The Research Of HIF-1α Promoting Migration And Invasion Of Hypopharyngeal Cancer FaDu Cells Under Hypoxic Condition

Hypopharyngeal cancer is a malignancy,accounting for about 5%of head and neck cancer.The most common pathogenic site is pyriform sinus region,followed by postcricoid region and pharynx posterior wall.Among the pathological patterns of hypopharyngeal carcinoma,squamous-cell carcinoma was most popular accounting for 95%of all cases.Due to the hidden anatomical location of the hypopharynx,early diagnosis is difficult.Most of the diagnoses are made in the middle and late stage,with lymph node metastasis,and high degree of malignancy.Therefore,it is of great importance to identify important factors for the occurrence and development of the tumor and discuss their mechanism of action for the diagnosis and treatment of hypopharyngeal cancer.Hypoxia microenvironment is a basic feature of most solid tumors.The adaptation to and rapid growth in hypoxic microenvironment rely on the extensive expression of a nuclear transcription factor-,hypoxia inducible factor(HIF-),which regulates hypoxic response in tumor cells.HIF-mediated intratumor hypoxia is an independent risk factor for poor tumor prognosis.HIF is a highly conserved transporter and plays an important role in oxygen homeostasis regulation.Researches have shown that there are three HIF-α subunits(HIF-1α,2α,and 3a)in mammals,of which HIF-la and HIF-2a have been generally studied.HIF-la and HIF-2a play their role by regulating different target genes,of angiogenesis,cell proliferation,energy metabolism,tumor survival and proliferation,invasion and metastasis,radio-chemotherapy tolerance,immune escape and so on.However,their specific mechanisms and pathways are still unclear.In this study we detected the expression of HIF-la in hypopharyngeal carcinoma,tissues and in FaDu cells,treated with HIF-1α activator and inhibitor.The effects of different treatment conditions on invasion and metastasis of hypopharyngeal carcinoma cells were observed.Objective:1.To investigate the expression of HIF-la in hypopharyngeal carcinoma and its correlation with clinical parameters.2.To investigate the effect of HIF-la activator CoCl2 and HIF-la inhibitor YC-1 on the expression of HIF-la protein and mRNA.3.To investigate the effect of different treatment conditions on the migration and invasion of FaDu cells.Methods:Paraffin sections were made from 33 hypopharyngeal carcinoma tissues and 23 normal tissues.The expressions of HIF-la protein were detected by immunohistochemistry.The hypopharyngeal carcinoma cell line FaDu was used as the experimental study object.HIF-la activator CoCl2 and inhibitor YC-1 were used to regulate the expression of HIF-la.The expression of HIF-laprotein after different treatment was detected by western blot.HIF-la mRNA was detected by RT-PCR,cell migration and invasion were observed by wound healing and transwell assays.Results:1.HIF-la protein was overexpressed in hypopharyngeal carcinoma tissues,could be detected by immunohistochemistry in both nuclear and cytoplasm of hypopharyngeal carcinoma cells,and positively correlated with pathological grading.2.Real-time PCR detection found that HIF-la mRNA expression in FaDu was not exactly parallel to its protein expression.3.HIF-1α protein expression increased significantly after 12 hr treatment with CoCl2 and decreased significantly after 12 hr treatment with YC-1.4.The migration and invasion abilities of FaDu cells were enhanced after CoCl2 treatment,but were attenuated after YC-1 treatment.Conclusions:1.HIF-la was overexpressed in the tissue of hypopharyngeal carcinoma,and positively correlated with pathological grading.2.The protein expression of HIF-1α was not completely parallel to the mRNA expression level,and the regulation of hif-1 by hypoxia conditions mainly occurred at the post-transcriptional level.3.Inhibiting the expression of HIF-la in FaDu cells can reduce the migration and invasion ability of cells,while promoting the expression of HIF-1α can increase the migration and invasion ability of cells.4.HIF-la plays an important role in the migration and invasion of hypopharyngeal cancer,and may be a new target for the diagnosis and treatment of it.