Effects and mechanism of siomycin A on the growth and apoptosis of MiaPaCa-2 cancer cells.

Siomycin A is a type of thiopeptide antibiotic that is isolated from the fermentation products of an endophytic actinomycin, which is derived from the medicinal plant Acanthopanax senticosus. The present study investigated whether siomycin A has antitumor effects in vitro on a variety of cell lines. A Cell Counting Kit-8 assay was performed to detect the effects of siomycin A on cell viability; morphological changes in the MiaPaCa-2 cell line were analyzed using an inverted phase contrast microscope. A Transwell migration assay was applied to detect cell migration ability. The cytoskeleton was observed by laser confocal microscopy, and apoptosis was detected using flow cytometry. A western blot assay was used to detect the expression of matrix metalloproteinase (MMP)-2, MMP-9 and α-tubulin. The results revealed that siomycin A inhibited the proliferation of human tumor cell lines of different origins. As the concentration of siomycin A increased, the cell density decreased gradually and cells exhibited a morphological change from spindle to spherical shape. Furthermore, 24 h after administration, the cell migration ability was inhibited. The cytoskeleton complexity and morphological changes were increased after administration of siomycin A. The percentage of apoptotic cells was significantly increased and the expression levels of MMP-2, MMP-9 and α-tubulin were downregulated by siomycin A. Therefore, siomycin A was determined to effectively inhibit the proliferative ability of a variety of human tumor cell lines. Siomycin A was also determined to affect the cytoskeleton of tumor cells by downregulating the expression of α-tubulin protein.

LncRNA ANRIL affects the sensitivity of ovarian cancer to cisplatin via regulation of let-7a/HMGA2 axis.

This paper tried to explore ANRIL expression in ovarian cancer and how it affects cisplatin-sensitivity of ovarian cancer cells via regulation of let-7a/high-mobility group protein A2 (HMGA2) axis. qRT-PCR was used to detect ANRIL and let-7a levels in ovarian cancer tissues and cell lines (SKOV3 and SKOV3/DDP). Then cells were randomly assigned into Blank, negative control siRNA, ANRIL siRNA, let-7a inhibitor, and ANRIL siRNA+let-7a-inhibitor groups. CCK-8 assay was applied for assessing cell viability of cells treated with different concentrations of cisplatin. Flow cytometry was employed to test cell apoptosis rate. qRT-PCR and Western blot were performed for related molecules detection. Nude mice transplanted with SKOV3/DDP cells were used to confirm the effects of ANRIL siRNA on the cisplatin-sensitivity. Ovarian cancer tissues and cisplatin-resistant cells had increased ANRIL expression and decreased let-7a expression, and those patients with higher clinical stage and pathological grade showed higher ANRIL and lower let-7a. Dual-luciferase reporter-gene assay confirmed the targeting relationship between ANRIL and let-7a, and between let-7a and HMGA2. The cell viability and cisplatin IC50 were decreased in ANRIL siRNA group exposed to different concentrations of cisplatin, with enhanced apoptosis, as well as elevated let-7a and declined HMGA2, which would be reversed by let-7a inhibitor. Meanwhile, ANRIL down-regulation enhanced the inhibitory effect of cisplatin on tumor growth of nude mice and reduced tumor weight. Silencing ANRIL expression reduced HMGA2 expression to promote the apoptosis and improve cisplatin-sensitivity of ovarian cancer cells via up-regulating let-7a expression.

[Advances in the research of inhibitors of enzymes of bacterial peptidoglycan biosynthesis].

In recent years, owing to the abuse of antibiotics, the widespread of resistant bacterial strains became a serious threat to public health. This status demands development of new antibacterial agents with novel mechanisms of action. The reason for the limited new antibacterials is the small number of effective therapeutic targets, which cannot meet the current needs for the multiple drug-resistant treatment. Screening for new targets is the key step in the development of novel antibacterial agents. Peptidoglycan is the main component of the cell wall of bacteria, which is essential for survival of pathogenic bacteria. Within the biochemical pathway for peptidoglycan biosynthes is the Murligases, described in this review as highly potential targets for the development of new classes of antibacterial agents. This review provides an in-depth insight into the recent developments in the field of inhibitors of the Mur enzymes (MurA-F). Moreover, the reasons for the lack of candidate inhibitors and the challenges to overcome the hurdles are also discussed.