Aaron Levine

U12-dependent introns are found in small numbers in most eukaryotic genomes, but their scarcity makes accurate characterisation of their properties challenging. A computational search for U12-dependent introns was performed using the draft version of the human genome sequence. Human expressed sequences confirmed 404 U12-dependent introns within the human genome, a 6-fold increase over the total number of non-redundant U12-dependent introns previously identified in all genomes. Although most of these introns had AT-AC or GT-AG terminal dinucleotides, small numbers of introns with a surprising diversity of termini were found, suggesting that many of the non-canonical introns found in the human genome may be variants of U12-dependent introns and, thus, spliced by the minor spliceosome. Comparisons with U2-dependent introns revealed that the U12-dependent intron set lacks the 'short intron' peak characteristic of U2-dependent introns. Analysis of this U12-dependent intron set confirmed reports of a biased distribution of U12-dependent introns in the genome and allowed the identification of several alternative splicing events as well as a surprising number of apparent splicing errors. This new larger reference set of U12-dependent introns will serve as a resource for future studies of both the properties and evolution of the U12 spliceosome.

BACKGROUND: Cell therapies are an emerging form of healthcare that offer significant potential to improve the practice of medicine and provide benefits to patients who currently have limited or no treatment options. Ideally, these innovative therapies can complement existing small molecule, biologic and device approaches, forming a so-called fourth pillar of medicine and allowing clinicians to identify the best treatment approach for each patient. Despite this potential, cell therapies are substantially more complex than small molecule or biologic interventions. This complexity poses challenges for scientists and firms developing cell therapies and regulators seeking to oversee this growing area of medicine. RESULTS: In this project, we retrospectively examined the development of seven cell therapies - including three autologous interventions and four allogeneic interventions - with the aim of identifying common challenges hindering attempts to bring new cell therapies to market. We complemented this analysis with a series of qualitative interviews with experts in various aspects of cell therapy. Through our analysis, which included review of extant literature collected from company documents, newspapers, journals, analyst reports and similar sources, and analysis of the qualitative interviews, we identified several common challenges that cell therapy firms must address in both the pre- and post-market stages. Key pre-market challenges included identifying and maintaining stable funding to see firms through lengthy developmental timelines and uncertain regulatory processes. These challenges are not unique to cell therapies, of course, but the novelty of cell-based interventions complicates these efforts compared to small molecule or biologic approaches. The atypical nature of cell therapies also led to post-market difficulties, including challenges navigating the reimbursement process and convincing providers to change their treatment approaches. In addition, scaling up production, distributing cell therapies and managing the costs of production were challenges that started pre-market and continued into the post-market phase. CONCLUSIONS: Our analysis highlights several interrelated challenges hindering the development of cell therapies. Identifying strategies to address these challenges may accelerate the development and increase the impact of novel cell therapies.

AIMS: Driven by hype surrounding stem cell research, a number of clinics around the world currently offer 'stem cell therapies' to patients. These unproven interventions have attracted policy interest owing to the risks they may pose to patients and to the progress of legitimate translational stem cell research, yet remarkably little data exists about the patients who undergo these unproven therapies or their experiences. We sought to characterize this patient population. MATERIALS & METHODS: We developed a comprehensive data set of blogs written by patients (or their caretakers) about their experiences with unproven stem cell therapies. RESULTS & CONCLUSIONS: Analyzing these data suggests that unproven stem cell therapies are increasing rapidly in popularity and are attracting a wide range of patients--both young and old and with a diverse collection of medical conditions. These results should help clinicians advise individual patients and help policymakers devise strategies to mitigate the risks these treatments pose.