Cellular & Molecular Biology Letters最新文献

Most of the canonical Arg-Gly-Asp (RGD)-containing integrin ligands are extracellular matrix proteins, such as fibronectin, vitronectin and fibrinogen, which regulate cell-ECM adhesion processes. However, during the last years, several reports have demonstrated the existence of non-canonical RGD-containing integrin ligands that are cell surface transmembrane proteins. At variance with the canonical extracellular matrix integrin ligands, the RGD-containing cell surface integrin ligands are involved in cell-cell adhesion processes and function as "integrin counter-receptors". We propose in this review grouping these transmembrane proteins, which include endoglin, cadherin-5, cadherin-6, cadherin-17, ADAM15, and L1CAM, under the newly coined acronym RGD-ICRs (RGD-containing Integrin Counter-Receptors). We present and discuss the structure of RGD-ICRs, their RGD-based interactions with integrins, the specific signaling pathways triggered in different cell types, as well as their pathophysiological involvement. It can be postulated that RGD-ICRs constitute an emerging group of non-canonical RGD-based integrin counter-receptors. In spite of being encoded by different and independent genes and involved in different pathophysiological processes, all of them appear to have undergone a strong evolutionary convergence in order to acquire the same functional capacity to bind integrins via the RGD motif. Importantly, these RGD-ICRs are also emerging as novel biomarkers and therapeutic targets, with promising clinical potential in a wide array of pathologies.

Triple-negative breast cancer (TNBC) is a particularly aggressive and therapeutically challenging subtype of breast cancer, defined by the lack of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression. This absence of actionable molecular targets contributes to its resistance to conventional treatments. This review provides an overview of the mechanistic functions, interrelated processes, and therapeutic implications of several programmed cell death (PCD) pathways-including apoptosis, pyroptosis, necroptosis, autophagy, and ferroptosis-in the context of TNBC pathogenesis and treatment. A conceptual framework is proposed for leveraging these interconnected cell death pathways as a basis for novel targeted interventions. Given the complex interplay among various PCD forms characterized by shared features such as inflammation, mitochondrial dysfunction, and overlapping molecular mediators, this integrated network offers promising opportunities for combinatorial therapeutic strategies. Modulation of one cell death pathway may influence others, potentially amplifying therapeutic efficacy. Furthermore, these PCD pathways are highly relevant to immunotherapy outcomes, offering a foundation for synergistic treatment modalities. This review provides an in-depth analysis of the crosstalk between immune-based therapies and PCD, along with a comprehensive discussion of derived therapeutic approaches. However, tumor diversity, resistance mechanisms, and discrepancies between preclinical models and human physiology pose major challenges in applying these findings clinically. The overarching goal is to present innovative insights and strategies to enhance the clinical management of TNBC and ultimately improve patient outcomes.

Background: Bone remodeling requires a complex interplay between osteogenesis and angiogenesis, orchestrated by yet not fully understood intricate signaling pathways in osteoblasts and endothelial cells.

Methods: In the present study, co-cultures of primary human osteoblasts and human umbilical vein endothelial cells (HUVEC) were compared with osteoblast cultures treated with dexamethasone (Dex), vascular endothelial growth factor (VEGF), their combination, or VEGF in the presence of Notch inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT). Cellular behavior was analyzed at morphological, gene expression, and protein levels to identify key regulators in the interplay between osteoblasts and endothelial cells.

Results: Dex and VEGF additively increased alkaline phosphatase (ALP) in osteoblast-HUVEC co-cultures, but not in osteoblast cultures. Furthermore, Dex reduced the receptor activator of nuclear factor κB ligand/osteoprotegerin (RANKL/OPG) ratio in osteoblasts. This effect was reversed in the presence of VEGF, but only in co-culture, indicating a direct action of endothelial cells, rather than VEGF itself, in stimulating RANKL and reducing OPG in osteoblasts. In addition, Notch signaling, specifically NOTCH1 and DLL4, was induced in response to VEGF solely in co-cultures. The presence of Notch inhibitor DAPT suppressed VEGF-induced stimulation of ALP but not RANKL/OPG ratio.

Conclusions: Our findings provide novel evidence for the significant role of endothelial cells in bone remodeling, specifically in regulating ALP expression and activity of osteoblasts via the Notch signaling pathway and RANKL/OPG ratio independent of Notch. This study underscores the applicability and significance of multicellular tissue models for studying bone turnover processes in vitro, thereby reducing the reliance on animal testing.

Background: FET (FUS, EWSR1, and TAF15) fusion oncoproteins are characteristic for several sarcomas and leukemias, including myxoid liposarcoma and Ewing sarcoma. FET oncoproteins interact with the SWI/SNF chromatin remodeling complex subtypes cBAF, PBAF, and GBAF, but their impact on SWI/SNF compositions, interactions, and downstream epigenetic effects remains elusive.

Methods: We employ a comprehensive immunoprecipitation and quantitative mass spectrometry approach to determine the impact of FET oncoproteins on SWI/SNF composition and their interactomes. Validation of complex composition and interaction partners is performed by glycerol gradient sedimentation assays and co-immunofluorescence analysis. Furthermore, we determine the differential chromatin accessibility and gene regulation in FET sarcomas using assay for transposase-accessible chromatin sequencing and RNA sequencing, respectively.

Results: Our data show that FET sarcomas have distinct SWI/SNF complex compositions, with different subunit paralogs and subtype-specific components that utilize distinct sets of interaction partners, including specific transcription factors. We show that FET oncoproteins cause no major disruption of the SWI/SNF complex composition. Instead, FUS::DDIT3-bound SWI/SNF complexes in myxoid liposarcoma cells are enriched in PBAF and GBAF components as well as most interaction partners.

Conclusions: These data suggest that FET oncoproteins act together with fully assembled and functional SWI/SNF complexes and recruited interaction partners. Finally, our data reveal that the SWI/SNF compositions, interactomes, and epigenetic background contribute to the tumor type in FET sarcoma. Trial registration Clinical trial number: not applicable.

Background: Autophagy, a conserved intracellular degradation process, plays dual roles in cancer, promoting survival under stress or mediating cell death through deregulated autophagy. Atypical cadherin FAT1 functions as an oncogene or tumor suppressor in a context-dependent manner. Our previous work identifies the oncogenic role of FAT1 in glioblastoma. Deregulated autophagy has been documented in glioma. Here, we investigated the role of FAT1 in regulating autophagy and its implications for glioblastoma growth and progression.

Methods: CRISPR-Cas9 mediated FAT1 knockout was generated in glioblastoma (U87MG and LN229) and other cancers such as hepatocellular carcinoma (HepG2 and HUH7) and pancreatic adenocarcinoma (MIAPaca-2 and Panc-1) cells. The cell viability and growth under hypoxia ± serum deprivation were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation, and Annexin V-FITC assays. Autophagy markers were assessed by quantitative polymerase chain reaction (qPCR), Western blot, immunocytochemistry (ICC), and immunohistochemistry (IHC). Autophagosomes were visualized by transmission electron microscopy (TEM), and puncta formation was analyzed by transfecting the cells with pEGFP-LC3. Autophagy flux was evaluated by analyzing p62/SQSTM1 levels, and the GFP/RFP ratio using pMRX-IP-GFP-LC3-RFP-LC3ΔG. In vivo, FAT1-knockout U87MG xenografts in nude mice were analyzed for tumor growth and autophagy marker expression. Surgically resected glioblastoma tumors from our hospital and The Cancer Genome Atlas (TCGA) dataset were analyzed for autophagy marker expression and patient survival correlations.

Results: FAT1-knockout glioblastoma (U87MG and LN229) cells demonstrated reduced survival and colony numbers under normoxia and hypoxia with serum deprivation, facilitated by autophagy-dependent cell death. These cells exhibited upregulated autophagy markers, increased LC3 puncta, autophagosomes, and autophagy flux. FAT1-knockout glioblastoma cells showed decreased total and phospho-mTOR levels. FAT1-knockout xenografts showed reduced tumor progression with increased LC3II, Beclin1, and autophagosomes. Human glioblastoma tumors and TCGA glioblastoma data revealed an inverse expression correlation of FAT1 with LC3B/Beclin1, tumors with high-FAT1/low-LC3B expression were associated with poor patient survival. FAT1 also regulated autophagy in hepatocellular and pancreatic cancers.

Conclusion: Our findings indicate that FAT1 mediates pro-tumorigenic function by suppressing autophagic cell death in glioblastoma and other cancers. FAT1 may serve as a potential therapeutic adjuvant along with standard therapeutic regimens for treating cancers with high FAT1 expression having an oncogenic role.

Background: Triple-negative breast cancer (TNBC) is the most prevalent and fatal cancer affecting women worldwide. The SWI/SNF complexes exhibit the ability to selectively replace subunits, thereby enabling a wide range of epigenetic functions. As an accessory subunit of this complex, ARID1B is critically involved in modulating chromatin accessibility and transcriptional regulation. Nevertheless, its precise contribution to TNBC pathogenesis remains poorly understood.

Methods: ARID1B expression levels in TNBC were detected using immunofluorescence and real-time quantitative polymerase chain reaction (PCR). To investigate ARID1B's biological functions in TNBC, a series of in vitro assays were conducted, complemented by subcutaneous tumor xenograft models. Mass spectrometry analysis was employed to identify ARID1B-interacting proteins, while RNA-sequencing (RNA-seq) was performed to screen downstream target genes regulated by ARID1B. The transcriptional regulatory mechanism of ZNF382 mediated by ARID1B was further validated through dual-luciferase reporter assays and Chromatin immunoprecipitation (ChIP)-qPCR. To determine if ZNF382 knockdown could reverse the cellular effects of ARID1B, SMARCC2, and SMARCB1 inhibition, functional rescue experiments were conducted.

Results: We identified ARID1B as a notable E3 ubiquitin ligase gene associated with breast cancer prognosis, particularly serving as a risk prognostic factor in TNBC. Contrary to its previously reported function as an E3 ubiquitin ligase, we observed that ARID1B transcriptionally represses ZNF382 by forming a novel SWI/SNF complex with SMARCC2 and SMARCB1. This newly assembled complex promotes TNBC proliferation and migration, highlighting a previously unrecognized mechanism of ARID1B in cancer development.

Conclusions: This research enhances the understanding of the intricate roles played by SWI/SNF complex components in TNBC and bridges the gap between the structural specificity of SWI/SNF assembly and the progression of cancer. These findings could potentially unveil novel therapeutic targets for TNBC, thereby advancing the development of more efficacious treatment approaches for this highly aggressive malignancy.

Background: Processing bodies (P-bodies) are nonmembranous ribonucleoprotein (RNP) granules located in the cytosol that function as assembly hubs for RNA storage and degradation. Although there are reports indicating that certain P-body proteins are also present at the centrosome and participate in primary cilia development, how these P-body proteins localize to the centrosome remains unclear. In mammalian cells, coiled-coil alpha-helical rod protein 1 (CCHCR1) is localized to both the P-bodies and centrosomes, where it interacts with the P-body component enhancer of mRNA-decapping protein 4 (EDC4) as well as a range of centriolar satellite components, yet its cellular function remains poorly characterized.

Methods: Biotin identification (BioID) coupled with mass spectrometry, immunoprecipitation (IP), glutathione S-transferase (GST) pull-down, and acceptor bleaching fluorescence resonance energy transfer (AB-FRET) assay were used to explore and identify protein-protein interactions. Gene overexpression, RNA interference-based gene knockdown, CRISPR-Cas9-mediated gene knockout, and immunofluorescence (IF) were applied to elucidate the underlying molecular mechanism.

Results: We identified that CCHCR1 interacts with oral-facial-digital syndrome 1 protein (OFD1) via its C-terminal coiled-coil domain. The centrosomal localization of CCHCR1 is determined by OFD1 and pericentriolar materials 1 (PCM1). We also found that CCHCR1 recruits P-body proteins to the centrosome through interacting with EDC4 via its N-terminal coiled-coil domain. Depletion of either CCHCR1 or P-body components EDC4 and DEAD-Box Helicase 6 (DDX6) impairs ciliogenesis.

Conclusions: CCHCR1 acts as a linker that recruits P-body proteins to the centrosome and is essential for cilia development. The recruitment of P-body proteins to the centrosome via CCHCR1 is also one of the mechanisms by which PCM1 and OFD1 are involved in ciliogenesis.

Background: The intestine is one of the most sensitive organs to ionizing radiation (IR), and radiation-induced intestinal injury (RIII) impacts the quality of life of patients undergoing radiotherapy. There are limited early diagnostic biomarkers and specific medicines clinically approved for RIII. Therefore, we sought to identify new theranostic targets to prevent RIII and to facilitate the reestablishment of the intestinal epithelium. Circular RNAs (circRNAs) are widely appreciated as pervasive regulators of many diseases and multiple biological processes, while whether and how specific circRNAs are involved in radiation-induced intestinal injury remains largely unknown.

Methods: Differentially expressed circRNAs were analyzed and verified via RNA sequencing. The function of an intestine-specific circRNA (termed circDmbt1(3,4,5,6)) on cell proliferation, apoptosis, and DNA damage level after radiation was explored in vitro, and the underlying mechanism was further investigated. Ultimately, intestinal organoids and mice model were used to verify the role of circDmbt1(3,4,5,6) on radiation-induced intestinal injury.

Results: Primarily expressed in intestinal stem cells, CircDmbt1(3,4,5,6) was downregulated in mice intestines after 14 Gy abdominal radiation and showed timely relationship with intestinal injury level. CircDmbt1(3,4,5,6) promoted the proliferation and alleviated cell apoptosis and DNA damage level of intestinal epithelial cells and promoted organoids survival after radiation compared with control groups. In vivo experiments showed that compared with control groups, overexpression of circDmbt1(3,4,5,6) could increase intestinal length; enhance epithelial integrity and the percentage of proliferative cells, stem cells, paneth cells, and goblet cells; and promote intestinal adaption after radiation. Mechanistically, circDmbt1(3,4,5,6) protects intestines from IR via circDmbt1(3,4,5,6)/miR-125a-5p/STAT3.

Conclusions: CircDmbt1(3,4,5,6), a novel promising RIII bio-marker, responses rapidly at the early stage after 14 Gy abdominal irradiation, and exogenous expression of circDmbt1(3,4,5,6) could promote intestinal fitness in RIII. We reveal that the circDmbt1(3,4,5,6)/miR-125a-5p/STAT3 axis is important to the regeneration of the intestinal epithelium after radiation-induced damage, providing a potential diagnostic and therapeutic target for RIII.

Background: Patients with sepsis commonly endure severe renal dysfunction and damage, hastening to end-stage renal failure with high mortality, and effective treatment options are currently lacking. Growth differentiation factor 11 (GDF11), belonging to the transforming growth factor beta (TGF-β) superfamily, has shown therapeutic potential for numerous acute and chronic inflammatory conditions. Nevertheless, its function in sepsis-associated acute kidney injury (SAKI) remains unclear.

Purpose: This study sought to explore GDF11's role in SAKI and determine the signaling pathways it modulates.

Methods: Alterations in GDF11 expression in the kidneys of mice with SAKI were analyzed. The influence of GDF11 knockdown and recombinant GDF11 (rGDF11) supplementation on cecal ligation and puncture (CLP)-induced SAKI in mice was determined. RNA sequencing, Western blot, real-time quantitative polymerase chain reaction (RT-qPCR), and kit assays were performed to explore the underlying mechanisms.

Results: Tubular epithelial cells and macrophages in the kidneys of CLP-induced SAKI mice exhibited high levels of GDF11 expression. Moreover, gene silencing of GDF11 using adeno-associated virus (AAV) aggravated renal dysfunction, increased tubular damage, and augmented renal apoptosis in CLP-induced SAKI mice. In contrast, replenishment of rGDF11 significantly mitigated these adverse effects. Further studies indicated that GDF11 stimulated the nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated antioxidative pathways, primarily by inducing the expression of Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), which subsequently decreased excessive inflammation and coagulation. Additionally, these beneficial effects of GDF11 were largely diminished by AAV-mediated PGC-1α knockdown and depletion of Nrf2 in CLP-induced SAKI mice.

Conclusions: In summary, these findings indicate that GDF11 is a potential therapeutic approach for SAKI and highlight the crucial role of PGC-1α/Nrf2 signaling in GDF11-mediated renal protection during SAKI.

Background: Epitranscriptomic data indicate that aberrant tRNA modifications in malignant diseases can promote tumor growth by facilitating oncogene translation. NSUN2, a 5-methylcytosine (m5C) methyltransferase of tRNA, is elevated in an array of solid cancers, including triple-negative breast cancer (TNBC). However, it remains unclear how NSUN2 drives aggressive behavior and if NSUN2 could be an effective therapeutic target for TNBC.

Methods: Functional experiments, including RNA interference, lentivirus transduction, and in vivo xenograft models, were conducted to evaluate the role of NSUN2 in TNBC cell proliferation, metastasis, and chemoresistance. Ribosome sequencing (Ribo-seq), tRNA m5C bisulfite sequencing, and codon usage bias analysis were employed to explore the translational mechanisms underlying NSUN2-mediated tRNA modifications. Glycolysis assays and molecular docking were used to investigate metabolic reprogramming and protein interactions.

Results: NSUN2 was significantly upregulated in TNBC and correlated with poor patient prognosis. Mechanistically, NSUN2 mediates m5C modification of tRNA^Val-CAC, enhancing the codon-frequency-dependent translation of key glycolysis-related genes, including ALDH3A2, ALDH7A1, HK1, and PFKM. Depletion of NSUN2 disrupted tRNA^Val-CAC m5C modification, impairing the translation of these metabolic enzymes and suppressing glycolysis, which ultimately inhibited TNBC cell proliferation, migration, and invasion both in vitro and in vivo. Furthermore, NSUN2 overexpression conferred resistance to docetaxel, while its inhibition sensitized TNBC cells to docetaxel treatment. Clinically, elevated expression levels of NSUN2 and glycolysis-related genes were observed in docetaxel-resistant TNBC tissues, further supporting the role of NSUN2 in chemoresistance.

Conclusions: This study identifies NSUN2 as a critical regulator of TNBC progression through tRNA^Val-CAC m5C modification and codon-biased translation of glycolysis-related mRNAs. Our findings reveal a novel NSUN2-tRNA^Val-CAC axis that orchestrates metabolic reprogramming and translational control in TNBC, offering a promising prognostic biomarker and therapeutic target.