2034

EPAS1

endothelial PAS domain protein 1;EPAS1;endothelial PAS domain protein 1

EPAS-1|HIF-1-alpha-like factor|HIF-1alpha-like factor|HIF-2-alpha|HIF2-alpha|PAS domain-containing protein 2|basic-helix-loop-helix-PAS protein MOP2|class E basic helix-loop-helix protein 73|endothelial PAS domain-containing protein 1|hypoxia-inducible fa

2p21-p16

protein-coding

BACKGROUND: Adenoid cystic carcinoma (ACC) of salivary gland is characterized by advanced local invasion and distant metastasis. Intratumoral hypoxia was reported to be associated with epithelial-mesenchymal transition (EMT) regulators. The purpose of this study was to evaluate the relationship between hypoxia-inducible factor (HIF)-2alpha, TWIST2, and SIP1 expression and the invasion and metastasis in ACC of salivary gland. METHOD: In vitro we first detected the expression of HIF-2alpha, TWIST2, and SIP1 in two ACC cell lines by Western blot and real-time RT-PCR. Then, in vivo, a retrospective investigation of 121 patients with ACC from Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University between 1996 and 2005 was carried out using immunohistochemistry to analyze the association between the expression of these three factors and clinical-pathological factors of patients. RESULTS: The protein and mRNA levels of HIF-2alpha, TWIST2, and SIP1 in the high-metastasis cell line (ACC-M) were much higher than those of the low-metastasis cell line (ACC-2). The positive expression of HIF-2alpha, TWIST2, and SIP1 (71.07%, 42.98%, and 38.02%, respectively) was associated with the perineural invasion, the local recurrence, and distant metastasis of patients with ACC (P < 0.05). The patients with the positive coexpression of the three factors had a lower survival rate than those with the negative expression (P < 0.05). CONCLUSION: It is proposed that the elevated expression of HIF-2alpha, TWIST2, and SIP1 can contribute to invasion and metastasis of ACC, and there might be some correlation between the hypoxia microenvironment and EMT in ACC.

Intratumoral hypoxia has been correlated with distant metastatic potential. Two hypoxia inducible factors (HIFs), HIF-1alpha and HIF-2alpha, are induced by hypoxia, and high expression of these proteins has been correlated to angiogenesis and distant metastasis. Thymosin beta4 (Tbeta4) is frequently highly expressed in cancer, and this overexpression correlates with malignant progression. The objective of this study was to investigate the clinical correlation of HIF-alpha with Tbeta4 and the intracellular functional roles of Tbeta4 on HIF-alpha activation. We examined HIF-1alpha, HIF-2alpha and Tbeta4 expressions in clinical human breast carcinoma (n=70) by immunohistochemistry. We show that high expression of HIF-1alpha and HIF-2alpha strongly correlates with Tbeta4 expression (Pexpression of Tbeta4 correlates significantly with patients with lymph node metastasis (P<0.05) of human breast cancer. Additionally, we demonstrate that hypoxia up-regulates intracellular Tbeta4 protein, which then affects HIF-alpha activity, which is the key in regulating VEGF expression. We confirmed that hypoxia-induced intracellular Tbeta4 and HIF-alpha activities were reduced by interference of Tbeta4 expression using Tbeta4 shRNA lentivirus. Vascular epidermal growth factor (VEGF)-A, a well-recognized lymphangiogenic cytokine, was also down-regulated, but VEGF-C and VEGF-D expressions were not affected. These findings suggest that the overexpression of Tbeta4 is strongly associated with HIF-1alpha and HIF-2alpha expression and is also clinicopathologically involved with lymph node metastatic potential of breast cancer through the modulation of HIF-alphaactivation and induction of VEGF-A. Ultimately, these results highlight Tbeta4 as a potentially therapeutic target in malignant cancers.

CUB domain-containing protein 1 (CDCP1) is a transmembrane protein that is highly expressed in stem cells and frequently overexpressed and tyrosine-phosphorylated in cancer. CDCP1 promotes cancer cell metastasis. However, the mechanisms that regulate CDCP1 are not well-defined. Here we show that hypoxia induces CDCP1 expression and tyrosine phosphorylation in hypoxia-inducible factor (HIF)-2alpha-, but not HIF-1alpha-, dependent fashion. shRNA knockdown of CDCP1 impairs cancer cell migration under hypoxic conditions, whereas overexpression of HIF-2alpha promotes the growth of tumor xenografts in association with enhanced CDCP1 expression and tyrosine phosphorylation. Immunohistochemistry analysis of tissue microarray samples from tumors of patients with clear cell renal cell carcinoma shows that increased CDCP1 expression correlates with decreased overall survival. Together, these data support a critical role for CDCP1 as a unique HIF-2alpha target gene involved in the regulation of cancer metastasis, and suggest that CDCP1 is a biomarker and potential therapeutic target for metastatic cancers.

Hypoxia-inducible factor-1 (HIF-1) is a major determinant of invasion and metastasis in several tumor types. We previously reported that HIF-1alpha contributed to multidrug resistance in gastric cancer. However, the role of HIF-2alpha on the progression of gastric cancer is seldom reported. In this study, we first examined the possible role of HIF-1alpha and HIF-2alpha in the process of invasiveness and metastasis of gastric cancer, using immunohistochemistry of 80 gastric cancer tissues, western blot and real-time PCR of 8 fresh gastric cancer tissues. The results showed that HIF-1alpha and HIF-2alpha were significantly correlated with the clinical stage and were highly expressed in metastatic gastric cancers compared to nonmetastatic ones. Western blot analysis revealed that hypoxia (1% O(2), 8 h) induced HIF-1alpha and HIF-2alpha expression in different gastric cancer cell lines, including SGC7901, AGS, MGC803 and MKN45. Adhesion and invasion assays found that hypoxia caused an increase in adhesive and invasive abilities of gastric cancer cells. Small interfering (si) RNA against HIF-1alpha and HIF-2alpha in SGC7901 cells significantly inhibited hypoxia-induced adhesive and invasive abilities. Finally, the JNK inhibitor SP 600125 abolished hypoxia-induced HIF-1alpha and HIF-2alpha expression, and inhibited the adhesive and invasive abilities of gastric cancer cells exposed to hypoxia in a dose-dependent manner. Taken together, the present work suggested that HIF-1alpha and HIF-2alpha were involved in metastasis and invasion of gastric cancer cells under hypoxia, with the involvement of JNK signal pathway.

Malignant melanoma is characterized by a propensity for early lymphatic and hematogenous spread. The hypoxia-inducible factor (HIF) family of transcription factors is upregulated in melanoma by key oncogenic drivers. HIFs promote the activation of genes involved in cancer initiation, progression, and metastases. Hypoxia has been shown to enhance the invasiveness and metastatic potential of tumor cells by regulating the genes involved in the breakdown of the ECM as well as genes that control motility and adhesion of tumor cells. Using a Pten-deficient, Braf-mutant genetically engineered mouse model of melanoma, we demonstrated that inactivation of HIF1alpha or HIF2alpha abrogates metastasis without affecting primary tumor formation. HIF1alpha and HIF2alpha drive melanoma invasion and invadopodia formation through PDGFRalpha and focal adhesion kinase-mediated (FAK-mediated) activation of SRC and by coordinating ECM degradation via MT1-MMP and MMP2 expression. These results establish the importance of HIFs in melanoma progression and demonstrate that HIF1alpha and HIF2alpha activate independent transcriptional programs that promote metastasis by coordinately regulating cell invasion and ECM remodeling.

PURPOSE: Inactivation of von Hippel-Lindau (VHL) gene in clear-cell renal cell carcinoma (RCC) leads to increased levels of hypoxia-inducible factors (HIF) and overexpression of HIF target genes, such as VEGF and others. VEGF-targeted agents are standard in advanced clear-cell RCC but biomarkers of activity are lacking. EXPERIMENTAL DESIGN: We analyzed tumor tissue samples from metastatic clear-cell RCC patients who received pazopanib as part of clinical trial VEG102616. We evaluated several components of the VHL/HIF pathway: VHL gene inactivation (mutation and/or methylation), HIF-1alpha and HIF-2alpha immunohistochemistry staining, and HIF-1alpha transcriptional signature. We evaluated the association of these biomarkers with best overall response rate (ORR) and progression-free survival (PFS) to pazopanib, a standard first-line VEGF-targeted agent. RESULTS: The VEG102616 trial enrolled 225 patients, from whom 78 samples were available for tumor DNA extraction. Of these, 70 patients had VHL mutation or methylation. VHL gene status did not correlate with ORR or PFS. Similarly, HIF-1alpha (65 samples) and HIF-2alpha (66 samples) protein levels (high vs. low) did not correlate with ORR or PFS to pazopanib. The HIF-1alpha transcriptional signature (46 samples) was enriched in tumors expressing high HIF-1alpha levels. However, the HIF-1alpha gene expression signature was not associated with clinical outcome to pazopanib. CONCLUSIONS: In patients with advanced clear-cell RCC, several potential biomarkers along the VHL/HIF-1alpha/HIF-2alpha axis were not found to be predictive for pazopanib activity. Additional efforts must continue to identify biomarkers associated with clinical outcome to VEGF-targeted agents in metastatic RCC.

This study aimed to examine HIF-2alpha, TWIST, and CXCR4 expression in papillary thyroid carcinoma (PTC) and assesses the association of their expression with clinicopathological indicators. HIF-2alpha, TWIST, and CXCR4 protein expression in 129 PTCs, 61 nodular hyperplasia, and 118 normal thyroid tissue specimens was analyzed using immunohistochemistry. The protein expression levels of these three molecules were upregulated in PTCs. High protein expression of HIF-2alpha, TWIST, and CXCR4 was significantly correlated with lymph node metastasis (LNM) (P < 0.001). Furthermore, HIF-2alpha, TWIST, and CXCR4 protein expression was correlated with one another. Concomitant high expression of these molecules had stronger correlation with LNM than did each alone (P = 0.032 for HIF-2alpha/TWIST, P < 0.001 for HIF-2alpha/CXCR4, P = 0.018 for TWIST/CXCR4, and P < 0.001 for HIF-2alpha/TWIST/CXCR4). Additionally, HIF-2alpha, TWIST, and CXCR4 mRNA expression were assessed in 30 PTCs, 10 nodular hyperplasia, and 10 normal thyroid tissue specimens using real-time RT-PCR. TWIST and CXCR4 mRNA expression levels were up-regulated in PTCs, and high mRNA expression of TWIST and CXCR4 was significantly correlated with LNM (P = 0.005 and P = 0.010, resp.). These results demonstrated that the evaluation of HIF-2alpha, TWIST, and CXCR4 expression in PTC may be useful in predicting the risk of LNM.