Induction of apoptosis in human neuroblastoma cells by abrogation of integrin-mediated cell adhesion.
The survival, proliferation and differentiation of neuroblastoma (NB) cells are largely dependent on adhesion to extracellular matrix (ECM) proteins. Integrin occupancy seems to play a primary role. To elucidate the role of integrin heterodimers during neuronal cell death, we have analysed the changes in integrin expression in 2 human NB cell lines which represent different stages of neuronal maturation. Retinoic acid (RA) had different effects on the 2 NB cell lines: on LAN-5 cells it acted as a differentiation-promoting agent, while it had an anti-proliferative effect on GI-LI-N cells, driving them to apoptosis. Indeed, this occurrence was evidenced by the visualization of a "DNA ladder" on gel electrophoresis, by propidium iodide staining, and by DNA flow cytofluorimetric analysis. RA treatment rapidly and drastically decreased integrin expression and cell adhesion on GI-LI-N cells. These findings were also obtained by treating both NB cell lines with the apoptotic agent fenretinide. Furthermore, treatment of NB cells with anti-sense oligonucleotides to beta 1 integrin chain specifically induced chromatin condensation and nucleosomal DNA laddering. Moreover, blocking cell-matrix interactions by means of perturbing antibody against beta 1 subunit resulted in the induction of typical features of apoptotic cells. In conclusion, these findings indicate that abrogation of cell adhesion through down-modulation of integrin receptors plays a crucial role in the induction of neuroblastoma programmed cell death.
Rozzo
C
C
Molecular Genetics Institute, National Research Council, Alghero, Italy.
Chiesa
V
V
Caridi
G
G
Pagnan
G
G
Ponzoni
M
M
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002448:Cell Adhesion / Q000187:drug effects; D053938:DNA Fragmentation; D004273:DNA, Neoplasm / Q000032:analysis; D015536:Down-Regulation; D017313:Fenretinide / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D019012:Integrin beta1; D016023:Integrins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology*; D016376:Oligonucleotides, Antisense; D016133:Polymerase Chain Reaction; D012334:RNA, Neoplasm / Q000032:analysis; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D019012:Integrin beta1; D016023:Integrins; D016376:Oligonucleotides, Antisense; D012334:RNA, Neoplasm; D017313:Fenretinide; D014212:Tretinoin