[Effects of STAT3 antisense oligonucleotide on proliferation and apoptosis of non-small cell lung cancer cell line A549].

BACKGROUND & OBJECTIVE: Signal transducer and activator of transcription 3 (STAT3) is highly expressed in various human tumor tissues and tumor cell lines, and may be involved in tumor genesis and development. This study was to design effective antisense oligonucleotide targeting STAT3 mRNA, and explore its effect on the proliferation and apoptosis of human non-small cell lung cancer cell line A549.

METHODS: Ten sets of antisense sequences targeting STAT3 were designed with RNAstructure4.2 software and STAT3 mRNA total sequences, and transfected respectively into A549 cells (AS group). Cell proliferation inhibition was measured by Cell Count Kit (CCK-8) assay. Cell proliferation and apoptosis were observed under inverted phase contrast microscope. Cell apoptosis was determined by flow cytometry (FCM) with Hoechst33258 staining and Annexin V/PI double staining. The expression of STAT3, p-STAT3, and Bcl-x(L) were detected by Western blot. Cell cycle was detected by FCM.

RESULTS: The 10 sets of designed sequences inhibited the proliferation of A549 cells. The inhibition rate of A549 cell proliferation reached 75.46% after transfection of AS10; the higher the concentration of the antisense oligonucleotide was, the heavier the inhibitory effect was displayed (P<0.01). Apoptotic cells were increased after transfection of antisense oligonucleotide. Antisense oligonucleotide induced early apoptosis in A549 cells: the early apoptosis rate was significantly higher in AS group than in control group (11.51% vs. 5.18%, P<0.01). The expression of STAT3, p-STAT3, and Bcl-x(L) were down-regulated after transfection of antisense oligonucleotide. The G1 phase proportion of A549 cells was significantly higher in AS group than in control group (63.96% vs. 44.47%, P<0.01).

CONCLUSION: The antisense oligonucleotide sequences targeting STAT3 designed with computer could inhibit the proliferation and induce the apoptosis of A549 cells.