Extracellular Leakage Protein Patterns in Two Types of Cancer Cell Death: Necrosis and Apoptosis.

Dead cells release fragments of DNA, RNA, and proteins (including peptides) into the extracellular space. Two major forms of cell death during cancer development have been identified: necrosis and apoptosis. Our group investigated the mechanisms that regulate cell death during the treatment of mouse tumor FM3A cells with the anticancer drug floxuridine (FUdR). In the original strain F28-7, FUdR induced necrosis, whereas in the variant F28-7-A, it induced apoptosis. Here, we report that the extracellular leakage proteome (i.e., the secretome) is involved in these cell death phenomena. The secretome profile, which was analyzed via shotgun proteomic analysis, revealed that altered protein leakage was involved in signal transduction, transcription, RNA processing, translation, and cell death. Notably, the characteristic secretory proteins high mobility group box 1 and 2 were detected in the culture medium of both necrotic and apoptotic cells. Overall, these results indicate that unique cellular events mediated by secretory proteins may be involved in necrosis and apoptosis.

α-Heteroarylation of ketones via the umpolung reaction of N-alkoxyenamine.

A new method has been developed for the umpolung α-heteroarylation of ketones via an N-alkoxyenamine. The treatment of ketones with tris(heteroaryl)aluminum reagents in the presence of isoxazolidine gave the corresponding α-heteroarylated ketones in moderate to good yields.

Michael addition-aromatization reaction of dienylimines bearing a leaving group and its application to the preparation of thiol-selective labeling reagents capable of forming strong carbon-sulfur bonds.

The reaction of a dienylimine with thiols was found to proceed smoothly to afford the corresponding indolines bearing aromatic carbon-sulfur bonds as a result of a Michael addition-aromatization sequence. Furthermore, this reaction was applied to the development of fluorogenic dienylimines that could be used as thiol-selective fluorescent labeling reagents.

Sequential retro-ene arylation reaction of N-alkoxyenamides for the synthesis of tert-alkylamines.

A sequential retro-ene arylation reaction has been developed for the conversion of N-alkoxyenamides to the corresponding tert-alkylamines in good yields via the nucleophilic addition of a triarylaluminum reagent to an in situ generated N-acylketimine. The reaction is tolerant of a range of functional groups and provides facile access to a series of tert-alkylamines that would be otherwise difficult to access using conventional procedures.

Rhodamine-labeled LDL as a tool to monitor the lipoprotein traffic in experimental model of early atherosclerosis in mice.

Modifications of proteoglycans, subendothelial retention of low-density lipoproteins (LDL) and their subsequent oxidation initiate the development of atherosclerosis. Therefore, detection of lipoprotein entrapment in the arterial wall is an important feature for the analysis of the mechanisms of atherosclerosis. The administration of fluorescent-labeled LDL in vivo is a breakthrough way to assess the traffic of LDL in the arterial wall. The present study demonstrated the feasibility of visualizing LDL in carotid ligation-induced intimal thickening of arterial wall after intravenous rhodamine-labeled LDL injection in mice. Kinetics of rhodamine-labeled LDL showed similar characteristics as native LDL and labeled-LDL could be detected both by spectrophotometric and microscopic analysis. Kinetics analysis of rhodamine-labeled LDL revealed that the labeled LDL was present in almost all tissue, predominantly in the liver, 6 hours after injection. Rhodamine-labeled LDL was visualized in intimal thickening of carotid 6 to 18 hours after injection, indicating that the LDL was actively trapped in the arterial wall. In conclusion, rhodamine-labeled LDL would be a useful tool to investigate the development of atherosclerosis.

Copper-catalyzed synthesis of trisubstituted isoxazoles via a cascade cyclization-migration process.

An atom-economical, catalytic, and regioselective synthesis of 3,4,5-trisubstituted isoxazoles has been successfully developed. Treatment of O-arylmethyl alkynyl oxime ethers with 5 mol % of Cu(OTf)(2) in chlorobenzene at reflux gave 4-arylmethylisoxazoles in good to excellent yields via the sequential intramolecular addition of the oxime moiety to the alkyne with subsequent 1,3-migration of the arylmethyl group.

Palladium-catalyzed cross coupling reaction of N-alkoxyimidoyl bromides and its application to one-pot synthesis of N-arylamines.

The synthetic utility of N-alkoxyimidoyl halides is demonstrated using the palladium-catalyzed cross-coupling reaction. The Sonogashira and Suzuki-Miyaura coupling reactions of N-alkoxyimidoyl bromides produced versatile ketoxime ethers in good to excellent yields. A one-pot reaction of the imidoyl bromides with arylboronic acid and allylmagnesium bromide to produce N-arylamines via Suzuki-Miyaura coupling followed by domino reaction involving sequential addition-eliminative rearrangement-addition reactions was developed.

Benzyl radical addition reaction through the homolytic cleavage of a benzylic C-H bond.

Direct generation of a benzyl radical by C-H bond activation of toluenes and the addition reaction of the resulting radical to an electron deficient olefin were developed. The reaction of dimethyl fumarate with toluene in the presence of Et(3)B as a radical initiator at reflux afforded 2-benzylsuccinic acid dimethyl ester in good yield.

Direct synthesis of trisubstituted isoxazoles through gold-catalyzed domino reaction of alkynyl oxime ethers.

Alkynyl oxime ether underwent a gold-catalyzed domino reaction involving cyclization and subsequent Claisen-type rearrangement to afford trisubstituted isoxazoles in a direct, efficient, and regioselective manner. The products were successfully applied to the synthesis of unusual heterocycles as an illustration of the potential utility of the reaction.

Design and chemical synthesis of a 2',4'-BNA probe for 7,8-dihydro-8-oxoguanine-containing double stranded DNA.

7,8-Dihydro-8-oxoguanine (8-OxoG), caused by DNA oxidation, is considered to be a marker of oxidative stress, and also to be a cause of genomic diversity in organism because of its mutagenic potential. Here, we designed and synthesized a 2',4'-BNA probe for 8-OxoG-containing double stranded DNA (dsDNA). The designed probe showed an 8-OxoG:C base pair selective triplex-forming ability.