A novel nanomicellar combination of fenretinide and lenalidomide shows marked antitumor activity in a neuroblastoma xenograft model

Purpose: Currently >50% of high-risk neuroblastoma (NB) patients, despite intensive therapy and initial partial or complete response, develop recurrent NB due to the persistence of minimal residual disease (MRD) that is resistant to conventional antitumor drugs. Indeed, their low therapeutic index prevents drug-dose escalation and protracted administration schedules, as would be required for MRD treatment. Thus, more effective and less toxic therapies are urgently needed for the management of MRD. To address this aim, we evaluated a new combination of fenretinide and lenalidomide, both endowed with antitumor activity and low-toxicity profiles. New nanomicelles were prepared as carriers for this combination to maximize bioavailability and accumulation at the tumor site because of the enhanced permeability and retention (EPR) effect. Experimental design: New nanomicelles containing the fenretinide\u2013lenalidomide combination (FLnMs) were prepared by a one-step method, providing high drug encapsulation and micelle dimensions suitable for tumor accumulation. Their administration to mice bearing human NB xenografts allowed us to evaluate their efficacy in comparison with the nanomicelles containing fenretinide alone (FnMs). Results: Treatment by FLnMs significantly decreased the tumor growth of NB xenografts. FLnMs were more active than FnMs despite comparable fenretinide concentrations in tumors, and lenalidomide alone did not show cytotoxic activity in vitro against NB cells. The tumor mass at the end of treatment with FLnMs was predominantly necrotic, with a decreased Ki-67 proliferation index. Conclusion: FLnMs provided superior antitumor efficacy in NB xenografts compared to FnMs. The enhanced efficacy of the combination was likely due to the antiangiogenic effect of lenalidomide added to the cytotoxic effect of fenretinide. This new nanomicellar combination is characterized by a low-toxicity profile and offers a novel therapeutic option for the treatment of high-risk tumors where the persistence of MRD requires repeated administrations of therapeutic agents over long periods of time to avoid recurrent disease

Biology of tumors of the peripheral nervous system

Tumors of the peripheral nervous system include neuroblastomas, pheochromocytomas, and neuroepitheliomas. Neuroblastomas and pheochromocytomas are adrenergic in origin and share certain genetic features, whereas neuroepitheliomas are thought to be cholinergic and are characterized by distinct genetic features. Neuroblastomas are characterized by deletion of the short arm of chromosome 1 (lp), amplification of the N-myc proto-oncogene, and hyperdiploidy in subsets of tumors. All three of these genetic features have prognostic value in subsets of patients. Allelic loss of 14q also occurs with increased frequency, but the prognostic importance of this abnormality is not known yet. Pheochromocytomas have not been studied as extensively, but allelic loss for 1 p appears to be a frequent change, and no clear examples of oncogene activation have been identified. Neuroepitheliomas are characterized by translocation between chromosomes 11 and 22. Although they have a characteristic pattern of proto-oncogene expression, it is not clear that any of these oncogenes are activated specifically, and no sites of allelic loss have been identified to date. Thus, cytogenetic and molecular analysis of neuroblastomas, pheochromocytomas, and neuroepitheliomas is useful in distinguishing them from each other and from other tumors in selected cases. Furthermore, certain genetic markers help predict a tumor's clinical behavior, especially for neuroblastoma

Biology of tumors of the peripheral nervous system

Tumors of the peripheral nervous system include neuroblastomas, pheochromocytomas, and neuroepitheliomas. Neuroblastomas and pheochromocytomas are adrenergic in origin and share certain genetic features, whereas neuroepitheliomas are thought to be cholinergic and are characterized by distinct genetic features. Neuroblastomas are characterized by deletion of the short arm of chromosome 1 (lp), amplification of the N-myc proto-oncogene, and hyperdiploidy in subsets of tumors. All three of these genetic features have prognostic value in subsets of patients. Allelic loss of 14q also occurs with increased frequency, but the prognostic importance of this abnormality is not known yet. Pheochromocytomas have not been studied as extensively, but allelic loss for 1 p appears to be a frequent change, and no clear examples of oncogene activation have been identified. Neuroepitheliomas are characterized by translocation between chromosomes 11 and 22. Although they have a characteristic pattern of proto-oncogene expression, it is not clear that any of these oncogenes are activated specifically, and no sites of allelic loss have been identified to date. Thus, cytogenetic and molecular analysis of neuroblastomas, pheochromocytomas, and neuroepitheliomas is useful in distinguishing them from each other and from other tumors in selected cases. Furthermore, certain genetic markers help predict a tumor's clinical behavior, especially for neuroblastoma