Identification of Metastasis Associated Gene G3BP by Differential Display in Human Cancer Cell Sublines with Different Metastatic Potentials G3BP As Highly Expressed in Non-metastatic

Objective: To investigate genes involved in cancer metastasis, mRNA differential display was used to compare the levels of gene expression in two cell sublines derived from human giant cell carcinoma of lung (PG) which had different metastatic potentials.

Methods: Using in vivo tumorigenicity and a spontaneous metastasis assay in nude mice, two sublines (BE1, LH7) from human giant cell carcinoma of lung (PG) with different metastatic potentials were isolated and characterized. mRNA differential display was used to compare the levels of gene expression between them and the obtained results were confirmed by Northern hybridization.

Results: One differentially expressed band was nearly identical (99% homology) to Ras-GTPase-Activating protein SH3 domain binding protein (G3BP). G3BP displayed a strong expression in LH7 (non-metastatic in recipient nude mice) and a very weak expression in BE1 (100% metastatic frequency). The same different expression level of G3BP was detected in Northern hybridization with another panel of cell sublines with different metastatic potentials (established in our lab) derived from human prostate carcinoma cell line PC-3M.

Conclusion: Our results indicate that G3BP was implicated in cancer metastasis because of its differential expressions in the two panels of cell sublines with different metastatic potentials.