the oligonucleotides of the invention may be prepared according to known methods , as described for instance in tetrahedron 39 : 3 , 1983 ; ann . rev . biochem . 53 : 323 , 1984 ; &# 34 ; oligonucleotide synthesis ; a practical approach &# 34 ;, yait m . j . ed . irl press ., oxford , u . k . 1984 ; chem . rev . 90 ( 4 ) 543 , 1990 . the oligonucleotides of the invention will also preferably be stabilized in order to improve the cell penetration and to prolong half - life , using conventional structural modifications , such as disclosed for instance in chem . rev . 90 ( 4 ), 543 , 1990 . these modifications mainly but not exclusively concern the internucleotidic phosphate bridge which may be transformed in a methylphosphonate , phosphorothioate or phosphorodithioate , phosphoroamidate groups , phosphate esters etc . the derivatives completely substituted or substituted at the 3 &# 39 ;- and 5 &# 39 ; end with phosphorothioate residues are particularly preferred . the oligonucleotides may also be covalently bound to a lipid , as diclosed for instance in wo 90 / 10448 , so as to make the transport through the cell membranes easier to be then cleaved to the active oligonucleotides by cytoplasmatic enzymes . for the intended therapeutic uses , particularly for the treatment of primary or secondary neoplastic diseases , as well as of other pathological forms wherein the overexpression of urokinase receptor is a pathogenetic event , the invention refers also to pharmaceutical compositions containing the antisense oligonucleotides of the invention in admixture with carrier suited for the oral or parenteral administration . the compositions of the invention , prepared according to conventional methods such as disclosed for instance in &# 34 ; remington &# 39 ; s pharmaceutical sciences handbook &# 34 ;, mack pub . co ., ny , usa , xvii ed ., will contain from 0 . 1 to 100 mg of the oligonucleotide and they will be generally administered from 1 to 4 times a day , according to the physician &# 39 ; s prescription . according to a particularly preferred embodiment , the oligonucleotides are formulated in liposomial form , particularly in cationic liposomial form , using dotap ( boehringer mannheim ) according to known methods ( biochem . biophys . res . commun . 107 : 818 - 825 , 1993 ). the invention will now be described more in detail in the following examples . this nucleotide was substituted with phosphorothioate residues at the 3 &# 39 ;- and 5 &# 39 ;- end , according to known methods . the obtained oligonucleotides , purified by hplc , was pre - incubated at 37 ° c . for 35 &# 39 ; in the presence of dotap , sterilized thorugh a 0 . 2 μm filter and applied to the culture medium containing 10 % heat - inactivated fcs ( gibco , usa ) at final concentrations of 10 μm of oligonucleotide and 13 μm of dotap . the cell lines wi - 38 ( human embryonic lung fibroblasts ) and va - 13 cells , obtained from the cell line wi - 38 by transformation with the virus sv 40 were used . said cells are commercially available from flow laboratories ( milano , italy ), and cultured in dulbecco &# 39 ; s modified medium supplemented with 10 % fetal calf serum , in an atmosphere of 5 % co 2 - 95 % air at 37 ° c . the transformed va - 13 cells , characterized by the overexpression of u - par and the wi - 38 normal cells were seeded at 20 × 10 3 cells / well in 24 - well petri dish in dmem containing 10 % heat - inactivated fcs . the oligonucleotide / dotap complex of example 1 was added to the culture medium at a concentration of 10 μm and the dishes were incubated at 37 ° c . for 4 days . to keep the oligonucleotide concentration constant , a second addition of the oligonucleotide / dotap complex of example 1 was performed 48 hours later , at a concentration of 5 μm . aliquots of the medium of both cell lines , grown to confluence in 25 cc falcon flasks , were used directly in cross - linking experiments . cell monolayers were washed twice with pbs and subjected to acid washing to uncouple endogenous u - pa from the receptor . after neutralization and further washing in pbs , cells were lysed in the flasks with 500 μl lysis buffer ( 0 . 5 % chaps , 0 . 1m tris - hcl ph 8 . 0 , 10 mm edta , 1 % aprotinin , 1 % triton x 114 , 1 mm phenylmethane - sulfonyl fluoride pmsf ! and the mixture was centrifuged . in parallel cultures , cells were detached with 500 pl edta in pbs and centrifuged . the pellet was lysed in 500 μl lysis buffer and an aliquot was used for cross - linking . the material eventually remaining on the flask after edta detachment ( sam , surface attached material ) was washed 5 times with 10 ml pbs and extracted with 500 μl lysis buffer and an aliquot was subjected to cross - linking , using radiolabelled atf ( amino terminal residue of 140 amino acids of human u - pa ). 50 μl of each sample were incubated with 500 × 10 3 cpm of 125 i - atf with or without 100 mm unlabelled u - pa for 60 min at 4 ° c ., then n , n &# 39 ;- disuccinimidyl suberate ( final concentration 1 mm ) was added , the mixture was incubated at room temperature for 15 min . and cross - linking was stopped by addition of ammonium acetate to 10 mm . the samples were then analyzed by sds - page under non reducing conditions and autoradiography . the obtained results prove that the 4 day - exposure of va - 13 cells to a 10 μm concentration of antisense oligonucleotide caused a remarkable decrease in u - par at the cell surface . competition - binding experiments performed on acidified va - 13 monolayers indicated a remarkable decrease of u - par following a treatment with the oligonucleotide : 37 . 5 (± 6 . 3 )× 103 receptors / cell . the oligonucleotide - treated cells were subjected to the invasion assay to evaluate their ability to penetrate the basement membrane matrigel , in the presence of the wi - 38 conditioned medium in the lower compartment of the migration chamber . the basement membrane matrigel , an extract of the the englebreth - holm - swarm tumour , commercially available from collaborative research , was used as a stock solution with a protein concentration of 10 mg / ml . blind well chemotaxis chambers with 13 - mm diameter filters were used for the invasion assay . polyvinylpyrrolidone - free polycarbonate filters , 8 μm pore size ( nuclepore , calif . ), were coated with 50 μg / filter of matrigel . the matrigel was diluted to the final concentration with cold distilled water , applied to the filters , dried under a hood , and reconstituted with serum - free medium . the coated filters were placed into boyden chambers . cells ( 40 × 10 3 ), suspended in serum - free dmem , were added to the upper chamber . conditioned medium ( obtained from wi - 38 human fibroblasts maintained in , culture in serum - free conditions for 24 h after confluence ) was placed into the lower compartment of the boyden chamber . this medium was used as a source of chemoattractants . alternatively , u - pa was placed into the lower compartment of the migration chamber . cell migration in the absence of chemoattractants ( dmem alone ) in the lower compartment , was taken as background migration for each cell line over a 5 hours period . cell migration could not be attributed to passive diffusion since the pore size of the filters is smaller than the cells . in some experiments , cells in the upper compartment of the migration chamber were incubated with monoclonal antibodies in order to obtain an immunosuppression of the invasive process . assays were carried out at 37 ° c . in 5 % co 2 for 5 hours . at the end of incubation filters were removed and fixed in methanol for 2 hours . the cells on the upper part of the filters were then completely removed by wiping with a rubber swab . the filters were stained with fucsin and all the cells attached to the lower surface , that is the invasive cells , were counted . each assay was performed in quadruplicate . these conditions revealed the highest differences between normal and transformed cells , either in the absence or in the presence of monoclonal antibodies ( mab r3 and mab 5b4 ) in the upper compartment of the invasion system . fig1 shows that the oligonucleotide treatment resulted in a considerable decrease in cell invasivity . the number of cells on the underside of the migration filter resulted even lower than under conditions of spontaneous random migration , approaching that of wi - 38 cells . as a control , a non - sense oligonucleotide ( nsodn ) having the same base composition as the anti - senge oligonucleotide ( aodn ) of example 1 , but with a scrambled sequence . in order to verify that the loss of the invasive properties and the remarkable decrease in membrane u - par of the treated va - 13 cells is actually a consequence of the anti - messenger - mediated u - par gene expression inhibition , u - par mrna levels of the va - 13 cells treated with the oligonucleotide of example 1 were measured . an internal standard - based quantitative rt - pcr assay was used ( cancer res . 52 , 108 - 116 , 1992 ). as shown in fig2 a 4 - day exposure of va - 13 cells to 10 μm aodn vehiculated by 13 μm dotap resulted in a dramatic decrease ( more than 80 %) of u - par mrna levels as compared with both the untreated and random - sequence oligonucleotide treated controls . therefore , as evidenced by this assay , the final steady - state levels of u - par gene mrna in the treated cells are similar to those of normal untreated wi - 38 cells . this result indicates a complete reversion of u - par gene overexpression , as a consequence of the aodn administration . __________________________________________________________________________sequence listing ( 1 ) general information :( iii ) number of sequences : 1 ( 2 ) information for seq id no : 1 :( i ) sequence characteristics :( a ) length : 18 base pairs ( b ) type : nucleic acid ( c ) strandedness : single ( d ) topology : linear ( ii ) molecule type : cdna ( iii ) hypothetical : no ( iii ) anti - sense : yes ( xi ) sequence description : seq id no : 1 : cggcgggtgacccatgtc18__________________________________________________________________________
antisense oligonucleotides optionally stabilized with phosphorotioate residues or analogues , or modified in the whole sugar - phosphate backbone -- complementary to the human urokinase receptor messenger rna -- are able to prevent invasiveness of neoplastic cells by inhibiting the overexpression of the receptor itself , directly responsible of the invasive phenotype . said oligomers are useful as medicaments for the treatment of primary and secondary neoplasias as well as of other pathologies wherein the urokinase receptor gene overexpression is a pathogenic event .