Abstract
Beclin 1 is a haplo-insufficient tumor suppressor that is decreased in many human tumors. The function of Beclin 1 in cancer has been attributed primarily to its role in the degradative process of macroautophagy. However, Beclin 1 is a core component of the Vps34/Class III PI3K (PI3KC3) and Vps15/p150 complex that regulates multiple membrane trafficking events. In the current study, we describe an alternative mechanism of action for Beclin 1 in breast cancer involving its control of growth factor receptor signaling. We identify a specific stage of early endosome maturation that is regulated by Beclin 1, the transition of APPL1-containing phosphatidyIinositol 3-phosphate-negative (PI3P-) endosomes to PI3P+ endosomes. Beclin 1 regulates PI3P production in response to growth factor stimulation to control the residency time of growth factor receptors in the PI3P-/APPL+ signaling competent compartment. As a result, suppression of BECN1 sustains growth factor stimulated AKT and ERK activation resulting in increased breast carcinoma cell invasion. In human breast tumors, Beclin 1 expression is inversely correlated with AKT and ERK phosphorylation. Our data identify a novel role for Beclin 1 in regulating growth factor signaling and reveal a mechanism by which loss of Beclin 1 expression would enhance breast cancer progression.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
