OBJECTIVETo study the effect of the inhibition of CD44 gene expression on the growth of human nasopharyngeal carcinoma cell CNE-2L2 in vitro.

METHODSCD44 gene expression in cells was suppressed by siRNA which was introduced into cells through retrovirus infection. Integration of siRNA into genomic DNA was examined by genomic PCR. CD44 gene expression in cells was detected by Western blot analysis. Cell growth in vitro was assayed using Cell Titer 96 AQueous One Solution Cell Proliferation Assay kit Promega. Cells were stained with propidium iodium and cell DNA content was detected upon a flow cytometer.

RESULTSsiRNA was integrated into genomic DNA of host cells. The 4 cell pools integrated with one of the 4 siCD44s showed a significant inhibition of CD44 gene expression comparing to the controls, the wild type cell and the cell pool integrated with siegfp. The cell pools integrated with siCD44-1 or siCD44-2 showed the most profound inhibition. Growth of these 2 cells in vitro was compared to that of the controls and was found to be significantly inhibited. Cell DNA content analysis indicated 44.4%, 45.5%, 53.9%, and 53.3% in G0/G1 phase; 39.3%, 40.0%, 27.1%, and 28.2% in S phase; and 16.3%, 14.5%, 19.0%, and 18.5% in G2/M phase for the wild type cell, the cell pool integrated with siegfp, the cell pools integrated with siCD44-1, and the cell pools integrated with siCD44-2, respectively.

CONCLUSIONReduction in CD44 expression inhibit the growth of CNE-2L2 cell and affects the development of cells from G0/G1 into S phase, but may somehow promote cells to develop from S into G2/M phase.