Stomach cancer highly expresses both initiator and effector caspases; an immunohistochemical study

Potential therapeutic targets of gastric cancer explored under endogenous network modeling of clinical data

Improvement in the survival rate of gastric cancer, a prevalent global malignancy and the leading cause of cancer-related mortality calls for more avenues in molecular therapy. This work aims to comprehend drug resistance and explore multiple-drug combinations for enhanced therapeutic treatment. An endogenous network modeling clinic data with core gastric cancer molecules, functional modules, and pathways is constructed, which is then transformed into dynamics equations for in-silicon studies. Principal component analysis, hierarchical clustering, and K-means clustering are utilized to map the attractor domains of the stochastic model to the normal and pathological phenotypes identified from the clinical data. The analyses demonstrate gastric cancer as a cluster of stable states emerging within the stochastic dynamics and elucidate the cause of resistance to anti-VEGF monotherapy in cancer treatment as the limitation of the single pathway in preventing cancer progression. The feasibility of multiple objectives of therapy targeting specified molecules and/or pathways is explored. This study verifies the rationality of the platform of endogenous network modeling, which contributes to the development of cross-functional multi-target combinations in clinical trials.

The caspase-8 and procaspase-3 expression in gastric cancer and non-cancer mucosa in relation to clinico-morphological factors and some apoptosis-associated proteins

PURPOSE

The aim of the study was to assess the expression of caspase-8 and procaspase-3 proteins in gastric cancer (GC) cells and non-cancerous mucosa in relation to clinical and morphological characteristics of the tumor, postoperative survival as well as other apoptosis-related proteins.

MATERIALS AND METHODS

The study included 91 ​GC patients. Expression of the proteins was assessed using immunohistochemical method.

RESULTS

Positive expression of procaspase-3 was found in all GC cells. A significant difference was found between high expression of this protein in cancer cells (70.3%) and non-cancerous mucosa (1.25%) (p ​≤ ​0.05). Caspase-8 expression was observed in 50.7% of GC cells and 46.7% of mucosa. Caspase-8 was more common in Lauren type II compared to Lauren type I cancer (p ​= ​0.009), while a statistically significant difference was reported between positive procaspase-3 expression and differentiation of GC (p ​= ​0.043) and Lauren's classification (p ​= ​0.028). We observed a significant positive correlation between the expression of caspase-8 and bcl-xl (p ​= ​0.030) as well as between the procaspase-3 and BID (p ​= ​0.026). Positive caspase-8 expression was associated with longer survival of GC patients (p ​≤ ​0.01).

CONCLUSIONS

Our findings indicate the potential role of the analyzed proteins in GC pathogenesis. Positive expression of caspase-8 is associated with longer survival and better patient prognosis.

Effect of photodynamic therapy on expression of HRAS, NRAS and caspase 3 genes at mRNA levels, apoptosis of head and neck squamous cell carcinoma cell line

OBJECTIVES

This study aimed to assess the effect of photodynamic therapy (PDT) on expression of CASP3, NRAS and HRAS genes at mRNA levels, and apoptosis of head and neck squamous cell carcinoma (HNSCC) cell line.

MATERIALS AND METHODS

In order to complete the present in vitro study, HNSCC cell line (NCBI C196 HN5) purchased from Pasteur Institute. Cells were divided into four groups; Group 1: photodynamic treatment (laser + methylene blue (MB) as photosensitizer), group 2: MB, group 3: laser (with 660 nm wavelength), and group 4: control (without any treatment). To determine the optimal concentration of MB, in a pilot study, toxicity of MB in different concentration was assessed using MTT assay. Cells in group 1, 2 and 3 was treated at optimal concentration of MB (1.6 μg/mL). Gene expression at mRNA levels was assessed after 24 h incubation, using real-time (qRT)-PCR. The expression of BAX and BCL2 genes at the mRNA levels was analyzed to evaluate apoptosis. 2^-ΔΔCt values of BCL2, BAX, CASP3, NRAS, and HRAS in groups was analyzed using ANOVA. Tukey's HSD and Games Howell test was used to compare between two groups.

RESULTS

Over-expression of BAX (p < 0.001), CASP3 (p < 0.001) and down-regulation of BCL2 (p = 0.004), HRAS (p = 0.023) and NRAS (p = 0.045) were noted in group 1 (PDT), compared with the control group. Treatment by laser alone induce down-regulation of CASP3 (p < 0.05), BAX (p < 0.05), BCL2 (p > 0.05), HRAS (p > 0.05) and NRAS (p > 0.05).

CONCLUSION

PDT caused down-regulation of NRAS, HRAS and BCL2 and over-expression of CASP3 and BAX genes at mRNA levels in HNSCC cell line. The present study raises the possibility that the role of MB on BCL2 down-regulation and BAX and CASP3 over-expression was higher than laser alone while it seems that laser alone was more effective than MB in HRAS and NRAS down-regulation.

Procaspase-3 Overexpression in Cancer: A Paradoxical Observation with Therapeutic Potential

Many anticancer strategies rely on the promotion of apoptosis in cancer cells as a means to shrink tumors. Crucial for apoptotic function are executioner caspases, most notably caspase-3, that proteolyze a variety of proteins, inducing cell death. Paradoxically, overexpression of procaspase-3 (PC-3), the low-activity zymogen precursor to caspase-3, has been reported in a variety of cancer types. Until recently, this counterintuitive overexpression of a pro-apoptotic protein in cancer has been puzzling. Recent studies suggest subapoptotic caspase-3 activity may promote oncogenic transformation, a possible explanation for the enigmatic overexpression of PC-3. Herein, the overexpression of PC-3 in cancer and its mechanistic basis is reviewed; collectively, the data suggest the potential for exploitation of PC-3 overexpression with PC-3 activators as a targeted anticancer strategy.

Caspase-10, matrix metalloproteinase-9 and total laminin are correlated with the tumor malignancy of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common malignant kidney tumor, the pathogenesis of which remains unclear. The aim of the present study was to investigate whether caspase-10, matrix metalloproteinase-9 (MMP-9) and total laminin (LM) were involved into the pathogenesis of ccRCC. The levels of caspase-10, MMP-9 and total LM were analyzed by ELISA in tumor tissues and adjacent non-malignant tissues of 27 patients with ccRCC. The results revealed that caspase-10 levels in the tumor tissues were significantly higher than those in the adjacent non-malignant tissues (P<0.05). The MMP-9 levels in the tumor tissues were significantly lower than those in adjacent non-malignant tissues (P<0.01). The total LM levels in tumor tissues revealed no statistical difference with those in the adjacent non-malignant tissues (P=0.757). Additionally, caspase-10 levels were positively correlated with MMP-9 levels (P<0.001), but negatively correlated with total LM levels (P<0.05) in tumor tissues. Correlation analyses with clinical data of patients with ccRCC, revealed that caspase-10 levels (P<0.05) and MMP-9 levels (P<0.001) in tumor tissues were positively correlated with tumor grades of ccRCC, whereas total LM levels were positively correlated with tumor size (P<0.05). The results of the present study suggested that interactions between caspase-10, MMP-9 and LM are likely involved in the pathogenesis of ccRCC. A deeper understanding of the correlation between caspase-10, MMP-9 and LM would aid the clarification of pathogenesis of ccRCC.

Expression Analysis of caspase-6, caspase-9 and BNIP3 in Prostate Cancer

Aims

Altered regulation of cell death is a feature of human cancer. The aim of this study was to explore whether the expression of the proapoptotic proteins caspase-6, caspase-9, and Bcl-2/adenovirus E1B-19kDa-interacting protein3 (BNIP3) is altered in prostate cancers.

Methods

We analyzed the expression of caspase-6, caspase-9, and BNIP3 in 107 prostate adenocarcinoma tissues by immunohistochemistry using a tissue microar-ray (TMA) method.

Results

Normal glandular cells expressed caspase-6 and BNIP3 proteins in 10 (9.3%) and 9 (8.4%) prostate tissues, respectively. By contrast, the prostate cancers expressed caspase-6 and BNIP3 in 65 (60.7%) and 69 (64.5%) cases, respectively. Prostate intraepithelial neoplasia (PIN) showed caspase-6 and BNIP3 expression in 65% and 65% of cases, respectively. We observed caspase-9 expression in 40 (37.4%) normal, 8 (40%) PIN, and 45 (42.1%) cancer tissues. None of the expression of caspase-6, caspase-9 or BNIP3 was associated with pathological characteristics such as tumor size, patient age, Gleason score, or tumor stage.

Conclusion

Our data showed that prostate cancer and PIN cells display higher expression of the proapoptotic proteins caspase-6 and BNIP3 than normal cells. Neoexpression of these proteins from the PIN stage suggests that apoptosis deregulation might occur in the early stage of prostate carcinogenesis, and that altered expression of proapoptotic proteins may be a feature of prostate cancer.

Endogenous molecular network reveals two mechanisms of heterogeneity within gastric cancer

Intratumor heterogeneity is a common phenomenon and impedes cancer therapy and research. Gastric cancer (GC) cells have generally been classified into two heterogeneous cellular phenotypes, the gastric and intestinal types, yet the mechanisms of maintaining two phenotypes and controlling phenotypic transition are largely unknown. A qualitative systematic framework, the endogenous molecular network hypothesis, has recently been proposed to understand cancer genesis and progression. Here, a minimal network corresponding to such framework was found for GC and was quantified via a stochastic nonlinear dynamical system. We then further extended the framework to address the important question of intratumor heterogeneity quantitatively. The working network characterized main known features of normal gastric epithelial and GC cell phenotypes. Our results demonstrated that four positive feedback loops in the network are critical for GC cell phenotypes. Moreover, two mechanisms that contribute to GC cell heterogeneity were identified: particular positive feedback loops are responsible for the maintenance of intestinal and gastric phenotypes; GC cell progression routes that were revealed by the dynamical behaviors of individual key components are heterogeneous. In this work, we constructed an endogenous molecular network of GC that can be expanded in the future and would broaden the known mechanisms of intratumor heterogeneity.

Genetic variants in fas signaling pathway genes and risk of gastric cancer

Populations in north central China are at high risk for gastric cancers (GC), and altered FAS-mediated cell signaling and/or apoptosis may contribute to this risk. We examined the association of 554 single nucleotide polymorphisms (SNPs) in 53 Fas signaling-related genes using a pathway-based approach in 1758 GC cases (1126 gastric cardia adenocarcinomas (GCA) and 632 gastric noncardia adenocarcinomas (GNCA)), and 2111 controls from a genome-wide association study (GWAS) of GC in ethnic Chinese. SNP associations with risk of overall GC, GCA and GNCA were evaluated using unconditional logistic regressions controlling for age, sex and study. Gene- and pathway-based associations were tested using the adaptive rank-truncated product (ARTP) method. Statistical significance was evaluated empirically by permutation. Significant pathway-based associations were observed for Fas signaling with risk of overall GC (p = 5.5E-04) and GCA (p = 6.3E-03), but not GNCA (p= 8.1E-02). Among examined genes in the Fas signaling pathway, MAP2K4, FAF1, MAPK8, CASP10, CASP8, CFLAR, MAP2K1, CAP8AP2, PAK2 and IKBKB were associated with risk of GC (nominal p < 0.05), and FAF1 and MAPK8 were significantly associated with risk of both GCA and GNCA (nominal p< 0.05). Our examination of genetic variation in the Fas signaling pathway is consistent with an association of altered Fas signaling and/or apoptosis with risk of GC. As one of the first attempts to investigate a pathway-level association, our results suggest that these genes and the Fas signaling pathway warrant further evaluation in relation to GC risk in other populations.

Adrenomedullin attenuates aortic cross-clamping-induced myocardial injury in rats

BACKGROUND

In this study we investigate the effects of adrenomedullin on myocardial injury after ischemia-reperfusion (I/R) after abdominal aortic surgery.

METHODS

Thirty-two Wistar rats were randomized into 4 groups (n = 8) as follows: control group (sham laparotomy), the aortic I/R group, aortic I/R plus adrenomedullin group (underwent aortic I/R periods, and received a bolus intravenous injection of .05 μg/kg/min adrenomedullin), and the control plus adrenomedullin group.

RESULTS

Biochemical analysis showed that aortic I/R significantly increased (P < .05) the plasma levels of troponin-I and tumor necrosis factor-α, and the myocardial tissue levels of malondialdehyde, superoxide dismutase, catalase, and angiotensin II, whereas aortic I/R plus adrenomedullin significantly decreased these same factors (P < .05). Aortic I/R significantly increased (P < .05) myocardial tissue levels of nitric oxide whereas aortic I/R plus adrenomedullin significantly increased the same factor (P < .05).

CONCLUSIONS

These results indicate that adrenomedullin has protective effects against myocardial injury induced by abdominal aortic I/R in rats.

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.

The enigmatic roles of caspases in tumor development

One function ascribed to apoptosis is the suicidal destruction of potentially harmful cells, such as cancerous cells. Hence, their growth depends on evasion of apoptosis, which is considered as one of the hallmarks of cancer. Apoptosis is ultimately carried out by the sequential activation of initiator and executioner caspases, which constitute a family of intracellular proteases involved in dismantling the cell in an ordered fashion. In cancer, therefore, one would anticipate caspases to be frequently rendered inactive, either by gene silencing or by somatic mutations. From clinical data, however, there is little evidence that caspase genes are impaired in cancer. Executioner caspases have only rarely been found mutated or silenced, and also initiator caspases are only affected in particular types of cancer. There is experimental evidence from transgenic mice that certain initiator caspases, such as caspase-8 and -2, might act as tumor suppressors. Loss of the initiator caspase of the intrinsic apoptotic pathway, caspase-9, however, did not promote cellular transformation. These data seem to question a general tumor-suppressive role of caspases. We discuss several possible ways how tumor cells might evade the need for alterations of caspase genes. First, alternative splicing in tumor cells might generate caspase variants that counteract apoptosis. Second, in tumor cells caspases might be kept in check by cellular caspase inhibitors such as c-FLIP or XIAP. Third, pathways upstream of caspase activation might be disrupted in tumor cells. Finally, caspase-independent cell death mechanisms might abrogate the selection pressure for caspase inactivation during tumor development. These scenarios, however, are hardly compatible with the considerable frequency of spontaneous apoptosis occurring in several cancer types. Therefore, alternative concepts might come into play, such as compensatory proliferation. Herein, apoptosis and/or non-apoptotic functions of caspases may even promote tumor development. Moreover, experimental evidence suggests that caspases might play non-apoptotic roles in processes that are crucial for tumorigenesis, such as cell proliferation, migration, or invasion. We thus propose a model wherein caspases are preserved in tumor cells due to their functional contributions to development and progression of tumors.

Analysis of death receptor 5 and caspase-8 expression in primary and metastatic head and neck squamous cell carcinoma and their prognostic impact

Death receptor 5 (DR5) and caspase-8 are major components in the extrinsic apoptotic pathway. The alterations of the expression of these proteins during the metastasis of head and neck squamous cell carcinoma (HNSCC) and their prognostic impact have not been reported. The present study analyzes the expression of DR5 and caspase-8 by immunohistochemistry (IHC) in primary and metastatic HNSCCs and their impact on patient survival. Tumor samples in this study included 100 primary HNSCC with no evidence of metastasis, 100 primary HNSCC with lymph node metastasis (LNM) and 100 matching LNM. IHC analysis revealed a significant loss or downregulation of DR5 expression in primary tumors with metastasis and their matching LNM compared to primary tumors with no evidence of metastasis. A similar trend was observed in caspase-8 expression although it was not statistically significant. Downregulation of caspase-8 and DR5 expression was significantly correlated with poorly differentiated tumors compared to moderately and well differentiated tumors. Univariate analysis indicates that, in HNSCC with no metastasis, higher expression of caspase-8 significantly correlated with better disease-free survival and overall survival. However, in HNSCC with LNM, higher caspase-8 expression significantly correlated with poorer disease-free survival and overall survival. Similar results were also generated when we combined both DR5 and caspase-8. Taken together, we suggest that both DR5 and caspase-8 are involved in regulation of HNSCC metastasis. Our findings warrant further investigation on the dual role of caspase-8 in cancer development.

Upregulation of caspase-3 expression in esophageal cancer correlates with favorable prognosis: an immunohistochemical study from a high incidence area in northern China

Caspase-3 plays an important role as the key effector during apoptosis, but there are very few studies of caspase-3 in esophageal squamous cell carcinoma (ESCC). The purpose of this study was to investigate the expression and prognostic significance of caspase-3 in ESCC from Linzhou City, a high incidence area in northern China. All 64 patients underwent esophagectomy for ESCC between January 2002 and December were enrolled in this study. Caspase-3 expression was assessed by immunohistochemistry (IHC) in primary ESCC and paired normal esophageal epithelium. The positive rate of caspase-3 expression was higher in ESCC than in normal esophageal epithelium (79.7% vs. 50.0%, Chi-square = 12.372, P= 0.001). Caspase-3 expression was correlated with tumor cell differentiation (Phi = 0.717, P < 0.001), tumor infiltration depth (Phi =-0.334, P= 0.008), and pathologic TNM (pTNM) staging (rs =-0.268, P= 0.032). Patients in caspase-3 positive group had a significantly better 5-year overall survival than those in the negative group (77.4% vs. 35.9%, chi(2)= 7.344, P= 0.007). Our results showed that caspase-3 expression was upregulated in ESCC compared with normal esophageal epithelium in population of Chinese high incidence area, and patients with caspase-3 positive expression had better prognosis. Therefore, caspase-3 immunostaining could be a simple and useful tool for predicting survival in ESCC patients.

Mutational analysis of CASP10 gene in colon, breast, lung and hepatocellular carcinomas

AIMS

Evasion of apoptosis is a feature of cancer cells. As a mechanism of apoptosis inactivation in cancer cells, somatic mutations of pro-apoptotic genes have been reported in many cancers. Caspase-10 is an initiation-phase caspase, and somatic mutation of CASP10 that encodes caspase-10 has been found in non-Hodgkin's lymphoma and gastric carcinoma.

METHODS

The aim of this study was to explore whether CASP10 gene is somatically mutated in colon, breast, lung, and hepatocellular carcinomas. We analysed the entire coding region and all splice sites of CASP10 in 47 colon, 47 breast, 47 lung, and 47 hepatocellular carcinomas by a single-strand conformation polymorphism (SSCP) assay.

RESULTS

We found two CASP10 mutations in the colon cancers (2/47; 4.3%), but none in breast, lung or hepatocellular carcinomas. One mutation [c.41A > C (p.Lys14Thr)] was a missense mutation, while the other was a substitution mutation in a splice site (c.684 + 4G > A). The colon cancer with the CASP10 missense mutation harboured additional CASP gene mutations (CASP3, 7 and 8).

CONCLUSION

Our data indicate that somatic mutation of CASP10 is rare in colon, breast, lung, and hepatocellular carcinomas. However, the data also suggest that CASP10 mutation might contribute to the pathogenesis of some colon carcinomas together with other CASP gene mutations.

Mutational analysis of CASP10 gene in acute leukaemias and multiple myelomas

AIMS

Deregulation of apoptosis is one of the hallmarks of cancers. Inactivation of cancer cell apoptosis by somatic mutations has been reported in several cancers. Caspase-10 activation is important in the initiation phase of apoptosis. The aim of this study was to explore whether CASP10 gene that encodes caspase-10 is somatically mutated in acute adulthood leukaemias and multiple myelomas (MMs).

METHODS

We analysed the entire coding region and all splice sites of CASP10 gene for the detection of somatic mutations in 60 acute leukaemias (25 acute myelogenous leukaemias, 35 acute lymphoblastic leukaemias) and 22 multiple myelomas by a single-strand conformation polymorphism assay.

RESULTS

Overall, we found two CASP10 mutations in the cancers (2/82; 2.4%). One mutation [c.854T>C (pLeu285Pro)] was detected in a T-acute lymphoblastic leukaemia (T-ALL) (1/13 T-ALL; 7.7%). The other mutation [c.61C>T (p.Arg21Cys)] was found in an MM (1/22 MM; 4.5%). The mutations were identified in the coding regions of the death effector domain (p.Arg21Cys) and the p17 large protease subunit (pLeu285Pro). We observed both of the T-ALL and the MM with the CASP10 mutations well expressed the mutant CAS10 at mRNA level.

CONCLUSION

Although our data indicate that somatic mutation of CASP10 is not common in T-ALL and MM, the data suggest a possibility that CASP10 mutation might contribute to the pathogenesis of factions of T-ALL and MM.

Expressional and mutational analysis of pro-apoptotic Bcl-2 member PUMA in hepatocellular carcinomas

Deregulation of apoptosis is involved in mechanisms of cancer development. PUMA is a pro-apoptotic member of the Bcl-2 family and mediates p53-dependent and -independent apoptosis. The aim of this study was to investigate whether alterations of PUMA protein expression and somatic mutations of PUMA gene are characteristics of human hepatocellular carcinoma (HCC). We analyzed expression of PUMA protein in 20 HCCs using immunohistochemistry. Also, we analyzed mutation of the Bcl-2 homology 3 (BH3) domain of PUMA gene, which is an important domain in apoptosis function of PUMA by single-strand conformation polymorphism (SSCP) in 69 HCCs. PUMA protein expression was detected in both HCC cells and non-tumor hepatocytes in all of the 20 HCCs. In 10 of these HCCs, cancer cells showed higher PUMA expression than non-tumor (cirrhotic) hepatocytes of the same patients; whereas in the remaining 10, cancer cells and non-tumor hepatocytes showed similar levels. Mutational analysis revealed no PUMA BH3 domain mutation in the 69 HCCs, suggesting that PUMA BH3 domain mutation is not a direct target of inactivation in hepatocellular cancer development. The increased expression of PUMA in malignant hepatocellular cells relative to that in non-tumor hepatocytes suggests that PUMA expression may play a role in HCC development.

Prognostic value of bax, cytochrome C, and caspase-8 protein expression in primary osteosarcoma

The prognostic significance of bax, cytochrome c, and caspase-8 in patients with primary osteosarcoma is unknown. We examined the immunohistochemical expression of these genes in 35 surgically treated patients with primary osteosarcoma. Clinicopathological and survival data were correlated with the staining result. Eighteen tissue specimens from non-malignant osseous lesions were used as controls. Bax, cytochrome c, and caspase-8 positive staining was observed in 29 (82.9%), 16 (45.7%), and 0 (0%) patients, respectively, but did not stain any of the 18 benign osseous lesions used as controls. None of the genes studied predicted overall or disease-free survival. Patients, however, bearing bax(+)/cytochrome c(+) or bax(+)/cytochrome c(+ +) tumors had a decreased 4-year disease-free survival rate compared to the rest of the group (p = 0.0489 and p = 0.0208, respectively), identifying two groups of patients where more intensive adjuvant treatment could possibly be applied to prevent high postoperative recurrence rates.

Immunohistochemical and mutational analysis of FLASH in gastric carcinomas

FLASH was initially identified as a pro-apoptotic protein that transmits an apoptosis signal during death receptor-induced apoptosis. Additionally, diverse biologic roles of FLASH, including TNF-induced NF-kappaB activation, cell-cycle progression and cell division, have been identified. Although such functions are important in cancer pathogenesis, little is known about the alterations of FLASH gene and FLASH protein expression in human cancers. In this study, we analyzed the expression of FLASH protein in 60 gastric adenocarcinomas by immunohistochemistry. We furthermore analyzed mutation of FLASH in exon 8, where two polyadenine tracts ((A)8 and (A)9) are present, by single-strand conformation polymorphism (SSCP) assay in 184 gastric adenocarcinomas. By immunohistochemistry, FLASH protein expression in cancer cells was detected positively in 42 gastric carcinoma tissues (70%), whereas its expression in epithelial cells of normal gastric mucosa was shown as no or very weak intensity. Mutational analysis detected one FLASH mutation in the gastric carcinomas (0.5%). The increased expression of FLASH in the malignant gastric epithelial cells compared to the normal mucosal epithelial cells suggests that FLASH expression may play a role in gastric tumorigenesis. Also, the data suggest that somatic mutation of FLASH is a rare event in gastric carcinomas.

Immunohistochemical analysis of phospho-BAD protein and mutational analysis of BAD gene in gastric carcinomas

Mounting evidence indicates that deregulation of apoptosis contributes to the development of human cancers. BAD, a proapoptotic Bcl-2 family protein, regulates the intrinsic apoptosis pathway. The aim of this study was to explore whether alterations of phospho-BAD (p-BAD) protein that antagonizes apoptosis function of BAD and mutation of BAD gene are characteristics of human gastric cancers. We analyzed expression of p-BAD in 60 gastric adenocarcinomas by immunohistochemistry. Also, we analyzed BAD gene for detection of somatic mutations by single-strand conformation polymorphism (SSCP) assay. p-BAD expression was detected well in normal gastric mucosal epithelial cells, whereas it was detected in only 51% (31 of the 60) of the cancers. There was no somatic mutation of BAD gene in the 60 gastric cancer samples. The decreased expression of p-BAD in malignant gastric epithelial cells compared to normal mucosal epithelial cells suggested that loss of p-BAD expression may play a role in gastric tumorigenesis. The data also suggest that BAD mutation may not be a direct target of inactivation in gastric tumorigenesis.

Effects of leptin on stress-induced changes of caspases in rat gastric mucosa

BACKGROUND

In this study, we investigated the effect of leptin on caspase-3, caspase-8, and caspase-9 immunoreactivity and lipid peroxidation in the stomachs of rats exposed to cold-restraint stress.

METHODS

Thirty-two male Wistar Albino rats were used. Rats pretreated with leptin (10 microg/kg per day for 7 days) were restrained in a wire cage for 4 h at 4 degrees C. Spectrophotometric techniques were used for detection of malondialdehyde (MDA) and glutathione (GSH) levels, and immunoreactivity of caspases was investigated by immunohistochemistry.

RESULTS

While the stomach MDA level of the cold-restraint stress group was increased significantly, the level of GSH was decreased when compared with the control group. Caspase-9 and caspase-3 immunoreactivities of the stress group were not changed, while caspase-8 immunoreactivity was decreased. Leptin administration prevented the increase in the MDA level and the decrease in the GSH content of the gastric mucosa in animals subjected to stress. Leptin administration produced no significant change in caspase-8 immunoreactivity but caused a decrease in caspase-3 immunoreactivity.

CONCLUSIONS

Cold-restraint stress decreases the antioxidant capacity of stomach tissue while activating oxidants, and induces apoptosis by an increase in caspase immunoreactivity. The presence of leptin reverses these mechanisms and suppresses the apoptosis.

Expression of phosphorylated caspase-9 in gastric carcinomas

Alterations of caspases, the main executioners of apoptosis, have been described in human cancers. Caspase-9 plays a crucial role in the initiation phase of the intrinsic apoptosis pathway. Caspase-9 is phosphorylated at Thr125 through the mitogen-activated protein kinase (MAPK) pathway, and this phosphorylation is associated with inhibition of caspase-9 activation. The aim of this study was to explore whether phosphorylated caspase-9 (p-caspase-9) expression could be a characteristic of gastric carcinomas. We analyzed expression of p-caspase-9 protein in 60 gastric adenocarcinomas by immunohistochemistry using a tissue microarray approach. p-caspase-9 was detected in 33 of the 60 carcinomas (55%). Both early and advanced gastric carcinomas expressed p-caspase-9. There was no significant association of p-caspase-9 expression with clinocopathological characteristics, including invasion, metastasis and stage. In contrast to gastric cancer cells, epithelial cells in normal gastric mucosa showed no or only weak expression of p-caspase-9. Taken together, these results indicate that caspase-9 is frequently phosphorylated in gastric carcinomas, and that the phosphorylation of caspase-9 might be an inhibitory mechanism of caspase-9-mediated apoptosis in gastric carcinomas. Increased expression of p-caspase-9 in malignant gastric epithelial cells compared to normal mucosal epithelial cells suggests that p-caspase-9 expression might play a role in gastric carcinoma development.

Immunohistochemical analysis of pro-apoptotic PUMA protein and mutational analysis of PUMA gene in gastric carcinomas

BACKGROUND

Mounting evidence indicates that alteration of apoptosis is involved in the mechanisms of cancer development. PUMA, a pro-apoptotic member of Bcl-2 family, mediates p53-dependent and -independent apoptosis.

AIM

The aim of this study was to explore whether alteration of PUMA protein expression is a characteristic of human gastric carcinomas.

PATIENTS AND METHODS

We analysed expression of PUMA protein in 60 gastric adenocarcinomas by immunohistochemistry. Also, we examined PUMA gene mutation in the same tissues by a single-strand conformation polymorphism.

RESULTS

PUMA protein expression was detected in 44 cases (73%) of the 60 gastric carcinomas, whereas it was not detected in normal gastric mucosal epithelial cells. The mutational analysis revealed no PUMA mutation in the gastric carcinomas.

CONCLUSIONS

Our data suggest that PUMA mutation is not a direct target of inactivation in gastric tumourigenesis. Also, increased expression of PUMA in malignant gastric epithelial cells compared with normal mucosal epithelial cells suggested that PUMA expression may play a role in gastric tumourigenesis.

Immunohistochemical and mutational analysis of apoptosis-inducing factor (AIF) in colorectal carcinomas

Apoptosis-inducing factor (AIF) has a principal role in caspase-independent apoptosis. In addition, AIF has a vital oxidoreductase activity that is required for cell survival. It may be important to identify the alterations of the AIF gene and AIF protein expression to see the function of AIF in human cancers. In this study we analyzed the expression of AIF protein in 103 colorectal carcinomas by immunohistochemistry. We also analyzed the mutation in exons 10-15 of AIF encoding the region that possesses the cell death function of AIF by single-strand conformation polymorphism (SSCP) in 48 colorectal, 48 gastric, 48 breast and 48 hepatocellular carcinomas, and 48 leukemias. By immunohistochemistry, AIF protein expression was detected in both cancer cells and normal mucosal epithelial cells in all of the 103 colorectal carcinoma tissues. However, the cancer cells showed higher intensities of AIF immunostaining than the normal cells in 83 cases (80.5%). AIF immunoreactivities were observed in the cancers irrespective of their location or the depth of invasion. Mutational analysis detected one AIF mutation in the colorectal carcinomas, but none in the other cancers. The AIF mutation detected was a two-base deletion mutation in intron 15. The increased expression of AIF in the malignant colorectal epithelial cells compared to the normal mucosal epithelial cells suggests that AIF expression may play a role in colorectal tumorigenesis. The data also suggest that somatic mutation of AIF is a rare event in common human cancers.

Immunohistochemical analysis of apoptosis-inducing factor (AIF) expression in gastric carcinomas

Mounting evidence suggests that both survival and death of cells play an important role in tumorigenesis. Apoptosis-inducing factor (AIF), a mitochondrial protein, plays an important role in the caspase-independent apoptosis. Also, recent studies have demonstrated that AIF has an oxidoreductase function that confers survival on the cells. As the roles of AIF in cancers are largely unknown, it may be important to identify the expression pattern of AIF in cancer tissues. In this study, which aims at defining the role of AIF in gastric tumorigenesis, we analyzed the expression of AIF in 60 gastric adenocarcinomas using immunohistochemistry. AIF expression was detected in the cytoplasm in 42 cases (70%) of gastric carcinoma. We also analyzed AIF expression in early (EGC) and advanced gastric carcinomas (AGC). AIF was expressed in 25 (73%) of 34 intestinal-type cancers and in 17 (65%) of 26 diffuse-type cancers. However, there was no significant difference in AIF expression with respect to the histological subtypes or the depth of invasions, either. In normal gastric mucosal cells, parietal cells, but not other mucosal cells, expressed AIF. Increased expression of AIF in malignant gastric epithelial cells compared to the normal mucosal cells suggests that AIF expression may play a role in gastric tumorigenesis. Also, the data suggest that AIF expression may play a role in the function of the gastric parietal cells.

Differential caspase-3 expression in noncancerous, premalignant and cancer tissues of stomach and its clinical implication

BACKGROUND

Caspase-3 is a critical apoptosis-promoting element but its status during stepwise gastrocarcinogenesis needs to be further clarified.

MATERIALS AND METHODS

By the use of frozen tissue microarrays constructed with the tissue spots cored from defined histological regions in tissue blocks, the pattern of caspase-3 expression in noncancerous, premalignant (atrophic gastritis and intestinal metaplasia) tissue and cancer spots were analyzed under the same experimental conditions by the methods of immunohistochemistry and mRNA-in situ hybridization.

RESULTS

Caspase-3 was expressed in all 34 of the noncancerous mucosa (100%), in 16 of the 17 premalignant tissues (94.1%) and in 15 of the 48 gastric cancers (31.3%). The incidences of caspase-3 detection were significantly different (p<0.01) between noncancerous mucosa and intestinal as well as diffuse gastric cancers.

CONCLUSION

Down-regulated caspase-3 is closely correlated with gastric cancer formation and would be a potential indicator of tumor formation and progression. Helicobacter pylori (H. pylori; Hp) infection is but not the only one element responsible to the enhanced caspase-3 expression in gastric epithelia.

TC-1 is a novel tumorigenic and natively disordered protein associated with thyroid cancer

A novel gene, thyroid cancer 1 (TC-1), was found recently to be overexpressed in thyroid cancer. TC-1 shows no homology to any of the known thyroid cancer-associated genes. We have produced stable transformants of normal thyroid cells that express the TC-1 gene, and these cells show increased proliferation rates and anchorage-independent growth in soft agar. Apoptosis rates also are decreased in the transformed cells. We also have expressed recombinant TC-1 protein and have undertaken a structural and functional characterization of the protein. The protein is monomeric and predominantly unstructured under conditions of physiologic salt and pH. This places it in the category of natively disordered proteins, a rapidly expanding group of proteins, many members of which play critical roles in cell regulation processes. We show that the protein can be phosphorylated by cyclic AMP-dependent protein kinase and protein kinase C, and the activity of both of these kinases is up-regulated when cells are stably transfected with TC-1. These results suggest that overexpression of TC-1 may be important in thyroid carcinogenesis.

Loss of caspase-2, -6 and -7 expression in gastric cancers

Female adnexal tumor of probable Wolffian origin (FATWO) is a rare entity which is believed to originate from mesonephric (Wolffian) remnants on the basis of its location where the remnants are abundant. Its behavior is usually indolent, although some cases can recur or metastasize. The authors present the clinicopathological features of two cases of FATWO arising in the broad ligament, and focus on the expression of adhesion molecules and proliferative marker. Mesonephric duct remnants are also examined in an attempt to elucidate the histogenesis of FATWOs. The two FATWOs were well-circumscribed solid masses arising in the leaves of the broad ligament and histological examination revealed a mixture of cysts and tubules imparting a sieve-like pattern and mucin-negative eosinophilic secretion within these tubules. Immunohistochemically, the tumors showed the expression of cytokeratin 7 and 20, high-molecular-weight cytokeratin, and calretinin, which closely resembled that of the mesonephric duct remnants. Regarding CK 20, CD 10, EMA, S-100 protein, and vimentin their expression was in part not identical with previous studies. E-cadherin, alpha and beta-catenin were strongly expressed along the cell membrane of the tumor cells. The Ki-67 labeling index of FATWO was 0% and 3.2% in each case. The preservation of the E-cadherin-catenin complex and low Ki-67 labeling index could explain the indolent behavior and low malignant potential of this tumor.