Targeting Hedgehog signaling pathway and autophagy overcomes drug resistance of BCR-ABL-positive chronic myeloid leukemia

The frontline tyrosine kinase inhibitor (TKI) imatinib has revolutionized the treatment of patients with chronic myeloid leukemia (CML). However, drug resistance is the major clinical challenge in the treatment of CML. The Hedgehog (Hh) signaling pathway and autophagy are both related to tumorigenesis, cancer therapy, and drug resistance. This study was conducted to explore whether the Hh pathway could regulate autophagy in CML cells and whether simultaneously regulating the Hh pathway and autophagy could induce cell death of drug-sensitive or -resistant BCR-ABL⁺ CML cells. Our results indicated that pharmacological or genetic inhibition of Hh pathway could markedly induce autophagy in BCR-ABL⁺ CML cells. Autophagic inhibitors or ATG5 and ATG7 silencing could significantly enhance CML cell death induced by Hh pathway suppression. Based on the above findings, our study demonstrated that simultaneously inhibiting the Hh pathway and autophagy could markedly reduce cell viability and induce apoptosis of imatinib-sensitive or -resistant BCR-ABL⁺ cells. Moreover, this combination had little cytotoxicity in human peripheral blood mononuclear cells (PBMCs). Furthermore, this combined strategy was related to PARP cleavage, CASP3 and CASP9 cleavage, and inhibition of the BCR-ABL oncoprotein. In conclusion, this study indicated that simultaneously inhibiting the Hh pathway and autophagy could potently kill imatinib-sensitive or -resistant BCR-ABL⁺ cells, providing a novel concept that simultaneously inhibiting the Hh pathway and autophagy might be a potent new strategy to overcome CML drug resistance.     

汉防己甲素联合顺铂对乳腺癌细胞的作用

目的:汉防己甲素和顺铂联合作用乳腺癌细胞,来提高癌细胞对顺铂的敏感性.方法:运用原子力显微镜对乳腺癌细胞表面的超微结构进行表征;MTr法和流式细胞术检测细胞的生长抑制率和细胞周期变化.结果:顺铂和汉防己甲素分别作用乳腺癌细胞48h IC50值为26.33μmoL/l和5.6μmok/l;联合用药组的IC50值为汉防己甲素2.5μmol/L和顺铂13.32μmol/l,在低浓度的联合用药作用乳腺癌细胞24h细胞膜表面结构被破坏,产生孔洞,作用48h被严重破坏使细胞周期在S比例增加为51.7%±0.30%.结论:提高了癌细胞对抗癌药物的敏感性,联合用药通过改变了细胞膜的结构对癌细胞进行有效杀伤,抑制肿瘤细胞生长.     

Search for substrate-based inhibitors fitting the S2' space of malarial aspartic protease plasmepsin II.

Plasmepsin (Plm) has been identified as an important target for the development of new antimalarial drugs, since its inhibition leads to the starvation of Plasmodium falciparum. A series of substrate-based dipeptide-type Plm II inhibitors containing the hydroxymethylcarbonyl isostere as a transition-state mimic were synthesized. The general design principle was provision of a conformationally restrained hydroxyl group (corresponding to the set residue at the P2' position in native substrates) and a bulky unit to fit the S2' pocket.     

The development of non-separation time-resolved fluoroimmunoassays for the measurement of urinary metabolites

We describe the principles of a new generation of sequential or simultaneous time-resolved fluoroimmunoassays, namely, simple, rapid, liquid-phase non-separation procedures which may be applied to the measurement of urinary steroid and drug metabolites. As an example, a method for the measurement of estrone-3-glucuronide in undiluted urine is reported. This method has a similar sensitivity, specificity and accuracy to a conventional separation fluoroimmunoassay or radioimmunoassay but in terms of speed, convenience, precision, reliability and clinical utility the new method has many advantages. The labelled antigen is a novel fluorescent europium chelate covalently linked to estrone-3-glucuronide. The antibody-binding reaction involves the incubation of the labelled antigen (2ng) with a limited concentration of polyclonal or monoclonal antibodies to estrone-3-glucuronyl-6-BSA and an aliquot of standard or sample (undiluted urine; 10 μl) in microtitre wells. After a 10 min incubation, the fluorescence which emanates from the antibody-free label is measured in a time-resolved fluorometer and is proportional to the concentration of estrone-3-glucuronide in the standard or sample. The method may be applied for the monitoring of ovarian function in women.     

Correlation between cell survival,clonogenic activity and micronuclei induction in DMBA-OC-1R cells treated with immunospecific albumin microspheres containing cisplatin and 5-fluorouracil

An ideal chemotherapeutic strategy would be to deliver a high concentration of drug that would be released in sustained small amounts from targeted microspheres to effectively kill only the tumour cells and thus reduce toxicity to normal tissue. Clonogenic and cell survival growth curve assays, as well as the micronucleus assay, were used to determine the feasibility of employing targeted immunomicrospheres in the treatment of cancer. Cells of a rodent ovarian carcinoma cell line, were exposed to cisplatin and 5-fluorouracil, either as free drug or encapsulated in albumin microspheres that were either conjugated to monoclonal antibodies or not. In cell survival growth curve assays, cell survival was reduced to 1.2% of the control when cells were treated with drug-containing immunomicrospheres. 3.2-fold more micronuclei were found in those cells that had been exposed to the drugs in immunomicrospheres than in those subjected to untargeted microspheres. All three assays demonstrated that the targeted immunomicrospheres were more effective in delivering cisplatin and 5-fluorouracil directly to the cells than the unconjugated microspheres, thus suggesting that targeted chemotherapy might be a more effective option in the treatment of cancer.     

Colloidal stability of carbon nanotubes in an aqueous dispersion of phospholipid

Within the family of nanomaterials, carbon nanotubes (CNTs) have emerged as a new efficient scaffold for studying molecular interactions at interfaces. Poor dispersability of CNTs in any solvent presents a considerable drawback for the development of novel functional composite structures. Previous studies have demonstrated that the solubility of CNTs can be greatly enhanced by employing appropriate surfactants, some of them being biological molecules. In this work, we study the noncovalent wrapping of lipid chains onto the graphitic surface of single-walled material (SWCNTs) by electron microscopy and Raman spectroscopy. Stable and homogenous aqueous suspensions of SWCNTs in the presence of lipids have been prepared, whereas their electrophoretic mobility was confirmed by zeta-potential measurements. Raman measurements revealed that smaller diameter SWCNTs are preferentially dispersed by lipid molecules in the aqueous supernatant part of the prepared suspension.     

Redescription of a poorly known marine ciliate, Leptoamphisiella vermis Gruber, 1888 n. g., n. comb. (ciliophora, stichotrichia, pseudoamphisiellidae), from the Yellow Sea, China

Leptoamphisiella vermisGruber, 1888 n. g., n. comb. (basionym Epiclintes vermisGruber, 1888) is an extraordinarily large and worm-like marine stichotrichous ciliate. Based on a population isolated recently from coastal waters of Qingdao, China, the living morphology and infraciliature are redescribed and its taxonomic position is defined. Accordingly, a new diagnosis for this species is suggested: large, marine Leptoamphisiella with a conspicuous layer of pellicular alveoli; 400-1000 microm x 40-70 microm in vivo; body band-like, highly flexible; about 40 membranelles; always three frontal and two buccal cirri; 52-80 transverse cirri (TC) extending to the posterior end of the buccal field; 57-79 left midventral and 44-62 right midventral cirri; 62-102 cirri in left and 63-91 cirri in right marginal rows (MR); 9-13 dorsal kineties that extend the full body length; about 100 macronuclear nodules and 5-13 micronuclei. The diagnosis for the new genus is as follows: vermiform Pseudoamphisiellidae with strongly contractile body, differentiated frontal, buccal, and highly developed TC; two remarkably separated midventral rows; one MR on each side of the body; frontoterminal and caudal cirri absent. Leptoamphisiella vermis n. comb. is fixed as the type species of the new genus.     

Interaction between Shaoyao–Gancao–Tang and a laxative with respect to alteration of paeoniflorin metabolism by intestinal bacteria in rats

Shaoyao-Gancao-Tang (SGT), a traditional Chinese herbal medicine (Kampo formulation) containing Shaoyao (Paeoniae Radix) and Gancao (Glycyrrhizae Radix), is co-administered with laxative sodium picosulfate as a premedication for relieving the pain accompanying colonoscopy. Paeoniflorin (PF), an active glycoside of SGT, is metabolized into the antispasmodic agent paeonimetabolin-I (PM-I) by intestinal bacteria after oral administration. The objective of the present study was to investigate whether the co-administered laxative (sodium picosulfate) influences the metabolism of PF to PM-I by intestinal bacteria. We found that the PF-metabolizing activity of intestinal bacteria in rat feces was significantly reduced to approximately 34% of initial levels by a single sodium picosulfate pretreatment and took approximately 6 days to recover. Repeated administration of SGT after the sodium picosulfate pretreatment significantly shortened the recovery period to around 2 days. Similar results were also observed for plasma PM-I concentration. Since PM-I has muscle relaxant activity, the present results suggest that repetitive administration of SGT after sodium picosulfate pretreatment might be useful to relieve the pain associated with colonoscopy.     

Effective resolution of racemic pirlindole at the preparative scale

Pirlindole, a racemic antidepressant drug, was recently resolved using the derivatization method coupled with preparative HPLC. In order to improve this technique, the use of amino acid derivatives as chiral derivatizing agents (CDA) was investigated. Among different residues, the (L)-phenylalanine methyl ester was found to be very effective to separate pirlindole enantiomers using a medium pressure liquid chromatographic (MPLC) method. This procedure is better adapted to preparative application than HPLC. Thus, several grams of the pirlindole antipodes were isolated and characterized. These two enantiomers permitted the study of the stereochemical influence at the pharmacological level. Chirality 11:261–266, 1999. © 1999 Wiley-Liss, Inc.