IGF2BP3 promotes mRNA degradation through internal m7G modification.

Recent studies have suggested that mRNA internal m7G and its writer protein METTL1 are closely related to cell metabolism and cancer regulation. Here, we identify that IGF2BP family proteins IGF2BP1-3 can preferentially bind internal mRNA m7G. Such interactions, especially IGF2BP3 with m7G, could promote the degradation of m7G target transcripts in cancer cells. IGF2BP3 is more responsive to changes of m7G modification, while IGF2BP1 prefers m6A to stabilize the bound transcripts. We also demonstrate that p53 transcript, TP53, is m7G-modified at its 3'UTR in cancer cells. In glioblastoma, the methylation level and the half lifetime of the modified transcript could be modulated by tuning IGF2BP3, or by site-specific targeting of m7G through a dCas13b-guided system, resulting in modulation of cancer progression and chemosensitivity.

Quantitative profiling of m6A at single base resolution across the life cycle of rice and Arabidopsis.

N6-methyladenosine (m6A) plays critical roles in regulating mRNA metabolism. However, comprehensive m6A methylomes in different plant tissues with single-base precision have yet to be reported. Here, we present transcriptome-wide m6A maps at single-base resolution in different tissues of rice and Arabidopsis using m6A-SAC-seq. Our analysis uncovers a total of 205,691 m6A sites distributed across 22,574 genes in rice, and 188,282 m6A sites across 19,984 genes in Arabidopsis. The evolutionarily conserved m6A sites in rice and Arabidopsis ortholog gene pairs are involved in controlling tissue development, photosynthesis and stress response. We observe an overall mRNA stabilization effect by 3' UTR m6A sites in certain plant tissues. Like in mammals, a positive correlation between the m6A level and the length of internal exons is also observed in plant mRNA, except for the last exon. Our data suggest an active m6A deposition process occurring near the stop codon in plant mRNA. In addition, the MTA-installed plant mRNA m6A sites correlate with both translation promotion and translation suppression, depicting a more complicated regulatory picture. Our results therefore provide in-depth resources for relating single-base resolution m6A sites with functions in plants and uncover a suppression-activation model controlling m6A biogenesis across species.

Expression patterns and prognostic role of m6A RNA methylation regulators in Non-small Cell Lung Cancer.

To investigate the expression pattern and prognostic role of m6A RNA methylation regulators in non-small cell lung cancer (NSCLC), we downloaded data from 422 patients from The Cancer Genome Atlas (TCGA) database. The relationship between the expression levels of m6A RNA methylation regulators and clinicopathological variables of NSCLC was analysed using R language. By analysing glioma data in TCGA, we found that a prognostic risk score model could be constructed based on 18 genes with m6A methylation modification. m6A gene alterations were significantly associated with tumour grade and tumour stage. Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression models were used to identify 2 m6A RNA methylation modifiers: IFG2BP2, and METTL14 to construct risk profiles. Based on the risk profile, patients were divided into high-risk and low-risk groups. The overall survival rate of the low-risk group was significantly higher than that of the high-risk group. The results suggest that the prognostic risk score model constructed by m6A methylation regulators can predict the prognosis of glioma patients. IFG2BP2 and METTL14 may be the key m6A methylation regulators involved in the development of NSCLC and can be used as the molecular markers for the prognosis of NSCLC.

Efficacy and safety of letrozole or anastrozole in the treatment of male infertility with low testosterone-estradiol ratio: A meta-analysis and systematic review.

BACKGROUND: Aromatase inhibitors (AIs) have been used to treat male infertility for decades. However, due to the lack of large-scale randomized controlled studies and basic research, the efficacy and safety of AIs in the treatment of male infertility remain controversial. Therefore, it is necessary to conduct an evidence-based preliminary evaluation of the existing clinical trials of AIs in the treatment of male infertility. METHOD: A comprehensive literature search was performed in the PubMed, Embase, Cochrane, CNKI, VIP, CBM, and Wanfang databases through August 2021 for all studies. We conducted a systematic review with a meta-analysis of all available studies reporting sperm conventional parameters, gonadotropin and testosterone levels, and/or the pregnancy rate. RESULTS: A total of 10 studies involving 666 patients were included. Letrozole (LE) or anastrozole (AZ) administration significantly increased sperm concentration, total sperm count, serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) levels, and the testosterone-to-estradiol ratio (T/E2), but E2 levels were significantly reduced compared with baseline values. Compared with the control group, which included selective estrogen receptor modulators (SEMRs) or human chorionic gonadotropin (HCG), LE, or AZ did not have any significant effect on sperm concentration, motility, and morphology, except that AIs had less effect on sperm motility than the control group (weighted mean difference [WMD]: -2.55; 95% CI: -4.11 to -1.00; p = 0.001). CONCLUSION: AIs may be effective in the treatment of male infertility. For infertile male patients planning assisted reproduction, discontinuation of AIs for 2-7 days prior to sperm retrieval may increase the success rate of fertilization. Further studies with larger sample sizes are needed to validate these findings.

MiR-4429 Alleviates Malignant Behaviors of Lung Adenocarcioma Through Wnt/ß-Catenin Pathway.

Lung adenocarcinoma (ADC) is a common subtype of non-small cell lung cancer. MicroRNAs have been reported to be effective biomarkers for diagnosis and an important target for therapy. MiR-4429 is a newly identified miRNA, which can take part in tumor progression as a tumor inhibitor. Moreover, it is an exosomal miRNA that can be taken by lung ADC cell line A549. Nevertheless, its role in lung ADC has been poorly studied. This research discovered that miR-4429 was low expressed in lung ADC cells. MiR-4429 mimics could alleviate the capacities of cell proliferation and metastasis. The mimics are able to reverse epithelial-mesenchymal transition at the same time. Furthermore, it was verified that miR-4429 could bind to ß-catenin and negatively regulate ß-catenin expression. Interestingly, SKL2001 can reverse the role of miR-4429 on tumor. Consequently, miR-4429 can inactivate Wnt/ß-catenin signaling pathway by targeting ß-catenin and prevent oncogene expression in lung ADC cells.

Sesamin induces cell cycle arrest and apoptosis through p38/C-Jun N-terminal kinase mitogen-activated protein kinase pathways in human colorectal cancer cells.

Sesamin, a lignan compound, exhibits a variety of biological activities and possesses potent anticancer properties on some human cancers. However, its effect on human colorectal cancer (CRC) remains to be elucidated. To investigate the effects of sesamin on CRC cells and further to explore the mechanisms, cell viability, cell cycle and apoptosis assays were performed in this study. We found that sesamin had a selective antiproliferation of CRC cell line HCT116 in a dose- and time-dependent manner, but no obvious effect on human normal colorectal mucosa epithelial cell FHC. Further study showed that sesamin-induced cell cycle arrest and decreased the expression of Cyclin D1 significantly and dose-dependently in HCT116 cells. Moreover, sesamin dose-dependently triggered apoptosis of HCT116 but not FHC, and promoted the expression levels of proapoptotic biomarkers Bax, cleaved caspase-3 and cleaved PARP-1 and inhibited the expression of antiapoptotic biomarker Bcl-2. Western blot analysis was used to reveal the possible signaling pathways, and we found that sesamin upregulated the phosphorylation expression levels of C-Jun N-terminal kinase (JNK) and p38 except ERK1/2 in a dose-dependent way in both HCT116 and another CRC cell line SW480. Moreover, we found that the apoptosis effect induced by sesamin was partially eliminated by inhibiting JNK or p38 activation. Finally, we showed that sesamin effectively reduced the growth of xenograft tumors derived from cell lines with limited toxicity. Taken together, the potential ability of sesamin to induce cell cycle arrest and apoptosis was shown to be via the p38 and JNK mitogen-activated protein kinase signaling pathways, which may be one of the mechanisms of the anticancer activity of this low-toxic agent.

[Soil enzyme activities under two forest types as affected by different levels of nitrogen deposition].

A simulation test was conducted to study the change trends of soil cellulase, polyphenol oxidase, and sucrase activities under natural broadleaf-Korean pine (Pinus koraiensis) and secondary poplar (Populus davidiana) -birch (Betula platyphylla) mixed forests as affected by 0, 25, and 50 kg x hm(-2) x a(-1) of N deposition. The results showed that the effects of elevated N deposition on test enzyme activities varied with forest type, and short-term nitrogen addition could significantly affect the test enzyme activities. High N deposition decreased soil polyphyneol oxidase activity, and correspondingly, soil cellulase and sucrase activities also had a trend of decrease.