CRISPR-Cas12 and Cas13: the lesser known siblings of CRISPR-Cas9


Genome-wide off-targets of drugs: risks and opportunities


Trichloroethylene-induced downregulation of miR-199b-5p contributes to SET-mediated apoptosis in hepatocytes

Abstract

Trichloroethylene (TCE) is a ubiquitous toxicant widespread in our environment. Exposure to TCE can cause severe liver damage. In previous studies, we detected an abnormal elevation of SET (a protein encoded by the SETgene in humans) which was observed in human HL-7702 cells (L-02 hepatocytes) under the treatment of TCE. Moreover, further study indicated that SET acts as an important mediator in TCE-induced hepatocyte apoptosis. The major functions of SET have been elucidated, while the regulatory mechanism responsible for modulation of SET remains unclear. In this study, four major microRNA-related databases were used to screen and identify 6 candidate microRNAs involved in the regulation of SET. Subsequent verification indicated that miR-21 and miR-199b-5p were decreased in TCE-treated L-02 cells, suggesting that miR-21 and miR-199b-5p (miR199b for short) miR199b potentially regulate SET expression. Additionally, the dual-luciferase system revealed that only miR199b could directly bind to untranslated region (3′-UTR) of the SETgene. Modulation of SET by miR199b was verified through overexpression and knockdown of miR199b in L-02 cells. Assessment of apoptosis indicated that elevated miR199b attenuated TCE-induced apoptosis, while reduced miR199b enhanced it. In summary, this study suggests that in cultured hepatocytes, TCE-induced suppression of miR199b drives SET induction, which further mediates the response to TCE.

The sodium pump α1 subunit regulates bufalin sensitivity of human glioblastoma cells through the p53 signaling pathway

Abstract

Bufalin is the primary component of the traditional Chinese medicine “Chan Su,” which has been widely used for cancer treatment at oncology clinics in certain countries. Evidence suggests that this compound possesses potent antitumor activities, although the exact molecular mechanism(s) require further elucidation. Therefore, this study aimed to further clarify the in vitro and in vivo antiglioma effects of bufalin and the molecular mechanism underlying the regulation of drug sensitivity. The anticancer effects of bufalin were determined by colony formation assays, apoptosis assays, and cellular redox state tests of glioma cells. Confocal microscopy was performed to determine the expression changes of the DNA damage biomarker γ-H2AX and the nuclear translocation of p53 in glioma cells. Western blotting and RT-PCR were used to detect the protein and gene expression levels, respectively. Here, we report that bufalin induced glioblastoma cell apoptosis and oxidative stress and triggered DNA damage. The critical roles of the sodium pump α1 subunit (ATP1A1) in mediating the XPO1-targeted anticancer effect of bufalin in human glioma were further confirmed. Mechanistic studies confirmed the important roles of Src and p53 signaling in mediating bufalin-induced apoptosis. Importantly, bufalin also inhibited the growth of glioma xenografts. In conclusion, our study indicated that therapies targeting the ATP1A1 and p53 signaling-mediated mitochondrial apoptotic pathways regulated by bufalin might be potential treatments for human glioma, and these findings will provide molecular bases for developing bufalin into a drug candidate for the treatment of malignant glioma.

Relevance of Erk1/2-PI3K/Akt signaling pathway in CEES-induced oxidative stress regulates inflammation and apoptosis in keratinocytes

Abstract

2-Chloroethyl ethyl sulfide (CEES) is a well-known chemical warfare agent that induces cellular stress in exposed individuals. However, molecular mechanisms of CEES-induced oxidative stress–mediated metabolic deregulation are not clearly elucidated. Here we investigated CEES-induced free radical production act as key functional mediators of metabolic stress via Erk1/2 mitogen–activated protein kinases (MAPKs) and phosphatidylinositol-3-kinase (PI3K/Akt) signaling cascades in keratinocytes. We observed that CEES exposure disrupts the cellular antioxidant defense capacities leading to increase in free oxygen and nitrogen radical accumulation in keratinocytes. These unusual cellular abnormalities initiate cellular stress via Erk1/2-PI3K/Akt signaling pathways. Biochemical tools were used to analyze the changes in metabolites including sulfur amino acids (SAAs), namely, l-glutathione (GSH) and l-cysteine (Cys), in the presence of selective inhibitors of reactive oxygen/nitrogen species (ROS/RNS), Erk1/2, or PI3K/Akt after CEES exposure. Importantly, these metabolite changes were accompanied by a decrease in the glycolytic flux, consistent with the observed decrease in 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2) concentration and these CEES-induced phenomena were attenuated by pretreatment of Erk1/2 or PI3-K/Akt inhibitors. On the other hand, CEES exposure disrupts the protein carbonylation (PC) and lipid peroxidation (LPO) in keratinocytes leading to inflammation, crash of the cell–cell communication, cell cycle deregulation, and apoptosis via Erk1/2-PI3K/Akt pathways. However, pretreatment of Erk1/2 or PI3K/Akt inhibitors attenuated the CEES action. Collectively, these results illustrated that accumulated free radicals act as key functional mediators for inflammation, and apoptosis via Erk1/2-PI3K/Akt regulatory signaling cascades induced by CEES exposure. Treatment of pharmacological Erk1/2-PI3K/Akt inhibitors attenuated the CEES-induced keratinocyte injury that may provide the basis for the development of therapeutic strategy to work against CEES exposure.

Peroxiredoxin 4 ameliorates amyloid beta oligomer-mediated apoptosis by inhibiting ER-stress in HT-22 hippocampal neuron cells

Abstract

Alzheimer’s disease (AD) is a neurodegenerative disorder caused by amyloid beta oligomers (AβO), which induce cell death by triggering oxidative stress and endoplasmic reticulum (ER) stress. Oxidative stress is regulated by antioxidant enzymes, including peroxiredoxins. Peroxiredoxins (Prx) are classified into six subtypes, based on their localization and cysteine residues, and protect cells by scavenging hydrogen peroxide (H₂O₂). Peroxiredoxin 4 (Prx4) is unique in being localized to the ER; however, whether Prx4 protects neuronal cells from AβO-induced toxicity remains unclear, although Prx4 expression is upregulated in AβO-induced oxidative stress and ER stress. In this study, we established HT-22 cells in which Prx4 was either overexpressed or silenced to investigate its role in AβO-induced toxicity. AβO-stimulation of HT-22 cells with overexpressed Prx4 caused decreases in both AβO-induced ROS and ER stress (followed by ER expansion). In contrast, AβO stimulation caused increases in both ROS and ER stress that were notably higher in HT-22 cells with silenced Prx4 expression than in HT-22 cells. Consequently, Prx4 overexpression decreased apoptotic cell death and ameliorated the AβO-induced increase in intracellular Ca²⁺. Therefore, we conclude that Prx4 has a protective effect against AβO-mediated oxidative stress, ER stress, and neuronal cell death. Furthermore, these results suggest that Prx4 may be a target for preventing AβO toxicity in AD.

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A new pyridazinone exhibits potent cytotoxicity on human cancer cells via apoptosis and poly-ubiquitinated protein accumulation

Abstract

In the last 15 years, pyridazinone derivatives have acquired extensive attention due to their widespread biological activities and pharmacological applications. Pyridazinones are well known for their anti-microbial, anti-viral, anti-inflammatory, anti-cancer, and cardiovascular activities, among others. In this study, we evaluated the anti-cancer activity of a new pyridazinone derivative and propose it as a potential anti-neoplastic agent in acute promyelocytic leukemia cells. Pyr-1 cytotoxicity was assessed on several human cancer and two non-cancerous cell lines by the DNS assay. Pyr-1 demonstrated potent cytotoxicity against 22 human cancer cell lines, exhibiting the most favorable selective cytotoxicity on leukemia (CEM and HL-60), breast (MDA-MB-231 and MDA-MB-468), and lung (A-549) cancer cell lines, when compared with non-cancerous breast epithelial MCF-10A cells. Analyses of apoptosis/necrosis pathways, reactive oxygen species (ROS) production, mitochondria health, caspase-3 activation, and cell cycle profile were performed via flow cytometry. Both hmox-1 RNA and protein expression levels were evaluated by quantitative real-time PCR and Western blotting assays, respectively. Pyr-1 induced apoptosis in acute promyelocytic leukemia cells as confirmed by phosphatidylserine externalization, mitochondrial depolarization, caspase-3 activation, DNA fragmentation, and disrupted cell cycle progression. Additionally, it was determined that Pyr-1 generates oxidative and proteotoxic stress by provoking the accumulation of ROS, resulting in the overexpression of the stress-related hmox-1 mRNA transcripts and protein and a marked increase in poly-ubiquitinated proteins. Our data demonstrate that Pyr-1 induces cell death via the intrinsic apoptosis pathway by accumulating ROS and by impairing proteasome activity.

Mitochondrial dysfunction and chronic lung disease

Abstract

The functions of body gradually decrease as the age increases, leading to a higher frequency of incidence of age-related diseases. Diseases associated with aging in the respiratory system include chronic obstructive pulmonary disease (COPD), IPF (idiopathic pulmonary fibrosis), asthma, lung cancer, and so on. The mitochondrial dysfunction is not only a sign of aging, but also is a disease trigger. This article aims to explain mitochondrial dysfunction as an aging marker, and its role in aging diseases of lung. We also discuss whether the mitochondria can be used as a target for the treatment of aging lung disease.

Long-term treatment with arsenite activates HER1 and HER2 through upregulating EGF, TGFα, and HSP90 in a human uroepithelial cell line