[Expression changes of tumor metastasis-related genes after overexpression of KAI1 in retinoblastoma Y79 cells].

OBJECTIVE

To investigate the expression changes of tumor metastasis-related genes after overexpression of KAI1 in retinoblastoma Y79 cells.

METHODS

Experimental study. Y79 cells were transfected with a lentivirus vector containing KAI1 and enhanced green fluorescent protein (EGFP) fusion gene, or a control lentivirus vector containing EGFP. Positive transfectants stably expressing high levels of KAI1 were named Y79-KAI1 and control transfectants were named Y79-KAI1/zero. These transfectants were selected by puromycin resistance and analysis with fluorescent microscopy. The expression of KAI1 mRNA and its protein among Y79, Y79-KAI1 and Y79-KAI1/zero were detected by fluorescent quantitative RT-PCR and Western blot. Differential expression of tumor metastasis-related genes in Y79-KAI1 and Y79-KAI1/zero was analyzed with human tumor metastasis PCR array. One-way ANOVA was used to analyze the differences of KAI1 mRNA and protein expression among the three groups.

RESULTS

The stably transfected cell lines of Y79-KAI1 and Y79-KAI1/zero were established. The result of fluorescent quantitative real-time PCR showed that the relative quantification of mRNA level of KAI1 gene in the three kinds of cells above was 183.67 ± 21.20, 1.42 ± 0.55, 1.00 ± 0.00, respectively. And the expression level of KAI1 mRNA in Y79-KAI1 cells was significantly higher than those in Y79-KAI1/zero and Y79 cells (F = 108.74, P = 0.000). The results of Western blot showed that the expression level of the KAI1 protein in Y79-KAI1 cells was significantly higher than those in Y79-KAI1/zero and Y79 cells (F = 34.36, P = 0.001). Immunofluorescent staining showed that Y79 and Y79-KAI1/zero cells had no detectable KAI1 expression, while Y79-KAI1 cells expressed KAI1 in the cytoplasm surrounding the nuclei. Among the 84 tumor metastasis-related genes examined, 7 genes were up-regulated more than 2 folds and 6 genes were down-regulated over 50%.

CONCLUSION

Over-expression of KAI1 may result in differential expression of tumor metastasis-related genes in Y79 cells, which may be related to the inhibitory effect on the tumor metastasis of retinoblastoma.