Toxic effects induced by curcumin in human astrocytoma cell lines

Endoplasmic Reticulum Stress in Gliomas: Exploiting a Dual-Effect Dysfunction through Chemical Pharmaceutical Compounds and Natural Derivatives for Therapeutical Uses

The endoplasmic reticulum maintains proteostasis, which can be disrupted by oxidative stress, nutrient deprivation, hypoxia, lack of ATP, and toxicity caused by xenobiotic compounds, all of which can result in the accumulation of misfolded proteins. These stressors activate the unfolded protein response (UPR), which aims to restore proteostasis and avoid cell death. However, endoplasmic response-associated degradation (ERAD) is sometimes triggered to degrade the misfolded and unassembled proteins instead. If stress persists, cells activate three sensors: PERK, IRE-1, and ATF6. Glioma cells can use these sensors to remain unresponsive to chemotherapeutic treatments. In such cases, the activation of ATF4 via PERK and some proteins via IRE-1 can promote several types of cell death. The search for new antitumor compounds that can successfully and directly induce an endoplasmic reticulum stress response ranges from ligands to oxygen-dependent metabolic pathways in the cell capable of activating cell death pathways. Herein, we discuss the importance of the ER stress mechanism in glioma and likely therapeutic targets within the UPR pathway, as well as chemicals, pharmaceutical compounds, and natural derivatives of potential use against gliomas.

Curcumin Modulates the Membrane Raft Integrity via Phase Separation and Induces CD44 Shedding in Tumor Cells

CD44 is a transmembrane cell adhesion molecule that is cleaved by the membrane proteinase, a disintegrin and metalloproteinase 10 (ADAM10), on the cell surface via ectodomain shedding after cholesterol depletion. Lipid raft-mediated CD44 shedding is essential for cancer cell invasion. As cell-cell and cell-matrix adhesions are critical for cancer progression, lipid raft-targeting agents may be effective for cancer therapy. Here, we found that curcumin and its derivatives induced the ADAM10-mediated shedding of CD44 in tumor cells. We also found that curcumin and the derivatives are membrane-active compounds whose effect depends on its planar backbone and the spatial arrangement of methoxy groups substituted on the two aromatic rings using giant unilamellar and plasma membrane vesicles. Curcumin and its derivatives with rigid backbones and hydroxy groups exerted membrane-domain-modulating activity, which may account for their pleiotropic effects via multiple signaling pathways involving membrane receptors. This study provides a basis for the use of membrane-active compounds, such as curcuminoids, to elucidate the roles of lipid rafts in cellular signaling, regulation of membrane-bound ADAM metalloproteinases, and the development of novel membrane lipid-based therapies.

Spiropachysine A suppresses hepatocellular carcinoma proliferation by inducing methuosis in vitro and in vivo

BACKGROUND

Spiropachysine A is the extracted compound of traditional Chinese ethnic medicine Pachysandra axillaries Franch. var. styiosa (Dunn) M. Cheng. Spiropachysine A is the primary active steroidal alkaloids (SAs) widely used to facilitate blood circulation and relieve pain and inflammation. Few previous studies have investigated the anti-cancer activity of Spiropachysine A to treat hepatocellular carcinoma (HCC), and its molecular mechanism remains unknown.

PURPOSE

This study aims to investigate the anti-cancer activity of Spiropachysine A and the underlying mechanisms by inducing methuosis in vitro and in vivo.

METHODS

Here, the activity of Spiropachysine A against cancer was evaluated by the experiments with MHCC-97H cells and the xenografted mice model. The cell proliferation was examined using MTT assay, and cell morphological characteristics were observed by microscope cellular imaging. The effects of autophagy, paraptosis, and oncosis on cytoplasmic vacuolisation were detected using immunofluorescence staining, transmission electron microscopy (TEM) and western blotting (WB). The cell cycle distribution and apoptosis were analysed by flow cytometry. Hematoxylin eosin (H & E) staining was used to observe the pathological changes of the tissues.

RESULTS

The in vitro and in vivo results indicated that Spiropachysine A could inhibit HCC cells proliferation (IC₅₀ = 2.39 ± 0.21 μM against MHCC-97H cells) and tumor growth (TGI = 32.81 ± 0.23% at 25 mg/kg and 50.32 ± 0.26% at 50 mg/kg). The morphological changes of the treated cells showed that cell proliferation inhibition caused by Spiropachysine A was associated with numerous cytoplasmic vacuolization. Mechanistically, Spiropachysine A-induced methuosis rather than autophagy or arapaptic because the autophagy flux was blocked, leading to the increased LC3-II/I value and an accumulation of selective autophagy substrate p62. And, there was no activation of the regulatory parapaptic MAPK pathway. Additionally, the TEM and Lucifer yellow (LY) accumulation data confirmed that Spiropachysine A significantly triggered methuosis instead of oncosis. Further, the study indicated that the anti-proliferative activity of Spiropachysine A was independent of PCD since no alterations in apoptosis and cell cycle arrest-related proteins were observed after Spiropachysine A treatment. Impressively, the increased expression of Rac1 was observed in Spiropachysine A-treated MHCC-97H cells and its xenograft tumours, confirming that Spiropachysine A inhibited cell proliferation and induced methuosis through Ras/Rac1 signal pathways.

CONCLUSIONS

Spiropachysine A was collectively identified as a novel methuosis inducer that suppresses HCC in vitro and in vivo. The underlying mechanisms might be involved in the Ras/Rac1 pathway. Such data predict that Spiropachysine A is a promising candidate for developing novel chemotherapeutic agents as a methuosis inducer for cancer therapy.

Curcuma as an adjuvant in colorectal cancer treatment

Colorectal cancer (CRC) is the second leading cause of cancer death worldwide and mostly affects men. Around 20% of its incidence is by familiar disposition due to hereditary syndromes. The CRC treatment involves surgery and chemotherapy; however, the side effects of treatments and the fast emergence of drug resistance evidence the necessity to find more effective drugs. Curcumin is the main polyphenol pigment present in Curcuma longa, a plant widely used as healthy food with antioxidant properties. Curcumin has synergistic effects with antineoplastics such as 5-fluorouracil and oxaliplatin, as well anti-inflammatory drugs by inhibiting cyclooxygenase-2 and the Nuclear factor kappa B. Furthermore, curcumin shows anticancer properties by inhibition of the Wnt/β-catenin, Hedgehog, Notch, and the phosphatidylinositol-3-kinase (PI3K)/Akt and the mammalian target of rapamycin (mTOR) signaling pathways implicated in the progression of CRC. However, the consumption of pure curcumin is less suitable, as the absorption is poor, and the metabolism and excretion are high. Pharmacological formulations and essential oils of the plant improve the curcumin absorption, resulting in therapeutical dosages. Despite the evidence obtained in vitro and in vivo, clinical studies have not yet confirmed the therapeutic potential of curcumin against CRC. Here we reviewed the last scientific information that supports the consumption of curcumin as an adjuvant for CRC therapy.

The Anti-Cancer Effect of Four Curcumin Analogues on Human Glioma Cells

Purpose

Glioblastoma multiforme (GBM) is the primary aggressive malignancy of the brain with poor outcome. Curcumin analogues are polyphenolic compounds as the bioactive substances extracted from turmeric. This study aims to investigate the anti-cancer effects of four curcumin analogues. Furthermore, the molecular mechanisms of dimethoxycurcumin in human gliomas were analyzed by Western blot.

Materials and Methods

Human LN229 and GBM8401 glioma cells were treated by four curcumin analogues with different number of methoxy groups. The cell viability, cell cycle, apoptosis, proliferation and ROS production of human gliomas were analyzed by flow cytometry. Moreover, the effects of four curcumin analogues on tumorigenesis of gliomas were conducted by wound healing assay and colony formation assay. Furthermore, the molecular mechanisms of dimethoxycurcumin in human gliomas were analyzed by Western blot.

Results

Our data showed that four different curcumin analogues including curcumin, bisdemethoxycurcumin, demethoxycurcumin, and dimethoxycurcumin promote sub-G1 phase, G2/M arrest, apoptosis, and ROS production in human glioma cells. Moreover, dimethoxycurcumin suppressed cell viability, migration, and colony formation, induction of sub-G1, G2/M arrest, apoptosis, and ROS production in glioma cells. Moreover, the mechanism of dimethoxycurcumin is ROS production to increase LC3B-II expression to induce autophagy. Furthermore, dimethoxycurcumin suppressed apoptotic marker, BCL-2 to promote apoptosis in LN229 and GBM8401 glioma cells.

Conclusion

Our study found that dimethoxycurcumin induced apoptosis, autophagy, ROS production and suppressed cell viability in human gliomas. Dimethoxycurcumin might be a potential therapeutic candidate in human glioma cells.

Exploring Sonic Hedgehog Cell Signaling in Neurogenesis: Its Potential Role in Depressive Behavior

Depression is the most prevalent form of neuropsychiatric disorder affecting all age groups globally. As per the estimation of the World Health Organization (WHO), depression will develop into the foremost reason for disability globally by the year 2030. The primary neurobiological mechanism implicated in depression remains ambiguous; however, dysregulation of molecular and signaling transductions results in depressive disorders. Several theories have been developed to explain the pathogenesis of depression, however, none of them completely explained all aspects of depressive-pathogenesis. In the current review, we aimed to explore the role of the sonic hedgehog (Shh) signaling pathway in the development of the depressive disorder and its potential as the therapeutic target. Shh signaling has a crucial function in neurogenesis and neural tube patterning during the development of the central nervous system (CNS). Shh signaling performs a basic function in embryogenesis and hippocampal neurogenesis. Moreover, antidepressants are also known to enhance neurogenesis in the hippocampus, which further suggests the potential of Shh signaling. Furthermore, there is decreased expression of a glioma-associated oncogene (Gli1) and Smoothened (Smo) in depression. Moreover, antidepressants also regulate brain-derived neurotrophic factor (BDNF) and wingless protein (Wnt) signaling, therefore, Shh may be implicated in the pathogenesis of the depressive disorder. Deregulation of Shh signaling in CNS results in neurological disorders such as depression.

Effects of curcumin on neurological diseases: focus on astrocytes

Astrocytes are the most abundant glial cells in the central nervous system, and are important players in both brain injury and neurodegenerative disease. Curcumin (1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione), the major active component of turmeric, belongs to the curcuminoid family that was originally isolated from the plant Curcuma longa. Several studies suggest that curcumin may have a beneficial impact on the brain pathology and aging. These effects are due to curcumin's antioxidant, free-radical scavenging, and anti-inflammatory activity. In light of this, our current review aims to discuss the role of astrocytes as essential players in neurodegenerative diseases and suggest that curcumin is capable of direct inhibition of astrocyte activity with a particular focus on its effects in Alexander disease, Alzheimer's disease, ischemia stroke, spinal cord injury, Multiple sclerosis, and Parkinson's disease.

Complementary and integrative health interventions and their association with health-related quality of life in the primary brain tumor population

BACKGROUND AND PURPOSE

Little is known about complementary and integrative health intervention usage in the primary brain tumor population. We aimed to identify the percentage of patients using these practices and explore the impact on quality of life.

MATERIALS AND METHODS

Clinical records from patients seen in clinic between December 16, 2013 and February 28, 2014 were reviewed retrospectively. The questionnaires used were a modified version of the International Complementary and Alternative Medicine Questionnaire, the Functional Assessment of Cancer Therapy- Brain Cancer and the Functional Assessment of Chronic Illness Therapy- Fatigue.

RESULTS

76% of patients utilized a complementary and integrative health modality. The most frequently reported modalities used were vitamins, massage, and spiritual healing, prayer, diet and meditation.

CONCLUSION

These results confirm the usage of complementary and integrative health practices within the primary brain tumor population; however, there was no evidence of association between use and quality of life.

Paraptosis in human glioblastoma cell line induced by curcumin

Curcumin is a polyphenol compound extracted from Curcuma longa plant, is a molecule with pleiotropic effects that suppresses transformation, proliferation and metastasis of malignant tumors. Curcumin can cause different kinds of cell death depending of its concentration on the exposed cell type. Here we show that exposure of the glioblastoma cell line A172 to curcumin at 50 μM, the IC50, causes morphological change characteristic of paraptosis cell-death. Vesicles derived from the endoplasmic reticulum (ER) and low membrane potential of the mitochondria were constantly found in the exposed cells. Furthermore, changes in expression of the ER Stress Response (ERSR) genes IRE1 and ATF6, and the microRNAs (miRNAs) miR-27a, miR-222, miR-449 was observed after exposure to curcumin. AKT-Insulin and p53-BCL2 networks were predicted being modulated by the affected miRNAs. Furthermore, AKT protein levels reduction was confirmed. Our data, strongly suggest that curcumin exerts its cell-death properties by affecting the integrity of the reticulum, leading to paraptosis in the glioblastoma cells. These data unveils the versatility of curcumin to control cancer progression.

Curcumin inhibits activation induced by urban particulate material or titanium dioxide nanoparticles in primary human endothelial cells

Curcumin has protective effects against toxic agents and shows preventive properties for various diseases. Particulate material with an aerodynamic diameter of ≤10 μm (PM10) and titanium dioxide nanoparticles (TiO2-NPs) induce endothelial dysfunction and activation. We explored whether curcumin is able to attenuate different events related to endothelial activation. This includes adhesion, expression of adhesion molecules and oxidative stress induced by PM10 and TiO2-NPs. Human umbilical vein endothelial cells (HUVEC) were treated with 1, 10 and 100 μM curcumin for 1 h and then exposed to PM10 at 3 μg/cm2 or TiO2-NPs at 10 μg/cm2. Cell adhesion was evaluated by co-culture with U937 human myelomonocytic cells. Adhesion molecules expression was measured by flow cytometry after 3 or 24 h of exposure. Oxidative stress was determined by 2,7-dichlorodihydrofluorescein (H2DCF) oxidation. PM10 and TiO2-NPs induced the adhesion of U937 cells and the expression of E- and P-selectins, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and platelet-endothelial cell adhesion molecule-1 (PECAM-1). The expression of E- and P-selectins matched the adhesion of monocytes to HUVEC after 3 h. In HUVEC treated with 1 or 10 μM curcumin, the expression of adhesion molecules and monocytes adhesion was significantly diminished. Curcumin also partially reduced the H2DCF oxidation induced by PM10 and TiO2-NPs. Our results suggest an anti-inflammatory and antioxidant role by curcumin attenuating the activation caused on endothelial cells by exposure to particles. Therefore, curcumin could be useful in the treatment of diseases where an inflammatory process and endothelial activation are involved.

Evaluation of intracavitary administration of curcumin for the treatment of sarcomatoid mesothelioma

A rat model of sarcomatoid mesothelioma, mimicking some of the worst clinical conditions encountered, was established to evaluate the therapeutic potential of intracavitary curcumin administration.

The M5-T1 cell line, selected from a collection established from F344 rats induced with asbestos, produces tumors within three weeks, with extended metastasis in normal tissues, after intraperitoneal inoculation in syngeneic rats. The optimal concentration/time conditions for killing M5-T1 cells with curcumin were first determined in vitro. Secondly, the potential of intraperitoneal curcumin administration to kill tumor cells in vivo was evaluated in tumor-bearing rats, in comparison with a reference epigenetic drug, SAHA.

Both agents administered at days 21 and 26 after tumor challenge produced necrosis within the solid tumors at day 28. However, tumor tissue necrosis induced with curcumin was much more extensive than with SAHA, and was characterized by infiltration with mononuclear phagocytic cells. In contrast, tumor tissue treated with SAHA contained foci of resistant cells and was infiltrated by many isolated CD8+ cells. The treatment of tumor-bearing rats with 1.5 mg/kg curcumin on days 7, 9, 11 and 14 after tumor challenge dramatically reduced the mean total tumor mass at day 16. Clusters of CD8+ T lymphocytes were observed at the periphery of small residual tumor masses in the peritoneal cavity, which presented a significant reduction in mitotic index, IL6 and vimentin expression compared with tumors in untreated rats.

These data open up interesting new prospects for the therapy of sarcomatoid mesothelioma with curcumin and its derivatives.

Targeting sonic hedgehog signaling in neurological disorders

Sonic hedgehog (Shh) signaling influences neurogenesis and neural patterning during the development of central nervous system. Dysregulation of Shh signaling in brain leads to neurological disorders like autism spectrum disorder, depression, dementia, stroke, Parkinson's diseases, Huntington's disease, locomotor deficit, epilepsy, demyelinating disease, neuropathies as well as brain tumors. The synthesis, processing and transport of Shh ligand as well as the localization of its receptors and signal transduction in the central nervous system has been carefully reviewed. Further, we summarize the regulation of small molecule modulators of Shh pathway with potential in neurological disorders. In conclusion, further studies are warranted to demonstrate the potential of positive and negative regulators of the Shh pathway in neurological disorders.

Curcumin activates autophagy and attenuates oxidative damage in EA.hy926 cells via the Akt/mTOR pathway

Curcumin, which is the effective component of turmeric (Curcuma longa), has previously been shown to exert potent antioxidant, antitumor and anti‑inflammatory activities in vitro and in vivo. However, the mechanism underlying the protective effects of curcumin against oxidative damage in endothelial cells remains unclear. The present study aimed to examine the effects of curcumin on hydrogen peroxide (H2O2)‑induced apoptosis and autophagy in EA.hy926 cells, and to determine the underlying molecular mechanism. Cultured EA.hy926 cells were treated with curcumin (5‑20 µmol/l) 4 h prior to and for 4 h during exposure to H2O2 (200 µmol/l). Oxidative stress resulted in a significant increase in the rate of cell apoptosis, which was accompanied by an increase in the expression levels of caspase‑3 and B‑cell lymphoma 2 (Bcl‑2)‑associated X protein (Bax), and a decrease in the expression levels of Bcl‑2. Treatment with curcumin (5 or 20 µmol/l) significantly inhibited apoptosis, and reversed the alterations in caspase‑3, Bcl‑2 and Bax expression. Furthermore, curcumin induced autophagy and microtubule‑associated protein 1A/1B‑light chain 3‑Ⅱ expression, and suppressed the phosphorylation of Akt and mammalian target of rapamycin (mTOR). These results indicated that curcumin may protect cells against oxidative stress‑induced damage through inhibiting apoptosis and inducing autophagy via the Akt/mTOR pathway.