Two cardenolide glycosides from the seed fairs of Asclepias curassavica and their cytotoxic activities.

Two cardenolide glycosides, corotoxigenin 3-O-[ß-D-glucopyranosyl-(1→4)-6-deoxy-ß-D-glucopyranoside] (1) and coroglaucigenin 3-O-[ß-D-glucopyranosyl-(1→4)-6-deoxy-ß-D-glucopyranoside] (2), were isolated from the seed fairs of Asclepias curassavica. The structures of 1-2 were determined based on the combination of the analysis of their MS, NMR spectroscopic data and acid hydrolysis. The inhibitory effects of compounds 1 and 2 on human colorectal carcinoma cells (HCT116), non-small cell lung carcinoma cells (A549) and hepatic cancer cells (SMMC-7721) were evaluated. The results showed that both compounds 1 and 2 significantly inhibited the viability, proliferation, and migration of A549, HCT116 and SMMC-7721 cells, suggesting that compounds 1 and 2 can be applied in the treatment of lung, colon and liver cancers in clinical practice. This study may not only provide a scientific basis for clarifying the active ingredients in A. curassavica, but also help to understand its antitumor activity, which can promote the application of A. curassavica in clinical treatment of various cancers.

Genome-wide identification of abscisic acid (ABA) receptor pyrabactin resistance 1-like protein (PYL) family members and expression analysis of PYL genes in response to different concentrations of ABA stress in Glycyrrhiza uralensis.

As abscisic acid (ABA) receptor, the pyrabactin resistance 1-like (PYR/PYL) protein (named PYL for simplicity) plays an important part to unveil the signal transduction of ABA and its regulatory mechanisms. Glycyrrhiza uralensis, a drought-tolerant medicinal plant, is a good model for the mechanism analysis of ABA response and active compound biosynthesis. However, knowledge about PYL family in G. uralensis remains largely unknown. Here, 10 PYLs were identified in G. uralensis genome. Characterization analysis indicated that PYLs in G. uralensis (GuPYLs) are relatively conserved. Phylogenetic analysis showed that GuPYL1-3 belongs to subfamily I, GuPYL4-6 and GuPYL10 belong to subfamily II and GuPYL7-9 belongs to subfamily III. In addition, transcriptome data presented various expression levels of GuPYLs under different exogenous ABA stresses. The expression pattern of GuPYLs was verified by Quantitative real-time polymerase chain reaction (qRT-PCR). The study proved that GuPYL4, GuPYL5, GuPYL8 and GuPYL9 genes are significantly up-regulated by ABA stress and the response process is dynamic. This study paves the way for elucidating the regulation mechanism of ABA signal to secondary metabolites and improving the cultivation and quality of G. uralensis using agricultural strategies.

Gene losses and partial deletion of small single-copy regions of the chloroplast genomes of two hemiparasitic Taxillus species.

Numerous variations are known to occur in the chloroplast genomes of parasitic plants. We determined the complete chloroplast genome sequences of two hemiparasitic species, Taxillus chinensis and T. sutchuenensis, using Illumina and PacBio sequencing technologies. These species are the first members of the family Loranthaceae to be sequenced. The complete chloroplast genomes of T. chinensis and T. sutchuenensis comprise circular 121,363 and 122,562 bp-long molecules with quadripartite structures, respectively. Compared with the chloroplast genomes of Nicotiana tabacum and Osyris alba, all ndh genes as well as three ribosomal protein genes, seven tRNA genes, four ycf genes, and the infA gene of these two species have been lost. The results of the maximum likelihood and neighbor-joining phylogenetic trees strongly support the theory that Loranthaceae and Viscaceae are monophyletic clades. This research reveals the effect of a parasitic lifestyle on the chloroplast structure and genome content of T. chinensis and T. sutchuenensis, and enhances our understanding of the discrepancies in terms of assembly results between Illumina and PacBio.

Controllable band structure and topological phase transition in two-dimensional hydrogenated arsenene.

Discovery of two-dimensional (2D) topological insulator such as group-V films initiates challenges in exploring exotic quantum states in low dimensions. Here, we perform first-principles calculations to study the geometric and electronic properties in 2D arsenene monolayer with hydrogenation (HAsH). We predict a new σ-type Dirac cone related to the px,y orbitals of As atoms in HAsH, dependent on in-plane tensile strain. Noticeably, the spin-orbit coupling (SOC) opens a quantum spin Hall (QSH) gap of 193 meV at the Dirac cone. A single pair of topologically protected helical edge states is established for the edges, and its QSH phase is confirmed with topological invariant Z2 = 1. We also propose a 2D quantum well (QW) encapsulating HAsH with the h-BN sheet on each side, which harbors a nontrivial QSH state with the Dirac cone lying within the band gap of cladding BN substrate. These findings provide a promising innovative platform for QSH device design and fabrication operating at room temperature.

[The Antitumor Effects of Fisetin on Ovarian Cancer in vitro and in vivo.]

OBJECTIVES: We attempted to survey the inhibit effect of fisetin with human ovarian cancer cell line SKOV3 and the xenograft and the mechanism of the effect. METHODS: The ovarian cancer cell line SKOV3 treated by fisetin were observed directly under the transmission electronmicroscope (TEM);MTT assay was used to determine cell viability.Flow cytometry was used to analyze the apoptosis in ovarian cancer cell line SKOV3.In addition,we established an ovarian cancer athymicnude rat model.We observed the neoplasia and progression after fisetin treatment.The proliferation and apoptosis of athymic nude rat model were evaluated by testing Bcl-2,Bax and poly-ADP-ribose polyerase (PARP) expression through Western blot. RESULTS: The chromatin were brought together and the apoptotic bodies were detected in SKOV3 cells under transmission electron microscope after the treatment by fisetin.MTT assay indicated that fisetin inhibited ovarian cancer cell proliferation in a dose-dependent manner.The flow cytometry data demonstrated that the apoptosis might induct in SKOV3 cells after treatment by fisetin.In athymic rude rat model,under the influence of fisetin,tumor volume and tumor mass were significantly decreased.Western blot demonstrated that treatment with higher concentration of fisetin resulted in a significant decrease of Bcl-2 and a significant increase of Bax.The apoptosis proteins PARP was cut apparently. CONCLUSIONS: The results provided the first insight into antitumor anti-proliferative and the induction of apoptosis efficacy of fisetin against ovarian cancer in vitro and in vivo.All data suggested a safe promising therapeutic potential of fisetin in ovarian cancer treatment.

miR-126 Suppresses the proliferation of cervical cancer cells and alters cell sensitivity to the chemotherapeutic drug bleomycin.

In cervical cancer, one of the most common malignant tumors in women worldwide, miR-126 has been reported to exhibit decreased expression. However, its role in cervical cancer cell proliferation and drug sensitivity has remained relatively unexplored. Here, we compared the expression of miR-126 in cervical cancer tissues (n = 20) with that in normal cervical tissue (n = 20) using quantitative RT-PCR. The viability of Siha cervical cancer cells was further measured by MTT assay after transfection with miR-126 mimic (Siha-miR-126 mimic) or microRNA mimic negative control (Siha-miR mimic NC) and after treatment with various concentrations of bleomycin (BLM). IC50s were calculated, and the survival rates (SRs) of Siha cells were calculated. miR-126 expression in cervical cancer tissue was significantly decreased compared with that in normal cervical tissue (P < 0.01). The relative SRs of Siha-miR-126 mimic cells were also significantly decreased compared with those of Siha-miR mimic NC cells at 24-96 h after transfection. The IC50 of BLM in Siha-miR-126 mimic cells (50.3 ± 2.02 µg/mL) was decreased compared with that in Siha-miR mimic NC cells (70.5 ± 4.33 µg/mL) at 48 h after transfection (P < 0.05). Finally, the SRs of Siha-miR-126 mimic cells were significantly lower than those of Siha- miR mimic NC cells after cultured in medium containing 40 µg/mL BLM for 24-96 h (P < 0.05). These results suggest that miR-126 is expressed at low levels in cervical cancer. Upregulation of miR-126 inhibited cervical cancer cell proliferation and enhanced the sensitivity to BLM. Thus, miR-126 may represent a novel approach to cervical cancer treatment.

[Expression of long non-coding RNA HOTAIR mRNA in ovarian cancer].

OBJECTIVE: To investigate the long non-coding RNA HOTAIR (long non-coding HOX antisense intergenic RNA) by examining HOTAIR expression levels in ovarian cancer tissue and normal ovarian tissue. METHODS: The mRNA of long non-coding RNA HOTAIR expressions were detected by real-time fluorescence quantitative PCR in ovarian cancer (44) and normal ovary tissues (14). RESULTS: The expression of HOTAIR in ovarian cancer tissue was higher than that in normal ovarian tissue (1.26 +/- 0.27 vs. 0.14 +/- 0.09, P < 0.05). The expression was statistically higher in poorly differentiated ovarian cancer than poorly-moderately, moderately-well, and well-differentiated ones (1.65 +/- 0.41 vs. 0.39 +/- 0.14, P < 0.05). CONCLUSION: RNA HOTAIR expressions were higher in ovarian cancer; it may play a role in ovarian cancer, and become a biomarker for malignant degree of ovarian cancer and may provide a novel therapeutic target for ovarian cancer.

[Observation on anticancer function of PS II isolated from Rhizoma Paridis].

OBJECTIVE: To isolate compound Paris saponin II (PS II) from Rhizoma Paridis and observe its antitumor activity. METHODS: PS II was isolated and determined by electrospray ionization-mass spectrometry, 1H and 13C nuclear magnetic resonance spectral analysis. PS II was used to treat cancer cells to analyze the toxicity and relative time-and dose-dependent manner. Apoptosis of cells were investigated by flow cytometry and TUNEL assay. Western blotting was used to analyze the effects of PS II to MAPKs and mitochondrial apoptotic pathway. RESULTS: The anti-tumor activities of PS II on ovarian carcinoma cell line SKOV3 were investigated. The IC50 of PS II to SKOV3 was 4.81 micromol/L. Increased apoptosis rate in a dose- and time-dependent manner was observed by Flow cytometry and TUNEL. The activity of ERK1/2 was inhibited by PS II and increased expression of cytochrone c, caspase-3 and caspase-9 was also noticed after the treatment of PS II . CONCLUSION: PS II can inhibit the growth of ovarian cancer cells SKOV3 through affecting the key proteins on MAPKs pathway and inhibiting the activity of ERK1/2 and eventually eliciting programmed cell death of SKOV3. The mitochondrial apoptotic pathway may be involved in the PSII induced apoptosis.

[Establishment of a cisplatin-resistant human cervical cancer cell line].

OBJECTIVE: To establish a cisplatin (cDDP)-resistant human cervical cancer cell line named SiHa/cDDP and researched its biological characteristics. METHODS: The development of cDDP resistance in SiHa cell line was induced by continuously stepwise exposure of the cells to cDDP. Cell growth curve, doubling time and resistance index (RI) were evaluated by MTT analysis. The expression of P-gp, GST-pi, Topo I were assessed with immunocytochemical method. RESULTS: SiHa/cDDP cell line was successfully established which had stable growth, subculture, frozen reservation and resuscitation in the concentration of 2 microg/ml cDDP, doubling time was (45.82 +/- 3.69) h and RI to cDDP was 16.131. It also showed different degrees of cross-resistance to several anticancer drugs. As compared to parental SiHa, SiHa/cDDP had over-expression in P-gp and GST-pi (P < 0.01), but Topo I showed no statistically significant differences. CONCLUSION: We successfully established the cDDP-resistant human cervical cancer cell line SiHa/cDDP, which may provide ideal experimental model for research of human cervical carcinoma.

[Isolation and biological characterization of human amniotic fluid-derived stem cells].

OBJECTIVE: To establish in vitro culture procedure for human amniotic fluid-derived CD117 positive stem cells, and to identify the characteristics of CD117 positive stem cells. METHODS: 86 amniotic fluid samples (10 mL of each) were obtained by second-trimester amniocentesis. Isolation of amniotic fluid-derived stem cells expressing CD117 antigen was performed via magnetic cell sorting using the CD117 MicroBead Kit. The karyotype of CD117 positive stem cells was analysed through repeated freezing. Adipogenic differentiation of these CD117 positive stem cells was displayed by Oil Red O staining. Osteogeneic differentiation of these CD117 positive stem cells was confirmed by Alizarin Red staining. RESULTS: The CD117 positive stem cells were successfully isolated and cultured from 61 samples, with all showing normal karyotype. Product analysis of specific staining confirmed that under specific culture mediums, these cells could be successfully induced to differentiate into adipocytes and osteocytes. CONCLUSION: Based on this study, we estimate that isolating CD117 positive stem cells from second-trimester amniotic fluid obtained by amniocentesis has a success rate of 70.93%. These cells maintain morphological and genetic stability in vitro. Human amniotic fluid-derived CD117 positive stem cells have the ability to differentiate in vitro into adipocytes and osteocytes under specific culture mediums and may be applied in cell transplantation and regenerative medicine.

[Dynamic detection of regulatory T cells in murine mammary carcinoma model and its significance].

OBJECTIVE: To analyze the dynamic change of regulatory T cells in experimental murine mammary carcinoma model, and to investigate their effect on tumor progress. METHODS: Mouse mammary carcinoma models were established. The percentages of CD4+ CD25+ and CD4+ FOXP3+ regulatory T cells in the CD4+ T cells in tumor tissue, tumor draining lymph node and spleen were measured by FACS at 3 different time points after tumor challenge. The expression of CD25+ FOXP3 in CD4+ T cells was analyzed, and the expression of CD4+ T cells in T cells (CD3+) of tumor tissue. RESULTS: Compared with the normal control group, In mouse mammary carcinoma models, The percentages of CD4+ T cells to lymphocytes in lymph node and spleen were decreased in the late stage (P<0.05). The percentages of CD4+ CD25+ and CD4+ FOXP3+ regulatory T cells in the CD4+ T cells were markedly increased (P<0.05), The percentages of CD25+ FOXP3+ regulatory T cells in the CD4+ T cells were markedly increased also (P<0.05). In the tumor tissue, the percentages of CD4+ T cells and CD4+ CD25+ regulatory T cells in T cells (CD3+) were increased in three weeks after the tumor challenge than one week (P< 0. 05). The percentages of CD4+ CD25+ and CD4+ FOXP3+ regulatory T cells in the CD4+ T cells have no change between one week and three weeks after tumor planting (P>0.05). CONCLUSION: Regulatory T cells were significantly increased in malignant tumor model, and closely related to the development of tumor.

[Regional characteristics of sulfur contents in flue-cured tobacco in Hunan Province and their influence to smoking quality].

A total of 559 flue-cured tobacco samples with 3 grades (B2F, C3F and X2F) were collected from the main tobacco-growing areas in Hunan Province, and their sulfur contents were determined to study the regional characteristics of the sulfur contents and their quantitative correlations with the evaluation indices of smoking quality. The results showed that the sulfur content in the flue-cured tobacco was 0.100%-2.106% , with a mean of 0.884%. The samples with sulfur content above 0.7% accounted for 71.56% of the total. The sulfur content decreased gradually from the high sulfur content area of Central Hunan to South Hunan and Northwest Hunan. With increasing sulfur content in tobacco leaf, the aroma quality, aftertaste, combustibility and ash color went to bad, offensive odor and irritation property increased, and aroma taste, eat-taste and total smoking quality score fell down. Under the influence of applying larger amount sulfate potassium and of sulfur-type acid precipitation, the sulfur content in tobacco leaf was somewhat higher in partial areas of Hunan Province, and gave negative impact on tobacco quality, being one of key factors limiting the improvement of tobacco quality and ought to be attached enough importance in tobacco production.