To construct THY1 gene eukaryotic expression plasmid and study its effects on epithelial ovarian cancer SKOV3 cell lines.

The gene fragment code for THY1 was obtained from human normal ovarian tissues using RT-PCR, and inserted into the eukaryotic expression plasmid pcDNA3.1(+ ) to construct the recombinant plasmid pcDNA3.1(+ )-THY1, which was transfected into SKOV3 cells from March 2005 to March 2007. Experimental cells were classified into 3 groups: SKOV3-THY1 group, SKOV3-Null group and SKOV3 group. The expression of THY1 mRNA and its protein were examined by RT-PCR and Western blot. The cell proliferation and cell cycles were evaluated by methyl thiazolyl tetrazolium (MTT)assay and flow cytometry. Tumor sizes were measured in vivo tumorigenicity studies.

The gene fragment of THY1 was correctly inserted into the eukaryotic expression plasmid pcDNA3.1(+ ) as verified by PCR, restriction endonucleases digestion and DNA sequencing, and the pcDNA3.1(+ )-THY1 has been transfected into SKOV3 cells and obtained stable expression by RT-PCR and Western blot methods. The cell inhibitory rate of the SKOV3-THY1 group(56.6% at the 5th day) was higher than the SKOV3-Null group(12.5%), there was significant difference between them(P<0.05). After transfected by vector pcDNA3.1(+ )-THY1, the ratio of G₁ phase of SKOV3 cells was increased and the ratio of S phase was decreased significantly. There were significant difference between SKOV3-THY1 group and SKOV3-Null group or SKOV3 group(P<0.05), but there were no significant difference between SKOV3-Null group and SKOV3 group(P>0.05). In vivo tumorigenicity studies, tumors grew quite rapidly in the null transfectants compared with the THY1-transfected cells over the next 4 weeks.

THY1 transfection can inhibit the growth of epithelial ovarian cancer SKOV3 cells in vitro and in vivo. THY1 gene may play an important role in generation and development of ovarian cancers.