OBJECTIVETo investigate the effect of down-regulated proteoglycans on the proliferation of human salivary adenoid cystic carcinoma (SACC).

METHODSThe short hairpin RNA (shRNA) plasmid silencing human xylosyltransferase-I (XT-I) gene was constructed and named shRNA-WJ3. Adenoid cystic carcinoma cells with high metastatic tendency (ACC-M) were transfected by shRNA-WJ3. The plasmid shRNA-HK not targeting any human gene was transfected into ACC-M cells used as negative control. After 48 h of transfection, the positive cells were screened by G418 to isolate the stable transfected cells. Real-time PCR and Western blotting were used to test the gene silence, and the proteoglycans contents of the cells were detected. The stable cell line silenced XT-I was named ACC-M-WJ3. MTT assay was performed to detect the cell proliferation. The cell cycle was analyzed by flow cytometry.

RESULTSShRNA-WJ3 showed powerful RNA interference and gene silence of XT-I. The inhibition rate was 83.70% of mRNA expression and 79.60% of protein expression respectively. The content of proteoglycans in ACC-M-WJ3 was down-regulated by 49.71%-54.59%. The results of MTT assay showed that the cell growth was inhibited significantly. S phrase decreased and G₁-G₀ phrase increased in group ACC-M-WJ3 compared with that of group ACC-M-HK (P < 0.05).

CONCLUSIONSThe down-regulated proteoglycans could inhibit the proliferation of human ACC-M cells.