Synergize a novel homologous recombination inhibitor with DNA damagingagents in TNBC

15%-20%的乳腺癌是三重阴性的，缺乏分类和定义的三种受体 大多数乳腺癌的治疗策略：雌激素受体(ER)、孕激素受体(PR)和ERB2 (也称为HER2)。正因为如此，没有针对TNBC患者的靶向治疗。这构成了一个 贫困状况，因为TNBC是一种侵袭性癌症，不成比例地影响年轻女性和 有非洲血统的。目前，对TNBC患者的标准护理包括手术、放射治疗和 化疗，后两种药物都有毒副作用。聚ADP核糖聚合酶抑制物(PARPI) FDA批准单一疗法用于BRCA1/2缺陷的TNBC患者，因为他们存在DNA缺陷 PARPI加剧了修复，从而导致癌细胞被杀死。然而，约80%的TNBC 患者是BRCA1/2基因的野生型，因此没有资格接受PARPI治疗或停止对PARPI的反应 DNA修复修复是常见的PARPI抗性机制之一。我们测试了一个小说图书馆 通过抑制同源重组(HR)介导的DNA DSB修复的化合物(硝基脂肪酸) 特异性和可逆地加成重组酶RAD51，从而抑制其活性。主要候选人(CP- 8)被鉴定为在精通HR的TNBC细胞中化学诱导HR缺陷(HRD)DNA修复。 介导的DNA修复和协同DNA损伤处理，如PARPI和电离辐射(IR)。 对小鼠的初步毒性研究表明，CP-8没有不良反应，它不仅能抑制TNBC肿瘤 当与PARP抑制剂在体外和体内联合生长时，还可以减轻PARP的毒副作用 骨髓细胞上的抑制剂。我们的主要工作假设是CP-8是一种安全、可逆和有效的 HR熟练(幼稚或PARPI抗性)的原发和脑转移TNBC组织对DNA的增敏作用 通过减少RAD51功能来破坏治疗。此外，我们预计，CP-8的共同治疗将 允许减少DNA损伤剂的剂量，从而减少患者的毒副作用。目标1将审查一个 CP-8与DNA药物协同作用的TNBC细胞板、TNBC PDX外植体及体内小鼠模型 破坏剂的作用机理各不相同。三株抗PARPI(ola、tala和NIR)的TNBC细胞株已被 已经在实验室中产生，以评估CP-8对PARPI的再增敏作用。PDX型号选自 最近的一项研究考虑到它们对DNA损伤剂的反应相对较低。RAD51的目标交战 通过CP-8以及DNA DSB将在细胞系、TNBC PDX外植体和体内组织中进行评估并进行相关性 有药效的。细胞系和组织将通过已经建立的点击化学辅助亲和力进行分析 捕获和高效液相色谱-MS/MS检测可能的额外CP-8靶标和代谢物含量。AIM 2将执行IND 与Pharma Directions合作进行体外和体内CP-8药理学研究 短期目标是为第2阶段(R42)评估准备CP-8。

15-20% of all breast cancers are triple negative, being devoid of the three receptors that classify and define treatment strategies for most mammary cancers: estrogen receptor (ER), progesterone receptor (PR) and ERB2 (also known as HER2). Because of this, no targeted therapies are available for TNBC patients. This poses a destitute situation, as TNBC is an aggressive cancer that disproportionally affects younger women and those having African origins. Currently, standard care for TNBC patients includes surgery, radiation treatment and chemotherapy, where the two latter have toxic side effects. Poly-ADP-ribose polymerase inhibitor (PARPi) monotherapy is FDA approved in BRCA1/2-deficient TNBC patients as they present with deficiencies in DNA repair which are exacerbated by PARPi and thus lead to killing of cancer cells. However, about 80% of all TNBC patients are wild type for BRCA1/2 genes and thus not eligible for PARPi therapies or stop responding to PARPi as restoration of DNA repair is one of the frequent PARPi resistance mechanism. We tested a library of novel compounds (nitro fatty acids) that inhibit homologous recombination (HR)-mediated DNA DSB repair through specifically and reversibly adducting to the recombinase RAD51 thus inhibiting its activity. A lead candidate (CP- 8) was identified that induces chemically an HR-defect (HRD) DNA repair in TNBC cells proficient in HR- mediated DNA repair and synergizes with DNA damaging treatments such PARPi and ionizing radiation (IR). Preliminary toxicity studies in mice showed no adverse effects by CP-8 which not only diminishes TNBC tumor growth when combined with PARP inhibitors in vitro and in vivo, but also alleviates toxic side effects of PARP inhibitors on bone marrow cells. Our overarching working hypothesis is that CP-8 is a safe, reversible and potent sensitizer of HR-proficient (naïve or PARPi resistant) primary and brain metastatic TNBC tissues to DNA damaging therapies by reducing RAD51 functionality. Moreover, we expect that co-treatment of CP-8 would allow dose reduction of DNA damaging agent thus reducing toxic side effects in patients. Aim 1 will examine a TNBC cell line panel, TNBC PDX explants and in vivo mouse models for drug synergism of CP-8 with DNA damaging agents varying in mechanism. Three PARPi (ola, tala and nir) resistant TNBC cell lines have been already generated in the laboratory to assess re-sensitization to PARPi by CP-8. PDX models were chosen from a recent study considering their relative low response to DNA damaging agents. Target engagement of RAD51 by CP-8 as well as DNA DSB will be assessed in cell lines, TNBC PDX explants and in vivo tissues and correlated with drug efficacies. Cell lines and tissues will be analyzed by already established click chemistry-assisted affinity capture and HPLC-MS/MS for possible additional CP-8 targets and metabolite content. Aim 2 will perform IND enabling studies of the in vitro and in vivo CP-8 pharmacology in collaboration with PharmaDirections with the short-term goal to prepare CP-8 for a Phase 2 (R42) evaluation.