The E3 ligase APC/C(Cdh1) promotes ubiquitylation-mediated proteolysis of PAX3 to suppress melanocyte proliferation and melanoma growth.
The anaphase-promoting complex or cyclosome with the subunit Cdh1 (APC/C(Cdh1)) is an E3 ubiquitin ligase involved in the control of the cell cycle. Here, we identified sporadic mutations occurring in the genes encoding APC components, including Cdh1, in human melanoma samples and found that loss of APC/C(Cdh1) may promote melanoma development and progression, but not by affecting cell cycle regulatory targets of APC/C. Most of the mutations we found in CDH1 were those associated with ultraviolet light (UV)-induced melanomagenesis. Compared with normal human skin tissue and human or mouse melanocytes, the abundance of Cdh1 was decreased and that of the transcription factor PAX3 was increased in human melanoma tissue and human or mouse melanoma cell lines, respectively; Cdh1 abundance was further decreased with advanced stages of human melanoma. PAX3 was a substrate of APC/C(Cdh1) in melanocytes, and APC/C(Cdh1)-mediated ubiquitylation marked PAX3 for proteolytic degradation in a manner dependent on the D-box motif in PAX3. Either mutating the D-box in PAX3 or knocking down Cdh1 prevented the ubiquitylation and degradation of PAX3 and increased proliferation and melanin production in melanocytes. Knocking down Cdh1 in melanoma cells in culture or before implantation in mice promoted doxorubicin resistance, whereas reexpressing wild-type Cdh1, but not E3 ligase-deficient Cdh1 or a mutant that could not interact with PAX3, restored doxorubicin sensitivity in melanoma cells both in culture and in xenografts. Thus, our findings suggest a tumor suppressor role for APC/C(Cdh1) in melanocytes and that targeting PAX3 may be a strategy for treating melanoma.
Department of Pharmacology and Experimental Therapeutics, Boston University Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA.
Juxiang
J
Cao
Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
Xiangpeng
X
Dai
Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
Lixin
L
Wan
Department of Pharmacology and Experimental Therapeutics, Boston University Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA. Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 20032, P. R. China.
Hongshen
H
Wang
Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
Jinfang
J
Zhang
Molecular Cell Sciences Research Centre, Canadian Cancer Society Research Institute, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
Philip S
PS
Goff
Molecular Cell Sciences Research Centre, Canadian Cancer Society Research Institute, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
Elena V
EV
Sviderskaya
Department of Molecular and Cell Biology, The University of Texas at Dallas, Dallas, TX 75080, USA.
Zhenyu
Z
Xuan
Division of Hematology and Oncology, Department of Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35233, USA.
Zhixiang
Z
Xu
Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Xiaowei
X
Xu
Department of Developmental, Molecular and Chemical Biology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA.
Philip
P
Hinds
Cancer Center, Massachusetts General Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02114, USA.
Keith T
KT
Flaherty
Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA.
Douglas V
DV
Faller
Ludwig Institute for Cancer Research, University of Oxford, Headington, Oxford OX3 7DQ, UK.
Colin R
CR
Goding
Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 20032, P. R. China. yjwang88@hotmail.com wwei@bidmc.harvard.edu rutaocui@bu.edu.
Yongjun
Y
Wang
Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA. yjwang88@hotmail.com wwei@bidmc.harvard.edu rutaocui@bu.edu.
Wenyi
W
Wei
Department of Pharmacology and Experimental Therapeutics, Boston University Cancer Center, Boston University School of Medicine, Boston, MA 02118, USA. Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 20032, P. R. China. yjwang88@hotmail.com wwei@bidmc.harvard.edu rutaocui@bu.edu.
Rutao
R
Cui
D000818:Animals; D064189:Apc1 Subunit, Anaphase-Promoting Complex-Cyclosome / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D008544:Melanocytes / Q000378:metabolism* / Q000473:pathology; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis
C577335:ANAPC1 protein, human; C577336:Anapc1 protein, mouse; D064189:Apc1 Subunit, Anaphase-Promoting Complex-Cyclosome; D009363:Neoplasm Proteins; D000072041:PAX3 Transcription Factor; C489409:PAX3 protein, human; D051761:Paired Box Transcription Factors; C068686:Pax3 protein, mouse