Stat3 Probes that Target Breast Cancer Stem Cells

针对乳腺癌干细胞的 Stat3 探针

• 批准号: 8074424
• 负责人: David John Tweardy
• 金额: $ 16.19万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8074424
• 关键词: 3-Dimensional; Affinity; Amides; Binding; Binding Sites; Biological; Biological Assay; Breast Cancer Cell; Breast Cancer Treatment; CD44 gene; Cancer Patient; Cancer Relapse; Cell Survival; Cells; Chemicals; Chloride Ion; Chlorides; Clinical Trials; Data; Data Set; Docking; Failure; Fluorescence Microscopy; Future; Gene Expression; Generations; Goals; Growth; Human; Immunocompromised Host; In Vitro; Inhibitory Concentration 50; Interferons; Interleukin-6; Lead; Libraries; Life; Ligands; Measurable; Modification; Nuclear Translocation; Parents; Pathway interactions; Patients; Peptides; Pharmaceutical Chemistry; Pharmaceutical Preparations; Phosphopeptides; Phosphorylation; Phosphotyrosine; Population; Recurrent disease; Relapse; Research Design; Residual Cancers; Residual Tumors; Resistance; Role; SCID Beige Mouse; Sampling; Screening procedure; Signal Transduction; Site; Stem cells; Structure; Structure-Activity Relationship; Surface Plasmon Resonance; Testing; Time; Transplantation; Tumorigenicity; Xenograft Model; Xenograft procedure; base; cancer stem cell; cancer therapy; chemotherapy; conventional therapy; daughter cell; design; improved; in vivo; inhibitor/antagonist; malignant breast neoplasm; novel; pharmacophore; pre-clinical; preclinical study; prevent; public health relevance; scaffold; self-renewal; small molecule; src Homology Region 2 Domain; therapy resistant; tumor; tumor growth; tumorigenic; virtual

DESCRIPTION (provided by applicant): Conventional chemotherapy is effective initially in controlling and reversing tumor growth. However, residual cancers will invariably re-grow. Our recent data from paired human breast cancer samples indicates that standard therapy eliminates dividing daughter cells while enriching the residual tumor for CD44?/low putative breast "cancer stem cells" (CSCs) that have the ability to self-renew in mammosphere (MS) cultures, and to give rise to tumors upon xenograft transplantation. We have identified a cancer stem cell signature within these CD44?/low, MS-forming cells that features Stat3. Using virtual ligand screening (VLS), we developed lead chemical probes that target the Src homology (SH) 2 domain of Stat3 and that competitively and selectively inhibited Stat3 activation. 3-D pharmacophore analysis was performed using the most active lead compound (Cpd188) and a Life Chemicals compound library; the top scoring compounds identified were tested for inhibition of Stat3 binding to its phosphopeptide ligand by surface plasmon resonance (SPR). All but six of 39 compounds tested have measurable IC50s, with 17 having IC50 values equal to or less than Cpd188. One compound (Cpd188-15) has an IC50 value in MS formation inhibition assays that is one log lower than Cpd188. We have developed 2 highly focused SPECIFIC AIMS to directly test the hypothesis that small- molecule inhibitors of Stat3 can specifically target breast cancer stem cells. AIM 1. To develop third (3rd) generation Stat3 chemical probes with increased binding affinity and inhibitory activity. We propose using the most active 2nd generation probe, Cpd188-15, as a scaffold for making 3rd generation probes. Modifications planned are based on the results of a structure-activity relationship (SAR) analysis performed on 2nd generation probes and center around the straightforward synthesis of sulfamides from panels of sulfonyl chlorides and amides. Each novel sulfamide compound will be examined in the SPR assay, in a high throughput fluorescence microscopy (HTFM) assay that will test inhibition of IL-6-stimulated cytoplasmic-to-nuclear translocation and for their selectivity for Stat3 vs. Stat1. AIM 2. To determine whether suppression of the Stat3 pathway can improve existing cancer therapies in preclinical MS assays and human xenograft models. We will determine whether Stat3 inhibition by the most active 3rd generation probes will improve efficacy of conventional therapy in vitro and in vivo, using MS formation inhibition assays and human breast cancer xenograft models. In addition to establishing the contribution of Stat3 to breast cancer stem cell survival and self-renewal, these preclinical studies may inform the design of future clinical trials and determine whether suppressing stem cell self-renewal and treatment resistance pathways can improve existing breast cancer therapies in patients. PUBLIC HEALTH RELEVANCE: A small proportion of breast cancer cells fail to respond to the usual treatments and cause relapsing disease. This proposal outlines chemical and biological studies designed to develop small molecule probes that target these therapy-resistant cells. If these studies are successful, these small molecule probes may be combined with current treatments for breast cancer thereby preventing cancer relapse and resulting in a cure.

描述（由申请人提供）：常规化疗最初是有效控制和逆转肿瘤生长的。但是，残留的癌症总是会重新生长。我们来自配对的人类乳腺癌样品的最新数据表明，标准治疗消除了分裂的女性细胞，同时富集了CD44的残留肿瘤？/低假定的乳腺癌“癌症干细胞”（CSC），具有在乳腺波（MS）培养物中自我更新的能力，并在Xenogragrapt移植上引起肿瘤。我们已经确定了这些CD44中的癌症干细胞特征？/具有STAT3的低MS形成细胞。使用虚拟配体筛选（VLS），我们开发了针对SRC同源性（SH）2 STAT3域的铅化学探针，并具有竞争性和选择性地抑制STAT3激活。使用最活跃的铅化合物（CPD188）和Life Chemicals化合物库进行3-D药效团分析。通过表面等离子体共振（SPR）测试了确定的最高评分化合物，以抑制STAT3与其磷酸肽配体的结合。除39种测试化合物中的6种外，所有除6种具有可测量的IC50，其中17个具有等于或小于CPD188的IC50值。一种化合物（CPD188-15）在MS形成抑制测定中具有IC50值，该测定比CPD188低一个。我们已经开发了2个高度关注的特定目的，以直接检验STAT3的小分子抑制剂可以特异性靶向乳腺癌干细胞的假设。 目的1。要开发具有增加结合亲和力和抑制活性的第三（第三代STAT3化学探针）。我们建议使用最活跃的第二代探针CPD188-15作为制作第三代探针的脚手架。计划的修改基于在第二代探针上进行的结构活性关系（SAR）分析的结果，并围绕磺酰基氯化物和酰胺的面板直接合成磺胺的直接合成。每种新型的磺胺化合物将在SPR分析中检查，在高吞吐量荧光显微镜（HTFM）测定中，将测试抑制IL-6刺激的细胞质至核易位易位，并针对STAT3与STAT1的STAT3相对于STAT1。 目标2。确定STAT3途径的抑制是否可以改善临床前MS分析和人异种移植模型中的现有癌症疗法。我们将使用MS形成抑制分析和人类乳腺癌异种移植模型来确定最活跃的第三代探针对STAT3抑制是否会提高常规治疗的体外和体内疗效。 除了确定STAT3对乳腺癌干细胞存活和自我更新的贡献外，这些临床前研究还可以为未来临床试验的设计提供信息，并确定抑制干细胞自我更新和治疗耐药性途径是否可以改善患者的现有乳腺癌疗法。 公共卫生相关性：一小部分乳腺癌细胞无法应对通常的治疗，并引起复发性疾病。该建议概述了旨在开发针对这些耐药细胞的小分子探针的化学和生物学研究。如果这些研究成功，这些小分子探针可能与当前的乳腺癌治疗相结合，从而防止癌症复发并导致治愈。

项目成果

Monoclonal Antibodies Specific for STAT3β Reveal Its Contribution to Constitutive STAT3 Phosphorylation in Breast Cancer.

• DOI: 10.3390/cancers6042012
• 发表时间: 2014-09-29
• 期刊: Cancers
• 影响因子: 5.2
• 作者: Bharadwaj U;Kasembeli MM;Eckols TK;Kolosov M;Lang P;Christensen K;Edwards DP;Tweardy DJ
• 通讯作者: Tweardy DJ