Protective effect of procaine hydrochloride on cisplatin-induced alterations in rat kidney

A new platinum-based prodrug candidate: Its anticancer effects in B50 neuroblastoma rat cells

AIMS

Neuroblastoma is a rare cancer that affects children, mostly under the age of 5. This type of cancer starts in very early forms of immature nerve cells or developing cells found in embryo or fetus. To date cisplatin represents one of the most potent antitumor agent known, however, the onset of systemic side effects and the induction of drug resistance limit its use in the clinic for long-term treatment. In the present study we have analysed the effects of a new compound of platinum(IV) conjugates, named Pt(IV)Ac-POA, which is able to generate a synergistic antineoplastic action when released along with cisplatin upon intracellular Pt(IV) → Pt(II) reduction.

MAIN METHODS

To assess the growth inhibition of the compounds under investigation, a cell viability test, i.e. the resazurin reduction assay was used on the B50 neuroblastoma rat cells. Further analysis on the cell cycle and metabolic alterations were carried out through flow cytometry. Morphological changes and activation of different cell death pathways after treatment, were observed at transmission electron microscope and by immunocytochemistry at fluorescence microscopy. Protein expression was examined by western blot analysis.

KEY FINDINGS

This compound bearing bioactive axial ligand, such as the active histone deacetylase inhibitor (HDACi) (2-propynyl)octanoic acid (POA), induced cell death through different pathways at a concentration ten times lower than cisplatin.

SIGNIFICANCE

The results showed that Pt(IV)Ac-POA could represent a promising improvement of Pt-based chemotherapy against neuroblastoma.

Cell-death assessment by fluorescent and nonfluorescent cytosolic and nuclear staining techniques

Apoptosis, a genetically programmed cellular event leads to biochemical and morphological changes in cells. Alterations in DNA caused by several factors affect nucleus and ultimately the entire cell leading to compromised function of the organ and organism. DNA, a master regulator of the cellular events, is an important biomolecule with regards to cell growth, cell death, cell migration and cell differentiation. It is therefore imperative to develop the staining techniques that may lead to visualize the changes in nucleus where DNA is housed, to comprehend the cellular pathophysiology. Over the years a number of nuclear staining techniques such as propidium iodide, Hoechst-33342, 4', 6-diamidino-2-phenylindole (DAPI), Acridine orange-Ethidium bromide staining, among others have been developed to assess the changes in DNA. Some nonnuclear staining techniques such as Annexin-V staining, which although does not stain DNA, but helps to identify the events that result from DNA alteration and leads to initiation of apoptotic cell death. In this review, we have briefly discussed some of the most commonly used fluorescent and nonfluorescent staining techniques that identify apoptotic changes in cell, DNA and the nucleus. These techniques help in differentiating several cellular and nuclear phenotypes that result from DNA damage and have been identified as specific to necrosis or early and late apoptosis as well as scores of other nuclear deformities occurring inside the cells.

Reduced glutathione and procaine hydrochloride protect the nucleoprotein structure of boar spermatozoa during freeze–thawing by stabilising disulfide bonds

One important change the head of boar spermatozoa during freeze–thawing is the destabilisation of its nucleoprotein structure due to a disruption of disulfide bonds. With the aim of better understanding these changes in frozen–thawed spermatozoa, two agents, namely reduced glutathione (GSH) and procaine hydrochloride (ProHCl), were added at different concentrations to the freezing media at different concentrations and combinations over the range 1–2 mM. Then, 30 and 240 min after thawing, cysteine-free residue levels of boar sperm nucleoproteins, DNA fragmentation and other sperm functional parameters were evaluated. Both GSH and ProHCl, at final concentrations of 2 mM, induced a significant (P < 0.05) increase in the number of non-disrupted sperm head disulfide bonds 30 and 240 min after thawing compared with the frozen–thawed control. This effect was accompanied by a significant (P < 0.05) decrease in DNA fragmentation 240 min after thawing. Concomitantly, 1 and 2 mM GSH, but not ProHCl at any of the concentrations tested, partially counteracted the detrimental effects caused by freeze–thawing on sperm peroxide levels, motility patterns and plasma membrane integrity. In conclusion, the results show that both GSH and ProHCl have a stabilising effect on the nucleoprotein structure of frozen–thawed spermatozoa, although only GSH exerts an appreciable effect on sperm viability.

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.

Cisplatin nephrotoxicity: mechanisms and renoprotective strategies

Cisplatin is one of the most widely used and most potent chemotherapy drugs. However, side effects in normal tissues and organs, notably nephrotoxicity in the kidneys, limit the use of cisplatin and related platinum-based therapeutics. Recent research has shed significant new lights on the mechanism of cisplatin nephrotoxicity, especially on the signaling pathways leading to tubular cell death and inflammation. Renoprotective approaches are being discovered, but the protective effects are mostly partial, suggesting the need for combinatorial strategies. Importantly, it is unclear whether these approaches would limit the anticancer effects of cisplatin in tumors. Examination of tumor-bearing animals and identification of novel renoprotective strategies that do not diminish the anticancer efficacy of cisplatin are essential to the development of clinically applicable interventions.

Comparative nephrotoxicity of cisplatin and new octahedral Pt(IV) complexes

PURPOSE

Previously, we have reported that the newly synthesized octahedral Pt(IV) compound, trans,cis-Pt(acetato)(2)Cl(2)(1,4-butanediamine), K101 and trans,cis-Pt(trifluoroacetato)(2)Cl(2)(1,4-butanediamine), K102 showed potent antitumor activities in vitro and in vivo. In order to compare the nephrotoxicity of the newly synthesized Pt(IV) complexes, K102 and K102 with cisplatin, we performed various tests.

MATERIALS AND METHODS

We performed a single dose acute toxicity test for LD(50) values determination, biochemical assays in blood serum, acid phosphatase enzyme histochemistry and transmission electron microscopic studies in renal proximal tubular cells in mice in vivo. The route of drugs administration is intraperitoneal injection.

RESULTS

In biochemical assays, the serum levels of BUN were significantly elevated at 6 h (p < 0.001), 1 day (p < 0.05) and 3 days (p < 0.001) after injection in cisplatin treated mice (6 mg/kg, single dose, i.p.). On the other hand, the serum levels of BUN were slightly elevated at 6 h (p < 0.01) only in K101 treated mice (8.2 mg/kg, single dose, i.p.), and were significantly raised at 6 h, 1 and 3 days (p < 0.05) after injection in K102 treated mice (6.2 mg/kg, single dose, i.p.). The higher serum BUN level in K102 treated mice is considered that K102 possesses more lipophilic fluoro group than acetyl group in K101. The values of creatinine and uric acid were similar in all groups. The ultrastructural morphological changes of K101- or K102-administrated mice were less remarkable than cisplatin-administrated mice. In acid phosphatase enzyme histochemistry, cisplatin treatment induced relevant changes in the distribution pattern of enzyme activity compared with K101 or K102 treatment at 7 days after injection.

CONCLUSIONS

In conclusion, these results show that K101 is less nephrotoxic than cisplatin and a promising new platinum complex.

Agents ameliorating or augmenting the nephrotoxicity of cisplatin and other platinum compounds: a review of some recent research

Cisplatin (cis-diamminedichloroplatinum (II)) is an effective agent against various solid tumours. Despite its effectiveness, the dose of cisplatin that can be administered is limited by its nephrotoxicity. Hundreds of platinum compounds (e.g. carboplatin, oxaliplatin, nedaplatin and the liposomal form lipoplatin) have been tested over the last two decades in order to improve the effectiveness and to lessen the toxicity of cisplatin. Several agents have been tested to see whether they could ameliorate or augment the nephrotoxicity of platinum drugs. This review summarizes these studies and the possible mechanisms of actions of these agents. The agents that have been shown to ameliorate experimental cisplatin nephrotoxicity include antioxidants (e.g. melatonin, vitamin E, selenium, and many others), modulators of nitric oxide (e.g. zinc histidine complex), agents interfering with metabolic pathways of cisplatin (e.g. procaine HCL), diuretics (e.g. furosemide and mannitol), and cytoprotective and antiapoptotic agents (e.g. amifostine and erythropoietin). Only few of these agents have been tested in humans. Those agents that have been shown to augment cisplatin nephrotoxicity include nitric oxide synthase inhibitors, spironolactone, gemcitabine and others. Combining these agents with cisplatin should be avoided.

Cisplatin nephrotoxicity is critically mediated via the human organic cation transporter 2

Cis-platin is an effective anti-neoplastic agent, but it is also highly nephrotoxic. Here, we clearly identify the human organic cation transporter 2 (hOCT2) as the critical transporter for cis-platin nephrotoxicity in isolated human proximal tubules and offer a potential mechanism for reducing nephrotoxicity in clinical practice. Interaction of cis-platin with hOCT2 in kidney or hOCT1 in liver was investigated with the fluorescent cation 4-[4-(dimethyl-amino)styril]-methylpyridinium in stably transfected HEK293 cells and for the first time in tissues physiologically expressing these transporters, human proximal tubules, and human hepatocyte couplets. Cis-platin (100 micromol/L) inhibited transport via hOCT2-HEK293 but not hOCT1-HEK293. In human proximal tubules cis-platin competed with basolateral organic cation transport, whereas it had no effect in tubules from a diabetic kidney or in hepatocytes. In hOCT2-HEK293 cells treated for 15 hours, incubation with cis-platin induced apoptosis, which was completely suppressed by contemporaneous incubation with the hOCT2 substrate cimetidine (100 micromol/L). These findings demonstrate that uptake of cis-platin is mediated by hOCT2 in renal proximal tubules, explaining its organ-specific toxicity. A combination of cis-platin with other substrates that compete for hOCT2 offers an effective option to decrease nephrotoxicity in the clinical setting.

The influence of very low doses of Cisplatin on tumor cell proliferation in vitro and on some hematological and enzymatic parameters of healthy rats

Healthy rats had been treated for 2 or 6 weeks with 1.0 mL of 10(-8) and 10(-16) mg/mL of cisplatin. After 2 weeks of treatment, a significant increase in leukocyte and erythrocyte count and also in hematocrit was observed. Among leukocytes the number of neutrophils and eosinophils significantly increased. Biochemical analyses indicated a decrease in the glycogen content in the liver and kidneys after 2 weeks of treatment with low doses of cisplatin but at the end of the experiment (8th week of experiment) the stores of glycogen increased significantly. Biochemical analyses concerning the activity of some enzymes in the liver revealed a significant increase of peroxidase and acid phosphatase as well as catalase activities after 2 weeks of treatment. However, catalase was induced by a very low concentration of cisplatin, 10(-16) mg/mL. After the cessation of cisplatin treatment the activity of enzymes returned to normal values.Human lung carcinoma cell line A(549) (ECACC No 86012804) was also studied after treatment with the same doses of cisplatin and inhibition of its growth was observed. The results of these experiments strongly indicated that low doses of cisplatin could be stimulating for healthy cells but cytostatic for tumor cells.Possible mechanisms involved in the biological activity of very low cisplatin concentrations are discussed.