Effects of griseofulvin on apoptosis through caspase-3- and caspase-9-dependent pathways in K562 leukemia cells: An in vitro study

OSMAC Strategy Integrated with Molecular Networking for Accessing Griseofulvin Derivatives from Endophytic Fungi of Moquiniastrum polymorphum (Asteraceae)

Three endophytic fungi isolated from Moquiniastrum polymorphum (Less.) G. Sancho (Asteraceae) were cultivated using the one strain many compounds (OSMAC) strategy to evaluate the production of griseofulvin derivatives. Extracts obtained were analyzed by HPLC-MS/MS and the chromatographic and spectrometric data used to elaborate a feature-based molecular network (FBMN) through the GNPS platform. This approach allowed the observation of differences such as medium-specific and strain-specific production of griseofulvin derivatives and variations of cytotoxic activity in most extracts. To evaluate the efficiency of the OSMAC approach allied with FBMN analysis in the prospection of compounds of biotechnological interest, griseofulvin and 7-dechlorogriseofulvin were isolated, and the relative concentrations were estimated in all culture media using HPLC-UV, allowing for the inference of the best strain-medium combinations to maximize its production. Malt extract-peptone broth and Wickerham broth media produced the highest concentrations of both secondary metabolites.

Downregulation of microRNA-873 attenuates insulin resistance and myocardial injury in rats with gestational diabetes mellitus by upregulating IGFBP2

Gestational diabetes mellitus (GDM) is a metabolic disorder characterized by insulin resistance, and patients with GDM have a higher risk of cardiovascular disease. Multiple microRNAs (miRNAs) are reported to be involved in the regulation of myocardial injury. Moreover, miR-873 was predicted to target insulin-like growth factor binding protein 2 (IGFBP2) through bioinformatic analysis, which was further confirmed using a luciferase assay. Thus, our objective was to assess whether microRNA-873 (miR-873) affects insulin resistance and myocardial injury in an established GDM rat model. The GDM rats were treated with miR-875 mimic or inhibitor or IGFBP2 siRNA. The effects of miR-875 and IGFBP2 on the cardiac function, insulin resistance, and myocardial injury were evaluated by hemodynamic measurements, determination of biochemical indices of myocardium and serum, and insulin homeostatic model assessment. The results indicated that downregulation of miR-873 upregulated the expression of IGFBP2 and promoted the activation of phosphatidylinositol-3 kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) axis. With downregulation of miR-873 in GDM rats, the cardiac function was improved and the myocardial apoptosis was inhibited, coupled with elevated activity of superoxide dismutase, carbon monoxide synthase, and the nitric oxide content. In addition, the inhibition of miR-873 in GDM rats modulated the insulin resistance and reduced myocardial apoptosis. Overall, the data showed that inhibition of miR-873 by targeting IGFBP2 may regulate the insulin resistance and curtail myocardial injury in GDM rats through activating the PI3K/AKT/mTOR axis, thus providing a potential means of impeding the progression of GDM.

Effects of small nucleolar RNA SNORD44 on the proliferation, apoptosis and invasion of glioma cells

To master the effect of small nucleolar RNA, SNORD44, on the proliferation, apoptosis and invasion of glioma cells and its relevant mechanism. SNORD44 and GAS5 expression in glioma tissues and cells was detected through qRT-PCR. Then, the glioma cell lines (U87 and U251) were divided into different groups with different treatments. Cell proliferation was determined by MTT assay, while the abilities of the cell migration and invasion were measured by wound-healing test and Transwell assay, respectively. Cell apoptosis were detected by flow cytometry and TUNEL assay. The expression of apoptosis proteins was quantified through Western blotting. Finally, the xenograft models were established on nude mice to investigate the effects of SNORD44 on the growth of glioma and the expressions of Ki67, MMP2 and MMP9 in vivo. SNORD44 and GAS5 were down-regulated in glioma tissues and cells in a positive correlation. Either SNORD44 or GAS5 overexpression decreased the proliferation, invasion and migration of U87 and U251 cells with the up-regulation of apoptosis rates, as well as the expressions of cleaved PARP, caspase 3, caspase 8 and caspase 9. Moreover, the in vivo experiment showed that overexpression of SNORD44 blocked the growth of glioma xenograft in nude mice accompanying with the inhibition of Ki67, MMP2 and MMP9 expressions. The combination overexpression of SNORD44 and GAS5 gained better inhibitory effects on glioma cells. Overexpression of SNORD44 and GAS5 activate the caspase-dependent apoptosis pathway to facilitate the apoptosis with the inhibited proliferation, invasion and migration of glioma cells.

Cytotoxicity of three South African medicinal plants using the Chang liver cell line

BACKGROUND

Arctotis arctotoides, Gasteria bicolor and Pittosporum viridiflorum are commonly used in the Eastern Cape, South Africa by traditional healers for the treatment of opportunistic fungal infections in HIV/AIDS patients. Unfortunately, there is a dearth of published data regarding the toxicity of the selected plants, despite the fact that experimental screening of toxicity is crucial to guarantee the safety of the users.

MATERIALS AND METHODS

Therefore, it was decided to evaluate the cytotoxicity of the hexane and acetone extracts of the medicinal plants against the Chang Liver cell line using the in vitro MTT assay. Different concentrations of the extracts were added into 24-hour cultured cells and incubated for 72 hours under specific condition (37 °C, 5% CO2). Cell survival was evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

Depending on the dosage and duration of treatment, the cytotoxic effects of Gasteria bicolor and Pittosporum viridiflorum were considered relatively weak (but not entirely absent) and less of a toxicity risk. Arctotis arctotoides extracts were the most toxic both in terms of IC50 values as well as the steeper slope of the dose response curve. The IC50 values for the acetone and hexane extracts of this plant were 17.4 and 12.4 µg/ml respectively.

CONCLUSION

These relatively low values raise concern for potential hepatotoxic effects and deserve further investigation or at least a warning to potential users.