Caveolin-1 expression sensitizes fibroblastic and epithelial cells to apoptotic stimulation.
The potential role of caveolin-1 in apoptosis remains controversial. Here, we investigate whether caveolin-1 expression is proapoptotic or antiapoptotic using a well-defined antisense approach. We show that NIH/3T3 cells harboring antisense caveolin-1 are resistant to staurosporine-induced apoptosis, as assessed using cell morphology, DNA content, caspase 3 activation, and focal adhesion kinase cleavage. Importantly, sensitivity to apoptosis is recovered when caveolin-1 levels are restored. Conversely, recombinant stable expression of caveolin-1 in T24 bladder carcinoma cells sensitizes these cells to caspase 3 activation. Consistent with the observations using NIH/3T3 cells, downregulation of caveolin-1 in T24 cells substantially diminishes caspase 3-like activity. Loss of sensitivity to apoptotic stimulation is recovered by inhibition of the phosphatidylinositol 3-kinase pathway using LY-294002, suggesting a possible mechanism for the sensitizing effect of caveolin-1. Thus our results suggest that caveolin-1 may act as a coupling or sensitizing factor in signaling apoptotic cell death in both fibroblastic (NIH/3T3) and epithelial (T24) cells.
Liu
J
J
Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA.
Lee
P
P
Galbiati
F
F
Kitsis
R N
RN
Lisanti
M P
MP
D016475:3T3 Cells; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D051242:Caveolin 1; D022461:Caveolins / Q000235:genetics*; D002867:Chromones / Q000494:pharmacology; D016373:DNA, Antisense; D015536:Down-Regulation / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology* / Q000201:enzymology; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000201:enzymology; D001749:Urinary Bladder Neoplasms
C495540:CAV1 protein, human; C495541:Cav1 protein, mouse; D051242:Caveolin 1; D022461:Caveolins; D002867:Chromones; D016373:DNA, Antisense; D004791:Enzyme Inhibitors; D009025:Morpholines; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D019311:Staurosporine