Temozolomide and AZD7762 Induce Synergistic Cytotoxicity Effects on Human Glioma Cells.

BACKGROUND/AIM: This study investigated the effects of temozolomide (TMZ) and/or checkpoint kinase inhibitor AZD7762 in human glioma cells. MATERIALS AND METHODS: Glioma cells were treated with TMZ and/or AZD7762 for 24 or 48 h, then the cellular survival was studied and the expression of various proteins was investigated. RESULTS: Both TMZ and AZD7762 induced concentration- and time-dependent cytotoxic effects, and combined TMZ and AZD7762 (TMZ+AZD) caused synergistic cytotoxic effects in glioma cells (p<0.05). AZD7762 suppressed the O6-methylguanine-DNA-methyltransferase (MGMT) expression. TMZ+AZD increased the expression of phospho-p53 (p-p53), p-p38 mitogen-activated protein kinase, and phosphatase and tensin homolog; and decreased the expression of p-extracellular signal-regulated kinase 1/2 and p-signal transducer and activator of transcription 3 in glioma cells. CONCLUSION: TMZ and AZD7762 combined induced synergistic cytotoxic effects on human glioma cells and such effects may be related to the AZD7762-induced suppression of MGMT expression and the modulation of multiple signaling pathways.

Influence of Growth Hormone and Glutamine on Intestinal Stem Cells: A Narrative Review.

Growth hormone (GH) and glutamine (Gln) stimulate the growth of the intestinal mucosa. GH activates the proliferation of intestinal stem cells (ISCs), enhances the formation of crypt organoids, increases ISC stemness markers in the intestinal organoids, and drives the differentiation of ISCs into Paneth cells and enterocytes. Gln enhances the proliferation of ISCs and increases crypt organoid formation; however, it mainly acts on the post-proliferation activity of ISCs to maintain the stability of crypt organoids and the intestinal mucosa, as well as to stimulate the differentiation of ISCs into goblet cells and possibly Paneth cells and enteroendocrine cells. Since GH and Gln have differential effects on ISCs. Their use in combination may have synergistic effects on ISCs. In this review, we summarize the evidence of the actions of GH and/or Gln on crypt cells and ISCs in the literature. Overall, most studies demonstrated that GH and Gln in combination exerted synergistic effects to activate the proliferation of crypt cells and ISCs and enhance crypt organoid formation and mucosal growth. This treatment influenced the proliferation of ISCs to a similar degree as GH treatment alone and the differentiation of ISCs to a similar degree as Gln treatment alone.

Suppression of miR-19b enhanced the cytotoxic effects of mTOR inhibitors in human neuroblastoma cells.

BACKGROUND: Mammalian target of rapamycin (mTOR) inhibitors exert significant antitumor effects on several cancer cell types. In this study, we investigated the effects of mTOR inhibitors, in particular the regulation of the microRNA, in neuroblastoma cells. METHODS: AZD8055 (a new mTOR inhibitor)- or rapamycin-induced cytotoxic effects on neuroblastoma cells were studied. Western blotting was used to investigate the expression of various proteins in the mTOR pathway. MicroRNA precursors and antagomirs were transfected into cells to manipulate the expression of target microRNA. RESULTS: AZD8055 exerted stronger cytotoxic effects than rapamycin in neuroblastoma cells (p<0.03). In addition, AZD8055 suppressed the mTOR pathway and increased the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in the neuroblastoma cells. AZD8055 significantly decreased miR-19b expression (p<0.005); in contrast, rapamycin increased miR-19b expression (p<0.05). Transfection of miR-19b antagomir into the neuroblastoma cells mimicked the effects of AZD8055 treatment, whereas miR-19b overexpression reversed the effects of AZD8055. Combination of miR-19b knockdown and rapamycin treatment significantly improved the sensitivity of neuroblastoma cells to rapamycin (p<0.02). CONCLUSION: Suppression of miR-19b may enhance the cytotoxic effects of mTOR inhibitors in neuroblastoma cells.