Different enzyme activities of sialyltransferases in gynecological cancer cell lines.

OBJECTIVE

Due to rarity of a relationship between sialyltransferase enzyme activities and gynecological cancers, we arranged the study to evaluate sialyltransferase enzyme activity in the various kinds of gynecological cancer cell lines.

METHODS

Ten cell lines from various kinds of gynecological cancers and two cell lines from normal tissue were enrolled in this study. The activities of each subtype of sialyltransferases were detected using Gal beta1,3GalNAc-acetyl-lactosamine)-Obz1 (acceptor for ST2,3Gal I), Gal beta1,3GlcNAc beta1,3Gal beta1,4GlcNAc (acceptor for ST2,3Gal III), Gal beta1,4GlcNAc (acceptor for ST2,3Gal IV), asialo-bovine submaxillary mucin (acceptor for ST2,6GalNAc I), asialo-fetuin (acceptor for STalpha2,6GalNAc II), and fetuin (acceptor for ST2,6GalNAc III), respectively. The amounts of sialic acids were measured using fluorescein-conjugated Sambucus nigra agglutinin (SNA) specific for alpha2,6-sialic acids and fluorescein-conjugated Maackia Amurensis agglutinin (MAA) specific for alpha2,3-sialic acids.

RESULTS

The activities of two sialyltransferase subtypes, ST3Gal I & ST6GalNAc II, were significantly higher in nearly all cell lines. More specifically, cervical cancer cell line-ME 180, ovarian cancer cell line-ES-2, and choriocarcinoma cell line-BeWo showed high levels of ST3Gal I enzyme activity; all gynecological cancer cell lines except endometrial cancer cell line-RL95-2 had high levels of ST6GalNAc II enzyme activity when compared with a normal control cell line--fibroblast cell line (CCD-966Sk). Cell lines tested in this study have diverse levels of surface alpha2,6-sialic acid sugar chains (enhanced SNA binding) when compared with alpha2,3-sialic acid sugar chains (enhanced MAA binding) but we found that some cell lines such as Ca Ski (cervical cancer cell line), CC7T (cervical cancer cell line), PA-I (ovarian cancer cell line), and BeWo showed significantly altered cell surface alpha2,6-sialic acid sugar chains.

CONCLUSIONS

Increasing enzyme activity of ST3Gal I and ST6GalNAc II might be important in various kinds of gynecological cancers. More specifically, enhanced activity of sialyltransferases involving alpha2,6-sialic acid sugar chains might be more important in cancer development. Future studies will investigate whether the enzyme activity of these sialyltransferases can be helpful for clinical practice.