Objective: To establish a bioluminescent MDA-MB-231 cell line which can stably express luciferase and green fluorescent protein to allow bioluminescent imaging in nude mouse models bearing human triple-negative breast cancer xenografts.
Methods: The lentivirus carrying luc2, eGFP and neo fusion genes were packaged in 293T cells via calcium phosphate co-precipitation. Human triple-negative breast cancer cell line MDA-MB-231 was infected by the lentivirus, and the positive cell clones were tested for eGFP and luc2 expressions by fluorescence microscopy and Xenogen IVIS200 bioluminescent imaging system, respectively. MTT assay, transwell invasion assay and wound healing assay were performed to evaluate the changes in the proliferation, invasion and migration abilities of the infected cells. The cells were then orthotopically implanted into the right second mammary fat pat of female BALB/c nude mice. The tumor growth was monitored by the in vivo imaging system every week, and the tumor tissues were harvested to evaluate the in vivo stability and tumorigenicity of the modified cells using cryosection and HE staining.
Results: The lentivirus-infected MDA-MB-231cells could stably express luc2 and eGFP, and the luciferase activity reached 9689 phontons/s/per cell. No significant changes occurred in the biological activities of the lentivirus-infected MDA-MB-231 cells. We successfully established the nude mouse model bearing orthotopically implanted human triple-negative breast cancer cells.
Conclusion: The modified MDA-MB-231 cell line can be detected sensitively at the primary implantation site and distant metastasis site in nude mice, which provides a convenient and sensitive platform for the research of metastatic mechanism and new antitumor drugs of human triple-negative breast cancer. The combination of eGFP and luc2 is superior to single reporter gene.