Issue published February 15, 2022 Previous issue | Next issue
On the cover: Mechanisms of resistance to KRAS G12C inhibitors
Tsai et al. report on a rapid-autopsy case of a patient with lung adenocarcinoma whose tumors initially responded to sotorasib, the first approved KRAS G12C inhibitor, but quickly became resistant. As depicted in the cover image, pretreatment (yellow) and posttreatment (red) tumors were collected and analyzed by deep-RNA and whole-exome sequencing. Integrated bioinformatic approaches revealed many diverse cell-autonomous and tumor microenvironment remodeling mechanisms of acquired drug resistance. Image credit: Jordan Pietz.
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Reviews
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Abstract
Deregulated Wnt/β-catenin signaling is one of the main genetic alterations in human hepatocellular carcinoma (HCC). Comprehensive genomic analyses have revealed that gain-of-function mutation of CTNNB1, which encodes β-catenin, and loss-of-function mutation of AXIN1 occur in approximately 35% of human HCC samples. Human HCCs with activation of the Wnt/β-catenin pathway demonstrate unique gene expression patterns and pathological features. Activated Wnt/β-catenin synergizes with multiple signaling cascades to drive HCC formation, and it functions through its downstream effectors. Therefore, strategies targeting Wnt/β-catenin have been pursued as possible therapeutics against HCC. Here, we review the genetic alterations and oncogenic roles of aberrant Wnt/β-catenin signaling during hepatocarcinogenesis. In addition, we discuss the implication of this pathway in HCC diagnosis, classification, and personalized treatment.
Authors
Chuanrui Xu, Zhong Xu, Yi Zhang, Matthias Evert, Diego F. Calvisi, Xin Chen
×Abstract
The importance of the microbiota in the development of colorectal cancer (CRC) is increasingly evident, but identifying specific microbial features that influence CRC initiation and progression remains a central task for investigators. Studies determining the microbial mechanisms that directly contribute to CRC development or progression are revealing bacterial factors such as toxins that contribute to colorectal carcinogenesis. However, even when investigators have identified bacteria that express toxins, questions remain about the host determinants of a toxin’s cancer-potentiating effects. For other cancer-correlating bacteria that lack toxins, the challenge is to define cancer-relevant virulence factors. Herein, we evaluate three CRC-correlating bacteria, colibactin-producing Escherichia coli, enterotoxigenic Bacteroides fragilis, and Fusobacterium nucleatum, for their virulence features relevant to CRC. We also consider the beneficial bioactivity of gut microbes by highlighting a microbial metabolite that may enhance CRC antitumor immunity. In doing so, we aim to elucidate unique and shared mechanisms underlying the microbiota’s contributions to CRC and to accelerate investigation from target validation to CRC therapeutic discovery.
Authors
Slater L. Clay, Diogo Fonseca-Pereira, Wendy S. Garrett
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Commentaries
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Abstract
Kidney function decreases with age and may soon limit millions of lives as the proportion of the population over 70 years of age increases. Glycogen synthase kinase 3β (GSK3β) is involved with metabolism and may have a role in kidney senescence, positioning it as a target for complications from chronic kidney disease. However, different studies suggest GSK3 has contrasting effects. In this issue of the JCI, Fang et al. explored the function of GSK3β and the interplay with lithium using human tissue and mouse models. Notably, GSK3β was overexpressed and activated in aging mice, and depleting GSK3β reduced senescence and glomerular aging. In this Commentary, we explore the similarities and differences between Fang et al. and previous findings by Hurcombe et al. These findings should prompt further study of lithium and other GSK3β inhibitors as a means of extending glomerular function in individuals with chronic kidney disease.
Authors
Jordan A. Kreidberg, Valerie A. Schumacher
×Abstract
KRAS G12C inhibitors such as sotorasib and adagrasib are often effective in KRAS G12C–driven non–small cell lung cancer (NSCLC) patients. However, acquired resistance limits long-term patient survival. In this issue of the JCI, Tsai et al. present a comprehensive genetic analysis of multiple tumors with acquired sotorasib resistance obtained through an autopsy of a patient with KRAS G12C–mutant NSCLC. This analysis of pre- and posttreatment tumors uncovered cancer cell–intrinsic and –extrinsic features of resistance, including reactivation of KRAS-mediated signaling, reprogramming of metabolism, epithelial-mesenchymal transition, and tumor microenvironment changes. This elegant study demonstrates the multifaceted nature of KRAS G12C inhibitor clinical resistance and potential avenues to overcome resistance.
Authors
Tadashi Manabe, Trever G. Bivona
×Abstract
A challenge in cancer treatment is targeting cancer cells while sparing normal cells. Thus, identifying cancer-specific neoepitopes is an active research area. Neoepitopes are generated by the accumulation of mutations; however, deadly cancer types, including pancreatic cancer, have a low mutational burden and, consequently, a paucity of neoantigens. In this issue of the JCI, Lim, Zhou, and colleagues describe a neoepitope generated upon proteolytic cleavage of the transmembrane CUB domain containing protein 1 (CDCP1). CDCP1 is overexpressed in cancer and portends a worse prognosis; previous attempts to target CDCP1 reduced cancer growth, but adversely affected the host. Here, the authors generated an antibody that specifically targeted cleaved CDCP1 (c-CDCP1) and developed a drug conjugate, a vector for radioactive ions, and a mediator of T cell activation. The therapeutics inhibited pancreatic cancer cell growth in vitro and in vivo. Exploiting proteolytic cleavage-derived neoantigens opens an attractive way for specifically targeting cancer cells.
Authors
Katelyn L. Donahue, Marina Pasca di Magliano
×Abstract
Osteocalcin is a hormone produced in bones by osteoblasts during bone formation. Numerous studies have demonstrated that adrenal gland–derived glucocorticoids inhibit osteocalcin production, which can ultimately cause deleterious bones loss. This loss establishes a unidirectional endocrine relationship between the adrenal glands and bone, however, whether osteocalcin reciprocally regulates glucocorticoid secretion remains unclear. In this issue of the JCI, Yadav and colleagues address how bone-derived osteocalcin influences adrenal organogenesis and function. Using a large variety of animal models, the authors established that embryonic osteocalcin signaling, specifically through the GPR158 receptor, regulates postnatal adrenal steroid concentrations throughout life. This work has translational potential, and we await future investigations that determine whether modulating osteocalcin levels could promote endogenous adrenocortical function in adrenocortical hypoplasia and glucocorticoid deficiency.
Authors
Typhanie Dumontet, Gary D. Hammer
×Abstract
A major goal of SARS-CoV-2 vaccination is the induction of neutralizing antibodies (nAbs) capable of blocking infection by preventing interaction of the SARS-CoV-2 Spike protein with ACE2 on target cells. Cocktails of monoclonal nAbs can reduce the risk of severe disease if administered early in infection. However, multiple variants of concern (VOCs) have arisen during the pandemic that may escape from nAbs. In this issue of the JCI, Jia Zou, Li Li, and colleagues used yeast display libraries to identify mAbs that bind to Spike proteins with a vast array of single amino acid substitutions. The authors identified mutation-resistant monoclonal nAbs for potential use as therapeutics. Multimerization further improved the potency of selected nAbs. These findings suggest a way forward in development of better nAb cocktails. However, the emergence of the highly mutated omicron (B.1.1.529) variant heightens the importance of finding effective anti–SARS-CoV-2 nAb therapeutics despite rapid viral evolution.
Authors
Ranjeet Singh Mahla, Lynn B. Dustin
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Research Articles
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Abstract
As life expectancy continues to increase, clinicians are challenged by age-related renal impairment that involves podocyte senescence and glomerulosclerosis. There is now compelling evidence that lithium has a potent antiaging activity that ameliorates brain aging and increases longevity in Drosophila and Caenorhabditis elegans. As the major molecular target of lithium action and a multitasking protein kinase recently implicated in a variety of renal diseases, glycogen synthase kinase 3β (GSK3β) is overexpressed and hyperactive with age in glomerular podocytes, correlating with functional and histological signs of kidney aging. Moreover, podocyte-specific ablation of GSK3β substantially attenuated podocyte senescence and glomerular aging in mice. Mechanistically, key mediators of senescence signaling, such as p16INK4A and p53, contain high numbers of GSK3β consensus motifs, physically interact with GSK3β, and act as its putative substrates. In addition, therapeutic targeting of GSK3β by microdose lithium later in life reduced senescence signaling and delayed kidney aging in mice. Furthermore, in psychiatric patients, lithium carbonate therapy inhibited GSK3β activity and mitigated senescence signaling in urinary exfoliated podocytes and was associated with preservation of kidney function. Thus, GSK3β appears to play a key role in podocyte senescence by modulating senescence signaling and may be an actionable senostatic target to delay kidney aging.
Authors
Yudong Fang, Bohan Chen, Zhangsuo Liu, Athena Y. Gong, William T. Gunning, Yan Ge, Deepak Malhotra, Amira F. Gohara, Lance D. Dworkin, Rujun Gong
×A metabolic biomarker predicts Parkinson’s disease at the early stages in patients and animal models
Abstract
Background Care management of Parkinson’s disease (PD) patients currently remains symptomatic, mainly because diagnosis relying on the expression of the cardinal motor symptoms is made too late. Earlier detection of PD therefore represents a key step for developing therapies able to delay or slow down its progression.Methods We investigated metabolic markers in 3 different animal models of PD, mimicking different phases of the disease assessed by behavioral and histological evaluation, and in 3 cohorts of de novo PD patients and matched controls (n = 129). Serum and brain tissue samples were analyzed by nuclear magnetic resonance spectroscopy and data submitted to advanced multivariate statistics.Results Our translational strategy reveals common metabolic dysregulations in serum of the different animal models and PD patients. Some of them were mirrored in the tissue samples, possibly reflecting pathophysiological mechanisms associated with PD development. Interestingly, some metabolic dysregulations appeared before motor symptom emergence and could represent early biomarkers of PD. Finally, we built a composite biomarker with a combination of 6 metabolites. This biomarker discriminated animals mimicking PD from controls, even from the first, nonmotor signs and, very interestingly, also discriminated PD patients from healthy subjects.Conclusion From our translational study, which included 3 animal models and 3 de novo PD patient cohorts, we propose a promising biomarker exhibiting a high accuracy for de novo PD diagnosis that may possibly predict early PD development, before motor symptoms appear.Funding French National Research Agency (ANR), DOPALCOMP, Institut National de la Santé et de la Recherche Médicale, Université Grenoble Alpes, Association France Parkinson.
Authors
David Mallet, Thibault Dufourd, Mélina Decourt, Carole Carcenac, Paola Bossù, Laure Verlin, Pierre-Olivier Fernagut, Marianne Benoit-Marand, Gianfranco Spalletta, Emmanuel L. Barbier, Sebastien Carnicella, Véronique Sgambato, Florence Fauvelle, Sabrina Boulet
×Abstract
Gastrointestinal motility disorders involve alterations to the structure and/or function of the enteric nervous system (ENS) but the causal mechanisms remain unresolved in most cases. Homeostasis and disease in the ENS are processes that are regulated by enteric glia. Signaling mediated through type I lysophosphatidic acid receptors (LPAR1) has recently emerged as an important mechanism that contributes to disease, in part, through effects on peripheral glial survival and function. Enteric glia express LPAR1 but its role in ENS function and motility disorders is unknown. We used a combination of genetic, immunohistochemical, calcium imaging, and in vivo pharmacological approaches to investigate the role of LPAR1 in enteric glia. LPAR1 was enriched in enteric glia in mice and humans and LPA stimulated intracellular calcium responses in enteric glia, subsequently recruiting activity in a subpopulation of myenteric neurons. Blocking LPAR1 in vivo with AM966 attenuated gastrointestinal motility in mice and produced marked enteric neuro- and gliopathy. Samples from humans with chronic intestinal pseudo-obstruction (CIPO), a severe motility disorder, showed reduced glial LPAR1 expression in the colon and ileum. These data suggest that enteric glial LPAR1 signaling regulates gastrointestinal motility through enteric glia and could contribute to severe motility disorders in humans such as CIPO.
Authors
Mohammad M. Ahmadzai, Jonathon L. McClain, Christine Dharshika, Luisa Seguella, Fiorella Giancola, Roberto De Giorgio, Brian D. Gulbransen
×Abstract
The chromosomal t(4;14) (p16;q32) translocation drives high expression of histone methyltransferase nuclear SET domain–containing 2 (NSD2) and plays vital roles in multiple myeloma (MM) evolution and progression. However, the mechanisms of NSD2-driven epigenomic alterations in chemoresistance to proteasome inhibitors (PIs) are not fully understood. Using a CRISPR/Cas9 sgRNA library in a bone marrow–bearing MM model, we found that hepatoma-derived growth factor 2 (HRP2) was a suppressor of chemoresistance to PIs and that its downregulation correlated with a poor response and worse outcomes in the clinic. We observed suppression of HRP2 in bortezomib-resistant MM cells, and knockdown of HRP2 induced a marked tolerance to PIs. Moreover, knockdown of HRP2 augmented H3K27me3 levels, consequentially intensifying transcriptome alterations promoting cell survival and restriction of ER stress. Mechanistically, HRP2 recognized H3K36me2 and recruited the histone demethylase MYC-induced nuclear antigen (MINA) to remove H3K27me3. Tazemetostat, a highly selective epigenetic inhibitor that reduces H3K27me3 levels, synergistically sensitized the anti-MM effects of bortezomib both in vitro and in vivo. Collectively, these results provide a better understanding of the origin of chemoresistance in patients with MM with the t(4;14) translocation and a rationale for managing patients with MM who have different genomic backgrounds.
Authors
Jingjing Wang, Xu Zhu, Lin Dang, Hongmei Jiang, Ying Xie, Xin Li, Jing Guo, Yixuan Wang, Ziyi Peng, Mengqi Wang, Jingya Wang, Sheng Wang, Qian Li, Yafei Wang, Qiang Wang, Lingqun Ye, Lirong Zhang, Zhiqiang Liu
×Abstract
Eltrombopag, an FDA-approved non-peptidyl thrombopoietin receptor agonist, is clinically used for the treatment of aplastic anemia, a disease characterized by hematopoietic stem cell failure and pancytopenia, to improve platelet counts and stem cell function. Eltrombopag treatment results in a durable trilineage hematopoietic expansion in patients. Some of the eltrombopag hematopoietic activity has been attributed to its off-target effects, including iron chelation properties. However, the mechanism of action for its full spectrum of clinical effects is still poorly understood. Here, we report that eltrombopag bound to the TET2 catalytic domain and inhibited its dioxygenase activity, which was independent of its role as an iron chelator. The DNA demethylating enzyme TET2, essential for hematopoietic stem cell differentiation and lineage commitment, is frequently mutated in myeloid malignancies. Eltrombopag treatment expanded TET2-proficient normal hematopoietic stem and progenitor cells, in part because of its ability to mimic loss of TET2 with simultaneous thrombopoietin receptor activation. On the contrary, TET inhibition in TET2 mutant malignant myeloid cells prevented neoplastic clonal evolution in vitro and in vivo. This mechanism of action may offer a restorative therapeutic index and provide a scientific rationale to treat selected patients with TET2 mutant–associated or TET deficiency–associated myeloid malignancies.
Authors
Yihong Guan, Metis Hasipek, Dongxu Jiang, Anand D. Tiwari, Dale R. Grabowski, Simona Pagliuca, Sunisa Kongkiatkamon, Bhumika Patel, Salendra Singh, Yvonne Parker, Thomas LaFramboise, Daniel Lindner, Mikkael A. Sekeres, Omar Y. Mian, Yogen Saunthararajah, Jaroslaw P. Maciejewski, Babal K. Jha
×Abstract
Infection with SARS-CoV-2, the causative agent of COVID-19, causes mild to moderate disease in most patients but carries a risk of morbidity and mortality. Seriously affected individuals manifest disorders of hemostasis and a cytokine storm, but it is not understood how these manifestations of severe COVID-19 are linked. Here, we showed that the SARS-CoV-2 spike protein engaged the CD42b receptor to activate platelets via 2 distinct signaling pathways and promoted platelet-monocyte communication through the engagement of P selectin/PGSL-1 and CD40L/CD40, which led to proinflammatory cytokine production by monocytes. These results explain why hypercoagulation, monocyte activation, and a cytokine storm are correlated in patients severely affected by COVID-19 and suggest a potential target for therapeutic intervention.
Authors
Tianyang Li, Yang Yang, Yongqi Li, Zhengmin Wang, Faxiang Ma, Runqi Luo, Xiaoming Xu, Guo Zhou, Jianhua Wang, Junqi Niu, Guoyue Lv, Ian N. Crispe, Zhengkun Tu
×Abstract
Mutations in TGF-β–activated kinase 1 binding protein 2 (TAB2) have been implicated in the pathogenesis of dilated cardiomyopathy and/or congenital heart disease in humans, but the underlying mechanisms are currently unknown. Here, we identified an indispensable role for TAB2 in regulating myocardial homeostasis and remodeling by suppressing receptor-interacting protein kinase 1 (RIPK1) activation and RIPK1-dependent apoptosis and necroptosis. Cardiomyocyte-specific deletion of Tab2 in mice triggered dilated cardiomyopathy with massive apoptotic and necroptotic cell death. Moreover, Tab2-deficient mice were also predisposed to myocardial injury and adverse remodeling after pathological stress. In cardiomyocytes, deletion of TAB2 but not its close homolog TAB3 promoted TNF-α–induced apoptosis and necroptosis, which was rescued by forced activation of TAK1 or inhibition of RIPK1 kinase activity. Mechanistically, TAB2 critically mediates RIPK1 phosphorylation at Ser321 via a TAK1-dependent mechanism, which prevents RIPK1 kinase activation and the formation of RIPK1-FADD-caspase-8 apoptotic complex or RIPK1-RIPK3 necroptotic complex. Strikingly, genetic inactivation of RIPK1 with Ripk1-K45A knockin effectively rescued cardiac remodeling and dysfunction in Tab2-deficient mice. Together, these data demonstrated that TAB2 is a key regulator of myocardial homeostasis and remodeling by suppressing RIPK1-dependent apoptosis and necroptosis. Our results also suggest that targeting RIPK1-mediated cell death signaling may represent a promising therapeutic strategy for TAB2 deficiency–induced dilated cardiomyopathy.
Authors
Haifeng Yin, Xiaoyun Guo, Yi Chen, Yachang Zeng, Xiaoliang Mo, Siqi Hong, Hui He, Jing Li, Rachel Steinmetz, Qinghang Liu
×Abstract
Patients with heart failure (HF) have augmented vascular tone, which increases cardiac workload, impairing ventricular output and promoting further myocardial dysfunction. The molecular mechanisms underlying the maladaptive vascular responses observed in HF are not fully understood. Vascular smooth muscle cells (VSMCs) control vasoconstriction via a Ca2+-dependent process, in which the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1) on the sarcoplasmic reticulum (SR) plays a major role. To dissect the mechanistic contribution of intracellular Ca2+ release to the increased vascular tone observed in HF, we analyzed the remodeling of IP3R1 in aortic tissues from patients with HF and from controls. VSMC IP3R1 channels from patients with HF and HF mice were hyperphosphorylated by both serine and tyrosine kinases. VSMCs isolated from IP3R1VSMC–/– mice exhibited blunted Ca2+ responses to angiotensin II (ATII) and norepinephrine compared with control VSMCs. IP3R1VSMC–/– mice displayed significantly reduced responses to ATII, both in vivo and ex vivo. HF IP3R1VSMC–/– mice developed significantly less afterload compared with HF IP3R1fl/fl mice and exhibited significantly attenuated progression toward decompensated HF and reduced interstitial fibrosis. Ca2+-dependent phosphorylation of the MLC by MLCK activated VSMC contraction. MLC phosphorylation was markedly increased in VSMCs from patients with HF and HF mice but reduced in VSMCs from HF IP3R1VSMC–/– mice and HF WT mice treated with ML-7. Taken together, our data indicate that VSMC IP3R1 is a major effector of increased vascular tone, which contributes to increased cardiac afterload and decompensation in HF.
Authors
Haikel Dridi, Gaetano Santulli, Jessica Gambardella, Stanislovas S. Jankauskas, Qi Yuan, Jingyi Yang, Steven Reiken, Xujun Wang, Anetta Wronska, Xiaoping Liu, Alain Lacampagne, Andrew R. Marks
×Abstract
Women have higher prevalence of asthma compared with men. In asthma, allergic airway inflammation is initiated by IL-33 signaling through ST2, leading to increased IL-4, IL-5, and IL-13 production and eosinophil infiltration. Foxp3+ Tregs suppress and ST2+ Tregs promote allergic airway inflammation. Clinical studies showed that the androgen dehydroepiandrosterone (DHEA) reduced asthma symptoms in patients, and mouse studies showed that androgen receptor (AR) signaling decreased allergic airway inflammation. Yet the impact of AR signaling on lung Tregs remains unclear. Using AR-deficient and Foxp3 fate-mapping mice, we determined that AR signaling increased Treg suppression during Alternaria extract (Alt Ext; allergen) challenge by stabilizing Foxp3+ Tregs and limiting the number of ST2+ ex-Tregs and IL-13+ Th2 cells and ex-Tregs. AR signaling also decreased Alt Ext–induced ST2+ Tregs in mice by limiting expression of Gata2, a transcription factor for ST2, and by decreasing Alt Ext–induced IL-33 production from murine airway epithelial cells. We confirmed our findings in human cells where 5α-dihydrotestosterone (DHT), an androgen, decreased IL-33–induced ST2 expression in lung Tregs and decreased Alt Ext–induced IL-33 secretion in human bronchial epithelial cells. Our findings showed that AR signaling stabilized Treg suppressive function, providing a mechanism for the sex difference in asthma.
Authors
Vivek D. Gandhi, Jacqueline-Yvonne Cephus, Allison E. Norlander, Nowrin U. Chowdhury, Jian Zhang, Zachary J. Ceneviva, Elie Tannous, Vasiliy V. Polosukhin, Nathan D. Putz, Nancy Wickersham, Amrit Singh, Lorraine B. Ware, Julie A. Bastarache, Ciara M. Shaver, Hong Wei Chu, R. Stokes Peebles Jr., Dawn C. Newcomb
×Abstract
Through their ability to regulate gene expression in most organs, glucocorticoid (GC) hormones influence numerous physiological processes and are therefore key regulators of organismal homeostasis. In bone, GC hormones inhibit expression of the hormone Osteocalcin for poorly understood reasons. Here, we show that in a classical endocrine feedback loop, osteocalcin in return enhanced the biosynthesis of GC as well as mineralocorticoid hormones (adrenal steroidogenesis) in rodents and primates. Conversely, inactivation of osteocalcin signaling in adrenal glands significantly impaired adrenal growth and steroidogenesis in mice. Embryo-made osteocalcin was necessary for normal Sf1 expression in fetal adrenal cells and adrenal cell steroidogenic differentiation and therefore determined the number of steroidogenic cells present in the adrenal glands of adult animals. Embryonic, not postnatal, osteocalcin also governed adrenal growth, adrenal steroidogenesis, blood pressure, electrolyte equilibrium, and the rise in circulating corticosterone levels during the acute stress response in adult offspring. This osteocalcin-dependent regulation of adrenal development and steroidogenesis occurred even in the absence of a functional hypothalamus/pituitary/adrenal axis and explains why osteocalcin administration during pregnancy promoted adrenal growth and steroidogenesis and improved the survival of adrenocorticotropic hormone signaling–deficient animals. This study reveals that a bone-derived embryonic hormone influences lifelong adrenal functions and organismal homeostasis in the mouse.
Authors
Vijay K. Yadav, Julian M. Berger, Parminder Singh, Perumal Nagarajan, Gerard Karsenty
×Targeting a proteolytic neoepitope on CUB domain containing protein 1 (CDCP1) for RAS-driven cancers
Abstract
Extracellular proteolysis is frequently dysregulated in disease and can generate proteoforms with unique neoepitopes not found in healthy tissue. Here, we demonstrate that Abs that selectively recognize a proteolytic neoepitope on CUB domain containing protein 1 (CDCP1) could enable more effective and safer treatments for solid tumors. CDCP1 is highly overexpressed in RAS-driven cancers, and its ectodomain is cleaved by extracellular proteases. Biochemical, biophysical, and structural characterization revealed that the 2 cleaved fragments of CDCP1 remain tightly associated with minimal proteolysis-induced conformational change. Using differential phage display, we generated recombinant Abs that are exquisitely selective to cleaved CDCP1 with no detectable binding to the uncleaved form. These Abs potently targeted cleaved CDCP1-expressing cancer cells as an Ab-drug conjugate, an Ab-radionuclide conjugate, and a bispecific T cell engager. In a syngeneic pancreatic tumor model, these cleaved-specific Abs showed tumor-specific localization and antitumor activity with superior safety profiles compared with a pan-CDCP1 approach. Targeting proteolytic neoepitopes could provide an orthogonal “AND” gate for improving the therapeutic index.
Authors
Shion A. Lim, Jie Zhou, Alexander J. Martinko, Yung-Hua Wang, Ekaterina V. Filippova, Veronica Steri, Donghui Wang, Soumya G. Remesh, Jia Liu, Byron Hann, Anthony A. Kossiakoff, Michael J. Evans, Kevin K. Leung, James A. Wells
×Abstract
Exposure to addictive substances impairs flexible decision making. Cognitive flexibility is mediated by striatal cholinergic interneurons (CINs). However, how chronic alcohol drinking alters cognitive flexibility through CINs remains unclear. Here, we report that chronic alcohol consumption and withdrawal impaired reversal of instrumental learning. Chronic alcohol consumption and withdrawal also caused a long-lasting (21 days) reduction of excitatory thalamic inputs onto CINs and reduced pause responses of CINs in the dorsomedial striatum (DMS). CINs are known to inhibit glutamatergic transmission in dopamine D1 receptor–expressing medium spiny neurons (D1-MSNs) but facilitate this transmission in D2-MSNs, which may contribute to flexible behavior. We discovered that chronic alcohol drinking impaired CIN-mediated inhibition in D1-MSNs and facilitation in D2-MSNs. Importantly, in vivo optogenetic induction of long-term potentiation of thalamostriatal transmission in DMS CINs rescued alcohol-induced reversal learning deficits. These results demonstrate that chronic alcohol drinking reduces thalamic excitation of DMS CINs, compromising their regulation of glutamatergic transmission in MSNs, which may contribute to alcohol-induced impairment of cognitive flexibility. These findings provide a neural mechanism underlying inflexible drinking in alcohol use disorder.
Authors
Tengfei Ma, Zhenbo Huang, Xueyi Xie, Yifeng Cheng, Xiaowen Zhuang, Matthew J. Childs, Himanshu Gangal, Xuehua Wang, Laura N. Smith, Rachel J. Smith, Yubin Zhou, Jun Wang
×Abstract
Many SARS-CoV-2 neutralizing antibodies (nAbs) lose potency against variants of concern. In this study, we developed 2 strategies to produce mutation-resistant antibodies. First, a yeast library expressing mutant receptor binding domains (RBDs) of the spike protein was utilized to screen for potent nAbs that are least susceptible to viral escape. Among the candidate antibodies, P5-22 displayed ultrahigh potency for virus neutralization as well as an outstanding mutation resistance profile. Additionally, P14-44 and P15-16 were recognized as mutation-resistant antibodies with broad betacoronavirus neutralization properties. P15-16 has only 1 binding hotspot, which is K378 in the RBD of SARS-CoV-2. The crystal structure of the P5-22, P14-44, and RBD ternary complex clarified the unique mechanisms that underlie the excellent mutation resistance profiles of these antibodies. Secondly, polymeric IgG enhanced antibody avidity by eliminating P5-22’s only hotspot, residue F486 in the RBD, thereby potently blocking cell entry by mutant viruses. Structural and functional analyses of antibodies screened using both potency assays and the yeast RBD library revealed rare, ultrapotent, mutation-resistant nAbs against SARS-CoV-2.
Authors
Jia Zou, Li Li, Peiyi Zheng, Wenhua Liang, Siyi Hu, Shuaixiang Zhou, Yanqun Wang, Jincun Zhao, Daopeng Yuan, Lu Liu, Dongdong Wu, Mengqiu Xu, Fangfang Zhang, Mengzhu Zhu, Zhihai Wu, Xiaochao Cao, Meng Ni, Xiaomin Ling, Yue Wu, Zhihui Kuang, Moyan Hu, Jianfeng Li, Xue Li, Xiling Guo, Tianmin Xu, Haiping Jiang, Changshou Gao, Michael Yu, Junjian Liu, Nanshan Zhong, Jianfeng Zhou, Jian-an Huang, Tengchuan Jin, Jianxing He
×Abstract
BACKGROUND Presbyosmia, or aging-related olfactory loss, occurs in a majority of humans over age 65 years, yet remains poorly understood, with no specific treatment options. The olfactory epithelium (OE) is the peripheral organ for olfaction and is subject to acquired damage, suggesting a likely site of pathology in aging. Adult stem cells reconstitute the neuroepithelium in response to cell loss under normal conditions. In aged OE, patches of respiratory-like metaplasia have been observed histologically, consistent with a failure in normal neuroepithelial homeostasis.Methods Accordingly, we have focused on identifying cellular and molecular changes in presbyosmic OE. The study combined psychophysical testing with olfactory mucosa biopsy analysis, single-cell RNA-Sequencing (scRNA-Seq), and culture studies.Results We identified evidence for inflammation-associated changes in the OE stem cells of presbyosmic patients. The presbyosmic basal stem cells exhibited increased expression of genes involved in response to cytokines or stress or the regulation of proliferation and differentiation. Using a culture model, we found that cytokine exposure drove increased TP63, a transcription factor acting to prevent OE stem cell differentiation.Conclusions Our data suggest aging-related inflammatory changes in OE stem cells may contribute to presbyosmia via the disruption of normal epithelial homeostasis. OE stem cells may represent a therapeutic target for restoration of olfaction.Funding NIH grants DC018371, NS121067, DC016224; Office of Physician-Scientist Development, Burroughs-Wellcome Fund Research Fellowship for Medical Students Award, Duke University School of Medicine.
Authors
Allison D. Oliva, Rupali Gupta, Khalil Issa, Ralph Abi Hachem, David W. Jang, Sebastian A. Wellford, E. Ashley Moseman, Hiroaki Matsunami, Bradley J. Goldstein
×Abstract
BACKGROUND The KRAS proto-oncogene is among the most frequently mutated genes in cancer, yet for 40 years it remained an elusive therapeutic target. Recently, allosteric inhibitors that covalently bind to KRAS G12C mutations have been approved for use in lung adenocarcinomas. Although responses are observed, they are often short-lived, thus making in-depth characterization of the mechanisms of resistance of paramount importance.METHODS Here, we present a rapid-autopsy case of a patient who had a KRASG12C-mutant lung adenocarcinoma who initially responded to a KRAS G12C inhibitor but then rapidly developed resistance. Using deep-RNA and whole-exome sequencing comparing pretreatment, posttreatment, and matched normal tissues, we uncover numerous mechanisms of resistance to direct KRAS inhibition.RESULTS In addition to decreased KRAS G12C–mutant allele frequency in refractory tumors, we also found reactivation of the MAPK pathway despite no new mutations in KRAS or its downstream mediators. Tumor cell–intrinsic and non–cell autonomous mechanisms included increased complement activation, coagulation, and tumor angiogenesis, and several lines of evidence of immunologic evasion.CONCLUSION Together, our findings reveal numerous mechanisms of resistance to current KRAS G12C inhibitors through enrichment of clonal populations, KRAS-independent downstream signaling, and diverse remodeling of the tumor microenvironment.FUNDING Richard and Fran Duley, Jimmy and Kay Mann, the NIH, and the North Carolina Biotechnology Center.
Authors
Yihsuan S. Tsai, Mark G. Woodcock, Salma H. Azam, Leigh B. Thorne, Krishna L. Kanchi, Joel S. Parker, Benjamin G. Vincent, Chad V. Pecot
×Abstract
BACKGROUND Curative gene therapies for sickle cell disease (SCD) are currently undergoing clinical evaluation. The occurrence of myeloid malignancies in these trials has prompted safety concerns. Individuals with SCD are predisposed to myeloid malignancies, but the underlying causes remain undefined. Clonal hematopoiesis (CH) is a premalignant condition that also confers significant predisposition to myeloid cancers. While it has been speculated that CH may play a role in SCD-associated cancer predisposition, limited data addressing this issue have been reported.METHODS Here, we leveraged 74,190 whole-genome sequences to robustly study CH in SCD. Somatic mutation calling methods were used to assess CH in all samples and comparisons between individuals with and without SCD were performed.RESULTS While we had sufficient power to detect a greater than 2-fold increased rate of CH, we found no detectable variation in rate or clone properties between individuals affected by SCD and controls. The rate of CH in individuals with SCD was unaltered by hydroxyurea use.CONCLUSIONS We did not observe an increased risk for acquiring detectable CH in SCD, at least as measured by whole-genome sequencing. These results should help guide ongoing efforts and further studies that seek to better define the risk factors underlying myeloid malignancy predisposition in SCD and help ensure that curative therapies can be more safely applied.FUNDING New York Stem Cell Foundation and the NIH.
Authors
L. Alexander Liggett, Liam D. Cato, Joshua S. Weinstock, Yingze Zhang, S. Mehdi Nouraie, Mark T. Gladwin, Melanie E. Garrett, Allison Ashley-Koch, Marilyn J. Telen, Brian Custer, Shannon Kelly, Carla L. Dinardo, Ester C. Sabino, Paula Loureiro, Anna B. Carneiro-Proietti, Cláudia Maximo, NHLBI Trans-Omics for Precision Medicine (TOPMed) Consortium, Alexander P. Reiner, Gonçalo R. Abecasis, David A. Williams, Pradeep Natarajan, Alexander G. Bick, Vijay G. Sankaran
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)