Effect Of SiRNA Specific For HnRNP B₁ Gene On Telomerase, Cell Cycle And Apoptosis In Lung Adenocarcinoma Cell Line A549

Objective Telomerase is a reverse transcriptase which can keep the lengthof telomere and it is over-expression in lung cancer. Study confirmed that theconjunction of heterogeneous nuclear ribonucleoprotein B₁(hnRNP B₁)andrepeated sequence of telomere can connect the single telomere or telomeraseRNA with the other double strands part. HnRNP B₁ maybe effectmultiplication of lung cancer cell by regulating the activity of telomerase.This study aim to explore the effect of SiRNA specific for hnRNP B₁ gene onexpression of hnRNP B₁ gene, telomerase, cell cycle and apoptosis in lungadenocarcinoma cell line A549.These will provide new experimentalevidence to illustrate the possible relation of hnRNP B₁ and telomerase.Methods 4 line of A549 cells, which were transfected by SiRNA specificfor hnRNP B₁ gene were choosed as experimental group. 1 line of A549 cell, which was transfected by pure plasmid and 1 line of A549 cell were choosed as control group. The expression of target gene hnRNP B₁ mRNA and hTRmRNA were detected by RT-PCR. The activity of telomerase were detectedby TRAP-ELISA. Cell cycle and apoptosis were studied by cell cytometry.Results (1) The expression of hnRNP B₁ mRNA were decreased in theexperimental group. The inhibition ratio were 77.69%, 74.37%, 75.65% and83.04%. (2) The expression of hTR mRNA were decreased in theexperimental group.The inhibition ratio were 79.45%, 65.35%, 60.00% and73.55%. (3) In the experimental group, the activity of telomerase were(0.3017±0.021), (0.4833±0.017), (0.5201±0.012), (0.3305±0.042) while thecontrol group were (1.1597±0.6719) and (1.1556±0.2324). It suggested theactivity of telomerase in the experimental group were significantly decreased.(4) The analysis of cell cycle indicated the cells in the stage G1 increased, the cells in the stage S decreased and they were blockaged in the stage G1 inexperimental group. (5) The rate of apoptosis in the experimental group were(18.26±0.52)%, (21.10±1.54)%, (19.77±3.02)%, (31.13±3.07)% while thecontrol group were(7.3±1.42)% and (9.3±1.45)%. It suggested the rate ofapoptosis in the experimental group were significantly increased. (6) Theexpression of hnRNP B₁ mRNA was significantly positive correlative withthat of hTR mRNA(r=0.986). The expression of hnRNP B₁ mRNA wassignificantly positive correlative with the activity of telomerase(r=0.954), (7)The expression of hTR mRNA was significantly positive correlative with theactivity of telomerase(r=0.971). (8) The activity of telomerase wassignificantly negative correlative with the apoptosis(r=-0.836).Conclusion (1) The SiRNA specific for hnRNP B₁ gene has been shown tointerfere the expression of hnRNP B₁ gene in lung adenocarcinoma cell line A549. (2) The SiRNA specific for hnRNP B₁ gene has been shown tointerfere the expression of hTR and decrease activity of telomerase in lungadenocarcinoma cell line A549. (3) The SiRNA specific for hnRNP B₁ genehas been shown to inhibit cell multiplication and promote apoptosis in lungadenocarcinoma cell line A549. (4) HnRNP B₁ can effect cell multiplicationand apoptosis on lung cancer cell by regulating the activity of telomerase.