RESUMO
BACKGROUND: Interactions between CXCR4 and its ligand CXCL12 have been shown to be involved in cancer progression in colorectal cancer (CRC). We performed a comparative CXCL12/CXCR4 expression analysis and assessed the effect of external CXCL12 stimulation on migration of CRC cells without and with CXCR4 inhibition. METHODS: Expression of CXCL12/CXCR4 was assessed by quantitative real-time PCR, ELISA and immunohistochemistry in resection specimens of 50 CRC patients as well as in the corresponding normal tissues and in three human CRC cell lines with different metastatic potential (Caco-2, SW480 and HT-29). Migration assays were performed after stimulation with CXCL12 and CXCR4 was inhibited by siRNA and neutralizing antibodies. RESULTS: In CRC tissues CXCL12 was significantly down-regulated and CXCR4 was significantly up-regulated compared to the corresponding normal tissues. In cell lines CXCR4 was predominantly expressed in SW480 and less pronounced in HT-29 cells. CXCL12 was only detectable in Caco-2 cells. CXCL12 stimulation had no impact on Caco-2 cells but significantly increased migration of CXCR4 bearing SW480 and HT-29 cells. This effect was significantly abrogated by neutralizing anti-CXCR4 antibody as well as by CXCR4 siRNAs (P < 0.05). CONCLUSIONS: CXCR4 expression was up-regulated in CRC and CXCL12 stimulation increased migration in CXCR4 bearing cell lines. Migration was inhibited by both neutralizing CXCR4 antibodies and CXCR4 siRNAs. Thus, the expression and functionality of CXCR4 might be associated with the metastatic potential of CRC cells and CXCL12/CXCR4 interactions might therefore constitute a promising target for specific treatment interventions.
Assuntos
Movimento Celular , Quimiocina CXCL12/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Inativação Gênica , Receptores CXCR4/genética , Idoso , Anticorpos Bloqueadores/farmacologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quimiocina CXCL12/genética , Neoplasias Colorretais/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Inativação Gênica/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Especificidade de Órgãos/efeitos dos fármacos , Especificidade de Órgãos/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores CXCR4/metabolismoRESUMO
Chemokines have been proposed to contribute to tumour growth and metastatic spread of several cancer entities. Here, we examined the relative levels of CXCL12/CXCR4 in resection specimens from patients with different malignant and non-malignant colorectal diseases as well as colorectal liver metastases (CRLM). CXCL12/CXCR4 mRNA and protein expression profiles were assessed by quantitative real-time PCR, Western blot analysis, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry in resection specimens from patients with ulcerative colitis (UC; n = 15), colorectal adenoma (CRA; n = 15), colorectal adenocarcinoma (CRC; n = 47) and CRLM (n = 16). Corresponding non-affected tissues served as control. In contrast to UC tissues, CXCL12 showed a distinct down-regulation in CRA, CRC and CRLM specimens, whereas the corresponding receptor CXCR4 demonstrated a significant up-regulation in CRC and CRLM related to corresponding non-affected tissues (p < 0.05, respectively). Our results strongly suggest an association between CXCL12/CXCR4 expression and the induction of CRA, CRC and the development of CRLM. Therefore, CXCR4 may be a potential target for specific therapeutic interventions.
Assuntos
Adenocarcinoma/metabolismo , Adenoma/metabolismo , Biomarcadores Tumorais/metabolismo , Quimiocina CXCL12/metabolismo , Neoplasias Colorretais/metabolismo , Neoplasias Hepáticas/metabolismo , Receptores CXCR4/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adenoma/genética , Adenoma/patologia , Adulto , Idoso , Biomarcadores Tumorais/genética , Western Blotting , Quimiocina CXCL12/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Técnicas Imunoenzimáticas , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Prospectivos , RNA Mensageiro/genética , Receptores CXCR4/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de Sobrevida , Adulto JovemRESUMO
As deregulation of miRNAs and chemokine CCL20 was shown to play a role in colorectal cancer (CRC) pathogenesis, we analyzed the functional interactions of candidate miRNAs with CCL20 mRNA. After target prediction software programs indicated a role for miR-21 in CCL20 regulation, we applied the luciferase reporter assay system to demonstrate that miR-21 functionally interacts with the 3'UTR of CCL20 mRNA and down-regulates CCL20 in miR-21 mimic transfected CRC cell lines (Caco-2, SW480 and SW620). Thus, regulation of CCL20 expression by miR-21 might be a regulatory mechanism involved in progression of CRC.