Active loading of verteporfin into cationic liposome for neovasculature- and tumor-targeted photodynamic therapy / 药学学报

To target neovasculature and tumor cells, a novel cationic liposome with verteporfin (BPD) active-loaded in lumen (CLL) was designed and its basic in vitro and in vivo behaviors were evaluated in this study. Calcium acetate gradient loading method was applied to encapsulate BPD actively and cationic lipid (2,3-dioleoy-loxy-propyl)-trimethylammonium (DOTAP) was added by post-insertion for the positive charge of CLL. Results of characterization showed that the diameter and zeta-potential of CLL were around 100 nm and 28 mV, respectively. Compared with passive loading liposomes, CLL significantly enhanced the stability of BPD loading. What's more, the loaded BPD in lumen could switch off the fluorescence and photosensitization during blood circulation by homo-fluorescence resonance energy transfer (homo-FRET) effect, leading to the diminished phototoxicity to normal tissues. In vitro cellular uptake and cytotoxicity assay exhibited that positive charge dramatically enhanced the uptake of CLL both in vascular endothelial cells and tumor cells leading to superior therapeutic efficacy. In vivo study further showed that CLL reduced the clearance rate and increased tumor accumulation compared with passive loading group. Quantitative results of exvivo organ indicated that negligible CLL distributed in normal organs contributing to low phototoxicity. Animal experiments were conducted according to the Guidelines of the Experimental Animal Ethics Committee of Peking University Health Science Center and International Animal Experiments. In conclusion, we successfully designed a novel cationic targeting liposome that overcame the limitations of passive loading and significantly enhanced the efficacy of photodynamic therapy.

Characteristic spectrum and decoction process of classical prescription Qingwei San / 中国中药杂志

In this experiment, by determination of the HPLC characteristic spectrum of the classical prescription Qingwei San decoction, the contents of isoferulic acid, palmatine and paeonol in Qingwei San decoction and the extraction rate were investigated. The factors such as the crushing degree of decoction pieces, the amount of decocting water, the decocting time, the filter material and the decocting container involved in Qingwei San decoction process were examined to make a detailed comparison of Qingwei San's decoction processes during the development.HPLC characteristic spectrum method of Qingwei San was established, and then the decoction process parameters of Qingwei San were optimized, with the similarity of characteristic spectrum, the concentration of the index components and the extraction rate as indexes. The decoction process of Qingwei San was determined as follows: Qingwei San decoction pieces were weighed according to the prescription amount and pulverized into the most coarse powder; the powder was put in a ceramic pot, added with 225 mL water, heated to boiling, cooked for 50 minutes with gentle heat(100 W), and filtered with a layer of 300 mesh nylon cloth.The similarity of Qingwei San's characteristics pectrum of different decoction methods was all above 0.9, and the concentration of isoferulic acid, palmatine and paeonol in Qingwei San under determined decoction process was 40.74, 26.73, 65.73 μg·mL~(-1), respectively, with an extraction rate of 33.80%.The characteristic spectrum determined in this experiment can better express the information and index components of Qingwei San, and if combined with the extraction rate information, it can provide the general information, index component content and extraction information. The decoction process after detailed investigation can better reflect the quality of Qingwei San decoction, with easier control and operation. It can provide a basis for the subsequent research and development of Qingwei San decoction standard, and can also provide experimental basis and reference for the decoction process research of other classical prescriptions.

Ca(2+)-dependent potassium channels play important roles in regulatory volume decrease in human nasopharyngeal carcinoma cells / 生理学报

It has been shown that cell volume regulation mechanisms play important roles in various cell functions. We demonstrated previously that volume-activated chloride channels were involved in cell volume regulation. The present study aimed to clarify the roles of various types of potassium channels in regulatory volume decrease (RVD) induced by hypotonic challenges in human nasopharyngeal carcinoma cells (CNE-2Z cells). The whole-cell patch clamp technique was used to record hypotonic challenge-induced potassium currents. During current recordings, cells were held at 0 mV and stepped to +/-46 and +/-92 mV, repeatedly. The cell volume was computed from cell diameters. The changes of cell volume were monitored and analyzed by the time-lapse imaging technique. The results showed that the exposure to 160 mOsm/L hypotonic solution caused the cells to swell by (144.5+/-4.2)%, activated a potassium current (59.2 pA/pF+/-13.3 pA/pF at 92 mV), and induced RVD. Cell volume was recovered from hypotonic challenge-induced swelling by (48.9+/-4.6)% after 20 min. The potassium current (at 92 mV) and RVD were inhibited by the calcium-dependent potassium channel blocker, clotrimazole (100 mumol/L), by (98.5+/-2.8)% and (89.3+/-4.9)%, respectively. Depletion of extracellular calcium prevented the activation of the hypotonic challenge-induced potassium current and inhibited the process of RVD. The voltage-gated potassium channel blocker, 4-AP (5 mmol/L), partially inhibited the hypotonic challenge-activated potassium currents by (66.6+/-5.3)% (at 92 mV). These results suggest that the Ca(2+)-dependent potassium channel is the main component of volume-activated potassium channels and plays an important role in volume regulation of CNE-2Z cells. The voltage-gated potassium channels may also contribute in part to the formation of the volume-activated potassium current.