▶ The Effects of Advanced Glycation End Products (AGEs)-Receptor for Advanced Glycation End Products (RAGE) Interaction on AGE-Mediated Intracellular Signal Pathway in Human Leukemia Cell Line

   We investigated the in vitro effect of advanced glycation end products (AGEs), the products of non-enzymatic glycation/oxidation of proteins/lipids which are regulated by receptor for AGE (RAGE) and accumulated during natural aging and greatly augmented in disorders such as diabetes, renal failure, and Alzheimer’s disease, on proliferation, cell cycle regulation, and intracellular signaling in human leukemia cell lines.

▶ Development of Anticancer Drugs

    We are searching the compounds with anticancer effects and investigating their antitumor mechanisms. In particular, we are focusing on vitamin D3 analogs, 2-pyrone derivatives, and ceramides. One vitamin D3 analog, and 2 pyrone derivatives, and 5 ceramides for lead compounds were developed. Now, more potent compounds are being searched under SAR study.  

▶ Mesenchyaml Stem Cell for Clinical Trial

     Mesenchymal stem cells or marrow stromal cells (MSC), are stem cells that can differentiate into osteoblasts, chondrocytes, myocytes, adipocytes, neuronal cells, and, as described lately, into beta-pancreatic islets cells. Mesenchymal stem cells (MSCs) have the capability for renewal and differentiation into various lineages of mesenchymal tissues. These features of MSCs attract a lot of attention from investigators in the context of cell-based therapies of several human diseases. Despite the fact that bone marrow represents the main available source of MSCs, the use of bone-marrow-derived cells is not always acceptable due to the high degree of viral infection and the significant drop in cell number and proliferative/differentiation capacity with age. Thus, the search for possible alternative MSC sources remains to be validated. Umbilical cord blood is a rich source of hematopoietic stem/progenitor cells, and does not contain mesenchymal progenitors. However, MSCs circulate in the blood of preterm fetuses and may be successfully isolated and expanded. Where these cells home at the end of gestation is not clear.

▲ up

▶ Molecular Mechanisms in the Cell Proliferation of Acute Myelogenous Leukemia Cells by Leptin

    Leptin, secreted as a product of the ob gene that is mainly produced by adipose tissue, has been involved in the regulation of energy metabolism. Recently, leptin has been suggested to induce cell proliferation in normal cells as well as various cancer cells including acute myelogenous leukemia (AML). However, the molecular mechanism of leptin as a proliferative effector is not poorly understood in AML. Therefore, we investigated the mechanisms of leptin-induced cancer cell proliferation by MTT, PCR, Western and shRNA in HEL human acute myeogenous leukemia cell line.

▶ Leptin-induced Peroxisome Proliferator-Activated Receptor-γ (PPAR-γ) Expression in Acute Myelogenous Leukemia

    The PPARγ is a member of the NHR superfamily. It functions as a transcription factor after it heterodimerizes with the RXR and binds to specific response elements called peroxisome proliferation response elements.  To act as a transcription factor, PPARγ requires activation by binding its ligand.

    The PPARγ ligands have anticancer activity against a wide variety of neoplastic cells in vitro. Other data suggest that PPARγ may behave as a tumor suppressor gene, although several compelling murine models, paradoxically, suggest that under selected circumstances, PPARγ ligands may stimulate cancer formation. Nevertheless, the bulk of studies  showed that PPARγ ligands do have antiproliferative activity against many transformed cells and may be helpful in the setting of adjuvant and chemopreventive treatments of several common tumors, including colon, prostate, and breast cancers.

    However, the effect of PPARγ ligands on myeloid leukemic growth and differentiation is modest. Leptin, an adipose-produced hormone, has been shown to reduce fat depot via decreasing food intake and increasing adipocyte thermogenesis.

    Expression of Leptin was reduced by Ligand/ PPARγ /RXR complex. So, the PPARγ signaling pathway could be related with Leptin in tuomorigenic process. However, the relationship of PPARγ and Leptin not well known in tumor. The aim of our study is to determine the relation PPARγ and Leptin in acute myelogenous leukemia.

▲ up

▶ Development of Tumor Markers for Effective Treatment of Cancer

    The development of tumor markers as well as target molecules for treatment of cancer is on-going using bioinformatics with SNPs and DNA chip. This study is performed using cancer cell lines as well as tissue samples or cells from cancer.

▶ Novel synthetic histone deacetylase inhibitors against leukemia cell lines

    Despite improvements in anticancer chemotherapy, appreciable number of patients succumb to disease due to emergence of resistant clones. Therefore, novel therapies are required to overcome drug resistance. Histone deacetylase(HDAC) inhibitors are emerging as a new class of anticancer agents with novel mechanisms. Since most HDAC inhibitors have the drawbacks of instability and low bioavailability, there is a great demand to develop more potent and less toxic selective HDAC inhibitor derivatives. We have tested new histone deacetylase inhibitors either alone or in combination with other well-known agents such as imatinib mesylate or other chemotherapeutic agents. Some of them showed remarkable anticancer activity, either alone or in combination therapy. We are focusing on the genes changed by HDAC inhibitors by DNA chip analysis.

▲ up

▶ Selection of new proapoptotic agents among natural biologic materials

    Curcumin, a natural, biologically active compound extracted from rhizomes of Curcuma species, has been shown to possess potent anti-inflammatory, anti-tumor and anti-oxidative properties. We investigated whether this agent decreases the proliferative potential and induces apoptosis of cancer cells. We found that curcumin caused dose-dependent apoptosis of chronic myeloid leukemia cell line, K562. By DNA chip analysis, we confirmed that apoptosis related genes were up-regulated and cyclin D1, cyclin A and several other genes were down-regulated. We suggest that their down-regulation by combined treatment was effective mainly via the induction of apoptosis. Taken together, our data suggested that combined treatment with curcumin could be effective to overcome the problems of resistance to well-known anticancer agents.      

▲ up

▶ uPAR/integrin shRNA in vivo model
(RNA Interference-directed Knockdown of Urokinase Plasminogen Activator Receptor Inhibits MMPs expression via dephosphorylation of Erk1/2 and Stat3 in AML)

    Plasminogen activation is implicated in solid tumor growth, invasion and metatastic spread. Extracellular proteolytic enzymes of the urokinase-type plasminogen activator (uPA) and metalloproteinase (MMP) family play a crucial role in the matrix degradation and tissue remodeling process characteristic of malignant disorders. The receptor for urokinase plasminogen activator (uPAR) serves to localize and intensify the action of uPA and is expressed on the surface of malignant cells. However, little is known about its role in leukemia. Since uPA and uPAR expression correlates with the progression of leukemia, therapies designed to inhibit uPA and uPAR expression would be beneficial. We utilized small hairpin RNAs (shRNAs), also referred to as small interfering RNAs, to target human uPAR. These small interfering RNA constructs significantly inhibited uPAR expression at both the mRNA and protein levels in myeloid leukemia cell line, HEL. uPAR knockdown in HEL cells resulted in a dramatic reduction of MMPs expression (MMP-2,-9, MT-MMP-1) and tumor cell invasion as indicated by a Matrigel invasion assay. Furthermore, RNA interference for uPAR abrogated uPA-uPAR signaling to downstream target molecules such as JAK2, JNK, ERK1/2 and Stat-3. These findings uncovered evidence of a complex signaling network operating downstream of uPA-uPAR that actively contributes to leukemia progression. Thus, RNA interference-directed targeting of uPAR is a convenient and novel tool for studying the biological role of the uPAR system and suggests the potential of its application for anti-leukemia therapy.

▲ up

▶ Identification of prognostic marker for Chronic Myeloid Leukemia
(FLT3, CD32, PU.1, ERG, uPAR, and TAP2 are strongly associated with the progression of chronic myeloid leukemia and combination of small interference RNA of TAP2 and STI571 synergistically induced the apoptosis in K562 cells)

    To characterize molecular mechanisms by which transition from chronic phase to blast crisis in chronic myeloid leukemia (CML) for developing novel therapeutic targets, we analyzed gene-expression profiles of leukemic cells from 12 patients in chronic phase and 9 patients in blast crisis using a 8.7K cDNA chip. We identified 89 genes that were up-regulated as well as 54 genes that were down-regulated in blast crisis of CML. The expression profile included oncogenes, tumor suppression genes, and human genes encoding proteins involved in transcription, signal transduction, metabolism, cell growth, differentiation, apoptosis and immune functions. 18 genes were selected among the up-regulated group for analysis using real-time PCR. Real-time PCR data indicated that the expression of FLT3 (p < 0.001), CD32 (p < 0.001), ERG (p < 0.001), uPAR (p < 0.001), MAD (p < 0.001) and TAP2 (p < 0.001) showed statistically significant difference between chronic phase and blast crisis. For further analysis, we utilized small hairpin RNAs (shRNAs), also referred to as small interfering RNAs, to target human TAP2. These small interfering RNA constructs significantly inhibited TAP2 expression at mRNA and protein levels in K562 cells. After treating both the TAP2 knockdown cells with STI571 and their controls, MTT assay and the expression patterns of apoptosis related genes (PARP, caspase-3, Bax) were examined. MTT assay and caspase-3 activity assay showed that simultaneous silencing of the genes for TAP2 significantly reduced cell viability and ultimately facilitated the induction of apoptotic cell death by STI571. These findings uncovered evidence of a complex signaling network operating down-stream of MDR/TAP2 that actively contributes to tumor progression. Thus, RNA interference-directed targeting of TAP2 with STI571 suggests the potential of its application against chronic myeloid leukemia.

▲ up

    We have investigated the mechanism of resistance of leukemia cells to Ara-C using an cDNA microarray designed for the analysis of leukemia cells. We established Ara-C?resistant cells from the HEL (acute lymphoblastic leukemia) cell line and compared their gene-expression profile with that of wild-type cells. The adenosine deaminase (ADA) gene was highly up-regulated in Ara-C?resistant cells whereas equilibrative nucleoside transporter 1 (ENT1) was down-regulated. In CGH analysis, we found that Ara-C-resistant cells did amplify the regions in 9p and 12q. We performed retrovirus-mediated transfection analysis to investigate the role of candidate genes in Ara-C?resistant cells. It showed that ENT1-transfected Ara-C?resistant cells were sensitized with the treatment of Ara-C. These results indicated that the down-regulation of the ENT1 gene is expected to result in nucleotide deficiency in addition to blockage of Ara-C influx. In this study we identified up-regulation of ADA and down-regulation of ENT1 as the factors responsible for Ara-C resistance, and this knowledge may be used to devise a new combination that will overcome the resistance.

▲ up

    Since biologic behavior of cancer cell is dependent on the activity of kinase, many studies have focused on the identification of small molecules such as kinase inhibitors. It has been reported that phosphorylated Janus protein tyrosine kinase family acts as signal transducers in cancer cells. Phosphorylatd JAK activated the phosphorylation of STAT family resulting in enhancement of the transcription of certain genes related to cell proliferation. Therefore, an inhibitor, which blocks the JAK/STAT signalling pathway, may become a potential candidate as anti-cancer drugs. In our previous study, we found three small molecules blocking the JAK/STAT signal pathway. We investigated whether three small molecules affect the cell proliferation in AML animal model and verified the mechanisms of suppression of AML progression. After verifying its mechanism, we examined whether these inhibitors are useful as anti-cancer drugs. Also, derivatives of candidate drugs will be tested to suppress AML progression. For our purpose, experiments will be performed as follows:
 1) Verification of growth inhibition of AML cells by small molecules such as
     JAK/STAT inhibitor.
 2) Verification of growth inhibition of AML cells obtained from AML patients
     by small molecules such as JAK/STAT inhibitor.
 3) Verification of effects of small molecules on the growth of AML cells in
     AML animal model.
 4) Development of derivatives of small molecules, which are more effective
     on growth inhibition of AML cells.

▲ up

    Our laboratory is located on the 3rd floor of Samsung Cancer Research Building (cri.snu.ac.kr) in the Yeon Geon Medical Campus of Seoul National University (medicine.snu.ac.kr), and on the 1st floor of Han Yang University College of Medicine. The official website of our laboratory is www.hematology-snu.or.kr, which is updated regularly.

▲ up

Ju Won Park
Graduate student
Te l : 82 2 3668 7078
Fax : 82 2 3668 7090
E mail : iymangel@empal.com

▲ up

Jae-Goo Seol, Ph.D.
MGenbio, Inc. (Managing Development Director)
#1101, World Meridian Venture Center, 60-24,
Gasan-dong, Guemchun-gu, Seoul, Korea
Jeonbuk 561-180, Korea.
Tel : 82 02 2113 7133  //  Fax : 82 02 2113 7139
Email : seoljg@mgenbio.com, seoljg@hotmail.com

Woo Hyun Park Ph.D.
Assistant Professor
Department of Physiology(Room 206)
Chonbuk National University Medical School
San 2-20 Geumam-dong, Deokjin-gu, Jeonju
Jeonbuk 561-180, Korea.
Tel : 82 063 270 3079   //  Cell : 82 010 9654 6103
Fax : 82 063 274 9892
Email : parkwh71@chonbuk.ac.kr

Jung Mi Hyun
Choongwae Pharma Corperation
146-141 Annyong-ri, Taean-eup, Hwasung-city, Kyunggi-do 445-976
Cell : 010 4879 3216
Email : jmhann@hanmail.net

▲ up

WH Park, ES Kim, CW Jung, BK Kim, YY Lee. Monensin-mediated growth inhibition in SNU-C1 colon cancer cells via cell cycle arrest and apoptosis. International Journal of Oncology, 22: 377-382, 2003

WH Park, ES Kim, BK Kim, YY Lee. Monensin-mediated growth inhibition in NCI-H929 myeloma cells via cell cycle arrest and apoptosis. International Journal of Oncology, 23:197-204, 2003

HS Lee, MY Jang, JH Choi, YY Lee, HB Park, YS Lee, SW Kim, MJ Ahn. Proliferation, apoptosis, and telomerase activity in human cord blood CD34+ cells cultured with combinations of various cytokines. Journal of Microbiology and Biotechnology, 13(3):422-428, 2003

MJ Ahn, JH Choi, YY Lee, IY Choi, IS Kim, SS Yoon, SY Park, BK Kim, C Suh, HJ Son, CW Jung, JH Lee, JM Sung, SA Im, D Oh, SY Jung, HJ Yoon, KS Cho, JA Lee, YJ Yuh, SR Kim, M Ki. Outcome of adult severe or very severe aplastic anemia treated with immunosuppressive therapy compared with bone marrow transplantation: multicenter trial. International Journal of Hematology. 78: 133-138, 2003

KW Lee, SB Chon, DY. Kim, T.Yun, SS Yoon, S. Park, BK Kim, NK Kim. Adrenal cortical carcinoma initially presented with overwhelming disseminated intravascular coagulation. Ann Hematol. 82:596-598, 2003

KW Lee, DY Kim, T. Yun, DW Kim, TY Kim, SS Yoon, DS Heo, YJ Bang, S. Park, BK Kim, NK Kim. Doxorubicine-Based chemotherapy for diffuse large B-cell lymphoma in early patients. Cnacer. 98:2651-2656, 2003

SH Kim, CI Kang, HB Kim, SS Yoon, MD Oh, EC Kim, SY Park, BK Kim, KW Choe Outcomes of Hickman Catheter salvage in Febrile Neutropenic Cancer Patients with Staphylococcus aureus Bacteremia. Infection Control and Hospital Epidermilogy. 24(12):891-904, 2003

Lee DS, Lee YS, Yun YS, Kim YR, Jeong SS, Lee YK, She CJ, Yoon SS, Shin HR, Kim Y, Cho HI. A study on the incidence of ABL gene deletion on derivative chromosome 9 in chronic myelogenous leukemia by interphase fluorescence in situ hybridization and its association with disease progression. Genes Chromosomes Cancer. 37(3):291-9, 2003

Song SU, Shin S-H, Kim S-K, Choi G-S, Kim W-C, Lee M-H, Kim S-J, Kim I. Effective transduction of osteogenic sarcoma cells by a baculovirus vector J General Virology. 84:697-703, 2003

Kim I, Yoon SS, Park S, Kim BK, Kim NK. The treatment of severe aplastic anemia: Outcomes of bone marrow transplantation and immunosuppressive therapy in a single institution of Korea J Korean Med Sci. 18:365-71, 2003

KW Lee, IS Choi, EY Roh, DY Kim, T. Yun, DS Lee, SS Yoon, S. Park, BK Kim, NK Kim. Adult patients with t(8;21) acute myeloid leukemia had no superior treatment outcome to those without t(8;21):a single institution’s experience. Ann Hematol. 83:218-224, 2004

CW Jung, JH Kwon, JG Seol, WH Park, JM Hyun, ES Kim, ST KIm, BK Kim, YY Lee. Induction of cytotoxic T lymphocytes by dendritic cells pulsed with murine leukemic cell  RNA. American Journal of Hematology. 75(3)L 121-127, 2004

KW Lee, JY Tak, T. Yun, DY Kim, DS Lee, SS Park, HI Cho, SS Yoon, S. Park, BK Kim, NK Kim. Extramedullary relapse confirmed by Fluorescence in situ hybridization study of an Ear Mass in Acute Promyelocytic Leukemia. International J. of Hematology. 79:462-464, 2004

SM Bang, SR Park, SH Park, EK Cho, SS Yoon, DB Shin, JH Lee, S. Park, BK Kim, NK Kim. Clinical features of Waldenstrom Macroglobulinemia in Korea. The Korean J. of Internal medicine. 19(3):137-140, 2004

Han SS, Kim K, Hahm ER, Lee SJ, Surh YJ, Park HK, Kim WS, Jung CW, Lee MH, Park K, Yang JH, Yoon SS, Riordan NH, Riordan HD, Kimler BF, Park CH, Lee JH, Park S. L-ascorbic acid represses constitutive activation of NF-kappaB and COX-2 expression in human acute myeloid leukemia, HL-60. L-ascorbic acid represses constitutive activation of NF-kappaB and COX-2 expression in human acute myeloid leukemia, HL-60. J Cell Biochem. 93(2):257-70, 2004

Suh C, Kim HJ, Kim SH, Kim S, Lee SJ, Lee YS, Kim EK, Kim SB, Lee JS, Kim MW, Kim K, Yoon SS. Low-dose lenograstim to enhance engraftment after autologous stem cell transplantation: a prospective randomized evaluation of two different fixed doses. Transfusion. 44(4):533-8, 2004

CI Joung, TY Kang, YW Park, WS Lee, YY Lee, MH Park, KB Joo, DH Yoo. Muscular  amyloidoma presenting presenting as inguinal masses in multiple myeloma. Scandinavian Journal of Rheumatology. 34: 152-164, 2005

JY Kim, SJ Oh, HK Park, JS Yoon, ES Kim, ES Kim, CS Kim, YY Lee, BK Kim.  Radioprotective effects of various cytokines in peripheral blood mononuclear cells and C3H  mice. Oncology Reports. 13: 1177-1183, 2005  

KW Lee, T. Yun, EK Song, II Na, H. Shin, SM Bang, JH Lee, ST Lee, JH Kim, SS Yoon, JS Lee, S. Park, BK Kim, NK Kim. Apilot study of Bortezomib in Korean Patients with Relapsed or Refractory Myeloma. J. Korean Med Sci. 20:598-602, 2005

JW Hur, YY Lee, WS Lee, JB Jun. Erythromelalgia as a presenting manifestation in a patient with essential thrombocythemia complicating renovascular hypertension due to unilateral renal artery stenosis. Rheumatology International. 26:83-85, 2005

JS Kim, J Kim, BS Kim, HY Chung, YY Lee, CS Park, YS Lee, YH Lee, IY Chung. Identification and functional characterization of an alternative splice variant within fourth exon of human nanog. Experimental and Molecular Medicine. 37(6): 601-607, 2005

YR Kim, HI Cho, SS Yoon, S. Park, BK Kim, YK Lee, H. Chun, HC Kim, DS Lee. Interpretation of Submicroscopic deletions of the BCR or ABL gene should not depend on Extr Single-FISH:Genes, Chromosomes & Cancer.  43:37-44, 2005

Park J, Kim S, Oh C, Yoon SS, Lee D, Kim Y. Differential tyrosine phosphorylation of leukemic cells during apoptosis as a result of treatment with imatinib mesylate. Biochem Biophys Res Commun. 336(3):942-51, 2005

Yoo HJ, Yoon SS, Park S, Park WS, Kim DJ, Lee EB, Song YW. Production and characterization of monoclonal antibodies to mesenchymal stem cells derived from human bone marrow. Hybridoma(Larchmt). 24(2):92-7, 2005

Han SS, Kim K, Hahm ER, Park CH, Kimler BF, Lee SJ, Lee SH, Kim WS, Jung CW, Park K, Kim J, Yoon SS, Lee JH, Park S. Arsenic trioxide represses constitutive activation of NF-kappaB and COX-2 expression in human acute myeloid leukemia, HL-60. J Cell Biochem. 94(4):695-707, 2005

Kim I, Yoon SS, Lee KH, Kim B, Kim TM, Kim JS, Kim HG, Oh MD, Han KS, Park MH, Park S, Kim BK. Comparative Outcomes of Reduced Intensity and Myeloablative Allogeneic Hematopoietic Stem Cell Transplantation in Patients under 50 with Hematologic Malignancies Clin Transplantation 2006, in printing

▲ up

0501843 A novel vitamin D3 analog with antitumor effect 2005-07-07

▲ up