Breast Cancer Research Today is a free monthly online journal that collates and summarizes the latest research about Breast Cancer, including details on symptoms, genetics, screening, treatment, information.

Hypoxia stimulates carcinoma invasion by stabilizing microtubules and promoting the Rab11 trafficking of the alpha6beta4 integrin.

Yoon SO, Shin S, Mercurio AM

Division of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA.

Hypoxia plays a key role in tumor cell survival, invasion, and metastasis. Here we show that hypoxia increases tumor cell invasion by the modulation of Rab11, an important molecule for vesicular trafficking, especially membrane protein recycling and translocation of proteins from trans-Golgi network to plasma membrane. Dominant-negative Rab11 dramatically decreased hypoxia-induced invasion of MDA-MB-231 breast carcinoma cells without affecting cell apoptosis. Hypoxia-induced Rab11 trafficking is regulated by microtubule stability, as evidenced by the findings that hypoxia increases Glu tubulin and that colchicine blocks Rab11 trafficking and invasion. Inhibition of GSK-3beta activity by hypoxia seems to be central to microtubule stabilization and invasion. In fact, expression of a dominant-negative GSK-3beta was sufficient to stimulate invasion in normoxia. One target of Rab11-mediated trafficking that contributes to invasion is the integrin alpha6beta4. Hypoxia induced a significant increase in alpha6beta4 surface expression but it had no effect on the surface expression of alpha3beta1. This increase is dependent on Rab11 and stable microtubules. In summary, we identify vesicle trafficking as a novel target of hypoxic stimulation that is important for tumor invasion.

Published 4 April 2005 in Cancer Res, 65(7): 2761-9.
Full-text of this article is available online (may require subscription).

© 2004-2008 Breast Cancer Research Today. All Rights Reserved.