Inhibitory effects and mechanisms of cryptotanshinone on the growth of tamoxifen resistant breast cancer cells / 药学学报

This study investigated the inhibitory effect and mechanisms of cryptotanshinone (CPT) on tamoxifen resistant cell MCF7-TAMR. The inhibitory effect of CPT on the viability of MCF7-TAMR cells was evaluated using the MTT assay. We found that CPT significantly inhibited the growth of MCF7-TAMR cells in a dose- and time-dependent manner. The half inhibitory concentration (IC50) is 15.14 ± 2.82 μmol·L-1 at 24 h. CPT induced cell cycle arrest of MCF7-TAMR cells at G0/G1 phase, and promoted apoptosis of MCF7-TAMR cells by upregulating intracellular levels of reactive oxygen species (ROS). Transwell results showed that CPT significantly inhibited the migration of MCF7-TAMR cells. Furthermore, CPT decreased the CD24-/lowCD44+ cell population in MCF7-TAMR cell-derived microspheres. Western blot results showed that CPT effectively inhibited the phosphorylation of estrogen receptor α (ER-α), and reduced the expression of phosphatidylinositol 3-kinase (PI3K-p85), serine-threonine protein kinase (Akt) and multidrug transporter ATP-binding cassette superfamily G member 2 (ABCG2). These results showed that CPT can induce cell apoptosis, cause cell cycle arrest, inhibit cell migration and inhibit ER-α phosphorylation, inhibit PI3K/Akt signaling pathway, reduce the number of CD24-/lowCD44+ cells and the expression of ABCG2, overcome cell drug resistance.

Research progress and analysis on mechanism of polysaccharides against type 2 diabetes mellitus / 中国中药杂志

Polysaccharides are macromolecular compounds formed by more than 10 monosaccharide molecules linked by glycosidic bonds. Polysaccharides have a wide range of sources, high safety and low toxicity, with a variety of biological activities, such as anti-tumor, anti-virus, immune regulation, lowering blood glucose, and lowering blood lipids. Type 2 diabetes mellitus(T2 DM) is a chronic metabolic disorder characterized by hyperglycemia, insulin resistance and low inflammation. In recent years, the treatment of T2 DM with polysaccharide has become a research hotspot. Polysaccharides can not only make up for the side effects such as hypoglycemia, weight gain, gastrointestinal injury caused by long-term treatment of acarbose, biguanidine and sulfonylurea, but also play an effective role in reducing glucose by regulating glucose metabolism, oxidative stress, inflammatory response, intestinal flora, etc. In this paper, the research progress of polysaccharides in the treatment of T2 DM was reviewed. In addition, the hot spots such as the hypoglycemic activity of polysaccharides with structural modifications were summarized, providing theoretical guidance for the development of active polysaccharide hypoglycemic medicines and the further study of action mechanism.

Recent research progress in immunomodulatory effects of Chinese herbal medicine on asthma treatment / 中国中药杂志

Asthma is a kind of chronic respiratory inflammation, commonly with breathlessness, chest tightness, coughing, recurrent episodes of wheezing and airflow obstruction, severely affecting human health. A variety of immunocytes are involved in this chronic disease. Chinese herbal medicine(CHM) has a long history in the treatment of asthma. A large number of studies have shown that CHM could ameliorate asthma symptoms through regulating cellular immune responses. This paper reviewed the studies of CHM on the regulation of immunocytes and their mechanisms in recent years, including the count of inflammatory cells, maturation of dendritic cells, balance of helper T cell subtypes, induction of regulatory T cells and intracellular signaling pathways. We also proposed the future research directions about the effects of CHM on asthma treatment.

Molecular and functional comparisons of the vacuolar Na+/H+ exchangers originated from glycophytic and halophytic species / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

A novel vacuolar Na+/H+ exchanger, CgNHX1, was cloned from a halophytic species Chenopodium glaucum by using reverse transcriptase-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) technique. Sequence alignment and phylogenetic analysis of 22 NHX genes from GenBank as well as the new CgNHX1 gene indicate that NHX genes shared a great degree of similarity, regardless of their glycophytic or halophytic origin. Expression of the CgNHX1 gene was induced by NaCl and peaked at 400 mmol/L NaCl. Overexpression of NHX1 genes in rice enhanced their tolerance to salt stress. However, there is no significant difference in salt tolerance among the transgenic rice plants overexpressing the NHX1 genes from either glycophytic or halophytic species. The Na+ content of both the wild type (WT) and transgenic plants increased when exposed to 50 and 100 mmol/L NaCl, and the Na+ concentration in transgenic plants was marginally higher than that of WT. Our data demonstrate that the overexpression of the NHX1 gene from either glycophytic or halophytic species resulted in the enhanced tolerance to salt stress at a similar level, suggesting that NHX gene per se might not be the reason accounting for the difference in salt tolerance between glycophytes and halophytes.

Using single primer PCR to amplify the orf25 gene fragment related to plant male-sterility in Salicornia europaea / 生物工程学报

The gene orf25 encodes functional protein that may play an important role in plant fertility control in nature. To clone the orf25 from Salicornia europaea Xinjiang into a T-vector, a single designed primer was used to amplify 1.7kb cDNA fragment with RT-PCR. Sequence analysis reveals that the cloned fragment contains entire orf25 coding region with 98%, 95%, 92% and 88% identity to that of orf25 from Beta vulgaris, Nicotiana, wheat and maize mitochondrion, respectively. This analysis suggests that orf25 gene is highly conserved in terms of evolution in plant; and it also suggests that wild plant Salicornia europaea contain a male-sterility gene similar to crops that is of great importance in improvement of the breed of crop.

Sequence analysis of bacterial transposon in NHX gene of Populus euphratica / 生物工程学报

The United Nations Environment Program estimates that approximately 20% of agricultural land and 50% of cropland in the world is salt-stressed. The gene NHX (Na+/H+ exchanger) encodes functional protein that catalyzes the countertransport of Na+ and H+ across membranes and may play an important role in plant salt tolerance. To clone the NHX from the wild plant Populus euphratica collected in Tarim basin and Xinjiang Wujiaqu district into a T-vector, designed primer was used to amplify 1kb NHX cDNA fragment with RT-PCR. Total RNA was extracted from Populus euphratica tissue (plant tissue was collected from Tarim basin and Xinjiang Wujiaqu district and stored in liquid nitrogen) according to the Plant RNA Mini Kits of Omega. First cDNAs were synthesized from 1 microg total RNA of Populus euphratica seedling. A pair of primers were used to perform RT-PCR. The amplified DNA fragment was purified and cloned into pMD18-T vector. However, 1kb and 2.3kb fragment were obtained from Tarim basin and Xinjiang Wujiaqu district and named as PtNHX and PwNHX, respectively. Sequence analysis reveals that the cloned PtNHX fragment of Populus euphratica contains partial NHX coding region with 98%, 86%, 84% and 80% identity comparing with Atriplex gemelini, Suaeda maritima, Arabidopsis thaliana and Oryza sativa, respectively. This analysis suggests that NHX gene would be highly conserved in terms of evolution in plant; and it also suggests that the NHX gene of Populus euphratica also would have the similarity with that of Arabidopsis. It may be of great importance in improvement of the plant salt tolerance and breed of crop. At the same time, sequence analysis shows that PwNHX gene includes a coding region about 1350bp with 99% identity comparing with transposon Tn10 IS10-left transposase of Shigella flexneri. On the one hand, the NHX gene may lose its function because it was inserted a fragment in coding region. On the other hand, its product may play a important role in salt tolerance. Populus grow in saline soil. It speculates that it may have other salt tolerance mechanism in Populus. The transposon can be used as transposon tagging to clone other genes and it will help us to understand farther the salt tolerance mechanism.