ABSTRACT
Arsenic is a potent toxic heavy metal found in the environment that can causes health problems, including liver disease in humans and animals. Chronic exposure to arsenic remains an environmental health problem worldwide, affecting hundreds of millions of people. Although the oxidative stress and apoptosis induced by arsenic have been confirmed, the underlying mechanism of apoptosis has not been fully elucidated. The purpose of this study is to investigate whether sodium arsenite (SA)induced liver toxicity is related to the regulation of DNA replication and repair pathways. The results of MTT and microscopy showed that SA has an inhibitory effect on the proliferation of human hepatocytes (L02), and this effect is time and concentration dependent. Flow cytometry detected the effects of different concentrations of SA on L02 cells. Compared with the control group, high concentrations of SA significantly affected the L02 cell cycle. In addition, RNA sequencing results showed that the differentially expressed genes in cells after SA treatment were concentrated in the DNA replication process and repair pathways. The effect of SA treatment on the expression of human RECQ DNA helicase and repair genes was further confirmed by Western blot and real-time quantitative PCR. In vitro study showed that SA treatment inhibited cell proliferation, and induced apoptosis as well as DNA damage and cell cycle arrest of human liver cell L02. Collectively, these results indicate that arsenic poisoning is related to the regulation of DNA replication and repair pathways, which provides insight for understanding the molecular mechanism of arsenic poisoning.
ABSTRACT
Objective To investigate the correlation between the expression level of BLM and its clinical significance in leukemia.Methods 125 bone marrow specimens of inpatients and outpatients with leukemia were collected in Anhui provincial hospital from January 2011 to December 2011.125 leukemia patients were diagnosed and classified into acute leukemia (AL,n =66) and chronic myelogenous leukemia (CML,n =59) by Morphologic and Immunologic criteria,5 non-tumor individuals were included as control group.The BLM mRNA expressions were by reverse transcription-polymerase chain reaction(RT-PCR).The specimens were devided into groups according to the age,gender,leukemia type,peripheral blood leukocyte counts,hepatomegalia and(or) splenomegaly,fusion gene,chromosome karyotype,whether first visit and transplantation.The expression of BLM gene in each group and the correlation with above factors were retrospectively analysed.The statistical methods such as chi-square test,single factor variance analysis,t test and Pearson correlation test were mainly used.Results BLM mRNA was detected in leukemia.In bone marrow cells,the BLM gene expression was positive in 71 patients and negative in 54 patients.But none of 5 non-tumor bone marrow cells expressed BLM gene.The difference of BLM expression between patients and controls was statistically significant in two groups,i.e.peripheral blood leukocyte counts and fusion gene (x2 =14.730,22.399 ; P ＜ 0.05),but there is no statistical significant differences in other groups.The expressions of BLM mRNA in leukemia patients who had been treated with chemotherapy were lower than those newly diagnosed (0.1788 ± 0.1091 vs 0.3276 ± 0.2016 ; P ＜ 0.05).Moreover,BLM mRNA level in post-bone marrow transplant patients was lower than those not treated (0.1271 ± 0.1009 vs 0.2902 ±0.2034 ; P ＜ 0.05).Pearson correlation analysis showed that higher BLM mRNA expression positively correlated with fusion gene (r =0.357,P ＜ 0.01) and chromosome abnormality (r =0.279,P ＜ 0.05).Conclusion The BLM mRNA expression level of measurement can be used as judgment for leukemia patients disease severity and the index of prognosis,testing the level may provide a basis for clinical and curative effect judgment.