Use of Anticancer Platinum Compounds in Combination Therapies and Challenges in Drug Delivery

As one of the leading and most important metal-based drugs, platinum-based pharmaceuticals are widely used in the treatment of solid malignancies. Despite significant side effects and acquired drug resistance have limited their clinical applications, platinum has shown strong inhibitory effects for a wide assortment of tumors. Drug delivery systems using emerging technologies such as liposomes, dendrimers, polymers, nanotubes and other nanocompositions, all show promise for the safe delivery of platinum-based compounds. Due to the specificity of nano-formulations; unwanted side-effects and drug resistance can be largely averted. In addition, combinational therapy has been shown to be an effective way to improve the efficacy of platinum based anti-tumor drugs. This review first introduces drug delivery systems used for platinum and combinational therapeutic delivery. Then we highlight some of the recent advances in the field of drug delivery for combinational therapy; specifically progress in leveraging the cytotoxic nature of platinum-based drugs, the combinational effect of other drugs with platinum, while evaluating the drug targeting, side effect reducing and sitespecific nature of nanotechnology-based delivery platforms.

Oxidative stress response in canine in vitro liver, kidney and intestinal models with seven potential dietary ingredients

In vitro cell culture systems are a useful tool to rapidly assess the potential safety or toxicity of chemical constituents of food. Here, we investigated oxidative stress and organ-specific antioxidant responses by 7 potential dietary ingredients using canine in vitro culture of hepatocytes, proximal tubule cells (CPTC), bone marrow-derived mesenchymal stem cells (BMSC) and enterocyte-like cells (ELC). Cellular production of free radical species by denatonium benzoate (DB), epigallocatechin gallate (EPI), eucalyptol (EUC), green tea catechin extract (GTE) and sodium copper chlorophyllin (SCC), tetrahydroisohumulone (TRA) as well as xylitol (XYL) were continuously measured for reactive oxygen/nitrogen species (ROS/RNS) and superoxide (SO) for up to 24h. DB and TRA showed strong prooxidant activities in hepatocytes and to a lesser degree in ELC. DB was a weak prooxidant in BMSC. In contrast DB and TRA were antioxidants in CPTC. EPI was prooxidant in hepatocytes and BMSC but showed prooxidant and antioxidant activity in CPTC. SCC in hepatocytes (12.5mg/mL) and CPTC (0.78mg/mL) showed strong prooxidant and antioxidant activity in a concentration-dependent manner. GTE was effective antioxidant only in ELC. EUC and XYL did not induce ROS/RNS in all 4 cell types. SO production by EPI and TRA increased in hepatocytes but decreased by SCC in hepatocytes and ELC. These results suggest that organ-specific responses to oxidative stress by these potential prooxidant compounds may implicate a mechanism of their toxicities.

Phytochemistry and Biology of Loranthus parasiticus Merr, a Commonly Used Herbal Medicine

Loranthus parasiticus Merr (L. parasiticus) is a member of Loranthaceae family and is an important medicinal plant with a long history of Chinese traditional use. L. parasiticus, also known as Sang Ji Sheng (in Chinese), benalu teh (in Malay) and baso-kisei (in Japanese), is a semiparasitic plant, which is mostly distributed in the southern and southwestern regions of China. This review aims to provide a comprehensive overview of the ethnomedicinal use, phytochemistry and pharmacological activity of L. parasiticus and to highlight the needs for further investigation and greater global development of the plant's medicinal properties. To date, pharmacological studies have demonstrated significant biological activities, which support the traditional use of the plant as a neuroprotective, tranquilizing, anticancer, immunomodulatory, antiviral, diuretic and hypotensive agent. In addition, studies have identified antioxidative, antimutagenic, antiviral, antihepatotoxic and antinephrotoxic activity. The key bioactive constituents in L. parasiticus include coriaria lactone comprised of sesquiterpene lactones: coriamyrtin, tutin, corianin, and coriatin. In addition, two proanthocyanidins, namely, AC trimer and (+)-catechin, have been recently discovered as novel to L. parasiticus. L. parasiticus usefulness as a medicinal plant with current widespread traditional use warrants further research, clinical trials and product development to fully exploit its medicinal value.

Evaluation of biochemical effects of Casuarina equisetifolia extract on gentamicin-induced nephrotoxicity and oxidative stress in rats. Phytochemical analysis

Nephrotoxicity is defined as renal dysfunction that arises as result of exposure to external agents such as drugs and environmental chemicals. The present work was undertaken to carry out the phytochemical study and nephroprotective activity of methanolic extract of Casuarina equisetifolia leaves in gentamicin-induced nephrotoxicity in Wistar rats. Flavonoids and phenolic acids were identified and quantified using high performance liquid chromatography. Subcutaneous injection of rats with gentamicin (80 mg/kg body weight/day) for six consecutive days induced marked acute renal toxicity, manifested by a significant increase in serum urea, creatinine and uric acid levels, along with a significant depletion of serum potassium level, compared to normal controls. Also oxidative stress was noticed in renal tissue as evidenced by a significant decrease in glutathione level, superoxide dismutase, glutathione-S-transferase activities, also a significant increase in malondialdehyde and nitric oxide levels when compared to control group. Administration of plant extract at a dose of 300 mg/kg once daily for 4 weeks restored normal renal functions and attenuated oxidative stress. In conclusion, Casuarina equisetifolia leaves extract ameliorates gentamicin-induced nephrotoxicity and oxidative damage by scavenging oxygen free radicals, decreasing lipid peroxidation and improving intracellular antioxidant defense, thus extract may be used as nephroprotective agent.

Protective effects of curcumin against sodium fluoride-induced toxicity in rat kidneys

In the present study, the protective effect of curcumin against sodium fluoride-induced nephrotoxicity was evaluated in rats. Renal injury was induced by daily administration of 600 ppm sodium fluoride in drinking water for 1 week. One week before the administration of fluoride, the animals selected as study group were given curcumin (10 and 20 mg/kg body weight, intraperitoneally). After 1 week, lipid peroxidation level, activities of superoxide dismutase, catalase, and level of glutathione in kidney homogenate were measured. Blood serum samples were examined for creatinine, serum urea, and blood urea nitrogen levels. Another group of rats received vitamin C (10 mg/kg) as standard antioxidant. The results show that curcumin and vitamin C treatment prior to fluoride administration normalized the levels of serum creatinine, serum urea, and blood urea nitrogen. Moreover, curcumin and vitamin C administrations prevented the antioxidant enzyme decreasing and lipid peroxidation levels imbalance. In conclusion, curcumin treatment at the doses of 10 and 20 mg/kg (intraperitoneally) showed significant nephroprotective effects.

Comparative nephrotoxicity of Cisplatin and nedaplatin: mechanisms and histopathological characteristics

The antineoplastic platinum complexes cisplatin and its analogues are widely used in the chemotherapy of a variety of human malignancies, and are especially active against several types of cancers. Nedaplatin is a second-generation platinum complex with reduced nephrotoxicity. However, their use commonly causes nephrotoxicity due to a lack of tumor tissue selectivity. Several recent studies have provided significant insights into the molecular and histopathological events associated with nedaplatin nephrotoxicity. In this review, we summarize findings concerning the renal histopathology and molecular pathogenesis induced by antineoplastic platinum complexes, with a particular focus on the comparative nephrotoxicity of cisplatin and nedaplatin in rats.

The genome-wide expression profile of Curcuma longa-treated cisplatin-stimulated HEK293 cells

AIM

The rhizome of turmeric, Curcuma longa (CL), is a herbal medicine used in many traditional prescriptions. It has previously been shown that CL treatment showed greater than 47% recovery from cisplatin-induced cell damage in human kidney HEK 293 cells. This study was conducted to evaluate the recovery mechanisms of CL that occur during cisplatin induced nephrotoxicity by examining the genome wide mRNA expression profiles of HEK 293 -cells.

METHOD

Recovery mechanisms of CL that occur during cisplatin-induced nephrotoxicity were determined by microarray, real-time PCR, immunofluorescent confocal microscopy and Western blot analysis.

RESULTS

The results of microarray analysis and real-time PCR revealed that NFκB pathway-related genes and apoptosis-related genes were down-regulated in CL-treated HEK 293 cells. In addition, immunofluorescent confocal microscopy and Western blot analysis revealed that NFκB p65 nuclear translocation was inhibited in CL-treated HEK 293 cells. Therefore, the mechanism responsible for the effects of CL on HEK 293 cells is closely associated with regulation of the NFκB pathway.

CONCLUSION

CL possesses novel therapeutic agents that can be used for the prevention or treatment of cisplatin-induced renal disorders.

The genome-wide expression profile of Paeonia suffruticosa-treated cisplatin-stimulated HEK 293 cells

The root cortex of Paeonia suffruticosa Andrews (PS) is a crude Chinese drug used in many traditional prescriptions. This study was conducted to evaluate the recovery mechanisms induced by PS in HEK 293 cells treated with cisplatin. Previous studies revealed that 1μg/ml PS treatment showed greater than 20% recovery of 14μM cisplatin-induced 50% loss of cell proliferation (IC(50)) determined by mitochondrial activity MTS assay in HEK 293 cells (Sohn et al., 2009). In the present study, the effects of PS on gene expression profiles in stimulated HEK 293 cells were evaluated by oligonucleotide microarray and real-time RT-PCR. The results of the microarray analysis and real-time RT-PCR revealed that DNA repair- and cell proliferation-related genes were up-regulated in PS-treated HEK 293 cells. The mechanism responsible for the effects of PS on HEK 293 cells is closely associated with the regulation of DNA repair and cell proliferation. Thus, PS possesses novel therapeutic potential that could be used for the prevention or treatment of cisplatin-induced nephrotoxicity.

Screening of herbal medicines for the recovery of cisplatin-induced nephrotoxicity

The goal of this study was to quantitatively determine the recovery effects of herbal medicines (HM) on the cisplatin-induced nephrotoxicity. In the present study, the recovery effects of 239 HM on HEK 293 cells that had been damaged by cisplatin were evaluated by a mitochondrial activity MTS assay. After the first round of screening, candidate HM were selected based on a recovery rate of greater than 20%. The efficacy of the selected herbs was then determined by dose response kinetic analysis. Of the extracts evaluated, 7 HM (Paeonia suffruticosa (PS), Curcuma longa (CL), Centipeda minima (CM), Loranthus parasiticus (LP), Pulsatilla dahurica (PD), Sinapis alba (SA), and Scutellaria barbata (SB)) had a strong recovery effect on cisplatin-induced damage in HEK 293 cells. An LDH assay showed that LP, CM, SB, CL, SA, and PS had the best recovery effect, whereas a comet assay indicated that PS, SB, SA, PD, and CL had the best recovery effect. Taken together, these results suggest that SB, CL, PS, and SA are the best candidate HM for the recovery of cisplatin-induced nephrotoxicity. Therefore, additional studies should be conducted to determine if these HM possess novel therapeutic agents that can be used for the prevention or treatment of renal disorders.

Candesartan Differentially Regulates Epithelial Sodium Channel in Cortex Versus Medulla of Streptozotocin-Induced Diabetic Rats

Diabetes is associated with an activated renal renin-angiotensin-aldosterone system (RAAS) and it was shown that streptozotocin (STZ)-induced diabetic rats had increased whole kidney protein levels of the epithelial sodium channel subunits (α-, β- and γ-ENaC). However, the role of the RAAS on the regional, i.e., cortical versus medullary, regulation of ENaC is unclear. Male Sprague-Dawley rats were injected with STZ (intravenous, 65 mg/kg·bw, n=12/group). After 14 days, half of them received drinking water with candesartan (2 mg/kg·bw/day), an angiotensin-II type-1 receptor (AT1R) antagonist, for one week. In the medulla, i.e., inner stripe of the outer medulla (ISOM), base and/or tip of the inner medulla, immunoblotting revealed increased protein abundances of α1 Na-K-ATPase and ENaC subunits with diabetes (200-600% of controls), which were not reversed by candesartan. In fact, candesartan increased all ENaC subunits and α1 Na-K-ATPase in the ISOM and/or base in control rats. In contrast, in the cortex, diabetes did not increase these proteins. However, candesartan reduced cortical β- and γ-ENaC regardless of diabetic state. In summary, diabetes-induced increases in ENaC were seen preferentially in the medulla. These changes appeared to be due to a mechanism clearly distinct from AT1R activation, because they were not abolished by candesartan. In fact, candesartan treatment tended to increase some of these medullary proteins, perhaps in compensation for increased NaCl load. In contrast, cortical β- and γ-ENaC were reduced by candesartan regardless of diabetic state suggesting their regulation by AT1R at this site; however this did not appear to be a site of diabetes-induced ENaC up-regulation.

Screening of herbal medicines for recovery of acetaminophen-induced nephrotoxicity

This study was conducted to quantitatively evaluate the recovery effects of herbal medicines on acetaminophen-induced nephrotoxicity. In the present study, the recovery effects of 251 herb medicines on HEK 293 cells that had been damaged by acetaminophen were evaluated using an MTS assay. HEK 293 cells were cultured in 96-well plates and then pretreated with or without 20μM acetaminophen (IC(50) value: 17.5±1.9) for 1h. Next, different herbal medicines were added to the wells, after which the cells were reincubated at 37°C for 24h. After the first round of screening, the candidate herbal medicines were selected based on a recovery rate of greater than 20% and their efficacy were then determined by dose response kinetic analysis. Among these extracts, 8 herbal medicines (Ledebouriella divaricata, Sparganium simplex, Panax ginseng, Aster tataricus, Citrus aurantium, Sanguisorba officianlis, Arisaema consanguineum, and Polygonum aviculare) had a strong recovery effect on acetaminophen-induced damage in HEK 293 cells. Dose response non-linear regression analysis demonstrated that P. aviculare showed the best recovery rate (98%), and that its EC(50) (0.1ng/mL) was the smallest among the screened candidate herbal medicines. Additional studies of these herbal medicines should be conducted to determine if they possess novel therapeutic agents for the prevention or treatment of renal disorders.

Toxicogenomics: transcription profiling for toxicology assessment

Toxicogenomics, the application of transcription profiling to toxicology, has been widely used for elucidating the molecular and cellular actions of chemicals and other environmental stressors on biological systems, predicting toxicity before any functional damages, and classification of known or new toxicants based on signatures of gene expression. The success of a toxicogenomics study depends upon close collaboration among experts in different fields, including a toxicologist or biologist, a bioinformatician, statistician, physician and, sometimes, mathematician. This review is focused on toxicogenomics studies, including transcription profiling technology, experimental design, significant gene extraction, toxicological results interpretation, potential pathway identification, database input and the applications of toxicogenomics in various fields of toxicological study.