Improved cytotoxicity and multidrug resistance reversal of chitosan based polymeric micelles encapsulating oxaliplatin.

To overcome the side effects and drug resistance in cancer chemotherapy, oxaliplatin (OXA) was encapsulated in chitosan based polymeric micelles with glycolipid-like structure, which were formed by stearic acid-grafted chitosan oligosaccharide (CSO-SA). CSO-SA with 6.89% amino substituted degree was synthesized in this paper. The critical micelle concentration was about 0.12 mg/mL. CSO-SA micelles with the concentration of 1.0 mg/mL had 34.8 nm number average diameter and +50.8 mV surface potential in the aqueous medium. Thin-film dispersed method mediated by lecithin was chosen to prepare OXA-loaded CSO-SA micelles (CSO-SA/OXA), encapsulation efficiency of which could reach up to about 47%. In vitro anti-tumor activity of CSO-SA/OXA micelles against drug sensitive tumor cells and drug resistant cells was then examined. Using SGC-7901, SKOV3, BEL-7402, K562, and MCF-7 as model drug sensitive tumor cells, the 50% inhibition of cellular growth (IC(50)) of CSO-SA/OXA micelles could be lowered about 3-6 folds compared to that of free OXA solution. Furthermore, cytotoxicity test of CSO-SA/OXA micelles against MCF-7 and multidrug resistant MCF-7 (MCF-7/Adr) cells presented the reversal activity against MCF-7/Adr cells. The present micelles are a promising carrier candidate for platinum drug to improve the anti-tumor activity.

Beta-aescin: a potent natural inhibitor of proliferation and inducer of apoptosis in human chronic myeloid leukemia K562 cells in vitro.

Beta-aescin, a natural triterpenoid saponin isolated from the seed of Chinese horse chestnut (Aesculus chinensis), is known to generate a wide variety of biochemical and pharmacological effects. In the present study, the authors investigated the anti-proliferative and apoptotic effects of beta-aescin in human chronic myeloid leukemia K562 cell line in vitro. The anti-proliferative effects were detected by CFU-K562 colony formation and cell viability assay. The apoptotic effects were analysed by morphological analysis, annexin V assay, DNA fragmentation assay and flow cytometry DNA content analysis. The results showed that beta-aescin exhibited potent dose- and time-dependent anti-proliferative effects in K562 cells. Morphological evidence of apoptosis, a significant increase of annexin V+ and PI- cells (early apoptotic) and apoptotic DNA fragmentation, were observed in cells treated with beta-aescin. Flow cytometry analysis revealed that beta-aescin could lead to an accumulation of sub G1 population in K562 cells, and suggesting a potential G1 phase accumulation in cell cycle profile of K562 cells. Our findings revealed that beta-aescin is a potent natural inhibitor of proliferation and inducer of apoptosis in K562 cells, and beta-aescin may be a candidate lead compound to explore potential antileukemia drugs.

Purification and characterization of antitoxic proteins from the serum of Agkistrodon halys Pallas.

In this study, the authors report the purification and characterization of antitoxic proteins from the serum of Agkistrodon halys Pallas. Two antitoxic proteins have been successfully isolated by the methods of (NH4)(2)SO(4) fractional precipitation, chromatography and preparative discontinuous polyacrylamide gel electrophoresis (PAGE). We have measured their molecular weights by Sephadex G-150 chromatography and 0.1% SDS-Tris-HCl discontinue PAGE respectively. Antitoxin I was about 138,000+/-40 Da and antitoxin II was about 76,000+/-40 Da, they are all single-chain peptides. We have measured their capacity to neutralize the toxicity of agkistrodotoxin (ATX), and their capacity to inhibit the PLA(2) activity of ATX. The results showed that antitoxin I could increase LD(50) of ATX from 0.25+/-0.05 to 0.445+/-0.13 mg/kg, decrease its PLA(2) activity from 2.36 to 1.72 microm/mg min, and antitoxin II could increase LD(50) of ATX from 0.25+/-0.05 to 0.56+/-0.12 mg/kg, decrease Phospholipase A(2) (PLA(2)) activity from 2.36 to 1.2 microm/mg min. When the natural antitoxins were mixed with different amounts of ATX and inoculated intraperitonially into eight mice, it was found that 0.5 mg antitoxin I could neutralize the toxicity of 0.4 mg ATX and 0.5 mg antitoxin II could neutralize the toxicity of 0.5 mg ATX completely. These antitoxic proteins could neutralize the toxicity of ATX completely and inhibit ATX's PLA(2) activity partially.

[Effect of panaxadiol saponin and panaxtrol saponin on proliferation of human bone marrow hemopoietic progenitor cells].

OBJECTIVE: To observe the effect of panaxadiol saponin (PDS) and panaxtrol saponin (PTS) on proliferation of human bone marrow hemopoietic progenitor cells (HPC). METHODS: PDS and PTS were separated and purified from ginsenosides, and the effects on HPC were studied using in vitro hemopoietic progenitor cell colony-forming technique, by observing the proliferation of human burst forming unit-erythroid progenitor (BFU-E), colony-forming unit-erythroid (CFU-E), colony-forming unit-granulocyte/macrophage (CFU-GM) and colony-forming unit-pluripotent hemopoietic progenitor (CFU-Mix) in mice after PDS and PTS stimulation. RESULTS: Different concentration of PDS (2.5-200 micrograms/ml) could stimulate the proliferation of HPC obviously, showing increase of CFU-E, BFU-E, CFU-GM and CFU-Mix by 54.9 +/- 6.3%, 48.8 +/- 5.1%, 27.6 +/- 4.2% and 48.9 +/- 3.9% respectively, which was higher than that of the control group. While stimulated by PTS of the same concentration, the CFU-E and BFU-E was lower than that of control significantly (P < 0.05); when the terminal concentration of PTS was 200 micrograms/ml, CFU-E and BFU-E was zero respectively. In the CFU-GM culture, PTS in concentration of 12.5 micrograms/ml could cause the proliferation increased by 29.7 +/- 2.2% (P < 0.05), but in concentration of 100 micrograms/ml and 200 micrograms/ml, it showed inhibitory effect on CFU-GM, the inhibition rate being 48.6 +/- 3.9% and 100% respectively. CONCLUSION: PDS is the effective component of ginsenosides in stimulating proliferation of human bone marrow HPC. PTS is an component with inhibitory action on proliferation of CFU-E and BFU-E and its effect on CFU-GM was depending on its concentration.

[Effect of Panax notoginsenosides on the proliferation of hematopoietic progenitor cells in mice with immune-mediated aplastic anemia].

OBJECTIVE: To study the effect of panax notoginsenosides (PNS) on the proliferation of hematopoietic progenitor cells (HPC) in mice with immune-mediated aplastic anemia. METHODS: Balb/c mice model of immune-mediated aplastic anemia was established by radiation with sublethal dose of 60Co following the intravenously infusing lymphocytes of DBA/2 mice. Model mice in the treated groups were treated separately with high, middle and low dose of PNS, 3.2 mg, 1.6 mg and 0.8 mg per day respectively by intraperitoneal injection. Model mice in the control group and normal mice in the normal control group were treated with normal saline. The peripheral white blood cell (WBC) count and pathological examination of bone marrow were carried out 12 days later, the bone marrow was taken to be incubated in semi-solid culture system for observing proliferation of HPC. RESULTS: PNS could (1) increase peripheral WBC count: as compared with that in the model control, WBC in the high, middle and low dose PNS groups was raised by (34.3 +/- 2.9)%, (29.2 +/- 1.7)% and (14.5 +/- 1.6)% respectively, P < 0.01 and P < 0.05; (2) improve the bone marrow inhibition: pathological examination showed in the model group, the hematopoietic structure was destroyed and replaced by fatty tissue, while in the PNS treated groups, the structure of marrow was rather complete and filled with abundant hematopoietic cells; (3) promote the proliferation of HPC: as compared with the model group, the colony formation of CFU-GM were increased by (64.4 +/- 2.8)%, (67.3 +/- 2.4)% and (21.9 +/- 1.8)% respectively and that of CFU-E increased by (31.9 +/- 3.6)%, (20.7 +/- 2.4)% and (12.8 +/- 2.6)% respectively in the three PNS treated group (P < 0.01 and P < 0.05). CONCLUSION: PNS could enhance hematopoiesis by promoting proliferation of CFU-GM and CFU-E progenitors so as to improve the hematopoietic function in mice of immune-mediated aplastic anemia.

[Study on induction of ginsenosides on HL-60 cell apoptosis].

OBJECTIVE: To observe whether the Ginsenosides (GS) could induce HL-60 cell line apoptosis from promyelocytic leukemia. METHODS: HL-60 cells were treated with GS of various concentration to observe the effect of GS on cell morphological change, the DNA content change by flow cytometry, DNA ladder by electrophoresis, and apoptosis rate by Annexin V-FITC test of the cells. RESULTS: GS could inhibit the growth of HL-60 cells and induce cell apoptosis in a certain scope of dose and reacting time. CONCLUSION: GS could specifically induce apoptosis in HL-60 cells, which provides an experimental basis for treatment of leukemia with GS as an supplemntary agent of chemotherapy.

[Effects of Ginsenosides Rg1 and Rb1 on Proliferation of Human Marrow Granulocyte-Macrophage Progenitor Cells]

Ginseng is a traditional Chinese medicine which has been used in treating anemia for thousands of years. It is composed of a lot of components. The main component is total saponin of panax ginseng (TSPG), which contains more than 20 ginsenosides including Rg1, Rb1 and so on. Previous studies have reported that total saponin of panax ginseng could promote hematopoiesis by stimulating proliferation of human erythroid grogenitor cells CFU-E and BFU-E, however, it had different effects on CFU-GM reported by various laboratories. In this study, CFU-GM assay was adopted to observe the ginsenosides Rg1 and Rb1's effects on the proliferation of human marrow grannulocyte-macrophage progenitor cells. The results showed that Rg1 and Rb1 had obvious promotive effect on the proliferation of CFU-GM, and the increasing rates of colony formation were up to (70.6 +/- 6.8)% and (65.1 +/- 6.3)%, respectively. There was no inhibiting effect on CFU-GM in high concentrations of Rg1 and Rb1. It is suggested that Rg1 and Rb1 can stimulate the proliferation of human granulocyte-macrophage progentors. The results of TSPG's various effects on CFU-GM might be caused by different contents of ginsenosides in TSPG used in different laboratories.