Nerve growth factor prevention of aged-rat sympathetic neuron injury by cisplatin, vincristine and taxol--in vitro explant study

2-Aminoethoxydiphenyl borate ameliorates functional and structural abnormalities in cisplatin-induced peripheral neuropathy

AIM OF THE STUDY

Cisplatin is a platinum-derived chemotherapeutic agent commonly used in the treatment of various tumors. Ototoxicity, nephrotoxicity, and peripheral neuropathy are the most common side effects of this drug. 2-Aminoethoxydiphenyl borate (2-APB), boron- containing compound, has some protective effects against various tissue damage. The present study aimed to investigate the potential protective effects of 2-APB on in vitro and in vivo cisplatin-induced neurotoxicity.

MATERIALS AND METHODS

MTT assay was used to determine cell viability in DRG cells. Peripheral neuropathy was induced in forty male Sprague-Dawley rats (200-250g) by administering cisplatin (3 mg/kg/week) intraperitoneally (i.p) for five weeks. 2-APB (2, 4, and 8 mg/kg, i.p) was administered. Mechanical allodynia, thermal hyperalgesia, cold allodynia, mechanical stimuli, motor coordination, and locomotor activity tests were performed. DRG cells and sciatic nerves were analyzed histologically. NGF, BDNF, TNF-α, GSH, MDA, and LDH levels were investigated in rat DRG tissue homogenates.

RESULTS

Our results revealed that 2-APB ameliorated cisplatin-induced neurotoxicity by improving mechanical and cold allodynia and motor coordination impairment. It also reduced cisplatin-induced structural toxicity in peripheral tissues.

CONCLUSION

These findings demonstrated that 2-APB could be considered as a potential therapeutic strategy for the treatment of cisplatin-induced peripheral neuropathy.

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.

Taxane induced neuropathy in patients affected by breast cancer: Literature review

Taxane induced neuropathy (TIN) is the most limiting side effect of taxane based chemotherapy, relative to the majority of breast cancer patients undergoing therapy with both docetaxel and paclitaxel. The symptoms begin symmetrically from the toes, because the tips of the longest nerves are affected for first. The patients report sensory symptoms such as paresthesia, dysesthesia, numbness, electric shock-like sensation, motor impairment and neuropathic pain. There is a great inter-individual variability among breast cancer women treated with taxanes, in fact 20-30% of them don't develop neurotoxicity. Actually, there is no standard therapy for TIN, although many medications, antioxidants and natural substances have been tested in vitro and in vivo. We will summarize all most recent literature data on TIN prevention and treatment, in order to reach an improvement in TIN management. Further studies are needed to evaluate new therapies that restore neuronal function and improve life quality of patients.

Anti-cancer drug induced neurotoxicity and identification of Rho pathway signaling modulators as potential neuroprotectants

Many chemotherapy drugs are known to cause significant clinical neurotoxicity, which can result in the early cessation of treatment. To identify and develop more effective means of neuroprotection it is important to understand the toxicity of these drugs at the molecular and cellular levels. In the present study, we examine the effects of paclitaxel (taxol), cisplatin, and methotrexate on primary rat neurons including hippocampal, cortical, and dorsal horn/dorsal root ganglion neuronal cultures. We found that all of these anti-cancer drugs induce substantial neurotoxicity evidenced by neurite degeneration. The neurons are capable of recovering after treatment withdrawal, but taxol exerts a biphasic effect that results in the collapse of processes days after treatment is withdrawn. After cisplatin and methotrexate treatment, we observed the degeneration of neuronal processes including the reduction of dendritic branching, length, and altered growth cone formation, indicating an abnormal arrangement of the actin cytoskeleton consistent with the involvement of Rho family small GTPases. Inhibiting RhoA downstream effector p160 ROCK/Rho kinase using Y-27632, or activating p75 neurotrophin receptor (p75 NTR) using non-peptide mimetic LM11A-31, were able to reverse the degeneration caused by cisplatin and methotrexate. Therefore, the neurotoxicity resulting from exposure to the anti-cancer drugs cisplatin and methotrexate can be alleviated by inhibiting Rho signaling pathway.