The Effect Of CXCR4 And EGFR On Promoting Metastasis And Invasion Of Ovarian Cancer Cell And Its Application In Cancer Treatment

Stromal cell-derived factor-1(SDF-1), also named SDF-1 is known as the only chemokine until now that could combine and activate the chemokine receptor 4(CXCR 4), a membrane protein as one member of G protein-coupled receptor family. CXCR4 highly expressing on the surface of tumor cell plays a role as a biological phenotype. It functioned in cancer metastasis by the interaction with SDF-1. Epidermal growth factor receptor is one kind of transmembrane glycoprotein which serves as a growth regulation factor in Physiological status. However overexpression of EGFR break cell's normal growth regulation status with a consequence of continuous proliferation and malignant transformation. Recent researches have discovered in tumor cells expressing both EGFR and CXCR4 that a complex network between these two receptors deepens the malignant degree by their"cross-talk"with the accurate mechanism still unknown by now.After screening, we choose ovarian cancer cell SKOV3 which coexpresses CXCR4 and EGFR to investigate the synergistic effect of these two recptors on cancer invasion and metastasis. Our research suggested that:â‘ PI-3k/AKT pathway was activated by EGF causing an increase of CXCR4-positive cells as well as their chemotaxis.â‘¡Affected by EGF and SDF-1,PI-3k/AKT pathway functions in the increase of MMP9, a enzyme closely related to cancer metastasis. Supported by other researches in this field, it is obvious that cancer proliferation, invasion, and metastasis as well as cancer malignant transformation are promoted by the synergistic effect of EGFR and CXCR4. These research results are correspondent with recent clinical reports on CXCR4 and EGFR-positive tumor bearing patients who suffered from high grading tumor, bad prognosis with a disappointing general survival rate. Outcomings indicates that malignant transformation of cancer is a complicated course, which suggests independent inhibition of one certain target is not enough to eliminate cancer, and only if two or more targets are aimed can tumor be thoroughly wiped out.Basing on theory above, we obtain mutant CXCL12 which posses high rivalry activity against CXCR4 by oriented reconstruction on wild CXCL12.Then this new CXCL12 is connected to Decorin mature peptide bridged by antibody heavy chain hinge section, in which way the final Decorin and CXCL12 mutant chimeric protein SDF-1/54-Decorin possessing a dual targeting effect is constructed. This chimeric protein is characterized by the following:It can be concentrated selectively around ovarian cancer, either primartumor or metastasis tissue since it recognizes both EGFR and CXCR4. SDF-1 grad between primartumor and remote specific metastasis organ is interrupted by blocking CXCR4 when it is being binded by rivalry section of mutant SDF-1. Decorin induce specific blockage of EGFR, which further decrease the infiltrative growth and metestate of ovarian cancer.Chimeric gene SDF-1/54-Decorin is inserted into prokaryotic expression vector pET30(+) and successfully expressed as cytorrhyctes in BL21. Active protein with its purity beyond 85% is collected by cytorrhyctes renaturation and purification.In vitro, Molt-4 cell highly expressing CXCR4, A431 cell highly expressing EGFR, SKOV3 highly expressing both are chosen to test the chimeric protein activities in cell which is shown as following:â‘ chimeric protein can induce internalization of EGFR and CXCR4.â‘¡chimeric protein can inhibit cancer cell chemotaxis.â‘¢chimeric protein can inhibit cancer cell proliferation. Results demonstrate the SDF-1/54-Decorin chimeric protein owning duel effect of both CXCR12 and Decorin could exert relative bioactivities targeting both CXCR4 and EGFR, which provides direct and significant trial support for duel target therapy.