Opposing effects of cancer-type-specific SPOP mutants on BET protein degradation and sensitivity to BET inhibitors.
Janouskova HInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
El Tekle GInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Bellini EInstitute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
Udeshi NDBroad Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
Rinaldi AInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Ulbricht ADepartment of Biochemistry, Eidgenössische Technische Hochschule, Zurich, Switzerland.
Bernasocchi TInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Civenni GInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Losa MInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Svinkina TBroad Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
Bielski CMBroad Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
Kryukov GVBroad Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
Cascione LInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Napoli SInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Enchev RIDepartment of Biochemistry, Eidgenössische Technische Hochschule, Zurich, Switzerland.
Mutch DGDivision of Gynecologic Oncology, Washington University, St. Louis, Missouri, USA.
Carney MEDepartment of Obstetrics, Gynecology and Women’s Health, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
Berchuck ADivision of Gynecologic Oncology, Duke Cancer Center, Durham, North Carolina, USA.
Winterhoff BJNDivision of Gynecologic Oncology, University of Minnesota, Minneapolis, Minnesota, USA.
Broaddus RRDepartment of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Schraml PInstitute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
Moch HInstitute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
Bertoni FInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Catapano CVInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
Peter MDepartment of Biochemistry, Eidgenössische Technische Hochschule, Zurich, Switzerland.
Carr SADepartment of Biochemistry, Eidgenössische Technische Hochschule, Zurich, Switzerland.
Garraway LABroad Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
Wild PJInstitute of Surgical Pathology, University Hospital Zurich, Zurich, Switzerland
Theurillat JPInstitute of Oncology Research, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
English
It is generally assumed that recurrent mutations within a given cancer driver gene elicit similar drug responses. Cancer genome studies have identified recurrent but divergent missense mutations affecting the substrate-recognition domain of the ubiquitin ligase adaptor SPOP in endometrial and prostate cancers. The therapeutic implications of these mutations remain incompletely understood. Here we analyzed changes in the ubiquitin landscape induced by endometrial cancer-associated SPOP mutations and identified BRD2, BRD3 and BRD4 proteins (BETs) as SPOP-CUL3 substrates that are preferentially degraded by endometrial cancer-associated SPOP mutants. The resulting reduction of BET protein levels sensitized cancer cells to BET inhibitors. Conversely, prostate cancer-specific SPOP mutations resulted in impaired degradation of BETs, promoting their resistance to pharmacologic inhibition. These results uncover an oncogenomics paradox, whereby mutations mapping to the same domain evoke opposing drug susceptibilities. Specifically, we provide a molecular rationale for the use of BET inhibitors to treat patients with endometrial but not prostate cancer who harbor SPOP mutations.