Biomedical subjects
Publications and source records attributed to Manabu Hatano.
A cationic rhodium(I) complex having a skewphos ligand is shown to be a highly enantioselective catalyst for asymmetric carbocyclization of 1,6-enynes with tri-substituted olefins to control quaternary stereogenic centers of spiro-rings.
The first highly enantioselective synthesis of a six-membered ring quinoline catalyzed by a cationic BINAP-palladium(II) complex is shown to afford the quinoline products having a quaternary carbon center or a spiro-ring in quantitative yield and >99% ee.
The racemic Pd complexes with chirally flexible (tropos) biphenylphosphine (BIPHEP) ligands can be resolved but transformed into the enantio- and diastereo-pure complex. The enantiopure metal complex of BIPHEP ligand is thus obtained through enantiomer-selective complexation of a racemic BIPHEP-Pd complex with enantiopure 1,1'-binaphthyl-2,2'-di(triflyl)amide, DABNTf. The differential CD spectra of the enantiopure BIPHEP-Pd complex is also reported.
PURPOSE: Immunotherapy is the most effective treatment against metastatic renal cell carcinoma (RCC). However, the response rate is approximately 15%. More effective therapy is, therefore, needed for patients with metastatic RCC. We then examined the antitumor effect of cationic multilamellar liposome containing human IFN-beta (huIFN-beta) gene (IAB-1) against RCC. EXPERIMENTAL DESIGN: Concentrations of huIFN-beta protein were measured by ELISA. The cytotoxicity of IAB-1 against human RCC (NC65, ACHN, and freshly isolated RCC cells), prostate and bladder cancer cell lines, and renal proximal tubule endothelial cells (RPTEC5899) was examined by the colorimetric method using tetrazolium salt. Apoptosis was assessed by the acridine-orange staining. For in vivo study, we used NC65 cells inoculated into severe combined immunodeficiency mouse. RESULTS: The RCC cells treated with IAB-1 secreted significant amounts of huIFN-beta protein continuously. Drastic in vitro cytotoxic effect of IAB-1 against RCC was observed. In contrast, treatment with 1000 IU/ml recombinant huIFN-beta protein resulted in weak cytotoxicity. The cytotoxic effect against prostate and bladder cancer cell lines was less than that against RCC. Furthermore, no significant cytotoxicity was observed in RPTEC5899 cells. Apoptosis was observed in the cells treated with IAB-1, but recombinant huIFN-beta failed to induce apoptosis. The size of NC65 tumors transfected with IAB-1 in mice was significantly smaller than that receiving injection of empty liposome or recombinant huIFN-beta protein. CONCLUSION: These findings indicate that IAB-1 may have an antitumor activity against human RCC by inducing apoptosis, suggesting its potential clinical application for gene therapy against RCC.
Brain tumors generally arise as the culmination of a multistep process that involves a variety of genetic abnormalities. Theoretically, replacement of abnormal genes with normal genes is essential to brain tumor treatment. However, it is very difficult to replace all damaged genes. Currently, most clinical protocols for gene therapy in brain tumors include transfer of a gene which can induce tumor cells to die or which can enhance the environment to generate a systemic immune response against the tumor. The former strategy includes suicide gene therapies, tumor suppressor gene therapy and oncolytic virus therapy. The latter adopts immunogene therapy. In this report, we also focus on other gene therapies, such as therapies to control the cell cycle or apoptosis, and promote antiangiogenesis. Gene therapy is generally accepted to be rather safe in recent years. In fact, the current single-gene therapies for brain tumor are limited and probably restricted to a few tumors. Several agents with different mechanisms of action would be necessary to kill heterogenously mixed tumor cells. Further molecular techniques and basic studies may overcome the malignancy of cancers.
[reaction: see text] The racemic Pd complex with the chirally flexible (tropos) biphenylphosphine (BIPHEP) ligand can be resolved with enantiopure 3,3'-dimethyl-2,2'-diamino-1,1'-binaphthyl (DM-DABN) as a resolving agent at room temperature. The enantiopure BIPHEP-Pd complex is obtained from complexation with enantiopure DABN followed by tropo-inversion into the single BIPHEP-Pd diastereomer at 80 degrees C and protonation at 0 degrees C. The enantiopure BIPHEP-Pd complex can be used as an efficient Lewis acid catalyst for the Diels-Alder reaction at room temperature to give high enantioselectivity (82% ee, 60%).
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