Sinomenine mitigates cisplatin-induced kidney injury by targeting multiple signaling pathways.

Sinomenine is a pharmacologically active alkaloid with antioxidant and anti-inflammatory properties. We aimed to investigate the mechanism of renoprotective activity of sinomenine in kidney injury induced by cisplatin (CP). Sinomenine (5 mg/kg) was administered to mice orally in two doses, the second day after intraperitoneal application of CP (13 mg/kg). Sinomenine ameliorated kidney injury and decreased serum levels of urea and creatinine and renal expression of NGAL and KIM-1. The increase in HO-1, 4-HNE, 3-NT and TNF-α renal expression was mitigated by sinomenine. Additionally, sinomenine reduced the expression of p21, Bax, Noxa, caspase-3 and -8 and PARP1 cleavage in mice kidneys as well as the number of TUNEL-positive cells. Sinomenine attenuated CP-induced activation of ERK1/2, Akt, FOXO3a, STAT3 and NF-κB and restored Sirtuin 6 expression. In the human proximal tubular cell line HK2, sinomenine 100 µM reduced the toxic effect of CP 30 µM. Our current findings suggest that sinomenine suppresses CP-induced oxidative stress, inflammation and apoptosis in mice kidneys by targeting multiple signaling pathways.

Oleanolic acid induces HCT116 colon cancer cell death through the p38/FOXO3a/Sirt6 pathway.

Oleanolic acid (OA) is a natural compound that possesses numerous beneficial health effects, including anticancer activity. The current study aimed to investigate the role of forkhead box O3a (FOXO3a) in autophagy/mitophagy by OA in HCT116 cell line. OA dose-dependently reduced viability of HCT116 cells, with IC50 = 29.8 µΜ. The expression of cleaved caspase-3 and poly (ADP-ribose) polymerase 1 increased after OA treatment, suggesting induction of apoptosis. Concurrently, OA induced autophagy, evidenced by increased expression of Beclin-1, autophagy-related protein 5 and microtubule-associated protein1A/1B-light chain 3 beta (LC3B), which played a prosurvival role. The induction of mitophagy was suggested by increased expression of p62 and PTEN-induced kinase 1 and reduced expression of translocase of outer mitochondrial membrane 20, which colocalized with LC3B. OA also induced nuclear accumulation of forkhead box O3a (FOXO3a). The cytotoxic activity of OA coincided with upregulation of p38. Inhibition of p38 led to increase in FOXO3a and NAD+-dependent deacetylase sirtuin 6 expression. In vivo, OA inhibited tumor growth in colon cancer xenograft mice. Our results suggest concomitant induction of apoptosis and prosurvival mitophagy by OA in colon cancer via p38/FOXO3a/Sirt6 signaling. Additionally, our data demonstrate that OA can chemosensitize colon cancer cells to 5-fluorouracil (5-FU).

Luteolin ameliorates experimental colitis in mice through ERK-mediated suppression of inflammation, apoptosis and autophagy.

Ulcerative colitis (UC) is a chronic inflammatory disease with increasing incidence and prevalence worldwide. Currently used treatments of UC are unsatisfactory, while natural bioactive compounds are considered to be emerging therapeutic agents. Luteolin (Lut) is a natural compound with beneficial effects in a variety of diseases, however, its effect in UC has been poorly studied. In this study we investigated the effect of Lut in posttreatment and cotreatment of dextran sulfate sodium (DSS)-induced experimental colitis in mice. In addition, the role of extracellular signal-regulated kinases 1/2 (ERK1/2) in the mechanism of action of Lut in experimental colitis was investigated using the ERK inhibitor PD0325901. Lut attenuated symptoms of DSS-induced colitis in mice, ameliorated colon tissue damage and reduced inflammation, apoptosis and autophagy. The effect was more pronounced if Lut was administered simultaneously with DSS. The administration of ERK inhibitor exacerbated DSS-induced colitis symptoms and prevented the protective effects of Lut. The results provide new mechanistic details underlying the anti-inflammatory, anti-apoptotic and anti-autophagic effects of Lut through the activation of the ERK signaling pathway. This suggested that Lut can be used as a novel therapeutic candidate in the treatment of UC or could be used as a supplement to existing therapy.

Aucubin administered by either oral or parenteral route protects against cisplatin-induced acute kidney injury in mice.

Aucubin is pharmacologically active natural compound which possesses numerous beneficial properties. This study aimed to evaluate the protective effect of aucubin against cisplatin (CP)-induced acute kidney injury in mice and the mechanism of its action. Aucubin was administrated to mice orally or intraperitoneally (ip) (1.5 and 5 mg/kg) for two consecutive days, two days after ip injection of cisplatin (CP), 11 mg/kg. Treatment with aucubin by both routes of administration ameliorated histopathological changes and reduced elevated serum markers of kidney injury. CP administration increased renal expression of heme oxygenase-1 (HO-1) and 4-hydroxynonenal (4-HNE), as well as tumor necrosis factor-alpha (TNF-α), which was dose-dependently ameliorated by aucubin. Moreover, aucubin reduced increased renal expression of cleaved caspase-3 and -9 and decreased poly (ADP-ribose) polymerase (PARP) cleavage. Mechanistically, aucubin suppressed the activation of several signaling pathways involved in inflammation and apoptosis, including nuclear factor-kappa B (NF-κB), signal transducer and activator of transcription 3 (STAT3), Akt, extracellular signal-regulated kinase 1/2 (ERK1/2) and forkhead box O3a (FOXO3a). Parenteral application was marginally but statistically more effective in reducing CP-induced kidney injury than oral administration. The findings of this study suggest that aucubin acts as a protective agent against CP-induced nephrotoxicity, which should be further investigated.

Antitumor activity of luteolin in human colon cancer SW620 cells is mediated by the ERK/FOXO3a signaling pathway.

The aim of this study was to investigate the mechanism of the anticancer activity of luteolin in metastatic human colon cancer SW620 cells. Luteolin dose-dependently reduced the viability and proliferation of SW620 cells and increased the expression of antioxidant enzymes. The expression of antiapoptotic protein Bcl-2 decreased whereas the expression of proapoptotic proteins Bax and caspase-3 increased by luteolin treatment, resulting in increased poly (ADP-ribose) polymerase (PARP) cleavage and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positivity. Luteolin also increased the expression of autophagic proteins Beclin-1, autophagy-related protein 5 (Atg5) and microtubule-associated protein 1A/1B-light chain 3 beta-I/II (LC3B-I/II), while the usage of 3-methyladenine suggested a prosurvival role of autophagy. Moreover, treatment with luteolin induced reversal of the epithelial-mesenchymal transition process through the suppression of the wingless-related integration site protein (Wnt)/ß-catenin pathway. The cytotoxic activity of luteolin coincided with the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and forkhead box O3a (FOXO3a). Treatment with the mitogen-activated protein kinase kinase (MEK) inhibitor PD0325901 inhibited ERK-dependent FOXO3a phosphorylation, resulting in increased FOXO3a expression and apoptosis, with the suppression of autophagy. The results of the current study suggest the antitumor activity of luteolin in SW620 cells through the ERK/FOXO3a-dependent mechanism, as well as its antimetastatic potential.

Oleanolic acid attenuates cisplatin-induced nephrotoxicity in mice and chemosensitizes human cervical cancer cells to cisplatin cytotoxicity.

Oleanolic acid (OA) is a natural triterpenoid that possesses numerous beneficial health effects such as antioxidant, anti-inflammatory and anti-apoptotic activities. In this study, we investigated the therapeutic effect of OA (10 and 40 mg/kg) on cisplatin (CP)-induced (13 mg/kg) nephrotoxicity. Treatment with OA 40 mg/kg once daily for 2 days, 48 h after CP-intoxication, ameliorated the increased serum markers and histological features of kidney injury. CP administration increased renal expression of antioxidant and anti-inflammatory markers, which was reduced by OA. The increase in proapoptotic caspase-3 and -9 activations, with concomitant increase in poly (ADP-ribose) polymerase (PARP) cleavage, were dose-dependently inhibited by OA. Treatment with OA also ameliorated microtubule-associated protein 1A/1B-light chain 3B (LC3B)-II and autophagy-related protein (Atg) 5 expression induced by CP. The suppression of CP-induced oxidative stress, apoptosis, autophagy and inflammatory response by OA coincided with the inhibition of extracellular-regulated kinase (ERK) 1/2, signal transducer and activator of transcription (STAT) 3 and nuclear factor-kappa B (NF-κB). Interestingly, OA increased CP cytotoxicity in HeLa cervical cancer cells by inducing cytotoxic autophagy. The chemosensitization of HeLa cells to CP suggests a potential beneficial effect of OA in cervical cancer patients due to reduced CP dosage requirements, which requires further investigation.

Chlorogenic acid ameliorates experimental colitis in mice by suppressing signaling pathways involved in inflammatory response and apoptosis.

Chlorogenic acid (ChA) exhibits a multitude of positive health effects, however, the signaling mechanisms by which ChA could influence the inflammatory response in experimental colitis are unknown. To answer this question, we induced colitis in mice by administration of 2.5% dextran sulfate sodium (DSS) in drinking water for seven days. Oral administration of ChA significantly ameliorated clinical symptoms, improved disease activity index and colon shortening induced by DSS. Furthermore, ChA administration resulted in a suppression of phosphorylated extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun N-terminal kinases 1 and 2 (JNK1/2), Akt and signal transducer and activator of transcription 3 (STAT3) with concomitant upregulation of phosphatase and tensin homolog (PTEN) expression. Immunohistochemical analysis showed a dose-dependent decrease in expression and nuclear translocation of nuclear factor-kappa B (NF-κB) p65 subunit, which was accompanied by suppression of pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) expression. Induction of apoptosis and oxidative stress was attenuated in a dose-dependent manner by suppressing Bax, caspase-8, caspase-9 and heme oxygenase-1 (HO-1) protein expression in mice administrated with ChA. The results of the current study suggest that ChA could be useful for the treatment of inflammation and attenuating colitis severity by suppressing activation of pro-inflammatory and apoptotic signaling pathways.

Carvacrol induces cytotoxicity in human cervical cancer cells but causes cisplatin resistance: Involvement of MEK-ERK activation.

Carvacrol has been shown to possess anticancer activity, but the mechanism is unknown, as well as the possibility of interaction with anticancer drugs. The aim of this study was to investigate the role of mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling in carvacrol-induced human cervical cancer HeLa cell cytotoxicity. In addition, we studied sensitization of HeLa cells to cisplatin (CP) by carvacrol. Both carvacrol and CP showed dose-dependent cytotoxicity against HeLa cells and activated ERK1/2. The MEK inhibitor PD325901 suppressed ERK expression and further increased cytotoxicity of carvacrol but increased viability of CP-treated cells by modulating apoptosis. The MEK inhibitor also increased microtubule-associated protein 1A/1B-light chain 3 beta expression in CP treatment. Cotreatment with CP and carvacrol resulted in increased viability of the cancer cells compared with CP treatment, which was associated with the suppression of apoptosis. MEK inhibition decreased the cell viability, without changes in apoptosis. Concomitantly, carvacrol increased CP-induced expression of light chain 3 beta, which was enhanced by MEK inhibition. The results of the current study suggest the opposite role of ERK1/2 in carvacrol and CP-induced HeLa cell cytotoxicity. Interestingly, carvacrol induced CP resistance in HeLa cells through ERK1/2-independent suppression of apoptosis and ERK1/2-dependent modulation of autophagy.

Stevia and stevioside protect against cisplatin nephrotoxicity through inhibition of ERK1/2, STAT3, and NF-κB activation.

We investigated the effect of natural sweetener Stevia rebaudiana and its constituent stevioside in cisplatin (CP)-induced kidney injury. Male BALB/cN mice were orally administered 10, 20, and 50 mg/kg body weight of Stevia rebaudiana ethanol extract (SE) or stevioside 50 mg/kg, 48 h after intraperitoneal administration of CP (13 mg/kg). Two days later, CP treatment resulted in histopathological changes showing kidney injury. Increased expression of 4-hydroxynonenal (4-HNE), 3-nitrotyrosine (3-NT), and heme oxygenase-1 (HO-1) in mice kidneys suggested oxidative stress. CP treatment also increased renal expression of nuclear factor-kappaB (NF-κB) p65 subunit and phosphorylated inhibitor of NF-κB (IκBα), as well as expression of pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α). Induction of apoptosis and inhibition of the cell cycle in kidneys was evidenced by increased expression of p53, Bax, caspase-9, and p21, proteolytic cleavage of poly (ADP-ribose) polymerase (PARP), with concomitant suppression of Bcl-2 and cyclin D1 expression. The number of apoptotic cells in kidneys was also assessed. CP administration resulted in activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and signal transducer and activator of transcription 3 (STAT3). Both SE and stevioside attenuated CP nephrotoxicity by suppressing oxidative stress, inflammation, and apoptosis through mechanism involving ERK1/2, STAT3, and NF-κB suppression.

Carvacrol attenuates acute kidney injury induced by cisplatin through suppression of ERK and PI3K/Akt activation.

We investigated the mechanisms of renoprotective effects of carvacrol, a monoterpenoid compound, against cisplatin (CP)-induced kidney injury. Male BALB/cN mice were orally administered 1, 3, and 10 mg carvacrol/kg body weight for two days, 48 h after intraperitoneal injection of CP (13 mg/kg). Four days after CP administration, renal oxidative stress was evidenced by increased expression of 4-hydroxynonenal (4-HNE), 3-nitrotyrosine (3-NT), cytochrome P450 E1 (CYP2E1), and heme oxygenase-1 (HO-1). CP treatment increased the expression of phosphorylated nuclear factor-kappaB (p-NF-κB) p65 and tumor necrosis factor-alpha (TNF-α) in kidneys, suggesting inflammatory response. CP intoxication induced apoptosis and inhibition of the cell cycle in kidneys by increasing the expression of p53 and Bax and suppressing Bcl-2 and cyclin D1 expression. Concomitant increase in p21 and proliferating cell nuclear antigen (PCNA) expression suggested enhanced DNA repair process. CP administration also resulted in activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) with concomitant induction of phosphorylated Akt and suppression of phosphatase and tensin homolog (PTEN) expression. All these changes were dose-dependently restored by carvacrol. The results of the current study suggest that carvacrol could attenuate CP-induced acute renal injury by suppressing oxidative stress, apoptosis, and inflammation through modulation of the ERK and PI3K/Akt pathways.

A comprehensive overview of hepatoprotective natural compounds: mechanism of action and clinical perspectives.

Hepatoprotective effects of natural compounds have been frequently attributed to their antioxidant properties and the ability to mobilize endogenous antioxidant defense system. Because of involvement of oxidative stress in virtually all mechanisms of liver injury, it is a reasonable presumption that antioxidant properties of these compounds may play a key role in the mechanism of their hepatoprotective activity. Nevertheless, growing evidence suggests that other pharmacological activities of natural compounds distinct from antioxidant are responsible for their therapeutic effects. In this review, we discussed currently known molecular mechanisms of the hepatoprotective activity of 27 most intensively studied phytochemicals. These compounds have been shown to possess anti-inflammatory, antisteatotic, antiapoptotic, cell survival and antiviral activity through interference with multiple molecular targets and signaling pathways. Additionally, antifibrotic properties of phytochemicals have been closely associated with apoptosis of hepatic stellate cells and stimulation of extracellular matrix degradation. However, although these compounds exhibit a pronounced hepatoprotective effects in animal and cell culture models, the lack of clinical studies remains a bottleneck for their official acceptance by medical experts and physicians. Therefore, controlled clinical trials have an imperative in confirmation of the therapeutic activity of potentially hepatoprotective compounds. Understanding the principles of the hepatoprotective activity of phytochemicals could guide future drug development and help prevention of clinical trial failure. Also, the use of new delivery systems that enhances bioavailability of poorly water soluble compounds may improve the results already obtained. Most importantly, available data suggest that phytochemicals possess a various degree of modulation of specific signaling pathways, pointing out a need for usage of combinations of several hepatoprotective compounds in both experimental studies and clinical trials.

Oral administration of oleuropein attenuates cisplatin-induced acute renal injury in mice through inhibition of ERK signaling.

SCOPE: Oleuropein possesses numerous health beneficial effects. We investigated the renoprotective effects of oleuropein against cisplatin (CP) induced kidney injury. METHODS AND RESULTS: Male BALB/cN mice were orally gavaged with 5, 10 and 20 mg oleuropein/kg body weight for 2 days, 48 h after intraperitoneal injection of CP (13 mg/kg). Four days after CP administration, serum creatinine and blood urea nitrogen (BUN) levels were significantly elevated, with histopathological changes in renal tissue. In addition, renal oxidative stress was evidenced by increased expression of 3-nitrotyrosine (3-NT), 4-hydroxynonenal (4-HNE), cytochrome P450 E1 (CYP2E1) and heme oxygenase-1 (HO-1). The expression of nuclear factor-kappaB (NF-κB) p65, phospho-p65, tumor necrosis factor-alpha (TNF-α) and cyclooxygenase-2 (COX-2) in the kidneys increased upon CP treatment, suggesting renal inflammation. CP intoxication increased the expression of p53, Bax and caspase-3 and induced apoptosis in the kidneys. CP administration also resulted in enhanced phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). All these effects were dose dependently diminished by oleuropein. Oral administration of PD0325901, an MEK inhibitor, coincided with the oleuropein-mediated suppression of apoptotic, inflammatory and antioxidant markers. CONCLUSION: The results of the current study suggest that oleuropein attenuated CP-induced acute renal injury, which was mediated through the inhibition of ERK signaling.

Nephroprotective activities of rosmarinic acid against cisplatin-induced kidney injury in mice.

Rosmarinic acid (RA) is a natural phenolic compound with a broad range of applications, from food preservatives to cosmetics. Increasing amounts of evidence suggests its beneficial effects against various pathological conditions. The aim of this study was to investigate the therapeutic activity of rosmarinic acid (RA) against cisplatin (CP)-induced nephrotoxicity. RA was administered by oral gavage at doses of 1, 2 and 5mg/kg for two successive days, 48 h after intraperitoneal CP injection (13 mg/kg). Twenty four hours later, mice were sacrificed. Treatment with RA significantly ameliorated histopathological changes and the increase in serum creatinine and blood urea nitrogen (BUN) induced by CP. Oxidative stress induced by CP, evidenced by increased renal 4-hydroxynonenal (4-HNE), cytochrome P450 2E1 (CYP2E1) and heme oxygenase (HO-1) expression, was significantly reduced by RA administration. Moreover, RA inhibited the expression of nuclear factor-kappaB (NF-κB) and tumor necrosis factor-α (TNF-α), indicating the inhibition of inflammation. Additionally, RA exhibited antiapoptotic activity through the reduction of p53, phosphorylated p53 and active caspase-3 expression in the kidneys. These findings show that RA ameliorates CP-induced oxidative stress, inflammation and apoptosis in the kidneys. The nephroprotective activity of RA could be, at least in part, attributed to reduced CYP2E1 expression.