Biologic Functions of Hydroxychloroquine in Disease: From COVID-19 to Cancer

Chloroquine and Chemotherapeutic Compounds in Experimental Cancer Treatment

Chloroquine (CQ) and its derivate hydroxychloroquine (HCQ), the compounds with recognized ability to suppress autophagy, have been tested in experimental works and in clinical trials as adjuvant therapy for the treatment of tumors of different origin to increase the efficacy of cytotoxic agents. Such a strategy can be effective in overcoming the resistance of cancer cells to standard chemotherapy or anti-angiogenic therapy. This review presents the results of the combined application of CQ/HCQ with conventional chemotherapy drugs (doxorubicin, paclitaxel, platinum-based compounds, gemcitabine, tyrosine kinases and PI3K/Akt/mTOR inhibitors, and other agents) for the treatment of different malignancies obtained in experiments on cultured cancer cells, animal xenografts models, and in a few clinical trials. The effects of such an approach on the viability of cancer cells or tumor growth, as well as autophagy-dependent and -independent molecular mechanisms underlying cellular responses of cancer cells to CQ/HCQ, are summarized. Although the majority of experimental in vitro and in vivo studies have shown that CQ/HCQ can effectively sensitize cancer cells to cytotoxic agents and increase the potential of chemotherapy, the results of clinical trials are often inconsistent. Nevertheless, the pharmacological suppression of autophagy remains a promising tool for increasing the efficacy of standard chemotherapy, and the development of more specific inhibitors is required.

The OSR9 Regimen: A New Augmentation Strategy for Osteosarcoma Treatment Using Nine Older Drugs from General Medicine to Inhibit Growth Drive

As things stand in 2023, metastatic osteosarcoma commonly results in death. There has been little treatment progress in recent decades. To redress the poor prognosis of metastatic osteosarcoma, the present regimen, OSR9, uses nine already marketed drugs as adjuncts to current treatments. The nine drugs in OSR9 are: (1) the antinausea drug aprepitant, (2) the analgesic drug celecoxib, (3) the anti-malaria drug chloroquine, (4) the antibiotic dapsone, (5) the alcoholism treatment drug disulfiram, (6) the antifungal drug itraconazole, (7) the diabetes treatment drug linagliptin, (8) the hypertension drug propranolol, and (9) the psychiatric drug quetiapine. Although none are traditionally used to treat cancer, all nine have attributes that have been shown to inhibit growth-promoting physiological systems active in osteosarcoma. In their general medicinal uses, all nine drugs in OSR9 have low side-effect risks. The current paper reviews the collected data supporting the role of OSR9.