NOTCH-induced aldehyde dehydrogenase 1A1 deacetylation promotes breast cancer stem cells
Di Zhao, … , Kun-Liang Guan, Qun-Ying Lei
Di Zhao, … , Kun-Liang Guan, Qun-Ying Lei
Published November 10, 2014
Citation Information: J Clin Invest. 2014;124(12):5453-5465. https://doi.org/10.1172/JCI76611.
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Research Article Oncology

NOTCH-induced aldehyde dehydrogenase 1A1 deacetylation promotes breast cancer stem cells

Abstract

High aldehyde dehydrogenase (ALDH) activity is a marker commonly used to isolate stem cells, particularly breast cancer stem cells (CSCs). Here, we determined that ALDH1A1 activity is inhibited by acetylation of lysine 353 (K353) and that acetyltransferase P300/CBP–associated factor (PCAF) and deacetylase sirtuin 2 (SIRT2) are responsible for regulating the acetylation state of ALDH1A1 K353. Evaluation of breast carcinoma tissues from patients revealed that cells with high ALDH1 activity have low ALDH1A1 acetylation and are capable of self-renewal. Acetylation of ALDH1A1 inhibited both the stem cell population and self-renewal properties in breast cancer. Moreover, NOTCH signaling activated ALDH1A1 through the induction of SIRT2, leading to ALDH1A1 deacetylation and enzymatic activation to promote breast CSCs. In breast cancer xenograft models, replacement of endogenous ALDH1A1 with an acetylation mimetic mutant inhibited tumorigenesis and tumor growth. Together, the results from our study reveal a function and mechanism of ALDH1A1 acetylation in regulating breast CSCs.

Authors

Di Zhao, Yan Mo, Meng-Tian Li, Shao-Wu Zou, Zhou-Li Cheng, Yi-Ping Sun, Yue Xiong, Kun-Liang Guan, Qun-Ying Lei

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Figure 7

Mutation of the K353 acetylation site in ALDH1A1 inhibits NOTCH signaling to promote breast CSCs.

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Mutation of the K353 acetylation site in ALDH1A1 inhibits NOTCH signalin...
(A and B) Inhibition of NOTCH signaling reduced ALDH1+ cell populations and mammosphere formation. MDA-MB-468 cells were treated with 20 μM DAPT, followed by ALDEFLUOR assay (A) and mammosphere-forming assay (B). (C and D) Activation of the NOTCH signaling pathway promoted breast CSCs. MDA-MB-468 cells were treated with 10 nM DLL4, followed by ALDEFLUOR assay (C) and mammosphere-forming assay (D). (E) NOTCH inhibitor treatment enhanced K353 acetylation and decreased ALDH1+ cell populations in vivo. Xenografting into mammary fat pads was performed using 104 MDA-MB-468 cells, and xenograft tumors were treated with DAPT (20 mg/kg/mouse) every week. After 6 weeks, ALDH1A1, K353 acetylation, and ALDH1+ cell populations in tumors were analyzed. (F) K353R/Q mutation blocked the effect of the NOTCH signaling pathway on mammosphere formation. MDA-MB-468 cells reexpressing ALDH1A1WT, ALDH1A1K353R, and ALDH1A1K353Q mutants were treated with DAPT or DLL4 at the indicated concentrations, and mammosphere formation was measured. Data represent the mean ± SD of triplicate experiments for relative ALDH1+ cell populations and number of mammospheres per 10,000 transplanted cells.