# Effects of Disulfiram and Copper in Combination with Temozolomide on Survival, Tumor Size and Autophagy Markers in an F98 Rat Glioma Model

## TL;DR

This study shows that combining disulfiram and copper with temozolomide improves survival and activates autophagy in a rat model of glioblastoma.

## Contribution

The first demonstration of TMZ-DSF-Cu combination effects on survival and autophagy in an F98 rat glioma model.

## Key findings

- TMZ-DSF-Cu significantly increased mean survival in F98 glioma-bearing rats.
- The combination induced autophagy markers LC3 and p62.
- Copper was essential for the observed effects, as neither TMZ nor DSF alone achieved the same results.

## Abstract

Glioblastoma (GBM) is the most common and most aggressive malignant primary brain tumor in adults with a median survival of 15 months. One of the main factors responsible for the poor prognosis of GBM is resistance to treatment with temozolomide (TMZ), which has been attributed—among other factors—to autophagy. Preclinical studies have shown that the combination of disulfiram (DSF) with copper (Cu) possesses anti-GBM activity, through various mechanisms, including re-sensitization to TMZ. Herein, we tested for the first time the effects of DSF and Cu in combination with TMZ on the survival of Fischer rats bearing F98 glioma, a model characterized by inherent resistance to TMZ. Tumor size evaluation by Magnetic Resonance Imaging as well as immunofluorescence analysis of two autophagy markers, namely microtubule-associated protein 1 light chain 3 (LC3) and sequestosome-1 (SQSTM1)/p62 (p62), were also performed. According to our results, TMZ-DSF-Cu significantly increased mean survival and induced both LC3 and p62 autophagy markers. Interestingly, these results could not be achieved in the absence of Cu, neither in the presence of TMZ alone, suggesting the importance of combining DSF with Cu in order to sensitize glioma to TMZ, presumably via implication of autophagy modulation.