Prognostic significance of apoptosis regulators in breast cancer.
Dysregulation of normal programmed cell death mechanisms plays an important role in the pathogenesis and progression of breast cancer, as well as in responses of tumors to therapeutic intervention. Overexpression of anti-apoptotic members of the Bcl-2 family such as Bcl-2 and Bcl-X(L) has been implicated in cancer chemoresistance, whereas high levels of pro-apoptotic proteins such as Bax promote apoptosis and sensitize tumor cells to various anticancer therapies. Though the mechanisms by which Bcl-2 family proteins regulate apoptosis are diverse, ultimately they govern decision steps that determine whether certain caspase family cell death proteases remain quiescent or become active. To date, approximately 17 cellular homologs of Bcl-2 and at least 15 caspases have been identified in mammals. Other types of proteins may also modulate apoptotic responses through effects on apoptosis-regulatory proteins, such as BAG-1-a heat shock protein 70 kDa (Hsp70/Hsc70)-binding protein that can modulate stress responses and alter the functions of a variety of proteins involved in cell death and division. In this report, we summarize our attempts thus far to explore the expression of several Bcl-2 family proteins, caspase-3, and BAG-1 in primary breast cancer specimens and breast cancer cell lines. Moreover, we describe some of our preliminary observations concerning the prognostic significance of these apoptosis regulatory proteins in breast cancer patients, contrasting results derived from women with localized disease (with or without node involvement) and metastatic cancer.
Krajewski
S
S
The Burnham Institute, Program on Apoptosis and Cell Death Research, La Jolla, California 92037, USA.
Krajewska
M
M
Turner
B C
BC
Pratt
C
C
Howard
B
B
Zapata
J M
JM
Frenkel
V
V
Robertson
S
S
Ionov
Y
Y
Yamamoto
H
H
Perucho
M
M
Takayama
S
S
Reed
J C
JC
D000970:Antineoplastic Agents / Q000627:therapeutic use; D017209:Apoptosis; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D020169:Caspases / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D019254:Genes, bcl-2; D006801:Humans; D008875:Middle Aged; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D011247:Pregnancy; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
D000970:Antineoplastic Agents; C494826:BAX protein, human; C091732:BCL2-associated athanogene 1 protein; C494811:BCL2L1 protein, human; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D014157:Transcription Factors; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D020169:Caspases