| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1993: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
We evaluated the antiproliferative effect of L-myc antisense DNA in NCI-H209, a human small cell lung cancer (SCLC) cell line overexpressing the L-myc gene.The synthetic DNA used in the present study was 15mer oligodeoxynucleoside phosphorothioate (OPT), which showed rapid incorporation into NCI-H209 cells, and which localized mainly in the cell nucleus and weakly in the cytoplasm.The exposure of this cell line to s L-myc antisense DNA convering the translational initiation site L-myc proteins inhibited the cell proliferation in a concentration-dependent manner through the concentrations of 1.6muM to 10muM.Furthermore, the growth inhibition by this antisense DNA was correlated with the level of L-myc expression in three different SCLC cell lines including NCI-H209.A mixed sequence control OPT having the same nucleotide length as the antisense OPT but in random, order, did not show any effect on cell proliferation.The sense OPT treatment induced the some inhibition of cell proliferation, which migh be non-sequence-specific inhibition by OPT independent of conventional antisense gene inhibition, which was reported in other systems.Abundant expression of L-myc mRNA and decreased expression of L-myc protein were observed in the antisense-treated NCI-H209 cells, suggesting that the antisense OPT covering the translational initiation site acted by inhibiting ribosomal translation of the target mRNA,rather than by inhibiting transcription from the gene.
Together with unique characteristics of the L-myc gene, including 1) a frequently amplified and overexpressed state in SCLC,and 2) very restricted and low level expression in human adult tissues, the present data indicate that L-myc is a good candidate for the target gene for antisense DNA therapy in SCLC based on molecular biological diagonosis.
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