Highly congested vicinal all-carbon quaternary stereocenters were generated via catalytic asymmetric alkylation reaction of 3-bromooxindoles with 3-substituted indoles. These catalytic reactions proceeded in excellent yields with a broad scope on either reaction partner, and with outstanding diastereo- and enantiocontrol. The newly developed method led to the total synthesis of (+)-perophoramidine in a highly efficient manner.

The catalytic asymmetric amination reaction of 3-bromooxindoles with indolines for the construction of the N1-C3 linkage stereogenic centers has been realized for the first time. Moreover, the racemic substrates (3-substituted indolines) were also applicable under the same chiral conditions. The newly developed method conveniently led to a formal synthesis of (+)-psychotrimine.

There is a growing interest in the fact that mechanical signals may be as important as biological signals in evaluating cell viability. To investigate the alterations in biomechanics, nanomorphology and biological apoptotic signals during early apoptosis, an apoptosis model was established for cervical cancer HeLa cells induced by cytochalasin B (CB). The cellular mechanical properties, geometry, morphology and expression of key apoptotic proteins were systematically analyzed. The findings indicated a marked decline in cellular elastic modulus and volume and a considerable increase in surface roughness occurring prior to the activation of biological apoptosis signals (such as phosphatidylserine exposure or activation of CD95/Fas). Moreover, the depolymerization of filamentous actin aggravated the intracellular crowding degree, which induced the redistribution of different-sized protein molecules and protrusions across the cell membrane arising from excluded volume interactions. Statistical analysis revealed that the disassembly of the actin cytoskeleton was negatively correlated with the cellular elastic modulus and volume, but was positively correlated with surface roughness and CD95/Fas activation. The results of the present study suggest that compared with biological signals, mechanical and geometrical reconstruction is more sensitive during apoptosis and the increase in cell surface roughness arises from the redistribution of biophysical molecules. These results contribute to our in-depth understanding of the apoptosis mechanisms of cancer cells mediated by cytochalasin B.

BackgroundNasopharyngeal carcinoma (NPC) is well-known for its highly metastatic characteristics, but little is known of its molecular mechanisms. New biomarkers that predict clinical outcome, in particular the ability of the primary tumor to develop metastatic tumors are urgently needed. The aim of this study is to investigate the role of FLJ10540 in human NPC development.MethodsA bioinformatics approach was used to explore the potentially important regulatory genes involved in the growth/metastasis control of NPC. FLJ10540 was chosen for this study. Two co-expression strategies from NPC microarray were employed to identify the relationship between FLJ10540 and osteopontin. Quantitative-RT-PCR, immunoblotting, and immunohistochemistry analysis were used to investigate the mRNA and protein expression profiles of FLJ10540 and osteopontin in the normal and NPC tissues to confirm microarray results. TW01 and Hone1 NPC cells with overexpression FLJ10540 or siRNA to repress endogenous FLJ10540 were generated by stable transfection to further elucidate the molecular mechanisms of FLJ10540-elicited cell growth and metastasis under osteopontin stimulation.ResultsWe found that osteopontin expression exhibited a positive correlation with FLJ10540 in NPC microarray. We also demonstrated comprehensively that FLJ10540 and osteopontin were not only overexpressed in NPC specimens, but also significantly correlated with advanced tumor and lymph node-metastasis stages, and had a poor 5-year survival rate, respectively. Stimulation of NPC parental cells with osteopontin results in an increase in FLJ10540 mRNA and protein expressions. Functionally, FLJ10540 transfectant alone, or stimulated with osteopontin, exhibited fast growth and increased metastasis as compared to vehicle control with or without osteopontin stimulation. Conversely, knockdown of FLJ10540 by siRNA results in the suppression of NPC cell growth and motility. Treatment with anti-CD44 antibodies in NPC parental cells not only resulted in a decrease of FLJ10540 protein, but also affected the abilities of FLJ10540-elicited cell growth and motility in osteopontin stimulated-NPC cells.ConclusionsThese findings suggest that FLJ10540 may be critical regulator of disease progression in NPC, and the underlying mechanism may involve in the osteopontin/CD44 pathway.