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CONTEXT SPECIFIC ROLE OF DEUBIQUITYLASE ENZYME, USP9X, IN HEAD AND NECK CANCER Devathri Nanayakkara Eskitis Institute for Drug Discovery Griffith University
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Head and neck cancer
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Sixth most common cancer
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Head and neck cancer Sixth most common cancer Five year survival rate after diagnosis, 50%
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Head and neck cancer Sixth most common cancer Five year survival rate after diagnosis, 50% Drug resistance Early tumors - asymptomatic
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Head and neck cancer Sixth most common cancer Five year survival rate after diagnosis, 50% Drug resistance Early tumors - asymptomatic “Need to study the underlying molecular pathways unveiling potential detection markers and drug targets”
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In a recent study, Characterized the somatic mutation landscape of OSCC-GB
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- Found Five new genes associated with OSCC-GB
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-Among them was USP9X -22% harboured copy number loss and truncating mutations -Role as tumor suppressor
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USP9X Deubiquitylating enzyme – Family of cysteine and metalloproteases
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USP9X Deubiquitylating enzyme – Family of cysteine and metalloproteases http://legacy.butler.edu/biology/faculty-staff/research-interests/jkowalski/research-in-the-kowalski-lab/
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Murtaza et al, 2015
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USP9X in cancer
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Breast cancer Colorectal cancer Bladder cancer Oral cancer Brain cancer Pancreatic cancer Prostate cancer Lung cancer Lymphoma
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In this study, Aims : To evaluate the role of USP9X in an in vitro system To elucidate the molecular mechanisms USP9X is involved in
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How? In vitro cell lines – SCC15, CAL27, FaDu and Detroit 562
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Immunoblotting to probe for USP9X expression All 4 cell lines express USP9X SCC15FaDu Detroit 562 CAL27 USP9X 290 kDa β tubulin 51 kDa
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Knockdown approach – siRNA
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Immunoblotting to probe for USP9X protein levels 72 h after siRNA treatment USP9X is efficiently knocked down in all four cell lines NT USP9X NT USP9X NT USP9X NT USP9X SCC15 CAL27 FaDu Detroit 562 siRNA USP9X 290 kDa Β tubulin 51 kDa
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Effect on cell aspects – Cell proliferation CyQUANT Assay
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time In absence of USP9X, a decrease in cell numbers was observed CyQUANT Analysis of cell proliferation following siRNA treatment to knockdown USP9X SCC15 Detroit 562 CAL27 FaDu * * * * * * * * * P value < 0.05
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Decrease in cell numbers, – Apoptosis?
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No elevation in apoptosis detected upon depletion of USP9X β tubulin 51 kDa Cleaved PARP-1 89 kDa siRNA NT USP9X NT USP9X NT USP9X NT USP9X NT USP9X NT USP9X time 48h 96h 144h 48h 96h 144h SCC15 CAL27 FaDu Detroit 562 Immunoblotting for cleaved PARP-1
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Decrease in cell numbers in absence of USP9X prompts a role of a
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Decrease in cell numbers in absence of USP9X prompts a role of a “tumor promoter”
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Contradicts predicted oncosupressive role Context specific
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Decrease in cell numbers in absence of USP9X prompts a role of a “tumor promoter” Contradicts predicted oncosupressive role Context specific – Pancreatic cancer
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Decrease in cell numbers in absence of USP9X prompts a role of a “tumor promoter” Contradicts predicted oncosupressive role Context specific – Pancreatic cancer
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Decrease in cell numbers in absence of USP9X prompts a role of a “tumor promoter” Contradicts predicted oncosupressive role Context specific – Pancreatic cancer Tumor suppressor
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Decrease in cell numbers in absence of USP9X prompts a role of a “tumor promoter” Contradicts predicted oncosupressive role Context specific – Pancreatic cancer Tumor suppressor
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Decrease in cell numbers in absence of USP9X prompts a role of a “tumor promoter” Contradicts predicted oncosupressive role Context specific – Pancreatic cancer Tumor suppressor Tumor promotor
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To further confirm, Overexpression of USP9X
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To further confirm, Overexpression of USP9X Usp9x cDNA
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To further confirm, Overexpression of USP9X Usp9x cDNA Linearized the plasmid Lipofectamine 2000 After 3 days: antibiotic selection (12 days) To establish stable cell lines,
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USP9X is ectopically expressed in all four cell lines V5 SCC15CAL27FaDuDetroit 562scc15CAL27FaDuDetroit 562 pDEST51 USP9X pDEST51 β tubulin Immunoblotting to detect ectopic expression of USP9X
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Ectopic USP9X protein expression increased cell proliferation CyQUANT Analysis of cell proliferation following ectopic expression of USP9X SCC15 Detroit 562 CAL27 FaDu * * * * ** * * * * * * * * P value < 0.05
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Cell numbers are directly proportional to level of USP9X protein
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Cell numbers are directly proportional to level of USP9X protein has an oncogenic role
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Molecular mechanism regulated by USP9X
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Murtaza et al, 2015
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Molecular mechanism regulated by USP9X – mTOR – Wnt – Notch Regulates cell proliferation Known USP9X substrates
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Molecular mechanism regulated by USP9X? – mTOR – Wnt – Notch CyclinD1, c-MYC, HES1
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Molecular mechanism regulated by USP9X? – mTOR – Wnt – Notch Quantitate the RNA levels by qPCR CyclinD1, c-MYC, HES1
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RNA extraction cDNA qPCR
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Fold change of target genes 144 h after knockdown of USP9X SCC15 CAL27 FaDuDetroit 562
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Fold change of target genes 144 h after knockdown of USP9X SCC15 CAL27 FaDuDetroit 562
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Fold change of target genes 144 h after knockdown of USP9X SCC15 CAL27 FaDuDetroit 562
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SCC15 CAL27 FaDu Detroit 562 Fold change of target genes 144 h after ectopic expression of USP9X
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Consistently HES1 expression correlated with cell proliferation measured by CyQUANT assay USP9X seems to positively regulate notch pathway
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Consistently HES1 expression correlated with cell proliferation measured by CyQUANT assay USP9X seems to positively regulate notch pathway Hypothesis: USP9X regulates proliferation of head and neck cancer cells through notch pathway
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Conclusions USP9X depletion caused a decrease in cell proliferation Ectopic expression of USP9X led to increase in cell proliferation USP9X positively regulates Notch pathway
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ACKNOWLEDGEMENT Stephen George Nicholas Saunders Wood lab members Funding: Griffith University
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THANK YOU!
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