The Marine-Derived Oligosaccharide Sulfate (MdOS), a Novel Multiple Tyrosine Kinase Inhibitor, Combats Tumor Angiogenesis both In Vitro and In Vivo

Despite the emerging success of multi-targeted protein tyrosine kinase (PTK) inhibitors in cancer therapy, significant side effects and resistance concerns seems to be avoided unlikely. The aim of the present study was to identify novel multi-targeting PTK inhibitors. The kinase enzymatic activities were measured by enzyme-linked immunosorbent assay (ELISA). The antiproliferative activities in human microvascular endothelial cells (HMECs) were evaluated by sulforhodamine (SRB) assay. The phosphorylation of kinases and their downstream molecules was probed by western blot analysis. The binding mode between MdOS and PTKs was profiled by surface plasmon resonance (SPR) approach and molecular simulation. Tube formation assay, rat aortic ring method and chicken chorioallantoic membrane assay were combined to illustrate the in vitro and in vivo anti-angiogenic effects. Results indicated that MdOS, a novel marine-derived oligosaccharide sulfate, exhibited a broad-spectrum PTK inhibitory action. At an enzymatic level, MdOS inhibited HER2, EGFR, VEGFR, PDGFR, c-Kit, FGFR1 and c-Src, with little impact on FGFR2. In cellular settings, MdOS inhibited phosphorylation of PTKs, exemplified by HER2, EGFR and VEGFR2, and downstream molecules of Erk1/2 and AKT. Further studies demonstrated that MdOS acted as an ATP-competitive inhibitor via directly binding to the residues of entrance rather than those of the ATP-binding pocket. Furthermore, MdOS inhibited proliferation and tube formation of HMECs, arrested microvessel outgrowth of rat aortic rings and hindered the neovascularization of chick allantoic membrane. Taken together, results presented here indicated that MdOS exhibited anti-angiogenic activity in a PTK-dependent manner and make it a promising agent for further evaluation in PTK-associated cancer therapy

AST1306, A Novel Irreversible Inhibitor of the Epidermal Growth Factor Receptor 1 and 2, Exhibits Antitumor Activity Both In Vitro and In Vivo

Despite the initial response to the reversible, ATP-competitive quinazoline inhibitors that target ErbB-family, such a subset of cancer patients almost invariably develop resistance. Recent studies have provided compelling evidence that irreversible ErbB inhibitors have the potential to override this resistance. Here, we found that AST1306, a novel anilino-quinazoline compound, inhibited the enzymatic activities of wild-type epidermal growth factor receptor (EGFR) and ErbB2 as well as EGFR resistant mutant in both cell-free and cell-based systems. Importantly, AST1306 functions as an irreversible inhibitor, most likely through covalent interaction with Cys797 and Cys805 in the catalytic domains of EGFR and ErbB2, respectively. Further studies showed that AST1306 inactivated pathways downstream of these receptors and thereby inhibited the proliferation of a panel of cancer cell lines. Although the activities of EGFR and ErbB2 were similarly sensitive to AST1306, ErbB2-overexpressing cell lines consistently exhibited more sensitivity to AST1306 antiproliferative effects. Consistent with this, knockdown of ErbB2, but not EGFR, decreased the sensitivity of SK-OV-3 cells to AST1306. In vivo, AST1306 potently suppressed tumor growth in ErbB2-overexpressing adenocarcinoma xenograft and FVB-2/Nneu transgenic breast cancer mouse models, but weakly inhibited the growth of EGFR-overexpressing tumor xenografts. Tumor growth inhibition induced by a single dose of AST1306 in the SK-OV-3 xenograft model was accompanied by a rapid (within 2 h) and sustained (≥24 h) inhibition of both EGFR and ErbB2, consistent with an irreversible inhibition mechanism. Taken together, these results establish AST1306 as a selective, irreversible ErbB2 and EGFR inhibitor whose growth-inhibitory effects are more potent in ErbB2-overexpressing cells

Design, Synthesis, and Evaluation of Ribose-Modified Anilinopyrimidine Derivatives as EGFR Tyrosine Kinase Inhibitors

The synthesis of a series of ribose-modified anilinopyrimidine derivatives was efficiently achieved by utilizing DBU or tBuOLi-promoted coupling of ribosyl alcohols with 2,4,5-trichloropyrimidine as key step. Preliminary biological evaluation of this type of compounds as new EGFR tyrosine kinase inhibitors for combating EGFR L858R/T790M mutant associated with drug resistance in the treatment of non-small cell lung cancer revealed that 3-N-acryloyl-5-O-anilinopyrimidine ribose derivative 1a possessed potent and specific inhibitory activity against EGFR L858R/T790M over WT EGFR. Based upon molecular docking studies of the binding mode between compound 1a and EGFR, the distance between the Michael receptor and the pyrimidine scaffold is considered as an important factor for the inhibitory potency and future design of selective EGFR tyrosine kinase inhibitors against EGFR L858R/T790M mutants

Transcriptome and Metabolome Integration Reveals the Impact of Fungal Elicitors on Triterpene Accumulation in <i>Sanghuangporus sanghuang</i>

Sanghuangporus sanghuang is a large wood-decaying mushroom highly valued in traditional Chinese medicine due to its medicinal properties, including hypoglycemic, antioxidant, antitumor, and antibacterial properties effects. Its key bioactive compounds include flavonoids and triterpenoids. Specific fungal genes can be selectively induced by fungal elicitors. To investigate the effect of fungal polysaccharides derived from Perenniporia tenuis mycelia on the metabolites of S. sanghuang, we conducted metabolic and transcriptional profiling with and without elicitor treatment (ET and WET, respectively). Correlation analysis showed significant differences in triterpenoid biosynthesis between the ET and WET groups. In addition, the structural genes associated with triterpenoids and their metabolites in both groups were verified using quantitative real-time polymerase chain reaction (qRT-PCR) and high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Through metabolite screening, three triterpenoids were identified: betulinol, betulinic acid, and 2-hydroxyoleanolic acid. Excitation treatment increased the level of betulinic acid by 2.62-fold and 2-hydroxyoleanolic acid by 114.67-fold compared to WET. The qRT-PCR results of the four genes expressed in secondary metabolic pathways, defense gene activation, and signal transduction showed significant variation between the ET and WET groups. Overall, our study suggests that the fungal elicitor induced the aggregation of pentacyclic triterpenoid secondary metabolites in S. sanghuang

Structure of MdOS.

<p>Structure of MdOS.</p

Ventricular Morphology and Outcomes in Fontan Circulation without Hypoplastic Left Heart Syndrome: A Single-Center's Experience

Background: The impact of dominant ventricular morphology on Fontan patient outcomes remain controversial. This study evaluates long-term results of right ventricle (RV) dominance versus left ventricle (LV) dominance in Fontan circulation without hypoplastic left heart syndrome (HLHS). Methods: We retrospectively examined 323 Fontan operations from our center. To minimize pre- and intra-Fontan heterogeneity, 42 dominant RV patients were matched with 42 dominant LV patients using propensity score matching, allowing for a comparative analysis of outcomes between groups. Results: The mean follow-up was 8.0 ± 4.6 years for matched RV dominant and 6.5 ± 4.7 years for matched LV dominant group (p > 0.05), showing no significant difference. The cumulative incidence of moderate or greater atrioventricular valve regurgitation was also comparable between the two groups (p > 0.05). Similarly, 10-year freedom from death or transplantation following the Fontan operation was 84% ± 7% in the matched dominant RV group, similar to 81% ± 7% in the matched dominant LV group (p > 0.05). The 10-year freedom from Fontan failure was 78% ± 8% in the matched dominant RV group, also similar to 75% ± 8% in the matched dominant LV group (p >0.05). Multivariate analysis did not identify RV dominance as a risk factor for Fontan failure (p > 0.05). Conclusions: In the pre- and intra-Fontan context, RV dominance demonstrated similar and comparable long-term outcomes compared to LV dominance in non-HLHS Fontan circulation

MdOS directly targets intracellular tyrosine kinase.

<p>A, Cell entry and location of MdOS. SK-OV-3 cells were treated as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0003774#s4" target="_blank">materials and methods</a>, and photographed by Leica TCS confocal microscope. Bar, 10 µm. B, <i>Left</i>, starved SK-OV-3 cells were incubated with 100 µg/ml MdOS for 6 h, followed by stimulated with EGF directly or washed three times with serum-free medium then stimulated with EGF (+w). <i>Right</i>, SK-OV-3 cells were plated in six-well plates. 24 h after plating, medium was replaced with serum-free medium supplemented with indicated concentrations of MdOS for 6 h.</p

Predictive interaction between MdOS and VEGFR2 or EGFR by molecular docking.

<p>A, binding mode of MdOS and VEGFR2 kinase (PDB code: 1YWN). B, the detailed binding interactions between MdOS and VEGFR2 kinase. Hydrogen bonds are indicted by dashed lines. C, binding mode of MdOS and EGFR kinase (PDB code: 1XKK). D, the detailed binding interactions between MdOS and EGFR kinase. Hydrogen bonds are indicted by dashed lines.</p

Lineweaver Burke plot of ATP competition.

<p>VEGFR2 (A) and HER-2 (B) and EGFR (C) kinase assays were performed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0003774#s4" target="_blank">Materials and Methods</a> in the presence of varying concentrations of ATP. Initial reaction velocity was expressed as the phosphorylation of poly(Glu, Tyr)_4∶1 substrate. All x, y data sets were multiplied by 100 for purposes of graphical presentation.</p