Critical role of heme oxygenase-1 in chaetoglobosin A by triggering reactive oxygen species mediated mitochondrial apoptosis in colorectal cancer.

The incidence rate of colorectal cancer (CRC) has been increasing and poses severe threats to human health worldwide and developing effective treatment strategies remains an urgent task. In this study, Chaetoglobosin A (ChA), an endophytic fungal metabolite from the medicinal herb-derived fungus Chaetomium globosum Km1126, was identified as a potent and selective antitumor agent in human CRC. ChA induced growth inhibition of CRC cells in a concentration-dependent manner but did not impair the viability of normal colon cells. ChA triggered mitochondrial intrinsic and caspase-dependent apoptotic cell death. In addition, apoptosis antibody array analysis revealed that expression of Heme oxygenase-1 (HO-1) was significantly increased by ChA. Inhibition of HO-1 increased the sensitivity of CRC cells to ChA, suggesting HO-1 may play a protective role in ChA-mediated cell death. ChA induced cell apoptosis via the induction of reactive oxygen species (ROS) and ROS scavenger (NAC) prevented ChA-induced cell death, mitochondrial dysfunction, and HO-1 activation. ChA promoted the activation of c-Jun N-terminal kinase (JNK), and co-administration of JNK inhibitor or siRNA markedly reversed ChA-mediated apoptosis. ChA significantly decreased the tumor growth without eliciting any organ toxicity or affecting the body weight of the CRC xenograft mice. This is the first study to demonstrate that ChA exhibits promising anti-cancer properties against human CRC both in vitro and in vivo. ChA is a potential therapeutic agent worthy of further development in clinical trials for cancer treatment.

Identification and characterization of the major antifungal substance against Fusarium Sporotrichioides from Chaetomium globosum.

Fusarium sporotrichioides, is a common soil-borne plant pathogen causing dry rot of potato in Northeast China. The objective of this study was to identify the main antifungal substances from Chaetomium globosum W7 against F. sporotrichioides. Strain W7 can significantly inhibit F. sporotrichioides without direct contact, suggesting that its antifungal substance was extracellular, and the solubility of this antifungal substance in ethyl acetate was superior to that in water. Acetone was selected as the optimum solvent for the extraction of the metabolites of C. globosum. Metabolites were then separated with thin-layer chromatography. Following antifungal tests on bands, a dark brown band with Rf value of 0.20 was determined as the antifungal substance, and identified as chaetoglobosin A. The antifungal activity test showed that the minimum inhibitory concentration of chaetoglobosin A to F. sporotrichioides was 9.45-10.50 µg/mL, IC50 being 4.344 µg/mL. Chaetoglobosin A also proved to have an excellent preventive effect on potato dry rot caused by F. sporotrichioides. To summarize, chaetoglobosin A was identified as the main active substance of C. globosum to inhibit F. sporotrichioides for the first time, and demonstrated a potential application value in agriculture.