cofactor system for bioactivation. The microsome plus cofactor system itself actually caused some inhibition of tumor colony formation. Light activation of DTIC appears to be a reliable and simple method which allows testing of DTIC in an in vitro soft agar culture system.