Szygium aromaticum (L.) Merr. Et Perry (Myrtaceae) flower bud induces apoptosis of p815 mastocytoma cell line

Aqueous extract of Solanum nigrum inhibit growth of cervical carcinoma (U14) via modulating immune response of tumor bearing mice and inducing apoptosis of tumor cells

To explore the antitumor activity of aqueous extract of Solanum nigrum (SNL-AE) and its possible mechanism, we examined the effects of SNL-AE on the tumor growth in vivo, the number of CD4+, CD8+ T lymphocyte subsets of peripheral blood in tumor-bearing mice by means of FACScan flow cytometer, the expression of PCNA in U14 cervical carcinoma section by means of immunohistochemistry SP method, the cell cycle of transplanted tumor by means of FACScan flow cytometer and DNA fragmentation by means of agarose gel electrophoresis. Our results showed that SNL-AE could inhibit U14 cervical carcinoma growth and increased the number of CD4+ T lymphocyte subsets as well as the ratio of CD4+/CD8+ T lymphocyte, decreased the number of CD8+ T lymphocyte subsets of tumor-bearing mice and PCNA positive cells. Furthermore, it had the abilities to cause cell cycle arrest in G0/G1 phase and to induce apoptosis of more transplanted tumor cells in a dose-dependent manner. These results indicated that SNL-AE could suppress the cervical carcinoma via modulating immune response of the tumor-bearing mice and causing tumor cell cycle arrest in G0/G1 phase, as well as inducing apoptosis with little toxicity to the animals.

Antitumor activity of crude polysaccharides isolated fromSolanum nigrum Linne on U14 cervical carcinoma bearing mice

Solanum nigrum Linne (SNL) has been used in traditional Chinese medicine for centuries because of its diuretic and antipyretic effects. The present study examined the effect of the crude polysaccharides isolated from Solanum nigrum Linne (SNL-P) on tumor growth. SNL-P had a significant growth inhibition effect on cervical cancer (U14) of tumor-bearing mice. Further analysis of the tumor inhibition mechanism indicated that the number of apoptotic tumor cells increased significantly, the expression of Bax increased and the expression of Bcl-2 and mutant p53 decreased dramatically in cervical cancer sections after oral administration of SNL-P for 12 days. Moreover, SNL-P treatment decreased the level of blood serum TNF-alpha. These results indicated that the tumor growth inhibition of SNL-P administration might correlate with the reduction of TNF-alpha level of blood serum, which resulted in a massive necrosis in tumor tissues and the up-regulation of Bax and down-regulation of Bcl-2 and mutant p53 gene expression, which triggered apoptosis in tumor cells. These findings demonstrated that the SNL-P is a potential antitumor agent.

Phospho-ser 15-p53 translocates into mitochondria and interacts with Bcl-2 and Bcl-xL in eugenol-induced apoptosis

Our previous studies demonstrated that antiallergic effects of herbs such as clove and Magnoliae Flos (MF) resulted from the induction of apoptosis in mast cells. We here examined whether the antiallergic activity was caused by eugenol (4-allyl-2-methoxyphenol) which was one of major ingredients in the essential oils or extracts of numerous plants including clove and Magnoliae Flos. RBL-2H3 cells were treated with eugenol, and DNA electrophoresis, Western blotting, immunocytochemistry, confocal microscopy and immunoprecipitation were conducted. Effect of eugenol was tested using a rat anaphylaxis model. RBL-2H3 cells treated with eugenol showed typical apoptotic manifestations and translocation of p53 into mitochondria. Antisense p53 partially prevented the induction of apoptosis. Noticeably, we observed that p53 translocated into mitochondria was phosphorylated on ser 15. Phospho-ser 15-p53 physically interacted with Bcl-2 and Bcl-xL in mitochondria and its translocation into mitochondria preceded cytochrome c release and mitochondrial membrane potential (MMP) reduction. We also depicted that the survival of animals even after administration of the fatal dose of compound 48/80 might result from the decreased number of mast cells by eugenol pretreatment. In conclusion, eugenol induces apoptosis in mast cells via translocation of phospho-ser 15-p53 into mitochondria.

Pseudomonas aeruginosa exotoxin A induces human mast cell apoptosis by a caspase-8 and -3-dependent mechanism

Mast cells play an important role in both allergy and innate immunity. Recently, we demonstrated an active interaction between human mast cells and Pseudomonas aeruginosa leading to the production of multiple cytokines. Here, we show that both primary cultured human cord blood-derived mast cells and the human mast cell line HMC-1 undergo apoptosis as determined by single-stranded DNA (ssDNA) formation after stimulation with P. aeruginosa exotoxin A (ETA), a major toxin produced by this bacterium. ETA-induced ssDNA formation was completely inhibited by Z-VAD (where Z is benzyloxycarbonyl), which blocks multiple caspases, suggesting a role for caspases in this process. Active caspase-3 formation in mast cells after an ETA challenge was detected by both Western blotting and flow cytometry analysis. ETA-induced caspase-3 activity in human mast cells was demonstrated by the detection of a characteristic 23 kDa product of D4-GDI (where GDI is guanine nucleotide dissociation inhibitor), an endogenous caspase-3 substrate. Interestingly, a specific caspase-8 inhibitor, Z-IETD-fmk (where fmk is fluoromethyl ketone), blocked ETA-induced cleavage of D4-GDI, but a caspase-9 inhibitor (Z-LEHD-fmk) did not. Treatment of mast cells with caspase-3 inhibitor Z-DEVD-fmk or caspase-8 inhibitor Z-IETD-fmk reduced the generation of ssDNA induced by ETA, suggesting a role for caspase-8 and -3 in ETA-induced mast cell apoptosis. Furthermore, treatment of mast cells with ETA induced decreases of the short form and a long form (p43) of Fas-associated death domain protein (FADD)-like interleukin-1beta-converting enzyme (FLICE) (caspase-8)-inhibitory proteins (FLIPs), which are endogenous caspase-8 inhibitors. Taken together, these results suggest that ETA-induced mast cell apoptosis involves down-regulation of antiapoptotic proteins, FLIPs, and activation of caspase-8 and -3 pathways.

Magnoliae flos induces apoptosis of RBL-2H3 cells via mitochondria and caspase

BACKGROUND

Magnoliae flores (MF), the buds of Magnolia denudata Desrousseaux, have been successfully used for the management of allergic diseases in Korea. The purpose of the present study was to determine their causal role in inducing apoptosis of mast cells and to verify the underlying mechanism.

METHODS

The viability of mast cells was assessed by the trypan blue exclusion test. Induction of apoptosis was confirmed by DNA fragmentation, nuclear staining and DNA hypoploidy. Western blotting and immunofluorescent staining were performed to study the alterations in expression level and translocation of apoptosis-related proteins. Mitochondrial membrane potential (MMP) change and cytochrome C release were assayed.

RESULTS

We present several lines of evidence indicating that MF induce apoptosis. Changes in cell morphology, generation of DNA fragmentation, cell cycle arrest, activation of caspase-3, and PARP and DFF degradations were demonstrated. The reduction of MMP and the release of cytochrome C to cytosol were also shown. Either PTP blockers, bongkrekic acid and cyclosporin A, or pancaspase inhibitors, Boc.D-fmk and zVAD-fmk, did not prevent the release of cytochrome C. Bax protein content was increased, and Bax was translocated from cytosol into mitochondria at early time points after MF treatment.

CONCLUSIONS

We have demonstrated that MF induce mitochondria- and caspase-dependent mast cell apoptosis. Our observations contribute new insights to the role of MF and support the view that the clinical effect of MF may depend on their pharmacological efficacy in regulating mast cell apoptosis.

Genistein-induced apoptosis of p815 mastocytoma cells is mediated by Bax and augmented by a proteasome inhibitor, lactacystin

Although genistein has been demonstrated to induce apoptosis of various cells, there is no report of its effect on mast cell proliferation. Here we show that genistein reduced the viability of mast cell tumor cell lines, p815 and RBL-2H, but not of a human mast cell line, HMC-1. Further investigation on its growth-inhibitory mechanism was undertaken on p815 mastocytoma cells. Genistein induced G2/M arrest and subsequent apoptotic death. p815 cells undergoing apoptosis showed many apoptotic manifestations, such as reduction of mitochondrial membrane potential, release of cytochrome c to cytosol, translocation of apoptosis-inducing factor to nucleus, activation of caspase-3, nuclear condensation, and generation of DNA fragmentation. Genistein treatment resulted in the increase of Bax expression and its translocation into mitochondria, whereas expression levels of Bcl-2 remained unchanged. Proteasome activity decreased at the early time points after genistein treatment, but thereafter it fluctuated at increased levels. A proteasome inhibitor, lactacystin, potentiated the induction of apoptosis. Taken together, genistein-induced apoptosis of p815 mastocytoma cells is at least in part mediated by proteasome, Bax, apoptosis-inducing factor, and caspase and augmented by cotreatment with a proteasome inhibitor, lactacystin.

Anticancer activity of Hemsleya amabilis extract

Hemsleya amabilis extract is derived from the medicinal herb Hemsleya amabilis, which has long been used to treat cancer and many other conditions. The underlying mechanism is not clear. To investigate Hemsleya amabili's anticancer activity, we have treated different types of cancer cells including human astrocytoma U87 cells, breast cancer cells MDA-MB-231and Jurkat cells with Hemsleya amabilis extract. This agent significantly inhibited tumor cell growth and colony formation at various concentrations. When astrocytoma cells were seeded in the presence of Hemsleya amabilis extract at very low concentrations, cell spreading was greatly inhibited. Hemsleya amabilis extract also promoted tumor cell death in all the tested cell lines, but with varied sensitivities. Apoptotic assays with Annexin V staining demonstrated that Hemsleya amabilis extract induced astrocytoma cell apoptosis at different concentrations.