Methods for inhibiting tumor cell proliferation

A method for inhibiting tumor cell proliferation, consisting of administering to a patient with a tumor an amount effective for inhibiting tumor cell proliferation of at least one active agent comprising a sequence of at least three contiguous amino acids of groups R1-R8 in the sequence of general formula I

• R1-R2-R3R4 -R5-R6-R7-R8
• wherein R1 is selected from the group consisting of H, Asp, Glu, Asn, Acpc (1-aminocyclopentane carboxylic acid), Ala, Me2Gly, Pro, Bet, Glu(NH2), Gly, Asp(NH2) and Suc,
• R2 is selected from the group consisting of Arg, Lys, Ala, Orn, Ser(Ac), Sar, D-Arg and D-Lys;
• R3 is selected from the group consisting of Val, Ala, Leu, Lys, norLeu, Ile, Gly, Pro, Aib, Acpc and Tyr;
• R4 is selected from the group consisting of Tyr, Tyr(PO3)2, Thr, Ser, Ala, homoSer and azaTyr;
• R5 is selected from the group consisting of Ile, Ala, Leu, norLeu, Val and Gly;
• R6 is selected from the group consisting of His, Arg and 6-NH2-Phe;
• R7 is selected from the group consisting of Pro and Ala;
• and
• R8 is selected from the group consisting of Phe, Phe(Br), Ile and Tyr,
• excluding sequences including R4 as an N-terminal Tyr group;
• and wherein the active agent is not SEQ ID NO:1.