Reading mitochondrial apoptotic signaling to identify active cancer therapeutics

总结 我是一名肿瘤学家和癌症生物学家，负责监督一个实验室，该实验室专注于确定治疗方法， 选择性诱导癌细胞凋亡。我对细胞凋亡领域的最初贡献来自于 某些促凋亡BCL-2家族仅有BH 3的蛋白质转化为“敏化剂”和“激活剂”， 功能这一发现激发了我的兴趣，我想用药物来抑制BCL-2的功能， 促凋亡蛋白的BH 3结构域。我设计了第一个小鼠模型， BCL-2本身的功能可能足以使癌症缓解。接下来，我设计了一个工具， 将线粒体暴露于基于两亲性α- 促凋亡蛋白的螺旋BH 3结构域和测量线粒体外膜透化 （MOMP）。通过使用某些选择性相互作用的BH 3肽，我可以使用BH 3谱来识别细胞， 对BH 3的抑制作用特别敏感。我使用BH 3分析来帮助启动临床试验项目， BCL-2抑制剂Venetoclax在几种疾病中的应用迄今为止，其中最成功的方案是 慢性淋巴细胞性白血病和急性髓细胞性白血病，前者已经获得FDA批准， 批准。 使用不同的BH 3肽，BH 3谱可以测量总体凋亡引发或接近阈值 细胞凋亡。我们利用这一方面来证明差异凋亡启动可能是最重要的 化疗成功的重要决定因素。此外，差异性凋亡启动是细胞凋亡的主要机制。 常规化疗有治疗指数的主要原因-大多数非恶性体细胞癌 细胞比化学敏感的癌细胞更不容易发生凋亡。基于这一发现，我们问 我们是否能找到药物来选择性地增强癌细胞的凋亡启动。我们发现 我们可以在癌细胞暴露于有效药物的数小时内测量到凋亡启动的增加， 使用动态BH 3分析（DBP）。增加的启动被测量为线粒体对细胞增殖的敏感性增加。 与未处理的对照相比，处理的细胞对BH 3肽的反应。在过去的几年里，我们发现， DBP中药物引发的增加是人和小鼠模型中体内活性的极好预测因子， 实体瘤和液体瘤。DBP相对于大多数其他离体药物敏感性策略的重要优势是 DBP需要不超过24小时的离体培养。这克服了将军的主要障碍。 这类策略的应用，因为许多癌症不能适应长期离体培养，并且如果它们适应， 它们的表型发生改变，从而降低了它们所能提供的信息。我们正在探索DBP作为一种 发现工具和预测生物标志物在许多液体和实体肿瘤。此外，我们还将其作为一种工具， 确定可以使靶肿瘤细胞对免疫肿瘤学疗法更敏感的药物。

Summary I am an oncologist and cancer biologist supervising a laboratory focused on identifying therapies that selectively induce apoptosis in cancer cells. My initial contributions to the apoptosis field came with separating certain pro-death BCL-2 family BH3-only proteins into “sensitizers” and “activators” based on pro-apoptotic function. This finding drove my interest in the possibilities of inhibiting BCL-2 function with drugs that mimicked the BH3 domain of pro-apoptotic proteins. I designed the first mouse model that demonstrated that loss of BCL-2 function by itself could be sufficient to drive a cancer into remission. Following this, I designed a tool called BH3 profiling – exposing mitochondria to synthetic oligo-peptides based on the amphipathic alpha- helical BH3 domains of proapoptotic proteins and measuring mitochondrial outer membrane permeabilization (MOMP). By using certain selectively-interacting BH3 peptides, I could use BH3 profiling to identify cells that were especially sensitive to BH3 inhibition. I used BH3 profiling to help launch clinical trial programs of the BCL-2 inhibitor venetoclax in several diseases. Most successful among these so far have been programs in chronic lymphocytic leukemia and acute myelogenous leukemia, the former of which has already yielded FDA approvals. Using different BH3 peptides, BH3 profiling can measure overall apoptotic priming, or proximity to the threshold of apoptosis. We used this aspect to demonstrate that differential apoptotic priming is perhaps the most significant determinant of successful chemotherapy treatment. Moreover, differential apoptotic priming is the main reason that there is a therapeutic index for conventional chemotherapy – most non-malignant somatic cells are far less primed for apoptosis than chemosensitive cancer cells. Building on this finding, we asked whether we could identify drugs that could enhance apoptotic priming selectively in cancer cells. We found that we could measure increased apoptotic priming within hours of exposing cancer cells to effective drugs using dynamic BH3 profiling (DBP). Increased priming is measured as increased sensitivity of mitochondria in treated cells to BH3 peptides compared to untreated controls. Over the past few years, we have found that an increased priming by a drug in DBP is an excellent predictor of in vivo activity in human and mouse models, in solid and liquid tumors. An important advantage of DBP over most other ex vivo drug sensitivity strategies is that DBP requires no more than 24 hours of ex vivo culture. This overcomes the major obstacle to the general application of such strategies, since many cancers cannot adapt to long-term ex vivo culture, and if they do, they are phenotypically altered so as to degrade the information they can provide. We are exploring DBP as a discovery tool and predictive biomarker in many liquid and solid tumors. Moreover, we are using it as a tool to identify drugs that can make target tumor cells more sensitive to immuno-oncology therapies.