# Disulfiram activates autophagy via proteasome inhibition and c-Fos/beclin-1 upregulation, synergizing with chloroquine

## TL;DR

Disulfiram activates autophagy in colorectal cancer cells and works better with chloroquine, offering a new combination therapy approach.

## Contribution

The study reveals dual mechanisms of disulfiram-induced autophagy and validates its synergistic effect with chloroquine in colorectal cancer.

## Key findings

- Disulfiram activates autophagy via proteasome inhibition and upregulation of c-Fos/beclin-1.
- Combining disulfiram with chloroquine synergistically enhances anti-tumor efficacy in colorectal cancer.
- Transcriptomic analysis shows disulfiram promotes c-Fos/AP-1 binding to the BECN1 promoter.

## Abstract

Disulfiram (DSF), a clinically approved anti-alcoholism drug, exerts anti-tumor activity through its copper metabolite CuET by inhibiting the ubiquitin-proteasome system (UPS). However, its regulatory mechanisms on autophagy and potential for combination therapy remain to be clarified. Here, we revealed that DSF activates autophagy in colorectal cancer (CRC) cells via dual mechanisms: compensatory autophagy induction through proteasome inhibition by targeting the p97-NPL4 axis, and transcriptional upregulation of the autophagy-related gene BECN1 via FOS gene activation. Transcriptomic analysis identified that DSF enhances c-Fos expression, promoting c-Fos/AP-1 complex binding to the BECN1 promoter to drive beclin-1 expression. Furthermore, combining DSF with the autophagy inhibitor chloroquine (CQ) synergistically enhanced anti-tumor efficacy both in vitro and in vivo. DSF-induced autophagy may mitigate its pro-apoptotic effects, while autophagy inhibition fully blocks protein degradation pathways, leading to lethal protein accumulation. This study elucidates DSF’s dual regulation of autophagy through UPS suppression and the c-Fos/beclin-1 axis, and validates the synergistic efficacy of DSF combination with CQ in CRC, providing a theoretical foundation and translational potential for DSF-based combination therapies.