POLYPEPTIDES DERIVED FROM ENDOSTATIN EXHIBITING ANTIANGIOGENIC ACTIVITY

Abstract: Polypeptides with sequence corresponding or homologous to that of endostatin, having inhibiting activity on angiogenesis, are useful in the treatment of angiogenesis-dependent tumors.

Description: POLYPEPTIDES DERIVED FROM ENDOSTATIN EXHIBITING ANTIANGIOGENIC ACTIVITY The present invention relates to polypeptides with antiangiogenic activity. TECHNOLOGICAL BACKGROUND Angiogenesis, the outgrowth of new capillaries from pre-existing vessels, is essential for physiological and pathological conditions including tumor growth and metastasis (1-3) . Angiogenesis is a complex multistep process that includes proliferation, migration and differentiation of endothelial cells, degradation of extracellular matrix, microtubule formation and sprouting of new capillary branches (3,4) . Endostatm is a 22 kDa C-termmal fragment of collagen XVIII that specifically inhibits endothelial proliferation m vitro and potently inhibits angiogenesis and tumor growth in vivo (5) . Systemic administration of non refolded precipitated protein expressed in E. coli caused growth regression of experimental tumors in mice (5,6). We reported that human full-length endostatm produced by E. coli expression system is able to block fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF) induced proliferation and migration of microvascular endothelial cells (7) . The production of large amount of endostatm can be difficult. Thus the availability of smaller molecule with sequence homology with endostatm endowed with biological activity can be useful . The present invention relat.es to polypeptides comprising ten to sixty ammo acid residues witn a sequence corresponding or Homologous to that of endostatm, having angiogenesis -mnioitmg activity, useful for the treatment of angiogenesis-dependent tumours . The present invention also relates to a process for the preparation of said polypeptides. The invention further relates to pharmaceutical formulations containing one or more of said polypeptides. Endostatin is a protein having antiangiogenic activity, isolated by J. Folkman and M. O'Reilly (EP 0 857 210) . Examples of the polypeptides prepared according to the invention are the following. (I) nonatriacontapeptide: His-Thr-His-Gln-Asp-Phe-Gln- Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Thr-Pro-Leu-Ser- Gly-Gly-Met-Arg-Gly-Ile-Arg-Gly-Ala-Asp-Phe-Gln- Cys (tBu) -Phe-Gln-Gln-Ala-Arg-Ala (II) pentacontapeptide: Val-Gly-Leu-Ser-Gly-Thr-Phe-Arg- Ala-Phe-Leu-Ser-Ser-Arg-Leu-Gln-Asp-Leu-Tyr-Ser-Ile- Val-Arg-Arg-Ala-Asp-Arg-Gly-Ser-Val-Pro-Ile-Val-Asn- Leu-Lys-Asp-Glu-Val-Leu-Ser-Pro-Ser-Trp-Asp-Ser-Leu- Phe-Ser-Gly (IΙI)pentatetracontapeptide: Ser-Gln-Gly-Gln-Val-Gln-Pro- Gly-Ala-Arg-Ile-Phe-Ser-Phe-Asp-Gly-Arg-Asp-Val-Leu- Arg-His-Pro-Ala-Trp-Pro-Gln-Lys-Ser-Val-Trp-His-Gly- Ser-Asp-Pro-Ser-Gly-Arg-Arg-Leu-Met-Glu-Ser-Tyr (IV) pentacontapeptide: Cys-Glu-Thr-Trp-Arg-Thr-Glu-Thr- Thr-Gly-Ala-Thr-Gly-Gln-Ala-Ser-Ser-Leu-Leu-Ser-Gly- Arg-Leu-Leu-Glu-Gln-Lys-Ala-Ala-Ser-Cys-His-Asn-Ser- Tyr-Ile-Val-Leu-Cys (tBu) -Ile-Glu-Asn-Ser-Phe-Met-Thr- Ser-Phe-Ser-Lys . These polypeptides have remarkable antiangiogenic activity in the in vitro inhibition test on endothelial cells proliferation and migration (16) . More particularly, nonatriacontapeptide I turned out to be equipotential to endostatin. The process for the preparation of the polypeptides of the invention is based on the following general methods and reactions used in peptide synthesis. Amino groups of the amino acids can be protected by use of the 9-fluorenylmethoxycarbonyl (Fmoc) , tert- butoxycarbonyl (Boc) , benzyloxycarbonyl (Z) , trityl (Trt) groups and other groups commonly used in peptide chemistry. The carboxylic group can be protected by means of the tert-butyl ester, benzyl ester, p-methoxybenzyl ester and others conventionally used for said purposes . These protective groups, as it will be illustrated in detail in the examples, can be removed according to processes known in literature, such as by treatment with trifluoroacetic acid, anhydrous hydrofluoric acid, piperidine and the like, according to circumstances . The amino acids can be condensed by using active esters such as pentafluorophenyl ester (OPfp) , 3-hydroxy-4-oxo-3 , 4-dihydro-l , 2 , 3 -benzotriazine ester (ODhbT) , or carboxy-activators such as benzotriazol- 1-yl-oxy-tris-pyrrolidino-phosphonium hexafluorophosphate (PyBop) , 2- (lH-benzotriazol-l-yl-1, 1, 3 , 3 -tetramethyl) - uronium tetrafluoroborate (TBTU) and the other activators conventionally used for this type of reactions . The purification of the polypeptides described in the present invention can also be carried out according to known techniques of protein chemistry, such as reverse phase HPLC, gel filtration, ion exchange chromatography and preparative electro- phoresis . For example, the process of the present invention can be carried out as follows, using the solid phase peptide synthesis and the automatic synthesizer Biolynx plus, mod. 4170 by Novabiochem (Nottingham, Great Britain) (17) . The protection of the α-a mo groups the ammo acids is carried out by use of 9-fluorenylmethoxycarbonyl (Fmoc) . The functional groups of the ammo acids side chains are protected using the following protective groups: tert-butyl for aspartic acid, glutamic acid, ser e, threomne and tyrosme; tert-butoxycarbonyl for lysme and trypthophan; tπtyl for histidine; 2,2,4,6,7- pentamethyl-dιhydro-benzofuran-5-sulfonyl for argmme; tert-butyl for cysteme of polypeptide I and for the third cysteine of polypeptide IV; tπtyl for the two other cyste es of polypeptide IV. The synthesis is gradually carried out starting from the C-terτninal Fmoc-ammo acid, attached to a resin by an ester bond, consisting of polyethyleneoxide grafted to a polystyrene matrix and functionalized by a 4- hydroxymethyl-phenoxyacetic acid residue (18) . Fmoc is removed by using a solution of pipeπdme m dimethylformamide (DMF) . Pentafluorophenyl esters of Fmoc- ammo acids are generally used for the condensation reactions. In the case of serme and threomne, the use of ODhbt esters was preferred, whereas in the case of argmme and histidme the carboxylic group was activated by PyBop in the presence of diisopropylethylamme, with three hour reaction times. To maximize the reaction yields, a five equivalent excess of Fmoc-ammo acid is used. The times of deprotection and condensation reactions are automatically determined by the synthesizer; the technician will select the acylation times only m the case of activation with PyBop. The peptide is cleaved from the resin, at the same time removing all the protective groups, by acidolysis with trifluoroacetic acid in the presence of 5% anisole and 1% ethanedithiol . The resulting crude polypeptides are purified by reverse phase semipreparative HPLC, using a column (250 x 10 mm) filled with Source TM 15 RPC (Pharmacia Biotech AB, Uppsala, Sweden) . Polypeptides are eluted with a linear gradient from 0% to 60% of acetonitrile in 0.1% aqueous TFA, at a 5 ml/min flow rate with detection at 226 nm; 10- 15 mg of product are loaded for each run. The main fractions are collected and freeze-dried. The purified polypeptides are characterized by amino acid analysis and electrospray mass spectrometry with a Finnigan Mat apparatus mod. LCQ. The present invention also relates to the pharmaceutical compositions comprising the polypeptides of the invention or a non toxic salt thereof, in mixture with a suitable diluent or carrier. The following examples further illustrate the invention without limiting it. Example 1 His(Trt) -Thr(tBu) -His- (Trt) -Gin-Asp (OtBu) -Phe-Gln-Pro-Val- Leu-His(Trt) -Leu-Val-Ala-Leu-Asn-Thr (tBu) -Pro-Leu- Ser (tBu) -Gly-Gly-Met-Arg (Pbf) -Gly-Ile-Arg (Pbf) -Gly-Ala- Asp (OtBu) -Phe-Gln-Cys (tBu) -Phe-Gln-Gln-Ala-Arg (Pbf) -Ala- resin. 500 mg (0.1 mmoles) of Fmoc-Ala-resin were suspended in 20 ml of DMF and after 2 hours they were loaded into the reaction column. The Fmoc-amino acid-resin was then subjected to the following treatments: a) washings with DMF; b) removal of Fmoc by treatment with a 20% piperidine solution in DMF; c) washings with DMF; d) condensation with the suitable Fmoc-amino acid active ester (5 equivalents) in the presence of N-hydroxy-benzotriazole (5 equivalents) as catalyst, with the addition of an anionic dye (Novachrome, Calbiochem-Novabiochem AG, Laufelfingen, Switzerland) for automatically monitoring the reaction time. The carboxyl was activated by using PyBop, without addition of dye, only in the case of Fmoc-Arg (Pbf) and Fmoc-His (Trt) . This cycle of operations was repeated thirty-eight times with the suitable Fmoc-amino acid to finally obtain the protected resin-nonatriacontapeptide . The product was then placed in a sintered glass funnel and washed in succession with DMF, tert-amyl alcohol, acetic acid, tert- amyl alcohol, methylene chloride and ethyl ether. After drying under vacuum, 760 mg of protected resin- nonatriacontapeptide were obtained. Example 2 His-Thr-His-Gln-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala- Leu-Asn-Thr-Pro-Leu-Ser-Gly-Gly-Met-Arg-Gly-Ile-Arg-Gly- Ala-Asp-Phe-Gln-Cys (tBu) -Phe-Gln-Gln-Ala-Arg-Ala (nonatriacontapeptide I) . 760 mg of protected resin-nonatriacontapeptide were suspended in 141 ml of TFA and added with 7.5 ml of anisole and 1.5 ml of ethanedithiol and the mixture was reacted for 2 hours with occasional stirring. After filtration under vacuum, the resin was washed with TFA (2 x 50 ml) . The filtrate was added with dry ethyl ether to precipitate the polypeptide. The product was filtered, repeatedly washed with dry ethyl ether and finally dried under vacuum over KOH. Nonatriacontapeptide I was purified by semipreparative HPLC as described above, to obtain 195 mg of pure nonatriacontapeptide. [a] -43.0°(c = 0.5, water). Mass spectrum: molecular peak (M+l) = 4376 Da. Amino acid analysis: Asp = 3.1(3); Thr = 1.98(2); Ser = 0.99(1); Glu = 5.2(5); Pro = 1.8(2); Gly = 3.95(4); Ala = 3.98(4); Cys = 1.1(1); Val = 1.97(2); Met = 0.96(1); He = 1.2(2); Leu = 4.2(4); Phe = 2.98(3); His = 3.1(3); Arg = 2.96(3) . Example 3 Val-Gly-Leu-Ser(tBu) -Gly-Thr (tBu) -Phe-Arg (Pbf) -Ala-Phe- Leu-Ser (tBu) -Ser (tBu) -Arg (Pbf) -Leu-Gin-Asp (OtBu) -Leu- Tyr(tBu) -Ser (tBu) -Ile-Val-Arg (Pbf) -Arg (Pbf) -Ala-Asp (OtBu) - Arg (Pbf) -Gly-Ser (tBu) -Val-Pro-Ile-Val-Asn-Leu-Lys (Boc) - Asp (OtBu) -Glu (OtBu) -Val-Leu-Ser (tBu) -Pro-Ser (tBu) - Trp(Boc) -Asp (OtBu) -Ser (tBu) -Leu-Phe-Ser (tBu) -Gly-resin. 770 mg (0.1 mmoles) of Fmoc-Gly-resin were suspended in 30 ml of DMF and after two hours were loaded into the reaction column. The operations described in example 1 were then repeated for forty-nine times, using the suitable Fmoc-amino acid in each run. In this synthesis also, the Fmoc-Arg (Pbf) and Fmoc- His(Trt) carboxylic groups were activated with PyBop, those of Fmoc-Ser (tBu) and Fmoc-Thr (tBu) with Dhbt ester, whereas for all the other Fmoc-amino acids the Pfp ester was used. After assembling all of the amino acids, the product was washed as described in example 1, and dried under vacuum. 1200 mg of protected resin-pentacontapeptide were obtained. Example 4 Val-Gly-Leu-Ser-Gly-Thr-Phe-Arg-Ala-Phe-Leu-Ser-Ser-Arg- Leu-Gin-Asp-Leu-Tyr-Ser- lie-Val-Arg-Arg-Ala-Asp-Arg-Gly- Ser-Val-Pro-Ile-Val-Asn-Leu-Lys-Asp-Glu-Val-Leu-Ser-Pro- Ser-Trp-Asp-Ser-Leu-Phe-Ser-Gly (pentacontapeptide II) . 1200 mg of protected resin-pentacontapeptide were treated with 188 ml of TFA, 10 ml of anisole and 2 ml of ethanedithiol . Then the procedure described in example 2 was followed. 140 mg of pure pentacontapeptide were obtained. [a] -12.5° (c=0.04 , water). Mass spectrum: molecular peak (M+l) = 5514 Da. Amino acid analysis: Asp = 4.89(5); Thr = 1.02(1); Ser = 8.91(9); Glu = 1.97(2); Pro = 2.1(2); Gly = 3.91(4); Ala = 1.97(2); Val = 4.88(5); He = 2.0(2); Leu = 6.87(7); Tyr = 1.11(1); Phe = 3.2(3); Lys = 0.97(1); Arg = 4.88(5); Trp = 0.96 (1) . Example 5 Ser (tBu) -Gln-Gly-Gln-Val-Gln-Pro-Gly-Ala-Arg (Pbf) -Ile-Phe- Ser (tBu) -Phe-Asp (OtBu) -Gly-Arg (Pbf) -Asp (OtBu) -Val-Leu- Arg (Pbf) -His (Trt) -Pro-Ala-Trp (Boc) -Pro-Gln-Lys (Boc) - Ser (tBu) -Val-Trp (Boc) -His (Trt) -Gly-Ser (tBu) -Asp (OtBu) -Pro- Ser(tBu) -Gly-Arg (Pbf) -Arg (Pbf) -Leu-Met -Glu (OtBu) -Ser (tBu) - Tyr (tBu) -resin. 555 mg (0.1 mmoles) of Fmoc-Tyr (tBu) -resin were suspended in 25 ml of DMF and after 2 hours they were loaded into the reaction column. Then the cycle of operations described in example 1 was repeated forty-four times, using the suitably activated Fmoc-amino acid in each run, in the order indicated in the sequence reported above. The protected resin-pentatetracontapeptide thus prepared was washed with the usual solvents (see example 1) and dried under vacuum. Yield: 808 mg. Example 6 Ser-Gln-Gly-Gln-Val -Gin-Pro-Gly-Ala-Arg- Ile-Phe-Ser-Phe- Asp-Gly-Arg-Asp-Val-Leu-Arg-His-Pro-Ala-Trp-Pro-Gln-Lys- Ser-Val -Trp-His-Gly-Ser-Asp-Pro-Ser-Gly-Arg-Arg-Leu-Met- Glu-Ser-Tyr (pentatetracontapeptide III) . 888 mg of protected resin-pentatetracontapeptide were suspended in 141 ml of TFA previously added with 7.5 ml of anisole and 1.5 ml of ethanedithiol . Then the procedure described in example 2 was followed, to obtain 98 mg of pure pentatetracontapeptide III. [a] -60.5° (c=0.06, water). Mass spectrum: molecular peak (M+l) = 5125 Da. Amino acid analysis: Asp = 3.04(3); Ser = 5.88(6); Glu = 4.91(5); Pro = 3.93(4); Gly = 5.05(5); Ala = 2.07(2); Val = 2.89(3); Met = 0.91(1); He = 0.95(1); Leu = 1.93(2); Tyr = 0.93(1); Phe = 2.11(2); Lys = 0.97(1); His = 1.89(2); Arg = 4.84(5); Trp = 2.03(2). Example 7 Cys(Trt) -Glu (OtBu) -Thr(tBu) -Trp (Boc) -Arg (Pbf) -Thr (tBu) - Glu (OtBu) -Thr (tBu) -Thr (tBu) -Gly-Ala-Thr (tBu) -Gly-Gln-Ala- Ser (tBu) -Ser (tBu) -Leu-Leu-Ser (tBu) -Gly-Arg (Pbf) -Leu-Leu- Glu(OtBu) -Gln-Lys(Boc) -Ala-Ala-Ser (tBu) -Cys (Trt) -His (Trt) - Asn-Ser(tBu) -Tyr (tBu) -He-Val-Leu-Cys (tBu) -Ile-Glu (OtBu) - Asn-Ser (tBu) -Phe-Met-Thr (tBu) -Ser (tBu) -Phe-Ser (tBu) - Lys (Boc) -resin. 770 mg (0.1 mmoles) of Fmoc-Lys (Boc) -resin were suspended in 30 ml of DMF and after 2 hours loaded into the reaction column. All the other Fmoc-amino acids were assembled in the order indicated in the sequence reported above, using for each of them the operative cycle reported in example 1. 1340 mg of protected resin-pentacontapeptide were obtained. Example 8 Cys-Glu-Thr-Trp-Arg-Thr-Glu-Thr-Thr-Gly-Ala-Thr-Gly-Gln- Ala-Ser-Ser-Leu-Leu-Ser-Gly-Arg-Leu-Leu-Glu-Gln-Lys-Ala- Ala-Ser-Cys-His-Asn-Ser-Tyr-He-Val-Leu-Cys (tBu) -Ile-Glu- Asn-Ser-Phe-Met-Thr-Ser-Phe-Ser-Lys (pentacontapeptide IV) . 1340 mg of protected resin-pentacontapeptide were treated with a mixture of 188 ml of TFA, 10 ml of anisole and 2 ml of ethanedithiol . Then the cycle of operations described in example 2 was repeated to obtain 342 mg of pentacontapeptide IV. 335 mg of said peptide were dissolved in 300 ml of 75% methanol and then added drop by drop and under stirring with a solution of 25 mg of iodine in 80 ml of 75% methanol. After reacting the mixture for 3 hours at room temperature, a 10% ascorbic acid solution was added until complete decolourization of iodine. Methanol was thoroughly evaporated off under vacuum and the remaining aqueous solution was freeze-dried. The resulting crude peptide was finally purified by semipreparative HPLC, in the conditions described above. 67 mg of pure pentacontapeptide were obtained. [α] -14.5° (c=0.2, acetic acid 80%). Mass spectrum: molecular peak (M+l) = 5502 Da. Amino acid analysis: Asp = 2.03(2); Thr = 5.87(6); Ser = 7.79(8); Glu = 6.03(6); Gly = 2.87(3); Ala = 4.04(4); Cys = 2.86(3); Val = 0.97(1); Met = 0.89(1); He = 2.11(2); Leu = 4.92(5); Tyr = 1.05(1); Phe = 2.11(2); Lys = 1.93(2); His = 1.04(1); Arg = 1.87(2); Trp = 0.93(1). The biological activity of the polypeptides of the invention is illustrated in the following Experimental Section. PHARMACOLOGICAL ASSAYS Cell lines and culture conditions The coronary venular endothelial cells (CVEC) were isolated and cultured as previously described (8) . BALB/c mouse aortic endothelial 22106 cells (MAE) were grown as previously described (9) . Bovine aortic smooth muscle cells (BASM) were isolated and grown as previously described (10) . The fibroblast NIH-3T3 and A-431 cells were obtained from American Type Culture Collection (Rockville, MD) and grown accordingly with manufacturer instructions. Cvtotoxicity The cytotoxic effect of peptides was studied by trypan blue exclusion (11) . Migration assay Cell migration was assessed in 48-well microchemotaxis chambers (NeuroProbe, Biomap, Milan, Italy) on a polycarbonate filter as previously described (12,13) . Gelatin zvmographv Conditioned media from cells exposed for 24 hr to test compounds were subjected to electrophoresis in SDS- PAGE containing 1 mg/ml gelatin as previously described (14) . Gelatinase activity was evaluated by quantitative densitometry of the bands. Proliferation studies Cell proliferation was quantified by total cell number as reported (12,13). Vascular sprouting in vitro Vascular sprouting from mouse aorta rings was assessed in three-dimensional fibrin gels preparations according to the method described by Brown et al (15) , with minor modifications. Quantitative evaluation of newly formed structures was carried out at day 3. The area covered by vascular sprouts was quantified in microscopic units (0.21 mm 2 ) . Angiogenesis in vivo: rabbit cornea assay Angiogenesis was studied in the cornea of albino rabbits as previously described (11,12,13). RESULTS Cvtotoxic effects on cultured cells Endothelial and non endothelial cell lines and among the latter tumor and non-neoplastic stromal cell lines were used. To assess cytotoxicity all cell suspensions were exposed for 30 min at 37°C to 10 and 300 ng/ml of the peptides . No significant increase of cell death was detected with the trypan blue-exclusion test. Effect on endothelial cell migration Cell migration was assessed in 48-well icro- chemotaxis chambers. All the peptides inhibited the migration induced by FGF-2 and VEGF and exhibited different potency according to the concentration. An example of the inhibitory effect exerted by the fragments at the concentration of 10 ng/ml is shown in Fig. 1A-B. Surprisingly, the endostatin peptides could induce endothelial cell migration in non stimulated cells. Effect on metalloprotease activity No modification of basal and stimulated metalloprotease activity was detected by gelatin zymography in the conditioned medium of endothelial cells treated with the endostatin peptides. Effect on cell proliferation Cell proliferation was quantified by counting the total number of cells after 48 hr treatment. Endothelial cells isolated from postcapillary venules were used to test the effect on angiogenesis. The endostatin fragments did not inhibit proliferation when tested at concentration between 1 and 1000 ng/ml, whereas the end fragments were able to inhibit cell growth induced by FGF-2 and VEGF when tested at concentrations ranging between 10 and 1000 ng/ml. The effect was more pronounced on FGF-2-induced growth. Interestingly, Fragment IV was the most potent in inhibiting endothelial cell proliferation (Fig. 1C-D) . Similar effects were obtained on all the endothelial cell lines tested (Fig. IE) . The selectivity of the peptides for endotheliu was assessed on non-endothelial cell lines of vascular and non-vascular origin and on tumor cells from various sources (murine and human) . Non-endothelial cells were not affected by the endostatin peptides (Fig.2) . Effects on in vitro angiogenesis The formation of capillary-like structures in vascular rings cultured in 3D fibrin gels was used to test angiogenesis in vitro. Fragment I and IV inhibited the spontaneous growth of capillaries and the one induced by FGF-2 and VEGF. As an example the effect of 100 ng/ml concentration of either fragment is shown (Fig. 3A) . Effect on in vivo angiogenesis The angiostatic effect of endostatin fragments in vivo was assessed in the avascular rabbit cornea assay. VEGF induced an efficient and persistent neovascularization of the corneal stroma. When VEGF was tested in the presence of endostatin fragments a consistent inhibition of angiogenesis was produced. An example of the effect exerted by Fragments I and IV at 200 ng/pellet is shown in Fig. 3B. When tested as single agents the peptides did not exhibit major pro-inflammatory properties . Comparison with recombinant full length endostatin The effect of endotstatin fragments was compared to recombinant human full length endostatin produced by Dr. M. Rehn (La Jolla Cancer Research Center, La Jolla, USA) . Surprisingly, endostatin peptides resulted more efficient than full length endostain in inhibiting angiogenesis induced by VEGF (Fig. 3B) . DESCRIPTION OF THE FIGURES Figure 1 : Effect of endostatin fragments on endothelial cell migration (A,B) and proliferation (C-E) . A,B: Fragments (10 ng/ml) were added together to the angiogenic factors (20 ng/ml each) in the lower compartments of the NeuroProbe microchemotaxis chamber. Incubation was carried out for 4 hr and migrated cells were microscopically counted in a blind manner. Data are expressed as total cell number counted/well. Numbers are means ± SEM of 6 experiments run in triplicate. C-E: Effect of endostatin fragments on endothelial cell proliferation. Endothelial cell (C,D: CVEC; E, MAE) proliferation was stimulated with FGF-2 and VEGF (20 ng/ml each) . Data are expressed as number of cells counted/well after 48 hr incubation with test substances. Numbers are means ± SEM of 6 and 2 experiments run in triplicate for CVEC and MAE, respectively. *P<0.05 vs FGF-2 and VEGF alone. (Student's t test) Figure 2 : Effect of endostatin fragments on non- endothelial cell lines. Proliferation of bovine aortic smooth muscle cells (BASM, upper panel) , murine fibroblasts (NIH-3T3, middle panel) and tumor cells (A431, lower panel) was evaluated as described in Fig. 2. Cell growth was stimulated with 5% FCS . Fragments were evaluated at the concentration of 300 ng/ml. Numbers are means ± SEM of 2 experiments run in triplicate. Figure 3 : Effect of endostatin fragments on angiogenesis in vitro (A) and in vivo (B) . A. In vitro vessel sprouting from rings of mouse aortas was induced by FGF-2 (10 ng/ml) . Fragments I and IV were used at 100 μg/ml . Data are reported as mean area occupied by tubules- like structures after 3 days from stimulation. Numbers are means of one representative experiment out of two run in triplicate. B. Effect of endostatin fragments on in vivo angiogenesis in the avascular rabbit cornea model . Endostatin fragments (200 ng) or full length endostatin (3 ug) were incorporated in the same pellet preparation together with VEGF (200 ng) . The angiogenic activity was compared to VEGF alone. Data are reported as angiogenic score during time (days) and are the means of 5 implants. CONCLUSIONS The peptides studied exert a potent and direct antiangiogenic effect in vitro and in vivo. The peptides act by selectively inhibiting endothelial cell growth and migration induced by angiogenic factors. Endostatin peptides resulted more efficient than full length endostain in inhibiting in vivo angiogenesis. REFERENCES 1. Folkman J. Angiogenesis in cancer, vascular, rheumatoid and other disease. Nature Medicine 1995; 1: 27- 31. 2. Hanahan D and Folkman J. Patterns and emerging mechanism of the angiogenic switch during tumorigenesis . Cell 1996; 86: 353-364. 3. Folkman J. Clinical applications of research on angiogenesis. N Engl J Med 1995; 333: 1757-1763.2. 4. Risau W. Mechanism of angiogenesis. Nature 1997; 386: 671-674. 5. 0' Really MS et al . Endostatin: an endogenous inhibitor of angiogenesis and tumor growth. Cell 1997; 88: 277-285. 6. Boehm T, et al . Anti angiogenic therapy of experimental cancer does not induce acquired drug resistance. Nature 1997; 390: 404-407. 7. Taddei L, et al . Inhibitory effect of full-length human endostatin on in vitro angiogenesis. Biochem Biophys Res Commun 1999; 263:340-345. 8. Schelling ME, et al . Venular endothelial cells from bovine heart. Am J Physiol 1988, 254, H1211-H1217. 9. Gualandris A, et al . Basic fibroblast growth factor overexpression in mouse endothelial cells: an autocrine model of angiogenesis and angioproliterative diseases. Cell Growth Differ, 1996, 7: 147-160. 10. Catalioto RM, et al . Roel of calcium in angiotensin II-induced prostaglandin release and DNA synthesis in rat vascular smooth muscle cells. J. cardiuovascular Pahramcol. 1996, 27: 195-200. 11. Presta M, et al . Purine analog 6-methylmercaptopurine ribose inhibits early and late phases of the angiogenesis process. Cancer Res. 1999, 59(10): 2417-2424. 12. Ziche M,et al . Nitric oxide mediates angiogenesis in vivo and endothelial cell growth and migration in vitro promoted by substance P. J Clin Invest 1994; 94, 2036- 2044. 13. Ziche M, et al . Nitric oxide-synthase lies downstream of vascular endothelial growth factor but not basic fibroblast growth factor induced angiogenesis. J. Clin. Invest. 1997; 99, 2625-2634. 14 Qian X, et al . Thrombospondin-1 modulates angiogenesis in vitro by up-regulation of matrix metalloproteinase-9 in endothelial cells. Exp Cell Res 1997, 235, 403-412. 15. Brown KJ, et al . A novel in vitro assay for human angiogenesis, Lab. Invest. 1996, 75 (4) : 539-555. 16. J. Folkman, 0. C. Haudenschild and B.R. Zetter, Proc . Natl. Acad. Sci. USA 76, 5217, 1979. M. Ziche, L. Morbidelli, S. Donnini and F. Ledda, J. Cardiovasc . Pharmacol., 26 (Suppl. 3), S284, 1995. 17. A. Dryland and R. C. Sheppard, J. Chem. Soc . , Perkin 1, 125, 1986. 18. E. Bayer, Angew. Chem., 103, 117, 1991.

Claims: CLAIMS 1. Polypeptides comprising ten to sixty amino acids with a sequence corresponding or homologous to that of endostatin, having antiangiogenic activity. 2. A polypeptide as claimed in claim 1, which is nonatriacontapeptide I, with sequence His-Thr-His-Gln-Asp- Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Thr-Pro-Leu- Ser-Gly-Gly-Met-Arg-Gly-Ile-Arg-Gly-Ala-Asp-Phe-Gln- Cys (tBu) -Phe-Gln-Gln-Ala-Arg-Ala. 3. A polypeptide as claimed in claim 1, which is pentacontapeptide II, with sequence Val-Gly-Leu-Ser-Gly- Thr-Phe-Arg-Ala-Phe-Leu-Ser-Ser-Arg-Leu-Gln-Asp-Leu-Tyr- Ser-Ile-Val-Arg-Arg-Ala-Asp-Arg-Gly-Ser-Val-Pro-Ile-Val- Asn-Leu-Lys-Asp-Glu-Val-Leu-Ser-Pro-Ser-Trp-Asp-Ser-Leu- Phe-Ser-Gly. 4. A polypeptide as claimed in claim 1, which is pentatetracontapeptide III, with sequence Ser-Gln-Gly-Gln- Val-Gln-Pro-Gly-Ala-Arg-Ile-Phe-Ser-Phe-Asp-Gly-Arg-Asp- Val-Leu-Arg-His-Pro-Ala-Trp-Pro-Gln-Lys-Ser-Val-Trp-His- Gly-Ser-Asp-Pro-Ser-Gly-Arg-Arg-Leu-Met-Glu-Ser-Tyr. 5. A polypeptide as claimed in claim 1, which is pentacontapeptide IV, with sequence Cys-Glu-Thr-Trp-Arg- Thr-Glu -Thr-Thr-Gly-Ala-Thr-Gly-Gln-Ala-Ser-Ser-Leu-Leu- Ser-Gly-Arg-Leu-Leu-Glu-Gln-Lys-Ala-Ala-Ser-Cys-His-Asn- Ser-Tyr-He-Val-Leu-Cys (tBu) -He-Glu-Asn-Ser-Phe-Met-Thr- Ser-Phe-Ser-Lys . 6. A process for the preparation of the polypeptides as claimed in claims 1-5 by solid phase synthesis. 7. A process as claimed in claim 6, characterized in that an automatic synthesizer is used. 8. Pharmaceutical formulations with antiangiogenic activity, consisting of one or more polypeptides as claimed in claims 1-5. 9. Pharmaceutical formulations with antiangiogenic activity, containing as the active ingredient one or more polypeptides as claimed in claims 1-5, optionally in combination with other active principles. 10. The use of the polypeptides as claimed in claims 1-5 for the preparation of medicaments with antiangiogenic activity.

Inventors: CHILLEMI FRANCESCO, FRANCESCATO PIERANGELO, ZICHE MARINA, CHILLEMI, FRANCESCO, FRANCESCATO, PIERANGELO, ZICHE, MARINA
Applicants: CHILLEMI FRANCESCO, FRANCESCATO PIERANGELO, UNIV FIRENZE, UNIV MILANO, ZICHE MARINA, CHILLEMI, FRANCESCO, FRANCESCATO, PIERANGELO, UNIVERSITA' DEGLI STUDI DI FIRENZE, UNIVERSITA' DEGLI STUDI DI MILANO, ZICHE, MARINA
Application year: 2000
Main classification: C07K14
IPC codes: A61K38, A61P35, A61P43, C07K7, C07K14