tRNA-derived small RNAs (tsRNAs)—small RNA fragments derived from transfer ribonucleic acid (tRNA)—fall into the category of small non-coding RNAs (sncRNAs). They can be categorized into two major types: tRNA-derived fragments (tRFs) and tRNA-derived stress-induced small RNAs (tiRNAs). With the rapid advancement in high-throughput sequencing technologies and bioinformatics, tsRNAs have been involved in a variety of biological processes, including gene expression, signal transduction, and epigenetic inheritance, while also playing a significant role in tumor progression. The efficacy of radiotherapy is primarily affected by radiation-induced damage to normal tissues and the resistance of tumor cells to radiotherapy. It has been found that tsRNAs plays a significant role in radiation-induced cellular damage, as well as the modulation of radiation sensitivity and resistance. This highlights their potential as promising therapeutic targets in radiotherapy for tumors. This study reviews the origins, classification, biological functions of tRFs, as well as the advances in research on their role in tumor formation and progression and their applications in radiotherapy for tumors. This study aims to explore the research value of tRFs and their potential for application in radiotherapy for tumors.

tRNA-derived small RNAs (tsRNAs)—small RNA fragments derived from transfer ribonucleic acid (tRNA)—fall into the category of small non-coding RNAs (sncRNAs). They can be categorized into two major types: tRNA-derived fragments (tRFs) and tRNA-derived stress-induced small RNAs (tiRNAs). With the rapid advancement in high-throughput sequencing technologies and bioinformatics, tsRNAs have been involved in a variety of biological processes, including gene expression, signal transduction, and epigenetic inheritance, while also playing a significant role in tumor progression. The efficacy of radiotherapy is primarily affected by radiation-induced damage to normal tissues and the resistance of tumor cells to radiotherapy. It has been found that tsRNAs plays a significant role in radiation-induced cellular damage, as well as the modulation of radiation sensitivity and resistance. This highlights their potential as promising therapeutic targets in radiotherapy for tumors. This study reviews the origins, classification, biological functions of tRFs, as well as the advances in research on their role in tumor formation and progression and their applications in radiotherapy for tumors. This study aims to explore the research value of tRFs and their potential for application in radiotherapy for tumors.

Background::Radiation (IR)-induced DNA damage triggers cell cycle arrest and has a suppressive effect on the tumor microenvironment (TME). Wee1, a cell cycle regulator, can eliminate G2/M arrest by phosphorylating cyclin-dependent kinase 1 (CDK1). Meanwhile, programed death-1/programed death ligand-1 (PD-1/PDL-1) blockade is closely related to TME. This study aims to investigate the effects and mechanisms of Wee1 inhibitor AZD1775 and anti-PD-1 antibody (anti-PD-1 Ab) on radiosensitization of hepatoma.Methods::The anti-tumor activity of AZD1775 and IR was determined by 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) assay on human and mouse hepatoma cells HepG2, Hepa1-6, and H22. The anti-hepatoma mechanism of AZD1775 and IR revealed by flow cytometry and Western blot in vitro. A hepatoma subcutaneous xenograft mice model was constructed on Balb/c mice, which were divided into control group, IR group, AZD1775 group, IR + AZD1775 group, IR + anti-PD-1 Ab group, and the IR + AZD1775 + anti-PD-1 Ab group. Cytotoxic CD8 + T cells in TME were analyzed by flow cytometry. Results::Combining IR with AZD1775 synergistically reduced the viability of hepatoma cells in vitro. AZD1775 exhibited antitumor effects by decreasing CDK1 phosphorylation to reverse the IR-induced G2/M arrest and increasing IR-induced DNA damage. AZD1775 treatment also reduced the proportion of PD-1 +/CD8 + T cells in the spleen of hepatoma subcutaneous xenograft mice. Further studies revealed that AZD1775 and anti-PD-1 Ab could enhance the radiosensitivity of hepatoma by enhancing the levels of interferon γ (IFNγ) + or Ki67 + CD8 T cells and decreasing the levels of CD8 + Tregs cells in the tumor and spleen of the hepatoma mice model, indicating that the improvement of TME was manifested by increasing the cytotoxic factor IFNγ expression, enhancing CD8 + T cells proliferation, and weakening CD8 + T cells depletion. Conclusions::This work suggests that AZD1775 and anti-PD-1 Ab synergistically sensitize hepatoma to radiotherapy by enhancing IR-induced DNA damage and improving cytotoxic CD8 + T cells in TME.

Objective: To investigate GATA3 expression and the regulatory mechanism of m6A modification in the re- sponse of alveolar epithelial cells to radiation, and to provide a new therapeutic target for radiation-induced lung injury based on its pathogenesis. Methods: Human lung epithelial cell line (A549) and mouse lung epithelial cell line (MLE-12) were exposed to X-ray irradiation with a single dose of 10 Gy (dose rate 1 Gy/min) and 6 Gy (dose rate 0.75 Gy/min), respect- ively. The expression of VIRMA gene (RNA methylase) was inhibited by lipofection of A549 cells and MLE-12 cells with shRNA-VIRMA plasmid and siRNA-VIRMA interfering fragment, respectively. Quantification of m6A RNA methylation was performed by colorimetry. Changes in the expression of mRNAs of VIRMA, GATA3, and epithelial-mesenchymal transition (EMT) markers in irradiated A549 and MLE-12 cells were determined by qRT-PCR. Changes in the expression of VIRMA,  GATA3,  and  EMT  marker  proteins  in  irradiated  A549  and  MLE-12  cells  were  determined  by  Western  blot. Results: Radiation up-regulated the expression of methylase VIRMA in A549 and MLE-12 cells, which in turn enhanced the m6A of total RNA and the expression of GATA3 gene and protein, resulting in EMT. Furthermore, in A549 and MLE-12 cells, interference of the VIRMA gene significantly reduced the expression of GATA3 gene and protein and the expression of EMT-related molecules. Conclusion　 Radiation induces m6A modification in alveolar epithelial cells, which up-regu- lates the expression of GATA3 gene and induces EMT, thus playing an important role in the process of radiation-induced lung injury.

The biological effects of low-dose radiation (LDR) are still a research hotspot in the field of radiobiology. As research deepens on LDR-induced biological effects and the mechanisms, growing evidence shows that LDR produces distinct biological effects from high-dose radiation, which questions the linear non-threshold model. This article reviews LDR-induced bystander effect, hormesis, adaptive response, and hyper-radiosensitivity, as well as the mechanisms, in order to provide a reference for the transformation of basic research on LDR-related biological effects to clinical application.

N 6-methyladenosine (m 6A) is the most abundant RNA base modification in mammals, especially in eukaryotic messenger RNA (mRNA). N 6-methyladenosine modification can regulate RNA splicing, translocation, stability and ultimately affect protein synthesis. m 6A modification is catalyzed by RNA writers, reduced by erasers and also be recognized by readers. Abnormal changes ofm 6A levels are closely related to tumor occurrence and development, including proliferation, growth, invasion and metastasis. In the process of tumor radiotherapy, m 6A modification affects the efficacy of radiotherapy by affecting DNA damage, tumor stem cell generation and tumor cell radiation sensitivity. This article reviews the role of m 6A-modified epigenetic regulation in malignant tumors and the research progress of its mechanism in tumor radiotherapy, in order to provide new ideas for the development of clinical tumor molecular targeted therapies and radiosensitizers.

Objective To investigate the effect of neuropilin-1 (NRP1) on radiation-induced epithelial-mesenchymal transition (EMT) by measuring the expressions of EMT-related transcription factors in the irradiated cells with different levels of NRP 1.Methods Human lung type Ⅱ epithelial cells (A549) were transfected with NRP1 over-expression lentiviral vector and NRP1 inhibition vector to construct two cell models of NRP1high-A549 and NRP1low-A549.A NRP1 knock-down cell model was also constructed by transferring siNRP1 into normal mouse lung epithelial MLE-12 cells that was validated at both protein and mRNA levels.A single dose of 10 Gy X-ray was delivered to these cell models,then total protein and RNA were extracted at 0,12,24 and 48 h after irradiation.The expressions of EMT-related transcription factors (Twist and ZEB1) and EMT markers (β3-catenin,N-cadherin,and Vimentin) in each cell model were detected by Western blot and qPCR.Results After 10 Gy irradiation,the expressions of NRP1 mRNA and protein were significantly increased in A549 and MLE-12 cells.The expressions of the mesenchymal markers (Vimentin and N-cadherin) and the transcription factors of ZEB1 and Twist were also significantly increased (A549:t=2.917,7.361,4.852,9.278,P＜0.01;MLE-12:t=9.652,31.357,30.985,17.266,P ＜0.01).The expressions of Vimentin and N-cadherin were significantly decreased in NRP1low-A549 (t =10.077,15.707,P ＜ 0.01) and siNRP1-MLE-12 cells (t =5.745,P ＜ 0.01),but the expression of epithelial marker (β3-catenin) was significantly increased in these cells.The expressions of N-Cadherin and Vimentin were significantly elevated (t =16.055,5.560,P ＜ 0.01),while β-catenin decreased significantly in NRP1high-A549 cells.After irradiation,the transcription factor of Twist in NRP1low-A549 group was significantly decreased (t=3.987,P＜0.01),while the transcription factors of ZEB1 and Twist in the NRP1high-A549 group increased in a time-dependent manner (t =11.289,2.903,P＜0.01).After irradiation,the transcription factor of ZEB1 decreased significantly in siNRP1-MLE-12 cells (t=13.449,P＜0.01),and the protein expressions of ZEB1 and Twist in siNRP1-MLE-12 cells were lower than those of control group in a time-dependent manner.Conclusions NRP1 promotes radiation-induced EMT in human and mouse epithelial cells through up-regulation of transcription factors of ZEB1 and Twist.

Objective:To detect the expression levels of neuropilin1 (NRP1)mRNA and miR-9 in non-small cell lung cancer (NSCLC)tissue samples, and to explore the correlations between the expressions of NRP1 mRNA, miR-9 and the clinicopathological characteristics of the patients with NSCLC.Methods:Informed consent was obtained from each patient before surgery.The tissue samples including 45 NSCLC tissue ,45 adjacent carcinoma tissue and 45 normal lung tissue were collected from China-Japan Union Hospital of Jilin University from 2010 to 2011.qRT-PCR was used to detect the expression levels of NRP1 mRNA and miR-9 in three kinds of lung tissue, and the correlation between the expressions of NRP1 mRNA, miR-9 and clinicopathological characteristics of the patients with NSCLC was analyzed.Results:Compared with normal tissue,the expression level of NRP1 mRNA in adjacent carcinoma tissue had no change (P>0.05),but the expression level of NRP1 mRNA in non-small cell lung cancer tissue was significantly decreased (P<0.05).Compared with normal tissue,the expression level of miR-9 in adjacent carcinoma tissue had no change (P>0.05),but the expression level of miR-9 in non-small cell lung cancer tissue was significantly increased (P < 0.05 ). Furthermore, in adjacent carcinoma tissue, the expression level of miR-9 in the males was lower than that in the females (P<0.05 ). In NSCLC tissue, the expression level of NRP1 mRNA had no relationship with sex,age,differentiation degree,TNM stage and clinical stage,but was significantly correlated to the histological subtype and lymph node metastasis (P<0.05).In NSCLC tissue,the expression level of miR-9 had no relationship with age, pathological type, lymph node metastasis, differentiation degree,TNM stage,and clinical stage (P>0.05),but was correlated to the sex (P<0.05). Conclusion:The expression level of miR-9 is up-regulated and the expression level of NRP1 mRNA is down-regulated significantly in non-small cell lung cancer tissue. The detection of the expression level of NRP1 mRNA contributes to j udge the histological subtype and lymph node metastasis of NSCLC.

Objective To analyze the effect of high and low dose radiation on the expressions of Th1,Th2 and Th3 /Tr1 related-genes in mice thymocytes and investigate the possible underlying molecular mechanism.Methods ICR mice were randomly divided into low-dose group (0.075 Gy),high-dose group (2.0 Gy) and sham-control group.The mouse thymus tissue was extracted at 16 hours after irradiation and the expressions of Th1-Th2-Th3 related genes were measured by PCR array.Results Eight genes were up-regulated and five genes were down-regulated after low dose radiation (0.075 Gy);while 54 genes were up-regulated and three genes were down-regulated after high dose (2.0 Gy) radiation.These genes included Th1 cell related genes,Th2 cell related genes,Th3/Tr1 cell related genes,Th1/Th2 immune response genes and transcription factor related genes.Low dose radiation induced up-regulation of Stat4 and Socs1 of genes related to the Th1 cells,and it induced down-regulation of IL-4ra,Cebpb,Gata3 and Tgfb3 associated with Th2 and Th3 cells,which lead to Sftpd genes up-regulation of Th1 immune response eventually.The high dose radiation up-regulated all of Th1,Th2 and Th3/Tr related genes and also enhanced the expressions of Cd86,IL-18,IL-10 and Irf4 genes related to Th2 immune response,but it did not alter the gene expression of Th1 immune response.Conclusions Low-dose radiation induces Th1-type immune response,while high doses radiation triggers Th2 type immune response.

Objective To explore the effect of miR-9 on the expression of NRP1 and its radiation effects in A549 cells.Methods Bioinformatics was used to analyze the potential binding sites of has-miR-9 and NRP1-3'UTR.The miR-9 sequence was inserted into pcDNA-DEST-47 plasmid to construct the eukaryotic expression vector (pcDNA-DEST-miR-9) and to construct the NRP1 gene 3'UTR luciferase reporter plasmid (pEZX-MT05) at the same time.They were simultaneously transferred into A549 cells for analysis of the regulatory effect of miR-9 on the expression of NRP1.Meanwhile miR-29b was used as a negative control to observe whether or not NRP1 gene was a target of miR-9.After 10 Gy irradiation,the expression of NRP1,and the inhibitory effect of miR-9 on it was confirmed by Western blot assay.The expression of miR-9 was detected by real-time PCR.Results It was found that miR-9 reduced the luciferase activity of NRP1-3'UTR wild plasmid (t =3.906,P ＜ 0.05) but not NRP1-3' UTR mutant plasmid.This luciferase activity was not inhibited by other types of miRNA (miR-29b).The expression of NRP1 protein in A549 cells was decreased after the cells were transfected with miR-9 mimic.After irradiation with dose of 10 Gy,the expression of miR-9 were decreased (t =37.319,P ＜ 0.05) and the expression of NRP1 protein were increased.Conclusions miR-9 regulates the expression of NRP1 by targeting 3'UTR site of NRP1 gene in A549 cells.