In-Cheol Kang

Activation of hypoxia-inducible factor-1 regulates human histidine decarboxylase expression

Abstract.Histidine decarboxylase (HDC) catalyzes the formation of histamine from histidine. Histamine has various effects in physiological and pathological reactions, such as inflammation, cell growth, and neuro-transmission. We investigated the role of hypoxia-inducible factor (HIF)-1 on hypoxia-induced HDC expression in human mast cell line, HMC-1 cells and mouse bone marrow-derived mast cells (BMMCs). Hypoxia significantly increased histamine production. HDC expression and activity were induced by hypoxia. Additionally, when cells were transfected with a native form of HIF-1α, hypoxia could induce higher HDC expression than in the nontransfected cell. HIF-1 binding activity for HDC 5’ flanking region (HFR) was similar to that for the hypoxia-responsive element. Using HDC promoter deletion analysis, we also demonstrated that HFR was regulated by HIF-1 activation. In addition, depletion of HIF-1α prevents hypoxic induction of HDC in BMMCs. In conclusion, these results demonstrate that hypoxia induces HDC expression by transcriptional mechanisms dependent upon HIF-1.

Atractylenolide III, a sesquiterpenoid, induces apoptosis in human lung carcinoma A549 cells via mitochondria-mediated death pathway.

Pharmacological agents that are safe and can sensitize the lung cancer are urgently required. We investigated whether Atractylenolide III (ATL-III), the major component of Atractylodes rhizome can induce apoptosis of the lung carcinoma cells. ATL-III inhibited cell growth, increased lactate dehydrogenase release and modulated cell cycle on human lung carcinoma A549 cells. ALT-III induced the activation of caspase-3 and caspase-9 and cleavage of poly-(ADP)-ribose polymerase. ATL-III induced the release of cytochrome c, upregulation of bax expression, and translocation of apoptosis-inducing factor. In addition, ATL-III inhibited the proliferation and capillary tube formation of human umbilical vein endothelial cells. These data indicate that ATL-III is a potential candidate for treatment of human lung carcinoma.

A novel integrin α5β1 antagonistic peptide, A5-1, screened by Protein Chip system as a potent angiogenesis inhibitor

Integrin alpha5beta1 immobilized on a ProteoChip was used to screen new antagonistic peptides from multiple hexapeptide sub-libraries of the positional scanning synthetic peptide combinatorial library (PS-SPCL). The integrin alpha5beta1-Fibronectin interaction was demonstrated on the chip. A novel peptide ligand, A5-1 (VILVLF), with high affinity to integrin alpha5beta1 was identified from the hexapeptide libraries with this chip-based screening method on the basis of a competitive inhibition assay. A5-1 inhibits the integrin-fibronectin interaction in a dose-dependent manner (IC(50); 1.56+/-0.28 microM. In addition, it inhibits human umbilical vein endothelial cell proliferation, migration, adhesion, tubular network formation, and bFGF-induced neovascularization in a chick chorioallantoic membrane. These results suggest that A5-1 will be a potent inhibitor of neovascularization.

Site‐specific inhibition of integrin αvβ3‐vitronectin association by a ser‐asp‐val sequence through an Arg‐Gly‐Asp‐binding site of the integrin

A functional proteomic technology using protein chip and molecular simulation was used to demonstrate a novel biomolecular interaction between P11, a peptide containing the Ser‐Asp‐Val (SDV) sequence and integrin αvβ3. P11 (HSDVHK) is a novel antagonistic peptide of integrin αvβ3 screened from hexapeptide library through protein chip system. An in silico docking study and competitive protein chip assay revealed that the SDV sequence of P11 is able to create a stable inhibitory complex onto the vitronectin‐binding site of integrin αvβ3. The Arg‐Gly‐Asp (RGD)‐binding site recognition by P11 was site specific because the P11 was inactive for the complex formation of a denatured form of integrin–vitronectin. P11 showed a strong antagonism against αvβ3‐GRGDSP interaction with an IC50 value of 25.72±3.34 nM, whereas the value of GRGDSP peptide was 1968.73±444.32 nM. The binding‐free energies calculated from the docking simulations for each P11 and RGD peptide were −3.99 and −3.10 kcal/mol, respectively. The free energy difference between P11 and RGD corresponds to approximately a 4.5‐fold lower Ki value for the P11 than the RGD peptide. The binding orientation of the docked P11 was similar to the crystal structure of the RGD in αvβ3. The analyzed docked poses suggest that a divalent metal–ion coordination was a common driving force for the formation of both SDV/αvβ3 and RGD/αvβ3 complexes. This is the first report on the specific recognition of the RGD‐binding site of αvβ3 by a non‐RGD containing peptide using a computer‐assisted proteomic approach.

Pharmacoproteomic Analysis of a Novel Cell-permeable Peptide Inhibitor of Tumor-induced Angiogenesis

P11, a novel peptide ligand containing a PDZ-binding motif (Ser-Asp-Val) with high affinity to integrin αvβ3 was identified from a hexapeptide library (PS-SPCL) using a protein microarray chip-based screening system. Here, we investigated the inhibitory mechanism of P11 (HSDVHK) on tumor-induced angiogenesis via a pharmacoproteomic approach. P11 was rapidly internalized by, human umbilical vein endothelial cells (HUVECs) via an integrin αvβ3-mediated event. Caveolin and clathrin appeared to be involved in the P11 uptake process. The cell-penetrating P11 resulted in suppression of bFGF-induced HUVEC proliferation in a dose-dependent manner. Phosphorylation of extracellular-signal regulated kinase (ERK1/2) and mitogen-activated protein kinase kinase (MEK) in bFGF-stimulated HUVECs was inhibited by cell-permeable P11. Proteomic analysis via antibody microarray showed up-regulation of p53 in P11-treated HUVECs, resulting in induction of apoptosis via activation of caspases-3, -8, and -9. Several lines of experimental evidence strongly suggest that the molecular mechanism of P11, a novel anti-angiogenic agent, inhibits bFGF-induced HUVEC proliferation via mitogen-activated protein kinase kinase and extracellular-signal regulated kinase inhibition as well as p53-mediated apoptosis related with activation of caspases.

Rosmarinic acid, active component of Dansam-Eum attenuates ototoxicity of cochlear hair cells through blockage of caspase-1 activity.

Cisplatin causes auditory impairment due to the apoptosis of auditory hair cells. There is no strategy to regulate ototoxicity by cisplatin thus far. Dansam-Eum (DSE) has been used for treating the central nerve system injury including hearing loss in Korea. However, disease-related scientific investigation by DSE has not been elucidated. Here, we demonstrated that DSE and its component rosmarinic acid (RA) were shown to inhibit apoptosis of the primary organ of Corti explants as well as the auditory cells. Administration of DSE and RA reduced the thresholds of the auditory brainstem response in cisplatin-injected mice. A molecular docking simulation and a kinetic assay show that RA controls the activity of caspase-1 by interaction with the active site of caspase-1. Pretreatment of RA inhibited caspase-1 downstream signal pathway, such as the activation of caspase-3 and 9, release of cytochrome c, translocation of apoptosis-inducing factor, up-regulation of Bax, down-regulation of Bcl-2, generation of reactive oxygen species, and activation of nuclear factor-κB. Anticancer activity by cisplatin was not affected by treatment with RA in SNU668, A549, HCT116, and HeLa cells but not B16F10 cells. These findings show that blocking a critical step by RA in apoptosis may be useful strategy to prevent harmful side effects of ototoxicity in patients with having to undergo chemotherapy.

Anti-angiogenic effects of the water extract of HangAmDan (WEHAD), a Korean traditional medicine.

We investigated the anti-angiogenic effects of the water extract of HangAmDan (WEHAD), which is a crude extract of nine Korean medicinal substances of animal and plant origin. In human umbilical vein endothelial cells, WEHAD significantly inhibited bFGF-induced proliferation, adhesion, migration, and capillary tube formation. We used an antibody array to perform an analysis of signaling proteins, which showed up-regulated expression of various proteins including RAD51, RAD52, and p73, and down-regulated expression of pFAK. Blood vessel formation in a chick chorioallantoic membrane (CAM) treated with WEHAD was markedly reduced in length compared with a PBS-treated control group. These results suggest that inhibition of angiogenesis by WEHAD may be the mechanism of action for the anti-cancer effects of HAD.

Antidepressant effect of Stillen

Stillen™ has been used to treat patients with gastric mucosal ulcers and has an anti-inflammatory effect. It is well-known that neuro-inflammatory reactions are related to depression. Here we evaluated the antidepressant-like effect of Stillen™ on mice subjected to the forced swimming test (FST). Stillen™ and eupatilin (a major component of Stillen™) significantly decreased immobility times compared with the FST control group. In the Stillen™-administered group, increased levels of 5-hydroxytryptamine (serotonin) and brain-derived neurotrophic factor protein were observed in the hippocampus. Nissl bodies also increased in the hippocampus neuronal cytoplasm of the Stillen™-administered group. Stillen™ decreased levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (at the mRNA and protein levels) in the hippocampus and serum, compared with the control group. In addition, the mRNA expression of estrogen receptor-β increased after Stillen™ administration in the hippocampus. These findings suggest that Stillen™ should be viewed as a candidate antidepressant.

Anti-angiogenic Function of a Korean Ginseng and Toad Venom Complex, Doksamsumsu-dan (DSSSD) Analyzed by a Forwarded Phase Antibody Microarray

We investigated anti-angiogenic effects of Korean Ginseng and Toad venom complex, Doksamsumsu- dan (DSSSD) using a Forwarded Phase Protein Array (FPPA) technology. DSSSD significantly inhibited bFGF-induced the proliferation and migration of human umbilical vein endothelial cell (HUVEC)s in a dose-dependent manner. FACS analysis was carried out to confirm this inhibition by demonstrating increase of apoptosis in HUVECs treated with DSSSD. The cell apoptosis was due to stimulating Bid expression by western blotting analysis. Blood vessel formation in a chick chorioallantoic membrane (CAM) treated with DSSSD was markedly suppressed compared with a PBS-treated control group. To investigate more detail the mode-of-action mechanism of DSSSD, we used a FPPA-based antibody microarray to analyze differential expression profiling of cellular signaling proteins. We found up-regulated expression of SAM 68, a RNAbinding protein known to be involved in cell proliferation, migration, and apoptosis. These results suggest that inhibition of angiogenesis by DSSSD may be one of anti-cancer effects of DSSSD.

ProteoChip-based library screening of integrin α5β1 antagonists from korean medicinal plant extracts

Integrins consist of transmembrane glycoproteins noncovalently associated to form αβ heterodimers. Various α/β associations determine binding specieficities for cell surface molecules of the immunoglobulin superfamily as well as for extracellular matrix components. Through their cytoplasmic domains, integrins are responsible for the transmission of signals between the intracellular and the extracellular environment. We immobilized an integrin α5β1 microar-ray on a ProteoChip to screen Korean medicinal plant extracts for binding activity. The microar-ray preserved the integrin α5β1-fibronectin interaction, and was suppressed by the synthetic RGD peptide. We identified ten extracts with high integrin affinity using a high-throughput, competitive inhibition assay. We also demonstrate the biological function of these extracts in HUVECs.