Lysosomal disruption preferentially targets acute myeloid leukemia cells and progenitors
Mahadeo A. Sukhai, … , Guri Giaever, Aaron D. Schimmer
Mahadeo A. Sukhai, … , Guri Giaever, Aaron D. Schimmer
Published December 3, 2012
Citation Information: J Clin Invest. 2013;123(1):315-328. https://doi.org/10.1172/JCI64180.
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Research Article Oncology

Lysosomal disruption preferentially targets acute myeloid leukemia cells and progenitors

Abstract

Despite efforts to understand and treat acute myeloid leukemia (AML), there remains a need for more comprehensive therapies to prevent AML-associated relapses. To identify new therapeutic strategies for AML, we screened a library of on- and off-patent drugs and identified the antimalarial agent mefloquine as a compound that selectively kills AML cells and AML stem cells in a panel of leukemia cell lines and in mice. Using a yeast genome-wide functional screen for mefloquine sensitizers, we identified genes associated with the yeast vacuole, the homolog of the mammalian lysosome. Consistent with this, we determined that mefloquine disrupts lysosomes, directly permeabilizes the lysosome membrane, and releases cathepsins into the cytosol. Knockdown of the lysosomal membrane proteins LAMP1 and LAMP2 resulted in decreased cell viability, as did treatment of AML cells with known lysosome disrupters. Highlighting a potential therapeutic rationale for this strategy, leukemic cells had significantly larger lysosomes compared with normal cells, and leukemia-initiating cells overexpressed lysosomal biogenesis genes. These results demonstrate that lysosomal disruption preferentially targets AML cells and AML progenitor cells, providing a rationale for testing lysosomal disruption as a novel therapeutic strategy for AML.

Authors

Mahadeo A. Sukhai, Swayam Prabha, Rose Hurren, Angela C. Rutledge, Anna Y. Lee, Shrivani Sriskanthadevan, Hong Sun, Xiaoming Wang, Marko Skrtic, Ayesh Seneviratne, Maria Cusimano, Bozhena Jhas, Marcela Gronda, Neil MacLean, Eunice E. Cho, Paul A. Spagnuolo, Sumaiya Sharmeen, Marinella Gebbia, Malene Urbanus, Kolja Eppert, Dilan Dissanayake, Alexia Jonet, Alexandra Dassonville-Klimpt, Xiaoming Li, Alessandro Datti, Pamela S. Ohashi, Jeff Wrana, Ian Rogers, Pascal Sonnet, William Y. Ellis, Seth J. Corey, Connie Eaves, Mark D. Minden, Jean C.Y. Wang, John E. Dick, Corey Nislow, Guri Giaever, Aaron D. Schimmer

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Figure 6

Genetic and chemical strategies to disrupt lysosomes have antileukemia effects.

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Genetic and chemical strategies to disrupt lysosomes have antileukemia e...
(A) Left: Mean ± SD change in LAMP1 mRNA compared with untransduced controls after shRNA-mediated knockdown of LAMP1 (*P < 0.05). Right: LAMP1 and actin protein expression after shRNA-mediated knockdown. Molecular weights (kDa) are indicated. (B) Left: Mean ± SD change in LAMP2 mRNA compared with untransduced controls after shRNA-mediated knockdown of LAMP2 (*P < 0.05). Right: LAMP2 protein expression in isolated lysosomes after shRNA-mediated knockdown. Molecular weights (kDa) are indicated. Asterisk indicates nonspecific band. Equal protein loading was confirmed by Ponceau S staining. (C) Number of viable OCI-AML2 cells by trypan blue staining after shRNA-mediated knockdown of LAMP1, LAMP2, or control sequences. Data represent mean ± SD number of viable cells from 4 replicates in a representative experiment. (D) Mean ± SD lysosome integrity (acridine orange staining), ROS production (carboxy-H2DCFDA staining), and sensitivity to 8 μM mefloquine (MTS assay) after shRNA-mediated knockdown of LAMP1. Mean ± SD lysosome integrity (24 hours, LysoTracker staining) (E) and viability (48 hours, Annexin V staining) (F) in OCI-AML2 cells treated with LeuLeuOMe. (G) Mean ± SD lysosome integrity (LysoTracker staining) in TEX cells treated for 16 hours with 5 μM artesunate or artenimol. (H) Mean ± SD percent inhibition of clonogenic growth of primary AML and normal hematopoietic cells pretreated with 5 μM artesunate for 48 hours and then plated in clonogenic growth assays (*P < 0.05).