Integrin αVβ6-EGFR crosstalk regulates bidirectional force transmission and controls breast cancer invasion

Abstract

The mechanical properties of the extracellular matrix within tumours control multiple cellular functions that drive cancer invasion and metastasis. However, the mechanisms controlling microenvironmental force sensation and transmission, and how these regulate transcriptional reprogramming and invasion, are unclear. Our aim was to understand how mechanical inputs are transmitted bidirectionally and translated into biochemical and transcriptional outputs to drive breast cancer progression. We reveal that adhesion receptor and growth factor receptor crosstalk regulates a bidirectional feedback mechanism co-ordinating force-dependent transcriptional regulation and invasion.Integrin αVβ6 drives invasion in a range of carcinomas and is a potential therapeutic target. αVβ6 exhibits unique biophysical properties that promote force-generation and increase matrix rigidity. We employed an inter-disciplinary approach incorporating proteomics, biophysical techniques and multimodal live-cell imaging to dissect the role of αVβ6-EGFR crosstalk on transmission of mechanical signals bidirectionally between the extracellular matrix and nucleus.We show that αVβ6 expression correlates with poor prognosis in triple-negative breast cancer (TNBC) and drives invasion of TNBC cells. Moreover, our data show that a complex regulatory mechanism exists involving crosstalk between αVβ6 integrin and EGFR that impacts matrix stiffness, force transmission to the nucleus, transcriptional reprogramming and microenvironment rigidity. αVβ6 engagement triggers EGFR & MAPK signalling and αVβ6-EGFR crosstalk regulates mutual receptor trafficking mechanisms. Consequently, EGF stimulation suppresses αVβ6-mediated force-application on the matrix and nuclear shuttling of force-dependent transcriptional co-activators YAP/TAZ. Finally, we show that crosstalk between αVβ6 & EGFR regulates TNBC invasion. We propose a model whereby αVβ6-EGFR crosstalk regulates matrix stiffening, but also the transmission of extracellular forces into the cell in order to co-ordinate transcriptional reprogramming and invasion. To exploit adhesion receptors and receptor tyrosine kinases therapeutically, it will be essential to understand the integration of their signalling functions and how crosstalk mechanisms influence invasion and the response of tumours to molecular therapeutics. Regulation of TP53 Activity through Phosphorylation Regulation of TP53 ActivityRNA Polymerase II Transcription Gene expression (Transcription) Transcriptional Regulation by TP53 Generic Transcription Pathway Costimulation by the CD28 family CD28 dependent PI3K/Akt signaling CD28 co-stimulation VEGFR2 mediated vascular permeability Intracellular signaling by second messengers PIP3 activates AKT signaling Constitutive Signaling by AKT1 E17K in Cancer AKT-mediated inactivation of FOXO1A Regulation of TP53 Activity through Association with Co-factors AKT phosphorylates targets in the nucleus RUNX2 regulates genes involved in cell migration AKT phosphorylates targets in the cytosol Downregulation of ERBB2:...

CSK-mediated signalling by integrins in cancer

“…Fifthly, they can regulate the availability of specific integrin dimers on the surface of the plasma membrane through recycling and endocytosis (Morgan et al, 2013). Sixthly, SFKs can mediate the crosstalk between GFR and integrins (Li et al, 2016;Ichihara et al, 2017;Thomas et al, 2018;Javadi et al, 2020). In the next sections, we will explore some of these mechanisms.…”

“…By coregulating receptor trafficking. For example, EGF causes cointernalization of EGFR/α2β1 in platelets, EGFR/αVβ3 in fibroblasts, and EGFR/αVβ6 in breast cancer cells (Ivaska and Heino, 2011;Thomas et al, 2018). This mechanism allows both families of receptors, integrins and GFRs, to reciprocally co-regulate their surface expression.…”

Circulating tumor cell clusters: Insights into tumour dissemination and metastasis

“…R I P T [21]. Further, several studies documented that integrin-ανβ6 as one of the key player in mesenchymal cells which enhance migration, survival and inactivation of apoptosis of tumour cells [22,23]. Furthermore, during this transition process, proteins such as β-catenin, Smad-2/3, NF-κβ, Snail, Slug and Twist are accumulated within the nuclei and cells acquire higher migration, three-dimensional invasion, scattering capacity, changing the shape as a more elongated pattern and resistance to anoikis [17].…”

Circulating tumour cells: a broad perspective

“…In metastasis, integrin-α νβ 6 binds several ligands from the extracellular matrix, thus maintaining upregulation activity and increasing migration survival and inactivation of apoptosis. Integrin-α νβ 6 is usually overexpressed in breast cancer metastatic lesions during the regulation process, and it plays a key role in tumour growth, invasion, early angiogenesis activity and metastasis [43,44]. Mesenchymal cells then undergo structural changes that enable the invasion of the surrounding extracellular matrix, stroma and platelets.…”