Cell biology
Abstract
TMPRSS2:ERG gene fusion (T:E fusion) in prostate adenocarcinoma (PCa) puts ERG under androgen receptor (AR) regulated TMPRSS2 expression. T:E fusion is associated with PTEN loss, and is highly associated with decreased INPP4B expression, which together may compensate for ERG-mediated suppression of AKT signaling. We confirmed in PCa cells and a mouse PCa model that ERG suppresses IRS2 and AKT activation. In contrast, ERG downregulation did not increase INPP4B, suggesting its decrease is indirect and reflects selective pressure to suppress INPP4B function. Notably, INPP4B expression is decreased in PTEN-intact and PTEN-deficient T:E fusion tumors, suggesting selection for a nonredundant function. As ERG in T:E fusion tumors is AR regulated, we further assessed whether AR inhibition increases AKT activity in T:E fusion tumors. A T:E fusion positive PDX had increased AKT activity in vivo and response to AKT inhibition in vitro after androgen deprivation. Moreover, two clinical trials of neoadjuvant AR inhibition prior to radical prostatectomy showed greater increases in AKT activation in the T:E fusion positive versus negative tumors. These findings indicate that AKT activation may mitigate the efficacy of AR targeted therapy in T:E fusion PCa, and that these patients may most benefit from combination therapy targeting AR and AKT.
Authors
Fen Ma, Sen Chen, Luigi Cecchi, Betul Ersoy-Fazlioglu, Joshua W. Russo, Seiji Arai, Seifeldin Awad, Carla Calagua, Fang Xie, Larysa Poluben, Olga Voznesensky, Anson T. Ku, Fatima Karzai, Changmeng Cai, David J. Einstein, Huihui Ye, Xin Yuan, Alex Toker, Mary-Ellen Taplin, Adam G. Sowalsky, Steven P. Balk
Abstract
Type 1 diabetes (T1D) is characterized by the autoimmune destruction of most insulin-producing β-cells, along with dysregulated glucagon secretion from pancreatic α-cells. We conducted an integrated analysis that combines electrophysiological and transcriptomic profiling, along with machine learning, of islet cells from T1D donors. The few surviving β-cells exhibit altered electrophysiological properties and transcriptomic signatures indicative of increased antigen presentation, metabolic reprogramming, and impaired protein translation. In α-cells, we observed hyper-responsiveness and increased exocytosis, which are associated with upregulated immune signaling, disrupted transcription factor localization and lysosome homeostasis, as well as dysregulation of mTORC1 complex signaling. Notably, key genetic risk signals for T1D were enriched in transcripts related to α-cell dysfunction, including MHC class I, which were closely linked with α-cell dysfunction. Our data provide what we believe are novel insights into the molecular underpinnings of islet cell dysfunction in T1D, highlighting pathways that may be leveraged to preserve residual β-cell function and modulate α-cell activity. These findings underscore the complex interplay between immune signaling, metabolic stress, and cellular identity in shaping islet cell phenotypes in T1D.
Authors
Theodore dos Santos, Xiao-Qing Dai, Robert C. Jones, Aliya F. Spigelman, Hannah M. Mummey, Jessica D. Ewald, Cara E. Ellis, James G. Lyon, Nancy Smith, Austin Bautista, Jocelyn E. Manning Fox, Norma F. Neff, Angela M. Detweiler, Michelle Tan, Rafael Arrojo e Drigo, Jianguo Xia, Joan Camunas-Soler, Kyle J. Gaulton, Stephen R. Quake, Patrick E. MacDonald
Abstract
Whether amyloid-β (Aβ) peptides are synaptogenic or synaptotoxic remains a pivotal open question in Alzheimer’s disease research. Here, we chronically treated human neurons with precisely controlled concentrations of chemically defined synthetic Aβ40, Aβ42, and Aβ42arctic peptides that exhibit distinct aggregation propensities. Remarkably, chronic exposure of human neurons to free Aβ40 at higher concentrations or to free Aβ42 at lower concentrations potently promoted synapse formation. In contrast, aggregated Aβ42 or Aβ42arctic at higher concentrations were neurotoxic and synaptotoxic. The synaptotoxic effects of Aβ peptides manifested as an initial contraction of the synaptic vesicle cluster followed by synapse loss. Aβ40 and Aβ42 peptides with scrambled or inverted sequences were inactive. Thus, our experiments reveal that Aβ peptides exhibit an aggregation-dependent functional dichotomy that renders them either synaptogenic or synaptotoxic, thereby providing insight into how Aβ peptides straddle a thin line between physiological synapse organization and pathological synapse disruption. Among others, our data suggest that Alzheimer’s disease therapies might aim to shift the balance of Aβ peptides from the aggregated to the free state instead of suppressing all Aβ peptides.
Authors
Alberto Siddu, Silvia Natale, Connie H. Wong, Hamidreza Shaye, Thomas C. Südhof
Abstract
Activating mutations in PIK3CA, the gene encoding the catalytic p110-alpha subunit of PI3K, are some of the most frequent genomic alterations in breast cancer. Alpelisib, a small-molecule inhibitor that targets p110-alpha, is a recommended drug for patients with PIK3CA-mutant advanced breast cancer. However, clinical success for PI3K inhibitors has been limited by their narrow therapeutic window. The lipid phosphatase PTEN is a potent tumour suppressor and a major negative regulator of the PI3K pathway. Unsurprisingly, inactivating mutations in PTEN correlate with tumour progression and resistance to PI3K inhibition due to persistent PI3K signalling. Here we demonstrate that PI3K inhibition leads rapidly to the inactivation of PTEN. Using a functional genetic screen we show that this effect is mediated by a USP10-GSK3-B signalling axis, in which USP10 stabilizes GSK3-B resulting in GSK3-B-mediated phosphorylation of the C-terminal tail of PTEN. This phosphorylation inhibits PTEN dimerization and thus prevents its activation. Downregulation of GSK3-B or USP10 re-sensitizes PI3K inhibitor resistant breast cancer models and patient derived organoids to PI3K inhibition and induces tumour regression. Our study establishes that enhancing PTEN activity is a new strategy to treat PIK3CA mutant tumours and provides a strong rationale for pursuing USP10 inhibitors in the clinic.
Authors
Nishi Kumari, Sarah CE. Wright, Christopher M. Witham, Laia Monserrat, Marta Palafox, John Lalith Charles Richard, Carlotta Costa, Moshe Elkabets, Mark Agostino, Theresa Klemm, Melissa K. Eccles, Alexandra Garnham, Ting Wu, Jonas A. Nilsson, Nikita Walz, Veena Venugopal, Anthony Cerra, Natali Vasilevski, Stephanie C. Bridgeman, Sona Bassi, Azad Saei, Moutaz Helal, Philipp Neundorf, Angela Riedel, Mathias Rosenfeldt, Jespal Gill, Nikolett Pahor, Oliver Hartmann, Jacky Chung, Sachdev S. Sidhu, Nina Moderau, Sudhakar Jha, Jordi Rodon, Markus E. Diefenbacher, David Komander, Violeta Serra, Pieter Eichhorn
Abstract
3-O-sulfation of heparan sulfate (HS) is the key determinant for binding and activation of Antithrombin III (AT). This interaction is the basis of heparin treatment to prevent thrombotic events and excess coagulation. Antithrombin-binding HS (HSAT) is expressed in human tissues, but is thought to be expressed in the subendothelial space, mast cells, and follicular fluid. Here we show that HSAT is ubiquitously expressed in the basement membranes of epithelial cells in multiple tissues. In the pancreas, HSAT is expressed by healthy ductal cells and its expression is increased in premalignant pancreatic intraepithelial neoplasia lesions (PanINs), but not in pancreatic ductal adenocarcinoma (PDAC). Inactivation of HS3ST1, a key enzyme in HSAT synthesis, in PDAC cells eliminated HSAT expression, induced an inflammatory phenotype, suppressed markers of apoptosis, and increased metastasis in an experimental mouse PDAC model. HSAT-positive PDAC cells bind AT, which inhibits the generation of active thrombin by tissue factor (TF) and Factor VIIa. Furthermore, plasma from PDAC patients showed accumulation of HSAT suggesting its potential as a marker of tumor formation. These findings suggest that HSAT exerts a tumor suppressing function through recruitment of AT and that the decrease in HSAT during progression of pancreatic tumorigenesis increases inflammation and metastatic potential.
Authors
Thomas Mandel Clausen, Ryan J. Weiss, Jacob R. Tremblay, Benjamin P. Kellman, Joanna Coker, Leo A. Dworkin, Jessica P. Rodriguez, Ivy M. Chang, Timothy Chen, Vikram Padala, Richard Karlsson, Hyemin Song, Kristina L. Peck, Satoshi Ogawa, Daniel R. Sandoval, Hiren J. Joshi, Gaowei Wang, L. Paige Ferguson, Nikita Bhalerao, Allison Moores, Tannishtha Reya, Maike Sander, Thomas C. Caffrey, Jean L. Grem, Alexandra Aicher, Christopher Heeschen, Dzung Le, Nathan E. Lewis, Michael A. Hollingsworth, Paul M. Grandgenett, Susan L. Bellis, Rebecca L. Miller, Mark M. Fuster, David W. Dawson, Dannielle D. Engle, Jeffrey D. Esko
Abstract
A cornerstone of research to improve cancer outcomes involves studies of model systems to identify causal drivers of oncogenesis, understand mechanisms leading to metastases, and develop new therapeutics. While most cancer types are represented by large cell line panels that reflect diverse neoplastic genotypes and phenotypes found in patients, prostate cancer is notable for a very limited repertoire of models that recapitulate the pathobiology of human disease. Of these, Lymph node carcinoma of the prostate (LNCaP) has served as the major resource for basic and translational studies. Here, we delineated the molecular composition of LNCaP and multiple substrains through analyses of whole genome sequences, transcriptomes, chromatin structure, AR cistromes, and functional studies. Our results determined that LNCaP exhibits substantial subclonal diversity, ongoing genomic instability and phenotype plasticity. While several oncogenic features were consistently present across strains, others were unexpectedly variable such as ETV1 expression, Y chromosome loss, a reliance on WNT and glucocorticoid receptor activity, and distinct AR alterations maintaining AR pathway activation. These results document the inherent molecular heterogeneity and ongoing genomic instability that drive diverse prostate cancer phenotypes and provide a foundation for the accurate interpretation and reproduction of research findings.
Authors
Arnab Bose, Armand Bankhead III, Ilsa Coleman, Thomas Persse, Wanting Han, Patricia Galipeau, Brian Hanratty, Tony Chu, Jared Lucas, Dapei Li, Rabeya Bilkis, Pushpa Itagi, Sajida Hassan, Mallory Beightol, Minjeong Ko, Ruth Dumpit, Michael Haffner, Colin Pritchard, Gavin Ha, Peter S. Nelson
Abstract
Pancreatic cancer (PC) is notoriously resistant to both chemotherapy and immunotherapy, presenting a major therapeutic challenge. Epigenetic modifications play a critical role in PC progression, yet their contribution to chemoimmunotherapy resistance remains poorly understood. Here, we identified the transcription factor ZEB1 as a critical driver of chemoimmunotherapy resistance in PC. ZEB1 knockdown synergized with gemcitabine and anti-PD1 therapy, markedly suppressed PC growth, and prolonged survival in vivo. Single-cell and spatial transcriptomics revealed that ZEB1 ablation promoted tumor pyroptosis by recruiting and activating GZMA+CD8+ T cells in the tumor core through epigenetic upregulation of CXCL16. Meanwhile, ZEB1 blockade attenuates CD44+ neutrophil-induced CD8+ T cell exhaustion by reducing tumor-derived SPP1 secretion, which otherwise promotes exhaustion through activation of the PD-L1–PD-1 pathway. Clinically, high ZEB1 expression correlated with chemoresistance, immunosuppression, and diminished CXCL16 levels in PC patients. Importantly, the epigenetic inhibitor Mocetinostat (targeting ZEB1) potentiated chemoimmunotherapy efficacy, including anti-PD1 and CAR-T therapies, in patient-derived organoids, xenografts, and orthotopic models. Our study unveils ZEB1 as a master epigenetic regulator of chemoimmunotherapy resistance and proposes its targeting as a transformative strategy for PC treatment.
Authors
Shaobo Zhang, Yumeng Hu, Zhijun Zhou, Gaoyuan Lv, Chenze Zhang, Yuanyuan Guo, Fangxia Wang, Yuxin Ye, Haoran Qi, Hui Zhang, Wenming Wu, Min Li, Mingyang Liu
Abstract
Few drugs are available for rare diseases due to economic disincentives. However, tailored medications for extremely-rare disorders (N-of-1) offer a ray of hope. Artificial antisense oligonucleotides (ASOs) are now best known for their use in spinal muscular atrophy (SMA). The success of nusinersen/Spinraza for SMA indicates ASO-therapies' potential for other rare conditions. We propose a strategy to develop N-of-1 ASOs for treating one form of trichothiodystrophy (TTD), a rare condition with multisystem abnormalities and reduced life expectancy, associated with instability and greatly reduced amounts of the DNA-repair/transcription factor TFIIH. The therapeutic target carry mutations in GTF2H5, encoding the TFIIH-p8 subunit. This approach was inspired by the diagnosis and molecular dissection of a xeroderma pigmentosum (XP) case with mutations in GTF2H4, encoding the TFIIH-p52 subunit. This is newly classified as a ninth XP complementation-group, XP-J, identified five decades after the discovery of the other XP complementation-groups. The p8-p52 interaction is required to support the TFIIH-complex formation, and the patient's p52 C-terminal truncation results in the complete absence of p8 in TFIIH. However, intriguingly, TFIIH remained stable in vivo, and the XP-J patient did not exhibit any TTD-features. The aim of our ASO-design is to induce a C-terminal truncation of p52 and we have successfully stabilised TFIIH in p8-deficient TTD-A patient cells.
Authors
Yuka Nakazawa, Lin Ye, Yasuyoshi Oka, Hironobu Morinaga, Kana Kato, Mayuko Shimada, Kotaro Tsukada, Koyo Tsujikawa, Yosuke Nishio, Hiva Fassihi, Shehla Mohammed, Alan R. Lehmann, Tomoo Ogi
Abstract
Understanding the genetic causes of diseases affecting pancreatic β cells and neurons can give insights into pathways essential for both cell types. Microcephaly, epilepsy and diabetes syndrome (MEDS) is a congenital disorder with two known aetiological genes, IER3IP1 and YIPF5. Both genes encode proteins involved in endoplasmic reticulum (ER) to Golgi trafficking. We used genome sequencing to identify 6 individuals with MEDS caused by biallelic variants in the novel disease gene, TMEM167A. All had neonatal diabetes (diagnosed <6 months) and severe microcephaly, five also had epilepsy. TMEM167A is highly expressed in developing and adult human pancreas and brain. To gain insights into the mechanisms leading to diabetes, we silenced TMEM167A in EndoC-βH1 cells and knocked-in one patient’s variant, p.Val59Glu, in induced pluripotent stem cells (iPSCs). Both TMEM167A depletion in EndoC-βH1 cells and the p.Val59Glu variant in iPSC-derived β cells sensitized β cells to ER stress. The p.Val59Glu variant impaired proinsulin trafficking to the Golgi and induced iPSC-β cell dysfunction. The discovery of TMEM167A variants as a new genetic cause of MEDS highlights a critical role of TMEM167A in the ER to Golgi pathway in β cells and neurons.
Authors
Enrico Virgilio, Sylvia Tielens, Georgia Bonfield, Fang-Shin Nian, Toshiaki Sawatani, Chiara Vinci, Molly Govier, Hossam Montaser, Romane Lartigue, Anoop Arunagiri, Alexandrine Liboz, Flavia Natividade da Silva, Maria Lytrivi, Theodora Papadopoulou, Matthew N. Wakeling, James Russ-Silsby, Pamela Bowman, Matthew B. Johnson, Thomas W. Laver, Anthony Piron, Xiaoyan Yi, Federica Fantuzzi, Sirine Hendrickx, Mariana Igoillo-Esteve, Bruno J. Santacreu, Jananie Suntharesan, Radha Ghildiyal, Darshan G. Hegde, Nikhil Avnish Shah, Sezer Acar, Beyhan Özkaya Dönmez, Behzat Özkan, Fauzia Mohsin, Iman M. Talaat, Mohamed Tarek Abbas, Omar Saied Abbas, Hamed Ali Alghamdi, Nurgun Kandemir, Sarah E. Flanagan, Raphael Scharfmann, Peter Arvan, Matthieu Raoux, Laurent Nguyen, Andrew T. Hattersley, Miriam Cnop, Elisa De Franco
Abstract
B-lymphocytes play major adaptive immune roles, producing antibody and driving T-cell responses. However, how immunometabolism networks support B-cell activation and differentiation in response to distinct receptor stimuli remains incompletely understood. To gain insights, we systematically investigated acute primary human B-cell transcriptional, translational and metabolomic responses to B-cell receptor (BCR), Toll-like receptor 9 (TLR9), CD40-ligand (CD40L), interleukin-4 (IL4) or combinations thereof. T-independent BCR/TLR9 co-stimulation, which drives malignant and autoimmune B-cell states highly induced the transaminase branched chain amino acid transaminase 1 (BCAT1), which localized to lysosomal membranes to support branched chain amino acid synthesis and mechanistic target of rapamycin complex 1 (mTORC1) activation. BCAT1 inhibition blunted BCR/TLR9, but not CD40L/IL4-triggered B-cell proliferation, IL10 expression and BCR/TLR pathway-driven lymphoma xenograft outgrowth. These results provide a valuable resource, reveal receptor-mediated immunometabolism remodeling to support key B-cell phenotypes and identify BCAT1 as an activated B-cell therapeutic target.
Authors
Rui Guo, Yizhe Sun, Matthew Y. Lim, Hardik Shah, Joao A. Paulo, Rahaman A. Ahmed, Weixing Li, Yuchen Zhang, Haopeng Yang, Liang Wei Wang, Daniel Strebinger, Nicholas A. Smith, Meng Li, Merrin Man Long Leong, Michael Lutchenkov, Jin-Hua Liang, Zhixuan Li, Yin Wang, Rishi Puri, Ari Melnick, Michael R. Green, John M. Asara, Adonia E. Papathanassiu, Duane R. Wesemann, Steven P. Gygi, Vamsi K. Mootha, Benjamin E. Gewurz
No posts were found with this tag.
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)