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Biology subjects

Wang, B. B.

Publications and source records attributed to Wang, B. B..

4 recordsLinked to original sources

Genetic Ablation and Multi-Omics Profiling Reveal CEP55 as a Key Driver of Tumorigenesis in Diverse Cancer Models

BackgroundCEP55 is a centrosomal protein with emerging oncogenic roles. It is overexpressed in many cancers, where it drives genomic instability, phenocopies PTEN loss and hyperactivates the PI3K/AKT pathway, thereby promoting aggressive and therapy-resistant tumors. MethodsWe developed an inducible Cep55 knockout (KO) mouse model as well as generated primary, immortalized (SV40), and transformed (E1A/Ras) mouse embryonic fibroblasts (MEFs) for functional and proteomic assays. Tumorigenesis was studied using E1A/Ras MEF transplantation and a Pten-deficient genetically engineered mouse model (GEMM). Multi-omics apparatus including proteomics, and spatial transcriptomics, histopathology, immunobloting and functional assays were employed to elucidate underlying mechanisms. Findings were cross-validated using human cancer datasets. ResultsCep55 ablation remodeled the extracellular matrix (ECM), disrupted integrin and oncogenic signaling, reduced AKT/ERK activation, and induced stress pathways. Cep55 knockouts (KO) cells showed impaired proliferation, migration, invasion, and adhesion. In vivo, unlike the embryonic lethality observed in constitutive KOs, the inducible Cep55 deletion was well-tolerated in adult mice. Strikingly, tumors derived from Cep55-null EIA/RAS-transformed MEFs exhibited delayed onset and progression. In the genetically engineered cancer-prone mouse model, Cep55 deletion on a Pten-deficient background led to a greater than seven-fold increase in median survival. Spatial transcriptomics on cancerous tissues revealed that CEP55 regulates ECM remodeling, integrin expression, trafficking, and cell adhesion, supporting its critical role in tumor progression to metastasis. ConclusionCEP55 is dispensable for adult homeostasis but essential for tumorigenesis, especially with PTEN loss. Its deletion suppresses transformation, delays tumor growth, and prolongs survival, supporting CEP55 as a therapeutic target in PTEN-deficient cancers. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/685219v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@3d81e8org.highwire.dtl.DTLVardef@1bd5a7org.highwire.dtl.DTLVardef@167ecf3org.highwire.dtl.DTLVardef@1f57b95_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

Reversible Dissociation of Mitochondrial Complex V Balances Anabolic and Energy-Generating Needs in Cancer

Cancer cell metabolic re-programming provides the excess energy and anabolic precursors necessary to sustain uncontrolled growth. This is partly mediated by the Warburg effect, whereby glucose is converted into ATP and a subset of these anabolic substrates. Concurrently, mitochondrial mass and ATP production decline in most tumors. This raises the question of how increased supplies of glycolysis-derived anabolic substrates can be balanced with those generated by the TCA cycle. Using primary murine liver cancers and cell lines, we show that this can be explained by the dissociation of mitochondrial Complex V (CV or ATP synthase) into its component and functionally-independent Fo and F1 domains. This occurs as a result of marked reductions in MT-ATP6, a CV subunit that stabilizes the Fo-F1 association. Serving as a proton pore, Fo maintains a normal mitochondrial membrane potential without generating ATP, thus allowing the TCA cycle, electron transport chain and anaplerotic reactions to function at high levels. Concurrently, free F1 functions as an ATPase to prevent excessive ATP accumulation. The uncoupling of TCA cycle-derived anabolic substrate production from membrane hyperpolarization and ATP synthesis by a smaller population of more efficient mitochondria allows TCA cycle-generated anabolic precursors to match those generated via glycolysis.

cancer biology↗

Ubr1-induced selective endo-phagy/autophagy protects against the endosomal and Ca2+-induced proteostasis disease stress

The defence mechanisms against endo-lysosomal homeostasis stress remain incompletely understood. Here, we identify Ubr1 as a protein quality control (QC) ubiquitin ligase that counteracts proteostasis stress by enhancing cargo selective autophagy for lysosomal degradation. Astrocyte regulatory cluster membrane protein MLC1 mutations increased intracellular Ca2+ and caused endosomal compartment stress by fusion and enlargement. Endosomal protein QC pathway using ubiquitin QC ligases CHIP and Ubr1 with ESCRT-machinery was able to target only a fraction of MLC1-mutants for lysosomal degradation. As a consequence of the endosomal stress, we found an alternative QC route dependent on Ubr1, SQSTM1/p62 and arginylation to bypass MLC1-mutants to endosomal autophagy (endo-phagy). Significantly, this unfolded a general biological endo-lysosomal QC pathway for arginylated Ubr1-SQSTM1/p62 autophagy targets during Ca2+-assault. Conversely, the loss of Ubr1 with the absence of arginylation elicited endosomal compartment stress. These findings underscore the critical housekeeping role of Ubr1-dependent endo-phagy/autophagy in constitutive and provoked endo-lysosomal proteostasis stress, and link Ubr1 to Ca2+-homeostasis and proteins implicated in various diseases including cancers and brain disorders.

biochemistry↗

Broadly inhibiting anti-neuraminidase monoclonal antibodies induced by trivalent influenza vaccine and H7N9 infection in humans

The majority of antibodies induced by influenza neuraminidase (NA), like those against hemagglutinin (HA), are relatively specific to viruses isolated within a limited time-window as seen in serological studies and the analysis of many murine monoclonal antibodies. We report three broadly reactive human monoclonal antibodies (mAbs) targeting N1 NA. Two were isolated from a young adult vaccinated with trivalent influenza vaccine (TIV), which inhibited N1 NA from viruses isolated from human over a period of a hundred years. The third antibody isolated from a child with acute mild H7N9 infection inhibited both group 1 N1 and group 2 N9 NAs. In addition, the antibodies cross-inhibited the N1 NAs of highly pathogenic avian H5N1 influenza viruses. These antibodies are protective in prophylaxis against seasonal H1N1 viruses in mice. This study demonstrates that human antibodies to N1 NA with exceptional cross-reactivity can be recalled by vaccination and highlights the importance of standardizing the NA antigen in seasonal vaccines to offer optimal protection.\n\nImportanceAntibodies to the influenza NA can provide protection against influenza disease. Analysis of human antibodies to NA lags behind that for HA. We show that human monoclonal antibodies against NA induced by vaccination and infection can be very broadly reactive and able to inhibit a wide spectrum of N1 NAs between 1918 and 2018. This suggests that antibodies to NA may be a useful therapy, and that efficacy of influenza vaccines could be enhanced by ensuring appropriate content of NA antigen.\n\nHighlights of the paperO_LIAntibodies that inhibit influenza viruses with N1 neuraminidase (NA), with broad reactivity for viruses isolated between 1918-2018, can be isolated from human recipients of seasonal influenza vaccine\nC_LIO_LIAntibodies targeting N1 NA of human seasonal H1N1 viruses can cross-react with a variety of avian N1 neuraminidases\nC_LIO_LIAcute H7N9 infection can recall memory B cells to N1 NA and elicit cross-reactive antibodies to the group 1 N1 and group 2 N9 NAs\nC_LIO_LIAntibodies to N1 NA with this broad reactivity protect against lethal virus challenge\nC_LI

immunology↗