Novel approach of targeting AT-rich S/MAR regions for treating therapy resistant breast cancers

尽管有缺陷的DNA损伤反应(DDR)，癌细胞仍具有独特的修复其DNA并持续的能力 它们的DNA复制。更高的DNA复制率和更高的DNA修复活性(尽管容易出错) 虽然确保了不受控制的增殖，但也会在癌细胞中产生高频率的基因突变。 这种细胞DNA的改变和癌细胞对不断复制的依赖最初成为 将DNA作为癌症治疗的靶点是合理的。虽然在某种程度上取得了成功，但 目前临床上使用的DNA靶向药物包括危及生命的毒性、获得性耐药性和 继发性癌症的发生。这些问题主要源于DNA靶向药物 不分青红皂白地结合到细胞DNA或其他非DNA大分子上，导致DNA损伤。我们推论 新的DNA相互作用药物(1)表现出高的序列/区域特异性(2)不直接损伤DNA 以及(3)肿瘤细胞使用的靶向DNA相关过程而不是正常细胞可能具有有利的 治疗效果。在这项提案中，我们提供了令人信服的证据，证明咔唑蓝(CB)可能是 我们最近开发的这种药物。我们以咔唑为原料合成了炭黑，咔唑是一种煤的活性成分 用于治疗牛皮癣的焦油。使用一种无偏见的全基因组方法，我们发现CB 与A/T富含DNA的区域相互作用。重要的是，使用细胞系、患者来源的体外植入体(PDEx)， 患者衍生的器官(PDO)和异种移植物(PDX)以及原位异种移植模型，我们发现在 与化疗药物相比，CB是一种有效且安全的抗癌化合物，可作为CB的全身给药 抑制TNBC和ER+乳腺癌(BCS)的生长和进展，不会产生任何毒性。我们 发现CB抑制A/T富含结合蛋白HMGA1的活性，从而抑制几种 CDK4、MCMS、gins和CDC6等基因在这些BC中高表达并发挥关键作用 在复制和DNA修复中的作用。重要的是，HMGA1及其靶蛋白被报道调节PARP 抑制物(PARPI)和CDK4/6抑制物(CDK4/6I)分别在TNBC和转移性ER+BCS中的反应。 提出了三个具体目标：在Aim1中，我们将检验CB优先针对特定目标的假设 DNA中对癌细胞增殖/进展起关键作用的区域，选择性地诱导癌细胞 死亡。在目标2中，我们将阐明CB利用HMGA1等靶基因致敏的机制 PARPI和CDK4/6I反应分别抑制TNBC和ER+BCS的生长/转移。在……里面 目的3，我们将检验CB作为一种新的、安全有效的抗肿瘤药物和治疗药物的假设 使用PDX、PDO和PDEx模型治疗BCS的佐剂。我们还将建立所需的PK/PD参数 为今后CB的临床发展提供参考。这项研究的成功完成将为新的范式奠定基础 使用CB作为治疗手段来治疗BCS。

Cancer cells despite defective DNA damage response (DDR) have unique ability to repair their DNA and continue their DNA replication. The higher rate of DNA replication and heightened DNA repair activity (albeit error-prone) though ensure uncontrolled proliferation but also produce genetic mutations at high frequencies in cancer cells. This alteration of cellular DNA and dependency of cancer cells to incessant replication initially became the justification for targeting DNA as a cancer therapy. Though successful to some extent, the major limitations of DNA targeting drugs that are used in clinics today include life threatening toxicity, acquired resistance and occurrence of secondary cancers. These problems mostly stem from the ability of DNA targeting drugs to indiscriminately bind to cellular DNA or other non-DNA macromolecules resulting in DNA damage. We reason new DNA interacting drugs that (1) display high sequence/region specificity (2) do not directly damage the DNA and (3) target DNA-related processes that tumor cells use but not the normal cells could have favorable therapeutic outcomes. In this proposal, we provide compelling evidence that Carbazole Blue (CB) may be one such drug that we recently developed. We synthesized CB from carbazole, which is an active ingredient of coal tar that is used for the treatment of Psoriasis. Using an unbiased genome-wide approach, we discovered that CB interacts with A/T rich DNA regions. Importantly, using cell lines, patient-derived ex-vivo explants (PDEx), patient-derived organoids (PDO) and xenografts (PDX) as well as orthotopic xenograft models, we found that in contrast to chemotherapy drugs, CB is a potent and safe anti-cancer compound as systemic delivery of CB inhibits growth and progression of TNBC and ER+ breast cancers (BCs) without inducing any toxicity. We discovered that CB inhibits the activity of A/T rich binding protein HMGA1 and consequently expression of several genes including CDK4, MCMs, GINS and CDC6 and that are highly expressed in these BCs and play critical roles in replication and DNA repair. Importantly, HMGA1 and its target proteins are reported to regulate PARP inhibitor (PARPi) and CDK4/6 inhibitor (CDK4/6i) responses in TNBC and metastatic ER+BCs, respectively. Three Specific Aims are proposed: In Aim1, we will test the hypothesis that CB preferentially targets specific domains in the DNA that are critical for cancer cell proliferation/progression to selectively induce cancer cell death. In Aim 2, we will elucidate the mechanisms by which CB utilizes target genes such as HMGA1 to sensitize PARPi and CDK4/6i responses leading to growth/metastasis inhibition of TNBC and ER+BCs, respectively. In Aim 3, we will test the hypothesis that CB serves as a novel, safe and potent anti-tumor agent and therapeutic adjuvant for treating BCs using PDX, PDO and PDEx models. We will also establish PK/PD parameters required for future clinical development of CB. Successful completion of this study will set the stage for a new paradigm of treating BCs using CB as a therapeutic.