Inhibiting FAK–Paxillin Interaction Reduces Migration and Invadopodia-Mediated Matrix Degradation in Metastatic Melanoma Cells

Abstract

The nonreceptor tyrosine kinase FAK is a promising target for solid tumor treatment because it promotes invasion, tumor progression, and drug resistance when overexpressed. Investigating the role of FAK in human melanoma cells, we found that both in situ and metastatic melanoma cells strongly express FAK, where it controls tumor cells’ invasiveness by regulating focal adhesion-mediated cell motility. Inhibiting FAK in human metastatic melanoma cells with either siRNA or a small inhibitor targeting the kinase domain impaired migration but led to increased invadopodia formation and extracellular matrix degradation. Using FAK mutated at Y397, we found that this unexpected increase in invadopodia activity is due to the lack of phosphorylation at this residue. To preserve FAK–Src interaction while inhibiting pro-migratory functions of FAK, we found that altering FAK–paxillin interaction, with either FAK mutation in the focal adhesion targeting (FAT) domain or a competitive inhibitor peptide mimicking paxillin LD domains drastically reduces cell migration and matrix degradation by preserving FAK activity in the cytoplasm. In conclusion, our data show that targeting FAK–paxillin interactions could be a potential therapeutic strategy to prevent metastasis formation, and molecules targeting this interface could be alternative to inhibitors of FAK kinase activity which display unexpected effects.

Terminalia catappa leaf extracts inhibited metastasis of A2058 and A375 melanoma cells via downregulating p-Src and β-catenin pathway in vitro

“…The expression of p-FAK (Tyr397) and p-Src (Tyr416) protein was suppressed in Western blot ( Figure 6 ). Previous studies showed that melanoma cells might be hindered in accelerating invadopodia activity, and subsequently, Vimentin was suppressed ( Liu and Feng, 2010 ; Nagathihalli and Merchant, 2012 ; Mousson et al, 2021 ). Involvement in regulating melanocyte proliferation, β-catenin is most likely associated with the activation of MITF expression ( Larue and Delmas, 2006 ).…”

“…Previous studies have found that tyrosine phosphorylation regulates focal contact assembly and can occur rapidly ( Parsons, 2003 ). Using the FAK mutation at Tyr397, a binding site for Src, the study verified that while downregulating cell migration, this mutation releases a pool of active Src that modulates enhanced invadopodia activity ( Mousson et al, 2021 ). Inhibition of the FAK/Src interaction enhances the proteolytic activity of invasive melanoma cells ( Mousson et al, 2021 ).…”

“…Using the FAK mutation at Tyr397, a binding site for Src, the study verified that while downregulating cell migration, this mutation releases a pool of active Src that modulates enhanced invadopodia activity ( Mousson et al, 2021 ). Inhibition of the FAK/Src interaction enhances the proteolytic activity of invasive melanoma cells ( Mousson et al, 2021 ). Importantly, Src plays a control role in the expression of E-cadherin ( Serrels et al, 2011 ).…”

The role of RHAMM in cancer: Exposing novel therapeutic vulnerabilities

“…Relevant to RHAMM is that ERK1/2 regulates the association between FAK and paxillin, a focal adhesion (FA) adaptor protein, by ensuring a phosphorylation/dephosphorylation feedback loop that influences FA assembly and disassembly during cell migration ( 46 , 106 , 107 ). Activation of the ERK1/2 pathway by HA : RHAMM interaction increased tyrosine phosphorylation of FAK with a resultant increase in FA turnover and consequently cell migration ( 46 , 47 ).…”

The role of dual‐specificity phosphatase 3 in melanocytic oncogenesis

“…Gain of function of paxillin has been linked with a variety of malignancies, 98 including melanoma, as it participates in adhesion and migration of the malignant cells. 99 There is indication that DUSP3 suppresses paxillin's activity through direct dephosphorylation or impairment of the FAK-paxillin interaction via the pathways mentioned above. 96 Nevertheless, additional studies are necessary for clarifying the exact relationship between FAK and paxillin.…”