Whether transcriptional regulators are functionally involved in mitosis is a fundamental question in cell biology. Here we report that the RNF20/40 complex, a major ubiquitin ligase catalysing histone H2B monoubiquitination, interacts with the motor protein Eg5 during mitosis and participates in spindle assembly. We show that the RNF20/40 complex monoubiquitinates and stabilizes Eg5. Loss of RNF20/40 results in spindle assembly defects, cell cycle arrest and apoptosis. Consistently, depletion of either RNF20/40 or Eg5 suppresses breast cancer in vivo. Significantly, RNF20/40 and Eg5 are concurrently upregulated in human breast carcinomas and high Eg5 expression is associated with poorer overall survival of patients with luminal A, or B, breast cancer. Our study uncovers an important spindle assembly role of the RNF20/40 complex, and implicates the RNF20/40-Eg5 axis in breast carcinogenesis, supporting the pursuit of these proteins as potential targets for breast cancer therapeutic interventions.

The disruption of epigenetic regulation is common in tumors; the abnormal expression of epigenetic factors leads to cancer occurrence and development. In this study, to investigate the potential function of histone methylation regulators in lung adenocarcinoma (LUAD), we performed differential expression analysis using RNA-seq data downloaded from The Cancer Genome Atlas (TCGA) database, and identified CBX2 and EZH2 as obviously upregulated histone methylation regulators. CBX2 knockdown significantly inhibited LUAD cell growth and metastasis in vitro and in vivo. The combined high expression of CBX2 and EZH2 was an indicator of poor prognosis in LUAD. The inhibition of both CBX2 and EZH2 exerted cooperative suppressive effects on the growth and metastasis of LUAD cells. Mechanistically, we revealed that CBX2 and EZH2 downregulated several PPAR signaling pathway genes and tumor suppressor genes through binding to their promoter cooperatively or separately. Furthermore, knockdown of CBX2 improved the therapeutic efficiency of EZH2 inhibitor on A549 cells. Our study reveals the cooperative oncogenic role of CBX2 and EZH2 in promoting LUAD progression, thereby providing potential targets for LUAD diagnosis and therapy.

Oligonucleotide-based medicine faces challenges in efficiently crossing the blood-brain barrier and rapidly reducing toxic proteins. To address these challenges, here we establish an integrated modality, brain-penetrant DNA nanoflowers incorporated with oligonucleotide-based proteolysis targeting chimeras. Using FUS as a proof-of-concept, mutations of which cause frontotemporal dementia and amyotrophic lateral sclerosis, we demonstrate that a FUS-engaging RNA oligonucleotide crosslinked to a ligand for Cereblon efficiently degrade FUS and its cytoplasmic disease-causing mutants through a ubiquitin-proteasomal pathway. The DNA nanoflower contains hundreds of oligonucleotide binding sites and transferrin receptor-engaging aptamers, allowing efficient loading of the oligonucleotide-based degrader and engaging transferrin receptors for brain delivery. A single dose intravenous injection of this modality reaches brain parenchyma within 2 h and degrades 80% FUS protein there, sustained for two weeks without noticeable toxicity. DNA nanoflower oligonucleotide-based degrader is a therapeutic strategy for neurodegenerative diseases that leverages the advantages of designer oligonucleotides and targeted protein degradation.

DOT1L promotes angiogenesis through cooperative regulation of VEGFR2 with ETS-1 DOT1L promotes angiogenesis through cooperative regulation of VEGFR2 with ETS-1

The initiation and transduction of DNA damage response (DDR) occur in the context of chromatin, and modifications as well as the structure of chromatin are crucial for DDR signaling. How the profound chromatin alterations are confined to DNA lesions by epigenetic factors remains largely unclear. Here, we discover that JMJD6, a Jumonji C domain-containing protein, is recruited to DNA double-strand breaks (DSBs) after microirradiation. JMJD6 controls the spreading of histone ubiquitination, as well as the subsequent accumulation of repair proteins and transcriptional silencing around DSBs, but does not regulate the initial DNA damage sensing. Furthermore, JMJD6 deficiency results in promotion of the efficiency of nonhomologous end joining (NHEJ) and homologous recombination (HR), rapid cell-cycle checkpoint recovery, and enhanced survival after irradiation. Regarding the mechanism involved, we demonstrate that JMJD6, independently of its catalytic activity, interacts with SIRT1 and recruits it to chromatin to downregulate H4K16ac around DSBs. Our study reveals JMJD6 as a modulator of the epigenome around DNA lesions, and adds to the understanding of the role of epigenetic factors in DNA damage response.