Melanoma Resistance to Apoptosis: Mechanisms and Therapeutic Potential

黑色素瘤对细胞凋亡的抵抗：机制和治疗潜力

• 批准号: 8391110
• 负责人: DAVID A. NORRIS
• 金额: --
• 依托单位: VA EASTERN COLORADO HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8391110
• 关键词: Apoptosis; Apoptotic; BCL2 gene; Bortezomib; Cells; Characteristics; Clinical; Clinical Research; Clinical Trials; Collaborations; Combined Modality Therapy; Complex; Disease; Drug Combinations; Drug Targeting; Exhibits; Family; Future; Human; In Vitro; Incidence; Individual; Lead; Link; MCL1 protein; MG132; Malignant Neoplasms; Mediator of activation protein; Medical; Medicine; Melanoma Cell; MicroRNAs; Military Personnel; Mission; Modeling; Molecular; Oncologist; Paclitaxel; Patient Care; Patients; Pharmaceutical Preparations; Population; Pre-Clinical Model; Proteasome Inhibitor; Proteins; RNA Interference; Research; Resistance; Sampling; Scientist; Services; Signal Transduction; Skin; Stem cells; Sun Exposure; Techniques; Testing; Therapeutic; Treatment Efficacy; United States; Validation; Xenograft Model; Xenograft procedure; base; cancer stem cell; cancer therapy; chemotherapeutic agent; clinical care; cytotoxicity; effective therapy; experience; in vivo; in vivo Model; inhibitor/antagonist; killings; melanoma; member; mimetics; novel; novel strategies; novel therapeutic intervention; outcome forecast; research study; response; small molecule; success; temozolomide; therapeutic target; therapy resistant; treatment strategy; young woman

A fundamental characteristic of malignant melanoma is resistance to apoptosis, which largely determines melanoma's resistance to therapy. The complex interaction of pro-apoptotic and anti-apoptotic members of the Bcl-2 family is a central control point of apoptosis and a promising drug target. The BH3 mimetic ABT-737 is a potent small molecule inhibitor of the anti-apoptotic proteins Bcl-2/Bcl-XL/Bcl-w, and it exhibits promise for cancer treatment either as a single agent or in combination therapy. We have found that ABT-737 alone induced little cytotoxicity in melanoma cells, and knockdown experiments with RNAi techniques demonstrated that anti-apoptotic protein Mcl-1, but not Bcl-2 or Bcl-XL is the main mediator of melanoma resistance to ABT-737 treatment. In addition, ABT-737 displayed strong synergistic lethality when combined with either proteasome inhibitors (MG-132 or Bortezomib) or Paclitaxel, and mechanistic studies suggested that both proteasome inhibitors and Paclitaxel neutralize Mcl-1's functions. These exciting results indicate that drugs that neutralize Mcl-1 function are outstanding candidates for combination therapy with the ABT-737 for treating melanomas, and demand validation in preclinical models and further exploring the therapeutic potential of other drugs which target Mcl-1 in combination with ABT-737. It has also been proposed that cancer initiating cells (or cancer stem cells), which preferably initiate cancers, may be responsible for cancer resistance to therapy, and eliminating these cells may be essential for developing any cancer therapy with long term success. We will refer these cells as cancer imitating cells. We propose to investigate whether enriched melanoma initiating cells are more resistant to existing chemotherapeutic agents than non-sorted cells in melanoma, and to examine whether combinations of drugs that reduce multiple anti-apoptotic defenses such as ABT-737 plus Bortezomib or Paclitaxel will overcome this resistance of melanoma initiating cells. These studies will be an important component to understand whether melanoma initiating cells are more resistant to therapy. Specific Aim 1: To directly test the responses of enriched melanoma initiating cells to existing and new therapies in vitro. i) To determine whether enriched melanoma initiating cells are more resistant to conventional chemotherapeutic agents such as Temozolomide. ii) To determine whether combinations of ABT- 737 with either Bortezomib or Paclitaxel overcome the resistance in enriched melanoma initiating cells. Specific Aim 2: To verify the efficacy of the combinations of ABT-737 with either Bortezomib or Paclitaxel for treating melanoma using two novel xenotransplantation models: a model targeting human melanoma initiating cells in vivo, and a direct xenograft model for melanoma patient samples. Specific Aim 3: To investigate the therapeutic potential of combining BH3 mimetic ABT-737 with other compounds which inhibit Mcl-1. i) A new approach to down-regulating Mcl-1 in melanomas by microRNAs. ii) Other drugs known to inhibit Mcl-1. This project proposes to develop novel combination therapeutics by targeting multiple anti-apoptotic Bcl-2 members, and to verify the efficacy of the treatment combinations in killing melanomas, and most importantly, melanoma initiating cell populations. We believe that the studies proposed here will quickly lead to future clinical studies and to the clinical use of ABT-737 (or similar agents) in treating human melanoma patients. Importantly, this approach should not be restricted by different signaling signatures of individual melanomas. This proposal is a collaboration of experienced melanoma basic scientists, a skin stem cell expert, a melanoma oncologist, and an expert in xenotransplantation models of human cancers, and this team will make important advances in developing melanoma treatments based on reversing resistance to apoptosis.

恶性黑色素瘤的基本特征是对细胞凋亡的抗性，这在很大程度上决定了 黑色素瘤对治疗的抵抗力。促凋亡和抗凋亡成员的复杂相互作用 Bcl-2家族是凋亡的中心控制点，也是有前途的药物靶标。 BH3模拟ABT-737是一个 抗凋亡蛋白的有效的小分子抑制剂Bcl-2/bcl-xl/bcl-w，它表现出有望 癌症治疗是单一药物或联合疗法。 我们发现，仅ABT-737仅诱导黑色素瘤细胞的细胞毒性，而敲低实验 借助RNAi技术表明抗凋亡蛋白Mcl-1，而不是Bcl-2或Bcl-XL是主要的 黑色素瘤对ABT-737治疗的抗性介质。此外，ABT-737表现出强大的协同作用 当与蛋白酶体抑制剂（MG-132或硼替二比）或紫杉醇混合使用时致死性，并且 机械研究表明，蛋白酶体抑制剂和紫杉醇都可以中和Mcl-1的功能。 这些令人兴奋的结果表明，中和中和Mcl-1功能的药物是出色的候选者 与ABT-737联合疗法用于治疗黑色素瘤，并在临床前模型中验证 并进一步探索其他药物与ABT-737结合使用的其他药物的治疗潜力。 还提出，癌症引发细胞（或癌干细胞），最好启动癌症， 可能负责抗癌治疗的性，消除这些细胞可能是必不可少的 开发任何长期成功的癌症疗法。我们将这些细胞称为模仿细胞。我们 建议研究富集的黑色素瘤引发细胞是否对现有 化学治疗剂比黑色素瘤中的非排序细胞，并检查 减少多种抗凋亡防御的药物，例如ABT-737加硼替济或紫杉醇 克服黑色素瘤引发细胞的这种耐药性。这些研究将是 了解黑色素瘤引发细胞是否对治疗更具耐药性。 具体目的1：直接测试富集黑色素瘤启动细胞对现有细胞的反应和 体外新疗法。 i）确定富集的黑色素瘤引发细胞是否更具抵抗力 常规的化学治疗剂，例如替莫唑胺。 ii）确定ABT的组合是否 737与硼替二醇或紫杉醇一起克服了富含黑色素瘤的耐药性。 具体目标2：验证ABT-737与硼替佐米或 使用两个新型的异种移植模型治疗黑色素瘤的紫杉醇：一种针对人类的模型 黑色素瘤在体内启动细胞，以及用于黑色素瘤患者样品的直接异种移植模型。 特定目的3：研究将BH3模拟ABT-737与其他的治疗潜力 抑制MCL-1的化合物。 i）一种新的方法，可以通过microRNA中的黑色素瘤中下调MCL-1。 ii）其他已知抑制MCL-1的药物。 该项目建议通过靶向多种抗凋亡Bcl-2来开发新型组合治疗剂 成员，并验证治疗组合在杀死黑色素瘤中的功效，最重要的是 黑色素瘤引发细胞群体。我们认为，这里提出的研究将很快导致未来 临床研究和ABT-737（或类似药物）在治疗人黑色素瘤患者中的临床使用。 重要的是，这种方法不应受个人的不同信号签名的限制 黑色素瘤。该建议是经验丰富的黑色素瘤基础科学家的合作，是皮肤干细胞 专家，黑色素瘤肿瘤学家以及人类癌症的异种移植模型的专家，该团队 基于对凋亡的抗药性，将在开发黑色素瘤治疗方面取得重要进展。