Conformationally constrained backbone cyclized somatostatin analogs

1. A method for treating disorders selected from the group consisting of cancers, diabetes, diabetic-associated complications, endocrine disorders, gastrointestinal disorders, and pancreatitis, comprising administering to a mammal having one of such disorders and in need of treatment thereof a pharmaceutical composition that includes a therapeutically effective amount of a backbone cyclized somatostatin analog comprising a peptide sequence of four to twelve amino acids that incorporates at least one building unit, said building unit containing one nitrogen atom of the peptide backbone connected to a bridging group comprising an amide, thioether, thioester, or disulfide, wherein the at least one building unit is connected via the bridging group to form a cyclic structure with a moiety selected from the group consisting of a second building unit, the side chain of an amino acid residue of the sequence or the N-terminal amino acid residue, wherein the sequence includes a non-cyclized chain of 4, 5 or 6 amino acids.

2. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is selective for one somatostatin receptor subtype.

3. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is selective for two somatostatin receptor subtypes.

4. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 7:

wherein

n is 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

Q is hydrogen or a mono- or di-saccharide;

R 5 is gamma amino butyric acid, diamino butyric acid, Gly, α-Ala, 5-amino pentanoic acid or amino hexanoic acid;

R 6 is (D)- or (L)-(Phe) or Tyr;

R 7 is (D)- or (L)-Trp, (D)- or (L)-Phe, (D)- or (L)-1Nal, (D)- or (L)-2Nal, or Tyr;

R 8 is (D)- or (L)-Trp;

R 9 is (D)- or (L)-Lys;

R 10 is Thr, Gly, Abu, Ser, Cys, Val, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 11 is (D)- or (L)-Phe, (D)- or (L)-Ala, Nle, or Cys;

R 12 is Gly, Val, Leu, (D)- or (L)-Phe, 1Nal, or 2Nal; and

Y is amide, thioether, thioester or disulfide.

5. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 8:

wherein:

m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 6 is (D)- or (L)-Phe, or (D)- or (L)-Ala;

R 7 is Tyr, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 10 is Thr, Val, Ser, or Cys;

R 11 is Val, (D)- or (L)-1Nal, (D)- or (L)-2Nal, or (D) or (L)-Phe;

R 12 is Gly, (D)- or (L)-Ala, or (D) or (L)-Phe; and

Y is amide, thioether, thioester or disulfide.

6. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 9:

wherein:

m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 6 is (D)- or (L)-Phe, or (D)- or (L)-Ala;

R 7 is Tyr or (D)- or (L)-Phe;

R 8 is (D)- or (L)-Trp, (D)- or (L)-1Nal, or (D)- or (L)-2Nal;

R 10 is Thr, Vat, Ser, or Cys;

R 11 is Gly or (D) or (L)-Phe;

R 12 is Thr, GABA, (D)- or (L)-1Nal, (D)- or (L)-2Nal, or (D) or (L)-Phe; and

Y is amide, thioether, thioester or disulfide.

7. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 13:

wherein m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 6 is (D)- or (L)-Phe or Tyr;

R 7 is (D)- or (L)-Trp, (D)- or (L)-Phe, (D)- or (L)-1Nal or (D)- or (L)-2Nal, or Tyr;

R 10 is Thr, Gly, Abu, Ser, Cys, Val, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 11 is (D)- or (L)-Phe or (D)- or (L)-Ala;

R 12 is Gly, Val, or (D)- or (L)-Phe; and

Y is thioether, thioester or disulfide.

8. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 14:

wherein

m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 4 is (D)- or (L)-Phe or Tyr;

R 6 is (D)- or (L)-Phe or Tyr;

R 7 is (D)- or (L)-Trp, (D)- or (L)-Phe, (D)- or (L)-1Nal or (D)- or (L)-2Nal, or Tyr;

R 10 is Thr, Gly, Abu, Ser, Cys, Val, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 11 is (D)- or (L)-Phe or (D)- or (L)-Ala;

R 12 is Gly, Val, or (D)- or (L)-Phe; and

Y is thioether, thioester or disulfide.

9. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 15:

wherein

m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 5 is (D)- or (L)-Phe or (D)- or (L)-Ala;

R 7 is (D)- or (L)-Trp, (D)- or (L)-Phe, (D)- or (L)-1Nal or (D)- or (L)-2Nal, or Tyr;

R 10 is Thr, Gly, Abu, Ser, Cys, Val, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 12 is Gly, Val, or (D)- or (L)-Phe, or is absent;

R 13 is (D)- or (L)-Phe or (D)- or (L)-Ala; and

Y is amide, thioether, thioester or disulfide.

10. The method according to claim 1 , wherein the backbone cyclized somatostatin analog is

Phe(N2)-Tyr-(D)2Nal-Lys-Val-Gly(C2)-Thr-X;

Phe(N2)-Tyr-(D)Trp-Lys-Val-Gly(C2)-2Nal-X;

Phe(N2)-Tyr-(D)Trp-Lys-Val-Val-Gly(C2)-X;

Phe(N2)-Tyr-(D)Trp-Lys-Ser-2Nal-Gly(C2)-X;

Phe(N2)-Phe-(D)Trp-Lys-Thr-2Nal-Gly(C2)-X;

GABA*-Phe-Trp-(D)Trp-Lys-Thr-P-The-Gly(C3)-X;

Cys*-Phe-Trp-(D)Trp-Lys-Thr-Phe-Gly(S2)-X;

Phe(C3)-Cys*-Phe-(D)Trp-Lys-Thr-Cys*-Phe(N3)-X;

(D)Phe-Cys*-Phe-Trp-(D)Trp-Lys-Thr-Phe-Gly(S2)-X; or

Galactose-Dab*-Phe-Trp-(D)Trp-Lys-Thr-Phe-Gly(C3)-X;

wherein X designates a terminal carboxy acid, amide, or alcohol group; the asterisk denotes that the bridging group is connected between the N α -ω-functionalized derivative of an amino acid and the N-terminus of the peptide or the side chain of the Cys residue.

11. A method for diagnosing cancer comprising administration of a backbone cyclized somatostatin analog to a mammal in an amount effective to identify cancer in the mammal, with the analog comprising a peptide sequence of four to twelve amino acids that incorporates at least one building unit, said building unit containing one nitrogen atom of the peptide backbone connected to a bridging group comprising an amide, thioether, thioester, or disulfide, wherein the at least one building unit is connected via the bridging group to form a cyclic structure with a moiety selected from the group consisting of a second building unit, the side chain of an amino acid residue of the sequence or the N-terminal amino acid residue, wherein the sequence includes a non-cyclized chain of 4, 5 or 6 amino acids.

12. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is used for imaging the existence of metastases.

13. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is labeled with a detectable probe.

14. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 7:

general formula 7:

wherein

n is 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

Q is hydrogen or a mono- or di-saccharide;

R 5 is gamma amino butyric acid, diamino butyric acid, Gly, α-Ala, 5-amino pentanoic acid or amino hexanoic acid;

R 6 is (D)- or (L)-Phe or Tyr;

R 7 is (D)- or (L)-Trp, (D)- or (L)-Phe, (D)- or (L)-1Nal, (D)- or (L)-2Nal, or Tyr;

R 8 is (D)- or (L)-Trp;

R 9 is (D)- or (L)-Lys;

R 10 is Thr, Gly, Abu, Ser, Cys, Val, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 11 is (D)- or (L)-Phe, (D)- or (L)-Ala, Nle, or Cys;

R 12 is Gly, Val, Leu, (D)- or (L)-Phe, 1Nal, or 2Nal; and

Y is amide, thioether, thioester or disulfide.

15. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 8:

wherein:

m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 6 is (D)- or (L)-Phe, or (D)- or (L)-Ala;

R 7 is Tyr, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 10 is Thr, Val, Ser, or Cys;

R 11 is Val, (D)- or (L)-1Nal, (D)- or (L)-2Nal, or (D) or (L)-Phe;

R 12 is Gly, (D)- or (L)-Ala, or (D) or (L)-Phe; and

Y is amide, thioether, thioester or disulfide.

16. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 9:

wherein:

m and n are 1 to5;

X designates a terminal carboxy acid, amide or alcohol group; R 6 is (D)- or (L)-Phe, or (D)- or (L)-Ala;

R 7 is Tyr or (D)- or (L)-Phe;

R 8 is (D)- or (L)-Trp, (D)- or (L)-1Nal, or (D)- or (L)-2Nal;

R 10 is Thr, Val, Ser, or Cys; R 11 is Gly or (D) or (L)-Phe; R 12 is Thr, GABA, (D)- or (L)-1Nal, (D)- or (L)-2Nal, or (D) or (L)-Phe; and

Y is amide, thioether, thioester or disulfide.

17. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 13:

wherein m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 6 is (D)- or (L)-Phe or Tyr;

R 7 is (D)- or (L)-Trp, (D)- or (L)-Phe, (D)- or (L)-1Nal or (D)- or (L)-2Nal, or Tyr;

R 10 is Thr, Gly, Abu, Ser, Cys, Val, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 11 is (D)- or (L)-Phe or (D)- or (L)-Ala;

R 12 is Gly, Val, or (D)- or (L)-Phe; and

Y is thioether, thioester or disulfide.

18. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 14:

wherein

m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 4 is (D)- or (L)-Phe or Tyr;

R 6 is (D)- or (L)-Phe or Tyr;

R 7 is (D)- or (L)-Trp, (D)- or (L)-Phe, (D)- or (L)-1Nal or (D)- or (L)-2Nal, or Tyr;

R 10 is Thr, Gly, Abu, Ser, Cys, Val, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 11 is (D)- or (L)-Phe or (D)- or (L)-Ala;

R 12 is Gly, Val, or (D)- or (L)-Phe; and

Y is thioether, thioester or disulfide.

19. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is represented by the structure of the general formula 15:

wherein

m and n are 1 to 5;

X designates a terminal carboxy acid, amide or alcohol group;

R 5 is (D)- or (L)-Phe or (D)- or (L)-Ala;

R 7 is (D)- or (L)-Trp,(D)- or (L)-Phe, (D)- or (L)-1Nal or (D)- or (L)-2Nal, or Tyr;

R 10 is Thr, Gly, Abu, Ser, Cys, Val, (D)- or (L)-Ala, or (D)- or (L)-Phe;

R 12 is Gly, Val, or (D)- or (L)-Phe, or is absent;

R 13 is (D)- or (L)-Phe or (D)- or (L)-Ala; and

Y is amide, thioether, thioester or disulfide.

20. The method according to claim 11 , wherein the backbone cyclized somatostatin analog is

Phe(N2)-Tyr-(D)2Nal-Lys-Val-Gly(C2)-Thr-X;

Phe(N2)-Tyr-(D)Trp-Lys-Val-Gly(C2)-2Nal-X;

Phe(N2)-Tyr-(D)Trp-Lys-Val-Val-Gly(C2)-X;

Phe(N2)-Tyr-(D)Trp-Lys-Ser-2Nal-Gly(C2)-X;

Phe(N2)-Phe-(D)Trp-Lys-Thr-2Nal-Gly(C2)-X;

GABA*-Phe-Trp-(D)Trp-Lys-Thr-P-The-Gly(C3)-X;

Cys*-Phe-Trp-(D)Trp-Lys-Thr-Phe-Gly(S2)-X;

Phe(C3)-Cys*-Phe-(D)Trp-Lys-Thr-Cys*-Phe(N3)-X;

(D)Phe-Cys*-Phe-Trp-(D)Trp-Lys-Thr-Phe-Gly(S2)-X; or

Galactose-Dab*-Phe-Trp-(D)Trp-Lys-Thr-Phe-Gly(C3)-X;

wherein X designates a terminal carboxy acid, amide, or alcohol group; the asterisk denotes that the bridging group is connected between the N α -ω-functionalized derivative of an amino acid and the N-terminus of the peptide or the side chain of the Cys residue.

21. The method according to claim 1 , wherein the diabetes is Non Insulin Dependent Diabetes Mellitus (NIDDM).

22. A method of identifying a potential carcinoid drug, comprising

contacting a cancer cell with a backbone cyclized somatostatin analog comprising a peptide sequence of four to twelve amino acids that incorporates at least one building unit, said building unit containing one nitrogen atom of the peptide backbone connected to a bridging group comprising an amide, thioether, thioester, or disulfide, wherein the at least one building unit is connected via the bridging group to form a cyclic structure with a moiety selected from the group consisting of a second building unit, the side chain of an amino acid residue of the sequence or the N-terminal amino acid residue, wherein the sequence includes a non-cyclized chain of 4, 5 or 6 amino acids; and

measuring a change in the level or activity of a cellular target.

23. The method of claim 22 , comprising measuring cell growth, level of cyclic adenosine monophosphate (cAMP), growth hormone and chromogranin A secretion; or tyrosine phosphatase activity.