Curcumin inhibited HGF-induced EMT and angiogenesis through regulating c-Met dependent PI3K/Akt/mTOR signaling pathways in lung cancer

Effect of curcumin on vascular endothelial growth factor in hypoxic HepG2 cells via the insulin-like growth factor 1 receptor signaling pathway

To investigate the anti-angiogenic effect and underlying molecular mechanisms of curcumin on HepG2 cells under hypoxic conditions, insulin-like growth factor 1 receptor (IGF-1R) knockout HepG2 cells were constructed using a clustered regularly interspaced short palindromic repeats/Cas9 genome-editing system. Hypoxic conditions were generated using cobalt chloride (CoCl₂). An MTT assay was performed to measure the effects of curcumin on cell viability in hypoxia-induced IGF-1R knockout HepG2 cells, while western blot analysis was used to detect the expression of IGF-1R, phosphorylated (p)-protein kinase B (Akt), p-extracellular signal-regulated kinases (Erk)1/2, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). The results revealed that CoCl₂ at low concentrations (50 and 100 µM) had no significant inhibitory effects on IGF-1R knockout HepG2 cells. However, with increasing concentrations of CoCl₂ and treatment time, cell viability decreased and was significantly reduced at 150, 200 and 400 µM compared with the control group (P<0.05). The expression of HIF-1α and VEGF were significantly increased when the cells were treated with 150 or 200 µM CoCl₂ compared with the control (P<0.05). With the increase of CoCl₂ concentration or the treatment time, the expression of HIF-1α and VEGF were upregulated gradually. Additionally, curcumin significantly inhibited the expression of p-Akt, p-Erk1/2, HIF-1α and VEGF in hypoxia-induced IGF-1R knockout HepG2 cells. In conclusion, the findings of the present study suggest that curcumin may serve a pivotal role in tumor suppression via the inhibition of IGF-1R-mediated angiogenesis under hypoxic conditions.

Curcumin inhibits hepatocellular carcinoma growth by targeting VEGF expression

Morbidity and mortality owing to hepatocellular carcinoma (HCC), the most common primary liver cancer, has increased in recent years. Curcumin is a polyphenol compound that has been demonstrated to exert effective antiangiogenic, anti-inflammatory, antioxidant, and antitumor effects. However, its clinical effects in HCC remain elusive. The main aim of the present study was to determine the antiangiogenic effects of curcumin in HCC. H22HCC cells were treated with different concentrations of curcumin in vitro. In addition, a mouse xenograft model was used and analyzed for expression levels of vascular endothelial growth factor (VEGF) protein and proteins of the phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase 1 (AKT) signaling pathway. Curcumin treatment inhibited H22 cell proliferation and promoted H22 cell apoptosis in a dose-dependent manner in vitro. In addition, curcumin treatment inhibited tumor growth in vivo at the concentrations of 50 and 100 mg/kg. Furthermore, curcumin treatment significantly decreased VEGF expression and PI3K/AKT signaling. The present findings demonstrated that curcumin inhibited HCC proliferation in vitro and in vivo by reducing VEGF expression.

Curcumin inhibits the growth of liver cancer stem cells through the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway

Cancer stem cells are considered as a main cause of cancer recurrence. In the present study, the effects of curcumin on the growth of liver cancer stem cells (LCSCs) were investigated. The proliferation and apoptosis of LCSCs were assessed by MTT assays and flow cytometry. Changes in the expression of apoptosis-related proteins were identified by western blotting. The results of the study demonstrated that curcumin treatment inhibited the growth of LCSCs, induced cell apoptosis, as well as regulated the expression of apoptosis-associated proteins and the release of cytochrome c. Further experiments revealed that treatment with curcumin inhibited that the activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. Treatment with an activator of PI3K/AKT reversed the curcumin-induced growth inhibition of LCSCs. These results demonstrated that curcumin inhibited the growth of LCSCs through the PI3K/AKT/mTOR signaling pathway. Thus, the present study suggested that curcumin may be a potentially efficient agent in the treatment of liver cancer.

Antifibrotic Effects of Hepatocyte Growth Factor on Endothelial-to-Mesenchymal Transition via Transforming Growth Factor-Beta1 (TGF-β1)/Smad and Akt/mTOR/P70S6K Signaling Pathways

Background

The related mechanisms involved in allograft interstitial fibrosis and chronic allograft dysfunction (CAD), following renal transplant, remain largely unknown. Here, we explored the role of hepatocyte growth factor (HGF) treatment on the endothelial-to-mesenchymal transition (EndMT) as a new way to target and prevent kidney fibrosis and improve outcomes for renal transplant recipients.

Method/Material

We extracted proteins and mRNAs from human umbilical vein endothelial cells (HUVECs) and human renal glomerular endothelial cells (HRGECs) treated with transforming growth factor-beta1 (TGF-β1) and/or varying doses of HGF, and assessed the effect of HGF on the EndMT using western blotting, qRT-PCR, and ELISA assays. We utilized cell motility and migration assays to evaluate cell movement, and applied western blotting to assess the mechanism by which TGF-β1 induced the EndMT.

Results

HGF significantly attenuated the development of TGF-β1-induced EndMT in a concentration-dependent way, and weakened the abilities of motility and migration of both HUVECs and HRGECs. Moreover, our results reveal that the antifibrotic effect of HGF on the EndMT was associated with the TGF-β/Smad and Akt/mTOR/p70S6K signaling pathways.

Conclusions

Our study suggests that HGF treatment significantly attenuates the development of EndMT induced by TGF-β1 via the TGFβ/Smad and Akt/mTOR/P70S6K signaling, which provides novel insights into the prevention and treatment of interstitial fibrosis and CAD following renal transplant.

Phytochemicals and PI3K Inhibitors in Cancer-An Insight

In today's world of modern medicine and novel therapies, cancer still remains to be one of the prime contributor to the death of people worldwide. The modern therapies improve condition of cancer patients and are effective in early stages of cancer but the advanced metastasized stage of cancer remains untreatable. Also most of the cancer therapies are expensive and are associated with adverse side effects. Thus, considering the current status of cancer treatment there is scope to search for efficient therapies which are cost-effective and are associated with lesser and milder side effects. Phytochemicals have been utilized for many decades to prevent and cure various ailments and current evidences indicate use of phytochemicals as an effective treatment for cancer. Hyperactivation of phosphoinositide 3-kinase (PI3K) signaling cascades is a common phenomenon in most types of cancers. Thus, natural substances targeting PI3K pathway can be of great therapeutic potential in the treatment of cancer patients. This chapter summarizes the updated research on plant-derived substances targeting PI3K pathway and the current status of their preclinical studies and clinical trials.

Human lung epithelial cells A549 epithelial-mesenchymal transition induced by PVA/Collagen nanofiber

Epithelial-mesenchymal transition (EMT) is a process by which epithelial cells lose their cell-cell contact to become mesenchymal stem cells, which is important on development and embryogenesis, wound healing, and cancer metastasis. This research aims to investigate the effect of topological cue as modulating factor on the EMT by tuning the diameter of electrospinning nanofiber. The cell-nanofiber interaction between human lung epithelial cell A549 and electrospinning nanofibers composed of polyvinyl alcohol (PVA) and type I collagen were investigated. The electrospinning of regenerated PVA/Collagen nanofibers were performed with water/acetic acid as a spinning solvent and glutaraldehyde as a chemical cross-linker. Parameterization on concentration, applied voltage and feeding rate was finalized to generate smooth nanofibers with good homogeneity. The scanning electron microscopy result demonstrated that A549 cell appropriately achieved extended morphology by the filopodia attaching to the surface of the nanofibrous mats. When the diameter changed from 90nm to 240nm, the A549 cell was correspondingly express varied EMT related genes. Gene expression analysis was conducted by qPCR using three typical markers for detecting EMT: N-cadherin (NCad), Vimentin (Vim), and Fibronectin (Fib). An increasing expression pattern was observed on cell culturing on 170nm sample with respect to cell cultured on 90nm and 240nm. This result indicated the 170nm PVA/Collagen nanofibers induce A549 cells to process epithelial-mesenchymal transition more seriously than those on 90nm or 240nm.

Quercetin reverses the doxorubicin resistance of prostate cancer cells by downregulating the expression of c-met

Chemotherapy is an irreplaceable treatment for prostate cancer. However, the acquisition of chemoresistance is a common and critical problem that requires urgent solutions for the effective treatment of this disease. The aim of the present study was to determine whether the combination of quercetin with doxorubicin reversed the resistance of prostate cancer cells to doxorubicin-based therapy. A prostate cancer (PC)3 cell line (PC3/R) with acquired doxorubicin-resistance was established. A significant drug-resistance to doxorubicin and high activation of the phosphoinositide 3-kinase/protein kinase-B (PI3K/AKT) pathway in PC3/R cells, compared with normal PC3 cells, was demonstrated. Notably, combination treatment of doxorubicin with quercetin significantly promoted the doxorubicin-induced apoptosis in PC3/R cells through the mitochondrial/reaction oxygen species pathway. In PC3/R cells, a significant upregulation of tyrosine-protein kinase-met (c-met) was observed compared with nromal PC3 cells. However, the response to quercetin treatment in PC3/R cells inhibited c-met expression and the downstream PI3K/AKT pathway. In addition, induced expression of c-met rescued quercetin-promoted apoptosis in PC3/R cells treated with doxorubicin. The results of the present study indicated that quercetin is able to reverse prostate cancer cell doxorubicin resistance by downregulating the expression of c-met. It may represent a potential strategy for reversing the chemoresistance of prostate cancer.

DEK promoted EMT and angiogenesis through regulating PI3K/AKT/mTOR pathway in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer associated with poor prognosis. As an oncogene, DEK involves in regulation of various cellular metabolisms and plays an important role in tumor growth and progression. Increasing evidences suggested that abnormal expression of DEK is closely related to multiple malignant tumors. However, the possible involvement of DEK in epithelial to mesenchymal transition (EMT) and angiogenesis in TNBC remains unclear. In the present study, we revealed that the over-expression of DEK was significantly correlated with clinical stage, differentiation, and lymph node (LN) metastasis of TNBC and indicated poor overall survival of TNBC patients. Moreover, we demonstrated that DEK depletion could significantly reduce cell proliferation, migration, invasion and angiogenesis in vitro. We also found that DEK promoted cancer cell angiogenesis and metastasis by activating the PI3K/AKT/mTOR pathway. Furthermore, we revealed the inhibitory effect of DEK depletion on tumor growth and progression in a xenograft tumor model in mice. These data indicated that DEK promotes TNBC cell proliferation, angiogenesis, and metastasis via PI3K/AKT/mTOR signaling pathway, and therefore, it might be a potential target in TNBC therapy.

Curcumin potentiates the potent antitumor activity of ACNU against glioblastoma by suppressing the PI3K/AKT and NF-κB/COX-2 signaling pathways

Glioblastoma (GBM) is a highly invasive and challenging primary tumor of the central nervous system (CNS), and currently available treatments provide limited benefits to patients with this disease. Therefore, the development of novel therapeutic targets and effective treatment strategies is essential. Nimustine hydrochloride (ACNU) is widely used as the standard chemotherapeutic agent and is frequently administered together with other chemotherapeutic agents in clinical studies. Curcumin, a natural polyphenolic compound, could potentially be combined with chemotherapeutics for cancer treatment; however, there are no reports of studies where ACNU and curcumin were combined for GBM treatment, and the mechanisms underlying their activity remain poorly understood. In the present study, we investigated the effects of combined treatment with curcumin and ACNU on GBM cells and found that it significantly enhanced the inhibition of cell proliferation, colony formation, migration, and invasion. In addition, co-treatment with curcumin increased ACNU-induced apoptosis through enhancing the release of cytochrome c from the mitochondrial intermembrane space into the cytosol. Further, curcumin and ACNU acted synergistically in their antitumor effects by targeting N-cadherin/MMP2/9, PI3K/AKT, and NF-κB/COX-2 signaling. These results indicate that curcumin can enhance the anti-proliferation, anti-migration, and proapoptotic activities of ACNU against GBM, and provide strong evidence that combined treatment with curcumin and ACNU has the potential to be an effective therapeutic option for GBM.

Prospects for new lung cancer treatments that target EMT signaling

Lung cancer is the most common cancer worldwide. Treatment options for lung cancer include surgery, radiation therapy, chemotherapy, molecularly targeted therapy including epidermal growth factor receptor or anaplastic lymphoma kinase inhibitors, and immunotherapy. These treatments can be administered alone or in combination. Despite therapeutic advances, however, lung cancer remains the leading cause of cancer death. Recent studies have indicated that epithelial-mesenchymal transition (EMT) is associated with malignancy in various types of cancer, and activation of EMT signaling in cancer cells is widely considered to contribute to metastasis, recurrence, or therapeutic resistance. In this review, we provide an overview of the role of EMT in the progression of lung cancer. We also discuss the prospects for new therapeutic strategies that target EMT signaling in lung cancer. Developmental Dynamics 247:462-472, 2018. © 2017 Wiley Periodicals, Inc.

Material-induced Senescence (MIS): Fluidity Induces Senescent Type Cell Death of Lung Cancer Cells via Insulin-Like Growth Factor Binding Protein 5

Objective: We propose here material-induced senescence (MIS) as a new therapeutic concept that limits cancer progression by stable cell cycle arrest. This study examined for the first time the effect of material fluidity on cellular senescence in lung carcinoma using poly(ε-caprolactone-co-D, L-lactide) (P(CL-co-DLLA)) with tunable elasticity and fluidity. Methods: The fluidity was varied by chemically crosslinking the polymer networks: the crosslinked P(CL-co-DLLA) shows solid-like properties with a stiffness of 260 kPa, while the non-crosslinked polymer exists in a quasi-liquid state with loss and storage moduli of 33 kPa and 11 kPa, respectively. Results: We found that cancer cells growing on the non-crosslinked, fluidic substrate undergo a non-apoptotic form of cell death and the cell cycle was accumulated in a G0/G1 phase. Next, we investigated the expression of biomarkers that are associated with cancer pathways. The cancer cells on the fluidic substrate expressed several biomarkers associated with senescence such as insulin-like growth factor binding protein 5 (IGFBP5). This result indicates that when cancer cells sense fluidity in their surroundings, the cells express IGFBP5, which in turn triggers the expression of tumor suppressor protein 53 and initiates cell cycle arrest at the G1 phase followed by cellular senescence. Furthermore, the cancer cells on the fluidic substrate maintained their epithelial phenotype, suggesting that the cancer cells do not undergo epithelial to mesenchymal transition. Conclusion: By considering these results as the fundamental information for MIS, our system could be applied to induce senescence in treatment-resistant cancers such as metastatic cancer or cancer stem cells.

Recent progress on the effects of microRNAs and natural products on tumor epithelial-mesenchymal transition

Epithelial–mesenchymal transition (EMT) is a biological process of phenotypic transition of epithelial cells that can promote physiological development as well as tissue healing and repair. In recent years, cancer researchers have noted that EMT is closely related to the occurrence and development of tumors. When tumor cells undergo EMT, they can develop enhanced migration and local tissue invasion abilities, which can lead to metastatic growth. Nevertheless, two researches in NATURE deny its necessity in specific tumors and that is discussed in this review. The degree of EMT and the detection of EMT-associated marker molecules can also be used to judge the risk of metastasis and to evaluate patients’ prognosis. MicroRNAs (miRNAs) are noncoding small RNAs, which can inhibit gene expression and protein translation through specific binding with the 3′ untranslated region of mRNA. In this review, we summarize the miRNAs that are reported to influence EMT through transcription factors such as ZEB, SNAIL, and TWIST, as well as some natural products that regulate EMT in tumors. Moreover, mutual inhibition occurs between some transcription factors and miRNAs, and these effects appear to occur in a complex regulatory network. Thus, understanding the role of miRNAs in EMT and tumor growth may lead to new treatments for malignancies. Natural products can also be combined with conventional chemotherapy to enhance curative effects.

Role of matrix metalloproteinase-9 in transforming growth factor-β1-induced epithelial-mesenchymal transition in esophageal squamous cell carcinoma

Epithelial–mesenchymal transition (EMT) is thought to be a crucial event during the early metastasis of tumor cells. Transforming growth factor (TGF)-β1 is involved in the process of EMT in a variety of human malignancies. Matrix metalloproteinase (MMP)-9 plays an important role in tumor invasion and metastasis, and its expression is regulated by various growth factors, including TGF-β1, in different cell types. To date, the role of MMP-9 in TGF-β1-induced EMT in esophageal squamous cell carcinoma (ESCC) remains unclear. In this study, we aimed to elucidate the mechanism underlying MMP-9-mediated TGF-β1 induction of EMT in ESCC. We analyzed the expression of MMP-9, E-cadherin, and vimentin, in ESCC cells (EC-1), before and after the treatment with exogenous TGF-β1 or a broad spectrum MMP inhibitor, GM6001. Additionally, we analyzed the activity of MMP-9 in these cells and performed MMP-9 knockdown experiments. The results obtained in this study demonstrated that the treatment of EC-1 cells with TGF-β1 can induce EMT, together with the upregulation of vimentin and downregulation of E-cadherin expression in a time-dependent manner. The treatment with GM6001 was shown to attenuate TGF-β1-induced EMT. Furthermore, the exposure of EC-1 cells to TGF-β1 increased the expression and activity of MMP-9, while MMP-9 knockdown blocked TGF-β1-induced EMT and inhibited cell invasiveness and migration. Additionally, treatment with the recombinant human MMP-9 was shown to induce EMT and enhance ESCC cell invasion and metastasis. The obtained data suggest that the regulation of MMP-9 by TGF-β1 may represent a novel mechanism underlying TGF-β1-induced EMT in ESCC.

Electrospinning of PVA/sericin nanofiber and the effect on epithelial-mesenchymal transition of A549 cells

This research aims to investigate the cell-nanomaterial interaction between epithelial-mesenchymal transition of A549 cell and electrospinning nanofibers composed of polyvinyl alcohol (PVA)/silk sericin (SS). The electrospinning of regenerated nanofiber was performed with water as a spinning solvent and glutaraldehyde as a chemical cross-linker. Solution concentration, applied voltage and spin distances as well as other parameters were optimized to generate fine nanofibers with smooth surface in good homogeneity. From the scanning electron microscopy (SEM) analysis, the nanofibers had an average diameter of 200nm. Epithelial-mesenchymal transition (EMT) is a process by which epithelial cells lose their cell polarity to become mesenchymal stem cells. This transition is affected by multiple biochemical and physical factors in cell metabolism cascade. Herein, we investigate the biophysical effect on A549 EMT by culturing cells on nanofibrous mats with different topography and composition. The cell viability was evaluated by biochemical assay and its morphology was observed with SEM. The results demonstrate that cells appropriately attached to the surface of the nanofibrous mats with extended morphology by their filopodia. Gene expression analysis was conducted by real-time PCR using multiple markers for detecting EMT: N-cadherin (NCad), Vimentin (Vim), Fibronectin (Fib) and Matrix metallopeptidase (MMP9). An increasing expression pattern was observed on NCad, Vim, Fib, with respect to a negative control as cell cultured on polystyrene dish. This result indicates the 200nm PVA/SS nanofibers may induce A549 cells to process epithelial-mesenchymal transition during the culturing.

Curcumin increases efficiency of γ-irradiation in gliomas by inhibiting Hedgehog signaling pathway

It was reported that γ-irradiation had a controversial therapeutic effect on glioma cells. We aimed to investigate the cytotoxic effect on the glioma cells induced by γ-irradiation and explore the treatment to rescue the phenotype alteration of remaining cells. We used transwell assay to detect the glioma cell invasion and migration capacity. Cell proliferation and apoptosis were tested by the CCK-8 assay and flow cytometry respectively. Western Blot was used to detect the activity of Hedgehog signaling pathway and Epithelial-to-Mesenchymal Transition (EMT) status. γ-irradiation showed cytotoxic effect on LN229 cells in vitro, whereas this contribution was limited in U251 cells. However, it could significantly stimulated EMT process in both LN229 and U251. Curcumin (CCM) could rescue EMT process induced by γ-irradiation via the suppression of Gli1 and the upregulation of Sufu. The location and expression of EMT markers were also verified by Immunofluorescence. Immunohistochemistry assay was used on intracranial glioma tissues of nude mice. The capacities of cell migration and invasion were suppressed with combined therapy. This research showed Curcumin could rescue the EMT process induced by γ-irradiation via inhibiting the Hedgehog signaling pathway and potentiate the cell cytotoxic effect in vivo and in vitro.

Sirtuins, a promising target in slowing down the ageing process

Ageing is a plastic process and can be successfully modulated by some biomedical approaches or pharmaceutics. In this manner it is possible to delay or even prevent some age-related pathologies. There are some defined interventions, which give promising results in animal models or even in human studies, resulting in lifespan elongation or healthspan improvement. One of the most promising targets for anti-ageing approaches are proteins belonging to the sirtuin family. Sirtuins were originally discovered as transcription repressors in yeast, however, nowadays they are known to occur in bacteria and eukaryotes (including mammals). In humans the family consists of seven members (SIRT1-7) that possess either mono-ADP ribosyltransferase or deacetylase activity. It is believed that sirtuins play key role during cell response to a variety of stresses, such as oxidative or genotoxic stress and are crucial for cell metabolism. Although some data put in question direct involvement of sirtuins in extending human lifespan, it was documented that proper lifestyle including physical activity and diet can influence healthspan via increasing the level of sirtuins. The search for an activator of sirtuins is one of the most extensive and robust topic of research. Some hopes are put on natural compounds, including curcumin. In this review we summarize the involvement and usefulness of sirtuins in anti-ageing interventions and discuss the potential role of curcumin in sirtuins regulation.

Irisin suppresses the migration, proliferation, and invasion of lung cancer cells via inhibition of epithelial-to-mesenchymal transition

Irisin is involved in promoting metabolism, immune regulation, and affects chronic inflammation in many systemic diseases, including gastric cancer. However, the role of irisin in lung cancer is not well characterized. To determine whether irisin has a protective effect against lung cancer, we cultured A549 and NCI-H446 lung cancer cells and treated them with irisin. We detected the proliferation by MTT assay, and assessed the migration and invasion of the cells by scratch wound healing assay and Tran-swell assay. The expression levels of epithelial-to-mesenchymal transition (EMT) markers and the related signaling pathways were detected by western blot analysis. Meanwhile, an inhibitor of PI3K was used to investigate the effect of irsin. Finally, the expression of Snail was detected. We demonstrated that irisin inhibits the proliferation, migration, and invasion of lung cancer cells, and has a novel role in mediating the PI3K/AKT pathway in the cells. Irisin can reverse the activity of EMT and inhibit the expression of Snail via mediating the PI3K/AKT pathway, which is a key regulator of Snail. These results revealed that irisin inhibited EMT and reduced the invasion of lung cancer cells via the PI3K/AKT/Snail pathway.