Anti-Cancer Activities of PTPase Inhibitors

描述（由申请人提供）：蛋白酪氨酸磷酸酶（PTPases）是关键信号分子，也是开发抑制剂作为新型治疗剂的潜在靶点。我们的初步研究首次证明，葡萄糖酸锑钠（SS）和葡聚糖时间（GT），锑（Sb）为基础的抗利什曼原虫药物的未知机制，是选择性PTPases抑制剂，在体外和小鼠模型中，在无毒剂量和协同干扰素对癌细胞的活性。我们提出以下具体目标：目标1。为了检验SS抗癌活性通过使PRL和SHP失活而起作用的假设，我们将：a）使用SS不敏感的PRL突变体评估PRL在SS对癌细胞系的活性中的作用; B）使用SHP缺陷的细胞系和SHP转染子评估SHP在SS与IFN α协同作用中在细胞生长抑制中的作用; c）确定SS在小鼠模型中抑制PRL/SHP的药效学; d）确定SS对癌细胞中PRL调节的信号传导分子的作用; e）确定SS对WM 9黑素瘤细胞中IFN α信号传导分子的作用，SS和IFN α对WM 9黑素瘤细胞显示协同作用。目标二。为了检验SS通过药物中的Sb共价修饰酶中的催化半胱氨酸残基而使靶PTPases失活，而与Sb缀合的葡萄糖酸促进Sb/半胱氨酸相互作用并确定药物的PTPases特异性的假设，我们将：a）通过质谱和突变分析确定SS诱导的PRL-2质量增加的性质和意义; B）评估SS修饰对SS抑制不敏感的MKP 1和PRL-1 R86突变体的能力; d）测定SS不同分子量级分的PTB抑制活性和抗癌活性，其是100-4000 Da的Sb/葡萄糖酸络合物的聚合物的混合物。为了检验GT通过靶向PTPases具有抗癌活性的假设，我们将：a）确定其对一组PTPases的抑制活性; B）通过质谱和突变分析确定其抑制机制; c）在体外和小鼠模型中评估其对人癌细胞系的抗癌活性; d）评估其靶PTPases在介导其抗癌活性中的作用。

DESCRIPTION (provided by applicant): Protein tyrosine phosphatases (PTPases) are key signaling molecules and potential targets for developing inhibitors as novel therapeutics. Our preliminary studies demonstrate for the first time that sodium stibogluconate (SS) and glucantime (GT), antimony (Sb) based anti-leishmania drugs of unknown mechanism, are inhibitors of selective PTPases with activity against cancer cells in vitro and in mouse models at nontoxic doses and in synergy with IFNs. We propose the following specific aims: Aim 1. To test the hypothesis that SS anti-cancer activity functions via inactivating PRLs and SHPs, we will: a), assess the role of PRLs in SS activity against cancer cell lines using SS-insensitive PRL mutants; b), assess the role of SHPs in SS synergy with IFNa in cell growth inhibition using SHP-deficient cell lines and SHP transfectants; c), define the pharmacodynamics of SS in inhibiting PRLs/SHPs in mouse models; d), determine the effects of SS on PRLs-regulated signaling molecules in cancer cells; e), determine the effects of SS on IFNa signaling molecules in WM9 melanoma cells against which SS and IFNa showed a synergistic effect. Aim 2. To test the hypothesis that SS inactivates target PTPases via covalent modification of a catalytic cysteine residue in the enzymes through the Sb in the drugs while the gluconic acid conjugated to Sb facilitates Sb/cysteine interactions and defines the drugs' PTPase specificity, we will: a), define the nature and significance of SS-induced mass increase in PRL-2 by mass spectrometry and mutational analysis; b), assess the ability of SS to modify MKP1 and PRL-1R86 mutant insensitive to SS inhibition; c), determine the effects of Sb and gluconic acid on PTPases sensitive or insensitive to SS inhibition; d), determine the PTPase inhibitory activity and anti-cancer activity of different molecular weight fractions of SS, which is mixture of polymers of Sb/gluconic acid complexes of 100-4000 Da. Aim 3. To test the hypothesis that GT has anti-cancer activity via targeting PTPases, we will: a), determine its inhibitory activity against a panel of PTPases; b), define its inhibitory mechanism by mass spectrometry and mutational analysis; c), assess its anti-cancer activity against human cancer cell lines in vitro and in mouse models; d), assess the role of its target PTPases in mediating its anti-cancer activity.