Changes of NF-κB, p53, Bcl-2 and caspase in apoptosis induced by JTE-522 in human gastric adenocarcinoma cell line AGS cells: role of reactive oxygen species

Lycopene Inhibits Activation of Epidermal Growth Factor Receptor and Expression of Cyclooxygenase-2 in Gastric Cancer Cells

Reactive oxygen species (ROS) contribute to the oncogenic phenotype of cancer cells by acting as signaling molecules for inducing proliferation. ROS are known to activate the epidermal growth factor receptor (EGFR), which causes the activation of the Ras/mitogen-activated protein kinases (MAPKs) pathway. The Ras-dependent pathway promotes the activation of nuclear factor-kappa-light-chain-enhancer of activated B cells (NF-κB), a transcriptional modulator of cyclooxygenase-2 (COX-2) that induces cell proliferation. Lycopene is a potent antioxidant carotenoid and is responsible for the red color of fruits and vegetables. This study aims to investigate whether lycopene inhibits proliferation and induces apoptosis in gastric cancer AGS cells by suppressing the EGFR/Ras/MAPK and NF-κB-COX-2 signaling axis. Lycopene decreased cell viability and increased apoptotic indices (DNA fragmentation, apoptosis inducing factor, cleavage of caspase-3 and caspase-9, Bax/Bcl-2 ratio). Lycopene reduced the level of intracellular and mitochondrial ROS and decreased the activation of the ROS-mediated EGFR/Ras/extracellular signal-regulated kinase (ERK) and p38 MAPK pathways, thus leading to attenuation of the DNA-binding activity of NF-κB p50/p50 and the level of COX-2 gene expression. These results show that lycopene-induced apoptosis and inhibition of proliferation occur via inhibition of ROS-activated EGFR/Ras/ERK and p38 MAPK pathways and NF-κB-mediated COX-2 gene expression in AGS cells. In conclusion, consumption of lycopene-enriched foods could decrease the incidence of gastric cancer.

Using Next-Generation Sequencing Transcriptomics To Determine Markers of Post-traumatic Symptoms: Preliminary Findings from a Post-deployment Cohort of Soldiers

Post-traumatic stress disorder is a concerning psychobehavioral disorder thought to emerge from the complex interaction between genetic and environmental factors. For soldiers exposed to combat, the risk of developing this disorder is twofold and diagnosis is often late, when much sequela has set in. To be able to identify and diagnose in advance those at “risk” of developing post-traumatic stress disorder, would greatly taper the gap between late sequelae and treatment. Therefore, this study sought to determine whether the transcriptome can be used to track the development of post-traumatic stress disorder in this unique and susceptible cohort of individuals. Gene expression levels in peripheral blood samples from 85 Canadian infantry soldiers (n = 58 participants negative for symptoms of post-traumatic stress disorder and n = 27 participants with symptoms of post-traumatic stress disorder) following return from deployment to Afghanistan were determined using RNA sequencing technology. Count-based gene expression quantification, normalization and differential analysis (with thorough correction for confounders) revealed genes associated to PTSD; LRP8 and GOLM1. These preliminary results provide a proof-of-principle for the diagnostic utility of blood-based gene expression profiles for tracking symptoms of post-traumatic stress disorder in soldiers returning from tour. It is also the first to report transcriptome-wide expression profiles alongside a post-traumatic symptom checklist.

Effect of Helix aspersa extract on TNFα, NF-κB and some tumor suppressor genes in breast cancer cell line Hs578T

Background:

The garden snail, Helix aspersa, is a big land snail widely found in the Mediterranean countries. It is one of the most consumed species and widely used in zootherapy.

Objective:

The present study was carried out to investigate for the first time the first time the antitumor activity of an aqueous extract from Helix aspersa.

Materials and Methods:

The effect of H. aspersa extract was studied on a triple negative breast cancer cell line Hs578T. Firstly, the morphological changes and the mode of cell death induced by the extract have been evaluated by microscopy and acridine orange/ethidium bromide staining. The effect of the extract at dilution 0.1% and 1% was then tested on some genes, regulators of cell death and proliferation like tumor necrosis factor α (TNFα), NF- κB, and the tumor suppressor genes P53 and PTEN.

Results:

Data demonstrate that the extract induces necrosis in tumor cells. It enhances significantly the expression of TNFα; mRNA levels were 20 and 10 times more important in treated cells compared to nontreated cells. NF-κB and PTEN were inhibited with the dilution 1% after 8 and 24 hours of treatment. P53 expression was further inhibited but only with the highest dose, after 4, 8, and 24 hours.

Conclusion:

Our results show that H. aspersa extract has an antitumor activity against Hs578T cells; it is a potent stimulator for TNFα and a good inhibitor for NF-κB.

Abbreviations used: AO: acridine orange; Bcl-2: B cell lymphoma 2. cDNA: complementary DNA; ELISA: enzyme linked immunosorbent assay; EB: ethidium bromide; IC50: the half maximal inhibitory concentration; mRNA: messenger RNA. MAPK: mitogen-activated protein kinase; NF-κB: nuclearfactorkappa B; PBS: phosphate buffered saline. PI3K: phospho-inositol 3 kinase; PTEN: phosphatase and tensin homolog; ROS: reactive oxygen species. RT-PCR: reverse transcription polymerase chain reaction; TNFα: tumor necrosis factor alpha. TNFR1: TNF receptor-1; TP53: tumor protein 53

Oxidative Stress Triggered by Apigenin Induces Apoptosis in a Comprehensive Panel of Human Cervical Cancer-Derived Cell Lines

Recently, the cytotoxic effects of apigenin (4′,5,7-trihydroxyflavone), particularly its marked inhibition of cancer cell viability both in vitro and in vivo, have attracted the attention of the anticancer drug discovery field. Despite this, there are few studies of apigenin in cervical cancer, and these studies have mostly been conducted using HeLa cells. To evaluate the possibility of apigenin as a new therapeutic candidate for cervical cancer, we evaluated its cytotoxic effects in a comprehensive panel of human cervical cancer-derived cell lines including HeLa (human papillomavirus/HPV 18-positive), SiHa (HPV 16-positive), CaSki (HPV 16 and HPV 18-positive), and C33A (HPV-negative) cells in comparison to a nontumorigenic spontaneously immortalized human epithelial cell line (HaCaT). Our results demonstrated that apigenin had a selective cytotoxic effect and could induce apoptosis in all cervical cancer cell lines which were positively marked with Annexin V, but not in HaCaT (control cells). Additionally, apigenin was able to induce mitochondrial redox impairment, once it increased ROS levels and H₂O₂, decreased the Δψm, and increased LPO. Still, apigenin was able to inhibit migration and invasion of cancer cells. Thus, apigenin appears to be a promising new candidate as an anticancer drug for cervical cancer induced by different HPV genotypes.

Molecular evidence on the protective effect of ellagic acid on phosalone-induced senescence in rat embryonic fibroblast cells

Salient evidence testifies the link between organophosphorus (OPs) exposure and the formation of free radical oxidants; and it is well accepted that free radicals are one of the basic concerns of senescence. To show the oxidative features of phosalone (PLN) as a key member of OPs, to induce senescence in rat embryonic fibroblast (REF) cells and to demonstrate the beneficial effects of the known antioxidant ellagic acid (EA) in diminishing the PLN-induced toxic effects, the levels of cell viability, oxidative stress markers, inflammatory cytokines, telomerase activity, and the expression of the genes related to senescence were investigated. Our results lend support to the hypothesis that PLN enhances the entire premature senescence parameters of REF cells. This accounts for the mechanistic approval of the role of OPs in induction of senescence in rat fibroblasts. Moreover, incorporation of EA diminished PLN toxicity mainly through suppression of p38 and p53 at gene and protein levels, and tempered the inflammation factors (TNF-α, IL-1β, IL-6 and NF-κB), which further affected cell division. Analysis of cell cycle showed that the percentage of G0/G1 arrest, in REF cells treated by EA was elevated as compared to control and PLN treated cells.

Eucommia ulmoides Oliv. (Du-Zhong) Lignans Inhibit Angiotensin II-Stimulated Proliferation by Affecting P21, P27, and Bax Expression in Rat Mesangial Cells

Cortex Eucommiae (Du-zhong) is the dried bark of the Eucommia ulmoides Oliv. The natural products identified from Du-zhong include lignans, iridoids, flavonoids, polysaccharides, terpenes, and proteins, Liu et al. (2012). Lignans, the main bioactive components, were protective against hypertensive renal injury in spontaneous hypertensive rats in our previous study, Li et al. (2012). Moreover, Eucommia lignans also diminished aldose reductase (AR) overexpression in the kidney, Li et al. (2012). However, the pathological mechanism underlying the protective effects of Eucommia lignans remains unknown. Cellular proliferation was reported to contribute to important pathological changes in hypertensive renal injuries, and increased angiotensin II (Ang II) expression was reported to be essential for target-organ damage during hypertension. Ang II is the main effective peptide in the renin-angiotensin system and is considered to be a key mediator in the development of hypertensive nephropathy, Rüster and Wolf (2011). Our preliminary results showed that Eucommia lignans had inhibitory effects on Ang II-induced proliferation of rat mesangial cells. In the present study, we investigated the effects of Eucommia ulmoides on Ang II-induced proliferation and apoptosis of rat mesangial cells. Cell cycle-related genes P21 and P27, and cell apoptosis-related genes Bax and Bcl-2, were determined.

Enhancement of immune activation activities of Spirulina maxima grown in deep-sea water

In this study, the immuno-modulatory and anticancer activities of marine algae, Spirulina maxima grown in deep-sea water (DSW), were investigated. It was found that the extract of S. maxima, cultured in DSW, effectively suppressed the expression of Bcl2 in A549 cells as well as inhibiting various human cancer cells with concentration dependency, which possibly implies that the extracts may play more important roles in controlling cancer cell growth. The secretion of cytokines IL-6 and TNF-α from human B cells was also greatly increased, compared to those of the extract grown in conventional sea-water. The growth of Human Natural Killer (NK) cells in the presence of the extracts from DSW was significantly higher (12.2 × 104 viable cells/mL) when compared to the control (1.1 × 104 viable cells/mL). Based on HPLC analysis, the increase in the biological activities of the extracts from DSW was caused by considerably high amounts of β-carotene and ascorbic acid because the DSW contained high concentrations and good ratios of several key minerals for biosynthesizing β-carotene and ascorbic acid, as well as maintaining high cell growth.

Hepatitis C virus-induced up-regulation of microRNA-155 promotes hepatocarcinogenesis by activating Wnt signaling

Hepatitis C virus (HCV) infection usually induces chronic hepatic inflammation, which favors the initiation and progression of hepatocellular carcinoma (HCC). Moreover, microRNA-155 (miR-155) plays an important role in regulating both inflammation and tumorigenesis. However, little is known about whether and how miR-155 provides the link between inflammation and cancer. In this study we found that miR-155 levels were markedly increased in patients infected with HCV. MiR-155 transcription was regulated by nuclear factor kappa B (NF-κB), and p300 increased NF-κB-dependent miR-155 expression. The overexpression of miR-155 significantly inhibited hepatocyte apoptosis and promoted cell proliferation, whereas miR-155 inhibition induced G(0) /G(1) arrest. Up-regulated miR-155 resulted in nuclear accumulation of β-catenin and a concomitant increase in cyclin D1, c-myc, and survivin. Gain-of-function and loss-of-function studies demonstrated that miR-155 promoted hepatocyte proliferation and tumorigenesis by increasing Wnt signaling in vitro and in vivo, and DKK1 (Wnt pathway inhibitor) overexpression inhibited the biological role of miR-155 in hepatocytes. Finally, adenomatous polyposis coli (APC), which negatively regulates Wnt signaling, was identified as the direct and functional target of miR-155.

CONCLUSION

HCV-induced miR-155 expression promotes hepatocyte proliferation and tumorigenesis by activating Wnt signaling. The present study provides a better understanding of the relationship between inflammation and tumorigenesis, and thus may be helpful in the development of effective diagnosis and treatment strategies against HCV-HCC.

Morphology and infectivity of virus that persistently caused infection in an AGS cell line

A recent report has indicated that proteins and genes of simian virus 5 (SV5) are detected in a human gastric adenocarcinoma (AGS) cell line, which is widely provided for oncology, immunology, and microbiology research. However, the production of infective virions has not been determined in this cell line. In this study, the morphology and infectivity of the virus particles of the AGS cell line were studied by light and electron microscopy and virus transmission assay. The virus particles were approximately 176.0 ± 41.1 nm in diameter. The particles possessed projections 8-12 nm long on the surface and contained a nucleocapsid determined to be 13-18 nm in width and less than 1,000 nm in length. The virus was transmissible to the Vero cell line, induced multinuclear giant cell formation, and reproduced the same shape of antigenic virions. In this study, the persistently infected virus in the AGS cell line was determined to be infective and form reproducible virions, and a new morphological feature of SV5 was determined.

Aging alters tissue resident mesenchymal stem cell properties

Tissue resident mesenchymal stem cells (MSCs) are known to participate in tissue regeneration that follows cell turnover, apoptosis, or necrosis. It has been long known that aging impedes an organism's repair/regeneration capabilities. In order to study the age associated changes, the molecular characteristics of adipose tissue derived MSCs (ASCs) from three age groups of healthy volunteers, i.e., young, middle aged, and aged were investigated. The number and multilineage differentiation potential of ASCs declined with age. Aging reduces the proliferative capacity along with increases in cellular senescence. A significant increase in quiescence of G2 and S phase was observed in ASCs from aged donors. The expression of genes related to senescence such as CHEK1 and cyclin-dependent kinase inhibitor p16(ink4a) was increased with age, however genes of apoptosis were downregulated. Further, an age-dependent abnormality in the expression of DNA break repair genes was observed. Global microRNA analysis revealed an abnormal expression of mir-27b, mir-106a, mir-199a, and let-7. In ubiquitously distributed adipose tissue (and ASCs), aging brings about important alterations, which might be critical for tissue regeneration and homeostasis. Our findings therefore provide a better understanding of the mechanism(s) involved in stem cell aging and regenerative potential, and this in turn may affect tissue repair that declines with aging.

Alleviation of lung injury by glycyrrhizic acid in benzo(a)pyrene exposed rats: Probable role of soluble epoxide hydrolase and thioredoxin reductase

Benzo(a)pyrene [B(a)P] is known to alter lung physiology by interfering in various intracellular pathways including alterations in NF-κB activities, cytokine release and cell survival. NF-κB suppression/activation plays a major role in cell survival status. Present investigation deals with such kind of effects of B(a)P on lungs in relation with soluble epoxide hydrolase (sEH) and thioredoxin reductase (TrxR) activities. Glycyrrhizic acid (GA), an active principle of Glycyrrhiza glabra (Licorice), is known to modulate various molecular processes. In the present study, we investigated the protective effects of GA against B(a)P induced debilities in lungs of Wistar rats. Intratracheal instillation of B(a)P significantly suppressed NF-κB translocation, sEH, TrxR and catalase activities in lung tissue. A marked induction of H(2)O(2) levels along with caspases activation (caspases-2, -3, -6, -8, and -9) in lung tissue after B(a)P exposure was observed. Lung injury was assessed by measuring lactate dehydrogenase (LDH), alkaline phosphatase (ALP), total cell count, total protein, neutrophil elastase activity in bronchoalveolar lavage fluid (BALF). Reduction in phospholipid content further potentiated these parameters. GA oral administration (50 and 100mg/kg b.wt.) significantly showed protection of lung epithelium by suppression of caspases activities in lung tissue and reduction of total protein, total cells, elastase activity, LDH and ALP activities along with fortification of phospholipids in BALF. Histological observations also confirm the findings in above mentioned parameters. Results indicate a strong correlation between amelioration of sEH and TrxR activities, and NF-κB activation. The present investigation gives an insight into probable mechanisms of lung injuries induced by short term exposures of B(a)P and prevention by glycyrrhizic acid.

Genistein Induced Apotosis in Human Gastric Carcinoma Cells

The apoptosis in gastric cancer cells induced by genistein and the relationship between this apoptosis and expression of NF-κB and Caspase-3 were studied. In vitro experiments, MTT assay was used to determine the cell growth inhibitory rate. Transmission fluorescence microscope, transmission electron microscopy, DNA-fragment assay were used to qualitively detect the apoptosis status of gastric cancer line SGC-7901 before and after the genistein treatment. Immunohistochemical staining and Western Blotting were performed to detect the expression of gene NF-κB and Caspase-3. The results showed that genistein inhibited the growth of gastric carcinoma cell line SGC-7901 in a dose-and time-dependent manner. Genistein induced SGC-7901 cells to undergo apoptosis with typically apoptotic characteristics, including morphological changes of chromatin condensation, chromatin crescent formation, nucleus fragmentation and apoptotic body formation. Genistein could reduce the expression of gene NF-κB, and improve the expression of gene Caspase-3.

Inhibiting NF-κB activation by small molecules as a therapeutic strategy

Because nuclear factor-κB (NF-κB) is a ubiquitously expressed proinflammatory transcription factor that regulates the expression of over 500 genes involved in cellular transformation, survival, proliferation, invasion, angiogenesis, metastasis, and inflammation, the NF-κB signaling pathway has become a potential target for pharmacological intervention. A wide variety of agents can activate NF-κB through canonical and noncanonical pathways. Canonical pathway involves various steps including the phosphorylation, ubiquitination, and degradation of the inhibitor of NF-κB (IκBα), which leads to the nuclear translocation of the p50-p65 subunits of NF-κB followed by p65 phosphorylation, acetylation and methylation, DNA binding, and gene transcription. Thus, agents that can inhibit protein kinases, protein phosphatases, proteasomes, ubiquitination, acetylation, methylation, and DNA binding steps have been identified as NF-κB inhibitors. Because of the critical role of NF-κB in cancer and various chronic diseases, numerous inhibitors of NF-κB have been identified. In this review, however, we describe only small molecules that suppress NF-κB activation, and the mechanism by which they block this pathway.

Double-edged swords as cancer therapeutics: simultaneously targeting p53 and NF-kappaB pathways

The p53 and nuclear factor-kappaB (NF-kappaB) pathways play crucial roles in human cancer, in which inactivation of p53 and hyperactivation of NF-kappaB is a common occurrence. Activation of p53 and inhibition of NF-kappaB promotes apoptosis. Although drugs are being designed to selectively activate p53 or inhibit NF-kappaB, there is no concerted effort yet to deliberately make drugs that can simultaneously do both. Recent results suggest that a surprising selection of small molecules have this desirable dual activity. In this Review we describe the principles behind such dual activities, describe the current candidate molecules and suggest mechanisms and approaches to their further development.

Expression of Bag-1 and Bcl-2 and its significance in gastric cancer

AIM: To investigate the expression of Bag-1 and Bcl-2 protein and its clinical significance in gastric cancer (GC).

METHODS: Immunohistochemistry was used to detect the expressison of Bag-1 and Bcl-2 protein in 92 patients with gastric cancer and 40 normal tissues as control.

RESULTS: Compared with normal mucosa, Bag-1 and Bcl-2 were over-expressed in gastric cancerous tissues (60.9% vs 7.5%, 72.8% vs 10%, P<0.01). The expression of Bcl-2 protein was significantly correlated with the differentiation degree (r_s = 0.513, P<0.05) and the expression of Bag-1 was significantly associated with Bcl-2 level in gastric cancer (r_s = 0.522, P<0.01).

CONCLUSION: The over-expression of Bcl-2 leads to uncontrolled growth and unceasingly increases of GC cells by accelerating cell transformation and proliferation. Bag-1 promotes the function of Bcl-2 and co-expression of Bag-1 and Bcl-2 may mean poor prognosis of GC patients.

NF-κB as a molecular target in adjuvant therapy of gastrointestinal carcinomas

AIM

To describe the role of nuclear factor-kappa B (NF-kappaB) in cancer treatment.

METHODS

We searched the Pubmed database (until Oct, 2004) with the keywords of gastrointestinal carcinoma, NF-kappaB, inhibitor, cancer treatment molecular target and chemoresistance. We reviewed the literature in the role of NF-kappaB activation in chemoresistance, tumour growth suppression and enhancement of apoptosis in gastrointestinal carcinomas.

CONCLUSIONS

Several possible strategies for inhibiting NF-kappaB activation are identified. The importance of targeting NF-kappaB as a potential therapeutic approach in clinical medicine was discussed.

Relationship between bcl-2 gene expression and cell proliferation and apoptosis in human gastric carcinomas

AIM: To investigate the relationship between bcl -2 gene expression levels in human gastric carcinoma and the frequency of tumor cell proliferation activity and apoptosis.

METHODS: In situ hybridization and immunohistochemistry methods were used to study the frequencies of expressions of bcl -2 gene and nuclear antigen of proliferating cells (PCNA) in 53 gastric carcinomas. Meanwhile, an in situ apoptotic cell detection (TUNEL method) was adopted to compare the number of apoptotic cells and PCNA with the Bcl -2 protein expression in each case.

RESULTS: Of the 53 gastric carcinomas, 41 and 43 expressed bcl -2 mRNA and Bcl -2 protein, which were count for 77.4% and 81.1% respectively. There was no significant difference between the positive rates obtained by these two methods. The apoptotic index of gastric carcinomas negatively related to PCNA index (r = -0.993, P < 0.01). With the increase of Bcl-2 protein expression , the cell proliferating activity increased but the apoptosis decreased in the tumor cells. Significant difference of cell proliferation and apoptosis existed between +++ group and ++ group of Bcl -2 protein expression (t = 2.552, 2.699, P < 0.05) as well as between the former two groups and the -, + group (t = 4.487, 3.975, 2.807, 3.094, 4.885, 5.816, 3.404, 3.895, P < 0.01) respectively.

CONCLUSION: The overexpression of bcl -2 gene inhibits cell apoptosis and excessive cell proliferation in the development and progress of gastric carcinomas.

On the antioxidant mechanisms of Bcl-2: a retrospective of NF-kappaB signaling and oxidative stress

Antioxidant and prooxidant signaling pathways are emanating as major players in, and regulators of, cell death and apoptosis. Redox conception of the critical role of oxidative stress in determining cell fate is being established-a foundation that craves deeper than the basic understanding of physiochemical interactions to extend beyond that into the realms of deciphering the molecular codes implicated with apoptosis. The proto-oncogene Bcl-2 is no stranger being a major player and decoder in controlling apoptosis, ostensibly via the regulation of redox equilibrium and disequilibrium. One of those potential mechanisms exhibited by Bcl-2 is its ability to counteract the detrimental effects of cell damage caused by free radicals, thereby gaining its well-known property of being an antioxidant. But the question is: what are the molecular mechanisms involved with the antioxidant role of Bcl-2 in the face of cell damage and apoptosis? Currently, a stance is being upheld in that the Bcl-2 antioxidant efficacy should be weighed against its ability to manipulate transcriptional control, through the regulation of specific transcription factors. NF-kappaB is no doubt one of the best candidates when it comes to the arena of oxidative stress, inflammation, and apoptosis. Therein, current themes in the burgeoning antioxidant role of Bcl-2 are exposed within the context of transcriptional control of NF-kappaB, thereby holding potential avenues for alleviating therapeutic approaches in the regulation of apoptosis.

Expression of DNA repair enzyme hMTH1 mRNA and its protein in hepatocellular carcinoma

AIM: To study the expression of DNA repair enzyme hMTH1 mRNA and protein in hepatocellular carcinoma (HCC) tissues, normal liver cell and hepatoma cell lines, and to investigate their function in the progress of HCC.

METHODS: Expression of hMTH1 mRNA in matched HCC tissues(33 cases)/surrounding tissues of HCC (33 cases), normal liver cell L-02 and hepatoma cell lines SMMC7721 HepG2 were detected by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR). hMTH1 protein was detected in corresponding HT tissues (17 cases HT) as well as their surrounding liver tissues (17 cases HST) by immunohistochemistry.

RESULTS: The expression level of hMTH1 mRNA in HT was higher than that in HST (t = 2.424 , P = 0.021<0.05). The expression level of hMTH1 mRNA in two hepatoma cell lines was higher than that in normal liver cell line (F = 6.810, P = 0.009<0.01). The expression of hMTH1 mRNA in SMMC7721 was similar to that in HepG2. hMTH1 protein was 88.2% (15 of 17) positive in HT and 82.4% (14 of 17) in HST and was mainly distributed in hepatocytesi cytoplasm. The protein level of hMTH1 in HCC tissues was correspondingly higher than in their surrounding tissues (t = 2.618, P = 0.019<0.05).

CONCLUSION: Overexpression of hMTH1 mRNA and its protein in the liver tissues of HCC and hepatoma cell lines is found.

Expression of MIB-1 and bcl-2 in hepatocellular carcinoma and paracarcinomatous tissues

AIM: To investigate the effects of MIB-1 and bcl-2 proteins expression in the primary hepatocellular carcinoma(HCC) and their paracarcinomatous tissues.

METHODS: The expression of MIB-1 and bcl-2 proteins was evaluated in paraffin-embedded tissue by immunohistochemical techniques (S-P) in 40 cases of hepatocellular carcinoma.

RESULTS: The positive expression of MIB-1 was located in nucleus. The mean MIB-1 positive rate in HCCs was 27.61±13.26%, while MIB-1 positive cells in paracarcinomatous tissues were 1.24±1.67% (P < 0.001). The expression of MIB-1 in HCCs was related to the cancer grading, the lower the differentiation of HCCs, the higher the MIB-1 proliferation index (P < 0.01). As for the paracarcinomatous tissues the MIB-1 proliferation index of small liver cell dysplasia (LCD) was higher than that of its adjacent liver tissue. However, in larger cell LCD, the MIB-1 index had no significant difference compared with that of its adjacent tissue. The positive rates of bcl-2 in cancer and paracarcinomatous tissues were 17.5% (7/40) and 77.5% (31/40) respectively. The bcl-2 expression was located in cytoplasm and its positive signals were strong and cluster-like in paracarcinomatous tissues, while the number of the bcl-2 positive cell was sporadic and the signals were weak and "piece-meal like" in HCCs.

CONCLUSION: This study shows that the MIB-1 proliferation index reflects the proliferation speed and the degree of anaplasia in HCCs. The higher expression of MIB-1 in small cell LCD suggests that its proliferation is faster than that of large cell LCD and their adjacent liver tissues, so the small cell LCD is more approximate to HCCs. The study also shows that bcl-2 may not directly play a role in liver cell proliferation during the processes of liver cell carcinogenesis, but it may take part in liver cell apoptosis regulated by the reduction of bcl-2 protein level.

Effects of COX-2 inhibitor with cisplatin on proliferation and apoptosis of pancreatic cancer cells

AIM: To investigate the effects of proliferation and apoptosis induced by cyclooxygenase-2 (COX-2) inhibitor celecoxib in combination with cisplatin.

METHODS: The human pancreatic cancer cell line BxPC-3 cells were treated with COX-2 inhibitors celecoxib and cisplatin. The cell relative viability was examined using 3 (4, 5-dimethylethiazoly 1-2-) 2, 5-diphonyl tetrazolium bromide (MTT) assays. the expression of COX-2 mRNA was detected by RT-PCR, flow cytometry and Hoechst-33258 were used to demonstrate apoptotic changes in celecoxib and cisplatin treated cells.

RESULTS: After treatment of BxPC-3 cells with celecoxib, as measured by MTT, cell viability was inhibited in a dose-dependent and time-dependent manner with an IC50 of 100 nM at the time of 24h. The expression of COX-2 mRNA could be significantly decreased by celecoxib. Furthermore, we demonstrated that the combination of celecoxib with cisplatin inhibited cell growth and induced cell apoptosis to a greater degree than either compound alone. The apoptotic morphologies were demonstrated by Hoechst-33 258.

CONCLUSION: Combination of celecoxib with cisplatin inhibits cell proliferation and induces cell apoptosis, and the potent effectiveness of celecoxib in combination with gemcitabine may hold a promise in the clinical treatment of pancreatic cancer.

Effects of BAK gene over-expression on apoptosis in gastric cancer cells and its molecular mechanisms

AIM: To explore the apoptosis-inducing effects of extrinsic BAK gene transfer and its over-expression on gastric cancer cells and its molecular mechanisms.

METHODS: The eukaryotic expression for BAK gene was constructed and transferred into gastric cancer MKN-45 cell line. After being transferred for 1 to 5 d, cellular BAK gene expression was detected by RT-PCR and Western blotting methods. The growth activities of cancer cells were detected by cell count and MTT colorimetry. Cell cycle changes were assayed by flow cytometry. Cellular apoptosis was assayed by electronic microscopy and in situ terminally labeled transferase technique (TUNEL). Cellular caspase-3 activities were observed by colorimetric method.

RESULTS: After being transferred for 1 to 5 d, cellular BAK mRNA and protein expression levels were significantly increased (P < 0.01). In vitro growth of gastric cancer cells was inhibited by 11.6-35.3% (P < 0.01). The cellular proliferation activities were decreased by 10.2-32.4% (P < 0.01), with cell cycle being blocked at G0/G1 phase. Partial cancer cells presented the characteristic morphological changes of apoptosis, with the apoptotic rates being 21.4% (P < 0.01). The cellular caspase-3 activities were enhanced by 4.45 times (P < 0.01).

CONCLUSION: Transfection of extrinsic BAK gene, resulting in its over-expression, can significantly induce apoptosis of gastric cancer MKN-45 cells through activating caspase-3, which is a potential strategy for gene therapy of gastric cancer.

Expression of HSP 70 and caspase 3 and their significance in hepatocellular carcinoma tissues

AIM: To investigate the expression of heat shock protein 70 (HSP70) and caspase 3 protein and their clinical significance in hepatocellular carcinomas and surrounding liver tissues.

METHODS: The expression of HSP70 and caspase 3 protein were detected by immunohistochemistry in hepatocellular carcinomas (HCC) and their surrounding liver tissues.

RESULTS: The positive rate and intensity of HSP70 in HCCs were significantly higher than those in pericarcinomatous liver tissues (68.6% vs 31.4%, P < 0.01), and these of caspase protein were significantly lower (17.1% vs 35.7%, P < 0.01). The expression level of HSP70 and caspase protein in HCCs was remarkably related to differentiation degree and tumor size of HCCs, and the poorer differentiation, the stronger the expression of HSP70 (F = 5.219 and 5.421 respectively, P < 0.01), the weaker the expression of caspase 3 protein (F = 5.944 and 4.571 respectively, P < 0.01). The correlation analysis indicated that there was a negative relationship between expression of HSP70 and caspase protein in HCC and their surrounding liver tissues (r = 0.4 126 and 0.5 237 respectively, P < 0.01).

CONCLUSION: The expression of HSP70 may make uncontrolled growth and unceasingly increased malignant degree of HCC by accelerating cell transformation and proliferation and inhibiting apoptosis. HSP70 may be an important marker for evaluation of prognosis in patients with HCC.

Expression of apoptosis-related proteins and proliferating cell nuclear antigen during stomach canceration

AIM: To study the role of apoptosis-related gene p53, Bcl-2, and proliferating cell nuclear antigen (PCNA) in gastric cancinogenesis.

METHODS: Immunohistochemical method (LSAB) was used to assess p53, Bcl-2, PCNA expression in specimens of 52 patients with gastric cancer and precancerous lesions.

RESULTS: In the patients with intestinal metaplasia, dysplasia and gastric cancer, the expression rates of p53 were 27.8%, 38.2% and 57.7% respectively. The expression rates of Bcl-2 were 33.3%, 50.0% and 65.4%, and PCNA indexes were 41.4±13.0, 47.9±8.9 and 53.0±11.9 respectively. In patients with intestinal-type carcinoma, p53 and Bcl-2 remained expressed in all precancerous tissues after development into cancer. In diffuse-type carcinoma, the positive Bcl-2 expression became negative in one patient. PCNA LI markedly increased from precancerous lesions to cancer, and a significant difference was observed in intestinal-type carcinoma (P < 0.001).

CONCLUSION: The expression of p53 and Bcl-2 significantly influences the development of intestinal-type gastric carcinoma, and the proliferating activity of the cancer cells gradually increase.

Involvement of NF-kappa B activation in P-glycoprotein expression in vincristine-resistant human gastric cancer cells

AIM: To investigate the effect of vincristine on activation of nuclear factor-kappa B (NF-κB) and expression of p-glycoprotein (P-gp) in vincristine-resistant human gastric cancer SGC7901 cells (SGC7901/VCR) and the parent sensitive clone (SGC7901).

METHODS: NF-κB-DNA binding activity was determined by electrophoretic mobility shift assay (EMSA). Levels of inhibitory B (IB-) and P-gp were measured by cellular-ELISA. And immunocytochemistry was used to detect the translocation of P65.

RESULTS: IN comparison with the parent SGC7901 cells, the basal and vincristine-induced NF-κB-DNA binding activity at various concentrations were all higher in the SGC7901/VCR cells. Concurrent with the NF-κB activation, vincristine-induced IB- degradation and P-gp upregulation were also found to be highly enhanced in the SGC7901/VCR cells than that in the sensitive SGC7901 cells. In the SGC7901/VCR cells, the activation of NF-κB induced by vincristine showed a positive relation with the level of P-gp expression (r = 0.977, P < 0.01). And nuclear translocation of P65 occurred concomitantly with NF-κB activation. Furthermore, the inhibition of NF-κB by MG-132, a proteasome inhibitor, could reduce NF-κB activation, IB- degradation and P-gp upregulation.

CONCLUSION: The enhancement of NF-κB activation correlates with vincristine resistance and NF-κB may play an important role in the regulation of the P-gp expression.

Survivin, versatile modulation of cell division and apoptosis in cancer

Survivin is a member of the inhibitor of apoptosis (IAP) gene family that has attracted attention from several viewpoints of basic and translational research. Its cell cycle-regulated expression at mitosis and association with the mitotic apparatus have been of interest to cell biologists studying faithful segregation of sister chromatids and timely separation of daughter cells. Investigators interested in mechanisms of apoptosis have found survivin an evolving challenge: while survivin inhibits apoptosis in vitro and in vivo, this pathway may be more selective as compared to cytoprotection mediated by other IAPs. Finally, basic and translational researchers in cancer biology have converged on survivin as a pivotal cancer gene, not simply for its sharp expression in tumors and not in normal tissues, but also for the potential exploitation of this pathway in cancer diagnosis and therapy. The objective of the present contribution is to line up current evidence and emerging concepts on the multifaceted functions of survivin in cell death and cell division, and how this pathway is being pursued for novel cancer therapeutic strategies.

Molecule action mechanisms of NM-3 on human gastric cancer SGC-7901 cells in vivo or in vitro

AIM: To study the molecule action mechanisms of NM-3 on the growth of human gastric cancer SGC-7901 cells in vivo or in vitro.

METHODS: SGC-7901 from human non-differentiated gastric cancer cell line was cultured with NM-3 at 100 mg/mL for 24 h. We observed its inhibitory rate and the density of micro-vascular growth in grafted mice with human gastric cancer SGC-7901. The apoptosis of human gastric cancer SGC-7901 was revealed in NM-3 treatment group by using terminal deoxynucleotidyl transferase-mediated deoxy-uridine triphosphate-fluorescene nick end labeling (TUNEL) method and flow cytometry analysis.

RESULTS: The growth of SGC-7901 cells was markedly inhibited compared with control growp, which was smaller than that in normal saline control group (4.17 g ± 0.22 g vs 9.45 g ± 1.38 g, P < 0.01). The level of apoptosis of human gastric cell line SGC-7901 was obviously increased in NM-3 treatment group at 1 mg.L^-1 for 24 h. NM-3 inducing apoptotic index in NM-3 plus carboplatin group was 3.5 times that of carboplatin control group (TUNEL: 27.98% ± 6.12% vs 12.94% ± 2.12%, FACScan: 26.86% ± 5.69% vs 11.86% ± 1.09%, P < 0.01). Western blot analysis showed that the apoptotic index of human gastric cancer was elevated for 12, 24 and 36 h with an evident time-effect relationship in groups at 100 mg.L^-1. NM-3 enhanced the inhibitive effects and sensitivity of chemotherapy for human gastric cancer in nude mice. These results suggested that NM-3 played a key inhibitive role in the growth of grafted human gastric cancer in nude mice.

CONCLUSION: NM-3 can inhibit the growth of human gastric cancer cell line SGC-7901, and enhance the sensitivity of carboplatin on SGC-7901 and induced its apoptosis.

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Apoptosis-inducing effect of recombinant Caspase-3 expressed by constructed eukaryotic vector on gastric cancer cell line SGC7901

AIM: To investigate the apoptosis-inducing effect of Caspases-3 expressed by constructed eukaryotic vector on gastric cancer cell line SGC7901.

METHODS: PCR was employed to amplify the sequences of both small and large subunits of Caspases-3. Its products were separately cloned into the Sma I site of pBluescript KS⁺ to generate both plasmids pBS/SS and pBS/LS. The small subunit fragment was excised from plasmid pBS/SS with BamH I and then inserted into the BamH I site of plasmid pBS/LS preceding that of the large subunit to yield plasmid pBS/Rev-Caspase-3. Rev-Caspase-3 cDNA was excised with Kpn I + Xba I and then subcloned into plasmid pcDNA3.1 (+) to construct Rev-Caspase-3 eukaryotic expression vector pcDNA/Rev-Caspase-3, which was used to transiently transfect SGC7901 cell line. Cell count, MTT assay and electron microscopy were used to confirm the antiproliferation and apoptosis-inducing effect of Rev-Caspase-3 expression on gastric cancer cells.

RESULTS: Plasmid pBS/Rev-Caspase-3 and eukaryotic expression vector pcDNA/Rev-Caspase-3 were successfully constructed. SGC7901 cells were transiently transfected by either pcDNA/Rev-Caspase-3 or pcDNA3.1 (+) for 24, 48, 72, and 96 h respectively. Cell growth was measured by cell count and MTT assay. In cell count assay, the cell numbers were 1.8 × 10⁶, 1.55 × 10⁶, 2.0 × 10⁶, and 3.1 × 10⁶ in the experimental group and 2.5 × 10⁶, 3.1 × 10⁶, 4.0 × 10⁶, and 5.7 × 10⁶ in the control group at 24, 48, 72 and 96 h respectively. The growth of SGC7901 cells was suppressed by Rev-Caspase-3 in a time-dependent manner (P < 0.05). The results of MTT assay were similar to that of cell count (P < 0.05). The characteristics of apoptosis such as chromatin condensation, crescent formation and margination were seen and more obvious with time in the given-experimental period in the experimental group, but not easily observed in the control group.

CONCLUSION: The expression of Rev-Caspase-3 by the constructed eukaryotic vector can significantly induce apoptosis of gastric cancer cell line SGC7901, which may exhibit a potential way in gastric cancer gene therapy.

Isolation of a novel member of small G protein superfamily and its expression in colon cancer

AIM: APMCF1 is a novel human gene whose transcripts are up-regulated in apoptotic MCF-7 cells. In order to learn more about this gene’s function in other tumors, we cloned its full length cDNA and prepared its polyclonal antibody to investigate its expression in colon cancers with immunohistochemistry.

METHODS: With the method of 5’ rapid amplification of cDNA end (RACE) and EST assembled in GenBank, we extended the length of APMCF1 at 5’ end. Then the sequence encoding the APMCF1 protein was amplified by RT-PCR from the total RNA of apoptotic MCF-7 cells and cloned into the prokaryotic expression vector pGEX-KG to construct recombinant expression vector pGEX-APMCF1. The GST-APMCF1 fusion protein was expressed in E. coli and used to immunize rabbits to get the rabbit anti-APMCF1 serum. The specificity of polyclonal anti-APMCF1 antibody was determined by Western blot. Then we investigated the expression of Apmcf1 in colon cancers and normal colonic mucosa with immunohistochemistry.

RESULTS: A cDNA fragment with a length of 1745 bp was obtained. APMCF1 was mapped to chromosome 3q22.2 and spanned at least 14.8 kb of genomic DNA with seven exons and six introns contained. Bioinformatic analysis showed the protein encoded by APMCF1 contained a small GTP-binding protein (G proteins) domain and was homologous to mouse signal recognition particle receptor β(SRβ). A coding region covering 816 bp was cloned and polyclonal anti-APMCF1 antibody was prepared successfully. The immunohistochemistry study showed that APMCF1 had a strong expression in colon cancer.

CONCLUSION: APMCF1 may be the gene coding human signal recognition particle receptor β and belongs to the small-G protein superfamily. Its strong expression pattern in colon cancer suggests it may play a role in colon cancer development.

In situ quantitative study of BAG-1 and BAD in extrahepatic cholangiocarcinoma

AIM

To detect the expression of apoptosis related proteins BAG-1 and BAD and to investigate their functions of apoptosis modulation and relations to tumor differentiation in extrahepatic cholangiocarcinoma.

METHODS

Quantitative in situ methods of DAKO EnvisionTM Systems immunohistochemistry in combination with computer-assisted image analysis and apoptotic cells counting were used to observe the expression levels of BAG-1 and BAD and the apoptosis indexes in 42 cases of extrahepatic cholangiocarcinoma.

RESULTS

The expression levels of BAG-1 and BAD were measured with average absorbance (A) derived from the quantitative image analysis. Among 24, 13 and 5 cases of well, moderately and poorly differentiated extrahepatic cholangiocarcinomas, the average A of BAG-1 was respectively 0.068±0.037, 0.112±0.057 and 0.152±0.062, of BAD was respectively 0.079±0.053, 0.138±0.058 and 0.165±0.061, and the apoptotic indexes examined in the hematoxylin-and-eosin-stained specimens were respectively 1.1±0.5, 1.7±0.3 and 3.5±1.3. The expression levels of BAG-1 and BAD and the apoptotic indexes were increased obviously from well, moderately to poorly differentiated extrahepatic cholangiocarcinoma (P<0.05). The expression level of BAD was correlated to the apoptotic indexes (P<0.01).

CONCLUSION

Expressions of BAG-1 and BAD and apoptosis indexes were all associated with differentiation of extrahepatic cholangiocarcinoma. BAG-1 and BAD may take part in the apoptosis modulation of the tumor.

X-ray induced L02 cells damage rescued by new anti-oxidant NADH

AIM: To explore molecular mechanism of nicotinamide adenine dinucleotide (NADH) antagonization against X-ray induced L02 cells damage.

METHODS: L02 liver cells were cultured in RPMI 1640, exposed to X-ray irradiation and continued to culture in the presence or absence of NADH. Cellular viability was analyzed by routine MTT methods. The percent age of apoptotic cells and positive expressions of p53, bax and bcl-2, fas, fasL proteins were determined by FCM. Level of intracellular ROS was determined by confocal microscope scanning. Morphological change was detected by scanning electron micrograph.

RESULTS: The viability of L02 cells was decreased with increasing dose of X-ray irradiation. NADH could not only eliminate the apoptosis induced by X-ray irradiation, but also up-regulate expression of bcl-2 protein and down-regulate expression of p53, bax, fas and fasL proteins (P < 0.05). At the same time, NADH could reduce level of intracellular ROS in radiated L02 cells.

CONCLUSION: NADH has marked anti-radiation effect, its mechanism may be associated with up-regulation of bcl-2 expression and down-regulation of p53, bax fas and fasL expression, as well as decline of intracellular ROS. However, further investigation of its mechanism is worthwhile.

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

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

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

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

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

Expression of apoptosis-associated proteins and proliferating cell nuclear antigen (PCNA) in precancerous lesions of stomach

AIM

To investigate the role of apoptosis-associated protein P53, Bcl-2, and proliferating cell nuclear antigen (PCNA) in different transformation in precancerous lesions of the stomach.

METHODS

Immunohistochemical method (LSAB) was used to assess P53, Bcl-2, and PCNA expressions in specimens from patients with (cancerous group, n = 52) and without (non-cancerous group, n = 56) gastric cancer.

RESULTS

The occurrence of gastric carcinoma had close correlation with the expression intensity of P53, Bcl-2 and PCNA. PCNA LI in cancerous group was significantly higher than that in non-cancerous group (P<0.01). In cancerous group, the majority (88.5%) had altered expression in one or more genes; multiple altered expression was found in 51.9%. The difference of multiple altered expression between cancerous group and non-cancerous group was statistically significant (P<0.05).

CONCLUSION

Multiple altered expression of P53, Bcl-2 and PCNA and their synergistic action might play a promotional role in the pathogenesis of gastric carcinoma, and the cell proliferative activity was significantly increased in gastric cancer.

Expression of NGF family and their receptors in gastric carcinoma: A cDNA microarray study

AIM: To investigate the expression of NGF family and their receptors in gastric carcinoma and normal gastric mucosa, and to elucidate their effects on gastric carcinoma.

METHODS: RNA of gastric cancer tissues and normal gastric tissues was respectively isolated and mRNA was purified. Probes of both mRNA reverse transcription product cDNAs labled with α-³³P dATP were respectively hybridized with Atlas Array membrane where NGF and their family genes were spotted on. Hybridized signal images were scanned on phosphor screen with ImageQuant 5.1 software after hybridization. Normalized values on spots were analyzed with ArrayVersion 5.0 software. Differential expression of NGF family and their receptors mRNA was confirmed between hybridized Atlas Array membranes of gastric cancer tissues and normal gastric mucosa, then their effects on gastric carcinoma were investigated.

RESULTS: Hybridization signal images on Atlas Array membrane appeared in a lower level of nonspecific hybridization. Both of NGF family and their receptors Trk family mRNA were expressed in gastric cancer and normal gastric mucosa. But adversely up-regulated expression in other tissues and organs. NGF, BDGF, NT-3, NT-4/5, NT-6 and TrkA, B and C were down-regulated simultaneously in gastric carcinoma in comparison with normal gastric mucosa. Degrees of down-regulation in NGF family were greater than those in their receptors Trk family. Down-regulation of NT-3 and BDGF was the most significant, and TrkC down-regulation level was the lowest in receptors Trk family.

CONCLUSION: Down-regulated expression of NGF family and their receptors Trk family mRNA in gastric cancer is confirmed. NGF family and their receptors Trk family probably play a unique role in gastric cancer cell apoptosis by a novel Ras or Raf signal transduction pathway. Their synchronous effects are closely associated with occurrence and development of gastric carcinoma induced by reduction of signal transduction of programmed cell death.

Primary adenocarcinomas of lower esophagus, esophagogastric junction and gastric cardia: in special reference to China

Gastric cardia adenocarcinoma (GCA) is an under-studied subject. The pathogenesis, molecular changes in the early stage of carcinogenesis and related risk factors have not been well characterized. There is evidence, however, that GCA differs from cancer of the rest of the stomach in terms of natural history and histopathogenesis. Adenocarcinomas of the lower esophagus, esophagogastric junction (EGJ) and gastric cardia have been given much attention because of their increasing incidences in the past decades, which is in striking contrast with the steady decrease in distal stomach adenocarcinoma. In China, epidemiologically, GCA shares very similar geographic distribution with esophageal squamous cell carcinoma (SCC), especially in Linzhou (formerly Linxian County), Henan Province, North China, the highest incidence area of esophageal SCC in the world. Historically, both GCA and SCC in these areas were referred to as esophageal cancer (EC) by the public because of the common syndrome of dysphagia. In Western countries, Barrett's esophagus is very common and has been considered as an important precancerous lesion of adenocarcinoma at EGJ. Because of the low incidence of Barrett's esophagus in China, it is unlikely to be an important factor in early stage of EGJ adenocarcinoma development. However, Z line up-growth into lower esophagus may be one of the characteristic changes in these areas in early stage of GCA development. Whether intestinal metaplasia (IM) is a premalignant lesion for GCA is still not clear. Higher frequency of IM observed at adjacent GCA tissues in Henan suggests the possibility of IM as a precancerous lesion for GCA in these areas. Molecular information on GCA, especially in early stage, is very limited. The accumulated data about the changes of tumor suppressor gene, such as p53 mutation, and ontogeny, such as C-erbB2, especially the similar alterations in GCA and SCC in the same patient, indicated that there might be some similar risk factors, such as nitrosamine, involved in both GCA and SCC in Henan population. The present observations also suggest that GCA should be considered as a distinct entity.

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

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

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

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

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

Expression of survivin protein in human colorectal carcinogenesis

AIM: To identify the role of survivin in colorectal carcinogenesis and the relationship between Survivin and histological differentiation grade of colorectal carcinoma.

METHODS: Immunohistochemical staining of survivin by using the monoclonal antibody was performed by the standard streptavidin-peroxidase (SP) technique for the 188 paraffin sections which included 30 normal colorectal mucosas, 41 adenomas with low grade dysplasia, 30 adenomas with high grade dysplasia, and 87 colorectal carcinomas which were classified as high, middle and low differentiated subgroups which included 33, 28, 26 cases respectively.

RESULTS: Expression of survivin was observed in the cytoplasm of adenoma with dysplasia and colorectal carcinoma cells. No immunoreactivity of survivin was seen in normal mucosas. The positive rate of survivin increased in the transition from normal mucosas to adenomas with low grade dysplasia to high grade dysplasia/carcinomas (0.0%, 31.7%, 56.7% and 63.2% respectively). But the difference between high grade dysplasia and carcinomas had no statistical significance. Positive rate was not related to histological differentiation grade of colorectal carcinoma. Moreover, there was no correlation between histological differentiation grade of colorectal carcinoma and immunoreactive intensity of survivin.

CONCLUSION: The expression of survivin is the essential event in the early stage of colorectal carcinogenesis and plays an important role in the transition sequence and it is not related to histological differentiation grade of colorectal carcinoma. It thus may provide a new diagnostic and therapeutic target in colorectal cancer.

Docetaxel inhibits SMMC-7721 human hepatocellular carcinoma cells growth and induces apoptosis

AIM: To investigate the in vitro anti-hepatocellular carcinoma (HCC) activity of docetaxel against SMMC-7721 HCC cells and its possible mechanism.

METHODS: The HCC cells were given different concentrations of docetaxel and their growth was measured by colony forming assay. Cell cycle and apoptosis were analyzed by flow cytometry and fluorescence microscopy (acridine orange/ethidium bromide double staining, AO/EB), as well as electronic microscopy. The SMMC-7721 HCC cell reactive oxygen species (ROS) and glutathione (GSH) were measured after given docetaxel.

RESULTS: Docetaxel inhibited the hepatocellular carcinoma cells growth in a concentration dependent manner with IC₅₀ 5 × 10^-10 M. Marked cell apoptosis and G2/M phase arrest were observed after treatment with docetaxel ≥ 10^-8 M. Docetaxel promoted SMMC-7721 HCC cells ROS generation and GSH deletion.

CONCLUSION: Docetaxel suppressed the growth of SMMC-7721 HCC cells in vitro by causing apoptosis and G2/M phase arrest of the human hepatoma cells, and ROS and GSH may play a key role in the inhibition of growth and induction of apoptosis.

The study of chemiluminescence in gastric and colonic carcinoma cell lines treated by anti-tumor drugs

AIM: To study the influence of chemotherapy on proliferation activation of tumor cell by observing the change of chemiluminescence (CL) and cell cycle in various tumor cell lines after mitomycin C treated.

METHODS: BGC823 and LoVo cell lines were all cultured in RPMI-1640, and then were adjusted to a concentration of 1 × 10⁵ cells/mL in fresh media and incubated for 24 h. Mitomycin C (100 ng·L^-1) was added to each bottle. All indeses were examined after 24 h. No Mitomycin C was added in control group. Each group contained 8 samples. Flow cytometric analysis and luminol-dependent CL were used to investigate the effect of mitomycin C on two gastrointestinal carcinoma cell lines.

RESULTS: BGC823 and LoVo cell lines incubated with MMC for 24 h. We discovered that the emergence of peak of CL stimulated by PHA was postponed significantly (BGC823: 12.63 ± 3.21 vs 4.50 ± 1.04, LoVo: 13.25 ± 2.96 vs 5.12 ± 1.36, P < 0.01) and the peak intension of CL was reduced significantly (BGC823: 120.25 ± 16.61 vs 248.38 ± 29.17, LoVo: 98.13 ± 10.49 vs 267.50 ± 18.56, P < 0.01). The PI of cell lines was decreased significantly (BGC823: 51.87 ± 4.82 vs 25.44 ± 2.26, LoVo: 47.11 ± 1.04 vs 24.23 ± 0.37, P < 0.01) and the apoptotic fractions changed by contraries (BGC823: 26.25 ± 5.29 vs 9.83 ± 2.51, LoVo: 33.50 ± 3.68 vs 9.63 ± 1.44, P < 0.01).

CONCLUSION: CL can be used to measure activation of tumor cells. We discovered that the ground CL intensions of two cell lines were not high but increased rapidly after stimulation of PHA. The CL peak ranged from 4-5 min, and then decreased gradually. The results were not reported before. CL of tumor cell has close correlativity with the dynamics of cell cycle and can reflect the feature of oxidation metabolism and proliferation activation of tumor cell. So it can be used to observe the influence of chemotherapy drug on metabolism and proliferation activation of tumor cell and screen out chemotherapy drugs to which tumor cells are sensitive.

Expression of cyclooxygenase-2 in pancreatic cancer and its correlation with p53

AIM: To investigate the expressions of COX-2 and p53 in human pancreatic cancer and their correlation with biological behaviors of pancreatic cancer.

METHODS: The expressions of COX-2 and p53 in 51 specimens of human pancreatic ductal adenocarcinoma and 11 specimens of normal tissues adjacent human pancreatic ductal adenocarcinoma were detected with immunohistochemistry by Envision.

RESULTS: The detectable rate of COX-2 and p53 in pancreatic ductal adenocarcinoma were 74.5% and 60.8%, respectively; but none in adjacent normal tissues. The expression of COX-2 was significantly associated with the clinical stages and metastasis status of lymph nodes (P = 0.022, 0.036), but not with histological grade (P = 0.152). The expression of p53 was significantly correlated with the lymph node metastasis status (P = 0.035), but not with their histological grades and clinical stages (P = 0.131, 0.078). There was a significant correlation between the expression of COX-2 and p53 (r = 0.452, P = 0.001). Conditions such as age, sex, tumor size and location had no relation with expression of COX-2 or p53.

CONCLUSION: The cooperation of COX-2 and p53 may play a pivotal role in the carcinogenesis and the progression in pancreatic cancer. They may provide new targets for the therapy of pancreatic cancer.

EDTA-induced activation of Ca-regulated proteins in the vaginal mucosa

The effects of EDTA on the expression and topologic localization of mitogen-activated protein (MAP) kinases (ERK, JNK, and p38), along with nitric oxide synthase (NOS), I-KappaB, and p53 were examined to elucidate the host response provoked by the intravaginal application of a female controlled drug delivery system (FcDDS) containing a spermicidal/microbicidal agent and EDTA. Immunohistochemical and immunoblotting studies were conducted to identify and quantitate the EDTA-inducible proteins in vaginal mucosa. The content of nitrite, which is one of the primary stable breakdown products of nitric oxide (NO), was determined to correlate the expression of NOS with NO formation in HeLa cervical carcinoma cell line. The immunohistochemical study demonstrated that the modulation of the calcium gradient by EDTA activated MAP kinases (ERK and JNK) in the rabbit vaginal mucosa. The results of Western immunoblot study demonstrated differential expression of MAP kinases (ERK and JNK) with EDTA treatment, whereas the expression of NOS and NF-KappaB was not affected by EDTA. There was no significant difference in nitrite production in the HeLa cell line upon exposure to EDTA compared with the control, which was consistent with the results of the Western blot study. The results of this work support that the regulation of MAP kinase was affected by calcium, which is controlled by chelation activity of EDTA. The specific tissue responses exerted by the loading components of a biomaterial-based system should be fully taken into consideration for its intravaginal application.

Relationship between Egr-1 gene expression and apoptosis in esophageal carcinoma and precancerous lesions

AIM: To study the expression of early growth response gene-1 (Egr-1 gene) and Bcl-X/_L protein and its relationship with the cell apoptosis in human esophageal carcinoma(EC) and precancerous lesions.

METHODS: In situ hybridization(ISH), immunohistochemistry (IHC) and TUNEL method were used respectively to detect Egr-1mRNA,Egr-1 protein, apoptosis related-protein Bcl-X/_L and cell apoptosis in situ from 66 cases of esophageal squamous cell carcinoma and their upper cut edge and paracancerous mucosa.

RESULTS: Egr-1 gene in situ hybridization, Bcl-X/_L immunohistochemistry positive products were located in the cytoplasm, while Egr-1 immunohistochemistry and TUNEL positive signal were located in the nuclei. The apoptosis index(AI) and the frequency of apoptosis occurrence were increased gradually from precancerous lesion to cancer (P < 0.01) and the expression of Egr-1mRNA and Egr-1 protein in dysplasia was the highest among all specimens (P < 0.01). The AI of Egr-1 positive cancer tissues was much higher than that of Egr-1 negative cancer tissues (P < 0.01), while the AI of Bcl-X/_L positive cancer tissues was much lower than that of Bcl-X/_L negative cancer tissues (P < 0.01). The AI and Egr-1 expression were not correlated with invasiveness and lymphatic metastasis in EC.

CONCLUSION: Cell apoptosis was present through esophageal carcinogenesis. The expression of Egr-1 mRNA and Egr-1 protein were high in precancerous lesion of esophagus. The AI was increased significantly in Egr-1 positive squamous cell carcinoma. Egr-1 might promote apoptotic effect. Egr-1 expression and cell apoptosis may have an important biological significance in esophageal carcinogenesis.

Intravenous chemotherapy for resected gastric cancer: meta-analysis of randomized controlled trials

AIM: To assess the safety and efficacy of different intravenous chemotherapeutic regimens in patients with gastric carcinomas who had undergone gastrectomy.

METHODS: A meta-analysis of all the relevant randomized controlled trials (RCTs) was performed. Language was restricted to Chinese and English. RCTs were identified from Medline and Embase (1980-2001/4), and Chinese Bio-medicine Database (1990-2001/1). Literature references were checked at the same time. We included randomized and quasi-randomized trials comparing the efficacy of intravenous chemotherapy after gastrectomy with that of surgery alone in patients with confirmed gastric carcinomas who had undergone gastrectomy. Selection criteria were: randomized or quasi-randomized trials with following-up results; Trials could be double-blind, single-blind or not blind; Chemotherapy groups were given intravenous chemotherapy after gastrectomy without neo-adjuvant chemotherapy, intraperitoneal hyperthermic perfusion, radiotherapy or chemoimmunotherapy; Controlled group included those receiving gastrectomy alone. The following data were extracted: the number of survival and death by the end of the follow-up; the different agents and doses of the intravenous chemotherapy; the baseline of the chemotherapy group and the controlled arm; the serious adverse events; the statistical consideration; cost-effectiveness analysis. The statistical analysis was performed by RevMan4.1 software which was provided by the Cochrane Collaboration. A P value of < 0.05 was considered statistically significant. Meta-analysis was done with random effects model. Heterogeneity was checked by chi-square test. Sensitivity analysis was performed by excluding the trials in which Jadad-scale was only 1 score. The result was expressed with odds ratio (OR) for the categorical variable.

RESULTS: Fourteen trials involving 4543 patients were included. Meta-analysis was done with random effects model Heterogeneity and sensitivity analysis were performed also. The effect of intravenous chemotherapy after gastrectomy was better than surgery alone (odds ratio 0.56, 95%CI 0.40-0.79). There was a significant difference between the two groups by u-test (P = 0.0008). Sensitivity analysis revealed the same difference (odds ratio 0.81, 95%CI 0.70-0.94). Of fourteen trials, only three studies were of high quality according to the Jadad-scale (with three score). There was one meta-analysis trial and the others, about ten trials, were of low quality. There was no trial which mentioned sample-size calculation, allocation concealment, intention-to-treat analysis. Most of the trials didn’t describe the blind-procedure. There were five trials which detailed the side-effects according to the toxicity grade by WHO standard. The side-effects halting treatment were haematologic and biochemical toxicity, debilitating nausea and vomiting. There were two patients died of chemotherapy toxicity.

CONCLUSION: Based on the review, intravenous chemotherapy after gastrectomy may have positive treatment effect on gastric cancer. However, the evidence is not strong because of the general low methodologic quality of the RCTs. Therefore, we can’t make the conclusion that intravenous chemotherapy after gastrectomy may have better treatment effect on gastric cancer than that of surgery alone. Rigorously designed, randomised, double-blind, placebo-controlled trials are required.

Apoptosis of hepatoma cells SMMC-7721 induced by Ginkgo biloba seed polysaccharide

AIM: To study the apoptosis of hepatoma cells SMMC-7721 induced by polysaccharide isolated from Ginkgo biloba seed.

METHODS: Ginkgo biloba seed polysaccharide (GBSP) was isolated by ethanol fractionation of Ginkgo biloba seed and purified by Sephadex G-200 chromatography. The purity of GBSP was verified by reaction with iodine-potassium iodide and ninhydrin and confirmed by UV spectrophotometer, cellulose acetate membrane electrophoresis and Sepharose 4B gel filtration chromatography. The Scanning Electron Microscope (SEM) and Flow Cytometry (FCM) were used to examine the SMMC-7721 cells with and without GBSP treatment at 500 mg/mL for 36 h.

RESULTS: GBSP product obtained was of high purity with the average molecular weight of 1.86 × 10⁵. Quantitative analysis of SMMC-7721 cells in vitro with FCM showed that the percentages of G2-M cells without and with GBSP treatment were 17.01% ± 1.28% and 11.77% ± 1.50% (P < 0.05), the debris ratio of the cells were 0.46% ± 0.12% and 0.06% ± 0.06% (P < 0.01), and the apoptosis ratio of cells was 3.84% ± 0.55% and 9.13% ± 1.48% (P < 0.01) respectively. Following GBSP treatment, microvilli of SMMC-7721 cells appeared thinner and the number of spherical cells increased markedly. Most significantly, the apoptosis bodies were formed on and around the spherical cells treated with GBSP.

CONCLUSION: GBSP could potentially induce the apoptosis of SMMC-7721 cells.

The effects of vitamin E succinate on the expression of c-jun gene and protein in human gastric cancer SGC-7901 cells

AIM

To investigate the effects of vitamin E succinate (VES) on the expression of c-jun gene and protein in human gastric cancer SGC-7901 cells.

METHODS

After SGC-7901 cells were treated with VES at different doses (5,10,20 mg x L(-1)) at different time, reverse transcription-PCR technique was used to detect the level of c-jun mRNA; Western Blot was applied to measure the expression of c-jun protein.

RESULTS

After the cells were treated with VES at 20 mg x L(-1) for 3 h, the expression rapidly reached its maximum that was 3.5 times of UT control (P<0.01). The level of c-jun mRNA was also increased following treatment of VES for 6 h. However,the expression after treatment of VES at 5 mg x L(-1) for 24 h was 1.6 times compared with UT control (P<0.01). Western blot analysis showed that the level of c-jun protein was obviously elevated in VES-treated SGC-7901 cells at 20 mg x L(-1) for 3 h. The expression of c-jun protein was gradually increased after treatment of VES at 20 mg x L(-1) for 3, 6, 12 and 24 h, respectively, with an evident time-effect relationship.

CONCLUSION

The levels of c-jun mRNA and protein in VES-treated SGC-7901 cells were increased in a dose- and time-dependent manner; the expression of c-jun was prolonged by VES, indicating that c-jun is involved in VES-induced apoptosis in SGC-7901 cells.