Effects of amifostine on cisplatin induced DNA adduct formation and toxicity in malignant glioma and normal tissues in rat

Intratumoral retrograde microdialysis treatment of high-grade glioma with cisplatin

PURPOSE

This study evaluates the application of a microdialysis technique for interstitial chemotherapy using cisplatin in high-grade glioma.

METHOD

An in vitro study demonstrated that cisplatin can be administered through retrograde microdialysis and defined the recovery for cisplatin. In a subsequent phase I study, 1-4 microdialysis catheters were implanted in tumor tissue, brain adjacent to tumor (BAT) tissue, and subcutaneous tissue in 10 patients with recurrent high-grade glioma. Cisplatin was administered continuously in daily doses between 0.3 and 3.9 mg for 4 to12 days. Microdialysis samples were continuously collected and analyzed for glucose metabolites, glutamate, glycerol, and cisplatin concentrations. Treatment tolerability was evaluated through clinical monitoring. Quality of life was assessed using the EORTC-QLQ-C30 questionnaire for up to 3 months after treatment.

RESULTS

This in vitro study showed that cisplatin could be administrated with a recovery of 41-97%, depending on flowrate, type of catheter, and cisplatin concentration. During the treatment, patients were exposed to a total dose of 1.2-36.8 mg cisplatin. The concentration of cisplatin in BAT, serum, and subcutaneous tissue was close to detection level in all but two patients. A transient neurologic deterioration due to edema was commonly observed, but no systemic side effects were recorded. After onset of treatment, concentrations of glutamate and glycerol were significantly increased in tumor tissue but not in BAT, with a peak after 3 days, and consistent for the rest of the treatment. Five of the patients survived between 153 and 492 days after treatment.

CONCLUSION

This phase I study demonstrates that retrograde microdialysis can be used to administer cisplatin interstitially into high-grade glioma tissue. A high cytotoxicity was detected in tumor tissue, but not in the surrounding brain. Retrograde microdialysis appears to be a clinically useful method for intratumoral drug administration in high-grade glioma.

Nasal administration of mesenchymal stem cells restores cisplatin-induced cognitive impairment and brain damage in mice

Cognitive impairments are a common side effect of chemotherapy that often persists long after treatment completion. There are no FDA-approved interventions to treat these cognitive deficits also called ‘chemobrain’. We hypothesized that nasal administration of mesenchymal stem cells (MSC) reverses chemobrain. To test this hypothesis, we used a mouse model of cognitive deficits induced by cisplatin that we recently developed. Mice were treated with two cycles of cisplatin followed by nasal administration of MSC. Cisplatin treatment induced deficits in the puzzle box, novel object/place recognition and Y-maze tests, indicating cognitive impairment. Nasal MSC treatment fully reversed these cognitive deficits in males and females. MSC also reversed the cisplatin-induced damage to cortical myelin. Resting state functional MRI and connectome analysis revealed a decrease in characteristic path length after cisplatin, while MSC treatment increased path length in cisplatin-treated mice. MSCs enter the brain but did not survive longer than 12-72 hrs, indicating that they do not replace damaged tissue. RNA-sequencing analysis identified mitochondrial oxidative phosphorylation as a top pathway activated by MSC administration to cisplatin-treated mice. Consistently, MSC treatment restored the cisplatin-induced mitochondrial dysfunction and structural abnormalities in brain synaptosomes. Nasal administration of MSC did not interfere with the peripheral anti-tumor effect of cisplatin. In conclusion, nasal administration of MSC may represent a powerful, non-invasive, and safe regenerative treatment for resolution of chemobrain.

Orofacial Pain in Cancer: Part I—Mechanisms

The mechanisms involved, and possible treatment targets, in orofacial pain due to cancer are poorly understood. The aim of the first of this two-part series is to review the involved pathophysiological mechanisms and explore their possible roles in the orofacial region. However, there is a lack of relevant research in the trigeminal region, and we have therefore applied data accumulated from experiments on cancer pain mechanisms in rodent spinal models. In the second part, we review the clinical presentation of cancer-associated orofacial pain at various stages: initial diagnosis, during therapy (chemo-, radiotherapy, surgery), and in the post-therapy period. In the present article, we provide a brief outline of trigeminal functional neuro-anatomy and pain-modulatory pathways. Tissue destruction by invasive tumors (or metastases) induces inflammation and nerve damage, with attendant acute pain. In some cases, chronic pain, involving inflammatory and neuropathic mechanisms, may ensue. Distant, painful effects of tumors include paraneoplastic neuropathic syndromes and effects secondary to the release of factors by the tumor (growth factors, cytokines, and enzymes). Additionally, pain is frequent in cancer management protocols (surgery, chemotherapy, and radiotherapy). Understanding the mechanisms involved in cancer-related orofacial pain will enhance patient management.

Amifostine (WR2721) confers DNA protection to in vivo cisplatin-treated murine peripheral blood leukocytes

Amifostine [S-2-3-aminopropyl amino ethyl phosphorotioic acid], a modulator agent for antineoplastic drugs involved in free radicals generation has given controversial results in cisplatin treated leukocytes in vitro. We have evaluated the amifostine protection over leukocytes in vivo, using comet assay. Groups of five OF1 male mice were given one of three doses of amifostine (56, 105 and 200 mg/Kg) after a cisplatin single injection (10 mg/Kg). Serum malonyldialdehyde levels, catalase and superoxide dismutase activity were also evaluated. Amifostine showed significant DNA protection (p< 0.01) at the two lower doses evaluated. Malonyldialdehyde decreased in all amifostine treatments with respect to cisplatin while antioxidant enzyme activities remained unchanged. However, DNA migration increased with the highest amifostine dose; in fact highest dose of amifostine did no protect damage caused by cisplatin this result have implications on amifostine treatment schedules in clinical practice.

Effects of amifostin in prevention of cisplatin induced nephrotoxicity in rats

Amifostine is a relatively new organic cytoprotective drug that is actually a prodrug aimed at reduction of cumulative renal toxicity induced by cisplatin repeated administration. The mechanism of amifostin nephroprotective effects has still not been clarified, but it is considered that this medicine has direct cytoprotective effect on kidney tubuli. The main aim of this study was to reveal the effect of amifostin in prevention of nephrotoxicity induced experimentally with long-term administration of cysplatin at dose of 2 mg/kg/b.w./per week during a period of 8 weeks. The results obtained have shown that amifostin, although not completely, but largely reduces nephrotoxicity induced with long-term administration of cisplatin.

Amifostine: is there evidence of tumor protection?

A large body of experimental evidence suggests that amifostine (Ethyol, WR-2721; MedImmune, Inc, Gaithersburg, MD) is a selective cytoprotector of normal tissues. Nevertheless, several experimental studies, most of which were conducted in the early 1980s, suggest that amifostine may protect tumor tissues, although to a much lower degree than its protective effect on normal tissues. Based on a critical literature review, we conclude that any experimental evidence suggesting tumor protection is weak. The effects of anesthesia and hypotension on normal and tumor tissue oxygenation status of animals, the consequences of such events on amifostine activity, and the impact of this complex situation on host immunity and radiotherapy efficacy in the experimental setting do not reliably simulate the clinical setting. Analyses of radiobiologic and histologic results of the Canine Sarcoma Study show that, if any conclusion is to be made, amifostine protected normal tissues and preserved (or even enhanced) the antitumor activity of radiotherapy. The Ormaplatin Study clearly showed a 10-fold decreased concentration of platinum in tumor compared with normal tissues, and does not therefore support evidence of lack of amifostine selectivity. Finally, not one clinical study suggests tumor protection with amifostine. On the contrary, the majority of clinical data strongly suggest that patients who receive amifostine with radiotherapy and/or chemotherapy do better than controls. Rather than organizing large-scale, randomized clinical trials to exclude tumor protection by amifostine, it seems more useful to design trials that would measure amifostine benefits in terms of improved quality of life, tumor control, and survival rates in patients being treated with standard or novel chemotherapy/radiotherapy regimens.

Comparative study between the interaction of dephosphorylated amifostine (WR-1065) and amoxicilline with pBR322 in absence and presence of cisplatin by AFM

The effect of the amoxicilline as a possible cisplatin-action protector on pBR322 DNA has been visually studied by atomic force microscopy in comparison with the modifications caused by the controversed cisplatin protector amifostine. Incubation of amoxicilline with the plasmid DNA showed aggregation and compaction of DNA. Cisplatin incubated in the same conditions with DNA produced kinks and super-coiling of the circular form. In the case of previous treatment of DNA with amoxicilline, the characteristic effect of cisplatin is only partially observed. The amoxicilline seemed to control the action of cisplatin on DNA. The initial effect of dephosphorylated amifostine (WR-1065) when this protector was incubated with the plasmid was also the formation of aggregates and the compaction of DNA. However, addition of cisplatin successively after 1 and 2 h showed the characteristic modification caused by cisplatin but only in a decreasing percentage of molecules of DNA. Both molecules, amoxicilline and WR-1065 seem to control the strong direct action of cisplatin on DNA. This effect can justify the role as protecting agent of amifostine on side effects caused by cisplatin and can open new possibilities to other agents like amoxicilline.

Peripheral neuropathy and cancer

Peripheral neuropathy has a major impact on quality of life and may limit the amount of treatment patients can receive. Neurotoxic agents are used increasingly in oncologic practice, yet clinicians are often unaware of the protean manifestations of neuropathy and find its management troubling. Recent knowledge about the mechanisms of neuropathic disease and new treatments may help to minimize the impact of neuropathy on this vulnerable patient population.

Amifostine in clinical oncology: current use and future applications

Amifostine (Ethyol), an inorganic thiophosphate, is a selective broad-spectrum cytoprotector of normal tissues that provides cytoprotection against ionizing radiation and chemotherapeutic agents, thus preserving the efficacy of radiotherapy and chemotherapy. This review summarizes the preclinical data and clinical experience with amifostine, and provides insight into future clinical directions. Amifostine, an inactive pro-drug, is transformed to an active thiol after dephosphorylation by alkaline phosphatase found in the normal endothelium. The absence of alkaline phosphatase in the tumoral endothelium and stromal components, and the hypovascularity and acidity of the tumor environment, may explain its cytoprotective selectivity. The cytoprotective mechanism of amifostine is complicated, involving free radical scavenging, DNA protection and repair acceleration, and induction of cellular hypoxia. Intravenous administration of amifostine 740-900 mg/m(2) before chemotherapy and 250-350 mg/m(2) before each radiotherapy fraction are widely used regimens. The US Food and Drug Administration has approved the use of amifostine as a cytoprotector for cisplatin chemotherapy and for radiation-induced xerostomia. Ongoing trials are being conducted to determine the efficacy of amifostine in reducing radiation-induced mucositis and other toxicities. Novel schedules and routes of administration are under investigation, and may further simplify the use of amifostine and considerably broaden its applications.