Semi-syntheses and interrogation of indole-substituted Aspidosperma terpenoid alkaloids.

We demonstrated here a series of Aspidosperma terpenoid alkaloids can be quickly prepared using semisynthesis from naturally sourced tabersonine, featuring multiple oxygen-based substituents on the indole ring such as hydroxy and methoxy groups. This panel of complex compounds enabled the exploration of indole modifications to optimize the indole alkaloids' anticancer activity, generating lead compounds (e.g., with C15-hydroxy, C16-methoxy, and/or C17-methoxy derivatizations) that potently inhibit cancer cell line growth in the single-digit micromolar range. These results can help guide the development of Aspidosperma terpenoid alkaloid therapeutics. Furthermore, this synthetic approach features late-stage facile derivatization on complex natural product molecules, providing a versatile path to indole derivatization of this family of alkaloids with diverse chemical functionalities for future medicinal chemistry and chemical biology discoveries.

Discovery of an Orally Active and Liver-Targeted Prodrug of 5-Fluoro-2'-Deoxyuridine for the Treatment of Hepatocellular Carcinoma.

We report a series of novel O-(substituted benzyl) phosphoramidate prodrugs of 5-fluoro-2'-deoxyuridine for the treatment of hepatocellular carcinoma. Through structure optimization, the o-methylbenzyl analog (1t) was identified as an orally bioavailable and liver-targeted lead compound. This lead prodrug is well-tolerated at a dose up to 3 g/kg in Kuming mice via oral administration. An efficacy study demonstrated that it possesses good inhibitory effect (61.67% and 72.50%, respectively) on tumor growth in a mouse xenograft model. A metabolism study in Sprague-Dawley rats suggested that 1t can release the desired 5'-monophosphate in the liver with high liver-targeting index.

Design, synthesis, and biological evaluation of new N(4)-Substituted 2'-deoxy-2'-fluoro-4'-azido cytidine derivatives as potent anti-HBV agents.

A series of new 2'-deoxy-2'-ß-fluoro-4'-azido-ß-d-arabinofuranosyl cytidine derivatives bearing heteroatom-containing N(4)-substituents were designed and synthesized. Antiviral screening in HepG2.2.15 cells identified three analogs (1a, 1d &1g) with good anti-HBV activity and low cytotoxicty. Of them, compound 1g exhibited significant inhibitory activity on both HBV antigens secretion (EC50, HBsAg = 9 nM, EC50, HBeAg = 0.25 µM) and viral DNA replication (intracellular, EC50 = 0.099 µM; extracellular, EC50 < 0.01 µM).

Synthesis and biological evaluation of 4-substituted fluoronucleoside analogs for the treatment of hepatitis B virus infection.

A series of 4-substituted fluoronucleosides have been synthesized in order to address the toxicity issue of the parent compound 7, and after in vitro evaluation, the cyclopropylamino analog 1f was selected for in vivo study. In mice, this compound exhibited a significantly improved toxicity profile. Administered orally, compound 1f was well-tolerated at a dose up to 3 g/kg and showed insignificant toxicity on white blood cells and a low mutagenic effect at dosages up to 80 mg/kg (single) or 20 mg/kg/day (5 days). In duck HBV (DHBV)-infected duck models, both the serum and liver DHBV DNA levels (74.2 and 82.1%, respectively) were markedly reduced by the treatment of 1f at a dose of 1 mg/kg/day for 10 days. In addition, both the viral DNA levels had a lower degree of recovery after withdrawal of the test compound for 3 days.

Drug-induced apoptosis of Echinococcus granulosus protoscoleces.

Parasitic infection by Echinococcus granulosus in humans induces hydatidosis (echinococcosis), which is a zoonotic disease that seriously endangers public health. This study was to determine the status of cell apoptosis in the protoscoleces of E. granulosus, which were isolated from hydatid cysts in livers or lungs of sheep. Those protoscoleces were incubated with drugs (at the concentration of 1 mmol L(-1) H(2)O(2) and 5 mmol L(-1)dexamethasone) for 8 h, the apoptosis were examined by transmission electron microscopy and TUNEL assay, the expression of caspase-1 and caspase-3 were detected by immunohistochemistry and caspase-3 activity was detected by colorimetric assay. Our results have clearly demonstrated the presence of cell apoptosis in protoscoleces in the absence or presence of drug (H(2)O(2), dexamethasone) treatment, but drug-induced apoptosis rate, caspase-1 and caspase-3 expression levels were higher than no-drug induce and caspase-3 activity were significantly increasing. We found H(2)O(2) and dexamethasone can induce the cell apoptosis of protoscoleces. Our results implied the existence of a CED-3 like apoptosis gene in protoscolces and provide a rationale for further exploring the induction of apoptosis as non-surgical treatment method in treating this parasitic disease.

[Apoptosis induced in vitro by dexamethasone and ATP in the protoscolex of Echinococcus granulosus].

OBJECTIVE: To explore the apoptosis induced by dexamethasone and adenosine triphosphate (ATP) in protoscolex of Echinococcus granulosus. METHODS: Protoscoleces were cultured in vitro and used for the experiment in 4 groups: dexamethasone (5 mmol/L) group, ATP (1.6 mmol/L) group, dexamethasone (5 mmol/L)+ATP (1.6 mmol/L) group, and RPMI 1640 medium as control group. The morphology of protoscolex was observed by light microscopy. After drug treatment for 8 h, the group with significant morphological changes in protoscolex was selected to observe the ultrastructure of protoscolex by transmission electron microscopy. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay (TUNEL) was employed to observe the apoptosis. Caspase-3 activity was detected with a kit, and DNA fragments were seperated by agarose gel electrophoresis. RESULTS: After induced for 8 h, the protoscoleces shrank in dexamethasone group and dexamethasone+ATP group, the rostellum was invaginated. Compared with the control, the calcareous corpuscles in the protoscolex significantly reduced and blurred in the two groups The morphological changes in protoscolex of dexamethasone+ATP group was more obvious than that of dexamethasone group. Electron microscopy showed that dexamethasone+ATP-treated protoscoleces possessed typical morphological features of apoptosis, including the cell volume reduction with densified cytoplasm, cell membrane blebbing, and nuclear heterochromatin peripheral aggregation below the nuclear membrane. A few apoptotic cells were found in protoscolex of dexamethasone+ATP group by TUNEL, while none in the control. Caspase-3 activity significantly increased 12-fold compared to the control. About 150 bp DNA fragment exhibited the typical DNA ladder formation characteristic for apoptosis in dexamethasone+ATP group. CONCLUSION: Apoptosis in the protoscolex of E. granulosus may be induced by dexamethasone and ATP in vitro.