Liposomes encapsulated iridium(III) polypyridyl complexes enhance anticancer activity in vitro and in vivo.

Three iridium(III) complexes [Ir(ppy)2(CPIP)](PF6) (Ir-1, ppy = 2-phenylpyridine, CPIP = 2-(4-chlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline), [Ir(ppy)2(DCPIP)](PF6) (Ir-2, DCPIP = 2-(3,4-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) and [Ir(ppy)2(TCPIP)](PF6) (Ir-3, TCPIP = 2,3,5-trichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) were synthesized and characterized. The complexes Ir-1, Ir-2 and Ir-3 were encapsulated in liposomes to form Ir-1-Lipo, Ir-2-Lipo and Ir-3-Lipo. Morphology, size distribution, and zeta potential of liposomes were examined by transmission electron microscopy (TEM) and Zetasizer. The cytotoxic activity in vitro of Ir-1, Ir-2 and Ir-3 against cancer A549, HTC-116, HepG2, BEL-7402, Eca-109, B16, HeLa SGC-7901 and normal NIH3T3 cells was evaluated by 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) method. Ir-2 and Ir-3 show no cytotoxic activity against the selected cancer cells, and Ir-1 displays moderate cytotoxic effect on the cell growth in A549 cells. However, Ir-1, Ir-2 and Ir-3 were encapsulated in liposomes, the cytotoxic activity was greatly enhanced. In particular, Ir-1-Lipo and Ir-2-Lipo can effectively inhibit the cell growth in A549 cells with a low IC50 value of 3.1 ± 0.3 and 1.2 ± 0.4 µM. The apoptosis was assayed by flow cytometry. Ir-1, Ir-2 and Ir-3 reveal weak apoptotic effect, whereas Ir-1-Lipo, Ir-2-Lipo and Ir-3-Lipo induce an apoptotic percentage of 55.6%, 69.3% and 16.7% in A549 cells, respectively. Specially, in the assay of antitumor activity in vivo, the inhibiting percentage of tumor growth induced by Ir-2 is 27.65%, while inhibiting percentage of tumor growth caused by Ir-2-Lipo is 57.45%. Obviously, the liposomes can enhance anticancer activity in vitro and in vivo compared with the complexes. The results show that the iridium(III) complexes encapsulated liposomes induce apoptosis in A549 cells through ROS-mediated lysosome-mitochondria dysfunction pathway and target the microtubules.

Cloning, molecular characterization of a 13-kDa antigen from Schistosoma japonicum, Sj13, a putative salivary diagnosis candidate for Schistosomiasis japonica.

Saliva has been suggested as an easily accessible and a noninvasive diagnostic alternative for detection of antibodies. To identify and characterize Schistosoma japonicum (S. japonicum) antigens that are recognized by saliva of infected host, we have used a pool of saliva from infected patients to immunoscreen an egg cDNA library of S. japonicum. The open reading frame of the isolated two clones encodes same protein of 116 amino acids exhibiting 100% identity to an amino acid sequence (AY222893) of S. japonicum in NCBInr database. The protein encoded is inferred a secretory protein with a molecular mass of 13 kDa (Sj13) and shares no homology to any entries in the NCBInr database, demonstrating that Sj13 might be a schistosome-specific protein. Reverse transcriptase polymerase chain reaction, Western blotting, and immunolocalization analysis revealed Sj13 could be detected in cercaria, adult, and egg and was localized to forehead and tegument of cercaria, cell body ("cytons") of adult worm, egg shell, and epidermal plate of miracidium. Furthermore, Sj13 showed a good antigenicity when reacted with saliva or serum from schistosomiasis patients. The recombinant Sj13 (rSj13) expressed and purified from Escherichia coli was applied to detect its specific salivary antibody for schistosomiasis diagnosis by an indirect enzyme linked immunosorbent assay (ELISA). Preliminary laboratory test of 116 subjects, 40 with parasitologically proven S. japonicumm infection, 46 with other infectious diseases, and 30 negative controls exhibited 92.50% sensitivity with saliva/rSj13 and 95.00% with serum/SWAP (P > 0.05). The specificity of the ELISA using saliva/rSj13 was 92.11% versus 85.53% with serum/SWAP (P < 0.05). No direct correlations of anti-Sj13 IgG levels with egg counts in stool were observed in saliva detection. These results suggest that Sj13 specific salivary antibody detection may be useful as an antigen for the salivary diagnosis of schistosomiasis japonica and contribute to epidemiological study of schistosomiasis infection in endemic areas.

Studies of anticancer activity in vitro and in vivo of iridium(III) polypyridyl complexes-loaded liposomes as drug delivery system.

Two iridium(III) polypyridyl complexes [Ir(ppy)2(HPIP)](PF6) (Ir-1), [Ir(ppy)2(BHPIP)](PF6) (Ir-2) and their liposomes Ir-1-Lipo and Ir-2-Lipo were synthesized and characterized by elemental analysis, IR, 1H NMR and 13C NMR. The anticancer activity in vitro and in vivo was evaluated. The cytotoxic activity in vitro of the complexes and their liposomes Ir-1-Lipo and Ir-2-Lipo against cancer cells was investigated by MTT methods. Ir-1 and Ir-2 show no cytotoxic activity, while Ir-1-Lipo and Ir-2-Lipo exhibit high cytotoxic effect. The IC50 values range from 5.2 ±â€¯0.8 to 22.3 ±â€¯1.8 µM. The apoptosis, reactive oxygen species, the change of mitochondrial membrane potential, intracellular Ca2+ levels and a release of cytochrome c were investigated. The effect of Ir-1-Lipo and Ir-2-Lipo on microtubules was also explored. In the C57BL/6 mice model, Ir-1 only displays a tumor inhibitory rate of 23.21%, while lr-1-Lipo exhibits satisfactory in vivo antitumor efficacy with tumor inhibitory rate of 72.55%. This study demonstrates that complexes encapsulated in liposomes induce apoptosis in B16 through ROS-mediated lysosomal-mitochondria dysfunction, inhibition of polymerization of microtubules and induce cell cycle arrest at S phase.