EGF On The Function And Expression Of HIF-1α In Esophageal Squamous Cancer Cells

BackgroudEsophageal cancer is commonly seen in China, with high mortality and poor prognosis. Among eaophageal cancers,esophageal squmaous cell carcinoma (ESCC)account for approximately95%.Recently many researches have revealed that hypoxia-inducible factor1alpha(HIF-1α) is involved in ESCC.As an important transcriptional factor, HIF-1α plays a key role in angiogenesis, invasion and metastasis in ESCC. In signaling pathways regulated by HIF-1α, the most important thing is that PI3K/AKT and MAPK/ERK pathway. MAPK/ERK pathway is mainly through the HIF-1α phosphorylation to activate the transcription activity, while the PI3K/AKT regulation of HIF-1α changes in protein levels. The epidermal growth factor (epidermal growth factor, EGF) under the condition of constant oxygen, can pass and the corresponding tyrosine kinase receptor, activation of PI3K/AKT signal transduction pathways induced the expression of HIF-1α protein.ObjetivesEsophageal cancer cells use EGF pretreatment, to activate the PI3K/AKT pathway, and study the dependency of PI3K/AKT signal transduction pathway of esophageal cancer cells HIF-1alpha protein expression, the influence of and further affect the esophageal cancer angiogenesis mimicry.Methods1.Eca109and TE13cells were devided into two groups,and cultured under normoxic and hypoxic conditions for proper time. 2.The expressions of HIF-la, EphA2, VE-cadherin, Laminin5y2and MMP-2protein were detected by Western blot.3.The expressions of HIF-la,EphA2/ECK, VE-cadherin, and MMP-2RNA were detected by RT-PCR.4.300μl matrigel was added into every well of24-well plate. After the matrigel had solidified, each group cells were seeded into the24-well plate by5×105per well, then incubate for6and12hours. Observe and count the number of capillary structure of each group cells.Results1.Either under normoxia or under hypoxia, the expression of HIF-la protein up-regulated with EGF.compared with the control groups(P<0.05).As the same time,the expressions of EphA2, VE-cadherin, Laminin5y2protein up-regulated (P<0.05). the expression of MMP2had an increasing trend but no statistical significance (P>0.05).2. The expression of HIF-la mRNA up-regulated with EGF.compared with the control groups(P<0.05). As the same time,the expressions of EphA2, VE-cadherin, mRNA up-regulated (P<0.05). the expression of MMP2had an increasing trend but no statistical significance (P>0.05).3.The tubule-forming ability of EGF groups was significantly higher in normoxia and hypoxia(P<0.05).Conclusions1. EGF could up-regulate the expression of HIF-1α,EphA2, VE-cadherin and Laminin5y2in Esophageal squamous cancer cell under normoxia and hypoxia environment.2.Esophageal squamous cancer cell lines Eca-109, TE13are all capable of forming VM structures in vitro under normoxia and hypoxia environment. EGF can promote their vasculogenic mimicry formation efficiently.3.In esophageal cancer cells, the dependency of PI3K/AKT signal transduction pathways in the regulation of HIF-1alpha protein levels and, in turn, affect the esophageal cancer angiogenesis mimicry, EGF may by promoting the activation of PI3K/AKT pathway regulating HIF-1alpha protein levels and, in turn, affects esophageal cancer angiogenesis mimicry.