| Part1 Expression of HIF-1?/BCL-2 in SACC and its Relationship with Clinicopathologic featuresObjective: Hypoxia inducible factor-1?(HIF-1?)protein plays crucial roles in the prognosis of patients with many malignance tumors and the responsiveness of treatment.The aim of this study was to inwestigate the expression of HIF-1? and B-cell lymphoma(BCL-2)in salivary adenoid cystic carcinoma(SACC).Methods: Fifty-six sections from primary resection of SACCs were obtained from the First Affiliated Hospital of Anhui Medical University to detect HIF-1? by immunohistochemical staining.Semiquantitatively immunoreactive score(IRS)was further calculated to evaluate the degree of HIF-1? and BCL-2 expression in SACC.Results: Using IRS,in which s score of 3 or more indicates HIF-1? expression,36samples(64.3%)were found to expression HIF-1?.The level of HIF-1? was sifnificantly correlated with TNM stage of tomors(P=0.03).Simultaneously,there was a statistical association between HIF-1? level and the primary site of SACC(P=0.004).Positive BCL-2 expression was detected in 55 cases(98.2%),forty-four of which showed strong expression(78.6%).According to results of statistical analysis,IRS of HIF-1? was positively correlated with that of BCL-2(?=0.236,P=0.013)and the significant correlation between HIF-1? and TNM stage was dependent upon the strong expression of BCL-2(Z=2.43,P=0.015).Conclusion:It is helpful to evaluate the prognosis and treatment of patients with SACC by detection of HIF-1? protein.Part2 Influence of HIF-1? on the Radiosensitivity of SACC cellsObjective: Salivary adenoid cystic carcinoma(SACC)is a salivary gland malignant tumor of epithelial origin.The effective treatment should be deeply studied for the blockage of recurrence and metastasis in the patients with SACC.The previous clinical studies had demenstrated that SACC cells exhibited radioresistance.Hypoxia inducible factor-1,as a heterodimeric protein,is a transcription factor in human solid malignant neopasms and composed of ? and ? subunit.Usually,the expression of HIF-1? is stable and the expression of HIF-1? is strictly regulated by oxygen concentration.The growth of tumor can be limited by inhibiting the expression of HIF-1?,and the radioresistence of tumor will be raised by upregulating the expression of HIF-1?.B-cell lymphoma-2(BCL-2),as one anti-apoptotic gene,is an impotant target protein of the radiosensitivity of tumor cells.HIF-1? has one significant correlation with BCL-2 in the malignant tumor of kidney in previous study and is related to the prognosis.In the present study,SACC cells with high expression of HIF-1? were established to observe HIF-1?/BCL-2 signaling and the change of radiosensitivity of tumor cells with high expression of HIF-1? in SACC.Methods: ACC-2 cells,one SACC cell line,were transfacted by two recombinant plasmids with high expression of HIF-1?,mutant-type plasmid with high expression under normoxia and wild-type one with high expression under hypoxia.Meanwhile,parental ACC-2 cells and the cells with free vectors were used as control.ACC-2/MHIF-1?,ACC-2/W-HIF-1? and ACC-2/F were obtained by G418 selecting.The levels of protein and m RNA in cells were tested by RT-PCR and Western Blot respectively.The growth capacities of four cells were observed by cell proliferation assay after exposed to different dose of X-ray under different conditions.The survival fractions(SF)of four cells were observed and calculated by clonogenic asaay exposed to different dose(0,2,3 5Gy)of irradiation under normoxia.Results: Two SACC cells with high HIF-1? expression were transfacted and selected successfully.The levels of HIF-1? m RNA were significantly increased in ACC-2/MHIF-1? and ACC-2/W-HIF-1? cells(P<0.05).Furthermore,the levels of HIF-1? and BCL-2 proteins expression can be up-regulated by Co Cl2 treatment.Conversely,the the expression of HIF-1? and BCL-2 was reduced by YC-1,one inhibitor for targeting HIF-1?.The levels of HIF-1? and BCL-2 proteins in irradiated cells were increased under normoxia.On the other hand,the levels of HIF-1? and BCL-2,under hypoxia,were decreased by exposure to irradiation in high doses.Likewise,the reduction of HIF-1? and BCL-2 in irradiated cells could be found by YC-1 pretreatment.The doubling time of ACC-2/M-HIF-1? cells showed one shorter time compared with those of other three cells.Moreover,the doubling times of all four cells were prolonged when they were exposed to irradiation.Simultaneously,ACC-2/M-HIF-1? exhibited the highest D0 value in all cells.Conclusion: The high level of HIF-1? protein could decrease the radiosensitivity of SACC cells.The mechanism might be involving with HIF-1?/BCL-2 signaling in SACC cells. |
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