DIFFERENTIAL REPAIR OF 1-(2-CHLOROETHYL)-3-(4-METHYLCYCLOHEXYL)-1-NITROSOUREA-INDUCED DNA DAMAGE IN 2 HUMAN COLON TUMOR-CELL LINES

  • 1 January 1978
    • journal article
    • research article
    • Vol. 38  (3) , 802-808
Abstract
Human colon tumor cell lines (2) were examined for their responses to 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea treatment when maintained as cultured cell lines and xenograft tumors in nude mice. One tumor line, HT, was resistant to 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea treatment both in tissue culture and in vivo. The other tumor line, BE, was sensitive to 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea treatment in vitro and in vivo. The DNA of tissue-cultured cells treated with 1-2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea was examined by alkaline elution for DNA damage. 1-2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea produced DNA strand breaks and DNA cross-links in both cell types. The DNA cross-links appeared to be completely repaired in the resistant HT line over the 48 h period following drug removal, but in the sensitive BE line little or no cross-link repair was observed during this interval.

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