ISSN:
1432-0843
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary 3′-Deamino-3′-(4-morpholinyl)adriamycin (MRA) and 3′-deamino-3′(3-cyano-4-morpholinyl)adriamycin (MRA-CN) were compared with adriamycin (ADR) in ADR-sensitive (P388/S) and-resistant (P388/ADR) murine leukemia cell lines with respect to cytotoxicity and cellular accumulation. MRA is only two- to threefold more cytotoxic to P388/S in culture than ADR, whereas MRA-CN is 500-fold more cytotoxic than ADR to this cell line. Yet both MRA and MRA-CN retain their potency against P388/ADR in spite of a 150-fold decrease in potency for ADR. The observed noncross-resistance of both MRA and MRA-CN in P388/ADR correlates with their increased cellular uptake and retention relative to ADR and the inability of P388/ADR to exclude these analogs as readily as it does ADR. The decreased uptake of MRA and MRA-CN in P388/ADR relative to P388/S (1.5 to 2.0-fold), the increased efflux, and the ability of verapamil to enhance cellular uptake of these analogs in P388/ADR, as it does with ADR, all indicate that the mechanism of ADR-resistance effects ADR and the morpholino analogs in a similar manner but to far different extents. The potent cytotoxicity of MRA-CN appears to be related to strong cellular interactions of the drug with macromolecules that are characterized by its nonextraction from cells by chloroform: methanol or 10 M urea and may therefore represent covalent binding.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00293986
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