Aneel Paulus MD. MS1, Sharoon Akhtar MPhil1, Kelara

Identification of USP14 and UCHL5 as Druggable Oncotargets
in Ibrutinib-Resistant Mantle Cell Lymphoma
Aneel Paulus MD. MS , Sharoon Akhtar MPhil , Kelara Samuel , Hassan Yousaf MBBS , Davitte Cogen , Pooja Advani MD , Thomas Witzig MD3, George Weiner MD
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Sikander Ailawadhi MD , Joachim Gullbo MD. PhD , Stig Linder PhD , Geraldo Otero-Colon MD , Kasyapa Chitta PhD , Asher Chanan-Khan MD
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Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA; Division of Hematology and Oncology, Mayo Clinic, Jacksonville, FL USA; Department of Hematology and Internal Medicine, Mayo Clinic, Rochester, MN, USA
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Department of Internal Medicine and Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA, USA; Institute for Oncology-Pathology, Cancer Center Karolinska, Karolinska Institute, Stockholm, Sweden
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Introduction
• The clinical impact of ibrutinib is irrefutable and has been hailed
as a revolutionary treatment for several cancers, including mantle
cell lymphoma (MCL).
• Despite high response rates in MCL (ORR, 68%), ibrutinib yields l
ow complete responses and durability of remission is suboptimal
in MCL vs. CLL or Waldenstrom macroglobulinemia patients
(Cheah et al Ann Oncol 2015).
• Due to dismal survival of patients who relapse on ibrutinib,
identification of new oncotargets and development of novel
therapeutic strategies is paramount.
• Data suggests that ibrutinib-resistant MCL cells utilize alternative
pathways that render NFkB and associated signaling circuits
operational; which sustain cell survival.
• We have recently characterized the preclinical activity profile
of VLX1570, a novel first-in-class small molecule inhibitor of
the proteasome-associated deubiquitinating enzymes (DUBs),
USP14 and UCHL5, which directly inhibits NFkB gene activation
and signaling.
• This intriguing observation, prompted us to define the role of
USP14/UCHL5 and their inhibition in a diverse panel of B-cell
lymphoma cell lines, including MCL models as well as ibrutinibresistant MCL cells.
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Figure 1
Figure 3
Figure 6
Figure 7 (G and H)
Figure 10
Clinical Impact of Ibrutinib in B-Cell Cancers
Establishment and Characterization
of Ibrutinib-Resistant MCL Cells
VLX1570 Demonstrates in Vivo Activity
in an Ibrutinib-Insensitive Xenograft Model
USP14 and UCHL5 is Highly Expressed in B-Cell
Lymphomas, Including MCL
VLX1570 Downregulates Expression of CXCR4
and Cyclin1-D1 in MCL Cells
Figure 4
NFκB Directed Pathways Remain Operational
in Ibrutinib-Resistant MCL Cells
Hypothesis
Exposure of MCL cells to VLX1570 will result in tumor-specific
cell death, particularly in those cells resistant to ibrutinib
Figure 8
• Ibrutinib-resistant disease is associated with a very poor clinical outcome.
• Discovery of new targets in ibrutinib-resistant disease is warranted.
• We have recently identified USP14 and UCHL5 as novel, relevant and operational
oncotargets in MCL and ibrutinib-resistant MCL.
• VLX1570 is a novel drug for novel targets (USP14/UCHL5).
• Current investigations to build preclinical framework for testing of VLX1570 in MCL patients.
Figure 5
• Determine preclinical activity profile of VLX1570 in malignant
B-cells, including mantle cell lymphoma (MCL)
• Delineate whether VLX1570 activity is exhibited in ibrutinibresistant MCL cells.
• Conduct mechanistic analysis to determine pathways modified in
MCL cells by VLX1570
Figure 11
VLX1570 Specifically Binds to USP14 and UCHL5
and Inhibits Nfκb Signaling in Malignant B-Cells
VLX1570 and Ibrutinib Synergistically Kill
Ibrutinib-Resistant MCL Cells
Figure 9
VLX1570 induces robust apoptosis
in ibrutinib-resistant MCL cells
Materials & Methods
Critical questions…
• What are the mechanisms associated with ibrutinib resistance in MCL?
• What regulates these mechanisms?
• Can these mechanisms be targeted for therapeutic effect?
• USP14 and UCHL5 mRNA expression was queried through the Broad-Novartis CCLE
database and noted to be highest in B-cell/plasma cell cancer cell lines.
• Comparative gene expression analysis demonstrated USP14/UCHL5 prominence in DLBCL
and MCL cell lines.
• Amongst 25 B-cell cancer cell lines tested (comprising HL, DLBCL, MCL, WM, MM, Burkitt
lymphoma as well as certain drug resistant variants), MCL cell lines were most sensitive to
VLX1570 (USP14/UCHL5 inhibitor) with a median IC50 of 15.09 (range 7.45 – 24.03nM).
• VLX1570 induced dose-dependent loss in MCL cell viability- most notably in ibrutinibresistant MCL cells (Jeko/IR).
• Loss of MCL cell viability was mainly due to apoptotic cell death- significantly more
prominent in ibrutinib-resistant MCL cells (Jeko/IR).
• Mechanistic analysis revealed that VLX1570 engages its targets and modifies substrates
implicated in MCL pathogenesis such as CXCR4 and Cyclin-D1.
• VLX1570 was also tested in combination with ibrutinib in ibrutinib-resistant MCL cells
(Jeko/IR) and demonstrated pharmacologic synergy with ibrutinib in 6/9 combinations
tested (median combination index: 0.41).
Summary
USP14 and UCHL5 is Highly Expressed in B-Cell
Lymphomas, Including MCL
Ibrutinib Relapse is Associated with Dismal Outcome
Results
MCL Tumor Cells Are Most Sensitive To VLX1570
Figure 7 (A-F)
Figure 2
Objectives
VLX1570 (and its lab-grade analog, b-AP15) was obtained
from Vivolux AB and bortezomib from Sellekchem. Human NHL
(DLBCL, MCL, Burkitt), Hodgkin lymphoma (HL), multiple
myeloma (MM) cell lines as well as established drug-resistant
subclones were used in drug-sensitivity screening experiments
(total n=25).
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Acknowledgments
• Leukemia and Lymphoma Society (Chanan-Khan is a Leukemia and Lymphoma Scholar
in Clinical Research)
• Daniel Foundation of Alabama (Chanan-Khan)
• University of Iowa/Mayo Clinic Lymphoma SPORE Developmental Research program
(P50 CA097274, Paulus)
• Henry J. Predolin Foundation (Career Development Award, Paulus).
• We would also like to thank the Waterfall Waldenstrom Research Consortium for
their support.
COI
Stig Linder is an employee of Vivolux, Ab
© 2015 Mayo Foundation for Medical Education and Research