The utility of chloroquine in cancer therapy

The anti-malarial drug chloroquine has recently been discovered as a novel anti-tumor agent. This article is to review the recent development of chloroquine being used in cancer therapy.

PubMed, ScienceDirect and ClinicalKey served as the major databases. Key words included 'chloroquine', 'cancer', and 'autophagy'. The publication date was up to June 2015.

Chloroquine mainly executes its anti-tumor function through inhibition of autophagy. It can accumulate inside the lysosome resulting in lysosomal membrane permeabilization (LMP) which will eventually lead to apoptosis. Chloroquine has been shown to stabilize p53 and induce p53-dependent apoptosis or cell cycle arrest. It can also inhibit ABC (ATP-binding cassette) family protein. The anti-cancer effect of chloroquine has been observed both in vitro and in vivo. However, it is considered more as a potential chemotherapy and radiotherapy sensitizer rather than an antineoplastic.

Although the utility of chloroquine is promising in cancer therapy, some safety issues have been brought to attention, and further studies on safety profile and the signs of clinical activity of chloroquine including its derivatives should be conducted.