The use of the effective antineoplastic agent cisplatin is limited by its serious side effects , such as oto-and nephrotoxicity. Ototoxicity is a problem of special importance in children , because deafness hampers their language and psychosocial development. Recently , organic cation transporters (OCTs) were identified in vitro as cellular uptake mechanisms for cisplatin. In the present study , we investigated in an in vivo model the role of OCTs in the development of cisplatin oto-and nephrotoxicity. The functional effects of cisplatin treatment on kidney (24 hours excretion of glucose , water , and protein) and hearing (auditory brainstem response) were studied in wildtype and OCT1/2 double-knockout (KO) mice. No sign of ototoxicity and only mild nephrotoxicity were observed after cisplatin treatment of knockout mice. Comedication of wild-type mice with cisplatin and the organic cation cimetidine protected from ototoxicity and partly from nephrotoxicity. For the first time we showed that OCT2 is expressed in hair cells of the cochlea. Furthermore , cisplatin-sensitive cell lines from pediatric tumors showed no expression of mRNA for OCTs , indicating the feasibility of therapeutic approaches aimed to reduce cisplatin toxicities by competing OCT2-mediated cisplatin uptake in renal proximal tubular and cochlear hair cells. These findings are very important to establish chemotherapeutical protocols aimed to maximize the antineoplastic effect of cisplatin while reducing the risk of toxicities.

Key Points Use of native E coli asparaginase in induction leads to high hypersensitivity rates to PEGasparaginase in intensification. Switching to Erwinia asparaginase leads to effective asparaginase activity levels in most patients who experienced an allergy to PEGasparaginase.

Drug ototoxicity limits the quality of life of patients after treatment, having serious consequences, especially for psychosocial development of children. Although the ototoxicity of many drugs resolves after treatment discontinuation, the use of platinum derivatives and aminoglycosides is associated with permanent hearing loss. In this review, we have listed ototoxic drugs and the mechanisms by which they damage the ears. Moreover, possible protective strategies and important methods for early detection of ototoxic effects are discussed.

No abstract

The origin of malignant embryonal tumors is incompletely understood and certain risk groups remain difficult to treat. The epigenetic structure of DNA and its lesions play a role in the origin of these neoplasms. Manipulation of the epigenome may offer novel treatment options. The authors evaluated the cytotoxicity of histone deacetylase inhibitors (HDI) [MS-275, SAHA, TSA, M344, M360, D85, SW55, SW187 and valproic acid (VPA)] on 13 embryonal tumor cell lines [4 medulloblastomas, 5 neuroblastomas, 2 atypical teratoid/rhabdoid tumors (AT/RT), and 2 malignant rhabdoid tumors of the kidney (RTK)] in MTT assay. In addition, HDI effects on hyperacetylation, reexpression of growth regulatory genes and apoptosis were characterized by Western analysis, RT-PCR and annexin-V staining. All HDI inhibited cell proliferation in a time-and dose-dependent manner. VPA was least cytotoxic with GI 50 values after 72 hr ranging from 53.6 to 332.9 lM, while TSA was most efficient with GI 50 values after 72 hr ranging from 0.01 to 8.8 lM. M344 and M360 were also highly effective. Western blot revealed hyperacetylation of histone H4 after HDI treatment. Reactivation of several genes including the proapoptotic CASP8 was identified by RT-PCR. Annexin-V staining demonstrated a dose and time dependent induction of apoptosis. HDI inhibited the growth of medulloblastoma, neuroblastoma and rhabdoid tumors in vitro. Treatment with HDI induced the reactivation of growth regulatory genes and consequently apoptosis. Our results warrant further studies and may help in the design of new protocols geared at the treatment of high risk embryonal tumors. ' 2007 Wiley-Liss, Inc.