title: Darinaparsin is a multivalent chemotherapeutic which induces incomplete stress response with disruption of microtubules and Shh signaling.
abstract: Chemotherapeutics and other pharmaceuticals are common sources of cellular stress. Darinaparsin (ZIO-101) is a novel organic arsenical under evaluation as a cancer chemotherapeutic, but the drug's precise mechanism of action is unclear. Stress granule formation is an important cellular stress response, but the mechanisms of formation, maintenance, and dispersal of RNA-containing granules are not fully understood. During stress, small, diffuse granules initially form throughout the cytoplasm. These granules then coalesce near the nucleus into larger granules that disperse once the cellular stress is removed. Complete stress granule formation is dependent upon microtubules. Human cervical cancer (HeLa) cells, pre-treated with nocodazole for microtubule depolymerization, formed only small, diffuse stress granules upon sodium arsenite treatment. Darinaparsin, as a single agent, also induced the formation of small, diffuse stress granules, an effect similar to that of the combination of nocodazole with sodium arsenite. Darinaparsin inhibited the polymerization of microtubules both in vivo and in vitro. Interestingly, upon removal of darinaparsin, the small, diffuse stress granules completed formation with coalescence in the perinuclear region prior to disassembly. These results indicate that RNA stress granules must complete formation prior to disassembly, and completion of stress granule formation is dependent upon microtubules. Finally, treatment of cells with darinaparsin led to a reduction in Sonic hedgehog (Shh) stimulated activation of Gli1 and a loss of primary cilia. Therefore, darinaparsin represents a unique multivalent chemotherapeutic acting on stress induction, microtubule polymerization, and Shh signaling.
authors: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America.
authors: Twila A
authors: TA
authors: Mason
authors: Elena
authors: E
authors: Kolobova
authors: Jiang
authors: J
authors: Liu
authors: Joseph T
authors: JT
authors: Roland
authors: Chin
authors: C
authors: Chiang
authors: James R
authors: JR
authors: Goldenring
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001152:Arsenicals / Q000494:pharmacology*; D018053:Arsenites / Q000494:pharmacology; D002923:Cilia / Q000187:drug effects / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives* / Q000494:pharmacology; D006367:HeLa Cells; D053823:Hedgehog Proteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008870:Microtubules / Q000187:drug effects* / Q000378:metabolism*; D041681:NIH 3T3 Cells; D058105:Polymerization / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D017670:Sodium Compounds / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects*
chemical_list: D000970:Antineoplastic Agents; D001152:Arsenicals; D018053:Arsenites; D053823:Hedgehog Proteins; C509239:SHH protein, human; D017670:Sodium Compounds; C017947:sodium arsenite; C515055:darinaparsin; D005978:Glutathione