Copper complexed DSF (DSF-Cu) also possesses anti-tumor and chemosensitizing properties; however, its molecular mechanisms of action remain unclear. and chemosensitizing properties; however, its molecular mechanisms of action remain unclear. Here we investigated malignant pleural mesothelioma (MPM) suppressive effects of DSF-Cu and the molecular mechanisms involved. DSF-Cu inhibited growth of the murine as well as human Prostaglandin F2 alpha MPM cells in part by increasing levels of ubiquitinated proteins. DSF-Cu exposure stimulated apoptosis in MPM cells that involved activation of stress-activated protein kinases (SAPKs) p38 and JNK1/2, caspase-3, and cleavage of poly-(ADP-ribose)-polymerase, as well as increased expression of sulfatase 1 and apoptosis transducing CARP-1/CCAR1 protein. Gene-array based analyses revealed that DSF-Cu suppressed cell growth and metastasis-promoting genes including matrix metallopeptidase 3 and 10. DSF inhibited MPM cell growth and survival by upregulating cell cycle inhibitor p27Kip1, IGFBP7, and inhibitors of NF-B such as ABIN 1 and 2 and Inhibitory B (IB) and proteins. DSF-Cu promoted Prostaglandin F2 alpha cleavage of vimentin, as well as serine-phosphorylation and lysine-63 linked ubiquitination of podoplanin. Administration of 50 mg/kg DSF-Cu by daily i.p injections inhibited growth of murine MPM cell-derived tumors studies underscore its potential as an anti-MPM agent. Introduction Malignant pleural mesothelioma (MPM) is an aggressive malignancy that is associated with past asbestos exposure. Millions of workers in the US and world over have been exposed to asbestos, and exposure to asbestos has been shown to increase the risk of several severe diseases including asbestosis, lung malignancy and MPM [1]. It is estimated that you will find 2,000 to 3,000 people diagnosed with MPM each year in the Rabbit Polyclonal to DIDO1 United States and the incidence of this disease is expected to increase in the next decade in United States and Europe [3], [4]. MPM is usually a rapidly progressing thoracic malignancy that is characterized with late metastases and poor prognosis [1]. MPM is usually highly resistant to standard therapies that consist of multimodality treatment including surgery, adjuvant or neoadjuvant chemotherapy, and radiation [2]. The median survival of MPM is about 9C17 months [3], and coupled with its increasing incidence and resistance to currently available chemotherapies, development of new treatments for MPM is usually urgently needed. Disulfiram (DSF) is usually a member of the dithiocarbamate family comprising a broad class of molecules possessing an R1R2NC(S)SR3 functional group, which gives them the ability to complex metals and react with sulfhydryl groups [5]C[7]. DSF, an irreversible inhibitor of aldehyde dehydrogenase, is one of the two drugs approved by the Food and Drug Administration (FDA) for treatment of alcoholism [7]. Clinical trials have shown efficacy of DSF with minimal to absent toxicity [7]. Several studies have shown that DSF and its metabolites can potentiate the effects of some anticancer drugs [8], [9]. Previous studies have exhibited that DSF is usually capable of binding copper and forms a new complex (DSF-Cu). A number of recent studies have further highlighted a requirement of copper in DSF-induced toxicity and radiosensitization of malignancy cells, induction of oxidative stress, and inhibition of NF-B and proteasome by DSF-Cu in a variety of malignancy cell types. However, the precise molecular mechanisms of DSF-Cu actions remain to be elucidated [10]C[13]. Here we investigated the MPM inhibitory properties of DSF-Cu and the molecular mechanisms involved. Although DSF-Cu stimulated activation of pro-apoptotic SAPKs, and caspase-9, -3, our gene-array-based analysis revealed that DSF-Cu suppressed expression of cell growth and metastasis transducers such as matrix metallopeptidase 3 and 10. Moreover, DSF-Cu suppression of MPM cell growth involved stimulation of a novel transducer of cell growth and apoptosis signaling CARP-1/CCAR1 [14]C[16]. Intra-peritoneal administration of DSF-Cu suppressed growth of murine mesothelioma allografts in part by enhancing apoptosis. Our proof-of-concept studies reveal, for the first Prostaglandin F2 alpha time, MPM inhibitory properties of DSF-Cu and are expected to facilitate utilization of this agent or its potent derivatives as potential adjuvant for treatment and perhaps chemoprevention of MPM. Materials and Methods Cells and Reagents Human MPM cell lines (H2373, H2452, H2595, H2714 and H2461) were previously established in our laboratory and characterized in detail.