A nuclear budding mechanism in transiently arrested cells generates drug-sensitive and drug-resistant cells.
HCT116 (p53(+/+)) human colon carcinoma cells treated with nanomolar concentrations of doxorubicin underwent transient senescence, synthesized DNA, showed endopolyploidization, increased their size and became multinucleated without a significant increase in mitosis. Nuclei underwent a budding process that involved the release of buds outside the nuclear membrane, and some of the buds seemed to escape from the polyploid cells. A clonogenic assay showed that some cells proliferated following the initial treatment. In general, cells ensuing after budding were not resistant to a variety of drugs, although some of them turned out to be resistant, indicating a potential selective advantage. Nuclear budding was accompanied by changes in protein levels in the giant cells, including inhibition of p53 and enhanced expression of p21(WAF1) and the meiosis-related Mos. The buds might be a mechanism for the segregation and elimination of redundant DNA, or for generating viable aneuploid cells with a potentially extended life span.
Mansilla
Sylvia
S
Instituto de Biología Molecular de Barcelona, CSIC, Parc Cientific de Barcelona, Baldiri Reixach 10, E-08028 Barcelona, Spain.
Bataller
Marc
M
Portugal
José
J
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002467:Cell Nucleus / Q000187:drug effects / Q000502:physiology*; D048750:Cell Nucleus Division / Q000187:drug effects / Q000502:physiology*; D049109:Cell Proliferation / Q000187:drug effects; D016922:Cellular Senescence / Q000187:drug effects / Q000502:physiology; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000187:drug effects / Q000502:physiology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000502:physiology*; D045325:HCT116 Cells; D006801:Humans
D004317:Doxorubicin