Gliotoxin is an immunosuppressive agent which synthesized by Aspergillusfumigatus and other pathogenic fungi, inhibiting chymotrypsin-like activity of 20S proteasome.[1]
Gliotoxin shows an activity in inhibition of farnesyltransferase with IC50 value for 80 μM and geranyltransferaseI with IC50 value of 17 μM, which is stimulated interest in the potential antitumor activity of this epidithiodioxopiperazine. Also, with mean ± SD IC50 289 ± 328 μM, gliotoxin will inhibit proliferation of six breast cancer cell. And gliotoxinin ihibites intracellular farnesylation of LaminB and geranylgeranylation of Rap1 A following a dose-dependent manner. [2]
A randomized controlled study, which operated in the N-methyl-N-nitrosourea rat mammary carcinoma model, when 10 animals at 10 mg/kg were administered by subcutaneous injection weekly for 4 wk compared with 10 controls, supporting gliotoxin has antitumor activity apparently in vitro and little toxicity. The single doses can be well tolerated up to 25 mg/kg. [2].
The deficiency of the A. fumigatus mutant in gliotoxin-production resulted in less internalization of A. fumigatus conidia into the A549 cells compared with the wild type strain but an increase of phagocytosis by J774 macrophages., Gliotoxin showed to promote A. fumigatus internalization into A549 cells in a dose-dependent manner but inhibit the macrophage phagocytosis when at the concentrations of 10 to 50 ng/ml which are not cytotoxic to the A549 cells. In addition, gliotoxin is able to stimulate the PLD activity of A549 lung epithelial cells. It is efficient for promoting the internalization of A. fumigatus into the cells by this way. Gliotoxin also blocked the production of ROS in A549 epithelial cells significantly at a concentration range from 10 to 100 ng/ml [3].
References:
1.Pahl HL, Krauss B, Schulze-Osthoff K, et al. The immunosuppressive fungal metabolite gliotoxin specifically inhibits transcription factor NF-kappaB. The Journal of Experimental Medicine, 1996 , 183(4):1829-1840.
2.Vigushin DM, Mirsaidi N, Brooke G, et al. Gliotoxin is a dual inhibitor of farnesyltransferase and geranylgeranyltransferase I with antitumor activity against breast cancer in vivo. MEDICAL ONCOLOGY, 2004, 21(1):21-30.
3.Jia XD, Chen FY, Pan WH, et al. Gliotoxin promotes Aspergillus fumigatus internalization into type II human pneumocyte A549 cells by inducing host phospholipase D activation. Microbes and infection / Institut Pasteur, 2014, 16(6):491-501.