Three aspects of this project are presently being pursued: (1) Chemical synthesis of potentially carcinogenic derivatives of 2-amino-3-methly-imidazole-[4,5-f]quinoline (IQ). These derivatives include nitro-IQ, N-hydrozy-IQ, nitroso-IQ, azoxy-IQ, azo-IQ, and acetoxy-acetamide-IQ. Purification of these compounds is achieved through recrystallization and high performance liquid chromatography (HPLC). Structure identification is confirmed by ultraviolet absorbance spectrometry and electron impact mass spectrometry. Synthesis of radiolabeled derivatives is also underway in order to facilitate detection of DNA adducts. (2) Reaction of derivatives with DNA. DNA adducts of IQ derivatives are being chemically synthesized in vitro under various reaction conditions. The extent of the reaction is being tested using various deoxynucleotides, deoxynucleoside, and polynucleotides, including calf thymus DNA. Reactivity of specific IQ derivatives, such as N-hydroxy-IQ and acetoxy-acetamide-IQ with deoxynucleotide bases are currently being examined. Adducts are initially identified by HPLC or, if necessary, with the use of radiolabeled precursors. Adducts are further identified by ultraviolet abosrbance, spectra and mass spectral analysis. (3) Mutagenicity studies. Ames Salmonella mutagenicity tests are currently underway with IQ derivatives in order to assess the ultimate mutagenic derivatives of IQ. Attempts to correlate the ability of a derivative to covalently bind to DNA with its mutagenicity will be made.
