Effect of gamma-aminobutyric acid on the growth of pancreatic cancer cell line SW1990

AIM: To investigate the effect of gamma-aminobutyric acid (GABA) on the growth of pancreatic cancer cell line SW1990.

METHODS: Pancreatic cancer cell line SW1990 was cultured by routine method, and then treated with different concentrations of GABA (20-320 μmol/L). The proliferation, apoptosis, and cell cycle of SW1990 cells was investigated by MTT assay and flow cytometry, respectively. Radioimmunoassay was used to measure the intracellular cyclic adenosine monophosphate (cAMP) content.

RESULTS: The different concentrations of GABA promoted the growth of SW1990 cells and affected the distribution of cell cycle. The percentage of cells in G₀/G₁ phase was decreased while that in S and G₂/M phase was increased. The content of intracellular cAMP was increased with the increase of GABA concentration in a dose-dependent manner (P < 0.01). The apoptosis rate of SW1990 cells was decreased from 27.5% to 5.4%, which had significant difference (χ² = 10.19, P <0.01).

CONCLUSION: GABA can promote the proliferation of SW1990 cells by inhibiting apoptosis and influencing the distribution of cell cycle, which may be mediated by the information transition of post-receptor.

Differential effects on apoptosis induction in hepatocyte lines by stable expression of hepatitis B virus X protein

AIM: Hepatitis B virus protein X (HBx) has been shown to be weakly oncogenic in vitro. The transforming activities of HBx have been linked with the inhibition of several functions of the tumor suppressor p53. We have studied whether HBx may have different effects on p53 depending on the cell type.

METHODS: We used the human hepatoma cell line HepG2 and the immortalized murine hepatocyte line AML12 and analyzed stably transfected clones which expressed physiological amounts of HBx. P53 was induced by UV irradiation.

RESULTS: The p53 induction by UV irradiation was unaffected by stable expression of HBx. However, the expression of the cyclin kinase inhibitor p21^waf/cip/sdi which gets activated by p53 was affected in the HBx transformed cell line AML12-HBx9, but not in HepG2. In AML-HBx9 cells, p21^waf/cip/sdi-protein expression and p21^waf/cip/sdi transcription were deregulated. Furthermore, the process of apoptosis was affected in opposite ways in the two cell lines investigated. While stable expression of HBx enhanced apoptosis induced by UV irradiation in HepG2-cells, apoptosis was decreased in HBx transformed AML12-HBx9. P53 repressed transcription from the HBV enhancer I, when expressed from expression vectors or after induction of endogenous p53 by UV irradiation. Repression by endogenous p53 was partially reversible by stably expressed HBx in both cell lines.

CONCLUSION: Stable expression of HBx leads to deregulation of apoptosis induced by UV irradiation depending on the cell line used. In an immortalized hepatocyte line HBx acted anti-apoptotic whereas expression in a carcinoma derived hepatocyte line HBx enhanced apoptosis.

H pylori receptor MHC class II contributes to the dynamic gastric epithelial apoptotic response

AIM: To investigate the role of MHC class II in the modulation of gastric epithelial cell apoptosis induced by H pylori infection.

METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonist antibodies specific for MHC class II and CD95, the quantitation of apoptotic and anti-apoptotic events, including caspase activation, BCL-2 activation, and FADD recruitment, was performed with a fluorometric assay, a cytometric bead array, and confocal microscopy, respectively.

RESULTS: Pretreatment of N87 cells with the anti-MHC class II IgM antibody RFD1 resulted in a reduction in global caspase activation at 24 h of H pylori infection. When caspase 3 activation was specifically measured, crosslinking of MHC class II resulted in markedly reduced caspase activation, while simple ligation of MHC class II did not. Crosslinking of MHC class II also resulted in an increased activation of the anti-apoptosis molecule BCL-2 compared to simple ligation. Confocal microscope analysis demonstrated that the pretreatment of gastric epithelial cells with a crosslinking anti-MHC class II IgM blocked the recruitment of FADD to the cell surface.

CONCLUSION: The ability of MHC class II to modulate gastric epithelial apoptosis is at least partially dependent on its crosslinking. The crosslinking of this molecule has anti-apoptotic effects during the earlier time points of H pylori infection. This effect is possibly mediated by the ability of MHC class II to modulate the activation of the pro-apoptotic receptor Fas by blocking the recruitment of the accessory molecule FADD, and this delay in apoptosis induction could allow for prolonged cytokine secretion by H pylori-infected gastric epithelial cells.

Hot water-extracted Lycium barbarum and Rehmannia glutinosa inhibit proliferation and induce apoptosis of hepatocellular carcinoma cells

AIM: To investigate the effect of hot water-extracted Lycium barbarum (LBE) and Rehmannia glutinosa (RGE) on cell proliferation and apoptosis in rat and/or human hepatocellular carcinoma (HCC) cells.

METHODS: Rat (H-4-II-E) and human HCC (HA22T/VGH) cell lines were incubated with various concentrations (0-10 g/L) of hot water-extracted LBE and RGE. After 6-24 h incubation, cell proliferation (n = 6) was measured by a colorimetric method. The apoptotic cells (n = 6) were detected by flow cytometry. The expression of p53 protein (n = 3) was determined by SDS-PAGE and Western blotting.

RESULTS: Crude LBE (2-5 g/L) and RGE (2-10 g/L) dose-dependently inhibited proliferation of H-4-II-E cells by 11% (P < 0.05) to 85% (P < 0.01) after 6-24 h treatment. Crude LBE at a dose of 5 g/L suppressed cell proliferation of H-4-II-E cells more effectively than crude RGE after 6-24 h incubation (P < 0.01). Crude LBE (2-10 g/L) and RGE (2-5 g/L) also dose-dependently inhibited proliferation of HA22T/VGH cells by 14%-43% (P < 0.01) after 24 h. Crude LBE at a dose of 10 g/L inhibited the proliferation of HA22T/VGH cells more effectively than crude RGE (56.8% ± 1.6% vs 70.3% ± 3.1% of control, P = 0.0003 < 0.01). The apoptotic cells significantly increased in H-4-II-E cells after 24 h treatment with higher doses of crude LBE (2-5 g/L) and RGE (5-10 g/L) (P < 0.01). The expression of p53 protein in H-4-II-E cells was 119% and 143% of the control group compared with the LBE-treated (2, 5 g/L) groups, and 110% and 132% of the control group compared with the RGE -treated (5, 10 g/L) groups after 24 h.

CONCLUSION: Hot water-extracted crude LBE (2-5 g/L) and RGE (5-10 g/L) inhibit proliferation and stimulate p53-mediated apoptosis in HCC cells.

Interleukin-24 selectively induces growth suppression and apoptosis in human gastric cancer cells transfected with a single tetracycline-regulatable plasmid

AIM: To estimate the tumor-suppressive activity of interleukin-24 (IL-24) in gastric cancer cells in vitro and the regulation of tetracycline in a single plasmid pCEP4-tetR-IL-24.

METHODS: A single plasmid pCEP4-tetR-IL-24 was constructed which contained the TetR and TetO. The cells were transfected with pCEP4-tetR-IL-24 using lipofectamine 2000. The expression of IL-24 was detected by Western blotting. The suppression of cellular growth was determined by MTT assay and trypan blue rejection. The induction of apoptosis was analyzed by Annexin Ⅴ staining.

RESULTS: IL-24 protein was induced to express in gastric cancer cells (MGC803 and BGC823) and normal cells (GES-1) after transfection with pCEP4-tetR-IL-24. In the MGC803 and BGC823 cells, cellular growth was inhibited more efficiently (P < 0.01, 0.001-0.006), and the percentage of apoptosis cells was higher after doxycline induction (23.5%/25.6%→33.8%/36.7%, P < 0.01). However, there were no differences observed in GES-1 cells among the groups (P > 0.05).

CONCLUSION: The plasmid-mediated tranfection of IL-24 selectively induces the suppression of cell growth and apoptosis in gastric cancer cells. Tetracycline can regulate the expression of IL-24 in gastric cancer cells and normal epithelial cells.

IGrowth inhibition of human hepatocarcinoma cells induced by Chinese herbs Huqi San and its principal drug mistletoe extracts

AIM: To probe the effect of Chinese herbs, Huqi San (HQS) and its principal drug mistletoe extracts on the growth of human hepatocar-cinoma cell line SMMC-7721 and the levels of intracellular reactive oxygen species (ROS).

METHODS: The proliferation of SMMC-7721 cells inhibited by HQS (0.3125, 0.625, 1.25 g/L), mistletoe polysaccharides (0.625, 1.25, 2.5, 5 g/L) and total alkaloid of mistletoe (3, 6, 12 g/L) at 48, 72 and 96 h were observed by MTT assay. The cell cycle and apoptosis rate of SMMC-7721 cells were examined by flow cytometry. The fluorescent intensity of ROS was observed by laser scanning confocal microscopy.

RESULTS: Both HQS and mistletoe extracts inhibited the proliferation of SMMC-7721 cells in a time- and dose-dependence manner, and the numeric value of absorbance in high-dose group decreased markedly as compared with that in the control group (HQS 72 h: 1.022 ± 0.13 vs 1.207 ± 0.04, P < 0.01; 96 h: 1.235 ± 0.20 vs 1.602 ± 0.05, P < 0.01; mistletoe polysaccharides 48 h: 0.570 ± 0.03 vs 0.744 ± 0.01, P < 0.01; 72 h: 0.803 ± 0.04 vs 1.207 ± 0.04, P < 0.01; 96 h: 0.860 ± 0.13 vs 1.602 ± 0.05, P < 0.01; total alkaloid of mistletoe 72 h: 0.919 ± 0.14 vs 1.233 ± 0.04, P < 0.01; 96 h: 0.701 ± 0.07 vs 1.819 ± 0.04, P < 0.01), expect that at 48 h in HQS and total alkaloid of mistletoe group. After treatment with the drugs for 72 h, the cell populations in the group of mistletoe polysaccharides and total alkaloid of mistletoe increased in G1 phase (81.0%, 86.9% vs 70.0%, P < 0.01) and decreased in G2 and S phase (13.1%, 5.7% vs 16.4%, P < 0.01; 5.9%, 7.4% vs 13.5%, P < 0.01), in comparison with those in the controls. In the group of HQS, the proportion of S-phase cells decreased (1.5% vs 13.5%, P < 0.01) while that of G2-phase ones increased (28.2% vs 16.4%, P < 0.01). However, there was no obvious change in the numbers of G1-phase cells. In addition, all of the three drugs enhanced the apoptosis of SMMC-7721 cells (HQS: 14.8% vs 6.0%, P < 0.01; mistletoe polysaccharides: 11.7% vs 6.0%, P < 0.01; total alkaloid of mistletoe: 6.7% vs 6.0%, P < 0.05). Confocal microscopy showed that the fluorescent intensity declined suddenly and then maintained at a low level almost without fluctuating when the three kinds of drugs were added. However, after the fluorescent intensity was stabile at a baseline, it increased instantly as the total alkaloid of mistletoe was added. Thereafter, it decreased rapidly and maintained at a low level for a period of time. But this phenomenon was not observed when the cells were treated with HQS and mistletoe polysaccharides.

CONCLUSION: HQS, mistletoe polysaccharides and total alkaloid of mistletoe can inhibit the proliferation and promote the apoptosis of SMMC-7721 cells.

Immuno-protective effect of liver on small bowel in combined transplantation of liver and small bowel

AIM: To develop a new combined transplan-tation model of liver and small bowel in rats, and to investigate the protective effect of trans-planted liver on transplanted small bowel.

METHODS: Closed colony Sprague Dawley rats and inbred Wistar rats were included in this study. Five groups were designed: isogene small bowel transplant group (A), isogene liver transplant group (B), xenogene small bowel transplant group (C), xenogene liver transplant group (D), combined transplant of liver and small bowel group (E). Only Wistar rats were used in group A and B, while SD and Wistar rats were used as donors and recipients respectively in group C, D and E. During the combined transplantation of liver and small bowel (CTLS) for the donors, inferior vena cava in chest was cut to construct a muff in the lateral wall of portal vein and cuff was placed. During the operation for the recipients, portal veins of the donors and recipients were connected using cuff technique, and re-arterialization was completed by anastomosing the superior mesenteric artery of graft with the right kidney artery of the recipients. Randomly selected 4 rats from each group were sacrificed on postoperative days (POD) 5, 7 and 14, and grafts were sampled. The rejection of graft was investigated through histopathological analysis, and the apoptosis of the cells of graft were evaluated by TUNEL.

RESULTS: The survival rate of CTLS was 73.3% (22/30). The pathological changes of ischemia and reperfusion injury were observed in group A and B, and the numbers of apoptotic cells in the grafts were decreased with the prolonging of time. However, acute rejection after transplantation appeared in group C and D, and there were more apoptotic cells in the grafts. Mild, moderate and severe acute rejection occurred on POD 5, 7 and 14, respectively in group C, while only mild or severe acute rejection appeared in group E. Furthermore, the number of apoptotic cells in the grafts of group E was markedly decreased on POD 14 in comparison with that of group C (16.9 ± 4.3 vs 20.5 ± 6.3, P < 0.05). The degrees of acute rejection after transplantation and cell apoptosis of the grafts were not significantly different between group D and E.

CONCLUSION: The technique used in this study is feasible for establishment of CTLS model, and the transplanted liver can protect the transplanted intestinal graft from rejection in CTLS.

Cell cycle regulatory protein expression profiles by adenovirus p53 infection in human papilloma virus-associated cervical cancer cells

PURPOSE

The tumor suppressor gene, p53, has been established as an essential component for the suppression of tumor cell growth. In this study, we investigated the time-course anticancer effects of adenoviral p53 (Adp53) infection on human ovarian cancer cells to provide insight into the molecular-level understanding of the growth suppression mechanisms involved in Adp53-mediated apoptosis and cell cycle arrest.

MATERIALS AND METHODS

Three human cervical cancer cell lines (SiHa, CaSki, HeLa and HT3) were used. The effect of Adp53 infection was studied via cell count assay, cell cycle analysis, FACS, Western blot and macroarray assay.

RESULTS

Adp53 exerts a significant role in suppressing cervical cancer cell growth. Adp53 also showed growth inhibitory effects in each cell line, and it induced apoptosis and cell cycle arrest. Adp53 differentially regulated the expression of genes and proteins, and the gene expression profiles in the SiHa cells revealed that the p21, p53 and mdm2 expressions were significantly up-regulated at 24 and 48 hr. Western blot shows that the p21 and p53 expression-levels were significantly increased after Adp53 infection. In addition, in all cell lines, both the CDK4 and PCNA protein expression levels were decreased 48 h after Adp53 infection. Cell cycle arrest at the G1 phase was induced only in the SiHa and HeLa cells, suggesting that exogenous infection of Adp53 in cancer cells was significantly different from the other HPV-associated cervical cancer cells.

CONCLUSION

Adp53 can inhibit cervical cancer cell growth through induction of apoptosis and cell cycle arrest, as well as through the regulation of the cell cycle-related proteins. The Adp53-mediated apoptosis can be employed as an advanced strategy for developing preferential tumor cell-specific delivery.

Apoptosis of human colon carcinoma HT-29 cells induced by ceramide

AIM: To investigate the effect of exogenous ceramide-induced apoptosis on human colon carcinoma HT-29 cells.

METHODS: Light microscope, transmission electron microscope and fluorescence microscope were used to observe the morphology change of apoptosis in HT-29 cells. Agarose gel electrophoresis was performed to detect the DNA fragment. Mitochondrial function was detected by MTT assay. mRNA expression of Bcl-2 family gene members was determined by reverse transcription polymerase chain reaction (RT-PCR) assay.

RESULTS: After C₂-ceramide treatment, typical characteristics of apoptosis, such as nuclear chromatin breakage, apoptotic body and DNA ladder, could be observed. After exposure to 50 μmol/L C₂-ceramide for 12 and 24 h, cell apoptosis was 64.1% and 81.3% respectively, which had a time-and dose-effect relationship. Mitochondrial function started to decrease from 6 h after exposure to ceramide. Meanwhile, ceramide up-regulated or down-regulated the mRNA expression of Bcl-2 family gene members.

CONCLUSION: Ceramide induces apoptosis of human colon carcinoma HT-29 cells by affecting the expression of Bcl-2 family gene members and impacting the mitochondrial function.

Calcium signaling in cholangiocytes

Cytosolic Ca²⁺ is an important second messenger in virtually every type of cell. Moreover, Ca²⁺ generally regulates multiple activities within individual cells. This article reviews the cellular machinery that is responsible for Ca²⁺ signaling in cholangiocytes. In addition, two Ca²⁺-mediated events in cholangiocytes are discussed: bicarbonate secretion and apoptosis. Finally, emerging evidence is reviewed that Ca²⁺ signaling is involved in the pathogenesis of diseases affecting the biliary tree and that Ca²⁺ signaling pathways can be manipulated to therapeutic advantage in the treatment of cholestatic disorders.

Effect of tanshinone II A on COX-2 expression in hepatocellular carcinoma cell line SMMC-7721

AIM: To observe the effect of Tanshinone II A on the proliferation and apoptosis of human hepatocellular carcinoma cell line SMMC-7721 and its machanism.

METHODS: The human hepatocellular carcinoma cell line SMMC-7721 cultured in vitro was treated with different concentrations (final 0.5 mg/L) Tanshinone II A. The proliferation of the cells was measured by MTT assay, and the apoptosis of the cells was investigated by flow cytometry and transmission electron microscopy (TEM). The expression of Cyclooxygenase-2 (COX-2) was detected by immunocytochemistry. The levels of prostaglandin E2 (PGE2) in medium were measured by radioimmunoassay.

RESULTS: Tanshinone II A inhibited the growth of SMMC-7721 cells in a dose-dependent manner. The inhibitory rate reached the peak (69.3%) after 0.5 mg/L Tanshinone II A was used for 48 h, which was significantly higher than that in the controls (P < 0.01). Typical features of apoptosis as cell shrinkage, nuclear chromatin condensation, fragmentation, and the formation of apoptotic bodies was found by TEM in the cells treated with Tanshinone II A. FCM analysis showed the apoptotic rates for 24, 48 and 72 h were 7.45% ± 0.33%, 6.59% ± 0.45%, and 4.78% ± 1.05%, respectively, when 5 mg/L Tanshinone II A was used, which were markedly higher than those in the controls (all P < 0.01). Both the expression of COX-2 (P < 0.01) and the production of PGE2 (40.18 ± 1.37 μg/L vs 75.31 ± 1.64 μg/L, P < 0.01) were decreased significantly after Tanshinone II A treatment as compared with those in the controls.

CONCLUSION: Tanshinone II A inhibits the proliferation and increases the apoptosis of human hepatocellular carcinoma cell line SMMC-7721 by down-regulation of COX-2 protein expression.

Partial Beclin 1 silencing aggravates doxorubicin- and Fas-induced apoptosis in HepG2 cells

AIM: To investigate the role of Beclin 1 on the susceptibility of HepG2 cells to undergo apoptosis after anti-Fas antibody or doxorubicin treatment.

METHODS: Beclin 1 silencing was achieved using RNA interference. DNA ploidy, the percentage of apoptotic cells and the mitochondrial membrane potential were assessed by flow cytometry. Levels of Beclin 1, Bcl-X_L and cytochrome c, and the cleavage of poly (ADP-ribose) polymerase (PARP) were assayed by using Western blots.

RESULTS: Beclin 1 expression decreased by 75% 72 h after Beclin 1 siRNA transfection. Partial Beclin 1 silencing significantly increased the percentage of subG1 cells 24 and 40 h after treatment with doxorubicin or anti-Fas antibody, respectively, and this potentiation was abrogated by treatment with a pan-caspase inhibitor. Partial Beclin 1 silencing also increased PARP cleavage, mitochondrial membrane depolarization and cytosolic cytochrome c. The pro-apoptotic consequences of partial Beclin 1 silencing were not associated with a decline in Bcl-X_L expression.

CONCLUSION: Partial Beclin 1 silencing aggravates mitochondrial permeabilization and apoptosis in HepG2 cells treated with an anti-Fas antibody or with doxorubicin.

Synergistic inhibitory effect of NS-398 combined with AG-041R on gastric cancer cells

AIM: To investigate the inhibitory effects and mechanisms of combined treatment of a special COX-2 inhibitor (NS-398) and a special gastric receptor antagonist (AG-041R) on gastric cancer cell line MKN-45.

METHODS: The human gastric cancer cell line MKN-45 was treated with NS398 and AG-041R, respectively, or in combination. The growth of MKN-45 cells was detected by MTT assay; the cell apoptosis was detected by flow cytometry; the expression of c-Myc mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS: NS-398 and AG-041R inhibited the growth of MKN-45 cells in a time- and dose-dependent manner (12-72 h; NS-398: 1 × 10^-8 - 1 × 10^-4 mol/L; AG-041R: 1 × 10^-8 - 1 × 10^-5 mol/L). AG-041R (1×10^-6 mol/L) and NS-398 (1×10^-5 mol/L) inhibited the proliferation of MKN-45 cells at rates of 42.1% and 41.8%, respectively, at 72 h. NS-398 and AG-041R in combination resulted in a synergistic effect on inhibiting growth, and the inhibition effect was enhanced along with time. When NS-398 (1×10^-5 mol/L) or AG-041R (1×10^-6 mol/L) or their combination was used, the rate of apoptosis was 9.57% ± 0.60%, 10.25% ± 0.68% and 20.83% ± 1.90%, respectively, which was significantly higher than the rate in the controls (1.67% ± 0.76%)(all P < 0.01), and the agents in combination induced a higher apoptosis rate than either of them did (P < 0.01). NS-398 and AG-041R down-regulated the level of c-Myc mRNA, respectively, but their combination down-regulated it more significantly than either of the agents did.

CONCLUSION: Combined treatment of NS-398 and AG-041R synergistically inhibits the growth of MKN-45 cells in a time- and dose-dependent manner, induces the cell apoptosis and down-regulates c-Myc mRNA expression in MKN-45 cells.

Effects of Stat5 antisense oligonucleotide combined with 5-fluorouracil on proliferation and apoptosis of gastric cancer cells

AIM: To investigate the mechanism of Stat5 antisense oligonucleotide (Stat5 AS-ON) combined with 5-fluorouracil (5-FU) in the treatment of gastric cancer.

METHODS: Human gastric cancer cell line BGC823 was treated with Stat5 AS-ON and 5-FU, respectively, or in combination. The expression of Stat5, p-Stat5, cyclin D1 and Bcl-xL in the cells were detected by Western blot, and the cell cycle and apoptosis were detected by flow cytometry.

RESULTS: After treatment with Stat5 AS-ON and 5-FU for 72 h, the ratio of G₁-phase cells was up-regulated from 65.7% to 78.2%, and that of S-phase cells was down-regulated from 18.6% to 10.5%; the percentage of apoptotic cells was increased from 7.4% to 21.6%. Stat5 AS-ON and 5-FU synergically inhibited the growth of gastric cancer cells, induced significant apoptosis of the cancer cells, and they reduced the expression and phosphorylation of Stat5, as well as the expression of cyclin D1 and Bcl-xL.

CONCLUSION: Selective inhibition of specific signaling pathway in the cells may provide a new approach in the treatment of gastric cancer.

Augmentation of sodium butyrate-induced apoptosis by phosphatidylinositol 3-kinase inhibition in the human cervical cancer cell-line

PURPOSE

Sodium butyrate (NaBT) is principally a histone deacetylase (HDAC) inhibitor, and it has the potential to arrest HPV-positive carcinoma cells at the G1 to S phase transition of the cell cycle. The aim of study was to determine whether phosphatidylinositol 3-kinase (PI3K) inhibition can enhance the inhibitory effect of NaBT on a human cervical cancer cell line (HeLa).

MATERIALS AND METHODS

Cervical cancer cells (HeLa) were treated with NaBT alone or in combination with the PI3K inhibitors wortmannin or LY294002. Cell viability analysis and FACS analysis were carried out. The expressions of the cell cycle related proteins were evaluated by Western-blot analysis.

RESULTS

Inhibition of PI3K enhanced NaBT-mediated apoptosis and this decreased the HeLa cell viability. Either wortmannin or LY294002, combined with NaBT, enhanced the activation of caspase 3 and caspase 9, and this enhanced the subsequent cleavage of poly (ADP-ribose) polymerase (PARP). Cervical cancer cells were arrested in the subG1 and G2/M phase, as was detected by FACS analysis. NaBT treatment in combination with PI3K inhibitors showed the increased expression of the CDK inhibitors p21(Cip1/Waf1) and p27(Kip1), in a p53 dependent manner, and also the increased dephosphorylation of Rb whereas there was a reduction in the expression levels of cyclin A, cyclin D1 and cyclin B1.

CONCLUSION

The results demonstrate that inhibition of PI3K enhances NaBT-mediated cervical cancer cell apoptosis through the activation of the caspase pathway. Moreover, these findings will support future investigation using the PI3K inhibitors in combination with adjuvant treatment for treating carcinoma of the cervix.

Experimental study on inducing apoptosis and reversing drug resistance of gastric cancer cells SGC7901 by antisense Survivin RNA

AIM: To explore the effect of antisense Survivin RNA on the apoptosis, chemosensitivity to taxotere and drug resistance of gastric cancer cells SGC7901.

METHODS: SGC7901 cells were transfected with antisense Survivin eukaryotic vector (anti-pcDNA3-svv) by lipofectamine, and the positive clones were screened out. Survivin protein and multi-drug resistance-1 (MDR-1) mRNA were determined by Western blot and reverse transcription polymerase chain reaction (RT-PCR). The apoptosis of SGC7901 cells was observed by electronic microscopy and TUNEL method, and the sensitivity of the cells to taxotere was examined by MTT assay.

RESULTS: The expression of Survivin protein in the transfected SGC7901 cells (29% of latter) was decreased obviously in comparison with that in the non-transfected cells (P < 0.01). SGC7901-SVVanti cells (transfected) presented terminal apoptosis, and TUNEL showed that the apoptosis index (AI) was 0.241, which was higher as compared with that of non-transferred cells (0.083) (P < 0.01). MDR-1 index was 0.196 ± 0.013 and 3.126 ± 0.019 in the transfected and non-transfected cells, respectively (P < 0.01). The IC₅₀ of taxotere was 16.7 ± 1.98 and 55.7 ± 1.89 μg/L in the transfected cells and non-transfected ones, respectively (P < 0.01).

CONCLUSION: Antisense Surivivin RNA can induce apoptosis, increase the chemosensitivity to taxotere and reverse the drug resistance of SGC7901 cells.

Recombinant hybrid protein, Shiga toxin and granulocyte macrophage colony stimulating factor effectively induce apoptosis of colon cancer cells

AIM: To investigate the selective cytotoxic effect of constructed hybrid protein on cells expressing granulocyte macrophage colony stimulating factor (GM-CSF) receptor.

METHODS: HepG2 (human hepatoma) and LS174T (colon carcinoma) were used in this study. The fused gene was induced with 0.02 % of arabinose for 4 h and the expressed protein was detected by Western blotting. The chimeric protein expressed in E.coli was checked for its cytotoxic activity on these cells and apoptosis was measured by comet assay and nuclear staining.

RESULTS: The chimeric protein was found to be cytotoxic to the colon cancer cell line expressing GM-CSFRs, but not to HepG2 lacking these receptors. Maximum activity was observed at the concentration of 40 ng/mL after 24 h incubation. The IC₅₀ was 20  ±  3.5 ng/mL.

CONCLUSION: Selective cytotoxic effect of the hybrid protein on the colon cancer cell line expressing GM-CSF receptors (GM-CSFRs) receptor and apoptosis can be observed in this cell line. The hybrid protein can be considered as a therapeutic agent.

Effects of quercetin on proliferation and cell cycle of colon carcinoma cell Line HT-29

AIM: To investigate the effect of quercetin on the proliferation and apoptosis of colon carcinoma cell line HT-29 and its molecular mechanism.

METHODS: HT-29 cells were treated with different concentrations of quercetin (40×10^-6, 80×10^-6 and 160×10^-6 mol/L) for 72 h. HT-29 cells treated with DMSO vehicle were used as the controls. MTT assay, flow cytometry, immunocytochemistry and reverse transcription polymerase chain reaction (RT-PCR) was used to observe the changes of cell proliferation, cell cycle, Caspase-3 protein expression, and bax, bcl-2, and Caspase mRNA expression in HT-29 cells, respectively.

RESULTS: Quercetin at a concentration of 40×10^-6 mol/L promoted the proliferation of HT-29 cells (P < 0.05), while it significantly inhibited the proliferation of HT-29 cells at the concentrations of 80×10^-6 and 160×10^-6 mol/L (P < 0.05 or P < 0.01), showing a time-dependent manner. After treatment with 40×10^-6, 80×10^-6 and 160×10^-6 mol/L quercetin for 72 h, the proliferation ratio of HT-29 cells were 111.8% ± 9.6%, 64.6% ± 8.3% and 26.1% ± 5.7%, respectively; the percentages of HT-29 cells at period G₀/G₁ were 32.7% ± 5.4%, 58.1% ± 18.3% and 71.6% ± 20.8% respectively, and those of HT-29 cells at period S were 48.6% ± 17.5%, 27.4% ± 13.4% and 15.4% ± 10.1%, respectively; the apoptosis rates of HT-29 cells were 7.0% ± 1.3%, 15.6% ± 3.6% and 26.4% ± 6.2% respectively. 80×10^-6. 160×10^-6 mol/L quercetin acted on HT-29 cell, the cells at period G₀/G₁ and the apoptosis rates were significantly increased (P < 0.01), and the cells at period S were significantly decreased (P < 0.01) after 80×10^-6 and 160×10^-6 mol/L quercetin treatment. Quercetin at concentrations of 80×10^-6 and 160×10^-6 mol/L increased the expression of Caspase-3 and bax mRNA and Caspase-3 protein, but decreased the expression of bcl-2 mRNA. Quercetin at a concentration of 40×10^-6 mol/L increased Caspase-3 mRNA expression and the proliferation of HT-29 cells, but not Caspase-3 protein expression.

CONCLUSION: Quercetin at lower concentrations can promote the proliferation of colon carcinoma cell line HT-29 while it can inhibit the proliferation and induce apoptosis of HT-29 cells at higher concentrations. The mechanism may be associated with up-regulation of Caspase-3 and bax and down-regulation of bcl-2 expression.

Mechanism of acetaminophen-induced hepatocellular injury

AIM: To investigate the role of hepatocellular apoptosis in hepatitis induced by acetaminophen (AAP).

METHODS: The Sprague Dawley (SD) rat model of acetaminophen-induced hepatitis was established using AAP. After administration, the rats were killed at the end of 3, 6, 12, and 24 h, respectively. In both AAP and control group, we detected levels of serum alanine transaminase (ALT), observed pathological changes of hematoxylin and eosin (HE) stained liver with light microscope, and detected hepatocellular apoptosis using TUNEL method and electron microscopy.

RESULTS: The level of serum ALT (nkat/L) in AAP group was significantly higher than that in control group (3, 6, 12, 24 h: 1167 ± 151 vs 587 ± 89, 2154 ± 255 vs 573 ± 76, 4221 ± 929 vs 751 ± 82, 13203 ± 1393 vs 780 ± 161, all P < 0.01), which increased progressively and reached the peak at 24 h. In AAP group, different degrees of necrosis was detected and aggravated progressively, and it also reached the peak at 24 h. There were a large number of apoptotic hepatocytes around central veins and they reached the peak at 12 h in AAP group. However, few apoptotic hepatocytes were observed in control group. The apoptotic index (AI) in AAP group was markedly higher than that in control group (3, 6, 12, 24 h: 13.1% ± 2.9% vs 1.8% ± 0.5%, 24.8% ± 5.3% vs 1.7% ± 0.5%, 40.4% ± 3.7% vs 2.0% ± 0.4%, 35.3% ± 3.5% vs 1.92% ± 0.3%, P < 0.01). Electron microscopy indicated that hepatocytes of AAP group demonstrated unequivocal appearance of apoptotic traits, especially at 12 h.

CONCLUSION: Both apoptosis and necrosis exist in AAP-induced hepatocytic injury. Apoptosis was dominant in the early stage (within 12 h) while necrosis was dominant in the late stage (at 24 h).

Relationship between somatostatin receptor subtype expression and clinicopathology, Ki-67, Bcl-2 and p53 in colorectal cancer

AIM: To study the SSTR1, 2, 3, 4, 5 expression and their relationships with clinico-pathological factors, cell proliferation, Bcl-2 and p53 expression in colorectal cancer cells.

METHODS: Immunohistochemical staining of five SSTR subtypes, Ki-67, Bcl-2 and p53 was performed by the standard streptavidin-peroxidase (SP) technique for the paraffin sections of 127 colorectal cancers. and expression of five SSTR subtypes in 40 specimens of normal colorectal mucosae was detected with the same method.

RESULTS: Positive staining for five SSTR subtypes was observed in colorectal cancer cells and normal colorectal mucosae. SSTR1 was the most predominant subtype in both colorectal cancer and normal colorectal mucosa, and the second was SSTR5 or SSTR2. As compared with normal colorectal mucosa, SSTR4 was more frequently expressed in colorectal cancer cells (2.5 % vs 18.9 %, P  <  0.05); the expression of SSTR2, 4, 5 in moderately to well differentiated colorectal adenocarcinoma was significantly higher than that in poorly differentiated ones (P  <  0.05), the SSTR1 expression in colorectal cancer with positive lymph node metastasis was significantly higher than that with negative lymph node metastasis (72.2 % and 54.5 %，P <  0.05). In addition, in the ulcerative type of colorectal cancer, SSTR2 expression was obviously decreased (P   <  0.05); the correlation did not reach a statistical significance between the five SSTR subtypes expression and Dukes’stages (P  >  0.05), but the frequency of SSTR1 expression increased with Dukes’ stage, while SSTR3 and SSTR5 expression decreased with Dukes’ stage. Moreover, there was no correlation between expression of the five SSTR subtypes and other clinicopathological factors such as age, sex, tumor site, tumor depth, distant metastasis. The proliferative indexes in colorectal cancer cells with negative expression of SSTR2 and SSTR3 were significantly higher than that with positive expression (P < 0.05). The Bcl-2 expression in colorectal cancer cells with positive expression of SSTR1, 2, 3, 5 was significantly lower than that with negative expression (P < 0.05). There was no correlation between five SSTR subtypes and p53 expression.

CONCLUSION: The most predominant SSTR subtype is SSTR1, and the second is SSTR2 or SSTR5. Five SSTR subtypes play different roles in the development of colorectal cancer. SSTR2 and SSTR3 can inhibit the proliferation and promote apoptosis of tumor cells.

Effect of Chinese medicine Qinggan Huoxuefang on inducing HSC apoptosis in alcoholic liver fibrosis rats

AIM: To investigate the effect of Qinggan Huoxuefang (QGHXF) on improvement of liver function and pathology in rats, and to analyze the mechanism.

METHODS: Wistar rats were divided into three groups at random: normal control group (12),micro-amount carbon tetrachloride group (CCl₄)(12) and model group A (60). The model group A was ingested with the mixture (500 mL/L alcohol, 8 mL/kg per day; corn oil, 2 mL/kg per day; pyrazole, 24 mg/kg per day) once a day and intraperitoneal injections of 0.25 mL/kg of a 250 mL/L solution of CCl₄ in olive oil twice a week for 12 wk. The CCl₄ group received intraperitoneal injections only. At the end of 8 wk the model group A (60) was divided into 5 subgroups: model group, Xiaochaihu Chongji (XCH) group, QGHXF high dose group, moderate dose group and low dose group, and were given the drugs respectively. At the end of 12 wk, all the rats were killed and blood samples collected, as well as liver tissue. Blood samples were used for evaluation of alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyltransferase (γ-GT). Liver specimens were obtained for routine HE, apoptosis gene array and flow cytometry analysis.

RESULTS: A liver fibrosis animal model was successfully established. Fibrosis was obviously reduced in QGHXF high dose group, and no fibrosis formed in CCl₄ group. Compared with model group the QGHXF group and XCH group could obviously decrease the level of ALT, AST, ALP, and GGT (P  < 0.05). QGHXF high dose group was better than XCH group in ALT (615 ± 190 vs 867 ± 115), and AST(1972 ± 366 vs 2777 ± 608). Moreover, QGHXF could reduce liver inflammation, fibrosis-induced hepatic stellate cell (HSC) apoptosis and regulate apoptosis gene expression. The HSC apoptosis rates of QGHXF groups were 22.4 ± 3.13, 13.79 ± 2.26 and 10.07 ± 1.14, higher than model group, 6.58±1.04 (P  <  0.05). Compared to model group, 39 genes were up-regulated, 11 solely expressed and 17 down-regulated in high dose group.

CONCLUSION: QGHXF can improve liver fibrosis and induce HSC apoptosis.

S-adenosyl-methionine decreases ethanol-induced apoptosis in primary hepatocyte cultures by a c-Jun N-terminal kinase activity-independent mechanism

AIM: To determine the role of c-Jun N-terminal kinase (JNK) activity in ethanol-induced apoptosis and the modulation of this signaling cascade by S-Adenosyl-methionine (AdoMet).

METHODS: Primary hepatocyte cultures were pretreated with 100 µmol/L SP600125, a selective JNK inhibitor, 1 mL/L DMSO or 4 mmol/L AdoMet and then exposed to 100 mmo/L ethanol. Hepatocyte apoptosis was determined by the TUNEL and DNA ladder assays. JNK activity and its inhibition by SP600125 and AdoMet were determined by Western blot analysis of c-jun phosphorylation and Bid fragmentation. SP600125 and AdoMet effects on the apoptotic signaling pathway were determined by Western blot analysis of cytochrome c release and pro-caspase 3 fragmentation. The AdoMet effect on glutathione levels was measured by Ellman’s method and reactive oxygen species (ROS) generation by cell cytometry.

RESULTS: The exposure of hepatocytes to ethanol induced JNK activation, c-jun phosphorylation, Bid fragmentation, cytochrome c release and pro-caspase 3 cleavage; these effects were diminished by SP600125, and caused a significant decrease in ethanol-induced apoptosis (P< 0.05). AdoMet exerted an antioxidant effect maintaining glutathione levels and decreasing ROS generation, without a significant effect on JNK activity, and prevented cytochrome c release and pro-caspase 3 cleavage.

CONCLUSION: The JNK signaling cascade is a key component of the proapoptotic signaling pathway induced by ethanol. JNK activation may be independent from ROS generation, since AdoMet which exerted antioxidant properties did not have a significant effect on JNK activity. JNK pathway modulator agents and AdoMet may be components of promising therapies for alcoholic liver disease (ALD) treatment.

Toxicity assay for recombinant protein of rhTRAIL55-281 and GST-rhTRAIL55-281 to hepatic cells

AIM: To investigate the toxicity of recombinant protein rhTRAIL_55-281 and GST-rhTRAIL_55-281 to human hepatic cells, and to provide the experi-ment evidence for development of anti-tumor drugs.

METHODS: Primary cultured human hepatic cells were obtained from adult and fetus by trypsin digestion and mechanical separation. GST tag was cut off by Factor-Xa from recombinant protein GST-rhTRAIL_55-281 to gain rhTRAIL_55-281. Human hepatic cell strain L-02, primary cultured human hepatic cells from adult and fetus and normal human peripheral blood mononuclear cells (PBMCs) were intervened by recombinant protein rhTRAIL_55-281 or GST-rhTRAIL_55-281, and finally the apoptosis of cells were detected by flow cytometry.

RESULTS: The viability of primary cultured human hepatic cells from adult and fetus exceed 95%, and the purity of rhTRAIL_55-281 without GST tag was 97%. Mass of apoptosis was detected in L-02, adult human hepatocytes and human fetal hepatocytes, and the apoptosis rates were 79.1%, 72.8%, and 42.2% or 80.3%, 74.7%, and 47.2%, respectively, 48 h after rhTRAIL_55-281or GST-rhTRAIL_55-281 intervention at concentration of 10 mL/L. However, PBMCs showed little apoptosis.

CONCLUSION: Recombinant protein rhTRAIL_55-281 or GST-rhTRAIL_55-281 is limited in the development of antineoplastics due to its hepatocyte toxicity.

Melanoma differentiation-associated gene-7, MDA-7/IL-24, selectively induces growth suppression, apoptosis in human hepatocellular carcinoma cell line HepG2 by replication-incompetent adenovirus vector

AIM: To investigate the effect of replication-incompetent adenovirus vector expressing MDA-7/IL-24 on tumor growth and apoptosis in human hepatocellular carcinoma (HCC) cell line HepG2 and normal liver cell line L02.

METHODS: We constructed the recombinant replication-incompetent Ad.mda-7 virus vector and infected it into the human HCC cell line HepG2 and normal liver cell line L02. RT-PCR was performed to detect the mRNA expressing in cells. by ELISA was used to detect MDA-7/IL-24 protein expression in the culture supernatant. The effect of apoptosis induced by Ad.mda-7 was confirmed by Hoechst staining and flow cytometry assay with Annexin-V and PI staining. MTT assay was used to determine growth inhibition of HepG2 cells, and cell-cycle and hypodiploidy analyses were performed by flow cytometry.

RESULTS: Recombinant replication-defective virus expressing MDA-7/IL-24 was constructed successfully. RT-PCR showed that the Ad.mda-7 could mediate the expression of the exogenous gene MDA-7/IL-24 into HepG2 and L02. The concentration of MDA-7/IL-24 protein in supernatant was 130 pg/mL and 110 pg/mL in Ad.mda-7-infected L02 and HepG2 cells, respectively. Ad.mda-7 infection obviously induced apoptosis (from 2.60±0.72% to 33.6±13.2%, P  = 0.00012) and growth suppression in HepG2 (inhibition ratio IR = 68%) and an increase in the percentage of specific cancer cell types at the G2/M phase of the cell cycle (from 6.44% to 32.29%, P < 0.01), but not in L02 cells.

CONCLUSION: These results confirm selectively induction of apoptosis and growth suppression by the mda-7/IL-24 gene with replication-incompetent adenovirus vector in human hepatocellular carcinoma cell line HepG2.

Chronic hepatitis B serum promotes apoptotic damage in human renal tubular cells

AIM: To investigate the effect of the serum of patients with chronic hepatitis B (CHB) on apoptosis of renal tubular epithelial cells in vitro and to study the role of hepatitis B virus (HBV) and transforming growth factor-β1 (TGF-β1) in the pathogenesis of hepatitis B virus associated glomerulonephritis (HBV-GN).

METHODS: The levels of serum TGF-β₁ were measured by specific enzyme linked immunosorbent assay (ELISA) and HBV DNA was tested by polymerase chain reaction (PCR) in 44 patients with CHB ,and 20 healthy persons as the control. The normal human kidney proximal tubular cell (HK-2) was cultured together with the sera of healthy persons, CHB patients with HBV-DNA negative(20 cases) and HBV-DNA positive (24 cases) for up to 72 h. Apoptosis and Fas expression of the HK-2 were detected by flow cytometer.

RESULTS: The apoptosis rate and Fas expression of HK-2 cells were significantly higher in HBV DNA positive serum group 19.01±5.85% and 17.58±8.35%, HBV DNA negative serum group 8.12±2.80% and 6.96 ± 2.76% than those in control group 4.25±0.65% and 2.33 ±1.09%, respectively (P < 0.01). The apoptosis rate and Fas expression of HK-2 in HBV DNA positive serum group was significantly higher than those in HBV DNA negative serum (P < 0.01). Apoptosis rate of HK-2 cells in HBV DNA positive serum group was positively correlated with the level of HBV-DNA (r = 0.657). The level of serum TGF-β₁ in CHB group was 163.05 ± 91.35 µg/L, significantly higher as compared with 81.40 ± 40.75 µg/L in the control group (P < 0.01).

CONCLUSION: The serum of patients with chronic hepatitis B promotes apoptotic damage in human renal tubular cells by triggering a pathway of Fas up-regulation. HBV and TGF-β₁ may play important roles in the mechanism of hepatitis B virus associated glomerulonephritis.

Relaxin prevents the development of severe acute pancreatitis

AIM: To investigate the severity of acute pancreatitis (AP) is associated to the intensity of leukocyte activation, inflammatory up-regulation and microcirculatory disruption associated to ischemia-reperfusion injury. Microvascular integrity and inhibition of pro-inflammatory mediators are key-factors in the evolution of AP. Relaxin is an insulin-like hormone that has been attributed vasorelaxant properties via the nitric oxide pathway while behaving as a glucocorticoid receptor agonist.

METHODS: AP was induced by the bilio-pancreatic duct-outlet-exclusion closed-duodenal-loops model. Treatment with relaxin was done at different time-points. Nitric oxide synthase inhibition by L-NAME and glucocorticoid receptor (GR) blockage by mifepristone was considered. AP severity was assessed by biochemical and histopathological analyses.

RESULTS: Treatment with relaxin reduced serum amylase, lipase, C-reactive protein, IL-6, IL-10, hsp72, LDH and 8-isoprostane as well as pancreatic and lung myeloperoxidase. Acinar and fat necrosis, hemorrhage and neutrophil infiltrate were also decreased. ATP depletion and ADP/ATP ratio were reduced while caspases 2-3-8 and 9 activities were increased. L-NAME and mifepristone decreased the efficiency of relaxin.

CONCLUSION: Relaxin resulted beneficial in the treatment of AP combining the properties of a GR agonist while preserving the microcirculation and favoring apoptosis over necrosis.

Apoptosis induced by preoperative oral 5’-DFUR administration in gastric adenocarcinoma and its mechanism of action

AIM: To study the apoptosis induced by preoperative oral 5’-DFUR administration in gastric adenocarcinoma and its mechanism of action.

METHODS: Sixty gastric cancer patients were divided randomly into three groups (20 each group) before operation: group one: 5’-DFUR oral administration at the dose of 800-1200mg/d for 3 - 5 d, group two: 500mg 5-FU + 200 mg/d CF by venous drip for 3 - 5 d, group three (control group). One or two days after chemotherapy, the patients were operated. Fas/FasL, PD-ECGF and PCNA were examined by immunohistochemistry and apoptotic tumor cells were detected by in situ TUNEL method. Fifty-four patients received gastrectomy, including 12 palliative resections and 42 radical resections. Six patients were excluded. Finally 18 cases in 5’-DFUR group, 16 cases in CF + 5-FU group, and 20 cases in control group were analyzed.

RESULTS: There was no significant difference in patient mean age, gender, white blood cell count, haematoglobin (HB), thromboplastin, perioperative complication incidence, radical or palliation resection, invasion depth (T), lymphonode involvement (N), metastasis (M) and TNM staging among the three groups. However, the PCNA index (PI) in 5’-DFUR group (40.51 ± 12.62) and 5-FU + CF group (41.12 ± 15.26) was significantly lower than that in control group (58.33 ± 15.69) (F = 9.083, P = 0.000). The apoptotic index (AI) in 5’-DFUR group (14.39 ± 9.49) and 5-FU + CF group (14.11±9.68) was significantly higher than that in control group (6.88 ± 7.37) (F = 4.409, P = 0.017). The expression rates of Fas and FasL in group one and group three were 66.7% (12/18) and 50% (9/18), 43.8% (7/16) and 81.3% (13/16), 45.0% (9/20) and 85% (17/20), respectively. The expression rate of FasL in 5’-DFUR group was significantly lower than that in the other two groups (χ²=6.708, P = 0.035). Meanwhile, the expression rate of PD-ECGF was significantly lower in 5’-DFUR group (4/18，28.6%) than in CF + 5-FU group（9/16，56.3%）and control group (13/20，65.0%) (χ²= 7.542, P = 0.023). The frequency of Fas expression was significantly correlated with palliative or radical resection (χ²= 7.651, P = 0.006), invasion depth (χ²= 8.927, P = 0.003), lymphatic spread (χ²= 4.488, P = 0.034) and UICC stages (χ²= 8.063, P = 0.045) respectively. By the end of March 2005, 45 patients were followed up. The 0.5-, 1-, 2-, 3-year survival rates were 96%，73%，60%，48%, respectively, which were related with T, N, M and Fas expression, but not with PD-ECGF and FasL expression.

CONCLUSION: Preoperative oral 5’-DFUR administration may induce apoptosis of gastric carcinoma cells and decrease tumor cell proliferation index, but cannot improve the prognosis of patients with gastric cancer. Down-regulation of FasL and PD-ECGF expression mediated by 5’-DFUR may be one of its anti-cancer mechanisms. Fas expression correlates with the progression of gastric carcinoma and may be an effective prognostic factor.

Resveratrol at high doses acts as an apoptotic inducer in endothelial cells

PURPOSES

Resveratrol is a phenolic compound found in grapes and other food products. In order to assess the availability of resveratrol as an angio-inhibiting drug, we examined whether resveratrol plays an important role in bovine aortic endothelial cells (BAECs) for cell apoptosis and cell migration.

METHODS AND MATERIALS

Endothelial cell apoptosis was observed as detected by the Hoechst staining and the caspase-3 activity. Additionally, Western blotting was performed for monitoring the activities of various cell signaling molecules.

RESULTS

Resveratrol was shown to act as a pro-apoptotic agent. The pro-apoptotic effect of resveratrol was as great as that of etoposide, a well-known anti-cancer drug. In addition, resveratrol had an inhibitory effect on endothelial cell migration. The demonstrated efficacy of resveratrol suggests that resveratrol may be utilized as an anti-angiogenic drug. To determine the underlying mechanisms, we further investigated which signaling molecules are activated by resveratrol. Extracellular signal-regulated kinase (ERK) was activated by the treatment with resveratrol in BAECs, whereas endothelial nitric oxide synthetase (eNOS), Akt, and Jun N-terminal kinase (JNK) were inhibited. The pretreatment with PD compound, an ERK inhibitor, had no effect on the pro-apoptosis induced by resveratrol.

CONCLUSION

Resveratrol plays an important role in endothelial cell apoptosis, indicating that resveratrol can be utilized as a potent anti-angiogenic drug.

Arsenic trioxide induces apoptosis in human colorectal adenocarcinoma HT-29 cells through ROS

PURPOSE

Treatment with arsenic trioxide (As(2)O(3)) results in a wide range of cellular effects that includes induction of apoptosis, inhibition of cell growth, promotion or inhibition of cellular differentiation, and inhibition of angiogenesis through a variety of mechanisms. The mechanisms of As(2)O(3)-induced cell death have been mainly studied in hematological cancers, and those mechanisms in solid cancers have yet to be clearly defined. In this study, the mechanisms by which As(2)O(3) induces apoptosis in human colorectal adenocarcinoma HT-29 cells were investigated.

MATERIALS AND METHODS

To examine the levels of apoptosis, HT-29 cells were treated with As(2)O(3) and then we measured the percentage of Annexin V binding cells, the amount of ROS production and the mitochondrial membrane potential. Western blot analysis was performed to identify the activated caspases after As(2)O(3) exposure, and we compared the possible target molecules of apoptosis. As(2)O(3) treatment induced the loss of the mitochondrial membrane potential and an increase of ROS, as well as activation of caspase-3, -7, -9 and -10.

RESULTS

As(2)O(3) induced apoptosis via the production of reactive oxygen species and the loss of the mitochondrial membrane potential. As(2)O(3) induced the activation of caspase-3, -7, -9 and -10. Furthermore, As(2)O(3) treatment downregulates the Mcl-1 and Bcl-2 expressions, and the release of cytochrome c and an apoptosis-inducing factor (AIF). Pretreating the HT-29 cells with N-acetyl-L-cysteine, which is a thiol-containing antioxidant, inhibited the As(2)O(3)-induced apoptosis and caspase activation.

CONCLUSION

Taken together, these results suggest that the generation of reactive oxygen species (ROS) by As(2)O(3) might play an important role in the regulation of As(2)O(3)-induced apoptosis. This cytotoxicity is mediated through a mitochondria-dependent apoptotic signal pathway in HT-29 cells.

DNA damage, apoptosis and cell cycle changes induced by fluoride in rat oral mucosal cells and hepatocytes

AIM: To study the effect of fluoride on oxidative stress, DNA damage and apoptosis as well as cell cycle of rat oral mucosal cells and hepatocytes.

METHODS: Ten male SD rats weighing 80~120 g were randomly divided into control group and fluoride group, 5 animals each group. The animals in fluoride group had free access to deionized water containing 150 mg/L sodium fluoride (NaF). The animals in control group were given distilled water. Four weeks later, the animals were killed. Reactive oxygen species (ROS) in oral mucosa and liver were measured by Fenton reaction, lipid peroxidation product, malondialdehyde (MDA), was detected by thiobarbituric acid (TBA) reaction, reduced glutathione (GSH) was assayed by dithionitrobenzoic acid (DTNB) reaction. DNA damage in oral mucosal cells and hepatocytes was determined by single cell gel (SCG) electrophoresis or comet assay. Apoptosis and cell cycle in oral mucosal cells and hepatocytes were detected by flow cytometry.

RESULTS: The contents of ROS and MDA in oral mucosa and liver tissue of fluoride group were significantly higher than those of control group (P < 0.01), but the level of GSH was markedly decreased (P < 0.01). The contents of ROS, MDA and GSH were (134.73 ± 12.63) U/mg protein, (1.48 ± 0.13) mmol/mg protein and (76.38 ± 6.71) mmol/mg protein in oral mucosa respectively, and (143.45 ±11.76) U/mg protein, (1.44 ± 0.12) mmol/mg protein and (78.83 ± 7.72) mmol/mg protein in liver tissue respectively. The DNA damage rate in fluoride group was 50.20% in oral mucosal cells and 44.80% in hepatocytes, higher than those in the control group (P < 0.01). The apoptosis rate in oral mucosal cells was (13.63 ± 1.81) % in fluoride group, and (12.76 ± 1.67) % in hepatocytes, higher than those in control group. Excess fluoride could differently lower the number of oral mucosal cells and hepatocytes at G₀/G₁ and S G₂/M phases (P < 0.05).

CONCLUSION: Excess fluoride can induce oxidative stress and DNA damage and lead to apoptosis and cell cycle change in rat oral mucosal cells and hepatocytes.

PI 3-kinase pathway is responsible for antiapoptotic effects of atrial natriuretic peptide in rat liver transplantation

AIM: To investigate the in vivo effect of atrial natriuretic peptide (ANP) and its signaling pathway during orthotopic rat liver transplantation.

METHODS: Rats were infused with NaCl, ANP (5 µg/kg), wortmannin (WM, 16 µg/kg), or a combination of both for 20 min. Livers were stored in UW solution (4 °C) for 24 h, transplanted and reperfused. Apoptosis was examined by caspase-3 activity and TUNEL staining. Phosphorylation of Akt and Bad was visualized by Western blotting and phospho-Akt-localization by confocal microscopy.

RESULTS: ANP-pretreatment decreased caspase-3 activity and TUNEL-positive cells after cold ischemia, indicating antiapoptotic effects of ANP in vivo. The antiapoptotic signaling of ANP was most likely caused by phosphorylation of Akt and Bad, since pretreatment with PI 3-kinase inhibitor WM abrogated the ANP-induced reduction of caspase-3 activity. Interestingly, analysis of liver tissue by confocal microscopy showed translocation of phosphorylated Akt to the plasma membrane of hepatocytes evoked by ANP.

CONCLUSION: ANP activates the PI-3-kinase pathway in the liver in vivo leading to phosphorylation of Bad, an event triggering antiapoptotic signaling cascade in ischemic liver.

Effects of Terminalia arjuna bark extract on apoptosis of human hepatoma cell line HepG2

AIM: To investigate the effects of Terminalia arjuna (T. arjuna) extract on human hepatoma cell line (HepG2) and its possible role in induction of apoptosis.

METHODS: Human hepatoma cells were treated with different concentrations of ethanolic extract of T. arjuna and its cytotoxicity effect was measured by trypan blue exclusion method and lactate dehydrogenase leakage assay. Apoptosis was analyzed by light and fluorescence microscopic methods, and DNA fragmentation. The mechanism of apoptosis was studied with expression of p53 and caspase-3 proteins. Glutathione (GSH) content was also measured in HepG2 cells after T. arjuna treatment.

RESULTS: T. arjuna inhibited the proliferation of HepG2 cells in a concentration-dependent manner. Apoptotic morphology was observed in HepG2 cells treated with T. arjuna at the concentrations of 60 and 100 mg/L. DNA fragmentation, accumulation of p53 and cleavage of procaspase-3 protein were observed in HepG2 cells after the treatment with T. arjuna. The depletion of GSH was observed in HepG2 cells treated with T. arjuna.

CONCLUSION: T. arjuna induced cytotoxicity in HepG2 cells in vitro. Apoptosis of HepG2 cells may be due to the DNA damage and expression of apoptotic proteins. Depletion of GSH may be involved in the induction of apoptosis of HepG2 cells.

Chronic low vitamin intake potentiates cisplatin-induced intestinal epithelial cell apoptosis in WNIN rats

AIM: To investigate if cisplatin alters vitamin status and if VR modulates cisplatin induced intestinal apoptosis and oxidative stress in Wistar/NIN (WNIN) male rats.

METHODS: Weanling, WNIN male rats (n = 12 per group) received adlibitum for 17 wk: control diet (20% protein) or the same with 50% vitamin restriction. They were then sub-divided into two groups of six rats each and administered cisplatin (2.61 mg/kg bodyweight) once a week for three wk or PBS (vehicle control). Intestinal epithelial cell (IEC) apoptosis was monitored by morphometry, Annexin-V binding, M30 cytodeath assay and DNA fragmentation. Structural and functional integrity of the villus were assessed by villus height / crypt depth ratio and activities of alkaline phosphatase, lys, ala-dipeptidyl amino-peptidase, respectively. To assess the probable mechanism(s) of altered apoptosis, oxidative stress parameters, caspase-3 activity, and expression of Bcl-2 and Bax were determined.

RESULTS: Cisplatin per se decreased plasma vitamin levels and they were the lowest in VR animals treated with cisplatin. As expected VR increased only villus apoptosis, whereas cisplatin increased stem cell apoptosis in the crypt. However, cisplatin treatment of VR rats increased apoptosis both in villus and crypt regions and was associated with higher levels of TBARS, protein carbonyls and caspase-3 activity, but lower GSH concentrations. VR induced decrease in Bcl-2 expression was further lowered by cisplatin. Bax expression, unaffected by VR was increased on cisplatin treatment. Mucosal functional integrity was severely compromised in cisplatin treated VR-rats.

CONCLUSION: Low intake of vitamins increases the sensitivity of rats to cisplatin and promotes intestinal epithelial cell apoptosis.

Apoptosis of human hepatocellular carcinoma cell line HepG2 induced by composite Gan'aining medicated serumin vitro

AIM: To investigate the efficacy of compsite Gan'aining (CGN) in inducing the apoptosis of human hepatocellular carcinoma (HCC) cell line HepG₂in vitro.

METHODS: Human HCC HepG₂ cells were co-cultured with non-medicated serum, 5-FU medicated serum, and different concentrations of CGN medicated serum, respectively. The apoptosis of HepG₂ cells was detected by TUNEL and flow cytometry (FCM), respectively.

RESULTS: CGN medicated serum at different concentrations inhibited the growth of HepG₂ cells in vitro. After treatment with CGN, typical features of apoptosis such as apoptotic body were observed under light microscope. High-, moderate- and low-dose CGN medicated serum induced apoptotic rates (by TUNEL) of 14.5% ± 1.81%, 13.61% ± 1.78% and 10.19% ± 1.77%, respectively, which were significantly higher than that induced by non-medicated serum (0.74% ± 0.12%)(all P < 0.01). The sub-G₁ peaks were observed by FCM in CGN treated cells and the apoptosis rates of the cells treated with high-, moderate- and low-dose CGN medicated serum were 15.1%, 12%, and 5.5%, respectively, which were markedly higher than that of the cells treated with non-medicated serum (1.0%)(P< 0.01 or P < 0.05).

CONCLUSION: CGN can induce the apoptosis of human HCC cells in vitro in a dose-dependent manner

Inhibitory effects of interferons on pancreatic stellate cell activation

AIM: To analyze and to compare the effects of interferon (IFN)-α, IFN-β, and IFN-γ on pancreatic stellate cell (PSC) activation in vitro and to elucidate the molecular basis of IFN action.

METHODS: PSCs were isolated from rat’s pancreatic tissue, cultured and stimulated with recombinant rat IFNs. Cell proliferation and collagen synthesis were assessed by measuring the incorporation of 5-bromo-2’-deoxyuridine (BrdU) into DNA and [³H]-proline into acetic acid-soluble proteins, respectively. Apoptotic cells were determined by FACS analysis (sub-G₁ peak method). Exhibition of the myofibroblastic PSC phenotype was monitored by immunoblot analysis of α-smooth muscle actin (α-SMA) expression. To assess the activation of signal transducer and activator of transcription (STAT), Western blots using phospho-STAT-specific antibodies were performed. In studies on STAT1 function, expression of the protein was inhibited by siRNA.

RESULTS: IFN-β and IFN-γ, but not IFN-α significantly diminished PSC proliferation and collagen synthesis. IFN-γ was the only IFN that clearly inhibited α-SMA expression. Under the experimental conditions used, no enhanced rate of apoptotic cell death was observed in response to any IFN treatment. IFN-β and IFN-γ induced a strong increase of STAT1 and STAT3 tyrosine phosphorylation, while the effect of IFN-α was much weaker. Inhibition of STAT1 expression with siRNA was associated with a significantly reduced growth-inhibitory effect of IFN-γ.

CONCLUSION: IFN-β and particularly IFN-γ display inhibitory effects on PSC activation in vitro and should be tested regarding their in vitro efficiency. Growth inhibition by IFN-γ action requires STAT1.

Construction of retroviral vector of p125FAK specific ribozyme genes and its effects on BGC-823 cells

AIM: To construct the retroviral vector of p^125FAK specific ribozyme genes and to explore the feasibility of ribozyme in BGC-823 gene therapy in vitro.

METHODS: A hammerhead ribozyme DNA targeting p^125FAK mRNA from nt 1010 to nt 1032 was synthesized and recombinated into the retroviral vector pLXSN forming pLRZXSN recon. Using the lipofectin-mediated DNA transfection technique, pLRZXSN was introduced into BGC-823 cells. The effects of ribozyme on the growth of BGC-823 cells and apoptosis were studied by cell colony assay, flow cytometry (FCM), reverse transcriptase-polymerase chain reaction (RT-PCR), detection of DNA fragmentation and electron microscopy.

RESULTS: The number of BGC-823 cell colonies was inhibited by 56% after the cells were treated for 48 h. The cell proliferation was inhibited effectively by p^125FAK ribozyme and the inhibitory effect depended on the concentration and the time of incubation. The expression of p^125FAK mRNA and protein P¹²⁵ decreased sharply in BGC-823 cells treated with p^125FAK ribozyme. The characteristics of apoptosis, namely sub-G1 peak, DNA fragmentation and morphological changes, were revealed in BGC-823 cells treated with p^125FAK ribozyme.

CONCLUSION: p^125FAK ribozyme decreases p^125FAK gene expression and induces apoptosis of human gastric cancer cells in vitro.

Effects of 5-Aza-CdR on cell proliferation and apoptosis in colonic cancer cell line Lovo and expression of tumor suppressor gene RUNX3

AIM: To investigate the effects of 5-Aza-2'-deoxycytidine (5-Aza-CdR) on the proliferation and apoptosis of Lovo cells and the expression of tumor suppressor gene RUNX3.

METHODS: Human colonic cancer cell line Lovo was treated with 5-Aza-CdR (0.4, 4, 40 μmol/L), a specific demethylating agent, for 3 d, and then cultured in RPMI 1640 medium for 5 d. The growth of Lovo cells was observed by MTT assay before and after 5-Aza-CdR treatment, respectively. The expression of RUNX3 mRNA was observed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The apoptosis of Love cells was analyzed by flow cytometry.

RESULTS: Lovo cells treated with 5-Aza-CdR displayed a slowed growth in comparison with the control cells, and the growth rate decreased accordingly with the increase of 5-Aza-CdR concentration. RUNX3 mRNA was expressed in Lovo cells after 5-Aza-CdR treatment, but it was undetectable before the treatment. After 0.4, 4, and 40 μmol/L 5-Aza-CdR treatment, the level of RUNX3 mRNA expression was 0.46 ± 0.06, 0.71 ± 0.06, and 0.84 ± 0.07, respectively, and it was significantly correlated with the concentration of 5-Aza-CdR (F = 168.4, P < 0.01). The apoptotic rate of Lovo cells treated with 0.4, 4, and 40 μmol/L 5-Aza-CdR was 10.95% ± 2.09%, 17.61% ± 1.51%, and 26.60% ± 1.89%, respectively, which was markedly higher than that of the controls (2.92% ± 0.93%)(P < 0.01). The apoptosis was also notably correlated with 5-Aza-CdR concentration (F = 145.7, P < 0.01).

CONCLUSION: 5-Aza-CdR can inhibit the proli-feration and partly induce the apoptosis of Lovo cells by inducing the re-expression of RUNX3 gene..

Effects of rhubarb polysacchrides on apoptosis of colonic epithelial cells and peripheral blood polymorphonuclear neutrophils in mice with ulcerative colitis

AIM: To investigate the effects of rhubarb polysac-chrides (RP) on the apoptosis of colonic epithelial cells and peripheral blood polymorphonuclear neutrophils (PMN) in mice with ulcerative colitis, and to explore the mechanisms of RP in the treatment of ulcerative colitis.

METHODS: A mouse mode1 of ulcerative colitis was induced with 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) by enema. The mice were divided into three groups: nomal control, model, and RP treatment (400 mg/kg) group. TUNEL method was used to investigate the apoptosis of cells in colon, and the expression of Fas and FasL protein were measured by Western-blot. The level of Caspase 3 expression was detected by immunohistochemistry. Meanwhile, flow cytometry was used to examine the apoptosis of PMN.

RESULTS: The apoptosis level of colonic epithelial cells was dramatically higher in the model mice than that in the normal controls, while the rate of PMN apoptosis was significantly lower in the former (40.5 ± 7.8% vs 57.7 ± 8.2%, P < 0.01). However, the apoptosis level of colonic epithelial cells in RP treated mice was markedly lower than that in the model group, while the rate of PMN apoptosis was notably higher in the former (46.3 ± 6.5% vs 40.5 ± 7.8%, P < 0.01). In model group, the expression of Caspase 3, Fas, and FasL protein were significantly increased in comparison with those in the normal controls, but 3 d after treatment with RP, the expression of Caspase 3, Fas, and FasL protein were remarkably decreased as compared with those in the model mice.

CONCLUSION: Rhubarb polysacchrides can protect the intestinal tract against ischemic inflammation by down-regulation of Caspase-3 expression, which leads to the inhibition of apoptosis induced by Fas/FasL pathway.

Effects of matrine on apoptosis of hepatocytes and expression of regulating gene during cold preservation and reperfusion injury in rat donor liver

AIM: To investigate the effect of Matrine on the apoptosis of hepatocytes and expression of regulating gene during cold preservation and reperfusion injury in rat orthotopic liver trans-plantation (OLT).

METHODS: Eighty-four syngeneic SD rats were randomly divided into control, Matrine, and pseudo-treatment group. The rats in Matrine group were treated with low (40 mg/kg) and high dose (80 mg/kg) of Matrine, respectively. After the donor liver was preserved in Ringer's (LR) solution for 5 h, the orthotopic implantation was performed. Four and 24 h after reperfusion of the portal vein, the serum and tissue samples were collected for analysis. The cell apoptosis was detected by TUNEL, and the expression of Fas-L and Bcl-2 protein were determined by flow cytometry. The histopathological changes were observed under light and electron microscope.

RESULTS: In comparison with that in the control group, the apoptosis index was significantly de-creased in low and high dose Matrine treatment group (6.07 ± 1.68, 6.17 ± 0.83 vs 14.87 ± 2.10, P < 0.01), while the level of Bcl-2 expression was markedly elevated (59.32 ± 14.09, 58.90 ± 16.70 vs 17.00 ± 8.01, P < 0.01). The expression of FasL was not notably different between the control and Matrine group. The apoptosis index, Bcl-2 and FasL expression had no distinct difference between low and high dose treatment group either. The pathological changes of liver cells were severe in the control group, but they were obviously ameliorated in Matrine group.

CONCLUSION: Matrine can protect hepatocyts against apoptosis by inhibiting the Bcl-2 express-ion during cold preservation and reperfusion injury.

Exacerbations of chronic obstructive pulmonary disease and chronic mucus hypersecretion

Chronic obstructive pulmonary disease (COPD) exacerbations are an important cause of the considerable morbidity and mortality found in COPD. COPD exacerbations increase with increasing severity of COPD, and some patients are prone to frequent exacerbations leading to hospital admission and readmission. These frequent exacerbations may have considerable impact on quality of life and activities of daily living. Factors that increase the risk for COPD exacerbations are associated with increased airway inflammation caused by common pollutants and bacterial and/or viral infections. These inflammatory responses cause mucus hypersecretion and, thereby, airway obstruction and associated exacerbations. While chronic mucus hypersecretion is a significant risk factor for frequent and severe exacerbations, patients with chronic mucus hypersecretion have a lower rate of relapse after initial treatment for acute exacerbation. The benefit of antibiotics for treatment of COPD exacerbations is small but significant. While the mechanisms of actions are not clear, mucolytic agents reduce the number of days of disability in subjects with exacerbations. Reducing mucous cell numbers in small airways could be a useful way to reduce chronic mucus hypersecretion. Our studies suggest that programmed cell death is crucial in the resolution of metaplastic mucous cells, and understanding these mechanisms may provide novel therapies to reduce the risk of COPD exacerbations.

Relationship between intracellular Ca2+ and ALA-PDT induced apoptosis in SW480 cells

AIM: To investigate relationship between intracellular Ca²⁺ and apoptosis induced by aminolaevulinic acid-photodynamic therapy (ALA-PDT) in SW480 cells.

METHODS: SW480 cells were divided into control, light, ALA and ALA-PDT group. The corresponding treatment was performed in each group. The apoptosis of SW480 cells was detected by DNA fragment assay and TUNEL assay. The changes of intracelluar Ca²⁺ concentration in each group were observed by confocal laser scanning microscopy.

RESULTS: DNA ladder formation of apoptotic features was demonstrated 1 and 2 h after ALA-PDT treatment. The apoptosis index (AI) of 30 and 60 min after ALA-PDT treatment was 25.26% ± 5.04% and 50.45% ± 7.85%, respectively, which were significantly higher than those in the other 3 groups (all AI <10%, P < 0.01). The concentration of intracelluar Ca²⁺ 20 min after ALA-PDT treatment was markedly increased than that at 10 min (fluorescent intensity: 185.40 ± 18.90 vs 100.00 ± 19.83, P < 0.01), and then gradually decreased. However, the concentrations of intracelluar Ca²⁺ had no significant changes in the other 3 groups.

CONCLUSION: The increases of intracellular Ca²⁺ may play an important role in the ALA-PDT-induced apoptosis in SW480 cells.

Helicobacter pylori induces apoptosis of rat gastric epithelial cells in vitro

AIM: To investigate the effect of Helicobacter pylori (H. pylori) sonicated extract on the apoptosis of rat gastric epithelial cells as well as the expression of apoptosis-related genes in vitro.

METHODS: H. pylori sonicated extract from strain Sydney SS-1 was cultured with OUMS-37, a kind of immortalized rat gastric cell lines. Apoptosis of the cells was confirmed according to specific changes of morphology and DNA ladder 24-48 h after co-incubation. The expression of P53 protein was detected by Western blotting and the expression of bax and bcl-2 mRNA were observed by Northern blotting.

RESULTS: The specific morphology of the cells such as shrinkage, condensation, margination of nuclear chromatin and apoptotic bodies were observed under light microscope. DNA ladder was manifested by fragment analysis. Western blotting showed a dose-dependent increased expression of wild-type P53 protein and Northern blotting showed a dose-pendent increased expression of bax mRNA and reduced expression of bcl-2 mRNA in the treated cells.

CONCLUSION: H. pylori sonicated extract induces the apoptosis in vitro through up-regulation of wild-type P53 protein and bax mRNA expression, and down-regulation of bcl-2 mRNA expression, suggesting that H. pylori infection may interrupt the balance between proliferation and apoptosis of the gastric epithelial cells, which plays a key role in gastric carcinogenesis.

Liver injury and hepatocyte apoptosis induced by chronic alcoholic intoxication in rats

AIM: To investigate the role of hepatocyte apoptosis in the pathogenesis of alcohol-induced liver diseases (ALD) in rats.

METHODS: The rat model of liver injury was induced by combination of drinking and gastric irrigation of ethanol. The morphological changes of the liver were observed by routine HE staining under light microscope. The hepatocyte apoptosis was examined by TUNEL, and the levels of serum alanine aminotransferase (ALT) and aspartate transaminase (AST) were detected by the rate method.

RESULTS: At the end of the 5^th week, the light and moderate steatosis appeared in ethanol-treated rat livers, the proportion of fatty degeneration was 40% (8/20); At the end of the 10^th week, the proportion was increased to 85%(17/20), and the morphological changes of alcoholic hepatitis (AH) were found in 45%(9/20) rats. The serum levels of ALT and AST (nkat/L) in ethanol-treated rats were significantly higher than those of the controls (5 wk: 1 017±267 vs 550±133, P < 0.05; 1 350±333 vs 967±150, P < 0.05; 10 wk: 1 500±267 vs 767±250, P < 0.05; 2 167±533 vs 850±183, P < 0.05), and ALT and AST levels at 10 wk were also higher than those at 5 wk (P < 0.05). The TUNEL indexes (%) in at 5 and 10 wk were 0.33±0.49 and 2.03±1.61 respectively (P < 0.05), and the index at 10 wk was significantly different from that of the controls (0.10±0.21, P < 0.05). Furthermore, the TUNEL index of alcoholic hepatitis was significantly higher than that of alcoholic fatty liver (3.24±1.50% vs 1.12±0.63%, P < 0.05). Both show the significant difference.

CONCLUSION: Chronic and excessive ethanol consumption can cause liver injury in rats. The amount and time of daily ethanol intake is closely related with the degrees of liver injury. Hepatocyte apoptosis may play an important role in the pathogenesis of ALD.

Effects of nuclear factor-kappaB on rat hepatocyte regeneration and apoptosis after 70% portal branch ligation

AIM: To detect the DNA binding activity of nuclear factor-kappaB (NF-кB) in rat hepatocyte and to investigate the effects of NF-кB on rat hepatocyte regeneration and apoptosis after 70% portal branch ligation.

METHODS: Sixty Wistar rats were randomly divided into control group and portal branch ligation group. The animals were killed 12 h, 1, 2, 3, 7, and 14 d after surgery to determine the contents of plasma ALT. Hepatocytes were isolated and nuclear protein was extracted. DNA binding activity of NF-κB was measured by EMSA. Hepatocyte regeneration and apoptosis were observed under microscope by TUNEL staining. The ultrastructural changes of liver were observed under electron microscope.

RESULTS: Seventy percent portal branch ligation produced atrophy of the ligated lobes and the perfused lobes underwent compensatory regeneration, the total liver weight and plasma ALT levels were maintained at the level of sham-operated animals throughout the experiment. After 2 d of portal branch ligation, DNA binding activity of NF-кB in hepatocyte increased and reached its peak, the number of apoptotic hepatocyte in the ligated lobes and the number of mitotic hepatocyte in the perfused lobes also reached their peak. Typical apoptotic changes and evident fibrotic changes in the ligated lobes were observed under electron microscope.

CONCLUSION: After 70% portal branch ligation, DNA binding activity of NF-кB in hepatocyte is significantly increased and NF-кB plays an important role in hepatocyte regeneration and apoptosis.

Effect of bombesin and neurotensin on gut barrier function in partially hepatectomized rats

AIM: To investigate the effect of regulatory peptides bombesin (BBS) and neurotensin (NT) on intestinal barrier function in partially hepatectomized rats.

METHODS: Ninety male Wistar rats were randomly divided into five groups: I (n = 10): controls, II (n = 20): sham operated, III (n = 20): partial hepatectomy 70% (PHx), IV (n = 20): PHx+BBS (30 μg/kg/d), V (n = 20): PHx+NT (300 μg/kg/d). Groups IV and V were treated for 8 days before PHx and 48 h post surgery. At the end of the experiment, on day 10, intestinal barrier function was assessed by measuring endotoxin concentrations in portal and aortic blood. Tissue sections of the terminal ileum were examined histologically and villus density, mucosal thickness, mitotic activity and apoptosis in crypts were assessed. In addition, ileal mucosa was analyzed for DNA and protein content and microbiological analysis was performed in cecal contents. To estimate intestinal oxidative stress, lipid peroxidation was determined on tissue homogenates from terminal ileum.

RESULTS: BBS or NT administration significantly reduced portal and systemic endotoxemia observed 48 h after partial hepatectomy. In hepatectomized rats (group III), a trend towards induction of mucosal atrophy was observed, demonstrated by the reduction of villus density, mucosal thickness, protein content and significant reduction of DNA, while these alterations were reversed by regulatory peptides administration. This trophic effect of BBS and NT was accompanied by induction of mitoses above control levels and a significant reduction of apoptosis in intestinal crypts. Intestinal lipid peroxidation was found significantly lower in PHx group and regulatory peptides exerted an antioxidant action, further decreasing this parameter of oxidative stress. The bacterial population of E. coli and aerobic Gram (+) cocci was increased in cecal content of hepatectomized rats, while this parameter was not affected by the administration of BBS or NT.

CONCLUSION: Gut regulatory peptides BBS and NT improve intestinal barrier function and reduce endotoxemia in experimental partial hepatectomy. This effect is, at least in part, mediated by their trophic, antiapoptotic, mitogenic, and antioxidant effect on the intestinal epithelium. This observation might be of potential value in patients undergoing liver resection.

Dual effects of 8-Br-cAMP on differentiation and apoptosis of human esophageal cancer cell line Eca-109

AIM: To investigate the effects of 8-Br-cAMP on differentiation and apoptosis of human esophageal cancer cell line Eca-109, and the related gene expression.

METHODS: The cultured Eca-109 cells were divided into four groups: E1 group (co-cultured with 8-Br-cAMP for 24 h); E2 group (co-cultured with 8-Br-cAMP for 48 h); C1 group (treated without 8-Br-cAMP for 24 h); and C2 group (treated without 8-Br-cAMP for 48 h). The same concentration of cell suspension of each group was dropped separately onto the slides and nitrocellulose membranes (NCM). The biotin-labeled cDNA probes for c-myc, wild-type (wt) p53, bcl-2 and iNOS were prepared for in situ hybridization. The expressions of epidermal growth factor receptor (EGFR), p38 kinase, FAS, FasL and caspase-3 were detected using immunocytochemistry, and the NOS activity and the ratio of differentiated cells/proliferating cells were examined by cytochemistry. Immunocytochemistry, cytochemistry, and in situ hybridization were separately carried out on both slides and NCM specimens for each group. In addition, TUNEL was used to detect the cell apoptosis rate in each group.

RESULTS: The apoptotic rate of E2 group was significantly higher compared to E1 group, while there was no difference in the ratio of differentiated cells/proliferating cells between E1 and E2 groups. The signals of wt p53 and iNOS were markedly stronger, while the signals of c-myc and EGFR were obviously weaker in E1 group than those in C1 group (P<0.05). Moreover, the signals of wt p53, iNOS, p38 kinase, caspase-3 and NOS activity were significantly stronger, whereas, the signals of bcl-2, c-myc and Fas/FasL were markedly weaker in E2 group than those in C2 group (P<0.05).

CONCLUSION: The differentiation and apoptosis of human esophageal cancer cell Eca-109 can be induced after 24- and 48-h treatment with 8-Br-cAMP, respectively. Upregulation of wt p53, iNOS and downregulation of c-myc may be associated with differentiation and apoptosis of Eca-109 cells. Furthermore, upregulation of FasL, p38 kinase and caspase-3 as well as downregulation of bcl-2, and Fas may be involved in the apoptosis of Eca-109 cells.

Bile salts inhibit growth and induce apoptosis of culture human normal esophageal mucosal epithelial cells

AIM: To investigate the effect of six bile salts: glycocholate (GC), glycochenodeoxycholate (GCDC), glycodeoxycholate (GDC), taurocholate (TC), taurochenodeoxycholate (TCDC), taurodeoxycholate (TDC), and their mixture on cultured human normal esophageal mucosal epithelial cells.

METHODS: Human normal esophageal mucosal epithelial cells were cultured with serum-free keratinocyte medium. 3-[4,5-Dimethylthiaolyl]-2,5-diphenyl-tetrazolium bromide assay was applied to the detection of cell proliferation. Apoptotic morphology was observed by phase-contrast video microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Sub-G1 DNA fragmentations and early apoptotic cells were assayed by flow cytometry (FCM) with propidium iodide (PI) staining and annexin V-FITC conjugated with PI staining. Apoptotic DNA ladders on agarose gel electrophoresis were observed.

RESULTS: Except for GC, GCDC, GDC, TC, TCDC, TDC and their mixture could initiate growth inhibition of esophageal mucosal epithelial cells in a dose- and time-dependent manner. TUNEL and FCM assays demonstrated that the bile salts at 500 μmol/L and their mixture at 1 500 μmol/L induced apoptosis except for GC. The percentage of sub-G1 detected by FCM with PI staining was 83.5% in cells treated with 500 μmol/L TC for 2 h, and 19.8%, 20.4%, 25.6%, 13.5%, and 75.8% in cells treated with 500 μmol/L GCDC, TCDC, GDC, TDC, and 1 500 μmol/L mixture for 24 h, respectively, which were higher than that of the control (1.5%). The percentage was 1.4% in cells with 500 μmol/L GC for 24 h. DNA ladders on agarose gel electrophoresis were seen in cells treated with 500 μmol/L TC for 2 h and 1 500 μmol/L mixture for 24 h.

CONCLUSION: All GCDC, GDC, TC, TCDC, TDC and their mixture can inhibit growth and induce apoptosis of cultured human normal esophageal mucosal epithelial cells, but GC is well tolerated by the cells.

Genistein inhibits invasive potential of human hepatocellular carcinoma by altering cell cycle, apoptosis, and angiogenesis

AIM: To study the in vitro and in vivo inhibitory effects of genistein on invasive potential of Bel 7402 hepatocellular carcinoma (HCC) cells and to explore the underlying mechanism.

METHODS: Bel 7402 HCC cells were exposed to genistein. The invasive activity of tumor cells was assayed in transwell cell culture chamber. p125^FAK expression and cell cycle were evaluated by a functional assay. Cell apoptosis analysis was performed with TUNEL method. In addition, bilateral subrenal capsule xenograft transplantation of HCC was performed in 10 nude mice. Genistein was injected and the invasion of HCC into the renal parenchyma was observed. Microvessels with immunohistochemical staining were detected.

RESULTS: Genistein significantly inhibited the growth of Bel 7402 cells, the inhibitory rate of tumor cells was 26–42%. The invasive potential of Bel 7402 cells in vitro was significantly inhibited, the inhibitory rate was 11–28%. Genistein caused G2/M cell cycle arrest, S phase decreased significantly. The occurrence of apoptosis in genistein group increased significantly. The expression of p125^FAK in 5 μg/mL genistein group (15.26±0.16%) and 10 μg/mL genistein group (12.89±0.36%) was significantly lower than that in the control group (19.75±1.12%, P<0.05). Tumor growth in genistein-treated nude mice was significantly retarded in comparison to control mice, the inhibitory rate of tumor growth was about 20%. Genistein also significantly inhibited the invasion of Bel 7402 cells into the renal parenchyma of nude mice with xenograft transplant. The positive unit value of microvessels in genistein-treated group (10.422 ± 0.807) was significantly lower than that in control group (22.330 ± 5.696, P < 0.01).

CONCLUSION: Genistein can effectively inhibit the invasive potential of Bel 7402 HCC cells by altering cell cycle, apoptosis and angiogenesis, inhibition of focal adhesion kinase may play a significant role in this process.

Pattern of apoptosis by NS398, a selective COX-2 inhibitor, in hepatocellular carcinoma cell lines

PURPOSE

NS398, a selective COX-2 inhibitor, is known to inhibit the growth of COX-2 expressing hepatocellular carcinoma cells. The present study investigated whether the cytotoxic effect of NS398 was COX-2 dependent and whether caspases were involved in NS398-induced apoptosis in hepatocellular carcinoma cells.

MATERIALS AND METHODS

The expressions of COX-2 in SNU 423 and SNU 449 hepatocellular carcinoma cell lines were examined using RT-PCR and Western blot. The cytotoxic effect of NS398 was measured using MTT in the presence or absence of caspase inhibitors. The distribution of the cell cycle and extent of apoptosis were analyzed using flow cytometry and a Cell Death Elisa kit, respectively.

RESULTS

The expression of COX-2 was observed in SNU423 cells, but not in SNU 449 cells. NS398 treatment resulted in both dose-and time-dependent growth inhibitions, with increases in apoptotic cells in both cell lines. Treatment with the pan-caspase inhibitor, z-VAD- fmk, or the caspase-3 inhibitor, Ac-DMQD-CHO, showed no attenuation of the cytotoxic effect of NS398 in either cell line.

CONCLUSION

This study demonstrated that the cytotoxic effect of NS398 was independent of COX-2 expression. Caspases were also shown not to be involved in NS398-induced apoptosis in either SNU 423 or SNU 449 Korean HCC cell lines. Our data suggests the feasibility of preventing hepatocellular carcinoma with the use of COX-2 inhibitors needs to be carefully evaluated.

Tetraarsenic oxide-mediated apoptosis in a cervical cancer cell line, SiHa

PURPOSE

Diarsenic oxide, As(2)O(3), has been reported to be effective in treating acute leukemia, and induce apoptosis in many tumor cells. In this study, the ability of a novel arsenical compound, As(4)O(6) (tetraarsenic oxide), along with As(2)O(3), for its ability to induce cell growth inhibition, as well as apoptosis, in human cervical cancer cells, SiHa cells, were evaluated in vitro.

MATERIALS AND METHODS

To examine the levels of apoptosis, SiHa cells were given two sensitive doses, 0.5 and 1 microM, of arsenical compounds, and a DNA fragmentation assay and FACS analysis were then conducted. In addition, a Western blotting assay was performed to identify target molecules for apoptosis.

RESULTS

Both As(2)O(3) and As(4)O(6) induced dosedependent inhibition of SiHa cell proliferation. In particular, As(4)O(6) was more effective at suppressing SiHa cell growth than As(2)O(3). In parallel with the inhibition of cell proliferation, As(4)O(6) caused a significantly greater increase in the sub-G1 cell population than As(2)O(3), as determined by propidium iodide DNA staining. This was confirmed by a DNA fragmentation assay and annexin V staining. The Western blotting analysis also showed that the expression of proliferating cell nuclear antigen (PCNA) was suppressed to a significantly greater extent by As(4)O(6) than As(2)O(3) at a dose of 0.5 microM. However, the apoptosis-related protein, Bax, was expressed to a significantly greater extent due to As(4)O(6) than As(2)O(3).

CONCLUSION

Taken together, these findings suggest that a novel arsenic compound, As(4)O(6), possesses more potent anti-proliferative effects on human cervical cancer cells, with the induction of apoptosis also, at least via the activation of Bax protein in vitro.