Research on the Effect and Mechanism of Selenium on Colorectal Cancer Through TRIM32.

The intake of selenium (Se) in the human body is negatively correlated with the risk of colorectal cancer (CRC), but its mechanism in the occurrence and development of CRC is not clear. This study aimed to evaluate the therapeutic effect of Se on CRC, and explore the anti-tumor effect of Se supplementation on CRC and its molecular mechanism. In this study, we utilized colony formation assay, cell scratch test, Transwell migration, and flow cytometry to assess cell proliferation, migration, and apoptosis. Our findings demonstrate that Se effectively suppresses the growth and proliferation of CRC cell lines HCT116 and SW480 and promoting cellular apoptosis. In vivo experiments demonstrated a significant inhibitory effect of Se on tumor growth. CRC-related datasets were extracted from the Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases for differential expression analysis of TRIM32 and survival analysis. We found that TRIM32 was highly expressed in tumor tissues of CRC patients and correlated with a poor prognosis. Furthermore, through RNA sequencing analysis, we identified TRIM32 as a gene that was significantly decreased after Se treatment in HCT116 cells. This finding was subsequently validated by Western blot results. Moreover, TRIM32 knockdown combined with Se treatment significantly inhibited cell growth proliferation and migration and further induced apoptosis of colorectal cancer cells. In conclusion, our findings provided evidence that Se inhibited the growth of colorectal cancer cells by down-regulating TRIM32.

Characteristics and health risk assessment of volatile N-nitrosamines in the plasma of adults in Guangdong Province, China.

N-nitrosamines are strong carcinogens that are widely present in the environment. This study developed a method, and analyzed the concentrations of volatile N-nitrosamines (VNAs) in the plasma of adults in Guangdong Province, China. Finally, the health risks to adults in Guangdong Province, China, with dietary exposure to VNAs were assessed. Gas chromatography/mass spectrometry (GC/MS) in electron impact (EI) ionization source mode was used to quantitatively analyze VNAs, and to perform accurate mass determination. The lower limit of detection (LOD) of nine nitrosamines are ranged from 0.01 to 2.14 ng/mL. The recovery rate ranged from 83 % to 116 %, and the relative standard deviation (RSD) was < 10 %. The method developed is simple, rapid, and provides good reproducibility and high sensitivity. N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodinbutylamine (NDBA), N-nitrosopiperidine (NPIP), N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) and N-nitrosodiphenylamine (NDPhA) were detected in 92 adult plasma samples. NDMA and NMEA were detected in 56.5 % and 44.6 % of the samples, followed by NPIP (34.8 %). NDMA had the highest median concentration (43.7 ng/mL) in the total samples. There were gender-related differences found in the concentrations of NDBA and NDPhA. The exposure risk assessment results showed that the two highest daily dietary intakes of VNAs were N-nitrosodi-n-propylamine (NDPA) and NDMA, and aquatic products and pickled vegetables contributed the most total nitrosamine intake. The lifetime cancer risk of adults ranged from 2.88 × 10-10 to 7.46 × 10-5, and the risk associated with NDMA, NDPA, N-nitrosodiethylamine (NDEA), NMEA and NPIP are important and should attract more attention. This study aimed to explore the exposure levels of VNAs in the plasma of adults in Guangdong Province, China, and to assess the health risks of dietary intake of VNAs, which provides a basis of the effect of VNAs exposure on human health.