JTE-522-induced apoptosis in human gastric adenocarinoma cell line AGS cells by caspase activation accompanying cytochrome C release, membrane translocation of Bax and loss of mitochondrial membrane potential

Nano - drug Delivery of Apoptosis Activator 2 to AGS Cells by Liposomes Conjugated with Anti-TROP2 Antibody

Background:

Gastric cancer is the second most common causes of cancer related death in the world and is responsible for two third of cancer related death in the developing countries. survival rate surgery is low and radiation therapy and chemotherapy as alternatives ways for treatment of gastric cancer are not very promising. Thus there is an urgent need for introducing novel treatment procedures and promising new anti-canceric drugs.

Aim:

In this study we used pre-prepared liposomes and after necessary manipulations ,these modified liposomes were used for delivery of apoptosis activator 2 to gastric adenocarcinoma cell line (AGS).

Materials and Methods:

we used pre-prepared liposomes and after necessary manipulations, these modified liposomes were used for delivery of apoptosis activator 2 to AGS cells and induced apoptosis was evaluated by related apoptotic DNA ladder, TUNNEL and Cell Death experiments.

Results:

Evaluation of apoptosis by Apoptotic DNA Ladder in liposome treated and untreated AGS cells by DNA laddering and fragmentation, TUNEL and Cell Death Detection confirmed that treatment of AGS cell lines with apoptosis activator 2 loaded liposomes which targeted cell surface TROP2 antigen in cancer cells significantly increased apoptosis in these cells.

Conclusion:

Nano drug delivery of apoptosis activator 2 to human gastric adenocarcinoma cell line with liposomes targeted TROP2 antigen is a possible way for smart killing of human gastric adenocarcinoma cells.

Exogenous phosphatidylethanolamine induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway

AIM: To investigate the signaling pathways implicated in phosphatidylethanolamine (PE)-induced apoptosis of human hepatoma HepG2 cells.

METHODS: Inhibitory effects of PE on human hepatoma HepG2 cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle, apoptosis and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry. Immunocytochemical assay and Western blotting were used to examine Bcl-2, Bax and caspase-3 protein levels in HepG2 cells treated with PE.

RESULTS: PE inhibited the growth of HepG2 cells in a dose- and time- dependent manner. It did not affect the cell cycle, but induced apoptosis. PE significantly decreased δΨm at 0.25, 0.5 and 1 mmol/L, respectively, suggesting that PE induces cell apoptosis by decreasing the mitochondrial transmembrane potential. The Bcl-2 expression level induced by different concentrations of PE was lower than that in control groups. However, the Bax expression level induced by PE was higher than that in the control group. Meanwhile, PE increased the caspase-3 expression in a dose- and time-dependent manner.

CONCLUSION: Exogenous PE induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway.

Clinical efficacy and mechanism of oxaliplatin in treating human gastric carcinoma

AIM

To evaluate the therapeutic effect of oxaliplatin on human gastric carcinoma and to explore the mechanisms.

METHODS

22 cases of stage IV gastric carcinoma patients received 4-6 (mean 4.6) cycles of first line combined chemotherapy with oxaliplatin (oxaliplatin 85 mg/m², ivgtt, 1 h, d 1; leukovorin 200 mg/m², iv, gtt, 1 h, d 1-5; 5-FU 300 mg/m², iv, d 1-2; 5-FU, continuously iv, gtt, 48 h; 1 cycle/2w). 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 calculated by MTT and IC50 was measured. Flow cytometry and TUNEL were applied to evaluate the apoptosis of cell line induced by the drug. The expression of caspase-3 mRNA was detected by RT-PCR.

RESULTS

Total response (complete and partial) occurred in 9 (40.9%) patients. Mean PFS was 4.2 months and mean total survival time was 7.2 months. Cumulative neurotoxicity (all grade I-II), vomiting and diarrhea, myelosuppression appeared in 93.5%, 20%, 32.9% of the patients, respectively. Apoptosis index was elevated after incubating with 1 mmol/L oxaliplatin for 30 min, but without statistic significance (P>0.05), but was much higher both by flowcytometry and TUNEL with statistical significance (P<0.05) after incubating with 1 mmol/L oxaliplatin for 2 days. Caspase-3 mRNA expression was elevated in oxaliplatin treated cells and correlated with apoptosis induced by the drug.

CONCLUSION

Oxaliplatin is effective and well-tolerated on human advanced gastric carcinoma. Oxaliplatin could significantly inhibit the growth of human gastric cell line SGC-7901, inducing caspase-3 mRNA expression and cell apoptosis.

Homocysteine induces trophoblast cell death with apoptotic features

Hyperhomocysteinemia has been suggested as a possible risk factor in women suffering from habitual abortions, placental abruption or infarcts, preeclampsia, and/or intrauterine growth retardation. However, little is known about the pathogenic mechanisms underlying the action of homocysteine. The present study investigated the in vitro ability of homocysteine to affect trophoblast gonadotropin secretion and to induce cell death. In primary human trophoblast cells, homocysteine treatment (20 micromol/L) resulted in cellular flattening and enlargement, extension of pseudopodia, and cellular vacuolization. Cellular detachment, apoptosis, and necrosis were favored. With in situ nick end labeling, we investigated DNA degradation, and we used M30 CytoDEATH to selectively stain the cytoplasm of apoptotic cells. Cytochrome c release from mitochondria to the cytosol and DNA cleavage in agarose gel have been investigated. Homocysteine, but not cysteine, induced trophoblast apoptosis and significantly reduced human chorionic gonadotropin secretion. These findings suggest that trophoblast cell death might represent a pathogenic mechanism by which homocysteine may cause pregnancy complications related to placental diseases.

Peroxisome proliferator-activated receptor gamma ligands inhibit cell growth and induce apoptosis in human liver cancer BEL-7402 cells

AIM: To investigate the characteristics of PPAR gamma ligands induced apoptosis in liver cancer cells.

METHODS: The effects of ligands for each of the PPAR gamma ligands on DNA synthesis and cell viability were examined in BEL-7402 liver cancer cells. Apoptosis was characterized by Hochest33258 staining, DNA fragmentation, TUNEL and ELISA, and cell cycle kinetics by FACS. Modulation of apoptosis related caspases expression by PPAR gamma ligands was examined by Western blot.

RESULTS: PPARgamma ligands, 15-deoxy-^{12, 14}-prostaglandin J2 (15d-PGJ2) and troglitazone (TGZ), suppressed DNA synthesis of BEL-7402 cells. Both 15d-PGJ2 and TGZ induced BEL-7402 cell death in a dose dependent manner, which was associated with an increase in fragmented DNA and TUNEL-positive cells. At concentrations of 10 and 30 µM, 15d-PGJ₂ or troglitazone increased the proportion of cells with G₀/G₁ phase DNA content and decreased those with S phase DNA content. There was no significant change in the proportion of cells with G₂/M DNA content. The activities of Caspases-3, -6, -7 and -9 were increased by 15d-PGJ2 and TGZ treatment, while the activity of Caspase 8 had not significantly changed.

CONCLUSION: The present results suggest the potential usefulness of PPAR gamma ligands for chemoprevention and treatment of liver cancers.

PPARγ pathway activation results in apoptosis and COX-2 inhibition in HepG2 cells

AIM: To investigate whether troglitazone (TGZ), the peroxisome proliferator-activated receptor (PPAR) gamma ligand, can induce apoptosis and inhibit cell proliferation in human liver cancer cell line HepG2 and to explore the molecular mechanisms.

METHODS: [3-(4, 5)-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT), [³H] Thymidine incorporation, Hochest33258 staining, DNA ladder, enzyme-linked immunosorbent assay (ELISA), RT-PCR, Northern and Western blotting analyses were employed to investigate the effect of TGZ on HepG2 cells and related molecular mechanisms.

RESULTS: TGZ was found to inhibit the growth of HepG2 cells and to induce apoptosis. During the process, the expression of COX-2 mRNA and protein and Bcl-2 protein was down-regulated, while that of Bax and Bak proteins was up-regulated, and the activity of caspase-3 was elevated. Furthermore, the level of PGE₂ was decreased transiently after 12 h of treatment with 30 μM troglitazone.

CONCLUSION: TGZ inhibits cell proliferation and induces apoptosis in HepG2 cells, which may be associated with the activation of caspase-3-like proteases, down-regulation of the expression of COX-2 mRNA and protein, Bcl-2 protein, the elevation of PGE₂ levels, and up-regulation of the expressions of Bax and Bak proteins.

Synergistic effects of nimesulide and 5-fluorouracil on tumor growth and apoptosis in the implanted hepatoma in mice

AIM: To compare the effect of nimesulide or/and 5-fluorouracil (5-FU) on tumor growth inhibition and apoptosis in mice with the implanted hepatoma and to observe their possible interactions.

METHODS: The inhibitory effects on tumor growth was evaluated by inhibition rate. Apoptosis was assessed by the ultrastructural, flow cytometry features and the DNA ladder demonstrated by agarose gel electrophoresis. PGE₂ level was determined by radioimmunoassay. Expression levels of c-jun, c-fos and p53 were evaluated by western blotting.

RESULTS: Nimesulide or 5-FU alone inhibited the growth of hepatoma, while a synergistic effect was observed for a combined use of both. More pronounced morphologic changes for tumor cell apoptosis and the DNA ladder were found for the latter treatment. Expression levels of c-jun and p53 were found to be elevated for the tumors from mice treated with nimesulide and 5-FU comparing to those with either of them, but a reduced PGE₂ level was observed only for the treatment with nimesulide. No change was detected on c-fos expression.

CONCLUSION: Nimesulide and 5-FU appear to have synergistic effects for the growth inhibition and apoptosis induction. Both were found to be overexpressed in p53 and c-jun proteins, rather than that of c-fos, associations with the resulted apoptosis.

Tributyrin inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM

To evaluate the effects of tributyrin, a pro-drug of natural butyrate and a neutral short-chain fatty acid triglyceride, on the growth inhibition of human gastric cancer SGC-7901 cell.

METHODS

Human gastric cancer SGC-7901 cells were exposed to tributyrin at 0.5, 1, 2, 5, 10 and 50 mmol/L(-1) for 24-72 h. MTT assay was applied to detect the cell proliferation. [(3)H]-TdR uptake was measured to determine DNA synthesis. Apoptotic morphology was observed by electron microscopy and Hoechst-33258 staining. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed to detect tributyrin-triggered apoptosis. The expressions of PARP, Bcl-2 and Bax were examined by Western blot assay.

RESULTS

Tributyrin could initiate growth inhibition of SGC-7901 cell in a dose- and time-dependent manner. [(3)H]-TdR uptake by SGC-7901 cells was reduced to 33.6 % after 48 h treatment with 2 mmol/L(-1) tributyrin, compared with the control (P<0.05). Apoptotic morphology was detected by TUNEL assay. Flow cytometry revealed that tributyrin could induce apoptosis of SGC-7901 cells in dose-dependent manner. After 48 hours incubation with tributyrin at 2 mmol/L(-1), the level of Bcl-2 protein was lowered, and the level of Bax protein was increased in SGC-7901, accompanied by PARP cleavage.

CONCLUSION

Tributyrin could inhibit the growth of gastric cancer cells effectively in vitro by inhibiting DNA synthesis and inducing apoptosis, which was associated with the down-regulated Bcl-2 expression and the up-regulated Bax expression. Therefore, tributyrin might be a promising chemopreventive and chemotherapeutic agent against human gastric carcinogenesis.

Roles of Fas signaling pathway in vitamin E succinate-induced apoptosis in human gastric cancer SGC-7901 cells

AIM

To investigate the roles of Fas signaling pathway in vitamin E succinate-induced apoptosis in human gastric cancer SGC-7901 cells.

METHODS

Human gastric cancer SGC-7901 cells were treated with VES at 5, 10, 20 mg x L(-1), succinic acid and vitamin E as vehicle control and condition media only as untreated (UT) control. Apoptotic morphology was observed by DAPI staining. Western blot analysis was applied to measure the expression of Fas, FADD and caspase-8 proteins. After the cells were transiently transfected with Fas and FADD antisense oligonucleotides, respectively, caspase-8 activity was determined by flurometric method.

RESULTS

The morphologically apoptotic changes were observed after VES treatment by DAPI staining. 23.7 % and 89.6 % apoptosis occurred after 24 h and 48 h of 20 mg x L(-1) VES treatment, respectively. The protein levels of Fas, FADD and caspase-8 were evidently increased in a dose-dependent manner after 24 h of VES treatment. The blockage of Fas by transfection with Fas antisense oligonucleotides obviously inhibited the expression of FADD protein. After SGC-7901 cells were transfected with Fas and FADD antisense oligonucleotides, caspase-8 activity was obviously decreased (P<0.01), whereas Fas blocked more than FADD.

CONCLUSION

VES-induced apoptosis in human gastric cancer SGC-7901 cells involves Fas signaling pathway including the interaction of Fas, FADD and caspase-8.