Siddu et al. report that free amyloid-β peptides promote synapse formation in human neurons, whereas aggregated forms are synaptotoxic. The cover art shows a human induced neuron exposed to a nontoxic concentration of amyloid-β42 (Aβ42) peptide. Under these conditions, neurons exhibit enhanced synaptogenesis, visible as a dense distribution of synaptic puncta along the dendritic arbor. Image credit: Alberto Siddu.
PP2A B55α, a regulatory subunit of protein phosphatase 2 (PP2A), is underexpressed in over 40% of non-small cell lung cancer (NSCLC) cases due to loss of heterozygosity of PPP2R2A, the gene encoding this protein. Given that low PPP2R2A expression correlates with poor prognosis, treating PPP2R2A-deficient NSCLC represents an unmet medical need. Here, we show that PPP2R2A knockdown or its heterozygosity (PPP2R2A+/–) increases cytosolic DNA, leading to cGAS-STING-type I interferon (IFN) pathway activation. PPP2R2A deficiency results in elevated expression of immune checkpoint protein PD-L1 via GSK-3β- and STING-dependent mechanisms. PPP2R2A+/– cancer cells have enhanced sensitivity to PD-L1 blockade in a mouse model of lung cancer due to modulation of the tumor immune microenvironment, resulting in increased NK cells and reduced infiltration and function of regulatory T cells (Tregs). Consequently, PD-L1 antibody treatment increases CD8+ T infiltration and activity, especially in tumors with PPP2R2A heterozygosity. Further, systemic or Treg-specific IFNAR1 blockade reduces the efficacy of PD-L1 blockade in PPP2R2A+/– tumors. Patients with NSCLC with a low PPP2R2A/PD-L1 ratio respond better to immune checkpoint blockade (ICB). These findings underscore the therapeutic potential of ICB in treating PPP2R2A-deficient NSCLC while suggesting that PPP2R2A deficiency could serve as a biomarker for guiding ICB-based therapies.
Zhaojun Qiu, No-Joon Song, Anqi Li, Deepika Singh, Chandra B. Prasad, Chunhong Yan, David P. Carbone, Qi-en Wang, Xiaoli Zhang, Zihai Li, Junran Zhang
Non-small cell lung cancer (NSCLC) exhibits the highest rates of brain metastases (BM) among all solid tumors and presents a significant clinical challenge. The development of novel therapeutic strategies targeting BM is clearly needed. We identified a significant enrichment of MET amplification in lung adenocarcinoma (LUAD) BM compared to primary LUAD and extracranial metastases in oncogene driver-negative patients. Of note, MET amplified BM were responsive to MET inhibitors in vivo including models with acquired MET amplification at the time of metastasis. MET alterations (amplifications and/or mutations) were also more frequently detected in circulating tumor DNA from LUAD BM patients than in those without BM. MET altered BM also demonstrated unique genomic features compared to non-MET altered BM. Transcriptomic analyses revealed that in contrast to MET wildtype BM, MET amplified BM exhibited a more inflamed tumor microenvironment and displayed evidence of metabolic adaptation, particularly a reliance on glycolysis in contrast to oxidative phosphorylation in MET wildtype BM. Further, MET amplified BM demonstrated evidence of epithelial-mesenchymal transition signaling including increased expression of TWIST1. Patients with MET amplified BM had significantly shorter overall survival. These findings highlight MET amplification as a critical driver of LUAD BM, emphasizing its potential as a therapeutic target.
Timothy F. Burns, Sanja Dacic, Anish Chakka, Ethan Miller, Maria A. Velez, Ashwin Somasundaram, Saveri Bhattacharya, Autumn Gaither-Davis, Princey Devadassan, Jingxiao Jin, Vinod Kumar, Arjun Pennathur, Joanne Xiu, Matthew Oberley, Michael J. Glantz, Sonikpreet Aulakh, Uma R. Chandran, Riyue Bao, Curtis Tatsuoka, Laura P. Stabile
Fanconi anemia (FA) confers a high risk (~700-fold increase) of solid tumor formation, most often head and neck squamous cell carcinoma (HNSCC). FA germline DNA repair defects preclude administration of most chemotherapies and prior hematopoietic stem cell transplantation limits use of immunotherapy. Thus, surgery and judicious delivery of radiation offer the only treatment options, with most patients succumbing to their cancers. A paucity of preclinical models has limited the development of new treatments. Here, we report, to our knowledge, the first patient-derived xenografts (PDXs) of FA-HNSCC and highlight the efficacy of FDA-approved EGFR targeted therapies in tumors with high EGFR/p-EGFR levels and the activity of the FDA-approved Bcl-2 inhibitor venetoclax in a FA-HNSCC PDX overexpressing Bcl-2. These findings support the development of precision medicine approaches for FA-HNSCC.
Jennifer Grandis, Hua Li, Benjamin A. Harrison, Andrew L.H. Webster, Joanna Pucilowska, Austin Nguyen, Jinho Lee, Gordon B. Mills, Jovanka Gencel-Augusto, Yan Zeng, Steven R. Long, Mi-Ok Kim, Rex H. Lee, David I. Kutler, Theresa Scognamiglio, Margaret Brandwein-Weber, Mark Urken, Inna Khodos, Elisa de Stanchina, Yu-Chien Lin, Frank X. Donovan, Settara C. Chandrasekharappa, Moonjung Jung, Mathijs A. Sanders, Agata Smogorzewska, Daniel E. Johnson
Mitochondrial fission is mediated by dynamin-related protein 1 (gene name DNM1L) and fusion by mitofusins (MFN1 and MFN2) and optic atrophy 1 (OPA1). The role of mitochondrial dynamics in liver disease and cancer remains poorly understood. We used single, double, and triple liver-specific knockout (KO) mice lacking mitochondrial fission and fusion proteins, along with systematic analyses of mitochondrial morphology, untargeted metabolomics, RNA sequencing, hydrodynamic tail vein injection of oncogenes, and human hepatocellular carcinoma samples. Liver-specific Dnm1l KO (L-Dnm1l) mice showed increased ALT levels and hepatic fibrosis, with spontaneous liver tumors developing by 12 to 18 months of age. L-Mfn1 KO and L-Mfn2 KO mice showed no significant liver damage or tumor development, although a small percentage of double knockout (DKO) mice developed tumors. Triple knockout of Dnm1l, Mfn1, and Mfn2 (TKO) mice experienced significantly reduced liver injury and fibrosis, along with decreased spontaneous and oncogene-induced tumorigenesis. L-Dnm1l KO mice showed increased activation of the cGAS-STING-interferon pathway and pyrimidine metabolism, which were significantly normalized in TKO mice. Deletion of hepatic cGas reduced both basal and oncogene-induced liver injury and tumor development in L-Dnm1l KO mice. These findings indicate that mitochondrial dynamics are crucial for maintaining hepatic pyrimidine metabolism and regulating the cGAS-STING-mediated immune response to prevent liver tumorigenesis.
Xiaowen Ma, Xiaoli Wei, Mengwei Niu, Chen Zhang, Zheyun Peng, Wanqing Liu, Junrong Yan, Xiaoyang Su, Lichun Ma, Shaolei Lu, Wei Cui, Hiromi Sesaki, Wei-Xing Zong, Hong-Min Ni, Wen-Xing Ding
Type 1 Diabetes Mellitus (T1D) is a chronic disease caused by an unremitting autoimmune attack on pancreatic beta cells. This autoimmune chronicity is mediated by stem-like progenitor CD8+ T cells that continually repopulate the pool of beta cell-specific cytolytic effectors. Factors governing the conversion of progenitors to effectors, however, remain unclear. T1D has been linked to a chromosomal region (Xp13-p11) that contains the epigenetic regulator UTX, which suggests a key role for UTX in T1D pathogenesis. Here, we show that T cell-specific UTX deletion in NOD mice protects against T1D development. In T cells of NOD mice and T1D patients, UTX ablation resulted in the accumulation of CD8+ progenitor cells with concomitant deficiency of effectors, suggesting a key role for UTX in poising progenitors for transition to effectors. Mechanistically, UTX’s role in T1D was independent of its inherent histone demethylase activity but instead relied on binding with transcription factors (TCF1 and STAT3) to co-regulate genes important in the maintenance and differentiation of progenitor CD8+ T cells. Together, these findings identify a critical role for UTX in T1D and the UTX:TCF1:STAT3 complex as a therapeutic target for terminating the long-lived autoimmune response.
Ho-Chung Chen, Madison F. Bang, Hsing-Hui Wang, Karl B. Shpargel, Lisa A. Kohn, David Sailer, Shile Zhang, Ethan C. McCarthy, Maryamsadat Seyedsadr, Satchel Stevens, Caitlyn L. H. Pham, Zikang Zhou, Xihui Yin, Nicole M. Wilkinson, Esther M. Peluso, Christian Bustillos, Jessica G. Ortega, Lixin Yang, Ashlyn A. Buzzelli, Reina C. Capati, Dennis J. Chia, Steven D. Mittelman, Christina M. Reh, Jason K. Whitmire, Melissa G. Lechner, Willy Hugo, Maureen A. Su
Therapies targeting the glucagon-like peptide 1 (GLP-1) receptor have revolutionized the treatment of obesity and diabetes. This series of reviews, curated by Dr. Dan Drucker, describes the latest research in this fast-moving in field, from our evolving understanding of the mechanism of GLP-1 receptor signaling to the medicines’ impact on inflammation and the consequences for heart, kidney, and brain health. The reviews also explore the impact of these medicines on conditions beyond their initial indications, including cancer and neurodegenerative disease risk.
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In this episode, Dr. Seth J. Zost presents an antibody lineage from a single donor that binds the active site of influenza neuraminidase, cross-reacts with antigenically diverse viruses, and protects mice from infection...