Caveolin-1 mutants P132L and Y14F are dominant negative regulators of invasion, migration and aggregation in H1299 lung cancer cells.
Caveolin-1 is an essential protein constituent of caveolae. Accumulating evidence indicates that caveolin-1 may act as a positive regulator of cancer progression. In this study, we investigated the function of caveolin-1 in human lung cancer cells. Caveolin-1 knockdown inhibited cell proliferation and reduced focal adhesion kinase (Fak) phosphorylation. Matrix invasion and cell migration as well as expression and activity of matrix metalloproteases were attenuated following caveolin-1 RNAi-mediated knockdown or overexpression of Y14F and P132L mutants, demonstrating dominant-negative activity of these mutants. Time-lapse fluorescence microscopy revealed that caveolin-1 and its mutants P132L and Y14F are localized to the trailing edge of migrating cells during both random and directed cell movement, implying an active role of caveolin-1 in the migration process. Suppression of caveolin-1 function greatly elevated the percentage of H1299 cells exhibiting focal adhesions. In addition, cell aggregation was increased by wild type caveolin-1 and attenuated by both P132L and Y14F mutants. Overexpression of wild type caveolin-1 increased caveolae density, however, P132L and Y14F mutants did not affect caveolae formation, suggesting that in this respect that the mutants do not act in a dominant negative manner, and that effects of caveolin-1 on caveolae and cell invasion, migration, focal adhesion and aggregation, are separable. Our data provide novel mechanistic insights into the role of caveolin-1 in cell motility, invasiveness and aggregation, therefore, expanding our understanding of the tumor-promoting activities of caveolin-1 in advanced-stage cancer.
Shatz
Maria
M
Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel. shatzm@niehs.nih.gov
Lustig
Gila
G
Reich
Reuven
R
Liscovitch
Mordechai
M
D019943:Amino Acid Substitution; D021941:Caveolae / Q000502:physiology; D051242:Caveolin 1 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology*; D002449:Cell Aggregation / Q000235:genetics / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology; D003285:Contractile Proteins / Q000378:metabolism; D005109:Extracellular Matrix / Q000502:physiology; D064448:Filamins; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D022001:Focal Adhesions / Q000235:genetics / Q000502:physiology; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000503:physiopathology; D045726:Metalloproteases / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D020125:Mutation, Missense; D009361:Neoplasm Invasiveness / Q000235:genetics / Q000503:physiopathology; D010766:Phosphorylation; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection
C495540:CAV1 protein, human; D051242:Caveolin 1; D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D045726:Metalloproteases