Repurposing disulfiram for cancer therapy via targeted nanotechnology through enhanced tumor mass penetration and disassembly

A fibroblast activation protein α-activatable nanoagent co-delivering diethyldithiocarbamate and copper for tumor therapy and imaging

Disulfiram (DSF), an FDA-approved drug for treating alcoholism, has been verified with Cu2+-dependent anticancer activity by forming Cu(DTC)2, the complex of one of its metabolites diethyldithiocarbamate (DTC) and Cu2+. Nevertheless, the antitumor effect is limited by insufficient Cu(DTC)2 formation in suit and off-target system toxicity. Herein, we developed a fibroblast activation protein α (FAPα) activatable nanoagent (HfD-HID-Cu) for co-delivery of DTC polymeric prodrug and exogenous Cu2+ to achieve enhanced cancer-specific therapy and activatable in situ fluorescence imaging meanwhile. HfD-HID-Cu was simply constructed through the co-assembly of the DTC polymeric prodrug (HA-fap-DTC) and the copper-loaded IR808-conjugated polymer (HA-IR-DPA-Cu), which could serve as the "OFF-to-ON" switch for chemotherapy and fluorescence. With the high expression of FAPα in tumor tissues, HA-fap-DTC could be activated specifically to release DTC, while maintaining inactive in normal tissues. The liberated DTC within tumor tissues could contend for Cu2+ from HA-IR-DPA-Cu, resulting in the formation of highly cytotoxic Cu(DTC)2in situ for chemotherapy, concomitant with the fluorescence recovery of cyanine dye for tumor imaging. This work provides an effective strategy for co-delivery of DTC prodrug and Cu2+ for tumor theranostic with improved selectivity and minimal side effects. STATEMENT OF SIGNIFICANCE: DSF-based antitumor therapy is highly dependent on Cu2+. However, the non-synchronous distribution of DSF/DTC and Cu2+ in tumor tissues attenuates the antitumor efficacy. The insufficient Cu(DTC)2 formation in suit and off-target distribution greatly limit the anti-tumor application. This study provides a nanoagent for co-delivery of DTC polymeric prodrug and Cu2+ by simple co-assembly to achieve their synchronous tumor distribution. It can be selectively activated by FAPα, forming cytotoxic Cu(DTC)2in suit for tumor-specific chemotherapy and reducing the systemic toxicity. In addition to chemotherapy, the nanoagent can emit fluorescence under the sequential triggering of FAPα and released DTC for tumor imaging. Overall, this study renders a promising strategy for improved Cu(DTC)2-based antitumor therapy and imaging.

Sodium diethyldithiocarbamate trihydrate: an effective and selective compound for hematological malignancies

Myeloid leukemias and lymphomas are among the most common and well-studied hematological malignancies. However, due to the aggressiveness and rapid progression of certain subtypes, treating these diseases remains a challenge. Considering the promising results of diethyldithiocarbamates in preclinical and clinical oncology trials, this study aimed to investigate the potential of sodium diethyldithiocarbamate trihydrate (DETC) as a prototype for developing new drugs to treat hematological malignancies. In silico analysis using SwissADME was conducted to evaluate the physicochemical characteristics and pharmacokinetic properties of DETC. An in vitro investigation utilizing the MTT assay assessed the cytotoxic effects of DETC on neoplastic and non-neoplastic cell lines. Selectivity was determined using a selectivity index and a hemolysis assay, while the mechanism of cell death in neoplastic cell lines was examined through flow cytometry analysis of pro-apoptotic and anti-apoptotic protein levels. The results demonstrated that the physicochemical characteristics of DETC are suitable for oral administration. Furthermore, the compound showed promising cytotoxic activity against human myeloid leukemia (K562) and Burkitt's lymphoma (Daudi) cell lines, with high selectivity for neoplastic cells over non-neoplastic cells of the bone marrow microenvironment (HS-5 cell line). Moreover, hemolysis was observed only at very high concentrations. The cytotoxicity mechanism of DETC against both neoplastic cell lines involved cell cycle arrest and the production of reactive oxygen species. In K562 cells, cell death was induced via apoptosis. Additional experiments are needed to confirm the exact mechanism of cell death in Daudi Burkitt's lymphoma cells.

Quality-by-design-based microemulsion of disulfiram for repurposing in melanoma and breast cancer therapy

Aim: The current study aims to develop and optimize microemulsions (ME) through Quality-by-Design (QbD) approach to improve the aqueous solubility and dissolution of poorly water-soluble drug disulfiram (DSF) for repurposing in melanoma and breast cancer therapy.Materials & methods: The ME was formulated using Cinnamon oil & Tween® 80, statistically optimized using a D-optimal mixture design-based QbD approach to develop the best ME with low vesicular size (Zavg) and polydispersity index (PDI).Results: The DSF-loaded optimized stable ME showed enhanced dissolution, in-vitro cytotoxicity and improved cellular uptake in B16F10 and MCF-7 cell lines compared with their unformulated free DSF.Conclusion: Our investigations suggested the potential of the statistically designed DSF-loaded optimized ME for repurposing melanoma and breast cancer therapy.

Exploring the potential of drug repurposing for liver diseases: A comprehensive study

Drug repurposing involves the investigation of existing drugs for new indications. It offers a great opportunity to quickly identify a new drug candidate at a lower cost than novel discovery and development. Despite the importance and potential role of drug repurposing, there is no specific definition that healthcare providers and the World Health Organization credit. Unfortunately, many similar and interchangeable concepts are being used in the literature, making it difficult to collect and analyze uniform data on repurposed drugs. This research was conducted based on understanding general criteria for drug repurposing, concentrating on liver diseases. Many drugs have been investigated for their effect on liver diseases even though they were originally approved (or on their way to being approved) for other diseases. Some of the hypotheses for drug repurposing were first captured from the literature and then processed further to test the hypothesis. Recently, with the revolution in bioinformatics techniques, scientists have started to use drug libraries and computer systems that can analyze hundreds of drugs to give a short list of candidates to be analyzed pharmacologically. However, this study revealed that drug repurposing is a potential aid that may help deal with liver diseases. It provides available or under-investigated drugs that could help treat hepatitis, liver cirrhosis, Wilson disease, liver cancer, and fatty liver. However, many further studies are needed to ensure the efficacy of these drugs on a large scale.

Precision targeting of CuET overload to disrupt mitochondrial unfolded protein response by integrated liposome

Mitochondria in breast cancer play a critical role in survival and adaptation to dynamic environments. Thus, targeting mitochondria emerges as a promising therapeutic strategy for breast cancer. However, the adaptive unfolded protein response in mitochondria (UPRmt) due to mitochondrial unspecific distribution might contribute to diminished therapeutic outcomes. Herein, mitochondrial targeting liposome agents (CTPP-Lipid) are constructed and adopted for delivering the copper ion (CuET-DSF), which is especially sensitive for mitochondria-abundant breast tumors. In brief, the CTPP-Lipid@CuET achieves the goal of Cu2+ overloading by mitochondria targeting delivery. This rapidly increases ROS production, disrupts mitochondrial structure, and avoids the adaptive UPRmt formation, finally leading to apoptosis of breast cancer cells. In general, the Cu2+ overloading at mitochondria by CTPP-Lipid@CuET is a potential strategy for antitumor therapy, providing new insights into breast tumor therapy.

COVID-19 therapeutics: Clinical application of repurposed drugs and futuristic strategies for target-based drug discovery

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes the complicated disease COVID-19. Clinicians are continuously facing huge problems in the treatment of patients, as COVID-19-specific drugs are not available, hence the principle of drug repurposing serves as a one-and-only hope. Globally, the repurposing of many drugs is underway; few of them are already approved by the regulatory bodies for their clinical use and most of them are in different phases of clinical trials. Here in this review, our main aim is to discuss in detail the up-to-date information on the target-based pharmacological classification of repurposed drugs, the potential mechanism of actions, and the current clinical trial status of various drugs which are under repurposing since early 2020. At last, we briefly proposed the probable pharmacological and therapeutic drug targets that may be preferred as a futuristic drug discovery approach in the development of effective medicines.

The immunomodulatory function and antitumor effect of disulfiram: paving the way for novel cancer therapeutics

More than 60 years ago, disulfiram (DSF) was employed for the management of alcohol addiction. This promising cancer therapeutic agent inhibits proliferation, migration, and invasion of malignant tumor cells. Furthermore, divalent copper ions can enhance the antitumor effects of DSF. Molecular structure, pharmacokinetics, signaling pathways, mechanisms of action and current clinical results of DSF are summarized here. Additionally, our attention is directed towards the immunomodulatory properties of DSF and we explore novel administration methods that may address the limitations associated with antitumor treatments based on DSF. Despite the promising potential of these various delivery methods for utilizing DSF as an effective anticancer agent, further investigation is essential in order to extensively evaluate the safety and efficacy of these delivery systems.

Advancing Cancer Therapy with Copper/Disulfiram Nanomedicines and Drug Delivery Systems

Disulfiram (DSF) is a thiocarbamate based drug that has been approved for treating alcoholism for over 60 years. Preclinical studies have shown that DSF has anticancer efficacy, and its supplementation with copper (CuII) significantly potentiates the efficacy of DSF. However, the results of clinical trials have not yielded promising results. The elucidation of the anticancer mechanisms of DSF/Cu (II) will be beneficial in repurposing DSF as a new treatment for certain types of cancer. DSF's anticancer mechanism is primarily due to its generating reactive oxygen species, inhibiting aldehyde dehydrogenase (ALDH) activity inhibition, and decreasing the levels of transcriptional proteins. DSF also shows inhibitory effects in cancer cell proliferation, the self-renewal of cancer stem cells (CSCs), angiogenesis, drug resistance, and suppresses cancer cell metastasis. This review also discusses current drug delivery strategies for DSF alone diethyldithocarbamate (DDC), Cu (II) and DSF/Cu (II), and the efficacious component Diethyldithiocarbamate-copper complex (CuET).

Addressing the gaps in homeostatic mechanisms of copper and copper dithiocarbamate complexes in cancer therapy: a shift from classical platinum-drug mechanisms

The platinum drug, cisplatin, is considered as among the most successful medications in cancer treatment. However, due to its inherent toxicity and resistance limitations, research into other metal-based non-platinum anticancer medications with diverse mechanisms of action remains an active field. In this regard, copper complexes feature among non-platinum compounds which have shown promising potential as effective anticancer drugs. Moreover, the interesting discovery that cancer cells can alter their copper homeostatic processes to develop resistance to platinum-based treatments leads to suggestions that some copper compounds can indeed re-sensitize cancer cells to these drugs. In this work, we review copper and copper complexes bearing dithiocarbamate ligands which have shown promising results as anticancer agents. Dithiocarbamate ligands act as effective ionophores to convey the complexes of interest into cells thereby influencing the metal homeostatic balance and inducing apoptosis through various mechanisms. We focus on copper homeostasis in mammalian cells and on our current understanding of copper dysregulation in cancer and recent therapeutic breakthroughs using copper coordination complexes as anticancer drugs. We also discuss the molecular foundation of the mechanisms underlying their anticancer action. The opportunities that exist in research for these compounds and their potential as anticancer agents, especially when coupled with ligands such as dithiocarbamates, are also reviewed.

Trim-Away in adult animals through Nano-ERASER and its application in cancer therapy

Trim-Away is a versatile intracellular protein degradation pathway that has been extensively explored in vitro. However, the in vivo application of Trim-Away is limited at oocyte and zygote stages due to the lack of an in vivo practical approach for intracellular antibody delivery. To broaden the application of Trim-Away, especially for clinical use, we developed a nanogel-based Nano-ERASER system. Here, we demonstrated that the intracellular delivery of anti-programmed cell death ligand 1 (PD-L1) antibody through Nano-ERASER could effectively deplete PD-L1 in triple negative breast cancer (TNBC) cells and induce cancer cell death. Furthermore, with the help of a tumor tissue-targeted nanogel, anti-PD-L1 antibody-loaded Nano-ERASER effectively inhibited tumor progression in a TNBC mouse model. These results confirmed that Nano-ERASER realized Trim-Away in adult animals for the first time, which could be an effective tool for disease treatment and studying gene/protein function both in vitro and in vivo.

A Stimuli-Responsive Small-Molecule Metal-Carrying Prochelator: A Novel Prodrug Design Strategy for Metal Complexes

Selective activation of prodrugs is an important approach to reduce the side effects of disease treatment. We report a prodrug design concept for metal complexes, termed "metal-carrying prochelator", which can co-carry a metal ion and chelator within a single small-molecule compound and remain inert until it undergoes a specifically triggered intramolecular chelation to synthesize a bioactive metal complex in situ for targeted therapy. As a proof-of-concept, we designed a H₂ O₂ -responsive small-molecule prochelator, DPBD, based on the strong chelator diethyldithiocarbamate (DTC) and copper. DPBD can carry Cu²⁺ (DPBD-Cu) and respond to elevated H₂ O₂ levels in tumor cells by releasing DTC, which rapidly chelates Cu²⁺ from DPBD-Cu affording a DTC-copper complex with high cytotoxicity, realizing potent antitumor efficacy with low systemic toxicity. Thus, with its unique intramolecularly triggered activation mechanism, this concept based on a small-molecule metal-carrying prochelator can help in the prodrug design of metal complexes.

Peptide-Based Bioconjugates and Therapeutics for Targeted Anticancer Therapy

With rapidly growing knowledge in bioinformatics related to peptides and proteins, amino acid-based drug-design strategies have recently gained importance in pharmaceutics. In the past, peptide-based biomedicines were not widely used due to the associated severe physiological problems, such as low selectivity and rapid degradation in biological systems. However, various interesting peptide-based therapeutics combined with drug-delivery systems have recently emerged. Many of these candidates have been developed for anticancer therapy that requires precisely targeted effects and low toxicity. These research trends have become more diverse and complex owing to nanomedicine and antibody–drug conjugates (ADC), showing excellent therapeutic efficacy. Various newly developed peptide–drug conjugates (PDC), peptide-based nanoparticles, and prodrugs could represent a promising therapeutic strategy for patients. In this review, we provide valuable insights into rational drug design and development for future pharmaceutics.

Cytotoxic effect of disulfiram/copper on human cervical cancer cell lines and LGR5-positive cancer stem-like cells

BACKGROUND

Tumor resistance is a global challenge for tumor treatment. Cancer stem cells (CSCs) are the main population of tumor cells for drug resistance. We have reported that high aldehyde dehydrogenase (ALDH) activity represents a functional marker for cervical CSCs. Here, we aimed at disulfiram (DSF), an ALDH inhibitor, that has the potential to be used for cervical cancer treatment.

METHODS

MTT assay, western blot, vector construction and transfection, cell sorting and in vivo anti-tumor assays were performed using cervical cancer cell lines SiHa and HeLa. Cell cycle distribution and cell apoptosis were carried out by flow cytometry. The cytotoxicity of DSF was detected by MTT assay and cervical cancer xenograft models.

RESULTS

DSF was cytotoxic to cervical cancer cell lines in a copper (Cu)-dependent manner. Disulfiram/copper (DSF/Cu) complex induced deregulation of S-phase and inhibited the expression of stemness markers in cervical cancer cells. Furthermore, DSF/Cu could also reduce the cancer stem cell-like LGR5⁺ cells which lead to cisplatin resistance in cervical cancer cells. DSF/Cu complex had the greater antitumor efficacy on cervical cancer than cisplatin in vitro and in vivo.

CONCLUSION

Our findings indicate that the cytotoxicity of DSF/Cu complex may be superior to cisplatin because of targeting LGR5-positive cervical cancer stem-like cells in cervical cancer. Thus, the DSF/Cu complex may represent a potential therapeutic strategy for cervical cancer patients.

Selective Targeting of Cancer Cells by Copper Ionophores: An Overview

Conventional cancer therapies suffer from severe off-target effects because most of them target critical facets of cells that are generally shared by all rapidly proliferating cells. The development of new therapeutic agents should aim to increase selectivity and therefore reduce side effects. In addition, these agents should overcome cancer cell resistance and target cancer stem cells. Some copper ionophores have shown promise in this direction thanks to an intrinsic selectivity in preferentially inducing cuproptosis of cancer cells compared to normal cells. Here, Cu ionophores are discussed with a focus on selectivity towards cancer cells and on the mechanisms responsible for this selectivity. The proposed strategies, to further improve the targeting of cancer cells by copper ionophores, are also reported.

Two birds with one stone: Copper metal-organic framework as a carrier of disulfiram prodrug for cancer therapy

Disulfiram (DSF) has a copper (II)-potentiated anticancer activity in various cancers. Synchronous delivery of DSF and cupric ions to tumor tissues is challenging but holds great potential in improving antitumor outcomes and promoting clinical translation. Herein, we reported a disulfiram prodrug (DQ)-loaded and glucose oxidase (GOD) conjugated copper (II)-based nanoscale metal-organic framework (MOF), MPDG, for tumor-specific, enhanced chemo-chemodynamic therapy. Copper MOF, MOF-199, played a dual role of drug nanocarrier of DQ and copper ion reservoir for sufficient generation of copper (II) diethylthiocarbamate (Cu(DTC)₂), a complex of DSF and Cu²⁺. GOD improved the stability of Cu(II) nano-depot and enabled catalytic generation of H₂O₂ in response to high concentration of glucose in cancer cells. The catalytically generating and endogenous H₂O₂ boosted the activation of encapsulated H₂O₂-activatable prodrug DQ to generate highly cytotoxic Cu(CDTC)₂ in situ for tumor-specific chemotherapy. Meanwhile, the elevated H₂O₂ significantly augmented the production of OH for enhanced chemodynamic therapy. The self-activated amplified chemo-chemodynamic therapy nanosystem led to a significantly enhanced inhibition of 4T1 murine breast cancer cells (half inhibitory concentration reduced from 5 μg/mL to 0.8 μg/mL) in the presence of glucose. The in vivo study verified that MPDG showed the highest tumor inhibition rate of 86.2% and negligible toxicity to main organs. Overall, this study provides a novel disulfiram prodrug/Cu²⁺ co-delivery strategy for enhanced and selective cancer treatment.

Copper (Ⅱ)/cis-platinum -loaded nanogels as an adjuvant potentiate disulfiram antitumor efficacy

Disulfiram (DSF) is nontoxic and exerts anticancer activity by forming highly toxic chelate via its metabolite diethyldithiocarbamate with transition metal ions. However, there are not enough such ions in the...

Leveraging disulfiram to treat cancer: Mechanisms of action, delivery strategies, and treatment regimens

Disulfiram (DSF) has been used as an alcoholism drug for 70 years. Recently, it has attracted increasing attention owing to the distinguished anticancer activity, which can be further potentiated by the supplementation of Cu²⁺. Although encouraging anticancer results are obtained in lab, the clinical outcomes of oral DSF are not satisfactory, which urges an in-depth understanding of the underlying mechanisms, bottlenecks, and proposal of potential methods to address the dilemma. In this review, a critical summarization of various molecular biological anticancer mechanisms of DSF/Cu²⁺ is provided and the predicament of orally delivering DSF in clinical oncotherapy is explained by the metabolic barriers. We highlight the recent advances in the DSF/Cu²⁺ delivery strategies and the emerging treatment regimens for cancer treatment. Last but not the least, we summarize the clinical trials regarding DSF and make a prospect of DSF/Cu-based cancer therapy.

Disulfiram inhibits IL-1β secretion and inflammatory cells recruitment in Aspergillus fumigatus keratitis

PURPOSE

Disulfiram, an inhibitor of gasdermin D-induced pore formation, is known to suppress interleukin (IL)-1β secretion and pyroptosis. However, its effects on fungal keratitis remain unknown. Therefore, we investigated the role of disulfiram in Aspergillus fumigatus keratitis.

METHODS

In vitro, Cell Count Kit-8 (CCK8) assay and cell scratch test were performed to determine optimal concentration. In vivo and in vitro experiments were conducted in a mouse model, human neutrophils, and mouse peritoneal macrophages. We pre-treated the mice or cells with disulfiram and infected them with A. fumigatus at specific times. We subsequently evaluated the development of fungal keratitis lesions, the recruitment of inflammatory cells, and the production of inflammatory cytokines using slit lamp microscopy, clinical evaluation, quantitative reverse transcription polymerase chain reaction, immunofluorescence staining, enzyme-linked immunosorbent assay, and western blotting. We also used slit lamp microscopy and clinical evaluation to assess the effect of natamycin with or without disulfiram.

RESULTS

Disulfiram at 20 μM has no significant cytotoxic effect and does not affect cell migration. In the mouse model, disulfiram significantly suppressed inflammatory responses, reduced neutrophil and macrophage recruitment, and down-regulated myeloperoxidase and nitric oxide synthase levels at earlier stages of infection. Disulfiram had no effect on IL-1β production and maturation, but it inhibited IL-1β secretion in macrophages. Disulfiram combined with natamycin significantly increased corneal transparency in the mice model.

CONCLUSION

Overall, disulfiram reduced the host immune response in fungal keratitis by attenuating neutrophil and macrophage recruitment and inhibiting IL-1β secretion in macrophages. Disulfiram in combination with antifungal agents may serve as a novel therapeutic method for reducing corneal opacity in fungal keratitis.

Esterase-activatable and GSH-responsive Triptolide Nano-prodrug for the Eradication of Pancreatic Cancer

Triptolide (TPL) is a small molecule isolated from a traditional Chinese herb Tripterygium wilfordii Hook F and shows excellent anticancer effect for pancreatic cancer cells. However, the poor water solubility and severe liver toxicity of TPL hindered its clinical application. In this study, TPL was covalently conjugated to a polymer and entrapped inside the core of the TPL nanogel (nTPL) to protect it from premature leakage during blood circulation. With the help of lactobionic acid (LBA), nTPL-LBA could selectively target the tumors in an orthotopic pancreatic cancer mouse model. TPL could be subsequently released intracellularly in its original form due to the presence of elevated intracellular esterase and GSH, and eventually kills cancer cells. nTPL-LBA treatment reduced tumor burden by 99% while not introducing TPL associated liver and kidney toxicities. Most importantly, more than half of the nTPL-LBA treated animals were tumor-free, suggesting that nTPL-LBA is an effective approach in eradicating pancreatic cancer.

Glutathione-responsive copper-disulfiram nanoparticles for enhanced tumor chemotherapy

Disulfiram (DSF), a familiar FDA-approved drug used for alcohol withdrawal, has recently been verified with potent antitumor therapeutic effect by generating Cu(DTC)₂, which is the complex of its metabolite diethyldithiocarbamate (DTC) and copper. However, its poor tumor selectivity and insufficient endogenous Cu²⁺ concentration within tumor site largely hinders the application of DSF-based antitumor therapy. Therefore, a GSH-responsive coordination nanoparticles (Cu-IXZ@DSF) was established as a copper carrier to achieve synchronous but separate delivery of Cu²⁺ and DSF without antitumor ability, further to realize selectively triggered tumor in situ Cu(DTC)₂ generation for antitumor therapy. A widely-used proteasome inhibitor ixazomib (IXZ) was chosen as ligands and Cu²⁺ was used as coordination nodes to form nanosized Cu-IXZ@DSF. The DSF encapsulated in Cu-IXZ@DSF could be reduced to DTC by intracellular GSH, which could contend for Cu²⁺ and realize in situ high toxic Cu(DTC)₂ generation. Meanwhile, the chelation could lead to the disassembly of Cu-IXZ@DSF and release of IXZ to eventually achieve tumor specific "transformation from low toxicity to high toxicity" chemotherapy. The results of in vitro and in vivo experiments demonstrated that the as-prepared nanoplatform Cu-IXZ@DSF showed good biosafety and excellent antitumor effect via endoplasmic reticulum stress (ERS) as well as reactive oxygen species (ROS) generation pathway. Therefore, this nanocarrier provides an inspiring strategy with specific-triggered antitumor Cu(DTC)₂ generation for DSF-based chemotherapy with high therapeutic effect and biosafety and showing great potential of treating cancer.

Repurposing Disulfiram for Targeting of Glioblastoma Stem Cells: An In Vitro Study

Mesenchymal glioblastoma stem cells (GSCs), a subpopulation in glioblastoma that are responsible for therapy resistance and tumor spreading in the brain, reportedly upregulate aldehyde dehydrogenase isoform-1A3 (ALDH1A3) which can be inhibited by disulfiram (DSF), an FDA-approved drug formerly prescribed in alcohol use disorder. Reportedly, DSF in combination with Cu2+ ions exerts multiple tumoricidal, chemo- and radio-therapy-sensitizing effects in several tumor entities. The present study aimed to quantify these DSF effects in glioblastoma stem cells in vitro, regarding dependence on ALDH1A3 expression. To this end, two patient-derived GSC cultures with differing ALDH1A3 expression were pretreated (in the presence of CuSO4, 100 nM) with DSF (0 or 100 nM) and the DNA-alkylating agent temozolomide (0 or 30 µM) and then cells were irradiated with a single dose of 0-8 Gy. As read-outs, cell cycle distribution and clonogenic survival were determined by flow cytometry and limited dilution assay, respectively. As a result, DSF modulated cell cycle distribution in both GSC cultures and dramatically decreased clonogenic survival independently of ALDH1A3 expression. This effect was additive to the impairment of clonogenic survival by radiation, but not associated with radiosensitization. Of note, cotreatment with temozolomide blunted the DSF inhibition of clonogenic survival. In conclusion, DSF targets GSCs independent of ALDH1A3 expression, suggesting a therapeutic efficacy also in glioblastomas with low mesenchymal GSC populations. As temozolomide somehow antagonized the DSF effects, strategies for future combination of DSF with the adjuvant standard therapy (fractionated radiotherapy and concomitant temozolomide chemotherapy followed by temozolomide maintenance therapy) are not supported by the present study.

Nanogel-facilitated Protein Intracellular Specific Degradation through Trim-Away

Recently discovered "Trim-Away" mechanism opens a new window for fast and selective degradation of endogenous proteins. However, the in vivo and clinical application of this approach is stuck by the requirement of special skills and equipment needed for the intracellular delivery of antibodies. Hereby, an antibody conjugated polymer nanogel system, Nano-ERASER, for intracellular delivery and release of antibody, and degradation of a specific endogenous protein has been developed. After being delivered into cells, the antibody is released and forms complex with its target protein, and subsequently binds to the Fc receptor of TRIM21. The resulted complex of target protein/antibody/TRIM21 is then degraded by the proteasome. The efficacy of Nano-ERASER has been validated by depleting GFP protein in a GFP expressing cell line. Furthermore, Nano-ERASER successfully degrades COPZ1, a vital protein for cancer cells, and kills those cells while sparing normal cells. Benefit from its convenience and targeted delivery merit, Nano-ERASER technique is promising in providing a reliable tool for endogenous protein function study as well as paves the way for novel antibody-based Trim-Away therapeutic modalities for cancer and other diseases.

In situ triggering antitumor efficacy of alcohol-abuse drug disulfiram through Cu-based metal-organic framework nanoparticles

Although approved as an alcohol-abuse drug, disulfiram (DSF) exhibited potential anticancer activity when chelated with copper (Cu). However, the low level of intrinsic Cu, toxicity originated from exogenous Cu supplementation, and poor stability of DSF in vivo severely limited its application in cancer treatment. Herein, we proposed an in situ DSF antitumor efficacy triggered system, taking advantages of Cu-based metal-organic framework (MOF). In detail, DSF was encapsulated into Cu-MOF nanoparticles (NPs) during its formation, and the obtained NPs were coated with hyaluronic acid to enhance the tumor targetability and biocompatibility. Notably, DSF loaded Cu-MOF NPs maintained stability and integrity without Cu2+ leakage in blood circulation, thus showing excellent biosafety. Once accumulating at tumor site, NPs were internalized into tumor cells via receptor-mediated endocytosis and released DSF and Cu2+ simultaneously in the hyaluronidase-enriched and acidic intracellular tumor microenvironment. This profile lead to in situ chelation reaction between DSF and Cu2+, generating toxic DSF/Cu complex against tumor cells. Both in vitro and in vivo results demonstrated the programmed degradation and recombination property of Cu-based MOF NPs, which facilitated the tumor-specific chemotherapeutic effects of DSF. This system provided a promising strategy for the application of DSF in tumor therapy.

Pharmaceutical strategies in improving anti-tumour efficacy and safety of intraperitoneal therapy for peritoneal metastasis

Introduction: In selected patients with limited peritoneal metastasis (PM), favorable tumor biology, and a good clinical condition, there is an indication for combination of cytoreductive surgery (CRS) and subsequent intravenous (IV) or intraperitoneal (IP) chemotherapy. Compared with IV injection, IP therapy can achieve a high drug concentration within the peritoneal cavity with low systemic toxicity, however, the clinical application of IP chemotherapy is limited by the related abdominal pain, infection, and intolerance.Areas covered:To improve the anti-tumor efficacy and safety of IP therapy, various pharmaceutical strategies have been developed and show promising potential. This review discusses the specialized modification of traditional drug delivery systems and demonstrates the preparation of customized drug carriers for IP therapy, including chemotherapy and gene therapy. IP therapy has important clinical significance in the treatment of PM using novel anti-tumor agents as well as conventional drugs in new applications.Expert opinion: Although IP therapy exhibits good performance both in mouse models and in patients with PM in clinical trials, its clinical application remains limited due to the serious side effects and low acceptability. Further investigations, including pharmaceutical strategies, are needed to develop potential IP therapy, focusing on the efficacy and safety thereof.

Nanomedicine for Gene Delivery and Drug Repurposing in the Treatment of Muscular Dystrophies

Muscular Dystrophies (MDs) are a group of rare inherited genetic muscular pathologies encompassing a variety of clinical phenotypes, gene mutations and mechanisms of disease. MDs undergo progressive skeletal muscle degeneration causing severe health problems that lead to poor life quality, disability and premature death. There are no available therapies to counteract the causes of these diseases and conventional treatments are administered only to mitigate symptoms. Recent understanding on the pathogenetic mechanisms allowed the development of novel therapeutic strategies based on gene therapy, genome editing CRISPR/Cas9 and drug repurposing approaches. Despite the therapeutic potential of these treatments, once the actives are administered, their instability, susceptibility to degradation and toxicity limit their applications. In this frame, the design of delivery strategies based on nanomedicines holds great promise for MD treatments. This review focuses on nanomedicine approaches able to encapsulate therapeutic agents such as small chemical molecules and oligonucleotides to target the most common MDs such as Duchenne Muscular Dystrophy and the Myotonic Dystrophies. The challenge related to in vitro and in vivo testing of nanosystems in appropriate animal models is also addressed. Finally, the most promising nanomedicine-based strategies are highlighted and a critical view in future developments of nanomedicine for neuromuscular diseases is provided.

Disulfiram: a novel repurposed drug for cancer therapy

Cancer is a major health issue worldwide and the global burden of cancer is expected to reduce the costs of treatment as well as prolong the survival time. One of the promising approaches is drug repurposing, because it reduces costs and shortens the production cycle of research and development. Disulfiram (DSF), which was originally approved as an anti-alcoholism drug, has been proven safe and shows the potential to target tumours. Its anti-tumour effect has been reported in many preclinical studies and recently on seven types of cancer in humans: non-small cell lung cancer (NSCLC), liver cancer, breast cancer, prostate cancer, pancreatic cancer, glioblastoma (GBM) and melanoma and has a successful breakthrough in the treatment of NSCLC and GBM. The mechanisms, particularly the intracellular signalling pathways, still remain to be completely elucidated. As shown in our previous study, DSF inhibits NF-kB signalling, proteasome activity, and aldehyde dehydrogenase (ALDH) activity. It induces endoplasmic reticulum (ER) stress and autophagy and has been used as an adjuvant therapy with irradiation or chemotherapy drugs. On the other hand, DSF not only kills the normal cancer cells but also has the ability to target cancer stem cells, which provides a new approach to prevent tumour recurrence and metastasis. Furthermore, other researchers have reported the ability of DSF to bind to nuclear protein localization protein 4 (NPL4), induce its immobilization and dysfunction, ultimately leading to cell death. Here, we provide an overview of DSF repurposing as a treatment in preclinical studies and clinical trials, and review studies describing the mechanisms underlying its anti-neoplastic effects.

Biodegradable Quantum Composites for Synergistic Photothermal Therapy and Copper-Enhanced Chemotherapy

In recent times, the combination therapy has garnered enormous interest owing to its great potential in clinical research. It has been reported that disulfiram, a clinical antialcoholism drug, could be degraded to diethyldithiocarbamate (DDTC) in vivo and subsequently result in the copper-DDTC complex (Cu(DDTC)₂) toward ablating cancer cells. In addition, the ultrasmall copper sulfide nanodots (CuS NDs) have shown great potential in cancer treatment because of their excellent photothermal and photodynamic therapeutic efficiencies. Herein, by taking advantage of the interactions between CuS and DDTC, a new multifunctional nanoplatform based on DDTC-loaded CuS (CuS-DDTC) NDs is successfully fabricated, leading to the achievement of the synergistic effect of photothermal and copper enhanced chemotherapy. All experimental results verified promising synergistic therapeutic effects. Moreover, in vivo biocompatibility and metabolism experiments displayed that the CuS-DDTC NDs could be quickly excreted from the body with no apparent toxicity signs. Together, our findings indicated the superior synergistic therapeutic effect of photothermal and copper-enhanced chemotherapy, providing a promising anticancer strategy based on the CuS-DDTC NDs drug delivery system.

Utilizing drug repurposing against COVID-19 - Efficacy, limitations, and challenges

The recent outbreak of Coronavirus disease (COVID-19), first in Eastern Asia and then essentially across the world has been declared a pandemic by the WHO. COVID-19 is caused by a novel virus SARS-CoV2 (2019-nCoV), against which there is currently no vaccine available; and current antiviral therapies have failed, causing a very high mortality rate. Drug repurposing i.e. utilizing an approved drug for different indication, offers a time- and cost-efficient alternative for making new therapies available to patients. Although there are several reports presenting novel approaches to treat COVID-19, still an attentive review of previous scientific literature is essential to overcome their failure to exhibit efficacy. There is an urgent need to provide a comprehensive outlook toward utilizing drug repurposing as a tool for discovery of new therapies against COVID-19. In this article, we aim to provide a to-the-point review of current literature regarding efficacy of repurposed drugs against COVID-19 and other respiratory infections caused by coronaviruses. We have briefly discussed COVID-19 epidemiology, and then have discussed drug repurposing approaches and examples, specific to respiratory viruses. Limitations of utilization of repurposed drug molecules such as dosage regimen and associated challenges such as localized delivery in respiratory tract have also been discussed in detail.

Redox-Sensitive Nanocomplex for Targeted Delivery of Melittin

Although peptide therapeutics have been explored for decades, the successful delivery of potent peptides in vitro and in vivo remains challenging due to the poor stability, low cell permeability, and off-target effects. We developed a redox sensitive polymer-based nanocomplex which can efficiently and stably deliver the peptide drug melittin for cancer therapy. The nanocomplex selectively targets cancer cells through lactobionic acid mediated endocytosis and releases melittin intracellularly upon the trigger of elevated redox potential. In vivo study proved that the targeted nanocomplex shows excellent potency in inhibiting tumor growth in a xenograft colon cancer mouse model. Thus, the polymer/melittin nanocomplexes will provide a new approach for melittin based cancer therapy.

Comparative Nanofabrication of PLGA-Chitosan-PEG Systems Employing Microfluidics and Emulsification Solvent Evaporation Techniques

Poor circulation stability and inadequate cell membrane penetration are significant impediments in the implementation of nanocarriers as delivery systems for therapeutic agents with low bioavailability. This research discusses the fabrication of a biocompatible poly(lactide-co-glycolide) (PLGA) based nanocarrier with cationic and hydrophilic surface properties provided by natural polymer chitosan and coating polymer polyethylene glycol (PEG) for the entrapment of the hydrophobic drug disulfiram. The traditional emulsification solvent evaporation method was compared to a microfluidics-based method of fabrication, with the optimisation of the parameters for each method, and the PEGylation densities on the experimental nanoparticle formulations were varied. The size and surface properties of the intermediates and products were characterised and compared by dynamic light scattering, scanning electron microscopy and X-ray diffraction, while the thermal properties were investigated using thermogravimetric analysis and differential scanning calorimetry. Results showed optimal particle properties with an intermediate PEG density and a positive surface charge for greater biocompatibility, with nanoparticle surface characteristics shielding physical interaction of the entrapped drug with the exterior. The formulations prepared using the microfluidic method displayed superior surface charge, entrapment and drug release properties. The final system shows potential as a component of a biocompatible nanocarrier for poorly soluble drugs.

The anti-alcohol dependency drug disulfiram inhibits the viability and progression of gastric cancer cells by regulating the Wnt and NF-κB pathways

OBJECTIVE

Disulfiram is commonly used for alcohol abuse; however, recent studies have revealed its potential as an anti-cancer treatment. This study investigated the effects of disulfiram on gastric cancer and its underlying mechanisms of action.

METHODS

The gastric cancer cell lines MKN-45 and SGC-7901 were used for all experiments. Cell proliferation was investigated using cell counting kit-8, cell migration and invasion were examined using Transwell assays, the proliferation and metastasis related proteins PCNA and MMP-2, respectively, were detected by ELISA. To explore the underlying molecular mechanisms, we also examined levels of proteins involved in the Wnt and NF-κB pathways by ELISA.

RESULTS

Disulfiram significantly inhibited the proliferation, migration, and invasion of gastric cancer cells and decreased PCNA and MMP-2 levels. Additionally, disulfiram-treated MKN-45 and SGC-7901 cells showed reduced expression of Wnt, β-catenin, and NF-κB.

CONCLUSION

Disulfiram regulates the Wnt and NF-κB pathways, and thus could be a potential treatment for managing gastric cancer.

Designer Self-Assembling Peptide Hydrogels to Engineer 3D Cell Microenvironments for Cell Constructs Formation and Precise Oncology Remodeling in Ovarian Cancer

Designer self-assembling peptides form the entangled nanofiber networks in hydrogels by ionic-complementary self-assembly. This type of hydrogel has realistic biological and physiochemical properties to serve as biomimetic extracellular matrix (ECM) for biomedical applications. The advantages and benefits are distinct from natural hydrogels and other synthetic or semisynthetic hydrogels. Designer peptides provide diverse alternatives of main building blocks to form various functional nanostructures. The entangled nanofiber networks permit essential compositional complexity and heterogeneity of engineering cell microenvironments in comparison with other hydrogels, which may reconstruct the tumor microenvironments (TMEs) in 3D cell cultures and tissue-specific modeling in vitro. Either ovarian cancer progression or recurrence and relapse are involved in the multifaceted TMEs in addition to mesothelial cells, fibroblasts, endothelial cells, pericytes, immune cells, adipocytes, and the ECM. Based on the progress in common hydrogel products, this work focuses on the diverse designer self-assembling peptide hydrogels for instructive cell constructs in tissue-specific modeling and the precise oncology remodeling for ovarian cancer, which are issued by several research aspects in a 3D context. The advantages and significance of designer peptide hydrogels are discussed, and some common approaches and coming challenges are also addressed in current complex tumor diseases.

N-Oxide polymer-cupric ion nanogels potentiate disulfiram for cancer therapy

Disulfiram (DSF) exerts potent anticancer activity via the formation of chelates with copper or zinc ions in tumor tissues, but the low abundance of these ions in the tumor cannot sustain its antitumor activity. Herein, we show that a zwitterionic water-soluble N-oxide polymer, poly[2-(N-oxide-N,N-dimethylamino)ethyl methacrylate] (OPDMA), can complex cupric ions and form nanogels (OPDMA/Cu), which efficiently deliver copper ions to tumor tissue to potentiate DSF significantly for effective antitumor therapy.

Doxorubicin intercalated copper diethyldithiocarbamate functionalized layered double hydroxide hybrid nanoparticles for targeted therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the deadliest cancers due to its long incubation period and low cure rate. Layered double hydroxide (LDH) nanoparticles have attracted considerable research interest in the field of nanomedicine owing to their surface effects and good biocompatibility. In this research, we synthesized a hexagonal nanoparticle by the co-precipitation method, referred to as Cu-Al LDH. As an alternative to traditional drug-loading methods, sodium diethyldithiocarbamate (DDC) was introduced and combined with Cu²⁺ in LDHs to form a diethyldithiocarbamate-copper complex (Cu(DDC)₂), which was not only the composition of carrier materials but also an effective component for cancer therapy. Doxorubicin (DOX) was also encapsulated into LDHs due to the clinical relevance of DOX treatment for HCC. Formulations of the Cu(DDC)₂ and DOX co-loaded nanoparticles were optimized to precisely control the Cu(DDC)₂/DOX ratio. The nanoparticles were coated with polyethylene glycol-graft-polyglutamic acid (PEG-PLG) through electrostatic adsorption to improve the stability of the nanoparticles. The outer layer was decorated with hyaluronic acid (HA) to achieve specific targeting of tumors. Compared with non-HA coated nanoparticles, HA coated nanoparticles showed greater cellular uptake in Hep G2 cells, which could cause higher cytotoxicity. In addition, targeted nanoparticles effectively inhibited tumor growth in mouse models of ectopic hepatocellular carcinoma. It can be concluded that there is a great potential for synergistic cancer therapy using the novel DOX intercalated Cu(DDC)₂ functionalized layered double hydroxide hybrid nanoparticles.

Old wine in new bottles: Advanced drug delivery systems for disulfiram-based cancer therapy

Disulfiram (DSF) is an FDA-approved drug that has been repurposed for cancer treatment. It showed excellent anticancer efficacy in combination with copper ions (Cu). Several active clinical trials testing the anticancer efficacy of DSF against various cancers are underway. In this review article, we summarized different delivery strategies for DSF-based cancer therapy. In many studies, DSF and Cu were delivered in two separate formulations. DSF and Cu formed copper diethyldithiocarbamate [Cu(DDC)₂] complex which was reported as a major active anticancer ingredient for DSF/Cu combination therapy. Various delivery systems for DSF and Cu were developed to enhance their delivery into tumors. The administration of preformed Cu(DDC)₂ complex was also explored to achieve better anticancer efficacy. Several studies developed formulations that were capable of delivering Cu(DDC)₂ complex in a single formulation. These novel formulations will address drug delivery challenges and have great potential to improve the efficacy of DSF-based cancer therapy. DSF is an off-patent drug molecule. The novel drug formulations of DSF will also serve as a good strategy for developing intellectual properties which will be critical for product development and commercialization.

Heterotargeted Nanococktail with Traceless Linkers for Eradicating Cancer

Clinical application of drug cocktails for cancer therapy is limited by their severe systemic toxicity. To solve a catch-22 dilemma between safety and efficacy for drug cocktails, a hetero-targeted nano-cocktail (PPPDMA) with traceless linkers has been developed. In the PPPDMA nanogel, a hetero-targeting strategy is employed to improve its tumor selective targeting efficacy by overcoming the cancer cell mono-ligand density limitation. Benefit from its glutathione and reactive oxygen species responsiveness, the loaded paclitaxel and doxorubicin can be quickly and tracelessly released into the cytoplasm in their original form, which bestows PPPDMA nanogels the capability to overwhelm the processing capacity of cancer cell's P-glycoprotein efflux pump allows, and ultimately kill them without inducing side effects. The PPPDMA treatment reduced its tumor burden over 99% (in tumor weight) and 96% (in tumor number). Most importantly, no detectable tumor in more than half of the PPPDMA treated mice. We conclude that traceless linker and hetero-targeted nano-cocktail strategy could be a safe and effective approach for cancer treatment.

Recent advances in the delivery of disulfiram: a critical analysis of promising approaches to improve its pharmacokinetic profile and anticancer efficacy

BACKGROUND

Disulfiram (DSF) has a long history of being used as a first-line promising therapy for treatment of alcoholism in human. Besides its prominence in the treatment of alcoholism, extensive investigations have been carried out to explore other biomedical and pharmacological effects of DSF. Amongst other biomedical implications, plenty researches have shown evidence of promising anticancer efficacy of this agent for treatment of wide range of cancers such as breast cancer, liver cancer and lung carcinoma.

METHODS

Electronic databases, including Google scholar, PubMed and Web of science were searched with the keywords disulfiram, nanoparticles, cancer, drug delivery systems.

RESULT

Despite its excellent anticancer efficacy, the pharmaceutical significance and clinical applicability of DSF are hampered due to poor stability, low solubility, short plasma half-life, rapid metabolism, and early clearance from systemic circulation. Various attempts have been made to eradicate these issues. Nanotechnology based interventions have gained remarkable recognition in improving pharmacokinetic and pharmacodynamic profile of DSF by improving its stability and avoiding its degradation.

CONCLUSION

The aim of the present review is to critically analyse all recent developments in designing various nanotechnology-based delivery systems, to ponder their relevance in improving stability, pharmacokinetic and pharmacodynamic profile, and achieving target-specific delivery of this agent to cancer cells to effectively eradicate cancer and abolish its metastasis. Nanotechnology is a novel approach for overcoming such obstacles faced presently, the results obtained so far using different novel drug delivery systems seem to be very promising to increase the stability and half-life of DSF. Graphical abstract Nanocrrier mediated drug delivery systems for disulfiram.

Chitosan for gene delivery: Methods for improvement and applications

Gene therapy is a promising strategy for treating challenging diseases. The successful delivery of genes is a critical step for gene therapy. However, concerns about immunogenicity and toxicity are the main obstacles against the widespread use of effective viral systems. Therefore, nonviral vectors are regarded as good alternatives to viral vectors. Chitosan is a natural cationic polysaccharide that could be used to create nonviral gene delivery vectors. Various methods have been developed to improve the properties of chitosan related to gene delivery. This review introduces the features of chitosan in gene delivery, summarizes current progress toward methods promoting the properties of chitosan related to gene delivery, and presents different applications of chitosan in gene delivery vectors. Finally, future prospects of gene vectors based on chitosan are discussed.

Human Endogenous Formaldehyde as an Anticancer Metabolite: Its Oxidation Downregulation May Be a Means of Improving Therapy

Malignant cells are characterized by an increased content of endogenous formaldehyde formed as a by-product of biosynthetic processes. Accumulation of formaldehyde in cancer cells is combined with activation of the processes of cellular formaldehyde clearance. These mechanisms include increased ALDH and suppressed ADH5/FDH activity, which oncologists consider poor and favorable prognostic markers, respectively. Here, the sources and regulation of formaldehyde metabolism in cancer cells are reviewed. The authors also analyze the participation of oncoproteins such as fibulins, FGFR1, HER2/neu, FBI-1, and MUC1-C in the control of genes related to formaldehyde metabolism, suggesting the existence of two mutually exclusive processes in cancer cells: 1) production and 2) oxidation and elimination of formaldehyde from the cell. The authors hypothesize that the study of the anticancer properties of disulfiram and alpha lipoic acid - which affect the balance of formaldehyde in the body - may serve as the basis of future anticancer therapy.

Investigation of the key chemical structures involved in the anticancer activity of disulfiram in A549 non-small cell lung cancer cell line

Background

Disulfiram (DS), an antialcoholism medicine, demonstrated strong anticancer activity in the laboratory but did not show promising results in clinical trials. The anticancer activity of DS is copper dependent. The reaction of DS and copper generates reactive oxygen species (ROS). After oral administration in the clinic, DS is enriched and quickly metabolised in the liver. The associated change of chemical structure may make the metabolites of DS lose its copper-chelating ability and disable their anticancer activity. The anticancer chemical structure of DS is still largely unknown. Elucidation of the relationship between the key chemical structure of DS and its anticancer activity will enable us to modify DS and speed its translation into cancer therapeutics.

Methods

The cytotoxicity, extracellular ROS activity, apoptotic effect of DS, DDC and their analogues on cancer cells and cancer stem cells were examined in vitro by MTT assay, western blot, extracellular ROS assay and sphere-reforming assay.

Results

Intact thiol groups are essential for the in vitro cytotoxicity of DS. S-methylated diethyldithiocarbamate (S-Me-DDC), one of the major metabolites of DS in liver, completely lost its in vitro anticancer activity. In vitro cytotoxicity of DS was also abolished when its thiuram structure was destroyed. In contrast, modification of the ethyl groups in DS had no significant influence on its anticancer activity.

Conclusions

The thiol groups and thiuram structure are indispensable for the anticancer activity of DS. The liver enrichment and metabolism may be the major obstruction for application of DS in cancer treatment. A delivery system to protect the thiol groups and development of novel soluble copper-DDC compound may pave the path for translation of DS into cancer therapeutics.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4617-x) contains supplementary material, which is available to authorized users.