Cytotoxic Lignans and Sesquiterpenoids from the Rhizomes of Acorus tatarinowii.

Five new compounds, including a rare phenyldihydronaphthalene lignanamide (1), an unusual hybrid-norlignan derivative (2), a rare cycloheptenone oxide derivative (3), one new acorane-type sesquiterpenoid (4), and one new guaiane-type sesquiterpenoid (5), together with seven known compounds (6-12), have been isolated from the rhizomes of Acorus tatarinowii. The structures of compounds 1-5 were determined by means of extensive spectroscopic methods. To the best of our knowledge, this is first report of a phenyldihydronaphthalene lignanamide and hybrid-norlignan and cycloheptenone oxide derivatives from the genus Acorus. In addition, compound 5 represents the first guaiane-type sesquiterpenoid with an epoxy group located between C-6 and C-9 from natural sources. Compounds 1-12 were evaluated for their in vitro cytotoxicity against five tumor cell lines. Among them, 2, 3, 5, and 10 exhibited moderate cytotoxicity with IC50 values of 2.11-9.23 µM.

LB-1 Exerts Antitumor Activity in Pancreatic Cancer by Inhibiting HIF-1α and Stat3 Signaling.

Hypoxia is widely present in pancreatic cancer and subsequently causes the overexpression of hypoxia-inducible factor-1α (HIF-1α) and signal transducer and activator of transcription-3 (Stat3). HIF-1α and Stat3 function cooperatively to regulate a number of downstream genes that are implicated in tumorigenesis. Thus, inhibition of HIF-1α and Stat3 is a potential therapeutic strategy for pancreatic cancer. In this study, we explored how LB-1, a novel triptolide (LA) derivative, exerted its antitumor effect through blockade of HIF-1α and Stat3 signaling. Our data showed that LB-1 was able to inhibit the proliferation and colony formation of Mia-PaCa2 and SW1990 cells. LB-1 suppressed HIF-1α protein accumulation by promoting its proteasome degradation and reducing transactivation. Moreover, the silence of HIF-1α by shRNA partially prevented the proliferation inhibition triggered by LB-1. As expected, LB-1 also decreased Stat3 protein accumulation and blocked the physical interactions between HIF-1α/p300/phosphor-Stat3 (p-Stat3) at the pharmacological concentration to reduce VEGF expression, thereby hypoxia-induced angiogenesis. In the Mia-PaCa2 nude xenograft model, therapeutic treatment with LB-1 significantly inhibited tumor growth and had minimal systemic toxicity compared to the mother drug LA. Furthermore, in accordance with in vitro results, HIF-1α activation and Stat3 expression in tumors were blocked by LB-1 through mTOR-dependent pathway. Taken together, these results illustrate that, as a potent inhibitor of HIF-1α and Stat3 signaling, LB-1 exhibits antitumor effect and could be potentially used to treat pancreatic cancer.

Cytotoxic taccalonolides and withanolides from Tacca chantrieri.

Six new taccalonolides, taccalonolides AT-AY (1-6), and two new withanolides, chantriolides D and E (7 and 8), together with ten known compounds (9-18), have been isolated from whole plants of Tacca chantrieri. The structures, including the absolute configurations of some of the compounds, were determined by spectroscopic and chemical methods. All compounds were evaluated for their in vitro cytotoxicity against five tumor cell lines. Compounds 9, 10, 13-15, and 17 exhibited cytotoxic activity, with IC50 values of 1.13-5.71 µM, while compound 7 showed selective cytotoxicity. The results indicated that taccalonolides with a six-membered lactone moiety located at C-15 and C-24 were devoid of cytotoxicity against five tumor cell lines (> 10 µM).

An unusual dihydrobenzofuroisocoumarin and ent-kaurane diterpenoids from Pteris multifida.

An unusual 5-C-methylated-dihydrobenzofuroisocoumarin, named multifidarin A (1), and two new ent-kaurane diterpenoids, named multikauranes A (2) and B (3), together with three known ent-kaurane diterpenoids, were isolated from the whole plants of Pteris multifida. The structures of 1-3 were elucidated by spectroscopic methods. The cytotoxic activities of all new compounds were evaluated against five human tumor cell lines. A possible biosynthetic process for the formation of 1 is proposed.

Three New Cytotoxic ent-Kaurane Diterpenes from Isodon excisoides.

Three types of ent-kaurane diterpenoids were isolated from the aerial parts of Isodon excisoides, including three new diterpenoids, 1α,7α,14ß-trihydroxy-20-acetoxy-ent-kaur-15-one (1); 1α,7α,14ß,18-tetrahydroxy-20-acetoxy-ent-kaur-15-one (2); and 1α-acetoxy-14ß-hydroxy-7α,20-epoxy-ent-kaur-16-en-15-one (3); together with six known diterpenes henryin (4); kamebanin (5); reniformin C (6); kamebacetal A (7); kamebacetal B (8); and oridonin (9). The structures of the isolated compounds were elucidated by means of nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry in conjunction with published data for their analogs, as well as their fragmentation patterns. Compounds 5 and 9 were isolated from Isodon excisoides for the first time. To explore the structure-activity relationships of the isolated compounds, they were tested for their cytotoxic effects against five human cancer cell lines: HCT-116, HepG2, A2780, NCI-H1650, and BGC-823. Most of the isolated compounds showed certain cytotoxic activity against the five cancer cell lines with IC50 values ranging from 1.09-8.53 µM. Among the tested compounds, compound 4 exhibited the strongest cytotoxic activity in the tested cell lines, with IC50 values ranging from 1.31-2.07 µM. Compounds 1, 6, and 7 exhibited selective cytotoxic activity.

[The anti-tumor activity and molecular mechanisms of an Aurora kinase inhibitor ZLJ213 in suppressing colon cancer growth].

The aim of this study is to evaluate anti-tumor activities and mechanism of a novel kinase inhibitor ZLJ213 which targeted Aurora A and vascular endothelial growth factor receptor (VEGFR) in vitro and in vivo against human colon cancer. Results showed that ZLJ213 inhibited cell proliferation and induced cell cycle arrest and apoptosis of HCT1 16 and SW48 cell lines. In HCT116-derived xenograft, ZLJ213 dosed at 100 mg · kg(-1) inhibited tumor growth by 73.24%. The IC50 of ZLJ213 on the expression of p-Aurora A was 0.258 µmol · L(-1) analyzed by ELISA. Under the concentration of 0.08 µmol · L(-1), ZLJ213 could inhibit the activities of Aurora A, Histone H3 and VEGFR of HCT116 and SW48 cell lines. Simultaneously, ZLJ213 induced activation of Caspase 3 and PARP cleavage. Above data suggested that ZLJ213 had the ability to inhibit cell proliferation and induce cell apoptosis both in vitro and in vivo in colon cancer, and down-regulate the expression of p-Aurora A and p-VEGFR. ZLJ213 might be a potential therapeutic agent against colon cancer.

[Chemical constituents from Morus notabilis and their cytotoxic effect].

Une new flavonoids named as notabilisin K (1), together with four known compounds, morusin (2), mulberrofuran A (3), neocyclomorusin (4) and mornigrol F (5) are separated from 95% ethanol extracts of the twigs of Morus notabilis. Compounds 2-5 are separated from this plant for the first time. Notabilisin I, notabilisin J exhibits certain effect against cells of HCT-116, HepG2 and A2780 with IC50 values ranging from 1.47 µmol x L(-1) to 5.46 µmol x L(-1). Morusin exhibits strong effect against five kinds of human cancer cells (BGC823, A2780, HCT-116, HepG2 and NCI-H1650) with IC50 values ranging from 0.74 µmol x L(-1) to 1.58 µmol x L(-1).

[Synthesis of novel curcumin mimics and preliminary evaluation for their antitumor activity].

Curcumin has been reported to possess antitumor activity with low toxicity. However, the clinical application of curcumin has been significantly limited by its instability and poor metabolic property. In order to overcome these limitations and discover novel small molecules with potential antitumor activity, 29 curcumin mimics were synthesized, which were confirmed by 1H NMR and HR-MS, and their cytotoxic property was evaluated against five human cancer cell lines in vitro. Compounds 16, 18 and 19 exhibited good cytotoxic property, their IC50 value were even below 5 micromol x L(-1) to some cancer cell lines, 5-9 times better than curcumin.

[Development of a novel screening assay for inhibitors targeting HIF-1alpha and P300 interaction].

Hypoxia is a general characteristic of most solid malignancies and intimately related to cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor-1alpha (HIF-1alpha) that elicits transcriptional activity through recruitment P300 coactivator. Targeting the interaction of HIF- alpha and P300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, a screening assay was developed for inhibitors targeting the interaction between HIF-1alpha and P300. The nucleotide sequence of human HIF-1alpha and P300 were cloned into pBIND and pACT vectors, named pBIND-HIF1alpha and pACT-P300. The interaction of HIF-1alpha and P300 was identified in HEK293 cell using mammalian two-hybrid system. And compound chetomin decreased their interaction in this mammalian two-hybrid system. We further verified HIF-1 inhibition effect of chetomin in U251-HRE cells. Therefore, we established a screening assay combined HIF-1alpha and P300 mammalian two-hybrid system and U251-HRE reporter assay for HIF-1 selective inhibitors.

[Synthesis and in vitro cytotoxic activities of sorafenib derivatives].

A series of novel sorafenib analogues were designed and synthesized. The cytotoxic activities of these compounds were tested in four tumor cell lines. Some of the compounds showed potent antiproliferative activity against the tested cell lines with IC50 = 4-20 micromol x L(-1). Some compounds demonstrated competitive antiproliferative activities to sorafenib against tested cancer cell lines. Among them, compound 7c demonstrated significant inhibitory activities on ACHN, HCT116 and MDA-MB-231 cell lines with IC50 values of 9.01, 4.97, 6.61 micromol x L(-1), respectively.

[Anti-tumor activity and mechanism of T03 in vitro and in vivo].

The purpose of this study is to investigate the activity and mechanism of a new anti-tumor agent T03. MTT and colony formation assay were performed to determine anti-proliferation activity of T03 in vitro. Antitumor activity was observed by Renca xenograft model in vivo. The effect of T03 on cell cycle and apoptosis were measured by FCM analysis. Western blotting was performed to investigate the expression level of proteins in HepG2 cell lines treated with T03. T03 had anti-tumor activity by inhibiting tumor cell growth and colony formation in vitro, especially on hepatocellular carcinoma cells (HCC). At the concentration of 10 micromol x L(-1), T03 induced cell apoptosis and cell cycle arrest in HCC. Moreover, it proved that T03 reduced the tumor weight with the rate of 42.30% without any obviously side effect in Renca xenograft model. At the concentration of 2.0 micromol x L(-1), T03 was able to reduce the level of p-c-Raf (Ser259), and thus blocked Raf/MEK/ERK and AKT signaling in HepG2 cell lines. The result suggested that T03 has the potential to inhibit cell proliferation and induce cell apoptosis both in vitro and in vivo, particularly active against HCC, indicating T03 and its analogues may serve as a new anti-cancer drug against hepatocellular carcinoma.

HMGB1 regulates ferroptosis through Nrf2 pathway in mesangial cells in response to high glucose.

Ferroptosis, a novel type of programmed cell death, is involved in inflammation and oxidation of various human diseases, including diabetic kidney disease. The present study explored the role of high-mobility group box-1 (HMGB1) on the regulation of ferroptosis in mesangial cells in response to high glucose. Compared with healthy control, levels of serum ferritin, lactate dehydrogenase (LDH), reactive oxygen species (ROS), malonaldehyde (MDA), and HMGB1 were significantly elevated in diabetic nephropathy (DN) patients, accompanied with deregulated ferroptosis-related molecules, including long-chain acyl-CoA synthetase 4 (ACSL4), prostaglandin-endoperoxide synthase 2 (PTGS2), NADPH oxidase 1 (NOX1), and glutathione peroxidase 4 (GPX4). In vitro assay revealed that erastin and high glucose both induced ferroptosis in mesangial cells. Suppression of HMGB1 restored cellular proliferation, prevented ROS and LDH generation, decreased ACSL4, PTGS2, and NOX1, and increased GPX4 levels in mesangial cells. Furthermore, nuclear factor E2-related factor 2 (Nrf2) was decreased in DN patients and high glucose-mediated translocation of HMGB1 in mesangial cells. Knockdown of HMGB1 suppressed high glucose-induced activation of TLR4/NF-κB axis and promoted Nrf2 expression as well as its downstream targets including HO-1, NQO-1, GCLC, and GCLM. Collectively, these findings suggest that HMGB1 regulates glucose-induced ferroptosis via Nrf2 pathway in mesangial cells.