HOTAIR Promotes the Hyperactivation of PI3K/Akt and Wnt/ß-Catenin Signaling Pathways via PTEN Hypermethylation in Cervical Cancer.

The mechanisms underlying the sustained activation of the PI3K/AKT and Wnt/ß-catenin pathways mediated by HOTAIR in cervical cancer (CC) have not been extensively described. To address this knowledge gap in the literature, we explored the interactions between these pathways by driving HOTAIR expression levels in HeLa cells. Our findings reveal that HOTAIR is a key regulator in sustaining the activation of both signaling pathways. Specifically, altering HOTAIR expression-either by knockdown or overexpression-significantly influenced the transcriptional activity of the PI3K/AKT and Wnt/ß-catenin pathways. Additionally, we discovered that HIF1α directly induces HOTAIR transcription, which in turn leads to the epigenetic silencing of the PTEN promoter via DNMT1. This process leads to the sustained activation of both pathways, highlighting a novel regulatory axis involving HOTAIR and HIF1α in cervical cancer. Our results suggest a new model in which HOTAIR sustains reciprocal activation of the PI3K/AKT and Wnt/ß-catenin pathways through the HOTAIR/HIF1α axis, thereby contributing to the oncogenic phenotype of cervical cancer.

The somatic mutation profile of estrogen receptor-positive HER2-negative metastatic breast cancer in Brazilian patients.

Background: Breast cancer is the leading cause of cancer death among women worldwide. Studies about the genomic landscape of metastatic breast cancer (MBC) have predominantly originated from developed nations. There are still limited data on the molecular epidemiology of MBC in low- and middle-income countries. This study aims to evaluate the prevalence of mutations in the PI3K-AKT pathway and other actionable drivers in estrogen receptor (ER)+/HER2- MBC among Brazilian patients treated at a large institution representative of the nation's demographic diversity. Methods: We conducted a retrospective observational study using laboratory data (OC Precision Medicine). Our study included tumor samples from patients with ER+/HER2- MBC who underwent routine tumor testing from 2020 to 2023 and originated from several Brazilian centers within the Oncoclinicas network. Two distinct next-generation sequencing (NGS) assays were used: GS Focus (23 genes, covering PIK3CA, AKT1, ESR1, ERBB2, BRCA1, BRCA2, PALB2, TP53, but not PTEN) or GS 180 (180 genes, including PTEN, tumor mutation burden [TMB] and microsatellite instability [MSI]). Results: Evaluation of tumor samples from 328 patients was undertaken, mostly (75.6%) with GS Focus. Of these, 69% were primary tumors, while 31% were metastatic lesions. The prevalence of mutations in the PI3K-AKT pathway was 39.3% (95% confidence interval, 33% to 43%), distributed as 37.5% in PIK3CA and 1.8% in AKT1. Stratification by age revealed a higher incidence of mutations in this pathway among patients over 50 (44.5% vs 29.1%, p=0.01). Among the PIK3CA mutations, 78% were canonical (included in the alpelisib companion diagnostic non-NGS test), while the remaining 22% were characterized as non-canonical mutations (identifiable only by NGS test). ESR1 mutations were detected in 6.1%, exhibiting a higher frequency in metastatic samples (15.1% vs 1.3%, p=0.003). Additionally, mutations in BRCA1, BRCA2, or PALB2 were identified in 3.9% of cases, while mutations in ERBB2 were found in 2.1%. No PTEN mutations were detected, nor were TMB high or MSI cases. Conclusion: We describe the genomic landscape of Brazilian patients with ER+/HER2- MBC, in which the somatic mutation profile is comparable to what is described in the literature globally. These data are important for developing precision medicine strategies in this scenario, as well as for health systems management and research initiatives.

Tumor-suppressive action of miR-30a-5p in lung adenocarcinoma correlates with ABL2 inhibition and PI3K/AKT pathway inactivation.

INTRODUCTION: ABL2 contributes to the oncogenic potential of cancers, pointing to its inhibition as a possible strategy against malignant diseases. Bioinformatics prediction of upstream effector miR-30a-5p for ABL2 allowed us to hypothesize and then validate mechanistic actions of miR-30a-5p in lung adenocarcinoma (LUAD). MATERIALS AND METHODS: The ABL2 expression in LUAD was analyzed in the TCGA data, clinical samples, and cell lines. The shRNA-mediated silencing of ABL2 was introduced to illustrate its effect on malignant phenotypes of LUAD cells. The binding affinity between ABL2 and miR-30a-5p was verified by luciferase activity and RNA pull-down assay. Ectopic expression, knockdown methods, and PI3K inhibitor LY294002 were used to investigate their effects on in vitro biological characteristics and in vivo tumor growth of LUAD cells. Using nude mouse lung adenocarcinoma in situ and brain metastasis models to validate the inhibitory effect of miR-30a-5p on LUAD by regulating the ABL2/PI3K/AKT signaling axis. RESULTS: High expression of ABL2 and poor expression of miR-30a-5p were noticed in LUAD tissues and cell lines. Importantly, miR-30a-5p was demonstrated to target and downregulate ABL2, subsequently inactivating the PI3K/AKT pathway. miR-30a-5p inhibited the malignant phenotypes of LUAD cells by inhibiting ABL2 expression and inactivating the PI3K/AKT pathway. For in vivo experiments, miR-30a-5p was substantiated to thwart tumor tumorigenesis by regulating the ABL2/PI3K/AKT axis. In addition, miR-30a-5p suppresses the occurrence and development of in situ lung cancer and brain metastasis via the ABL2/PI3K/AKT signaling pathway. CONCLUSION: This study underscores the inhibitory role of miR-30a-5p in LUAD through the ABL2/PI3K/AKT axis, which may be a viable target for LUAD treatment.

Effects of the Natural Flavonoid Quercetin on Arenavirus Junín Infection.

There is no specific chemotherapy approved for the treatment of pathogenic arenaviruses that cause severe hemorrhagic fever (HF) in the population of endemic regions in America and Africa. The present study reports the effects of the natural flavonoid quercetin (QUER) on the infection of A549 and Vero cells with Junín virus (JUNV), agent of the Argentine HF. By infectivity assays, a very effective dose-dependent reduction of JUNV multiplication was shown by cell pretreatment at 2-6 h prior to the infection at non-cytotoxic concentrations, with 50% effective concentration values in the range of 6.1-7.5 µg/mL. QUER was also active by post-infection treatment but with minor efficacy. Mechanistic studies indicated that QUER mainly affected the early steps of virus adsorption and internalization in the multiplication cycle of JUNV. Treatment with QUER blocked the phosphorylation of Akt without changes in the total protein expression, detected by Western blot, and the consequent perturbation of the PI3K/Akt pathway was also associated with the fluorescence redistribution from membrane to cytoplasm of TfR1, the cell receptor recognized by JUNV. Then, it appears that the cellular antiviral state, induced by QUER treatment, leads to the prevention of JUNV entry into the cell.

Importância da galectina-3 na ação moduladora da crotoxina sobre função de monócito/macrófago

Crotoxin (CTX) has biological effects both in experimental models and in clinical trials. Our group showed that the antitumor activity of CTX is associated with the modulating actions of the toxin on the secretory activity of inflammatory mediators and on the energy metabolism of macrophages. Furthermore, we demonstrated that CTX, in vivo, interferes with the phenotypic reprogramming of resident peritoneal macrophages and the tumor microenvironment, suggesting a reprogramming or prevalence of the M1 phenotype of macrophages. Among the mechanisms involved with the phenotypic reprogramming of monocytes/macrophages, galectin-3 has been described as an immunoregulatory protein, which may favor the classic pro-inflammatory condition (macrophage-M1) or alternative (macrophage-M2, anti-inflammatory), depending on the pathophysiological condition, with involvement of the PI3K/Akt signaling pathway. Therefore, the objective of this project was to investigate whether CTX is capable of interfering with the expression and secretion of galectin-3 by monocytes and the participation of this lectin in the modulating activity of CTX on the phenotypic condition of these cells by different stimuli. For this purpose, in vitro assays were carried out using cells of the human monocytic lineage (THP-1), pre-incubated in the absence (control) or presence of CTX (0.3; 0.6 and 1.2 μg/mL), by 2 hours and maintained in culture for 72 hours under different microenvironmental stimuli: a) only in fresh RPMI 1640 culture medium (to evaluate the per se activity of CTX on the investigated proteins); b) with culture medium containing 800 μg/mL of LPS; or c) and conditioned medium (CM) from MDA-MB-231 tumor cells. The Western Blotting assay was performed to mark the proteins: PI3Kp110a, Akt (types 1 and 2) and galectin-3. Functional/phenotypic parameters, such as H2O2 release, secretion of pro-(TNF-α) and anti-inflammatory cytokines (IL-10/TGF-β1) and Gal-3, and phenotypic markers (M1- CD80/CD86 and M2-CD163/CD206) was determined in order to associate possible changes in the functional/phenotypic behavior (M1/M2) of these cells and with the expression of signaling proteins involved in the reprogramming of monocytes/macrophages, in the face of different stimuli. The results indicate that CTX modulates the Akt signaling pathway and with the expression and secretion of Gal-3, as well as with the release of H2O2 and against different signals in the microenvironment. Furthermore, a pro-inflammatory and pro-tumor role is attributed to Gal-3 in inflammatory and tumoral conditions and here, the results show the participation of this lectin in the immunomodulatory effect of CTX, both in the action per se of the toxin and in the inflammatory and tumoral microenvironments. Furthermore, particularly the concentration of CTX 0.6 and 1.2 μg/ml seems to promote a THP-1 mixed monocyte/macrophage profile or switch phenotype. This study contributes to knowledge about the immunomodulatory actions of CTX, showing for the first time the participation of Gal-3 in this process.

A Crotoxina (CTX) apresenta efeitos biológicos tanto em modelos experimentais como em estudos clínicos. Nosso grupo mostrou que a atividade antitumoral da CTX está associada às ações moduladoras da toxina sobre a atividade secretora de mediadores inflamatórios e sobre o metabolismo energético de macrófagos. Ainda, demonstramos que a CTX, in vivo, interfere com a reprogramação fenotípica de macrófagos peritoneais residentes e do microambiente tumoral, sugerindo uma reprogramação ou prevalência do fenótipo M1 de macrófagos. Dentre os mecanismos envolvidos com a reprogramação fenotípica de monócitos/macrófagos, a galectina-3 vem sendo descrita como uma proteína imunorreguladora, podendo favorecer a condição pró- inflamatória clássica (macrófago-M1) ou alternativa (macrófago-M2, anti-inflamatório), conforme a condição fisiopatológica, com envolvimento da via de sinalização PI3K/Akt. Portanto, o objetivo do presente projeto foi investigar se a CTX é capaz de interferir com a expressão e secreção de galectina-3 por monócitos e a participação desta lectina na atividade moduladora da CTX sobre a condição fenotípica dessas células, frente a diferentes estímulos. Para tanto, ensaios in vitro foram realizados utilizando células da linhagem monocítica humana (THP-1), pré-incubadas na ausência (controle) ou presença de CTX (0,3; 0,6 e 1,2 μg/mL), por 2 horas e mantidas em cultura por 72 horas em diferentes estímulos microambientais: a) apenas em meio de cultura RPMI 1640 fresco (para avaliar a atividade per se da CTX sobre as proteínas investigadas); b) com meio de cultura contendo 800 μg/mL de LPS; ou c) e meio condicionado de células tumorais MDA-MB-231. O ensaio de Western Blotting foi realizado para marcação das proteínas: PI3Kp110a, Akt (tipos 1 e 2) e galectina-3. Parâmetros funcionais/fenotípicos, como a liberação de H2O2, secreção de citocinas pró- (TNF-α) e anti-inflamatórias (IL-10/TGF-β1) e Gal-3 e marcadores fenotípicos (M1-CD80/CD86 e M2-CD163/CD206) foi determinado visando associar possíveis alterações sobre o comportamento funcional/fenotípico (M1/M2) dessas células e com a expressão das proteínas sinalizadoras envolvidas com a reprogramação dos monócitos/macrófagos, frente aos diferentes estímulos. Os resultados indicam que a CTX modula a via de sinalização Akt e com a expressão e secreção de Gal-3, bem como, com a liberação de H2O2 e frente a diferentes sinais no microambiente. Ainda, é atribuída a Gal-3 papel pró-inflamatória e pró-tumoral em condições inflamatória e tumoral e aqui, os resultados mostram a participação dessa lectina no efeito imunomodulador da CTX, tanto na ação per se da toxina quanto nos microambientes inflamatório e tumoral. Além disso, particularmente as concentrações de CTX 0,6 e 1,2 μg/mL parece promover um perfil misto de monócito/macrófago THP-1 ou fenótipo switch. Este estudo contribui com o conhecimento sobre as ações imunomoduladoras da CTX, evidenciando pela primeira vez a participação da Gal-3 nesse processo.

Fibronectin Modulates the Expression of miRNAs in Prostate Cancer Cell Lines.

Prostate cancer (PCa) is a significant cause of cancer-related deaths among men and companion animals, such as dogs. However, despite its high mortality and incidence rates, the molecular mechanisms underlying this disease remain to be fully elucidated. Among the many factors involved in prostate carcinogenesis, the extracellular matrix (ECM) plays a crucial role. This ECM in the prostate is composed mainly of collagen fibers, reticular fibers, elastic fibers, proteoglycans and glycoproteins, such as fibronectin. Fibronectin is a glycoprotein whose dysregulation has been implicated in the development of multiple types of cancer, and it has been associated with cell migration, invasion, and metastasis. Furthermore, our research group has previously shown that fibronectin induces transcriptional changes by modulating the expression of protein coding genes in LNCaP cells. However, potential changes at the post-transcriptional level are still not well understood. This study investigated the impact of exposure to fibronectin on the expression of a key class of regulatory RNAs, the microRNAs (miRNAs), in prostate cancer cell lines LNCaP and PC-3. Five mammalian miRNAs (miR-21, miR-29b, miR-125b, miR-221, and miR-222) were differentially expressed after fibronectin exposure in prostate cell lines. The expression profile of hundreds of mRNAs predicted to be targeted by these miRNAs was analyzed using publicly available RNA-Sequencing data (GSE64025, GSE68645, GSE29155). Also, protein-protein interaction networks and enrichment analysis were performed to gain insights into miRNA biological functions. Altogether, these functional analyzes revealed that fibronectin exposure impacts the expression of miRNAs potentially involved in PCa causing changes in critical signaling pathways such as PI3K-AKT, and response to cell division, death, proliferation, and migration. The relationship here demonstrated between fibronectin exposure and altered miRNA expression improves the comprehension of PCa in both men and other animals, such as dogs, which naturally develop prostate cancer.

EGFL7 expression profile in IDH-wildtype glioblastomas is associated with poor patient outcome.

BACKGROUND: Despite the advances in glioblastoma (GBM) treatment, the average life span of patients is 14 months. Therefore, it is urgent to identity biomarkers of prognosis, treatment response, or development of novel treatment strategies. We previously described the association of high epidermal growth factor-like domain multiple 7 (EGFL7) expression and unfavorable outcome of pilocytic astrocytoma patients. The present study aims to analyze the prognostic potential of EGFL7 in GBM isocitrate dehydrogenase (IDH)-wildtype, using immunohistochemistry and in silico approaches. METHODS: Spearman's correlation analysis of The Cancer Genome Atlas RNA sequencing data was performed. The genes strongly correlated to EGFL7 expression were submitted to enrichment gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Additionally, EGFL7 expression was associated with patient overall survival. The expression of EGFL7 was analyzed through immunohistochemistry in 74 GBM IDH-wildtype patients' samples, and was associated with clinicopathological data and overall survival. RESULTS: In silico analysis found 78 genes strongly correlated to EGFL7 expression. These genes were enriched in 40 biological processes and eight KEGG pathways, including angiogenesis/vasculogenesis, cell adhesion, and phosphoinositide 3-kinase-Akt, Notch, and Rap1 signaling pathways. The immunostaining showed high EGFL7 expression in 39 cases (52.7%). High immunolabelling was significantly associated with low Karnofsky Performance Status and poor overall survival. Cox analysis showed that GBMs IDH-wildtype with high EGFL7 expression presented a higher risk of death compared to low expression (hazard ratio, 1.645; 95% confidence interval, 1.021 to 2.650; p = .041). CONCLUSIONS: This study gives insights regarding the genes that are correlated with EGFL7, as well as biological processes and signaling pathways, which should be further investigated in order to elucidate their role in glioblastoma biology.

Neuroprotective Effects of Cholinesterase Inhibitors: Current Scenario in Therapies for Alzheimer's Disease and Future Perspectives.

Alzheimer's disease (AD) is a slowly progressive neurodegenerative disease conceptualized as a continuous process, ranging from mild cognitive impairment (MCI), to the mild, moderate, and severe clinical stages of AD dementia. AD is considered a complex multifactorial disease. Currently, the use of cholinesterase inhibitors (ChEI), such as tacrine, donepezil, rivastigmine, and galantamine, has been the main treatment for AD patients. Interestingly, there is evidence that ChEI also promotes neuroprotective effects, bringing some benefits to AD patients. The mechanisms by which the ChEI act have been investigated in AD. ChEI can modulate the PI3K/AKT pathway, which is an important signaling cascade that is capable of causing a significant functional impact on neurons by activating cell survival pathways to promote neuroprotective effects. However, there is still a huge challenge in the field of neuroprotection, but in the context of unravelling the details of the PI3K/AKT pathway, a new scenario has emerged for the development of more efficient drugs that act on multiple protein targets. Thus, the mechanisms by which ChEI can promote neuroprotective effects and prospects for the development of new drug candidates for the treatment of AD are discussed in this review.

Sunitinib induced resistance of endothelial cells by up-regulating P-glycoprotein and PI3K/Akt pathway

Abstract Drug resistance is a crucial obstacle to achieve satisfactory chemotherapeutic effects. Numerous studies have shown that the PI3K/Akt signaling pathway plays a significant role in various processes of cellular events and tumor progression, while few studies have focused on the PI3K/Akt signaling pathway in drug resistance of endothelial cells. The present study aims to explore the relationship of PI3K/Akt signaling and cellular resistance to anticancer drugs in human microvessel endothelial cells (HMEC-1). We established stable sunitinib-resiatant human microvessel endothelial cells (HMEC-su) after long-term exposure to sunitinib (a small-molecule tyrosine kinase receptor inhibitor) for 12 months. HMEC-su showed significant alternations of cell morphology and exhibited a 2.32-fold higher IC50 of sunitinib than parental HMEC-1 cells. Expression of P-glycoprotein (P-gp) and breast cancer-resistance protein (ABCG2) which mediates drug efflux, increased significantly in HMEC-su lines compared with HMEC-1 cells by western blots assay. Our study further demonstrates that LY294002 (blocking the PI3K/Akt pathway) enhances the sensibility of HMEC-su to suntinib and inhibits the gene transcription and protein expression of P-gp, ABCG2 in HMEC-su cells. In conclusion, these results indicate that LY294002 could reverse P-gp and ABCG2 mediated-drug resistance to sunitinib in HMEC-su cells by inhibiting PI3K/Akt signaling.

Polyphenols as Antitumor Agents Targeting Key Players in Cancer-Driving Signaling Pathways.

Polyphenols constitute an important group of natural products that are traditionally associated with a wide range of bioactivities. These are usually found in low concentrations in natural products and are now available in nutraceuticals or dietary supplements. A group of polyphenols that include apigenin, quercetin, curcumin, resveratrol, EGCG, and kaempferol have been shown to regulate signaling pathways that are central for cancer development, progression, and metastasis. Here, we describe novel mechanistic insights on the effect of this group of polyphenols on key elements of the signaling pathways impacting cancer. We describe the protein modifications induced by these polyphenols and their effect on the central elements of several signaling pathways including PI3K, Akt, mTOR, RAS, and MAPK and particularly those affecting the tumor suppressor p53 protein. Modifications of p53 induced by these polyphenols regulate p53 gene expression and protein levels and posttranslational modifications such as phosphorylation, acetylation, and ubiquitination that influence stability, subcellular location, activation of new transcriptional targets, and the role of p53 in response to DNA damage, apoptosis control, cell- cycle regulation, senescence, and cell fate. Thus, deep understanding of the effects that polyphenols have on these key players in cancer-driving signaling pathways will certainly lead to better designed targeted therapies, with less toxicity for cancer treatment. The scope of this review centers on the regulation of key elements of cancer signaling pathways by the most studied polyphenols and highlights the importance of a profound understanding of these regulations in order to improve cancer treatment and control with natural products.

Identification of Potential Kinase Inhibitors within the PI3K/AKT Pathway of Leishmania Species.

Leishmaniasis is a public health disease that requires the development of more effective treatments and the identification of novel molecular targets. Since blocking the PI3K/AKT pathway has been successfully studied as an effective anticancer strategy for decades, we examined whether the same approach would also be feasible in Leishmania due to their high amount and diverse set of annotated proteins. Here, we used a best reciprocal hits protocol to identify potential protein kinase homologues in an annotated human PI3K/AKT pathway. We calculated their ligandibility based on available bioactivity data of the reported homologues and modelled their 3D structures to estimate the druggability of their binding pockets. The models were used to run a virtual screening method with molecular docking. We found and studied five protein kinases in five different Leishmania species, which are AKT, CDK, AMPK, mTOR and GSK3 homologues from the studied pathways. The compounds found for different enzymes and species were analysed and suggested as starting point scaffolds for the design of inhibitors. We studied the kinases' participation in protein-protein interaction networks, and the potential deleterious effects, if inhibited, were supported with the literature. In the case of Leishmania GSK3, an inhibitor of its human counterpart, prioritized by our method, was validated in vitro to test its anti-Leishmania activity and indirectly infer the presence of the enzyme in the parasite. The analysis contributes to improving the knowledge about the presence of similar signalling pathways in Leishmania, as well as the discovery of compounds acting against any of these kinases as potential molecular targets in the parasite.

Modulation of phosphatidylinositol 3-kinase activity during in vitro oocyte maturation increases the production of bovine blastocysts.

This study aimed to evaluate the effect of regulating phosphatidylinositol 3-kinase (PI3K) activity on the kinetics of oocyte nuclear maturation and the blastocyst rate. To evaluate oocyte viability, nuclear maturation rate and in vitro embryo production, cumulus-oocyte complexes (COCs) were maintained for 0, 10 min, 6 h or 22 h in TCM 199 medium supplemented with 20 nM wortmannin, an inhibitor of PI3K. After each period, COCs were transferred to the same medium without wortmannin and kept under the same conditions until completion of 22 h of in vitro maturation (IVM). To evaluate the effect of time on progression of nuclear maturation, COCs cultivated with 20 nM wortmannin was maintained for 22, 28 or 34 h of IVM. To determine the effect of wortmannin on the activity of maturation-promoting factor (MPF), COCs were kept under IVM conditions in the presence of the inhibitor for 0, 1, 3, 6, or 8 h. Exposure of COCs to wortmannin decreased (P < 0.05) the percentage of oocytes that reached metaphase II (MII) up to 22 h, MPF activity and reduced PI3K activity by 30%. However, after 28 and 34 h, 70% of oocytes reached the MII stage in the presence of inhibitor Moreover, COCs matured in the presence of wortmannin showed an increase (P < 0.05) in the blastocyst rate. These findings suggested that the regulation of the PI3K activity during IVM of bovine COCs interfered with the meiotic progression due to control of MPF activity, positively affecting the blastocyst rate.

Involvement of lipid microdomains in human endothelial cells infected by Streptococcus agalactiae type III belonging to the hypervirulent ST-17

BACKGROUND Streptococcus agalactiae capsular type III strains are a leading cause of invasive neonatal infections. Many pathogens have developed mechanisms to escape from host defense response using the host membrane microdomain machinery. Lipid rafts play an important role in a variety of cellular functions and the benefit provided by interaction with lipid rafts can vary from one pathogen to another. OBJECTIVES This study aims to evaluate the involvement of membrane microdomains during infection of human endothelial cell by S. agalactiae. METHODS The effects of cholesterol depletion and PI3K/AKT signaling pathway activation during S. agalactiae-human umbilical vein endothelial cells (HUVEC) interaction were analysed by pre-treatment with methyl-β-cyclodextrin (MβCD) or LY294002 inhibitors, immunofluorescence and immunoblot analysis. The involvement of lipid rafts was analysed by colocalisation of bacteria with flotillin-1 and caveolin-1 using fluorescence confocal microscopy. FINDINGS In this work, we demonstrated the importance of the integrity of lipid rafts microdomains and activation of PI3K/Akt pathway during invasion of S. agalactiae strain to HUVEC cells. Our results suggest the involvement of flotillin-1 and caveolin-1 during the invasion of S. agalactiae strain in HUVEC cells. CONCLUSIONS The collection of our results suggests that lipid microdomain affects the interaction of S. agalactiae type III belonging to the hypervirulent ST-17 with HUVEC cells through PI3K/Akt signaling pathway.

miR-26a-5p protects against myocardial ischemia/reperfusion injury by regulating the PTEN/PI3K/AKT signaling pathway

Reperfusion strategies in acute myocardial infarction (AMI) can cause a series of additional clinical damage, defined as myocardial ischemia/reperfusion (I/R) injury, and thus there is a need for effective therapeutic methods to attenuate I/R injury. miR-26a-5p has been proven to be an essential regulator for biological processes in different cell types. Nevertheless, the role of miR-26a-5p in myocardial I/R injury has not yet been reported. We established an I/R injury model in vitro and in vivo. In vitro, we used cardiomyocytes to simulate I/R injury using hypoxia/reoxygenation (H/R) assay. In vivo, we used C57BL/6 mice to construct I/R injury model. The infarct area was examined by TTC staining. The level of miR-26a-5p and PTEN was determined by bioinformatics methods, qRT-PCR, and western blot. In addition, the viability and apoptosis of cardiomyocytes were separately detected by MTT and flow cytometry. The targeting relationship between miR-26a-5p and PTEN was analyzed by the TargetScan website and luciferase reporter assay. I/R and H/R treatment induced myocardial tissue injury and cardiomyocyte apoptosis, respectively. The results showed that miR-26a-5p was down-regulated in myocardial I/R injury. PTEN was found to be a direct target of miR-26a-5p. Furthermore, miR-26a-5p effectively improved viability and inhibited apoptosis in cardiomyocytes upon I/R injury by inhibiting PTEN expression to activate the PI3K/AKT signaling pathway. miR-26a-5p could protect cardiomyocytes against I/R injury by regulating the PTEN/PI3K/AKT pathway, which offers a potential approach for myocardial I/R injury treatment.

CLEC3B protects H9c2 cardiomyocytes from apoptosis caused by hypoxia via the PI3K/Akt pathway

Ischemic heart disease (IHD) is one of the leading causes of death worldwide. C-type lectin domain family 3 member B (CLEC3B) is a C-type lectin superfamily member and is reported to promote tissue remodeling. The serum levels of CLEC3B are downregulated in patients with cardiovascular disease. However, the molecular mechanisms of CLEC3B in IHD is not well-characterized. Therefore, we overexpressed CLEC3B and silenced CLEC3B in H9c2 rat cardiomyocytes for the first time. We then constructed a model of IHD in vitro through culturing H9c2 cardiomyocytes in serum-free medium under oxygen-deficit conditions. Then, Cell Counting Kit-8 (CCK-8), flow cytometry, qRT-PCR, and western blot assays were performed to investigate cell viability, apoptosis, and expression levels of CLEC3B, phosphatidylinositol 3-kinase (PI3K), phosphorylated PI3K (p-PI3K), protein kinase B (Akt), phosphorylated Akt (p-Akt), and cleaved-caspase 3. We observed that the mRNA expression of CLEC3B was decreased in hypoxic H9c2 cardiomyocytes (P<0.05). Overexpression of CLEC3B increased cell viability (P<0.01), inhibited cell apoptosis (P<0.05), upregulated the levels of p-PI3K/PI3K and p-Akt/Akt (P<0.01 or P<0.05), and downregulated expression of cleaved-caspase 3 (P<0.001) in hypoxic H9c2 cardiomyocytes while silencing of CLEC3B caused the opposite results. Inhibition of the PI3K/Akt pathway reversed the protective effect of CLEC3B on hypoxic H9c2 cardiomyocytes. Our study demonstrated that CLEC3B alleviated the injury of hypoxic H9c2 cardiomyocytes via the PI3K/Akt pathway.

Activation of PI3K/Akt pathway mediated by estrogen receptors accounts for estrone-induced vascular activation of cGMP signaling.

Estrone (E1) produces remarkable vascular effects, including relaxation, modulation of proliferation, apoptosis and cell adhesion. This study investigated the role of estrogen receptors and endothelial signaling pathways in the vascular relaxation promoted by E1. Aortic rings from male Wistar rats (250-300 g) were contracted with phenylephrine and stimulated with graded concentrations of E1. The concentration-dependent relaxation induced by E1 was abolished after removal of the endothelium or incubation with the estrogen receptor antagonist ICI 182,780. G protein-coupled estrogen receptor antagonism did not alter the E1 effect. Pretreatment of endothelium-intact arteries with inhibitors of nitric oxide synthase, guanylyl cyclase, calmodulin (CaM) and PI3K reduced the E1-induced vasorelaxation. Incubation with inhibitors of the MEK/ERK1/2 or p38MAPK pathways did not alter the E1 vasorelaxation. Similarly, inhibition of cyclooxygenase or blockade of potassium channels did not change the E1 effect. Western blot analysis evidenced that E1 induces phosphorylation of eNOS, PI3K and Akt in rat aorta. Our data demonstrate that E1 induces aortic vascular relaxation through classic estrogen receptors activation on the endothelium. We also identify CaM and PI3K/Akt pathways as critical mediators of the NO-cGMP signaling activation by E1. These findings contribute to the notion that this estrogen regulates arterial function and represents another link, besides 17ß-estradiol (E2), between postmenopause and vascular dysfunction.

Esophageal squamous cell carcinoma transcriptome reveals the effect of FOXM1 on patient outcome through novel PIK3R3 mediated activation of PI3K signaling pathway.

Esophageal squamous cell carcinoma (ESCC) presents poor prognosis, and patients diagnosed with this tumor currently lack target treatments. Therefore, in order to identify potential targets for ESCC treatment, we carried out a transcriptome analysis with ESCC and paired nonmalignant surrounding mucosa samples, followed by a master regulator analysis, and further explored the role of the identified central regulatory genes through in vivo and in vitro assays. Among the transcription factors deregulated/enriched in ESCC, we focused on FOXM1 because of its involvement in the regulation of critical biological processes. A new transcriptome analysis performed with ESCC cell lineage TE-1 showed that the modulation of FOXM1 expression resulted in PIK3R3 expression changes, whereas chromatin immunoprecipitation assay revealed that FOXM1 was capable of binding onto PIK3R3 promoter, thus demonstrating that PIK3R3 is a new FOXM1 target. Furthermore, FOXM1 overexpression resulted in the activation of PIK3/AKT signaling pathway through PIK3R3-mediated AKT phosphorylation. Finally, the analysis of the clinic-pathological data of ESCC patients revealed that overexpression of both FOXM1 and PIK3R3 was associated with poor prognosis, but only the latter was an independent prognosis factor for ESCC patients. In conclusion, our results show that FOXM1 seems to play a central role in ESCC carcinogenesis by upregulating many oncogenes found overexpressed in this tumor. Furthermore, PIK3R3 is a novel FOXM1 target that triggers the activation of the PI3K/AKT pathway in ESCC cells.

Reactive oxygen species generation mediated by NADPH oxidase and PI3K/Akt pathways contribute to invasion of Streptococcus agalactiae in human endothelial cells

BACKGROUND Streptococcus agalactiae can causes sepsis, pneumonia, and meningitis in neonates, the elderly, and immunocompromised patients. Although the virulence properties of S. agalactiae have been partially elucidated, the molecular mechanisms related to reactive oxygen species (ROS) generation in infected human endothelial cells need further investigation. OBJECTIVES This study aimed to evaluate the influence of oxidative stress in human umbilical vein endothelial cells (HUVECs) during S. agalactiae infection. METHODS ROS production during S. agalactiae-HUVEC infection was detected using the probe CM-H2DCFDA. Microfilaments labelled with phalloidin-FITC and p47phox-Alexa 546 conjugated were analysed by immunofluorescence. mRNA levels of p47phox (NADPH oxidase subunit) were assessed using Real Time qRT-PCR. The adherence and intracellular viability of S. agalactiae in HUVECs with or without pre-treatment of DPI, apocynin (NADPH oxidase inhibitors), and LY294002 (PI3K inhibitor) were evaluated by penicillin/gentamicin exclusion. Phosphorylation of p47phox and Akt activation by S. agalactiae were evaluated by immunoblotting analysis. FINDINGS Data showed increased ROS production 15 min after HUVEC infection. Real-Time qRT-PCR and western blotting performed in HUVEC infected with S. agalactiae detected alterations in mRNA levels and activation of p47phox. Pre-treatment of endothelial cells with NADPH oxidase (DPI and apocynin) and PI3K/Akt pathway (LY294002) inhibitors reduced ROS production, bacterial intracellular viability, and generation of actin stress fibres in HUVECs infected with S. agalactiae. CONCLUSIONS ROS generation via the NADPH oxidase pathway contributes to invasion of S. agalactiae in human endothelial cells accompanied by cytoskeletal reorganisation through the PI3K/Akt pathway, which provides novel evidence for the involvement of oxidative stress in S. agalactiae pathogenesis.

Ginsenoside Rg1 protects human renal tubular epithelial cells from lipopolysaccharide-induced apoptosis and inflammation damage

Ginsenoside Rg1, one of the most notable active components of Panax ginseng, has been widely reported to exert anti-inflammatory actions. This study aimed to reveal whether ginsenoside Rg1 also exhibits beneficial roles against lipopolysaccharide (LPS)-induced apoptosis and inflammation in human renal tubular epithelial cells, and to evaluate the potential role of the component on tubulointerstitial nephritis treatment. HK-2 cells were treated with various doses of ginsenoside Rg1 (0, 50, 100, 150, and 200 μM) in the absence or presence of 5 μg/mL LPS. Thereafter, CCK-8 assay, flow cytometry, western blot, migration assay, reactive oxygen species (ROS) assay, and ELISA were carried out to respectively assess cell viability, apoptosis, migration, ROS activity, and the release of inflammatory cytokines. As a result, ginsenoside Rg1 protected HK-2 cells from LPS-induced injury, as cell viability was increased, cell apoptosis was decreased, and the release of MCP-1, IL-1β, IL-6, and TNF-α was reduced. Ginsenoside Rg1 functioned to HK-2 cells in a dose-dependent manner, and the 150 μM dose exhibited the most protective functions. Ginsenoside Rg1 had no significant impact on cell migration and ROS activity, while it alleviated LPS-induced ROS release and migration impairment. Furthermore, the down-regulations of p-PI3K, p-AKT, and up-regulations of PTEN, p-IκBα, p-p65, Bcl-3 induced by LPS were recovered to some extent after ginsenoside Rg1 treatment. In conclusion, ginsenoside Rg1 protects HK-2 cells against LPS-induced inflammation and apoptosis via activation of the PI3K/AKT pathway and suppression of NF-κB pathway.

lncRNA CCAT1 promotes cell proliferation, migration, and invasion by down-regulation of miR-143 in FTC-133 thyroid carcinoma cell line

Thyroid cancer is a common malignant tumor. Long non-coding RNA colon cancer-associated transcript 1 (lncRNA CCAT1) is highly expressed in many cancers; however, the molecular mechanism of CCAT1 in thyroid cancer remains unclear. Hence, this study aimed to investigate the effect of CCAT1 on human thyroid cancer cell line FTC-133. FTC-133 cells were transfected with CCAT1 expressing vector, CCAT1 shRNA, miR-143 mimic, and miR-143 inhibitor, respectively. After different treatments, cell viability, proliferation, migration, invasion, and apoptosis were measured. Moreover, the regulatory relationship of CCAT1 and miR-143, as well as miR-143 and VEGF were tested using dual-luciferase reporter assay. The relative expressions of CCAT1, miR-143, and VEGF were tested by qRT-PCR. The expressions of apoptosis-related factors and corresponding proteins in PI3K/AKT and MAPK pathways were analyzed using western blot analysis. The results suggested that CCAT1 was up-regulated in the FTC-133 cells. CCAT1 suppression decreased FTC-133 cell viability, proliferation, migration, invasion, and miR-143 expression, while it increased apoptosis and VEGF expression. CCAT1 might act as a competing endogenous RNA (ceRNA) for miR-143. Moreover, CCAT1 activated PI3K/AKT and MAPK signaling pathways through inhibition of miR-143. This study demonstrated that CCAT1 exhibited pro-proliferative and pro-metastasis functions on FTC-133 cells and activated PI3K/AKT and MAPK signaling pathways via down-regulation of miR-143. These findings will provide a possible target for clinical treatment of thyroid cancer.