Targeting Aldehyde Dehydrogenase for Cancer Prevention

摘要： 在癌症中，树突状细胞和调节性T细胞中的乙醛脱氢酶(ALDH)酶活性很高， 假设是为了调节免疫反应，也是在癌症干细胞(CSCs)中，以帮助发展 复发性耐药病。因此，令人惊讶的是，针对ALDH的药物还没有开发成 在癌症中调节这些过程。为了研究这个问题，我们测试了现有的特定异构体的有效性。 和广谱ALDH抑制剂对培养细胞的作用，发现没有一种对细胞调节非常有效 生死存亡。此外，我们预测，由于重叠，将需要一种广谱抑制剂 ALDH家族成员的功能。这些观察结果为开发一种无毒的广泛的 光谱ALDH抑制剂，它将杀死ALDH+CSCs，以防止复发的耐药性疾病，并改善 黑色素瘤的免疫治疗。因此，中心假设是可以开发一种无毒的ALDH抑制剂 减少ALDH+CSCs介导的复发耐药病的发生并提高其疗效 现有的免疫疗法通过减少免疫抑制。初步数据显示，一种强有力的 无毒的ALDH抑制剂，建立在Isatin天然产品的主干上。此代理通过以下方式消除CSCs 高ALDH活性，防止传统药物治疗中常见的ALDH+细胞增加。最后， 该抑制剂改善同基因小鼠黑色素瘤模型中抗PD1免疫治疗的临床前疗效 在这种情况下，这种方法本身并不有效。基于这些支持假设的初步数据，以下是 提出了具体的目标。首先，确定一种无毒的广谱ALDH抑制剂的有效性 消除在接受传统化疗时扩大的黑色素瘤ALDH+CSC群体。 此外，确定其与传统化疗联合预防复发耐药的效力 疾病的发展。这将通过将ALDH+和ALDH-细胞群体从细胞系和 患者源性(PDX)肿瘤及其抑制物预防复发耐药病疗效的测定 在与当前临床相关的化疗相结合的情况下发展。最后， 将确定药剂组合抑制抗性的机理基础。第二，确定 无毒广谱ALDH抑制剂对肿瘤免疫调节和效应细胞的作用 微环境，单独和联合抗PD1抗体免疫治疗。针对特定目标 ALDH在黑色素瘤细胞和宿主细胞中的治疗效果将得到检验。机制导致了 将通过确定抑制物和抗体组合的影响来确定增强的免疫反应 对肿瘤内免疫细胞组成和功能的影响，评估免疫中相对ALDH水平 细胞群，并使用瞬时和遗传方法来靶向调节免疫细胞。这些 重大发现将证明靶向ALDH酶在癌症中调控的有效性 抵抗力和免疫细胞功能，为临床转化提供必要的临床前验证。

ABSTRACT: In cancer, aldehyde dehydrogenase (ALDH) enzyme activity is high in dendritic cells and regulatory T-cells, hypothesized to modulate the immune response and also in cancer stem cells (CSCs) to aid the development of recurrent resistant disease. It is therefore surprising that drugs targeting ALDH have not been developed to modulate these processes in cancer. To investigate this issue, we tested the efficacy of existing isoform-specific and broad-spectrum ALDH inhibitors on cultured cells and found that none were very effective at modulating cell survival. Furthermore, we predicted that a broad-spectrum inhibitor would be needed due to the overlapping functions of the ALDH family members. These observations provided the rationale to develop a non-toxic broad- spectrum ALDH inhibitor, which would kill ALDH+ CSCs to prevent recurrent resistant disease, and improve immunotherapy of melanoma. Thus, the central hypothesis is that a non-toxic ALDH inhibitor can be developed to reduce recurrent resistant disease development mediated by ALDH+ CSCs and improve the efficacy of existing immunotherapies by reducing immune suppression. Preliminary data show development of a potent non-toxic ALDH inhibitor built on the backbone of the Isatin natural product. This agent eliminates CSCs with high ALDH activity, preventing increases in ALDH+ cells typically seen with traditional drug treatments. Finally, the inhibitor improves the preclinical efficacy of anti-PD1 immunotherapy in a syngeneic mouse melanoma model where this approach alone is not effective. Based on these hypothesis-supporting preliminary data, the following Specific Aims are proposed. First, determine how effectively a non-toxic broad-spectrum ALDH inhibitor eliminates the melanoma ALDH+ CSC population that expands when treating with traditional chemotherapy. Furthermore, determine its potency when combined with traditional chemotherapy to prevent recurrent resistant disease development. This will be achieved by isolating ALDH+ and ALDH- cell populations from cell lines and patient derived (PDX) tumors and determining inhibitor efficacy for preventing recurrent resistant disease development when provided in combination with current clinically relevant chemotherapy. Finally, the mechanistic basis for inhibition of resistance by the agent combination will be identified. Second, determine the efficacy of a non-toxic broad-spectrum ALDH inhibitor on immune regulatory and effector cells in the tumor microenvironment, alone and when combined with anti-PD1 antibody immunotherapy. Specific targeting of ALDH in melanoma tumor cells and in host cells on therapeutic efficacy will be tested. Mechanisms leading to enhanced immune response will be identified by defining the impact of the inhibitor and antibody combinations on immune cell composition and function within the tumors, assessing the relative ALDH levels in the immune cell populations, and using transient and genetic approaches to target the modulating immune cells. These significant discoveries would demonstrate the efficacy of targeting ALDH enzymes in cancer for modulating resistance and immune cell function, providing needed preclinical validation necessary for clinical translation.