TY - JOUR
T1 - Modulation of apoptosis and enhancement of chemosensitivity by decreasing cellular thiois in a mouse B-cell lymphoma cell line that overexpresses bcl-2
AU - Story, Michael D.
AU - Meyn, Raymond E.
N1 - Funding Information:
Acknowledgements This work was supported in part by NIH grants CA69003 (REM), CA62209 (MDS), and the institutional Core Grant CA16672 from the National Cancer Institute.
Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1999
Y1 - 1999
N2 - Purpose: To determine whether the difference in the apoptosis and clonogenic survival responses to radiation observed between the murine lymphoma cell lines LY-ar, which expresses bcl-2, and LY-as, which does not, was also evident after treatment with chemotherapy agents; and to determine whether clonogenie survival after chemotherapy agent exposure could be diminished by enhancing apoptosis through a decrease in cellular thiols. Methods: Cells were treated with cisplatin, VP-16, or Adriamycin, and apoptosis was determined using a DNA fragmentation assay. Cellular survival was quantified by limiting dilution assay. Intracellular thiols were decreased by maintaining LY-ar cells in cystine/methionine-free medium (CMF medium) for 7 h after drug treatment. Results: LY-as cells were approximately four times more likely to undergo apoptosis than LY-ar cells, having differences in apoptosis of 80% and 20%, respectively, for the agents used. LY-as cells were also more sensitive as measured by cellular survival, with a dose-modifying factor of about 1.8 measured at a 10% survival level. Incubation of LY-ar cells in CMF medium after drug treatment increased apoptosis and reduced clonogenic survival to the levels seen in LY-as cells, except after treatment with VP-16, where the reduction in cell survival was more modest. Conclusions: Decreasing intracellular thiols enhances apoptosis and cell killing in lymphoma cells after exposure to a variety of chemotherapy agents. This may be especially true for tumor cells that overexpress bcl-2, a gene that modifies cellular thiol status and conveys resistance to apoptosis. In this case, decreasing cellular thiols allows killing independent of the expression of bcl-2.
AB - Purpose: To determine whether the difference in the apoptosis and clonogenic survival responses to radiation observed between the murine lymphoma cell lines LY-ar, which expresses bcl-2, and LY-as, which does not, was also evident after treatment with chemotherapy agents; and to determine whether clonogenie survival after chemotherapy agent exposure could be diminished by enhancing apoptosis through a decrease in cellular thiols. Methods: Cells were treated with cisplatin, VP-16, or Adriamycin, and apoptosis was determined using a DNA fragmentation assay. Cellular survival was quantified by limiting dilution assay. Intracellular thiols were decreased by maintaining LY-ar cells in cystine/methionine-free medium (CMF medium) for 7 h after drug treatment. Results: LY-as cells were approximately four times more likely to undergo apoptosis than LY-ar cells, having differences in apoptosis of 80% and 20%, respectively, for the agents used. LY-as cells were also more sensitive as measured by cellular survival, with a dose-modifying factor of about 1.8 measured at a 10% survival level. Incubation of LY-ar cells in CMF medium after drug treatment increased apoptosis and reduced clonogenic survival to the levels seen in LY-as cells, except after treatment with VP-16, where the reduction in cell survival was more modest. Conclusions: Decreasing intracellular thiols enhances apoptosis and cell killing in lymphoma cells after exposure to a variety of chemotherapy agents. This may be especially true for tumor cells that overexpress bcl-2, a gene that modifies cellular thiol status and conveys resistance to apoptosis. In this case, decreasing cellular thiols allows killing independent of the expression of bcl-2.
KW - Adriamycin
KW - Apoptosis
KW - Bcl-2
KW - Cisplatin
KW - Thiols
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U2 - 10.1007/s002800050990
DO - 10.1007/s002800050990
M3 - Article
C2 - 10501908
AN - SCOPUS:0032848668
SN - 0344-5704
VL - 44
SP - 362
EP - 366
JO - Cancer Chemotherapy and Pharmacology
JF - Cancer Chemotherapy and Pharmacology
IS - 5
ER -