Possible involvement of oxidative stress in cisplatin-induced apoptosis in LLC-PK1 cells

Ammonium tetrathiomolybdate relieves oxidative stress in cisplatin-induced acute kidney injury via NRF2 signaling pathway

Cisplatin is an efficient chemotherapeutic agent for various solid tumors, but its usage is restricted by nephrotoxicity. A single dose of cisplatin can cause acute kidney injury (AKI), which is characterized by rapid reduction in kidney function. However, the current therapies, such as hydration, are limited. It is vital to develop novel therapeutic reagents that have both anticancer and renoprotective properties. The objective of this study was to determine whether ammonium tetrathiomolybdate (TM), a copper chelator used to treat cancer and disorders of copper metabolism, may offer protection against cisplatin-induced AKI. In this study, we demonstrated that TM treatment had antioxidative effects and mitigated cisplatin-induced AKI both in vivo and in vitro. Mechanically, TM inhibited NRF2 ubiquitination, which activated the NRF2 pathway in HK-2 cells and promoted the expression of target genes. It should be noted that the protective effect conferred by TM against cisplatin was compromised by the knockdown of the NRF2 gene. Furthermore, TM selectively activated the NRF2 pathways in the liver and kidney. The current study provided evidence for additional clinical applications of TM by showing that it activates NRF2 and has a favorable therapeutic impact on cisplatin-induced AKI.

The dark side of miracle plant-Aloe vera: a review

BACKGROUND

Aloe vera (Aloe barbadensis Miller), commonly known as Ghritkumari/Gwarpatha, is a member of the Liliaceae family, used in the traditional medicine system for ages. Aloe vera has made its importance as a therapeutic agent, acting as a cure for various diseases such as skin problems, lungs, and heart disorders, diabetes, ulcers, various microbial infections, and asthma. Despite its tremendous health benefits, the dark side of the plant is a reason of concern as there are several active compounds present in the plant, raising questions on its safe oral consumption and application.

METHODS AND RESULTS

The literature review was compiled from information resourced from various national and international journals available at Google Scholar and curated with Mendeley. The data mining was carried out during the period of January to May 2021. This study explored and summarized the dark side of Aloe vera, subjected to various secondary metabolites present in it. Aloin, the most active compound of Aloe vera, is a type of anthraquinone metabolized by human gut microflora, resulting in the formation of aloe-emodin anthraquinone, later being associated with several harmful effects such as carcinogenicity, genotoxicity, nephrotoxicity, and purgative. Besides this, several alkaloids and polysaccharides present in the plant are reported to cause hepatotoxicity and male infertility, respectively.

CONCLUSIONS

The harmful effects of the plants are not adequately discovered yet; hence there is a need to come up with some mechanism to understand and suppress the formation of such toxic compounds completely. This review examined the botany, active compounds, and adverse clinical effects in the range of metabolites associated with this herb - "Aloe vera".

The protective impacts of Spirulina platensis against cisplatin-induced renal injury through the regulation of oxidative stress, pro-inflammatory cytokines and Bax/Bcl2

One of the main antineoplastic chemotherapy medications is cisplatin, of which nephropathy is a major side effect. In this current study, we aim to investigate the molecular protective effect of Spirulina platensis (SP) on cisplatin-induced nephrotoxicity. In total, 48 healthy male albino rats were allocated into 4 groups. Group 1 received saline intraperitoneally (IP) twice per week (normal rats). Group 2 received SP (100 mg/kg BW orally). Group 3 were injected with cisplatin (1.5 mg/kg IP) twice per week. Group 4 received SP and on the 4th day received cisplatin (1.5 mg/kg IP) for 21 days. After 3 weeks of experiment, blood and renal tissues were taken for serum analysis, gene expression using qRT-polymerase chain reaction, and renal histopathology. As per our findings, it was found that SP significantly ameliorated the alterations in body weight, relative kidney weight, and the disturbance in examined renal markers. Furthermore, SP recovered and restored cisplatin-induced oxidative stress biomarkers (MDA and NO) and antioxidant activity (SOD and GSH) and cisplatin-induced upregulation in the gene expression of TNF-α, inducible nitric oxide synthase, TGF1-β, IL-1β, and IL-6. Interestingly, these gene expressions were ameliorated by the SP pre-administration. Furthermore, cisplatin upregulated pro-apoptotic gene Bax, whereas it downregulated anti-apoptotic gene Bcl2. Interestingly, SP mitigated this alteration in apoptosis and anti-apoptotic associated genes. Renal histopathology revealed the protective impacts of SP against cisplatin-induced severe glomerular congestion, hemorrhage, inflammatory cell infiltration, degeneration, and severe necrosis in renal glomeruli and tubules. In conclusion, SP has a protective effect against cisplatin-induced renal damage through modulating oxidative stress and anti-inflammatory, anti-necrotic, and anti-apoptotic-associated genes.

Hepatoprotective effect of ferulic acid and/or low doses of γ-irradiation against cisplatin-induced liver injury in rats

The therapeutic efficacy of cisplatin (CIS) is limited owing to its hepatotoxic side effects. The current study aimed to investigate the protective impact of ferulic acid (FA) and low-doses of γ-irradiation (LDR) against CIS-prompted hepatotoxicity in rats. Adult male Swiss albino rats were divided into eight groups: untreated group; FA, LDR, and CIS treated groups; and combinations of one or more of the above treatments. Post-treatment analyses included measuring redox markers like SOD and CAT activity, NO free radical content, and lipid peroxidation in liver tissue. Serum aminotransferase activities were also determined. Additionally, gene transcript levels of liver NF-ҡB-P65, caspase-1, COX-2, and IL-1β were quantified. Moreover, immunohistochemistry for caspase-3 and histopathological examinations were estimated in liver tissue. Our findings revealed increased levels of oxidative stress along with a significant reduction in anti-oxidative responses and a significant increase in serum aminotransferase activities in the CIS-intoxicated group. A similar increase was also observed in COX-2 and IL-1β transcript levels and caspase-3 enzyme activity, besides a decrease in transcript levels of NF-ҡB-p65 and caspase-1, indicating an overall inflammatory trend and an increase in the apoptotic shift. The co-administration of FA and/or treatment with LDR has ameliorated the hepatotoxic effect induced by CIS. The histopathological investigation of liver tissues confirmed this ameliorating action of these adjuvant therapies against CIS toxicity. In conclusion, it is plausible to suggest that the hepatoprotective effects of co-administration of FA and/or LDR against CIS-induced hepatotoxicity are attributed to the possession of anti-oxidative, anti-inflammatory, and anti-apoptotic capabilities.

Regression Modeling of the Antioxidant-to-Nephroprotective Relation Shows the Pivotal Role of Oxidative Stress in Cisplatin Nephrotoxicity

The clinical utility of the chemotherapeutic drug cisplatin is significantly limited by its nephrotoxicity, which is characterized by electrolytic disorders, glomerular filtration rate decline, and azotemia. These alterations are consequences of a primary tubulopathy causing injury to proximal and distal epithelial cells, and thus tubular dysfunction. Oxidative stress plays a role in cisplatin nephrotoxicity and cytotoxicity, but its relative contribution to overall toxicity remains unknown. We studied the relation between the degree of oxidative reduction (provided by antioxidant treatment) and the extent of nephrotoxicity amelioration (i.e., nephroprotection) by means of a regression analysis of studies in animal models. Our results indicate that a linear relation exists between these two parameters, and that this relation very nearly crosses the value of maximal nephroprotection at maximal antioxidant effect, suggesting that oxidative stress seems to be a pivotal and mandatory mechanism of cisplatin nephrotoxicity, and, hence, an interesting, rationale-based target for clinical use. Our model also serves to identify antioxidants with enhanced effectiveness by comparing their actual nephroprotective power with that predicted by their antioxidant effect. Among those, this study identified nanoceria, erythropoietin, and maltol as highly effective candidates affording more nephroprotection than expected from their antioxidant effect for prospective clinical development.

Necrostatins regulate apoptosis, necroptosis, and inflammation in cisplatin-induced nephrotoxicity in LLC-PK1 cells

Acute kidney injury (AKI) is a common clinical problem that is associated with high mortality due to multiple complex mechanisms. Cisplatin is the most important and highly effective chemotherapeutic agent used for the treatment of various solid tumors; however, it is associated with dose-dependent adverse effects, particularly in the kidney where it can cause severe nephrotoxicity. The pathophysiological basis of cisplatin-induced nephrotoxicity has been investigated over the last few decades, and the key pathological occurrences in cisplatin nephrotoxicity include renal tubular cell injury and death. Necrostatin-1 (Nec-1) has been confirmed to act as a specific and potent small-molecule inhibitor of necroptosis. However, the effects of three structurally distinct necrostatins on cisplatin-induced nephrotoxicity remain ambiguous. The aim of this study was to determine if three types of necrostatins (Nec-1, Nec-3-A, and/or Nec-3-B) can exert protective effects in regard to the AKI induced by cisplatin. Our results indicated that necrostatins can prevent cisplatin induced nephrotoxicity via modulating apoptotic pathways through the suppression of cleaved caspase-3 and also by influencing the function of mitogen-activated protein kinase pathway members, including extracellular signal-regulated kinases, c-Jun N-terminal kinases, and p38, in the renal tubular epithelial cell line LLC-PK1. These findings suggest that necrostatins exert beneficial anti-apoptotic effects in the context of AKI induced by cisplatin.

Concentration Dependence of the Antioxidant and Prooxidant Activity of Trolox in HeLa Cells: Involvement in the Induction of Apoptotic Volume Decrease

Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a hydrophilic analog of vitamin E, is known for its strong antioxidant activity, being a high radical scavenger of peroxyl and alkoxyl radicals. Under particular conditions, Trolox may also exhibit prooxidant properties. The present work aimed at studying the dual antioxidant/prooxidant behavior of Trolox over a wide range of concentrations (from 2.5 to 160 µM) in HeLa cells. In particular, the study addressed the dose-dependent effects of Trolox on the oxidative cell status and vitality of HeLa cells, focusing on the potential role of the vitamin E analog in the induction of one of the first steps of the apoptotic process, Apoptotic Volume Decrease (AVD). In HeLa cells, Trolox showed significant antioxidant activity, expressed as the ability to reduce the endogenous ROS production detected by the ROS-sensitive probe 5-(and-6)-chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate (CM-H₂DCFDA), at low concentrations (range: 2.5–15 µM), but exerted a dose-dependent prooxidant effect at higher concentrations after 24 h exposure. The prooxidant effect was paralleled by the reduction in cell viability due to the induction of the apoptotic process. The dual behavior, antioxidant at lower concentrations and prooxidant at higher concentrations, was evident also earlier after 2 h incubation, and it was paralleled by the isotonic shrinkage of the cells, ascribed to AVD. The use of SITS, known Cl⁻ channel blocker, was able to completely inhibit the Trolox-induced isotonic cell shrinkage, demonstrating the involvement of the vitamin E analog in the alteration of cell volume homeostasis and, in turn, in the AVD induction. In conclusion, the study shed light on the concentration dependence of the Trolox antioxidant/prooxidant activity in HeLa cells and revealed its role in the induction of one of the first events of apoptosis, AVD, at high concentrations.

Platycodin D suppresses cisplatin-induced cytotoxicity by suppressing ROS-mediated oxidative damage, apoptosis, and inflammation in HEK-293 cells

Cisplatin, a proven effective chemotherapeutic agent, has been used clinically to treat malignant solid tumors, whereas its clinical use is limited by serious side effect including nephrotoxicity. Platycodin D (PD), the major and marked saponin isolated from Platycodon grandiflorum, possesses many pharmacological effects. In this study, we evaluated its protective effect against cisplatin-induced human embryonic kidney 293 (HEK-293) cells injury and elucidated the related mechanisms. Our results showed that PD (0.25, 0.5, and 1 μM) can dose-dependently alleviate oxidative stress by decreasing malondialdehyde and reactive oxygen species, while increasing the levels of glutathione, superoxide dismutase, and catalase. Moreover, the elevation of apoptosis including Bax, Bad, cleaved caspase-3,-9, and decreased protein levels of Bcl-2, Bcl-XL induced by cisplatin were reversed after PD treatment. Importantly, PD pretreatment can also regulate PI3K/Akt and ERK/JNK/p38 signaling pathways. Furthermore, PD was found to reduce NF-κB-mediated inflammatory relative proteins. Our finding indicated that PD exerted significant effects on cisplatin induced oxidative stress, apoptosis and inflammatory, which will provide evidence for the development of PD to attenuate cisplatin-induced nephrotoxicity.

Protective effect of ginsenoside Rk1, a major rare saponin from black ginseng, on cisplatin-induced nephrotoxicity in HEK-293 cells

Cisplatin, as one of the most effective chemotherapeutic agents, its clinical use is limited by serious side effect of nephrotoxicity. Cisplatin-induced nephrotoxicity is closely related to apoptosis induction and activation of caspase. The present study aimed to explore the potential protective effect of ginsenoside Rk1 (Rk1), a rare ginsenoside generated during steaming ginseng, on cisplatin-induced nephrotoxicity and the underlying mechanisms in human embryonic kidney 293 (HEK-293) cells. Our results showed that the reduced cell viability induced by cisplatin could significantly recover by Rk1. Furthermore, glutathione (GSH) as an oxidative index, was elevated and the lipid peroxidation product malondialdehyde (MDA) was significantly decreased after Rk1 treatment compared to the cisplatin group. Additionally, Rk1 can also decrease the ROS fluorescence expression and increase the protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) compared to the cisplatin group, which suggested a suppression of oxidative response. More importantly, the cisplatin-induced elevated protein levels of Bax, cleaved caspase-3, cleaved caspase-9, and decreased protein level of Bcl-2 were reversed after treatment with Rk1. Our results elucidated the possible protective mechanism of Rk1 for the first time, which may involve in its anti-oxidation and anti-apoptosis effects.

Effects of cisplatin-5-fluorouracil combination therapy on oxidative stress, DNA damage, mitochondrial apoptosis, and death receptor signalling in retinal pigment epithelium cells

AIM

Combination therapies of cisplatin with 5-FU (PF) are an effective solution and have been widely used for the treatment of various categories of cancer including anal, gastrointestinal, and oral cancer, as well as head and neck tumors. The effects of combined PF treatment on vital intracellular signalling pathways in nontargeted cells remain unclear. The aim of this study is to explain the possible mechanisms by which combined PF treatment results in retinal toxicity and to investigate the effects of PF on important vital signalling pathways in ARPE 19 retinal pigmented epithelial cells.

MATERIALS AND METHODS

We analysed the cellular and molecular effects of PF on cell viability, oxidative stress, gene repair response, and induction of apoptosis in ARPE 19 cells using molecular probe fluorescent staining, cell cytometer, RAPD, qRT-PCR, and western blot assays.

RESULTS

We determined that PF causes excessive generation of reactive oxygen species (ROS) and prevents ROS scavenging by suppressing antioxidant systems. We found induction of DNA damage, particularly mismatch and double strand break repair, in ARPE 19 cells treated with PF. In this study, PF also induced both the intrinsic apoptosis pathway and death receptor signalling in ARPE 19 cells.

CONCLUSIONS

Our data proved that PF causes cytotoxicity and genotoxicity, at both the cellular and molecular levels, in ARPE 19 cells following particularly prolonged treatment (48 h). Additionally, our results suggest key molecular signals for prevention strategies that can be developed to reduce the severe side effects of PF chemotherapy.

Renoprotective Effects of Hypoxylonol C and F Isolated from Hypoxylon truncatum against Cisplatin-Induced Cytotoxicity in LLC-PK1 Cells

Although cisplatin is the standard platinum-based anticancer drug used to treat various solid tumors, it can cause damage in normal kidney cells. Protective strategies against cisplatin-induced nephrotoxicity are, therefore, clinically important and urgently required. To address this challenge, we investigated the renoprotective effects of Hypoxylontruncatum, a ball-shaped wood-rotting fungus. Chemical investigation of the active fraction from the methanol extract of H.truncatum resulted in the isolation and identification of the renoprotective compounds, hypoxylonol C and F, which ameliorated cisplatin-induced nephrotoxicity to approximately 80% of the control value at 5 μM. The mechanism of this effect was further investigated using hypoxylonol F, which showed a protective effect at the lowest concentration. Upregulated phosphorylation of p38, extracellular signal-regulated kinases, and c-Jun N-terminal kinases following cisplatin treatment were markedly decreased after pre-treatment with hypoxylonol F. In addition, the protein expression level of cleaved caspase-3 was significantly reduced after co-treatment with hypoxylonol F. These results show that blocking the mitogen-activated protein kinase signaling cascade plays a critical role in mediating the renoprotective effect of hypoxylonol F isolated from H.truncatum fruiting bodies.

A H 2 S Donor GYY4137 Exacerbates Cisplatin-Induced Nephrotoxicity in Mice

Accumulating evidence demonstrated that hydrogen sulfide (H₂S) is highly involved in inflammation, oxidative stress, and apoptosis and contributes to the pathogenesis of kidney diseases. However, the role of H₂S in cisplatin nephrotoxicity is still debatable. Here we investigated the effect of GYY4137, a novel slow-releasing H₂S donor, on cisplatin nephrotoxicity in mice. Male C57BL/6 mice were pretreated with GYY4137 for 72 h prior to cisplatin injection. After cisplatin treatment for 72 h, mice developed obvious renal dysfunction and kidney injury as evidenced by elevated blood urea nitrogen (BUN) and histological damage. Consistently, these mice also showed increased proinflammatory cytokines such as TNF-α, IL-6, and IL-1β in circulation and/or kidney tissues. Meanwhile, circulating thiobarbituric aid-reactive substances (TBARS) and renal apoptotic indices including caspase-3, Bak, and Bax were all elevated. However, application of GYY4137 further aggravated renal dysfunction and kidney structural injury in line with promoted inflammation, oxidative stress, and apoptotic response following cisplatin treatment. Taken together, our results suggested that GYY4137 exacerbated cisplatin-induced nephrotoxicity in mice possibly through promoting inflammation, oxidative stress, and apoptotic response.

Oral administration of Nigella sativa oil ameliorates the effect of cisplatin on membrane enzymes, carbohydrate metabolism and oxidative damage in rat liver

Cisplatin (CP) is a potent anti-cancer drug widely used against solid tumors. However, it exhibits pronounced adverse effects including hepatotoxicity. Several strategies were attempted to prevent CP hepatotoxicity but were not found suitable for therapeutic application. Nigella sativa has been shown to prevent/reduce the progression of certain type of cardiovascular, kidney and liver diseases. Present study investigates whether N. sativa oil (NSO) can prevent CP induced hepatotoxic effects. Rats were divided into four groups viz. control, CP, NSO and CPNSO. Animals in CPNSO and NSO group were administered NSO (2 ml/kg bwt, orally) with or without single hepatotoxic dose of CP (6 mg/kg bwt, i.p.) respectively. CP hepatotoxicity was recorded by increased serum ALT and AST activities. CP treatment caused oxidant/antioxidant imbalances as reflected by increased lipid peroxidation and decreased enzymatic and non-enzymatic antioxidants. Furthermore, the activities of various carbohydrate metabolism and membrane enzymes were altered by CP treatment. In contrast, NSO administration to CP treated rats, markedly ameliorated the CP elicited deleterious alterations in liver. Histopathological observations showed extensive liver damage in CP treated animals while greatly reduced tissue injury in CPNSO group. In conclusion, NSO appears to protect CP induced hepatotoxicity by improving energy metabolism and strengthening antioxidant defense mechanism.

Protective Effects of Processed Ginseng and Its Active Ginsenosides on Cisplatin-Induced Nephrotoxicity: In Vitro and in Vivo Studies

Although cisplatin can dramatically improve the survival rate in cancer patients, its use is limited by its nephrotoxicity. Previous investigations showed that Panax ginseng contains components that exhibit protective activity against cisplatin-induced nephropathy. The aim of the present study is to investigate the effect of microwave-assisted processing on the protective effect of ginseng and identify ginsenosides that are active against cisplatin-induced kidney damage to evaluate the potential of using ginseng in the management of nephrotoxicity. The LLC-PK1 cell damage by cisplatin was significantly decreased by treatment with microwave-processed ginseng (MG) and ginsenosides Rg3, Rg5, and Rk1. Reduced expression of p53 and c-Jun N-terminal kinase proteins by cisplatin in LLC-PK1 cells was markedly ameliorated after Rg3 and Rg5/Rk1 treatment. Additionally, elevated expression of cleaved caspase-3 was significantly reduced by ginsenosides Rg5, Rk1, and with even greater potency, Rg3. Moreover, MG and its fraction containing active ginsenosides showed protective effects against cisplatin-induced nephropathy in mice. We found that ginsenosides Rg3, Rg5, and Rk1 generated during the heat treatment of ginseng ameliorate renal damage by regulating inflammation and apoptosis. Results of current experiments provide evidence of the renoprotective effects and therapeutic potential of MG and its active ginsenosides, both in vitro and in vivo.

The synthesis of sulforaphane analogues and their protection effect against cisplatin induced cytotoxicity in kidney cells

A series of sulforaphane analogues were synthesized with various amines by treatment of carbon disulfide followed by Boc₂O and DMAP. These synthesized sulforaphane analogues were tested on cisplatin treated cultured LLC-PK1 kidney cell line. Among these analogues, several compounds including SF5 show a potent effect on kidney cell protection assay at the concentration of 2.5 μM. Further studies with compound SF5 revealed that the kidney cell protection effect was related by inhibiting the apoptosis pathway through JNK-p53-caspase apoptotic cascade. Compound SF5 may be considered as a promising candidate for the development of new kidney protection agent against drug induced acute kidney disease.

Protective effect of Hygrophila spinosa against cisplatin induced nephrotoxicity in rats

Objective:

To evaluate the nephroprotective effect of methanolic extract of Hygrophila spinosa (HSME) (Acanthaceae) in (CP)-induced acute renal failure in rats.

Materials and Methods:

HSME (250 mg/kg and 500 mg/kg body weight), were administered orally to male wistar albino rats.CP was used to induce acute renal failure. The parameters studied included blood urea and serum creatinine and malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and GSH peroxidase activities. Histopathological examination was also carried out.

Results:

The results revealed that HSME pretreatment signiûcantly reduced blood urea and serum creatinine levels elevated by CP administration. Furthermore, HSME signiûcantly attenuated CP-induced increase in MDA and decrease in reduced GSH, and CAT and SOD and GSH peroxidase activities in renal cortical homogenates. Additionally, histopathological examination showed that HSME markedly ameliorated CP-induced renal tubular necrosis.

Conclusion:

The results indicate that the aerial parts of H. spinosa are endowed with nephroprotective activity.

Auranofin promotes mitochondrial apoptosis by inducing annexin A5 expression and translocation in human prostate cancer cells

Auranofin is a lipophilic gold compound with anti-inflammatory and immunosuppressive properties. This compound also exerts antiproliferative effects in several human cancer cell lines. Although auranofin induces apoptosis in human cancer cells, the underlying mechanisms remain unclear. This study investigated auranofin-mediated inhibition of cell growth and induction of mitochondrial apoptosis in PC3 human prostate cancer cells. Treatment with auranofin significantly inhibited cell viability with an IC50 value of 2.5 μM after 24 h. In particular, when cells were treated with 2.5 μM auranofin, there was a 2.2-fold increase in apoptotic cells compared to untreated cells. Auranofin activated caspase-3 and -8 in a concentration-dependent manner and decreased the levels of mitochondrial anti-apoptotic factors, such as Bcl-2 and Bcl-xL. In addition, auranofin enhanced oligomerization of the voltage-dependent anion channel (VDAC) in a concentration- and time-dependent manner. Interestingly, auranofin significantly enhanced annexin A5 mRNA and protein expression and promoted annexin A5 translocation into the mitochondria. In order to characterize the function of annexin A5 in auranofin-induced mitochondrial apoptosis, annexin A5 was depleted using siRNA. Annexin A5 siRNA suppressed auranofin-mediated annexin A5 expression and VDAC oligomerization. Accordingly, annexin A5 depletion rescued auranofin-induced apoptosis, which may be mediated by caspase-3 activation. In conclusion, the present findings suggest that auranofin induces mitochondrial apoptosis through induction of annexin A5 expression and translocation as well as VDAC oligomerization in human prostate cancer cells.

Signalling mechanisms involved in renal pathological changes during cisplatin-induced nephropathy

CONTEXT

Cisplatin, a coordination platinum complex, is used as a potential anti-neoplastic agent, having well recognized DNA-damaging property that triggers cell-cycle arrest and cell death in cancer therapy. Beneficial chemotherapeutic actions of cisplatin can be detrimental for kidneys.

BACKGROUND

Unbound cisplatin gets accumulated in renal tubular cells, leading to cell injury and death. This liable action of cisplatin on kidneys is mediated by altered intracellular signalling pathways such as mitogen-activated protein kinase (MAPK), extracellular regulated kinase (ERK), or C- Jun N terminal kinase/stress-activated protein kinase (JNK/SAPK). Further, these signalling alterations are responsible for release and activation of tumour necrosis factor (TNF-α), mitochondrial dysfunction, and apoptosis, which ultimately cause the renal pathogenic process. Cisplatin itself enhances the generation of reactive oxygen species (ROS) and activation of nuclear factor-κB (NF-κB), inflammation, and mitochondrial dysfunction, which further leads to renal apoptosis. Cisplatin-induced nephropathy is also mediated through the p53 and protein kinase-Cδ (PKCδ) signalling pathways.

OBJECTIVE

This review explores these signalling alterations and their possible role in the pathogenesis of cisplatin-induced renal injury.

Dietary flaxseed oil supplementation ameliorates the effect of cisplatin on brush border membrane enzymes and antioxidant system in rat intestine

Cisplatin (CP; cis-diamminedichloroplatinum II) is a drug widely used against different types of solid tumors. Patients receiving CP, however, experience very profound and long lasting gastrointestinal symptoms. Recently, ω-3 polyunsaturated fatty acid-enriched flaxseed/flaxseed oil (FXO) has shown numerous health benefits. The present study was undertaken to investigate whether FXO can prevent CP-induced adverse biochemical changes in the small intestine of rats. A single intraperitoneal dose of CP (6 mg/kg body weight) was administered to male Wistar rats fed with control diet (CP group) and FXO diet (CPFXO group). Administration of CP led to a significant decline in the specific activities of brush border membrane enzymes both in the mucosal homogenates and in the isolated membrane vesicles. Lipid peroxidation and total sulfhydryl groups were altered upon CP treatment, indicating the generation of oxidative stress. The activities of SOD, catalase and glutathione peroxidase also decreased in CP-treated rats. In contrast, dietary supplementation of FXO prior to and following CP treatment significantly attenuated the CP-induced changes in all these parameters. FXO feeding markedly enhanced resistance to CP-elicited adverse gastrointestinal effects. The results suggest that FXO owing to its intrinsic biochemical/antioxidant properties is an effective agent in reducing the adverse effects of CP on intestine.

Cisplatin-induced ototoxicity is mediated by nitroxidative modification of cochlear proteins characterized by nitration of Lmo4

Tyrosine nitration is an important sequel of cellular signaling induced by reactive oxygen species. Cisplatin is an anti-neoplastic agent that damages the inner ear through reactive oxygen species and by the formation of DNA adducts. This study reveals a correlation between cisplatin-mediated hearing loss and nitroxidative modification of cochlear proteins and is the first to report nitration of Lmo4. Cisplatin induced a dose-dependent increase in hearing loss in Wistar rats. A 10-15-dB decrease in distortion product amplitude and massive loss of outer hair cells at the basal turn of the cochlea was observed 3 days post-treatment after a 16 mg/kg dose. Cisplatin induced nitration of cellular proteins within the organ of Corti, spiral ganglion, and stria vascularis, which are known targets of cisplatin ototoxicity. Nitration of a 76-kDa cochlear protein correlated with cisplatin dose. The nitrated protein was identified as Lmo4 (LIM domain only 4) by MALDI-TOF (matrix-assisted laser desorption/ionization time of flight) mass spectrometry and confirmed by reciprocal immunoprecipitation and immunoblotting. Co-localization of nitrotyrosine and Lmo4 was particularly high in outer hair cell nuclei after cisplatin treatment. Cochlear levels of Lmo4 were decreased in rats treated with cisplatin. In vitro studies supported the repression of Lmo4 in nitroxidative conditions and the induction of apoptosis upon repression of Lmo4. Inhibition of cochlear protein nitration prevented cisplatin-induced hearing loss. As Lmo4 is a transcriptional regulator that controls the choice between cell survival and cell death, these results support the hypothesis that nitration of Lmo4 influences cisplatin-induced ototoxicity.

P-glycoprotein depresses cisplatin sensitivity in L1210 cells by inhibiting cisplatin-induced caspase-3 activation

Multidrug resistance (MDR) is a phenomenon in which cells become resistant to cytostatic drugs and other substances with diverse chemical structures and cytotoxicity mechanisms. The most often observed molecular mechanism for MDR includes high levels of P-glycoprotein (P-gp)--an ABCB1 member of the ABC drug transporter family. Overexpression of P-gp in neoplastic tissue is an obstacle to chemotherapeutic treatment. Herein, we were focused on differences in apoptosis induced by cisplatin (no substrate for P-gp) between P-gp-positive and P-gp-negative L1210 cells. P-gp-positive cells were obtained by either L1210 cell adaptation to vincristine (R) or L1210 cell transfection with the human gene for P-gp (T) and compared with parental L1210 cells (S). R and T cells were more resistant to CisPt than S cells. R and T cell resistance to CisPt-induced apoptosis could not be reversed by verapamil (a well-known P-gp inhibitor), which excludes P-gp transport activity as a cause of CisPt resistance. CisPt induced a more pronounced entry into apoptosis in S than R and T cells, which was measured using the annexin-V/propidium iodide apoptosis kit. CisPt induced more pronounced caspase-3 activation in S than R and T cells. CisPt did not induce changes in the P-gp protein level for R and T cells. While similar levels of Bax and Bcl-2 proteins were observed in P-gp-negative and P-gp-positive cells, CisPt induced a more significant decrease in Bcl-2 levels for S cells than P-gp-positive cells. Expression of p53 and its molecular chaperone Hsp90 were more pronounced in R and T than S cells. Moreover, CisPt enhanced the upregulation of p53 and Hsp90 in R and T cells to a higher degree than S cells. Apoptosis was shown to be the prevalent mode of cell death in S, R and T cells by the typical DNA fragmentation and cell ultrastructure changes. All of the above findings indicate that P-gp, independent of its drug efflux activity, induced changes in cell regulatory pathways that confer a partial loss of cisplatin sensitivity.

Protective effect of recombinant human erythropoeitin against cisplatin cytotoxicity and genotoxicity in cultured Vero cells

Cisplatin is an effective agent against various solid tumors. Despite its effectiveness, the dose of cisplatin that can be administered is limited by its nephrotoxicity. Therefore, strategies for minimising the toxicity of cisplatin are of a clinical interest. The aim of this study was to investigate the protective effect of recombinant human erythropoietin (rhEPO) against the cytotoxicity and apoptosis induced by cisplatin in cultured Vero cells. Three types of treatments were performed: (i) cells were treated with rhEPO 24 h before exposure to cisplatin (pre-treatment), (ii) cells were treated with rhEPO and cisplatin simultaneously (co-treatment), (iii) cells were treated with rhEPO 24 h after exposure to cisplatin (post-treatment). Our results showed that rhEPO reduced cisplatin-induced cell mortality. Besides, rhEPO administration prevented cisplatin-induced DNA damage. Furthermore, rhEPO decreased the caspase-3 activity and pro-apoptotic factors levels (p53 and Bax) induced by cisplatin. It increased also the expression of the anti-apoptotic factor Bcl2 in Vero cells. Altogether, our results suggest a protective action of rhEPO against cisplatin cytotoxicity and genotoxicity via an anti-apoptotic process. The most protective effect was observed with rhEPO when it was administrated 24 h before cisplatin treatment.

Evaluation of renal protective effects of the green-tea (EGCG) and red grape resveratrol: role of oxidative stress and inflammatory cytokines

Epigallocatechin-gallate (EGCG) and resveratrol (RSVL) are two of the most promising natural medicines. We verified their capacity to ameliorate cisplatin (CP)-induced disruption of renal glomerular filtration rate (GFR) in rats, and sought the mediatory involvement of lipid peroxidation (malondialdehyde [MDA]-level) and inflammatory cytokine (TNF-α) therein. CP (10 mg kg⁻¹), a single i.p. dose, disrupted GFR (11-fold-rise in proteinuria, 2-5-fold rise in serum creatinine/urea levels) after 7 days, and killed all animals after 10 days. Kidney-homogenates from CP-treated rats displayed higher MDA and TNF-α, but lower reduced-glutathione (GSH) levels. Rats treated with EGCG (50 mg kg⁻¹, but not 25 mg kg⁻¹) had no fatalities and showed significantly-recovered GFR; while their kidney-homogenates had markedly reduced MDA, TNF-α and enhanced GSH levels at 7 days. Conversely, RSVL or quercetin (25, 50 mg kg⁻¹) neither improved GFR nor reduced (MDA)/TNF-α levels after 7 days. Resuming treatment with 50 mg kg⁻¹ for 10 days rescued only 25% of animals (p > 0.05). Correlation studies showed a significant association between creatinine level, and each of MDA (r = 0.91), GSH (r = -0.87), and TNF-α (0.91). The study showed for the first time that EGCG, unlike RSVL, can protect against CP-induced nephrotoxicity. At the molecular level, CP triggers a high level of oxidative stress and systemic inflammation, events that were all abrogated with EGCG; better than RSVL or quercetin.

Murine hepatic aldehyde dehydrogenase 1a1 is a major contributor to oxidation of aldehydes formed by lipid peroxidation

Reactive lipid aldehydes are implicated in the pathogenesis of various oxidative stress-mediated diseases, including non-alcoholic steatohepatitis, atherosclerosis, Alzheimer's and cataract. In the present study, we sought to define which hepatic Aldh isoform plays a major role in detoxification of lipid-derived aldehydes, such as acrolein and HNE by enzyme kinetic and gene expression studies. The catalytic efficiencies for metabolism of acrolein by Aldh1a1 was comparable to that of Aldh3a1 (V(max)/K(m)=23). However, Aldh1a1 exhibits far higher affinity for acrolein (K(m)=23.2 μM) compared to Aldh3a1 (K(m)=464 μM). Aldh1a1 displays a 3-fold higher catalytic efficiency for HNE than Aldh3a1 (218 ml/min/mg vs 69 ml/min/mg). The endogenous Aldh1a1 gene was highly expressed in mouse liver and a liver-derived cell line (Hepa-1c1c7) compared to Aldh2, Aldh1b1 and Aldh3a1. Aldh1a1 mRNA levels was 34-fold and 73-fold higher than Aldh2 in mouse liver and Hepa-1c1c7 cells respectively. Aldh3a1 gene was absent in mouse liver, but moderately expressed in Hepa-1c1c7 cells compared to Aldh1a1. We demonstrated that knockdown of Aldh1a1 expression by siRNA caused Hepa-1c1c7 cells to be more sensitive to acrolein-induced cell death and resulted in increased accumulation of acrolein-protein adducts and caspase 3 activation. These results indicate that Aldh1a1 plays a major role in cellular defense against oxidative damage induced by reactive lipid aldehydes in mouse liver. We also noted that hepatic Aldh1a1 mRNA levels were significantly increased (≈3-fold) in acrolein-fed mice compared to control. In addition, hepatic cytosolic ALDH activity was induced by acrolein when 1mM NAD(+) was used as cofactor, suggesting an Aldh1a1-protective mechanism against acrolein toxicity in mice liver. Thus, mechanisms to induce Aldh1a1 gene expression may provide a useful rationale for therapeutic protection against oxidative stress-induced pathologies.

UVA-induced phenoxyl radical formation: A new cytotoxic principle in photodynamic therapy

Psoralens are regularly used in therapy in combination with ultraviolet A light irradiation (PUVA) to treat skin diseases such as psoriasis, vitiligo, and mycosis fungoides. PUVA therapy is also used within the scope of extracorporeal photopheresis to treat a variety of diseases that have a suspected involvement of pathogenic T cells, including rejection of organ transplants, graft-vs-host disease, cutaneous T cell lymphoma, and autoimmune disorders. Because psoralens are the only photosensitizers used in PUVA therapies and are considered to be responsible for a number of side effects, the identification of alternative drugs is of practical interest. Here we investigated the impact of activated Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a hydrophilic vitamin E analog lacking the phytyl tail, as an alternative photoactivatable agent with T cell cytotoxic properties. Despite the well-known antioxidative capacity of Trolox, we found that at low UVA doses and in the presence of supraphysiological concentration of nitrite, a natural constituent of human skin, this compound selectively enhances radical-mediated cytotoxicity toward T cells but not toward human skin fibroblasts, keratinocytes, or endothelial cells. The cytotoxic mechanism comprises a reaction of Trolox with photo-decomposition products of nitrite, which leads to increased Trolox phenoxyl radical formation, increased intracellular oxidative stress, and a consecutive induction of apoptosis and necrosis in fast proliferating T cells. Thus, the identified UVA/nitrite-induced phenoxyl radical formation provides an opportunity for a new cytotoxic photodynamic therapy.

Inhibition of hydrogen sulphide formation reduces cisplatin-induced renal damage

BACKGROUND

Cisplatin (CP)-induced renal damage is associated with inflammation. Hydrogen sulphide (H2S) is involved in models of inflammation. This study evaluates the effect of DL-propargylglycine (PAG), an inhibitor of endogenous H2S formation, on the renal damage induced by CP.

METHODS

The rats were injected with CP (5 mg/kg, i.p.) or PAG (5 mg/kg twice a day, i.p.) for 4 days, starting 1 h before CP injection. Control rats were injected with 0.15 M NaCl or PAG only. Blood and urine samples were collected 5 days after saline or CP injections for renal function evaluation. The kidneys were removed for tumour necrosis factor (TNF)-α quantification, histological, immunohistochemical and Western blot analysis. The cystathionine γ-lyase (CSE) activity and expression were assessed. The direct toxicity of H(2)S in renal tubular cells was evaluated by the incubation of these cells with NaHS, a donor of H2S.

RESULTS

CP-treated rats presented increases in plasma creatinine levels and in sodium and potassium fractional excretions associated with tubulointerstitial lesions in the outer medulla. Increased expression of TNF-α, macrophages, neutrophils and T lymphocytes, associated with increased H2S formation rate and CSE expression, were also observed in the outer medulla from CP-injected rats. All these alterations were reduced by treatment with PAG. A direct toxicity of NaHS for renal tubular epithelial cells was not observed.

CONCLUSIONS

Treatment with PAG reduces the renal damage induced by CP. This effect seems to be related to the H2S formation and the restriction of the inflammation in the kidneys from PAG + CP-treated rats.

Ameliorative effect of riboflavin on the cisplatin induced nephrotoxicity and hepatotoxicity under photoillumination

Cisplatin is a widely used anticancer drug. It is documented that it elicits major side effects like nephrotoxicity and hepatotoxicity due to oxidative stress forcing the patients to limit its clinical use in long term treatment. Riboflavin (vitamin B(2)) is a strong photosensitizer because it generates reactive oxygen species (ROS) upon photoillumination. We have tried to trap its photosensitizing property to ameliorate the cisplatin induced nephrotoxicity and hepatotoxicity in mice. They were treated with riboflavin and cisplatin separately as well as with their combination under photoilluminated condition. The status of major antioxidant enzymes, antioxidant proteins, functional markers, lipid peroxidation and protein oxidation was studied in liver, kidneys and serum samples of all the groups. Cisplatin treated group showed significantly compromised level of antioxidant enzymes and the proteins with higher extent of lipid and protein oxidation. Similar but less pronounced pattern was observed in the riboflavin treated group. The groups treated with the combination of cisplatin and riboflavin showed all the parameters tended towards normal levels in a dose dependent manner. Hence, it can be hypothesized that riboflavin shows ameliorative effect on the cisplatin induced nephrotoxicity and hepatotoxicity under the mentioned treatment conditions.

Overexpression of aldehyde dehydrogenase 1A1 reduces oxidation-induced toxicity in SH-SY5Y neuroblastoma cells

Oxidative stress leading to lipid peroxidation is a problem in neurodegenerative diseases, because the brain is rich in polyunsaturated fatty acids and low in endogenous antioxidants. One of the most toxic byproducts of lipid peroxidation, 4-hydroxynonenal (HNE), is implicated in oxidative stress-induced damage in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). In this study, the human neuroblastoma cell line SH-SY5Y was used to test the protective effects of increasing the detoxification of HNE by overexpressing the HNE-detoxifying enzyme aldehyde dehydrogenase 1A1 (ALDH1). Overexpression of ALDH1 in the SH-SY5Y cells acts to reduce production of protein-HNE adducts and activation of caspase-3. Our data suggest that detoxification of HNE could be therapeutic in preventing some of the toxic disruptions of the brain's redox systems found in many neurodegenerative diseases.

Trolox prevents osteoclastogenesis by suppressing RANKL expression and signaling

Excessive receptor activator of NF-kappaB ligand (RANKL) signaling causes enhanced osteoclast formation and bone resorption. Thus, down-regulation of RANKL expression or its downstream signals may be a therapeutic approach to the treatment of pathological bone loss. In this study, we investigated the effects of Trolox, a water-soluble vitamin E analogue, on osteoclastogenesis and RANKL signaling. Trolox potently inhibited interleukin-1-induced osteoclast formation in bone marrow cell-osteoblast coculture by abrogating RANKL induction in osteoblasts. This RANKL reduction was attributed to the reduced production of prostaglandin E(2) via a down-regulation of cyclooxygenase-2 activity. We also found that Trolox inhibited osteoclast formation from bone marrow macrophages induced by macrophage colony-stimulating factor plus RANKL in a reversible manner. Trolox was effective only when present during the early stage of culture, which implies that it targets early osteoclast precursors. Pretreatment with Trolox did not affect RANKL-induced early signaling pathways, including MAPKs, NF-kappaB, and Akt. We found that Trolox down-regulated the induction by RANKL of c-Fos protein by suppressing its translation. Ectopic overexpression of c-Fos rescued the inhibition of osteoclastogenesis by Trolox in bone marrow macrophages. Trolox also suppressed interleukin-1-induced osteoclast formation and bone loss in mouse calvarial bone. Taken together, our findings indicate that Trolox prevents osteoclast formation and bone loss by inhibiting both RANKL induction in osteoblasts and c-Fos expression in osteoclast precursors.

PERP, a p53 proapoptotic target, mediates apoptotic cell death in renal ischemia

The p53 tumor suppressor gene plays a crucial role in mediating apoptotic cell death in renal ischemia-reperfusion injury (IRI). To further elucidate the p53-dependent pathway, we investigated the role of the p53 apoptosis effector related to PMP-22 (PERP), an apoptosis-associated p53 transcriptional target. PERP mRNA and protein are highly induced in the outer medullary proximal tubular cells (PTC) of ischemic kidneys postreperfusion at 3, 12, and 24 h in a p53-dependent manner. In PTC, overexpression of PERP augmented the rate of apoptosis following hypoxia by inducing mitochondrial permeability and subsequent release of cytochrome c, apoptosis-inducing factor (AIF), and caspase 9 activation. In addition, silencing of the PERP gene with short hairpin RNA prevented apoptosis in hypoxia-mediated injury by precluding mitochondrial dysfunction and consequent cytochrome c and AIF translocation. These data suggest that PERP is a key effector of p53-mediated apoptotic pathways and is a potential therapeutic target for renal IRI.

Role of oxidative and nitrosative stress in cisplatin-induced nephrotoxicity

cis-Diamminedichloroplatinum (II) (cisplatin) is an important chemotherapeutic agent useful in the treatment of several cancers; however, it has several side effects such as nephrotoxicity. The role of the oxidative and nitrosative stress in cisplatin-induced nephrotoxicity is additionally supported by the protective effect of several free radical scavengers and antioxidants. Furthermore, in in vitro experiments, antioxidants or reactive oxygen species (ROS) scavengers have a cytoprotective effect on cells exposed to cisplatin. Recently, the participation of nitrosative stress has been more explored in cisplatin-induced renal damage. The use of a water-soluble Fe(III) porphyrin complex able to metabolize peroxynitrite (ONOO(-)) has demonstrated that this anion contributes to both in vivo and in vitro cisplatin-induced toxicity. ONOO(-) is produced when nitric oxide (NO*) reacts with superoxide anion (O(2)(*-)); currently, there are evidences suggesting alterations in NO* production after cisplatin treatment and the evidence appear to NO* has a toxic effect. This article goes through current evidence of the mechanism by more than a few compounds have beneficial effects on cisplatin-induced nephrotoxicity, contribute to understanding the role of oxidative and nitrosative stress and suggest several points as part of the mechanism of cisplatin toxicity.

Regulation and pathological role of p53 in cisplatin nephrotoxicity

Cisplatin is one of the most potent chemotherapy drugs widely used for cancer treatment. However, its use is limited by side effects in normal tissues, particularly the kidneys. Recent studies, using both in vitro and in vivo experimental models, have suggested a critical role for p53 in cisplatin nephrotoxicity. The signaling pathways upstream and downstream of p53 are being investigated and related to renal cell injury and death. Along with the mechanistic studies, renoprotective approaches targeting p53 have been suggested. Further research may integrate p53 signaling with other nephrotoxic signaling pathways, providing a comprehensive understanding of cisplatin nephrotoxicity and leading to the development of effective renoprotective strategies during cancer therapy.

Renal cell apoptosis induced by nephrotoxic drugs: cellular and molecular mechanisms and potential approaches to modulation

Apoptosis plays a central role not only in the physiological processes of kidney growth and remodeling, but also in various human renal diseases and drug-induced nephrotoxicity. We present in a synthetic fashion the main molecular and cellular pathways leading to drug-induced apoptosis in kidney and the mechanisms regulating it. We illustrate them using three main nephrotoxic drugs (cisplatin, gentamicin, and cyclosporine A). We discuss the main regulators and effectors that have emerged as key targets for the design of therapeutic strategies. Novel approaches using gene therapy, antisense strategies, recombinant proteins, or compounds obtained from both classical organic and combinatorial chemistry are examined. Finally, key issues that need to be addressed for the success of apoptosis-based therapies are underlined.

Vitamin C attenuates cisplatin-induced alterations in renal brush border membrane enzymes and phosphate transport

Cisplatin is a widely used antineoplastic agent that exhibits dose limiting nephrotoxicity. We have previously shown that the administration of cisplatin results in decrease in the activities of renal brush border membrane (BBM) enzymes and transport of inorganic phosphate (Pi) across BBM vesicles. In the present study we have investigated the effect of pre-treatment with vitamin C (ascorbic acid) on cisplatin-induced nephrotoxicity and changes in BBM enzymes and Pi transport. Administration of a single dose of cisplatin (6 mg/kg body weight) caused nephrotoxicity in rats that manifested biochemically as an elevation of serum urea nitrogen and creatinine levels. Treatment of rats with a single dose of vitamin C, six hours prior to administration of cisplatin, protected the kidney from the damaging effect of cisplatin. Vitamin C pre-treatment significantly decreased the urea nitrogen and creatinine levels. It attenuated the cisplatin-induced reduction in the activities of BBM and anti-oxidant enzymes and also Pi transport. These results suggest that vitamin C is an effective chemoprotectant against cisplatin-induced acute renal failure and dysfunction of the renal BBM in rats.

Effect of cisplatin on brush border membrane enzymes and anti-oxidant system of rat intestine

Cisplatin (CP) is a widely used antineoplastic agent which exhibits gastrointestinal toxicity. The present work was done to study the effect of administration of CP on brush border membrane (BBM) enzymes and anti-oxidant system of rat intestine. Male Wistar rats were given a single intraperitoneal dose of CP (6 mg/kg body weight) and then sacrificed 1, 3, 5 and 7 days after this treatment. Control animals were given saline only. The administration of CP led to significant decline in the specific activities of BBM enzymes both in the mucosal homogenates and isolated membrane vesicles. Kinetic studies showed that the V(max) of the enzymes was decreased in BBM vesicles from CP treated rats while the K(m) remained unchanged. The activities of catalase, Cu-Zn superoxide dismutase, glucose 6-phosphate dehydrogenase and glutathione reductase decreased while the activities of glutathione S-transferase and thioredoxin reductase increased in CP treated animals compared to the control group. Lipid peroxidation and total sulfhydryl groups were also altered upon CP treatment indicating the generation of oxidative stress. The maximum changes in all the parameters studied above were 3 days after administration of CP and then recovery took place on days 5 and 7. Thus, the administration of CP leads to significant alterations in the activities of BBM enzymes and the anti-oxidant status of rat intestine.

In vivo and in vitro antitumor effect of a unique nutrient mixture on lung cancer cell line A-549

The high incidence of lung cancer and ineffective toxic action of current mono and doublet chemotherapy approaches result in poor patient survival. Further, matrix metalloproteinases (MMPs) are implicated in neoplastic invasion and metastasis. Based on this, the authors investigated the effect of a dietary micronutrient mixture (NM) containing lysine, proline, arginine, ascorbic acid, and green tea extract on the tumor growth of human lung carcinoma cell A-549 xenografts in athymic nude mice. Additionally, the authors tested the in vitro antitumor effect of NM on lung carcinoma A-549 cells by measuring cell proliferation by MTT assay, MMP-2 and -9 secretion by gelatinase zymography, and cell invasion through Matrigel. Nutrient supplementation strongly suppressed the growth of tumors without adverse effects in nude mice; tumor weight was reduced by 44% (P = .0001) and tumor burden was reduced by 47% (P < .0001) with supplementation. Zymography demonstrated in vitro secretion of MMP-2 by uninduced human lung carcinoma cells and both MMP-2 and -9 by phorbol 12-mysristate 13-acetate (PMA) (200 ng/mL)-treated cells. NM inhibited the secretion of both MMPs in a dose-dependent fashion, with virtual total inhibition at 500 microg/mL concentration. The invasion of human lung carcinoma cells through Matrigel was significantly reduced at 100 microg/mL (64%) and totally inhibited at 500 microg/mL concentration of NM (P = .01). Suppression of lung tumor growth in nude mice and inhibition of MMP secretion and Matrigel invasion suggest NM may act as an anticancer agent and as such warrants further investigation.

Parthenolide reduces cisplatin-induced renal damage

Inflammatory events contribute to cisplatin-induced renal damage. Cisplatin promotes increased production of reactive oxygen species, which can activate nuclear factor-kappaB (NF-kappaB) that lead to increased expression of proinflammatory mediators which could intensify the cytotoxic effects of cisplatin. In this study, we evaluated the effect of parthenolide, a selective inhibitor of NF-kappaB, on renal damage caused by cisplatin use. A total of 94 male Wistar rats were divided into six groups: Group A (18 rats) were treated with saline; Group B (12 rats) received dimethylsulfoxide plus saline (the solvent for parthenolide); Group C (12 rats) received parthenolide (3mg/kg) plus saline; Group D (20 rats) received cisplatin (5mg/kg, i.p.); Group E (12 rats) received dimethylsulfoxide plus cisplatin (5mg/kg, i.p.); and Group F (21 rats) received parthenolide (3mg/kg) plus cisplatin (5mg/kg, i.p.). Dimethylsulfoxide or parthenolide were administered at 24h and 1h prior to cisplatin injection, and again at 24h and 48h after. At 2, 3 and 5 days after saline or cisplatin injection, blood and urine samples were collected for measurement of creatinine, sodium and potassium and the kidneys removed for histological, morphometric, electrophoretic mobility shift assay (EMSA), apoptosis and immunohistochemical studies. Cisplatin-treated rats presented higher plasma creatinine, as well as greater immunostaining for ED1 (macrophages/monocytes) and NF-kappaB in the renal cortices and outer medullae. The increase of NF-kappaB activation was confirmed by EMSA. Cisplatin-injected rats also presented higher urinary levels of lipid peroxidation and acute tubular necrosis. All of these alterations were reduced by treatment with parthenolide. This effect seems to be related, at least in part, to the restriction of renal inflammatory process observed in parthenolide+cisplatin treated rats.