14 th International VHL Medical/Research Symposium New VHL Regulatory Pathways and Therapeutic Implications in ccRCC Qing Zhang, Ph.D Associate Professor, Dept. Pathology UT Southwestern Medical Center 10/29/2020
Somatic Mutation of clear cell Renal Cell Carcinoma (ccRCC) (Sato Y. et al., Nat Genet, 2013)
Target Therapies in Kidney Cancer Toni Choueiri William Kaelin Choueiri TK and Kaelin WG., Nature Medicine, 2020
Targeting VEGFR/PDGFR in Kidney Cancer
W. Marston Linehan (NCI) Berton Zbar (NCI) “...we are ignoring other aspects of ccRCC that may need to be targeted to achieve maximal therapeutic efficacy....” Linehan WM et al., Nature Reviews Clinical Oncology 10, 614–615, (2013) Can we identify additional therapeutic avenues in ccRCC regulated by VHL? How?
VHL and P- OH HIF1α -564 Binding Hydroxylation of HIF1 α on proline residue 564 (p-OH HIF) primes its binding with VHL ubiquitin E3 ligase complex (including pVHL, Elogin B and C, VBC) Based on the work from Kaelin, Ratcliffe and Pavletich
A Genome-Wide In Vitro Expression Cloning Strategy ~17,000 cDNA ORF bacterial stock 24 unique cDNA/pool, 700 pools William Kaelin, DFCI 96 well plate, 8 plates Mini-Preps Marc Kirschner, HMS 35 S Methionine In Vitro Translated Proteins
Screening Strategy for Potential VHL Substrates 35 S Labeled Proteins 700 pools (24 genes/pool) GST-VHL complex x WT HIF P-OH HIF Peptide Peptide x Run SDS-PAGE & autoradiography GST-VHL complex IVT WT P-OH De-convolution Individual binding assay ZHX2 Identification of novel VHL substrates SFMBT1
Zinc fingers and homoboxes protein 2 (ZHX2) Zhang J et al., Science , 2018, PMID 30026228
Scm-Like With Four Malignant Brain Tumor Domains Protein 1 (SFMBT1) Nady N et al., Journal of Molecular Biology, 2012
VHL Regulates SFMBT1 Protein Levels Mol Cell , Feb 4 th , 2020 Xijuan Liu, Ph.D 11/2/2020 13
SFMBT1 Depletion Leads to Decreased ccRCC Cell Growth 14 11/2/2020
SFMBT1 Depletion Leads to Decreased ccRCC Tumor Growth 11/2/2020 15
VHL mutant ccRCC Tumors Displays Upregulated SFMBT1 Protein Levels Missense VHL mutant
Integrated Analyses for SFMBT1 Regulated Events in ccRCC Jeremy Simon SPHK1 Chris Fan
SPHK1 is an SFMBT1 Direct Target Gene in ccRCC
SPHK1 is a Key SFMBT1 Downstream Target Gene in ccRCC 11/2/2020 19
SPHK1 Inhibitor Represses ccRCC Cell Proliferation PF-543: SPHK1 inhibitor 20 11/2/2020
SPHK1 Inhibitor Represses ccRCC Tumorigenesis
Summary 1: VHL-SFMBT1-SPHK1 Signaling Drives Oncogenesis in ccRCC Mol Cell, 2020, PMID 32023483
How to Target ccRCC that are Mostly VHL Null 1. Target VHL regulated pathways, such as HIF2α, ZHX2 and SFMBT1 Challenge: It is difficult to target transcriptional factors Not all of ccRCC cell lines respond to HIF2α inhibitors (~50%) 2. Target synthetic lethality pathways for VHL loss
Synthetic Lethality Targeting in Cancer VHL TBK1 Brunen D and Bernards R., Nature Reviews Clinical Oncology 2017
TBK1 in Innate Immunity Liu s et al., Science, 2015
TBK1 May be a Synthetic Lethality Partner for VHL Loss in ccRCC Cancer Discovery , 2020, PMID: 31810986 Lianxin Hu, Ph.D
VHL Loss/Hypoxia Activates TBK1 Oncogenic Signaling in ccRCC A VHL EglN1 PPM1B OH VHL WT TBK1 TBK1 TBK1 OH or Normoxia TBK1 P P P P B PPM1B VHL EglN1 OH VHL Loss TBK1 TBK1 P P ℗ - p62 TBK1 P Tumorigenesis EglN1 Hypoxia OH TBK1 TBK1 P P Cancer Discovery , 2020, PMID: 31810986
ccRCC Tumors Display Higher TBK1 Activity Compared to Paired Normals Normal Tumor Normal Tumor P=0.0016 P=0.0062 TBK1 P=0.0062 pTBK1 Patient #1 Patient #2 TMA1 TMA2 Collaboration with Kan Gong, Peking University 11/2/2020 28
TBK1 Depletion Leads to Decreased ccRCC Tumor Growth and Metastasis
TBK1 Inhibitor Selectively Suppresses VHL Null Cancer Cells EV UMRC6 VHL 1.5 Ev VHL Fold change ** 1.0 0.5 0.0 Jenkins, R. W. et al., Cancer Discov 8 (2018). DMSO CMPD1
TBK1 PROTACs Selectively Suppresses VHL Null ccRCC Cell Growth Cereblon Frances Potjewyd, Ph.D DMSO UNC6587 UNC6587 DMSO Ev 2.0 VHL ** Fold change 1.5 EV UMRC6 1.0 0.5 VHL Lindsey James, Ph.D 0.0 DMSO UNC6587
Summary II and Overall Future Directions 1. VHL Null cells are sensitive to TBK1 depletion/inhibition 2. VHL loss leads to hyper-activation of TBK1 3. ccRCC patients display increased TBK1 phosphorylation 4. TBK1 is essential for ccRCC tumorigenesis by phosphorylating p62 on Ser366 Future Directions Study SFMBT1 signaling axis and its therapeutic implication in ccRCC Study the role of TBK1 on tumor and tumor microenvironment in ccRCC Potential combination therapies in kidney cancer
Acknowledgement Lab Members UNC-Chapel Hill R01 CA211732 Jing Zhang (former) Al Baldwin Lianxin Hu Cheng Fan Giada Zurlo Chuck M. Perou Chengheng Liao Jeremy Simon Xijuan Liu (UNC) William Kim Kai Hong (former) Xian Chen Jin Zhou Lindsey James Haibiao Xie Frances Potjewyd Weilong Chen Hongwei Yao University of Edinburgh Alex Von Kriegsheim Harvard Medical School Peking University William Kaelin Marc Kirschner Kan Gong UTSW James Brugarolas Weibo Luo Payal Kapur Rolf Brekken
Recommend
More recommend
