Non-mammalian GnRH analogs and uses thereof in tumor cell growth regulation and cancer therapy

Abstract

Specially designed non-mammalian GnRH analogs resistant to degradation by the tumor tissue enzymes, post-proline peptidases as well as endopeptidases, are disclosed. The GnRH analogs are further defined as analogs of chicken II GnRH, salmon GnRH, or herring GnRH, but can include any non-mammalian GnRH analog with similar amino acid structure. These non-mammalian analogs incorporate D-arginine, D-leucine, D-tBu-Serine or D-Trp or other similar amino acids at position 6 and ethylamide or aza-Gly-amide or similar amides at position 10. These analogs demonstrate preferential binding to tumor cell GnRH receptors that is greater relative to the binding of the mammalian analogs to the tumor cell GnRH receptor. These non-mammalian GnRH analogs may be used in pharmaceutical preparations, and specifically in various treatments as an anti-tumor, anti-proliferation, anti-metastatic and/or an apoptotic agent. The non-mammalian GnRH analogs are also provided in pharmaceutical preparations that may be used clinically for tumor regression when used in very low doses and administered in pulsatile fashion.

We claim:  
     
         1 . A Chicken II GnRH analog, having the sequence p-Glu-His-Trp-Ser-His-Xaa1-Trp-Tyr-Pro-Xaa2 wherein said analog is capable of binding to tumor cell GnRH receptors with greater affinity than mammalian GnRH and is active in the presence of a post-proline peptidase or endopeptidase.  
     
     
         2 . The Chicken II GnRH analog of  claim 1  wherein said Chicken II GnRH analog has a D-amino acid substitution at position 6 and a post-proline peptidase inhibitor at position 10.  
     
     
         3 . The Chicken II GnRH analog of  claim 2  wherein said post-proline peptidase inhibitor is selected from the group consisting of aza-Gly-amide or ethylamide.  
     
     
         4 . The Chicken II GnRH analog of  claim 2  wherein said Chicken II GnRH analog is further defined as an anti-tumor agent.  
     
     
         5 . The Chicken II GnRH analog of  claim 2  wherein said Chicken II GnRH analog is further defined as an anti-proliferative agent.  
     
     
         6 . The Chicken II GnRH analog of  claim 5  wherein said Chicken II GnRH analog is further defined as an anti-metastatic agent.  
     
     
         7 . The Chicken II GnRH analog of  claim 6  wherein said Chicken II GnRH analog is further defined as an apoptotic agent.  
     
     
         8 . The Chicken II GnRH analog of  claim 3  wherein said Chicken II GnRH analog is selected from the group consisting of D-Arg (6)-Chicken II GnRH-ethylamide and D-Arg (6)-Chicken II GnRH-aza-Gly (10) amide.  
     
     
         9 . A Salmon GnRH analog, having the sequence p-Glu-His-Trp-Ser-Tyr-Xaa1-Trp-Leu-Pro-Xaa2, wherein said analog is capable of binding to tumor cell GnRH receptors with greater affinity than mammalian GnRH and is active in the presence of a post-proline peptidase or endopeptidase.  
     
     
         10 . The Salmon GnRH analog of  claim 9  wherein said Salmon GnRH analog has a D-amino acid substitution at position 6 and a post-proline peptidase inhibitor at position 10.  
     
     
         11 . The Salmon GnRH analog of  claim 10  wherein said post-proline peptidase inhibitor is selected from the group consisting of aza-Gly-amide or ethylamide.  
     
     
         12 . The Chicken II GnRH analog of  claim 8  having a sequence as defined in SEQ ID NO: 2.  
     
     
         13 . The Chicken II GnRH analog of  claim 2  wherein said Chicken II GnRH has a cDNA sequence of SEQ ID NO: 1.  
     
     
         14 . The Salmon GnRH analog of  claim 11  having a sequence as defined in SEQ ID NO: 4.  
     
     
         15 . The composition of  claim 11  wherein said Salmon GnRH has a cDNA sequence of SEQ ID NO: 3.  
     
     
         16 . A Herring GnRH analog, having the sequence p-Glu-His-Trp-Ser-Tyr-Xaa1-Leu-Ser-Pro-Xaa2, wherein said analog is capable of binding to tumor cell GnRH receptors with greater affinity than mammalian GnRH and is active in the presence of a post-proline peptidase or endopeptidase.  
     
     
         17 . The Herring GnRH analog of  claim 16  wherein said Herring GnRH analog has a D-amino acid substitution at position 6 and a post-proline peptidase inhibitor at position 10.  
     
     
         18 . The Herring GnRH analog of  claim 17  wherein said post-proline peptidase inhibitor is selected from the group consisting of aza-Gly-amide or ethylamide.  
     
     
         19 . The Herring GnRH analog of  claim 17  having a sequence as defined in SEQ ID NO: 6.  
     
     
         20 . A method for regulating tumor activity using a non-mammalian GnRH analog comprising the step of administering to a mammal a pharmaceutical preparation of the analog, wherein said analog is capable of binding to tumor GnRH receptors with greater affinity than mammalian GnRH and is active in the presence of a post-proline peptidase or endopeptidase due to a D-amino acid substitution at position 6 and a post-proline peptidase inhibitor at position 10.  
     
     
         21 . The method of  claim 20  wherein said non-mammalian GnRH analog is selected from the group consisting of Chicken II GnRH analog, Salmon GnRH analog, and Herring GnRH analog.  
     
     
         22 . The method of  claim 21  wherein said Chicken II GnRH analog is selected from the group consisting of D-Arg(6)-Chicken II GnRH-ethylamide and D-Arg(6)-Chicken II GnRH-aza-Gly(10)-amide.  
     
     
         23 . The method of  claim 22  wherein said Salmon GnRH analog is selected from the group consisting of D-Arg(6)-Salmon-GnRH-ethylamide and D-Arg(6)-Salmon-GnRH-aza-Gly(10)-amide.