Cellular & Molecular Biology Letters最新文献

Background: Lung cancer, primarily lung adenocarcinoma (LUAD), is the leading cause of cancer-related deaths worldwide. Despite extensive research, the mechanisms behind LUAD progression remain inadequately understood, underscoring the need for new biomarkers and therapeutic targets. Ribosomal proteins, traditionally associated with protein synthesis, are gaining recognition for their roles in tumorigenesis, though many functions remain unexplored.

Methods: This study utilized single-cell transcriptomic data and bioinformatics analyses to identify potential LUAD biomarkers. Selected biomarkers were validated using quantitative PCR (qPCR) and immunofluorescence on clinical samples. Functional roles were assessed through in vivo and in vitro assays, including migration, invasion, and proliferation studies. Mechanistic insights were gained via mRNA stability assays, RNA immunoprecipitation, fluorescence in situ hybridization, and dual luciferase reporter assays.

Results: RPL7A is a significant prognostic marker with elevated expression in metastatic LUAD tissues. Clinical validation shows that high RPL7A expression correlates with LUAD occurrence and poor overall survival (OS) (hazard ratio > 1). RPL7A knockdown inhibits LUAD cell migration, invasion, and proliferation, underscoring its key role in tumor progression. Mechanistically, RPL7A impacts lipid metabolism and the AKT pathway. Crucially, RPL7A regulates circRANBP17, a circRNA linked to LUAD metastasis and lipid metabolism. This interaction forms a complex with UPF1 to destabilize SIRT6 mRNA, a critical factor in lipogenesis. The resulting downregulation of SIRT6 highlights how RPL7A and circRANBP17 contribute to altered lipid metabolism and tumor progression in LUAD.

Conclusions: Our findings demonstrate that RPL7A promotes LUAD progression through circRANBP17-UPF1-mediated SIRT6 degradation, positioning RPL7A as a potential therapeutic target in LUAD.

Background: Hypoxia significantly influences the development of pulmonary hypertension (PH). However, the role of transfer RNA-derived small RNAs (tsRNAs) produced by nuclease cleavage on PH, particularly their impact on the proliferation of pulmonary artery endothelial cells (PAECs), remains unclear.

Methods: To detect tsRNA expression, panoramic RNA display by overcoming RNA modification aborted sequencing (PANDORA-seq) sequencing analysis and quantitative polymerase chain reaction (qPCR) were employed. The formation of R-loops between tsRNA and genomic DNA was confirmed through chromatin immunoprecipitation followed by polymerase chain reaction (ChIP-PCR) and Dot-blot analyses. Mouse PAECs and lung tissue were manipulated to either overexpress or inhibit tsRNA-3040b, followed by assessments of cell proliferation, RT-qPCR, and enzyme activity assays on three key glycolytic rate-limiting enzymes. Molecular docking, immunofluorescence and endogenous coprecipitation were used to demonstrate the colocalization of Trim35 and Wnt3a.

Results: The expression of tsRNA-Asp-GTC-3040b (termed tsRNA-3040b) was significantly increased in the lung tissue of a hypoxia-induced PH mouse model. By integrating database prediction with RNA sequencing, Trim35 was identified as a downstream target of tsRNA-3040b. ChIP-PCR and Dot-blot analyses using S9.6 indicated that tsRNA-3040b promoted R-loops in the genomic DNA of Trim35, thus inhibiting its transcription. Further investigation revealed that the Trim35 affected glucose metabolism levels through ubiquitinated substrate Wnt3a. Ultimately, it was elucidated that the tsRNA-3040b-Trim35-Wnt3a-glucose metabolism signaling pathway exacerbated the progression of PH.

Conclusions: This study highlights the role of tsRNA-3040b in promoting PH by influencing glucose metabolism processes. These results offer a new approach to treating PH and suggest that tsRNA-3040b could serve as a potential target for diagnosing PH and related conditions.

Colorectal cancer (CRC) ranks among the most common malignant cancers of the digestive system, and its initiation and progression are closely related to both genetic and epigenetic mechanisms. Three major forms of modifications, viz. DNA methylation, RNA m6A methylation, and histone methylation, play important roles in regulating gene expression at various stages of transcription and translation. These methylation processes are dynamic and reversible, relying on the functions of methyltransferases, demethylases, and methylation-binding proteins. Extensive studies have shown that DNA, RNA m6A, and histone methylation significantly impact multiple pathological and physiological processes in CRC, including carcinogenesis, recurrence, metastasis, resistance to both radiotherapy and chemotherapy, as well as immune regulation. Advances in high-throughput sequencing and laboratory techniques have facilitated the identification of methylation regulation enzymes with aberrant expression at the DNA, RNA, and protein levels, revealing their clinical potential for early diagnosis and treatment of CRC. The upstream regulatory mechanisms controlling these methylation regulation enzymes are crucial for understanding alterations in methylation patterns. Current evidence identifies several key mechanisms, including posttranslational modifications, epigenetic regulation, and genetic alterations, which collectively influence the expression, activity, and stability of methyltransferases, demethylases, and binding proteins. These mechanisms thereby modulate the dynamic methylation landscape across various biological contexts. Furthermore, the complex crosstalk among DNA, RNA m6A, and histone methylation is increasingly being elucidated, highlighting a need for further investigation in CRC. In this review, we systematically summarize the molecular mechanisms, clinical applications, and crosstalk involving DNA methylation, RNA m6A methylation, and histone methylation, along with their related enzymes in the development of CRC. This review aims to provide new insights and directions that underscore the significant role of epigenetic methylation modifications and their associated enzymes in CRC.

Background: Ovarian aging-induced decline in oocyte quality has been a main issue in women of advanced maternal age. However, the potential mechanism remains elusive, and there are no effective strategies to ameliorate aged oocyte quality. The lipid metabolism of oocytes has drawn great attention, but the intrinsic regulation of oocyte quality by metabolites, metabolic enzymes, and intracellular mediators is less well-characterized.

Methods: Targeted lipidomics was employed to detect the neutral lipids in oocytes during maturation. We used 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY 493/503) and Filipin to stain cholesteryl ester and free cholesterol, respectively. The Cholesterol/Cholesteryl Ester Quantification Assay kit was used further to quantify cholesterol-related metabolites. Western blotting was performed to evaluate acyl-coenzyme A: cholesterol acyltransferase 1/2 (ACAT1/2) expression. Immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR) were conducted to validate the knockdown efficiency of ACAT1. Avasimibe treatment and ACAT1 small interfering RNA (siRNA) microinjection were performed to investigate the effect of impaired cholesterol-cholesteryl ester metabolism on oocyte quality. Single-oocyte RNA sequencing was conducted to explore the mechanism. Mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) production, reactive oxygen species (ROS), and mitochondrial autophagosomes were detected to evaluate mitochondrial function and mitophagy.

Results: There is a profound increase in the conversion of cholesterol to cholesteryl ester in oocytes during maturation, which depends on ACAT1. Conversely, disturbing the homeostasis of cholesterol-cholesteryl ester metabolism by manipulating ACAT1 impairs oocyte quality, primarily manifested as decreased polar body extrusion (PBE), increased meiotic defects, and abnormal early embryonic development. Mechanistically, the impaired conversion of cholesterol to cholesteryl ester reduces oocyte mitophagy, leading to mitochondrial dysfunction, including reduced MMP and ATP production, and excessive accumulation of ROS. Notably, we also reveal that this metabolic homeostasis is impaired in aged oocytes, accompanied by decreased ACAT1 levels. Moreover, cholesteryl ester supplementation via cholesterol conjugated to methyl-β-cyclodextrin (CCM) can effectively ameliorate aged oocyte quality by enhancing mitophagy.

Conclusions: This study reveals the mechanism by which cholesterol-cholesteryl ester metabolism regulates oocyte quality and thus participates in the process of oocyte aging by influencing mitophagy and mitochondrial function.