Protective Role of Spermidine in Colitis and Colon Carcinogenesis

BACKGROUND & AIMS

Because inflammatory bowel disease is increasing worldwide and can lead to colitis-associated carcinoma (CAC), new interventions are needed. We have shown that spermine oxidase (SMOX), which generates spermidine (Spd), regulates colitis. Here we determined whether Spd treatment reduces colitis and carcinogenesis.

METHODS

SMOX was quantified in human colitis and associated dysplasia using quantitative reverse-transcription polymerase chain reaction and immunohistochemistry. We used wild-type (WT) and Smox-/- C57BL/6 mice treated with dextran sulfate sodium (DSS) or azoxymethane (AOM)-DSS as models of colitis and CAC, respectively. Mice with epithelial-specific deletion of Apc were used as a model of sporadic colon cancer. Animals were supplemented or not with Spd in the drinking water. Colonic polyamines, inflammation, tumorigenesis, transcriptomes, and microbiomes were assessed.

RESULTS

SMOX messenger RNA levels were decreased in human ulcerative colitis tissues and inversely correlated with disease activity, and SMOX protein was reduced in colitis-associated dysplasia. DSS colitis and AOM-DSS-induced dysplasia and tumorigenesis were worsened in Smox-/- vs WT mice and improved in both genotypes with Spd. Tumor development caused by Apc deletion was also reduced by Spd. Smox deletion and AOM-DSS treatment were both strongly associated with increased expression of α-defensins, which was reduced by Spd. A shift in the microbiome, with reduced abundance of Prevotella and increased Proteobacteria and Deferribacteres, occurred in Smox-/- mice and was reversed with Spd.

CONCLUSIONS

Loss of SMOX is associated with exacerbated colitis and CAC, increased α-defensin expression, and dysbiosis of the microbiome. Spd supplementation reverses these phenotypes, indicating that it has potential as an adjunctive treatment for colitis and chemopreventive for colon carcinogenesis.

Induction of Gastric Cancer by Successive Oncogenic Activation in the Corpus

BACKGROUND & AIMS

Metaplasia and dysplasia in the corpus are reportedly derived from de-differentiation of chief cells. However, the cellular origin of metaplasia and cancer remained uncertain. Therefore, we investigated whether pepsinogen C (PGC) transcript-expressing cells represent the cellular origin of metaplasia and cancer using a novel Pgc-specific CreERT2 recombinase mouse model.

METHODS

We generated a Pgc-mCherry-IRES-CreERT2 (Pgc-CreERT2) knock-in mouse model. Pgc-CreERT2/+ and Rosa-EYFP mice were crossed to generate Pgc-CreERT2/Rosa-EYFP (Pgc-CreERT2/YFP) mice. Gastric tissues were collected, followed by lineage-tracing experiments and histologic and immunofluorescence staining. We further established Pgc-CreERT2;KrasG12D/+ mice and investigated whether PGC transcript-expressing cells are responsible for the precancerous state in gastric glands. To investigate cancer development from PGC transcript-expressing cells with activated Kras, inactivated Apc, and Trp53 signaling pathways, we crossed Pgc-CreERT2/+ mice with conditional KrasG12D, Apcflox, Trp53flox mice.

RESULTS

Expectedly, mCherry mainly labeled chief cells in the Pgc-CreERT2 mice. However, mCherry was also detected throughout the neck cell and isthmal stem/progenitor regions, albeit at lower levels. In the Pgc-CreERT2;KrasG12D/+ mice, PGC transcript-expressing cells with KrasG12D/+ mutation presented pseudopyloric metaplasia. The early induction of proliferation at the isthmus may reflect the ability of isthmal progenitors to react rapidly to Pgc-driven KrasG12D/+ oncogenic mutation. Furthermore, Pgc-CreERT2;KrasG12D/+;Apcflox/flox mice presented intramucosal dysplasia/carcinoma and Pgc-CreERT2;KrasG12D/+;Apcflox/flox;Trp53flox/flox mice presented invasive and metastatic gastric carcinoma.

CONCLUSIONS

The Pgc-CreERT2 knock-in mouse is an invaluable tool to study the effects of successive oncogenic activation in the mouse corpus. Time-course observations can be made regarding the responses of isthmal and chief cells to oncogenic insults. We can observe stomach-specific tumorigenesis from the beginning to metastatic development.

Pyruvate Kinase M2 Expression: A Potential Metabolic Biomarker to Differentiate Endometrial Precancer and Cancer That Is Associated with Poor Outcomes in Endometrial Carcinoma

Background: Pyruvate kinase M2 (PKM2) is a regulator of the processes of glycolysis and oxidative phosphorylation, but the roles that it plays in endometrial cancer remain largely unknown. This study evaluated the PKM2 expression in normal endometrium, endometrial hyperplasia, and endometrial carcinoma, and its prognostic value was investigated in endometrial carcinoma patients. Methods: A hospital-based retrospective review was conducted to examine the immunohistochemical PKM2 distribution in 206 endometrium samples from biopsies or hysterectomies. The immunoreactivity of PKM2 was divided into groups of low and high scores according to the extent and intensity of staining. Results: Intense cytoplasmic staining was observed for the PKM2 protein in malignant endometrial lesions. A high PKM2 score was observed in many endometrial carcinoma samples (50.0%), but there was a low percentage in endometrial atypical hyperplasia (12.5%). High PKM2 expression was not found in the normal endometrium (0.0%) nor endometrial hyperplasia without atypia (0.0%). The PKM2 protein score was significantly higher in endometrial carcinoma samples than premalignant endometrial lesions (p < 0.001). Notably, higher PKM2 scores in cases of endometrial carcinoma correlated with poor overall survival (p = 0.006), and the hazard ratio for death was 3.40 (95% confidence interval, 1.35–8.56). Conclusions: Our results indicate that the prevalence of PKM2^high tumor cells in endometrial carcinoma is significantly associated with worse prognostic factors and favors a poor prognosis. The expression of PKM2 is also a potential histopathological biomarker for use in the differential diagnosis of malignant and premalignant endometrial lesions.

Thymidine phosphorylase and angiogenesis in early stage esophageal squamous cell carcinoma

BACKGROUND

The relationship between thymidine phosphorylase (TP) and angiogenesis at the early stage of esophageal squamous cell carcinoma has been unclear.

METHODS

Using 14 samples of normal squamous epithelium, 11 samples of low-grade intraepithelial neoplasia, and 64 samples of superficial esophageal cancer, microvessel density (MVD) was estimated using immunostaining for CD34 and CD105. TP expression was also evaluated in both cancer cells and stromal monocytic cells (SMCs). We then investigated the correlation between MVD and TP expression in both cancer cells and SMCs.

RESULTS

On the basis of the above parameters, MVD was significantly higher in cancerous lesions than in normal squamous epithelium. In terms of CD34 and CD105 expression, MVD showed a gradual increase from normal squamous epithelium, to low-grade intraepithelial neoplasia, and then to M1 and M2 cancer, and M3 or deeper cancer. M1 and M2 cancer showed overexpression of TP in both cancer cells and SMCs. There was no significant correlation between TP expression in cancer cells and MVD estimated from CD34 (rS = 0.16, P = 0.21) or CD105 (rS = 0.05, P = 0.68) expression. Significant correlations were found between TP expression in SMCs and CD34-related (rS = 0.46, P < 0.001) and CD105-related (rS = 0.34, P < 0.01) MVD. In M3 or deeper cancers, there were no significant correlations between TP expression in cancer cells or SMCs and venous invasion, lymphatic invasion, and lymph node metastasis.

CONCLUSION

TP expression is activated in both cancer cells and stromal monocytic cells at the very early stage of ESCC progression. TP expression in SMCs, rather than in cancer cells, is significantly correlated with angiogenesis.

Molecular profiles of benign and (pre)malignant endometrial lesions

Endometrial carcinomas are histologically classified as endometrioid, assumed to originate from hyperplastic endometrium, or non-endometrioid carcinomas, assumed to originate from atrophic endometrium. However, both on a histological and a molecular level there are indications that there are more carcinoma types and carcinogenetic pathways. This study aims to analyze endometrial carcinogenesis on a molecular level. The presence of known KRAS, PIK3CA, AKT1, CTNNB1, BRAF, EGFR and NRAS mutations was studied in proliferative, atrophic and hyperplastic endometrium, endometrioid and serous carcinomas, and the endometrium next to these carcinomas, using single molecule Molecular Inversion Probes. Mutations were found in 9 (15%) of the 62 non atypical, and in 6 (18%) of the 34 atypical hyperplasia cases. In comparison, mutations were found in 1 (3%) of the simple, and 8 (30%) of the 27 complex hyperplasia cases. In 12/22 (55%) endometrioid carcinomas, a mutation was found. The KRAS gene was most often mutated in carcinomas next to hyperplastic endometrium, whereas PIK3CA and CTNNB1 mutations were found in endometrioid carcinomas with adjacent atrophic endometrium. Complex hyperplasia rather than atypical hyperplasia appears to be the most important lesion in the carcinogenesis of endometrioid carcinomas, and KRAS, PIK3CA and CTNNB1 mutations appear to play an important role in this process. Carcinogenesis of endometrioid carcinomas next to hyperplasia seems to be different to that of those next to atrophia. The value of these findings in managing endometrial hyperplasia and carcinoma should be studied.

Involvement of Activated Cdc42 Kinase1 in Colitis and Colorectal Neoplasms

BACKGROUND Activated Cdc42 kinase1 (ACK1) is a non-receptor tyrosine kinase which is critical for cell survival, proliferation, and migration. Genomic amplification of ACK1 has been reported in multiple human cancers. We aimed to investigate ACK1 protein expression in colorectal mucosa with inflammation and neoplasm, and to evaluate its correlation with disease activity and severity. MATERIAL AND METHODS A total of 250 individuals who underwent total colonoscopy were collected randomly from January 2007 to May 2013 in Nanfang Hospital, Guangzhou, China. Colorectal mucosal biopsy specimens were obtained by endoscopy from 78 patients with ulcerative colitis (UC), 22 with Crohn's disease (CD), 20 with infectious colitis, 26 with non-IBD and noninfectious colitis, 16 with sporadic adenomas, 4 with dysplasia-associated lesions or masses, 10 with sporadic colorectal cancer (CRC), 4 with UC-related CRC, 10 with hyperplastic polyps, and 60 without colonic abnormalities. ACK1 protein levels were determined immunohistochemically. The correlations of ACK1 expression with disease activity and severity were also evaluated. RESULTS Significantly increased ACK1 expression was observed in epithelial cells of colorectal mucosa with inflammation and dysplasia compared to controls (P<0.05). ACK1 expression correlated with clinical activity in IBD (χ²=4.57, P=0.033 for UC; χ²=5.68, P=0.017 for CD), as well as grade of dysplasia in preneoplastic lesions (P<0.05). No significant differences in ACK1 expression were found between UC and CD, or between IBD and non-IBD conditions (P>0.05). CONCLUSIONS ACK1 protein is increased extensively in colitis and colorectal dysplasia. ACK1 overexpression may play a role in colorectal inflammation and neoplasms.

Everything you always wanted to know about GIST (but were afraid to ask) An update on GIST pathology

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The discovery of the occurrence of activating KIT mutations and KIT expression in GISTs opened the way to the unequivocal diagnosis of these tumors and to their successful treatment with imatinib, a tyrosin kinase inhibitor. Since then, research progress revealed molecular GIST triggers alternative to KIT, implying heterogeneous analytic approaches and prognostic expectations. Several targeted therapies, variably specific for each GIST trigger, have been developed or are being investigated. Thus, GISTs eventually revealed a family of diseases rather than a single tumor type. All these events had an unprecedented impact on pathology practice, constituting at the same time a heavy burden and an exciting challenge, ultimately putting pathologists in the spotlight as never before. This review will discuss the most recent advances concerning GISTs, highlighting the tasks of pathologists facing these tumors, with an emphasis on traps potentially compromising a correct diagnosis.

The Role of Indoleamine 2,3-Dioxygenase in Diethylnitrosamine-Induced Liver Carcinogenesis

Indoleamine 2,3-dioxygenase (IDO), a tryptophan-catabolizing intracellular enzyme of the L-kynurenine pathway, causes preneoplastic cells and tumor cells to escape the immune system by inducing immune tolerance; this mechanism might be associated with the development and progression of human malignancies. In the present study, we investigated the role of IDO in diethylnitrosamine (DEN)-induced hepatocarcinogenesis by using IDO-knockout (KO) mice. To induce hepatocellular carcinoma (HCC), hepatic adenoma, and preneoplastic hepatocellular lesions termed foci of cellular alteration (FCA), male IDO-wild-type (WT) and IDO-KO mice with a C57BL/6J background received a single intraperitoneal injection of DEN at 2 weeks of age. The mice were sacrificed to evaluate the development of FCA and hepatocellular neoplasms. HCC overexpressed IDO and L-kynurenine compared to surrounding normal tissue in the DEN-treated IDO-WT mice. The number and cell proliferative activity of FCAs, and the incidence and multiplicity of HCC were significantly greater in the IDO-WT than in the IDO-KO mice. The expression levels of the IDO protein, of L-kynurenine, and of IFN-γ, COX-2, TNF-α, and Foxp3 mRNA were also significantly increased in the DEN-induced hepatic tumors that developed in the IDO-WT mice. The mRNA expression levels of CD8, perforin and granzyme B were markedly increased in hepatic tumors developed in IDO-KO mice. Moreover, Foxp3-positive inflammatory cells had infiltrated into the livers of DEN-treated IDO-WT mice, whereas fewer cells had infiltrated into the livers of IDO-KO mice. Induction of IDO and elevation of L-kynurenine might play a critical role in both the early and late phase of liver carcinogenesis. Our findings suggest that inhibition of IDO might offer a promising strategy for the prevention of liver cancer.

Nitric oxide synthase evaluation in oral precancerous and cancerous lesions

Nitric Oxide (NO) has been linked to several cardiovascular, neurological and immunological physiological and pathological functions. Several studies have shown that the eNOS, nNOS and iNOS effects on cancer cell growth and proliferation are related to the upregulation of the Wnt pathway and have a central role during metastasis development. Recent studies suggest that cancer cells undergo metabolic reprogramming, which drives cancer cell growth and progression. The aim of this study was to observe the NOS activity in the pathogenesis of oral precancerous and cancerous lesions. The results showed changes in eNOS activity levels, which increased from healthy oral mucosa to oral squamous cell carcinoma SCC, through different dysplasia levels. The iNOS activity levels increased in precancerous lesions compared to healthy mucosa, where iNOS was absent, while it decreased in SCC lesions. Moreover, a gradual increase of nNOS activity together with the progression of the lesions was also found. These results may suggest how NO could play a critical role during pathogenesis, growth and development of precancerous lesions to cancer degeneration.

Activation of EGFR and ERBB2 by Helicobacter pylori results in survival of gastric epithelial cells with DNA damage

BACKGROUND & AIMS

The gastric cancer-causing pathogen Helicobacter pylori up-regulates spermine oxidase (SMOX) in gastric epithelial cells, causing oxidative stress-induced apoptosis and DNA damage. A subpopulation of SMOX(high) cells are resistant to apoptosis, despite their high levels of DNA damage. Because epidermal growth factor receptor (EGFR) activation can regulate apoptosis, we determined its role in SMOX-mediated effects.

METHODS

SMOX, apoptosis, and DNA damage were measured in gastric epithelial cells from H. pylori-infected Egfr(wa5) mice (which have attenuated EGFR activity), Egfr wild-type mice, or in infected cells incubated with EGFR inhibitors or deficient in EGFR. A phosphoproteomic analysis was performed. Two independent tissue microarrays containing each stage of disease, from gastritis to carcinoma, and gastric biopsy specimens from Colombian and Honduran cohorts were analyzed by immunohistochemistry.

RESULTS

SMOX expression and DNA damage were decreased, and apoptosis increased in H. pylori-infected Egfr(wa5) mice. H. pylori-infected cells with deletion or inhibition of EGFR had reduced levels of SMOX, DNA damage, and DNA damage(high) apoptosis(low) cells. Phosphoproteomic analysis showed increased EGFR and erythroblastic leukemia-associated viral oncogene B (ERBB)2 signaling. Immunoblot analysis showed the presence of a phosphorylated (p)EGFR-ERBB2 heterodimer and pERBB2; knockdown of ErbB2 facilitated apoptosis of DNA damage(high) apoptosis(low) cells. SMOX was increased in all stages of gastric disease, peaking in tissues with intestinal metaplasia, whereas pEGFR, pEGFR-ERBB2, and pERBB2 were increased predominantly in tissues showing gastritis or atrophic gastritis. Principal component analysis separated gastritis tissues from patients with cancer vs those without cancer. pEGFR, pEGFR-ERBB2, pERBB2, and SMOX were increased in gastric samples from patients whose disease progressed to intestinal metaplasia or dysplasia, compared with patients whose disease did not progress.

CONCLUSIONS

In an analysis of gastric tissues from mice and patients, we identified a molecular signature (based on levels of pEGFR, pERBB2, and SMOX) for the initiation of gastric carcinogenesis.

Bile acid increases expression of the histamine-producing enzyme, histidine decarboxylase, in gastric cells

AIM: To investigate the effect of bile acid on the expression of histidine decarboxylase (HDC), which is a major enzyme involved in histamine production, and gene expression of gastric transcription factors upon cooperative activation.

METHODS: HDC expression was examined by immunohistochemistry, reverse transcriptase polymerase chain reaction, and promoter assay in human gastric precancerous tissues, normal stomach tissue, and gastric cancer cell lines. The relationship between gastric precancerous state and HDC expression induced by bile acid was determined. The association between the expression of HDC and various specific transcription factors in gastric cells was also evaluated. MKN45 and AGS human gastric carcinoma cell lines were transfected with farnesoid X receptor (FXR), small heterodimer partner (SHP), and caudal-type homeodomain transcription factor (CDX)1 expression plasmids. The effects of various transcription factors on HDC expression were monitored by luciferase-reporter promoter assay.

RESULTS: Histamine production and secretion in the stomach play critical roles in gastric acid secretion and in the pathogenesis of gastric diseases. Here, we show that bile acid increased the expression of HDC, which is a rate-limiting enzyme of the histamine production pathway. FXR was found to be a primary regulatory transcription factor for bile acid-induced HDC expression. In addition, the transcription factors CDX1 and SHP synergistically enhanced bile acid-induced elevation of HDC gene expression. We confirmed similar expression patterns for HDC, CDX1, and SHP in patient tissues.

CONCLUSION: HDC production in the stomach is associated with bile acid exposure and its related transcriptional regulation network of FXR, SHP, and CDX1.

Deletion of glutathione peroxidase-2 inhibits azoxymethane-induced colon cancer development

The selenoprotein glutathione peroxidase-2 (GPx2) appears to have a dual role in carcinogenesis. While it protected mice from colon cancer in a model of inflammation-triggered carcinogenesis (azoxymethane and dextran sodium sulfate treatment), it promoted growth of xenografted tumor cells. Therefore, we analyzed the effect of GPx2 in a mouse model mimicking sporadic colorectal cancer (azoxymethane-treatment only). GPx2-knockout (KO) and wild-type (WT) mice were adjusted to an either marginally deficient (−Se), adequate (+Se), or supranutritional (++Se) selenium status and were treated six times with azoxymethane (AOM) to induce tumor development. In the −Se and ++Se groups, the number of tumors was significantly lower in GPx2-KO than in respective WT mice. On the +Se diet, the number of dysplastic crypts was reduced in GPx2-KO mice. This may be explained by more basal and AOM-induced apoptotic cell death in GPx2-KO mice that eliminates damaged or pre-malignant epithelial cells. In WT dysplastic crypts GPx2 was up-regulated in comparison to normal crypts which might be an attempt to suppress apoptosis. In contrast, in the +Se groups tumor numbers were similar in both genotypes but tumor size was larger in GPx2-KO mice. The latter was associated with an inflammatory and tumor-promoting environment as obvious from infiltrated inflammatory cells in the intestinal mucosa of GPx2-KO mice even without any treatment and characterized as low-grade inflammation. In WT mice the number of tumors tended to be lowest in +Se compared to −Se and ++Se feeding indicating that selenium might delay tumorigenesis only in the adequate status. In conclusion, the role of GPx2 and presumably also of selenium depends on the cancer stage and obviously on the involvement of inflammation.

Effect of methylxanthines (coffee/tea consumers) on oral precancer and oral cancer patients with smoking and smokeless tobacco habits

AIM

To study, whether the consumption of regular tea/coffee (methylxanthines) increases the risk of oral cancer in patients with smoking and smokeless tobacco habits.

MATERIALS AND METHODS

This study was conducted on a total of 90 oral cancer and precancerous patients, from western Maharashtra (India) males in the age group of 20 to 45 years who were with smoking and smokeless tobacco habits; also regular tea/coffee consumers were subjected to biochemical parameters such as aspartate transaminase (AST) and alanine transaminase (ALT) from saliva and serum of patients with oral precancer (submucous fibrosis, leukoplakia) and oral cancer patients and compared with 90-age and sex-matched controls. Individuals consent was taken to measure their biochemical parameters, by using Hafkenscheid method in whole saliva and serum. Statistical analysis of variance (ANOVA) with Tukey's correction for multiple group comparisons was performed using Student t-test.

RESULTS

Results show, that a statistically significant increase in value (p < 0.05) in ALT, AST in both saliva and serum was observed in precancerous and oral cancer patients among the study group as compared to the control group.

CONCLUSION

In the present study, there was increase in the levels of ALT, AST enzymes in both saliva and serum levels in the study group as compared to the control group which was statistically significant (p < 0.05) suggesting that long-term exposure of methylxanthines results in impairment of salivary gland antioxidant system which may affect the anticarcinogenic action of saliva.

CLINICAL SIGNIFICANCE

Oral fluids may be utilized effectively to study the variations in the biochemical constituents of saliva of leukoplakia, submucous fibrosis and oral cancer patients.

The inactive form of glycogen synthase kinase-3β is associated with the development of carcinomas in galectin-3 wild-type mice, but not in galectin-3-deficient mice

Galectin-3 has been implicated in the tumor development via its mediation of the Wnt signaling pathway. Likewise, glycogen synthase kinase-3beta (GSK3β) also plays a role in the Wnt signaling pathway by controlling the levels of cytoplasmic beta-catenin. Altered GSK3β expression has been described in various tumors, but to date, there are no studies evaluating its expression in models of oral carcinogenesis. Additionally, it is unknown whether the absence of galectin-3 regulates the expression of GSK3β. To this end, Gal3-deficient (Gal3(-/-)) and wild-type (Gal3(+/+)) male mice were treated with 4NQO for 16 weeks and sacrificed at week 16 and 32. The tongues were removed, processed, and stained with H&E to detect dysplasias and carcinomas. An immunohistochemical assay was performed to determine the level of P-GSK3β-Ser9 expression in both groups. Carcinomas were more prevalent in Gal3(+/+) than Gal3(-/-) mice (55.5% vs. 28.5%), but no statistical difference was reached. In the dysplasias, the proportion of cells positive for P-GSK3β-Ser9 was slightly higher in Gal3(+/+) than Gal3(-/-) mice (63% vs. 61%). In the carcinomas, a significant difference between Gal3(+/+) and Gal3(-/-) mice was found (74% vs. 59%; p=0.02). P-GSK3β-Ser9-positive cells slightly decreased from the progression of dysplasias to carcinomas in Gal3(-/-) mice (61% vs. 59%; p>0.05). However, a significant increase in P-GSK3β-Ser9 expression was observed from dysplasias to carcinomas in Gal3(+/+) mice (63% vs. 74%; p=0.01). In conclusion, these findings suggest that fully malignant transformation of the tongue epithelium is associated with increased P-GSK3β-Ser9 expression in Gal3(+/+) mice, but not in Gal3(-/-) mice.

Co-expression of metalloproteinases 11 and 12 in cervical scrapes cells from cervical precursor lesions

The metalloproteinases (MMP) 11 and 12 have been shown to be expressed in cervical cancer (CC). In order to extend our previous results, these MMPs were evaluated in cervical precursor lesions. One hundred seventeen cervical scrapes: thirty-six normal, thirty-six low grade squamous lesions (LSIL), thirty-six high grade (HSIL), nine CC; and, also ninety-nine paraffin-embedded cervical lesions: fifteen normal cervices, thirty eight LSIL, sixteen HSIL, and five CC were collected. The samples were analyzed for relative expression by real time RT-PCR or immunohistochemistry assay. We were able to identify a relative increased expression of MMP11 in 75% and 78% from LSIL and HSIL samples, respectively. While MMP12 expression was 64% and 75% in LSIL and HSIL, respectively. Positive samples for MMP11 expression were also positive for MMP12 expression and also increased according to illness progression. In the tissues, MMP11 or MMP12 expression was observed in the cytoplasm of the neoplastic cells, while in the normal epithelium was absent. The reaction was always stronger for MMP12 than MMP11. MMP11 expression was present in 77% and 66% of LSIL and HSIL, while MMP12 expression was 73% and 68%. There was a relationship between MMP11 or MMP12 expression and HPV infection. Our data are showing a relationship between diagnostic of precursor lesions and the MMP11 and 12 expressions, suggesting that their expression could be an early event in the neoplastic lesions of the cervix and could have clinical significance.

Immunoreactivity to caspase-3, caspase-7, caspase-8, and caspase-9 forms is frequently lost in human prostate tumors

Caspases are essential initiators and executioners of apoptosis. Changes in their expression may contribute to the development of proliferative disorders such as cancer, by altering the death-proliferation homeostatic balance. The aim of this work was to analyze the expression of a broad panel of caspases at the epithelial level in human prostate tissues to assess possible prostatic disease-related alterations. We comparatively analyzed by immunohistochemistry the expression of pro-caspase-3, pro-caspase-8, pro-caspase-9, cleaved caspase-3, cleaved caspase-8, and caspase-7, in normal and pathologic (benign hyperplasic, premalignant [high-grade intraepithelial neoplasia], and cancerous [prostate cancer]) human prostate epithelium. Expression of caspases was correlated with clinicopathologic features, including preoperative prostate-specific antigen levels, Gleason scores, and biochemical progression. Percentage of positive samples for all the analyzed caspases decreased in prostate cancer versus normal prostate epithelium. The values obtained for benign prostatic hyperplasia and high-grade intraepithelial neoplasia more qualitatively resembled those of the prostate cancer group. Our results indicate that caspase expression in prostate malignant cells is reduced in a substantial number of patients and that such an alteration occurs in the premalignant stage. Loss of caspase expression could constitute a useful marker for prostate cancer diagnosis. Therapeutic approaches aimed to recover or enhance caspase expression might be effective against prostate cancer.

Epithelial membrane protein-2 promotes endometrial tumor formation through activation of FAK and Src

Endometrial cancer is the most common gynecologic malignancy diagnosed among women in developed countries. One recent biomarker strongly associated with disease progression and survival is epithelial membrane protein-2 (EMP2), a tetraspan protein known to associate with and modify surface expression of certain integrin isoforms. In this study, we show using a xenograft model system that EMP2 expression is necessary for efficient endometrial tumor formation, and we have started to characterize the mechanism by which EMP2 contributes to this malignant phenotype. In endometrial cancer cells, the focal adhesion kinase (FAK)/Src pathway appears to regulate migration as measured through wound healing assays. Manipulation of EMP2 levels in endometrial cancer cells regulates the phosphorylation of FAK and Src, and promotes their distribution into lipid raft domains. Notably, cells with low levels of EMP2 fail to migrate and poorly form tumors in vivo. These findings reveal the pivotal role of EMP2 in endometrial cancer carcinogenesis, and suggest that the association of elevated EMP2 levels with endometrial cancer prognosis may be causally linked to its effect on integrin-mediated signaling.

TACE/ADAM-17 phosphorylation by PKC-epsilon mediates premalignant changes in tobacco smoke-exposed lung cells

BACKGROUND

Tobacco smoke predisposes humans and animals to develop lung tumors, but the molecular events responsible for this are poorly understood. We recently showed that signaling mechanisms triggered by smoke in lung cells could lead to the activation of a growth factor signaling pathway, thereby promoting hyperproliferation of lung epithelial cells. Hyperproliferation is considered a premalignant change in the lung, in that increased rates of DNA synthesis are associated with an increased number of DNA copying errors, events that are exacerbated in the presence of tobacco smoke carcinogens. Despite the existence of DNA repair mechanisms, a small percentage of these errors go unrepaired and can lead to tumorigenic mutations. The results of our previous study showed that an early event following smoke exposure was the generation of oxygen radicals through the activation of NADPH oxidase. Although it was clear that these radicals transduced signals through the epidermal growth factor receptor (EGFR), and that this was mediated by TACE-dependent cleavage of amphiregulin, it remained uncertain how oxygen radicals were able to activate TACE.

PRINCIPAL FINDINGS

In the present study, we demonstrate for the first time that phosphorylation of TACE at serine/threonine residues by tobacco smoke induces amphiregulin release and EGFR activation. TACE phosphorylation is triggered in smoke-exposed lung cells by the ROS-induced activation of PKC through the action of SRC kinase. Furthermore, we identified PKCε as the PKC isoform involved in smoke-induced TACE activation and hyperproliferation of lung cells.

CONCLUSIONS

Our data elucidate new signaling paradigms by which tobacco smoke promotes TACE activation and hyperproliferation of lung cells.

MYC cooperates with AKT in prostate tumorigenesis and alters sensitivity to mTOR inhibitors

MYC and phosphoinositide 3-kinase (PI3K)-pathway deregulation are common in human prostate cancer. Through examination of 194 human prostate tumors, we observed statistically significant co-occurrence of MYC amplification and PI3K-pathway alteration, raising the possibility that these two lesions cooperate in prostate cancer progression. To investigate this, we generated bigenic mice in which both activated human AKT1 and human MYC are expressed in the prostate (MPAKT/Hi-MYC model). In contrast to mice expressing AKT1 alone (MPAKT model) or MYC alone (Hi-MYC model), the bigenic phenotype demonstrates accelerated progression of mouse prostate intraepithelial neoplasia (mPIN) to microinvasive disease with disruption of basement membrane, significant stromal remodeling and infiltration of macrophages, B- and T-lymphocytes, similar to inflammation observed in human prostate tumors. In contrast to the reversibility of mPIN lesions in young MPAKT mice after treatment with mTOR inhibitors, Hi-MYC and bigenic MPAKT/Hi-MYC mice were resistant. Additionally, older MPAKT mice showed reduced sensitivity to mTOR inhibition, suggesting that additional genetic events may dampen mTOR dependence. Since increased MYC expression is an early feature of many human prostate cancers, these data have implications for treatment of human prostate cancers with PI3K-pathway alterations using mTOR inhibitors.

Transgenic mice expressing cyclooxygenase-2 in hepatocytes reveal a minor contribution of this enzyme to chemical hepatocarcinogenesis

Cyclooxygenase-2 (COX-2) has been associated with cell growth regulation, tissue remodeling, and carcinogenesis. Ectopic expression of COX-2 in hepatocytes constitutes a nonphysiological condition ideal for evaluating the role of prostaglandins (PGs) in liver pathogenesis. The effect of COX-2-dependent PGs in chronic liver disease, hepatitis, fibrosis, and chemical hepatocarcinogenesis, has been investigated in transgenic (Tg) mice that express human COX-2 in hepatocytes and in Tg hepatic human cell lines. We have used three different complementary approaches: i) diethylnitrosamine (DEN)-induced chemical hepatocarcinogenesis in COX-2 Tg mice, ii) DEN/phenobarbital treatment of human COX-2 Tg hepatocyte-like cells, and iii) COX-2 Tg hepatocyte-like cells implants in nude mice. The data suggest that PGs produced by COX-2 in hepatocytes promoted mild hepatitis in 60-week-old mice, as assessed by histological examination, but failed to contribute to the development of liver fibrogenesis after methionine- and choline-deficient diet treatment. Moreover, liver injury, collagen content, and hepatic stellate cell activation were equally severe in wild-type and COX-2 Tg mice. The contribution of COX-2-dependent PGs to the development of DEN-induced hepatocarcinogenesis was evaluated in Tg mice, Tg hepatocyte-like cells, and nude mice and the analysis revealed that COX-2 expression favors the development of preneoplastic foci without affecting malignant transformation. Endogenous COX-2 expression in wild-type mice is a late event in the development of hepatocellular carcinoma.

Characterization of UDP-glucuronosyltransferase 2A1 (UGT2A1) variants and their potential role in tobacco carcinogenesis

OBJECTIVE

To examine UGT2A1 expression in human tissues, determine its glucuronidation activity against tobacco carcinogens, and assess the potential functional role of UGT2A1 missense single nucleotide polymorphisms on UGT2A1 enzyme activity.

METHODS

Reverse transcription polymerase chain reaction and real time polymerase chain reaction were used to assess UGT2A1 gene expression in various human tissues. A glucuronidation assay measured by reverse phase ultra-performance liquid chromatography was used to determine UGT2A1 activity.

RESULTS

UGT2A1 was expressed in aerodigestive tract tissues including trachea, larynx, tonsil, lung, and colon; no expression was observed in breast, whole brain, pancreas, prostate, kidney, liver, or esophagus. UGT2A1 exhibited highest expression in the lung, followed by trachea >tonsil >larynx >colon >olfactory tissue. Cell homogenates prepared from wildtype UGT2A1(75Lys308Gly) overexpressing HEK293 cells showed significant glucuronidation activity against a variety of polycyclic aromatic hydrocarbons including, 1-hydroxy-benzo(a)pyrene, benzo(a)pyrene-7,8-diol, and 5-methylchrysene-1,2-diol. No activity was observed in UGT2A1 overexpressing cell homogenate against substrates that form N-glucuronides, such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), nicotine, or N-OH-2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (N-OH PhIP). A significant (P<0.05) decrease (approximately 25%) in glucuronidation activity (Vmax/KM) was observed against all polycyclic aromatic hydrocarbons substrates for the UGT2A1(75Lys308Gly) variant compared with homogenates from wildtype UGT2A1(75Lys308Gly); no activity was observed for cell homogenates overexpressing the UGT2A1 variant for all substrates tested.

CONCLUSION

These data suggest that UGT2A1 is an important detoxification enzyme in the metabolism of polycyclic aromatic hydrocarbons within target tissues for tobacco carcinogens and functional polymorphisms in UGT2A1 may play a role in tobacco-related cancer risk.

Myeloid leukemia development in c-Cbl RING finger mutant mice is dependent on FLT3 signaling

Although myeloid leukemias are primarily caused by leukemic stem cells, the molecular basis of their transformation remains largely unknown. Here, by analyzing mice with a mutation in the RING finger domain of c-Cbl, we show that the E3 ubiquitin ligase activity of c-Cbl is required to restrict myeloid leukemia development. These mice develop a myeloproliferative disease which progresses to leukemia and involves hematopoietic progenitors that exhibit augmented FLT3 signaling. Suppressing this signaling through matings with FLT3 ligand knockout mice prevents leukemia development. We also observe enhanced c-Kit, Akt and Erk activity, and deregulated expression of leukemia-associated transcription factors in hematopoietic progenitors. The characterization of these perturbations provides direction for therapeutics that may aid the treatment of patients with c-Cbl mutations.

Overexpression of 5-lipoxygenase in sporadic colonic adenomas and a possible new aspect of colon carcinogenesis

PURPOSE

We aimed to study the intracellular expression of 5-lipoxygenase (5-LOX), the primary competitor with cyclooxygenase-2 in arachidonic acid metabolism, as inflammatory enzymes may be involved in blocking apoptosis and promoting cancer growth by changing arachidonic acid metabolism within cells. Our purpose was to investigate the possible connection between 5-LOX expression and colon carcinogenesis by characterizing 5-LOX expression in histologically different colonic adenomas, determining the relationship between high expression of 5-LOX and various conventional clinicopathological features of adenomas, and finally characterizing the histological localization of cells with 5-LOX overexpression.

METHODS

A total of 111 patients were examined and 120 histologically different colonic adenomas analyzed (including four cases of intramucosal adenocarcinoma in a polyp). Immunohistochemical staining with polyclonal anti-5-LOX antibodies was performed.

RESULTS

There was a significant correlation between high 5-LOX expression and patient age, increased polyp size, high grade of intraepithelial neoplasia, villous and tubulovillous adenoma, and histological epithelial localization.

CONCLUSIONS

We observed a strong positive correlation between 5-LOX overexpression and the appearance of typical high-risk factors for malignant transformation in adenomatous polyps. The results support the role of 5-LOX in early stages of colon carcinogenesis.

The PI3K-Akt-mTOR pathway in initiation and progression of thyroid tumors

The phosphoinositide-3 (OH) kinase (PI3K) signaling cascade is involved in regulating glucose uptake and metabolism, growth, motility, and other essential functions for cell survival. Unregulated activation of this pathway commonly occurs in cancer through a variety of mechanisms, including genetic mutations of kinases and regulatory proteins, epigenetic alterations that alter gene expression and translation, and posttranslational modifications. In thyroid cancer, constitutive activation of PI3K signaling has been shown to play a role in the genetic predisposition for thyroid neoplasia in Cowden's syndrome, and is recognized to be frequently overactivated in sporadic forms of thyroid cancer including those with aggressive clinical behaviors. In this review, the key signaling molecules in the PI3K signaling cascade, the abnormalities known to occur in thyroid cancer, and the potential for therapeutic targeting of PI3K pathway members will be discussed.

Jnk2 effects on tumor development, genetic instability and replicative stress in an oncogene-driven mouse mammary tumor model

Oncogenes induce cell proliferation leading to replicative stress, DNA damage and genomic instability. A wide variety of cellular stresses activate c-Jun N-terminal kinase (JNK) proteins, but few studies have directly addressed the roles of JNK isoforms in tumor development. Herein, we show that jnk2 knockout mice expressing the Polyoma Middle T Antigen transgene developed mammary tumors earlier and experienced higher tumor multiplicity compared to jnk2 wildtype mice. Lack of jnk2 expression was associated with higher tumor aneuploidy and reduced DNA damage response, as marked by fewer pH2AX and 53BP1 nuclear foci. Comparative genomic hybridization further confirmed increased genomic instability in PyV MT/jnk2−/− tumors. In vitro, PyV MT/jnk2−/− cells underwent replicative stress and cell death as evidenced by lower BrdU incorporation, and sustained chromatin licensing and DNA replication factor 1 (CDT1) and p21^Waf1 protein expression, and phosphorylation of Chk1 after serum stimulation, but this response was not associated with phosphorylation of p53 Ser15. Adenoviral overexpression of CDT1 led to similar differences between jnk2 wildtype and knockout cells. In normal mammary cells undergoing UV induced single stranded DNA breaks, JNK2 localized to RPA (Replication Protein A) coated strands indicating that JNK2 responds early to single stranded DNA damage and is critical for subsequent recruitment of DNA repair proteins. Together, these data support that JNK2 prevents replicative stress by coordinating cell cycle progression and DNA damage repair mechanisms.

Overexpression of the JmjC histone demethylase KDM5B in human carcinogenesis: involvement in the proliferation of cancer cells through the E2F/RB pathway

BACKGROUND

Although an increasing number of histone demethylases have been identified and biochemically characterized, their biological functions largely remain uncharacterized, particularly in the context of human diseases such as cancer. We investigated the role of KDM5B, a JmjC histone demethylase, in human carcinogenesis. Quantitative RT-PCR and microarray analyses were used to examine the expression profiles of histone demethylases in clinical tissue samples. We also examined the functional effects of KDM5B on the growth of cancer cell lines treated with small interfering RNAs (siRNAs). Downstream genes and signal cascades induced by KDM5B expression were identified from Affymetrix Gene Chip experiments, and validated by real-time PCR and reporter assays. Cell cycle-dependent characteristics of KDM5B were identified by immunofluorescence and FACS.

RESULTS

Quantitative RT-PCR analysis confirmed that expression levels of KDM5B are significantly higher in human bladder cancer tissues than in their corresponding non-neoplastic bladder tissues (P < 0.0001). The expression profile analysis of clinical tissues also revealed up-regulation of KDM5B in various kinds of malignancies. Transfection of KDM5B-specific siRNA into various bladder and lung cancer cell lines significantly suppressed the proliferation of cancer cells and increased the number of cells in sub-G1 phase. Microarray expression analysis indicated that E2F1 and E2F2 are downstream genes in the KDM5B pathway.

CONCLUSIONS

Inhibition of KDM5B may affect apoptosis and reduce growth of cancer cells. Further studies will explore the pan-cancer therapeutic potential of KDM5B inhibition.

[Expression of survivin, caspase-3 in oral precancerous lesions and oral squamous-cell carcinoma]

OBJECTIVE

To investigate the roles of surviving and caspase-3 in the development of oral cancer.

METHODS

Archival tissue sections of 17 oral squamous cell carcinoma (OSCC), 28 oral leukoplakia with dysplasia, 10 normal oral mucosa were obtained from Capital Medical University School of Stomatology for immunohistochemical staining of markers of survivin and caspase-3. The cell apoptosis was detected with terminal deoxynucleotidyl transferase-mediated nucleotide shift enzyme (TdT) mediated d-UTP end labeling (TUNEL). Positively stained cells were counted and analyzed statistically to determine potential relationship between survivin, caspase-3 and cell apoptosis.

RESULTS

The expression of survivin was faint or negative in normal epithelial cells. The average positive rate of survivin was (1.05 ± 1.21)% in control group and (21.89 ± 10.45)% in OSCC. Caspase-3 was expressed in all the normal mucosa,but it obviously down-regulated in dysplasia and OSCC. The apoptosis index (AI) decreased from (0.89 ± 0.46)% in normal mucosa to (0.21 ± 0.12)% in OSCC.

CONCLUSIONS

Both survivin and caspase-3 are associated with carcinogenesis of the oral mucosa. Survivin may restrain cell apoptosis by inhibiting caspase-3.

Matrix metalloproteinase-7 and premalignant host responses in Helicobacter pylori-infected mice

Helicobacter pylori-induced gastritis is the strongest singular risk factor for gastric adenocarcinoma. Matrix metalloproteinase-7 (MMP-7) is a proteolytic enzyme that can modify the intestinal microbial replicative niche as well as affect tumorigenesis, and H. pylori stimulates expression of MMP-7 in gastric epithelial cells in vitro. Utilizing a transgenic murine model of H. pylori-mediated injury, our experiments now show that gastric inflammation is increased within the context of MMP-7 deficiency, which involves both Th1- and Th17-mediated pathways. Enhanced gastritis in H. pylori-infected mmp-7-/- mice is strongly linked to accelerated epithelial cellular turnover. However, more severe inflammation and heightened proliferation and apoptosis are not dependent on MMP-7-mediated bacterial eradication. Collectively, these studies indicate that H. pylori-mediated induction of MMP-7 may serve to protect the gastric mucosa from pathophysiologic processes that promote carcinogenesis.

Tgfbr1 haploinsufficiency inhibits the development of murine mutant Kras-induced pancreatic precancer

To dissect the role of constitutively altered Tgfbr1 signaling in pancreatic cancer development, we crossed Elastase-Kras(G12D) (EL-Kras) mice with Tgfbr1 haploinsufficient mice to generate EL-Kras/Tgfbr1(+/-) mice. Mice were euthanized at 6 to 9 months to compare the incidence, frequency, and size of precancerous lesions in the pancreas. Only 50% of all EL-Kras/Tgfbr1(+/-) mice developed preinvasive lesions compared with 100% of EL-Kras (wild-type Tgfbr1) mice. The frequency of precancerous lesions was 4-fold lower in haploinsufficient than in control mice. Paradoxically, the precancerous lesions of EL-Kras/Tgfbr1(+/-) mice were considerably larger than those in EL-Kras mice. Yet, the mitotic index of precancerous cells and the observable levels of fibrosis, lipoatrophy, and lymphocytic infiltration were reduced in EL-Kras/Tgfbr1(+/-) mice. We conclude that Tgfbr1 signaling promotes the development of precancerous lesions in mice. These findings suggest that individuals with constitutively decreased TGFBR1 expression may have a decreased risk of pancreatic cancer.

Expression of interleukin-1 receptor-associated kinase-1 in non-small cell lung carcinoma and preneoplastic lesions

PURPOSE

To identify the pattern of interleukin-1 receptor-associated kinase (IRAK-1) protein expression in non-small cell lung carcinoma (NSCLC) and corresponding preneoplastic lesions.

EXPERIMENTAL DESIGN

Archived tissue from NSCLC (adenocarcinoma and squamous cell carcinoma; n = 306) and adjacent bronchial epithelial specimens (n = 315) were analyzed for the immunohistochemical expression of IRAK-1, and the findings were correlated with patients' clinicopathologic features. Furthermore, we investigated the correlation between IRAK-1 expression and expression of NF-kappaB and IL-1alpha in tumor specimens.

RESULTS

NSCLC tumors showed significantly higher cytoplasmic and lower nuclear IRAK-1 expression than normal epithelium. Squamous dysplasias had significantly higher cytoplasmic IRAK-1 expression than normal epithelium. In tumors, a significant positive correlation was detected between IRAK-1 expression (nuclear and cytoplasmic; P = 0.011) and IL-1alpha cytoplasmic expression (P < 0.0001). The correlation between the expression of the markers and patients' clinicopathologic features varied according to tumor histologic type and sex. High IRAK-1 cytoplasmic expression correlated with worse recurrence-free survival in women with NSCLC [hazard ratio (HR), 2.204; P = 0.033], but not in men. In adenocarcinoma, combined low level of expression of nuclear IRAK-1 and NF-kappaB correlated significantly with worse overall (HR, 2.485; P = 0.007) and recurrence-free (HR, 3.058; P = 0.006) survivals in stage I/II patients.

CONCLUSIONS

IRAK-1 is frequently expressed in NSCLC tissue specimens, and this expression is an early phenomenon in the sequential development of lung cancer. IRAK-1 is a novel inflammation-related marker and a potential target for lung cancer chemopreventive strategies.

High expression of PGE2 enzymatic pathways in cervical (pre)neoplastic lesions and functional consequences for antigen-presenting cells

Although human papillomavirus (HPV) DNA is detected in the majority of squamous intraepithelial lesions (SIL) and carcinoma (SCC) of the uterine cervix, the persistence or progression of cervical lesions suggest that viral antigens are not adequately presented to the immune system. This hypothesis is reinforced by the observation that most SIL show quantitative and functional alterations of Langerhans cells (LC). The aim of this study was to determine whether prostaglandins (PG) may affect LC density in the cervical (pre)neoplastic epithelium. We first demonstrated that the epithelial expression of PGE(2) enzymatic pathways, including cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase 1 (mPGES-1), is higher in SIL and SCC compared to the normal exocervical epithelium and inversely correlated to the density of CD1a-positive LC. By using cell migration assays, we next showed that the motility of immature dendritic cells (DC) and DC partially differentiated in vitro in the presence of PGE(2) are differentially affected by PGE(2). Immature DC had a lower ability to migrate in the presence of PGE(2) compared to DC generated in vitro in the presence of PGE(2). Finally, we showed that PGE(2) induced a cytokine production profile and phenotypical features of tolerogenic DC, suggesting that the altered expression of PGE(2) enzymatic pathways may promote the cervical carcinogenesis by favouring (pre)cancer immunotolerance.

The chemopreventive agent myoinositol inhibits Akt and extracellular signal-regulated kinase in bronchial lesions from heavy smokers

Myoinositol is an isomer of glucose that has chemopreventive activity in animal models of cancer. In a recent phase I clinical trial, myoinositol administration correlated with a statistically significant regression of preexisting bronchial dysplastic lesions in heavy smokers. To shed light on the potential mechanisms involved, activation of Akt and extracellular signal-regulated kinase (ERK), two kinases that control cellular proliferation and survival, was assessed in 206 paired bronchial biopsies from 21 patients who participated in this clinical trial. Before myoinositol treatment, strongly positive staining for activation of Akt was detected in 27% of hyperplastic/metaplastic lesions and 58% of dysplastic lesions (P = 0.05, chi(2) test). There was also a trend toward increased activation of ERK (28% in regions of hyperplasia/metaplasia to 42% of dysplastic lesions). Following myoinositol treatment, significant decreases in Akt and ERK phosphorylation were observed in dysplastic (P < 0.01 and 0.05, respectively) but not hyperplastic/metaplastic lesions (P > 0.05). In vitro, myoinositol decreased endogenous and tobacco carcinogen-induced activation of Akt and ERK in immortalized human bronchial epithelial cells, which decreased cell proliferation and induced a G(1)-S cell cycle arrest. These results show that the phenotypic progression of premalignant bronchial lesions from smokers correlates with increased activation of Akt and ERK and that these kinases are targets of myoinositol. Moreover, they suggest that myoinositol might cause regression of bronchial dysplastic lesions through inhibition of active Akt and ERK.

The pace of prostatic intraepithelial neoplasia development is determined by the timing of Pten tumor suppressor gene excision

Loss of the PTEN tumor suppressor is a common occurrence in human prostate cancer, particularly in advanced disease. In keeping with its role as a pivotal upstream regulator of the phosphatidylinositol 3-kinase signaling pathway, experimentally-induced deletion of Pten in the murine prostate invariably results in neoplasia. However, and unlike humans where prostate tumorigenesis likely evolves over decades, disease progression in the constitutively Pten deficient mouse prostate is relatively rapid, culminating in invasive cancer within several weeks post-puberty. Given that the prostate undergoes rapid androgen-dependent growth at puberty, and that Pten excisions during this time might be especially tumorigenic, we hypothesized that delaying prostate-specific Pten deletions until immediately after puberty might alter the pace of tumorigenesis. To this end we generated mice with a tamoxifen-inducible Cre recombinase transgene enabling temporal control over prostate-specific gene alterations. This line was then interbred with mice carrying floxed Pten alleles. Despite evidence of increased Akt/mTOR/S6K axis activity at early time points in Pten-deficient epithelial cells, excisions induced in the post-pubertal (6 wk-old) prostate yielded gradual acquisition of a range of lesions. These progressed from pre-malignant changes (nuclear atypia, focal hyperplasia) and low grade prostatic intraepithelial neoplasia (PIN) at 16-20 wks post-tamoxifen exposure, to overtly malignant lesions by approximately 1 yr of age, characterized by high-grade PIN and microinvasive carcinoma. In contrast, when Pten excisions were triggered in the pre-pubertal (2 week-old) prostate, neoplasia evolved over a more abbreviated time-frame, with a spectrum of premalignant lesions, as well as overt PIN and microinvasive carcinoma by 10-12 wks post-tamoxifen exposure. These results indicate that the developmental stage at which Pten deletions are induced dictates the pace of PIN development.

[Changes of alternative splicing variants of human telomerase reverse transcriptase during gastric carcinogenesis]

BACKGROUND & OBJECTIVE

The expression of human telomerase reverse transcriptase (hTERT) is positively correlated to the activity of telomerase. Alternative splicing exists in the transcription of hTERT and special splicing patterns may change during tumor progression. This study was to reveal the changes of hTERT alterative splicing pattern in gastric carcinogenesis.

METHODS

Three alternative splicing sites (alpha, beta, gamma) were selected to design primers. The expression of eight hTERT alternative splicing variants (ASVs) in 18 specimens of normal gastric mucosa, 20 specimens of precancerous lesions and 19 specimens of gastric cancer was detected by semi-nested reverse transcription-polymerase chain reaction (RT-PCR). The expression of beta site-remaining ASV (beta+ hTERT mRNA) in precancerous lesions and gastric cancer tissues was detected by SYBR Green real-time RT-PCR.

RESULTS

The positive rate of alpha+beta+gamma+ hTERT mRNA was significantly higher in gastric cancer than in precancerous lesions and normal mucosa (94.7% vs. 40.0% and 0, P<0.05). The positive rates of other ASVs were not different among the three groups. The positive rates of beta-deletion ASV were 72.2% in normal mucosa, 95.0% in precancerous lesions and 100.0% in gastric cancer. The positive rates of beta+ hTERT mRNA (including alpha+beta+gamma+ hTERT mRNA, alpha-deletion ASV, gamma-deletion ASV, alphagamma-deletion ASV) were 11.1% in normal mucosa, 40.0% in precancerous lesions and 94.7% in gastric cancer (P<0.05). The mRNA level of beta+ hTERT was 6.99 times higher in gastric cancer than in precancerous lesions.

CONCLUSIONS

hTERT alternative splicing pattern changes during gastric carcinogenesis. beta+ hTERT mRNA is expressed increasingly during gastric carcinogenesis and may provide useful information for diagnosis of gastric cancer or precancerous lesions.

[Immunohistochemical analysis of nuclear factor, p38, and cyclin D1 proteins in premalignant lesions and carcinomas of the colorectal mucosa]

BACKGROUND/AIMS

Nuclear factor-kappaB p65 (NF-kappaB p65), nuclear factor-kappaB1 p50 (NF-kappaB p50) have been shown to play a role in cell proliferation, apoptosis, cytokine production, and oncogenesis. Recently, p38 mitogen-activated protein kinase (MAPK)/ NF-kappaB/ cyclin D1 signaling pathway has been shown to play an important part in the pathogenesis of human cancers. This study was designed to investigate the expression of NF-kappaB p65, NF-kappaB p50, p38 MAPKalpha, and cyclin D1 proteins in premalignant lesions of colon and colorectal adenocarcinoma.

METHODS

Paraffin sections of 20 normal mucosa, 20 low-grade tubular adenoma, 20 high-grade tubular adenoma and 64 adenocarcinoma tissues were analysed immunohistochemically for the expression of NF-kappaB p65, NF-kappaB p50, p38 MAPKalpha, and cyclin D1 proteins.

RESULTS

The expression of NF-kappaB p65, NF-kappaB p50, and p38 MAPKalpha proteins were significantly higher in adenocarcinoma tissue in comparison with that in normal mucosa, low-grade tubular adenoma, and high-grade tubular adenoma tissues. Expression of NF-kappaB p50 was more frequent in poorly differentiated histologic grade, presence of nodal metastasis, and advanced stage. Expression of p38 MAPKalpha protein was higher in advanced tumor stage, presence of nodal metastasis and advanced stage. Synchronous expression of NF-kappaB p65, NF-kappaB p50, p38 MAPKalpha, and cyclin D1 proteins were significantly higher in adenocarcinoma tissue.

CONCLUSIONS

With the increased expression of NF-kappaB p65, NF-kappaB p50, and p38 MAPKalpha proteins, p38 MAPK/ NF-kappaB/ cyclin D1 signaling pathway may play a role in the pathogenesis of colorectal carcinoma.

Chk2 suppresses the oncogenic potential of DNA replication-associated DNA damage

The Mre11 complex (Mre11, Rad50, and Nbs1) and Chk2 have been implicated in the DNA-damage response, an inducible process required for the suppression of malignancy. The Mre11 complex is predominantly required for repair and checkpoint activation in S phase, whereas Chk2 governs apoptosis. We examined the relationship between the Mre11 complex and Chk2 in the DNA-damage response via the establishment of Nbs1(DeltaB/DeltaB) Chk2(-/-) and Mre11(ATLD1/ATLD1) Chk2(-/-) mice. Chk2 deficiency did not modify the checkpoint defects or chromosomal instability of Mre11 complex mutants; however, the double-mutant mice exhibited synergistic defects in DNA-damage-induced p53 regulation and apoptosis. Nbs1(DeltaB/DeltaB) Chk2(-/-) and Mre11(ATLD1/ATLD1) Chk2(-/-) mice were also predisposed to tumors. In contrast, DNA-PKcs-deficient mice, in which G1-specific chromosome breaks are present, did not exhibit synergy with Chk2(-/-) mutants. These data suggest that Chk2 suppresses the oncogenic potential of DNA damage arising during S and G2 phases of the cell cycle.

Evidence for editing of human papillomavirus DNA by APOBEC3 in benign and precancerous lesions

Cytidine deaminases of the APOBEC3 family all have specificity for single-stranded DNA, which may become exposed during replication or transcription of double-stranded DNA. Three human APOBEC3A (hA3A), hA3B, and hA3H genes are expressed in keratinocytes and skin, leading us to determine whether genetic editing of human papillomavirus (HPV) DNA occurred. In a study of HPV1a plantar warts and HPV16 precancerous cervical biopsies, hyperedited HPV1a and HPV16 genomes were found. Strictly analogous results were obtained from transfection experiments with HPV plasmid DNA and the three nuclear localized enzymes: hA3A, hA3C, and hA3H. Thus, stochastic or transient overexpression of APOBEC3 genes may expose the genome to a broad spectrum of mutations that could influence the development of tumors.

Renal carcinogenesis in models of diabetes in rats: metabolic changes are closely related to neoplastic development

AIMS/HYPOTHESIS

There is an increased risk of renal cell carcinoma (RCC) in human diabetes mellitus. We therefore examined the influence of hyperglycaemia and glucose-lowering treatment on nephrocarcinogenesis in rats.

METHODS

Rats (n = 850), which were either spontaneously diabetic, streptozotocin-diabetic or normoglycaemic, were examined with special reference to Armanni-Ebstein lesions (AEL).

RESULTS

Irrespective of the cause of diabetes, diabetic but not normoglycaemic rats developed typical glycogenotic clear-cell AEL. AEL showed strong proliferative activity, which was nearly completely inhibited by EGF receptor blockade (Gefitinib treatment). Many findings suggested a stepwise development of RCCs from AEL. Whereas the number and size of RCCs gradually increased in all diabetic groups, beginning at 6 months after onset of diabetes, normoglycaemic controls did not developed RCC. After 28 months, up to 82% of diabetic animals had at least one RCC. In contrast to the proximal tubules, the distal tubular system, including glycogenotic AEL, had the same levels of enzyme activities as RCC (e.g. high glycogen phosphorylase and synthase activity, lack of glucose 6-phosphatase activity) and the same expression patterns of cytokeratin 7 and several growth factors, along with their receptors and signal transduction proteins (TGF-alpha, EGF receptor, IGF-I, IGF-I receptor, IGF-II receptor, insulin receptor substrate 1, v-raf-1 murine leukemia viral oncogene homologue 1 and mitogen activated protein kinase kinase 1). In addition, direct morphological transitions between distal tubules, AEL and RCCs were frequently observed. All these findings indicate a common origin and a precursor-product relationship of AEL and RCCs.

CONCLUSIONS/INTERPRETATION

Nephrocarcinogenesis in diabetic rats results from sustained hyperglycaemia, resulting in an adaptive metabolic response, altered growth factor signalling and subsequent neoplastic transformation of the tubular epithelial cells.

-lipoic acid promotes the growth of rat hepatic pre-neoplastic lesions in the choline-deficient model

alpha-lipoic acid (alpha-LA) is an antioxidant used in a number of conditions related to liver diseases. Herein, we investigated the effect of alpha-LA on the development of rat pre-neoplastic lesions generated by a model of hepatocarcinogenesis, which has similarities in its histopathological sequence to human hepatocellular carcinoma development with cirrhosis. Initiation of hepatocytes was achieved by treatment with a single dose of diethylnitrosamine and promotion by feeding a choline-methionine-deficient diet (CMD), with or without alpha-LA. Pre-neoplastic lesions were identified by their positivity to the placental form of glutathione S-transferase (GSTP) or to gamma glutamyl transpeptidase. alpha-LA given to rats fed a CMD for 6 weeks dramatically increased the number of GSTP-positive foci as compared with rats fed a CMD alone (96/cm(2) versus 7/cm(2)), the mean foci area (0.033 versus 0.008 mm(2)) and the percentage of GSTP-positive liver tissue (3.01 versus 0.07%). Essentially similar results were obtained after 10 weeks of treatment. Co-treatment with CMD + alpha-LA also resulted in the enhancement of fat accumulation, lipid peroxidation and hepatocyte death; increased expression of tumor necrosis factor-alpha, cytochrome 2E1 and cyclooxygenase-2, enhanced activation of c-jun N-terminal kinase and signal transducer activator of transcription 3, and chronic hepatocyte proliferation was also observed. No such effects were observed when alpha-LA was added to a choline-supplemented diet. In conclusion, administration of alpha-LA in conditions associated with hepatic damage aggravates liver injury and stimulates the development of pre-neoplastic lesions; the results also suggest caution in its use in the presence of chronic liver injury.

Inhibition of lipid peroxidation and enhancement of GST activity by cardamom and cinnamon during chemically induced colon carcinogenesis in Swiss albino mice

Globally, colorectal cancer is the third commonest cancer in men since 1975.The present study focuses on the preventive strategies aimed at reducing the incidences and mortality of large bowel cancer. Chemoprevention of colon cancer appears to be a very realistic possibility because various intermediate stages have been identified preceding the development of malignant colonic tumors. Several studies have demonstrated that generous consumption of vegetables reduces the risk of colon cancer. This idea has prompted the present investigation to search for some novel plant products, which may have possible anticarcinogenic activity. It has already been proved from various experiments that chemopreventive agents, by virtue of their anti-oxidant, anti-inflammatory, anti-proliferative, apoptosis-inducing activity, act at various levels including molecular, cellular, tissue and organ levels to interfere with carcinogens. Previous studies from our laboratory have already reported the inhibitory effect of cinnamon and cardamom on azoxymethane induced colon carcinogenesis by virtue of their anti-inflammatory, anti-proliferative and pro-apoptotic activity. This particular experiment was carried out to assess the anti-oxidative potential of these spices. Aqueous suspensions of cinnamon and cardamom have been shown to enhance the level of detoxifying enzyme (GST activity) with simultaneous decrease in lipid peroxidation levels in the treatment groups when compared to that of the carcinogen control group.

Requirement of MMP-3 in anchorage-independent growth of oral squamous cell carcinomas

BACKGROUND

Matrix metalloproteinase-3 (MMP-3) is expressed in various carcinomas; however, its function is not clearly established. This study was to assess its possible role in oral squamous cell carcinomas (OSCCs).

MATERIALS AND METHODS

Specimens of seven oral pre-malignant lesions (OPMLs) and 92 OSCCs were subjected to MMP-3 detection by RT-PCR and Western blot. Antisense oligodeoxynucleotides (AODNs) of MMP-3 were used to transfect OSCC (OECM-1 and SCC-9) and esophageal carcinoma (CE81T/VGH) cell lines, and their growth was subsequently analyzed by XTT and soft-agar colony assay.

RESULTS

MMP-3 transcript was preferentially expressed in OSCCs (71 of 92, 77%) than in OPMLs (two of seven, 29%; P = 0.012). Both MMP-3 transcript and protein levels were significantly higher in OSCC masses than in neighboring tissues (P < 0.0001 and P = 0.04, respectively). Growth of the three cell lines was not affected, while the colony numbers of OECM-1 and CE81T/VGH were significantly reduced by the transfection of MMP-3 AODNs (P = 0.002 and P = 0.004, respectively). SCC-9 did not form colonies in soft-agar/medium.

CONCLUSIONS

MMP-3 function may be required in most OSCCs, and it may support the anchorage-independent growth of both OSCC and esophageal carcinoma.

Changes in the antioxidant defense and hepatic drug metabolizing enzyme and isoenzyme levels, 8-hydroxydeoxyguanosine formation and expressions of c-raf.1 and insulin-like growth factor II genes during the stages of development of hepatocellular carcinoma in rats

This is an extensive study in a defined initiation-promotion hepatocellular carcinoma model of hepatocarcinogenesis (in rats) in which many important marker enzymes and isoenzymes and 8-hydroxydeoxyguanosine formation have been studied together with two very important cellular proliferating genes, insulin-like growth factor II and c-raf.1, known for their role in hepatocellular cancer development. Experiments were carried out on hepatic tissues of male Sprague-Dawley rats. Variations in different enzyme/isoenzyme activities/contents/expression pattern and 8-hydroxydeoxyguanosine-positive cells were studied. Insulin-like growth factor II and c-raf.1 gene expressions were monitored. A direct shift with increase in size and numbers of lesions was found to occur in different experimental groups. In this study, glutathione peroxidase (1.14 and 1.46-fold) and reduced triphosphopyridine nucleotide (TPNH)-cytochrome-c-reductase (1.94 and 2.94-fold) activities, cytochrome b5 (1.57 and 3.28-fold) and P-450 contents (1.45 and 1.22-fold), glutathione content (1.27 and 1.45-fold) and superoxide dismutase and catalase (1.16 and 1.39-fold) activities in group A animals were found to be lower than those in initiation and promotion studies, respectively. 8-Hydroxydeoxyguanosine-positive nuclei count showed that oxidative damage of nuclear DNA enhanced with the progress of the disease. The insulin-like growth factor II expression was found to be predominant in hepatocellular carcinoma and in early preneoplastic lesions. Unlike insulin-like growth factor II, c-raf.1 expression was located in the late basophilic lesions associated with hepatocellular carcinoma. During the various stages of the development of hepatocellular carcinoma, the enzymes played a significant role in metabolizing carcinogens and thereby scavenging various toxic metabolites or free radicals produced. A sequence of cellular changes starting from the appearance of glycogen storage foci to basophilic foci leading to hepatocellular carcinoma via mixed cell foci varied the activity/content or expression pattern of the enzymes and isoenzymes and in 8-hydroxydeoxyguanosine formation. It has been established that c-raf.1-induced signaling pathways activated by insulin-like growth factor II is implicated in the late stage of development of cancer.

[Cyclooxygenase 2 and colorectal cancer: therapeutic implications]

There is epidemiological evidence that suggests an inverse association between the consumption of non-steroidal anti-inflammatories (NSAIDs) and the risk of developing certain neoplasms. This association led to the identification of the therapeutic target of these drugs, cyclooxygenase type 2 (COX-2). Later studies have demonstrated that COX-2 is over-expressed in many malignant and pre-malignant lesions of different origins, among which are included colorectal neoplasms. This factor explains the beneficial effect observed with the use of classic NSAIDs and more recently, with selective COX-2 inhibitors (coxibs), in the treatment and/or prevention of several neoplasms.

α-Methylacyl-CoA-Racemase Expression in Adenocarcinoma, Dysplasia and Non-Neoplastic Epithelium of the Stomach

Alpha-methylacyl-CoA-racemase (AMACR) is an essential enzyme in the oxidation of bile acid intermediates and branched-chain fatty acids. This study aims to examine the expression pattern, as well as diagnostic and prognostic significance, of AMACR in carcinoma, dysplasia and non-neoplastic epithelium of the stomach. A total of 158 cases, including 66 cases of gastric carcinoma (GC), 48 cases of dysplasia and 44 cases of non-neoplastic gastric mucosa, were examined by immunohistochemistry for AMACR. AMACR expression was divided into two categories: negative (negative-weak staining intensity) and positive (moderate-strong staining intensity). AMACR immunoreactivity was detected in only 2 of 44 (4.5%) cases of non-neoplastic epithelium. A significantly high frequency of AMACR expression was found in 40 of 48 (83.3%) cases of dysplasia and 34 of 66 (51.5%) carcinoma cases compared with cases of non-neoplastic epithelium (p < 0.05). The frequency of AMACR expression was significantly higher in dysplasia than in carcinoma cases (p < 0.05). AMACR expression was higher in intestinal- than diffuse-type GC (p < 0.05). In conclusion, this study suggests that AMACR immunostaining aids in distinguishing malignant or precancerous lesions from reactive epithelial atypia in gastric biopsy specimens. It also suggests that AMACR expression is more likely to be associated with intestinal-type adenocarcinoma in gastric carcinogenesis.

Activation of the serine/threonine protein kinase Akt during the progression of Barrett neoplasia

Esophageal adenocarcinoma has demonstrated a rapid increase in incidence over the last 10 years. This increase mirrors a dramatic rise in that of Barrett esophagus, which is associated with esophageal adenocarcinoma in at least 95% of cases. In an attempt to understand the pathogenesis of esophageal adenocarcinoma, attention has turned to the antiapoptotic and oncogenic pathways. Here we demonstrated that Akt was frequently activated in Barrett esophagus-related adenocarcinoma. Remarkably, the levels of Akt activation were associated with tumor progression. After institutional review board ethics approval, 60 archival tissue specimens of esophageal adenocarcinoma arising on a background of Barrett esophagus were selected for immunohistochemical staining with phosphorylated Akt (p-Akt) antibody. The slides were scored by 2 independent observers. Approximately 80% of high-grade dysplasia and esophageal adenocarcinoma cases demonstrated strong to moderate Akt activity. Sixty-two percent of Barrett mucosa revealed low Akt activity, the remaining cases being p-Akt negative. None of the low-grade dysplasia cases exhibited strong p-Akt staining, whereas only weak p-Akt activity is seen in a portion of metaplastic Barrett mucosa, Akt is highly activated in high-grade dysplasia and esophageal adenocarcinoma arising from Barrett esophagus. These findings suggest a role of p-Akt in the progression of Barrett esophagus to esophageal adenocarcinoma and provide the rationale for using p-Akt inhibitor API-2/triciribine, which is currently in clinical trial, in the treatment of esophageal adenocarcinoma.

Expression of LIM kinase 1 is associated with reversible G1/S phase arrest, chromosomal instability and prostate cancer

Background

LIM kinase 1 (LIMK1), a LIM domain containing serine/threonine kinase, modulates actin dynamics through inactivation of the actin depolymerizing protein cofilin. Recent studies have indicated an important role of LIMK1 in growth and invasion of prostate and breast cancer cells; however, the molecular mechanism whereby LIMK1 induces tumor progression is unknown. In this study, we investigated the effects of ectopic expression of LIMK1 on cellular morphology, cell cycle progression and expression profile of LIMK1 in prostate tumors.

Results

Ectopic expression of LIMK1 in benign prostatic hyperplasia cells (BPH), which naturally express low levels of LIMK1, resulted in appearance of abnormal mitotic spindles, multiple centrosomes and smaller chromosomal masses. Furthermore, a transient G1/S phase arrest and delayed G2/M progression was observed in BPH cells expressing LIMK1. When treated with chemotherapeutic agent Taxol, no metaphase arrest was noted in these cells. We have also noted increased nuclear staining of LIMK1 in tumors with higher Gleason Scores and incidence of metastasis.

Conclusion

Our results show that increased expression of LIMK1 results in chromosomal abnormalities, aberrant cell cycle progression and alteration of normal cellular response to microtubule stabilizing agent Taxol; and that LIMK1 expression may be associated with cancerous phenotype of the prostate.

Activation of Akt is increased in the dysplasia-carcinoma sequence in Barrett's oesophagus and contributes to increased proliferation and inhibition of apoptosis: a histopathological and functional study

Background

The incidence of oesophageal adenocarcinoma is increasing rapidly in the developed world. The serine-threonine protein kinase and proto-oncogene Akt has been reported to regulate proliferation and apoptosis in several tissues but there are no data on the involvement of Akt in oesophageal carcinogenesis. Therefore we have examined the activation of Akt in Barrett's oesophagus and oesophageal adenocarcinoma and the functional effects of Akt activation in vitro.

Methods

Expression of total and active (phosphorylated) Akt were determined in endoscopic biopsies and surgical resection specimens using immunohistochemistry. The functional effects of Akt were examined using Barrett's adenocarcinoma cells in culture.

Results

In normal squamous oesophagus, erosive oesophagitis and non-dysplastic Barrett's oesophagus, phospho-Akt was limited to the basal 1/3 of the mucosa. Image analysis confirmed that Akt activation was significantly increased in non-dysplastic Barrett's oesophagus compared to squamous epithelium and further significantly increased in high-grade dysplasia and adenocarcinoma. In all cases of high grade dysplasia and adenocarcinoma Akt was activated in the luminal 1/3 of the epithelium. Transient acid exposure and the obesity hormone leptin activated Akt, stimulated proliferation and inhibited apoptosis: the combination of acid and leptin was synergistic. Inhibition of Akt phosphorylation with LY294002 increased apoptosis and blocked the effects of acid and leptin both alone and in combination. Activation of Akt was associated with downstream phosphorylation and deactivation of the pro-apoptotic protein Bad and phosphorylation of the Forkhead family transcription factor FOXO1.

Conclusion

Akt is abnormally activated in Barrett's oesophagus, high grade dysplasia and adenocarcinoma. Akt activation promotes proliferation and inhibits apoptosis in Barrett's adenocarcinoma cells and both transient acid exposure and leptin stimulate Akt phosphorylation. Downstream targets of Akt include Bad and Forkhead transcription factors. Activation of Akt in obesity and by reflux of gastric acid may be important in the pathogenesis of Barrett's adenocarcinoma

The role of angiogenesis and COX-2 expression in the evolution of vulvar lichen sclerosus to squamous cell carcinoma of the vulva

OBJECTIVES

We aimed to determine whether premalignant changes in vulvar lichen sclerosus (LS) could be identified by analysing markers of angiogenesis and the expression of the enzyme cyclooxygenase-2 (COX-2).

METHODS

Eight cases of histologically diagnosed vulvar LS, which showed an evolution to carcinoma of the vulva histologically documented, were compared to 10 cases of vulvar LS, for which follow-up information was available for at least 9 years, and to 10 cases of LS adjacent to squamous cell carcinoma (SCC) of the vulva. The microvessel density (MVD), and the expression of vascular endothelial growth factor (VEGF) and of COX-2 were analysed.

RESULTS

Difference of MVD between unchanged LS cases and LS cases evolving to SCC and LS adjacent to SCC cases was statistically significant (P=0.008, Wilcoxon Mann-Whitney test). Difference of VEGF and COX-2 expression between unchanged LS cases and LS cases evolving to SCC and LS adjacent to SCC cases were statistically significant (P=0.007 and P=0.01, respectively; Fisher's exact test).

CONCLUSIONS

Our study addresses the possibility that immunohistochemical studies may add information to permit the identification of LS as a precursor lesion that has a greater potential to evolve into SCC. These data may identify characteristics of vulvar LS disclosing alterations that indicate the further development to cancer; therefore, it may allow the identification of a group of LS patients who need a careful follow-up and adjunctive biopsies.

Promoter hypomethylation of protease-activated receptor 2 associated with carcinogenesis in the stomach

BACKGROUND AND AIM

Trypsin acting at protease-activated receptor 2 (PAR2) contributes to a progression of malignant tumors. An abnormal DNA methylation has been recognized as an important molecular mechanism for the genesis of various types of cancers. We attempted to clarify the relationship between the promoter methylation of PAR2 and gastric cancer.

METHOD

We estimated the methylation of the PAR2 promoter in both antral non-cancerous mucosa and cancer lesions in 94 patients with gastric cancer. We employed a methylation-specific PCR method.

RESULTS

Regarding the methylation ratio (MR) of antral-non-cancerous mucosa, no significant difference was despite among gender, age and Helicobacter pylori infection status, whereas MR increased rising inflammation scores. The MR of cancer lesions was significantly lower than that of antral non-cancerous mucosa. This finding was not dependent on tumor staging, but also histological classification. In venous invasion, lymph node metastasis, or peritoneal dissemination negative cases, this significant lower MR was also seen.

CONCLUSION

The promoter methylation of PAR2 seems to be increased with a progression of chronic inflammation and has an inhibitory effect on carcinogenesis of the stomach.