Curcumin Pretreatment Research Articles

Effects of Curcumin on High Glucose-Induced Epithelial-to-Mesenchymal Transition in Renal Tubular Epithelial Cells Through the TLR4-NF-κB Signaling Pathway.

ObjectiveDiabetic kidney disease (DKD) is a microvascular complication in diabetes mellitus, while tubuloepithelial to mesenchymal transition (EMT) of mature tubular epithelial cells is a key point in the early development and progression of renal interstitial fibrosis. The present study aimed to investigate the protective effects of Curcumin on EMT and fibrosis in cultured normal rat kidney tubular epithelial cell line (NRK-52E).MethodsBy using immunofluorescence staining and Western blot protocols, in vitro experiments were designed to analyze EMT markers, including collagen I and E-cadherin in high glucose (HG) exposed NRK-52E cells and to detect the expression levels of phosphorylated-NF-κB, TLR4 and reactive oxygen species (ROS) after Curcumin pre-treatment. With co-treatment with TAK242, these molecules in the TLR4-NF-κB signaling pathway were further evaluated.ResultsCurcumin decreased the HG-induced EMT levels and ROS production in NRK-52E cells. Furthermore, Curcumin was found to inhibit the TLR4-NF-κB signaling activation in HG-induced EMT of NRK-52E cells.ConclusionThe present study provides evidence suggesting a novel mechanism that Curcumin exerts the anti-fibrosis effects via inhibiting activation of the TLR4-NF-κB signal pathway and consequently protecting the HG-induced EMT in renal tubular epithelial cells. Thereby, TLR4-NF-κB may be a useful target for therapeutic intervention in DKD.

Curcumin ameliorates IL‐1β‐induced apoptosis by activating autophagy and inhibiting the NF‐κB signaling pathway in rat primary articular chondrocytes

Articular cartilage damage and chondrocyte apoptosis are common features of rheumatoid arthritis and osteoarthritis. Recently, curcumin has been reported to exhibit protective effects on degeneration in articular cartilage diseases. However, the effects and mechanisms of curcumin on articular chondrocyte injury remain to be elucidated. The aim of the present study is to investigate the chondroprotective mechanisms of curcumin on interleukin-1β (IL-1β)-induced chondrocyte apoptosis in vitro. The results revealed that IL-1β decreased cell viability and induced apoptosis in primary articular chondrocytes. Curcumin pretreatment reduced IL-1β-induced articular chondrocyte apoptosis. In addition, treatment with curcumin increased autophagy in articular chondrocytes and protected against IL-1β-induced apoptosis. The curcumin-mediated protection against IL-1β induced apoptosis was abolished when cells were treated with the autophagy inhibitor 3-methyladenine or transfected with Beclin-1 small interfering RNA. Furthermore, IL-1β stimulation significantly increased the phosphorylation levels of nuclear factor (NF)-κB p65 and glycogen synthase kinase-3β, and decreased the phosphorylation levels of β-catenin in articular chondrocytes, and these alterations to the phosphorylation levels were partly reversed by treatment with curcumin. Dual-luciferase and electrophoretic mobility shift assays demonstrated that IL-1β increased NF-κB p65 promoter activity in chondrocytes, and this was also reversed by curcumin. Pretreatment with the NF-κB inhibitor pyrrolidine dithiocarbamate enhanced the protective effects of curcumin on chondrocyte apoptosis, but Wnt/β-catenin inhibitor, XAV-939, did not exhibit this effect. Molecular docking and dynamic simulation studies results showed that curcumin could bound to RelA (p65) protein. These results indicate that curcumin may suppress IL-1β-induced chondrocyte apoptosis through activating autophagy and restraining NF-κB signaling pathway.

Mitigation of Gliadin-Induced Inflammation and Cellular Damage by Curcumin in Human Intestinal Cell Lines.

Wheat is a major diet from many years; apart from its nutritious value, the wheat protein gliadin is responsible for many inflammatory diseases like celiac disease (CD), and non-celiac gluten sensitivity (NCGS). In this study, the gliadin-induced inflammation and associated cellular damage along with the protective role of curcumin was evaluated using human intestinal cell lines (HCT-116 and HT-29) as a model. Cells were cultured and exposed to 160 μg/ml of gliadin, 100 μM H2O2, and 10 μM curcumin (3 h pretreatment) followed by the assessment of inflammation. Spectrophotometric methods, real-time-PCR, ELISA, Western blotting, and confocal microscopy techniques were used to assess inflammatory markers such as advanced oxidation protein products (AOPPs) level, activity of myeloperoxidase (MPO) and NADPH oxidase (NOX), cytokines, and cell damage markers. The results show that gliadin increases the AOPPs level and the activity of MPO and NOX expression. It enhances inflammation by increasing expression of pro-inflammatory cytokines, altered expression of anti-inflammatory, and regulatory cytokines. It exacerbates the cellular damage by increasing MMP-2 and 9 and decreasing integrin α and β expression. Gliadin promotes disease pathogenesis by inducing the inflammation and cellular damage which further alter the cellular homeostasis. The pretreatment of curcumin counteracts the adverse effect of gliadin and protect the cells via diminishing the inflammation and help the cell to regain the cellular morphology suggesting phytochemical-based remedial interventions against wheat allergies.

Curcumin Alleviates Ketamine-Induced Oxidative Stress and Apoptosis via Nrf2 Signaling Pathway in Rats’ Cerebral Cortex and Hippocampus

Aims: To study the protective effect of curcumin on nerve damage caused by ketamine anesthesia by Nrf2 signaling pathway. Methods: Rat cerebral cortex and hippocampus were collected for Nissl staining and immunohistochemistry to detect the number of neurons and the expressions of Caspase3, Bcl-2 and Bax. The optimal concentration of ketamine, curcumin and H2O2 on PC12 cells was determined by CCK-8 assay. Flow cytometry was used to detect the changes of reactive oxygen species and apoptosis rate in each group. Immunofluorescence was performed to observe whether Nrf2 entered the nucleus. Both tissues and cells were simultaneously subjected to RT-PCR and Western blotting detection. Oxidative stress levels were measured using a malondialdehyde (MDA) and superoxide dismutase (SOD) assay kit. Findings: Ketamine decreased the number of neurons in rats cortex and hippocampus. The expression of Bax and Caspase3 protein were up-regulated and the Bcl-2 was down-regulated in cortex and hippocampus. The cell viability of PC12 cells decreased. The content of MDA increased and the activity of SOD decreased in cortex, hippocampus and PC12 cells. Ketamine affected the expressions of some genes in Nrf2 signal pathway. Curcumin pretreatment could prevent the damage caused by ketamine. Conclusion: Curcumin could activate Nrf2 signaling pathway to alleviate oxidative stress and apoptosis, thus reducing ketamine-induced damage to cerebral cortex, hippocampus and PC12 cells during development. Our study provides a potential scheme for the safe use of anesthetics in clinic. Funding Information: This study was supported by the National Natural Science Foundation of China (31572580 and 31372491). Declaration of Interests: The authors declare that there are no conflicts of interest. Ethics Approval Statement: All experiments were carried out in accordance with the relevant laws of China and the animal welfare guidelines and experimental procedures of China. All procedures used in this study were approved by the animal protection and Utilization Committee of Northeast Agricultural University (SRM-11).

Attenuation of Docetaxel-induced Oxidative Stress and Apoptosis in HEK 293 Human Embryonic Kidney Cells by Curcumin Treatment

Docetaxel (DOC) is a chemotherapeutic that induces microtubule stabilization. It is often used in breast, prostate, lung and gastric cancers but severe side effects such as cardiotoxicity, neurotoxicity, hepatotoxicity, and nephrotoxicity limit its usage. Curcumin (CUR), a natural bioactive compound derived from turmeric. Here, the possible preventive effect of CUR against DOC-induced oxidative stress and apoptosis on HEK-293 immortalized human embryonic kidney cells. Viability was assessed via MTT assay. The generation of ROS was measured by CM-H2DCFDA dye. Phosphatidylserine externalization and caspase 3/7 activity were used to measure apoptosis. CUR pretreatment remarkably inhibited DOC-induced cell viability reduction, ROS generation, and cell apoptosis in HEK-293 cells. Moreover, this study revealed that CUR pretreatment decreased the caspase-3 activity. Thus, this study highlights the novel pharmacological mechanisms of CUR and understanding the detailed mechanisms of CUR action could lead to novel renoprotective interventions.

Biochemical study on the protective effect of curcumin on acetaminophen and gamma-irradiation induced hepatic toxicity in rats.

Acetaminophen (APAP) is one of the few recommended analgesic and antipyretic drugs in some critical cases such as viral disease COVID-19. However, the unrestricted use of APAP develops liver disorders. Hepatotoxicity and liver injury can also be induced by ionizing radiation (IR) during radiotherapy. The data of the current study represents that treatment of rats with either APAP-overdose, or gamma-irradiation (R) induces hepatotoxicity, results in significant increases of the hepatic-enzymes activities (ALT, AST, ALP, GGT, LDH, and MDH), as well as enhancement of triglycerides, total cholesterol levels, combined with declines in albumin and total protein contents. An enhancement of the lipid peroxides (malondialdehyde; MDA), and nitric oxide levels along with a decline of reduced glutathione contents and suppression of superoxide dismutase, catalase, and glutathione peroxidase activities are also observed within the liver tissues of intoxicated animals. TNF-α, IL-1β, IL-6, iNOS, Cytochrome P450 2E1 (CYP2E1), miR-802 gene expression, NF-κB, and calcium levels are up-regulated, while Nuclear factor erythroid-related factor-2 (Nrf2), Hemoxygenase-1 (HO-1) protein and gene expressions, as well as, glutamate-cysteine ligase catalytic subunit (GCLC), NAD(P)H-Quinone oxidoreductase (NQO1), and miR-122 gene expressions are down-regulated in the livers of intoxicated animals. All these parameters show significant improvement in R/APAP intoxicated animals. Curcumin pretreatment develops an amelioration of these effects in APAP-overdose, R-exposure, or R/APAP treatments. In conclusion, oral administration of curcumin shows hepatoprotective effects against APAP-overdose induced hepatic damage in normal and gamma-irradiated rats through prospective regulation of the therapeutic targets CYP2E1, Nrf2, and NF-κB, via organizing the miR-122 and miR-802 gene expression.

Curcumin inhibits APOE4-induced injury by activating peroxisome proliferator-activated receptor-γ (PPARγ) in SH-SY5Y cells.

Objective(s):The human apolipoprotein E4 (APOE4) is associated with various brain injuries and neurodegenerative changes. Curcumin is an active ingredient isolated from the root of turmeric and is believed to have therapeutic effects on neurodegenerative diseases. The aim of this study was to investigate the effects of curcumin on APOE4-induced neurological damage and explore its molecular mechanisms.Materials and Methods:SH-SY5Y cells were pretreated with curcumin for 24 hr and transfected with human APOE4 gene using Lipofectamine 2000. Then, the effect of curcumin on the transfected cells was detected by ELISA, immunofluorescence staining and Western blot.Results:The production or expression of proinflammatory cytokines and proteins, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), nitric oxide (NO), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was significantly increased in SH-SY5Y cells transfected with APOE4, and curcumin inhibited APOE4-induced cellular inflammatory damage. Western blot analysis showed that, after transfection with APOE4, the expression of total nuclear factor kappa B (NF-κB) p65 and p-NF-κB p65 in the nucleus was increased, and curcumin inhibited the nuclear translocation of p65. The overexpression of APOE4 inhibited the expression of peroxisome proliferator-activated receptor-γ (PPARγ), whereas curcumin reversed and increased the expression of PPARγ protein. Down-regulating PPAR-γ with the inhibitor GW9662 and the shPPARγ gene confirmed that the NF-κB signaling pathway was inhibited by PPARγ. Conclusion:This study suggests that APOE4 overexpression can induce cellular inflammatory damage, and pretreatment of curcumin could exert an anti-inflammatory effect by upregulating the expression of PPARγ to inhibit the activation of NF-κB signaling pathway.

Curcumin alleviates acute kidney injury in a dry-heat environment by reducing oxidative stress and inflammation in a rat model.

Curcumin exhibits anti‐inflammatory and antioxidant activities. We investigated the protective effects of curcumin in a renal injury rat model under dry‐heat conditions. We divided Sprague‐Dawley rats into four groups: dry‐heat 0‐ (normal temperature control group), 50‐, 100‐, and 150‐minute groups. Each group was divided into five subgroups (n = 10): normal saline (NS), sodium carboxymethylcellulose (CMCNa), and curcumin pretreated low, medium, and high‐dose (50, 100, and 200 mg/kg, respectively) groups. Compared to the normal temperature group, serum creatinine, blood urea nitrogen, urinary kidney injury molecule‐1, and neutrophil gelatinase‐associated load changes in lipoprotein (NGAL) levels were significantly increased in the dry‐heat environment group (P < .05); inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2) expression and malondialdehyde (MDA) and related inflammatory factor levels were increased in the kidney tissue. Superoxide dismutase (SOD) and catalase (CAT) levels were decreased. However, following all curcumin pretreatment, the serum levels of kidney injury indicators and NGAL were decreased in the urine compared to those in the NS and CMCNa groups (P < .05), whereas renal SOD and CAT activities were increased and MDA was decreased (P < .05). Renal tissues of the 150‐minute group showed obvious pathological changes. Compared to the NS group, pathological changes in the renal tissues of the 100‐ and 200‐mg/kg curcumin groups were significantly reduced. Furthermore, iNOS and COX‐2 expression and inflammatory factor levels were decreased after curcumin treatment. Curcumin exerted renoprotective effects that were likely mediated by its antioxidant and anti‐inflammatory effects in a dry‐heat environment rat model.

Molecular mechanism of olaquindox-induced hepatotoxicity and the hepatic protective role of curcumin

Olaquindox (OLA) is a chemosynthetic growth promoter, which could promote the treatment of bacterial infections and improve feed energy efficiency. Hepatotoxicity is still a poor feature associated with the adverse effects of OLA. The present study aimed to investigate the molecular mechanism of OLA-induced hepatotoxicity and the protective role of curcumin in mice and HepG2 cells. The result showed that representative biomarkers involved in mitochondrial pathway, p53 pathway, mitogen-activated protein kinase (MAPK) pathway, autophagy and antioxidant pathway were activated. Furthermore, curcumin attenuated OLA-induced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and liver damage in mice. In addition, cell viability of HepG2 was enhanced by curcumin pretreatment at 5, 10 and 20 μM. Meanwhile, curcumin markedly ameliorated OLA-induced oxidative stress, apoptosis and mitochondrial dysfunction. Moreover, curcumin pretreatment significantly up-regulated the expressions of nuclear factor erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1(HO-1) and down-regulated the expressions of nuclear factor-kappaB (NF-kB) and p53 through reduced the nuclear translocation of NF-kB induced by OLA. In summary, our findings indicated that OLA-induced hepatotoxicity involved in mitochondrial apoptosis, autophagy, p53 pathway, Nrf2/HO-1 pathways, and curcumin regulated OLA-induced liver damage, oxidative stress and apoptosis via activation of Nrf2/HO-1 pathway and suppression of p53 and NF-kB pathway.

Curcumin targets vascular endothelial growth factor via activating the PI3K/Akt signaling pathway and improves brain hypoxic-ischemic injury in neonatal rats.

This study aimed to evaluate the effect of curcumin on brain hypoxic-ischemic (HI) damage in neonatal rats and whether the phosphoinositide 3-kinase (PI3K)/Akt/vascular endothelial growth factor (VEGF) signaling pathway is involved. Brain HI damage models were established in neonatal rats, which received the following treatments: curcumin by intraperitoneal injection before injury, insulin-like growth factor 1 (IGF-1) by subcutaneous injection after injury, and VEGF by intracerebroventricular injection after injury. This was followed by neurological evaluation, hemodynamic measurements, histopathological assessment, TUNEL assay, flow cytometry, and western blotting to assess the expression of p-PI3K, PI3K, p-Akt, Akt, and VEGF. Compared with rats that underwent sham operation, rats with brain HI damage showed remarkably increased neurological deficits, reduced right blood flow volume, elevated blood viscosity and haematocrit, and aggravated cell damage and apoptosis; these injuries were significantly improved by curcumin pretreatment. Meanwhile, brain HI damage induced the overexpression of p-PI3K, p-Akt, and VEGF, while curcumin pretreatment inhibited the expression of these proteins. In addition, IGF-1 treatment rescued the curcumin-induced down-regulated expression of p-PI3K, p-Akt, and VEGF, and VEGF overexpression counteracted the inhibitory effect of curcumin on brain HI damage. Overall, pretreatment with curcumin protected against brain HI damage by targeting VEGF via the PI3K/Akt signaling pathway in neonatal rats.

Effects of curcumin, D-pinitol alone or in combination in cytotoxicity induced by arsenic in PC12 cells

Arsenic is a well-known potent toxicant affecting people by causing various human diseases. Long-term exposure to arsenic has strong adverse health effects on liver and kidney disorders, and various forms of cancer. Contrarily, curcumin and D-pinitol are bioactive dietary compounds that have antioxidant properties. Both are used to treat a broad variety of human diseases. Thus, we hypothesized that both may have synergistic effects against arsenic-induced toxicity in PC12 cells. Cells were pretreated with curcumin (1, 2.5, 5 and 10 μM), D-pinitol (1, 2.5, 5 and 10 μM) alone or in combination, then exposed to sodium arsenite (10 μM). The final concentration of curcumin 2.5 μM and D-pinitol 5 μM was selected for combination treatment based on their highest protection at lowest concentration against arsenic toxicity. Results demonstrated that pretreatment of curcumin and D-pinitol and their combined treatment with arsenic rescued PC12 cells. Western blot analysis results showed that pretreatment of curcumin and D-pinitol and their combined treatment with arsenic significantly inhibited arsenic-induced cell death through up-regulation of pro-survival proteins and down-regulation of cell death-related proteins, although these protein expressions were negatively regulated by arsenic. Furthermore, the effect of combined treatment with curcumin and D-pinitol was stronger than individual treatment.

Curcumin attenuates inflammation and cell apoptosis through regulating NF-κB and JAK2/STAT3 signaling pathway against acute kidney injury

ABSTRACT Curcumin alleviates septic acute kidney injury (SAKI); however, the underlying mechanism remained unclear. To explore this, SAKI cell model and mice model were conducted by using LPS and cecal ligation and puncture (CLP), respectively. Cell counting kit-8 (CCK-8) and enzyme-linked immunosorbent assay (ELISA) assays indicated that LPS reduced the viability, but upregulated the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6, whereas Curcumin pretreatment had no effect on viability, but reduced the levels of TNF-α and IL-6. Further assays showed that Curcumin partly attenuated the LPS-induced injury as the viability was enhanced, TNF-α and IL-6 expressions and cell apoptosis rates were reduced. Western blot analysis indicated that Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3, p-65-NF-κB and cell apoptosis pathways were activated by LPS but suppressed by Curcumin. Mice SAKI model further indicated that the serum Cystatin C (Cys-C), creatinine (Cr) and blood urea nitrogen (BUN) were increased within 24 h of model construction while those indicators were decreased at 48 h. Pretreated with Curcumin, NF-κB inhibitor (PDTC) or JAK2 inhibitor (AG-490) could weaken the renal histological injury and the increased serum Cys-C, Cr and BUN, IL-6 and TNF-α induced by CLP. Moreover, PDTC, AG-490 and Curcumin all significantly reversed the previously increased expressions of p-JAK2/STAT3, p-p65 and proapoptotic proteins in the mice with AKI. The present study revealed that Curcumin attenuated SAKI through inhibiting NF-κB and JAK2/STAT3 signaling pathways, and proposed that Curcumin could be a potential therapeutic agent for treating SAKI.

Curcumin Promotes the Expression of IL-35 by Regulating Regulatory T Cell Differentiation and Restrains Uncontrolled Inflammation and Lung Injury in Mice.

Interleukin (IL)-35, which has an anti-inflammatory role in acute respiratory distress syndrome (ARDS)/acute lung injury (ALI), is relatively promising as a drug target. Studies have shown that curcumin may play a therapeutic role in ALI and enhance the suppressive function of regulatory T cells (Tregs). To illustrate the effect of curcumin on the regulation of Treg cell differentiation and expression of IL-35, we built a cecal ligation and puncture (CLP)-induced acute lung injury mouse mode with curcumin pretreatment. The expression of IL-35 in serum, severity of lung injury, IL-17A in lung tissue, survival rate, Treg-related cytokines levels in serum, nuclear factor-kappa B (NF-κB)'s nuclear translocation in lung tissue, and splenic CD4+CD25+FOXP3+ Tregs were assessed. Furthermore, the proportion of Tregs, STAT5, and IL-35 expression during naïve CD4+ T cell differentiation in vitro was measured. Compared with the CLP group, the increased IL-35 expression in CLP with the curcumin pretreatment (CLP + Cur) group was consistent with the decreased severity of lung injury, IL-17A protein levels in lung tissue, and Treg-related cytokines levels. Pretreatment with curcumin, the survival rate climbed to 50%, while the mortality rate was 100% in the CLP group. In addition, splenic CD4+CD25+FOXP3+ Treg cells increased in the CLP + Cur group. In vitro, CD4+CD25+FOXP3+ Treg cells from naïve CD4+ T cells, STAT5 proportion, and IL-35 expression increased after curcumin treatment. These findings showed that curcumin might regulate IL-35 by activating the differentiation of Treg cells to control the inflammation in acute lung injury.

Curcumin alleviates arsenic-induced toxicity in PC12cells via modulating autophagy/apoptosis.

Arsenic is a recognized highly toxic contaminant, responsible for numerous human diseases and affecting many millions of people in different parts of the world. Contrarily, curcumin is a natural dietary polyphenolic compound and the main active ingredient in turmeric. Recently it has drawn great attention due to its diverse biological activities, strong antioxidant properties and therapeutic potential against many human ailments. In this study, we aimed to explore the protective effects and the regulatory role of curcumin on arsenic-induced toxicity and gain insights into biomolecular mechanism/s. Arsenic (10μM) treatment in PC12cells for 24h induced cytotoxicity by decreasing cell viability and intracellular glutathione level and increasing lactate dehydrogenase activity and DNA fragmentation. In addition, arsenic caused apoptotic cell death in PC12cells, which were confirmed from flow cytometry results. Moreover, arsenic (10μM) treatment significantly down-regulated the inhibition factors of autophagy/apoptosis; mTOR, Akt, Nrf2, ERK1, Bcl-x, Xiap protein expressions, up-regulated the enhanced factors of autophagy/apoptosis; ULK, LC3, p53, Bax, cytochrome c, caspase 9, cleaved caspase 3 proteins and eventually caused autophagic and apoptotic cell death. However, curcumin (2.5μM) pretreatment with arsenic (10μM) effectively saves PC12cells against arsenic-induced cytotoxicity through increasing cell viability, intracellular GSH level and boosting the antioxidant defense system, and limiting the LDH activity and DNA damage. Furthermore, pretreatment of curcumin with arsenic expressively alleviated arsenic-induced toxicity and cell death by reversing the expressions of proteins; mTOR, Akt, Nrf2, ERK1, Bcl-x, Xiap, ULK, LC3, p53, Bax, cytochrome c, caspase 9 and cleaved caspase 3. Our findings indicated that curcumin showed antioxidant properties through the Nrf2 antioxidant signaling pathway and alleviates arsenic-triggered toxicity in PC12cells by regulating autophagy/apoptosis.

Integrative transcriptome analysis and discovery of signaling pathways involved in the protective effects of curcumin against oxidative stress in tilapia hepatocytes

Summer outbreaks of the hepatobiliary syndrome in fish impose a heavy burden on aquaculture in China. Curcumin is a polyphenol with antioxidant activity that has been used to protect the health of fish livers, but the mechanism underlying its protective effect is unclear. In this study, an in vitro model of hepatocyte oxidative damage in Oreochromis niloticus was established using H2O2. Treatment with 5 mM H2O2 for 2.5 h markedly reduced cell viability and antioxidant activity and elevated lactate dehydrogenase (LDH) activity, indicating conditions that can be used to establish an oxidative stress model. Under H2O2 stress, curcumin pretreatment significantly maintained cell viability, reduced malondialdehyde (MDA) levels, and increased superoxide dismutase (SOD) activity. RNA-seq results showed that acute H2O2 treatment resulted in minor changes in gene expression, whereas curcumin changed the expression profile and affected cytochrome P450 (Cyp 450), glutathione (GSH) metabolism, and the peroxisome proliferator-activated receptor (PPAR) signaling pathway. Several critical antioxidant defense signaling pathways were identified, and altered expression was confirmed by q-PCR. These results indicate that curcumin might upregulate PPAR expression by increasing Cyp2J2 expression. Further experiments showed that curcumin can upregulate the Nrf2-Keap1 signaling pathway at the transcriptional level, and this upregulation can induce downstream defense genes, including glutamate cysteine ligase catalytic subunit(GCLC) and glutamate cysteine ligase modifier subunit (GCLM), and thereby promote GSH synthesis and the expression of related antioxidases. This study might shed light on the effects of curcumin on the prevention and alleviation of liver diseases in fish.

SUN-LB27 Interleukin-8 - a Possible Target for Melanoma Treatment? In-Vitro Studies Based on Human Melanoma Cell Models

Previous clinical studies showed that menstruating females were better protected in melanoma than post-menopausal women and men of any age. In addition, epidemiological studies showed an increased male mortality in melanoma. But these studies did not correlate with steroid status in females. Our in-vitro study showed female sex hormone progesterone significantly inhibited human melanoma cell growth. Further in-vitro study showed that progesterone action was mediated by a specific suppression of pro-inflammatory cytokine IL-8. Our research also showed that addition of IL-8 (1 ng/ml) to melanoma cells stimulated cell growth (117%) and suppression of IL-8 by curcumin (100 μM) pre-treatment suppressed human melanoma cell growth (26%) in-vitro. This observation prompted us to check the effect of male sex hormones androstenedione (AD) and testosterone (T) on melanoma cell growth. AD and T also suppressed cell growth and IL-8 secretion, but not as significantly as that of progesterone. However, addition of progesterone (10 μM) along with androgens showed an additive effect on the inhibition of melanoma cell growth and suppression of IL-8 secretion. As steroids (P, AD, T) targeted IL-8 for their action, it was decided to check whether vitamin-D3 also targeted IL-8 secretion and cell growth. Active form of vit-D3 (25 μM) also suppressed IL-8 secretion and cell growth. But, addition of progesterone (50 μM) along with D3 significantly suppressed cell growth and IL-8 secretion. This brought IL-8 into focus as a key molecule regulating melanoma cell growth. In order to check whether IL-8 was the molecule involved in regulating melanoma cell growth, IL-8 rescue experiment after curcumin (25 μM) pre-treatment was carried out. IL-8 (100 ng/ml) was able to rescue cell growth completely after pre-treatment with curcumin, suggesting IL-8 was the molecule involved in regulating melanoma cell growth. Literature also suggested important role for IL-8 in regulating melanoma cell growth. Conditional expression of IL-8 in nude mouse by Dr. Singh et al., indicated in-vivo role of IL-8 in melanoma growth and metastasis. Conclusion: Both, in-vitro and in-vivo studies suggested an important role for IL-8 in regulating melanoma growth and metastasis. So, IL-8 could be targeted to arrest melanoma growth and metastasis in-vivo. Hence, IL-8 could be a potential target for melanoma treatment.

Curcumin Attenuates Hemorrhagic Shock and Blood Replenish Resuscitation-induced Impairment of Pulmonary Barrier Function by Increasing SIRT1 and Reducing Malondialdehyde and TNF-α Contents and Neutrophil Infiltration in Lung in a Dose-Dependent Fashion

ObjectivesAcute lung injury (ALI) is a critical complication subsequent to hemorrhage shock and resuscitation (HSR) that frequently leads to multiple organ failure. Collective evidence suggested that the activation of pulmonary nicotinamide adenine dinucleotide-dependent deacetylase sirtuin-1 (SIRT1) plays a critical role in inhibiting the production of reactive oxygen species (ROS) and tumor necrosis factor (TNF)-α, as well as the protection against ALI. Curcumin is a potent activator of SIRT1 and possesses antioxidative and anti-inflammatory effects. In this study, we aim to investigate the dose-dependent protective effectiveness of curcumin pretreatment against HSR-induced ALI. MethodsStudies were conducted on Sprague-Dawley male rats in 5 groups: sham-operated, HSR, and HSR pretreated with 50, 200, or 400 mg/kg of curcumin. Curcumin was treated orally for 4 days and 1 hour before HSR induction. HSR was induced by decreasing the mean aortic pressure (MAP) to 40 mm Hg for 60 min through drawing blood from the left femoral artery, followed by blood replenish and leaving for another 120 min. At the end of HSR, the severity of ALI was assessed by pulmonary barrier function, via pulmonary filtration coefficient (Kfc) evaluated using isolated a perfused lung model, lung weight-to-body weight ratio (LW/BW), lung wet-to-dry weight ratio (W/D), and lavage protein concentration (PCBAL). We also examined the level of lung inflammation by lavage TNF-α and differential neutrophil count, and oxidative stress by lavage malondialdehyde (MDA). ResultsHSR significantly increased Kfc, LW/BW, W/D, and PCBAL; decreased pulmonary SIRT1; and increased lavage TNF-α and MDA contents and differential neutrophil count (P < .05). Curcumin pretreatment demonstrated lung protection efficacy with improved pulmonary barrier function, increased lung SIRT1, and reduced pulmonary oxidative stress and lung inflammation in a dose-dependent fashion. ConclusionsCurcumin pretreatment protects against HSR-induced pulmonary function impairment by increasing tissue SIRT1, which reduced lavage MDA and TNF-α and differential neutrophil count in a dose-dependent fashion.

Can Interleukin‐8 Alone be Responsible for Regulating Melanoma Growth &amp; Metastasis? In‐vitro studies based on treatments of human melanoma cell lines (BLM and 1205Lu) with sex steroids, IL‐8, curcumin and active vitamin‐D3

Previous clinical studies indicated that menstruating females were better protected in melanoma than post‐menopausal women and men of any age. But, the mechanism responsible for protection in menstruating females was not investigated. In addition, epidemiological data showed an increased male mortality in melanoma. Our in‐vitro study showed female sex hormone progesterone significantly inhibited human melanoma cell growth. Elisarray showed that progesterone action was mediated by a specific suppression of pro‐inflammatory cytokine IL‐8. So, the effect of male sex hormones androstenedione (AD) and testosterone (T) on melanoma cell growth was checked. AD and T also suppressed cell growth and IL‐8 secretion. But, addition of progesterone (10μM) along with androgens showed an additive effect on the inhibition of melanoma cell growth and IL‐8 suppression. This observation gave the idea of protective function of progesterone in melanoma, which was experimentally observed by a significant decrease in in‐vitro migration and adhesion functions. As steroids (P, AD, T) targeted IL‐8 for their actions, effect of vit‐D3 on melanoma cells was checked. Active form of vitamin‐D3 (25 μM) also targeted IL‐8 and decreased cell growth, suggesting IL‐8 could be regulating melanoma cell growth. In order to check whether IL‐8 regulated melanoma cell growth, IL‐8 was directly added to melanoma cells and endogenous IL‐8 was suppressed by 2 hrs pre‐treatment with curcumin. Addition of IL‐8 (1 ng/ml) to 1205Lu melanoma cells stimulated cell growth to 117%, whereas suppression of IL‐8 by curcumin (100 μM) pre‐treatment decreased cell growth to 24%. Similar results were obtained with BLM cells. This brought IL‐8 into focus as an important molecule regulating melanoma cell growth. Further in‐vitro experiments to restore curcumin (25 μM) pre‐treated melanoma cell growth (71.5%) by the addition of IL‐8 (100 ng/ml) resulted in a near complete restoration of cell growth (95.3%) in 1205Lu melanoma cells, suggesting IL‐8 could be the molecule regulating melanoma cell growth. Similar results were observed with BLM cells. In addition, in‐vivo conditional expression of IL‐8 in nude mouse by Dr. Singh et al., indicated involvement of IL‐8 in melanoma growth and metastasis.ConclusionBoth in‐vitro and in‐vivo studies indicated that IL‐8 alone could be responsible for regulating melanoma growth and metastasis. Hence, IL‐8 could be targeted to arrest melanoma growth and metastasis in‐vivo.

Curcumin augments therapeutic efficacy of TRAIL-based immunotoxins in leukemia.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) has been perceived as a promising anti-cancer agent because of its unique ability to kill cancer cells while sparing normal cells. However, translation of TRAIL to clinical studies was less successful as a large number of cancer cells acquire resistance to TRAIL-based monotherapies. An ideal strategy to overcome TRAIL resistance is to combine it with potential sensitizing agents. To investigate the TRAIL-sensitizing effect of curcumin in leukemia. The mechanism underlying TRAIL sensitization by curcumin was studied by flow cytometric analysis of TRAIL receptors in leukemic cell lines and patient samples, and immunoblot detection of TRAIL-apoptosis signaling proteins. Curcumin augments TRAIL-apoptotic signaling in leukemic cells by upregulating the expression of DR4 and DR5 along with suppression of cFLIP and anti-apoptotic proteins Mcl-1, Bcl-xl, and XIAP. Curcumin pre-treatment significantly (p < 0.01) enhanced the sensitivity of leukemic cell lines to TRAIL recombinant proteins. IL2-TRAIL peptide in the presence of curcumin induced potent apoptosis (p <0.001) as compared to TRAIL and IL2-TRAIL protein in leukemic cell lines with IC50 < 0.1 μΜ. Additionally, the combination of IL2-TRAIL peptide and curcumin showed significant cytotoxicity in patient peripheral blood mononuclear cells (PBMCs) with an efficacy of 90% in acute myeloid leukemia (AML), but 100% in acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL) and chronic myelomonocytic leukemia (CMML). Overall, our results suggest that curcumin potentiates TRAIL-induced apoptosis through modulation of death receptors and anti-apoptotic proteins which significantly enhances the therapeutic efficacy.

Curcumin Protects Human Trophoblast HTR8/SVneo Cells from H2O2-Induced Oxidative Stress by Activating Nrf2 Signaling Pathway.

Pregnancy complications are associated with oxidative stress induced by accumulation of trophoblastic ROS in the placenta. We employed the human trophoblast HTR8/SVneo cell line to determine the effect of curcumin pre-treatment on H2O2-induced oxidative damage in HTR8/Sveo cells. Cells were pretreated with 2.5 or 5 μM curcumin for 24 h, and then incubated with 400 μM H2O2 for another 24 h. The results showed that H2O2 decreased the cell viability and induced excessive accumulation of reactive oxygen species (ROS) in HTR8/Sveo cells. Curcumin pre-treatment effectively protected HTR8/SVneo cells against oxidative stress-induced apoptosis via increasing Bcl-2/Bax ratio and decreasing the protein expression level of cleaved-caspase 3. Moreover, curcumin pre-treatment alleviated the excessive oxidative stress by enhancing the activity of antioxidative enzymes. The antioxidant effect of curcumin was achieved by activating Nrf2 and its downstream antioxidant proteins. In addition, knockdown of Nrf2 by Nrf2-siRNA transfection abolished the protective effects of curcumin on HTR8/SVneo cells against oxidative damage. Taken together, our results show that curcumin could protect HTR8/SVneo cells from H2O2-induced oxidative stress by activating Nrf2 signaling pathway.