Control of long-distance cell-to-cell communication and autophagosome transfer in squamous cell carcinoma via tunneling nanotubes

Abstract

Tunneling nanotubes (TnTs) are thin channels that temporally connect nearby cells allowing the cell-to-cell trafficking of biomolecules and organelles. The presence or absence of TnTs in human neoplasms and the mechanisms of TnT assembly remains largely unexplored. In this study, we have identified TnTs in tumor cells derived from squamous cell carcinomas (SCC) cultured under bi-dimensional and tri-dimensional conditions and also in human SCC tissues. Our study demonstrates that TnTs are not specific of epithelial or mesenchymal phenotypes and allow the trafficking of endosomal/lysosomal vesicles, mitochondria, and autophagosomes between both types of cells. We have identified focal adhesion kinase (FAK) as a key molecule required for TnT assembly via a mechanism involving the MMP-2 metalloprotease. We have also found that the FAK inhibitor PF-562271, which is currently in clinical development for cancer treatment, impairs TnT formation. Finally, FAK-deficient cells transfer lysosomes/autophagosomes to FAK-proficient cells via TnTs which may represent a novel mechanism to adapt to the stress elicited by impaired FAK signaling. Collectively, our results strongly suggest a link between FAK, MMP-2, and TnT, and unveil new vulnerabilities that can be exploited to efficiently eradicate cancer cells.

Tumor microtubes connect pancreatic cancer cells in an Arp2/3 complex-dependent manner

“…An interesting question relates to the specific composition of the intermediate filaments in TMTs, given the ~70 filament forming intermediate filament proteins found in mammals (Chung et al, 2013). Thus far, CK7 (Veranič et al, 2008;Resnik et al, 2018), CK19 (this study), and vimentin (Ady et al, 2014;Sáenz-de-Santa-María et al, 2017) have been identified in this context. In view of the growing appreciation for the pleiotropic roles of intermediate filament in cancer (Karantza, 2011), their function in TNTs and TMTs assumes greater importance.…”

“…Microtubules could play clear roles in organelle trafficking within TMTs, but also may be important in maintaining the wider diameter of TMTs (Zhang et al, 2019). A number of intermediate filament proteins have been identified in TNTs, including cytokeratins and vimentin (Veranič et al, 2008;Ady et al, 2014;Sáenz-de-Santa-María et al, 2017;Resnik et al, 2018). We find abundant CK19 in TMTs from pancreatic cancer cells both in culture and in a tumor environment.…”

“…TMTs in our DHPC-018 cells also contain microtubules and intermediate filaments. While microtubules are absent from some TNTs (Rustom et al, 2004;Sowinski et al, 2008;Wang et al, 2010;Desir et al, 2018;Kretschmer et al, 2019), they are present in others (Önfelt et al, 2006;Osswald et al, 2015;Jansens et al, 2017;Sáenz-de-Santa-María et al, 2017;Resnik et al, 2018;Zhang et al, 2019). Where examined, the microtubule-containing structures are wider than those lacking microtubules (Önfelt et al, 2006).…”

“…While the initially identified structures were shown to contain actin but not microtubules (Ramírez-Weber and Kornberg, 1999;Rustom et al, 2004;Sowinski et al, 2008;Sartori-Rupp et al, 2019), a number of subsequently identified structures contain microtubules (Önfelt et al, 2006;Gerdes et al, 2013;Osswald et al, 2015;Kumar et al, 2017;Resnik et al, 2018;Kim et al, 2019). Where examined, intermediate filaments have also been identified (Iglič et al, 2007;Ady et al, 2014;Sáenz-de-Santa-María et al, 2017;Resnik et al, 2018). A second difference concerns the size of the structures.…”

The Leader Position of Mesenchymal Cells Expressing N-Cadherin in the Collective Migration of Epithelial Cancer

“…Normal fibroblast-like primary cultures (NF) were derived from the oral mucosa of a non-cancerous young patient. All cell lines were grown as previously described [16] and were periodically tested for human pathogens and mycoplasma infection. To avoid cross-contamination and phenotype changes, the cell lines have not been maintained in long-term cultures.…”