Differential roles and activation of mammalian target of rapamycin complexes 1 and 2 during cell migration in prostate cancer cells

BACKGROUND

Mammalian target of rapamycin (mTOR) is a downstream substrate activated by PI3K/AKT pathway and it is essential for cell migration. It exists as two complexes: mTORC1 and mTORC2. mTORC1 is known to be regulated by active AKT, but the activation of mTORC2 is poorly understood. In this study, we investigated the roles and differential activation of the two mTOR complexes during cell migration in prostate cancer cells.

METHODS

We used small interfering RNA to silence the expression of Rac1 and the main components of mTOR complexes (regulatory associated protein of mTOR [RAPTOR] and rapamycin-insensitive companion of mTOR [RICTOR]) in LNCaP, DU145, and PC3 prostate cancer cell lines. We performed transwell migration assay to evaluate the migratory capability of the cells, and Western blot analysis to study the activation levels of mTOR complexes.

RESULTS

Specific knockdown of RAPTOR and RICTOR caused a decrease of cell migration, suggesting their essential role in prostate cancer cell movement. Furthermore, epidermal growth factor (EGF) treatments induced the activation of both the mTOR complexes. Lack of Rac1 activity in prostate cancer cells blocked EGF-induced activation of mTORC2, but had no effect on mTORC1 activation. Furthermore, the overexpression of constitutively active Rac1 resulted in significant increase in cell migration and activation of mTORC2 in PC3 cells, but had no effect on mTORC1 activation. Active Rac1 was localized in the plasma membrane and was found to be in a protein complex, with RICTOR, but not RAPTOR.

CONCLUSION

We suggest that EGF-induced activation of Rac1 causes the activation of mTORC2 via RICTOR. This mechanism plays a critical role in prostate cancer cell migration.

Molecular docking, anti-proliferative activity and induction of apoptosis in human liver cancer cells treated with androstane derivatives: Implication of PI3K/AKT/mTOR pathway

Worldwide, cancer is still an area with high unmet medical need. Lead optimization efforts towards structure-based drug design were employed to discover newly synthesized hetero-steroid derivatives with promising anticancer effects against hepatocellular carcinoma (HCC). The aim of our study is to evaluate the anti-proliferative activity and the mechanism, a dual PI3K/mTOR inhibitor, and mechanism of action of a series of heterocylic androstane derivatives as anti-HCC agent. The cytotoxic effects of different heterocylic androstanes and 5FU as single agents, were assessed against both HepG2 cells and Non-malignant MDCK cell line to assess the toxicity. Then the underlying mechanism of compound 4 as most promising compound was evaluated using molecular docking, MTT assay, cell cycle analysis, DNA fragmentation, and real-time PCR. The results of MTT assay showed potential cytotoxic effect for compound 4 and 5 against liver cancer cell line with IC₅₀ value 39.81 and 57.54 μM, respectively. Inhibition of the PI3K/AKT/mTOR pathway was achieved by compound 4, which was documented by molecular docking and augmented by gene expression analysis. Detailed mechanism revealed that compound 4 induced cell cycle arrest, DNA fragmentation, and induction of apoptosis by inhibition of anti-apoptotic genes, and upregulation of apoptotic genes. Our results shed a light on aminopyrazoloandrostane derivative 4 as an inhibitor of the PI3K/AKT/mTOR pathway, which might be acting as promising anti-liver cancer agent. Our data support further investigation of agents targeting the PI3K/AKT/mTOR.

Neferine hinders choriocarcinoma cell proliferation, migration and invasion through repression of long noncoding RNA-CHRF

The comprehensive pathological peculiarities of Neferine (NEF) have been testified in disparate diseases. But, the functions of NEF in choriocarcinoma progression remain unexplored. The research endeavoured to uncover the anti-tumour action of NEF in choriocarcinoma cells. NEF at diverse doses was employed to dispose JEG-3 and HTR-8 cells, and cell viability assessment adopted CCK-8 assay. After 60 μg/mL NEF management, BrdU-positive cells, apoptosis, migration, invasion and correlative factors were assessed. CHRF expression in choriocarcinoma tumour and choriocarcinoma cell lines was estimated via RT-qPCR. Then, the functions of overexpressed CHRF in NEF-disposed cells were determined. At last, impacts of NEF on PI3K/AKT/mTOR and ERK1/2 pathways were evaluated. Results showed that NEF restrained cell proliferation, triggered apoptosis and repressed migration and invasion in JEG-3 and HTR-8 cells. CHRF was ascended in choriocarcinoma tissues and NEF repressed CHRF expression in choriocarcinoma cell lines. Additionally, overexpressed CHRF abolished the above functions of NEF in choriocarcinoma cells proliferation, apoptosis, migration and invasion. Further, NEF impeded PI3K/AKT/mTOR and ERK1/2 pathways via repressing CHRF. The explorations testified that NEF exhibited the anti-tumour action in JEG-3 and HTR-8 cells via hindering PI3K/AKT/mTOR and ERK1/2 pathways by mediating CHRF.

The Current Genomic and Molecular Landscape of Philadelphia-like Acute Lymphoblastic Leukemia

Philadelphia (Ph)-like acute lymphoblastic leukemia (ALL) is a high-risk B-cell Acute Lymphoblastic Leukemia (B-ALL) characterized by a gene expression profile similar to Ph-positive B-ALL but lacking the BCR-ABL1 translocation. The molecular pathogenesis of Ph-like B-ALL is heterogenous and involves aberrant genomics, receptor overexpression, kinase fusions, and mutations leading to kinase signaling activation, leukemogenic cellular proliferation, and differentiation blockade. Testing for the Ph-like signature, once only a research technique, is now available to the clinical oncologist. The plethora of data pointing to poor outcomes for this ALL subset has triggered investigations into the role of targeted therapies, predominantly involving tyrosine kinase inhibitors that are showing promising results.

3,4,5-Tri-O-caffeoylquinic acid methyl ester isolated from Lonicera japonica Thunb. Flower buds facilitates hepatitis B virus replication in HepG2.2.15 cells

Caffeoylquinic acids are well known for their prominent antiviral activities. Beyond our expectations, we initially found 3,4,5-Tri-O-caffeoylquinic acid methyl ester (3,4,5-CQME) from L. japonica can facilitate HBV DNA and antigens secretion. This study aimed to investigate its underlying molecular mechanism. The results indicate that 3,4,5-CQME signally increased intracellular and secreted HBsAg levels by more than two times in HepG2.2.15 cells and HepAD38 cells. Furthermore, levels of HBeAg, HBV DNA and RNA were significantly enhanced by 3-day 3,4,5-CQME treatment; it didn't directly affect intracellular cccDNA amount, although it slightly increased cccDNA accumulation as a HBV DNA replication feedback. In addition, treatment with 3,4,5-CQME significantly induced HBx protein expression for viral replication. We utilized a phospho-antibody assay to profile the signal transduction change by 3,4,5-CQME to illuminate its molecular mechanism. The results indicate that treatment with 3,4,5-CQME activated AKT/mTOR, MAPK and NF-κB pathways verified by immunoblot. Moreover, 3,4,5-CQME upregulated the expression of nuclear transcriptional factors PGC1α and PPARα. In short, 3,4,5-CQME promotes HBV transcription and replication by upregulating HBx expression and activating HBV transcriptional regulation-related signals. As caffeoylquinic acids are widely present in traditional Chinese medicines, the risk of intaking caffeoylquinic acids-containing herbs for hepatitis B treatment requires more evaluation and further research.

Squamous cell transformation as a mechanism of acquired resistance to tyrosine kinase inhibitor in EGFR-mutated lung adenocarcinoma: a report of two cases

Pathological transformation to squamous cell carcinoma after epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor treatment has been reported, but details of the transformation remain unclear. We report two cases with transformation to squamous cell carcinoma. The first case was a 61-year-old man who was an ex-smoker with stage IV lung adenocarcinoma harbouring EGFR exon 19 insertion. He experienced squamous cell transformation after 28 months of erlotinib therapy. Next-generation sequencing (NGS) analysis showed EGFR T790M and genomic alterations in PTEN, PDGFR, and HRAS. The second case was a 72-year-old man who was an ex-smoker with stage IV lung adenocarcinoma harbouring EGFR exon 21 L858R. He experienced squamous cell transformation after nine months of erlotinib therapy. NGS analysis showed EGFR T790M and genomic alterations in PTEN, SMARCB1, TP53, and KIT. Both patients had PTEN genomic alterations and the PI3K/AKT/mTOR (mammalian target of rapamycin) pathway might play an important role in squamous cell transformation.

Putative functional variants of PI3K/AKT/mTOR pathway are associated with knee osteoarthritis susceptibility

BACKGROUND

Osteoarthritis (OA) is a degenerative musculoskeletal disease which causes joint deformity and pain and finally leads to limb dysfunction. Knee osteoarthritis (KOA) has the highest incidence among all kinds of OA. Strong evidence leads to the understanding that P13K/AKT/mTOR signaling is very important in cartilage degeneration.

METHODS

This research sought to understand the association between genetic variation of PI3K/AKT/mTOR genes and KOA susceptibility among Chinese population. All the genetic variants of PI3K/AKT/mTOR pathway were graded and selected using RegulomeDB database, and then, an association study including 278 osteoarthritis patients and 289 controls was conducted.

RESULTS

Finally, eight SNPs' genotypes' distributions and susceptibility to KOA were presented. AKT1 rs2498789 was associated with KOA susceptibility in dominate genetic model (AA + GA vs GG) after adjusted for BMI, age, and gender: OR = 1.46, 95% CI: 1.03-2.05, P = .03. PIK3CA rs7646409 was also associated with KOA susceptibility (TC vs TT) after adjusted for BMI, age, and gender: OR = 0.58, 95% CI: 0.36-0.93, P = .02. PIK3CA rs7646409 (TC vs TT) with KOA risk was more significant in age < 60 group (P for heterogeneity was .03). Risk score showed significant association with KOA susceptibility after cumulative analysis (OR = 2.45, 95% CI: 1.35-4.45, P = .003).

CONCLUSIONS

This study shows that genetic variation of PI3K/AKT/mTOR is associated with KOA susceptibility in Chinese Han population, indicating that PI3K/AKT/mTOR is very important in KOA pathogenesis.

Repression of Kisspeptin1 weakens hydrogen peroxide-caused injury in HTR8 cells via adjusting PI3K/AKT/mTOR pathway

Kisspeptin1 (KISS1) is a tumor metastatic suppressor, and its increased expression is validated in human placenta trophoblast cells. Nonetheless, the actions of KISS1 in hydrogen peroxide (H₂ O₂ )-impaired human trophoblast HTR8 cells still remain imprecise. This research aims to uncover whether KISS1 can mitigate H₂ O₂ -triggered cell injury. HTR8 cells were pretreated with 250 μM H₂ O₂ for 4 hours; the autophagic markers (Beclin-1 and LC3B), cell viability, invasion and apoptosis were appraised. Real-time quantitative polymerase chain reaction and Western blot trials were enforced for the valuation of KISS1 mRNA and protein levels. After si-KISS1 transfection and 3-MA manipulation, the aforesaid biological processes were reassessed for ascertaining the influences of repressed KISS1 in H₂ O₂ -impaired HTR8 cells. Phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway was eventually estimated. H₂ O₂ enhanced Beclin-1 and LC3B expression, restricted cell viability, and invasion, and meanwhile caused apoptosis. The elevation of KISS1 evoked by H₂ O₂ was observed in HTR8 cells. In addition, silencing KISS1 was distinctly annulled the function of H₂ O₂ in HTR8 cells. Eventually, we observed that the repression of KISS1 triggered the activation of PI3K/AKT/mTOR in HTR8 cells under H₂ O₂ management. The diverting research unveiled that KISS1 repression eased H₂ O₂ -caused HTR8 cells injury via mediating PI3K/AKT/mTOR pathway.

MiR-155-5p exerts tumor-suppressing functions in Wilms tumor by targeting IGF2 via the PI3K signaling pathway

BACKGROUND

MicroRNA-155-5p (miR-155-5p) has been reported to play an oncogenic role in different human malignancies; however, its role in Wilms tumor (WT) remains unclear.

METHODS

Differentially expressed miRNAs (DE-miRNAs) and mRNAs (DEGs) in WT blood and tissues were identified by using miRNA microarray and RNA-sequencing. Bioinformatics prediction and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to predict the potential functions of DE-miRNAs. DE-miRNAs and DEGs in WT obtained from Gene Expression Omnibus (GEO) and Therapeutically Applicable Research to Generate Effective Treatments (TARGET) were identified by using the "edgeR" package. RT-qPCR was used to explore miR-155-5p and IGF2 expression and their clinical significance in WT specimens. A rhabdoid cell line (G401) and Ewing sarcoma cell line (SK-NEP-1) were used. Immunohistochemical staining, western blotting and dual-luciferase reporter assays were performed to study the mechanisms involved. The CCK-8, flow cytometry, wound healing and transwell assays were performed to identify the effects of miR-155-5p and IGF2 knockdown on cell proliferation, apoptosis, migration and invasion, respectively.

RESULTS

MiR-155-5p was downregulated in both blood and tissues from WT patients who did not receive chemotherapy before surgery but was upregulated in tissues from WT patients who had received chemotherapy before surgery. IGF2, PI3K, AKT and mTOR were found to be upregulated in WT tissues. Additionally, miR-155-5p and IGF2 were significantly correlated with TNM stage and lymphatic metastasis in WT patients. Molecular mechanism exploration indicated that IGF2 was downregulated by miR-155-5p via direct binding to its 3' untranslated region in cell lines. Furthermore, IGF2, PI3K, AKT and mTOR expression was inversely correlated with miR-155-5p expression, and PI3K, AKT and mTOR expression was positively correlated with IGF2 expression in cell culture. Functional studies demonstrated that miR-155-5p upregulation and IGF2 knockdown suppressed cell proliferation, migration and invasion and induced cell apoptosis. Moreover, the tumor-suppressing effects of miR-155-5p in cells were abrogated by miR-155-5p inhibitor treatment.

CONCLUSIONS

Taken together, these findings suggest that miR-155-5p functions as a tumor suppressor in WT through inactivating the PI3K/AKT/mTOR signaling pathway by directly targeting IGF2. Thus, miR-155-5p might be a novel therapeutic target for WT.

Aerobic Endurance Exercise Ameliorates Renal Vascular Sclerosis in Aged Mice by Regulating PI3K/AKT/mTOR Signaling Pathway

Renal vascular sclerosis caused by aging plays an important role in the occurrence and development of chronic kidney disease. Clinical studies have confirmed that endurance exercise is able to delay the aging of skeletal muscle and brain tissue. However, to date, few studies have assessed whether endurance exercise is able to improve the occurrence of renal vascular sclerosis caused by natural aging and its related mechanisms. In this study, we investigated the protective effect of aerobic endurance exercise on renal vascular sclerosis in aged mice and its effect on the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway. The results suggested that aerobic endurance exercise preserved kidney morphology and renal function. Glomerular basement membrane thickness was evidently increased, podocyte foot processes were effaced in aged mice, and aerobic endurance exercise significantly ameliorated the overall lesion range. The protein expression of vascular endothelial growth factor (VEGF) and JG12 was lower in the senile control group (OC group). The protein expression of VEGF and JG12 was significantly increased after aerobic endurance exercise. Furthermore, aerobic endurance exercise resulted in downregulation of Bax, Caspase 3, IL-6, and senescent cells and upregulation of Bcl-2. The upregulation of PI3K and its downstream signal molecules AKT and mTOR after aerobic endurance exercise was further observed. Our observations indicated that aerobic endurance exercise may inhibit renal vascular sclerosis in aged mice by regulating the PI3K/AKT/mTOR signaling pathway.

Investigating the potential of LSKL peptide as a novel hypertrophic scar treatment

Hypertrophic scar (HTS) is a common pathologic dermal fibroproliferative disease after skin injury. Transforming growth factor β (TGF-β) plays a central role in HTS formation and development. Thrombospondin-1 (TSP-1) activates latent TGF-β by binding to latency-associated peptide-β on TGF-β structure. So far, LSKL peptide was shown to selectively antagonize TSP-1. In this study, TSP-1 was first confirmed to be highly expressed in HTS. LSKL peptide was proven to inhibit the overexpression of extracellular matrix and contractile ability of HTS fibroblasts. In vivo, LSKL could attenuate the thickness of HTS, distortion of collagen alignment and fibrogenesis. Results also demonstrated that LSKL peptide not only remarkably attenuated cell proliferation and migration, but also induced cell apoptosis of HTS fibroblasts. Western blot analysis further revealed that LSKL peptide significantly suppressed the phosphorylation of PI3K, AKT, and mTOR, while not affecting the phosphorylation of Smad2/3 and MEK/ERK. These findings suggested that LSKL might be a promising anti-fibrosis agent to HTS through PI3K/AKT/mTOR signaling pathway.

Pyridinecarboxylic Acid Derivative Stimulates Pro-Angiogenic Mediators by PI3K/AKT/mTOR and Inhibits Reactive Nitrogen and Oxygen Species and NF-κB Activation Through a PPARγ-Dependent Pathway in T. cruzi-Infected Macrophages

Chagas disease is caused by Trypanosoma cruzi infection and represents an important public health concern in Latin America. Macrophages are one of the main infiltrating leukocytes in response to infection. Parasite persistence could trigger a sustained activation of these cells, contributing to the damage observed in this pathology, particularly in the heart. HP₂₄, a pyridinecarboxylic acid derivative, is a new PPARγ ligand that exerts anti-inflammatory and pro-angiogenic effects. The aim of this work was to deepen the study of the mechanisms involved in the pro-angiogenic and anti-inflammatory effects of HP₂₄ in T. cruzi-infected macrophages, which have not yet been elucidated. We show for the first time that HP₂₄ increases expression of VEGF-A and eNOS through PI3K/AKT/mTOR and PPARγ pathways and that HP₂₄ inhibits iNOS expression and NO release, a pro-inflammatory mediator, through PPARγ-dependent mechanisms. Furthermore, this study shows that HP₂₄ modulates H₂O₂ production in a PPARγ-dependent manner. It is also demonstrated that this new PPARγ ligand inhibits the NF-κB pathway. HP₂₄ inhibits IKK phosphorylation and IκB-α degradation, as well as p65 translocation to the nucleus in a PPARγ-dependent manner. In Chagas disease, both the sustained increment in pro-inflammatory mediators and microvascular abnormalities are crucial aspects for the generation of cardiac damage. Elucidating the mechanism of action of new PPARγ ligands is highly attractive, given the fact that it can be used as an adjuvant therapy, particularly in the case of Chagas disease in which inflammation and tissue remodeling play an important role in the pathophysiology of this disease.

Hotspot Mutations in DICER1 Causing GLOW Syndrome-Associated Macrocephaly via Modulation of Specific microRNA Populations Result in the Activation of PI3K/ATK/mTOR Signaling

BACKGROUND

We have previously described mosaic mutations in the RNase IIIb domain of DICER1that display global developmental delays, lung cysts, somatic overgrowth, macrocephaly and Wilms tumor. This constellation of phenotypes was classified as GLOW syndrome. Due to the phenotypic overlap between GLOW and syndromes caused by mutations in the PI3K/AKT/mTOR pathway, we hypothesized that alterations in miRNA regulation of this pathway cause its specific constellation of phenotypes.

OBJECTIVE

To test the hypothesis that DICER1 "hot spot" mutations associated with GLOW syndrome activate PI3K/AKT/mTOR signaling.

METHODS

We developed HEK293T cells with loss of exon 25 in DICER1, a genetic modification that is synonymous with the "hot spot" RNAseIIIb mutations that cause GLOW syndrome. We assayed the cells for activation of the PI3K/AKT/mTOR signaling pathway.

RESULTS

We observed activation of the PI3K/AKT/mTOR pathway as demonstrated by increased pS6Kinase, p4EBP1 and pTSC2 levels. Additionally, these cells demonstrate a striking cellular phenotype, with the ability to form spheres when the serum is removed from their growth medium. The cells in these spheres are Oct4 and Sox2 positive and exhibit the property of reversion with the addition of serum. We queried miRNA expression data and identified a population of miRNAs that increase due to these mutations and target negative regulators of the PI3K/AKT/mTOR pathway.

CONCLUSION

This work identifies the delicate and essential role for miRNA control of the PI3K/AKT/mTOR pathway. We conclude that the phenotypes observed in the GLOW syndrome are the result of PI3K/AKT/mTOR activation.

Salidroside induces apoptosis and protective autophagy in human gastric cancer AGS cells through the PI3K/Akt/mTOR pathway

Salidroside, a natural active ingredient extracted from Rhodiola rosea, has been shown to exert antitumor activity against breast cancer Dong Young et al. [1], colon cancer Sun et al. [2] and bladder cancer Tian et al. [3]. However, the effect of salidroside on apoptosis and autophagy in gastric cancer remains unclear. In our research, we observed the biological effect of salidroside on human gastric cancer AGS cells. Our results demonstrated that salidroside inhibited the growth of AGS cells both in vivo and in vitro and exerted a proapoptotic effect on AGS cells as confirmed by flow cytometry, Hoechst staining and western blot analysis. Additionally, we found that salidroside decreased the phosphorylation of PI3K and Akt and that pretreatment with the PI3K/Akt agonist IGF-1 could weaken the proapoptotic effect of salidroside. Interestingly, the exposure of AGS cells to salidroside induced autophagy as indicated by transmission electron microscopy, mRFP-GFP-LC3 transfection and western blot analysis, suggesting that salidroside promoted autophagy in gastric cancer AGS cells. Furthermore, treatment with the autophagy inhibitor chloroquine enhanced salidroside-induced cell apoptosis, indicating that the autophagy mediated by salidroside may protect AGS cells from death. Additionally, we found that salidroside decreased the level of p-mTOR protein in a concentration-dependent manner and that pretreatment with IGF-1 decreased the expression of autophagy proteins, suggesting that salidroside induced autophagy through the PI3K/Akt/mTOR pathway. The above findings indicate that salidroside inhibited the growth of gastric cancer and induced apoptosis and protective autophagy through the PI3K/Akt/mTOR pathway. In summary, our study provides novel insights regarding the activity of salidroside against gastric cancer and contributes to the clinical application of salidroside combined with autophagy inhibitors as a chemotherapeutic strategy for human gastric cancer.

Icariin alleviates hypoxia-induced damage in MC3T3-E1 cells by downregulating TALNEC2

Osteonecrosis is a harmful musculoskeletal disease. We aim to detect the effects of icariin (ICA) in MC3T3-E1 cell. MC3T3-E1 cell was pretreated with ICA and was subjected to hypoxia stimuli. The tumor-associated long noncoding RNA expressed on chromosome 2 (TALNEC2) overexpression or silencing vectors (pTALNEC2 or si-TALNEC2) was utilized for MC3T3-E1 cell transfection. Viability and apoptosis rate were individually tested by cell counting kit-8 and Annexin V-fluorescein isothiocyanate/propidium iodide kit untied with flow cytometry. The alkaline phosphatase activity (ALP) activity was tested through ALP assay. The quantitative reverse transcription PCR or Western blot was performed for elements detection at the RNA or protein level. Hypoxia treatment induced viability inhibition and CyclinD1 reduction, but elevation of p53 and p16. It also promoted apoptosis by increasing apoptotic cells, Bax, and cleaved-poly ADP-ribose polymerase but decreasing Bcl-2. Also, hypoxia stimuli restrained ALP activity, and osteopontin, osteocalcin, and Runt-related transcription factor 2 expression. Those effects caused by hypoxia stimuli were all reversed by ICA. TALNEC2 was downregulated by ICA, whose impacts were subsequently abolished by pTALNEC2. Silencing TALNEC2 displayed similar effects with ICA. But the apoptosis was not affected by si-TALNEC2. ICA blocked ste20-related proline/alanine-rich kinase/c-Jun N-terminal kinase (SPAK/JNK) but triggered phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway in MC3T3-E1 cell by suppressing TALNEC2. ICA relieved hypoxia-stimulated damage by restraining TALNEC2 through blocking SPAK/JNK and triggering PI3K/AKT/mTOR in the MC3T3-E1 cell.

LncRNA nuclear-enriched abundant transcript 1 regulates hypoxia-evoked apoptosis and autophagy via mediation of microRNA-181b

Nuclear-enriched abundant transcript 1 (NEAT1), a vital long noncoding RNA (lncRNA), exhibits the functions in disparate cancers. Nevertheless, the influences of NEAT1 in congenital heart disease (CHD) remain unreported. The research delves into whether NEAT1 affects H9c2 cells apoptosis and autophagy under the hypoxia condition. Overexpressed NEAT1 vector was transfected into H9c2 cells; then, functions of NEAT1 in cell viability, apoptosis, autophagy, PI3K/AKT/mTOR and JAK1/STAT3 pathways were detected in H9c2 cells under hypoxia condition. Expression of NEAT1 and miR-181b in hypoxia and blood samples from CHD was evaluated. After miR-181b inhibitor transfection, functions of miR-181b repression in the above-mentioned cell behavior and PI3K/AKT/mTOR and JAK1/STAT3 pathways were reassessed. Overexpressed NEAT1 clearly allayed hypoxia-triggered H9c2 cells apoptosis and autophagy. The decreased NEAT1 and miR-181b were showcased in hypoxia and blood samples from CHD; meanwhile, elevated miR-181b evoked by overexpressed NEAT1 was observed in hypoxia-managed H9c2 cells. More importantly, miR-181b inhibition obviously overturned the influences of NEAT1 in hypoxia-affected H9c2 cells apoptosis and autophagy. Besides, overexpressed NEAT1 facilitated PI3K/AKT/mTOR and JAK1/STAT3 activations via enhancing miR-181b. The research exposed that NEAT1 eased hypoxia-triggered H9c2 cells apoptosis and autophagy by expediting PI3K/AKT/mTOR and JAK1/STAT3 pathways via elevating miR-181b.

Targeting PI3K/AKT/mTOR-mediated autophagy for tumor therapy

Autophagy is a highly conserved catabolic process and participates in a variety of cellular biological activities. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, as a critical regulator of autophagy, is involved in the initiation and promotion of a series of pathological disorders including various tumors. Autophagy also participates in regulating the balance between the tumor and the tumor microenvironment. Natural products have been considered a treasure of new drug discoveries and are of great value to medicine. Mounting evidence has suggested that numerous natural products are targeting PI3K/AKT/mTOR-mediated autophagy, thereby suppressing tumor growth. Furthermore, autophagy plays a "double-edged sword" role in different tumors. Targeting PI3K/AKT/mTOR-mediated autophagy is an important therapeutic strategy for a variety of tumors, and plays important roles in enhancing the chemosensitivity of tumor cells and avoiding drug resistance. Therefore, we summarized the roles of PI3K/AKT/mTOR-mediated autophagy in tumorigenesis, progression, and drug resistance of tumors, which may be utilized to design preferably therapeutic strategies for various tumors.

Berberine attenuated the cytotoxicity induced by t-BHP via inhibiting oxidative stress and mitochondria dysfunction in PC-12 cells

Neurodegenerative diseases all share several common features such as involvement of oxidative damage and mitochondrial dysfunction in pathogenesis. Oxidative stress induced by overproduction of mitochondrial reactive oxygen species (ROS) or impairment of the antioxidant deficiency results in mitochondrial dysfunction and initiation of the cell death cascade. Berberine (BBR), a traditional Chinese medicine, has been reported to exert anti-oxidative stress and anti-apoptosis effect in CNS diseases. However, the mechanism of BBR on regulating mitophagy and protecting mitochondrial function under oxidative stress remains unclear. In present study, we evaluated the beneficial effects of BBR on the tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity. Furthermore, we explored the protective role of BBR in mitochondrial function and mitophagy under oxidative stress in PC-12 cells. Our results demonstrated that BBR effectively inhibited t-BHP-induced apoptosis which is associated with the decreased leakage of lactate dehydrogenase (LDH) and ROS overproduction. Moreover, BBR significantly suppressed cytochrome c expression, upregulated the ratio of Bcl-2/Bax, and ameliorated mitochondrial dysfunction by optimizing mitochondria membrane potential (ΔΨm) status and ATP production. In addition, BBR reduced the expression of autophagy-specific marker LC3, SQTM1/p62, and maintained lysosome normal function which involved the restoration of upstream signaling pathway AKT and mTOR phosphorylation level. Collectively, these findings suggested that BBR protects PC-12 cells from oxidative injury through inhibiting ROS level, mitochondria dysfunction, and mitophagy via PI3K/AKT/mTOR signaling pathways, which suggest a potential therapeutic strategy for oxidative stress and neurotoxic damages.

Torin2 Exploits Replication and Checkpoint Vulnerabilities to Cause Death of PI3K-Activated Triple-Negative Breast Cancer Cells

Frequent mutation of PI3K/AKT/mTOR signaling pathway genes in human cancers has stimulated large investments in targeted drugs but clinical successes are rare. As a result, many cancers with high PI3K pathway activity, such as triple-negative breast cancer (TNBC), are treated primarily with chemotherapy. By systematically analyzing responses of TNBC cells to a diverse collection of PI3K pathway inhibitors, we find that one drug, Torin2, is unusually effective because it inhibits both mTOR and other PI3K-like kinases (PIKKs). In contrast to mTOR-selective inhibitors, Torin2 exploits dependencies on several kinases for S-phase progression and cell-cycle checkpoints, thereby causing accumulation of single-stranded DNA and death by replication catastrophe or mitotic failure. Thus, Torin2 and its chemical analogs represent a mechanistically distinct class of PI3K pathway inhibitors that are uniquely cytotoxic to TNBC cells. This insight could be translated therapeutically by further developing Torin2 analogs or combinations of existing mTOR and PIKK inhibitors.

Catalpol induces cell activity to promote axonal regeneration via the PI3K/AKT/mTOR pathway in vivo and in vitro stroke model

Background

To investigate the role and mechanism of catalpol on neuronal cell activity to promote axonal regeneration via PI3K/AKT/mTOR pathway after stroke.

Methods

In vivo the effect of catalpol (2.5, 5, 7.5 mg/kg; i.p) or vehicle administered 24 h after stroke and then daily for 7 days on behavior, Map-2⁺/p-S6⁺ and Map-2⁺/GAP-43⁺ immunofluorescence were assessed in a rat model of stroke. Then in vitro, an oxygen-glucose deprivation (OGD/R) model was established to observe the effect of catalpol (0.1, 1, 10 and 100 µg·mL^-1) on cultural neurons survive rate, neuronal cell activity and axon growth. Moreover, rapamycin (Rapa) was used to inhibit the mTOR pathway to observe the catalpol mechanism on neuronal cell activity to promote axonal growth, and the proteins related with PI3K/AKT/mTOR pathway were detected by Western blot assay.

Results

Repeated treatments with catalpol improved neurological score and significantly enhanced neuronal cell activity, then promote axonal regeneration after stroke. While in vitro, catalpol also increased the survive rate and axonal growth of the neurons. Catalpol can reversed the Rapa inhibited effects on neurons' survive and axon extending. Catalpol can also reversed proteins reduced by Rapa related with PI3K/AKT/mTOR pathway.

Conclusions

These results suggested that catalpol might contribute to internal neuronal cell activity and axonal regeneration by regulating PI3K/AKT/mTOR pathway.

Oridonin relieves hypoxia-evoked apoptosis and autophagy via modulating microRNA-214 in H9c2 cells

Oridonin (Orid) has been diffusely applied to remedy dissimilar cancers. Howbeit, the influence of Orid in ischemic heart disease (IHD) remains imprecise. The current study uncovered the functions of Orid in hypoxia-caused apoptosis and autophagy in H9c2 cells. H9c2 cells received hypoxia and Orid manipulation, cell viability, apoptosis, apoptosis-interrelated factors and autophagy-correlative factors were appraised. After the extraordinary vectors transfections, the impacts of miR-214 inhibition on hypoxia-triggered apoptosis and autophagy were investigated. Further, dual luciferase reporter assay was enforced for ascertaining the pertinence between miR-214 and PTEN. PI3K/AKT/mTOR pathway was finally determined using western blot. We found that, Orid significantly alleviated hypoxia-induced apoptosis and autophagy through regulation their associated proteins in H9c2 cells. Up-regulation of miR-214 was found in hypoxia and Orid co-managed cells, meanwhile, repression of miR-214 obviously annulled the modulatory functions of Orid in hypoxia-evoked apoptosis and autophagy. Additionally, PTEN was forecasted to be a firsthand target of miR-214. Besides, we observed that Orid evoked PI3K/AKT/mTOR activation through elevation of miR-214 in hypoxia-managed H9c2 cells. In conclusion, the amusing results corroborated that Orid relieved hypoxia-caused apoptosis and autophagy via adjusting PI3K/AKT/mTOR pathway through enhancement of miR-214 in H9c2 cells.

NRSN2 promotes breast cancer metastasis by activating PI3K/AKT/mTOR and NF-κB signaling pathways

Breast cancer is a leading cause of cancer-associated mortality globally amongst gynecologic tumors due to aggressive metastasis. A previous study reported that neurensin-2 (NRSN2) was implicated in human cancer cells, and that NRSN2 gene and protein expression levels were significantly upregulated in human breast cancer tissues compared with adjacent non-tumor tissues. The purpose of the present study was to analyze the role of NRSN2 in the metastasis of breast cancer cells and explore its potential mechanism. Reverse transcription-quantitative PCR, MTT, western blotting and immunohistochemistry was used to analyze the role of NRSN2 both in vitro and in vivo. The present study demonstrated that NRSN2 knockdown inhibited the proliferation, migration and invasion of breast cancer cells in vitro. NRSN2 upregulation promoted breast cancer cell proliferation and tissue growth in vitro and in vivo. In addition, the results demonstrated that the regulatory effects of NRSN2 on breast cancer cells were associated with PI3K/AKT/mTOR and NF-κB signaling pathway dysregulation. Furthermore, NRSN2 overexpression in mice significantly promoted breast cancer cell proliferation. In conclusion, the results from the present study indicated that NRSN2 may be considered as a novel oncogenic protein and may represent a potential therapeutic target for breast cancer.

The beneficial role of SIRT1 activator on chemo- and radiosensitization of breast cancer cells in response to IL-6

Tumor environmental cytokines, such as IL-6, has a major role in the outcome of radiation and chemotherapy. In this study, we hypothesized that IL-6 mediates its effects via SIRT1 as a protein deacetylase and activator of phosphatidylinositol-3 kinase pathways. In the present study, we evaluated the effects of the novel dual inhibitor of phosphatidylinositol-3 kinase/mammalian target of rapamycin, NVP-BEZ235, and SIRT1 inhibitor and activator plus radiotherapy in breast cancer cells treated with IL-6. Here, IL-6 untreated/pretreated human breast cancer cells were cultured with single or combination of NVP-BEZ235 and/or SIRT1 activator (SRT1720)/inhibitor (EX-527) under radiotherapy condition. After all treatments, the MTT assay and flow cytometry assay were used to explore cell viability and the ability of our treatments in altering cancer stem cells (CSCs) population or cellular death (apoptosis + necrosis) induction. Simultaneous exposure to NVP-BEZ235 and SRT1720 sensitized breast cancer cells to radiotherapy but elevated CSCs. Treatment with IL-6 for 2 weeks significantly decreased CSCs population. Activation of SIRT1 via SRT1720 in combination with NVP-BEZ235 significantly decreased breast cancer cells viability in IL-6 pretreatment cultures. Inhibition of SIRT1 via EX-527 diminished the beneficial effects of IL-6 pretreatment. The combination of NVP-BEZ235 and SRT1720 as a SIRT1 activation could effectively decrease breast cancer cells population and augments the efficacy of radiotherapy.

Betulinic acid induces autophagy-mediated apoptosis through suppression of the PI3K/AKT/mTOR signaling pathway and inhibits hepatocellular carcinoma

Betulinic acid (BA) is a pentacyclic triterpenoid compound that widely exists in Chinese herbal medicine, and it has remarkable biological activity. However, the involved molecular targets and mechanisms of BA are still ambiguous. Here, we aim to validate the preventive effects and molecular mechanisms of BA against hepatocellular carcinoma via related experiments. We extracted the 2D and 3D structure of BA from the PubChem database. MTT assay and colony formation assay were used to determine the anti-proliferation and cytotoxicity of BA using in vitro cell models. Hoechst 33258 staining was used to investigate the extent of apoptosis after BA treatment. Western blot and immunofluorescence experiments were used to evaluate apoptosis-related and autophagy-related proteins and molecular mechanisms. We demonstrated that BA significantly inhibited cell proliferation in HepG2 and SMMC-7721 hepatocellular carcinoma cells, but with little cytotoxicity effects on l-02 normal liver cells. We further determined that the hepatocellular carcinoma prevention effects of BA were closely correlated with apoptosis and autophagy. Furthermore, our data indicated that BA-induced autophagy has a protective effect against cancer cell proliferation and promotes cell apoptosis. Additionally, apoptosis and autophagy were induced by BA through suppression of the PI3K/AKT/mTOR signaling pathway. Collectively, our study provides experimental evidence that BA inhibits cell proliferation and induces cell apoptosis and autophagy via suppressing the PI3K/AKT/mTOR pathway. Additionally, BA is a safe and effective herbal medicine compound that can be used for the prevention of hepatocellular carcinoma growth, and may be a potential therapeutic strategy against hepatocellular carcinoma.

The circular RNA-NRIP1 plays oncogenic roles by targeting microRNA-505 in the renal carcinoma cell lines

We explored the roles and regulatory mechanisms of the circular RNA (circRNA) nuclear receptor-interacting protein 1 (NRIP1; circNRIP1) in ACHN and CAKI-1 cells. ACHN and CAKI-1 cells were transfected with small-interfering-circNRIP1 (si-circNRIP1) and microRNA-505 (miR-505) inhibitor or the corresponding controls. Cell viability was detected with the Cell Counting Kit-8. The protein expression levels of Bcl-2, Bax, cleaved-caspase-3, matrix metalloproteinase (MMP)-2, MMP-9, adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), protein kinase B (AKT), phosphatidylinositol 3-kinase (PI3K), and mammalian target of rapamycin (mTOR) were individually determined via Western blot. Quantitative reverse transcription polymerase chain reaction was used to examine the expressions of circNRIP1 and miR-505 both in tumor cells and tissues. The apoptotic rate, the colony numbers, and the migration rate were separately determined by the Annexin V-fluorescein isothiocyanate/propidium iodide and flow cytometer, colony formation assay, and migration assay. We found that circNRIP1 was overexpressed in tumor tissue but miR-505 was overproduced. Silencing circZNF292 induced inhibition of cell viability, colony formation, and migration, as well as the activity of AMPK and PI3K/AKT/mTOR cascades but enhancement of apoptosis. si-circNRIP1 stimulated the upregulation of miR-505, whose silence abolished the effects of si-circNRIP1 on these elements mentioned above. In conclusion, the circNRIP1 played oncogenic roles in the ACHN and the CAKI-1 cell lines by targeting miR-505 via stimulating AMPK and PI3K/AKT/mTOR cascades.