T-2 toxin induces mitochondrial dysfunction in chondrocytes via the p53-cyclophilin D pathway.

Kashin-Beck disease is an endemic joint disease characterized by deep chondrocyte necrosis, and T-2 toxin exposure has been confirmed its etiology. This study investigated mechanism of T-2 toxin inducing mitochondrial dysfunction of chondrocytes through p53-cyclophilin D (CypD) pathway. The p53 signaling pathway was significantly enriched in T-2 toxin response genes from GeneCards. We demonstrated the upregulation of the p53 protein and p53-CypD complex in rat articular cartilage and ATDC5 cells induced by T-2 toxin. Transmission electron microscopy showed the damaged mitochondrial structure of ATDC5 cells induced by T-2 toxin. Furthermore, it can lead to overopening of the mitochondrial permeability transition pore (mPTP), decreased mitochondrial membrane potential, and increased reactive oxygen species generation in ATDC5 cells. Pifithrin-α, the p53 inhibitor, alleviated the increased p53-CypD complex and mitochondrial dysfunction of chondrocytes induced by T-2 toxin, suggesting that p53 played an important role in T-2 toxin-induced mitochondrial dysfunction. Mechanistically, T-2 toxin can activate the p53 protein, which can be transferred to the mitochondrial membrane and form a complex with CypD. The increased binding of p53 and CypD mediated the excessive opening of mPTP, changed mitochondrial membrane permeability, and ultimately induced mitochondrial dysfunction and apoptosis of chondrocytes.

The efficacy and safety of neoadjuvant nimotuzumab for gastric cancer: A meta-analysis of randomized controlled studies.

INTRODUCTION: The efficacy of neoadjuvant nimotuzumab for gastric cancer remained controversial. We conducted a systematic review and meta-analysis to explore the efficacy of neoadjuvant nimotuzumab plus chemotherapy vs chemotherapy for gastric cancer. METHODS: We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through May 2019, and included randomized controlled trials assessing the efficacy of neoadjuvant nimotuzumab plus chemotherapy vs chemotherapy for gastric cancer. This meta-analysis was performed using the random-effect model. RESULTS: Four randomized controlled trials were included in the meta-analysis. There were 128 patients included in intervention group and 131 patients included in control group. Overall, compared with chemotherapy for gastric cancer, neoadjuvant nimotuzumab plus chemotherapy showed no substantial influence on response rate (risk ratio [RR] = 1.22; 95% CI = 0.78-1.89; P = .38), disease control rate (RR = 2.22; 95% confidence interval [CI] = 0.32-15.40; P = .42), rash (RR = 1.26; 95% CI = 0.96-1.66; P = .10), neutropenia (RR = 1.26; 95% CI = 0.96-1.66; P = .10), anemia (RR = 1.08; 95% CI = 0.62-1.89; P = .78), or nausea (RR = 1.19; 95% CI = 0.96-1.48; P = .12), but might improve the incidence of vomiting (RR = 1.60; 95% CI = 1.03-2.50; P = .04). CONCLUSIONS: Neoadjuvant nimotuzumab might provide no additional benefits to the treatment of gastric cancer.

[Soil enzyme activities and their stoichiometry of typical plantations in mid-subtropical China].

We measured the activities of six kinds of enzyme, including ß-glucosidase (BG), ß-N-acetyl-glucosaminidase (NAG), leucine aminopeptidase (LAP), acid phosphatase (AP), polyphenol oxidase (POX), peroxidase (POD), as well as enzyme stoichiometric ratios and soil physical and chemical properties at 0-10 and 10-20 cm layers across typical Pinus massoniana plantation, Pinus elliottii plantation and mixed plantation of P. massoniana and Schima superba (broadleaved-conifer mixed plantation) in mid-subtropical China. Key factors driving the variation in soil enzyme activity and stoichiometry among different stand types were investigated. The results showed that the activities of soil BG and LAP were significantly affected by stand type. Soil BG activity at 10-20 cm soil layer was significantly higher in P. elliottii plantation than in P. massoniana plantation, while the activity of LAP was highest in the P. massoniana plantation. Soil BG/(NAG+LAP) and BG/AP at 10-20 cm layer of P. elliottii plantation were significantly higher than those of P. massoniana plantation, while (NAG+LAP)/AP of P. massoniana plantation was significantly higher than those of P. elliottii plantation and mixed plantation. The vector length of enzyme stoichiometry at 10-20 cm soil layer was significantly different among stand type, with an order of P. elliottii plantation > broadleaved-conifer mixed plantation > P. massoniana. The vector angles of enzyme stoichiometry in the three plantations were greater than 45°, with the vector angle in the P. elliottii plantation at 10-20 cm soil layer being significantly greater than that of the P. massoniana plantation. Results from redundancy analysis showed that soil carbon quality index and the ratio of soil organic carbon to total phosphorus (C/P), soil water content and C/P were the key factors affecting soil enzyme activity and stoichiometry at 0-10 and 10-20 cm soil layers, respectively. The quantity and quality of soil carbon and phosphorus, and soil water content played a key role in regulating nutrient cycling in mid-subtropical plantation ecosystem.

[Bmi-1-siRNA Regulates the Proliferation of K562 Leukemia Cells in vitro and in vivo by PTEN/pAKT Pathway].

OBJECTIVE: To investigate the effect of Bmi-1 gene silence on the proliferation ability of K562 cells in vitro and in vivo, and to explore the relation of molecular mechanism between proliferation ability of K562 cells in vitro and in vivo with PTEN/pAKT signaling pathway. METHODS: The Bmi-1 small interference RNA (siRNA) sequences were transfected into K562 cells for decreasing Bmi-1 expression. The effect of Bmi-1 siRNA on the proliferation of K562 cells in vitro and in vivo was detected by MTT method and colony-forming test, the effect of Bmi-1 siRNA on the tumorogenicity of K562 cells was observed by subcutaneous inoculation of K562 cells, LY294002 and Bpv treated K562 cells in nude mice, the expression of Bmi-1, PTEN and pAKT proteins were detected by Western blot. RESULTS: The Bmi-1 siRNA could inhibit the proliferation activity, colony-forming and tumor-forming abilities of K562 cells. After the silence of Bmi-1 gene, the PTEN expression in Bmi-1 gene-silenced group was significantly enhanced. While the pAKT expression in Bmi-1 gene-silenced group was significantly reduced; after the K562 cells were treated with LY294002 (an inhibitor of pAKT), the pAKT expression colony-forming and tumor forming abilities were reduced in comparison with untreated K562 cells; after the K562-S1 cells were treated with Bpv (an inhibitor of PTEN), the PTEN expression decreased, while the pAKT expression, colony forming and tumor-forming abilities were restored. CONCLUSION: The Bmi-1 gene possibly involves in regulation of K562 proliferation in vivo and in vitro, the effect of PTEN/pAKT signaling pathway maybe one of molecular mechanisms mediating this regulation.

Diterpene synthases facilitating production of the kaurane skeleton of eriocalyxin B in the medicinal plant Isodon eriocalyx.

The Isodon plants (Lamiaceae) have been used in traditional Chinese medicine to alleviate sufferings from inflammations and cancers. This feature has been attributed to the presence of pharmacologically active ent-kaurane diterpenoids such as eriocalyxin B and oridonin. The Isodon eriocalyx (Dunn) Kudô species native to southwest China can accumulate a particularly high content of ent-kaurane diterpenoids (∼1.5% w/w of dried leaves). We previously identified diterpene synthases IeCPS1 and IeCPS2 as ent-copalyl diphosphate synthases (ent-CPS) potentially involved in Isodon ent-kaurane diterpenoids biosynthesis. In this study, analysis of RNA-seq transcriptome of the I. eriocalyx plant revealed three other diterpene synthase genes (IeCPS3, IeKS1, and IeKSL1). Their functional characterization through coupled in vitro enzyme assays has confirmed that IeCPS3 is an ent-CPS specifically producing ent-copalyl diphosphate (ent-CPP). IeKS1 accepted ent-CPP to produce exclusively ent-kaurene and may thus be defined as an ent-kaurene synthase (ent-KS). When IeKSL1 was combined with IeCPS2 or IeCPS3, no product was detected. Based on tissue-specific expression and metabolic localization studies, the IeCPS3 and IeKS1 transcripts were significantly accumulated in leaves where the ent-kaurane diterpenoid eriocalyxin B dominates, whereas weak expression of both were observed in germinating seeds in which gibberellin biosynthetic pathway is normally active. Our findings suggest that both IeCPS3 and IeKS1 possess dual roles in general (gibberellins) and specialized diterpenoid metabolism, such as that of the Isodon ent-kaurane diterpenoids.

A cyanobacterial toxin, microcystin-LR, induces apoptosis of sertoli cells by changing the expression levels of apoptosis-related proteins.

Toxic cyanobacterial blooms in freshwater have been considered as threats to human health. Microcystins are a family of cyclic polypeptides produced by cyanobacteria and are toxic to plants and animals. Microcystin-LR (MC-LR) is the most toxic variant among the microcystin family and could cause oxidative stress in various organs, including the reproduction system. The aim of this study was to investigate the effect of MC-LR on apoptosis of Sertoli cells that play an essential role in the development and maturation of sperm cells. Sertoli cells were isolated from healthy immature rats and cultured with MC-LR. The viability of Sertoli cells was decreased after treatment with MC-LR at 10 µg/ml for 24 h (P < 0.05). Moreover, the MC-LR-treated cells exhibited condensed chromatin and fragmented nuclei, features of apoptosis, as judged by Hoechst 33258 staining. We also analyzed the mRNA and protein levels of three apoptosis-related genes, p53, bax and bcl-2, using reverse transcription-polymerase chain reaction and Western blot analyses, respectively. Both p53 and bax function as promoters of apoptosis, while bcl-2 is an apoptotic suppressor. The mRNA and protein expression levels of p53 and bax were increased in Sertoli cells treated with MC-LR at 10 µg/ml compared with the control group (P < 0.05), while the bcl-2 protein levels were decreased in cells treated with MC-LR at 10 µg/ml (P < 0.05). Moreover, caspase-3 activity that is involved in the induction of apoptosis was significantly increased in Sertoli cells treated with MC-LR. These results indicate that MC-LR induces apoptosis of Sertoli cells.