Objective To investigate the effects of circular RNA APLP2(circAPLP2)on the proliferation,migra-tion,and invasion of human colorectal cancer(CRC)cell lines by regulating microRNA-455-3p(miR-455-3p)/Stathmin1(STMN1)axis.Methods RT-qPCR was used to detect the expression of circAPLP2,miR-455-3p and STMN1 in CRC and normal colorectal cell lines and the optimal cell line was screened.Proliferation,migra-tion and invasion were detected by MTT assay,scratch assay and Transwell assay,respectively.The relationship between circAPLP2 and miR-455-3p,between miR-455-3p and STMN1 was confirmed by dual Lucifer's reporter gene assay.Results CircAPLP2 and STMN1 were highly expressed in CRC cells,miR-455-3p showed a low ex-pression.Knocking down circAPLP2 resulted in a decrease in rate of survival and of scratch healing rate and in-vasion of SW620 cells,An up regulation of miR-455-3p expression,a down regulation of STMN1,cyclin D1,N-cadherin protein expression and an up regulation of E-cadherin protein expression were also found(P<0.05).Inhibition of miR-455-3p expression reversed inhibitory effect of knocking down circAPLP2 on SW620 cell prolif-eration,migration,and invasion,up-regulated the STMN1,cyclin D1 and N-cadherin protein expression,and down-regulation of E-cadherin protein expression(P<0.05).Dual luciferase reporter gene assay showed that circAPLP2 targeted at negative regulation of miR-455-3p expression,while miR-455-3p targeted at negative reg-ulation of STMN1 expression.Nude mouse transplantation experiment found that knocking down circAPLP2 affect-ed the growth of transplanted tumors,while miR-455-3p expression was up-regulated and STMN1 expression was down-regulated(P<0.05).Conclusions CircAPLP2 inhibits the proliferation,migration and invasion of colorectal cancer cell lines by regulating the miR-455-3p/STMN1 axis.

Objective: To explore the changes in ribosomal DNA copy number in peripheral blood among patients with pneumoconiosis and its influencing factors, so as to provide insights into prevention and treatment of pneumoconiosis. Methods: Eighty-eight patients with pneumoconiosis who visited a designated hospital and 71 community residents with no history of pneumoconiosis or dust exposure were selected as the pneumoconiosis group and control group, and age, smoking history, drinking history and cumulative years of exposure to dust were collected through questionnaire surveys. The copy number of 45S rDNA and 5S rDNA was detected using real-time fluorescence quantitative PCR, and the differences between the two groups were compared. Factors affecting the copy number of 45S rDNA and 5S rDNA were identified by a multiple linear regression model. Results: The pneumoconiosis group had a median age of 56.00 (interquartile range, 15.25) and a mean cumulative dust exposure duration of (12.40±8.08) years, with 56.82% smoking and 62.50% drinking. The control group had a median age of 64.00 (interquartile range, 37.00) years, with 32.39% smoking and 26.76% drinking. The median copy number of 45S rDNA in the pneumoconiosis group was 1.29 (interquartile range, 0.59), which was lower than 2.10 (interquartile range, 1.88) in the control group; the median copy number of 5S rDNA in the pneumoconiosis group was 5.33 (interquartile range, 0.85), which was higher than 4.66 (1.34) in the control group (both P<0.05). Multiple linear regression analysis identified age (β=-0.034) and pneumoconiosis (β=-1.595) as factors affecting 45S rDNA copy number, age (β=-0.013) as a factor affecting 5S rDNA copy number, and age (β=0.018) as a factor affecting 5S rDNA copy number in the pneumoconiosis group (all P<0.05). Conclusions Compared with community residents with no history of pneumoconiosis or dust exposure, the copy number of 45S rDNA in peripheral blood among patients with pneumoconiosis is reduced and the copy number of 5S rDNA is increased.

ObjectiveThis study aimed to investigate the current status of biosafety management in laboratory animal institutions in Hunan Province, identify management shortcomings, and provide targeted recommendations for improvement. MethodsA questionnaire survey was conducted in July 2023 among 40 laboratory animal institutions in Hunan Province, covering topics such as the establishment of laboratory management system and its overall operation status, emergency management for incidents, medical waste disposal, animal transportation, personnel practitioner management, environmental disinfection, and equipment maintenance. The awareness of biosafety, animal bite incidents, and vaccination history was surveyed from at least one animal feeder or experimental operation practitioner from each institution, totaling 50 practitioners. Through literature review and comparative analysis, this paper analyzed the current status of biosafety management in production, transportation, and use of laboratory animals in Hunan Province from aspects such as biosafety management systems, personnel training, disinfection of environmental facilities and waste disposal, and provided recommendations. ResultsAmong the 40 laboratory animal institutions in Hunan Province,39 institutions (97.5%) had established laboratory management systems, 37 (92.5%) had emergency response plans for incidents of to transport laboratory animals, 15 (37.5%) had complete records of emergency drills for laboratory animal biosafety, and 39 (97.5%) had established protocols for carcass and waste management. Moreover, 26 institutions (65.0%) had laboratory biosafety risk assessment reports. 4 out of 8 (50.0%) production units had emergency plans for animal transportation, with 7 (87.5%) using special vehicles to transport laboratory animals. 2 (4.0%) of the 50 practitioners were unaware of emergency response plans, 6 participants (12.0%) did not consistently wear personal protective equipment, and 38 participants (76.0%) had been bitten or scratched by laboratory animals. The results of the survey showed that emergency management, transportation management and personnel management of laboratory animal incidents still need improvement in Hunan Province. Relevant functional departments should strengthen supervision and management efforts, establish local regulations for the transportation management of laboratory animals, ensure strict compliance with relevant documents, conduct emergency drills in all units, and strengthen training for practitioners. ConclusionWhile daily management practices in the 40 laboratory animal institutions in Hunan Province are generally satisfactory, there remains a need for further improvement in emergency management, transportation management, personnel management, etc. Gradually enhancing the level of laboratory animal safety management is essential to collectively safeguard public health safety.

The emergency management of biosafety for laboratory animals in Hunan Province is an essential component of the province's implementation of the national biosafety strategy.To strengthen the prevention and control of biosafety risks in laboratory animals and to ensure a quick and effective response to laboratory animal biosafety emergencies,Hunan Province has formulated the"Emergency Response Plan for Laboratory Animal Biosafety Emergencies in Hunan Province".This plan aims to minimize damages caused to practitioners,public health,and laboratory animal industry,protect lives and property,and safeguard public safety and social stability.This paper analyzes the necessity,guiding ideology,principles,and basis for formulating the plan.It details the main contents of the plan,which includes scope of application,incident classification,organizational structure and responsibilities,monitoring and early warning mechanisms,emergency reporting and response,post-incident assessment,and safeguard measures.Moreover,this paper provides a summary and outlook on the emergency management of biosafety laboratory animals in Hunan Province in recent years.

Objective: To investigate the effect of ribosomal DNA (rDNA) copy number variation caused by hexavalent chromium exposure on DNA damage response in different cell lines, so as to provide insights into the involvement of hexavalent chromium-induced rDNA copy number variation in DNA damage responses. : Methods Human lung epithelial BEAS-2B cells and human embryonic lung MRC-5 cells were treated with 2 μmol/L potassium dichromate for 24 hours, and then cells were transferred to fresh media for further incubation, while cells treated with the same volume of phosphate buffer solution served as controls. Cells treated with potassium dichromate for 24 hours, and 3 and 7 days post-detoxification, were harvested, and rDNA copy number was quantified in cells using a quantitative fluorescent real-time PCR assay. Cell cycle, apoptosis and DNA damage were detected using a Muse cell analyzer, and the DNA damage was evaluated with the proportion of ataxia telangiectasia-mutated (ATM) gene activation, proportion of double-strand DNA breaks and the percentage of the H2A.X variant histone phosphorylatio. : Results The 45S and 5S rDNA copy numbers of were significantly higher in MRC-5 cells than in BEAS-2B cells [(1.54±0.26) vs. (1.02±0.18), P<0.05; (6.97±1.07) vs. (3.00±0.15), P<0.05]. The 45S rDNA copy number was lower in MRC-5 cells 3 days post-detoxification (0.80±0.04) than in controls (P<0.05), and was higher in BEAS-2B cells 3 days post-detoxification (1.43±0.07) than in controls (P<0.05) . G0/G1 phase arrest was found in MRC-5 cells 24 hours post-treatment, and the apoptotic rates were significantly higher in MRC-5 cells 3 and 7 days post-detoxification than in controls [(11.53±1.53)%, (18.33±0.70)% vs. (3.53±0.93)%, P<0.05]. The overall apoptotic rates 24 hours post-treatment and 3 days post-detoxification [(2.80±0.17)%, (3.33±0.57)% vs. (1.53±0.61)%, P<0.05], proportion of ATM gene activation 3 days post-detoxification [(3.37±0.67%) vs. (1.18±0.22)%, P<0.05], proportion of double-strand DNA breaks 3 days post-detoxification [(4.45±0.85)% vs. (0.97±0.21)%, P<0.05] and percentage of the H2A.X variant histone phosphorylation 3 days post-detoxification [(1.68±0.56)% vs. (0.29±0.06)%, P<0.05] in BEAS-2B cells were higher than in controls. Conclusions Hexavalent chromium-induced rDNA copy number variation affects DNA damage response in different cell lines. A stronger DNA damage response is found in BEAS-2B cells with a low rDNA copy number, and a relative stable response is observed in MRC-5 cells with a high rDNA copy number.

Objective: To investigate the effect of chrysotile exposure on ribosomal DNA (rDNA) copy number and DNA damage response, so as to provide insights into the mechanism of asbestos-induced carcinogenesis. Methods: Human pleural mesothelial MeT-5A cells were treated with chrysotile suspensions at doses of 1.25, 2.5 and 5 μg/cm2 (low-, medium-, high-dose group), while PBS served as controls. MeT-5A cells were harvested 6, 24, 48 and 72 h post-treatment, and the rDNA copy numbers and the BIRC5, HRAS, GINS4 and RRM2 mRNA expression were determined using a quantitative real-time PCR (qPCR) assay. The apoptosis of MeT-5A cells and DNA damage were detected using Muse cell analyzer. The rDNA copy numbers, DNA damage responses and BIRC5, HRAS, GINS4 and RRM2 mRNA expression were compared in MeT-5A cells treated with different doses of chrysotile suspensions. Results: There were significant differences in 45S rDNA copy numbers among low-, medium-, high-dose groups and the control groups 6, 48 and 72 h post-treatment with chrysotile suspensions, and significantly lower 45S rDNA copy numbers were measured in low-, medium- and high-dose groups than in the control group 6 h post-treatment, while significantly higher 45S rDNA copy numbers were found in the high-dose group than in low- and medium-dose groups 48 and 72 h post-treatment (all P<0.05). There were significant differences in 5S rDNA copy numbers among low-, medium-, high-dose groups and the control groups 24, 48 and 72 h post-treatment with chrysotile suspensions, and significantly lower 5S rDNA copy numbers were measured in medium- and high-dose groups than in the control group 24 and 48 h post-treatment, while significantly lower 5S rDNA copy numbers were found in medium- and high-dose groups than in the low-dose group 24, 72 h post-treatment (all P<0.05). There were significant differences in the overall apoptotic rate of MeT-5A cells among groups at different time points, and the overall apoptotic rate of MeT-5A cells were significantly higher in medium- and high-dose groups than in the control group (all P<0.05), with late-stage apoptosis predominantly detected. There were significant differences in the rates of ATM activation and DNA double-strand break in MeT-5A cells among groups 72 h post-treatment, and higher rates of ATM activation and DNA double-strand break were measured in medium- and high-dose groups than in the control group (all P<0.05). In addition, there were significant differences in the relative mRNA expression of BIRC5, HRAS, GINS4 and RRM2 genes among groups 24 and 48 h post-treatment, and significantly lower BIRC5, HRAS, GINS4 and RRM2 mRNA expression was quantified in medium- and high-dose groups than in the control group (all P<0.05). Conclusion Exposure to chrysotile may induce rDNA copy number variations and altered expression of nucleolar proteins in human pleural mesothelial cells, which may be involved in the regulation of DNA damage responses.