FBW7-Dependent Mcl-1 Degradation Mediates the Anticancer Effect of Hsp90 Inhibitors

Heat shock protein 90 (Hsp90) is widely overexpressed in cancer cells and necessary for maintenance of malignant phenotypes. Hsp90 inhibition induces tumor cell death through degradation of its client oncoproteins and has shown promises in preclinical studies. However, the mechanism by which Hsp90 inhibitors kill tumor cells is not well-understood. Biomarkers associated with differential sensitivity and resistance to Hsp90 inhibitors remain to be identified. In this study, we found that colorectal cancer cells containing inactivating mutations of FBW7, a tumor suppressor and E3 ubiquitin ligase, are intrinsically insensitive to Hsp90 inhibitors. The insensitive colorectal cancer cells lack degradation of Mcl-1, a prosurvival Bcl-2 family protein. Hsp90 inhibition promotes GSK3β-dependent phosphorylation of Mcl-1, which subsequently binds to FBW7 and undergoes ubiquitination and proteasomal degradation. Specifically blocking Mcl-1 phosphorylation by genetic knock-in abrogates its degradation and renders in vitro and in vivo resistance to Hsp90 inhibitors, which can be overcame by Mcl-1–selective small-molecule inhibitors. Collectively, our findings demonstrate a key role of GSK3β/FBW7-dependent Mcl-1 degradation in killing of colorectal cancer cells by Hsp90 inhibitors and suggest FBW7 mutational status as a biomarker for Hsp90-targeted therapy. Mol Cancer Ther; 16(9); 1979–88. ©2017 AACR.

[1]  Jian Yu,et al.  Mcl-1 Degradation Is Required for Targeted Therapeutics to Eradicate Colon Cancer Cells. , 2017, Cancer research.

[2]  A. Strasser,et al.  The MCL1 inhibitor S63845 is tolerable and effective in diverse cancer models , 2016, Nature.

[3]  Jian Yu,et al.  FBW7 mutations mediate resistance of colorectal cancer to targeted therapies by blocking Mcl-1 degradation , 2016, Oncogene.

[4]  A. Venditti,et al.  Venetoclax: Bcl-2 inhibition for the treatment of chronic lymphocytic leukemia. , 2016, Drugs of today.

[5]  P. Workman,et al.  Maximizing the Therapeutic Potential of HSP90 Inhibitors , 2015, Molecular Cancer Research.

[6]  S. Fulda.  Targeting apoptosis for anticancer therapy. , 2015, Seminars in cancer biology.

[7]  R. Dobrowsky,et al.  Hsp90 C-Terminal Inhibitors Exhibit Antimigratory Activity by Disrupting the Hsp90α/Aha1 Complex in PC3-MM2 Cells , 2014, ACS chemical biology.

[8]  B. Clurman,et al.  Tumor suppression by the Fbw7 ubiquitin ligase: mechanisms and opportunities. , 2014, Cancer cell.

[9]  S. Desagher,et al.  Mcl-1 Ubiquitination: Unique Regulation of an Essential Survival Protein , 2014, Cells.

[10]  P. Workman,et al.  E3 ubiquitin ligase Cullin-5 modulates multiple molecular and cellular responses to heat shock protein 90 inhibition in human cancer cells , 2014, Proceedings of the National Academy of Sciences.

[11]  T. Cierpicki,et al.  3-Substituted-N-(4-Hydroxynaphthalen-1-yl)arylsulfonamides as a Novel Class of Selective Mcl-1 Inhibitors: Structure-Based Design, Synthesis, SAR, and Biological Evaluation , 2014, Journal of medicinal chemistry.

[12]  Tao Zhang,et al.  A Novel Small-Molecule Inhibitor of Mcl-1 Blocks Pancreatic Cancer Growth In Vitro and In Vivo , 2013, Molecular Cancer Therapeutics.

[13]  Jian Yu,et al.  Hsp90 Inhibitors Promote p53-Dependent Apoptosis through PUMA and Bax , 2013, Molecular Cancer Therapeutics.

[14]  M. Butterworth,et al.  Evaluation and critical assessment of putative MCL-1 inhibitors , 2013, Cell Death and Differentiation.

[15]  R. Kurzrock,et al.  Targeting the molecular chaperone heat shock protein 90 (HSP90): lessons learned and future directions. , 2013, Cancer treatment reviews.

[16]  U. McDermott,et al.  Mcl-1 and FBW7 control a dominant survival pathway underlying HDAC and Bcl-2 inhibitor synergy in squamous cell carcinoma. , 2013, Cancer discovery.

[17]  Jian Yu,et al.  Targeting Bax interaction sites reveals that only homo-oligomerization sites are essential for its activation , 2013, Cell Death and Differentiation.

[18]  Xiangyi Lu,et al.  Hsp90 inhibitors and drug resistance in cancer: the potential benefits of combination therapies of Hsp90 inhibitors and other anti-cancer drugs. , 2012, Biochemical pharmacology.

[19]  Paul Workman,et al.  Hsp90 Molecular Chaperone Inhibitors: Are We There Yet? , 2012, Clinical Cancer Research.

[20]  Jian Yu,et al.  Inhibiting oncogenic signaling by sorafenib activates PUMA via GSK3β and NF-κB to suppress tumor cell growth , 2011, Oncogene.

[21]  Alison Stopeck,et al.  HSP90 Inhibition Is Effective in Breast Cancer: A Phase II Trial of Tanespimycin (17-AAG) Plus Trastuzumab in Patients with HER2-Positive Metastatic Breast Cancer Progressing on Trastuzumab , 2011, Clinical Cancer Research.

[22]  U. Moll,et al.  Blockade of Hsp90 by 17AAG antagonizes MDMX and synergizes with Nutlin to induce p53-mediated apoptosis in solid tumors , 2011, Cell Death and Disease.

[23]  D. Hanahan,et al.  Hallmarks of Cancer: The Next Generation , 2011, Cell.

[24]  Adam R. Johnson,et al.  Sensitivity to antitubulin chemotherapeutics is regulated by MCL1 and FBW7 , 2011, Nature.

[25]  Susan Lindquist,et al.  Hsp90 and Environmental Stress Transform the Adaptive Value of Natural Genetic Variation , 2010, Science.

[26]  A. Iafrate,et al.  Activity of IPI-504, a novel heat-shock protein 90 inhibitor, in patients with molecularly defined non-small-cell lung cancer. , 2010, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[27]  T. Yeatman,et al.  Correlation between Mcl-1 and pAKT protein expression in colorectal cancer. , 2010, International journal of clinical and experimental pathology.

[28]  S. Edwards,et al.  Mcl‐1; the molecular regulation of protein function , 2010, FEBS letters.

[29]  F. Bazan,et al.  Deubiquitinase USP9X stabilizes MCL1 and promotes tumour cell survival , 2010, Nature.

[30]  F. Zindy,et al.  Inhibition of Hsp90 via 17-DMAG induces apoptosis in a p53-dependent manner to prevent medulloblastoma , 2009, Proceedings of the National Academy of Sciences.

[31]  G. Morgan,et al.  Heat shock protein inhibition is associated with activation of the unfolded protein response pathway in myeloma plasma cells. , 2007, Blood.

[32]  Rob Pieters,et al.  FBW7 mutations in leukemic cells mediate NOTCH pathway activation and resistance to γ-secretase inhibitors , 2007, The Journal of experimental medicine.

[33]  M. Hung,et al.  Degradation of Mcl-1 by β-TrCP Mediates Glycogen Synthase Kinase 3-Induced Tumor Suppression and Chemosensitization , 2006, Molecular and Cellular Biology.

[34]  D. Green,et al.  Glycogen synthase kinase-3 regulates mitochondrial outer membrane permeabilization and apoptosis by destabilization of MCL-1. , 2006, Molecular cell.

[35]  Jun Qin,et al.  Erk Associates with and Primes GSK-3β for Its Inactivation Resulting in Upregulation of β-Catenin , 2005 .

[36]  Xiaodong Wang,et al.  Mule/ARF-BP1, a BH3-Only E3 Ubiquitin Ligase, Catalyzes the Polyubiquitination of Mcl-1 and Regulates Apoptosis , 2005, Cell.

[37]  Carlo Rago,et al.  Inactivation of hCDC4 can cause chromosomal instability , 2004, Nature.

[38]  S. Korsmeyer,et al.  Cell Death Critical Control Points , 2004, Cell.

[39]  P. O'dwyer,et al.  Additive interaction of oxaliplatin and 17-allylamino-17-demethoxygeldanamycin in colon cancer cell lines results from inhibition of nuclear factor kappaB signaling. , 2003, Cancer research.

[40]  L. Fritz,et al.  A high-affinity conformation of Hsp90 confers tumour selectivity on Hsp90 inhibitors , 2003, Nature.

[41]  N. Rosen,et al.  Degradation of HER2 by ansamycins induces growth arrest and apoptosis in cells with HER2 overexpression via a HER3, phosphatidylinositol 3'-kinase-AKT-dependent pathway. , 2002, Cancer research.

[42]  P. Workman,et al.  Inhibition of signal transduction by the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin results in cytostasis and apoptosis. , 2001, Cancer research.

[43]  J W Yates,et al.  Selective small molecule inhibitors of glycogen synthase kinase-3 modulate glycogen metabolism and gene transcription. , 2000, Chemistry & biology.

[44]  B. Blagg,et al.  Anticancer Inhibitors of Hsp90 Function: Beyond the Usual Suspects. , 2016, Advances in cancer research.

[45]  S. Fesik,et al.  Small molecule Mcl-1 inhibitors for the treatment of cancer. , 2015, Pharmacology & therapeutics.

[46]  Y. Joo,et al.  Myeloid cell leukemia-1 is associated with tumor progression by inhibiting apoptosis and enhancing angiogenesis in colorectal cancer. , 2015, American journal of cancer research.

[47]  Yonghong Xiao,et al.  SCFFBW 7 regulates cellular apoptosis by targeting MCL 1 for ubiquitylation and destruction , 2011 .

[48]  A. Strasser,et al.  The BCL-2 protein family: opposing activities that mediate cell death , 2008, Nature Reviews Molecular Cell Biology.

[49]  Jun Qin,et al.  Erk associates with and primes GSK-3beta for its inactivation resulting in upregulation of beta-catenin. , 2005, Molecular cell.