Identification of cytoskeleton-associated proteins essential for lysosomal stability and survival of human cancer cells.
Microtubule-disturbing drugs inhibit lysosomal trafficking and induce lysosomal membrane permeabilization followed by cathepsin-dependent cell death. To identify specific trafficking-related proteins that control cell survival and lysosomal stability, we screened a molecular motor siRNA library in human MCF7 breast cancer cells. SiRNAs targeting four kinesins (KIF11/Eg5, KIF20A, KIF21A, KIF25), myosin 1G (MYO1G), myosin heavy chain 1 (MYH1) and tropomyosin 2 (TPM2) were identified as effective inducers of non-apoptotic cell death. The cell death induced by KIF11, KIF21A, KIF25, MYH1 or TPM2 siRNAs was preceded by lysosomal membrane permeabilization, and all identified siRNAs induced several changes in the endo-lysosomal compartment, i.e. increased lysosomal volume (KIF11, KIF20A, KIF25, MYO1G, MYH1), increased cysteine cathepsin activity (KIF20A, KIF25), altered lysosomal localization (KIF25, MYH1, TPM2), increased dextran accumulation (KIF20A), or reduced autophagic flux (MYO1G, MYH1). Importantly, all seven siRNAs also killed human cervix cancer (HeLa) and osteosarcoma (U-2-OS) cells and sensitized cancer cells to other lysosome-destabilizing treatments, i.e. photo-oxidation, siramesine, etoposide or cisplatin. Similarly to KIF11 siRNA, the KIF11 inhibitor monastrol induced lysosomal membrane permeabilization and sensitized several cancer cell lines to siramesine. While KIF11 inhibitors are under clinical development as mitotic blockers, our data reveal a new function for KIF11 in controlling lysosomal stability and introduce six other molecular motors as putative cancer drug targets.
Cell Death and Metabolism, Danish Cancer Society Research Center, Copenhagen, Denmark.
Line
L
Groth-Pedersen
Sonja
S
Aits
Elisabeth
E
Corcelle-Termeau
Nikolaj H T
NH
Petersen
Jesper
J
Nylandsted
Marja
M
Jäättelä
D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects; D001943:Breast Neoplasms / Q000473:pathology*; D016923:Cell Death / Q000187:drug effects*; D002463:Cell Membrane Permeability / Q000187:drug effects; D003598:Cytoskeletal Proteins / Q000502:physiology*; D005260:Female; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins / Q000037:antagonists & inhibitors / Q000502:physiology; D008247:Lysosomes / Q000187:drug effects*; D015778:Minor Histocompatibility Antigens / Q000502:physiology; D009218:Myosins / Q000502:physiology; D011743:Pyrimidines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D013871:Thiones / Q000494:pharmacology; D014335:Tropomyosin / Q000502:physiology
D003598:Cytoskeletal Proteins; C470243:KIF11 protein, human; C440608:MYO1G protein, human; D015778:Minor Histocompatibility Antigens; D011743:Pyrimidines; D034741:RNA, Small Interfering; C518659:TPM2 protein, human; D013871:Thiones; D014335:Tropomyosin; C400223:monastrol; D009218:Myosins; D016547:Kinesins