Cyr61 expression confers resistance to apoptosis in breast cancer MCF-7 cells by a mechanism of NF-kappaB-dependent XIAP up-regulation.
The aggressiveness of a tumor is partly attributed to its resistance to chemotherapeutic agent-induced apoptosis. Cysteine-rich 61 (Cyr61), from the CCN gene family, is a secreted and matrix-associated protein, which is involved in many cellular activities such as growth and differentiation. Here we established a cell model system to examine whether stable expression of Cyr61 in MCF-7 cells can confer resistance to apoptosis and identify possible participating mechanisms. We showed that stable cell lines overexpressing Cyr61 had acquired a remarkable resistance to apoptosis induced by paclitaxel, adriamycin, and beta-lapachone. Most interesting, gel shift and reporter assays showed that the Cyr61-overexpressing cells had significantly increased NF-kappaB activity compared with neo control cells. Blockage of NF-kappaB activity in Cyr61-expressing cells by transfecting with a dominant negative (DN)-IkappaB or with an NF-kappaB decoy rendered them more susceptible to anti-cancer drugs-induced apoptosis. In addition, several NF-kappaB-regulated anti-apoptotic genes were examined, and we found that only XIAP showed a significant 3-4-fold increase in mRNA and protein in Cyr61-overexpressing cells but not in neo control cells. Treatment with inhibitor of apoptosis protein (XIAP)-specific antisense, but not sense, oligonucleotides abolished the apoptosis resistance of the Cyr61-overexpressing cells. At the same time, transfection of these stable cells with DN-IkappaB to block NF-kappaB activity also effectively reduced the elevated XIAP level. Function-neutralizing antibodies to alpha(v)beta(3) and alpha(v)beta(5) could inhibit Cyr61-mediated NF-kappaB activation as well as XIAP expression. Taken together, our data suggested that Cyr61 plays an important role in resistance to chemotherapeutic agent-induced apoptosis in human breast cancer MCF-7 cells by a mechanism involving the activation of the integrins/NF-kappaB/XIAP signaling pathway.
Lin
Ming-Tsan
MT
Department of Surgery, National Taiwan University Hospital, Taipei.
Chang
Cheng-Chi
CC
Chen
Szu-Ta
ST
Chang
Huei-Ling
HL
Su
Jen-Liang
JL
Chau
Yat-Pang
YP
Kuo
Min-Liang
ML
D021581:Active Transport, Cell Nucleus; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002455:Cell Division; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D055515:Cysteine-Rich Protein 61; D004247:DNA / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D005434:Flow Cytometry; D005799:Genes, Dominant; D017930:Genes, Reporter; D006801:Humans; D017874:Immediate-Early Proteins / Q000096:biosynthesis*; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis*; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D016328:NF-kappa B / Q000378:metabolism*; D009285:Naphthoquinones / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D019030:Receptors, Vitronectin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation; D051636:X-Linked Inhibitor of Apoptosis Protein
D000903:Antibiotics, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; C501848:CCN1 protein, human; D055515:Cysteine-Rich Protein 61; D017874:Immediate-Early Proteins; D039302:Integrin alphaVbeta3; D016023:Integrins; D036341:Intercellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009285:Naphthoquinones; D016376:Oligonucleotides, Antisense; D011506:Proteins; D012333:RNA, Messenger; D019030:Receptors, Vitronectin; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; C064660:integrin alphaVbeta5; C014638:beta-lapachone; D004317:Doxorubicin; D004247:DNA; D017239:Paclitaxel