OBJECTIVETo compare the durability of quantum dots with that of green fluorescein for labeling survivin antisense oligonucleotide (ASODN) and investigate the difference in growth and apoptosis of cells transfected with the labeled survivin ASODN.

METHODSSurvivin ASODN labeled with quantum dots or green fluorescein was transfected into MCF-7 cells via Lipolifectmain(TM2000). The proliferation of MCF-7 cells was assessed with MTT assay, survivin mRNA expression determined by RT-PCR and its protein expression measured by Western blot analysis. The apoptosis rate of the transfected cells was estimated by flow cytometry, and the fluorescence distribution in the cells observed under fluorescent inverted microscope.

RESULTSThe mRNA and protein expressions of survivin were significantly decreased in the MCF-7 cells after cell transfection with survivin ASODN labeled with quantum dots or green fluorescein, and no significant difference was noted between the two labeling methods (P>0.05). Nor did survivin ASODN transfection with different labeling methods produced significant difference in cell proliferation and apoptotic rate (P>0.05). For green fiuorescein labeling, the fluorescence disappeared 4 days after transfection, whereas the fluorescence sustained for 1 week for quantum dots labeling.

CONCLUSIONSurvivin ASODNs labeled with quantum dots and green fiuorescein do not significantly differ in survivin expression or the transfected cell proliferation and apoptosis rate, but quantum dot labeling can be more stable with longer maintcnance of the labeling.