Objective   To analyze the differential expressions of miR-146a

miR-206

miR-223 and let-7c-1

such as cell differentiation-related miRNAs，in CXCR4-positive and CXCR4-negative subsets of the Lewis lung cancer cell lines (LLC).    Methods   CXCR4-positive and CXCR4-negative subsets were isolated from LLC by immunomagnetic beads sorting， and then their total cellular RNA were extracted by Trizol

expression of 4 miRNAs were detected by real-time fluorescence quantitative PCR (TaqMan probe)

and potential target genes of miRNA whose differential expression was the most significant were predicted. Immunohistochemistry was carried out to confirm differential expression of the key molecule of certain research value within CXCR4-positive and CXCR4-negative subsets growing tumor tissue

and a BLAST search was performed to identify homologies of its 3′UTR.    Results   Compared to CXCR4-negative subsets， the expression of 4 miRNAs were lower in CXCR4-positive subsets

and expression of miR-223 had the most significant difference (Fold change=8.6). By softwares forecasting

miR-223 had potential target sites of IGF1R

IGFBP5

Pik3cb， ELK-1 and E2F1 mRNA

such as key molecular of IGF1R signaling pathway. The expression of IGF1R of CXCR4-positive subsets growing tumor tissue was significantly higher than that of CXCR4-negative subsets.    Conclusion   miR-223 is lowly expressed in CXCR4 positive cells from Lewis lung carcinoma cell lines. Position 238～244 nt and 688～695 nt in target sequences of 3′UTR of IGF1R mRNA was highly homologous by screening. Close correlation is found between miR-223 and IGF1R signaling pathway. The mechanisms underlying this biologically important finding need to be further explored.