Dual PI3K/ERK inhibition induces necroptotic cell death of Hodgkin Lymphoma cells through IER3 downregulation

Single-Nucleus RNA Sequencing Reveals Loss of Distal Convoluted Tubule 1 Renal Tubules in HIV Viral Protein R Transgenic Mice

Although hyponatremia and salt wasting are common in patients with HIV/AIDS, the understanding of their contributing factors is limited. HIV viral protein R (Vpr) contributes to HIV-associated nephropathy. To investigate the effects of Vpr on the distal tubules and on the expression level of the Slc12a3 gene, encoding the sodium-chloride cotransporter (which is responsible for sodium reabsorption in distal nephron segments), single-nucleus RNA sequencing was performed on kidney cortices from three wild-type (WT) and three Vpr transgenic (Vpr Tg) mice. The results show that the percentage of distal convoluted tubule (DCT) cells was significantly lower in Vpr Tg mice compared with WT mice (P < 0.05); in Vpr Tg mice, Slc12a3 expression was not significantly different in DCT cells. The Pvalb+ DCT1 subcluster had fewer cells in Vpr Tg mice compared with WT mice (P < 0.01). Immunohistochemistry revealed fewer Slc12a3+Pvalb+ DCT1 segments in Vpr Tg mice. Differential gene expression analysis between Vpr Tg and WT samples in the DCT cluster showed down-regulation of the Ier3 gene, which is an inhibitor of apoptosis. The in vitro knockdown of Ier3 by siRNA transfection induced apoptosis in mouse DCT cells. These observations suggest that the salt-wasting effect of Vpr in Vpr Tg mice is likely mediated by Ier3 down-regulation in DCT1 cells and loss of Slc12a3+Pvalb+ DCT1 segments.

The lupus susceptibility allele DRB1*03:01 encodes a disease-driving epitope

The HLA-DRB1*03:01 allele is a major genetic risk factor in systemic lupus erythematosus (SLE), but the mechanistic basis of the association is unclear. Here we show that in the presence of interferon gamma (IFN-γ), a short DRB1*03:01-encoded allelic epitope activates a characteristic lupus transcriptome in mouse and human macrophages. It also triggers a cascade of SLE-associated cellular aberrations, including endoplasmic reticulum stress, unfolded protein response, mitochondrial dysfunction, necroptotic cell death, and production of pro-inflammatory cytokines. Parenteral administration of IFN-γ to naïve DRB1*03:01 transgenic mice causes increased serum levels of anti-double stranded DNA antibodies, glomerular immune complex deposition and histopathological renal changes that resemble human lupus nephritis. This study provides evidence for a noncanonical, antigen presentation-independent mechanism of HLA-disease association in SLE and could lay new foundations for our understanding of key molecular mechanisms that trigger and propagate this devastating autoimmune disease.

Development of small molecule extracellular signal-regulated kinases (ERKs) inhibitors for cancer therapy

The mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway is widely activated by a variety of extracellular stimuli, and its dysregulation is associated with the proliferation, invasion, and migration of cancer cells. ERK1/2 is located at the distal end of this pathway and rarely undergoes mutations, making it an attractive target for anticancer drug development. Currently, an increasing number of ERK1/2 inhibitors have been designed and synthesized for antitumor therapy, among which representative compounds have entered clinical trials. When ERK1/2 signal transduction is eliminated, ERK5 may provide a bypass route to rescue proliferation, and weaken the potency of ERK1/2 inhibitors. Therefore, drug research targeting ERK5 or based on the compensatory mechanism of ERK5 for ERK1/2 opens up a new way for oncotherapy. This review provides an overview of the physiological and biological functions of ERKs, focuses on the structure-activity relationships of small molecule inhibitors targeting ERKs, with a view to providing guidance for future drug design and optimization, and discusses the potential therapeutic strategies to overcome drug resistance.

KRAS and RAS-MAPK Pathway Deregulation in Mature B Cell Lymphoproliferative Disorders

KRAS mutations account for the most frequent mutations in human cancers, and are generally correlated with disease aggressiveness, poor prognosis, and poor response to therapies. KRAS is required for adult hematopoiesis and plays a key role in B cell development and mature B cell proliferation and survival, proved to be critical for B cell receptor-induced ERK pathway activation. In mature B cell neoplasms, commonly seen in adults, KRAS and RAS-MAPK pathway aberrations occur in a relevant fraction of patients, reaching high recurrence in some specific subtypes like multiple myeloma and hairy cell leukemia. As inhibitors targeting the RAS-MAPK pathway are being developed and improved, it is of outmost importance to precisely identify all subgroups of patients that could potentially benefit from their use. Herein, we review the role of KRAS and RAS-MAPK signaling in malignant hematopoiesis, focusing on mature B cell lymphoproliferative disorders. We discuss KRAS and RAS-MAPK pathway aberrations describing type, incidence, mutual exclusion with other genetic abnormalities, and association with prognosis. We review the current therapeutic strategies applied in mature B cell neoplasms to counteract RAS-MAPK signaling in pre-clinical and clinical studies, including most promising combination therapies. We finally present an overview of genetically engineered mouse models bearing KRAS and RAS-MAPK pathway aberrations in the hematopoietic compartment, which are valuable tools in the understanding of cancer biology and etiology.

Omega-Class Glutathione Transferases of Carcinogenic Liver Fluke, Clonorchis sinensis, Modulate Apoptosis and Differentiation of Host Cholangiocytes

The small liver fluke Clonorchis sinensis causes hepatobiliary ductal infections in humans. Clonorchiasis is characterized histopathologically by ductal dysplasia, hyperplasia and metaplasia, which closely resembles cholangiocarcinoma (CCA). The disruption of programmed cell death is critical for malignant transformation, while molecular events underlying these phenomena have poorly been understood in clonorchiasis-related CCA tumorigenesis. We incorporated recombinant C. sinensis omega-class glutathione transferase (rCsGSTo) 1 or 2 into human intrahepatic biliary epithelial cells (HIBECs) and analyzed pathophysiological alterations of HIBECs upon the application of oxidative stress. rCsGSTos partially but significantly rescued HIBECs from cell death by inhibiting oxidative stress-induced apoptosis (p < 0.01). rCsGSTos modulated transcriptional levels of numerous genes. We analyzed 13 genes involved in programmed cell death (the upregulation of five antiapoptotic and two apoptotic genes, and the downregulation of one antiapoptotic and five apoptotic genes) and 11 genes associated with cell differentiation (the increase in seven and decrease in four genes) that showed significant modifications (p < 0.05). The induction profiles of the mRNA and proteins of these differentially regulated genes correlated well with each other, and mostly favored apoptotic suppression and/or cell differentiation. We detected increased active, phosphorylated forms of Src, PI3K/Akt, NF-κB p65, MKK3/6 and p38 MAPK, but not JNK and ERK1/2. CsGSTos were localized in the C. sinensis-infected rat cholangiocytes, where cytokeratin 19 was distributed. Our results demonstrated that CsGSTos excreted to the biliary lumen are internalized and accumulated in the host cholangiocytes. When cholangiocytes underwent oxidative stressful condition, CsGSTos appeared to be critically involved in both antiapoptotic process and the differentiation of host cholangiocytes through the regulation of target genes following the activation of responsible signal molecules.

2-D08 treatment regulates C2C12 myoblast proliferation and differentiation via the Erk1/2 and proteasome signaling pathways

SUMOylation is one of the post-translational modifications that involves the covalent attachment of the small ubiquitin-like modifier (SUMO) to the substrate. SUMOylation regulates multiple biological processes, including myoblast proliferation, differentiation, and apoptosis. 2-D08 is a synthetically available flavone, which acts as a potent cell-permeable SUMOylation inhibitor. Its mechanism of action involves preventing the transfer of SUMO from the E2 thioester to the substrate without influencing SUMO-activating enzyme E1 (SAE-1/2) or E2 Ubc9-SUMO thioester formation. However, both the effects and mechanisms of 2-D08 on C2C12 myoblast cells remain unclear. In the present study, we found that treatment with 2-D08 inhibits C2C12 cell proliferation and differentiation. We confirmed that 2-D08 significantly hampers the viability of C2C12 cells. Additionally, it inhibited myogenic differentiation, decreasing myosin heavy chain (MHC), MyoD, and myogenin expression. Furthermore, we confirmed that 2-D08-mediated anti-myogenic effects impair myoblast differentiation and myotube formation, reducing the number of MHC-positive C2C12 cells. In addition, we found that 2-D08 induces the activation of ErK1/2 and the degradation of MyoD and myogenin in C2C12 cells. Taken together, these results indicated that 2-D08 treatment results in the deregulated proliferation and differentiation of myoblasts. However, further research is needed to investigate the long-term effects of 2-D08 on skeletal muscles.

Dietary selenomethionine ameliorates lipopolysaccharide-induced renal inflammatory injury in broilers via regulating the PI3K/AKT pathway to inhibit necroptosis

Selenomethionine (SeMet) has antioxidant and anti-inflammatory effects, as a widely used organic Se source in food supplements, and its inhibitory effect on the prevention and treatment of renal inflammatory injury is unclear. Here, in order to explore the protective effect of SeMet on kidney tissue of broilers and determine its potential molecular mechanism, we took broilers as the research object, lipopolysaccharide (LPS) was used as the source of stimulation, and the model was established by adding SeMet to the diet. The histopathological observation indicated that SeMet alleviated the LPS-induced characteristic changes of renal inflammatory injury. Besides, SeMet inhibited LPS-induced PI3K, AKT, caspase 8 and IκB-α downregulation, the necroptosis marker genes (FADD, RIP1, RIP3, MLKL and TNF-α), pro-inflammatory factors (NF-κB, PTGEs, COX-2, iNOS, IL-1β and IL-6) and HSP60, HSP70 and HSP90 overexpression. We concluded that SeMet ameliorates LPS-induced renal inflammatory injury in broilers by inhibiting necroptosis via the regulation of the PI3K/Akt pathway. Thus, we speculated that dietary SeMet may be a potential new strategy for the treatment of renal injury.

Selenium deficiency exacerbates LPS-induced necroptosis by regulating miR-16-5p targeting PI3K in chicken tracheal tissue

Multiple tissue necrosis is one of the morphological features of selenium deficiency-mediated injury. MicroRNA (miRNA) participates in the occurrence and development of necroptosis by regulating target genes. Necroptosis is a programmed form of necrosis, and it is closely related to lipopolysaccharide (LPS)-induced injury. Our aim was to investigate whether Se deficiency can promote tracheal injury caused by LPS through miRNA-induced necroptosis. By establishing models of tracheal injury in Se-deficient chickens, we verified the targeting relationship between chicken-derived miR-16-5p and PI3K through bioinformatics, qRT-PCR and WB analyses, and we measured the changes in the expression of genes related to the PI3K/AKT pathway, RIP3/MLKL pathway and MAPK pathway and of heat shock proteins. Under the condition of Se deficiency, the following results were observed: PI3K/AKT expression decreased with the upregulation of miR-16-5p, the expression of necroptosis-related factors (TNF-α, RIP1, FADD, RIP3 and MLKL) increased, and the expression of Caspase 8 significantly decreased (p < 0.05). Light microscopy observations indicated that cell necrosis was the main pathological change due to Se deficiency injury in the tracheal epithelium. The MAPK pathway was activated, and HSP expression was upregulated, indicating that the MAPK pathway and HSPs are both involved in Se deficiency-mediated necroptosis. In addition, Se deficiency promoted the expression of necroptosis-related genes in LPS-treated chickens (p < 0.05), and the pathological changes of cell necrosis were more obvious. In conclusion, we demonstrated that Se deficiency regulates the miR-16-5p-PI3K/AKT pathway and exacerbates LPS-induced necroptosis in chicken tracheal epithelial cells by activating necroptosis-related genes.

Brain-Derived Neurotrophic Factor and Its Potential Therapeutic Role in Stroke Comorbidities

With the rise in the aging global population, stroke comorbidities have become a serious health threat and a tremendous economic burden on human society. Current therapeutic strategies mainly focus on protecting neurons from cytotoxic damage at the acute phase upon stroke onset, which not only is a difficult way to ameliorate stroke symptoms but also presents a challenge for the patients to receive effective treatment in time. The brain-derived neurotrophic factor (BDNF) is the most abundant neurotrophin in the adult brain, which possesses a remarkable capability to repair brain damage. Recent promising preclinical outcomes have made BDNF a popular late-stage target in the development of novel stroke treatments. In this review, we aim to summarize the latest progress in the understanding of the cellular/molecular mechanisms underlying stroke pathogenesis, current strategies and difficulties in drug development, the mechanism of BDNF action in poststroke neurorehabilitation and neuroplasticity, and recent updates in novel therapeutic methods.

Carbon Monoxide Attenuates Lipopolysaccharides (LPS)-Induced Acute Lung Injury in Neonatal Rats via Downregulation of Cx43 to Reduce Necroptosis

Background

Acute lung injury (ALI) is one of major causes of death in newborns, making it urgent to improve therapy. Administration of low dose carbon monoxide (CO) plays a protective role in ALI but the mechanisms are not fully understood. This study was designed to test the therapeutic effect of monoxide-releasing molecule 3 (MORM3) in lipopolysaccharide (LPS) induced neonatal ALI and the possibly associated molecular mechanisms.

Material/Methods

For this study, 3- to 8-day old Newborn Sprague-Dawley rats were subjected to intraperitoneal injection of 3 mg/kg LPS to induce ALI. Then animals received intraperitoneal injection of carbon monoxide-releasing molecules 3 (CORM3) (8 mg/kg) or inactive CORM3 (iCORM3) for 7 consecutive days. Lung tissues were collected for histological examination and total cell counts and protein content in bronchoalveolar lavage fluid (BALF) were measured. Expression of Cx43 and necroptosis-related markers were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot.

Results

LPS exposure induced significant lung injury indicated by histological damage, increased lung wet/dry weight ratio (W/D) and increased total cell counts and protein concentration in BALF. These changes were significantly ameliorated by administration of CORM3 but not iCORM3. LPS also increased necroptosis-related markers RIP1, RIP3, and MLKL and their elevation was blocked by CORM3. CORM3 administration ameliorated LPS induced elevation of Cx43 expression and adenoviral overexpression of Cx43 abolished lung protective effect of CORM3. CORM3 administration attenuated LPS induced activation of extracellular-signal-regulated kinase (ERK) and its protection against necroptosis was abolished by ERK inhibitor U0126.

Conclusions

CORM3 attenuates LPS-Induced ALI in neonatal rats and its lung protective effect might be through downregulation of Cx43 to attenuate ERK signaling and ameliorate necroptosis, suggesting CORM3 as a potential therapeutic drug for ALI in neonates.

Multi-faceted computational assessment of risk and progression in oligodendroglioma implicates NOTCH and PI3K pathways

Oligodendrogliomas are diffusely infiltrative gliomas defined by IDH-mutation and co-deletion of 1p/19q. They have highly variable clinical courses, with survivals ranging from 6 months to over 20 years, but little is known regarding the pathways involved with their progression or optimal markers for stratifying risk. We utilized machine-learning approaches with genomic data from The Cancer Genome Atlas to objectively identify molecular factors associated with clinical outcomes of oligodendroglioma and extended these findings to study signaling pathways implicated in oncogenesis and clinical endpoints associated with glioma progression. Our multi-faceted computational approach uncovered key genetic alterations associated with disease progression and shorter survival in oligodendroglioma and specifically identified Notch pathway inactivation and PI3K pathway activation as the most strongly associated with MRI and pathology findings of advanced disease and poor clinical outcome. Our findings that Notch pathway inactivation and PI3K pathway activation are associated with advanced disease and survival risk will pave the way for clinically relevant markers of disease progression and therapeutic targets to improve clinical outcomes. Furthermore, our approach demonstrates the strength of machine learning and computational methods for identifying genetic events critical to disease progression in the era of big data and precision medicine.

Increased expression of immediate early response gene 3 protein promotes aggressive progression and predicts poor prognosis in human bladder cancer

Background

Immediate early response gene 3 (IER3) is a stress-inducible gene, which exerts diverse effects in regulating cell apoptosis and cell cycle. Growing evidence shows that IER3 functions either as an oncogene or a tumor suppressor in various human cancers with a cancer type-dependent manner. However, the involvement of IER3 in human bladder cancer (BCa) has not been elucidated. In the current study, we aimed to investigate the expression pattern and the clinical significance of IER3 in BCa.

Methods

We performed immunohistochemistry analysis to examine the subcellular localization and the expression levels of IER3 protein in 88 BCa specimens obtained from Department of Pathology in Massachusetts General Hospital. The associations of IER3 protein expression with various clinicopathological features and patients’ overall survival were statistically evaluated.

Results

IER3 protein was mainly expressed in the cytoplasm in bladder cancer cell. Of 88 BCa tissue specimens, 39 (44.3%) showed high expression of IER3 protein and 49 (55.7%) showed low expression. High IER3 protein expression was significantly associated with high pathologic nodal stage (p = 0.018). Kaplan-Meier analysis revealed that the overall survival of BCa patients with overexpression of IER3 protein was shorter than that with low expression (p < 0.01). Multivariate analysis by Cox regression further identified IER3 as an independent prognostic factor of BCa patients (p = 0.010).

Conclusions

Our findings suggest for the first time that the increased expression of IER3 protein may promote the aggressive progression of BCa. Importantly, IER3 may be a potential prognostic marker for BCa patients.

Electronic supplementary material

The online version of this article (10.1186/s12894-018-0388-6) contains supplementary material, which is available to authorized users.

Necrostatin-1 protects C2C12 myotubes from CoCl2-induced hypoxia

Necrostatin-1 (Nec-1) is a selective and potent allosteric inhibitor of necroptosis by specifically inhibiting the activity of receptor-interacting protein (RIP) 1 kinase. The aim of the present study was to determine the effect of Nec-1 on an anoxia model comprising mouse skeletal C2C12 myotubes. In the present study, a hypoxic mimetic reagent, cobalt chloride (CoCl₂), was used to induce hypoxia in C2C12 myotubes. The cytotoxic effects of CoCl₂-induced hypoxia were determined by a Cell Counting kit-8 assay and flow cytometry. Transmission electron microscopy (TEM) was used to characterize the morphological characteristics of dead cells at the ultrastructural level. To clarify the signaling pathways in CoCl₂-mediated cell death, the expression levels of RIP1, RIP3, extracellular signal-regulated kinase (ERK)1/2, hypoxia-inducible factor (HIF)-1α and B cell lymphoma-2 adenovirus E1B 19-kDa interacting protein 3 (BNIP3) were investigated by western blotting. Oxidative stress was determined using 2′,7′-dichlorofluorescin diacetate to measure intracellular reactive oxygen species (ROS) and the fluorescent dye JC-1 was used to measure mitochondrial membrane potential (Δψm). The results showed that the ratios of apoptotic and necrotic C2C12 cells were increased following CoCl₂ treatment, typical necroptotic morphological characteristics were able to observe by TEM, whereas Nec-1 exhibited a protective effect against CoCl₂-induced oxidative stress. Treatment with Nec-1 significantly decreased the levels of RIP1, p-ERK1/2, HIF-1α, BNIP3 and ROS induced by CoCl₂, and promoted C2C12 differentiation. Nec-1 reversed the CoCl₂-induced decrease in mitochondrial membrane potential. Together, these findings suggested that Nec-1 protected C2C12 myotubes under conditions of CoCl₂-induced hypoxia.

Signaling pathways and immune evasion mechanisms in classical Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is an unusual B-cell-derived malignancy in which rare malignant Hodgkin and Reed-Sternberg (HRS) cells are surrounded by an extensive but ineffective inflammatory/immune cell infiltrate. This striking feature suggests that malignant HRS cells escape immunosurveillance and interact with immune cells in the cancer microenvironment for survival and growth. We previously found that cHLs have a genetic basis for immune evasion: near-uniform copy number alterations of chromosome 9p24.1 and the associated PD-1 ligand loci, CD274/PD-L1 and PDCD1LG2/PD-L2, and copy number-dependent increased expression of these ligands. HRS cells expressing PD-1 ligands are thought to engage PD-1 receptor-positive immune effectors in the tumor microenvironment and induce PD-1 signaling and associated immune evasion. The genetic bases of enhanced PD-1 signaling in cHL make these tumors uniquely sensitive to PD-1 blockade.

Signaling pathways and immune evasion mechanisms in classical Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is an unusual B-cell-derived malignancy in which rare malignant Hodgkin and Reed-Sternberg (HRS) cells are surrounded by an extensive but ineffective inflammatory/immune cell infiltrate. This striking feature suggests that malignant HRS cells escape immunosurveillance and interact with immune cells in the cancer microenvironment for survival and growth. We previously found that cHLs have a genetic basis for immune evasion: near-uniform copy number alterations of chromosome 9p24.1 and the associated PD-1 ligand loci, CD274/PD-L1 and PDCD1LG2/PD-L2, and copy number-dependent increased expression of these ligands. HRS cells expressing PD-1 ligands are thought to engage PD-1 receptor-positive immune effectors in the tumor microenvironment and induce PD-1 signaling and associated immune evasion. The genetic bases of enhanced PD-1 signaling in cHL make these tumors uniquely sensitive to PD-1 blockade.