CAPER, a New Regulator of DNA Damage and Repair in Triple Negative Breast Cancer

CAPER，三阴性乳腺癌 DNA 损伤和修复的新调节剂

• 批准号: 10359895
• 负责人: Jean-Francois Jasmin
• 金额: $ 43.5万
• 依托单位: SAINT JOSEPH'S UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-21 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10359895
• 关键词: ABL1 gene; Apoptosis; Apoptotic; Area; Biochemical; Breast Cancer Cell; Breast Cancer cell line; CASP3 gene; Cancer Cell Growth; Cell Count; Cell Cycle; Cell Death; Cell model; Cells; Cessation of life; Chemotherapy and/or radiation; Clinical; DNA Damage; DNA Repair; DNA Repair Gene; DNA Repair Pathway; Data; Development; Diagnosis; Disease; Epidermal Growth Factor Receptor; Estrogen Receptors; Future; Growth; Hormonal; Hormones; Human; Immunocompetent; Immunocompromised Host; Immunologic Surveillance; Impairment; In Vitro; Institution; Lead; Left; MDA MB 231; Malignant Neoplasms; Mammary Gland Parenchyma; Modality; Modeling; Molecular; Morbidity - disease rate; Outcome; Pathway interactions; Patients; Phosphorylation; Play; Progesterone Receptors; Prognosis; Proteins; Radiation therapy; Research; Role; Signaling Molecule; Specimen; Students; Suggestion; Survival Rate; Testing; Transcription Factor AP-1; Woman; Work; Xenograft procedure; anticancer research; breast cancer progression; cancer care; cancer cell; cancer subtypes; cancer therapy; chemotherapeutic agent; clinically relevant; cytotoxic; experimental study; in vivo; knock-down; lentiviral-mediated; malignant breast neoplasm; mortality; mouse model; novel; overexpression; precision oncology; prevent; protein activation; protein expression; receptor; response; small hairpin RNA; targeted treatment; treatment response; triple-negative invasive breast carcinoma

ABSTRACT Triple negative breast cancer (TNBC) has the poorest clinical outcome amongst all breast cancer subtypes. TNBC lacks the expression of the three major receptors found in other subtypes (estrogen receptor [ER], progesterone receptor, and/or hormone epidermal growth factor receptor-2) making this cancer particularly challenging with regards to treatment modalities. Novel targeted treatments that could kill TNBC cells or sensitize them to chemo- and radiation therapies are highly coveted to increase survival of these patients. Due to its fast proliferative rate, TNBC relies heavily on DNA repair mechanisms for its survival and proteins involved in this important checkpoint are attractive targets for cancer treatment. CAPER (Rbm39) protein was recently shown to be overexpressed in breast cancer specimens compared to normal breast tissues. While CAPER knockdown inhibits breast cancer cell growth, its role on DNA damage and repair mechanisms in breast cancer and its role in TNBC progression and response to chemo- and radiation therapies remain completely unexplored. Our preliminary data demonstrate that knockdown of CAPER expression in TNBC cells increases DNA damage as reflected by increased phosphorylation of H2AX and ATM. The decreased total cell number and increased caspase-3/7 cleavage observed following CAPER knockdown in MDA-MB-231 and BT549 TNBC cells is suggestive of insurmountable DNA damage leading to programmed cell death (apoptosis). The effect of CAPER knockdown on DNA damage in TNBC cells was cell cycle-independent and selective to cancer cells, as non- tumorigenic cells lack the expression of CAPER and remain unaffected following delivery of lentiviral CAPER shRNAs. Our preliminary results also revealed that DNA repair proteins RAD-51, C-Alb and RB were significantly downregulated in TNBC following CAPER knockdown. We posit that CAPER overexpression in TNBC plays an important role in protection against DNA damage by optimizing DNA repair pathways. The current proposal builds on our previous work and preliminary results and aims to delineate the roles of CAPER in basal DNA damage/repair pathways and to determine its clinical relevance in TNBC growth using both immunocompromised (xenograft) and immunocompetent (syngeneic) orthotopic mouse models (Aim 1). Importantly, we will also use these TNBC cells and mouse models to test the unexplored role of CAPER in the response to DNA damaging chemo- and radiation therapies in both in vitro and in vivo settings (Aim 2). The current proposal will validate the role of CAPER as an important signaling molecule in the progression of TNBC as well as response to DNA damage using clinically relevant models that also incorporate immune surveillance and will be insightful in the further development of targeted therapies for the treatment of TNBC.

摘要 三阴性乳腺癌（TNBC）在所有乳腺癌亚型中具有最差的临床结果。 TNBC缺乏在其他亚型中发现的三种主要受体（雌激素受体[ER]， 孕激素受体和/或激素表皮生长因子受体-2），使这种癌症特别 在治疗方式上具有挑战性。可以杀死TNBC细胞或致敏的新型靶向治疗 他们对化疗和放射治疗的渴望是非常高的，以增加这些患者的存活率。由于其快速 由于TNBC的增殖率很高，它的存活在很大程度上依赖于DNA修复机制和参与此过程的蛋白质。 重要检查点是癌症治疗有吸引力的靶点。CAPER（Rbm 39）蛋白最近被证明是 与正常乳腺组织相比，在乳腺癌标本中过度表达。当CAPER击倒 抑制乳腺癌细胞生长，其对DNA损伤和修复机制的作用及其在乳腺癌中的作用 在TNBC中，进展和对化疗和放疗的反应仍然完全未被探索。我们 初步数据表明，TNBC细胞中CAPER表达的敲低增加了DNA损伤， 这通过H2 AX和ATM的磷酸化增加来反映。细胞总数减少， 在MDA-MB-231和BT549 TNBC细胞中CAPER敲低后观察到的胱天蛋白酶-3/7裂解是 提示不可克服的DNA损伤导致程序性细胞死亡（凋亡）。CAPER的效果 TNBC细胞中DNA损伤的敲低是细胞周期无关的，并且对癌细胞具有选择性，因为非 致瘤细胞缺乏CAPER表达，并且在慢病毒CAPER递送后不受影响 shRNAs。我们的初步结果还表明，DNA修复蛋白RAD-51、C-Alb和RB在细胞内的表达与细胞凋亡的发生有显著的相关性。 在CAPER敲低后TNBC中下调。我们认为CAPER在TNBC中的过度表达在肿瘤的发生发展中起着重要作用。 通过优化DNA修复途径，在保护DNA免受损伤中发挥重要作用。现时的建议 建立在我们以前的工作和初步结果，旨在描绘CAPER在基础DNA中的作用 损伤/修复途径，并使用免疫功能低下和免疫功能不全两种方法确定其在TNBC生长中的临床相关性。 （异种移植）和免疫活性（同基因）原位小鼠模型（Aim 1）。重要的是，我们还将使用 这些TNBC细胞和小鼠模型来测试CAPER在DNA损伤反应中未探索的作用， 在体外和体内环境中的化学和放射疗法（目标2）。目前的提案将验证 CAPER作为重要信号分子在TNBC进展中的作用以及对DNA的应答 损伤使用临床相关模型，也包括免疫监视，并将在深入了解 进一步开发用于治疗TNBC的靶向疗法。