Cell biology
Abstract
The switch from anchorage-dependent to anchorage-independent growth is essential for epithelial metastasis. The underlying mechanism, however, is not fully understood. Here in this study, we identified growth factor independent-1 (GFI1), a transcription factor that drives transition from adherent endothelial cells to suspended hematopoietic cells during hematopoiesis, as a critical regulator of anchorage-independence in lung cancer cells. GFI1 elevated the numbers of circulating and lung infiltrating tumor cells in xenograft models and predicted poor prognosis of lung cancer patients. Mechanistically, GFI1 inhibited the expression of multiple adhesion molecules and facilitated substrate detachment. Concomitantly, GFI1 reconfigured chromatin structure of the RASGRP2 gene and increased its expression, causing Rap1 activation and subsequent sustained ERK activation upon detachment, and this leaded to ERK signaling dependency in tumor cells. Our studies unveiled a mechanism by which carcinoma cells hijacked a hematopoietic factor to gain anchorage independence and suggested that the intervention of ERK signaling may suppress metastasis and improve the therapeutic outcome of GFI1-positive lung cancer patients.
Authors
Hao Wang, Zhenzhen Lin, Zhe Nian, Wei Zhang, Wenxu Liu, Fei Yan, Zengtuan Xiao, Xia Wang, Zhenfa Zhang, Zhenyi Ma, Zhe Liu
Abstract
Lymph node (LN) fibroblastic reticular cells (FRCs) define LN niches and regulate lymphocyte homeostasis through producing diverse extracellular matrix (ECM) components. We examined the role of ECM laminin α4 (Lama4) using FRC-Lama4 conditional KO Pdgfrb-Cre–/– × Lama4fl/fl mice. Single-cell RNA-sequencing (scRNA-Seq) data showed the promoter gene Pdgfrb was exclusively expressed in FRCs. Depleting FRC-Lama4 reduced Tregs and dendritic cells, decreased high endothelial venules, impaired the conduit system, and downregulated T cell survival factors in LNs. FRC-Lama4 depletion impaired the homing of lymphocytes to LNs in homeostasis and after allografting. Alloantigen-specific T cells proliferated, were activated to greater degrees in LNs lacking FRC-Lama4, and were more prone to differentiate into effector phenotypes relative to the Treg phenotype. In murine cardiac transplantation, tolerogenic immunosuppression was not effective in FRC-Lama4 recipients, which produced more alloantibodies than WT. After lung transplantation, FRC-Lama4–KO mice had more severe graft rejection with fewer Tregs in their LNs. Overall, FRC-Lama4 critically contributes to a tolerogenic LN niche by supporting T cell migration, constraining T cell activation and proliferation, and promoting Treg differentiation. Hence, it serves as a therapeutic target for immunoengineering.
Authors
Lushen Li, Marina W. Shirkey, Tianshu Zhang, Wenji Piao, Xiaofei Li, Jing Zhao, Zhongcheng Mei, Yizhan Guo, Vikas Saxena, Allison Kensiski, Samuel J. Gavzy, Yang Song, Bing Ma, Jing Wu, Yanbao Xiong, Long Wu, Xiaoxuan Fan, Holly Roussey, Meng Li, Alexæander S. Krupnick, Reza Abdi, Jonathan S. Bromberg
Abstract
Maladaptive changes of nerve injury–associated genes in dorsal root ganglia (DRGs) are critical for neuropathic pain genesis. Emerging evidence supports the role of long noncoding RNAs (lncRNAs) in regulating gene transcription. Here we identified a conserved lncRNA, named nerve injury–specific lncRNA (NIS-lncRNA) for its upregulation in injured DRGs exclusively in response to nerve injury. This upregulation was triggered by nerve injury–induced increase in DRG ELF1, a transcription factor that bound to the NIS-lncRNA promoter. Blocking this upregulation attenuated nerve injury–induced CCL2 increase in injured DRGs and nociceptive hypersensitivity during the development and maintenance periods of neuropathic pain. Mimicking NIS-lncRNA upregulation elevated CCL2 expression, increased CCL2-mediated excitability in DRG neurons, and produced neuropathic pain symptoms. Mechanistically, NIS-lncRNA recruited more binding of the RNA-interacting protein FUS to the Ccl2 promoter and augmented Ccl2 transcription in injured DRGs. Thus, NIS-lncRNA participates in neuropathic pain likely by promoting FUS-triggered DRG Ccl2 expression and may be a potential target in neuropathic pain management.
Authors
Shibin Du, Shaogen Wu, Xiaozhou Feng, Bing Wang, Shangzhou Xia, Lingli Liang, Li Zhang, Gokulapriya Govindarajalu, Alexander Bunk, Feni Kadakia, Qingxiang Mao, Xinying Guo, Hui Zhao, Tolga Berkman, Tong Liu, Hong Li, Jordan Stillman, Alex Bekker, Steve Davidson, Yuan-Xiang Tao
Abstract
Acquired resistance is inevitable in non-small cell lung cancers (NSCLCs) treated with osimertinib (OSI), and the mechanisms are not well defined. The MERTK ligand GAS6 promoted downstream oncogenic signaling in EGFR-mutated (EGFRMT) NSCLC cells treated with OSI, suggesting a role for MERTK activation in OSI resistance. Indeed, treatment with MRX-2843, a first-in-class MERTK kinase inhibitor, re-sensitized GAS6-treated NSCLC cells to OSI. Both GAS6 and EGF stimulated downstream PI3K-AKT and MAPK-ERK signaling in parental cells, but only GAS6 activated these pathways in OSI resistant (OSIR) derivative cell lines. Functionally, OSIR cells were more sensitive to MRX-2843 than parental cells, suggesting acquired dependence on MERTK signaling. Furthermore, MERTK and/or its ligands were dramatically upregulated in EGFRMT tumors after treatment with OSI in both xenograft models and patient samples, consistent with induction of autocrine/paracrine MERTK activation. Moreover, treatment with MRX-2843 in combination with OSI, but not OSI alone, provided durable suppression of tumor growth in vivo, even after treatment was stopped. These data identify MERTK as a driver of bypass signaling in treatment-naïve and EGFRMT-OSIR NSCLC cells and predict that MRX-2843 and OSI combination therapy will provide clinical benefit in patients with EGFRMT NSCLC.
Authors
Dan Yan, Justus M. Huelse, Dmitri Kireev, Zikang Tan, Luxiao Chen, Subir Goyal, Xiaodong Wang, Stephen V. Frye, Madhusmita Behera, Frank Schneider, Suresh S. Ramalingam, Taofeek K. Owonikoko, H. Shelton Earp, Deborah DeRyckere, Douglas K. Graham
Abstract
The crosstalk between the BM microenvironment (niche) and hematopoietic stem cells (HSCs) is critical for HSC regeneration. Here, we show that in mice, deletion of the Fanconi anemia (FA) genes Fanca and Fancc dampened HSC regeneration through direct effects on HSCs and indirect effects on BM niche cells. FA HSCs showed persistent upregulation of the Wnt target Prox1 in response to total body irradiation (TBI). Accordingly, lineage-specific deletion of Prox1 improved long-term repopulation of the irradiated FA HSCs. Forced expression of Prox1 in WT HSCs mimicked the defective repopulation phenotype of FA HSCs. WT mice but not FA mice showed significant induction by TBI of BM stromal Wnt5a protein. Mechanistically, FA proteins regulated stromal Wnt5a expression, possibly through modulating the Wnt5a transcription activator Pax2. Wnt5a treatment of irradiated FA mice enhanced HSC regeneration. Conversely, Wnt5a neutralization inhibited HSC regeneration after TBI. Wnt5a secreted by LepR+CXCL12+ BM stromal cells inhibited β-catenin accumulation, thereby repressing Prox1 transcription in irradiated HSCs. The detrimental effect of deregulated Wnt5a/Prox1 signaling on HSC regeneration was also observed in patients with FA and aged mice. Irradiation induced upregulation of Prox1 in the HSCs of aged mice, and deletion of Prox1 in aged HSCs improved HSC regeneration. Treatment of aged mice with Wnt5a enhanced hematopoietic repopulation. Collectively, these findings identified the paracrine Wnt5a/Prox1 signaling axis as a regulator of HSC regeneration under conditions of injury and aging.
Authors
Qiqi Lin, Limei Wu, Srinivas Chatla, Fabliha A. Chowdhury, Neha Atale, Jonathan Joseph, Wei Du
Abstract
Mitochondrial stress triggers a response in the cell’s mitochondria and nucleus, but how these stress responses are coordinated in vivo is poorly understood. Here, we characterize a family with myopathy caused by a dominant p.G58R mutation in the mitochondrial protein CHCHD10. To understand the disease etiology, we developed a knock-in mouse model and found that mutant CHCHD10 aggregates in affected tissues, applying a toxic protein stress to the inner mitochondrial membrane. Unexpectedly, survival of CHCHD10 knock-in mice depended on a protective stress response mediated by OMA1. The OMA1 stress response acted both locally within mitochondria, causing mitochondrial fragmentation, and signaled outside the mitochondria, activating the integrated stress response through cleavage of DELE1. We additionally identified an isoform switch in the terminal complex of the electron transport chain as a component of this response. Our results demonstrate that OMA1 is critical for neonatal survival conditionally in the setting of inner mitochondrial membrane stress, coordinating local and global stress responses to reshape the mitochondrial network and proteome.
Authors
Mario K. Shammas, Xiaoping Huang, Beverly P. Wu, Evelyn Fessler, Insung Song, Nicholas P. Randolph, Yan Li, Christopher K.E. Bleck, Danielle A. Springer, Carl Fratter, Ines A. Barbosa, Andrew F. Powers, Pedro M. Quirós, Carlos Lopez-Otin, Lucas T. Jae, Joanna Poulton, Derek P. Narendra
Abstract
Mitochondrial proteostasis, regulated by the mitochondrial unfolded protein response (UPRmt), is crucial for maintenance of cellular functions and survival. Elevated oxidative and proteotoxic stress in mitochondria must be attenuated by the activation of ubiquitous UPRmt to promote prostate cancer (PCa) growth. Here we show that the two key components of the UPRmt, heat shock protein 60 (HSP60, a mitochondrial chaperonin) and caseinolytic protease (ClpP, a mitochondrial protease) were required for the development of advanced PCa. HSP60 regulated ClpP expression via c-Myc and physically interacted with ClpP to restore mitochondrial functions promoting cancer cell survival. HSP60 maintained the ATP-producing functions of mitochondria, which activated β-catenin pathway leading to the upregulation of c-Myc. We identified an UPRmt inhibitor that blocked HSP60 interaction with ClpP and abrogated survival signaling without altering HSP60 chaperonin function. Disruption of HSP60-ClpP interaction by UPRmt inhibitor triggered metabolic stress and impeded PCa promoting signaling. Treatment with UPRmt inhibitor, or genetic ablation of Hsp60, inhibited PCa growth and progression. Together, our findings identify that HSP60-ClpP mediated UPRmt is essential for prostate tumorigenesis and HSP60-ClpP interaction represents a therapeutic vulnerability in PCa.
Authors
Rahul Kumar, Ajay Kumar Chaudhary, Jordan Woytash, Joseph R. Inigo, Abhiram A. Gokhale, Wiam Bshara, Kristopher Attwood, Jianmin Wang, Joseph A. Spernyak, Eva Rath, Neelu Yadav, Dirk Haller, David W. Goodrich, Dean G. Tang, Dhyan Chandra
Abstract
Poly(ADP-ribose) polymerase inhibitors (PARP inhibitors) have had an increasing role in the treatment of ovarian and breast cancers. PARP inhibitors are selectively active in cells with homologous recombination DNA repair deficiency caused by mutations in BRCA1/2 and other DNA repair pathway genes. Cancers with homologous recombination DNA repair proficiency respond poorly to PARP inhibitors. Cancers that initially respond to PARP inhibitors eventually develop drug resistance. We have identified salt-inducible kinase 2 (SIK2) inhibitors, ARN3236 and ARN3261, which decreased DNA double-strand break (DSB) repair functions and produced synthetic lethality with multiple PARP inhibitors in both homologous recombination DNA repair deficiency and proficiency cancer cells. SIK2 is required for centrosome splitting and PI3K activation and regulates cancer cell proliferation, metastasis, and sensitivity to chemotherapy. Here, we showed that SIK2 inhibitors sensitized ovarian and triple-negative breast cancer (TNBC) cells and xenografts to PARP inhibitors. SIK2 inhibitors decreased PARP enzyme activity and phosphorylation of class-IIa histone deacetylases (HDAC4/5/7). Furthermore, SIK2 inhibitors abolished class-IIa HDAC4/5/7–associated transcriptional activity of myocyte enhancer factor-2D (MEF2D), decreasing MEF2D binding to regulatory regions with high chromatin accessibility in FANCD2, EXO1, and XRCC4 genes, resulting in repression of their functions in the DNA DSB repair pathway. The combination of PARP inhibitors and SIK2 inhibitors provides a therapeutic strategy to enhance PARP inhibitor sensitivity for ovarian cancer and TNBC.
Authors
Zhen Lu, Weiqun Mao, Hailing Yang, Janice M. Santiago-O’Farrill, Philip J. Rask, Jayanta Mondal, Hu Chen, Cristina Ivan, Xiuping Liu, Chang-Gong Liu, Yuanxin Xi, Kenta Masuda, Eli M. Carrami, Meng Chen, Yitao Tang, Lan Pang, David S. Lakomy, George A. Calin, Han Liang, Ahmed A. Ahmed, Hariprasad Vankayalapati, Robert C. Bast Jr.
Abstract
The relevance of molecular mechanisms governing mitochondrial proteostasis to the differentiation and function of hematopoietic and immune cells is largely elusive. Through dissection of the network of proteins related to HCLS1-associated protein X-1, we defined a potentially novel functional CLPB/HAX1/(PRKD2)/HSP27 axis with critical importance for the differentiation of neutrophil granulocytes and, thus, elucidated molecular and metabolic mechanisms underlying congenital neutropenia in patients with HAX1 deficiency as well as bi- and monoallelic mutations in CLPB. As shown by stable isotope labeling by amino acids in cell culture (SILAC) proteomics, CLPB and HAX1 control the balance of mitochondrial protein synthesis and persistence crucial for proper mitochondrial function. Impaired mitochondrial protein dynamics are associated with decreased abundance of the serine-threonine kinase PRKD2 and HSP27 phosphorylated on serines 78 and 82. Cellular defects in HAX1–/– cells can be functionally reconstituted by HSP27. Thus, mitochondrial proteostasis emerges as a critical molecular and metabolic mechanism governing the differentiation and function of neutrophil granulocytes.
Authors
Yanxin Fan, Marta Murgia, Monika I. Linder, Yoko Mizoguchi, Cong Wang, Marcin Łyszkiewicz, Natalia Ziȩtara, Yanshan Liu, Stephanie Frenz, Gabriela Sciuccati, Armando Partida-Gaytan, Zahra Alizadeh, Nima Rezaei, Peter Rehling, Sven Dennerlein, Matthias Mann, Christoph Klein
Abstract
Mushroom spine loss and calcium dyshomeostasis are early hallmark events of age-related neurodegeneration, such as Alzheimer’s disease (AD), that are connected with neuronal hyperactivity in early pathology of cognitive brain areas. However, it remains elusive how these key events are triggered at the molecular level for the neuronal abnormality that occurs at the initial stage of disease. Here, we identify downregulated miR-339-5p and its upregulated target protein, neuronatin (Nnat), in cortex neurons from the presenilin-1 M146V knockin (PSEN1-M146V KI) mouse model of familial AD (FAD). Inhibition of miR-339-5p or overexpression of Nnat recapitulates spine loss and endoplasmic reticulum calcium overload in cortical neurons with the PSEN1 mutation. Conversely, either overexpression of miR-339-5p or knockdown of Nnat restores spine morphogenesis and calcium homeostasis. We used fiber photometry recording during the object-cognitive process to further demonstrate that the PSEN1 mutant causes defective habituation in neuronal reaction in the retrosplenial cortex and that this can be rescued by restoring the miR-339-5p/Nnat pathway. Our findings thus reveal crucial roles of the miR-339-5p/Nnat pathway in FAD that may serve as potential diagnostic and therapeutic targets for early pathogenesis.
Authors
Hao-Yu Zou, Lin Guo, Bei Zhang, Si Chen, Xin-Rong Wu, Xian-Dong Liu, Xin-Yu Xu, Bin-Yin Li, Shengdi Chen, Nan-Jie Xu, Suya Sun
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Copyright © 2022 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)