Skip to Content
Merck
  • FBXO44 promotes DNA replication-coupled repetitive element silencing in cancer cells.

FBXO44 promotes DNA replication-coupled repetitive element silencing in cancer cells.

Cell (2020-12-29)
Jia Z Shen, Zhixin Qiu, Qiulian Wu, Darren Finlay, Guillermina Garcia, Dahui Sun, Juha Rantala, William Barshop, Jennifer L Hope, Ryan C Gimple, Olle Sangfelt, Linda M Bradley, James Wohlschlegel, Jeremy N Rich, Charles Spruck
ABSTRACT

Repetitive elements (REs) compose ∼50% of the human genome and are normally transcriptionally silenced, although the mechanism has remained elusive. Through an RNAi screen, we identified FBXO44 as an essential repressor of REs in cancer cells. FBXO44 bound H3K9me3-modified nucleosomes at the replication fork and recruited SUV39H1, CRL4, and Mi-2/NuRD to transcriptionally silence REs post-DNA replication. FBXO44/SUV39H1 inhibition reactivated REs, leading to DNA replication stress and stimulation of MAVS/STING antiviral pathways and interferon (IFN) signaling in cancer cells to promote decreased tumorigenicity, increased immunogenicity, and enhanced immunotherapy response. FBXO44 expression inversely correlated with replication stress, antiviral pathways, IFN signaling, and cytotoxic T cell infiltration in human cancers, while a FBXO44-immune gene signature correlated with improved immunotherapy response in cancer patients. FBXO44/SUV39H1 were dispensable in normal cells. Collectively, FBXO44/SUV39H1 are crucial repressors of RE transcription, and their inhibition selectively induces DNA replication stress and viral mimicry in cancer cells.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Trichloroacetic acid solution, 6.1 N
Sigma-Aldrich
Monoclonal Anti-α-Tubulin antibody produced in mouse, ascites fluid, clone B-5-1-2
Sigma-Aldrich
Anti-SUV39H1 Antibody, clone MG44, ascites fluid, clone MG44, Upstate®
Sigma-Aldrich
ChIPAb+ Trimethyl-Histone H3 (Lys9) - ChIP Validated Antibody and Primer Set, clone CMA308, from mouse
Sigma-Aldrich
Anti-trimethyl Histone H3 (Lys27) Antibody, from rabbit, purified by affinity chromatography
Sigma-Aldrich
Anti-dimethyl-Histone H3 (Lys79) Antibody, clone NL59, rabbit monoclonal, culture supernatant, clone NL59, Upstate®
Sigma-Aldrich
Ribonuclease A from bovine pancreas, for molecular biology, ≥70 Kunitz units/mg protein, lyophilized
Sigma-Aldrich
Monoclonal Anti-β-Actin antibody produced in mouse, clone AC-15, ascites fluid
Sigma-Aldrich
Monoclonal ANTI-FLAG® M2 antibody produced in mouse, clone M2, purified immunoglobulin (Purified IgG1 subclass), buffered aqueous solution (10 mM sodium phosphate, 150 mM NaCl, pH 7.4, containing 0.02% sodium azide)
Sigma-Aldrich
MISSION® esiRNA, targeting human FBXO44
Sigma-Aldrich
Anti-phospho-Histone H2A.X (Ser139) Antibody, clone JBW301, clone JBW301, from mouse
Sigma-Aldrich
Anti-trimethyl-Histone H3 (Lys36) Antibody, from rabbit, purified by affinity chromatography