In vitro investigation of the anticancer activity and molecular mechanisms of action of albumin nano-encapsulated copper/zinc diethyldithiocarbamate in human pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest cancers, with a 5-year survival rate of 12%, and is projected to become the second leading cause of cancer-related mortality by 2030. Chemotherapy remains the main treatment option but offers limited benefits due to toxicity and chemoresistance, underscoring the need for novel, effective therapies. Disulfiram (DSF), an FDA-approved anti-alcoholism drug, has demonstrated potent anticancer activity when chelated with Cu²⁺ or Zn²⁺ ions to form copper diethyldithiocarbamate (Cu(DDC)₂) or zinc diethyldithiocarbamate (Zn(DDC)₂). However, the clinical anticancer application of DSF is hindered by a short plasma half-life (<4 minutes) and bioavailability challenges from separate Cu/Zn supplementation. To address these limitations, we developed albumin-based nanoparticles (Alb-CuDDC and Alb-ZnDDC) that encapsulate Cu(DDC)₂ or Zn(DDC)₂ to achieve stable, soluble, and long-circulating formulations. Alb-CuDDC and Alb-ZnDDC nanoparticles exhibited potent anticancer efficacy in PDAC patient-derived cultures from primary, circulating and metastatic sites, under normoxic, hypoxic and spheroid conditions. The albumin formulations showed effective cytotoxicity across a panel of PDAC cells and had similar IC₅₀ values to free drug (Alb-CuDDC: 193 ± 11 nM vs Free Cu(DDC)2: 210 ± 76 nM and Alb- ZnDDC: 7076 ± 612 vs Free Zn(DDC)2: 7122 ± 487 nM). Furthermore, Alb-CuDDC and Alb-ZnDDC synergistically enhanced the activity of gemcitabine and paclitaxel. To evaluate the potential for acquired resistance, long-term exposure studies were conducted in PANC1 and MDA-MB231 cells. Resistance emerged to Alb-ZnDDC but not to Alb-CuDDC or free DSF + Cu. The resistant cell lines (PANC1ZR6 and MDAMB231ZR7) represent a significant finding, being the first report of such resistance in the context of dithiocarbamate-based agents. Transcriptomic analysis led to the identification of a putative resistance mechanism which implicated cysteine protease inhibitor, CST1, as a mediator of Alb-ZnDDC resistance. This study highlights Alb-CuDDC and Alb-ZnDDC as promising nanotherapeutics for PDAC. However, the resistance profile of Alb-ZnDDC underscores the superior therapeutic potential of Alb-CuDDC. Moreover, the identification of CST1 provides insight into resistance mechanisms and highlights potential targets for overcoming similar resistance pathways.

Citation

Small, B. (2025) In vitro investigation of the anticancer activity and molecular mechanisms of action of albumin nano-encapsulated copper/zinc diethyldithiocarbamate in human pancreatic cancer cells. University of Wolverhampton. https://wlv.openrepository.com/handle/2436/626016

Publisher

University of Wolverhampton

URI

https://wlv.openrepository.com/handle/2436/626016

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