Investigating the use of chloroquine as antineoplastic therapy
Chloroquine (CQ) is an oral lysosomotropic agent routinely used as an anti-malarial drug (Espina & Liotta, 2013). In recent years, it has been discovered that CQ also possesses anticancer effects, potentially due to the drug’s inhibition of autophagy (Kimura, Takabatake, Takahashi, & Isaka, 2012). Autophagy is a normal cellular pathway that allows for the degradation of cytoplasmic contents. In cancer cells autophagy can also serve as a pro-survival pathway under stressful metabolic conditions, ultimately promoting the survival of malignant cells (Sui et al., 2013). Therefore, in recent years CQ has been speculated as a potential antineoplastic therapy. When administered in conjunction with typical chemotherapeutic agents, CQ also has the potential to decrease acquired drug resistance, enhance the efficacy of chemotherapeutic agents, and prevent pre-invasive cells from transitioning to invasive cells (Espina & Liotta, 2013). However, this potential antineoplastic effect has been observed to vary somewhat between cancer types and phases of tumorigenesis, and the precise antineoplastic mechanism of CQ is not clearly understood (Sui et al., 2013).
The purpose of this literature review was to evaluate the current evidence in order to compare the efficacy and safety of the use of CQ as an antineoplastic agent in various types of cancer. Additionally, the conjectured antineoplastic effects of CQ discussed in each reviewed study were compared in order to gain greater understanding of the probable mechanism of action of CQ in cancer cells.