Kyung-Hee Kim

Transglutaminase 2 inhibition found to induce p53 mediated apoptosis in renal cell carcinoma

Renal cell carcinoma (RCC), the predominant form of kidney cancer, is characterized by high resistance to radiation and chemotherapy. This study shows that expression of protein cross‐linking enzyme transglutaminase 2 (TGase 2) is markedly increased in 7 renal cell carcinoma (RCC) cell lines in comparison to HEK293 and other cancer cell lines, such as NCI 60. However, the key role of TGase 2 in RCC was not clear. The down‐regulation of TGase 2 was found to stabilize p53 expression, thereby inducing a 3‐ to 10‐fold increase in apoptosis for 786‐O, A498, CAKI‐1, and ACHN cell lines by DAPI staining. MEF cells from TGase 2–/– mice showed stabilized p53 under apoptotic stress to compare to MEFs from wild‐type mice. TGase 2 directly cross links the DNA binding domain of p53, leading to p53 depletion via autophagy in RCC. TGase 2 and p53 expression showed an inverse relationship in RCC cells. This finding implies that induced expression of TGase 2 promotes tumor cell survival through p53 depletion in RCC.—Ku, B.M., Kim, D.‐S., Kim, K.‐H., Yoo, B.C., Kim, S.‐H., Gong, Y.‐D., Kim, S.‐Y., Transglutaminase 2 inhibition found to induce p53 mediated apoptosis in renal cell carcinoma. FASEB J. 27, 3487–3495 (2013). www.fasebj.org

Adenosine dialdehyde suppresses MMP-9-mediated invasion of cancer cells by blocking the Ras/Raf-1/ERK/AP-1 signaling pathway

Adenosine dialdehyde (AdOx) inhibits transmethylation by the accumulation of S-adenosylhomocysteine (SAH), a negative feedback inhibitor of methylation, through the suppression of SAH hydrolase (SAHH). In this study, we aimed to determine the regulatory effect of AdOx on cancer invasion by using three different cell lines: MDA-MB-231, MCF-7, and U87. The invasive capacity of these cells in the presence (MCF-7) or absence (MDA-MB-231 and U87) of phorbal 12-myristate 13-acetate (PMA) was strongly decreased by AdOx treatment. Furthermore, the expression, secretion, and activation of matrix metalloproteinase (MMP)-9, a critical enzyme regulating cell invasion, in these cells were diminished by AdOx treatment. AdOx strongly suppressed AP-1-mediated luciferase activity and, in parallel, reduced the translocation of c-Fos and c-Jun into the nucleus. AdOx was shown to block a series of upstream AP-1 activation signaling complexes composed of extracellular signal-related kinase (ERK), mitogen-activated protein ERK kinase (MEK)1/2, Raf-1, and Ras, as assessed by measuring the levels of the phosphorylated and membrane-translocated forms. Furthermore, we found that suppression of SAHH by siRNA and 3-deazaadenosine, knock down of isoprenylcysteine carboxyl methyltransferase (ICMT), and treatment with SAH showed inhibitory patterns similar to those of AdOx. Therefore, our data suggest that AdOx is capable of targeting the methylation reaction regulated by SAHH and ICMT and subsequently downregulating MMP-9 expression and decreasing invasion of cancer cells through inhibition of the Ras/Raf-1/ERK/AP-1 pathway.

Anti-Inflammatory and Antinociceptive Activities of Anthraquinone-2-Carboxylic Acid

Anthraquinone compounds are one of the abundant polyphenols found in fruits, vegetables, and herbs. However, the in vivo anti-inflammatory activity and molecular mechanisms of anthraquinones have not been fully elucidated. We investigated the activity of anthraquinones using acute inflammatory and nociceptive experimental conditions. Anthraquinone-2-carboxylic acid (9,10-dihydro-9,10-dioxo-2-anthracenecarboxylic acid, AQCA), one of the major anthraquinones identified from Brazilian taheebo, ameliorated various inflammatory and algesic symptoms in EtOH/HCl- and acetylsalicylic acid- (ASA-) induced gastritis, arachidonic acid-induced edema, and acetic acid-induced abdominal writhing without displaying toxic profiles in body and organ weight, gastric irritation, or serum parameters. In addition, AQCA suppressed the expression of inflammatory genes such as cyclooxygenase- (COX-) 2 in stomach tissues and lipopolysaccharide- (LPS-) treated RAW264.7 cells. According to reporter gene assay and immunoblotting analyses, AQCA inhibited activation of the nuclear factor- (NF-) κB and activator protein- (AP-) 1 pathways by suppression of upstream signaling involving interleukin-1 receptor-associated kinase 4 (IRAK1), p38, Src, and spleen tyrosine kinase (Syk). Our data strongly suggest that anthraquinones such as AQCA act as potent anti-inflammatory and antinociceptive components in vivo, thus contributing to the immune regulatory role of fruits and herbs.

Depletion of cathepsin D by transglutaminase 2 through protein cross-linking promotes cell survival.

Transglutaminase 2 (TGase 2) promotes nuclear factor-κB (NF-κB) activity through depletion of the inhibitory subunit of NF-κB (I-κBα) via protein cross-linking, leading to resolution of inflammation. Increased expression of TGase 2 contributes to inflammatory disease pathogenesis via constitutive NF-κB activation. Conversely, TGase 2 inhibition often reverses inflammation in animal models. The role of TGase 2 in apoptosis remains less clear, as both pro- and anti-apoptotic functions of TGase 2 have been demonstrated under different experimental conditions. Apoptosis is intact in a TGase 2 knock out mouse (TGase2−/−), which is phenotypically normal. However, upon exposure to tumor necrosis factor (TNF)-α-induced apoptotic stress, mouse embryonic fibroblasts (MEFs) from TGase2−/− mice were more sensitive to cell death than MEFs from wild-type (TGase 2+/+) mice. In the current study, to explore the role of TGase 2 in apoptosis, TGase 2-binding proteins were identified by LC/MS. TGase 2 was found to associate with cathepsin D (CTSD). Binding of TGase 2 to CTSD resulted in the depletion of CTSD via cross-linking in vitro as well as in MEFs, leading to decreased levels of apoptosis. Furthermore, cytoplasmic CTSD levels were higher in MEFs from TGase 2−/− mice than in those from TGase 2+/+ mice, as were caspase 3 activation and poly (ADP-ribose) polymerase (PARP) processes. These results suggest that TGase 2, while not previously implicated as a major regulatory factor in apoptosis, may regulate the balance between cell survival and cell death through the modulation of CTSD levels.

Induction of LGR5 by H2O2 treatment is associated with cell proliferation via the JNK signaling pathway in colon cancer cells

Recently, the leucine-rich repeat G protein-coupled receptor 5 (LGR5/GPR49) was identified as a potential marker of intestinal stem cells in human. The LGR5 is known as a Wnt signaling target gene, and its expression pattern is related with β-catenin mutation. H2O2 is a member of reactive oxygen species (ROS) and regulates metabolism, aging, apoptosis and the intensity of growth factor signaling. In addition, it acts as a negative or positive regulator of Wnt signaling. However, the effect of H2O2 on Wnt signaling and its target gene LGR5 is not clear. In this study, we investigated the effects of ROS on cancer stem cells, in colorectal cancer cells. Colorectal cancer cells were treated with exogenous H2O2, after which cellular responses and the expression of LGR5 were examined. In SNU-C2A cells, proliferation increased following treatment with 50-300xa0µM of H2O2, whereas cell viability significantly decreased after treatment with 600-900 µM of H2O2. Expression of heme oxygenase (HO)-1 and jun, which aid in the reduction of oxidative stress, were induced in the low dose H2O2-treated SNU-C2A cells. The LGR5 expression level was significantly increased following 50-300xa0µM H2O2 treatment; in addition, β-catenin was increased in H2O2-treated colon cancer cells. However, the increased β-catenin was detected not in the nucleus but in the cytoplasm, which means that β-catenin was stabilized in the cytoplasm and not translocated into the nucleus where it could function as a transcription factor for the expression of LGR5. In addition, there was no direct interaction between LGR5 and β-catenin. In this study, we found that LGR5 expression increased when cancer cells were treated with a low dose of H2O2. Our results indicate that the LGR5 increase resulted via activation of the JNK signaling pathway. The induction of LGR5 expression influenced cell proliferation in colorectal cancer cells.

HangAmDan-B, an Ethnomedicinal Herbal Mixture, Suppresses Inflammatory Responses by Inhibiting Syk/NF-κB and JNK/ATF-2 Pathways

HangAmDan-B (HAD-B) is a powdered mixture of eight ethnopharmacologically characterized folk medicines that is prescribed for solid masses and cancers in Korea. In view of the finding that macrophage-mediated inflammation is a pathophysiologically important phenomenon, we investigated whether HAD-B modulates inflammatory responses and explored the associated molecular mechanisms. The immunomodulatory activity of HAD-B in toll-like receptor-activated macrophages induced by lipopolysaccharide (LPS) was assessed by measuring nitric oxide (NO) and prostaglandin E(2) (PGE(2)) levels. To identify the specific transcription factors (such as nuclear factor [NF]-κB and signaling enzymes) targeted by HAD-B, biochemical approaches, including kinase assays and immunoblot analysis, were additionally employed. HAD-B suppressed the production of PGE(2) and NO in LPS-activated macrophages in a dose-dependent manner. Furthermore, the extract ameliorated HCl/EtOH-induced gastritis symptoms. Moreover, HAD-B significantly inhibited LPS-induced mRNA expression of inducible NO synthase and cyclooxygenase (COX)-2. Interestingly, marked inhibition of NF-κB and activating transcription factor was observed in the presence of HAD-B. Data from direct kinase assays and immunoblot analysis showed that HAD-B suppresses activation of the upstream signaling cascade involving spleen tyrosine kinase, Src, p38, c-Jun N-terminal kinase, and transforming growth factor β-activated kinase 1. Finally, kaempferol, but not quercetin or resveratrol was identified as a bioactive compound in HAD-B. Therefore, our results suggest that HAD-B possesses anti-inflammatory activity that contributes to its anticancer property.

Hydroxymethylglutaryl-coenzyme a synthase 2 expression is associated with chemoradiotherapy responses in colorectal cancer.

BACKGROUND: Preoperative chemoradiotherapy has become a standard treatment modality for locally advanced rectal cancer. Favorable long-term outcomes have been reported for patients with good responses to chemoradiotherapy. Therefore, predictive factors for chemoradiotherapy responses can be useful for their applicability to risk-adaptive therapy in patients with colorectal cancer. OBJECTIVE: The aim of this study was to investigate whether hydroxymethylglutaryl-coenzyme A synthase 2, a key enzyme in ketogenesis, is associated with the responses of colorectal cancer cells to chemoradiotherapy. DESIGN: Hydroxymethylglutaryl-coenzyme A synthase 2 was identified by a 2-dimensional gel electrophoresis –based proteome analysis. It was analyzed in 12 colorectal cancer cells for associations with radiation or 5-fluorouracil susceptibility by Western blotting, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium Bromide assay, and small interfering RNA transfection. Then, tumor tissues obtained from 45 patients with rectal cancer before chemoradiotherapy were analyzed by Western blotting for associations with chemoradiotherapy responses. RESULTS: Expression of hydroxymethylglutaryl-coenzyme A synthase 2 was significantly correlated with intrinsic radiation resistance of 12 cancer cells. Hydroxymethylglutaryl-coenzyme A synthase 2 expression was significantly affected by treatment with either 5-fluorouracil or radiation depending on cell types. The artificial suppression of hydroxymethylglutaryl-coenzyme A synthase 2 did not result in the change of chemoradiation susceptibility in colorectal cancer cells. Nevertheless, in multivariate analyses, hydroxymethylglutaryl-coenzyme A synthase 2 expression in rectal cancer tissues was shown to be a significant predictive factor for chemoradiotherapy responses, as evaluated in terms of tumor regression grade and downstaging. LIMITATIONS: Overall findings in vitro showed that the expression level of hydroxymethylglutaryl-coenzyme A synthase 2 was highly variable depending on colon cancer cell types, and it cannot directly affect on chemoradiotherapy responses. The molecular mechanism underpinning the association between hydroxymethylglutaryl-coenzyme A synthase expression and chemoradiotherapy responses needs to be elucidated through future research. CONCLUSIONS: Hydroxymethylglutaryl-coenzyme A synthase 2 was associated with the effects of chemoradiotherapy on human colorectal cancer cells. Pretreatment levels of hydroxymethylglutaryl-coenzyme A synthase 2 in rectal cancer may be useful in predicting the responses to chemoradiotherapy.

Inter-molecular crosslinking activity is engendered by the dimeric form of transglutaminase 2

Transglutaminase 2 (TGase 2) catalyzes a crosslink between protein bound-glutamine and -lysine. We proposed the mechanism of TGase 2 activation depends on conformation change from unfolded monomer to unfolded dimer. We found that TGase 2 has temperature-sensitive conformation change system at 30xa0°C. Small-angle X-ray scattering analysis showed that the enzyme was maintained as an unfolded monomer at temperatures below 30xa0°C, but changed to an unfolded dimer at over 30xa0°C. Mass analysis revealed that the C-terminus of TGase 2 was the critical region for dimerization. Furthermore, this conformational switch creates new biochemical reactivity that catalyzed inter-molecular crosslink at above 30xa0°C as an unfolded dimer of TGase 2 while catalyzed intra-molecular crosslink at below 30xa0°C as an unfolded monomer of TGase 2. The mechanism of TGase 2 activation depends on temperature-sensitive conformation change from unfolded monomer to unfolded dimer at over 30xa0°C. Furthermore, inter-molecular crosslinking activity is generated by the dimeric form of TGase 2. TGase 2 switches its conformation from a monomer to a dimer following a change in temperature, which engendered unique catalytic function of enzyme as inter-molecular crosslinking activity with calcium.

Investigation of early and advanced stages in ovarian cancer using human plasma by differential scanning calorimetry and mass spectrometry

Ovarian cancer is recognized with high mortality due to asymptomatic nature of the disease and difficulties in diagnosing early stage of the cancer. The present study evaluates the use of differential scanning calorimetry (DSC) in differentiating the severity of ovarian cancer from healthy women. 47 diseased women were subdivided into four stages with respect to clinical relevance and severity. Stages I–II were regarded as early stages and stages III–IV were regarded as advanced stages. The two average transition temperatures (Tm) increased with disease severity from 64.84 and 70.32xa0°C (healthy) to 68.46 and 75.24xa0°C (stage IV), respectively. Tm were increased depending on clinical groups. In addition, the change in heat capacity was also dependent on the disease severity. To further support and investigate the nature of the proposed interactions, matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis is employed. The results suggest the differences in peptide expression between early and advanced stage of ovarian cancer, affected abundant proteins in plasma. The combined DSC and MS approach was supportive in identifying a unique signature of ovarian cancer stages, and demonstrates the potential of DSC as a complementary diagnostic tool in the evaluation of early stage ovarian cancer.

Subjective health status and relative factors of old-old elderly of more than 75-year-old -Based on 2011 Korea National Health and Nutrition Examination Survey-

Abstract This study examined the health status and relative factors of 468 people of the latter stage of more than75-year-old in 2011 the Korean National Health and Nutritional Examination Survey. The subjective health status wereinfluenced significantly by sex(OR=0.456, 95%CI=0.257-0.805), occupation(OR=1.437, 95%CI=0.963-2.149), spouse(OR=0.673, 95%CI=0.443 -1.022), degree of stress(OR=0.476, 95% CI=0.309-0.730), depression(OR=0.410, 95% CI=0.238-0.704), subjective oral status(OR=1.874, 95% CI=1.332-2.643), smoking(OR=0.738, 95% CI= 0.523-1.039), drinking(OR=1.251, 95% CI=1.017-1.540), and waking practice(OR=1.698, 95% CI=1.188 -2.431). The results suggest that health education of active participations and publicity policies should be established and help improve the subjective health status in the latter stage of a 75-year-old. Key Words : Old-old elderly, Older than 75-year-old, Subjective health status 본 논문은 2012학년도 경북대학교 학술연구비에 의해 연구되었음. * Corresponding Author : Sung-Kook Lee(Kyungpook National Univ.) Tel: +82-53-420-4861 email: sunglee@knu.ac.krReceived March 13, 2014 Revised (1st May 21, 2014, 2nd June 5, 2014) Accepted July 10, 2014