title: Characterization of the loss of SUMO pathway function on cancer cells and tumor proliferation.
abstract: SUMOylation is a post-translational ubiquitin-like protein modification pathway that regulates important cellular processes including chromosome structure, kinetochore function, chromosome segregation, nuclear and sub-nuclear organization, transcription and DNA damage repair. There is increasing evidence that the SUMO pathway is dysregulated in cancer, raising the possibility that modulation of this pathway may have therapeutic potential. To investigate the importance of the SUMO pathway in the context of cancer cell proliferation and tumor growth, we applied lentivirus-based short hairpin RNAs (shRNA) to knockdown SUMO pathway genes in human cancer cells. shRNAs for SAE2 and UBC9 reduced SUMO conjugation activity and inhibited proliferation of human cancer cells. To expand upon these observations, we generated doxycycline inducible conditional shRNA cell lines for SAE2 to achieve acute and reversible SAE2 knockdown. Conditional SAE2 knockdown in U2OS and HCT116 cells slowed cell growth in vitro, and SAE2 knockdown induced multiple terminal outcomes including apoptosis, endoreduplication and senescence. Multinucleated cells became senescent and stained positive for the senescence marker, SA-β Gal, and displayed elevated levels of p53 and p21. In an attempt to explain these phenotypes, we confirmed that loss of SUMO pathway activity leads to a loss of SUMOylated Topoisomerase IIα and the appearance of chromatin bridges which can impair proper cytokinesis and lead to multinucleation. Furthermore, knockdown of SAE2 induces disruption of PML nuclear bodies which may further promote apoptosis or senescence. In an in vivo HCT116 xenograft tumor model, conditional SAE2 knockdown strongly impaired tumor growth. These data demonstrate that the SUMO pathway is required for cancer cell proliferation in vitro and tumor growth in vivo, implicating the SUMO pathway as a potential cancer therapeutic target.
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: Xingyue
authors: X
authors: He
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: Jessica
authors: J
authors: Riceberg
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: Sai M
authors: SM
authors: Pulukuri
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: Steve
authors: S
authors: Grossman
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: Vaishali
authors: V
authors: Shinde
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: Pooja
authors: P
authors: Shah
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: James E
authors: JE
authors: Brownell
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: Larry
authors: L
authors: Dick
authors: Oncology Drug Discovery Unit, Takeda Pharmaceuticals International Co., Cambridge, United States of America.
authors: John
authors: J
authors: Newcomb
authors: Nurix, Inc. San Francisco, United States of America.
authors: Neil
authors: N
authors: Bence
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics; D059447:Cell Cycle Checkpoints / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016922:Cellular Senescence / Q000235:genetics; D004195:Disease Models, Animal; D055785:Gene Knockdown Techniques; D064593:Heterografts; D006801:Humans; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D010641:Phenotype; D034622:RNA Interference; D015398:Signal Transduction; D025841:Small Ubiquitin-Related Modifier Proteins / Q000235:genetics / Q000378:metabolism*; D058207:Sumoylation; D047368:Tumor Burden / Q000235:genetics
chemical_list: D025841:Small Ubiquitin-Related Modifier Proteins