engleski

Characterisation of integrin αV-dependent adhesome in tumor cells

Integrins are heterodimeric glycoproteins comprised of α and β subunits that bind cells to extracellular matrix proteins. The connection between integrins and the cytoskeleton is mediated by a dynamic integrin adhesion complex (IAC), which transduces chemical and mechanical signals to control a multitude of cellular functions, including sensitivity to antitumor drugs, migration and invasion. Methods based on proteomics enable the analysis of IAC, the composition of which has been termed adhesome. Our recent focus has been the characterisation of integrin αV-dependent adhesome in three different tumor cell models. The first one is tongue squamous carcinoma Cal27 cell model composed of Cal27 cells and a cell clone obtained by stable transfection of integrin subunit β3 cDNA that led to de novo expression of integrin αVβ3 and increased expression of integrin αVβ5. The β3- transfected cell clone demonstrated decreased sensitivity to cisplatin, mitomycin C, doxorubicin and 5-fluorouracil, and increased cell migration and invasion. The other two cell models were selected based on our recently published data showing that knockdown of integrin αV using specific siRNA sensitizes melanoma cell line MDA- MB-435S and triple negative breast carcinoma cell line MDA-MB-231 to vincristine and paclitaxel. Therefore, the second model involves cell line MDA-MB-435S and corresponding cell clone isolated by stable transfection of integrin αV-specific shRNA expressing plasmid. MDA-MB-435S cells with decreased expression of integrin αV demonstrated increased sensitivity to vincristine and paclitaxel, and decreased migration, which is consistent with transient transfection data. Interestingly, sensitivity pattern of the MDA-MB- 231 cell model was not in line with transient transfection data whereas MDA-MB-231 cell clone with decreased amount of integrin αV demonstrated decreased sensitivity to paclitaxel and vincristine, but still, decreased migration. To precisely understand the role of integrins αV, preferentially αVβ3 and αVβ5, in regulating IAC in tumor cells, we characterised by mass spectrometry (MS), the adhesome of Cal27, MDA-MB-435S and MDA- MB-231 cell lines grown in standard cell culture conditions and compared it to corresponding stable cell clones expressing altered amount of integrin αV. MS data enables the assessment of main integrins used by tumor cells growing as cell culture and the analysis of the composition of IAC recruited by integrins αV. These data represent a valuable resource for improving our understanding of the composition of IAC and adhesion-mediated mechanisms that control sensitivity to antitumor drugs, migration and invasion.

melanoma ; breast cancer ; integrins ; adhesome

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