ABSTRACT
Accumulating evidence has confirmed the links between transfer RNA (tRNA) modifications and tumor progression. The present study is the first to explore the role of tRNA methyltransferase 5 (TRMT5), which catalyzes the m1G37 modification of mitochondrial tRNAs in hepatocellular carcinoma (HCC) progression. Here, based on bioinformatics and clinical analyses, we identified that TRMT5 expression was upregulated in HCC, which correlated with poor prognosis. Silencing TRMT5 attenuated HCC proliferation and metastasis both in vivo and in vitro, which may be partially explained by declined extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Mechanistically, we discovered that knockdown of TRMT5 inactivated the hypoxia-inducible factor-1 (HIF-1) signaling pathway by preventing HIF-1α stability through the enhancement of cellular oxygen content. Moreover, our data indicated that inhibition of TRMT5 sensitized HCC to doxorubicin by adjusting HIF-1α. In conclusion, our study revealed that targeting TRMT5 could inhibit HCC progression and increase the susceptibility of tumor cells to chemotherapy drugs. Thus, TRMT5 might be a carcinogenesis candidate gene that could serve as a potential target for HCC therapy.
Subject(s)
Humans , Carcinoma, Hepatocellular/pathology , Cell Hypoxia , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Liver Neoplasms/pathology , Signal Transduction/genetics , tRNA Methyltransferases/metabolismABSTRACT
Objective:To explore the effect of transfer RNA-derived small molecule fragment 770(tRF-770) on proliferation of breast cancer cells through regulating cytoskeletal-associated protein 2 (CKAP2).Methods:Chromosome localization of tRF-770 was identified using the MINTbase database v2.0 sequence alignment with mature tRNA in the genome. TA cloning assay was used to identify tRF-770; TargetScan and miRBase database were used to analyze and predict the target genes of tRF-770. The expression of CKAP2 in breast cancer was analyzed by using the data from The Cancer Genome Atlas (TCGA) database. Breast cancer cell lines MDB-MA-231 and MCF7 were selected and divided into three groups: blank control group (without any treatment), tRF-770 overexpression group (transfected with tRF-770 overexpression sequence) and negative control group (transfected with negative control sequence). In addition, tRF-770 overexpression+CKAP2-HA group was established (co-transfected with tRF-770 overexpression sequence and CKAP2 overexpression sequence). Real-time quantitative fluorescence polymerase chain reaction (qRT-PCR) was used to detect the relative expression of tRF-770 in breast cancer cells. CCK-8 assay was used to detect the proliferation of breast cancer cells and perform rescue experiment. Dual luciferase reporter gene assay was used to verify the target genes of tRF-770. The protein expression of CKAP2-ERK2 signaling pathway was detected by Western blotting.Results:tRF-770 completely matched 5' UTR spliced and modified by 9 kinds of tRNA. TA clone sequencing verification results showed that the product size and bases were consistent with the expected tRF-770 sequences. CKAP2 was highly expressed in breast cancer tissues based on analysis of the data from TCGA database ( t = 7.21, P < 0.05). qRT-PCR showed that the relative expressions of tRF-770 in MDA-MB-231 cells of blank control group, negative control group and tRF-770 overexpression group were 1.00±0.00, 2.42±0.11 and 3.75±0.01, respectively, and the difference was statistically significant ( F = 1 395.00, P < 0.001). The relative expressions of tRF-770 in MCF7 cells of 3 groups were 1.00±0.00, 2.45±0.21 and 3.26±0.16, respectively, and the difference was statistically significant ( F = 169.30, P < 0.001). Compared with blank control group and negative control group, the relative expression of tRF-770 in tRF-770 overexpression group in 2 cell lines was increased (all P < 0.05). Dual luciferase reporter assay showed that tRF-770 bound to CKAP2 mRNA 3'UTR. CCK-8 assay showed that in MDA-MB-231 and MCF7 cells, the cell proliferation ability of tRF-770 overexpression group on the 3rd and 4th day was lower than that of blank control group and negative control group (both P < 0.05); there were significant differences in cell proliferation ability between the negative control group and tRF-770 overexpression group on the 3rd and 4th day (all P < 0.05). CCK-8 assay showed that in 2 breast cancer cell lines, the cell proliferation ability of tRF-770 overexpression+ CKAP2-HA group was higher than that of tRF-770 overexpression group since the second day after transfection (all P < 0.05). Western blotting showed that the expressions of CKAP2, p-ERK2 and PCNA proteins in tRF-770 overexpression group were decreased compared with the negative control group (all P < 0.05). The change of ERK2 protein expression was small in MDA-MB-231 cells, but the expression of protein in tRF-770 overexpression group in MCF7 cells was decreased. Conclusions:tRF-770 may inhibit the proliferation of breast cancer cells through CKAP2-ERK2 signaling pathway.
ABSTRACT
Transfer RNA (tRNA)-derived small non-coding RNAs (tsRNAs) are generated through specific endonucleolytic cleavage of mature or precursor tRNA at different sites and exist widely in prokaryotic and eukaryotic transcriptome, and are a new class of gene expression regulators with a variety of biological functions. tsRNAs participate in some physiological and pathological processes, including stress response, protein translation, ribosomal biosynthesis and regulating immunity. Dysregulation of tsRNAs is closely related with the occurrence and development of many human diseases. This article reviewed the advance in study on tsRNAs in gastrointestinal tumors.
ABSTRACT
Skeletal muscle is an important tissue of human and livestock. The study of the muscle development is of great significance for treating muscle diseases and improving livestock meat quality. The process of muscle development is controlled by several myogenic transcription factors and signaling pathways. In addition, recent findings established that several noncoding RNAs play a critical role in the regulation of muscle development such as long non-coding RNA (lncRNA), microRNA (miRNA) and circu- lar RNA (circRNA), etc. The detailed mechanism of muscle development is not well understood. Transfer RNAs (tRNAs) are fundamental components in the translation machinery as an adaptor molecule, and tRNA pool could be differentially exploited to modulate expression of mRNAs. In addition, tRNA can be cleaved into tRNA-derived fragments (tRFs) by a variety of ribonucleases (RNases) upon various stress conditions. Unlike the post-transcriptional regulation of lncRNA and miRNA on muscle development, tRNA has been implicated in various aspects of muscle development. Mitochondria play a central role in a plethora of processes related to the maintenance of muscle cellular homeostasis and genomic integrity. Mitochondrial tRNA(mt-tRNA) gene mutations lead to multiple myopathy because human mitochondrial genome is extremely small. The regulation of tRF is similar to miRNAs in regards to the related physiological processes, but are more conservative than miRNA. It is generally believed that tRF has strong tissue specificity, disease specificity and temporal specificity. Some skeletal muscle-specific tRFs could act posttranscriptionally via RNAi or targeting related genes. However, the tRF-sequencing analysis and functional mechanism of tRF are rarely studied in skeletal muscles. The myopathy caused by mitochondrial tRNA gene mutations are particularly complex, which are one of the challenges to diagnose, treat, or prevent diseases. Compared with other noncoding RNAs, the structural complexity of tRF also brings great challenges to data mining and analysis. In this review, we summarize the formation and function of tRNA and tRF especially in muscle development, which will deepen our understandings of related myopathy, and provide new ideas and directions for the investigation of skeletal muscle.
ABSTRACT
OBJECTIVE@#Bushen Tiansui formula (BSTSF), a traditional Chinese medicine prescription, has been widely used to treat Alzheimer's disease (AD). However, the mechanisms underlying its effects remain largely unknown. In this study, a rat AD model was used to study the effects of BSTSF on cognitive performance and expression of transfer RNA-derived small RNAs (tsRNAs) in the hippocampus, to determine whether treatment of AD with BSTSF could regulate the expression of tsRNAs, a novel small non-coding RNA.@*METHODS@#To generate a validated AD model, oligomeric amyloid-β@*RESULTS@#The learning and memory deficits of Aβ@*CONCLUSION@#This study identified a previously uncharacterized mechanism underlying the effects of BSTSF in alleviating the learning and memory deficits in Aβ
ABSTRACT
Objective: Immunosuppressive therapy for interstitial lung disease (ILD) is often necessary, but the standard regimen for antisynthetase-associated ILD has not been established.Patient: An 80-year-old man was hospitalized for severely progressive dyspnea. Bilateral interstitial shadows occurred 1 month before the event. Serological findings showed that he had antisynthetase-associated ILD, as identified by strong positivity for anti-aminoacyl-transfer RNA synthetase (ARS) antibody, despite no evidence of myositis. He was treated transiently with noninvasive positive pressure ventilation and steroid-pulse therapy followed by 60 mg/day of oral prednisolone. However, his diabetes mellitus was aggravated by corticosteroid therapy; thus, a combination of low-dose steroid and mizoribine (MZB), which has a low risk of aggravating glucose intolerance, was used.Results: The patient’s clinical symptoms and daily life activities have been well persevered as an outpatient and well maintained with 200 mg of MZB and 10 mg of prednisolone for several months without obvious clinical recurrence and without any remarkable steroid- and MZB-related side effects.Conclusion: The use of MZB appeared to suppress the pathophysiology of anti-ARS antibody-associated ILD.
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Total tRNA was isolated, purified and quantitated from earthworm, cockroach, fresh water mussel and rat liver. The total tRNA content of invertebrates was found to be much lower than that of rat liver. When checked for aminoacylation capacity with homologous and heterologous enzymes and algal protein hydrolysate, the tRNA preparation from rat liver and fresh water mussel, a mollusc, were found to be active. On the other hand, the tRNAs from earthworm, an annelid, and cockroach, an arthropod, were completely inactive with the homologous enzymes but showed partial activity with heterologous enzymes. Similar results were obtained with individual amino acids also. The low activity or inactivity of earthworm and cockroach tRNAs appears to be due to certain endogenous aminoacylation inhibitors.
ABSTRACT
In vitro methyiation of Escherichia coli transfer ribonucleic acid by cell free extracts of Mycobacterium smegmatis leads exclusively to the formation of 1-methyl adenine [Vani, B. R., Ramakrishnan, T., Taya, Y., Noguchi, S., Yamaiuzumi, Z. and Nishimura, S. (1978) J. Bact., 137,1085]. We have studied the effect of this modification on aminoacylation of Escherichia coli tRNA by mycobacterial enzymes. Aminoacylation with total algal protein hydrolysate as well as several individual aminoacids like methionine, valine, tyrosine, aspartic acid and lysine were monitored. In all the cases methyiation had a positive effect on the extent of aminoacylation by mycobacterial enzymes. Decreased aminoacylation in vitro was observed when hypomethylated transfer RNA from ethionine treated cells was used as the substrate for aminoacylation.