THURSDAY 2 APRIL
POSTERSRELATEDTOS30
Thu-S30-29
THE FIBRIN SPLITING ACTIVITY OF TUMOR CELLS
AND THE INHIBITION OF THIS ACTIVITY BY SERA
(XlWR3L OF YEAST F'RWIOSE-1,6-BISPIFOSPE4TASE BY
cDV"T KDIFICATICN AND PRYlW3LYSIS
A . 4 . Lenz, P. Tortma, and H. Holzer
Biserka Nagy and B. B r d a r
C e n t r a l Institute f o r T u m o r s and Allied D i s e a s e s ,
Ilica 1 9 7 , 41000 Z a g r e b , Yugoslavia.
Abteilung fiir hzymchemie d e r GSF, I n g o l s a d t e r
Landstr.1, D-8042 Neuherbery,and Bicchem. I n s t .
der UniversiISt, D-7800 Freiburg, West- Germany
In i n t a c t yeast cells fructose-l,6-bisphosphatase
The fibrinolytic activity of t u m o r cells d e r i v e d f r o m
a highly m e t a s t a s i z i n g m a m m a r y c a r c i n o m a and
f r o m a low m e t a s t a s i z i n g f i b r o s a r c o m a w e r e studie d employing a r e a c t i o n between t u m o r cell l y s a t e s
and plasminogen. The production of plasmiiiogen
a c t i v a t o r by cells of both t u m o r s is followed by t h e
a p p e a r a n c e of i n c r e a s e d activity of sera f r o m tum o r bearing m i c e t o inhibit the reaction.The activity of human sera t o inhibit t u m m cell f i b r i n o l y s i s
w e r e examined also. However, sera f r o m t u m o r
patients w e r e m o r e inhibitory than n o r m a l sera.
was very r a p i d l y inactivated after a d d i t i o n of
glucose t o the culture medium. Resuspension of
cells i n an acetate c o n t a i n i n g medium r e s u l t e d i n
a reactivatim of enzyme a c t i v i t y e ~ in
n presence
of cyclohexhide.Qanide andccCPprwented reactiv a t i o n thus i n d i c a t i n g energy dependency.Using
specific antiserum it was Shawn that i n the f i r s t
20 min of incubatim w i t h glucose s p e c i f i c c a t a l y t i c activity decreased to 40% of the i n i t i a l v a l u e
whereas the amxlnt of cross reacting material remined constant and only thereafter decreased rap i d l y . I t is concluded that c o v a l e n t m d i f i c a t i o n
of the enzyme to a less active form initiates prot e o l y s i s . T h i s might be one example of a more general nledmnl' s m leading to a selective p r o t e o l y s i s .
Th~S30-30
THE EFFECT OF SYNTHETIC COPOLYMER SIDE-CHAIN COMPOSITION ON SUSCEPTIBILITY TO LYSOSOMAL HYDROLYSIS.
R.Duncan, J .Kope&k* and J .B.Lloyd, Dept .Biological
Sciences, University of Keele, Staffs.,England 8
*Institute of Macromol.Chem.,Prague,Czechoslovakia.
SYNTHESIS OF PLASMINOGEN ACTIVATOR BY CYCLING CELLS
J. SoriC and B. B r d a r
C e n t r a l Institute for T u m o r s and Allied D i s e a s e s ,
I l i c a 1 9 7 , 41000 Z a g r e b , Yugoslavia.
Attachment of drugs to synthetic polymers affords
a potential mechanism for their direction to the
specific cells where action is required.Intracellular release of drugs would be controlled by
the susceptibility of the pharmacon-polymer linkage to lysosomal hydrolysis.Peptidy1 side chains
of a methacrylamide-based copolymer showed different degrees of lysosomal hydrolysis dependent
on their composition.Whereas side chains -Gly-BAla
-Tyr-p-nitroanilide were completely resistant to
hydrolysis by rat visceral yolk sacs cultured &
vitro, -Gly-Ileu-Tyr-NAp was slowly degraded and
-Gly-Gly-Tyr-NAp and -Gly-Phe-Tyr-NAp were
digested more rapid1y.Incubation of twentytwo
different copolymers with rat liver Tritosomes
also revealed different susceptibilities of the
side-chains to hydrolysis.
The s y n t h e s i s of plasminogen a c t i v a t o r (PA) by synchronized both n o r m a l and RSV-transformed chick
f i b r o b l a s t s h a s been studied. The PA activity o f c e l l
l y s a t e s w a s a s s a y e d on 1251-fibrin-coated P e t r i
d i s h e s and w a s e x p r e s s e d a s the radioactivity relea s e d f r o m t h e p l a t e s . I t w a s found that n o r m a l cells
p r o d u c e d e t e c t a b l e l e v e l s of PA only in the S-phase
and during or b e f o r e m i t o s i s .In c o n t r a s t , t r a n s f o r med cells s y n t h e s i z e t h i s e n z y m e throughout t h e
e n t i r e cell c y c l e reaching maximum in the G2-M
p e r i o d s . F u r t h e r m o r e the a p p e a r a n c e of PA activity following f i b r o b l a s t s infection with RSV depends
both on t h e s y n t h e s i s of c e l l u l a r DNA and c e l l division.
INHIBITION OF PLASMINOGEN ACTIVATOR PRODUCTION
BY S-ADENOSYL HOMOCYSTEINE ANALOGUES.
UPTAKE AND DEGRADATION OF A SYNTHETIC COPOLYMER BY
RAT VISCERAL YOLK SACS CULTURED IN VITRO.
R.Duncan,J .Kopeyek* and J.B .Lloyd,Dept Biological
Sciences, University of Keele, Staffs., England &
*Institute of Macromol.Chem.,Prague,Czechoslovakia.
.
A methacrylamide-based copolymer containing side-
chains -Gly-Gly-Tyr-p-nitroanilide was 1251labelled and its uptake by yolk sacs measured.Pr-ogressive accumulation of radioactivity by the
tissue ceased after 3-4h of a 7h incubation period,
but the culture medium contained increasing concentrations of a low mol.wt. radioactive product.
2,4-Dinitrophenol inhibited both tissue accumlation of radioactivity and the appearance of degradation products in the culture medium, indicating that copolymer is captured by pinocytosis with
subsequent lysosomal hydrolysis of the side chains.
Inclusion of leupeptin in the culture medium resulted,by complete inhibition of digestion, in a
sustained accumlation of radioactivity by the
tissue.The rate of uptake of the copolymer was the
same as that previously reported for the fluidphase pinocytic marker,1251-labelled PVP.
Michele VEDEL, Christiane TEMPETE and Malka
ROBERT-GERO, Institut de Chimie des Substances
Naturelles CNRS 91190 Gif sur Yvette France.
The effect of S-adenosyl-homocysteine (SAH),(the
natural inhibitor of transmethylases),was studied
on both cell associated and released plasminogen
activator production (PA), in various normal and
transformed cell lines. Our results show that all
the good inhibitors of virus induced cell transformation inhibit PA production. The fact that PA
production could also be inhibited in already
transformed cells without any effect on morphology suggests a lack of correlation between PA production and the transformed cell morphology.
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