Tetraspanin 8 is a novel regulator of ILK-driven ß1 integrin adhesion and signaling in invasive melanoma cells.
Oncotarget
; 8(10): 17140-17155, 2017 Mar 07.
Article
en En
| MEDLINE
| ID: mdl-28188308
ABSTRACT
Melanoma is well known for its propensity for lethal metastasis and resistance to most current therapies. Tumor progression and drug resistance depend to a large extent on the interplay between tumor cells and the surrounding matrix. We previously identified Tetraspanin 8 (Tspan8) as a critical mediator of melanoma invasion, whose expression is absent in healthy skin. The present study investigated whether Tspan8 may influence cell-matrix anchorage and regulate downstream molecular pathways leading to an aggressive behavior. Using silencing and ectopic expression strategies, we showed that Tspan8-mediated invasion of melanoma cells resulted from defects in cell-matrix anchorage by interacting with ß1 integrins and by interfering with their clustering, without affecting their surface or global expression levels. These effects were associated with impaired phosphorylation of integrin-linked kinase (ILK) and its downstream target Akt-S473, but not FAK. Specific blockade of Akt or ILK activity strongly affected cell-matrix adhesion. Moreover, expression of a dominant-negative form of ILK reduced ß1 integrin clustering and cell-matrix adhesion. Finally, we observed a tumor-promoting effect of Tspan8 in vivo and a mutually exclusive expression pattern between Tspan8 and phosphorylated ILK in melanoma xenografts and human melanocytic lesions. Altogether, the in vitro, in vivo and in situ data highlight a novel regulatory role for Tspan8 in melanoma progression by modulating cell-matrix interactions through ß1 integrin-ILK axis and establish Tspan8 as a negative regulator of ILK activity. These findings emphasize the importance of targeting Tspan8 as a means of switching from low- to firm-adhesive states, mandatory to prevent tumor dissemination.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Transducción de Señal
/
Proteínas Serina-Treonina Quinasas
/
Integrina beta1
/
Tetraspaninas
/
Melanoma
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
/
Male
Idioma:
En
Revista:
Oncotarget
Año:
2017
Tipo del documento:
Article
País de afiliación:
Francia