Design, synthesis and evaluation of novel bis-substituted aromatic amide dithiocarbamate derivatives as colchicine site tubulin polymerization inhibitors with potent anticancer activities.

As the continuation of our work on the development of tubulin inhibitors with potential anticancer activities, novel bis-substituted aromatic amide dithiocarbamate derivatives were designed by contacting bis-substituted aryl scaffolds (potential anti-tubulin fragments) with N-containing heterocycles (potential anti-tubulin fragments) in one hybrid using the anticancer dithioformate unit as the linker. The antiproliferative activity against three digestive tract tumor cells was evaluated and preliminary structure activity relationships were summarized. Among these compounds, compound 20q exhibited most potent antiproliferative activity against MGC-803, HCT-116, Kyse30 and Kyse450 cells with IC50 values of 0.084, 0.227, 0.069 and 0.078 µM, respectively. In further studies, compound 20q was identified as a novel tubulin inhibitor targeting the colchicine binding site. Compound 20q could inhibit the microtubule assembly and disrupt cytoskeleton in Kyse30 and Kyse450 cells. The results of molecular docking suggested that compound 20q could tightly bind into the colchicine binding site of tubulin by hydrogen bonds and hydrophobic interactions. Compound 20q dose-dependently inhibited the cell growth and colony formation, effectively arrested cells at the G2/M phase and induce mitochondrial apoptosis in Kyse30 and Kyse450 cells. In addition, Compound 20q could regulate the expression of G2/M phase and mitochondrial apoptosis related proteins. Collectively, compound 20q was here reported as a novel tubulin inhibitor with potential anticancer activities.

Prefrontal Nectin3 Reduction Mediates Adolescent Stress-Induced Deficits of Social Memory, Spatial Working Memory, and Dendritic Structure in Mice.

Chronic stress may disrupt the normal neurodevelopmental trajectory of the adolescent brain (especially the prefrontal cortex) and contribute to the pathophysiology of stress-related mental illnesses, but the underlying molecular mechanisms remain unclear. Here, we investigated how synaptic cell adhesion molecules (e.g., nectin3) are involved in the effects of adolescent chronic stress on mouse medial prefrontal cortex (mPFC). Male C57BL/6N mice were subjected to chronic social instability stress from postnatal days 29 to 77. One week later, the mice exposed to chronic stress exhibited impaired social recognition and spatial working memory, simplified dendritic structure, and reduced spine density in the mPFC. Membrane localization of nectin3 was also altered, and was significantly correlated with behavioral performance. Furthermore, knocking down mPFC nectin3 expression by adeno-associated virus in adolescent mice reproduced the stress-induced changes in behavior and mPFC morphology. These results support the hypothesis that nectin3 is a potential mediator of the effects of adolescent chronic stress on prefrontal structural and functional abnormalities.

Synthesis and in vitro biological evaluation of novel derivatives of Flexicaulin A condensation with amino acid trifluoroacetate.

As our research focus on anticancer drugs, two series of novel derivatives of Flexicaulin A (FA), an ent-kaurene diterpene, condensation with amino acid trifluoroacetate were synthesized, and their anti-proliferative activity against four human cancer cell lines (TE-1, MCF-7, A549 and MGC-803) were evaluated. Compared with FA, the anticancer activity and solubility of most derivatives were significantly improved. Among them, compound 6d had the best activity, and its IC50 value against Esophageal cancer cells (TE-1) was up to 0.75 µM. Subsequent cellular mechanism studies showed that compound 6d could inhibit the proliferation of cancer cells, the formation of cell colonies, and increase the level of ROS on TE-1 cells. In addition, 6d could up-regulate the expressions of SAPK/JNK pathway-associated proteins (p-ASK1, p-MKK4 and p-JNK) and pro-apoptotic proteins (Bak, Bad and Noxa), remarkably increase the ratio of Bax to Bcl-2 and activate Cleaved Caspase-3/9/PARP. These results indicate that compound 6d induces apoptosis through the ROS/JNK/Bcl-2 pathway and holds promising potential as an anti-proliferative agent.

GAS1 Deficient Enhances UPR Activity in Saccharomyces cerevisiae.

Beta-1,3-glucanosyltransferase (Gas1p) plays important roles in cell wall biosynthesis and morphogenesis and has been implicated in DNA damage responses and cell cycle regulation in fungi. Yeast Gas1p has also been reported to participate in endoplasmic reticulum (ER) stress responses. However, the precise roles and molecular mechanisms through which Gas1p affects these responses have yet to be elucidated. In this study, we constructed GAS1-deficient (gas1Δ) and GAS1-overexpressing (GAS1 OE) yeast strains and observed that the gas1Δ strain exhibited a decreased proliferation ability and a shorter replicative lifespan (RLS), as well as enhanced activity of the unfolded protein response (UPR) in the absence of stress. However, under the high-tunicamycin-concentration (an ER stress-inducing agent; 1.0 µg/mL) stress, the gas1Δ yeast cells exhibited an increased proliferation ability compared with the wild-type yeast strain. In addition, our findings demonstrated that IRE1 and HAC1 (two upstream modulators of the UPR) are required for the survival of gas1Δ yeast cells under the tunicamycin stress. On the other hand, we provided evidence that the GAS1 overexpression caused an obvious sensitivity to the low-tunicamycin-concentration (0.25 µg/mL). Collectively, our results indicate that Gas1p plays an important role in the ageing and ER stress responses in yeast.

Postnatal nectin-3 knockdown induces structural abnormalities of hippocampal principal neurons and memory deficits in adult mice.

The early postnatal stage is a critical period of hippocampal neurodevelopment and also a period of high vulnerability to adverse life experiences. Recent evidence suggests that nectin-3, a cell adhesion molecule, mediates memory dysfunction and dendritic alterations in the adult hippocampus induced by postnatal stress. But it is unknown whether postnatal nectin-3 reduction alone is sufficient to alter hippocampal structure and function in adulthood. Here, we down regulated hippocampal expression of nectin-3 and its heterophilic adhesion partner nectin-1, respectively, from early postnatal stage by injecting adeno-associated virus (AAV) into the cerebral lateral ventricles of neonatal mice (postnatal day 2). We found that suppression of nectin-3, but not nectin-1, expression from the early postnatal stage impaired hippocampus-dependent novel object recognition and spatial object recognition in adult mice. Moreover, AAV-mediated nectin-3 knockdown significantly reduced dendritic complexity and spine density of pyramidal neurons throughout the hippocampus, whereas nectin-1 knockdown only induced the loss of stubby spines in CA3. Our data provide direct evidence that nectins, especially nectin-3, are necessary for postnatal hippocampal development of memory functions and structural integrity.

Effects of Polymorphisms in NR1H4, NR1I2, SLCO1B1, and ABCG2 on the Pharmacokinetics of Rosuvastatin in Healthy Chinese Volunteers.

The nuclear receptors (NR)-farnesoid X receptor (FXR, NR1H4) and pregnane X receptor (PXR, NR1I2)-have important effects on the expression of genes related to the pharmacokinetics (PKs) of rosuvastatin. This study was designed to investigate whether the genetic variants in drug disposition genes (SLCO1B1 and ABCG2) combined with their upstream regulators (NR1H4 and NR1I2) would affect the PKs of rosuvastatin in a Chinese population. Sixty-one healthy male volunteers were enrolled and the plasma concentrations of rosuvastatin were measured using the liquid chromatographic-tandem mass spectrometry/MS method. All subjects were analyzed and grouped according to the genotypes of NR1H4, NR1I2, SLCO1B1, and ABCG2. The exposure of rosuvastatin was higher in subjects carrying the SLCO1B1 521C or ABCG2 421A allele compared with noncarriers. No association was observed of single-nucleotide polymorphisms in NR1H4 or NR1I2 genes with the PKs of rosuvastatin. After adjusting for the 421C>A and 521T>C variants, the Cmax in subjects with NR1I2 63396TT wild type were about 2-fold of those of NR1I2 mutant type (63396CC and CT) (10.7 vs. 20.4 ng/mL, P = 0.023), whereas no significant differences were observed for other parameters. Polymorphisms investigated in the genes of NR1H4 and NR1I2 seemed to play no significant role in the disposition of rosuvastatin.

Influence of ABCB1, CYP3A4*18B and CYP3A5*3 polymorphisms on cyclosporine A pharmacokinetics in bone marrow transplant recipients.

The aim of this study was to retrospectively evaluate the effect of polymorphisms in the CYP3A4, CYP3A5 and ABCB1 genes on the dose-adjusted concentration and dose requirement of cyclosporine A(CsA) in Chinese recipients during the early period after bone marrow or hematopoietic stem cell transplantation. Ninety-one bone marrow transplant recipients were genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay or by direct sequencing for the C1236T, G2677T/A and C3435T polymorphisms in CYP3A4*18B, CYP3A5*3, and ABCB1, respectively. The concentration at zero before administration (C0) and concentration at 2 h after administration (C2) of whole blood CsA were measured by fluorescence polarization immunoassay. Dose-adjusted C0 and C2 were determined and compared among groups with different genotypes. Compared with CYP3A5*3/*3 individuals, CYP3A5*1/*1 subjects have a significantly lower dose-adjusted C0 and C2 at days 1-10 and a higher dose requirement for CsA at days 16-30 (p < 0.05). In addition, homozygotes for the ABCB1 3435T mutant have a significantly higher dose-adjusted C0 and C2 and a lower dose requirement compared with wildtype (p < 0.05). Similar results were also derived for carriers of the T-G-C haplotype in CYP3A5 producers compared with non-carriers (p < 0.05 and p < 0.01, respectively). In summary, the ABCB1 3435T SNP, T-G-C haplotype in CYP3A5 producers, and CYP3A5*3 SNP are all associated with differences in CsA pharmacokinetics and dose requirements during the first month after bone marrow or hematopoietic stem cell transplantation. Genetic testing can therefore help to determine initial dosage and individualize immunosuppressive therapy.

[Relationship between expression of cyclin D1, Ki-67 and bcl-2 and biologic behavior in CD117-positive gastrointestinal stromal tumors].

OBJECTIVE: To investigate the clinicopathologic features of gastrointestinal stromal tumors (GISTs) and to identify reliable prognostic parameters. METHODS: Fifty-nine GISTs were studied by immunostaining of CD117, CD34, SMA, desmin, S-100, bcl-2, and Ki-67. Histopathologic evaluations included tumor size, necrosis, histological growth patterns, mitotic activities and tumor lymphocytic infiltrate. The patients were clinically followed for 2 to 9 years. Univariate, multivariate and correlative statistical evaluations were used to analyze the data. RESULTS: Among the 59 patients, 40 were alive and 15 died of their tumors at follow-up, the remaining 4 patients died of other causes. Pathological parameters that correlated with prognosis included tumor sizes of more than 5 cm, tumor tissue necrosis, mitotic cell count equal or higher than 5 per 50 high power field, Ki-67 labeling index (LI) equal or higher than 5% and intense bcl-2 immunostaining. Multivariate analysis showed that the mitotic count and Ki-67 LI were independent prognostic indicators. There was a correlation between mitotic count and Ki-67 LI. CONCLUSIONS: Mitotic count and Ki-67 LI are the best predictors for a poor outcome of GIST after surgical treatment. Ki-67 immunostaining may substitute mitotic count as a useful prognostic parameter.