Scientists at the MedUni Vienna, in collaboration with a working group led by Nancy Hynes at the University of Basel, have discovered a new approach in the treatment of breast cancer: an international team involving the Clinical Institute of Pathology at the MedUni Vienna has been able to demonstrate the activation of a receptor, the Ret protein (Rearranged during transfection), on the surface of breast cancer cells. Increased levels of this protein are associated with a lower likelihood of survival for breast cancer patients.
We show that elevated levels of Ret receptor are found in different sub-types of human breast cancers and that high Ret correlates with decreased metastasis-free survival. The role of Ret in ER+ breast cancer models was explored combining in vitro and in vivo approaches. Our analyses revealed that ligand-induced Ret activation: (i) stimulates migration of breast cancer cells; (ii) rescues cells from anti-proliferative effects of endocrine treatment and (iii) stimulates expression of cytokines in the presence of endocrine agents. Indeed, we uncovered a positive feed-forward loop between the inflammatory cytokine IL6 and Ret that links them at the expression and the functional level. In vivo inhibition of Ret in a metastatic breast cancer model inhibits tumour outgrowth and metastatic potential. Ret inhibition blocks the feed-forward loop by down-regulating Ret levels, as well as decreasing activity of Fak, an integrator of IL6-Ret signalling. Our results suggest that Ret kinase should be considered as a novel therapeutic target in subsets of breast cancer.
- Read New Approach in the Treatment of Breast Cancer,ScienceDaily, 8 Aug, 2013.
- Sources Ret inhibition decreases growth and metastatic potential of estrogen receptor positive breast cancer cells – Full PDF, EMBO.