Interleukin-7 induces apoptosis of 697 pre-B cells expressing dominant-negative forms of STAT5: evidence for caspase-dependent and -independent mechanisms

Co-encapsulation of hydrophilic and hydrophobic drugs into niosomal nanocarrier for enhanced breast cancer therapy: In silico and in vitro studies

Combination therapy has been considered one of the most promising approaches for improving the therapeutic effects of anticancer drugs. This is the first study that uses two different antioxidants in full-characterized niosomal formulation and thoroughly evaluates their synergistic effects on breast cancer cells. In this study, in-silico studies of hydrophilic and hydrophobic drugs (ascorbic acid: Asc and curcumin: Cur) interactions and release were investigated and validated by a set of in vitro experiments to reveal the significant improvement in breast cancer therapy using a co-delivery approach by niosomal nanocarrier. The niosomal nanoparticles containing surfactants (Span 60 and Tween 60) and cholesterol at 2:1 M ratio were prepared through the film hydration method. A systematic evaluation of nanoniosomes was carried out. The release profile demonstrated two phases (initial burst followed by sustained release) and a pH-dependent release schedule over 72 h. The optimized niosomal preparation displayed superior storage stability for up to 2 months at 4 °C, exhibiting extremely minor changes in pharmaceutical encapsulation efficiency and size. Free dual drugs (Asc + Cur) and dual-drug loaded niosomes (Niosomal (Asc + Cur)) enhanced the apoptotic activity and cytotoxicity and inhibited cell migration which confirmed the synergistic effect of co-encapsulated drugs. Also, significant up-regulation of p53 and Bax genes was observed in cells treated with Asc + Cur and Niosomal (Asc + Cur), while the anti-apoptotic Bcl-2 gene was down-regulated. These results were in correlation with the increase in the enzyme activity of SOD, CAT, and caspase, and the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) upon treatment with the mentioned drugs. Furthermore, these anti-cancer effects were higher when using Niosomal (Asc + Cur) than Asc + Cur. Histopathological examination also revealed that Niosomal (Asc + Cur) had a lower mitosis index, invasion, and pleomorphism than Asc + Cur. These findings indicated that niosomal formulation for co-delivery of Asc and Cur would offer a promising delivery system for an effective breast cancer treatment.

Characterization of Japanese flounder (Paralichthys olivaceus) STAT members: An immune-related gene family involved in Edwardsiella tarda and temperature stress

The signal transducer and activator of transcription (STAT) family members are not only the transcriptional activators, but also play important roles in regulating inflammatory response. Some members have been reported to be involved in innate bacterial and antiviral immunity in aquatic organisms. However, no systematic research on STATs has been found in teleost. In this present study, we characterized six STAT genes in Japanese flounder based on bioinformatics methods, namely PoSTAT1, PoSTAT2, PoSTAT3, PoSTAT4, PoSTAT5 and PoSTAT6. The phylogenetic analysis of STATs in fish indicated that STATs were highly conserved and revealed an absence of STAT5 in a few species. Further analysis of gene structures and motifs showed STAT proteins shared a similar structure and probably had similar functionality in Japanese flounder. The expression profiles of different development stages and tissues demonstrated that PoSTATs exhibited specificity in temporality and spatiality as well as PoSTAT4 was highly expressed in gill. The transcriptome data analysis of E. tarda and temperature stress showed that PoSTAT1 and PoSTAT2 were more respective to these two kinds of stress. In addition, the results also demonstrated that these PoSTATs might regulate immune response in different ways, manifested by up-regulation in E. tarda infection and down-regulation in temperature stress. In a word, this systematic analysis of PoSTATs would provide valuable information about the phylogenetic relationship of STATs in fish species and help understand the role of STAT genes in the immune response of Japanese flounder.

Developmental Toxicity of Surface-Modified Gold Nanorods in the Zebrafish Model

BACKGROUND

nanotechnology is one of the fastest-growing areas, and it is expected to have a substantial economic and social impact in the upcoming years. Gold particles (AuNPs) offer an opportunity for wide-ranging applications in diverse fields such as biomedicine, catalysis, and electronics, making them the focus of great attention and in parallel necessitating a thorough evaluation of their risk for humans and ecosystems. Accordingly, this study aims to evaluate the acute and developmental toxicity of surface-modified gold nanorods (AuNRs), on zebrafish (Danio rerio) early life stages.

METHODS

in this study, zebrafish embryos were exposed to surface-modified AuNRs at concentrations ranging from 1 to 20 μg/mL. Lethality and developmental endpoints such as hatching, tail flicking, and developmental delays were assessed until 96 h post-fertilization (hpf).

RESULTS

we found that AuNR treatment decreases the survival rate in embryos in a dose-dependent manner. Our data showed that AuNRs caused mortality with a calculated LC50 of EC_50,24hpf of AuNRs being 9.1 μg/mL, while a higher concentration of AuNRs was revealed to elicit developmental abnormalities. Moreover, exposure to high concentrations of the nanorods significantly decreased locomotion compared to untreated embryos and caused a decrease in all tested parameters for cardiac output and blood flow analyses, leading to significantly elevated expression levels of cardiac failure markers ANP/NPPA and BNP/NPPB.

CONCLUSIONS

our results revealed that AuNR treatment at the EC₅₀ induces apoptosis significantly through the P53, BAX/BCL-2, and CASPASE pathways as a suggested mechanism of action and toxicity modality.

The Functional Properties of Preserved Eggs: From Anti-cancer and Anti-inflammatory Aspects

Preserved egg, a kind of alkaline-fermented food, is a traditional egg product in China. Here, we investigated the nutritional functions of preserved eggs by in vivo and in vitro experiments. The results of in vivo studies showed that the levels of triglycerides (TG), total cholesterol (TCHO) and low-density lipoprotein cholesterol/high density lipoprotein cholesterol (LDL-C/HDL-C) were significantly decreased (p<0.05) in the liver of rats treated with preserved eggs. Meanwhile, the levels of two important cancer markers, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), were also significantly decreased (p<0.05) in treated rats. In vitro studies were performed on Caco-2 cells, a human epithelial colorectal adenocarcinoma cell line. It demonstrated that the gastrointestinal (GI) digests of preserved eggs significantly accelerated (p<0.05) the apoptosis by upregulating caspase-3 in the Caco-2 cells. Besides, after treated with preserved eggs, the half maximal inhibitory concentration (IC50) of preserved eggs digests to Caco-2 cells was 5.75 mg/mL, indicating the significant inhibition of cell proliferation provided by preserved eggs (p<0.05). The results shown in this study demonstrated that preserved eggs may be a novel functional food involved with antilipemic, anti-inflammatory activity as well as the effect on accelarating the apoptosis of Caco-2 cells.

Antitumor effect and mechanism of an ellagic acid derivative on the HepG2 human hepatocellular carcinoma cell line

In the present study, to identify the effective components of Chinese traditional herbs, Euphorbia hylonoma Hand.-Mazz. (Euphorbiaceae), a folk herb that has been used among the Qinling mountain area for hundreds of years, was investigated. 3,3′-Di-O-methyl ellagic acid-4′-O-β-d-xylopyranoside (JNE2), an ellagic acid derivative, was isolated from the acetone extract of the herb and its antitumor activity against human hepatoma HepG2 cells was detected in vitro. The results showed that JNE2 inhibited the proliferation of HepG2 cells in a dose- and time-dependent manner and blocked the cell cycle at the G1/S phase. A high dosage of JNE2 induced apoptosis of the tumor cells, but no significant differences were identified between the treatment groups. The invasiveness of HepG2 cells was also inhibited by JNE2. The mechanism of the antitumor effect of JNE2 at the molecular level was presumed to be due to the upregulation of the protein expression of Bax and caspase-3, and the downregulation of the protein expression of Bcl-2 and CCND1. The results suggested that JNE2 is a potential antitumor agent that merits further investigation.

Identification of a STAT5 target gene, Dpf3, provides novel insights in chronic lymphocytic leukemia

STAT5 controls essential cellular functions and is encoded by two genes, Stat5a and Stat5b. To provide insight to the mechanisms linking hematologic malignancy to STAT5 activation/regulation of target genes, we identified STAT5 target genes and focused on Dpf3 gene, which encodes for an epigenetic factor. Dpf3 expression was induced upon IL-3 stimulation in Ba/F3 cells, while strong binding of both STAT5a and STAT5b was detected in its promoter. Reduced expression of Dpf3 was detected in Ba/F3 cells with Stat5a and Stat5b knock-down, suggesting that this gene is positively regulated by STAT5, upon IL-3 stimulation. Furthermore, this gene was significantly up-regulated in CLL patients, where DPF3 gene/protein up-regulation and strong STAT5 binding to the DPF3 promoter, correlated with increased STAT5 activation, mainly in non-malignant myeloid cells (granulocytes). Our findings provide insights in the STAT5 dependent transcriptional regulation of Dpf3, and demonstrate for the first time increased STAT5 activation in granulocytes of CLL patients. Novel routes of investigation are opened to facilitate the understanding of the role of STAT5 activation in the communication between non-malignant myeloid and malignant B-cells, and the functions of STAT5 target genes networks in CLL biology.

In vitro delivery and controlled release of Doxorubicin for targeting osteosarcoma bone cancer

Drug delivery systems are designed to achieve drug therapeutic index and enhance the efficacy of controlled drug release targeting with specificity and selectivity by successful delivery of therapeutic agents at the desired sites without affecting the non-diseased neighbouring cells or tissues. In this research, we developed and demonstrated a bio-based calcium carbonate nanocrystals carrier that can be loaded with anticancer drug and selectively deliver it to cancer cells with high specificity by achieving the effective osteosarcoma cancer cell death without inducing specific toxicity. The results showed pH sensitivity of the controlled release characteristics of the drug at normal physiological pH 7.4 with approximately 80% released within 1,200 min but when exposed pH 4.8 the corresponding 80% was released in 50 min. This study showed that the DOX-loaded CaCO₃ nanocrystals have promising applications in delivery of anticancer drugs.

Evidence for a protective role of the STAT5 transcription factor against oxidative stress in human leukemic pre-B cells

STAT5 transcription factors are involved in normal B lymphocyte development and in leukemogenesis. We show that the inhibition of STAT5A expression or activity in the NALM6, 697 and Reh leukemic pre-B cell lines, results in a higher spontaneous apoptosis and an increased FAS-induced cell death. However, the molecular mechanisms underlying the altered pre-B cell survival are unclear. We used a proteomic approach to identify proteins that are differentially regulated in cells expressing (NALM6Δ5A) or not a dominant negative form of STAT5A. Among the 14 proteins identified, six were involved in the control of the oxidative stress like glutathione (GSH) synthetase and DJ-1. Accordingly, we showed increased levels of reactive oxygen species (ROS) in NALM6Δ5A cells and suppression of the increased sensitivity to Fas-mediated apoptosis by the GSH tripeptide. Similar results were observed when NALM6 cells were treated with TAT-STAT5Δ5A fusion proteins or STAT5A shRNA. In addition, the 697 and Reh pre-B cells were found to share number of molecular changes observed in NALM6Δ5A cells including ROS generation, following inhibition of STAT5 expression or function. Our results point out to a hitherto undescribed link between STAT5 and oxidative stress and provide new insights into STAT5 functions and their roles in leukemogenesis.

The tumor suppressor hTid1 inhibits STAT5b activity via functional interaction

STAT5a and -5b (signal transducers and activators of transcription 5a and 5b) proteins play an essential role in hematopoietic cell proliferation and survival and are frequently constitutively active in hematologic neoplasms and solid tumors. Because STAT5a and STAT5b differ mainly in the carboxyl-terminal transactivation domain, we sought to identify new proteins that bind specifically to this domain by using a bacterial two-hybrid screening. We isolated hTid1, a human DnaJ protein that acts as a tumor suppressor in various solid tumors. hTid1 interacts specifically with STAT5b but not with STAT5a in hematopoietic cell lines. This interaction involves the cysteine-rich region of the hTid1 DnaJ domain. We also demonstrated that hTid1 negatively regulates the expression and transcriptional activity of STAT5b and suppresses the growth of hematopoietic cells transformed by an oncogenic form of STAT5b. Our findings define hTid1 as a novel partner and negative regulator of STAT5b.

Exogenous phosphatidylethanolamine induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway

AIM: To investigate the signaling pathways implicated in phosphatidylethanolamine (PE)-induced apoptosis of human hepatoma HepG2 cells.

METHODS: Inhibitory effects of PE on human hepatoma HepG2 cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle, apoptosis and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry. Immunocytochemical assay and Western blotting were used to examine Bcl-2, Bax and caspase-3 protein levels in HepG2 cells treated with PE.

RESULTS: PE inhibited the growth of HepG2 cells in a dose- and time- dependent manner. It did not affect the cell cycle, but induced apoptosis. PE significantly decreased δΨm at 0.25, 0.5 and 1 mmol/L, respectively, suggesting that PE induces cell apoptosis by decreasing the mitochondrial transmembrane potential. The Bcl-2 expression level induced by different concentrations of PE was lower than that in control groups. However, the Bax expression level induced by PE was higher than that in the control group. Meanwhile, PE increased the caspase-3 expression in a dose- and time-dependent manner.

CONCLUSION: Exogenous PE induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway.

Signal transducer and activator of transcription signals in allergic disease

Signal transducer and activator of transcription (STAT) proteins are a group of transcription factors that transmit signals from the extracellular milieu of cells to the nucleus. They are crucial for the signaling of many cytokines that are mediators of allergic inflammation and impact various cell types critical to allergy including epithelial cells, mast cells, lymphocytes, dendritic cells, and eosinophils. Dysregulation of STAT signaling has been implicated in allergic disease, highlighting the importance of these ubiquitous molecules in allergic inflammation and the potential of these pathways as a target for therapeutic intervention. This review will summarize the current understanding of the roles of STAT signaling in allergic disease and the potential of targeting STATs for the treatment of allergic disorders, emphasizing recent observations.

Activated STAT5 proteins induce activation of the PI 3-kinase/Akt and Ras/MAPK pathways via the Gab2 scaffolding adapter

The active forms of STAT5A (signal transducer and activator of transcription 5A) and STAT5B are able to relieve the cytokine dependence of haematopoietic cells and to induce leukaemia in mice. We have demonstrated previously that activation of the PI3K (phosphoinositide 3-kinase) signalling cascade plays a major role in cell growth and survival induced by these proteins. Interaction between STAT5 and p85, the regulatory subunit of the PI3K, has been suggested to be required for this activation. We show in the present study that the scaffolding protein Gab2 [Grb2 (growth-factor-receptor-bound protein 2)-associated binder-2] is an essential component of this interaction. Gab2 is persistently tyrosine-phosphorylated in Ba/F3 cells expressing caSTAT5 (constitutively activated STAT5), independent of JAK2 (Janus kinase 2) activation where it interacts with STAT5, p85 and Grb2, but not with Shp2 [SH2 (Src homology 2)-domain-containing tyrosine phosphatase] proteins. Interaction of STAT5 with Gab2 was also observed in Ba/F3 cells stimulated with interleukin-3 or expressing the oncogenic fusion protein Tel-JAK2. The MAPKs (mitogen-activated protein kinases) ERK1 (extracellular-signal-regulated kinase 1) and ERK2 were constitutively activated in the caSTAT5-expressing cells and were found to be required for caSTAT5-induced cell proliferation. Overexpression of Gab2-3YF, a mutant of Gab2 incapable of binding PI3K, inhibited the proliferation and survival of caSTAT5-expressing cells as well as ERK1/2 and Akt/protein kinase B phosphorylation. Taken together, our results indicate that Gab2 is required for caSTAT5-induced cell proliferation by regulating both the PI3K/Akt and the Ras/MAPK pathways.

Voltage-gated K+ current: a marker for apoptosis in differentiating neuronal progenitor cells?

We investigated apoptosis during early stages of in vitro differentiation of neuronal precursors generated by embryonic day 14 (E14) mouse striata stem cells. Differentiation was in conditions of suboptimal growth factor supply. Apoptosis reached 10-15% of cells and affected proliferating as well as postmitotic cells, including TUJ1-positive cells. Inhibition of apoptosis led to an increased proportion of TUJ1-positive cells generated by stem cells. K(+) current was reported to be related to apoptosis. Outward K(+) currents were present in differentiating neuronal precursors that were consistent with delayed rectifier and transient A-type currents. The amplitude of the delayed rectifier current varied during the first 4 days of stem cell differentiation. Current amplitude was greatly increased in the presence of staurosporine but reduced at elevated extracellular K(+) concentration. In addition, the amplitude of the current was significantly diminished by inhibiting several caspases, but not caspase 8. In Bax knock-out transgenic neuronal precursors, K(+) current was not decreased after the first day but at later stages of cell differentiation. At this early stage, apoptosis of proliferating cells and of TUJ1-positive cells was not reduced by the absence of Bax, but was by caspase 9 inhibition. Thus, activation of a delayed rectifier K(+) current in differentiating stem cells is related to apoptosis. Recordings of this current revealed that apoptosis at early stages of neuronal differentiation occurred in two phases that did not exhibit similar dependence on the proapoptotic protein Bax and that probably used different pathways.