Comparative in vivo evaluations of curcumin and its analog difluorinated curcumin against cisplatin-induced nephrotoxicity

Targeting mTOR with curcumin: therapeutic implications for complex diseases

The mammalian target of rapamycin (mTOR) is a crucial enzyme in regulating multiple signaling pathways in the body, including autophagy, proliferation and apoptosis. Disruption of these mTOR signaling pathways can lead to an array of abnormalities and trigger disease processes, examples being neurodegenerative conditions, cancer, obesity and diabetes. Under conditions of oxidative stress, mTOR can regulate apoptosis and autophagy, with tissue repair being favored under such circumstances. Moreover, the correlation between mTOR and other signaling pathways could play a pivotal role in the pathophysiology of numerous disorders. mTOR has a tight connection with NF-κB, Akt, PI3K, MAPK, GSK-3β, Nrf2/HO-1, JAK/STAT, CREB/BDNF, and ERK1/2 pathways, which together could play significant roles in the regulation of inflammation, apoptosis, cell survival, and oxidative stress in different body organs. Research suggests that inhibiting mTOR could be beneficial in treating metabolic, neurological and cardiovascular conditions, as well as potentially extending life expectancy. Therefore, identifying new chemicals and agents that can modulate the mTOR signaling pathway holds promise for treating and preventing these disorders. Curcumin is one such agent that has demonstrated regulatory effects on the mTOR pathway, making it an exciting alternative for reducing complications associated with complex diseases by targeting mTOR. This review aims to examine the potential of curcumin in modulating the mTOR signaling pathway and its therapeutic implications.

Is oral nano-curcumin formulation a safe and effective measure for preventing cisplatin-induced nephrotoxicity in cancer patients?

Nephrotoxicity is one of the most important complications in cancer patients under treatment with cisplatin-containing regimens. Curcumin, as the most important active component of Curcuma longa, is an antioxidant and anti-inflammatory compound. In this clinical trial, we assessed the preventive effect of nano-curcumin oral formulation against cisplatin-induced nephrotoxicity in cancer patients. In this triple-blind clinical trial 30 cancer patients on cisplatin were randomly included in the treatment group, receiving nano-curcumin 40 mg capsules ( n  = 15) or the placebo group ( n  = 15) twice a day during four chemotherapy courses. Kidney function was measured at the beginning of the study and then at the end of each course of chemotherapy. There was no significant difference in acute kidney injury occurrence rate and creatinine and blood urine nitrogen serum levels between the treatment and placebo groups at the end of each chemotherapy course ( P value >0.05). Just at the end of the first course, the difference was close to significant ( P  = 0.055). We also found no difference in mortality and recurrence rate in an average 30-month follow-up. Nano-curcumin in the prescribed dose and duration was not effective in preventing cisplatin-induced nephrotoxicity in cancer patients in comparison with the placebo. Further studies with larger sample size using different doses and duration of nano-curcumin are recommended.

Polymorphic renal transporters and cisplatin's toxicity in urinary bladder cancer patients: current perspectives and future directions

Urinary bladder cancer (UBC) holds a potentially profound social burden and affects over 573,278 new cases annually. The disease's primary risk factors include occupational tobacco smoke exposure and inherited genetic susceptibility. Over the past 30 years, a number of treatment modalities have emerged, including cisplatin, a platinum molecule that has demonstrated effectiveness against UBC. Nevertheless, it has severe dose-limiting side effects, such as nephrotoxicity, among others. Since intracellular accumulation of platinum anticancer drugs is necessary for cytotoxicity, decreased uptake or enhanced efflux are the root causes of platinum resistance and response failure. Evidence suggests that genetic variations in any transporter involved in the entry or efflux of platinum drugs alter their kinetics and, to a significant extent, determine patients' responses to them. This review aims to consolidate and describe the major transporters and their polymorphic variants in relation to cisplatin-induced toxicities and resistance in UBC patients. We concluded that the efflux transporters ABCB1, ABCC2, SLC25A21, ATP7A, and the uptake transporter OCT2, as well as the organic anion uptake transporters OAT1 and OAT2, are linked to cisplatin accumulation, toxicity, and resistance in urinary bladder cancer patients. While suppressing the CTR1 gene's expression reduced cisplatin-induced nephrotoxicity and ototoxicity, inhibiting the expression of the MATE1 and MATE2-K genes has been shown to increase cisplatin's nephrotoxicity and resistance. The roles of ABCC5, ABCA8, ABCC10, ABCB10, ABCG1, ATP7B, ABCG2, and mitochondrial SLC25A10 in platinum-receiving urinary bladder cancer patients should be the subject of further investigation.

A synchronized dual drug delivery molecule targeting cancer stem cells in tumor heterogeneity and metastasis

Cancer stem-like cells (CSCs) represent a key barrier to successful therapy for triple-negative breast cancer (TNBC). CSCs promote the emergence of chemoresistance, triggering relapse and resulting in a poor prognosis. We herein present CDF-TM, a new small molecule-based binary prodrug conjugated with SN-38 and 3,4-difluorobenzylidene curcumin (CDF) that is specifically activated in hypoxic conditions. CDF-TM treatment significantly induced apoptosis in TNBC-derived 3D spheroids, accompanied with caspase-3 activation as well as the attenuation of tumor stemness with evidence of reduction in aldehyde dehydrogenase 1 (ALDH1) activity and the CD44^high/CD24^low phenotype. An in vivo orthotopic allograft model was used to investigate its effects on tumor growth and metastasis. The dissemination of CSCs from primary allografts was impaired by CDF-TM, along with inhibition of tumor growth via eradication of CSCs and downregulation of multidrug resistance 1 (MDR1). This new small molecule-based binary prodrug offers a novel therapeutic option for metastatic TNBC.

Polyphenols and Their Metabolites in Renal Diseases: An Overview

Kidney diseases constitute a worldwide public health problem, contributing to morbidity and mortality. The present study aimed to provide an overview of the published data regarding the potential beneficial effects of polyphenols on major kidney diseases, namely acute kidney injury, chronic kidney disease, diabetic nephropathy, renal cancer, and drug-induced nephrotoxicity. This study consists of a bibliographical review including in vitro and in vivo studies dealing with the effects of individual compounds. An analysis of the polyphenol metabolome in human urine was also conducted to estimate those compounds that are most likely to be responsible for the kidney protective effects of polyphenols. The biological effects of polyphenols can be highly attributed to the modulation of specific signaling cascades including those involved in oxidative stress responses, anti-inflammation processes, and apoptosis. There is increasing evidence that polyphenols afford great potential in renal disease protection. However, this evidence (especially when in vitro studies are involved) should be considered with caution before its clinical translation, particularly due to the unfavorable pharmacokinetics and extensive metabolization that polyphenols undergo in the human body. Future research should consider polyphenols and their metabolites that indeed reach kidney tissues.

Site-Specific Binding of Anticancer Drugs to Human Serum Albumin

The interaction of drugs with proteins plays a very important role in the distribution of the drug. Human serum albumin (HSA) is the most abundant protein in the human body and showing great binding characteristics has gained a lot of importance pharmaceutically. It plays an essential role in the pharmacokinetics of a number of drugs and hence several reports are available on the interaction of drugs with HSA. It can bind to cancer drugs and thus it is crucial to look at the binding characteristics of these drugs with HSA. Herein we summarize the binding properties of some anti-cancer drugs by specifically looking into the binding site with HSA. The number of drugs binding at Sudlow's site I situated in subdomain II A is more than the drugs binding at Sudlow's site II.

Next-Generation Ultrasol Curcumin Boosts Muscle Endurance and Reduces Muscle Damage in Treadmill-Exhausted Rats

Curcumin positively affects performance during exercise and subsequent recovery. However, curcumin has limited bioavailability unless consumed in larger doses. In the current study, we examined the impact of a new formulation of curcumin, Next-Generation Ultrasol Curcumin (NGUC), which is relatively more bioavailable than natural curcumin on exhaustion time, grip strength, muscle damage parameters, and serum and muscle proteins. A total of 28 rats were randomly grouped as control (C, non-supplemented), exercise (E, non-supplemented), E+NGUC100 (supplemented with 100 mg/kg BW NGUC), and E+NGUC200 (supplemented with 200 mg/kg NGUC). Grip strength and exhaustion time were increased with NGUC supplementation (p < 0.0001). Creatine kinase (CK), lactate dehydrogenase (LDH), lactic acid (LA), myoglobin, malondialdehyde (MDA) concentrations were reduced in serum, and muscle tissue in NGUC supplemented groups (p < 0.05). In contrast, NGUC supplementation elevated the antioxidant enzyme levels compared to the non-supplemented exercise group (p < 0.01). Additionally, inflammatory cytokines were inhibited with NGUC administration (p < 0.05). NGUC decreased PGC-1α, p-4E-BP1, p-mTOR, MAFbx, and MuRF1 proteins in muscle tissue (p < 0.05). These results indicate that NGUC boosts exercise performance while reducing muscle damage by targeting antioxidant, anti-inflammatory, and muscle mass regulatory pathways.

Curcumin and its derivatives in cancer therapy: Potentiating antitumor activity of cisplatin and reducing side effects

Curcumin is a phytochemical isolated from Curcuma longa with potent tumor-suppressor activity, which has shown significant efficacy in pre-clinical and clinical studies. Curcumin stimulates cell death, triggers cycle arrest, and suppresses oncogenic pathways, thereby suppressing cancer progression. Cisplatin (CP) stimulates DNA damage and apoptosis in cancer chemotherapy. However, CP has adverse effects on several organs of the body, and drug resistance is frequently observed. The purpose of the present review is to show the function of curcumin in decreasing CP's adverse impacts and improving its antitumor activity. Curcumin administration reduces ROS levels to prevent apoptosis in normal cells. Furthermore, curcumin can inhibit inflammation via down-regulation of NF-κB to maintain the normal function of organs. Curcumin and its nanoformulations can reduce the hepatoxicity, neurotoxicity, renal toxicity, ototoxicity, and cardiotoxicity caused by CP. Notably, curcumin potentiates CP cytotoxicity via mediating cell death and cycle arrest. Besides, curcumin suppresses the STAT3 and NF-ĸB as tumor-promoting pathways, to enhance CP sensitivity and prevent drug resistance. The targeted delivery of curcumin and CP to tumor cells can be mediated nanostructures. In addition, curcumin derivatives are also able to reduce CP-mediated side effects, and increase CP cytotoxicity against various cancer types.

A Small Molecule Strategy for Targeting Cancer Stem Cells in Hypoxic Microenvironments and Preventing Tumorigenesis

Breast cancer consists of heterogenic subpopulations, which determine the prognosis and response to chemotherapy. Among these subpopulations, a very limited number of cancer cells are particularly problematic. These cells, known as breast cancer stem cells (BCSCs), are thought responsible for metastasis and recurrence. They are thus major contributor to the unfavorable outcomes seen for many breast cancer patients. BCSCs are more prevalent in the hypoxic niche. This is an oxygen-deprived environment that is considered crucial to their proliferation, stemness, and self-renewal but also one that makes BCSCs highly refractory to traditional chemotherapeutic regimens. Here we report a small molecule construct, AzCDF, that allows the therapeutic targeting of BCSCs and which is effective in normally refractory hypoxic tumor environments. A related system, AzNap, has been developed that permits CSC imaging. Several design elements are incorporated into AzCDF, including the CAIX inhibitor acetazolamide (Az) to promote localization in MDA-MB-231 CSCs, a dimethylnitrothiophene subunit as a hypoxia trigger, and a 3,4-difluorobenzylidene curcumin (CDF) as a readily released therapeutic payload. This allows AzCDF to serve as a hypoxia-liable molecular platform that targets BCSCs selectively which decreases CSC migration, retards tumor growth, and lowers tumorigenesis rates as evidenced by a combination of in vitro and in vivo studies. To the best of our knowledge, this is the first time a CSC-targeting small molecule has been shown to prevent tumorigenesis in an animal model.

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.

Antioxidant effect of ascorbic acid against cisplatin-induced nephrotoxicity and P-glycoprotein expression in rats

Cisplatin (CDDP) is a highly potent anticancer drug that is widely used in the treatment of several cancers. CDDP-induced nephrotoxicity (CIN) is one of the most significant adverse effects, and oxidative stress is thought to be one of the mechanisms underlying CIN. Although there are some studies available on the variability in transporter expression in the kidney after a single CDDP dose, none have reported the change in renal transporter expression after multiple CDDP dose administrations. P-glycoprotein (P-gp), a transporter, is reported to be induced by oxidative stress. Ascorbic acid is a vitamin with antioxidant potential and therefore, may regulate the expression of P-gp transporter and affect CIN. In the present study, our aim was to assess the variability in expression of several renal transporters after multiple CDDP dose administrations and the antioxidant effect of ascorbic acid against transporter expression and CIN. Multiple doses of CDDP affected markers of kidney injury and antioxidants in the kidneys. Also, the expression of P-gp, breast cancer resistance protein, and multidrug resistance-associated protein 4 was upregulated by CDDP. Using a normal kidney cell line, we demonstrated that ascorbic acid attenuated CDDP-induced cytotoxicity due to its high superoxide scavenging ability. CDDP and ascorbic acid were injected into rats once a week for three weeks, and it was observed that co-administration of ascorbic acid attenuated CIN and regulated antioxidant marker. In addition, ascorbic acid reduced P-gp expression, which was upregulated by CDDP. In conclusion, ascorbic acid may attenuate CIN and reverse P-gp-mediated changes in drug pharmacokinetics.

Cisplatin chemotherapy and renal function

Cisplatin has been a mainstay of cancer chemotherapy since the 1970s. Despite its broad anticancer potential, its clinical use has regularly been constrained by kidney toxicities. This review details those biochemical pathways and metabolic conversions that underlie the kidney toxicities. A wide range of redox events contribute to the eventual physiological consequences of drug activities.

AMPK/mTOR Signaling in Autophagy Regulation During Cisplatin-Induced Acute Kidney Injury

Autophagy is a conserved, multistep pathway that degrades and recycles dysfunctional organelles and macromolecules to maintain cellular homeostasis. Mammalian target of rapamycin (mTOR) and adenosine-monophosphate activated-protein kinase (AMPK) are major negative and positive regulators of autophagy, respectively. In cisplatin-induced acute kidney injury (AKI) or nephrotoxicity, autophagy is rapidly induced in renal tubular epithelial cells and acts as a cytoprotective mechanism for cell survival. Both mTOR and AMPK have been implicated in the regulation of autophagy in cisplatin-induced AKI. Targeting mTOR and/or AMPK may offer effective strategies for kidney protection during cisplatin-mediated chemotherapy.

A meta-analysis of preclinical studies using antioxidants for the prevention of cisplatin nephrotoxicity: implications for clinical application

Cisplatin is an effective chemotherapeutic drug whose clinical use and efficacy are limited by its nephrotoxicity, which affects mainly the renal tubules and vasculature. It accumulates in proximal and distal epithelial tubule cells and causes oxidative stress-mediated cell death and malfunction. Consequently, many antioxidants have been tested for their capacity to prevent cisplatin nephrotoxicity. In this study, we made a systematic review of the literature and meta-analyzed 152 articles, which tested the nephroprotective effect of isolated compounds or mixtures of natural origin on cisplatin nephrotoxicity in preclinical models. This meta-analysis identified the most effective candidates and examined the efficacy obtained by antioxidants administered by the oral and intraperitoneal routes. By comparing with a recent, similar meta-analysis performed on clinical studies, this article identifies a disconnection between preclinical and clinical research, and contextualizes, discusses, and integrates the existing preclinical information toward the optimized selection of candidates to be further explored (clinical level). Despite proved efficacy, this article discusses the barriers limiting the clinical development of natural mixtures, such as those in extracts from Calendula officinalis flowers and Heliotropium eichwaldii roots. On the contrary, isolated compounds are more straightforward candidates, among which arjunolic acid and quercetin stand out in this meta-analysis.

Comparison of the nephroprotective effects of non-steroidal anti-inflammatory drugs on cisplatin-induced nephrotoxicity in vitro and in vivo

Cisplatin (CDDP) is an anticancer drug, often used in the treatment of several types of cancers. CDDP-induced nephrotoxicity (CIN) is one of the most severe adverse events associated with the use of CDDP. It has been suggested that the co-administration of non-steroidal anti-inflammatory drugs (NSAIDs) is a risk factor for CIN. However, the specific NSAIDs that affect CIN and the precise mechanisms underlying this interaction remain unclear. Hence, we aimed to evaluate the effect of NSAIDs on CDDP-induced cytotoxicity in vitro and confirmed the results in vivo. Using the epithelioid clone of the normal rat kidney cells (NRK-52E cells), we assessed the effects of 17 NSAIDs on CDDP-induced cytotoxicity all at once using the MTT assay. Furthermore, we evaluated two NSAIDs, which significantly attenuated or enhanced CDDP-induced cytotoxicity, in vivo. Wistar rats were treated with CDDP (5 mg/kg, i.p., day 1) and NSAIDs (p.o., day 1-4), and the kidneys were excised on day 5. Our results demonstrated that several NSAIDs attenuated, while others enhanced CDDP-induced cytotoxicity. Celecoxib significantly attenuated and flurbiprofen markedly enhanced cell dysfunction by CDDP. These results were reproduced in vivo as celecoxib decreased and flurbiprofen increased the expression of kidney injury molecule 1 (Kim-1) mRNA, a sensitive kidney injury marker, compared to the CDDP group. Moreover, celecoxib increased the antioxidant and autophagy markers quantified by qPCR in vitro and prevented a decrease in body weight induced by CDDP in vivo. In conclusion, we revealed that celecoxib significantly attenuated CIN in vitro and in vivo.

Spirogyra neglecta Aqueous Extract Attenuates LPS-Induced Renal Inflammation

Spirogyra neglecta (SN), commonly named "Tao" in Thai, is a genus of filamentous green macroalgae. SN contains polyphenols such as isoquercetin, catechin, hydroquinone and kaempferol. These constituents exhibit beneficial effects including anti-oxidant, anti-gastric ulcer, anti-hyperglycaemia and anti-hyperlipidaemia in both in vitro and in vivo models. Whether SN extract (SNE) has an anti-inflammatory effect in vivo remains unclear. This study examined the effect of SNE on renal function and renal organic transport in lipopolysaccharide (LPS)-induced renal inflammation in rats. Rats were randomised and divided into normal saline (NS), NS supplemented with 1000 mg/kg body weight (BW) of SNE (NS + SNE), intraperitoneally injected with 12 mg/kg BW of LPS and LPS treated with 1000 mg/kg BW of SNE (LPS + SNE). Biochemical parameters in serum and urine, lipid peroxidation concentration, kidney function and renal organic anion and cation transports were determined. LPS-injected rats developed renal injury and inflammation by increasing urine microalbumin, total malondialdehyde (MDA) and inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-1β protein expression, respectively. In addition, uptake of renal organic anion, [³H]-oestrone sulphate (ES), was reduced in LPS-injected rats together with increased expression of organic anion transporter 3 (Oat3). However, the renal injury and inflammation, as well as impaired Oat3 function and protein expression, were restored in LPS + SNE rats. Accordingly, SNE could be developed as nutraceutical product to prevent inflammation-induced nephrotoxicity.

Renoprotective Effects of a New Free Radical Scavenger, XH-003, against Cisplatin-Induced Nephrotoxicity

Acute renal injury has an incidence of 25%–30% in patients with tumors who are treated with cisplatin and in patients for whom no specific drugs are available for treatment. Amifostine is the only FDA-approved chemoprotective drug; however, its clinical application is limited because of side effects. The small-molecule antioxidant XH-003, an acute radiation syndrome- (ARS-) protective drug independently developed in our laboratory, with 100% intellectual property rights, overcomes the side effects of amifostine but retains its high efficacy. In this study, XH-003 showed a chemoprotective effect similar to that of amifostine. A mechanistic study showed that XH-003 could significantly reduce cisplatin-induced increases in serum creatinine and urea nitrogen, increase the activity of antioxidant enzymes (SOD, CAT, and GSH-Px), reduce oxidative stress and tissue inflammation, and alleviate renal tissue damage by blocking the activity of the mitochondrial apoptosis pathway. Most importantly, XH-003 could reduce the accumulation of cisplatin in renal tissue by regulating the expression of proteins involved in cisplatin uptake and excretion, such as organic cation transporter 2 and MRP2. Moreover, in an in vivo xenotransplantation model, XH-003 did not interfere with the antitumor effect of cisplatin. These data provide strong evidence that the ARS-protective agent has a great potential for protecting against chemotherapy-induced toxicity. Thus, XH-003 can be considered in antitumor therapy.

Piceatannol protects against cisplatin nephrotoxicity via activation of Nrf2/HO-1 pathway and hindering NF-κB inflammatory cascade

This study investigates the molecular mechanisms of the nephroprotective effect of piceatannol (PIC) against cisplatin-induced nephrotoxicity in rats. PIC (10 mg/kg i.p.) was given for 7 days, starting 2 days before cisplatin single injection (7 mg/kg i.p.). Serum creatinine, blood urea nitrogen (BUN), kidney injury molecule 1, and neutrophil gelatinase-associated lipocalin were used as nephrotoxicity markers. Oxidative stress, inflammatory, and apoptotic markers were determined. In addition, the role of PIC in Nrf2 activation and its subsequent induction of antioxidant enzymes, as well as its potential cross talk with nuclear factor kappa-B, were addressed. PIC reversed cisplatin-induced elevation of nephrotoxicity markers and restored the normal kidney ultrastructure. PIC attenuated cisplatin-induced reduction in Nrf2 expression and the relative mRNA level of antioxidant enzymes: hemeoxygenase-1, cysteine ligase catalytic, and modifier subunits, as well as superoxide dismutase and glutathione-S-transferase activities. Cisplatin pro-inflammatory response was reduced by PIC treatment as evidenced by the suppression of nuclear factor kappa-B activation and the subsequent decreased tissue levels of interleukin-1β, tumor necrosis factor-α, cyclooxygenase-2, and inducible nitric oxide synthase. PIC suppressed cisplatin-induced apoptosis by decreasing p53 and cytochrome C expression and caspase-3 activity. Therefore, PIC may protect against cisplatin-induced nephrotoxicity by modulating Nrf2/HO-1 signaling and hindering the inflammatory and apoptotic pathways.

Protective Role of Natural Products in Cisplatin-Induced Nephrotoxicity

Cisplatin is a widely used antineoplastic agent for the treatment of metastatic tumors, advanced bladder cancer and many other solid tumors. However, at higher doses, toxicities such as nephrotoxicity may appear. Cisplatin leads to DNA damage and subsequently renal cell death. Besides that, oxidative stress is also implicated as one of the main causes of nephrotoxicity. Several studies showed that numerous natural products: ginseng, curcumin, licorice, honey and pomegranate were able to reduce the oxidative stress by restoring the levels of antioxidant enzymes and also at the same time act as an anti-inflammatory agent. Furthermore, pre-treatment with vitamin supplementation, such as vitamin C, E and riboflavin markedly decreased serum urea and increased the levels of antioxidant enzymes in the kidney even after cisplatin induction in cancer patients. These natural products possess potent antioxidant and anti-inflammatory medicinal properties, and they can be safely used as a supplementary regime or combination therapy against cisplatin-induced nephrotoxicity. The present review focused on the protective role of a few natural products which is widely used in folk medicines in cisplatin-induced nephrotoxicity.

Efficacy of curcumin on prevention of drug-induced nephrotoxicity: A review of animal studies

Drug-induced nephrotoxicity is a frequent serious adverse effect, contributing to morbidity and increased healthcare utilization. Prevention or reversal is key. Curcumin has useful biological features that include antioxidant, anti-inflammatory, and anticancer properties. This review covers aspects of curcumin in relation to prevention of drug-induced nephrotoxicity: dosage and schedule, effect on kidney biomarkers and histological changes, and mechanisms of curcumin's protective effects. Despite success in some animal models, human studies and clinical administration of curcumin for nephroprotection remains limited due to difficulty in achieving therapeutic levels following oral administration and in determining the optimal dosing schedule. Lack of sufficient evidence from animal studies, coupled with low systemic bioavailability, continues to limit the utilization of curcumin in addressing and controlling drug-induced nephrotoxicity. Therefore, human studies are required to fully assess and validate the therapeutic potential of curcumin.

Recent advances of analogues of curcumin for treatment of cancer

Curcumin (CU), an edible natural pigment from Curcuma Longa, has demonstrated extensive anti-tumor effect in vivo and in vitro. With the property of reversing drug resistance and low toxicity, CU has been considered to develop a new adjuvant chemotherapy protocol of cancer. However, the poor stability, solubility, in vivo bioavailability and weak activity of CU greatly limit its clinical application. Therefore, CU analogues have been extensively studied. Starting from the study of natural CU analogues, multiple approaches are being sought to obtain more stable, soluble and effective analogues of CU. This review focuses on the progress of these approaches to more potent CU analogues.

Demethoxycurcumin sensitizes the response of non-small cell lung cancer to cisplatin through downregulation of TP and ERCC1-related pathways

BACKGROUND

Excision repair cross-complementary 1 (ERCC1) overexpression in lung cancer cells is strongly correlated with its resistance to platinum-based chemotherapy. Overexpression of thymidine phosphorylase (TP) reverts platinum-induced cancer cell death.

PURPOSE

Curcumin has been reported to enhance antitumor properties through the suppression of TP and ERCC1 in non-small cell lung carcinoma cells (NSCLC). Nevertheless, whether two other curcuminoids, demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC) from Curcuma longa demonstrate antitumor activity like that of curcumin remain unknown.

METHODS

MTT assay was conducted to determine the cell cytotoxicity. Western blotting was used to determine the protein expressions. Docking is the virtual screening of a database of compounds and predicting the strongest binders based on various scoring functions. BIOVIA Discovery Studio 4.5 (D.S. 4.5) were used for docking.

RESULTS

Firstly, when compared with curcumin and BDMC, DMC exhibited the most potent cytotoxic effect on NSCLC, most importantly, MRC-5, a lung fetal fibroblast, was insensitive to DMC (under 30 µM). Secondly, DMC alone significantly inhibited on-target cisplatin (CDDP) resistance protein, ERCC1, via PI3K-Akt-snail pathways, and TP protein expression in A549 cells. Thirdly, DMC treatment markedly increased post-target CDDP resistance pathway including Bax and cytochrome c. DMC significantly decreased Bcl-2 protein expressions. Finally, MTT assay indicated that DMC significantly increased CDDP-induced cytotoxicity and was confirmed with an increased Bax/Bcl-2 ratio, indicating upregulation of caspase-3.

CONCLUSIONS

We concluded that enhancement of the cytotoxicity to CDDP by coadminstration with DMC was mediated by down-regulation of the expression of TP and ERCC1, regulated by PI3K-Akt-Snail pathway inactivation.

Protective Effects of Curcumin Against Nephrotoxic Agents

BACKGROUND

Curcumin is the one of the main phenolic ingredients in curcuma species rhizome. Curcuma species have traditionally been used for the treatment of diabetes, cardiovascular, and renal diseases.

METHODS

The present study was designed to review the scientific literature on the protective effects of curcumin against nephrotoxic agents.

RESULTS

Studies have shown the protective effects of curcumin against nephrotoxic agents such as gallic acid, glucose, tartrazine, streptozotocin, lead, cadmium, fluoride, maleate, malathion, nicotine, cisplatin, gentamicin, and methotrexate. However, further investigations are needed to determine the efficacy of curcumin as an antidote agent due to the lack of clinical trial studies. Therefore, it is recommended to conduct clinical trials in humans to confirm these effects.

CONCLUSION

The current review indicated that curcumin may be effective against nephrotoxicity by modulating oxidative stress and inflammatory responses.

Natural Product Interventions for Chemotherapy and Radiotherapy-Induced Side Effects

Cancer is the second leading cause of death in the world. Chemotherapy and radiotherapy are the common cancer treatments. However, the development of adverse effects resulting from chemotherapy and radiotherapy hinders the clinical use, and negatively reduces the quality of life in cancer patients. Natural products including crude extracts, bioactive components-enriched fractions and pure compounds prepared from herbs as well as herbal formulas have been proved to prevent and treat cancer. Of significant interest, some natural products can reduce chemotherapy and radiotherapy-induced oral mucositis, gastrointestinal toxicity, hepatotoxicity, nephrotoxicity, hematopoietic system injury, cardiotoxicity, and neurotoxicity. This review focuses in detail on the effectiveness of these natural products, and describes the possible mechanisms of the actions in reducing chemotherapy and radiotherapy-induced side effects. Recent advances in the efficacy of natural dietary supplements to counteract these side effects are highlighted. In addition, we draw particular attention to gut microbiotan in the context of prebiotic potential of natural products for the protection against cancer therapy-induced toxicities. We conclude that some natural products are potential therapeutic perspective for the prevention and treatment of chemotherapy and radiotherapy-induced side effects. Further studies are required to validate the efficacy of natural products in cancer patients, and elucidate potential underlying mechanisms.

Effect of curcumin on glycerol-induced acute kidney injury in rats

The aim of this study was to investigate the protective role and underlying mechanisms of curcumin on glycerol-induced acute kidney injury (AKI) in rats. Glycerol (10 ml/kg BW, 50% v/v in sterile saline, i.m.) was used to induce AKI, followed by curcumin (200 mg/kg/day, p.o.) administration for 3 days. To confirm renal damage and the effects of curcumin on AKI, serum BUN, Scr, and CK as well as renal SOD, MDA, GSH-Px were measured. Additionally, morphological changes were identified by H&E staining and transmission electron microscopy. The expression of several factors including chemotactic factor MCP-1, proinflammatory cytokines including TNF-α and IL-6, as well as the kidney injury markers, as Kim-1 and Lipocalin-2 were also assessed using q-PCR. Finally, cell apoptosis in renal tissue was detected using in situ TUNEL apoptosis fluorescence staining and expression of proteins associated with apoptotic, oxidative stress and lipid oxidative related signaling pathways were detected using immunohistochemical staining and western blot. The results showed that curcumin exerts renoprotective effects by inhibiting oxidative stress in rhabdomyolysis-induced AKI through regulation of the AMPK and Nrf2/HO-1 signaling pathways, and also ameliorated RM-associated renal injury and cell apoptosis by activating the PI3K/Akt pathway.

Comparative analysis of protective effects of curcumin, curcumin-β-cyclodextrin nanoparticle and nanoliposomal curcumin on unsymmetrical dimethyl hydrazine poisoning in mice

The aim of this study was to compare the protective effects of curcumin, curcumin-β-cyclodextrin nanoparticle curcumin (BCD-CUR) and nanoliposomal curcumin (NLC) on unsymmetrical dimethylhydrazine (UDMH) induced poison in mice. Curcumin, BCD-CUR, and NLC were prepared and their properties of zeta potential, particle size, encapsulation efficiency, and loading capacity were characterized. Eighty-eight male ICR mice on normal chow diet were randomly divided into 11 groups, and intraperitoneally injected with UDMH alone, or together with different doses of curcumin, BCD-CUR or NLC daily for up to 10 d. Enzyme activities of serum alanine transaminase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were analyzed by fully-automatic analyzer and neurotransmitter levels were determined with high performance liquid chromatography (HPLC). 150 mg/kg curcumin treatment alone significantly reduced levels of serum ALT and LDH that were induced by UDMH and markedly increased level of γ-amino butyric acid (GABA) that were reduced by UDMH in the hippocampus. 150 mg/kg BCD-CUR not only decreased significantly the increase of ALT, LDH and glutamate (Glu) but also recovered levels of AST and GABA. 150 mg/kg NLC recovered profoundly levels of AST and GABA while decreased remarkably the UDMH induced increase of ALT, LDH, Glu and 5-hydroxytryptamine (5-HT). In addition, treatments with all tested doses of NLC significantly reduced the UMDH induced dopamine (DA), the monoamine neurotransmitter. NLC had more profound protective effects against liver and central nervous system injury induced by UDMH than a suspension of BCD-CUR or curcumin did in mice.

Indole-3-carbinol protects against cisplatin-induced acute nephrotoxicity: role of calcitonin gene-related peptide and insulin-like growth factor-1

Nephrotoxicity associated with the clinical use of the anticancer drug cisplatin is a limiting problem. Thus, searching for new protective measures is required. Indole-3-carbinol is a powerful anti-oxidant, anti-inflammatory and anti-tumor agent. The present study aimed to investigate the potential protective effect of indole-3-carbinol against cisplatin-induced acute nephrotoxicity in rats. Rats were pre-treated with 20 mg/kg indole-3-carbinol orally before giving cisplatin (7 mg/kg). Cisplatin-induced acute nephrotoxicity was demonstrated where relative kidney weight, BUN and serum creatinine were significantly increased. Increased oxidative stress was evident in cisplatin group where GSH and SOD tissue levels were significantly depleted. Also, lipid peroxidation and NOX-1 were increased as compared to the control. Additionally, renal expression of pro-inflammatory mediators was induced by cisplatin. Cisplatin-induced cell death was shown by increased caspase-3 and decreased expression of EGF, IGF-1 and IGF-1 receptor. Nephrotoxicity, oxidative stress, inflammation and apoptotic effects induced by cisplatin were significantly ameliorated by indole-3-carbinol pre-treatment. Besides, the role of CGRP in cisplatin-induced nephrotoxicity was explored. Furthermore, cisplatin cytotoxic activity was significantly enhanced by indole-3-carbinol pre-treatment in vitro. In conclusion, indole-3-carbinol provides protection against cisplatin-induced nephrotoxicity. Also, reduced expression of CGRP may play a role in the pathogenesis of cisplatin-induced renal injury.

Natural polyphenols: Influence on membrane transporters

Accumulated evidence has focused on the use of natural polyphenolic compounds as nutraceuticals since they showed a wide range of bioactivities and exhibited protection against variety of age-related disorders. Polyphenols have variable potencies to interact, and hence alter the activities of various transporter proteins, many of them classified as anion transporting polypeptide-binding cassette transporters like multidrug resistance protein and p-glycoprotein. Some of the efflux transporters are, generally, linked with anticancer and antiviral drug resistance; in this context, polyphenols may be beneficial in modulating drug resistance by increasing the efficacy of anticancer and antiviral drugs. In addition, these effects were implicated to explain the influence of dietary polyphenols on drug efficacy as result of food-drug interactions. However, limited data are available about the influence of these components on uptake transporters. Therefore, the objective of this article is to review the potential efficacies of polyphenols in modulating the functional integrity of uptake transporter proteins, including those terminated the effect of neurotransmitters, and their possible influence in neuropharmacology.

Protective effects of curcumin on acute gentamicin-induced nephrotoxicity in rats

Background: Gentamicin-induced nephrotoxicity is one of the most common causes of acute kidney injury (AKI). The phenotypic alterations that contribute to acute kidney injury include inflammatory response and oxidative stress. Curcumin has a wide range biological functions, especially as an antioxidant. This study was designed to evaluate the renoprotective effects of curcumin treatment in gentamicin-induced AKI. Methods: Gentamicin-induced AKI was established in female Sprague–Dawley rats. Rats were treated with curcumin (100 mg/kg body mass) by intragastric administration, once daily, followed with an intraperitoneal injection of gentamicin sulfate solution at a dose of 80 mg/kg body mass for 8 consecutive days. At days 3 and 8, the rats were sacrificed, and the kidneys and blood samples were collected for further analysis. Results: The animals treated with gentamicin showed marked deterioration of renal function, together with higher levels of neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM-1) in the plasma as compared with the controls. Animals that underwent intermittent treatment with curcumin exhibited significant improvements in renal functional parameters. We also observed that treatment with curcumin significantly attenuated renal tubular damage, apoptosis, and oxidative stress. Curcumin treatment exerted anti-apoptosis and anti-oxidative effects by up-regulating Nrf2/HO-1 and Sirt1 expression. Conclusions: Our data clearly demonstrate that curcumin protects kidney from gentamicin-induced AKI via the amelioration of oxidative stress and apoptosis of renal tubular cells, thus providing hope for the amelioration of gentamicin-induced nephrotoxicity.

The renoprotective effect of curcumin in cisplatin-induced nephrotoxicity

The polyphenol curcumin has several pharmacological effects, including antioxidant, anti-inflammatory and anti-cancer features. In this study, we evaluated the effects of curcumin in cisplatin-induced nephrotoxicity in rats. Male Wistar rats were divided into four groups: (1) control; (2) cisplatin (7 mg/kg body weight, intraperitoneal as a single dose); (3) curcumin (100 mg/kg via gavage, for 10 days); and (4) cisplatin and curcumin. The cisplatin-treated rats exhibited kidney injury manifested by increased serum urea and creatinine (p<0.05). The kidney tissue from the cisplatin treated rats also exhibited a significant increase in the malondialdehyde (MDA) levels (p<0.05). The treatment with curcumin prevented a rise in the serum urea, creatinine and MDA levels when compared to the control group kidneys (p<0.05). The analysis the nicotinamide phosphoribosyltransferase (NAMPT) and sirtuin (SIRT) proteins (SIRT1, SIRT3 and SIRT4), which play important roles in the resistance to stress and the modulation of the threshold of cell death, showed similar trends (p<0.05). In the cisplatin-only treated rats, the induced renal injury decreased the levels of the NAMPT and SIRT proteins. Conversely, the curcumin increased the levels of the NAMPT and SIRT proteins in the cisplatin-treated rats (p<0.05). These data suggest that curcumin can potentially be used to reduce chemotherapy-induced nephrotoxicity, thereby enhancing the therapeutic window of cisplatin.

The protective effect of pomegranate extract against cisplatin toxicity in rat liver and kidney tissue

OBJECTIVES

The purpose of this study was to perform a histopathological investigation, at the light microscopy level, of the protective effects of pomegranate extract in cisplatin-induced liver and kidney damage in rats.

MATERIAL AND METHODS

Twenty-eight adult male Wistar albino rats were randomly divided into four groups of seven animals: Group 1: Control; Group 2: Treated for 10 consecutive days by gavage with pomegranate juice (2 ml/kg/day); Group 3: Injected intraperitoneally with cisplatin (8 mg/kg body weight, single dose) onset of the day 5, and Group 4: Treated by gavage with pomegranate juice 10 days before and after a single injection of cisplatin onset of the day 5. After 10 days, the animals were sacrificed and their kidneys and liver tissue samples were removed from each animal after experimental procedures. Cisplatin-induced renal and hepatic toxicity and the effect of pomegranate juice were evaluated by histopatological examinations.

RESULTS

In the kidney tissue, pomegranate juice significantly ameliorated cisplatin-induced structural alterations when compared with the cisplatin alone group. But in the liver tissue, although pomegranate juice attenuated the cisplatin-induced toxicity only in two rats, significant improvement was not observed.

CONCLUSION

In conclusion, these results demonstrate that the anti-oxidant pomegranate juice might have a protective effect against cisplatin-induced toxicity in rat kidney, but not in liver. Pomegranate juice could be beneficial as a dietary supplement in patients receiving chemotherapy medications.

Long-term aerobic exercise protects against cisplatin-induced nephrotoxicity by modulating the expression of IL-6 and HO-1

Nephrotoxicity is substantial side effect for 30% of patients undergoing cancer therapy with cisplatin and may force them to change or even abandon the treatment. Studies regarding aerobic exercise have shown its efficacy for the treatment of many types of diseases and its capacity to reduce tumors. However, little is known about the impact of physical exercise on cisplatin-induced acute kidney injury (AKI). In the present study, our aim was to investigate the role of physical exercise in AKI induced by cisplatin. We submitted C57Bl6 male mice to seven weeks of chronic exercise on a training treadmill and treated them with single i.p. injection of cisplatin (20 mg/kg) in the last week. Exercise efficacy was confirmed by an increased capillary-to-fiber ratio in the gastrocnemius muscle of exercised groups (EX and CIS-EX). The group submitted to exercise before cisplatin administration (CIS-EX) exhibited less weight loss and decreased serum urea levels compared to the cisplatin group (CIS). Exercise also showed a protective role against cisplatin-induced cell death in the kidney. The CIS-EX group showed a lower inflammatory response, with less TNF and IL-10 expression in the kidney and serum. In the same group, we observed an increase of IL-6 and HO-1 expression in the kidney. Taken together, our results indicate that chronic aerobic exercise is able to attenuate AKI by inducing IL-6 and HO-1 production, which results in lower inflammatory and apoptotic profiles in the kidney.

Curcumin prevents maleate-induced nephrotoxicity: relation to hemodynamic alterations, oxidative stress, mitochondrial oxygen consumption and activity of respiratory complex I

The potential protective effect of the dietary antioxidant curcumin (120 mg/Kg/day for 6 days) against the renal injury induced by maleate was evaluated. Tubular proteinuria and oxidative stress were induced by a single injection of maleate (400 mg/kg) in rats. Maleate-induced renal injury included increase in renal vascular resistance and in the urinary excretion of total protein, glucose, sodium, neutrophil gelatinase-associated lipocalin (NGAL) and N-acetyl β-D-glucosaminidase (NAG), upregulation of kidney injury molecule (KIM)-1, decrease in renal blood flow and claudin-2 expression besides of necrosis and apoptosis of tubular cells on 24 h. Oxidative stress was determined by measuring the oxidation of lipids and proteins and diminution in renal Nrf2 levels. Studies were also conducted in renal epithelial LLC-PK1 cells and in mitochondria isolated from kidneys of all the experimental groups. Maleate induced cell damage and reactive oxygen species (ROS) production in LLC-PK1 cells in culture. In addition, maleate treatment reduced oxygen consumption in ADP-stimulated mitochondria and diminished respiratory control index when using malate/glutamate as substrate. The activities of both complex I and aconitase were also diminished. All the above-described alterations were prevented by curcumin. It is concluded that curcumin is able to attenuate in vivo maleate-induced nephropathy and in vitro cell damage. The in vivo protection was associated to the prevention of oxidative stress and preservation of mitochondrial oxygen consumption and activity of respiratory complex I, and the in vitro protection was associated to the prevention of ROS production.

S-allylcysteine prevents cisplatin-induced nephrotoxicity and oxidative stress

Objectives

Cisplatin (CP) is an antineoplastic agent that induces nephrotoxicity and oxidative stress. S-allylcysteine (SAC) is a garlic-derived antioxidant. This study aims to explore whether SAC protects against CP-induced nephrotoxicity in rats.

Methods

In the first stage, the SAC protective dose was determined by measuring renal damage and the oxidative stress markers malondialdehyde, oxidized proteins and glutathione in rats injected with CP. In the second stage, the effect of a single dose of SAC on the expression of nuclear factor-erythroid 2-related factor-2 (Nrf2), protein kinase C beta 2 (PKCβ2) and nicotinamide adenine dinucleotide phosphate oxidase subunits (p47phox and gp91phox) was studied. In addition, the effect of SAC on oxidative stress markers and on the activity of catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) in isolated proximal and distal tubules were evaluated.

Key findings

SAC (25 mg/kg) prevented the CP-induced renal damage and attenuated CP-induced decrease in Nrf2 levels and increase in PKCβ2, p47phox and gp91phox expression in renal cortex and oxidative stress and decrease in the activity of CAT, GPx and GR in proximal and distal tubules.

Conclusions

These data suggest that SAC provides renoprotection by attenuating CP-induced oxidative stress and decrease in the activity of CAT, GPx and GR.