Date Published: January 09, 2018
Publisher: John Wiley and Sons Inc.
Author(s): Yang Wang, Xingyun Liao, Jianguo Sun, Bin Yi, Shenglin Luo, Tao Liu, Xu Tan, Dengqun Liu, Zelin Chen, Xin Wang, Chunmeng Shi.
The characterization of cancer stem‐like cells (CSCs) has profound implications for elucidating cancer biology and developing treatment strategies. Although surface markers are already used to identify CSCs, the expression of these markers is controversially linked to the phenotypes in different types of tumors and does not represent all functionally relevant of CSCs. Very recently, hyperactive HIF‐1α/glycolysis metabolic pathway is recognized as a master regulator of CSCs. In this study, a near‐infrared fluorescent small‐molecule, IR‐780, is identified for the exclusive characterization of human CSCs through the HIF‐1α/glycolysis dependent mitochondrial transporter ABCB10’s activity. The results identified for the first time that ABCB10 is involved in the preferential uptake of IR‐780 in CSCs, which is regulated by HIF‐1α via the direct interaction with the binding site of ABCB10 gene promoter region. In addition, IR‐780 is demonstrated to conjugate with anticancer drug 5‐fluorouracil to act as a potential drug delivery carrier for CSC‐targeted therapy. Thus, the studies provide a new rational approach independent of surface markers to characterize CSCs via small‐molecule‐based imaging of HIF‐1α/glycolysis hyperactive metabolic pathway dependent mitochondrial transporter’s activity, which holds promise for the further development of CSCs targeted diagnostic and therapeutic strategies.
Cancer is continuously to be the deadly disease worldwide and recent researches hypothesize that a small subset of cancer stem‐like cells (CSCs), behave like stem‐cells with self‐renewal capacity, are giving rise to heterogeneous hierarchical organization of cancer cells and responsible for disease recurrence and therapeutic resistance.1, 2 Thus, the characterization of the CSC population is critical to develop more specific therapeutic strategies for cancer treatment.3 Currently, the routine methods using displayed surface makers are widely applied to target and characterize CSCs in different types of tumors.4 However, the expressions of surface markers are controversial in different types of tumors, which may even cause conflicting results in different of researches.5 Further, the most commonly used isolation methods based on surface markers do not represent a general functionally relevant of the CSC population.6 Thus, alternative strategies based on CSC functional properties would have profound implications for the development of future CSCs‐targeted therapeutic strategies.
In summary, the identified NIR fluorescent small‐molecule, IR‐780, as a newly strategy for the characterization of CSCs has enormous advantages over the current CSCs‐targeted strategies. IR‐780 was demonstrated to preferentially uptake by the CSCs through the mitochondrial membrane transporter ABCB10, which was upregulated by HIF‐1α interacting with the binding sites of the ABCB10 gene promoter region. Thus, the NIR fluorescent imaging of mitochondrial transporter’s activity by IR‐780 is actually reflecting the metabolic features and HIF‐1α regulating pathway for the characterization of CSCs. In addition, IR‐780 was demonstrated to conjugate with 5‐FU and exhibited enhanced CSCs‐targeting therapeutic effects. Although more in‐depth studies are still needed to determine the CSCs‐targeting mechanisms, our studies have provided a reasonable approach, independent of surface markers, to characterize by imaging of the functional transporters’ activity, and provided a potential carrier for the delivery of anticancer drugs toward CSCs, which may hold significant promise for the further development of CSCs‐targeted therapeutic strategies.
Agents and Apparatus: Mito‐tracker Green and Lyso‐tracker Green were purchased from Molecular Probe. 2‐deoxy‐d‐glucose (2‐DG), oligomycin, and carbonylcyanide p‐trifluoromethoxy phenyl‐hydrazone (FCCP) were purchased from Sigma‐Aldrich. All the other chemicals and solvents with analytical grade were obtained from Aladdin Chemistry Reagent Company. 1H NMR, 13C NMR, and 19F NMR spectra were recorded on a Bruker 400 MHz spectrometer. HRMS was performed in a Bruker BioTOFIIIQ.
The authors declare no conflict of interest.