Pentamidine isethionate (Pentamidine diisethionate) is a synthetic amidine derivative, Pentamidine Isethionate is an antiprotozoal and antifungal agent.

Leishmania infantum:2.5 μM (IC50)

Pentamidine在实验中已知会干扰多种细胞过程。特别地，Pentamidine能以非插入方式与DNA结合，并似乎优先结合到锥虫的线粒体DNA。此外，Pentamidine可能抑制RNA聚合酶和核糖体功能，以及核酸、蛋白质、磷脂和多胺的合成。Pentamidine还能抑制包括胰蛋白酶在内的某些蛋白酶，并损害细胞的氧气消耗。[1] Pentamidine具有强效的体外抗原生动物活性，对L. infantum草履虫表现出细胞毒性活性，其半抑制浓度（IC50）为2.5 μM。2.5 μM的Pentamidine能引起49.6%的L. infantum草履虫提前进入程序性细胞死亡，并在G1和S期相对于对照组未处理样本显著减少草履虫（G1:77.0 vs 15.0%；S:11.0 vs 2.4%）。Pentamidine能与小牛胸腺DNA（CT-DNA）结合并引起DNA双螺旋的构象变化。Pentamidine还能与泛素结合，修改泛素的β-簇。[2] Pentamidine是再生肝脏磷酸酶（PRLs）的抑制剂。1 μg/mL的Pentamidine能完全抑制重组的PTP1B去磷酸化一个磷酸酪氨酸肽。10 μg/mL的Pentamidine完全抑制了重组的PRL-1、PRL-2和PRL-3去磷酸化一种磷酸酪氨酸肽底物的活性。与Pentamidine（1 μg/mL）孵育48小时，可以使转染的NIH3T3细胞中的PRL磷酸酶活性降低超过85%。10 μg/mL的Pentamidine能完全抑制表达内源性PRLs的黑色素瘤细胞系（WM9）、前列腺癌细胞系（DU145和C4-2）、卵巢癌细胞系（Hey）、结肠癌细胞系（WM480）和肺癌细胞系（A549）的增长。[3]

Pentamidine在动物模型中展现出显著的抗原虫活性。Pentamidine (0.3-9 mg/L) 降低了在鸡胚肺上皮细胞和肺炎大鼠肺细胞中实验模型的P. carinii的存活率。5 mg/kg的Pentamidine治疗2周，能在75%的动物中根除Pneumocystis carinii肺炎。[4] Pentamidine抑制了裸鼠中WM9人类黑色素瘤肿瘤的生长。在16周的研究期间，250 μg Pentamidine处理的小鼠中的肿瘤大小与治疗开始时相似，而对照组小鼠中的肿瘤增长迅速，以至于在第4周时需要对动物进行人道处死。Pentamidine诱导显著的坏死，占肿瘤质量的50%以上。[3]

In vitro PTPase assays: Individual PTPases (0.01 μg/reaction) in 50 μL of PTPase buffer [50 mM Tris (pH 7.4)] are incubated at 22 ℃ for 10 min or as indicated in the absence or presence of inhibitory compounds. Substrates (0.2 mM phosphotyrosine peptide) are then added and allows to react at 22 ℃ for 18 hr. PTPase activity of individual reactions is measured by adding 100 μL of malachite green solution (UBI) and then quantifying the amounts of free phosphate cleaved by the PTPase from the peptide substrate by spectrometry (A660 nm). Relative PTPase activities are calculated based on the formula [(PTPase activity in the presence of an inhibitory compound)/(PTPase activity in the absence of the compound) × 100%]. Reactions performed under comparable conditions in the absence of recombinant PTPases only are used as controls and shows no detectable PTPase activity.

Cells are washed in 10% FCS contained RPMI 1640 medium twice, resuspended in 10% FCS medium, incubated at 37 ℃ for 16 hr, and then cultured at 37 ℃ in 10% FCS medium containing various amounts of Pentamidine for 6 days. The cell numbers in proliferation assays are determined by an MTT assay.(Only for Reference)