Preliminary study on CXCR4 nuclear localization sequence in metastatic renal cell carcinoma

Abstract

Objective:To investigate the role of SDF-1/CXCR4 in metastasis of renal cell carcinoma and to observe the intracellular location of different CXCR4 segments in renal carcinoma cells.Methods:The potential nuclear localization sequences of different CXCR4 were discovered by nuclear localization software and experiments.Full length and truncated forms of CXCR4 were fused with green fluorescent protein pEGFP-N1 and their influence on subcellular localization was examined by confocal microscopy after transfecting them into renal carcinoma cell line A498.Results:Analysis with PSORT Ⅱ Prediction revealed that the nuclear localization sequence region of CXCR4 was located between amino acids 146 and 149(RPRK).Expression products of the recombinant plasmids with SDF-1 stimulation,including EGFP-CXCR4(1-510 bp),EGFP-CXCR4(1-765 bp) and wild-type EGFP-CXCR4,were mainly located in the cell nuclei.However,expression product of EGFP-CXCR4(1-267 bp) with SDF-1 stimulation was mainly located in the renal cell cytoplasm.Expression product of wild-type EGFP-CXCR4 full length plasmid without SDF-1 stimulation was mainly located in the cell cytoplasm;these results accorded with the results of bioinformatics analysis.Conclusion:Nuclear localization sequence of CXCR4 is located in the amino acids 90 to 170,which provides a theoretical basis for further clarifying the nuclear localization sequences of CXCR4 in renal cell carcinoma cells and for finding new potential target for inhibiting the metastasis of renal cell carcinoma.