Cyclosporin A

Cyclosporin A is a selective cyclophilin inhibitor with IC50 value of 7 nM [1].

Cyclophilins are isomerase enzymes and involve in a variety of functions related to cell metabolism and energy homeostasis. It has been reported that the over expression of cyclophilins were observed in inflammation or malignancy.

Cyclosporin A is a potent cyclophilin inhibitor which is responsible for the opening of the MPTP (mitochondrial permeability transition pore). When tested with retinal ganglion cells, Cyclosporin A showed a high selectivity for the expression of cyclophilin D and prolonged the cells survival [2]. In human First-Trimester Trophoblast Cells, Cyclosporin A treatment promoted cells growth and invasiveness by inhibiting Ca2+/Calcineurin/NFAT signal [3]. Cyclosporin A treatment promoted the apoptosis of T-cell by upregulating Fas/FasL and caspase activities [4]. Treated human T cells with Cyclosporin A suppressed T cell activation by inhibiting calcineurin and NFATc which are responsible for T cell function [1].

In retinal ischemia C57BL/6 mouse model, Cyclosporin A treatment significantly prevented the up regulation of cyclophilin D and ameliorated the death of neuronal cells in vivo [2].

Cyclosporin A has also been reported to inhibit the entry of hepatitis B and C virus through interfering NTCP reportor [5]. In CRC cell lines (CACO-2, HT-29, HCT-116 and LOVO), Cyclosporin A treatment also could impair cell growth via without calcineurin pathway while the mechanism was still undermined [6].

References:
[1].  Minguillon, J., et al., Concentrations of cyclosporin A and FK506 that inhibit IL-2 induction in human T cells do not affect TGF-beta1 biosynthesis, whereas higher doses of cyclosporin A trigger apoptosis and release of preformed TGF-beta1. J Leukoc Biol, 2005. 77(5): p. 748-58.
[2].  Kim, S.Y., et al., Inhibition of cyclophilin D by cyclosporin A promotes retinal ganglion cell survival by preventing mitochondrial alteration in ischemic injury. Cell Death Dis, 2014. 5: p. e1105.
[3].  Du, M.R., et al., Cyclosporin A promotes growth and invasiveness in vitro of human first-trimester trophoblast cells via MAPK3/MAPK1-mediated AP1 and Ca2+/calcineurin/NFAT signaling pathways. Biol Reprod, 2008. 78(6): p. 1102-10.
[4].  Gao, J., et al., Mitochondrial permeability transition pore in inflammatory apoptosis of human conjunctival epithelial cells and T cells: effect of cyclosporin A. Invest Ophthalmol Vis Sci, 2013. 54(7): p. 4717-33.
[5].  Nkongolo, S., et al., Cyclosporin A inhibits hepatitis B and hepatitis D virus entry by cyclophilin-independent interference with the NTCP receptor. J Hepatol, 2014. 60(4): p. 723-31.
[6].  Werneck, M.B., et al., Cyclosporin A inhibits colon cancer cell growth independently of the calcineurin pathway. Cell Cycle, 2012. 11(21): p. 3997-4008.