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Regulation
of gene expression,growth,and cell survival by IL-4:Contribution of multiple
signaling pathways
KEENGAN ACHSAH D,Jerome
H.Holland Laboratory,American Red Cross,Rockville,MD.USA
ABSTRACT
Interleukin-4 is a
cytokine produced by activated T cells,mast cells,and basophils that elicits
many important biological responses. These responses range from the regulation
of helper T cell differentiation and the production of Ig to the regulation of
the adhesive properties of endothelial cell via VCAM-1. In keeping with these
diverse biological effects,high-affinity binding sites for IL-4 have been
detected on many hematopoietic cell types at levels ranging from 50 to 5000
sites per cell. This review will
focus on the discreate signal transduction pathways activated by the IL-4
receptor and the coordination of these individual pathways in the regulation of
a final biologicaloutcome.
Key
words：Cytokines,receptors,lymphocytes,tyrosine
phosphorylation,signal transduction.
The
role of the hedgehog/patched signaling
pathway in epithelial stem cell proliferation:from fly to human
PARISI MICHAEL J,HAIFAN LIN
Department of Cell Biology,Box 3709,Duke University, Medical Center
Durham,N.C. 27710 USA
Emails: m.parisi@cellbio.duke.edu
The hedgeho-patched
(hh-ptc) intercellular signaling pathway has recently been shown to control
the proliferation of epithelial stem cells in both Drosophila and vertebrates.
Mutant and ectopic expression analyses in Drosophila sugguest that the HH
protein diffuse from the signaling cells to promate the proliferation of nearby
ovarian somatic stem cells by antagonizing of nearby ovarian somatic stem cells
by antagonizing the suppression of its receptor PTC towards the CI transcription
of CI-dependent genes leads to stem cell proliferation . This regulatory pathway
appears to function also in vertebrates ,where defects in ptc cause basal cell
carcinoma,tumors of epidermal stem cell origin. Basal cell carcinoma can also be
induced by ectopic expression of Sonic hedge hog(shh) or Gli1, the vertebrate
homolog of ci. These students suggest the conservation of the hh signaling
pathway in conservation of the hh signaling pathway in controlling epithelial
stem cell divisions among different organisms.
Key words: stem cell,epithelia,hedgehog,patched,Drosophila,vertebrate.
Types
of voltage-dependent calcium channels involved in high potassium
depolarization-induced amylase secretion in the exocrine pancreatic tumor cell
line AR42J
CUI Zong JIE
Beijing Agricultural University Faculty of Biological Sciences,Beijing
100094,China.
ABSTRACT
In the perifused fura-2
loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium
induced repetitive increases in intracellular calcium. Attached cells when
stimulated with high potassium secreted largeamount of amylase. High
potassium-induced secretion was depedent both on the concentration of potassium
and duration of stimulation .High potassium induced increases in intracellular
calcium were inhibited by voltage-dependent calcium channel antagonists with an
order of potency as follows: nifedipine >ω-conotoxin
GVIA. In contrast , the L-type calcium channel antagonist nifedipine almost
completely inhibited potassium-induced amylase secretion,whereas the N-type
channel antagonist ω-agatoxin IVA had a
small inhibitory effect, but this inhibition was not significant at the level of
amylase secretion . In conclusion, the AR4-2J cell line possesses different
voltage –dependent calcium channels(L,P,N) with the L-type predominantly
involved in depolarization induced amylase secretion.
Key word: AR4-2J,pancreatic acinar
cells,amylase,secretion,calcium channels.
Trichosanthin
inhibits T cell activation by interfering with the recruitment of zap-70 to CD3 ζchain
HONG JIAN,SAI LI FU,ZHONG YI,PEI HUA LU,KUANG YEN CHOU
Shanghai Institute of Immunology,Shanghai Second Medical
University,Shanghai China
ABSTRAT
Plant protein Trichosanthin(Tk) has been shown in our previous
experiments to suppress antigenic response of T cells. Here we explored its
inhibitory mechanisms on the proliferation of human Jurkat leukemia T cell
triggered by anti-CD-3 McAb.By examination of tyrosine phosphory-lation of cell
lysate,we were able to show that Tk could interfere with the PTK-related
activety in the TCR/CD3-initiated signal transduction in addition to blocking
the phosphorylation of PKC.As shown in our experiment, the expression intensity
of ZAP-70, a kind of protein tyrosine kinase,was not changed but its
phosphorylation could be inhibited. When physical link between CD3ζchain
and ZAP-70 was further examined by using co-immunoprecipitation after pluse-treatment
of the cell line with Tk, the anti-CD3 McAb-induced recruitment of ZAP-70 to CD3ζchain
was observed to be blocked in some extent. This may account for , at least in
part, how Trichosanthin was able to inhibit the TCR-triggered T cell
proliferation.
Key words : Trichosanthin;TCR-signaling; PTK; tyrosine
phosphorylation.
The
effect of external Ca2+ and
Ca2+ -channel modulators on red-light-induced swelling of protoplasts
of Phaseolus radiatus L
Department of Biology,South China Normal University,Guangzhou 510631,China
ABSTRACT
Red-light-induced swelling of the protoplasts isolated from hypocotyls
of etiolated mung bean(Phaseolus radiatus L) was observed only when Ca2+ ions
were present in the medium . The optimal CaCl2 concentration was 250 µM. Swelling response declined when Ca2+ was supplied into the medium after red light
irradiation. The Ca2+ chelator EGTA eliminated the red-light-induced
swelling and 45Ca2+ accumulation in the protoplasts. In
contrast, A23187 , a Ca2+ -ionophore,could mimic the
effect of red light in darkness. These results indicate that Ca2+ may
play a role in light signal transduction. In addition, swelling response was
prevented by TFP and CPZ(both are CaM antagonists), implying the involvement of
CaM in red-light-induced and Ca2+-dependent protoplast swelling.
Key wods: Calcium ions, red light , protoplast swelling, 45Ca2+
accumulation ,Phaseolus radiatus
Immunolcocalization
of actin in intact and DNA-and histone-depleted nuclei and chromosomes of allium
cepa
WAN LI HONG,MIAO XING
Institute of Genetics and Cytology,Northeast Normal University,Changchun
130024,China
ABSTRACT
The presence of
actin in eukaryotic and chromosomes ,and especially in higher plant nuclei and
chromosomes, has not been well established. We detected actin in meristematic
cells of Allium cepa with indirect immunoflu-orescence technique and observed
bright fluorescence in the intact nuclei and chromosomes,indicating that actin
is present in the nuclei and chromosomes of the higher plant . We labeled
sections of the meristematic cells of A. cepa with immunogold technique, gold
particles were found over he whole nuclei and a number of gold particles were
concentrated in condensed chromatin and nucleoli, conforming the results of the
immunofluoresence observations. We treated the nuclei and chromosomes of A.
Cepa withDNase I and 2M Nacl and obtained DNA-and
histone-depleted
nuclei and chromosomes reacted positively with the anti-actin antibodies.These
results demonstrate that actin exists not only in intact nuclei and chromosomes,
but also in DNA-and histone-depleted nuclei and chromosomes of the plant. In
addition, our immuno-fluorescence tests of the plant. In addition, our immuno-fluorescence
tests indicate that tropomyosin is
present in the nuclei and chromosomes of A.cepa
Key words: Actin,Allium cepa, chromosomes, nuclei
EGFR
antisense RNA blocks expression of the epidermal growth factor receptor and
partially reverse the malignantphenotype of human breast cancer MDA-MB-231 cells
FAN WEN HONG ,YING LIN LU,FAN DEBG,XUE MING GE,SHAUNG LIU,PEI-HESIN TANG
Institute of Basic Medical Science,Beijing 100850,China
ABSTRACT
The effects of human EGFR to the malignant phenol-type of human breast cancer cell line MDA-MB-231 were investigated experimentally. A retroviral vector containing a 5,1350bp fragment of the human EGFR cDNA in the antisense orientation was transfected into targeted cells by lipofectamine. The effects on cell proliferation,cell cycle and adherent ability to extracellular matrix(ECM) components were studied after the expression of antisense transcripts to EGFR 5,1350bp fragment in target cells . In vitro studies showed that the growth ability of the transfected cells was partially inhibited in comparison to parental cells and to cells transfected with the plasmid containing the neomycin resistance gene only. It was found that EGF(10ng/ml) had an augmentation effect on the growth of transfected MDA-AS10 cells but not MDA-MB-231 cells. Flow cytometric analysis showed that the cell cycle of the transfected cells was abnormal with a decrease of cells in G2/M and S phases and an increase of cells in G1 phase, indicating a blockage in phase G1. Immunofluorescence of EGFR expression in transfectants stained with an anti-EGFR antibody was decreased and their growth in soft agarose was also severely impaired. The transfected cells showed less adherence to laminin(LN) and fibronectin(FN). In short, EGFR antisense RNA decreases the expression of EGFR on MDA-MB-231cells and partially reverses theirs malignant phenotype as well.Effects of antisense EGFR on human breast cancer MDA-MB-231 cells
Key words: EGFR ,antisense
RNA,human breast cancer cells ,gene transfection.
The
use of suicide gene systems in vascular cells in vitro
XU LING FEI,DE HUA XU,KAI KAI CE,ZHONG CHENG ZHENG,LAN YIN SUN,XIN YUAN
LIU
Shanghai institute of Biochemistry,Chinese academy of Science Shanghai
200031,China
ABSTRACT
To investiagate the efficiency of suicide gene systems on vascular
cells,HSV-tk/GCV and EC-CD/5 FC systems were establish on vascular endothelial
cells in vitro by retroviral transduction. Both modified cell lines were highly
sensitive to prodrugs , the IC50 for GCV was less than 0.4 µM,
and IC50 for 5-FC was
less than 75 µM,while
the parental endothelial cells were insensitive even at the highest
concentractions of prodrugs in this experiment. Mixed cellular assay showed that
significant bystander effect was exhibited in modified endothelial cells . When
only 10% or 30% of the mixed cells were tk positive and exposed to 20 µM
GCV for 6 days, more than 60% or 90% of the whole population was killed .Similar
result was also found in CD positive cells . These results indicated that both
HSV-tk/GCV and EC-CD/5-FC systems could efficiently suppress endothelial cell
growth in vitro.
Key words: Endothelial cell, suicide gene, HSV-tk/GCV system,EC-CD/5-FC system, bystander effect.
The RAF family : an expanding network of post-translational controls and protein-protein interactions
YURYEV ANTON,LAWRENCE P WENNOGLE Novartis Pharmaceuticals
Corporation,Summit,NJ,USA
ABSTRACT
Protein
kinase RAF is strategically located in the “Ras-MAP-kinase signal transduction
pathway” , a principle system which transmits signals from growth factor
receptors to the nucles, resulting in cell proliferation.Growth factor response
are mediated in part by activation of Ras, which in turn activates RAF to
phosphorylate MEK, its downstream substrate. Mek activities MAP-kinase to
influence nucleat events. It is clear, however,that a network of signals other
than those carried by Rasplay a role in RAF network ,these orthogonal influences
are mediated by: serine/threonine kinases,tyrosine kinases, and protein
interactions. As a further complication to the RAF network , three isoforms of
RAF have been established which have divergent N-terminal regulatory domains.
Whereas these divergent regulatory domains implicate isoform-specific
functions,no clear evidence or hypothesis for distinct function for individual
isoforms has been presented.
Recently, “isoform-specific protein interactions” have been identified among
numerous protein interactions” have been identified among numerous proteins” have been identified among numerous proteins interacting with RAF.These studies
may serve to delineate independent function for RAF isoforms.
On
the history of nuclear matrix manifestation
ZBARSKY IB
N.K. Koltzov Institute of Development Biology,Russian
Academy of Science.26, Vavilou Street, 117334, Moscow, Russia.
Email: ibzba@ibrran.msk.su
ABSTRACT
The nonchromatin
proteinous residue of the cell nucleus was revealed in our laboratory as early
as in 1948 and then identified by light and electron microscopy as residual
nucleoli, intranuclear network and nuclear envelop before 1960. This structure
termed afterwards as “nuclear residue”, “nuclear skeleton”, “nuclear
cage”, “nuclear carcass” etc., was much later(in 1974) isolated, studied
and entitled as “nuclear matrix” by Berezney and Coffey, to whom the
discovery of this residual structure is often wronly ascribed. The real history
of nuclear matrix manifestation is reported in this paper.
Key words: Nuclear matrix,
nuclear residue, nuclear fraction, history of nuclear fractionation
STAT1
is involved in signal transduction in the EPO induced HEL cells
JIANG CHU, CHUANG YUN CUI, JIE FAN
XIAO DA TANG, RUO LAN QIAO
Shanghai Institute of Cell Biology, Chinese Academy of Sciences
,Shanghai 200031, China
Dept of Urology, Shanghai
First people’s Hospital,
Shanghai 200081, China
ABSTRACT
Erythropoietin(EPO)
is the major regulator of mammalian erythropoisis, which stimulates the growth
and differentiation of hematopoietic cells through interaction with its
receptor(EPO-R) . Here we use HEL cells ( a human erythro-leukemia cell line) as
a model to elucidate the pathway of signal transduction in the EPO-induced HEL
cells . Our data show that the EPRO (EPO receptor) on the surface of HEL cells
interacts with the Janus tyrosine protein kinase (Jak2) to transducer
intracellular signals through phosporylation of cytoplasmic proteins in EPO-treated
HEL cells. Both STAT1 and STAT5 in this cell line are tyrosine-phosphorylated
and translocated to nucleus following the binding of EPO to HEL cells.
Furthermore, the binding of both STAT1 and STAT5 proteins to specific DNA
elements (SIE and PIE elements) is revealed
in an EPO-dependent manner. Our data demonstrate that the pathway of
signal transduction following the binding of EPO to HEL cells is similar to
immature erythroid cell from the spleen of mice infected with anemia strain of
Friend wirus.
Key words: Erythropoietin,HEL
cells, signal transduction.
An
Arabidopsis embryonic lethal mutant with reduced expression of alanyl-tRNA
synthetase gene
SUN JIAN GE, XIAO LI YAO,ZHI XING YANG,ZHI PING ZHU
Department of Plant
Development. Shanghai Institute of Plant Physiology, Chinese Academy of Science,
Shanghai,China, 200032 Email: zhu@iris.sipp.ac.cn
ABSTRACT:
In present
paper , one of the T-DNA insertional embryonic lethal mutant of Arabidopsis is
identified and designated as acd mutant. The embryo development of this mutant
is arrested in globular stage. The cell division pattern is abnormal during
early enbryogenesis and results in disturbed cellular differentiation . Most of
mutant embryos are finally degenerated and aborted in globular stage. However, a
few of them still can germinate in agar plate and produce seedings with shorter
hypocotyls and distorted shoot meristem. To understand the molecular basis of
the phenotype of this mutant, the joint fragment of T-DNA/plant DNA is isolated
by plasmid rescue and Dig-labeled as probe for cDNA library screening .According
to the sequence(EMBL accession#Y12555 )from
Selected positive clone shows a 99.8% (923/925bp) sequence homology with
Alanyl-tRNA Synthetase(AlsRS) gene of Arabidopsis theliana. Furthermore, the
data of in situ hybirization experiment indicate that the expression of AlaRS
gene is weak in early enbryogenesis and declines of AlaRS gene is weak in early
embryogenesis and declines along with globular embryo “development” in this
mutant . Accordingly, the reduced expression of AlaRS gene may be closely
related to the morphological changes in early embryogenesis of this lethal
mutant
Key words: AlaRS gene embryonic mutant, Arabidopsis.
Isolation of 24 novel cDNA fragments from microdissected human
chromosome band
ZHANG MIN, LONG YU, PEI RONG HU , AN DING BI, JIA HUI
XIA, HAN XIANG
DENG, SHOU YUAN ZHAO
Institute of Genetics ,Fudan University , Shanghai 200433 China
State Key Laboratory of Medical Genetics, Hunan Medical University,
Changsha 410078 ,China
ABSTRACT
The
strategy of isolating the band-specific expression fragment form a probe pool
generated by human chromosome microdissection was reported. A chromosome 14q24.3
band-specific single copy DNA pool was constructed based on this probe to
hybridize the human marrow cDNA library , 68 primary positive clones were
selected from 5*105 cDNA clones. Among these primary clones, 32
secondary clones were obtained after after second-round screening and designed
as cFD14-1~32. Finally, 24 band-specific expression fragments were identified
from these 32 positive clones by DNA hybridization. Those band-specific clones
can hybridize to both 14q24.3 DNA and human genomic DNA but can’t hybtidize to
17q11~12 DNA. Partial sequences of 13 fragments of 13fragments of them were
sequenced and identified as novel cDNA sequence, and these sequences were proved
to have some homology with known genes in NCBI database. Analysis of expression
spectrum of cFD14-1 suggested that the cDNA fragments thus obtained should be
used to isolate the genes can not been cloned in 14q24.3 region.
Key
words: Probe pool , chromosome 14q24.3, single copy DNA pool , expression
sequences of genes.
Analysis
of the 5’flanking sequence of the human norepinephrine transporter gene
HUANG
FANG, JIAN FEI ,SHUN KAI MA, LI HUA ZHU, ZHAO PING LIU, GUO QIANG CAI, ZEN CAN
YE, LI HE GUO
Shanghai
Institute of Cell Biology, Chinese Academy of Science, Shanghai 200031, China
ABSTRACT
The
human norepinephrine transporter(NET) gene was cloned and structurally analyzed.
The far 5’ fragment containing . The transcription start site of the gene in
human brain stem tissue was determined by primer extension analysis . It was
found that the gene could be transcribed form multiple starting points . The
5’s flanking sequence contains a proximal G-C rich region, one possible GSG
element and several SP1 sites . Howeverm it does not contain TATA box motifs.
Gel shift analysis with nuclear extracts form different tissues of mouse shows
that the G-C rich may be involved in tissue specific expression of the gene.
Key
words: Norepine transporter gene, primer extenxion, transcription regulation.
The
studies on neurogenesis induced by brain injury in adult ring dove
ZUO
MING XUE
Biology
department, Beijing Normal University, Beijing 100875, China
Abstract
It
was the first time demonstrated by us that the number of newborn neurons was
increased after making lesion in forebrain of adult ring dove(Streptopelia
risoria) by means of adult avain is restricted to the telencephalon. In doves
with bilateral electrolytic lesion of nucleus ectostriatum(E) , the mean number
of proliferating cells in the lateral ventricular zone (LVZ) and newborn neurons
in the forebrain increased by 1.95 times and 2.38 times respectively as compared
with that in intact doves. The most remarkable increase of neurogenesis induced
by nucleus ectostriatum lesions was found at the anteriorposterior level 3 (L3),
where the lesion site was located. These results showed that the electrolytic
brain lesion altered the distribution pattern of proliferating cells in the LVZ
and resulted in increased of the number of newborn neurons in the non-VZ areas
of forebrain. The changes in number and distribution pattern of proliferating
cells in LVZ and newborn neurons in forebrain may be dependent on site of
lesion. Studies on the relationship between proliferating cells in LVZ and newly
generated neurons in non-VZ areas may help to understand the mechanism of brain
plasticity and development.
Key
words : Autoradiography, neurogenesis, brain lesion, ring dove.
Antisense
oligonucleotide to insulin-like growth factor II indeces apoptosis in human
ovarian cancer AO cell line
YIN
DE LING, LU PU, GANG PEI
SHANGHAI
Institute of Cell Biology, Chinese Academy of Science, 320 Yue Road, Shanghai
200031, China
ABSTRACT
The
effects of antisense oligonucleotide to insulin-like growth factor II (IGFII) to
induce apoptosis in human fects of antisense to IGFII in ovarian cancer AO cells
were determined by 3H-thymidine incorporation. Apoptosis of the IGFII
antisense-treated cells was quantitated by both nuclear condensation and flow
cytometry after cells were stained with propidium iodide. IGFII antisense (4.5 µM)
treatment of 48 h maximally inhibit proliferation of AO cells More than 25% of
IGFII antisense-treated cells (4.5µM
for 24 h) had undergone apoptosis, whereas less than 3% of the cells were
apoptotic in either IGFII sense-treated cells or untreated cells. Antisense
oligonucleotide to IGFII significantly inhitited cell proliferation and induced
apoptosis in human ovarian cancer AO cell. These data suggest that IGFII may be
a potential target in treatment of ovarian cancer and antisense obligonucleotide
to IGFII may serve as a therapeutic approach.
Key
words: Insulin-like growth factor II (IGFII),antieense obligonucleotide,
apoptosis, human ovarian cancer AO cells.
SANG QING XIANG AMY
Biochemistry Division, Department of Chemistry, Florida State
University, Tallahassee, Florida 32206-4390, USA
ABSTRACT
Matrix
metalloproteinases(MMPs) and tissues inhibitors of metalloproteinases (TIMPs)
play a significant role in regulating angiogenesis the process of new blood
vessel formation. Interstitial collagenase (MMP-1), 72 kDa gelatinase A/type IV
collagenase (MMP-2),and 92 kDa gelatinase B/type IV collagenase (MMP-9) dissolve
extracellular matrix (ECM) and may initiate and promote angiogensis. TIMP-1,
TIMP-2 TIMP-3, and possibly TIMP-4 inhibit neovascularization. A new paradigm is
emerging that matrilysin (MMP-7) ,MMP-9 and metalloelastase (MMP-12) may block
angiogenesis by converting plasminogen to angiostain , which is one of the most
potent angiogenesis antagonists. MMPs and TIMPs play a complex role in
regulating angiogenesis, An understanding of the biochemical and cellular
pathways and mechanisms of angiogenesis will provide important information to
allow the control if angiogenesis , e.g . the stimulation of angiogenesis for
coronary collateral circulation formation; while the inhitition for treating
arthritis and cancer.
Key
words: Collagenases, tissues inhibitors of metalloproteinases,
neovascularization ,plasminogen angiostain converting enzymes, extracellular
matrix.
Cell
surface activation of progelatinese A (proMMP-2) and cell migration
NAGASE
of Biochemistry and Molecular Bio;ogy,University of Kansas Medical Center, 3901
Rainbow Blvd, Kansas Sity KS 66160 Email:
hnagase@kumc.edu
ABSTRACT
Gelatinase
A (MMP-2) is considered to play a critical role in cell migration and invasion.
The proteinase is sectreted from the cell as an inactive zymogen. In vivo it is
postulated that activation of progelationase A(proMMP-2) takes place in the cell
surface mediated by membrane-type
Matrix
metalloproteinases(MT-MMPs). Recent studies have demonstrated that proMMP-2 is
recruited to the cell surface by interacting with tissues inhibitor of
metalloproteinases-2(TIMP-2) bound to MT1-MMP by forming a ternary complex. Free
MT1-MMP closely located to the ternary complex then activates proMMP-2 on the
cell surface. MT1-MMP is found in
cultured invasive cancer cells at the invadopoia . The MT-MMP/TIMP-2/MMP-2
system thus provides localized expression of protelysis of the extracellular
matrix required for cell migration.
Key
words:GelatinaseA, MT-MMPS ,Cell surface activation,TIMP-2, Extracellular
matrix.
Matrix
metalloproteinases and their expression in mammary gland
URIA
JOSE A , ZENA WERB
Department
of Anatomy, University of California San Francisco Ca 94143-0452, USA
ABSTRACT
The
matrix metalloproteinases(MMPs) are a family of zinc-dependent endopeptidases
that play a key role in both normal and pathological processes involving tissue
remodeling events. The expression of these proteolytic enzymes is highly
regulated by a balance between extracellular matrix(ECM) deposition and its
degradation, and is controlled by growth factors,cytokines, hormones,as well as
interactions with the ECM macromolecules. Furthermore, the activity of the MMPs
is regulated by their natural endogenous inhibitors, which are members of the
tissue inhibitor of metalloproteinases(TIMP) family. In the normal mammary
gland, MMPs are expressed during ductal development, lobulo-alveolar development
in pregnancy and involution after lactation, Under pathological conditions, such
as tumorigenesis, the dysregulated expression of MMPs play a role in tumor
initiation, progression and malignant conversion as well as facilitating
invasion and metastasis of malignant cells through degradation of the ECM and
basement membranes.
Key
words: Matrix metalloproteinases,ECM.cancer progression,mammary gland
Phosphorylation
and biosynthesis of high molecular weight proteins of tumor nuclear matrix
BAZARNOVA
TM, TV BULDYAEVA, LS FILATOVA,SB AKOPOV,IB ZBARSKY
NK
Koltzov Institute of Developmental Biology,Russian
Academy
of sciences 26 vavilou Street, 117344 Moscow, Russia
ABSTRACT
Our
previous studies showed a predominance of high molecular weight protein group in
tumor nuclear matrices. Contrary to normal cells, proteins of this group are
preferentially phosphorylated. Phosphoproteins of hepatoma nuclear matrix are
selectively subjected to rapid proteolysis. By alkali treatment and a monoclonal
antibody against phosphotyrosyl residue the presence of two high molecular
weight bands of phosphotyrosyl-containing proteins was detected in nuclear
matrices revealed also a rapid turnover and preferential incopporation of
labeled amino acids selectively inhibited by chloramphenicol
Key
words: Tumors,nuclear matrix, phosphoproteins, phosphotyrosine,
nuclear protein biosynthesis.
The
5’-flanking cis-acting elements of the human ε-globin
gene associates with the nuclear matrix and binds to the nuclear matrix proteins
YAN
ZHI JIANG,RUO LAN QIAN
Shanghai
Institute of Cell Biology, Chinese Academy of sciences,Shanghai 200031,China
ABSTRACT
The
nuclear matrix attachment regions(MARs) and the binding nuclear matrix proteins
in the 5’-flanking cisacting elements of the human
ε-globin
gene have been examined . Using in vitro DNA- matrix binding assay, it has been
shown that the positive stage-specific regulatory element (ε-PREII,
-446bp~- 419bp) upstream of this gene could specifically associate with the
nuclear matrix form K562 cells ,indicating thatεPREII may be an erythroid specific facultative MAR.
In gel mobility shift assay and Southwestern boltting assay, an erythroid-specific
nuclear matrix protein (ε-NMPk)
in K562 cells has been revealed to bind to this positive regulatory element(ε-PREII).
Furthermore, we demonstrated that the silencer(-392bp~177bp) upstream of the
humanε-globin
gene could associate with the nuclear matrices from K562, HEL and Raji cells. In
additionm the nuclear matrix proteins prepared from these cell lines could also
bind to this silencer, suggesting that this silencer element might be a
constitutive nuclear matrix attachment region (constitutive MAR). Our results
demonstrated that the nuclear matrix and nuclear matrix proteins might play an
important role in the regulation of the human
ε-globin
gene expression.
Key
words: Human ε-globin
gene, nuclear matrix attachment regions, nuclear matrix proteins, K562 cells .
A
possible hydrolysis mechanism of ß-naphthyl
acetate catalyzed by antibodies
YUAN
YU REN,ZONG XIANG XIA,CUI HONG YANG,BING HUI YANG,MING YEH
Shanghai
Institute of Cell Biology, Chinese Academy of Sciences China.
Shanghai
Institute of Oraganic Chemistry, Chinese Academy of Science,China
ABSTRACT
The mechanism if ester hydrolysis has been extensively
studied;however, the precise function of active-site residuces in promoting
catalysis is unclear. We describe here the structureal models for the complex of
a catalytic antibody Fv fragment with a phosphonate transition-state analogue ,
constructed by using gene cloning, sequencing and molecular modeling mainly
based on a known X-ray structure of a catalytic antibody. Hydrophobic and
electrostaction analysis of the Fv/analog and Fv/structure interaction suggest
the hydrolysis mechanism: Tyr L91 and Tyr H97 play important roles to stabilize
the ß-naphthyl group of happen through
π-stack;
His H35 donates a pair of free dlectrons at the stom NE2 to an active water and
let it to be a partial hydroxide , which attacks the carbon atom of the carbonyl
group of the substrate. Both his H35 and Arg L96 can form hydrogen bonds and
stabilize the anionic tetrahedral intermediate formed during turnover. This
mechanism emphasizes that an active water bridge may be formed during hydrolysis
process.
Key
words: Catalytic antibody, gene cloning, cDNA sequence, molecular modeling,ester
hydrolysis mechanism
Effects
of laminin glycopeptides on metastasis-related behaviors of cancer cells
JIANG
XIN NONG,ROU LI ZHOU, SHA ZHANG Department of Cell Biology, Beijing Medical
University, Beijing 100083,China
ABSTRACT
Our previous reports have shown that lamininglycopeptides(LN-GPs)
The total glycopeptides prepared from laminin (LN),can prevent the
ecperimental lung metastasis and liver metastasis of mouse cancer cells. In
order to explore the anti-metastasis mechanism of LN-GPs, we studied the effects
of LN-GPs on metastasisrelated behaviors of cancer cells in vitro. LN-GPs did
not affect cell survival. However, LN-GPs did not affect cell survival. However,
LN-GPs inhibited cell attachment and spreading of S180 cells on LN-and Matrigel-substrate
in dese-dependent and time-dependent and time –dependent manners.
Moreover,inhibition of cell attachment and time-dependent manners. Moreover,
inhitition of cell attachment and spreading on Matrigel substrates were much
greater on Matrigel substrate than on LN substrate. In the presence of LN-GPs,
S180 cells on LN substrate. In the presence of LN-GPs, S180 cells on LN
substrate changed from a flattened polygonal shape to a round one , the
migration of S180 cells on LN substrate decreased, and the number of a highly
invasive human pulmonary giant carcinoma PG cells invading Matrigel filter in a
Boyden chamber was reduced. LN-GPs thus have multiple inhibitory effects on
cancer metastasis-related behaviors.
Key words: Laminin, laminin glycopeptides, matrigel, cancer cells,
cancer metastasis.
Enhanced
radioimmunotherapeutic efficacy of a monoclonal antibody cocktail against
SMMC-7721 human hepatocellular carcinoma
SONG
YI QIANG, GEN FENG WANG, XIN LAN DAI,HONG XIE
Shanghai
Institute of Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
ABSTRACT
The improved tumoricidal effect of the
radioantibody mixture(“cocktail”) has been reported recently for the
treatment of colon tumor. In the present study, we demonstrated the enhanced
radiommunotherapeutic efficacy of a monoclonal antibody(Mab) cocktail against
human hepatocellular carcinoma. Therapeutic efficacy was determined by measuring
the change in tumor size over a period, determining the percentage of growth
inhibition of each treatment at various times after radioantibody therapy.
Radioimmunotherapy of SMMC-7221 human hepatoma xenografts in athymic nude mice
with combination of 131Iilabeled Hepama-1 and 131I-labeled
9403 mouse MABs was more effective than using either Hepeam-1 or 9403 Mab alone
.The Mab cocktail could target a greater number of hepatoma cells and increase
the magnitude of hepatoma cell uptake of radioantibodies. The in vitro results
explain the enhanced effect of the Mab cocktail in vivo model system.
Key
words: Mouse monoclonal antibody, human hepatocellular carcinoma,
radioimminotherapy, antibody cocktail.
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