본 연구는 topoisomerase inhibitors가 배양 각막 상피세포에서 세포고사를 유도하 는지를 조사기 위해 시행하였다. Topoisomerase inhibitors'{l camptothecin과 etoposide 를 제조사의 추천농도로 1-2 일 동안 배양하여 MTT assay를 이용하여 세포독성을 검 정하여 농도틀 정하고 세포고사를 확인하였다 세포고사의 형태적인 특징은 Hoechst 33342 staining, Annexin V - FITC/PI staining, DePsipher assay and CytoDEA TH staining을 이용하여 확인하였고 DNA fragmentation은 TUNEL파 agarose gel 전기 영동으로 확인하였다. Camptothecin 과 etoposide는 농도 의존성으로 세포고사룹 유또 하였는데 각막상피세포에서는 저l 조사의 추천농도보다 낮은 농도에서 세포고사플 유 도하여 다른 세포보다 민감한 것으로 나타났다- 이러한 결파로 볼 때 topOlsomerase l띠1ibitor는 각막상피세포에서 홀륭한 양성 대조군으로 활용될 수 있을 것으로 사료된다.

The present study was conducted to investigate gelatinolytic activities in HAM and to determine whether there are any changes in gelatinolytic activity profiles when the cells are cultured in hepatogenic medium. Placenta was obtained during caesarean section of the volunteers, with informed consent. HAM were isolated from amniotic membrane using collagenase type A HAM were cultured in hepatogenic medium for 3 weeks and the conditioned media were obtained at day 7, 14 and 21. The zymographic pattern of gelatinolytic activity of the HAM did not undergo a change during passages. When the HAM were cultured in a fibronectin-coated dishes in a hepatogenic medium, there was no significant difference of the gelatinase pattern between before and after culture. However, when bFGF was added to the culture, a dramatic increase of 62kDa and 59kDa gelatinases was observed. Interestingly, when ITS instead of FN was present, HAM-conditioned medium also showed a similar increase of both gelatinases. Immunoblotting analysis demonstrated that both 62kDa and 59kDa gelatinases were the active form of MMP-2 resulting from the turnover of MMP-2 proform. Futher study will be necessary to determine the relationship between bFGF and active MMP-2 during hepatogenesis of HAM.

This study was conducted to test whether the transgenic cattle pass the transgene to their progeny through germ cells, and whether the transgene is expressed in the mammary gland of ransgenic cows. Two male ransgenic calves were born from IVF-derived embryos injected with bovine β-casein/human lactoferrin fusion gene and then grew up to be reproducible. Semen was collected from a transgenic bull after 18 mon of age and then frozen. Bovine oocytes matured in vitro were fertilized with spermatozoa of the transgenic bull and cultured in 50㎕ drops of CRlaa medium supplemented with 3 mg/mL BSA. After 48 h of culture, cleaved embryos were determined for the presence of transgenes by DNA polymerase chain reaction (PCR). Proportion of transgene positives among bovine embryos fertilized with sperm of the transgenic bull was 20.9% (28/134). One of transgenic bulls did not produce transgenic sperm. Out of 34 calves produced from recipient heifers inseminated with semen of the other bull, 3 (8.8%) were transgenic animals (2 females and 1 male). Thus, one transgenic bull showed a low transmission frequency below Mendelian levels in both the IVF-derived embryos and his progeny. It was demonstrated by Southern blot that copy numbers of the transgene in the transgenic progeny enhanced about 1.8 times as compared to those of the founder bull The results demonstrate that the transgenic bull carrying human lactoferrin gene could pass his transgene to the progeny through germ cells, although he is a germ-line mosaic.

The purpose 01' pl'esent study was to examine the molecular events in apoptosis by CoCl2, mimicking hypoxic cond ition and recovering effects by LED ir l'adiation on Human SH-SY5Y neuroblastoma cells The SOUl'ce 0 1' light for ir l'adiation was a continuous-wave LED emitting at a wavelenl양h of 590 nm, and manufactured that ene rgy density was 5 mW!cm2 on sample surface, After ir l'adiation, cell viabi lity was measured with BrdU , cell morphol ogy was examined with Diff- Quik staining, cell signaling was monitored with various apoptosis-related molecules using RNase Pl'otection Assay(RPA) , W11en treated with CoC12, apoptotic induction was found in the SH-SY5Y cells in a concentration-dependent and time-dependent manner , Diff-Quik s taining was revealed that DNA fragmentation re presented apoptosis was examined in CoC12-tl'eated group, Moreover, RPA assay of SH-SY5Y cclls lIs ing val'iolls apoptosis-related molecllles showed that the apoptotic cell population was mcreased J-loweve. there was sorne signifïcant change in LED irradiatied cells aftel' treatement of CoC12 The main mechanism for Lhese a poptosis appearecl to be mito c hondriεt - m ecliated pathway, such as cytochrome- c‘ caspase-9, caspase-3, pro-apototic protein ßax, anti-apototic protein Bcl-2, and death receptor• mediated pathway, such as Fas, cas pase- 8, a ncl TNFRl These results demonstrate that CoCI2 induce apoptosis in SH-SY5Y via different dual apop tosis pathway through death receptor pathway as well as mitochondria- dependent pathway and LED irradiation can recl llces the CoCl2-induced apoptosis by blocking their internal signaling pathway

This study was to taken to demonstrate the effects of exogenous nitric oxide(NO) on hu rnan pu lp cell s ‘ In volvement of cyclic 3’, 5' -monophosphate(cGMP) in p버 paJ protection induced by herne oxygenase-l (J-lO-l) against NO-induced cytotoxicity , By use of Western blotting and cell viabi lity assay, we have examined the cytotoxicity and J-lO-l induction in pulp cells that were treated with NO donor ‘ S-nitroso-N-acetyl-D, L-penici 1 lamine(SNAP) , We have assessed wheathel' HQ--l contributes the cytoprotective effect against the cytotoxicity caused by NO, and inves tigated the l'elationship between HO-l and cGMP in the s ignaling pathway, SNAP decreased cell via bility but in creased HO-l expl'ession in a concentl'ation- and time一dependent manner in hurnan pu lp cells NO-induced cyto toxicity was inhibited in the presence of the hemin(inducer of HO-l) , whel'eas was en hanced in the pl'esence zinc protoporphyrin IX(ZnPP IX, HO-l inhibitor), thus Lhe NO-induced cytoLoxicity was cOl'related with HO- l expression. R‘ etreatment with a rnemhrane-permeable cGMP analog, 8-bromo-cGMP, restored cell death and enhanced the HO-l protein expression induced by SNAP, ln contrast‘ inhibition of guanylate cyclase by lI-l -[1,2,4] ox adiazole[ 4,3 口]quinoxalin-l-one(ODQ) pretreated pulp cells to 1 mM SNAP resulting in marked cytotoxicity , These findings , demonstrating a link between J-lO-l, regulated thl'ough the cGMP system and NO-induced cytotox.icity in huma띠 p버 p ceJls , suggesti ng a protective 1'ole of HO-l in pulp infl ammatory disease

rt is well known that glycosaminoglycans are 01' fllndamental importance to the processes 01' morphogenesis and cytodifferentiati on dllring the teeth development , With HlD-TCH-SP(High - iron diamine-thiocarbohydrazide-silvel protcinntc) , s lllfatcd glycosaminoglycans such as chondroitin sulfate and heparan slllfate have been localized a t the III trastrllctural level i n a wide variety of tlssues The pmpose of this stlldy were to examine slllfated glycosaminoglycan at llltrastrllctllral level fo 1' the phase of morphogenesis and cytodifferentiation of hllma n fetal tooth germs, and to detect the protein expression of slllfated glycosaminoglycan by immunoslot blot Human tooth gerll1s fl'Oll1 the a lveolar bone of twenty still born fetuses we1'e fixed in a mixtllre of 2% gllltaraldehyde/1% forma ldehyde, The 미 t 1'athin sections were stained witb HID-TCH-SP and were treated with 0, 05% solution of t esticular hyaluronidase to identify the histochemical properties 01' tbe HID-TCH-SP stain deposits , For semi quantitative protein assay , immllnoslot blot was done Sulfated glycocongugated deposits were localized in DEJ, peri tubular dentin , and mantle dentin matrix‘ enamel prism sheath , interrod area , and enamel matnx Heparan sll l띠 te deposits i n DEJ resisted to testicular hyalllronidase treatment prior to HID-TCH-SP staining, Immunoslot blot s howed that• chondroitin sulfate was detected higher in enamel and dentin extract, while heparan sulfate was relatively expressed in enamel and dentin extract, but rarely expressed in enamel or dentin extract It suggest ecl that chonclroi tin and hepa ran slllfate woulcl play an important role in the formation of DEJ, while chondroitin sulfate would in the clevelopll1ent of enamel prism sheath, enamel matrix, and mantle 01' peritublllar clentin of human fetal tooth germs,

Gene reg비 at i o n during the human craniofacial development is not well understood In effort to understand n ewly identifï ed genes that may play role(s) in the human craniofacial development, non-redundan t genes were isolated from the s ubtracted cDNA libra ry of human embryonal craniofacial tissues and examined their possible structu ral rolc in parallcl with thosc gcncs from isolatecl human c h o nclroc)πes cDNA library. Fifty genes were init ia ll y chosen from 398 clones iso latecl were used for selective dominant expression in both chondrocytes and the craniofacial sections of 10 weeks old human embryo by in situ hybridization method. Based upon the high levels 。f expression, we have identifi ecl seven unknown genes; ch89, ch96. ch129. ch 153. ch 276 ch285. and ch334 . In 。rder to unde rs tancl the possi ble role of these genes‘ the structural simulation of the expressed proteins were constructecl by Sybyl 6.6 program. Ch 276 gene was same with a clone, c14 0 1' f173. registered in GenBank(NM_022489) a nd is composed 0 1' 323 amino acids having a reverse s ignaling domain from the extra- cellular matrix(C-terminal) to cell membrane(N-terminal) and 12 turns of helical structure. Gene protein also r etains a famil iar fïbronectin binding domain(RGD). three s ites 0 1' Ca ion binding motifs. cAMP- and cGMP-dep endent protein kinase phos phorylation site, two regions of protein kinase C phosphorylation s ites. glyco- saminoglycan attachment s ite ancl N-glycosylation site. transmembrane and Al kaline Phosphatase active s ite domains This newly iclentifï ed human protein from human choncl rocytes cDNA library appearecl to be related to a known calcification s ignaling protein. was named as Ca lsin(Ch276) . Ch153 appeared to be related a family of anti-microbial peptide acting as an inflammation mediator and Ch334 clone as a zinc finger protein whose expression in creases in human adult ti ssue‘ These results suggest that these novel genes ident i!ï ed from human chondrocytes rnay provide a new path 0 1' embryonic cartilage development and human craniofacial development.

Cellular imrnortali zation is thought to be an ear ly event during tumorigenesis. Telomerase reacLi vaLion by ecLopic hTERT expression is widely used for cellular imrnortali zation. This study was a imed Lo a na lyze establi sh immortalized human ora l epithelial cells(IOEC) and to reconstruct oral precancerous lesion by Lhree dimens iona l cultures. Telomerase activity was analyzed by Telomerase assays and Telomere longLh W:lS dcLccLcd by Termina l restri ction I"ragment analysis. bTERT gene was assayecl by tbe RT-PCR. p16lNK4 a‘ pHb. CDK2. P21CIP1. p27 and p53 were examined by western blotting. Three dimensiona l cu1ture using air - liquicl inLe rl"ace was pe rl"ormed. As results. IOEC was establi shed by ectopic ex pression of catalytic subunit• of telomerase‘ h1'EH1'. which is con tinuously maintained for more tban 120 population doublings(PDs) . IOEC showecl the expression 01" h1'ER1' and h1'H mHNA‘ elongated telomere length and higher telomerase activity. These cel ls showed no ex pression of p16lNK4a with retention 01" pRb and CDK2. Expression of p21CIP1. p27 a nd p53 may have no relation to immorta li ze oraJ epithelial cell s. Three dimensional culture of IOEC showed dysplastic strat ilïed epithelia l cell s. These results may serve as a useful moclel system for the study of oral carcinogenesis.

1'0 determine Lhe ll1echanism of cell c1eath incluced by iron chelators. we explored the pathways of the three structurally relatecl ll1 itogen-activatecl protein(MAP) kinase subfami li esduring iron cbelator- inclucecl apoptosis ancl differentiation of oral precancerous ancl cancel‘ cells. The iron chelator c1 eferoxamine(DFO) exertecl potent timeancl c1ose-c1epenclent inhi bitory effects on the growth of IHOK and HN4 cells The major mechanism of growth inhibition following DFO treatment was fOllncl to be apoptosis incluction. as assessecl by annexin V-FITC staining. cell cycle analysis‘ DNA lacldering, a ncl Hoechst staining. We report that DF'O s trongly activates the p38 MAP kinase and extracell ular signal- regu lated kinase(ERK). but c10es not activate the c-Jun N-terminal kin ase/ stl않s-activaLecl protein kinase(JNK/8APK) . Of the three MAP kinase blockers usecl‘ the selective p38 MAP kinase inhibitor 8ß203580 ancl ERK inhibitor PD98059 protected oral premaIignant ancl malignant cells againsL iron chelator- nclllced cell death. which incl icates that the p38 MAP kinase serves as a major mecliator 01' apoptos is induced by this iron chelator DFO also evoked the release of cytochrome c from mitochondria, and incluced the activation of caspase-3 ancl caspase-8 in oral cancer cells, which suggests that apoptosis occurs via the mi tochoncl ri on - mecl iaLed pathway. DFO enhanced the expression of Bax in IHOK ancl HN4 cells. consistent witll thei r p53 status Moreover. DFO downregulatecl the expression 01' Bcl-2 in oral cancer cells. which suggests that DFO- incluced apoptos is 01' oraJ cancer and precancerous cells may be mediatecl by an increase in the ratio of pro-apoptotic to anti-apoptotic proteins. ln terestingJy, trcatmcnt 01' IHOK ancl HN4 cel ls with 8B203580 abolishecl cytochrome c release‘ as wel l as the activation of caspase-3 and caspase-8. DFO suppressecl the expression of epithelial di ffe rentiation markers, such as involucrin, t ransglutaminase II. CK6. and CK19. ancl this suppression was blockecl by p38 ancl ERK MAP kinase ll1hlbltors The oral premalignant(IHOK) ancl malignant cell s(I-lN4) showed differential responses to DFO with respect to the expression of cel l cycle regulatory proteins. cell growth. ancl apoptosis. Coll ectively. the current study reveals that p38 MAP kinase plays an ill1 portant role in iron chela tor-mecliatecl cel l cleath and in the suppression of differentiation of oral premalignantandmalignanLcell s.by activating a c10wnstream apoptotic cascade that executes the ceIl c1eath pathway

Interlellkin • 8(IL-8) is an important cytokine involved in tllmor growth and angiogenesis in a variety of malig nancies. bllt the regll lation of IL-8 in 01 외 cancer cells are llnderstood . We invesLigated whether mi togen-activated protein kinases pathway is involved in iron chelator-mediated lL-8 produdion in inunortalized and malignant oral keratinocytes. In this study we examined the role of p38 and extracellular signal- reglllated kinase• 1/2 in the expression of [L-8 by DFO. Incllbation of IHOK and HN12 cel ls with DF'O increased the expression of 11-8 mRNA. as well as the release of IL-8 protein. The signal transdllction study revealed that both p38 and ERK1/2 were significantly activated in response to DFO. Accord ingly. the selective inhibitors for both kinases‘ eit her a lone or combination. abolished DFO- induced lL-8 secretion. indicating an importance of MAP kinase pathway. Interestingly. however‘ inhibition of the p38 and ERK pathway more attenuated IL-8 secretion in IHOK than in HN12 cells. DFO induced NF-kB activation , suggesting a NF-kB- dependent mechanism in DFO- induced IL-8 production. In addition, p38 and ERK inhi bition resulted in the accelerated degradation of lL-8 mRNA, suggesting that in IHOK and HN12 cells, p38 and ERK cunLr iullLe Lo DFO imluced IL-8 secretion by IHOK and HN12 cells via a posttranscriptional mechanism that involves stabilization 01' the IL-8 transcript. Finally. we investigatecl llsing specific inhibitors : 8NP and G8NO for NO c1onor. PDTC for potent inhibitor of NF-kB. Cycloheximide for inhibition of de novo protein synthesis. We observecl 8NP ancl PD1'C clepenclent IL-8 gene incluction in IHOK cell s. but not in HN12 cells used specific inhibitors‘ Collectively. these results demonstrate that‘ targeting MAP kinase ancl NF-kB pathway may be a potentiaI approacb to controlling the angiogenes is ancl growth 이 human oral cancers

Since oral keratinocytes represent the natmal target for HPV(human papill omavi ruses) infecti on, HPV infection may be involved il1 the developmel1t of oral SCC. Through compaJ'ing the morph이 ogic featw-es of NHOK to 다fOK accorcling to calcium concentration by TEM, immortali zed oral keratinocytes(IHOK) transfected by E6/E7 gene of HPV 16 have been gained wide acceptance as a model system for HPV-linkecl oral carcinogenesis. The purpose of this study were to exami ned the ultrastructural fcaturcs of culturcd NHOK, IHOK, and HN4 oral squamous cell CaJ‘CI noma celJ line, and to apply these results to oral carcinogenesis in the future, Prima:rily cul tlU'ed NHOK, IHOK ++ and HN 4 cell line which were cu ltu red under 015 and 12mM CaTT of 1ιBM bulJet kit For tra nsmission electronmi crosco py(TEM). under preconfluency‘ and after 3 days of postconfluency uncler 1.2mM Ca ++‘ cultured NHOK IHOK, and HN4 cell line were immediately fixed in 2, 0% gluta:raldehyde in O.lM cacodylate buffer(pH 7, 4) at 40C 1'01' 1h TEM of cultured NHOK under 1. 2mM Ca ++ showed increased tonofi laments‘ and vaculated ovoid cells wi th cornifi ed envelope, whi le cultured IHOK showed prominent microvilli , unilateral desmosome in microvillus‘ and tonof t!amen ts Under high calcium cu ltured IHOK showed less tonofilaments than that of cultured NHOK, while cu ltu red lHOK a nd HN 4 cell lines showed more increased desmosomes under high calclUm It suggested that the ultrast ru ctura l cha nges of cultured IHOK would be accepted as the morphologic changes of intermediate stage aJl10ng oral carci nogenesis ,

It is well kwon that HPV have been strongly linked to progression of or al squamous cell carcinoma‘ Effici ent im mortalization of nonnal human oral keratinocyte(NHOK) should provid further evidence for the role HPV in tumorogenes is ‘ Because IHOK(I mmortali zed human oral keratinocyte) has been considered as a moclel syst em for study ing I-!PV- linkecl oral ca rcinogenes is , it is important to pursue the differenti ati al change of IHOK cul t ure moclel during t he culture passage, The purposes of this study were to examine the cha ra r’ ct eristic clifferential changes of cul turecl immorta lizecl human ora l keratinocytes during long term passage, and to apply these results to or al carcinogenes is in the future, NI-!OK was primarily incubated at 370C and 5% C02 under KBM bullet kJt IHOK was co ntinuously cul t ured towarcl 100th passage(two times per week) , Growth curve of NI-!OK and II-!OK clepend on clùture passage was taken For examining the cha racte ri s t ic clifferential changes of II-!OK, transrnission electron microscope, 1ì'ansgluta miase activity‘ E6/E7 mRNA detect ion, a ncl tumorogenecity were done 10th II-!OK showecl sl ight polygonal flattencl cells and sometimes apoptotic cells ‘ while 100th IHOK showecl increased polygonal cell s ‘ Cultu recl 100th IHOK showed r ela tively resis tant growth to high calcium than 10th II-!OK Microvilli from 10th II-!OK was not connect ecl with each other, ancl scatte red cytokeratin fil aments of 10th II-IOK. while decreased cytokeratin filaments in cytoplasm & prominent clesmosome of 100th IHOK. During the terminal differ entiation in cultured IHOK, induction of TGase 1 activity of 10th II-!OK was higher than that of100th IHOK mRNA E6E7 expresson was cletected and unchangable in both cul tured cells There was no tumorogenecity inclucecl by both culturecl cel ls. Although late passage IHOK showecl less r esemblance to NHOK, and lower TGase 1 acti vi ty than ea rly passage IHOK, it suggested that these cells should be 110t yet fully differ entiatecl to oral squ a mous ce ll carcinoma cells

Periodontitis is a chronic infectious disease that leads to the destruction, one of the major cause of tooth loss in human. Osteoclast Differentiation Factor(ODF), also called as Receptor activator of NF-xB ligand(RANKL), a surface-associated ligand on bone marrow stromal cells and osteoblasts, activates its cognate receptor RANK on osteoclast progenitor cells, which leads to differentiation of these mononucleated precursor cells. Osteoprotegerin(OPG), a decoy receptor, is released from stromal cells and osteoblasts to inhibit the interaction between RANKL and RANK. The experiment for the effect of pregnancy on gingival health showed greater gingival inflammation and edema during pregnancy, despite similar plaque index. There should be many factors affecting the periodontal health in pregnancy. In this experiment, we examined the direct effects of sex hormones(estrogen and progesterone) on the ODF/OPG expression in human gingival fibroblasts and periodontal ligament cells at the serum concentration of pregnancy. The ratio was high in the 1st trimester of pregnancy by estrogen and in the late 2nd trimester by progesterone. Therefore, the local periodontal destruction might be accelerated by these hormonal effect on the periodontal cells.