Mitochondrial electron-transport chain and other oxidizing agents are the prime pathways that generate excess ROS in vivo
Permanent modification of genetic material resulting from the oxidative damage is one of the vital steps involved in mutagenesis that leads to carcinogenesi
The most frequent DNA mutations caused during oxidative stress, initiated by ionizing radiation and other environmental carcinogens are 7,8-dihydro-8-oxoguanine (8-Oxo-G) and Thymine Glycol (TG)
daily doses up to 400 mg of HCQ or 250 mg CQ for several years are considered to carry an acceptable risk for CQ-induced retinopathies, with the exception of individuals of short stature
chronic CQ or HCQ therapy be monitored through regular ophthalmic examinations (3–6 month intervals), full blood counts and blood glucose level checks
long-term HCQ exposure, skeletal muscle function and tendon reflexes should be monitored for weakness
both CQ and HCQ, specific caution is advised in patients suffering from impaired hepatic function (especially when associated with cirrhosis), porphyria, renal disease, epilepsy, psoriasis, glucose-6-phosphate dehydrogenase deficiency and known hypersensitivity to 4-aminoquinoline compounds
CQ and HCQ can effectively increase the efficacy of various anti-cancer drugs
CQ can prevent the entrapment of protonated chemotherapeutic drugs by buffering the extracellular tumour environment and intracellular acidic spaces
This study recommends an adjuvant HCQ dose of 600 mg, twice daily.
HCQ addition was shown to produce metabolic stress in the tumours
HCQ (400 mg/day)
important effects of CQ and HCQ on the tumour microenvironment
The main and most studied anti-cancer effect of CQ and HCQ is the inhibition of autophagy
the expression levels of TLR9 are higher in hepatocellular carcinoma, oesophageal, lung, breast, gastric and prostate cancer cells as compared with adjacent noncancerous cells, and high expression is often linked with poor prognosis
TLR9-mediated activation of the NF-κB signalling pathway and the associated enhanced expression of matrix metalloproteinase-2 (MMP-2), MMP-7 and cyclo-oxygenase 2 mRNA
HCQ can activate caspase-3 and modulate the Bcl-2/Bax ratio inducing apoptosis in CLL, B-cell CLL and glioblastoma cells
In triple-negative breast cancer, CQ was shown to eliminate cancer stem cells through reduction of the expression of Janus-activated kinase 2 and DNA methyl transferase 1 [106] or through induction of mitochondrial dysfunction, subsequently causing oxidative DNA damage and impaired repair of double-stranded DNA breaks
CQ or HCQ would be considered for use in combination with immunomodulation anti-cancer therapies
Therapies used in combination with CQ or HCQ include chemotherapeutic drugs, tyrosine kinase inhibitors, various monoclonal antibodies, hormone therapies and radiotherapy
Most studies hypothesise that CQ and HCQ could increase the efficacy of other anti-cancer drugs by blocking pro-survival autophagy.
daily doses between 400 and 1200 mg for HCQ are safe and well tolerated, but two studies identified 600-mg HCQ daily as the MTD
HCQ is often administered twice daily to limit plasma fluctuations and toxicity