DENV-2 NS1 promotes AMPK-LKB1 interaction to activate AMPK/ERK/mTOR signaling pathway to induce autophagy.

The global incidence of dengue fever has gradually increased in recent years, posing a serious threat to human health. In the absence of specific anti-dengue drugs, understanding the interaction of Dengue virus (DENV) with the host is essential for the development of effective therapeutic measures. Autophagy is often activated during DENV infection to promote viral replication, but the mechanism of how DENV's own proteins induce autophagy has not been clarified. In this study, we first preliminarily identified DENV-2 NS1 as the most likely viral protein for DENV-2-induced autophagy with the help of molecular docking techniques. Further experimental results confirmed that DENV-2 NS1 regulates DENV-2 infection of HUVEC-induced autophagy through the AMPK/ERK/mTOR signaling pathway. Mechanistically, DENV-2 NS1 mainly interacted with AMPK by means of its Wing structural domain, and NS1 bound to all three structural domains on the AMPKα subunit. Finally, the experimental results showed that DENV-2 NS1 promoted the interaction between LKB1 and AMPKα1 and thus activated AMPK by both increasing the expression of LKB1 and binding LKB1. In conclusion, the results of this study revealed that DENV-2 NS1 protein served as a platform for the interaction between AMPK and LKB1 after DENV-2 infection with HUVEC, and pulled AMPK and LKB1 together to form a complex. LKB1 to form a complex, promoting LKB1 action on the kinase structural domain of AMPKα1, which in turn promotes phosphorylation of the Thr172 site on the AMPK kinase structural domain and activates AMPK, thereby positively regulating the AMPK/ERK/mTOR signaling pathway and inducing autophagy. The present discovery improves our understanding of DENV-2-induced host autophagy and contributes to the development of anti-dengue drugs.

The protective effect of puerarin-loaded mesoporous silicon nanoparticles on alcoholic hepatitis through mTOR-mediated autophagy pathway.

Puerarin, a bioactive flavone compound isolated from Pueraria (Wild.), provides hepatoprotection by anti-inflammatory, anti-alcoholism, and regulating mechanistic target of rapamycin (mTOR). Building evidence suggests that the activation of mTOR reduces liver injuries associated with alcohol consumption and metabolism. However, the poor water solubility, low bioavailability, and short half-life of puerarin hinder its clinical application. The utility of mesoporous silicon nanoparticles (MSNs) can improve traditional Chinese medicine limitations. Stober methods were used to fabricate MSNs@Pue, and the size, zeta potentials and drug encapsulation efficiency were characterized by a series of analytical methods. IVIS Imaging System demonstrated liver-targeted bio-distribution, and then high-throughput sequencing, immunoproteomics and ultrastructure methods indicated autophagy related protective mechanism, followed by curative effect evaluation for the treatment efficacy. An acute-on chronic ethanol-drinking according to Gao-binge model induced alcoholic hepatitis (AH) pathology and resulted in hepatic hyper-autophagy, which was improved with MSNs@Pue administration (puerarin: 30 mM, 42 mg/kg; intravenously [i.v.]). Ethanol-fed mice were found to have increased expression of autophagy-related proteins (Atg3, Atg7, LC3 and p62). In contrast, MSNs@Pue administration significantly decreased the expression of these proteins and alleviated fatty droplets infiltration in damaged liver. Furthermore, acute-on-chronic ethanol feeding also resulted in the activiation of ERK activation and mTOR expression, which were reversed with MSNs@Pue administration and better than the usage of puerarin alone. Results point to MSNs@Pue mediated ERK/mTOR signaling pathway activation as a possible protective strategy to improve AH, which provides a strategy and evidence for treating liver disease using an MSN delivery system.

Mechanism of autophagy induced by activation of the AMPK/ERK/mTOR signaling pathway after TRIM22-mediated DENV-2 infection of HUVECs.

BACKGROUND: Dengue virus type 2 (DENV-2) was used to infect primary human umbilical vein endothelial cells (HUVECs) to examine autophagy induced by activation of the adenosine monophosphate-activated protein kinase (AMPK)/extracellular signal-regulated kinase (ERK)/mammalian target of rapamycin (mTOR) signaling pathway following tripartite motif-containing 22 (TRIM22)-mediated DENV-2 infection to further reveal the underlying pathogenic mechanism of DENV-2 infection. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to screen putative interference targets of TRIM22 and determine the knockdown efficiency. The effect of TRIM22 knockdown on HUVEC proliferation was determined using the CCK8 assay. Following TRIM22 knockdown, transmission electron microscopy (TEM) was used to determine the ultrastructure of HUVEC autophagosomes and expression of HUVEC autophagy and AMPK pathway-related genes were measured by qRT-PCR. Moreover, HUVEC autophagy and AMPK pathway-related protein expression levels were determined by western blot analysis. Cell cycle and apoptosis were assessed by flow cytometry (FCM) and the autophagosome structure of the HUVECs was observed by TEM. RESULTS: Western blot results indicated that TRIM22 protein expression levels increased significantly 36 h after DENV-2 infection, which was consistent with the proteomics prediction. The CCK8 assay revealed that HUVEC proliferation was reduced following TRIM22 knockdown (P < 0.001). The TEM results indicated that HUVEC autolysosomes increased and autophagy was inhibited after TRIM22 knockdown. The qRT-PCR results revealed that after TRIM22 knockdown, the expression levels of antithymocyte globulin 7 (ATG7), antithymocyte globulin 5 (ATG5), Beclin1, ERK, and mTOR genes decreased (P < 0.01); however, the expression of AMPK genes (P < 0.05) and P62 genes (P < 0.001) increased. FCM revealed that following TRIM22 knockdown, the percentage of HUVECs in the G2 phase increased (P < 0.001) along with cell apoptosis. The effect of TRIM22 overexpression on HUVEC autophagy induced by DENV-2 infection and AMPK pathways decreased after adding an autophagy inhibitor. CONCLUSIONS: In HUVECs, TRIM22 protein positively regulates autophagy and may affect autophagy through the AMPK/ERK/mTOR signaling pathway. Autophagy is induced by activation of the AMPK/ERK/mTOR signaling pathway following TRIM22-mediated DENV-2 infection of HUVECs.

Human Papillomavirus 11 Early Protein E6 Activates Autophagy by Repressing AKT/mTOR and Erk/mTOR.

Low-risk human papillomaviruses (LR-HPVs) are the causative agents of genital warts, which are a widespread sexually transmitted disease. How LR-HPVs affect autophagy and the specific proteins involved are unknown. In the current study, we investigated the impact of LR-HPV11 early protein 6 (E6) on the activity of the autophagy pathway. We transfected an HPV11 E6 (11E6) plasmid into HaCaT cells, H8 cells, and NHEK cells and established a stable cell line expressing the HPV11 E6 protein. The differences in autophagy activity and upstream regulatory pathways compared with those in the parent cell lines were investigated using a Western blot analysis of the total and phosphorylated protein levels and confocal microscopy of immunostained cells and cells transfected with an mCherry-green fluorescent protein-LC3 expression plasmid. We used short hairpin RNA (shRNA) to knock down 11E6 and showed that these effects require continued 11E6 expression. Compared with its expression in the control cells, the expression of HPV11 E6 in the cells activated the autophagy pathway. The increased autophagy activity was the result of the decreased phosphorylation levels of the canonical autophagy repressor mammalian target of rapamycin (mTOR) at its Ser2448 position (the mTOR complex 1 [mTORC1] phosphorylation site) and decreased AKT and Erk phosphorylation. Therefore, these results indicate that HPV11 E6 activates autophagy through the AKT/mTOR and Erk/mTOR pathways. Our findings provide novel insight into the relationship between LR-HPV infections and autophagy and could help elucidate the pathogenic mechanisms of LR-HPV.IMPORTANCE We transfected an HPV11 E6 plasmid into HaCaT cells, H8 cells, and NHEK cells and established a stable cell line expressing the HPV11 E6 protein. Then, we confirmed that HPV11 E6 induces autophagy by suppressing the AKT/mTOR and Erk/mTOR pathways. In contrast to the high-risk HPV E6 genes, HPV11 E6 did not affect the expression of p53. To the best of our knowledge, this study represents the first direct in-depth investigation of the relationship between the LR-HPV E6 gene and autophagy, which may help to reveal the pathogenesis of LR-HPV infection.

Aß40 modulates GABA(A) receptor α6 subunit expression and rat cerebellar granule neuron maturation through the ERK/mTOR pathway.

In addition to their neurotoxic role in Alzheimer's disease (AD), ß-amyloid peptides (Aßs) are also known to play physiological roles. Here, we show that recombinant Aß40 significantly increased the outward current of the GABA(A) receptor containing (GABA(A)α6) in rat cerebellar granule neurons (CGNs). The Aß40-mediated increase in GABA(A)α6 current was mediated by an increase in GABA(A)α6 protein expression at the translational rather than the transcriptional level. The exposure of CGNs to Aß40 markedly induced the phosphorylation of ERK (pERK) and mammalian target of rapamycin (pmTOR). The increase in GABA(A)α6 current and expression was attenuated by specific inhibitors of ERK or mTOR, suggesting that the ERK and mTOR signaling pathways are required for the effect of Aß40 on GABA(A)α6 current and expression in CGNs. A pharmacological blockade of the p75 neurotrophin receptor (p75(NTR)), but not the insulin or α7-nAChR receptors, abrogated the effect of Aß40 on GABA(A)α6 protein expression and current. Furthermore, the expression of GABA(A)α6 was lower in CGNs from APP(-/-) mice than in CGNs from wild-type mice. Moreover, the internal granule layer (IGL) in APP(-/-) mice was thinner than the IGL in wild-type mice. The injection of Aß40 into the cerebellum reversed this effect, and the application of p75(NTR) blocking antibody abolished the effects of Aß40 on cerebellum morphology in APP(-/-) mice. Our results suggest that low concentrations of Aß40 play a role in regulating CGN maturation through p75(NTR).

FABP4 Regulates Cell Proliferation, Stemness, Apoptosis, and Glycolysis in Colorectal Cancer via Modulating ROS/ERK/mTOR Pathway.

BACKGROUND: Colorectal cancer is a common digestive tract malignancy. This study aimed to expound the functional role of fatty-acid-binding protein 4 (FABP4) and the potential underlying mechanisms in the development of colorectal cancer. METHODS: Several techniques were utilized to investigate the role of FABP4 in colorectal cancer. FABP4 mRNA expression was quantified using Real time-quantitative PCR (RT-qPCR). Cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), sphere formation assays and flow cytometry evaluated cell growth, stemness, and apoptosis in SW480 and HT29 cells. Glycolysis was assessed via extracellular acidification rate (ECAR) , lactate production, glucose uptake, adenosine triphosphate (ATP)/adenosine 5'-diphosphate (ADP) ratio, and Glut1 and Elevated lactate dehydrogenase A (LDHA) protein expression. Reactive oxygen species (ROS) levels were analyzed by flow cytometry. Western blot measured the protein expression of FABP4, Proliferating cell nuclear antigen (PCNA), Bax, Bcl-2, Glut1, LDHA, stemness makers (Sox2, Oct4, and ALDHA1), and extracellular regulated protein kinase (ERK)/mammalian target of rapamycin (mTOR) pathway proteins. In vivo experiments, BALB/c nude mice (n = 12) were inoculated with 200 µL HT29 cells (5 × 106 cells) transfected with sh-FABP4 or short hairpin (sh)-negative control (NC), forming two groups with 6 mice each. The in vivo mice tumor model allowed for evaluating FABP4's impact on tumor growth. RESULTS: FABP4 was significantly upregulated in colorectal cancer tissues and cells (p < 0.05). FABP4 knockdown markedly inhibited cell proliferation, stemness, and glycolysis, while promoting apoptosis in these cells (p < 0.05). Additionally, FABP4 depletion led to a significant increase in ROS level (p < 0.05). However, N-acetyl-L-cysteine (NAC) (p < 0.05), a ROS scavenger, mitigates these effects. Furthermore, the effects of FABP4 depletion on cell growth, stemness, glycolysis, and apoptosis in colorectal cancer cells were also retarded by NAC (p < 0.05). Notably, FABP4 knockdown also suppressed the ERK/mTOR pathway, suggesting its regulation via ROS (p < 0.05). In vivo study results showed, FABP4 depletion significantly curbed tumor growth in colorectal cancer (p < 0.05). CONCLUSIONS: These results suggest that FABP4 depletion inhibits colorectal cancer progression by modulating cell growth, stemness, glycolysis and apoptosis. This regulation occurs through the ROS/ERK/mTOR pathway.

Cross-talk between the RAS-ERK and mTOR signalings-associated autophagy contributes to tripterygium glycosides tablet-induced liver injury.

BACKGROUND AND AIMS: Drug-induced liver injury (DILI) remains a critical issue and a hindrance to clinical application of Tripterygium Glycosides Tablet (TGT) despite its favorable therapeutic efficacy in rheumatoid arthritis. Herein, we aimed to elucidate the molecular mechanisms underlying TGT-induced hepatotoxicity. METHODS: Chemical profiling of TGT was identified by UPLC-Q/TOF-MS/MS and its putative targets were predicted based on chemical structure similarity calculation. Following "DILI-related gene-TGT putative target" interaction network construction, a list of key network targets was screened according to nodes' topological importance and functional relevance. Both in vivo and in vitro experiments were performed to determine drug hepatotoxicity and the underlying mechanisms. RESULT: A total of 49 chemical components and 914 putative targets of TGTs were identified. Network calculation and functional modularization screened RAS-ERK and mTOR signalings-associated autophagy to be one of the candidate targets of TGT-induced hepatotoxicity. Experimentally, TGT significantly activated RAS-ERK axis, elevated the number of autophagosomes and the expression of LC3II protein, but reduced the expression of p62 protein and suppressed mTOR phosphorylation in the liver tissues of TGT-induced acute liver injury mice and chronic liver injury mice in vivo and AML12 cells in vitro. Moreover, TGT and mL-098 (an activator of RAS) co-treatment reduced AML12 cell viability via regulating autophagy and TGT-induced liver injury-related indicators more dramatically than TGT treatment alone, whereas Salirasib (an inhibitor of RAS) had an opposite effect. CONCLUSION: RAS-ERK-mTOR cross-talk may play a crucial role in TGT-induced hepatocyte autophagy, offering a promising target for developing novel therapeutics to combat TGT-induced hepatotoxicity.

Cuban Policosanol Prevents the Apoptosis and the Mitochondrial Dysfunction Induced by Lipopolysaccharide in C2C12 Myoblast via Activation of Akt and Erk Pathways.

Skeletal muscle plays crucial roles in locomotion, protein reservoir, and maintenance of metabolic homeostasis. Loss of muscle, known as muscle atrophy, causes the metabolic diseases such as type 2 diabetes mellitus, hypertension, and so on. Therefore, great efforts have been devoted to prevent the muscle atrophy. Policosanols are a mixture of long chain fatty alcohols extracted from various natural sources. They have long been used as functional foods to lower the level of serum lipids, including triacylglycerol and cholesterol, and to protect against inflammatory stress. In this study, we examine the protective effect and molecular mechanism of Cuban policosanol on skeletal muscle cell death and mitochondrial dysfunction using lipopolysaccharide-treated C2C12 cells. Our results demonstrated that policosanol significantly rescued cell survival (40% vs. 88%; LPS vs. LPS+policosanol) via activation of the Akt pathway, resulting in inhibition of apoptosis (p<0.05). Moreover, policosanol restored the LPS-induced repression of collagen by two fold (0.33±0.04 vs. 0.67±0.03 compared to that of control; LPS vs. LPS+policosanol) via activation of ERK-mTOR-p70S6K pathways. In addition, policosanol increased the mitochondrial fusion by regulating the activities of DRP1 and Mfn2, leading to ameliorate the mitochondrial dysfunction induced by LPS. Improved mitochondria function increased the oxygen consumption rate with glucose as fuel source, indicating that policosanol could shift the glucose metabolism from lactate fermentation, induced by lipopolysaccharide, to oxidative phosphorylation. Thus, policosanol is a promising agent for preventing the inflammation-induced muscle cell death and mitochondrial dysfunction.

Intermittent Theta Burst Stimulation Ameliorates Cognitive Deficit and Attenuates Neuroinflammation via PI3K/Akt/mTOR Signaling Pathway in Alzheimer's-Like Disease Model.

Neurodegeneration implies progressive neuronal loss and neuroinflammation further contributing to pathology progression. It is a feature of many neurological disorders, most common being Alzheimer's disease (AD). Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive stimulation which modulates excitability of stimulated brain areas through magnetic pulses. Numerous studies indicated beneficial effect of rTMS in several neurological diseases, including AD, however, exact mechanism are yet to be elucidated. We aimed to evaluate the effect of intermittent theta burst stimulation (iTBS), an rTMS paradigm, on behavioral, neurochemical and molecular level in trimethyltin (TMT)-induced Alzheimer's-like disease model. TMT acts as a neurotoxic agent targeting hippocampus causing cognitive impairment and neuroinflammation, replicating behavioral and molecular aspects of AD. Male Wistar rats were divided into four experimental groups-controls, rats subjected to a single dose of TMT (8 mg/kg), TMT rats subjected to iTBS two times per day for 15 days and TMT sham group. After 3 weeks, we examined exploratory behavior and memory, histopathological and changes on molecular level. TMT-treated rats exhibited severe and cognitive deficit. iTBS-treated animals showed improved cognition. iTBS reduced TMT-induced inflammation and increased anti-inflammatory molecules. We examined PI3K/Akt/mTOR signaling pathway which is involved in regulation of apoptosis, cell growth and learning and memory. We found significant downregulation of phosphorylated forms of Akt and mTOR in TMT-intoxicated animals, which were reverted following iTBS stimulation. Application of iTBS produces beneficial effects on cognition in of rats with TMT-induced hippocampal neurodegeneration and that effect could be mediated via PI3K/Akt/mTOR signaling pathway, which could candidate this protocol as a potential therapeutic approach in neurodegenerative diseases such as AD.

Shengma Biejia Decoction Inhibits Cell Growth in Multiple Myeloma by Inducing Autophagy-Mediated Apoptosis Through the ERK/mTOR Pathway.

Shengma Biejia decoction (SMBJD), a traditional Chinese formula recorded in the Golden Chamber, has been widely used for the treatment of malignant tumors. However, its underlying molecular targets and mechanisms are still unclear. This study showed that SMBJD inhibited tumor growth and stimulated hemogram recovery significantly in a multiple myeloma xenograft model. Western blot and immunohistochemistry assays of tumor tissues showed that SMBJD reduced the ratio of autophagy-related proteins LC3-II/LC3-I, while P62 and apoptosis-related proteins cleaved caspase-3/caspase-3 and Bax/Bcl-2 were upregulated. In vitro experiments demonstrated the time-dependent and dose-dependent cytotoxicity of SMBJD on multiple myeloma cell lines H929 and U266 through MTT assays. The LC3-II/LC3-I ratio and number of GFP-LC3 puncta showed that SMBJD inhibited the autophagy process of H929 and U266 cells. Moreover, both SMBJD and 3-methyladenine (3-MA) caused a decrease in LC3-II/LC3-I, and SMBJD could not reverse the upregulation of LC3-II/LC3-I caused by bafilomycin A1 (Baf-A1). Furthermore, the results of annexin V-FITC and propidium iodide double staining demonstrated that SMBJD treatment induced the apoptosis of H929 and U266 cells. These data prove that SMBJD inhibits autophagy and promotes apoptosis in H929 and U266 cells. The results also show that rapamycin could reduce the rate of SMBJD-induced apoptosis in H929 and U266 cells, at a concentration which had no effect on apoptosis but activated autophagy. In addition, analysis of the mechanism indicated that levels of phosphorylated ERK and phosphorylated mTOR were increased by treatment with SMBJD in vivo and in vitro. These results indicate that SMBJD, an old and effective herbal compound, could inhibit the viability of H929 and U266 cells and induce autophagy-mediated apoptosis through the ERK/mTOR pathway. Thus, it represents a potential therapy strategy for multiple myeloma.

Dec2 attenuates autophagy in inflamed periodontal tissues.

INTRODUCTION: Transcriptional regulation of autophagy depends on the transcription factors coordinated inflammatory feedback mechanism. Here, we provide a comprehensive functional characterization of periodontal ligament fibroblasts (PDLFs) treated with Porphyromonas gingivalis lipopolysaccharide (LPS), aiming to reveal previously unappreciated biological changes and to investigate how a transcription factor differentiated embryonic chondrocytes 2 (Dec2)-deficient environment influences the function of autophagy in nflamed human PDLFs. METHODS: A Dec2-deficient (Dec2KO) experimental periodontal inflammation mouse model and treatment with P. gingivalis LPS were employed to examine the role of autophagy in PDLFs using hematoxylin and eosin staining and immunohistochemistry in vivo. A Dec2 small interfering RNA (siRNA) was used to modulate autophagy, and the effect of autophagy on the Dec2 pathway was explored using real-time polymerase chain reaction and western blot analysis in vitro. RESULTS: LPS-treated human PDLFs (HPDLFs) induced autophagy, as demonstrated by the enhanced levels of microtubule-associated protein 1 light chain 3-II (LC3-II) and the induction of ATG5, Beclin1, and Dec2. Compared with a scrambled siRNA, a Dec2 siRNA triggered the detrimental influences of LPS and markedly enhanced autophagy expression in inflamed HPDLFs. The expression of phosphorylated ERK was increased and levels of phosphorylated mammalian target of rapamycin (mTOR) were decreased after exposure to LPS in Dec2 siRNA transfected HPDLFs. The Dec2KO model exhibited that P. gingivalis in Dec2 deficient conditions increases the inflammation of PDLFs by regulating autophagy. CONCLUSIONS: These results demonstrate that a Dec2 deficiency can alleviate LPS-induced inflammation via the ERK/mTOR signaling pathway by regulating autophagy, conceivably delivering a novel approach for the detection of periodontal treatments.

Mesencephalic Astrocyte-Derived Neurotrophic Factor (MANF) Regulates Neurite Outgrowth Through the Activation of Akt/mTOR and Erk/mTOR Signaling Pathways.

Neurite outgrowth is essential for brain development and the recovery of brain injury and neurodegenerative diseases. In this study, we examined the role of the neurotrophic factor MANF in regulating neurite outgrowth. We generated MANF knockout (KO) neuro2a (N2a) cell lines using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 and demonstrated that MANF KO N2a cells failed to grow neurites in response to RA stimulation. Using MANF siRNA, this finding was confirmed in human SH-SY5Y neuronal cell line. Nevertheless, MANF overexpression by adenovirus transduction or addition of MANF into culture media facilitated the growth of longer neurites in RA-treated N2a cells. MANF deficiency resulted in inhibition of Akt, Erk, mTOR, and P70S6, and impaired protein synthesis. MANF overexpression on the other hand facilitated the growth of longer neurites by activating Akt, Erk, mTOR, and P70S6. Pharmacological blockade of Akt, Erk or mTOR eliminated the promoting effect of MANF on neurite outgrowth. These findings suggest that MANF positively regulated neurite outgrowth by activating Akt/mTOR and Erk/mTOR signaling pathways.

Tanshinone IIA induces autophagy in colon cancer cells through MEK/ERK/mTOR pathway.

BACKGROUND: Colon cancer is a common malignancy of the digestive tract. The search for effective drugs to treat colon cancer has become the focus of current researches. Tanshinone IIA (Tan IIA) is a fat-soluble component extracted from tanshinone, a traditional Chinese medicine. Tan IIA can modulate the occurrence and development of tumors, but its effect on autophagy in colon cancer cells has not been reported. METHODS: Two types of colon cancer cell lines were selected and different concentrations of Tan IIA were used to treat cells at different time points. Cell Counting Kit-8 assay (CCK-8) was used to detect the effect of Tan IIA on cell proliferation; transmission electron microscopy was used to observe the formation of autophagosomes; reverse transcription-polymerase chain reaction (RT-qPCR) and western blot were used to detect the expression of autophagy related genes and proteins. Cell transfection was used to interfere with MEK (mitogen-activated extracellular signal-regulated kinase) expression, and RT-qPCR and western blot were used to detect the expression of MEK/ERK/mTOR pathway-related proteins. RESULTS: Tan IIA resulted in a significant reduction in the viability of the two kinds of colon cancer cells. The number of autophagosomes increased significantly after the treatment of Tan IIA into these cells. Addition of autophagy inhibitor 3-MA (3-Methyladenine) improved the increase of autophagosomes in cells induced by Tan IIA. At the same time, Tan IIA induced the expression of autophagy-related proteins in the two colon cancer cell lines. When Tan IIA induced autophagy in colon cancer cells, the expression of MEK/ERK/mTOR pathway-related proteins increased significantly. After interfering with the expression of MEK, the expression of autophagy decreased significantly, indicating that Tan IIA promoted autophagy of colon cancer cells through MEK/ERK/mTOR pathway. CONCLUSIONS: Tan IIA stimulates autophagy in colon cancer cells through MEK/ERK/mTOR pathway, hence inhibiting the growth of colon cancer cells.

Perfluorooctanoic acid induces human Ishikawa endometrial cancer cell migration and invasion through activation of ERK/mTOR signaling.

Perfluorooctanoic acid (PFOA) is a common environmental pollutant that has been associated with various diseases, including cancer. We explored the molecular mechanisms underlying PFOA-induced endometrial cancer cell invasion and migration. PFOA treatment enhanced migration and invasion by human Ishikawa endometrial cancer cells, which correlated with decreased E-cadherin expression, a marker of epithelial-mesenchymal transition. PFOA also induced activation of ERK1/2/mTOR signaling. Treatment with rapamycin, an mTOR inhibitor, antagonized the effects of PFOA and reversed the effects of PFOA activation in a xenograft mouse model of endometrial cancer. Consistent with these results, pre-treatment with rapamycin abolished PFOA-induced down-regulation of E-cadherin expression. These results indicate that PFOA is a carcinogen that promotes endometrial cancer cell migration and invasion through activation of ERK/mTOR signaling.