Glioma is a common primary malignant tumor that has a poor prognosis and often develops drug resistance. The coumarin derivative osthole has previously been reported to induce cancer cell apoptosis. Recently, we found that it could also trigger glioma cell necroptosis, a type of cell death that is usually accompanied with reactive oxygen species (ROS) production. However, the relationship between ROS production and necroptosis induced by osthole has not been fully elucidated. In this study, we found that osthole could induce necroptosis of glioma cell lines U87 and C6; such cell death was distinct from apoptosis induced by MG-132. Expression of necroptosis inhibitor caspase-8 was decreased, and levels of necroptosis proteins receptor-interacting protein 1 (RIP1), RIP3 and mixed lineage kinase domain-like protein were increased in U87 and C6 cells after treatment with osthole, whereas levels of apoptosis-related proteins caspase-3, caspase-7, and caspase-9 were not increased. Lactate dehydrogenase release and flow cytometry assays confirmed that cell death induced by osthole was primarily necrosis. In addition, necroptosis induced by osthole was accompanied by excessive production of ROS, as observed for other necroptosis-inducing reagents. Pretreatment with the RIP1 inhibitor necrostatin-1 attenuated both osthole-induced necroptosis and the production of ROS in U87 cells. Furthermore, the ROS inhibitor N-acetylcysteine decreased osthole-induced necroptosis and growth inhibition. Overall, these findings suggest that osthole induces necroptosis of glioma cells via ROS production and thus may have potential for development into a therapeutic drug for glioma therapy. Glioma is the most common central nervous system tumor in adults and children [1,2], and glioblastoma is the most malignant glioma ranked grade Ⅳ [3]. The average incidence of glioblastoma is 3.2/100 000 population, and the 5-year survival rate is about 6.8% [4]. Although the occurrence of glioblastoma is relatively Abbreviations DCFH-DA, 2 0 , 7 0-dichloro-hydrofluorescein diacetate;

Epigallocatechin-3-gallate (EGCG), a polyphenol present in green tea, exhibits anticancer effects in various types of cancer. A number of studies have focused on the effects of EGCG on lung cancer, but not ovarian cancer. Previous reports have implicated that EGCG suppressed ovarian cancer cell proliferation and induced apoptosis, but its potential anticancer mechanisms and signaling pathways remain unclear. Thus, it is necessary to determine the anti-ovarian cancer effects of EGCG and explore the underlying mechanisms. In the present study, EGCG exerted stronger proliferation inhibition on SKOV3 cells compared with A549 cells and induced apoptosis in SKOV3 cells, as well as upregulated PTEN expression and downregulated the expression of phosphoinositide-dependent kinase-1 (PDK1), phosphor (p)-AKT and p-mTOR. These effects were reversed by the PTEN inhibitor VO-Ohpic trihydrate. The results of the mouse xenograft experiment demonstrated that 50 mg/kg EGCG exhibited increased tumor growth inhibition compared with 5 mg/kg paclitaxel. In addition, PTEN expression was upregulated, whereas the expression levels of PDK1, p-AKT and p-mTOR were downregulated in the EGCG treatment group compared with those in untreated mice in vivo. In conclusion, the results of the present study provided a new underlying mechanism of the effect of EGCG on ovarian cancer and may lead to the development of EGCG as a candidate drug for ovarian cancer therapy.

MicroRNA-30a-5p (miR-30a-5p), which functions as a tumor suppressor, has been reported to be downregulated in colorectal cancer (CRC) tissues and to be associated with cancer invasion. However, the detailed regulatory mechanism of curcumol in the malignant progression of CRC remains unknown. MTT, Transwell, scratch, western blotting and reverse transcription-quantitative PCR assays were performed to examine how curcumol inhibited CRC cell viability, invasion and migration, and to detect the role of miR-30a-5p and curcumol in the invasion and Hippo signaling pathways of CRC cells. The present study revealed that miR-30a-5p expression was downregulated in human CRC tissues and cells. The results demonstrated that miR-30a-5p downregulation was accompanied by the inactivation of the Hippo signaling pathway, which was demonstrated to promote CRC cell viability, invasion and migration. Curcumol treatment was identified to increase miR-30a-5p expression and to activate the Hippo signaling pathway, which in turn inhibited the invasion and migration of CRC cells. Overexpression of miR-30a-5p enhanced the effects of curcumol on cell invasion and migration, and the Hippo signaling pathway in CRC cells. Furthermore, downregulation of miR-30a-5p reversed the effects of curcumol on cell invasion and migration, and the Hippo signaling pathway in CRC cells. These findings identified novel signaling pathways associated with miR-30a-5p and revealed the effects of curcumol on miR-30a-5p expression. Therefore, curcumol may serve as a potential therapeutic strategy to delay CRC progression.

Background: Osthole is a natural coumarin which has been proved to inhibit growth of cancer cells by inducing cancer cells death, while its mechanism of anticancer remains unclearly. In our study, we found that osthole activated multiple forms of cell death including apoptosis, secondary necrosis and mitophagy in receptor interacting protein kinase (RIP) 3-deficient cervical cancer HeLa cells. Methods: Cell viability was detected by MTT assay. Cell membrane integrity was detected by LDH release assay and PI staining. Cell apoptosis and necrosis were detected by flow cytometry assay. Reactive oxygen species (ROS) was detected by DCFH-DA staining and mitochondrial membrane potential (MMP) was detected by JC-1 staining using flow cytometry. The expression of proteins was detected by western blotting assay and proteomics. Xenograft tumor model was used to evaluate the effect of osthole in vivo.Results: Our study showed osthole caused HeLa cells apoptosis and secondary necrosis, which is a phenomenon of the apoptotic cells’ plasma membrane breakdown. And when Hela cells pretreatment with Z-DEVD-FMK, an irreversible caspase-3 inhibitor, not only inhibited osthole-induced apoptosis but also necrosis. Moreover, we found that Z-DEVD-FMK reversed the effect of osthole on the induction of cleaved the N-terminal fragment of GSDME in Hela cells. Furthermore, inhibition of NAD (P) H: quinone oxidoreductase 1 (NQO1) by osthole induced the overproduction of reactive oxygen species (ROS). ROS inhibitor N-Acetyl-L-cysteine (NAC) not only reduced osthole-induced apoptosis, but also reversed its effect on the necrotic induction and the GSDME N-terminal generation. It was shown that osthole decreased mitochondrial membrane potential (MMP) and increased the expression of PTEN-induced putative kinase 1 (PINK1) and Parkin, which indicated that the activation of mitophagy induced by osthole. Meanwhile, as well as apoptosis and secondary necrosis, mitophagy was also restrained by NAC. Conclusions: In conclusion, all these data suggested that osthole induced apoptosis, secondary necrosis and mitophagy via NQO1-mediated ROS overproduction.