OBJECTIVETo explore the relationship of CD44 expression or glycosylation and hepatocellular carcinoma (HCC) metastasis.

METHODSIHC, Quantum dots detection, RT-PCR, Western blot, Cellular immune fluorescence and MS-PCR were used to identify CD44 expression in HCC samples and a series of human HCC cell lines with different metastatic potentials. Lectin array was used to reveal the relationship of CD44v6 glycosylation and human HCC metastasis.

RESULTSImmunohistochemistry analysis showed that CD44v6 was mainly distributed on the cell membrane, while CD44S immunoreactivity was prominently in the cytoplasm, CD44v3 and CD44v4/5 were in cytoplasm on membrane. Among CD44S and those CD44 variants, only the expression of CD44v6 was higher in metastasis HCC samples as compared to that in non-metastasis group (x²=8.828, P less than 0.05). This result was also re-confirmed by the result of Quantum dots (t = 2.392, P < 0.05) and serum detection (t = 2.56, P < 0.05). We found completely methylation of CD44v6 gene in Hep3B and incomplete methylation in MHCC97H and MHCC97L cell lines with metastatic potentials. The lectin affinity assay indicated that lectin MAL, SNA and WGA showed more affinity to MHCC97H and MHCC97Lcell lines than that of the non-metastatic Hep3B cell lines.

CONCLUSIONSCD44v6 over-expression presents a positive correlation with HCC metastatic potential, which may be associated with DNA methylation level in promoter sequence. The increasing sialic acid modified glycan of CD44v6 might be related to HCC metastatic ability.