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Examining the Role of ARRDC3 in Regulation of PAR1 Trafficking and Signaling in Invasive Breast Carcinoma
Author(s) -
Arakaki Aleena
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.671.8
Subject(s) - cancer research , biology , breast cancer , signal transduction , microbiology and biotechnology , metastasis , cancer , genetics
The G protein‐coupled receptor (GPCR) protease‐activated receptor‐1 (PAR1) is activated by proteases secreted in the extracellular environment. Overexpression of PAR1 in breast cancer correlates with poor patient prognosis and increased breast cancer invasion and metastasis. However, the mechanism(s) by which PAR1 promotes breast cancer invasion and metastasis are not known. Activation of PAR1 occurs through an irreversible proteolytic cleavage event and thus, the precise regulation of receptor signaling is critical for proper cellular responses. The arrestin‐domain containing ARRDC3 protein functions as a tumor suppressor and mediates activated PAR1 lysosomal degradation in HeLa cells. We have previously shown that PAR1 trafficking is dysregulated in invasive breast carcinoma cells, in which ARRDC3 expression is low or absent, resulting in persistent signaling and invasion. We hypothesize that loss of ARRDC3 expression in invasive breast carcinoma results in the dysregulated PAR1 trafficking, persistent signaling and breast cancer invasion we observe. We used a tetracycline‐inducible lentiviral vector to re‐express ARRDC3 in the highly invasive breast carcinoma cell line MDA‐MB‐231. Using biochemical‐ and microscopy‐based approaches, we found that re‐expression of ARRDC3 was sufficient to rescue defective PAR1 trafficking and restored agonist‐induced receptor lysosomal degradation. In addition, activation of PAR1 resulted in a marked increase in Hippo‐YAP signaling in MDA‐MB‐231 cells that was attenuated upon ARRDC3 re‐expression. These findings suggest that ARRDC3 is a critical regulator of PAR1 signaling in invasive breast cancer. We will further investigate whether loss of ARRDC3 affects PAR1‐mediated Hippo‐YAP pathway activity and modulation of breast cancer migration, invasion and tumor growth and metastasis. These studies will be the first to link ARRDC3 to GPCR‐stimulated Hippo‐YAP signaling and will reveal an important pathway for dysregulation of Hippo‐YAP signaling induced by GPCRs in breast cancer. Support or Funding Information Funding for this project was provided by the UCSD Tribal Membership Initiative Graduate Fellowship and UCSD Graduate Training Program in Cellular and Molecular Pharmacology through NIH General Medical Sciences, T32 GM007752 (Aleena Arakaki) and by the National Institute of Health NIGMS R01 GM090689 (JoAnn Trejo).