Developing an Artemis Nuclease Inhibitor to Potentially Treat Acute Lymphoblastic Leukemia

 描述(由申请人提供)：目前治疗急性淋巴细胞白血病(ALL)的方法最初是消除癌细胞，但在许多情况下，疾病最终会复发。大多数化疗药物不区分癌细胞和其他频繁分裂的细胞，无意中会对现有的免疫系统和骨髓、上皮细胞和胃肠道造成损害。因此，除了表皮和胃肠道系统的副作用外，患者还会受到免疫抑制，容易受到感染和其他恶性肿瘤的影响。理想的治疗方法是选择性地清除所有细胞，而不影响免疫系统。一种针对Artemis核酸酶的小分子抑制剂将专门针对ALL和早期淋巴样细胞，而不会影响现有的成熟淋巴细胞库。早期的淋巴细胞进行V(D)J重组，产生各种各样的抗体和T细胞受体。Artemis对于打开由染色体中的RAG蛋白产生的DNA发夹是必不可少的。抑制Artemis可阻止V(D)J重组过程中双链断裂(DSB)的分解，从而导致染色体断裂。在Artemis缺陷的ALL细胞中观察到了较慢的增殖和细胞死亡。Artemis抑制剂将选择性地在RAG表达细胞，如ALL和前-B和前-T细胞中产生DSB。成熟的淋巴细胞和其他类型的细胞不表达RAG，也不会受到影响；出生时没有Artemis的人只要通过骨髓移植接受替代免疫系统，只要他们不接受化疗或放射，就没有问题，这表明完全的Artemis抑制剂对患者的副作用最小或没有。因此，癌细胞将成为特定的靶点，而不会破坏已建立的免疫系统。Artemis在解决辐射和依托泊苷产生的DSB方面也很重要，这两种药物都通常用于治疗癌症。Artemis抑制剂可能会增加淋巴和非淋巴癌细胞对放射治疗和依托泊苷治疗的敏感性。对超过43.3万种化合物的库进行了筛选，以寻找潜在的Artemis抑制剂。候选化合物正在使用基于凝胶的生化分析进行评估。使用其他核酸酶的反筛选试验将选择Artemis特异性抑制。这些化合物还将在细胞测试中测试它们杀死原代ALL细胞和抑制V(D)J重组的能力。总体目标是开发一种针对Artemis的小分子抑制剂，在不影响免疫系统的情况下潜在地针对所有细胞。该抑制剂预计还将与放射治疗和依托泊苷治疗协同工作，以提高除ALL外的各种上皮性、间叶性和造血系统恶性肿瘤的治疗效率。

 DESCRIPTION (provided by applicant): Current treatments for acute lymphoblastic leukemia (ALL) eliminate cancer cells initially, but in many cases, the disease eventually recurs. Most chemotherapeutics do not distinguish between cancer cells and other frequently dividing cells, causing inadvertent damage to the existing immune system and bone marrow, epithelial cells, and GI tract. Thus, patients become immunosuppressed and vulnerable to infection and other malignancies, in addition to the side effects in their epidermis and GI system. An ideal treatment would selectively eliminate ALL cells without affecting the immune system. A small molecule inhibitor against the Artemis nuclease would specifically target ALL and early lymphoid cells without affecting the existing pool of mature lymphocytes. Early lymphocytes undergo V (D) J recombination, producing a diverse array of antibodies and T-cell receptors. Artemis is essential to opening the DNA hairpins created by RAG proteins in the chromosome. Inhibiting Artemis prevents the resolution of double-strand breaks (DSBs) during V (D) J recombination, resulting in chromosomal breaks. Slower proliferation and cell death has been observed in Artemis-deficient ALL cells. An Artemis inhibitor would selectively generate DSBs in RAG-expressing cells such as ALL and pre-B and pre-T cells. Mature lymphocytes and other cell types do not express RAG and will not be affected; humans born without Artemis are fine as long as they receive a replacement immune system via bone marrow transplantation, and as long as they do not receive chemotherapy or radiation, illustrating that a complete Artemis inhibitor would have minimal or no side effects for the patient. Hence, cancer cells will be specifically targeted without damaging the established immune system. Artemis is also important in resolving DSBs generated by radiation and etoposide, both of which are commonly used to treat cancer. An Artemis inhibitor would likely increase the sensitivity of lymphoid and non-lymphoid cancer cells to radiation therapy and etoposide treatment. A library of more than 433,000 compounds was screened for potential Artemis inhibitors. Candidate compounds are being evaluated using a gel-based biochemical assay. Counter-screen assays using other nucleases will select for Artemis-specific inhibition. These compounds will also be tested in cellular assays for their ability to kill primary ALL cells and inhibit V (D) J recombination. The overall goal is to developa small molecule inhibitor for Artemis to potentially target ALL cells without affecting the immune system. This inhibitor is also projected to work synergistically with radiation therapy and etoposide treatment to improve treatment efficiency in a wide range of epithelial, mesenchymal, and hematopoietic malignancies in addition to ALL.