Effects of 3'-(3-cyano-4-morpholinyl)-3'-deaminoadriamycin and structural analogues on DNA in HT-29 human colon carcinoma cells.
The potent Adriamycin (ADR) analogue, 3'-(3-cyano-4-morpholinyl)-3'-deaminoadriamycin (CMA), produces DNA-DNA cross-links in human and murine tumor cells. The cellular pharmacology of CMA, its derivative, 5-imino-3'-(3-cyano-4-morpholinyl)-3'-deaminoadriamycin (ICMA), 3'-(4-morpholinyl)-3'-deaminoadriamycin (MA), and ADR was evaluated in HT-29 human colon carcinoma cells to determine the structural requirements for the cross-linking activity of CMA, and the role of this activity in the antitumor effect of this agent. CMA was 50-fold more cytocidal than ICMA to HT-29 cells, 300-fold more toxic than MA, and 150-fold more potent than ADR. Both CMA and ICMA produced DNA-DNA cross-links in HT-29 cells but, consistent with its reduced cytotoxicity, the imino derivative was 30-fold less active than CMA. No DNA-DNA cross-links were observed with MA or ADR. CMA also showed cross-linking activity in isolated HT-29 nuclei, indicating that cytoplasmic activation was not required for this effect. Both CMA and ICMA produced cross-links in isolated lambda-phage DNA with CMA being 40-fold more active than the imino derivative, and this activity was unchanged in the presence or absence of a reducing agent. While MA and ADR produced DNA strand breaks in HT-29 cells, this damage was not observed with CMA and ICMA. This study indicates that the potent antitumor activity of CMA may be related to its ability to induce DNA cross-links, which can occur without the need for metabolic activation. The cyanide group appears to be essential for cross-linking and the quinone group may also be involved, but by a mechanism unrelated to its reduction.
Jesson
M I
MI
Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Canada.
Johnston
J B
JB
Anhalt
C D
CD
Begleiter
A
A
D000970:Antineoplastic Agents / Q000494:pharmacology*; D002460:Cell Line; D003110:Colonic Neoplasms; D004273:DNA, Neoplasm / Q000187:drug effects*; D004317:Doxorubicin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D009025:Morpholines / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D009025:Morpholines; D004317:Doxorubicin; C038555:3'-deamino-3'-(3-cyano-4-morpholinyl)doxorubicin