In vitro and in vivo investigation of the anticancer activity and mechanism of disulfiram in malignant mesothelioma

Background Malignant Mesothelioma (MM) represents an asbestos-related insidious and invasive neoplasm with a long latency period. MM carries a dismal prognosis as most patients have irresectable disease or are ineligible for surgery due to medical comorbidities or old age, leaving chemotherapy and immunotherapy as standard options. Most often, the patients develop drug resistance due to the hypoxic tumour microenvironment (TME) that promotes the survival of chemo-resistant cancer stem cells (CSCs), leading to tumour infiltration and relapse. Drug repurposing has proven beneficial for rare orphan diseases like MM, leveraging established pharmacology and safety profiles to expedite patient access at a lower cost. Disulfiram (DSF), a Dithiocarbamate-based drug used for the treatment of alcoholism, has shown potential anticancer effects in combination with metal ions (Cu, Zn), primarily due to its ability to generate reactive oxygen species (ROS), inhibit aldehyde dehydrogenase (ALDH) activity, and disrupt the self-renewal of CSCs. While promising outcomes have been demonstrated in vitro, the clinical translation is hindered by the metabolic activity of DSF, limiting its systemic bioavailability. Also, MM, with its infiltrative growth pattern, is particularly resistant to conventional systemic therapy. To overcome these challenges, DSF was encapsulated in poly(lactic-co-glycolic acid) (PLGA), a biodegradable polymer, enabling local administration for sustained release and enhanced drug exposure to infiltrative tumour regions. This approach offers a promising strategy for targeted MM treatment. Aim of the Study This study aimed to investigate the anticancer activity encapsulated in PLGA microparticles in MM. Results PLGA-DSF has been successfully scaled up in an industrial setting, producing certified nanoparticles with a size of 1μm and an 18% drug loading capacity. These nanoparticles demonstrated a sustained release of DSF for up to six days without aggregation. Notably, PLGA-DSF+Cu exhibited significant cytotoxicity (IC50<500 nM) across a range of MM cell lines, including normoxic, hypoxic, spheroid-cultured, and patient-derived MM cells. Additionally, PLGA-DSF+Cu enhanced the efficacy of pemetrexed and cisplatin by calculating the Combination Index. Beyond its cytotoxic effects, PLGA-DSF+Cu inhibited key hypoxia-induced chemoresistance mechanisms, including the expression of CSC markers, sphere reformation and migration in a cell–type–dependent manner. In MM xenograft models, treatment with intraperitoneal PLGA-DSF (15 mg/kg) combined with oral Cu-Gluconate (4 mg/kg), administered twice weekly for three weeks, significantly reduced tumour burden and the number of tumour nodules compared to controls. Importantly, treated animals exhibited no adverse effects or toxicity to vital organs. RNA sequencing of PLGA-DSF-treated MM cells revealed a substantial upregulation of heat shock proteins (HSPs) and the MYC/MAD/MAX transcription factor MXD1, as well as a downregulation of NEURL1B. Further validation of these potential targets is currently underway. Significance of the Study These findings highlight the poor response of MM to conventional therapies and demonstrate that PLGA-DSF+Cu is a promising therapeutic approach. This discovery holds clinical significance as it suggests a viable, low-cost drug repurposing strategy that may improve survival outcomes and quality of life for patients with MM.

Citation

Lakshamanan, Y. (2025) In vitro and in vivo investigation of the anticancer activity and mechanism of disulfiram in malignant mesothelioma. University of Wolverhampton. https://wlv.openrepository.com/handle/2436/626194

Publisher

University of Wolverhampton

URI

https://wlv.openrepository.com/handle/2436/626194

Type

Thesis or dissertation

Language

en

Description

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.

Collections

Theses and Dissertations