The effect of retinoic acid on the surface charge distribution in cultured human chondrosarcoma and osteosarcoma cells

The effect of retinoic acid on the surface charge distribution in cultured human chondrosarcoma and osteosarcoma cells

Abstracts 17th Meeting Israel Society for Electron Microscopy in d i a m e t e r and w e r e u s u a l l y s t r a i g h t and non-anastomosing. We d ...

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Abstracts 17th Meeting Israel Society for Electron Microscopy in d i a m e t e r and w e r e u s u a l l y s t r a i g h t and non-anastomosing. We d i d not find any u l t r a s t r u c t u r a l d i f f e r e n c e s in the amyloid of two c l i n i c a l types of A m [ l o i d o s i s cutis (Lichen a m y l o i d o s i s and M a c u l a r a m y l o i d o s i s ) e x c e p t for some e p i d e r m a l changes. O u r r e s u l t s s u g g e s t that e x a m i n a t i o n by e l e c t r o n m i c r o s c o p y is r e q u i r e d for a d e f i n i t e d i a g n o s i s of A m y l o i d o s i s curls.

in the h u m a n O s t e o s a r c o m a and C h o n d r o s a r coma t u m o r cells the e x p r e s s i o n of cellular p r o p e r t i e s , w h i c h are o f t e n a s s o c i a ted w i t h the t r a n s f o r m e d p h e n o t y o e .

E L E C T R O N M I C R O S C O P Y OF IRON S T O R A G E E R Y T H R O L E U K E M I C CELLS T R E A T E D W I T H ACETYL PHENYL HYDRAZINE E. R a h a m i m , E. F i b a c h , and M. K e s s e l *

THE E F F E C T OF R E T I N O I C A C I D ON THE S U R F A C E C H A R G E D I S T R I B U T I O N IN C U L T U R E D HUMAN CHONDROSARCOMA AND OSTEOSARCOMA CELLS Y. M a r i k o v s k y ,

L. M e r o m s k y *

and R. L o t a n *

Departments of Membrane Research and *Biophysics, The W e i z m a n n I n s t i t u t e o f Science, Rehovot 76100, Israel

R e t i n o i d s , a g r o u p of n a t u r a l a n d synt h e t i c v i t a m i n A analogs, can e x e r t prof o u n d e f f e c t s on f u n d a m e n t a l c e l l u l a r p r o c e s s e s such as g r o w t h and d i f f e r e n t i a tion of normal, t r a n s f o r m e d a n d t u m o r cells in v i v o and in culture. The e f f e c t of 8 - a l l - t r a n s - r e t i n o i c a c i d (RA) on the s u r f a c e m e m b r a n e of two s a r c o m a cell lines, H s 7 9 1 d e r i v e d f r o m h u m a n O s t e o s a r coma and H s 7 0 5 d e r i v e d from h u m a n C h o n d rosarcoma, was investigated. Cell surface g l y c o p r o t e i n s w e r e l a b e l l e d on unt r e a t e d a n d on R A - t r e a t e d cells b y N a I O 4 - N a B 3 H 4, or b y n e u r a m i n i d a s e and g a l a c t o s e o x i d a s e - N a B 3 H 4. L a b e l l i n g of s e v e r a l g l y c o p r o t e i n s was e n h a n c e d 2 to 4 fold b y t r e a t m e n t w i t h i0 ~m RA. The d i s t r i b u t i o n of a n i o n i c sites on these two cell lines w a s t e s t e d w i t h c a t i o n i c f e r r i t i n (CF), a p o l y c a t i o n i c ligand. C e l l s w e r e i n c u b a t e d b r i e f l y w i t h CF, then fixed, e m b e d d e d and t h i n - s e c t i o n e d for e l e c t r o n m i c r o s c o p y (EM). Analysis by t r a n s m i s s i o n E M r e v e a l e d that CF ind u c e d a r e d i s t r i b u t i o n and g r o u p i n g of cell s u r f a c e a n i o n i c sites into c l u s t e r s and p a t c h e s , a s u r f a c e c h a r g e d i s t r i b u tion c h a r a c t e r i s t i c , w h i c h has o f t e n b e e n o b s e r v e d in v a r i o u s m a l i g n a n t t r a n s f o r m e d cell systems. Some cells e x h i b i t large portions of unlabelled surface membrane w i t h few s m a l l CF clusters, w h i l e o c c a s i o n a l m e m b r a n e p r o c e s s e s s h o w h e a v y CF patches. Treatment with RA inhibited c l u s t e r a n d p a t c h f o r m a t i o n of C F - s p e c i f ic b i n d i n g sites, thus p r o d u c i n g an e v e n ly d i s t r i b u t e d and c o n t i n u o u s CF label, as does g l u t a r a l d e h y d e f i x a t i o n p r i o r to i n c u b a t i o n of u n t r e a t e d cells w i t h CF. The r e s u l t s d e m o n s t r a t e the a b i l i t y of R A to m o d i f y the p r o d u c t i o n , g l y c o s y l a tion a n d m o b i l i t y o f cell s u r f a c e c o n s t i tuents as o b s e r v e d in EM. Our results s u p p o r t the findings that R A s u p p r e s s e s

335

IN

E. R a c h m i l e w i t z

Department of Hematology, Hadassah University Hospital, and *Department of Membrane and Ultrastructure Research, Hebrew University - Hadassah Medical School, Jerusalem 91010, Israel

M ~ s s b a u e r s p e c t r o s c o p y has d e t e r m i n e d that t r e a t m e n t of m u r i n e e r y t h r o l e u k e m i c cells (MEL) w i t h 0.01 - 0.02% a c e t y l p h e n y l h y d r a z i n e (APH) r e s u l t e d in g r a d ual d e n a t u r a t i o n of h e m o g l o b i n (Hb) and i n c o r p o r a t i o n of the r e l e a s t e H b - i r o n into ferritin. We h a v e e x a m i n e d the ult r a s t r u c t u r a l a p p e a r a n c e of i r o n - c o n t a i n ing s t r u c t u r e s in M E L c u l t u r e d in media: (a) s u p p l e m e n t e d w i t h iron c i t r a t e for s i x days, (b) w i t h the a d d i t i o n of d i m e t h y l s u l f o x i d e (DMSO) to i n d u c e e r y t h r o i d d i f f e r e n t i a t i o n , and (c) in cells o r i g i n a t i n g from this p o p u lation which were incubated with APH for 24 hrs. Previous electron microscope observations I s h o w e d that the a c c u m u l a t i o n and iron s t o r a g e in D M S O - i n c u b a t e d cells w a s f o u n d to be in d o u b l e - m e m b r a n e e n c l o s e d v e s i c l e s m e a s u r i n g 0.2 - 0.5 ~m w i t h loosely packed electron-dense particles of ferritin. Two d i f f e r e n t forms of f e r r i t i n - c o n t a i n i n g o r g a n e l l e s h a v e b e e n o b s e r v e d in the p r e s e n t study. Type I c o n t a i n s close-packed or homogeneously distributed ferrugineous material. Type II has an intralamellar appearance with evidence of l o o s e l y d i s p e r s e d g r a n u l a r content. In u n d i f f e r e n t i a t e d cells only the first type of o r g a n e l l e is p r e s e n t , w h e r e a s in the cells i n c u b a t e d w i t h D M S O alone, there is no i n d i c a t i o n o f f e r r i t i n s t r u c tures at all. H o w e v e r , in d i f f e r e n t i a t e d cells i n c u b a t e d w i t h D M S O and A P H b o t h types of s t r u c t u r e w e r e found, i n d i c a t i n g a s p e c i f i c r e a c t i o n to APH. C e l l s w e r e p r e p a r e d for e l e c t r o n m i croscopy by conventional glutaraldehydeo s m i u m t e t r o x i d e f i x a t i o n in 0.i M s a l i n e b u f f e r e d to p H 7.2. In an a t t e m p t to i d e n t i f y c l e a r l y the e l e c t r o n - d e n s e iron c l u s t e r s of ~ e r r i t i n w i t h i n the organelles s e c t i o n s w e r e not c o u n t e r - s t a i n e d w i t h u r a n y l a c e t a t e and lead citrate. i. s. ofer et al., Blood 58 (1981) 255.