Identification of chemotherapeutic sensitizers

化疗增敏剂的鉴定

• 批准号: 8948391
• 负责人: Kyungjae Myung
• 金额: $ 45.62万
• 依托单位: NATIONAL HUMAN GENOME RESEARCH INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8948391
• 关键词: Biochemical; Bioinformatics; Biological Assay; Biological Markers; CHEK2 gene; Categories; Cell Death; Cell Line; Cells; Chemicals; Chimeric Proteins; Collaborations; Collection; DNA Damage; DNA Repair Pathway; DNA damage checkpoint; DNA repair protein; Exhibits; Future; Gene Targeting; Genes; Hereditary Nonpolyposis Colorectal Neoplasms; Human Cell Line; In Vitro; Inhibitory Concentration 50; Laboratories; Lead; Luciferases; Malignant Neoplasms; Mismatch Repair; Molecular; Molecular Bank; Mus; Pathway interactions; Pharmaceutical Preparations; Phosphotransferases; Production; Proliferating; Proteins; Proteolysis; Radiation; Radiation therapy; Signal Transduction; Small Interfering RNA; Specificity; Testing; Translational Research; Tumor Burden; United States National Institutes of Health; Xenograft procedure; base; cancer cell; cell killing; chemotherapeutic agent; chemotherapy; compound 30; endonuclease; fighting; genome-wide; high throughput screening; in vivo; killings; knockout gene; mouse model; novel; response; screening; small molecule; small molecule libraries; tumor

Chemotherapeutic and radiation treatments cause a variety of genotoxic insults that lead to cell death in rapidly proliferating cancer cells. To survive genotoxic insults, cancer cells depend on multiple DNA repair pathways. Depending on the types of genotoxic insult, cells use a specific DNA repair pathway. When a DNA repair pathway is compromised, cancer cells become more sensitive to certain genotoxic insults. The identification of chemotherapeutic agents acting on compromised DNA repair pathways in cancer cells would result in more efficient treatment of cancer cells. Such agents are potential sensitizers for radiation therapy. We found that ATAD5 protein is stabilized in response to almost all genotoxic insults. Thus, we hypothesized that ATAD5 would be a good biomarker to detect genotoxic insults. We generated a cell line expressing the ATAD5-luciferase fusion protein and showed that the fusion protein is also stabilized in response to genotoxic insults. We used this novel cell-based quantitative high-throughput ATAD5-luciferase assay and successfully screened over 300,000 compounds in the NIH chemical library in collaboration with the National Center for Advancing Translational Sciences (NCATS) and found 300 potential chemotherapeutic compounds. To identify DNA repair pathways targeted by the genotoxic compounds, we used 8 isogenic human cell lines with targeted gene knockouts in specific DNA repair pathways. Approximately 300 compounds were tested in survival assays on these cells and group into sub-categories based on their IC50 to kill these cells. We found a small molecule that killed a mismatch repair deficient cancer cells and two small molecules that killed parp1 deficient cancer cells more efficiently. We investigated whether the compound killing mismatch repair deficient tumor (Lynch syndrome tumor) can reduce tumor burden in vivo using xenograft mice as well as gene targeted mice models. The compound showed potential selective killing effect in both mice models. We also used this compound to dissect molecular functions of mismatch repair pathway. We found mismatch repair defendant DNA damage checkpoint activation and characterized detail molecular mechanisms in vitro. Mismatch repair specifically inhibits double strand break formation by endonuclease, XPF by activating CHK2-depedent DNA damage checkpoint. We also found that similar molecular mechanisms were used for selective killing effect in mismatch repair deficient tumors by the compound. In collaboration with NCATS, we also used the same ATAD5-luciferase cell line to identify compounds and siRNAs that inhibit the ATAD5 stabilization in response to genotoxic insults and have identified >80 compounds and >30 siRNAs. Genes identified from these siRNA screens will unveil the unknown mechanisms that inhibit proteolysis of DNA repair proteins in response to genotoxic insults. Two compounds from initial hits could be potential radiation and chemotherapeutic sensitizers in tumors. We found one compound inhibits general DNA damage response by destabilizing DNA damage response kinase(s). We have continued to study to identify targets of these compounds among genes identified from siRNA screening using bioinformatic analysis, epistatic analysis, as well as biochemical interactions.

化疗和放射治疗引起多种遗传毒性损伤，导致快速增殖的癌细胞的细胞死亡。为了在遗传毒性损伤中存活，癌细胞依赖于多种DNA修复途径。根据遗传毒性损伤的类型，细胞使用特定的DNA修复途径。当DNA修复途径受损时，癌细胞对某些遗传毒性损伤变得更加敏感。鉴定作用于癌细胞中受损DNA修复途径的化疗剂将导致癌细胞的更有效治疗。这类药物是放射治疗的潜在增敏剂。我们发现，ATAD 5蛋白是稳定的，几乎所有的遗传毒性的侮辱。因此，我们假设ATAD 5将是检测遗传毒性损伤的良好生物标志物。我们产生了表达ATAD 5-荧光素酶融合蛋白的细胞系，并显示融合蛋白也在响应于遗传毒性损伤时稳定。 我们使用这种新的基于细胞的定量高通量ATAD 5-荧光素酶测定，并与国家推进转化科学中心（NCATS）合作，在NIH化学库中成功筛选了超过30万种化合物，并发现了300种潜在的化疗化合物。为了鉴定遗传毒性化合物靶向的DNA修复途径，我们使用了8个在特定DNA修复途径中具有靶向基因敲除的同基因人类细胞系。在对这些细胞的存活测定中测试了大约300种化合物，并基于它们杀死这些细胞的IC 50将其分组为亚类。我们发现一种小分子可以杀死错配修复缺陷的癌细胞，两种小分子可以更有效地杀死parp 1缺陷的癌细胞。我们使用异种移植小鼠以及基因靶向小鼠模型研究了化合物杀伤错配修复缺陷型肿瘤（Lynch综合征肿瘤）是否可以降低体内肿瘤负荷。该化合物在两种小鼠模型中均显示出潜在的选择性杀伤作用。我们还利用这种化合物来剖析错配修复途径的分子功能。我们发现错配修复被告DNA损伤检查点激活，并表征了详细的分子机制在体外。错配修复通过激活CHK 2依赖性DNA损伤检查点特异性抑制核酸内切酶XPF引起的双链断裂形成。我们还发现类似的分子机制用于化合物对错配修复缺陷肿瘤的选择性杀伤作用。 与NCATS合作，我们还使用相同的ATAD 5-荧光素酶细胞系来鉴定响应于遗传毒性损伤而抑制ATAD 5稳定化的化合物和siRNA，并且已经鉴定了>80种化合物和>30种siRNA。从这些siRNA筛选中鉴定的基因将揭示抑制DNA修复蛋白对遗传毒性损伤的蛋白水解的未知机制。两个化合物从最初的命中可能是潜在的放射和化疗增敏剂在肿瘤中。我们发现一种化合物通过使DNA损伤反应激酶不稳定来抑制一般的DNA损伤反应。我们继续研究，以确定这些化合物的靶基因中确定的siRNA筛选使用生物信息学分析，上位性分析，以及生化相互作用。