[Apoptosis antagonizing transcription factor is a gene highly expressed in highly metastatic human osteosarcoma cell...

Osteosarcoma is the most common malignant bone tumor in adolescents and yound adults. It is characterized by a high propensity for pulmonary metastasis. In spite of successful control of the primary tumor, death from pulmonary metastases occurs in > 30% of patients within 5 years. A better understanding of the molecular mechanisms that regulate the process of metastasis can provide a biological foundation for the design of more effective therapy. We established a metastatic model in nude mice with the method of orthotopically transplanting human osteosarcoma cell line SOSP-9607 and selected and isolated SOSP-M with highly metastatic potential. This study is to clone genes associated with osteosarcoma metastasis and to investigate the molecular mechanism of osteosarcoma metastasis by comparing the levels of gene expression between the two cells lines.

Using suppression subtractive hybridization, the substracted cDNA library of highly metastatic human osteosarcoma cell line SOSP-M was constructed. Positive clones were screened by differential screen technique. Partial positive clones were sequenced. The interested upexpressed clones in SOSP-M cells were analyzed through Northern blot and RT-PCR for the low metastatic cell lines SOSP-9607 and OS-9901, highly metastatic cell line SOSP-M and three pulmonic metastatic nodules.

Two positive cDNA clones from highly metastatic cell line SOSP-M subtracted cDNA library were identical(99% homology) to apoptosis antagonizing transcription factor. Northern blot and RT-PCR analysis demonstrated that apoptosis antagonizing transcription factor expressed highly in high metastatic cell line SOSP-M and three pulmonic metastatic nodules, but not in low metastatic cell line SOSP-9607 and OS-9901.

Apoptosis antagonizing transcription factor may play an important role in promoting metastasis of osteosarcoma.