Amblard M, Rodriguez M, Lignon M F, Galas M C, Bernad N, Artis-Noël A M, Hauad L, Laur J, Califano J C, Aumelas A
EP CNRS 51, Faculté de Pharmacie, Montpellier, France.
J Med Chem. 1993 Oct 1;36(20):3021-8. doi: 10.1021/jm00072a024.
Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester (JMV180), an analog of the C-terminal octapeptide of cholecystokinin (CCK-8), shows interesting biological activities behaving as an agonist at the high-affinity CCK binding sites and as an antagonist at the low-affinity CCK binding sites in rat pancreatic acini. Although we did not observe any major hydrolysis of the ester bond of Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester in our in vitro studies, we were aware of a possible and rapid cleavage of this ester bond during in vivo studies. To improve the stability of Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester, we decided to synthesize analogs in which the ester bond would be replaced by a carba (CH2-CH2) linkage. We synthesized the 3-amino-7-phenylheptanoic acid (beta-homo-Aph) with the R configuration in order to mimic the Asp-2-phenylethyl ester moiety and the 3-amino-6-(phenyloxy)hexanoic acid (H-beta-homo-App-OH), an analog of H-beta-homo-Aph-OH in which a methylene group has been replaced by an oxygen. (R)-beta-Homo-Aph and (R)-H-beta-homo-App-OH were introduced in the CCK-8 sequence to produce Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-(R)-beta-homo-Aph-OH and Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-(R)-beta-homo-App-OH. Both compounds were able to recognize the CCK receptor on rat pancreatic acini (IC50 = 12 +/- 8 nM and 13 +/- 5 nM, respectively), on brain membranes (IC50 = 32 +/- 2 nM and 57 +/- 5 nM, respectively), and on Jurkat T cells (IC50 = 75 +/- 15 nM and 65 +/- 21 nM, respectively). Like Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester, both compounds produced maximal stimulation of amylase secretion (EC50 = 6 +/- 2 nM and 4 +/- 2 nM, respectively) with no decrease of the secretion at high concentration indicating that these compounds probably act as agonists at the high-affinity peripheral CCK-receptor and as antagonists at the low-affinity CCK-receptor. Replacing the tryptophan by a D-tryptophan in such analogs produced full CCK-receptor antagonists. All these analogs might be more suitable for in vivo studies than Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester.
Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-苯乙酯（JMV180）是胆囊收缩素C末端八肽（CCK-8）的类似物，具有有趣的生物学活性，在大鼠胰腺腺泡中，它在高亲和力CCK结合位点表现为激动剂，在低亲和力CCK结合位点表现为拮抗剂。尽管我们在体外研究中未观察到Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-苯乙酯的酯键有任何明显水解，但我们意识到在体内研究过程中该酯键可能会迅速断裂。为提高Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-苯乙酯的稳定性，我们决定合成酯键被碳桥（CH2-CH2）连接取代的类似物。我们合成了具有R构型的3-氨基-7-苯基庚酸（β-高同型Aph）以模拟Asp-2-苯乙酯部分，并合成了3-氨基-6-（苯氧基）己酸（H-β-高同型App-OH），它是H-β-高同型Aph-OH的类似物，其中一个亚甲基被氧取代。将（R）-β-高同型Aph和（R）-H-β-高同型App-OH引入CCK-8序列中，得到Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-（R）-β-高同型Aph-OH和Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-（R）-β-高同型App-OH。这两种化合物都能够识别大鼠胰腺腺泡上的CCK受体（IC50分别为12±8 nM和13±5 nM）、脑膜上的CCK受体（IC50分别为32±2 nM和57±5 nM）以及Jurkat T细胞上的CCK受体（IC50分别为75±15 nM和65±21 nM）。与Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-苯乙酯一样，这两种化合物都能产生淀粉酶分泌的最大刺激（EC50分别为6±2 nM和4±2 nM），且在高浓度时分泌不减少，这表明这些化合物可能在高亲和力外周CCK受体处作为激动剂，在低亲和力CCK受体处作为拮抗剂。在这类类似物中用D-色氨酸取代色氨酸可产生完全的CCK受体拮抗剂。所有这些类似物可能比Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-苯乙酯更适合用于体内研究。
