ABSTRACT
Title
Oxaliplatin-induced neuropathy: oxidative mechanisms in nervous cells.
Authors
M. Zanardelli1
1 Dept. of Preclinical and Clinical Pharmacology, University of Florence, Italy.
1 Dept. of Preclinical and Clinical Pharmacology, University of Florence, Italy.
Abstract
Oxaliplatin is a platin-organic drug with anti-neoplastic properties used for colon-rectal cancer. As compared with others platinum derivates, that show significant renal impairment or ototoxicity, oxaliplatin has only a mild hematological and gastrointestinal toxicity. On the other hand, its limiting side effect is the neurotoxicity and a subsequent nerve hyperexcitability that results in a neuropathic syndrome. Neuropathy induced by oxaliplatin remains the most common limit for clinical use (Gamelin et al 2002).
In a rat model of painful oxaliplatin-induce neuropathy, we previously describe an hyperalgesic state characterized by a pattern of molecular and morphological alterations of nervous tissue. In particular, a significant cortical astrocyte activation has been described. Among biochemical signs we highlighted an involvement of oxidative stress in the oxaliplatin-induced neurodegenerative process. The “oxidative hypothesis” as molecular basis of neuropathy allow to plan an in vitro model of the chemotherapy-induced neurotoxicity. Aim of the present study is to set up a cellular system useful to screen new antioxidant compounds and to deep inside the molecular mechanisms of oxaliplatin neurotoxicity.
Experimental conditions (oxaliplatin concentrations and incubation times) able to induce cell damage, were studied in the human neuroblastoma cell line SHSY-5Y. Oxaliplatin 100 µM increased reactive oxygen species (ROS) levels, in particular superoxide anion production. Oxaliplatin-dependent ROS increase led to lipid peroxidation (evaluated by malonyl dialdehyde levels), protein oxidation (evaluated as carbonylated protein revealed by immunoblot) and DNA oxidation (measured as 8-OH-2-dG levels by ELISA method). Finally, 100 µM oxaliplatin activated caspase-3 apoptotic signalling in a time-dependent manner. 10 µM silibinin and α-tocopherol, two well known antioxidant compounds, were able to prevent the oxidative damage. On the contrary, the apoptotic process remained unaffected.
To study the glial component imply in the chemotherapeutic neurotoxicity, we used a primary culture of rat cortical astrocytes. Morphological alterations due to the oxaliplatin treatment were analyzed by fluorescent immunocytochemistry (GFAP marker). We performed the same experimental set also in this primary cells: oxaliplatin oxidative injury are reduced by the antioxidant tested. On the other hand in this condition silibinin and α-tocopherol (10 µM) was able to significantly limited caspase-3 activation suggesting for antioxidants a different antiapoptotic profile in respect to the cell type.
In order to exclude an antioxidant interference on the oxaliplatin anti-neoplastic mechanism of action, an human colon adenocarcinoma cells (HT29) was used. Neither silibinin nor α-tocopherol modify the oxaliplatin toxicity profile (lethal concentration 50 (LC50) and caspase 3 activation).
Gamelin (2002) Semin Oncol. 29 (5 Suppl 15), 21-33.
In a rat model of painful oxaliplatin-induce neuropathy, we previously describe an hyperalgesic state characterized by a pattern of molecular and morphological alterations of nervous tissue. In particular, a significant cortical astrocyte activation has been described. Among biochemical signs we highlighted an involvement of oxidative stress in the oxaliplatin-induced neurodegenerative process. The “oxidative hypothesis” as molecular basis of neuropathy allow to plan an in vitro model of the chemotherapy-induced neurotoxicity. Aim of the present study is to set up a cellular system useful to screen new antioxidant compounds and to deep inside the molecular mechanisms of oxaliplatin neurotoxicity.
Experimental conditions (oxaliplatin concentrations and incubation times) able to induce cell damage, were studied in the human neuroblastoma cell line SHSY-5Y. Oxaliplatin 100 µM increased reactive oxygen species (ROS) levels, in particular superoxide anion production. Oxaliplatin-dependent ROS increase led to lipid peroxidation (evaluated by malonyl dialdehyde levels), protein oxidation (evaluated as carbonylated protein revealed by immunoblot) and DNA oxidation (measured as 8-OH-2-dG levels by ELISA method). Finally, 100 µM oxaliplatin activated caspase-3 apoptotic signalling in a time-dependent manner. 10 µM silibinin and α-tocopherol, two well known antioxidant compounds, were able to prevent the oxidative damage. On the contrary, the apoptotic process remained unaffected.
To study the glial component imply in the chemotherapeutic neurotoxicity, we used a primary culture of rat cortical astrocytes. Morphological alterations due to the oxaliplatin treatment were analyzed by fluorescent immunocytochemistry (GFAP marker). We performed the same experimental set also in this primary cells: oxaliplatin oxidative injury are reduced by the antioxidant tested. On the other hand in this condition silibinin and α-tocopherol (10 µM) was able to significantly limited caspase-3 activation suggesting for antioxidants a different antiapoptotic profile in respect to the cell type.
In order to exclude an antioxidant interference on the oxaliplatin anti-neoplastic mechanism of action, an human colon adenocarcinoma cells (HT29) was used. Neither silibinin nor α-tocopherol modify the oxaliplatin toxicity profile (lethal concentration 50 (LC50) and caspase 3 activation).
Gamelin (2002) Semin Oncol. 29 (5 Suppl 15), 21-33.