Mechanisms of grape seed procyanidin-induced apoptosis in colorectal carcinoma cells.

BACKGROUND: Grape seed procyanidins (GSP) can inhibit cell proliferation and tumorigenesis, and induce apoptosis in human breast, prostate, skin and colorectal carcinoma cell lines. MATERIALS AND METHODS: In order to study the mechanism of apoptosis, four colorectal cell lines, HT-29, SW-480, LoVo and Colo 320DM, were used. GSP-treated cells were assessed for viability by trypan blue exclusion, for loss of mitochondrial membrane potential by rhodamine 123 staining, for increased apoptosis by annexin V labeling, and for changes in the levels of proteins involved in apoptosis by immunoblotting. RESULTS: GSP had no significant pro-apoptotic effect on the Colo 320DM cell line. In HT-29, SW-480 and LoVo cells, GSP (12.5-50 mg/l) inhibited proliferation in a dose-dependent manner. In these three lines, GSP treatment increased the proportion of rhodamine 123-negative cells and annexin V-positive cells, while immunoblotting revealed increased levels of apoptosis activation protein, caspase-3 and the cleavage fragment of PARP (a caspase-3 substrate), but the level of Bcl-2 did not change. CONCLUSION: GSP inhibited the proliferation of some colorectal carcinoma cell lines and was associated with an apoptotic mechanism involving a loss of mitochondrial membrane potential and caspase-3 activation in these cells.

GA3, a new gambogic acid derivative, exhibits potent antitumor activities in vitro via apoptosis-involved mechanisms.

AIM: Gambogic acid (GA) is the major active ingredient of gamboge, which is secreted from a Chinese traditional medicine, Garcinia hanburyi, which possesses potent antitumor activity. GA3, a new GA derivative, has been shown to possess better water solubility than GA. The aim of the present study was to examine the antitumor activity of GA3 and the mechanism underlying it. METHODS: The growth inhibition of cancer cell lines induced by GA3 was assessed using the SRB assay. DAPI staining, flow cytometry, a DNA fragment assay, and Western blot analysis were used to study the apoptotic mechanisms of GA3. RESULTS: GA3 displayed wide cytotoxicity in diversified human cancer cell lines with a mean IC(50) value of 2.15 micromol/L. GA3 was also effective against multidrug resistant cells, with an average resistance factor (RF) that was much lower than that of the reference drug, doxorubicin. Mechanistic studies revealed that GA3-induced apoptosis in HL-60 cells proceeded via both extrinsic and intrinsic pathways, with caspase-8 functioning upstream of caspase-9. In addition, GA3-driven apoptotic events were associated with up-regulation of Bax, down-regulation of Bcl-2 and cleavage of Bid. Moreover, GA3 triggered cytochrome c release from the mitochondria, in particular bypassing the involvement of the mitochondrial membrane potential. CONCLUSION: Better solubility and a potential anti-MDR activity, combined with a comparable antitumor efficacy, make GA3 a potential drug candidate in cancer therapy that deserves further investigation.

Alpinia pricei rhizome extracts induce apoptosis of human carcinoma KB cells via a mitochondria-dependent apoptotic pathway.

Alpinia pricei Hayata (A. pricei) is well known in Taiwan as a traditional Chinese medicine. In this study, the ability of ethanol (70%) extracts of A. pricei rhizome (AP extracts) to induce apoptosis in cultured human carcinoma KB cells was investigated. Treatment of KB cells with various concentrations of AP extracts (25-200 microg/mL) resulted in sequences of events marked by apoptosis, such as loss of cell viability, morphology change, and internucleosomal DNA fragmentation. AP extract-induced apoptotic cell-death was associated with loss of mitochondrial membrane potential, cytochrome c translocation, caspase-3 and -9 activation, and poly ADP-ribose polymerase (PARP) degradation in KB cells. This increase in AP extract-induced apoptosis was also associated with a reduction in the levels of Bcl-2, a potent cell-death inhibitor, and an increase in levels of the Bax protein, which heterodimerizes with and thereby inhibits Bcl-2. Furthermore, AP extracts induced a dose-dependent elevation of reactive oxygen species (ROS) in KB cells. Our findings suggest that A. pricei exerts antiproliferative action and growth inhibition on human carcinoma KB cells through a mitochondria-dependent apoptotic pathway. A. pricei may, therefore, have anticancer properties valuable for application in food and drug products.

Induction of apoptosis by KI0477959 through activation of caspase-3 in human leukemia cell line, HL-60 cells.

KI0477959 (Herbkines) has been used for the purpose of development of physical strength in wasting diseases, like cancer. In the present study, apoptosis-inducing activities of butanol fraction of KI0477959 were studied in human leukemia cell line, HL-60 cells. KI0477959 increased cytotoxicity but had less effect on human peripheral blood mononuclear cells. KI0477959-induced apoptosis was accompanied by activation of caspase-3 and specific proteolytic cleavage of poly-ADP-ribose polymerase. Increased apoptosis was reduced by treatment with p38 and extracellular signal-regulated protein kinase (ERK) inhibitors. These results suggest that KI0477959 induces apoptosis through activation of caspase-3, p38, and ERK in HL-60 cells.

Thioredoxin upregulation by 5-aminolaevulinic acid-based photodynamic therapy in human skin squamous cell carcinoma cell line.

BACKGROUND/PURPOSE: 5-aminolaevulinic acid-based photodynamic therapy (ALA-PDT) is widely performed in the clinical setting for superficial skin cancers, giving favorable results, but residual tumor and recurrence occur occasionally. Thioredoxin is a common antioxidant that suppresses apoptosis and facilitates cell growth. We investigated the expression of thioredoxin following ALA-PDT in human skin squamous cell carcinoma cell line, HSC-5. METHODS: ALA-PDT was performed in HSC-5 cells using low-dose (5 J/cm(2), 100 mW/cm(2)) or high-dose (30 J/cm(2), 100 mW/cm(2)) irradiation, and the expression of thioredoxin was measured by Western blotting. An MTT assay was used to assess cell growth following a low dose of multiple irradiations. Cell death was examined by Western blotting for caspase-3 and PARP. Immunofluorescence double staining using annexin V and propidium iodine was also performed. RESULTS: Expression of thioredoxin was only observed following low-dose exposure ALA-PDT. Multiple low-dose exposure ALA-PDT significantly proliferated cell growth. With high-dose exposure ALA-PDT, caspase-3 and PARP expression were seen, and cell death due to apoptosis and/or necrosis was observed, but thioredoxin was barely detected. CONCLUSION: Low-dose exposure ALA-PDT increased the expression of thioredoxin and facilitated the growth of HSC-5 cells.

Synergistic tumor-killing effect of radiation and berberine combined treatment in lung cancer: the contribution of autophagic cell death.

PURPOSE: Radiotherapy is the most efficacious strategies for lung cancer. The radiation-enhancing effects and the underlying mechanisms of berberine were investigated both in vitro and in vivo. METHODS AND MATERIALS: Clonogenic survival assays were used to evaluate the radio-sensitivity of berberine on non-small-cell lung cancer. Electron microscopic observation of the features of cell death, flow cytometry of acidic vascular organelles formation, mitochondria membrane potential and cell-cycle progression, and Western blotting of caspase 3, PARP, and LC3 were performed to identify the mechanisms underlying the enhancing effects. Lewis lung carcinoma model in mice was conducted to evaluate the possible application of berberine in synergistic treatment with irradiation. RESULTS: Compared with radiation alone (SF2 = 0.423; D(0) = 5.29 Gy), berberine at 5 and 10 muM concentrations in combination with radiation showed significant enhancement on radiation-induced clonogenic inhibition (SF2 = 0.215: D(0) = 2.70 Gy and SF2 = 0.099: D(0) = 1.24 Gy) on A549 cells. The cellular ultrastructure showed the presence of autophagosome and an increased proportion of acridine orange stain-positive cells, demonstrating that berberine enhanced radiosensitivity via autophagy. The process involved LC3 modification and mitochondrial disruption. The animal model verified the synergistic cytotoxic effect of berberine and irradiation resulting in a substantial shrinkage of tumor volume. CONCLUSION: Supplement of berberine enhanced the cytotoxicity of radiation in both in vivo and in vitro models of lung cancer. The mechanisms underlying this synergistic effect involved the induction of autophagy. It suggests that berberine could be used as adjuvant therapy to treat lung cancer.

Thiosulfinates from Allium tuberosum L. induce apoptosis via caspase-dependent and -independent pathways in PC-3 human prostate cancer cells.

This study was aimed to evaluate the apoptotic effects of thiosulfinates purified from Allium tuberosum L. on PC-3 human prostate cancer cells, and to elucidate detailed apoptosis mechanisms. Thiosulfinates significantly decrease viable cell numbers in dose- and time-dependent manners by apoptotic cell death via DNA fragmentation, chromatin condensation, and an increased sub-G1 phase. Apoptosis induced by thiosulfinates is associated with the activation of initiator caspase-8 and -9, and the effector caspase-3. In this study, thiosulfinates stimulated Bid cleavage, indicating that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. Thiosulfinates decreased the expression of the anti-apoptotic protein Bcl-2 and increased the expression of the pro-apoptotic protein Bax. Thiosulfinates also increased the expression of AIF, a caspase-independent mitochondrial apoptosis factor, in PC-3 cells. These results indicate that thiosulfinates from A. tuberosum L. inhibit cell proliferation and induce apoptosis in PC-3 cells, which may be mediated via both caspase-dependent and -independent pathways.

Apoptosis of T-leukemia and B-myeloma cancer cells induced by hyperbaric oxygen increased phosphorylation of p38 MAPK.

Tumor cells with different origins have different threshold to apoptosis. Hematopoietic (Jurkat, NCI-H929) cells and non-hematopoietic (A549, MCF-7) cells were received hyperbaric oxygen (HBO(2)) treatment from 2.5 to 3.5 atmosphere absolute (ATA) of 100% oxygen for 6h, and a significant percentage of apoptosis were shown only in hematopoietic Jurkat and NCI-H929 cells by either Annexin V or TUNEL assay. Oxidative stress was illustrated higher in HBO(2)-treated hematopoietic cells by superoxide fluorochrome detectors. HBO(2) treatment leads to caspase-3, caspase-7 activation and further cleavage of PARP within cells. Furthermore, the increased phosphorylation of p38 MAPK was demonstrated in both Jurkat and NCI-H929 cells.

Siegesbeckia glabrescens induces apoptosis with different pathways in human MCF-7 and MDA-MB-231 breast carcinoma cells.

Breast cancer is one of the most common malignancies diagnosed in women and it is increasing in incidence. Siegesbeckia glabrescens (SG) has been used in traditional oriental medicine to treat cardiovascular diseases such as hypertension and angina pectoris. This study examined whether or not SG could induce apoptosis in human breast carcinoma cells. The treatment of estrogen-receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) cells with a variety of SG concentrations (0-1.0 mg/ml) resulted in a dose-dependent sequence of events that were marked by apoptosis. Furthermore, this apoptosis was accompanied by the cleavage of procaspase-9 and -3, and poly(ADP-ribose) polymerase (PARP) in the MCF-7 cells, and procaspase-8 and -3 and PARP in the MDA-MB-231 cells. Although, the SG-induced apoptosis was associated with a decrease in the level of Bcl-2 mRNA expression and an increase in the level of Bax mRNA expression in MCF-7 cells, there was no detectable change in the MDA-MB-231 cells. This suggests that SG might exert anti-proliferative action in human breast carcinoma cells via two different apoptotic pathways, namely an intrinsic signal in MCF-7 cells and an extrinsic signal in MDA-MB-231 cells. Therefore, regardless of the ER status, SG might be a promising pro-apoptotic agent for treating breast cancer.