The Protease Activated Receptor2 Promotes Rab5a Mediated Generation of Pro-metastatic Microvesicles

Abstract

Metastasis, the hallmark of cancer propagation is attributed by the modification of phenotypic/functional behavior of cells to break attachment and migrate to distant body parts. Cancer cell-secreted microvesicles (MVs) contribute immensely in disease propagation. These nano-vesicles, generated from plasma membrane outward budding are taken up by nearby healthy cells thereby inducing phenotypic alterations in those recipient cells. Protease activated receptor 2 (PAR2), activated by trypsin, also contributes to cancer progression by increasing metastasis, angiogenesis etc. Here, we report that PAR2 activation promotes pro-metastatic MVs generation from human breast cancer cell line, MDA-MB-231. Rab5a, located at the plasma membrane plays vital roles in MVs biogenesis. We show that PAR2 stimulation promotes AKT phosphorylation which activates Rab5a by converting inactive Rab5a-GDP to active Rab5a-GTP. Active Rab5a polymerizes actin which critically regulates MVs shedding. Not only MVs generation, has this Rab5a activation also promoted cell migration and invasion. We reveal that Rab5a is over-expressed in human breast tumor specimen and contributes MVs generation in those patients. The involvement of p38 MAPK in MVs-induced cell metastasis has also been highlighted in the present study. Blockade of Rab5a activation can be a potential therapeutic approach to restrict MVs shedding and associated breast cancer metastasis.

Triple-negative breast cancer-derived microvesicles transfer microRNA221 to the recipient cells and thereby promote epithelial-to-mesenchymal transition

“…Based on both in vitro and in vivo observations, we and several other groups have already established that TF and PAR2 are over-expressed in highly aggressive breast cancer cells (10,16,27,28). In our previous investigations (11), we have demonstrated that PAR2 activation by TF-FVIIa or trypsin leads to pro-metastatic MV generation from the human TNBC cell, MDAMB231, which has also been represented here as shown in Fig.…”

“…The exposure of human TNBC cells, MDAMB231 to hypoxia, results in the liberation of MV in a Rab22A-dependent manner, which is capable of promoting focal adhesion formation, invasion, and metastasis to the neighboring recipient cells (27). In the recent past, we have shown that activation of PAR2 by coagulation factors induces prometastatic MV generation from human TNBC cells (10,11).…”

“…EVs are transported via body fluids including urine, blood, synovial fluid, saliva and even are found in interstitial spaces between cells (8,9). Previous studies have revealed that MV from human TNBC cells are capable of inducing migration and invasion to otherwise nonmetastatic BC cells (10,11).…”

“…PAR2-driven AKT/ NF-B activation also promotes human TNBC cell migration and invasion via matrix metalloprotease-2 (MMP-2) induction (19). Previously, we have explored that PAR2 induction not only promotes human TNBC progression but also induces the release of MV with metastatic potential from human TNBC cells (10,11).…”

Protease‐activated receptor 2 promotes actomyosin dependent transforming microvesicles generation from human breast cancer

“…Inhibition of these sequential events results in a fewer MVs count in the cell supernatant suggesting their definite role in PAR2‐mediated MVs generation process. In an earlier report, we have demonstrated that Trypsin‐mediated PAR2 activation results in MVs shedding from MDAMB231 cell surface via Rab5a‐dependent polymerization of actin . Knock‐down of Rab5a or treatment of the cells with its dominant‐negative (DN) form impairs both Trypsin‐induced actin polymerization as well as subsequent MVs generation.…”