The role of heavy metals in the development of colorectal cancer.

OBJECTIVE: To investigate the relationship among 18 heavy metals, microsatellite instability (MSI) status, ERCC1, XRCC1 (rs25487), BRAF V600E and 5 tumor markers and their role in the development of colorectal cancer (CRC). METHODS: A total of 101 CRC patients and 60 healthy controls were recruited in the present study. The levels of 18 heavy metals were measured by ICP-MS. MSI status and the genetic polymorphism were determined by PCR (FP205-02, Tiangen Biochemical Technology Co., Ltd., Beijing, China) and Sanger sequencing. Spearman's rank correlation was used to analyze the relationship among various factors. RESULTS: The level of selenium (Se) was lower in the CRC group compared with the control group (p < 0.01), while vanadium (V), arsenic (As), tin (Sn), barium (Ba) and lead (Pb) were higher (p < 0.05), chromium (Cr) and copper (Cu) were significantly higher (p < 0.0001) in the CRC group than those in the control group. Multivariate logistic regression analysis indicated that Cr, Cu, As and Ba were the risk factors for CRC. In addition, CRC was positively correlated with V, Cr, Cu, As, Sn, Ba and Pb, but negatively correlated with Se. MSI was positively correlated with BRAF V600E, but negatively correlated with ERCC1. BRAF V600E was positively correlated with antimony (Sb), thallium (Tl), CA19-9, NSE, AFP and CK19. XRCC1 (rs25487) was found to be positively correlated with Se but negatively correlated with Co. The levels of Sb and Tl were significantly higher in the BRAF V600E positive group compared to the negative group. The mRNA expression level of ERCC1 was significantly higher (P = 0.035) in MSS compared to MSI. And there was a significant correlation between XRCC1 (rs25487) polymorphism and MSI status (P<0.05). CONCLUSION: The results showed that low level of Se and high levels of V, As, Sn, Ba, Pb, Cr, and Cu increased the risk of CRC. Sb and Tl may cause BRAF V600E mutations, leading to MSI. XRCC1 (rs25487) was positively correlated with Se but negatively correlated with Co. The expression of ERCC1 may be related to MSS, while the XRCC1 (rs25487) polymorphism is related to MSI.

LncRNA AK077216 affects the survival of colorectal adenocarcinoma patients via miR-34a.

BACKGROUND AND STUDY AIMS: It has been reported that long non-coding RNA (lncRNA) AK077216 involves in osteoclastogenesis and bone resorption. Our preliminary data has revealed that AK077216 was downregulated in colorectal adenocarcinoma (CRA) and it was closely correlated with miR-34a. This study was carried out to explore the role of AK077216 in CRA with a focus on its interactions with miR-34a. PATIENTS AND METHODS: Paired CRA and non-tumor tissues collected from 66 CRA patients were subjected to RNA preparations, followed by RT-qPCRs to determine the expression levels of AK077216 and miR-34a. The interactions between AK077216 and miR-34a were analyzed with overexpression assays. Transwell assays were carried out to explore the roles of AK077216 and miR-34a in regulating CRA cell invasion and migration. RESULTS: AK077216 was downregulated in CRA tissues compared to that in non-tumor tissues of CRA patients. During a 5-year follow-up, patients with lower expression levels of AK077216 in CRA tissues showed significantly lower overall survival. MiR-34a was upregulated in CRA tissues and inversely correlated with AK077216. Overexpression of AK077216 decreased the expression levels of miR-34a, while overexpression of miR-34a did not affect the expression of AK077216. Overexpression of AK077216 inhibited CRA cell migration and invasion, while overexpression of miR-34a accelerated cancer cell migration and invasion and attenuated the effects of overexpression on AK077216 on cell behaviors. CONCLUSION: Therefore, AK077216 may inhibit CRA cell migration and invasion by downregulating miR-34a.

Impact of Different Biochars on Microbial Community Structure in the Rhizospheric Soil of Rice Grown in Albic Soil.

The purpose of this study was to clarify the effects of biochar on the diversity of bacteria and fungi in the rice root zone and to reveal the changes in soil microbial community structure in the root zone after biochar application to provide a scientific basis for the improvement of albic soil. Rice and corn stalk biochar were mixed with albic soil in a pot experiment. Soil samples were collected at the rice maturity stage, soil nutrients were determined, and genomic DNA was extracted. The library was established using polymerase chain reaction (PCR) amplification. The abundance, diversity index, and community structure of the soil bacterial 16SrRNA gene V3 + V4 region and the fungal internal transcribed spacer-1 (ITS1) region were analyzed using Illumina second-generation high-throughput sequencing technology on the MiSeq platform with related bioinformatics. The results revealed that the biochar increased the soil nutrient content of albic soil. The bacteria ACE indexes of treatments of rice straw biochar (SD) and corn straw biochar (SY) were increased by 3.10% and 2.06%, respectively, and the fungi ACE and Chao indices of SD were increased by 7.86% and 14.16%, respectively, compared to conventional control treatment with no biochar (SBCK). The numbers of bacterial and fungal operational taxonomic units (OUT) in SD and SY were increased, respectively, compared to that of SBCK. The relationship between soil bacteria and fungi in the biochar-treated groups was stronger than that in the SBCK. The bacterial and fungal populations were correlated with soil nutrients, which suggested that the impacts of biochar on the soil bacteria and fungi community were indirectly driven by alternation of soil nutrient characteristics. The addition of two types of biochar altered the soil microbial community structure and the effect of rice straw biochar treatment on SD was more pronounced. This study aimed to provide a reference and basic understanding for albic soil improvement by biochar, with good application prospects.

The OsABF1 transcription factor improves drought tolerance by activating the transcription of COR413-TM1 in rice.

Water deprivation causes substantial losses in crop yields around the world. In this study, we show that when overexpressed in transgenic rice (Oryza sativa), the bZIP transcription factor OsABF1 confers distinctly different drought-tolerance phenotypes when tethered to the transcriptional activator VP16 versus the transcriptional repressor EAR. We performed chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq) assays on transgenic rice lines and determined that OsABF1 binds to DNA sequences containing an ACGT core motif. Analysis of the overlap between the RNA-sequencing and chromatin immunoprecipitation-sequencing data identified 242 OsABF1 target genes involved in multiple aspects of the drought response. Overexpression of one of these genes, COR413-TM1, which encodes a putative thylakoid membrane protein, resulted in a drought-tolerance phenotype without obvious side effects. In addition, OsABF1 directly regulates the expression of the protein phosphatase 2C (OsPP48 and OsPP108) and bZIP (OsbZIP23, OsbZIP46, and OsbZIP72) genes, thus forming a complex feedback circuit in the drought/abscisic acid signaling pathway.