Department of Chemistry, University of Illinois Urbana-Champaign; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign; Cancer Center of Illinois, University of Illinois Urbana-Champaign.
Department of Biochemistry, University of Illinois Urbana-Champaign; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign; Cancer Center of Illinois, University of Illinois Urbana-Champaign.
J Vis Exp. 2023 Mar 31(193). doi: 10.3791/64713.
Relapse after cancer treatment is often attributed to the persistence of a subpopulation of tumor cells known as cancer stem cells (CSCs), which are characterized by their remarkable tumor-initiating and self-renewal capacity. Depending on the origin of the tumor (e.g., ovaries), the CSC surface biomarker profile can vary dramatically, making the identification of such cells via immunohistochemical staining a challenging endeavor. On the contrary, aldehyde dehydrogenase 1A1 (ALDH1A1) has emerged as an excellent marker to identify CSCs, owing to its conserved expression profile in nearly all progenitor cells including CSCs. The ALDH1A1 isoform belongs to a superfamily of 19 enzymes that are responsible for the oxidation of various endogenous and xenobiotic aldehydes to the corresponding carboxylic acid products. Chan et al. recently developed AlDeSense, an isoform-selective "turn-on" probe for the detection of ALDH1A1 activity, as well as a non-reactive matching control reagent (Ctrl-AlDeSense) to account for off-target staining. This isoform-selective tool has already been demonstrated to be a versatile chemical tool through the detection of ALDH1A1 activity in K562 myelogenous leukemia cells, mammospheres, and melanoma-derived CSC xenografts. In this article, the utility of the probe was showcased through additional fluorimetry, confocal microscopy, and flow cytometry experiments where the relative ALDH1A1 activity was determined in a panel of five ovarian cancer cell lines.
癌症治疗后的复发通常归因于肿瘤细胞亚群的持续存在，这些细胞被称为癌症干细胞 (CSCs)，其特征是具有显著的肿瘤起始和自我更新能力。根据肿瘤的起源（例如卵巢），CSC 表面生物标志物谱可能会有很大差异，因此通过免疫组织化学染色来识别这些细胞是一项具有挑战性的工作。相反，醛脱氢酶 1A1 (ALDH1A1) 已成为识别 CSCs 的优秀标志物，因为它在几乎所有祖细胞（包括 CSCs）中都具有保守的表达谱。ALDH1A1 同工酶属于 19 种酶的超家族，负责氧化各种内源性和外源性醛为相应的羧酸产物。Chan 等人最近开发了一种同工酶选择性“开启”探针 AlDeSense，用于检测 ALDH1A1 活性，以及一种非反应性匹配对照试剂 (Ctrl-AlDeSense)，以解释非靶标染色。这种同工酶选择性工具已经通过在 K562 髓样白血病细胞、乳腺球体和黑色素瘤衍生的 CSC 异种移植中检测 ALDH1A1 活性，证明是一种多功能化学工具。在本文中，通过额外的荧光法、共聚焦显微镜和流式细胞术实验展示了该探针的实用性，在 5 种卵巢癌细胞系中确定了相对 ALDH1A1 活性。
