title: Knockdown of chemokine receptor CXCR4 gene by RNA interference: Effects on the B16-F10 melanoma growth.
abstract: The incidence of malignant melanoma has increased greatly in recent decades presenting a high mortality rate despite intensive efforts in this area of research. Recent studies indicate that the chemokine receptor 4 (CXCR4) plays a critical role in cancer. Thus, it has been reported that CXCL12 binding to CXCR4 initiates various downstream signaling pathways that result in a plethora of responses involved in cell proliferation and metastasis. Recently, we demonstrated that CXCR4 silencing by RNA interference (RNAi) significantly reduced the number of pulmonary metastatic nodules. In the present study, we examined the effect of the intratumoral injection of CXCR4 short hairpin (shRNA) expressing plasmids on the growth of B16‑F10 melanoma in mice. In vitro transfection of these tumor cells with CXCR4 shRNA expressing plasmid (CXCR4 shRNA) significantly reduced the levels of CXCR4 mRNA (85%) and CXCR4 protein (70%) compared with the control. We showed that the tumor growth was significantly reduced (66%) in mice inoculated with transfected B16‑F10 melanoma cells when compared with the control group. We also found that the intratumoral injection of CXCR4 shRNA expressing plasmids results in a significant inhibition (70%) of B16‑F10 melanoma growth. This finding supports the hypothesis that a direct administration of RNAi‑based therapeutics into the target tumor is a promising approach for overcoming the hurdles of systemic delivery. The present study is the first demonstration that CXCR4 plays a critical role in B16-F10 melanoma growth. Currently there is great interest in the development of antagonists for therapeutic targeting CXCR4 expression. Considering our results and the fact that CXCR4 is highly conserved between human and mouse, this experimental model of cancer may be useful for the discovery of new CXCR4 antagonists with clinical implications.
authors.affiliation: Federal University of Sao Joao del‑Rei, 35501296 Divinópolis, MG, Brazil.
authors.forename: Nayara Delgado
authors.initials: ND
authors.lastname: André
authors.affiliation: Molecular Oncology Research Center, Barretos Cancer Hospital, 14784-400 Barretos, SP, Brazil.
authors.forename: Viviane Aline Oliveira
authors.initials: VA
authors.lastname: Silva
authors.affiliation: Department of Pathological Sciences, Biological Sciences Center, State University of Londrina, 86057‑970 Londrina, PR, Brazil.
authors.forename: Maria Angelica Ehara
authors.initials: MA
authors.lastname: Watanabe
authors.affiliation: Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of São Paulo, 14049‑900 Ribeirao Preto, SP, Brazil.
authors.forename: Fernando Luiz
authors.initials: FL
authors.lastname: De Lucca
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D054377:Chemokine CXCL12 / Q000378:metabolism; D055785:Gene Knockdown Techniques / Q000379:methods; D008546:Melanoma, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D051379:Mice; D058990:Molecular Targeted Therapy; D010957:Plasmids / Q000235:genetics; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000494:pharmacology; D019718:Receptors, CXCR4 / Q000235:genetics* / Q000378:metabolism*
chemical_list: C514936:CXCR4 protein, mouse; D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D034741:RNA, Small Interfering; D019718:Receptors, CXCR4