Radiopharmaceutical small-scale preparation in Europe: will we be able to harmonize the situation?

BACKGROUND: Radiopharmaceuticals have been considered a special group of medicines in Europe since 1989. The use of radiopharmaceuticals that have marketing authorization should always be the first option in clinical use, however due to their special properties the availability of approved radiopharmaceuticals is limited. For this reason, they can be produced on a small scale outside the marketing authorization process. MAIN BODY: The in-house radiopharmaceutical preparations represent an important source of these special medicines for routine nuclear medicine practice. However, a lack of harmonization in Member States' regulations leads to extreme differences in the use and availability of radiopharmaceuticals across Europe. The aim of this work is to provide an overview of the different national regulatory frameworks in which Directive 2001/83/UE is adopted on the preparation of radiopharmaceuticals outside the marketing authorization track in Europe. Nine different national regulations have been studied to describe how unlicensed radiopharmaceuticals are prepared. Special attention is paid to reflect the minimum standards that these preparations should meet as well as the educational requirements to be a radiopharmacist in charge of them. CONCLUSION: The rapid development of new radiopharmaceuticals used in radiometabolic therapy requires a common regulation that allows balance between the use and preparation of licensed and unlicensed radiopharmaceuticals. The absence of a harmonized regulation for the radiopharmaceutical small-scale preparation and the implementation of Good Manufacture Practices, leads to extreme differences in the use, quality assurance and availability of radiopharmaceuticals in Europe.

Genetic unmasking of an epigenetically silenced microRNA in human cancer cells.

The mechanisms underlying microRNA (miRNA) disruption in human disease are poorly understood. In cancer cells, the transcriptional silencing of tumor suppressor genes by CpG island promoter hypermethylation has emerged as a common hallmark. We wondered if the same epigenetic disruption can "hit" miRNAs in transformed cells. To address this issue, we have used cancer cells genetically deficient for the DNA methyltransferase enzymes in combination with a miRNA expression profiling. We have observed that DNA hypomethylation induces a release of miRNA silencing in cancer cells. One of the main targets is miRNA-124a, which undergoes transcriptional inactivation by CpG island hypermethylation in human tumors from different cell types. Interestingly, we functionally link the epigenetic loss of miRNA-124a with the activation of cyclin D kinase 6, a bona fide oncogenic factor, and the phosphorylation of the retinoblastoma, a tumor suppressor gene.

miR-33-mediated downregulation of p53 controls hematopoietic stem cell self-renewal.

Hematopoietic stem cells (HSCs) are defined by their exclusive capacity to both self-renew and to give rise to multipotent progenitors (MPPs) that in turn differentiate into the mature blood cell lineages. The tumor suppressor p53, in addition to its role in the regulation of the cell cycle, plays an important role in HSC self-renewal, although it has not fully resolved. Here we report that in super-p53 mice (sp53), which carry one extra gene dose of p53, the miR-33 is downregulated in HSCs and highly expressed in MPPs. Transplantation assays of miR-33-transduced sp53 HSC results in a significant acquisition of repopulating capacity and a decrease of recipients survival. Moreover, high levels of miR-33 represses the endogenous level of p53 protein in murine embryonic fibroblasts (MEFs), leads both to neoplastic transformation and anchorage independent growth of MEFs, and displays a decrease of apoptotic response using tumor-derived cell lines. Accordingly, we demonstrate that miR-33-mediated downregulation of p53 is dependent on the binding of miR-33 to two conserved motifs in the 3'UTR of p53. Together, these data show that the miR-33 modifies HSC repopulating efficiency of sp53 mice by impairing the p53 function. Defining the role of miR-33 in controlling the HSC self-renewal through p53 may lead to the prevention and treatment of hematopoietic disorders.

Molecular characterization of a t(9;12)(p21;q13) balanced chromosome translocation in combination with integrative genomics analysis identifies C9orf14 as a candidate tumor-suppressor.

A large number of nevi (LNN) is a high risk phenotypic trait for developing cutaneous malignant melanoma (CMM). In this study, the breakpoints of a t(9;12)(p21;q13) balanced chromosome translocation were finely mapped in a family with LNN and CMM. Molecular characterization of the 9p21 breakpoint identified a novel gene C9orf14 expressed in melanocytes disrupted by the translocation. Integrative analysis of functional genomics data was applied to determine the role of C9orf14 in CMM development. An analysis of genome-wide DNA copy number alterations in melanoma tumors revealed the loss of the C9orf14 locus, located proximal to CDKN2A, in approximately one-fourth of tumors. Analysis of gene expression data in cancer cell lines and melanoma tumors suggests a loss of C9orf14 expression in melanoma tumorigenesis. Taken together, our results indicate that C9orf14 is a candidate tumor-suppressor for nevus development and late stage melanoma at 9p21, a region frequently deleted in different types of human cancers.