title: CXCR4/CXCL12 axis promotes VEGF-mediated tumor angiogenesis through Akt signaling pathway.
abstract: CXC chemokine receptor 4 (CXCR4) has been shown to play a critical role in chemotaxis and homing, which are key steps in cancer metastasis. There is also increasing evidence that links this receptor to angiogenesis; however, its molecular basis remains elusive. Vascular endothelial growth factor (VEGF), one of the major angiogenic factors, promotes the formation of leaky tumor vasculatures that are the hallmarks of tumor progression. Here, we investigated whether CXCR4 induces the expression of VEGF through the PI3K/Akt pathway. Our results showed that CXCR4/CXCL12 induced Akt phosphorylation, which resulted in upregulation of VEGF at both the mRNA and protein levels. Conversely, blocking the activation of Akt signaling led to a decrease in VEGF protein levels; blocking CXCR4/CXCL12 interaction with a CXCR4 antagonist suppressed tumor angiogenesis and growth in vivo. Furthermore, VEGF mRNA levels correlated well with CXCR4 mRNA levels in patient tumor samples. In summary, our study demonstrates that the CXCR4/CXCL12 signaling axis can induce angiogenesis and progression of tumors by increasing expression of VEGF through the activation of PI3K/Akt pathway. Our findings suggest that targeting CXCR4 could provide a potential new anti-angiogenic therapy to suppress the formation of both primary and metastatic tumors.
authors.affiliation: Department of Hematology/Oncology, Winship Cancer Institute, 1365C Clifton Road, N.E., Clinic C5008, Atlanta, GA 30322, USA.
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Liang
authors.forename: Joann
authors.initials: J
authors.lastname: Brooks
authors.forename: Margaret
authors.initials: M
authors.lastname: Willard
authors.forename: Ke
authors.initials: K
authors.lastname: Liang
authors.forename: Younghyoun
authors.initials: Y
authors.lastname: Yoon
authors.forename: Seunghee
authors.initials: S
authors.lastname: Kang
authors.forename: Hyunsuk
authors.initials: H
authors.lastname: Shim
mesh_terms: D001943:Breast Neoplasms / Q000098:blood supply* / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation; D002478:Cells, Cultured; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D010455:Peptides; D012333:RNA, Messenger; D019718:Receptors, CXCR4; C488289:TN14003; D042461:Vascular Endothelial Growth Factor A; D051057:Proto-Oncogene Proteins c-akt