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Dihydroartemisinin (DHA) has been reported to possess anti-cancer activity against many cancers. However, the pharmacologic effect of DHA on HBV-positive hepatocellular carcinoma (HCC) remains unknown. Thus, the objective of the present study was to determine whether DHA could inhibit the proliferation of HepG2.2.15 cells and uncover the underlying mechanisms involved in the effect of DHA on HepG2.2.15 cells. We found that DHA effectively inhibited HepG2.2.15 HCC cell proliferation both in vivo and in vitro. DHA also reduced the migration and tumorigenicity capacity of HepG2.2.15 cells. Regarding the underlying mechanisms, results showed that DHA induced cellular senescence by up-regulating expression levels of proteins such as p-ATM, p-ATR, γ-H2AX, P53, and P21 involved in DNA damage response. DHA also induced autophagy (green LC3 puncta gathered together and LC3II/LC3I ratio increased through AKT-mTOR pathway suppression). Results also revealed that DHA-induced autophagy was not linked to senescence or cell death. TPP1 (telomere shelterin) overexpression could not rescue DHA-induced anticancer activity (cell proliferation). Moreover, DHA down-regulated TPP1 expression. Gene knockdown of TPP1 caused similar phenotypes and mechanisms as DHA induced phenotypes and mechanisms in HepG2.2.15 cells. These results demonstrate that DHA might inhibit HepG2.2.15 cells proliferation through inducing cellular senescence and autophagy. [BMB Reports 2019; 52(8): 520-524].

Self-assembled DNA nanostructures hold great potentials in biomedical applications. Nevertheless, the negatively charged DNA backbone and susceptivity to enzyme degradation pose challenges to this regard. Engineering the surface properties of DNA nanostructures by assembling DNA with guest molecules in magnesium-free system is promising to solve these issues. In this study, the polyamines-mediated DNA self-assembly with an emphasis on the valency of polyamines is investigated. Both spermine, spermidine, and putrescine can assemble DNA tetrahedron under appropriate concentrations. The cytotoxicity and cellular uptake efficiencies vary with the polyamine valency. Compared with magnesium-assembled DNA tetrahedron, polyamine-assembled DNA tetrahedron exhibits higher cellular uptake efficiency and serum stability. Circular dichroism spectrum results indicate that polyamines induce DNA conformation slightly shifting from B form to A form. The improved performances of polyamine-assembled DNA tetrahedrons under physiological settings are attributed to the surface properties that altered by guest molecules polyamine. The current study suggests that engineering the surface properties of DNA nanostructures by assembling them with guest cationic species is promising to further their biomedical applications.

Nearly half of human cancers harbor p53 mutations, and mutant p53 (mutp53) promotes carcinogenesis, metastasis, tumor recurrence and chemoresistance. mutp53 is observed in 30% of breast carcinomas, including triple‐negative breast cancer (TNBC), and thus mutp53 is a promising target for treatment of TNBC. In this study, we investigated the effect of a phosphatidylinositide 3 kinase/mammalian target of rapamycin dual inhibitor, NVP‐BEZ235 (BEZ235), on two TNBC cell lines with mutp53: MDA‐MB‐231 and MDA‐MB‐468. Cell growth, migration and colony‐formation abilities were detected by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide, scratch assay, transwell and soft agar assay, revealing that BEZ235 can inhibit the growth, migration and colony‐formation abilities of TNBC cells. In addition, BEZ235 caused degradation of mutp53 in these cells. We investigated the underlying mechanism by inhibiting proteasome function using MG132 and inhibiting autophagy using 3‐methyladenine and shRNAs. We observed that BEZ235 may induce autophagy through repression of the Akt/mammalian target of rapamycin signaling pathway. The observed interplay between mutp53 and autophagy in TNBC cells was examined further by knockdown of ATG5 and ATG7, revealing that degradation of mutp53 induced by BEZ235 may be independent of the ubiquitin–proteasome pathway and autophagy mediated by ATG5 and ATG7. Moreover, we found evidence of positive feedback between mutp53 and autophagy in TNBC cells. In conclusion, BEZ235 may exert antitumor effects against TNBC cells by targeting mutp53, and this may have implications for the development of future therapies., NVP‐BEZ235 is a phosphatidylinositide 3 kinase/mammalian target of rapamycin dual inhibitor, which exerts an antitumor effect against two triple‐negative breast cancer cell lines harboring mutant p53 protein: MDA‐MB‐231 and MDA‐MB‐468. BEZ235 induces autophagy in these cells, possibly through repression of the AKT/mammalian target of rapamycin pathway. Degradation of mutant p53 induced by BEZ235 is independent of the ubiquitin–proteasome pathway and autophagy. BEZ235 may be a potential therapeutic target for triple‐negative breast cancers with mutant p53.

Hepatocellular carcinoma (HCC) is a worldwide malignancy. To date, surgery is still the most effective treatment with curative potential, but only about 20% of patients with HCC are eligible for surgical intervention. Therefore exploring the pathogenesis of liver cancer, looking for molecules targeting therapy, is very important. Telomeres, the chromosome extremities, are protected by specific proteins, such as POT1, RAP1, TIN2, TRF1, TRF2,and TPP1. More and more findings have discovered that TPP1 plays an important role in the tumorigenesis. However, the mechanism of TPP1 in HCC remains unknown. The purpose of this study is to explore the role of TPP1 in HCC. Currently 42 cases of HCC patients were recruited in this study. First, the patients' tumor tissue, adjacent tissue and normal tissue were analyzed by Western blot. The results showed that TPP1 expression in patients' adjacent tissue and normal tissue was lower than that in tumor tissue, respectively (P Citation Format: Jiang Zou, Ru Sun, Jingruo Xia, Dan Xiao, Chang Liu, Hebin Liao, Lei Xu, Qiang Ma, Yan Cai, Jingdong Li, Xiaolan Guo. The role of telomere protective protein TPP1 in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 341.