Chloroquine (dihydrochloride)

Chloroquine dihydrochloride is an antimalarial and anti-inflammatory agent widely used to treat malaria and rheumatoid arthritis. Chloroquine dihydrochloride is an autophagy and toll-like receptors (TLRs) inhibitor. Chloroquine dihydrochloride is highly effective in the control of SARS-CoV-2 (COVID-19) infection in vitro (EC₅₀=1.13 μM)^[1][2][3][4]. In Vitro: Chloroquine dihydrochloride (20 μM) inhibits IL-12p70 release and reduces Th1-priming capacity of activated human monocyte-derived Langerhans-like cells (MoLC). Chloroquine dihydrochloride (20 μM) enhances IL-1-induced IL-23 secretion in MoLC and subsequently increases IL-17A release by primed CD4+ T cells[1]. Chloroquine dihydrochloride (25 μM) suppresses MMP-9 mRNA expression in normoxia and hypoxia in parental MDA-MB-231 cells. Chloroquine dihydrochloride has cell-, dose- and hypoxia-dependent effects on MMP-2, MMP-9 and MMP-13 mRNA expression^[2]. TLR7 and TLR9 inhibition using IRS-954 or Chloroquine dihydrochloride significantly reduces HuH7 cell proliferation in vitro^[3].
Chloroquine dihydrochloride (0.01-100 μM; 48?hours) potently blocked virus infection (vero E6 cells infected with SARS-CoV-2) at low-micromolar concentration (EC50=1.13?μM). Chloroquine dihydrochloride blocks virus infection by increasing endosomal pH required for virus/cell fusion, as well as interfering with the glycosylation of cellular receptors of SARS-CoV^[4]. In Vivo: Chloroquine dihydrochloride (80 mg/kg, i.p.) does not prevent the growth of the triple-negative MDA-MB-231 cells with high or low TLR9 expression levels in the orthotopic mouse model^[2].
TLR7 and TLR9 inhibition using IRS-954 or Chloroquine dihydrochloride significantly inhibits tumour growth in the mouse xenograft model. HCC development in the DEN/NMOR rat model is also significantly inhibited by Chloroquine^[3].