Cancer incidence is rising and this global challenge is further exacerbated by tumour resistance to available medicines. A promising approach to such unmet need for improved cancer treatment is drug repurposing. Here we highlight the potential for repurposing disulfiram (Antabuse), an old alcohol-aversion drug effective against diverse cancer types in preclinical studies. Our nationwide epidemiological study reveals that patients who continuously used disulfiram have a lower risk of death from cancer compared to those who stopped using the drug at their diagnosis. Moreover, we identify ditiocarb-copper complex as the metabolite of disulfiram responsible for anticancer effects, and provide methods to detect its preferential accumulation in tumours and candidate biomarkers for impact in cells and tissues. Finally, our functional and biophysical analyses reveal the long-sought molecular target of disulfiram’s tumour suppressing effects as NPL4, an adapter of p97/VCP segregase essential for protein turnover involved in multiple regulatory and stress-response cellular pathways.

MHC-peptide complexes mediate key functions in adaptive immunity. In a classical view, MHC-I molecules present peptides from intracellular source proteins, whereas MHC-II molecules present antigenic peptides from exogenous and membrane proteins. Nevertheless, substantial crosstalk between these two pathways has been observed. We investigated the influence of autophagy on the MHC-II ligandome and demonstrated that peptide presentation is altered considerably upon induction of autophagy. The presentation of peptides from intracellular and lysosomal source proteins was strongly increased on MHC-II in contrast with peptides from membrane and secreted proteins. In addition, autophagy influenced the MHC-II antigen-processing machinery. Our study illustrates a profound influence of autophagy on the class II peptide repertoire and suggests that this finding has implications for the regulation of CD4 ؉ T cell-mediated processes.antigen processing ͉ lysosomal proteases ͉ T helper cells P eptides of foreign and self proteins are presented on MHC-I and MHC-II molecules at the cell surface and can be recognized by CD8ϩ and CD4 ϩ T lymphocytes, respectively (1, 2). From a classical point of view, MHC-I molecules present antigenic peptides derived from intracellular proteins, whereas MHC-II molecules do so for exogenous and membrane proteins (3). This phenomenon is reflected in the two major cellular breakdown pathways for proteins: proteasomal degradation, particularly relevant to the generation of MHC-I peptides (4), and degradation by the endosomal͞lysosomal system, which is responsible for the processing of MHC-II peptides (5). However, the separation of these distinct pools of source proteins is less stringent than originally believed. It is now well established that MHC-I molecules are able to present peptides derived from exogenous antigens (Ag) by a process known as cross presentation (6). On the other hand, intracellular proteins can be presented by MHC-II molecules (7,8), even though the underlying processes are less clear. It has been recently shown that peptides from cytosolic model proteins can be presented on MHC-II molecules through autophagy (9-11). Autophagy plays a role in the endosomal͞lysosomal degradation pathway and is responsible for feeding intracellular components into this pathway. It is thought to be required for normal turnover of cellular components, particularly in response to starvation (12). Against this background, we hypothesized that autophagy might mediate MHC-II presentation of intracellular Ag, meaning the contents of a cell contained within the plasma membrane, excluding large vacuoles and secretory or ingested material (Gene Ontology classifications), in general. Therefore, we performed a detailed characterization of the MHC-II ligand repertoire (ligandome) presented at the cell surface under normal conditions and after increased autophagy, leading to a comprehensive overall picture of changes in peptide processing and presentation. Materials and MethodsCell Culture and Autophagy Inducti...

Purpose: Bortezomib (Velcade), a dipeptide boronate 20S proteasome inhibitor and an approved treatment option for multiple myeloma, is associated with a treatment-emergent, painful peripheral neuropathy (PN) in more than 30% of patients. Carfilzomib, a tetrapeptide epoxyketone proteasome inhibitor, currently in clinical investigation in myeloma, is associated with low rates of PN. We sought to determine whether PN represents a target-mediated adverse drug reaction (ADR).Experimental Design: Neurodegenerative effects of proteasome inhibitors were assessed in an in vitro model utilizing a differentiated neuronal cell line. Secondary targets of both inhibitors were identified by a multifaceted approach involving candidate screening, profiling with an activity-based probe, and database mining. Secondary target activity was measured in rats and patients receiving both inhibitors.Results: Despite equivalent levels of proteasome inhibition, only bortezomib reduced neurite length, suggesting a nonproteasomal mechanism. In cell lysates, bortezomib, but not carfilzomib, significantly inhibited the serine proteases cathepsin G (CatG), cathepsin A, chymase, dipeptidyl peptidase II, and HtrA2/Omi at potencies near or equivalent to that for the proteasome. Inhibition of CatG was detected in splenocytes of rats receiving bortezomib and in peripheral blood mononuclear cells derived from bortezomib-treated patients. Levels of HtrA2/Omi, which is known to be involved in neuronal survival, were upregulated in neuronal cells exposed to both proteasome inhibitors but was inhibited only by bortezomib exposure.Conclusion: These data show that bortezomib-induced neurodegeneration in vitro occurs via a proteasome-independent mechanism and that bortezomib inhibits several nonproteasomal targets in vitro and in vivo, which may play a role in its clinical ADR profile. Clin Cancer Res; 17(9); 2734-43. Ó2011 AACR.

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SummaryWith increasing number of therapies available for the treatment of multiple myeloma, it is timely to examine the course of patients' journeys. We investigated patient characteristics, treatment durations and outcomes, and symptom burden across the treatment pathway in Belgium, France, Germany, Italy, Spain, Switzerland and the UK. In total, 435 physicians retrospectively reviewed 4997 patient charts. Profiles of patients diagnosed with multiple myeloma during the last 12 months were similar across countries; bone pain was the most common presentation. Median duration of first‐line therapy was 6 months, followed by a median treatment‐free interval of 10 months; both these decreased with increasing lines of therapy, as did time to progression. Depth of response, as assessed by the treating physician, also decreased with each additional line of therapy: 74% of patients achieved at least a very good partial response at first line, compared with only 11% at fifth line. Deeper responses were associated with longer time to progression, although these were physician‐judged. Toxicities and co‐morbidities increased with later treatment lines, and were more likely to have led to discontinuation of treatment. These real‐world data provide an insight into patient outcomes and treatment decisions being made in clinical practice.