acetyl-aspartyl-glutamyl-valyl-aspartal and Stomach-Neoplasms

Raltitrexed is a specific inhibitor of thymidylate synthase (TS), which has been considered as a potential chemotherapeutic agent for the treatment of advanced gastric cancer. In the present study, the apoptosis mechanisms of raltitrexed in SGC7901 human gastric cancer cells were investigated. The cytotoxic activity of raltitrexed on SGC7901 cells was determined by cell counting kit-8 (CCK-8) assay. The CCK‑8 assay indicated that raltitrexed inhibits SGC7901 cell growth in a dose- and time-dependent manner. The morphological changes were observed by fluorescent microscopy, and characteristic morphological changes, including nuclear shrinkage and apoptotic bodies, were observed following Hoechst 33258 staining. The effects on apoptosis, cell cycle, mitochondrial transmembrane potential and reactive oxygen species (ROS) were measured by flow cytometry. The analysis revealed that raltitrexed exerted a growth inhibitory effect by inducing time-dependent apoptosis and cell-cycle arrest at the G0/G1 phase. In addition, a compromised mitochondrial membrane potential and overproduction of ROS demonstrated the involvement of the mitochondrial signaling pathway. Raltitrexed‑induced caspase‑3‑dependent apoptosis was identified using a caspase-3 activity assay and pretreatment with the caspase-3 inhibitor, Ac‑DEVD‑CHO (sequence, Ac-Asp-Glu-Val-Asp-CHO). The activity of caspase-3 was analyzed with a spectrometer. The protein expression levels of Bax, Bcl-2, cytochrome c, cleaved caspase-3 and TS were examined by western blot and the mRNA expression level of TS was detected by quantitative polymerase chain reaction. The analysis revealed that the protein levels of Bax, cytochrome c and cleaved caspase‑3 were significantly increased by raltitrexed, while Bcl-2 expression levels were reduced. Furthermore, raltitrexed increased the expression of the TS protein and mRNA in a time‑dependent manner. These results indicate that raltitrexed induces the apoptosis of SGC7901 cells through the caspase‑3‑dependent mitochondrial signaling pathway and upregulates the expression of the TS protein and mRNA.

Topics: Antimetabolites, Antineoplastic; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Cell Line, Tumor; Cytochromes c; G1 Phase Cell Cycle Checkpoints; Humans; Membrane Potential, Mitochondrial; Mitochondria; Oligopeptides; Proto-Oncogene Proteins c-bcl-2; Quinazolines; Reactive Oxygen Species; RNA, Messenger; Signal Transduction; Stomach Neoplasms; Thiophenes; Thymidylate Synthase

Garlic and the organosulfer compound from garlic have antitumor effects, but the mechanisms still remain unclear. This study was to investigate the changes and significance of caspase-3 activity in diallyl trisulfide (DATS)-induced apoptosis of human gastric cancer cell line MGC803.. Effects of DATS on the apoptosis of MGC803 cells and the change of activated caspase-3 were observed under a fluorescent and an electron microscopy, and detected by flow cytometry and Western blot.. After incubation with DATS, MGC803 cells showed typical apoptotic morphologic changes, and the apoptosis rate increased significantly. DATS activated caspase-3 in a time-dependent manner: the positive rates of activated caspase-3 were 1.9%, 3.0%, 7.3%, 14.4%, and 27.6% respectively in MGC-803 cells treated with 12 mg/L DATS for 0, 4, 8, 12 and 24 h. When treated with 12 mg/L DATS for 24 h, the apoptosis rate was significantly lower in the cells with pretreatment of Ac-DEVD-CHO (a caspase-3 inhibitor) than in the cells without pretreatment (5.1% vs. 23.0%, P<0.01), indicating that Ac-DEVD-CHO efficiently attenuated DATS-induced apoptosis of MGC803 cells. Moreover, pro-caspase-3 was hydrolyzed and activated in DATS-treated MGC803 cells.. DATS induces apoptosis in MGC803 cells which may be through the activation of caspase-3 pathway.

Topics: Adenocarcinoma, Mucinous; Allyl Compounds; Antineoplastic Agents, Phytogenic; Apoptosis; Caspase 3; Caspase Inhibitors; Cell Line, Tumor; Enzyme Activation; Garlic; Humans; Oligopeptides; Signal Transduction; Stomach Neoplasms; Sulfides

We have investigated the effects of glycyrrhizin (GL) on cell proliferations of human stomach cancer KATO III and promyelotic leukemia HL-60 cells, and on DNA of those cell lines. GL displayed growth inhibitory effect against KATO III and HL-60 cells. Morphological change showing apoptotic bodies was observed in the KATO III and HL-60 cells treated with GL. The fragmentation of DNA by GL to oligonucleosomal-sized fragments that is a characteristic of apoptosis was observed to be concentration- and time-dependent in both cell lines. Caspase inhibitors such as Z-VAD-FMK and Z-Asp-CH2-DCB suppressed the DNA fragmentation induced by GL. The data of the present study show that the suppression of KATO III and HL-60 cell-growth by GL results from the induction of apoptosis by GL, and that caspase is involved in the induction of apoptosis by GL in these cells.

Topics: Amino Acid Chloromethyl Ketones; Apoptosis; Aspartic Acid; Caspase Inhibitors; Cell Line, Tumor; Cysteine Proteinase Inhibitors; DNA Fragmentation; Dose-Response Relationship, Drug; Glycyrrhizic Acid; HL-60 Cells; Humans; Leukemia, Promyelocytic, Acute; Oligopeptides; Stomach Neoplasms; Time Factors

To evaluate the therapeutic effectiveness of oxaliplatin on human gastric carcinoma and to explore its mechanisms.. Twenty-two cases of stage IV gastric carcinoma received 4-6 (mean 4.6) cycles of first line combined chemotherapy with oxaliplatin (oxaliplatin 85 mg/m(2), iv, gtt, 1 h, d 1; leukovorin 200 mg/m(2), iv, gtt, 1 h, d 1 and d 2; 5-FU 300 mg/m(2),iv, d 1 and d 2, 5-FU, continuous iv, gtt, 48 h; 1 cycle/2 wk). Response rate, progression-free survival (PFS), total survival time, toxic side effects were evaluated. The inhibitory effect of oxaliplatin on human gastric cell line SGC-7901 was detected and IC(50) was calculated by MTT. Transmission electron microscopy, flow cytometry and TUNEL were performed to evaluate the apoptosis of cell line induced by the drug. The expression of Caspase-3 m-RNA was detected by RT-PCR. AC-DEVD-CHO, a Caspase-3 specific inhibitor, was used to elucidate the role of activated Caspase-3 in the process of apoptosis induced by oxaliplatin.. Total response (complete and partial) occurred in 9 (40.9%) patients. Mean PFS was 4.2 mo and mean total survival time was 7.2 mo. Cumulative neurotoxicity (all grade I-II), vomiting and diarrhea, myelosuppression appeared in 93.5%, 20%, 32.9% patients, respectively. IC(50) was calculated to be 0.71 mg/L by MTT assay. A maximal inhibitory rate reached 85.3%. Apoptosis index was elevated after incubated with 1 mmol/L oxaliplatin for 30 min, but without statistic significance (P>0.05). However it could be detected at a much higher degree both by flowcytometry and by TUNEL with a statistical significance (68.47+/-7.92% and 8.23+/-2.67%, respectively, P<0.05) after incubated with 1 mmol/L oxaliplatin for 2 d. By means of RT-PCR, we detected an enhancement of Caspase-3 m-RNA expression induced by oxaliplatin which was also in positive correlation with the apoptotic level. AC-DEVD-CHO, a Caspase-3 specific inhibitor, could significantly inhibit and delay apoptosis induced by oxaliplatin.. Oxaliplatin is effective and well-tolerated in patients with advanced gastric carcinoma. Oxaliplatin could significantly inhibit the growth of human gastric cell line SGC-7901. The induction of Caspase-3 m-RNA expression, activation of Caspase-3 and promotion of apoptosis may be some of the therapeutic mechanisms of oxaliplatin on gastric carcinoma. Annexin-V-fluorescein labeling flow cytometry is much more sensitive than TUNEL in detecting early stage apoptosis.

Topics: Adult; Aged; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cysteine Proteinase Inhibitors; Female; Humans; Male; Middle Aged; Neoplasm Staging; Oligopeptides; Organoplatinum Compounds; Oxaliplatin; Stomach Neoplasms