One of the potent somatostatin analogs, BIM-23052 (DC-23-99) d-Phe-Phe-Phe-d-Trp-Lys-Thr-Phe-Thr-NH₂, has established in vitro growth hormone inhibitory activity in nM concentrations. It is also characterized by high affinity to some somatostatin receptors which are largely distributed in the cell membranes of many tumor cells. Herein, we report the synthesis of a series of analogs of BIM-23052 containing halogenated Phe residues using standard solid-phase peptide method Fmoc/OtBu-strategy. The cytotoxic effects of the compounds were tested in vitro against two human tumor cell lines—breast cancer cell line and hepatocellular cancer cell line, as well as on human non-tumorigenic epithelial cell line. Analogs containing fluoro-phenylalanines are cytotoxic in μM range, as the analog containing Phe (2-F) showed better selectivity against human hepatocellular cancer cell line. The presented study also reveals that accumulation of halogenated Phe residues does not increase the cytotoxicity according to tested cell lines. The calculated selective index reveals different mechanisms of antitumor activity of the parent compound BIM-23052 and target halogenated analogs for examined breast tumor cell lines. All peptides tested have high antitumor activity against the HepG2 cell line (IC₅₀ ≈ 100 μM and SI > 5) compared to breast cells. This is probably due to the high permeability of the cell membrane and the higher metabolic activity of hepatocytes. In silico docking studies confirmed that all obtained analogs bind well with the somatostatin receptors with preference to ssrt3 and ssrt5. All target compounds showed high hydrolytic stability at acid and neutral pH, which mimic physiological condition in stomach and human plasma.

一种有效的生长抑素类似物，BIM-23052 (DC-23-99) d -Phe-Phe-Phe- d -Trp-Lys-Thr-Phe-Thr-NH ₂, 已在 nM 浓度下建立了体外生长激素抑制活性。它还具有对一些生长抑素受体的高亲和力的特点，这些受体主要分布在许多肿瘤细胞的细胞膜中。在此，我们报告了使用标准固相肽法 Fmoc/OtBu-strategy 合成一系列含有卤化 Phe 残基的 BIM-23052 类似物。在体外针对两种人类肿瘤细胞系（乳腺癌细胞系和肝细胞癌细胞系）以及人类非致瘤性上皮细胞系测试了这些化合物的细胞毒性作用。含有氟苯丙氨酸的类似物在 μM 范围内具有细胞毒性，因为含有 Phe (2-F) 的类似物对人肝细胞癌细胞系显示出更好的选择性。所提出的研究还表明，根据测试的细胞系，卤化 Phe 残基的积累不会增加细胞毒性。计算出的选择性指数揭示了母体化合物 BIM-23052 和目标卤化类似物对于检查的乳腺肿瘤细胞系的不同抗肿瘤活性机制。所有测试的肽对 HepG2 细胞系 (IC与乳腺细胞相比，₅₀ ≈ 100 μM 且 SI > 5)。这可能是由于细胞膜的高渗透性和肝细胞更高的代谢活性。计算机对接研究证实，所有获得的类似物与生长抑素受体结合良好，优先于 ssrt3 和 ssrt5。所有目标化合物在酸性和中性 pH 值下均表现出高水解稳定性，模拟胃和人体血浆中的生理条件。