Apoptotic activities in soft tissue sarcoma: immunohistochemical study and their association with tumour characteristics

BACKGROUND

Many studies on the role of apoptosis in cancer development and management have been undertaken. Apoptotic activity depends partly on the balance between anti-apoptotic (Bcl-2) and pro-apoptotic (Bax) activities. This study compared Bcl-2 and Bax expression in the tumour cells and endothelial cells of tumour blood vessels in soft tissue sarcoma, and examined the association of these with tumour characteristics.

METHODS

A cross sectional (retrospective) study was conducted on 101 cases of various types of soft tissue sarcoma tumour cells and endothelial cells of tumour blood vessels. The immunohistochemical expressions of Bcl-2 and Bax were compared by correlating them according to site, size, depth, tumour margin, lymph node involvement, and histological type.

RESULTS

Higher Bax than Bcl-2 expression in tumour cells was observed, although the difference was not statistically significant. There was a significant direct association between Bcl-2 and Bax in tumour cells with endothelial cells. Among tumour characteristics, the only significant correlation was that of the Bcl-2 expression in tumour cells with tumour histological subtypes (synovial sarcoma and leiomyosarcoma).

CONCLUSION

The findings in this study support the role of endothelial cells in the survival and regression of tumour cells in tumour genesis. Therefore, inhibition of endothelial cell survival and activation, or induction of tumour cell apoptosis offers a promising prospect for tumour management.

Expressions of apoptosis-related proteins in rats with focal cerebral ischemia after Angong Niuhuang sticker point application

In this study, we extracted and purified components in the Angong Niuhuang pill. Then we applied transdermal enhancers to Angong Niuhuang stickers by modern technology. The Angong Niuhuang sticker includes extracts from curcuma, berberine hydrochloride, baicalin, geniposide, borneol, and musk. Angong Niuhuang stickers at different point application doses (1.35, 2.7, and 5.4 g/kg) were administered to Dazhui (DU14), Qihai (RN6) and Mingmen (DU4). Rats in the different dose point application and acupuncture groups were continuously administered for 7 days. Then a middle cerebral artery occlusion model was prepared for simulating human cerebral ischemia. Twelve hours later, expressions of Bcl-2, Bax and p53 protein in hippocampal CA1 were detected with immunohistochemistry. The expression level of Bcl-2, an anti-apoptotic protein, significantly increased in the high-, medium- and low-dose point application groups and the acupuncture group, while the expression of the pro-apoptotic proteins, Bax and p53, significantly decreased compared with the middle cerebral artery occlusion rats; and the Bcl-2/Bax ratio was significantly increased. The difference was noticeable for the high-dose point application group, which showed statistical difference compared with the low-dose point application group and the acupuncture group. Our experimental findings indicate that point application with Angong Niuhuang stickers promotes the expression of Bcl-2, and inhibits the expressions of Bax and p53 in the hippocampal CA1 area of rats after focal cerebral ischemia. Thus, point application of Angong Niuhang stickers protects brain tissues from cerebral ischemia.

Implications of bax, fas, and p53 in the pathogenesis of early-stage mycosis fungoides and alterations in expression following photochemotherapy

Background:

The underlying molecular basis of mycosis fungoides (MF) has not yet been clarified. However, defects in apoptosis may contribute to its pathogenesis.

Aim:

We investigated the expression of Bax, Fas, and p53 in early-stage MF patients and any alterations in expression following photochemotherapy.

Materials and Methods:

Bax, Fas, and p53 expressions were studied by immunohistochemistry in both keratinocytes and lymphocytes on paraffin-embedded skin specimens from 27 early-stage MF patients.

Results:

Bax, Fas, and p53 staining was shown in the lymphocytes in 0/27, 26/27, and 11/27 patients at the time of diagnosis, whereas these ratios were 0/27, 9/27, and 0/27, respectively, after psoralen plus ultraviolet A (PUVA) treatment. The decrease in p53 and Fas expression in the lymphocytes was found statistically significant. Bax, Fas, and p53 staining in the keratinocytes was shown in 5/27, 27/27, and 25/27 patients at the time of diagnosis, whereas these ratios were 0/27, 22/27, and 4/27, respectively, after PUVA treatment. The decrease in p53, Fas, and Bax expression in the keratinocytes was found statistically significant.

Conclusion:

Although Bax seems unrelated with early-stage MF, Fas and p53 expression in the lymphocytes may contribute to the understanding of the pathogenesis of this disease.

Bax expression is a candidate prognostic and predictive marker of colorectal cancer

OBJECTIVE

Since the anti-tumor activity of 5-fluorouracil (5-FU) is due to induction of apoptosis, we assessed the value of expression of key apoptotic molecules (Bax, Bcl-2 and p53) in predicting the efficacy of 5-FU therapy for colorectal adenocarcinomas (CRCs).

METHODS

Archival tissues of CRCs from 56 patients who received a complete regimen of 5-FU-based chemotherapy after surgery, and 56 patients matched for age, gender, ethnicity, tumor stage, tumor location, and tumor differentiation who had undergone only surgery (without any pre- or post-surgery therapy), were evaluated for immunophenotypic expression of Bax, Bcl-2, and p53. Also, these CRCs were evaluated for Bax mutations. The predictive capacity or prognostic value of these markers was assessed by estimating overall survival.

RESULTS

The majority of low Bax expressing CRCs have exhibited mutations at the G (8) tract. There was no significant difference in overall survival rates between the categories of surgery alone and 5-FU-treated patients. However, a better survival was observed for patients who received chemotherapy when their CRCs had low Bax/Bcl2 ratio (HR, 1.55; 95% CI: 1.46-31.00). Patients who received surgery alone and whose CRCs lacked Bax expression had 5.33 times higher mortality than those with high Bax expression (95% CI: 1.78-15.94), when controlled for tumor stage and other confounders. Bcl-2 and nuclear p53 accumulation had no predictive value in either patient group.

CONCLUSION

These findings are the first to demonstrate that high Bax expression is a good prognosticator for patients who underwent surgery alone, and that patient with low Bax/Bcl-2 expression ratio benefit from 5-FU-based adjuvant therapies.

Effect of total flavone of Litchi chinensis Sonn on the expression of Bcl-2 and Bax in hepatic fibrosis in rats

AIM: To study the effect of total flavone of Litchi chinensis Sonn (TFL) on liver cell apoptosis in rats with hepatic fibrosis and to explore possible mechanisms involved.

METHODS: Fifty rats were randomly divided into five groups: blank control group, colchicine group, model group, low- and high-dose TFL groups. Hepatic fibrosis was induced in rats by intraperitoneal injection of dimethylnitrosamine. The TFL groups were intragastrically administered with different doses of TFL for 6 wk, while the blank control group and colchicine group were given normal saline and colchicine, respectively. After treatment, liver samples were taken to examine the degree of liver fibrosis by HE and Masson staining and to detect Bcl-2 and Bax expression by immunohistochemistry. Serum ALT and AST levels were also measured.

RESULTS: The expression of Bcl-2 and Bax in the model group was significantly higher than that in the normal group (both P = 0.000). The expression of Bcl-2 was higher and that of Bax was lower in the TFL groups and colchicine group than in the model group (Bcl-2: P = 0.000, 0.047, 0.021; Bax: P = 0.000, 0.014, 0.007), and in the high-dose TFL group than in the low-dose TFL group (P = 0.018, 0.002). Bcl-2 and Bax expression showed no significant difference between the low-dose TFL group and colchicine group (P = 0.726, 0.767). The severity of liver fibrosis was positively correlated with Bax expression (P = 0.000) but negatively with Bcl-2 expression (P = 0.000). Serum levels of ALT and AST were significantly lower in the blank control group, TFL groups and colchicine group than in the model group (all P = 0.000), but showed no significant difference between the low-dose TFL group and colchicine group (P = 0.597, 0.669).

CONCLUSION: TFL can resist hepatic fibrosis and improve liver function possibly by up-regulating Bcl-2 expression and down-regulating Bax expression to inhibit liver cell apoptosis.

Untangling the Roles of Anti-Apoptosis in Regulating Programmed Cell Death using Humanized Yeast Cells

Genetically programmed cell death (PCD) mechanisms, including apoptosis, are important for the survival of metazoans since it allows, among things, the removal of damaged cells that interfere with normal function. Cell death due to PCD is observed in normal processes such as aging and in a number of pathophysiologies including hypoxia (common causes of heart attacks and strokes) and subsequent tissue reperfusion. Conversely, the loss of normal apoptotic responses is associated with the development of tumors. So far, limited success in preventing unwanted PCD has been reported with current therapeutic approaches despite the fact that inhibitors of key apoptotic inducers such as caspases have been developed. Alternative approaches have focused on mimicking anti-apoptotic processes observed in cells displaying increased resistance to apoptotic stimuli. Hormesis and pre-conditioning are commonly observed cellular strategies where sub-lethal levels of pro-apoptotic stimuli lead to increased resistance to higher or lethal levels of stress. Increased expression of anti-apoptotic sequences is a common mechanism mediating these protective effects. The relevance of the latter observation is exemplified by the observation that transgenic mice overexpressing anti-apoptotic genes show significant reductions in tissue damage following ischemia. Thus strategies aimed at increasing the levels of anti-apoptotic proteins, using gene therapy or cell penetrating recombinant proteins are being evaluated as novel therapeutics to decrease cell death following acute periods of cell death inducing stress. In spite of its functional and therapeutic importance, more is known regarding the processes involved in apoptosis than anti-apoptosis. The genetically tractable yeast Saccharomyces cerevisiae has emerged as an exceptional model to study multiple aspects of PCD including the mitochondrial mediated apoptosis observed in metazoans. To increase our knowledge of the process of anti-apoptosis, we screened a human heart cDNA expression library in yeast cells undergoing PCD due to the conditional expression of a mammalian pro-apoptotic Bax cDNA. Analysis of the multiple Bax suppressors identified revealed several previously known as well as a large number of clones representing potential novel anti-apoptotic sequences. The focus of this review is to report on recent achievements in the use of humanized yeast in genetic screens to identify novel stress-induced PCD suppressors, supporting the use of yeast as a unicellular model organism to elucidate anti-apoptotic and cell survival mechanisms.

Oridonin nanosuspension was more effective than free oridonin on G2/M cell cycle arrest and apoptosis in the human pancreatic cancer PANC-1 cell line

Oridonin, a diterpenoid isolated from Rabdosia rubescencs, has been reported to have antitumor effects. However, low solubility has limited its clinical applications. Preparation of drugs in the form of nanosuspensions is an extensively utilized protocol. In this study, we investigated the anticancer activity of oridonin and oridonin nanosuspension on human pancreatic carcinoma PANC-1 cells. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to investigate the effect of oridonin on cell growth. Propidium iodide and Hoechst 33342 staining were used to detect morphologic changes. The percentage of apoptosis and cell cycle progression was determined by flow cytometric method staining with propidium iodide. Annexin V-fluorescein isothiocyanate (FITC)/PI staining was used to evaluate cell apoptosis by flow cytometry. Caspase-3 activity was measured by spectrophotometry. The apoptotic and cell cycle protein expression were determined by Western blot analysis. Both oridonin and oridonin nanosuspension induced apoptosis and G₂/M phase cell cycle arrest, and the latter had a more significant cytotoxic effect. The ratio of Bcl-2/Bax protein expression was decreased and caspase- 3 activity was stimulated. The expression of cyclin B1 and p-cdc2 (T161) was suppressed. Our results showed that oridonin nanosuspension was more effective than free oridonin on G₂/M cell cycle arrest and apoptosis in the human pancreatic cancer PANC-1 cell line.

Effect of endogenous hydrogen sulfide on apoptosis of cirrhosis rat liver cells

AIM: To explore the effect of a metabolic inhibitor of hydrogen sulfide on apoptosis of liver cells in rats with cirrhosis, and to explore the mechanism underlying the protective effect of hydrogen sulfide against cirrhosis.

METHODS: Forty female SD rats were randomly divided into four groups: normal controls (group N), normal controls treated with propargylglycine (PPG) (group P), cirrhotic rats (group H), and cirrhotic rats treated with PPG (group PH). Rats in groups H and PH were subjected to induction of cirrhosis by injecting carbon tetrachloride (CCl4). Rats in groups P and PH were injected with PPG (30 mg/kg·d) to decrease the content of hydrogen sulfide in the liver. Rats in groups N and H were injected with equal volume of normal saline. The distribution of cystathionine-γ-lyase (CSE) in the liver was examined by immunohistochemistry. The apoptosis of liver cells was detected by TUNEL assay. The expression of Bax and Bcl-2 in liver cells was detected by Western blot.

RESULTS: Compared to group N, apoptosis index (AI) significantly increased (P = 0.000) and expression of Bax was significantly up-regulated (P = 0.001) in group H. Compared to group H, AI and expression of Bax significantly increased (P = 0.000, 0.021), and CSE decreased (P = 0.029) in group PH.

CONCLUSION: Inhibition of hydrogen sulfide promotes apoptosis of liver cells in rats with cirrhosis possibly by regulating the expression of Bax.

Effects of minocycline on apoptosis and angiogenesis-related protein expression in a rat model of intracerebral hemorrhage

In the present study, a rat model of non-traumatic intracerebral hemorrhage was established by type IV collagenase injection into the right globus pallidus. Bax and Bcl-2 expression in tissues surrounding hematomas was significantly increased within 14 days after injury, and it then gradually decreased. Vascular endothelial growth factor, Flk-1 and Flt-1 mRNA expression gradually increased over time. After intraperitoneal injection with minocycline, Bax expression was decreased 1 day after intracerebral hemorrhage. Flk-1 and Flt-1 mRNA expression was decreased after minocycline injection, but Bcl-2 expression was increased, and vascular endothelial growth factor mRNA expression was decreased between 4-14 days. These results indicated that protective effects of minocycline on nerve tissues were associated with increased Bcl-2 expression and decreased Bax expression in the early stage after intracerebral hemorrhage. In the late stage, minocycline downregulated vascular endothelial growth factor and its receptor expression to inhibit brain tissue self-repair.

Neuroprotective effects of total saponins from Rubus parvifolius L. on cerebral ischemia/reperfusion injury in rats

This study examines the neuroprotective effects and mechanisms of action of total saponins from Rubus parvifolius L. (TSRP) on focal cerebral ischemia and reperfusion injury in rats. Focal cerebral ischemia and reperfusion injury was performed in rats using the suture method. The results indicate that intragastric injection of TSRP, at 5, 10 and 20 mg/kg, could decrease neurological impairment, reduce cerebral infarct volume, diminish pathological changes, and significantly inhibit the apoptosis of neurons surrounding the ischemic area. In addition, TSRP upregulated the expression of the anti-apoptotic factor Bcl-2, at the protein and mRNA levels, and it downregulated the expression of the pro-apoptotic factor Bax, at the protein and mRNA levels. These findings indicate that TSRP protects against cerebral ischemia/reperfusion injury, and that it may do so by regulating the expression of Bcl-2 and Bax.

Evaluation of Bcl-2 Family Gene Expression in Hippocampus of 3, 4-methylenedioxymethamphetamine Treated Rats

OBJECTIVE

3,4-methylenedioxymethamphetamine (MDMA) is an illicit, recreational drug that causes cellular death and neurotoxicity. This study evaluates the effects of different doses of MDMA on the expression of apoptosis-related proteins and genes in the hippocampus of adult rats.

MATERIALS AND METHODS

In this expremental study,a total of 20 male Sprague Dawley rats (200-250 g ) were treated with MDMA (0, 5, 10, 20 mg/kg i.p. twice daily) for 7 days. Seven days after the last administration of MDMA, the rats were killed. Bax and Bcl-2 genes in addition to protein expressions were detected by western blot and reverse transcriptionpolymerase chain reaction (RT-PCR).Results were analyzed using one-way ANOVA and p≤0.05 was considered statistically significant.

RESULTS

Our results showed that MDMA caused dose dependent up-regulation of Bax and down-regulation of Bcl-2 in the hippocampus. There was a significant alteration in bcl-2 and bax genes density.

CONCLUSION

Changes in apoptosis-related proteins and respective genes relating to Bax and Bcl-2 might be involved in the molecular mechanism of MDMA-induced apoptosis.

Pro- and antiapoptotic markers in upper tract urothelial carcinoma associated with Balkan endemic nephropathy

The role of aristolochic acid in the etiology of Balkan endemic nephropathy (BEN) and associated upper-tract urothelial carcinoma (UTUC) has been recently confirmed. The aim of this study was to determine apoptosis-related marker(s) specific for BEN-associated UTUC. Present investigation included 105 patients with UTUC, 44 from BEN region and 61 control tumors. Altered expression of Survivin was more often present in BEN UTUC with high grade and solid growth (P < 0.005; P < 0.05) than in control tumors. Significantly lower expression of proapoptotic marker Bax was found in BEN tumors with high grade, high stage, necrosis, and without metaplastic change (P < 0.05; 0.05; 0.05; 0.05) compared to control tumors with the same features. Group (BEN-related/control), stage, growth pattern, and caspase 3 activity were significantly associated with the expression of Bax (P = 0.002, 0.034, 0.047, 0.028, resp.,). This investigation identifies Bax as specific marker of BEN-associated UTUC. Decrease of pro-apoptotic protein Bax together with alteration of Survivin may be indicative for specific disturbances of intrinsic apoptotic pathway in UTUC arising in endemic areas.

Antitumor activity of active components alignment isolated from Stellera chamaejasme L. in nude mice bearing subcutaneous BEL-7402 hepatoma

AIM: To assess the antitumor activity of the effective extracts of S. chamaejasme L. (ScL) in a murine model of hepatocellular carcinoma and to explore the possible mechanisms involved.

METHODS: A tumor transplantation model was generated in nude mice to study the antitumor activity of the active components alignment Zp1111 in vivo. Immunohistochemistry (IHC) was employed to investigate the expression of Bcl-2 and Bax in tumor tissue.

RESULTS: Zp1111 exhibited strong antitumor activity in BEL7402-bearing nude mice, with the relative tumor proliferation rate (T/C) less than 60% at a dose of 187.5 or 250 mg/kg. Treatment with Zp1111 up-regulated Bax expression and slightly down-regulated Bcl-2 expression in tumor tissue.

CONCLUSION: The active components alignment of ScL significantly reduces BEL-7402 proliferation in a dose-dependent manner in vivo possibly by up-regulating Bax expression to induce cell apoptosis.

Effect of Lecithin on d-Galactosamine Induced Hepatotoxicity Through Mitochondrial Pathway Involving Bcl-2 and Bax

Twenty four Wistar strain albino rats were used for the investigations. Lecithin 50 and 100 mg/kg b wt was administered for 1 week by oral route. Liver damage was induced by intra peritoneal administration of 400 mg/kg b wt d-galactosamine on the last day. At the end of the study animals were sacrificed and liver enzyme levels, histopathology, mitochondrial integrity, expression of p53, Bax and Bcl-2 mRNA levels were studied. Increases in the liver enzyme levels by d-GalN were significantly inhibited by pretreatment with lecithin. Histopathological observation further confirmed the hepatoprotective effect of lecithin. In addition, the disruption of mitochondrial membrane, up regulation of Bax and down regulation of Bcl-2 mRNA levels in the liver of d-GalN intoxicated rats were effectively prevented by pretreatment with lecithin. The results of the present study validate our conviction that d-GalN causes hepatic damage via mitochondrial pathway involving Bax and Bcl-2.

Network modeling of CDF treated pancreatic cancer cells reveals a novel c-myc-p73 dependent apoptotic mechanism

Systems biology and molecular network modeling are important tools that are finding application in anti-cancer drug discovery. These technologies can be utilized to map and evaluate the entire set of pathways modulated by drugs in cancer cells without loosing key details. Such integrated approaches are especially useful in understanding the mechanism of action of agents that do not have a defined target. Our novel compound CDF (a synthetic analogue of curcumin), is one such multi-targeted agent with proven anti-cancer activity in vitro and in vivo. However, its mechanism of action is not fully understood, and thus a thorough analysis of key pathways targeted by CDF would be important for developing targeted and tailored therapy in the future. Applying Ingenuity Pathway Analysis (IPA), we have mapped the pathways altered by CDF treatment of BxPC-3 pancreatic cancer (PC) cells. Illumina HT-12 microar-rays were performed on RNA extracted from CDF treated cells. IPA analysis of gene expression at early time point (24 hrs) revealed deregulation of genes in the c-Myc hub. Western blot analysis validated the activation of c-Myc, p73 and its downstream pro-apoptotic effector Bax with simultaneous down-regulation of Bcl-2 in two distinct pancreatic cancer cell lines (BxPC-3 and Colo-357). In order to further delineate the role of c-Myc in inducing apoptosis, siRNA silencing technology was used. As expected, c-Myc siRNA knockdown resulted in abrogation of the growth inhibitory and apoptotic potential of CDF. In conclusion, our results demonstrate a novel c-Myc driven apoptotic network activated by CDF in PC cells that is independent of wild-type p53, and thus warrants further investigation on the clinical utility of CDF.

Curcumin Induces Apoptosis in EJ Bladder Cancer Cells via Modulating C-Myc and PI3K/Akt Signaling Pathway

Background

Cancer chemopreventive agent curcumin has been shown to possess cell growth inhibition and apoptosis induction properties in several types of cancer. However, the detailed molecular mechanisms of the compound remain far from clear in EJ bladder cancer cells.

Methods

The effect of curcumin on EJ cell growth and apoptosis was detected by MTT assays and flow cytometry. The phosphorylation levels of PTEN, PDK1, Akt, GSK-3β, c-Raf, and Bad and the expression levels of c-myc, Bax, Bcl-2, caspase-9, caspase-7, caspase-3, and PARP following curcumin administration were examined by immunoblots.

Results

Curcumin suppressed the growth of EJ cells in a time and concentration dependent manner. Immunoblot showed that curcumin increased expression levels of c-myc and inhibited the activation of PI3K/Akt pathway in a time-dependent manner in EJ cells. Activation of PTEN, GSK-3β, c-Raf, caspase-9, caspase-7, and caspase-3, cleavage of PARP, upregulation of Bad and Bax, and downregulation of Akt and Bcl-2 were also found in curcumin-treated EJ cells.

Conclusions

These findings establish a mechanistic linkup or interaction between c-myc, Bax, Bad, Bcl-2, caspase cascades, PI3K/Akt pathway and curcumin- induced apoptosis of EJ cells, suggesting that c-myc and PI3K/Akt signaling pathway play important roles in curcumin-induced apoptosis of EJ bladder cancer cells.

Differential expression of Bcl-2 and Bax during gastric ischemia-reperfusion of rats

AIM: To investigate expression of Bcl-2 and Bax in gastric ischemia-reperfusion (GI-R) and involvement of extracellular signal-regulated kinase (ERK) 1/2 activation.

METHODS: The GI-R model was established by ligature of the celiac artery for 30 min and reperfusion in Sprague-Dawley rats. Rats were assigned to groups in accordance with their evaluation period: control, 0, 0.5, 1, 3, 6, 24, 48, and 72 h. Expression and distribution of Bcl-2 and Bax proteins were analyzed by immunohistochemistry and western blotting in gastric tissue samples after sacrifice.

RESULTS: Compared with controls, the percentage of positive cells and protein levels of Bcl-2 decreased in the early phases of reperfusion, reached its minimum at 1 h (P < 0.05); it then increased, reaching its peak at 24 h of reperfusion (P < 0.05). The pattern of Bax expression was opposite to that of Bcl-2. Bax expression increased after reperfusion, with its peak at 1 h of reperfusion (P < 0.05), and then it decreased gradually to a minimum at 24 h after reperfusion (P < 0.05). On the other hand, inhibition of activation of ERK1/2 induced by PD98059, a specific upstream MEK inhibitor, had significant effects on Bcl-2 and Bax in GI-R. Compared with GI-R treatment only at 3 h of reperfusion, PD98059 reduced the number of Bcl-2 positive cells (0.58% of R3h group, P < 0.05) and Bcl-2 protein level (74% of R3h group, P < 0.05) but increased the number of Bax-positive cells (1.33-fold vs R3h group, P < 0.05) and Bax protein level (1.35-fold of R3h group, P < 0.05).

CONCLUSION: These results indicated that the Bcl-2 and Bax played a pivotal role in the gastric mucosal I-R injury and repair by activation of ERK1/2.

Effects of plumbagin on apoptosis and expression of apoptosis-related proteins in human hepatic stellate cells

AIM: To investigate the effects of plumbagin on leptin-induced apoptosis and expression of apoptosis-related protein in human hepatic satellite cells (HSC-LX2) and to explore the anti-fibrotic mechanism of plumbagin.

METHODS: After HSC-LX2 cells were cultured in vitro, stimulated with leptin for 24 h, and treated with different concentrations of plumbagin for 24 h, cell apoptosis was detected by flow cytometry; cell ultrastructure was observed by transmission electron microscopy; and the protein expression of P53, Bax, and Bcl-2 was determined by immunocytochemistry.

RESULTS: HSC-LX2 cells were divided into 6 groups: untreated cells (blank control group), those treated with 100 μg/L leptin (leptin control group), those treated with both leptin and colchicin (colchicin group), those treated with both leptin and 2, 8 or 16 μmol/L plumbagin (2, 8, 16 μmol/L plumbagin group). The apoptosis rate of HSC-LX2 cells was significantly increased in plumbagin groups. The apoptosis rates of cells treated with 8 or 16 µmol/L plumbagin or colchicine were significantly higher than those of the blank control group and leptin group (5.21% ± 0.41%, 8.10% ± 0.63%, 10.1% ± 1.08% vs 1.40% ± 0.13%, 2.85% ± 0.21%, all P < 0.01). Transmission electron microscopy revealed varying degrees of apoptosis in the leptin group or plumbagin groups. Immunocytochemistry analysis showed that the protein expression levels of P53 and Bax were higher and that of Bcl-2 was lower in plumbagin groups than in the leptin group (Bax: 85.24 ± 1.08, 86.35 ± 1.12, 91.13 ± 1.13 vs 56.63 ± 0.94; P53: 25.32 ± 0.6, 38.14 ± 0.71, 41.19 ± 0.72 vs 19.25 ± 0.46; Bcl-2: 32.12 ± 0.43, 27.71 ± 0.38, 21.46 ± 0.46 vs 44.51 ± 0.56, all P < 0.05 or 0.01).

CONCLUSION: Plumbagin can significantly accelerate leptin-induced apoptosis of HSC-LX2 cells possibly by up-regulating P53 and Bax expression and down-regulating Bcl-2 expression.

Expression of ErbB4 in the apoptotic neurons of Alzheimer's disease brain

Neuregulin-1 (NRG1) signaling participates in the synaptic plasticity, maintenance or regulation of adult brain. Although ErbB4, a key NRG1 receptor, is expressed in multiple regions in the adult animal brain, little is known about its localization in Alzheimer's disease (AD) brains. We previously reported that ErbB4 immunoreactivity showed regional difference in the hippocampus of age-matched control. In the present paper, immunohistochemical characterization of the distribution of ErbB4 receptor in the hippocampus relative to pathology staging were performed in age-matched control (Braak stage 0, n=6) and AD (Braak stage I/V, n=10). Here, we found that ErbB4 immunoreactivity was significantly increased in apoptotic hippocampal pyramidal neurons in the brains of AD patients, compared to those of age-matched control subjects. In AD brains, ErbB4 immunoreactivity was demonstrated to colocalize with the apoptotic signal Bax in apoptotic hippocampal pyramidal neurons. These results suggest that up-regulation of ErbB4 immunoreactivity in apoptotic neuron may involve in the progression of pathology of AD.

The neuroprotective effect of recombinant human erythropoietin via an antiapoptotic mechanism on hypoxic-ischemic brain injury in neonatal rats

PURPOSE

The neuroprotective effects of erythropoietin (EPO) have been recently shown in many animal models of brain injury, including hypoxic-ischemic (HI) encephalopathy, trauma, and excitotoxicity; however, limited data are available for such effects during the neonatal periods. Therefore, we investigated whether recombinant human EPO (rHuEPO) can protect against perinatal HI brain injury via an antiapoptotic mechanism.

METHODS

The left carotid artery was ligated in 7-day-old Sprague-Dawley (SD) rat pups (in vivo model). The animals were divided into 6 groups: normoxia control (NC), normoxia sham-operated (NS), hypoxia only (H), hypoxia+vehicle (HV), hypoxia+rHuEPO before a hypoxic insult (HE-B), and hypoxia+rHuEPO after a hypoxic insult (HE-A). Embryonic cortical neuronal cell culture of SD rats at 18 days gestation (in vitro model) was performed. The cultured cells were divided into 5 groups: normoxia (N), hypoxia (H), and 1, 10, and 100 IU/mL rHuEPO-treated groups.

RESULTS

In the in vivo model, Bcl-2 expressions in the H and HV groups were lower than those in the NC and NS groups, whereas those in the HE-A and HE-B groups were greater than those of the H and HV groups. The expressions of Bax and caspase-3 and the ratio of Bax/Bcl-2 were in contrast to those of Bcl-2. In the in vitro model, the patterns of Bcl-2, Bax, and caspase-3 expression and Bax/Bcl-2 ratio were similar to the results obtained in the in vivo model.

CONCLUSION

rHuEPO exerts neuroprotective effect against perinatal HI brain injury via an antiapoptotic mechanism.

Induction of hypoxia-inducible factor-1α inhibits drug-induced apoptosis in the human leukemic cell line HL-60

BACKGROUND

Leukemic cells originate from hypoxic bone marrow, which protects them from anti-cancer drugs. Although many factors that cause drug resistance in leukemic cells have been studied, the effect of hypoxia on drug-induced apoptosis is still poorly understood.

METHODS

In this study, we examined the effect of hypoxia on anti-leukemic drug resistance in leukemic cell lines treated with cobalt chloride (CoCl(2)), a hypoxia-mimetic agent. Cellular proliferation was evaluated using the methyl thiazolyl tetrazolium (MTT) assay. Flow cytometry analysis and western blots were performed to investigate apoptosis-related proteins.

RESULTS

Unlike its previously known apoptotic effect, the expression of HIF-1α increased the survival rate of human promyelocytic leukemia HL-60 cells when these cells were exposed to anti-leukemic drugs; these effects were mediated by heat-shock protein HSP70 and the pro-apoptotic protein Bax.

CONCLUSION

These findings may provide new insights for understanding the mechanisms underlying hypoxia and for designing new therapeutic strategies for acute myeloid leukemia.

Protective Role of Catechin on d-Galactosamine Induced Hepatotoxicity Through a p53 Dependent Pathway

Objective of this study was to obtain a better understanding of the mechanism responsible for the d-galactosamine (d-GalN) induced hepatotoxicity and to study the effect of catechin against d-GalN induced hepatotoxicity. Catechin 50 and 100 mg/kg b.wt was administered for 1 week by oral route. Liver damage was induced by intra-peritoneal administration of 400 mg/kg b.wt d-galactosamine on the last day of catechin treatment. At the end of treatment all animals were killed and liver enzyme levels were estimated. Dissected hepatic samples were used for histopathology, RNA isolation, expression studies of Bax, Bcl-2 and p53 mRNA levels and mitochondrial membrane potential studies. We found that increases in the liver enzyme activity and decrease in antioxidant enzyme activity by d-GalN were significantly restricted by oral pretreatment with catechin. Disruption of mitochondrial membrane potential, up regulation of p53, Bax and down regulation of Bcl-2 mRNA levels in the liver of d-GalN intoxicated rats were effectively prevented by pretreatment with catechin.

Antitumor effect of matrine in human hepatoma G2 cells by inducing apoptosis and autophagy

AIM: To study the antitumor effect of matrine in human hepatoma G2 (HepG2) cells and its molecular mechanism involved in antineoplastic activities.

METHODS: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect viability of HepG2 cells. The effect of matrine on cell cycle was detected by flow cytometry. Annexin-V-FITC/PI double staining assay was used to detect cellular apoptosis. Cellular morphological changes were observed under an inverted phase contrast microscope. Transmission electron microscopy was performed to further examine ultrastructural structure of the cells treated with matrine. Monodansylcadaverine (MDC) staining was used to detect autophagy. Whether autophagy is blocked by 3-methyladenine (3-MA), an autophagy inhibitor, was evaluated. Expression levels of Bax and Beclin 1 in HepG2 cells were measured by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS: Matrine significantly inhibited the proliferation of HepG2 cells in a dose- and time-dependent manner, and induced G1-phase cell cycle arrest and apoptosis of HepG2 cells in a dose-dependent manner. The total apoptosis rate was 0.14% for HepG2 cells not treated with matrine. In contrast, the apoptosis rate was 28.91%, 34.36% and 38.80%, respectively, for HepG2 cells treated with matrine at the concentration of 0.5, 1.0 and 2.0 mg/mL. The remarkable morphological changes were observed under an inverted phase contrast microscope. Abundant cytoplasmic vacuoles with varying sizes were observed in HepG2 cells treated with matrine. Furthermore, vacuolization in cytoplasm progressively became larger and denser when the concentration of matrine was increased. Electron microscopy demonstrated formation of abundant autophagic vacuoles in HepG2 cells after matrine treatment. When the specific autophagic inhibitor, 3-MA, was applied, the number of autophagic vacuoles greatly decreased. MDC staining showed that the fluorescent density was higher and the number of MDC-labeled particles in HepG2 cells was greater in matrine treatment group than in control group. Fewer autophagic vacuoles were observed in the combined 3-MA and matrine treatment group when 3-MA was added before matrine treatment, indicating that both autophagy and apoptosis are activated when matrine-induced death of hepatoma G2 cells occurs. Real-time quantitative RT-PCR revealed that the expression levels of Bax gene, an apoptosis-related molecule, and Beclin 1 gene which plays a key role in autophagy were higher in matrine treatment group than in control group, indicating that Beclin 1 is involved in matrine-induced autophagy and the pro-apoptotic mechanism of matrine may be related to its upregulation of Bax expression.

CONCLUSION: Matrine has potent antitumor activities in HepG2 cells and may be used as a novel effective reagent in treatment of hepatocellular carcinoma.

A single nucleotide polymorphism in the Bax gene promoter affects transcription and influences retinal ganglion cell death

Pro-apoptotic Bax is essential for RGC (retinal ganglion cell) death. Gene dosage experiments in mice, yielding a single wild-type Bax allele, indicated that genetic background was able to influence the cell death phenotype. DBA/2J^Bax+/− mice exhibited complete resistance to nerve damage after 2 weeks (similar to Bax^−/− mice), but 129B6^Bax+/− mice exhibited significant cell loss (similar to wild-type mice). The different cell death phenotype was associated with the level of Bax expression, where 129B6 neurons had twice the level of endogenous Bax mRNA and protein as DBA/2J neurons. Sequence analysis of the Bax promoters between these strains revealed a single nucleotide polymorphism (T^129B6 to C^DBA/2J) at position −515. A 1.5- to 2.5-fold increase in transcriptional activity was observed from the 129B6 promoter in transient transfection assays in a variety of cell types, including RGC5 cells derived from rat RGCs. Since this polymorphism occurred in a p53 half-site, we investigated the requirement of p53 for the differential transcriptional activity. Differential transcriptional activity from either 129B6 or DBA/2J Bax promoters were unaffected in p53^−/− cells, and addition of exogenous p53 had no further effect on this difference, thus a role for p53 was excluded. Competitive electrophoretic mobility-shift assays identified two DNA–protein complexes that interacted with the polymorphic region. Those forming Complex 1 bound with higher affinity to the 129B6 polymorphic site, suggesting that these proteins probably comprised a transcriptional activator complex. These studies implicated quantitative expression of the Bax gene as playing a possible role in neuronal susceptibility to damaging stimuli.