Apart from their major function in the coordination of leukocyte recruitment, chemokines, in cooperation with their receptors, have been implicated in the progression of various diseases including different types of cancer, affecting survival, proliferation and metastasis. A complex network of chemokines and receptors exists in the tumor microenvironment and affects tumor development in various ways where chemokines activate typical signalling pathways by binding to the respective receptors. The identification and characterization of a group of atypical chemokine receptors [D6, Duffy antigen receptor for chemokines (DARC), ChemoCentryx chemokine receptor (CCX-CKR) and CXCR7] which appear to use unique biochemical properties to regulate the biological activities of these chemokines, is useful in the effort to therapeutically manipulate chemokines in a broad spectrum of diseases in which these chemokines play a critical role. The aim of this review was to investigate the combinatorial effect of two reported atypical chemokine receptors, D6 and DARC, on breast cancer cell invasion to understand their role and therapeutic potential in cancer treatment. In this regard, findings of the present review should be confirmed via the construction of recombinant D6 and DARC clones as well as the expression of the respective recombinant proteins using the Pichia pastoris (P. pastoris) expression system is to be performed in a future study in order to support findings of the current review.
Keywords: Pichia pastoris; breast cancer; chemokine; chemokine decoy receptor protein; chemokine receptor.