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Cell Death & Disease Jun 2024Tripartite motif 8 (TRIM8) is an E3 ligase that plays dual roles in various tumor types. The biological effects and underlying mechanism of TRIM8 in hepatocellular...
Tripartite motif 8 (TRIM8) is an E3 ligase that plays dual roles in various tumor types. The biological effects and underlying mechanism of TRIM8 in hepatocellular carcinoma (HCC) remain unknown. Hepatocyte nuclear factor 1α (HNF1α) is a key transcriptional factor that plays a significant role in regulating hepatocyte differentiation and liver function. The reduced expression of HNF1α is a critical event in the development of HCC, but the underlying mechanism for its degradation remains elusive. In this study, we discovered that the expression of TRIM8 was upregulated in HCC tissues, and was positively correlated with aggressive tumor behavior of HCC and shorter survival of HCC patients. Overexpression of TRIM8 promoted the proliferation, colony formation, invasion, and migration of HCC cells, while TRIM8 knockdown or knockout exerted the opposite effects. RNA sequencing revealed that TRIM8 knockout suppresses several cancer-related pathways, including Wnt/β-catenin and TGF-β signaling in HepG2 cells. TRIM8 directly interacts with HNF1α, promoting its degradation by catalyzing polyubiquitination on lysine 197 in HCC cells. Moreover, the cancer-promoting effects of TRIM8 in HCC were abolished by the HNF1α-K197R mutant in vitro and in vivo. These data demonstrated that TRIM8 plays an oncogenic role in HCC progression through mediating the ubiquitination of HNF1α and promoting its protein degradation, and suggests targeting TRIM8-HNF1α may provide a promising therapeutic strategy of HCC.
Topics: Humans; Liver Neoplasms; Carcinoma, Hepatocellular; Hepatocyte Nuclear Factor 1-alpha; Ubiquitination; Disease Progression; Animals; Male; Mice; Mice, Nude; Hep G2 Cells; Cell Proliferation; Female; Cell Movement; Middle Aged; Ubiquitin-Protein Ligases; Gene Expression Regulation, Neoplastic; Mice, Inbred BALB C
PubMed: 38879600
DOI: 10.1038/s41419-024-06819-y -
Cell Death & Disease Jun 2024Tamoxifen has been the mainstay therapy to treat early, locally advanced, and metastatic estrogen receptor-positive (ER + ) breast cancer, constituting around 75% of...
Tamoxifen has been the mainstay therapy to treat early, locally advanced, and metastatic estrogen receptor-positive (ER + ) breast cancer, constituting around 75% of all cases. However, the emergence of resistance is common, necessitating the identification of novel therapeutic targets. Here, we demonstrated that long-noncoding RNA LINC00152 confers tamoxifen resistance by blocking tamoxifen-induced ferroptosis, an iron-mediated cell death. Mechanistically, inhibiting LINC00152 reduces the mRNA stability of phosphodiesterase 4D (PDE4D), leading to activation of the cAMP/PKA/CREB axis and increased expression of the TRPC1 Ca channel. This causes cytosolic Ca overload and generation of reactive oxygen species (ROS) that is, on the one hand, accompanied by downregulation of FTH1, a member of the iron sequestration unit, thus increasing intracellular Fe levels; and on the other hand, inhibition of the peroxidase activity upon reduced GPX4 and xCT levels, in part by cAMP/CREB. These ultimately restore tamoxifen-dependent lipid peroxidation and ferroptotic cell death which are reversed upon chelating Ca or overexpressing GPX4 or xCT. Overexpressing PDE4D reverses LINC00152 inhibition-mediated tamoxifen sensitization by de-activating the cAMP/Ca/ferroptosis axis. Importantly, high LINC00152 expression is significantly correlated with high PDE4D/low ferroptosis and worse survival in multiple cohorts of tamoxifen- or tamoxifen-containing endocrine therapy-treated ER+ breast cancer patients. Overall, we identified LINC00152 inhibition as a novel mechanism of tamoxifen sensitization via restoring tamoxifen-dependent ferroptosis upon destabilizing PDE4D, increasing cAMP and Ca levels, thus leading to ROS generation and lipid peroxidation. Our findings reveal LINC00152 and its effectors as actionable therapeutic targets to improve clinical outcome in refractory ER+ breast cancer.
Topics: Humans; Tamoxifen; Breast Neoplasms; Ferroptosis; Female; RNA, Long Noncoding; Cyclic AMP; Calcium; Drug Resistance, Neoplasm; Cell Line, Tumor; Animals; Receptors, Estrogen; Mice; Reactive Oxygen Species; MCF-7 Cells
PubMed: 38879508
DOI: 10.1038/s41419-024-06814-3 -
Molecular Medicine (Cambridge, Mass.) Jun 2024Myocardial infarction (MI) leads to enhanced activity of cardiac fibroblasts (CFs) and abnormal deposition of extracellular matrix proteins, resulting in cardiac...
BACKGROUND
Myocardial infarction (MI) leads to enhanced activity of cardiac fibroblasts (CFs) and abnormal deposition of extracellular matrix proteins, resulting in cardiac fibrosis. Tartrate-resistant acid phosphatase 5 (ACP5) has been shown to promote cell proliferation and phenotypic transition. However, it remains unclear whether ACP5 is involved in the development of cardiac fibrosis after MI. The present study aimed to investigate the role of ACP5 in post-MI fibrosis and its potential underlying mechanisms.
METHODS
Clinical blood samples were collected to detect ACP5 concentration. Myocardial fibrosis was induced by ligation of the left anterior descending coronary artery. The ACP5 inhibitor, AubipyOMe, was administered by intraperitoneal injection. Cardiac function and morphological changes were observed on Day 28 after injury. Cardiac CFs from neonatal mice were extracted to elucidate the underlying mechanism in vitro. The expression of ACP5 was silenced by small interfering RNA (siRNA) and overexpressed by adeno-associated viruses to evaluate its effect on CF activation.
RESULTS
The expression of ACP5 was increased in patients with MI, mice with MI, and mice with Ang II-induced fibrosis in vitro. AubipyOMe inhibited cardiac fibrosis and improved cardiac function in mice after MI. ACP5 inhibition reduced cell proliferation, migration, and phenotypic changes in CFs in vitro, while adenovirus-mediated ACP5 overexpression had the opposite effect. Mechanistically, the classical profibrotic pathway of glycogen synthase kinase-3β (GSK3β)/β-catenin was changed with ACP5 modulation, which indicated that ACP5 had a positive regulatory effect. Furthermore, the inhibitory effect of ACP5 deficiency on the GSK3β/β-catenin pathway was counteracted by an ERK activator, which indicated that ACP5 regulated GSK3β activity through ERK-mediated phosphorylation, thereby affecting β-catenin degradation.
CONCLUSION
ACP5 may influence the proliferation, migration, and phenotypic transition of CFs, leading to the development of myocardial fibrosis after MI through modulating the ERK/GSK3β/β-catenin signaling pathway.
Topics: Animals; Fibrosis; Myocardial Infarction; Mice; Humans; Tartrate-Resistant Acid Phosphatase; Male; Cell Proliferation; Disease Models, Animal; Fibroblasts; Myocardium; Glycogen Synthase Kinase 3 beta; Mice, Inbred C57BL; Signal Transduction; Cell Movement
PubMed: 38879488
DOI: 10.1186/s10020-024-00856-1 -
Diagnostic Microbiology and Infectious... Jun 2024Brucellosis is a critical zoonotic disease impacting humans and animals globally, causing symptoms like fever and arthritis in humans and reproductive issues in animals....
Brucellosis is a critical zoonotic disease impacting humans and animals globally, causing symptoms like fever and arthritis in humans and reproductive issues in animals. The disease stems from the Brucella genus, adept at evading the immune system and proliferating within host cells. This study explores how Brucella abortus manipulates host cellular mechanisms to sustain infection, focusing on the interaction with murine macrophages over 24 h. Initial host defenses involve innate immune responses, while Brucella's survival strategies include evading lysosomal degradation and modulating host cell functions through various pathways. The research identified significant transcriptional changes in macrophages post-infection, highlighting pathways such as cytokine storm, pyroptosis signaling, Toll-like receptor pathways, and LXRs/RXRs signaling. The findings shed light on Brucella's complex mechanisms to undermine host defenses and underscore the need for further investigation into therapeutic targets to combat brucellosis.
PubMed: 38878343
DOI: 10.1016/j.diagmicrobio.2024.116401 -
Cell Reports Jun 2024Epitranscriptomics represents a further layer of gene expression regulation. Specifically, N6-methyladenosine (m6A) regulates RNA maturation, stability, degradation, and...
Epitranscriptomics represents a further layer of gene expression regulation. Specifically, N6-methyladenosine (m6A) regulates RNA maturation, stability, degradation, and translation. Regarding microRNAs (miRNAs), while it has been reported that m6A impacts their biogenesis, the functional effects on mature miRNAs remain unclear. Here, we show that m6A modification on specific miRNAs weakens their coupling to AGO2, impairs their function on target mRNAs, determines their delivery into extracellular vesicles (EVs), and provides functional information to receiving cells. Mechanistically, the intracellular functional impairment is caused by m6A-mediated inhibition of AGO2/miRNA interaction, the EV loading is favored by m6A-mediated recognition by the RNA-binding protein (RBP) hnRNPA2B1, and the EV-miRNA function in the receiving cell requires their FTO-mediated demethylation. Consequently, cells express specific miRNAs that do not impact endogenous transcripts but provide regulatory information for cell-to-cell communication. This highlights that a further level of complexity should be considered when relating cellular dynamics to specific miRNAs.
PubMed: 38878288
DOI: 10.1016/j.celrep.2024.114369 -
Cellular & Molecular Biology Letters Jun 2024CircR-loop, a recently unearthed regulatory mechanism situated at the crossroads of circular RNA and DNA interactions, constitute a subset of R-loop. This circR-loop... (Review)
Review
CircR-loop, a recently unearthed regulatory mechanism situated at the crossroads of circular RNA and DNA interactions, constitute a subset of R-loop. This circR-loop have emerged as a crucial player in pivotal regulatory functions within both animal and plant systems. The journey into the realm of circR-loop commenced with their discovery within the human mitochondrial genome, where they serve as critical directors of mitochondrial DNA replication. In the plant kingdom, circR-loop wield influence over processes such as alternative splicing and centromere organization, impacting the intricacies of floral development and genome stability, respectively. Their significance extends to the animal domain, where circR-loop has captured attention for their roles in cancer-related phenomena, exerting control over transcription, chromatin architecture, and orchestrating responses to DNA damage. Moreover, their involvement in nuclear export anomalies further underscores their prominence in cellular regulation. This article summarizes the important regulatory mechanisms and physiological roles of circR-loop in plants and animals, and offers a comprehensive exploration of the methodologies employed for the identification, characterization, and functional analysis of circR-loop, underscoring the pressing need for innovative approaches that can effectively distinguish them from their linear RNA counterparts while elucidating their precise functions. Lastly, the article sheds light on the challenges and opportunities that lie ahead in the field of circR-loop research, emphasizing the vital importance of continued investigations to uncover their regulatory roles and potential applications in the realm of biology. In summary, circR-loop represents a captivating and novel regulatory mechanism with broad-reaching implications spanning the realms of genetics, epigenetics, and disease biology. Their exploration opens new avenues for comprehending gene regulation and holds significant promise for future therapeutic interventions.
Topics: Genomic Instability; Humans; Animals; RNA, Circular; DNA; R-Loop Structures; RNA; DNA Replication
PubMed: 38877420
DOI: 10.1186/s11658-024-00606-5 -
Cancer Letters Jun 20245-Methylcytosine (m5C) methylation is a significant post-transcriptional modification that play a crucial role in the development and progression of numerous cancers....
5-Methylcytosine (m5C) methylation is a significant post-transcriptional modification that play a crucial role in the development and progression of numerous cancers. Whereas the functions and molecular mechanisms underlying m5C methylation in gliomas remain unclear. This study dedicated to explore changes of m5C levels and the clinical significance of the m5C writer NSUN4 in gliomas. We found that high m5C levels were negatively related to prognosis of patients with glioma. Moreover, gain- and loss-of-function experiments revealed the role of NSUN4 in enhancing m5C modification of mRNA to promote the malignant progression of glioma. Mechanistically speaking, NSUN4-mediated m5C alterations regulated ALYREF binding to CDC42 mRNA, thereby impacting the mRNA stability of CDC42. We also demonstrated that CDC42 promoted glioma proliferation, migration, and invasion by activating the PI3K-AKT signaling pathway. Additionally, rescue experiments proved that CDC42overexpression weaken the inhibitory effect of NSUN4 knockdown on the malignant progression of gliomas in vitro and in vivo. Our findings elucidate that NSUN4-mediated high m5C levels promote ALYREF binding to CDC42 mRNA and regulate its stability, thereby driving the malignant progression of glioma. This provides theoretical support for targeted the treatment of gliomas.
PubMed: 38876383
DOI: 10.1016/j.canlet.2024.217059 -
The Journal of Biological Chemistry Jun 2024Chemotherapeutic agents for treating colorectal cancer primarily induce apoptosis in tumor cells. The ubiquitin-proteasome system (UPS) is critical for apoptosis...
Chemotherapeutic agents for treating colorectal cancer primarily induce apoptosis in tumor cells. The ubiquitin-proteasome system (UPS) is critical for apoptosis regulation. Deubiquitinating enzymes (DUBs) remove ubiquitin from substrates to reverse ubiquitination. Although over 100 DUB members have been discovered, the biological functions of only a small proportion of DUBs have been characterized. Here, we aimed to systematically identify the DUBs that contribute to the development of colorectal cancer. Among the DUBs, ubiquitin-specific protease 36 (USP36), is upregulated in colorectal cancer. We showed that the knockdown of USP36 induces intrinsic and extrinsic apoptosis. Through gene silencing and coimmunoprecipitation techniques, we identified survivin and cIAP1 as USP36 targets. Mechanistically, USP36 binds and removes lysine-11 (K11)-linked ubiquitin chains from cIAP1 and lysine-48 (K48)-linked ubiquitin chains from survivin to abolish protein degradation. Overexpression of USP36 disrupts the formation of the XIAP-Smac complex and promotes RIPK1 ubiquitination, validating USP36 as an inhibitor to intrinsic and extrinsic apoptosis through deubiquitinating survivin and cIAP1. Therefore, our results suggest that USP36 is involved in colorectal cancer progression and is a potential therapeutic target.
PubMed: 38876304
DOI: 10.1016/j.jbc.2024.107463 -
Journal of Experimental & Clinical... Jun 2024Understanding the mechanisms that mediate the interaction between tumor and immune cells may provide therapeutic benefit to patients with cancer. The N6-methyladenosine...
BACKGROUND
Understanding the mechanisms that mediate the interaction between tumor and immune cells may provide therapeutic benefit to patients with cancer. The N6-methyladenosine (m6A) demethylase, ALKBH5 (alkB homolog 5), is overexpressed in non-small cell lung cancer. However, its role in the tumor microenvironment is unknown.
METHODS
Datasets and tissue samples were used to determine the relationship between ALKBH5 expression and immunotherapy efficacy. Bioinformatic analysis, colorimetric assay to determine m6A RNA methylation, dual luciferase reporter assay, RNA/m6A-modified RNA immunoprecipitation, RNA stability assay, and RNA sequencing were used to investigate the regulatory mechanism of ALKBH5 in non-small cell lung cancer. In vitro and in vivo assays were performed to determine the contribution of ALKBH5 to the development of non-small cell lung cancer.
RESULTS
ALKBH5 was upregulated in primary non-small cell lung cancer tissues. ALKBH5 was positively correlated with programmed death-ligand 1 expression and macrophage infiltration and was associated with immunotherapy response. JAK2 was identified as a target of ALKBH5-mediated m6A modification, which activates the JAK2/p-STAT3 pathway to promote non-small cell lung cancer progression. ALKBH5 was found to recruit programmed death-ligand 1-positive tumor-associated macrophages and promote M2 macrophage polarization by inducing the secretion of CCL2 and CXCL10. ALKBH5 and tumor-associated macrophage-secreted IL-6 showed a synergistic effect to activate the JAK2/p-STAT3 pathway in cancer cells.
CONCLUSIONS
ALKBH5 promotes non-small cell lung cancer progression by regulating cancer and tumor-associated macrophage behavior through the JAK2/p-STAT3 pathway and the expression of CCL2 and CXCL10, respectively. These findings suggest that targeting ALKBH5 is a promising strategy of enhancing the anti-tumor immune response in patients with NSCLC and that identifying ALKBH5 status could facilitate prediction of clinical response to anti-PD-L1 immunotherapy.
Topics: Carcinoma, Non-Small-Cell Lung; Humans; AlkB Homolog 5, RNA Demethylase; Lung Neoplasms; Mice; Animals; Macrophages; Disease Progression; B7-H1 Antigen; Female; Cell Line, Tumor; Tumor Microenvironment; Janus Kinase 2; Male; Mice, Nude
PubMed: 38872221
DOI: 10.1186/s13046-024-03073-0 -
Experimental & Molecular Medicine Jun 2024Circular RNAs (circRNAs) are covalently closed single-stranded RNAs without a 5' cap structure and a 3' poly(A) tail typically present in linear mRNAs of eukaryotic... (Review)
Review
Circular RNAs (circRNAs) are covalently closed single-stranded RNAs without a 5' cap structure and a 3' poly(A) tail typically present in linear mRNAs of eukaryotic cells. CircRNAs are predominantly generated through a back-splicing process within the nucleus. CircRNAs have long been considered non-coding RNAs seemingly devoid of protein-coding potential. However, many recent studies have challenged this idea and have provided substantial evidence that a subset of circRNAs can associate with polysomes and indeed be translated. Therefore, in this review, we primarily highlight the 5' cap-independent internal initiation of translation that occurs on circular RNAs. Several molecular features of circRNAs, including the internal ribosome entry site, N-methyladenosine modification, and the exon junction complex deposited around the back-splicing junction after back-splicing event, play pivotal roles in their efficient internal translation. We also propose a possible relationship between the translatability of circRNAs and their stability, with a focus on nonsense-mediated mRNA decay and nonstop decay, both of which are well-characterized mRNA surveillance mechanisms. An in-depth understanding of circRNA translation will reshape and expand our current knowledge of proteomics.
PubMed: 38871818
DOI: 10.1038/s12276-024-01220-3