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 9

Mefloquine demonstrates therapeutic efficacy on AML cells growing in vivo.

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Mefloquine demonstrates therapeutic efficacy on AML cells growing in viv...
Sublethally irradiated SCID mice were injected subcutaneously with (A and B) OCI-AML2 or (C) K562 human leukemia cells or (D) MDAY-D2 mouse leukemia cells. Once tumors were palpable, mice were treated with 50 mg/kg mefloquine or vehicle control daily by oral gavage (n = 10 per condition). Tumor weight was measured at time of sacrifice. (E) Lysosome integrity (LysoTracker staining) in single-cell suspensions derived from control and mefloquine-treated OCI-AML2–derived tumors generated in xenografted mice. (F) Primary AML samples (2 × 106 cells) were injected intrafemorally into sublethally irradiated NOD/SCID mice (n = 20) and allowed to repopulate the mice for 2.5 weeks, as described in Methods. After this period, mice (n = 10 per treatment condition) were treated with 100 mg/kg/d by oral gavage for an additional 4.5 weeks and then sacrificed. Bone marrow from the non-injected femurs was collected; stained with anti-human antibodies to cell surface markers CD45, CD33, and CD19; and analyzed by flow cytometry. Data represent the percent CD45+ CD33+ CD19– human AML cells present in non-injected femurs. Serum bilirubin (G), alkaline phosphatase (H), aspartate transaminase (I), creatine kinase (J), creatinine (K), and mouse body weight (L) in vehicle- and mefloquine-treated mice (50 mg/kg × 21 days) (for serum markers of liver and kidney function, n = 3 per treatment condition; for body weight, n = 6 for controls and n = 5 for mefloquine-treated mice).