Login to Access Video or Poster Abstract: MP99-11
Sources of Funding: This work was supported by grants from National Science Foundation of China (NSFC 81172439 and 81402110), NIH RO1CA174798, prostate cancer SPORE P50 CA140388, Cancer Prevention and Research Institute of Texas (CPRIT RP110327, RP150179), the Prostate Cancer Foundation, and cancer center core grant CA16672.

Introduction

Angiomotin (AMOT) is a family of proteins found to be a component of the apical junctional complex of vertebrate epithelial cells and is recently found to play important roles in neurofibromatosis type 2 (NF-2). Whether AMOT plays a role in prostate cancer (PCa) is unknown.

Methods

Purified GST-AMOTp80 was used as immunogen for antibody generation. Real-time PCR, western blot and immunohistochemistry were used to identify the expression of AMOT. To study the function of AMOT, retroviral vector were constructed, also shRNA was used to knockdown AMOT in cells. Cell migration and invasion assays were performed by using transwell chambers. Nuclear and cytoplasmic protein fractions were prepared by using NE-PER reagents (Pierce). The SPSS 19.0 software was used for statistical analysis. Chi-square test and t test were used for the comparisons between groups.

Results

AMOT is expressed as two isoforms, AMOTp80 and AMOTp130, which has a 409 aa N-terminal domain that is absent in AMOTp80. Both AMOTp80 and AMOTp130 are expressed in LNCaP and C4-2B4, but at a low to undetectable level in PC3 cells. Further study showed that AMOTp130 and AMOTp80 have distinct functions in PCa cells. We found that AMOTp80 functioned as a tumor promoter by enhancing PCa cell proliferation while AMOTp130 did not. Mechanistic studies showed that AMOTp80 signaled through the Hippo pathway by promoting the nuclear translocation of YAP, resulting in an increased expression of YAP target protein BMP4. Moreover, inhibition of BMP receptor activity by LDN-193189 abrogates AMOTp80-mediated cell proliferation.

Conclusions

Together, this study reveals a novel mechanism whereby the AMOTp80-Merlin-MST1-LATS-YAP-BMP4 pathway leads to AMOTp80-induced tumor cell proliferation.

Funding

This work was supported by grants from National Science Foundation of China (NSFC 81172439 and 81402110), NIH RO1CA174798, prostate cancer SPORE P50 CA140388, Cancer Prevention and Research Institute of Texas (CPRIT RP110327, RP150179), the Prostate Cancer Foundation, and cancer center core grant CA16672.