• Molecules and Cells
• /
• v.37 no.2
• /
• pp.178-186
• /
• 2014

Differential transcription of the clusterin (CLU) gene yields two CLU isoforms, a nuclear form (nCLU) and a secretory form (sCLU), which play crucial roles in prostate tumorigenesis. Pro-apoptotic nCLU and anti-apoptotic sCLU have opposite effects and are differentially expressed in normal and cancer cells; however, their regulatory mechanisms at the transcriptional level are not yet known. Here, we examined the transcriptional regulation of nCLU in response to hypoxia. We identified three putative hypoxia response elements (HREs) in the human CLU promoter between positions -806 and +51 bp. Using a luciferase reporter, electrophoretic gel mobility shift, and chromatin immunoprecipitation assays, we further showed that hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$) bound directly to these sites and activated transcription. Exposure to the hypoxia-mimetic compound $CoCl_2$, incubation under 1% $O_2$ conditions, or overexpression of HIF-$1{\alpha}$ enhanced nCLU expression and induced apoptosis in human prostate cancer PC3M cells. However, LNCaP prostate cancer cells were resistant to hypoxia-induced cell death. Methylation-specific PCR analysis revealed that the CLU promoter in PC3M cells was not methylated; in contrast, the CLU promoter in LNCap cells was methylated. Co-treatment of LNCaP cells with $CoCl_2$ and a demethylating agent promoted apoptotic cell death through the induction of nCLU. We conclude that nCLU expression is regulated by direct binding of HIF-$1{\alpha}$ to HRE sites and is epigenetically controlled by methylation of its promoter region.

• Molecules and Cells
• /
• v.37 no.6
• /
• pp.487-496
• /
• 2014

Angiotensinogen (AGT), the precursor of angiotensin I, is known to be involved in tumor angiogenesis and associated with the pathogenesis of coronary atherosclerosis. This study was undertaken to determine the role played by AGT in endothelial progenitor cells (EPCs) in tumor progression and metastasis. It was found that the number of EPC colonies formed by AGT heterozygous knockout ($AGT^{+/-}$) cells was less than that formed by wild-type (WT) cells, and that the migration and tube formation abilities of $AGT^{+/-}$ EPCs were significantly lower than those of WT EPCs. In addition, the gene expressions of vascular endothelial growth factor (VEGF), Flk1, angiopoietin (Ang)-1, Ang-2, Tie-2, stromal derived factor (SDF)-1, C-X-C chemokine receptor type 4 (CXCR4), and of endothelial nitric oxide synthase (eNOS) were suppressed in $AGT^{+/-}$ EPCs. Furthermore, the expressions of hypoxia-inducible factor (HIF)-$1{\alpha}$and $-2{\alpha}$ were downregulated in $AGT^{+/-}$ early EPCs under hypoxic conditions, suggesting a blunting of response to hypoxia. Moreover, the activation of Akt/eNOS signaling pathways induced by VEGF, epithelial growth factor (EGF), or SDF-$1{\alpha}$ were suppressed in $AGT^{+/-}$ EPCs. In $AGT^{+/-}$ mice, the incorporation of EPCs into the tumor vasculature was significantly reduced, and lung tumor growth and melanoma metastasis were attenuated. In conclusion, AGT is required for hypoxia-induced vasculogenesis.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.21 no.3
• /
• pp.741-747
• /
• 2007

This study evaluated neuroprotective effects of Yanggyuksanhwa-tang (YST), which have been known to be efficacy in the treatment of the stroke and diabetes. on focal cerebral ischemia of diabetic rats. On primary experiment, diabetic condition in rats was induced by streptozotocin injection, then, focal cerebral ischemia was induced by the middle cerebral artery occlusion (MCAO) under the diabetic condition. Then neuroprotective effect of YST was observed with changes of infarct size and volume, expressions of c-Fos, Bax, and hypoxia inducible factor (HIF)-1${\alpha}$ in the brain tissues by using 2% 2,3,5-triphenyltetrazolium chloride (TTC) staining and immunohistochemistry. YST treatment showed a significant decrease of infarct size and volume induced by MCAO in diabetic rats. YST treatment showed a significant decrease of c-Fos and Bax positive neurons in cortex penumbra. YST treatment showed a decrease of HIF-l${\alpha}$ positive neurons in cortex penumbra, but it was not significant statistically. These results suggest that YST has effects on neuroprotection against cerebral infarct under diabetic condition. And it is supposed that neuroprotective effect of YST reveals by anti-apoptosis mechanism.

• Molecules and Cells
• /
• v.21 no.1
• /
• pp.1-6
• /
• 2006

Bcl-2/adenovirus E1B 19 kDa-interacting protein 3 (BNIP3) is a mitochondrial pro-apoptotic protein that has a single Bcl-2 homology 3 (BH3) domain and a COOH-terminal transmembrane (TM) domain. Although it belongs to the Bcl-2 family and can heterodimerize with Bcl-2, its pro-apoptotic activity is distinct from those of other members of the Bcl-2 family. For example, cell death mediated by BNIP3 is independent of caspases and shows several characteristics of necrosis. Furthermore, the TM domain, but not the BH3 domain, is required for dimerization, mitochondrial targeting and pro-apoptotic activity. BNIP3 plays an important role in hypoxia-induced death of normal and malignant cells. Its expression is markedly increased in the hypoxic regions of some solid tumors and appears to be regulated by hypoxia-inducible factor (HIF), which binds to a site on the BNIP3 promoter. Silencing, followed by methylation, of the BNIP3 gene occurs in a significant proportion of cancer cases, especially in pancreatic cancers. BNIP3 also has a role in the death of cardiac myocytes in ischemia. Further studies of BNIP3 should provide insight into hypoxic cell death and may contribute to improved treatment of cancers and cardiovascular diseases.

• Journal of Korean Medicine Rehabilitation
• /
• v.15 no.1
• /
• pp.25-37
• /
• 2005

목적 : 진피(Citus Unshiu, CU)는 실험적으로 항산화, 항알러지, 항종양 효과 등이 있다고 보고되고 있다. 본 연구에서는 비만세포에서 PMA와 A23187에 의하여 유도된 싸이토카인의 증가에 대한 진피 추출물의 억제 효과와 그 기전을 알아보고자 한다. 방법 : PMA+A23187에 의한 싸이토카인 생성에 대한 진피 추출물의 억제효과 기전을 조사하기 위하여 진피를 처리한 후 $IL-1{\beta}$, IL-8, $TNF-{\alpha}$의 생산 및 혈관내피성장인자 (VEGF), 과립구 대식구 군집 자극 인자 (GM-CSF), 저산소 유도 인자(HIF-1)의 발현을 조사하였다. 결과 : 실험에서 PMA와 A23187을 처리한 경우 대조군에 비하여 $IL-1{\beta}$, IL-8, $TNF-{\alpha}$의 생산을 유의하게 증가시켰으나 진피 추출물을 처리한 군에서는 유의하게 억제되었다. 특히 $IL-1{\beta}$의 생성은 $103.7{\pm}5%$, IL-8 생성은 $34.6{\pm}7%$, $TNF-{\alpha}$의 생성은 $85.9{\pm}4.5%$ 억제되었다. (P<0.05). 또한 진피 추출물은 PMA와 A23187에 의하여 증가한 VEGF, GM-CSF, $HIF-1{\alpha}$의 발현 증가를 억제하였다 (약 90.9%의 VEGF, 61.6%의 GM-CSF). 결론 : 이러한 결과는 진피가 염증반응에 대한 HIF-1의 억제자로 작용할 수 있으면, 진피가 비만세포 매개성 염증 질환 치료제의 후보 물질이 될 것으로 사료된다.

• Tissue Engineering and Regenerative Medicine
• /
• v.15 no.6
• /
• pp.793-801
• /
• 2018

BACKGROUND: The aim of this study was to evaluate the combined effect of low-level laser treatment (LLLT) and recombinant human bone morphological protein-2 (rhBMP-2) applied to hypoxic-cultured MC3T3-E1 osteoblastic cells and to determine possible signaling pathways underlying differentiation and mineralization of osteoblasts under hypoxia. METHODS: MC3T3-E1 cells were cultured under 1% oxygen tension for 72 h. Cell cultures were divided into four groups: normoxia control, low-level laser (LLL) alone, rhBMP-2 combined with LLLT, and rhBMP-2 under hypoxia. Laser irradiation was applied at 0, 24, and 48 h. Cells were treated with rhBMP-2 at 50 ng/mL. Alkaline phosphatase activity was measured at 3, 7, and 14 days to evaluate osteoblastic differentiation. Cell mineralization was determined with Alizarin red S staining at 7 and 14 days. Western blot assays were performed to evaluate whether p38/protein kinase D (PKD) signaling was involved. RESULTS: The results indicate that LLLT and rhBMP-2 synergistically increased alkaline phosphatase (ALP) activity and mineralization. Western blot analyses showed that expression of type I collagen, runt-related transcription factor 2 (RUNX2), and Osterix (Osx), increased and expression of hypoxia-inducible factor 1-alpha ($HIF-1{\alpha}$), decreased more in the LLLT and rhBMP-2 combined group than in the rhBMP-2 or LLL alone groups. Moreover, LLLT and rhBMP-2 stimulated p38 phosphorylation and rhBMP-2 and LLLT increased Prkd1 phosphorylation. CONCLUSION: Combined treatment with rhBMP-2 and LLL induced differentiation and mineralization of hypoxic-cultured MC3T3-E1 osteoblasts by activating p38/PKD signaling in vitro.

• Molecules and Cells
• /
• v.43 no.11
• /
• pp.935-944
• /
• 2020

Aryl hydrocarbon receptor nuclear translocator (ARNT) plays an essential role in maintaining cellular homeostasis in response to environmental stress. Under conditions of hypoxia or xenobiotic exposure, ARNT regulates the subset of genes involved in adaptive responses, by forming heterodimers with hypoxia-inducible transcription factors (HIF1α and HIF2α) or aryl hydrocarbon receptor (AhR). Here, we have shown that ARNT interacts with DDB1 and CUL4-associated factor 15 (DCAF15), and the aryl sulfonamides, indisulam and E7820, induce its proteasomal degradation through Cullin-RING finger ligase 4 containing DCAF15 (CRL4^DCAF15) E3 ligase. Moreover, the two known neo-substrates of aryl sulfonamide, RNA-binding motif protein 39 (RBM39) and RNA-binding motif protein 23 (RBM23), are not required for ARNT degradation. In line with this finding, aryl sulfonamides inhibited the transcriptional activities of HIFs and AhR associated with ARNT. Our results collectively support novel regulatory roles of aryl sulfonamides in both hypoxic and xenobiotic responses.

• International Journal of Oral Biology
• /
• v.38 no.3
• /
• pp.111-119
• /
• 2013

Objective. To investigate the effects of the hypoxia inducible factor-1 (HIF-1) activation-mimicking agent cobalt chloride ($CoCl_2$) on the osteogenic differentiation of human mesenchymal stem cells (hMSCs) and elucidate the underlying molecular mechanisms. Study design. The dose and exposure periods for $CoCl_2$ in hMSCs were optimized by cell viability assays. After confirmation of $CoCl_2$-induced HIF-$1{\alpha}$ and vascular endothelial growth factor expression in these cells by RT-PCR, the effects of temporary preconditioning with $CoCl_2$ on hMSC osteogenic differentiation were evaluated by RT-PCR analysis of osteogenic gene expression, an alkaline phosphatase (ALP) activity assay and by alizarin red S staining. Results. Variable $CoCl_2$ dosages (up to $500{\mu}M$) and exposure times (up to 7 days) on hMSC had little effect on hMSC survival. After $CoCl_2$ treatment of hMSCs at $100{\mu}M$ for 24 or 48 hours, followed by culture in osteogenic differentiating media, several osteogenic markers such as Runx-2, osteocalcin and osteopontin, bone sialoprotein mRNA expression level were found to be up-regulated. Moreover, ALP activity was increased in these treated cells in which an accelerated osteogenic capacity was also verified by alizarin red S staining. Conclusions. The osteogenic differentiation potential of hMSCs could be preserved and even enhanced by $CoCl_2$ treatment.

• Journal of Life Science
• /
• v.22 no.1
• /
• pp.41-48
• /
• 2012

Bee venom (BV) has been used in medicine to treat a variety of diseases including arthritis, rheumatism, and various cancers. Recent reports indicate that BV has anti-angiogenic effects, but the precise molecular mechanism underlying the effects of BV against colorectal cancer remains to be elucidated. We examined the effects of BV and its major components (melittin and apamin) on tumor angiogenesis and found that BV significantly decreased protein levels of hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$), an important factor involved in angiogenesis and tumor progression, in human colorectal carcinoma HCT116 cells. BV also suppressed the transcription of HIF-$1{\alpha}$ under hypoxia, leading to a decrease in the expression of vascular endothelial growth factor (VEGF), a major target gene of HIF-$1{\alpha}$. We also found that these effects were mainly elicited by apamin, but not melittin. BV specifically inhibited the phosphorylation of ERK1/2 without changing the total levels of this protein, but had no effect on kinases of p38/JNK and AKT. Our results suggest that BV may inhibit human colorectal cancer progression and angiogenesis by inhibiting HIF-$1{\alpha}$ and VEGF expression, thereby providing a novel potential mechanism for the anticancer action of BV.

• Molecules and Cells
• /
• v.38 no.6
• /
• pp.528-534
• /
• 2015

Hypoxia-inducible factor (HIF) is a key regulator of tumor growth and angiogenesis. Recent studies have shown that, BIX01294, a G9a histone methyltransferase (HMT)-specific inhibitor, induces apoptosis and inhibits the proliferation, migration, and invasion of cancer cells. However, not many studies have investigated whether inhibition of G9a HMT can modulate HIF-$1{\alpha}$ stability and angiogenesis. Here, we show that BIX01294 dose-dependently decreases levels of HIF-$1{\alpha}$ in HepG2 human hepatocellular carcinoma cells. The half-life of HIF-$1{\alpha}$, expression of proline hydroxylase 2 (PHD2), hydroxylated HIF-$1{\alpha}$ and von Hippel-Lindau protein (pVHL) under hypoxic conditions were decreased by BIX01294. The mRNA expression and secretion of vascular endothelial growth factor (VEGF) were also significantly reduced by BIX01294 under hypoxic conditions in HepG2 cells. BIX01294 remarkably decreased angiogenic activity induced by VEGF in vitro, ex vivo, and in vivo, as demonstrated by assays using human umbilical vein endothelial cells (HUVECs), mouse aortic rings, and chick chorioallantoic membranes (CAMs), respectively. Furthermore, BIX01294 suppressed VEGF-induced matrix metalloproteinase 2 (MMP2) activity and inhibited VEGF-induced phosphorylation of VEGF receptor 2 (VEGFR-2), focal adhesion kinase (FAK), and paxillin in HUVECs. In addition, BIX01294 inhibited VEGF-induced formation of actin cytoskeletal stress fibers. In conclusion, we demonstrated that BIX01294 inhibits HIF-$1{\alpha}$ stability and VEGF-induced angiogenesis through the VEGFR-2 signaling pathway and actin cytoskeletal remodeling, indicating a promising approach for developing novel therapeutics to stop tumor progression.