Effection Of Inhibition Of Hypoxia-inducible Factor-1a (HIF-1a) On Chemosensitivity In Human Glioma And Its Mechanisms

Objective: Hypoxia—inducible factor 1 (HIF-1), which is a heterodimeric transcription factor, plays a key role in the hypoxia response and contribute to tumor survival and progression. Multidrug resistance-associated protein (MRP),which belongs to the families of the ATP-binding cassette (ABC) superfamily of transport proteins, is high expressed and involved in the multidrug resistance (MDR) in human gliomas. In vitro study, we knock down the HIF-1 a by RNA interference technique and observe its effection on the chemotherapy sensitivity of T98G. This study is to provide theoretical and experimental data in further investigation aimed on the target of HIF-1 for glioma therapy.Methods:â‘ Transfect the HIF-1 a- siRNA oligos into T98G cells by liposome and expose them to hypoxia (O₂, 1%) environment for 24h,48h and 72h. The negative and mock control groups were established. In order to test the siRNA validation, the expression levels of the HIF-1 a were assessed by the real-time PCR and Western blot analyses .â‘¡Select the valid siRNA and transfect the cells, then incubate in hypoxia (O2 1%) environment for 24h,48h and 72h.The negative and mock control groups were established. The expression levels of the MRP1 were assessed by the real-time PCR and Western blot analyses.â‘¢The cells, which were transfected with HIF-1 a- siRNA, with the mock control groups were established, incubated in 1% O2 for 48 h followed by the assessment of chemosensitivity to cisplatin and doxorubicin by MTT.Results:â‘ The transfection efficiency is approximately to 85%.The gene silencing efficiency is 24h 90%,48h 85%,72h 88% respectively at mRNA level and the protein expression descended 24h 74.5%,48h 61.1%,72h 59.1% correlatly.â‘¡The expression of the MRP1 was inhibited correlating to that of the HIF-1 a. At mRNA level , it descended 24h 24 %,48h 48%,72h 64% respectively and at protein level, it descended 24h 7.6 %,48h 36.8%,72h 45.2% respectively.â‘¢Multidrug resistance to cisplatin and doxorubicin were reversed in HIF-1 a transfected cells.Conclusions: MRP1 expression descended with that of the HIF-1 .Resistance of glioma to chemotherapy could be reversed through inhibition of hypoxia inducible factor-1 a.