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MicroRNA-191 (miR-191), a small non-coding RNA, is involved in disease development and cancer diagnosis and prognosis. However, how miR-191 functions in colorectal cancer remains largely unclear. In this study, we show that miR-191 is highly expressed in colon tumor tissues, and that inhibition of miR-191 leads to decreased cell growth, proliferation and tumorigenicity in a xenograft model. Overexpression of miR-191 in colorectal cancer cell lines alters cell cycle progression and cell resistance to 5-Fu induced cell apoptosis. Mechanistic studies demonstrated that miR-191 directly binds to the 3′UTR of the C/EBPβ mRNA and mediates a decrease in the mRNA and protein expression of C/EBPβ. We further showed that C/EBPβ induces growth arrest in a colorectal cancer cell line and that its expression is negatively correlated with the miR-191 level in patient samples. Our findings suggest that miR-191 may be a potential gene therapy target for the treatment of colorectal cancer.

Over the last seven years, expanding research efforts focused on sesterterpenoids has led to the isolation, identification, and characterization of numerous structurally novel and biologically active sesterterpenoids.

A series of novel harmine derivatives bearing a benzylindine substituent in position-1 of β-carboline ring were synthesized and evaluated as antitumor agents. The N2-benzylated β-carboline derivatives 3a–g represented the most interesting anticancer activities and compound 3c was found to be the most active agent to diverse cancer cell lines such as gastric carcinoma, melanoma and colorectal cancer. Notably, compound 3c showed low toxicity to normal cells. The treatment significantly induced cell apoptosis. Mechanistically, PI3K/AKT signaling pathway mediated compound 3c-induced apoptosis. Compound 3c inhibited phosphorylation of AKT and promoted the production of reactive oxygen species (ROS). The ROS scavenger, LNAC and GSH, could disturb the effect of compound 3c induced apoptosis and PI3K activity inhibitor LY294002 synergistically enhanced compound 3c efficacy. Moreover, the results from nude mice xenograft model showed that compound 3c treatment effectively inhibited tumor growth and decreased tumor weight. Collectively, our results demonstrated that compound 3c exerts apoptotic effect in cancer cells via suppression of phosphorylated AKT and evocation of ROS generation, which suggested that compound 3c might be served as a promising therapeutic agent for cancer treatment.

Marine natural products are a rich source of novel and biologically active compounds. The number of identified marine natural compounds has grown 20% over the last five years from 2009 to 2013. Several challenges, including sample collection and structure elucidation, have limited the development of this research field. Nonetheless, new approaches, such as sampling strategies for organisms from extreme ocean environments, nanoscale NMR and computational chemistry for structural determination, are now available to overcome the barriers. In this review, we highlight the experimental technology innovations in the field of marine natural products, which in our view will lead to the development of many new drugs in the future.

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Four new triterpene saponins, ginsenosides Rh(14)-Rh(17)(1- 4), along with two known compounds, 20(S)-ginsenoside Rg₂ and dammar-(E)-20(22),24-diene-3 β,6 α,12 β-triol, were isolated from the stems and leaves of Panax ginseng. The structures of the new compounds were elucidated as 3 β,6 α,12 β,24 ξ-tetrahydroxy-dammar-(E)-20(22),25-diene 6- O- α- L-rhamnopyranosyl-(1 → 2)- β-D-glucopyranoside (1), 3 β,12 β,24 ξ-trihydroxy-dammar-(E)-20(22),25-diene 3- O- β- D-glucopyranosyl-(1 → 2)- β-D-glucopyranoside (2), 3 β,6 α,12 β-trihydroxy-dammar-(E)-20(22),24-diene 3-O-β-D-glucopyranoside (3), and 3-oxo-6 α,12 β,20(S)-trihydroxy-dammar-24-ene 6-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranoside (4) by means of extensive spectroscopic and chemical methods, respectively. The isolated compounds were tested for IN VITRO cytotoxicity against HL-60 cells.

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