A photoinduced intramolecular cyclization of allyl acrylates to synthesize fully substituted spiro-γ-butyrolactone compounds is described. The reaction is believed to proceed through an intramolecular hydrogen abstraction strategy.

Rubriflordilactones A (1) and B (2), two novel highly unsaturated rearranged bisnortriterpenoids possessing a biosynthetically modified aromatic D-ring, were isolated from the leaves and stems of Schisandra rubriflora. Their structures were established on the basis of extensive spectroscopic methods, including two-dimensional NMR techniques, and confirmed by X-ray crystallographic analysis. Compound 1 showed weak anti-HIV-1 activity, and compound 2 exhibited an EC50 value of 9.75 microg/mL (SI=12.39) against HIV-1 replication with low cytotoxicity.

PURPOSE:Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive squamous cell carcinomas and is generally resistant to chemotherapy. In the present study, the cytotoxic activity of Rabdocoestin B (Rabd-B) against ESCC and the underlying mechanisms were investigated.METHODS:The inhibitory effect of Rabd-B on KYSE30 and KYSE450 was evaluated by Cell Counting Kit-8 (CCK8) and colony formation assays in vitro. The cell cycle distribution and apoptosis of cells treated with Rabd-B were determined by flow cytometry. The mechanisms underlying the effects of Rabd-B were systematically examined by Western blot. The in vivo anti-tumor ability of Rabd-B was measured in mouse xenograft models and cisplatin (DDP) was used as positive control.RESULTS:Rabd-B efficiently induced G2/M phase arrest in ESCC cells by upregulating the Chk1/Chk2-Cdc25C axis to inhibit the G2→M transition facilitated by Cdc2/Cyclin B1. Furthermore, Rabd-B suppressed ATM/ATR phosphorylation, thereby inhibiting BRCA1-mediated DNA repair, which resulted in mitotic catastrophe and induced cell apoptosis. Rabd-B also decreased the activity of the Akt and NF-κB survival signaling pathways and ultimately initiated the caspase-9-dependent intrinsic apoptotic pathway in ESCC cells. The apoptosis induced by Rabd-B could be partially reversed by a caspase-9-specific inhibitor (Z-LEHD-FMK) and a pan-caspase inhibitor (Z-VAD-FMK). Moreover, Rabd-B effectively suppressed tumor growth in mouse xenografts which was comparable to that of DDP without significant injuries to the mice.CONCLUSION:Taken together, these findings indicate that Rabd-B is a promising precursor compound that may be useful as a treatment for ESCC and thus warrants further investigation.

Autophagy is an intracellular lysosomal/vacuolar degradation system, in which the inner cytoplasmic cell membrane is degraded by the lysosomal hydrolases, followed by the resulting products released back into the cytosol. It is involved in many physiological processes which are crucial for cell growth and survival. However, disturbance in the autophagic process is often associated with a variety of human diseases, such as cancer. Breast cancer is one of the most malignant tumors characterized by the imbalanced cell proliferation, apoptosis as well as disordered autophagy regulation. The alterations of autophagy related genes or protein levels in breast cancer cells also suggested a potential implication of autophagy in breast cancer development and progression. Many natural products had been reported as potential anti-cancer agents or being considered as direct or indirect sources of new chemotherapy adjuvants to enhance the efficacy or to ameliorate the side effects through the modulation of autophagy. Investigation of the underlying mechanism of these compounds could be crucial for the development of new therapeutic or chemopreventive options for breast cancer treatment. In this review, a summary of those natural products that can regulate autophagy in breast cancer is presented and the potential value of such autophagy modulators on the development of anti-cancer drugs is also discussed.

BACKGROUND:Pancreatic cancer, associated with poor prognosis and low survival rate, has been the fourth leading cause of cancer-related death in the US. Although gemcitabine (Gem) is the first-line chemotherapeutic drug in the management of pancreatic cancer, the median survival extension is only 1.5 months, indicating unsatisfactory clinical results. Therefore, exploring agents that can enhance the anti-cancer activity of Gem would be an attractive strategy.PURPOSE:Our previous studies have demonstrated that eriocalyxin b (EriB), an ent‑kaurane diterpenoid isolated from Isodon eriocalyx (Dunn.) Hara, possesses anti-pancreatic cancer effects, thus acting as a potential therapeutic agent. In this study, we further investigated whether EriB or the ethanol extract of I. eriocalyx (Isodon) could potentiate the cytotoxic activity of Gem in human pancreatic adenocarcinoma cells. In addition, the mechanism associated with their effects was also studied.METHODS:The anti-proliferation effect was assessed by MTT assay and Ki-67 immunostaining. The combination effect (addition, synergism and antagonism) of various agents was calculated by the Calcusyn software (Biosoft), utilizing the T.C. Chou Method. Apoptosis was detected using Annexin V and PI double staining followed by quantitative flow cytometry. Protein expression regulated by various treatments was analyzed by western blotting.RESULTS:The combination index revealed that Gem and EriB (or Isodon extract) had synergistic anti-proliferative effect. Both cellular apoptotic and anti-proliferative effects of Gem were significantly increased after combination with EriB (or Isodon extract). The underlying mechanisms involved in the combination effects were elucidated, which include: (1) increased activation of the caspase cascade; (2) reduction of PDK1 and AKT phosphorylation; (3) induction of JNK phosphorylation by Isodon and Gem combination.CONCLUSION:Gem and EriB (or Isodon extract) taken together in combination regulated PDK1/AKT1/caspase and JNK signaling and promoted apoptosis synergistically, which may contribute to the much increased anti-proliferative activity compared to either agent alone.

Four new ent-kaurene diterpenoids, phyllostachysins M-P (1-4) have been isolated from the aerial parts of Isodon phyllostachys. Compound 1 features a novel dihydro-2H-pyran ring motif, which was formed by an unusual cleavage in ring-A. 2 and 3 bear a rare 20-nor-ent-kaurene structure, but 4 has a rare 7,20cyclo-ent-kaurene skeleton. Their structures were elucidated on the basis of extensive spectroscopic analyses. Compounds 1, 3, and 4 were evaluated for their cytotoxic activity against five human tumor cell lines. (C) 2016 Published by Elsevier Ltd.

The phytochemical investigation on 1 g of materials from Gypsoplacamacrophylla (Zahlbr.) Timdal resulted in the discovery of gypmacrophin A, a rare pentacyclic sesterterpenoid; brialmontin III, a new polysubstituted depside and two known ones, brialmontins I and II. The structure and absolute configurations of gypmacrophin A were elucidated by spectroscopic analyses and computational methods. Gypmacrophin A showed weak inhibition of AchE with an IC50 value of 32.03 μM. The four compounds provided new chemical evidence for G. macrophylla identification.

Peroxiredoxin1 (PRDX1) is overexpressed in medulloblastoma (MBL) causing resistance to therapy. Adenanthin (PRDX1 inhibitor) had been validated as a therapeutic target in MBL. However, adenanthin does not cross the blood-brain barrier (BBB). The objective of this study was to examine the efficacy of adenanthin in conjunction with Hav peptide (to transiently modulate the BBB) in an MBL tumor model. Effects of HAV6 on BBB permeability to gadolinium contrast-agent (Gd-DTPA) and adenanthin were examined in healthy mice using MRI and LC/MS respectively. The response of MBL tumor mice to adenanthin was also examined under control conditions and following the BBB disruption using HAV6. Brain tumors in mice were induced by stereotaxic injection of D425 tumor cells. A 5-cycle treatment regimen began 10 days following tumor induction. For each cycle, the mice received 3-consecutive days of either vehicle, adenanthin (10mg/kg), or a combination of adenanthin (10mg/kg) and Hav (0.010mmol/kg) peptide followed by a 1 day of rest. The mice were then monitored for signs of tumor progression. Under control conditions, very little Gd-DTPA and adenanthin entered the brain. In contrast, mice treated with HAV6 showed a significant increase of BBB permeability to both Gd-DTPA (3-fold) and adenanthin (100-fold) compared to control. All mice injected with D425 cells developed tumors within 7 days as seen by bioluminescence imaging. Tumor volume increased at similar rate with median survival of 16 and 18 days for placebo and adenanthin treatment groups respectively. In contrast, tumor bearing mice treated with the combination of Hav and adenanthin showed significant reduction in tumor size and extended survival (>32 days) with little to no symptoms of tumor burden or toxicity related to treatment. Transient disruption of BBB using HAV6 provided therapeutically relevant adenanthin brain concentrations, thereby improving the response to treatment in tumor bearing mice.

Group-3 Medulloblastomas (MBL) has the worst prognosis due to its resistance to radiation and chemotherapy with a 5-year survival of 30%. Thus, there is an urgent need to elucidate targets that can sensitize Group-3 tumors to conventional treatments. We identified PRDX1 as a candidate therapeutic target for therapy sensitization in group-3 tumors. PRDX1 catalyzes the conversion of hydrogen peroxide to water and oxygen. We hypothesized that inhibiting PRDX1 would lead to oxidative stress and increase susceptibility to ionizing radiation via extensive DNA damage. Accordingly, when PRDX1 was targeted using Adenanthin (specific chemical inhibitor) or RNAi, Group-3 MBL (D425-MED) cells were rendered hypersensitive to radiation. Mechanistically, targeting PRDX1 resulted in an increase in reactive oxygen species, extensive oxidative DNA damage and an induction of the apoptotic pathway. Similarly, overexpression of PRDX1 in MBL cells susceptible to radiation (DAOY, UW-228) resulted in radiation resistance. However targeting PRDX1 in normal astrocytes did not have any sensitization effects. The in-vitro results were validated in-vivo using flank tumors (Adenanthin) and an orthotopic murine model (both RNAi and Adenanthin) using Group-3 MBL cells (D425-MED) and patient derived xenografts (MB3W1). Briefly, mice bearing Group-3 MBL tumors (D425-MED / MB3W1) when subjected to treatment with Adenanthin combined with radiation achieved a synergistic increase in survival. To fully evaluate the therapeutic potential of PRDX1 across all groups of MBL, we determined the expression of PRDX1 in a validated MBL tumor micro-array (TMA) by immunohistochemistry and correlated it with patient characteristics, therapeutic response and clinical outcomes. We also evaluated the role of PRDX1 in Group-3 MBL stem cells with respect to radiation resistance, invasion and migration. The results from these experiments will be presented in the meeting. Our data suggest that PRDX1 is a therapeutic target in Group-3 MBL and Adenanthin as a small molecule inhibitor of PRDX1.

Fourteen new diterpenoids (1-14) based on four skeletal types and two known analogues (15 and 16) were isolated from the aerial parts of Isodon scoparius. Compound 2 is the first ent-kaurane diterpenoid featuring a 1,11-ether bridge, and the structures of these new compounds were established mainly by NMR and MS methods. The absolute configurations of 1 and 5 and the relative configuration of 3 were determined using single-crystal X-ray diffraction. The absolute configuration of 14 was determined by comparison of the experimental and calculated electronic circular dichroism spectra. Compounds 1, 4, and 15 were active against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW-480), and they also inhibited NO production in LPS-stimulated RAW264.7 cells, with IC50 values of 1.0, 3.1, and 1.8 mu M, respectively.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Group-3 medulloblastoma (MBL) is highly resistant to radiation (IR) and chemotherapy and has the worst prognosis. Hence, there is an urgent need to elucidate targets that sensitize these tumors to chemotherapy and IR. Employing standard assays for viability and sensitization to IR, we identified PRDX1 as a therapeutic target in Group-3 MBL. Specifically, targeting PRDX1 by RNAi or inhibition by Adenanthin led to specific killing and sensitization to IR of Group-3 MBL cells. We rescued sensitization of Daoy and UW228 cells by hypermorphic expression of PRDX1. PRDX1 knockdown caused oxidative DNA damage and induced apoptosis. We correlated PRDX1 expression to patient outcomes in a validated MBL tumor-microarray. Whole genome sequencing identified pathways/genes that were dysregulated with PRDX1 inhibition or silencing. Our in vivo studies in mice employing flank/orthotopic tumors from patient derived xenografts/Group-3 MBL cells confirmed in vitro observations. Animals with tumors in which PRDX1 was targeted by RNAi or Adenanthin (using mini osmotic pumps) showed decreased tumor burden and increased survival when compared to controls. Since, Adenanthin does not cross the blood brain barrier (BBB) we used HAV6 peptide to transiently disrupt the BBB and deliver Adenanthin to the tumor. Immunohistochemistry confirmed that targeting PRDX1 resulted in increased oxidative DNA damage, apoptosis and decreased proliferation. In summary, we have validated PRDX1 as a therapeutic target in group-3 MBL, identified Adenanthin as a potent chemical inhibitor of PRDX1 and confirmed the role of HAV peptide (in the transient modulation of BBB permeability) in an orthotopic model of group-3 MBL.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Effective treatments for esophageal squamous cell carcinoma (ESCC), one of the most common cancers in China, are lacking. Longikaurin A (LK-A), an ent-kauranoid diterpenoid isolated from Isodon ternifolius, has been shown to have potent cytotoxic effects on ESCC cells both in vivo and in vitro, mainly by inducing apoptosis. In this study, LK-A inhibited ESCC cells viability and induced G2/M cell cycle arrest. Moreover, LK-A was also highly effective in a KYSE-30 xenograft nude mouse model. Treatment with Z-VAD(OMe)-FMK partially attenuated LK-A-induced apoptosis. LK-A significantly induced reactive oxygen species (ROS) production in ESCC cells, and LK-A-induced apoptosis was attenuated by the ROS scavenger N-acetyl cysteine (NAC). Furthermore, we found that treatment with LK-A activated both the JNK and p38 MAPK signaling pathways, resulting in increases in ROS levels and apoptosis induction. Taken together, these findings indicate that LK-A exerts novel anti-tumor effects in ESCC cells by activating the JNK and p38 MAPK pathways and inducing increases in ROS production, which suggest that the compound may have potential as a clinical therapeutic agent.

On the basis of One Strain/Many Compounds (OSMAC) strategy, five new polyketides, named phomopsiketones A-C (1-3), (10S)-10-O-beta-D-4'-methoxymannopyranosyldiaporthin (7), and clearanol H (10), and two new natural products, 4 and 5, along with three known ones, 6, 8 and 9, were isolated from an endophytic fungus, Phomopsis sp. sh917, harbored in stems of Isodon eriocalyx var. laxiflora. Their structures were elucidated by spectroscopic methods. The absolute configurations of 1, 3, and 7 were further confirmed by single crystal X-ray diffraction experiment. Compounds 2, 4, 6, 9 and 10 were assigned absolute configurations on the basis of circular dichroism (CD) or optical rotation (OR) data comparison. In addition, antiangiogenic activity of compounds 2, 3, 5, and 6 were evaluated by using human umbilical vascular endothelial cells (HUVECs) in a cell-culture model of angiogenesis. Especially, compound 6 sufficiently inhibited vascular endothelial growth factor(VEGF)-induced angiogenic processes in vitro, including migration, invasion, and tube formation of HUVECs. (C) 2017 Elsevier Ltd. All rights reserved.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

as a therapeutic target in Group-3 MBL. Specifically, targeting PRDX1 by RNAi or inhibition by Adenanthin led to specific killing and sensitization to IR of Group-3 MBL cells. We rescued sensitization of Daoy and UW228 cells by hypermorphic expression of PRDX1. PRDX1 knockdown caused oxidative DNA damage and induced apoptosis. We correlated PRDX1 expression to patient outcomes in a validated MBL tumor-microarray. Whole genome sequencing identified pathways/genes that were dysregulated with PRDX1 inhibition or silencing. Our in vivo studies in mice employing flank/orthotopic tumors from patient derived xenografts/Group-3 MBL cells confirmed in vitro observations. Animals with tumors in which PRDX1 was targeted by RNAi or Adenanthin (using mini osmotic pumps) showed decreased tumor burden and increased survival when compared to controls. Since, Adenanthin does not cross the blood brain barrier (BBB) we used HAV6 peptide to transiently disrupt the BBB and deliver Adenanthin to the tumor. Immunohistochemistry confirmed that targeting PRDX1 resulted in increased oxidative DNA damage, apoptosis and decreased proliferation. In summary, we have validated PRDX1 as a therapeutic target in group-3 MBL, identified Adenanthin as a potent chemical inhibitor of PRDX1 and confirmed the role of HAV peptide (in the transient modulation of BBB permeability) in an orthotopic model of group-3 MBL.

This review focuses on new diterpenoids from theIsodonspecies, including their structures, classifications, biogenetic pathways, bioactivities, and chemical synthesis (from December 2005 to June 2016).

Four new ent-abietane diterpenoids, along with four known ones were isolated from the aerial parts of Isodon serra, a traditional Chinese folk medicine. The new diterpenoids were named as serrin K (1), xerophilusin XVII (2), and enanderianins Q and R (3 and 4), while the known ones were identified as rubescansin J (5), (3α,14β)-3,18-[(1-methylethane-1,1-diyl)dioxy]-ent-abieta-7,15(17)-diene-14,16-diol (6), xerophilusin XIV (7), and enanderianin P (8), respectively. Their structures were elucidated by extensive spectroscopic analysis and comparison with the literature. Compound 1 showed remarkable inhibitory activity towards NO production in LPS-stimulated RAW264.7 cells (IC50 = 1.8 μM) and weak cytotoxicity towards five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, SW480).