Response to letter to the Editor: The therapeutic strategy of drug re-positioning to induce autophagic cell death in brain malignancy

Abstract

We thank Dr Yoshida for his valuable comments and interest in our study which describes the anti-cancer activity of DS00329, a novel derivative of the anti-psychotic drug phenothiazine, in glioblastoma multiforme (GBM) [1]. We appreciate the information provided by Dr Yoshida that illustrates that the activation of autophagy is an important mechanism by which neurochemical compounds and dopamine receptor D4 antagonists inhibit GBM proliferation [2]. Furthermore, we agree with him that levels of p62/SQSTM1 is an important indicator of the autophagic state of cells and that, in addition to our results showing an increase in LC3-11, it would be important to determine the impact of DS00329 on p62/SQSTM1 levels in glioblastoma cells. Indeed, increased LC3‐II levels can be associated with either enhanced autophagosome synthesis or reduced autophagosome turnover.