Expression And Significance Of Hypoxia Of Inducible Factor-1α In Osteosarcoma

Objective To investigate the expression and the clinical significance of HIF-1a in osteosarcoma; Then to intect the expression of HIF-1a in osteosarcoma cell line SaOS-2, and study the molecular mechanism of HIF-1a activation in hypoxia condition.Methods (1) Immunohistochemical staining(SP) was used to detect the expression of HIF-1 a in 25 osteosarcoma specimens and 10 normal bone tissues. Association of expression of HIF-Ia w ith clinical data was also analyzed. (2) After 8, 12, 24 hours cultured in hypoxia condition of 1% 02, SaOS-2 eel 1 in vitro grew to exponential phase of growth and the model of hypoxia osteosarcoma cell was established successfully. (3) Expression of HIF-1a was detected by the means of RT-PCR and Immunohistochemical staining (SP) in the phase of 8, 12 and 24 hours.Analysed the difference of expression of HIF-1a in normal oxygen and hypoxia condition by statistical means. Results (1)The gene positive rate of HIF-I a in osteosarcoma is 56%, however, the tissue of normal bone was negative in staining. The expression of HI F-1a related significantly to the clinical stage and invasion of soft tissue (P<0. 05), and had no relation to sex, age, tumor size and Dahlin' s classification(P>0. 05). (2) The result of RT-PCR was that expression of HIF-1a mRNA in SaOS-2 cell did not change in hypoxia condition regardless of the phase of hypoxia time, which has been high transcription in normal oxygen . (3) The proteinum expression of HIF-1a was raised in hypoxia condition and positive correlation was existed in the phase of hypoxia time, but no or less expression of HIF-1a was in normal oxygen by the means of SP. They appear linear correlation between the proteinum expression of HIF-1a and time(r=0.944). After 24 hours in hypoxia, positive yellow drop were expressed in cell nucleus and with the phase of time expression of protein of HIF-1a was increased remarkably(p<0.05). Conclusion High expression of HIF-1 a may participated in the progression of osteosarcoma. HIF-1a may be a new indictor for diognosis, gene therapy and prognostic assessment of osteosarcoma. Hypoxia has a little effect in expression of HIF-1a mRNA and can increase the expression of HIF-1a not in transcriptional level but in protein level, which explains molecular mechanism of activation HIF-1a in hypoxia condition and settles the rationale base for thefuture correlated clinical research.