Reconstitution of caspase 3 sensitizes MCF-7 breast cancer cells to doxorubicin- and etoposide-induced apoptosis.
MCF-7, a breast cancer-derived cell line, is deficient of caspase 3 and relatively insensitive to many chemotherapeutic agents. To study the association of caspase 3 deficiency and chemotherapeutic resistance, we reconstituted caspase 3 in MCF-7 cells and characterized their apoptotic response to doxorubicin and etoposide. Western blots demonstrated that caspase 3 was constitutively expressed in the reconstituted MCF-7 cells. Both morphological observation and survival assays showed that caspase 3 reconstitution significantly sensitized MCF-7 cells to both drugs. Remarkably increased activation of caspases 3, 6, and 7, cleavage of cellular death substrates, and DNA fragmentation were detected in the reconstituted MCF-7 cells after drug treatment. Together, these data demonstrated a specific role for caspase 3 in chemotherapy-induced apoptosis and in activation of caspases 6 and 7. Our results also suggest that caspase 3 deficiency may contribute to chemotherapeutic resistance in breast cancer.
Yang
X H
XH
Lurie Cancer Center, Northwestern University Medical School, Evanston Northwestern Healthcare, Illinois 60201, USA. x-yang1@nwu.edu
Sladek
T L
TL
Liu
X
X
Butler
B R
BR
Froelich
C J
CJ
Thor
A D
AD
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000473:pathology; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002467:Cell Nucleus / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D004789:Enzyme Activation; D005047:Etoposide / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D014407:Tumor Cells, Cultured
D000903:Antibiotics, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; D005047:Etoposide; D004317:Doxorubicin; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases