Overcoming BRAF and MEK Inhibitors Resistance in Advanced Melanoma

克服晚期黑色素瘤中的 BRAF 和 MEK 抑制剂耐药性

• 批准号: 9205456
• 负责人: Niramol Savaraj
• 金额: --
• 依托单位: MIAMI VA HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9205456
• 关键词: Address; Aftercare; Ammonia; Antibodies; Antitumor Response; Apoptosis; Apoptotic; Arginine; Arginine deiminase; Attenuated; Autophagocytosis; BRAF gene; Biochemical; Biological Assay; Blood Circulation; Cell Death; Cell Line; Cells; Cessation of life; Citrulline; Clinic; Clinical; Clinical Trials; Clinical Trials Design; Cutaneous Melanoma; Cytotoxic T-Lymphocyte-Associated Protein 4; Data; Disease; Disease Progression; Drug Targeting; Drug resistance; Enzymes; Exhibits; Failure; Future; Genes; Goals; Grant; Growth; Heat shock proteins; Hypersensitivity; Immune checkpoint inhibitor; Immunotherapy; In Vitro; Laboratory Finding; Ligands; Ligase; Lymphocyte; MEKs; Melanoma Cell; Modality; Mutation; Normal Cell; Organelles; PDCD1LG1 gene; Patients; Pharmaceutical Preparations; Phase; Progressive Disease; Publishing; Ras/Raf; Recombinants; Relapse; Reporting; Resistance; Role; Salvage Therapy; Sampling; Signal Transduction; Stable Disease; Survival Rate; Time; Toxic effect; Translating; Treatment outcome; Work; antitumor effect; argininosuccinate synthase; base; c-myc Genes; clinically relevant; combinatorial; deprivation; improved outcome; in vivo; inhibitor/antagonist; killings; melanoma; neoplastic cell; novel; outcome forecast; programs; public health relevance; resistance mechanism; response; targeted agent; treatment planning; tumor; tumor growth; urea cycle

 DESCRIPTION (provided by applicant): BRAF inhibitor (BRAFi) has emerged as one of the key treatments for BRAFV600E mutation which accounts for 60% of cutaneous melanomas. While the response rate is high and responses can be rapid, relapse is inevitable and often occurs within 6 months. The addition of MEK inhibitor (MEKi) could increase the duration of response from 6 to 9 months and increase one year survival to 40%. However, relapse invariably occurs and there is no effective salvage treatment available. Another approach is the use of immunotherapy with checkpoint inhibitors. Ipilimumab (anti-CTLA 4 antibody) and anti-programmed death 1 (anti-PD1) antibody (Nivolumab and Pembrolizumab) showed an increase in duration of response (99 weeks) and increased overall survival (63% one year survival rate). However, the time to response is often long for these agents, and when rapid disease progression occurs, especially after BRAF failure, patients may not be able to complete the planned treatment course, as has been reported for ipilimumab. Currently, there is a paucity of published data on the antitumor activity of anti-PD1 and anti-PD-L1 after BRAFi failure or BRAFi and MEKi failure patients. In this application, we plan to target to treat this group of patients which has rapid progressive disease and extremely poor prognosis. Our preliminary data showed that these resistant cells are very sensitive to arginine deprivation and pegylated arginine deiminase (ADI-PEG20) which degrades arginine to citrulline produced >80% decrease in these resistant tumors in vivo. We plan to investigate the underlying mechanism(s) and translate this into clinical trial. Our previou work and others have shown that certain melanomas do not express argininosuccinate synthetase (ASS), a key enzyme in the urea cycle, to synthesize arginine. These tumors depend on exogenous arginine to survive. ADI-PEG20 inhibits tumor growth with minimal toxicity since normal cells can take up citrulline to make arginine. However, we have found that autophagy does occur which can blunt the antitumor effect and re-expression of ASS can develop. These two mechanisms can account for drug resistance seen with this treatment. Importantly, we have found that cMyc is a positive regulator for re- expression of ASS. Interestingly, we have found that both BRAF resistant (BR) and dual resistant [resistant to both BRAFi and MEKi (BMR)] cells cannot readily undergo autophagy due to decrease in AMPK1-α and Atg5. This makes these resistant cells exquisitely sensitive to ADI-PEG20 treatment. In addition, both BR and BMR cells are unable to re-express ASS gene due to decrease in cMyc, and hence they cannot evade the apoptotic effect by ADI-PEG20 treatment. We plan to investigate how cMyc, AMPK1-α, and Atg5 are down regulated. Importantly, we plan to investigate the clinical relevance of our laboratory findings by examining tumor samples obtained from BR and BRM patients for AMPK1-α, Atg5 and ASS expression and for ADI-PEG20 sensitivity using tumor explant and primary culture as outlined in aim 2. Clinically, BR and BMR patients usually progress very rapidly and ADI-PEG20 alone may not be sufficient to control the tumor. In aim 3, we plan to investigate which combination with ADI-PEG20 yields the best antitumor efficacy. Based on our preliminary data, we plan to combine ADI-PEG20 with MEKi in BR tumors and ADI-PEG20 with Hsp-90 inhibitors in BMR tumors. Our ultimate goal is to apply this combination to treat this group of extremely poor prognosis patients. Immune checkpoint inhibitors have become a major component for the treatment of melanoma, and the effect of ADI- PEG20 on PD-1 and PD-L1 expression has not been explored. Our preliminary data showed that ADI-PEG20 can upregulate PD-L1 in BR and BMR cells, which may potentiate the antitumor effect of anti-PD-1 and anti- PD-L1 antibody. We plan to examine tumor explants, BR, and BMR cells for PD-1/PD-L1 expression before and after ADI-PEG20 treatment. Furthermore, we will also examine PD-1 expression from lymphocytes in these patients before and after treatment with ADI-PEG20. Thus, future combinatorial treatment using both agents can be rationally formulated to treat ASS (-) melanoma patients.

 描述（由申请人提供）： BRAF抑制剂（BRAFi）已成为治疗占皮肤黑色素瘤60%的BRAFV600E突变的关键疗法之一，虽然反应率高且反应迅速，但复发是不可避免的，并且通常在6个月内发生。 MEK抑制剂（MEKi）可以将缓解持续时间从6个月延长至9个月，并将一年生存率提高至40%，但总是会出现复发，并且没有有效的挽救方法。另一种治疗方法是使用检查点抑制剂 Ipilimumab（抗 CTLA 4 抗体）和抗程序性死亡 1（抗 PD1）抗体（Nivolumab 和 Pembrolizumab），显示缓解持续时间延长（99 周）。并提高总体生存率（63% 的一年生存率），但这些药物的缓解时间往往很长，而且当疾病快速进展时，尤其是 BRAF 失败后，患者可能无法完成治疗。目前，关于 BRAFi 失败或 BRAFi 和 MEKi 失败患者的抗肿瘤活性的已发表数据很少。我们的初步数据表明，这些耐药细胞对精氨酸剥夺和聚乙二醇化精氨酸非常敏感。脱亚胺酶 (ADI-PEG20) 将精氨酸降解为瓜氨酸，在体内研究这些耐药肿瘤的数量减少了 80% 以上。我们计划研究其潜在机制，并将其转化为临床试验，我们之前的工作和其他研究表明，某些黑色素瘤。不表达精氨酸琥珀酸合成酶（ASS），这是尿素循环中合成精氨酸的关键酶，这些肿瘤依赖于外源精氨酸生存。 ADI-PEG20 以最小的毒性抑制肿瘤生长，因为正常细胞可以吸收瓜氨酸来产生精氨酸。然而，我们发现自噬确实会发生，这会削弱抗肿瘤作用，并且可以解释 ASS 的重新表达。重要的是，我们发现 cMyc 是 ASS 重新表达的正调节因子。 BRAFi 和 MEKi (BMR)] 细胞由于 AMPK1-α 和 Atg5 的减少而不易发生自噬，这使得这些耐药细胞对 ADI-PEG20 处理极其敏感。此外，BR 和 BMR 细胞都无法重新表达 ASS。由于 cMyc 的减少，它们无法逃避 ADI-PEG20 治疗的细胞凋亡效应，我们计划研究 cMyc、AMPK1-α 和重要的是，我们计划使用肿瘤外植体和原代培养物，通过从 BR 和 BRM 患者获得的肿瘤样本来研究我们的实验室结果的临床相关性，包括 AMPK1-α、Atg5 和 ASS 表达以及 ADI-PEG20 敏感性。目标2。临床上，BR和BMR患者通常进展非常迅速，单独使用ADI-PEG20可能无法控制肿瘤。在目标3中，我们计划研究与哪种组合。根据我们的初步数据，我们计划将 ADI-PEG20 与 MEKi 结合治疗 BR 肿瘤，将 ADI-PEG20 与 Hsp-90 抑制剂结合治疗 BMR 肿瘤，我们的最终目标是将这种组​​合应用于治疗。这组预后极差的患者已成为治疗黑色素瘤的主要成分，ADI-PEG20对PD-1和PD-1的影响。 PD-L1 表达尚未被探索。我们的初步数据表明，ADI-PEG20 可以上调 BR 和 BMR 细胞中的 PD-L1，这可能会增强抗 PD-1 和抗 PD-L1 抗体的抗肿瘤作用。检查 ADI-PEG20 治疗前后肿瘤外植体、BR 和 BMR 细胞的 PD-1/PD-L1 表达 此外，我们还将检查这些患者治疗前后淋巴细胞的 PD-1 表达。因此，未来可以合理制定使用这两种药物的组合治疗来治疗 ASS (-) 黑色素瘤患者。