Cell biology
Abstract
Hormone receptor-positive and human epidermal growth factor receptor 2-negative breast cancer (HR+/HER2− BC) is the most common subtype, with high risk of long-term recurrence and metastasis. Endocrine therapy (ET) combined with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors is a standard treatment for advanced/metastatic HR+/HER2- BC, but resistance remains a major clinical challenge. We report that kinesin family member C2 (KIFC2) was amplified in approximately 50% HR+/HER2- BC, and its high expression was associated with poor disease outcome, increased tumor protein p53 (TP53) somatic mutation, and active pyrimidine metabolism. Function assays revealed that depletion of KIFC2 suppressed growth and enhanced sensitivity of HR+/HER2- BC cells to tamoxifen and CDK4/6 inhibitors. Mechanistically, KIFC2 stabilized CDK4 by enhancing its interaction with ubiquitin specific peptidase 9 X-linked (USP9X). Importantly, re-expression of CDK4 in KIFC2-depleted cells partially rescued the decreased growth and increased sensitivity to tamoxifen and CDK4/6 inhibitors caused by KIFC2 depletion. Clinically, high KIFC2 mRNA expression was negatively associated with survival rate of HR+/HER2- BC patients received adjuvant ET alone or in combination with CDK4/6 inhibitors. Collectively, these findings identify an important role for KIFC2 in HR+/HER2- BC growth and therapeutic resistance, and support its potential as a therapeutic target and predictive biomarker.
Authors
Shao-Ying Yang, Ming-Liang Jin, Lisa Andriani, Qian Zhao, Yun-Xiao Ling, Cai-Jin Lin, Min-Ying Huang, Jia-Yang Cai, Yin-Ling Zhang, Xin Hu, Zhi-Ming Shao, Fang-Lin Zhang, Xi Jin, A Yong Cao, Da-Qiang Li
Abstract
The Fanconi anemia (FA)/BRCA DNA repair network promotes the removal of DNA interstrand crosslinks (ICLs) to counteract their devastating consequences, including oncogenesis. Network signaling is initiated by the FA core complex, which consists of seven authentic FA proteins and an FA-associated protein, FAAP100, with incompletely characterized roles and unknown disease associations. Upon activation, the FA core complex functions as a multiprotein E3 ubiquitin ligase centered on its catalytic module, the FANCB-FANCL-FAAP100 (BLP100) subcomplex, for FANCD2 and FANCI monoubiquitylation. Here, we identified a homozygous variant in FAAP100, c.1642A>C, predicting p.(T542P), in a fetus with malformations suggestive of FA. The mutation causes sensitivity to ICL-inducing agents in cells from the affected individual and genetically engineered, FAAP100-inactivated human, avian, zebrafish, and mouse cells. All FAAP100-deficient cell types were rescued by ectopic expression of wild-type FAAP100, but not FAAP100T542P. In a confirmatory animal model, customized Faap100–/– mice exhibit embryonic lethality, microsomia, malformations, and gonadal atrophy resembling mice with established FA subtypes. Mechanistically, FAAP100T542P impairs ligase activity by preventing BLP100 subcomplex formation, resulting in defective FAAP100T542P nuclear translocation and chromatin recruitment. FAAP100 dysfunction that disrupts the FA pathway and impairs genomic maintenance, together with FAconsistent human manifestations, recommends FAAP100 as a legitimate FA gene, FANCX.
Authors
Julia Kuehl, Yutong Xue, Fenghua Yuan, Ramanagouda Ramanagoudr-Bhojappa, Simone Pickel, Reinhard Kalb, Settara C. Chandrasekharappa, Weidong Wang, Yanbin Zhang, Detlev Schindler
Abstract
In the kidney, cells of thick ascending limb of the loop of Henle (TAL) are resistant to ischemic injury, despite high energy demands. This adaptive metabolic response is not fully understood even though the integrity of TAL cells is essential for recovery from acute kidney injury (AKI). TAL cells uniquely express uromodulin, the most abundant protein secreted in healthy urine. Here, we demonstrate that alternative splicing generates a conserved intracellular isoform of uromodulin, which contributes to metabolic adaptation of TAL cells. This splice variant was induced by oxidative stress and was up-regulated by AKI that is associated with recovery, but not by severe AKI and chronic kidney disease (CKD). This intracellular variant was targeted to the mitochondria, increased NAD+ and ATP levels, and protected TAL cells from hypoxic injury. Augmentation of this variant using antisense oligonucleotides after severe AKI improved the course of injury. These findings underscore an important role of condition-specific alternative splicing in adaptive energy metabolism to hypoxic stress. Enhancing this protective splice variant in TAL cells could become a novel therapeutic intervention for AKI.
Authors
Azuma Nanamatsu, George J. Rhodes, Kaice A. LaFavers, Radmila Micanovic, Virginie Lazar, Shehnaz Khan, Daria Barwinska, Shinichi Makino, Amy Zollman, Ying-Hua Cheng, Emma H. Doud, Amber L. Mosley, Matthew J. Repass, Malgorzata M. Kamocka, Aravind Baride, Carrie L. Phillips, Katherine J. Kelly, Michael T. Eadon, Jonathan Himmelfarb, Matthias Kretzler, Robert L. Bacallao, Pierre C. Dagher, Takashi Hato, Tarek M. El-Achkar
Abstract
Type 2 innate lymphoid cells (ILC2) regulate the proliferation of preadipocytes that give rise to beige adipocytes. Whether and how ILC2 downstream Th2 cytokines control beige adipogenesis remain unclear. We employed cell systems and genetic models to examine the mechanism through which interleukin-13 (IL-13), an ILC2-derived Th2 cytokine, controls beige adipocyte differentiation. IL-13 priming in preadipocytes drives beige adipogenesis by upregulating beige-promoting metabolic programs, including mitochondrial oxidative metabolism and PPARγ-related pathways. The latter is mediated by increased expression and activity of PPARγ through IL-13 receptor α1 (IL-13Rα1) downstream effectors, STAT6 and p38 MAPK, respectively. Il13 knockout (Il13KO) or preadipocyte Il13ra1 knockout (Il13ra1KO) mice are refractory to cold- or β-3 adrenergic agonist-induced beiging in inguinal white adipose tissue, whereas Il4 knockout mice show no defects in beige adipogenesis. Il13KO and Il13ra1KO mouse models exhibit increased body weight/fat mass and dysregulated glucose metabolism but have a mild cold intolerant phenotype, likely due to their intact brown adipocyte recruitment. We also find that genetic variants of human IL13RA1 are associated with body mass index and type 2 diabetes. These results suggest that IL-13 signaling-regulated beige adipocyte function may play a predominant role in modulating metabolic homeostasis rather than in thermoregulation.
Authors
Alexandra R. Yesian, Mayer M. Chalom, Nelson H. Knudsen, Alec L. Hyde, Jean Personnaz, Hyunjii Cho, Yae-Huei Liou, Kyle A. Starost, Chia-Wei Lee, Dong-Yan Tsai, Hsing-Wei Ho, Jr-Shiuan Lin, Jun Li, Frank B. Hu, Alexander S. Banks, Chih-Hao Lee
Abstract
Acute myeloid leukemia (AML) is an aggressive and often deadly malignancy associated with proliferative immature myeloid blasts. Here, we identified CD84 as a critical survival regulator in AML. High levels of CD84 expression provided a survival advantage to leukemia cells, whereas CD84 downregulation disrupted their proliferation, clonogenicity and engraftment capabilities in both human cell lines and patient derived xenograft cells. Critically, loss of CD84 also markedly blocked leukemia engraftment and clonogenicity in MLL-AF9 and inv(16) AML mouse models, highlighting its pivotal role as survival factor across species. Mechanistically, CD84 regulated leukemia cells’ energy metabolism and mitochondrial dynamics. Depletion of CD84 altered mitochondrial ultra-structure and function of leukemia cells, and it caused down-modulation of both oxidative phosphorylation and fatty acid oxidation pathways. CD84 knockdown induced a block of Akt phosphorylation and down-modulation of nuclear factor erythroid 2-related factor 2 (NRF2), impairing AML antioxidant defense. Conversely, CD84 over-expression stabilized NRF2 and promoted its transcriptional activation, thereby supporting redox homeostasis and mitochondrial function in AML. Collectively, our findings indicated that AML cells depend on CD84 to support antioxidant pro-survival pathways, highlighting a therapeutic vulnerability of leukemia cells.
Authors
Yinghui Zhu, Mariam Murtadha, Miaomiao Liu, Enrico Caserta, Ottavio Napolitano, Le Xuan Truong Nguyen, Huafeng Wang, Milad Moloudizargari, Lokesh Nigam, Theophilus Tandoh, Xuemei Wang, Alex Pozhitkov, Rui Su, Xiangjie Lin, Marc Denisse Estepa, Raju Pillai, Joo Song, James F. Sanchez, Yu-Hsuan Fu, Lianjun Zhang, Man Li, Bin Zhang, Ling Li, Ya-Huei Kuo, Steven Rosen, Guido Marcucci, John C. Williams, Flavia Pichiorri
Abstract
Hyaluronan (HA) in the extracellular matrix promotes epithelial-to-mesenchymal transition (EMT) and metastasis; however, the mechanism by which the HA network constructed by cancer cells regulates cancer progression and metastasis in the tumor microenvironment (TME) remains largely unknown. In this study, inter-alpha-trypsin inhibitor heavy chain 2 (ITIH2), an HA-binding protein, was confirmed to be secreted from mesenchymal-like lung cancer cells when co-cultured with cancer-associated fibroblasts. ITIH2 expression is transcriptionally upregulated by the EMT-inducing transcription factor ZEB1, along with HA synthase 2 (HAS2), which positively correlates with ZEB1 expression. Depletion of ITIH2 and HAS2 reduced HA matrix formation and the migration and invasion of lung cancer cells. Furthermore, ZEB1 facilitates alternative splicing and isoform expression of CD44, an HA receptor, and CD44 knockdown suppresses the motility and invasiveness of lung cancer cells. Using a deep learning-based drug-target interaction algorithm, we identified an ITIH2 inhibitor (sincalide) that inhibited HA matrix formation and migration of lung cancer cells, preventing metastatic colonization of lung cancer cells in mouse models. These findings suggest that ZEB1 remodels the HA network in the TME through the regulation of ITIH2, HAS2, and CD44, presenting a strategy for targeting this network to suppress lung cancer progression.
Authors
Sieun Lee, Jihye Park, Seongran Cho, Eun Ju Kim, Seonyeong Oh, Younseo Lee, Sungsoo Park, Keunsoo Kang, Dong Hoon Shin, Song Yi Ko, Jonathan M. Kurie, Young-Ho Ahn
Abstract
Lysyl hydroxylase 2 (LH2) is highly expressed in multiple tumor types and accelerates disease progression by hydroxylating lysine residues on fibrillar collagen telopeptides to generate stable collagen cross links in tumor stroma. Here, we show that a galactosylhydroxylysyl glucosyltransferase (GGT) domain on LH2-modified type-VI collagen (Col6) to promote lung adenocarcinoma (LUAD) growth and metastasis. In tumors generated by LUAD cells lacking LH2 GGT domain activity, stroma was less stiff, and stable types of collagen cross links were reduced. Mass spectrometric analysis of total and glycosylated peptides in parental and GGT-inactive tumor samples identified Col6 chain α3 (Col6a3), a component of the Col6 heterotrimeric molecule, as a candidate LH2 substrate. In gain- and loss-of-function studies, high Col6a3 levels increased tumor growth and metastatic activity and enhanced the proliferative, migratory, and invasive activities of LUAD cells. LH2 coimmunoprecipitated with Col6a3, and LH2 glucosylated Col6 in an in vitro reaction. Glucosylation increased the integrin-binding and promigratory activities of Col6 in LUAD cells. Col6a3 K2049 was deglucosylated in GGT-inactive tumor samples, and mutagenesis of Col6a3 K2049 phenocopied Col6a3 deficiency or LH2 GGT domain inactivation in LUAD cells. Thus, LH2 glucosylates Col6 to drive LUAD progression. These findings show that the GGT domain of LH2 is protumorigenic, identify Col6 as a candidate effector, and provide a rationale to develop pharmacological strategies that target LH2’s GGT domain in cancer cells.
Authors
Shike Wang, Houfu Guo, Reo Fukushima, Masahiko Terajima, Min Liu, Guan-Yu Xiao, Lenka Koudelková, Chao Wu, Xin Liu, Jiang Yu, Emma Burris, Jun Xu, Alvise Schiavinato, William K. Russell, Mitsuo Yamauchi, Xiaochao Tan, Jonathan M. Kurie
Abstract
Mitochondrial dysfunction fuels vascular inflammation and atherosclerosis. Mitochondrial calcium uptake 1 (MICU1) maintains mitochondrial Ca2+ homeostasis. However, the role of MICU1 in vascular inflammation and atherosclerosis remains unknown. Here, we report that endothelial MICU1 prevents vascular inflammation and atherosclerosis by maintaining mitochondrial homeostasis. We observed that vascular inflammation was aggravated in endothelial cell–specific Micu1 knockout mice (Micu1ECKO) and attenuated in endothelial cell–specific Micu1 transgenic mice (Micu1ECTg). Furthermore, hypercholesterolemic Micu1ECKO mice also showed accelerated development of atherosclerosis, while Micu1ECTg mice were protected against atherosclerosis. Mechanistically, MICU1 depletion increased mitochondrial Ca2+ influx, thereby decreasing the expression of the mitochondrial deacetylase sirtuin 3 (SIRT3) and the ensuing deacetylation of superoxide dismutase 2 (SOD2), leading to the burst of mitochondrial reactive oxygen species (mROS). Of clinical relevance, we observed decreased MICU1 expression in the endothelial layer covering human atherosclerotic plaques and in human aortic endothelial cells exposed to serum from patients with coronary artery diseases (CAD). Two-sample Wald ratio Mendelian randomization further revealed that increased expression of MICU1 was associated with decreased risk of CAD and coronary artery bypass grafting (CABG). Our findings support MICU1 as an endogenous endothelial resilience factor that protects against vascular inflammation and atherosclerosis by maintaining mitochondrial Ca2+ homeostasis.
Authors
Lu Sun, Ruixue Leng, Monan Liu, Meiming Su, Qingze He, Zhidan Zhang, Zhenghong Liu, Zhihua Wang, Hui Jiang, Li Wang, Shuai Guo, Yiming Xu, Yuqing Huo, Clint L. Miller, Maciej Banach, Yu Huang, Paul C. Evans, Jaroslav Pelisek, Giovanni G. Camici, Bradford C. Berk, Stefan Offermanns, Junbo Ge, Suowen Xu, Jianping Weng
Abstract
Protein arginine methyl transferases (PRMTs) are generally upregulated in cancers. However, the mechanisms leading to this upregulation and its biological consequences are poorly understood. Here, we identify PRMT5, the main symmetric arginine methyltransferase, as a critical driver of chemoresistance in high-grade serous ovarian cancer (HGSOC). PRMT5 levels and its enzymatic activity are induced in a platinum-resistant (Pt-resistant) state at the protein level. To reveal potential regulators of high PRMT5 protein levels, we optimized intracellular immunostaining conditions and performed unbiased CRISPR screening. We identified Kelch-like ECH-associated protein 1 (KEAP1) as a top-scoring negative regulator of PRMT5. Our mechanistic studies show that KEAP1 directly interacted with PRMT5, leading to its ubiquitin-dependent degradation under normal physiological conditions. At the genomic level, ChIP studies showed that elevated PRMT5 directly interacted with the promoters of stress response genes and positively regulated their transcription. Combined PRMT5 inhibition with Pt resulted in synergistic cellular cytotoxicity in vitro and reduced tumor growth in vivo in Pt-resistant patient-derived xenograft tumors. Overall, the findings from this study identify PRMT5 as a critical therapeutic target in Pt-resistant HGSOC cells and reveal the molecular mechanisms that lead to high PRMT5 levels in Pt-treated and chemo-resistant tumors.
Authors
Harun Ozturk, Fidan Seker-Polat, Neda Abbaszadeh, Yasemin Kingham, Sandra Orsulic, Mazhar Adli
Abstract
Although refrigerated storage slows the metabolism of volunteer donor RBCs, which is essential in transfusion medicine, cellular aging still occurs throughout this in vitro process. Storage-induced microerythrocytes (SMEs) are morphologically-altered senescent RBCs that accumulate during storage and are cleared from circulation following transfusion. However, the molecular and cellular alterations that trigger clearance of this RBC subset remain to be identified. Using a staining protocol that sorts long-stored SMEs (i.e., CFSEhigh) and morphologically-normal RBCs (CFSElow), these in vitro aged cells were characterized. Metabolomics analysis identified depletion of energy, lipid-repair, and antioxidant metabolites in CFSEhigh RBCs. By redox proteomics, irreversible protein oxidation primarily affected CFSEhigh RBCs. By proteomics, 96 proteins, mostly in the proteostasis family, had relocated to CFSEhigh RBC membranes. CFSEhigh RBCs exhibited decreased proteasome activity and deformability; increased phosphatidylserine exposure, osmotic fragility, and endothelial cell adherence; and were cleared from the circulation during human spleen perfusion ex vivo. Conversely, molecular, cellular, and circulatory properties of long-stored CFSElow RBCs resembled those of short-stored RBCs. CFSEhigh RBCs are morphologically and metabolically altered, have irreversibly oxidized and membrane-relocated proteins, and exhibit decreased proteasome activity. In vitro aging during storage selectively alters metabolism and proteostasis in these storage-induced senescent RBCs targeted for clearance.
Authors
Sandy Peltier, Mickaël Marin, Monika Dzieciatkowska, Michaël Dussiot, Micaela Kalani Roy, Johanna Bruce, Louise Leblanc, Youcef Hadjou, Sonia Georgeault, Aurélie Fricot, Camille Roussel, Daniel Stephenson, Madeleine Casimir, Abdoulaye Sissoko, François Paye, Safi Dokmak, Papa Alioune Ndour, Philippe Roingeard, Emilie-Fleur Gautier, Steven L. Spitalnik, Olivier Hermine, Pierre A. Buffet, Angelo D’Alessandro, Pascal Amireault
No posts were found with this tag.
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)