Boc-Asp-OMe

We examined the effects of the cell-permeable, broad spectrum peptide caspase inhibitors, benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD.fmk), and BOC-Asp(OMe)-fluoromethyl ketone (BOC-D.fmk), on apoptosis induced by anti-CD2, anti-Fas, and the protein kinase inhibitor staurosporine in activated human peripheral T lymphocytes. We monitored ultrastructural, flow cytometric, and biochemical apoptotic changes, including externalization of phosphatidylserine, cleavage of poly(ADP-ribose) polymerase (PARP) and lamins, activation of caspase-3 and caspase-7, decrease in mitochondrial membrane potential, and DNA fragmentation. Z-VAD.fmk and BOC-D.fmk completely inhibited all the biochemical and ultrastructural changes of apoptosis in anti-Fas-treated cells. In marked contrast, neither Z-VAD.fmk nor BOC-D.fmk inhibited CD2- or staurosporine-mediated cell shrinkage, dilatation of the endoplasmic reticulum (seen in anti-CD2-treated cells), externalization of phosphatidylserine, and loss of mitochondrial membrane potential that accompanied cell death. However, these inhibitors did inhibit the cleavage of PARP and lamins and the formation of hypodiploid cells, and partially inhibited chromatin condensation. These results demonstrate that in activated T cells, anti-CD2 and staurosporine induce a caspase-independent cell death pathway that exhibits prominent cytoplasmic features of apoptosis. However, caspase activation is required for the proteolytic degradation of nuclear substrates such as PARP and lamins together with the DNA fragmentation and extreme chromatin condensation that occur in apoptotic cells.

(-)-Anonaine has been shown to have some anticancer activities, but the mechanisms of (-)-anonaine inducing cell death of human cancer cells is not fully understood. We investigated the mechanisms of apoptosis induced by (-)-anonaine in human HeLa cancer cells. Treatment with (-)-anonaine induces dose-dependent DNA damage that is correlated with increased intracellular nitric oxide, reactive oxygen species, glutathione depletion, disruptive mitochondrial transmembrane potential, activation of caspase 3, 7, 8, and 9, and poly ADP ribose polymerase cleavage. Our data indicate that (-)-anonaine up-regulated the expression of Bax and p53 proteins in HeLa cancer cells. The apoptosis and expression of Bax induced by (-)-anonaine could be inhibited when the HeLa cells were pretreated with Boc-Asp(OMe)-fmk, which is a broad caspases inhibitor. There was no obvious DNA damage in the (-)-anonaine-treated Madin-Darby canine kidney and Vero cell lines. Both Madin-Darby canine kidney and Vero cell lines are kidney epithelial cellular morphology. These results suggest that (-)-anonaine might be considered a potent compound for chemotherapy against cervical cancer or a health food supplement for cancer chemoprevention.

In the title homotripeptide {Boc-[Asp(OMe)]3-OPac}, C28H37N3O13, all peptide bonds adopt an s-trans conformation with respect to the N-H and C=O groups. In the crystal, N-H⋯O hydrogen bonds result in an infinite parallel β-sheet structure running along the b-axis direction. The Boc protecting group at the N-terminus of the peptide is disordered over two sites with occupancy factors of 0.504 (5) and 0.496 (5).