Presenilin1 exerts antiproliferative effects by repressing the Wnt/β-catenin pathway in glioblastoma

Yttrium oxide nanoparticles ameliorates calcium hydroxide and calcium titanate nanoparticles induced genomic DNA and mitochondrial damage, ROS generation and inflammation

Calcium hydroxide (Ca(OH)2NPs), calcium titanate (CaTiO3NPs) and yttrium oxide (Y2O3NPs) nanoparticles are prevalent in many industries, including food and medicine, but their small size raises concerns about potential cellular damage and genotoxic effects. However, there are very limited studies available on their genotoxic effects. Hence, this was done to investigate the effects of multiple administration of Ca(OH)2NPs, CaTiO3NPs or/and Y2O3NPs on genomic DNA stability, mitochondrial membrane potential integrity and inflammation induction in mouse brain tissues. Mice were orally administered Ca(OH)2NPs, CaTiO3NPs or/and Y2O3NPs at a dose level of 50 mg/kg b.w three times a week for 2 weeks. Genomic DNA integrity was studied using Comet assay and the level of reactive oxygen species (ROS) within brain cells was analyzed using 2,7 dichlorofluorescein diacetate dye. The expression level of Presenilin-1, tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6) genes and the integrity of the mitochondrial membrane potential were also detected. Oral administration of Ca(OH)2NPs caused the highest damage to genomic DNA and mitochondrial membrane potential, less genomic DNA and mitochondrial damage was induced by CaTiO3NPs administration while administration of Y2O3NPs did not cause any remarkable change in the integrity of genomic DNA and mitochondrial membrane potential. Highest ROS generation and upregulation of presenilin-1, TNF-α and IL-6 genes were also observed within the brain cells of mice administrated Ca(OH)2NPs but Y2O3NPs administration almost caused no changes in ROS generation and genes expression compared to the negative control. Administration of CaTiO3NPs alone slightly increased ROS generation and the expression level of TNF-α and IL-6 genes. Moreover, no remarkable changes in the integrity of genomic DNA and mitochondrial DNA potential, ROS level and the expression level of presenilin-1, TNF-α and IL-6 genes were noticed after simultaneous coadministration of Y2O3NPs with Ca(OH)2NPs and CaTiO3NPs. Coadministration of Y2O3NPs with Ca(OH)2NPs and CaTiO3NPs mitigated Ca(OH)2NPs and CaTiO3NPs induced ROS generation, genomic DNA damage and inflammation along with restoring the integrity of mitochondrial membrane potential through Y2O3NPs scavenging free radicals ability. Therefore, further studies are recommended to study the possibility of using Y2O3NPs to alleviate Ca(OH)2NPs and CaTiO3NPs induced genotoxic effects.

Muscle Psn gene combined with exercise contribute to healthy aging of skeletal muscle and lifespan by adaptively regulating Sirt1/PGC-1α and arm pathway

The Presenilin (Psn) gene is closely related to aging, but it is still unclear the role of Psn genes in skeletal muscle. Here, the Psn-UAS/Mhc-GAL4 system in Drosophila was used to regulate muscle Psn overexpression(MPO) and muscle Psn knockdown(MPK). Drosophila were subjected to endurance exercise from 4 weeks to 5 weeks old. The results showed that MPO and exercise significantly increased climbing speed, climbing endurance, lifespan, muscle SOD activity, Psn expression, Sirt1 expression, PGC-1α expression, and armadillo (arm) expression in aged Drosophila, and they significantly decreased muscle malondialdehyde levels. Interestingly, when the Psn gene is knockdown by 0.78 times, the PGC-1α expression and arm expression were also down-regulated, but the exercise capacity and lifespan were increased. Furthermore, exercise combined with MPO further improved the exercise capacity and lifespan. MPK combined with exercise further improves the exercise capacity and lifespan. Thus, current results confirmed that the muscle Psn gene was a vital gene that contributed to the healthy aging of skeletal muscle since whether it was overexpressed or knocked down, the aging progress of skeletal muscle structure and function was slowed down by regulating the activity homeostasis of Sirt1/PGC-1α pathway and Psn/arm pathway. Exercise enhanced the function of the Psn gene to delay skeletal muscle aging by up regulating the activity of the Sirt1/PGC-1α pathway and Psn/arm pathway.

Alzheimer's disease: The role of proteins in formation, mechanisms, and new therapeutic approaches

Alzheimer's disease (AD) is a progressive neurological disorder that affects the central nervous system (CNS), leading to memory and cognitive decline. In AD, the brain experiences three main structural changes: a significant decrease in the quantity of neurons, the development of neurofibrillary tangles (NFT) composed of hyperphosphorylated tau protein, and the formation of amyloid beta (Aβ) or senile plaques, which are protein deposits found outside cells and surrounded by dystrophic neurites. Genetic studies have identified four genes associated with autosomal dominant or familial early-onset AD (FAD): amyloid precursor protein (APP), presenilin 1 (PS1), presenilin 2 (PS2), and apolipoprotein E (ApoE). The formation of plaques primarily involves the accumulation of Aβ, which can be influenced by mutations in APP, PS1, PS2, or ApoE genes. Mutations in the APP and presenilin (PS) proteins can cause an increased amyloid β peptides production, especially the further form of amyloidogenic known as Aβ42. Apart from genetic factors, environmental factors such as cytokines and neurotoxins may also have a significant impact on the development and progression of AD by influencing the formation of amyloid plaques and intracellular tangles. Exploring the causes and implications of protein aggregation in the brain could lead to innovative therapeutic approaches. Some promising therapy strategies that have reached the clinical stage include using acetylcholinesterase inhibitors, estrogen, nonsteroidal anti-inflammatory drugs (NSAIDs), antioxidants, and antiapoptotic agents. The most hopeful therapeutic strategies involve inhibiting activity of secretase and preventing the β-amyloid oligomers and fibrils formation, which are associated with the β-amyloid fibrils accumulation in AD. Additionally, immunotherapy development holds promise as a progressive therapeutic approach for treatment of AD. Recently, the two primary categories of brain stimulation techniques that have been studied for the treatment of AD are invasive brain stimulation (IBS) and non-invasive brain stimulation (NIBS). In this article, the amyloid proteins that play a significant role in the AD formation, the mechanism of disease formation as well as new drugs utilized to treat of AD will be reviewed.

The critical role of γ-secretase and its inhibitors in cancer and cancer therapeutics

As a multi-substrate transmembrane protease, γ-secretase exists widely in various cells. It controls multiple important cellular activities through substrate cleavage. γ-secretase inhibitors (GSIs) play a role in cancer inhibition by blocking Notch cleavage, and are considered as potential therapeutic strategies for cancer. Currently, GSIs have encouraging performance in preclinical models, yet this success does not translate well in clinical trials. In recent years, a number of breakthrough discoveries have shown us the promise of targeting γ-secretase for the treatment of cancer. Here, we integrate a large amount of data from γ-secretase and its inhibitors and cancer in nearly 30 years, comb and discuss the close connection between γ-secretase and cancer, as well as the potential and problems of current GSIs in cancer treatment. We analyze the possible reasons for the failure performance of current GSIs in clinical trials, and make recommendations for future research areas.

Presenilin-1 (PSEN1) Mutations: Clinical Phenotypes beyond Alzheimer's Disease

Presenilin 1 (PSEN1) is a part of the gamma secretase complex with several interacting substrates, including amyloid precursor protein (APP), Notch, adhesion proteins and beta catenin. PSEN1 has been extensively studied in neurodegeneration, and more than 300 PSEN1 mutations have been discovered to date. In addition to the classical early onset Alzheimer's disease (EOAD) phenotypes, PSEN1 mutations were discovered in several atypical AD or non-AD phenotypes, such as frontotemporal dementia (FTD), Parkinson's disease (PD), dementia with Lewy bodies (DLB) or spastic paraparesis (SP). For example, Leu113Pro, Leu226Phe, Met233Leu and an Arg352 duplication were discovered in patients with FTD, while Pro436Gln, Arg278Gln and Pro284Leu mutations were also reported in patients with motor dysfunctions. Interestingly, PSEN1 mutations may also impact non-neurodegenerative phenotypes, including PSEN1 Pro242fs, which could cause acne inversa, while Asp333Gly was reported in a family with dilated cardiomyopathy. The phenotypic diversity suggests that PSEN1 may be responsible for atypical disease phenotypes or types of disease other than AD. Taken together, neurodegenerative diseases such as AD, PD, DLB and FTD may share several common hallmarks (cognitive and motor impairment, associated with abnormal protein aggregates). These findings suggested that PSEN1 may interact with risk modifiers, which may result in alternative disease phenotypes such as DLB or FTD phenotypes, or through less-dominant amyloid pathways. Next-generation sequencing and/or biomarker analysis may be essential in clearly differentiating the possible disease phenotypes and pathways associated with non-AD phenotypes.

Estimation of genotoxicity, apoptosis and oxidative stress induction by TiO2 nanoparticles and acrylamide subacute oral coadministration in mice

Acrylamide is used in the industry and can be a by-product of high-temperature food processing which has toxic potential in various tissues, and titanium dioxide nanoparticles (TiO₂NPs) are widely used in toothpaste, sweets, food perseveration, chewing gum and medicines. Consequently, humans are daily exposed to large amounts of acrylamide and TiO₂NPs mainly through food intake. However, limited studies are available on the effect of simultaneously intake of acrylamide and TiO₂NPs on the integrity of genomic DNA and the induction of apoptosis in brain tissues. Therefore, this study estimated the influence of acrylamide coadministration on TiO₂NPs induced genomic instability and oxidative stress in the brain tissues of mice. To achieve this, mice were orally administrated acrylamide (3 mg/kg b.w) or/and TiO₂NPs (5 mg/kg b.w) for two successive weeks (5 days per week). The comet assay results showed that concurrent oral administration of acrylamide and TiO₂NPs strongly induced single- and double stranded DNA breaks, and that the level of reactive oxygen species (ROS) was also highly elevated within neural cells after simultaneous oral intake of acrylamide and TiO₂NPs compared to those observed after administration of acrylamide or/TiO₂NPs alone. Moreover, oral co-administration of acrylamide with TiO₂NPs increased apoptotic DNA damage to neurons by upregulating the expression levels of P53, TNF-α, IL-6 and Presenillin-1 genes compared to groups administered TiO₂NPs. Therefore, from these results, the present study concluded that coadministration of acrylamide renders TiO₂NPs more genotoxic and motivates apoptotic DNA damage and oxidative stress induced by TiO₂NPs in brain cells, and thus it is recommended to avoid concurrent oral acrylamide administration with TiO₂NPs.

Role of Presenilin-1 in Aggressive Human Melanoma

Presenilin-1 (PS-1), a component of the gamma (γ)-secretase catalytic complex, has been implicated in Alzheimer’s disease (AD) and in tumorigenesis. Interestingly, AD risk is inversely related to melanoma, suggesting that AD-related factors, such as PS-1, may affect melanomagenesis. PS-1 has been shown to reduce Wnt activity by promoting degradation of beta-catenin (β-catenin), an important Wnt signaling partner. Since Wnt is known to enhance progression of different cancers, including melanoma, we hypothesized that PS-1 could affect Wnt-associated melanoma aggressiveness. Western blot results showed that aggressive melanoma cells expressed significantly lower levels of both PS-1 and phosphorylated-β-catenin (P-β-catenin) than nonaggressive melanoma cells. Immunohistochemistry of human melanoma samples showed significantly reduced staining for PS-1 in advanced stage melanoma compared with early stage melanoma. Furthermore, γ-secretase inhibitor (GSI) treatment of aggressive melanoma cells was followed by significant increases in PS-1 and P-β-catenin levels, suggesting impaired Wnt signaling activity as PS-1 expression increased. Finally, a significant reduction in cell migration was associated with the higher levels of PS-1 and P-β-catenin in the GSI-treated aggressive melanoma cells. We demonstrate for the first time that PS-1 levels can be used to assess melanoma aggressiveness and suggest that by enhancing PS-1 expression, Wnt-dependent melanoma progression may be reduced

Activating transcription factor 2 promotes the progression of hepatocellular carcinoma by inducing the activation of the WHSC1-mediated TOP2A/PI3K/AKT axis

Activating transcription factor 2 (ATF2) is a tumor driver gene implicated in several human malignancies. This study aimed to determine the roles of ATF2 and its related molecules in the tumorigenesis of hepatocellular carcinoma (HCC). According to the Pan-cancer bioinformatics system, ATF2 is highly expressed in HCC. An increase in the expression of ATF2 was identified in clinically collected tumor tissues and procured HCC cells. The silencing of ATF2 reduced the viability, colony formation, invasion, and death resistance of HepG2 and SNU-398 cells in vitro. ATF2 promoted the transcription of Wolf-Hirschhorn syndrome candidate 1 (WHSC1) by binding to its promoter. WHSC1 further increased the expression of DNA topoisomerase II alpha (TOP2A) in HCC by inducing the dimethylation of histone H3 lysine 36 (H3K36me2) in the TOP2A promoter region. TOP2A activated the oncogenic PI3K/AKT signaling pathway. Further overexpression of WHSC1 activated the TOP2A/PI3K/AKT axis and restored the malignant behaviors of HCC cells suppressed by ATF2 silencing in vitro. In summary, this study demonstrated that, depending on WHSC1, ATF2 can activate the TOP2A/PI3K/AKT signaling cascade to promote the tumorigenesis of HCC. ATF2, WHSC1, and TOP2A may serve as potential targets in managing HCC.

A diagnostic and prognostic value of blood-based circulating long non-coding RNAs in Thyroid, Pancreatic and Ovarian Cancer

Several studies have demonstrated the potential of circulating long non-coding RNAs (lncRNAs) as promising cancer biomarkers. Herein, we addressed the regulatory role of circulating lncRNAs and their potential value as diagnostic/prognostic markers for thyroid, pancreatic and ovarian cancers. Furthermore, we analyzed and measured the clinical implications and association of lncRNAs with sensitivity, specificity, and area under the ROC curve (AUC). Based on our meta-analysis, we found that GAS8-AS1 could discriminate thyroid cancer from non-cancer and other cancers with higher accuracy (AUC = 0.746; sensitivity = 61.70%, and specificity = 90.00%). Similarly, for ovarian cancer, lncRNA RP5-837J1.2 was found to have ideal diagnostic potential with critical clinical specifications of AUC = 0.996; sensitivity = 97.30% and specificity = 94.60%. Whereas we could not find any lncRNA having high diagnostic/prognostic efficiency in pancreatic cancer. We believe that lncRNAs mentioned above may explore clinical settings for the diagnosis and prognosis of cancer patients.

Presenilin1 inhibits glioblastoma cell invasiveness via promoting Sortilin cleavage

BACKGROUND

Alzheimer's disease (AD) and glioblastoma are the most common and devastating diseases in the neurology and neurosurgery departments, respectively. Our previous research reports that the AD-related protein Presenilin1 represses cell proliferation by inhibiting the Wnt/β-catenin pathway in glioblastoma. However, the function of Presenilin1 and the underlying mechanism need to be further investigated.

METHODS

The correlations of two genes were conducted on the R2 microarray platform and CGGA. Wound healing, Transwell assays and glioblastoma transplantation were performed to detect invasion ability. Phalloidin staining was employed to show cell morphology. Proximity ligation assays and protein docking assays were employed to detect two protein locations. We also employed western blotting to detect protein expression.

RESULTS

We found that Presenilin1 clearly repressed the migration, invasion and mesenchymal transition of glioblastoma cells. Intriguingly, we observed that the expression of Presenilin1 was positively correlated with Sortilin, which is identified as a pro-invasion molecule in glioma. Furthermore, Presenilin1 interacted with Sortilin at the transmembrane domain and repressed Sortilin expression by cleaving it in glioblastoma cells. First, we found that Sortilin introduced the function of Presenilin1 in phosphorylating β-catenin and repressing invasion in glioblastoma cells. Last, Presenilin1 stimulation sharply suppressed the invasion and mesenchymal transition of glioblastoma in mouse subcutaneous and intracranial transplantation models.

CONCLUSIONS

Our study reveals that Sortilin mediates the regulation of β-catenin by Presenilin1 and transduces the anti-invasive function of Presenilin1, which may provide novel therapeutic targets for glioblastoma treatment. Video Abstract.