Research progress on the source, production, and anti-cancer mechanisms of paclitaxel / 中国天然药物

Paclitaxel, a tetracyclic diterpenoid compounds, was firstly isolated from the bark of the Pacific yew trees. Currently, as a low toxicity, high efficiency, and broad-spectrum natural anti-cancer drug, paclitaxel has been widely used against ovarian cancer, breast cancer, uterine cancer, and other cancers. As the matter of fact, natural paclitaxel from Taxus species has been proved to be environmentally unsustainable and economically unfeasible. For this reason, researchers from all over the world are devoted to searching for new ways of obtaining paclitaxel. At present, other methods, including artificial cultivation of Taxus plants, microbial fermentation, chemical synthesis, tissue and cell culture have been sought and developed subsequently. Meanwhile, the biosynthesis of paclitaxel is also an extremely attractive method. Unlike other anti-cancer drugs, paclitaxel has its unique anti-cancer mechanisms. Here, the source, production, and anti-cancer mechanisms of paclitaxel were summarized and reviewed, which can provide theoretical basis and reference for further research on the production, anti-cancer mechanisms and utilization of paclitaxel.

Protective effect of succinic acid on cerebellar Purkinje cells of neonatal rats with convulsion / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the protective effect of succinic acid (SA) on the cerebellar Purkinje cells (PCs) of neonatal rats with convulsion.</p><p><b>METHODS</b>A total of 120 healthy neonatal Sprague-Dawley rats aged 7 days were randomly divided into a neonatal period group and a developmental period group. Each of the two groups were further divided into 6 sub-groups: normal control, convulsion model, low-dose phenobarbital (PB) (30 mg/kg), high-dose PB (120 mg/kg), low-dose SA (30 mg/kg), and high-dose SA (120 mg/kg). Intraperitoneal injection of pentylenetetrazole was performed to establish the convulsion model. The normal control group was treated with normal saline instead. The rats in the neonatal group were sacrificed at 30 minutes after the injection of PB, SA, or normal saline, and the cerebellum was obtained. Those in the developmental group were sacrificed 30 days after the injection of PB, SA, or normal saline, and the cerebellum was obtained. Whole cell patch clamp technique was used to record the action potential (AP) of PCs in the cerebellar slices of neonatal rats; the parallel fibers (PF) were stimulated at a low frequency to induce excitatory postsynaptic current (EPSC). The effect of SA on long-term depression (LTD) of PCs was observed.</p><p><b>RESULTS</b>Compared with the normal control groups, the neonatal and developmental rats with convulsion had a significantly higher AP frequency of PCs (P<0.05), and the developmental rats with convulsion had a significantly decreased threshold stimulus (P<0.01) and a significantly greater inhibition of the amplitude of EPSC in PCs (P<0.05). Compared with the normal control groups, the neonatal and developmental rats with convulsion in the high-dose PB groups had a significantly decreased threshold stimulus (P<0.01), a significantly higher AP frequency of PCs (P<0.05), and a significantly greater inhibition of EPSC in PCs (P<0.05). Compared with the neonatal and developmental rats in the convulsion model groups, those in the high-dose SA groups had a significantly decreased AP frequency of PCs (P<0.05). The developmental rats in the low- and high-dose SA groups had a significantly higher AP threshold than those in the convulsion model group (P<0.05).</p><p><b>CONCLUSIONS</b>The high excitability of PCs and the abnormal PF-PC synaptic plasticity caused by convulsion in neonatal rats may last to the developmental period, which can be aggravated by PB, while SA can reduce the excitability of PCs in neonatal rats with convulsion and repair the short- and long-term abnormalities of LTD of PCs caused by convulsion.</p>

Effect of Flos Daturae Alkaloids on TGF-beta1-induced Epithelial-Mesenchymal Transition of Human Pulmonary Adenocarcinoma A549 Cells / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the effect of Flos Daturae alkaloids (FDA) on TGF-beta1-1uuuu;U epithelial-mesenchymal transition (EMT) of human pulmonary adenocarcinoma A549 cells.</p><p><b>METHODS</b>A549 cells in vitro cultured were randomly divided into 5 groups, i.e., the blank control group, the TGF-beta1 group, the low dose FDA group, the medium dose FDA group, and the high dose FDA group. The morphologies of A549 cells were observed. Expressions of cytokeratin (CK)-19 and alpha-smooth muscle actin (alpha-SMA) were detected by Western blot and real-time PCR at 24, 48, and 72 h, respectively.</p><p><b>RESULTS</b>A549 cells in the TGF-beta1, group turned from cobblestone to spindle shape gradually. Those in low, medium and high dose FDA groups showed similar shapes to those of the TGF-beta1 group. There was no statistical difference in the morphology of A549 cells among the 3 dose FDA groups (P > 0.05). Western blot showed that, when compared with the blank control group, the expression of CK-19 was down-regulated, but the expression of alpha-SMA was up-regulated in the TGF-beta1 group (P < 0.01). Compared with the TGF-beta1, group, the expression of CK-19 was up-regulated, but the expression of alpha-SMA was suppressed in low, medium and high dose FDA groups (P < 0.01). The CK-19 expression obviously increased, but the alpha-SMA expression was suppressed in high dose FDA group at 72 h (P < 0.01). Real-time PCR results showed, as compared with the TGF-beta1 group, the mRNA expression of CK-19 was increased, but the mRNA expression of alpha-SMA was reduced in low, medium and high dose FDA groups (P < 0.01).</p><p><b>CONCLUSIONS</b>FDA had no effect on EMT morphological changes of TGF-beta1 induced A549 cells. FDA could reverse characteristic markers of A549 cells during EMT to some extent, such as expressions of CK-19 and alpha-SMA. The expression of CK-19 (as the epithelium marker) increased and the expression of alpha-SMA (as the mesenchymal marker) was reduced. Besides, they were most obviously seen in the high dose FDA group at 72 h in a dose- and time-dependent manner.</p>