[Recombinant human GM-CSF retroviral vector construction and expression in human breast cancer cells].

OBJECTIVE: To provide an effective GM-CSF gene transferring vector mediated by retrovirus and a basis for study of GM-CSF gene-modified tumor cell vaccines. METHODS: The recombinant retroviral vector pDORGM was constructed by cloning the GM-CSF cDNA into the replication defective retroviral vector pDORneo, and transferred into packaging cell line PA317 by Lipofectin method. The viral titer was determined with the NIH3T3. Using the NIH3T3 amplification assay, replication competent retroviral particles were detected. A high titer of retrovirus was used to infect the human breast cancer cell line MCF-7. RESULTS: The retrovirus containing GM-CSF gene had a highest titer of virus of 1 x 10(6) colony-forming units/ml. No replication competent retrovirus were detectable in the vector preparation from the packaging cells. GM-CSF gene-modified MCF-7 cell lines stably released 500 to 800 units/10(6) cell of GM-CSF within 24h in vitro. CONCLUSION: The GM-CSF gene transferring vector mediated by retrovirus was effective and safe. These results provied a basis for study of GM-CSF gene used in cancer gene therapy.