Increased c-myb mRNA expression in Barrett's esophagus and Barrett's-associated adenocarcinoma

New 4,5-Diarylimidazol-2-ylidene-iodidogold(I) Complexes with High Activity against Esophageal Adenocarcinoma Cells

Inspired by the vascular-disrupting agent combretastatin A-4 and recently published anticancer active N-heterocyclic carbene (NHC) complexes of Au(I), a series of new iodidogold(I)-NHC complexes was synthesized and characterized. The iodidogold(I) complexes were synthesized by a route involving van Leusen imidazole formation and N-alkylation, followed by complexation with Ag2O, transmetalation with chloro(dimethylsulfide)gold(I) [Au(DMS)Cl], and anion exchange with KI. The target complexes were characterized by IR spectroscopy, 1H and 13C NMR spectroscopy, and mass spectrometry. The structure of 6c was validated via single-crystal X-ray diffraction. A preliminary anticancer screening of the complexes using two esophageal adenocarcinoma cell lines showed promising nanomolar activities for certain iodidogold(I) complexes accompanied with apoptosis induction, as well as c-Myc and cyclin D1 suppression in esophageal adenocarcinoma cells treated with the most promising derivative 6b.

COX-2 strengthens the effects of acid and bile salts on human esophageal cells and Barrett esophageal cells

Aims

Investigate the effect and mechanism of COX-2 on viability, intestinal metaplasia, and atypia in human esophageal squamous and Barrett esophageal cell lines.

Methods

Human esophageal squamous and Barrett esophageal cell lines were transfected with a COX-2 expression vector and a COX-2 siRNA, and then were treated with acid, bile salts, and a mixture of both. Cell viability, the expression of COX-2, NF-κB(p65), CDX-2, MUC2, c-myb, and BMP-4, and the morphology and microstructure of cells were then observed.

Results

The viability of COX-2 overexpressed cells was significantly higher than that of control cells, while the viability of COX-2 siRNA-treated cells was significantly lower than that of control cells. Intestinal metaplasia and atypia were observed in cells overexpressing COX-2. Acid, bile salts, and their mixture inhibited the viability of these two cell lines, but the inhibitory effect of the mixture was stronger than a single treatment in either. SiRNA mediated knockdown of COX-2 strengthened the antiproliferative effects of the mixture on HET-1A and BAR-T cells. The expression of p-p65, CDX-2, and BMP-4 was positively correlated with COX-2 expression, while the expression levels of p65, MUC2, and c-myb remained unchanged.

Conclusion

COX-2 may influence the viability, atypia, and intestinal metaplasia of human esophageal cells and Barrett esophageal cells. Activation of the p-p65, CDX-2, and BMP-4 signaling pathways by COX-2 may be part of this mechanism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-022-00418-5.

MYB Proto-oncogene-like 1-TWIST1 Axis Promotes Growth and Metastasis of Hepatocellular Carcinoma Cells

MYB proto-oncogene-like 1 (MYBL1) has been reported to be a strong activator of transcription and plays an important role in the development of cancer. However, the precise biological function and molecular mechanism of MYBL1 in hepatocellular carcinoma (HCC) cells remain unclear. In the present study, we found that the expression of MYBL1 was markedly overexpressed in HCC cell lines and HCC samples, respectively. Moreover, MYBL1 expression positively correlated with tumor progression and inversely correlated with patient survival in 368 human HCC tissue samples. Overexpression of MYBL1 induced, whereas knockdown of MYBL1 reduced, HCC proliferation and metastasis both in vitro and in vivo. Furthermore, we demonstrated that HCC patients with high MYBL1 expression had significantly shorter overall and poorer disease-free survival than those with low MYBL1 expression. MYBL1 transcriptionally upregulated TWIST1 expression by directly targeting the TWIST1 promoter. More importantly, the in vitro analysis was consistent with the significant correlation between MYBL1 and TWIST1 expression observed in a large cohort of human HCC specimens. Taken together, our results demonstrate that MYBL1 plays an important role in HCC growth and metastasis and reveal a plausible mechanism for upregulation of TWIST1 in HCC.

MYB - A regulatory factor in hematopoiesis

MYB is a transcription factor which was identified in birds as a viral oncogene (v-MYB). Its cellular counterpart was subsequently isolated as c-MYB which has three functional domains - DNA binding domain, transactivation domain and negative regulatory domain. c-MYB is essential for survival, and deletion of both alleles of the gene results in embryonic death. It is highly expressed in hematopoietic cells, thymus and neural tissue, and required for T and B lymphocyte development and erythroid maturation. Additionally, aberrant MYB expression has been found in numerous solid cancer cells and human leukemia. Recent studies have also implicated c-MYB in the regulation of expression of fetal hemoglobin which is highly beneficial to the β-hemoglobinopathies (beta thalassemia and sickle cell disease). These findings suggest that MYB could be a potential therapeutic target in leukemia, and possibly also a target for therapeutic increase of fetal hemoglobin in the β-hemoglobinopathies.

Integrated molecular analysis reveals complex interactions between genomic and epigenomic alterations in esophageal adenocarcinomas

The incidence of esophageal adenocarcinoma (EAC) is rapidly rising in the United States and Western countries. In this study, we carried out an integrative molecular analysis to identify interactions between genomic and epigenomic alterations in regulating gene expression networks in EAC. We detected significant alterations in DNA copy numbers (CN), gene expression levels, and DNA methylation profiles. The integrative analysis demonstrated that altered expression of 1,755 genes was associated with changes in CN or methylation. We found that expression alterations in 84 genes were associated with changes in both CN and methylation. These data suggest a strong interaction between genetic and epigenetic events to modulate gene expression in EAC. Of note, bioinformatics analysis detected a prominent K-RAS signature and predicted activation of several important transcription factor networks, including β-catenin, MYB, TWIST1, SOX7, GATA3 and GATA6. Notably, we detected hypomethylation and overexpression of several pro-inflammatory genes such as COX2, IL8 and IL23R, suggesting an important role of epigenetic regulation of these genes in the inflammatory cascade associated with EAC. In summary, this integrative analysis demonstrates a complex interaction between genetic and epigenetic mechanisms providing several novel insights for our understanding of molecular events in EAC.

GATA6 expression in Barrett's oesophagus and oesophageal adenocarcinoma

BACKGROUND

Barrett's oesophagus can progress towards oesophageal adenocarcinoma through a metaplasia-dysplasia-carcinoma sequence, but the underlying mechanisms are poorly understood. The transcription factor GATA6 is known to be involved in columnar differentiation and proliferation, and GATA6 gene amplification was recently linked with poor survival in oesophageal adenocarcinoma.

AIM

To study the expression of GATA6 during Barrett's oesophagus development and malignant transformation. To determine the prognostic value of GATA6 in oesophageal adenocarcinoma.

METHODS

Two retrospective cohorts were derived from the pathological archive of the University Medical Center Groningen. The first cohort contained 130 tissue samples of normal squamous epithelium, metaplasia, dysplasia and oesophageal adenocarcinoma. The second cohort consisted of a tissue microarray containing tissue from 92 oesophageal adenocarcinoma patients. Immunohistochemistry was used to examine GATA6 protein expression and to correlate GATA6 expression in oesophageal adenocarcinoma with overall and disease-free survival.

RESULTS

The percentage of GATA6-positive cells was low in squamous epithelium (10%) but increased progressively in Barrett's oesophagus (30%, P < 0.001) and high-grade dysplasia (82%, P = 0.005). GATA6 expression was not associated with overall or disease-free survival in oesophageal adenocarcinoma patients (P = 0.599 and P = 0.700 respectively).

CONCLUSION

GATA6 expression is progressively increased during Barrett's oesophagus development and its malignant transformation. However, no prognostic value of GATA6 expression could be found in oesophageal adenocarcinoma.

Expression of p53 upregulated modulator of apoptosis (PUMA) and C-myb in gallbladder adenocarcinoma and their pathological significance

PURPOSE

An increasing number of studies have shown that PUMA and C-myb signaling pathways are involved in various human cancers including colon carcinomas. However, few studies have examined gallbladder cancer specimens, and little is known about the clinical and pathological significance signaling changes may have in gallbladder adenocarcinoma. This study has investigated the expression of PUMA and C-myb in benign and malignant lesions of gallbladder and its pathological significance.

METHODS

Tissue specimens from 108 gallbladder adenocarcinoma patients, 46 adjacent tissues, 15 cases of adenomatous polyps, and 35 surgical specimens from chronic cholecystitis patients were routinely paraffin embedded and sectioned. PUMA and C-myb expressions were detected with EnVision immunohistochemistry.

RESULTS

Positive rates of PUMA and C-myb are significantly higher in gallbladder adenocarcinoma tissues than that in the other three (P < 0.01). Gallbladder epithelial cells in PUMA and/or C-myb positive benign cases manifest moderate to severe atypical dysplasia. Positive rates of PUMA and C-myb in well-differentiated tumors with maximum diameter of <2 cm and with no lymph node metastasis and invasion of the surrounding tissues are significantly lower than that in those poorly differentiated cases with maximum diameter of ≥ 2 cm, lymph node metastasis, and invasion of the surrounding tissues (P < 0.05 or P < 0.01). The postoperative survival of patients whose tumor specimens are positive for PUMA and C-myb is significantly shorter than that of those who are negative for both markers (P < 0.05 or P < 0.01).

CONCLUSIONS

Our results have demonstrated that PUMA and C-myb positive gallbladder tumors progress rapidly, are prone to metastasis, possess strong invasive ability, and have poor prognosis.

Gastrointestinal adenocarcinomas of the esophagus, stomach, and colon exhibit distinct patterns of genome instability and oncogenesis

A more detailed understanding of the somatic genetic events that drive gastrointestinal adenocarcinomas is necessary to improve diagnosis and therapy. Using data from high-density genomic profiling arrays, we conducted an analysis of somatic copy-number aberrations in 486 gastrointestinal adenocarcinomas including 296 esophageal and gastric cancers. Focal amplifications were substantially more prevalent in gastric/esophageal adenocarcinomas than colorectal tumors. We identified 64 regions of significant recurrent amplification and deletion, some shared and others unique to the adenocarcinoma types examined. Amplified genes were noted in 37% of gastric/esophageal tumors, including in therapeutically targetable kinases such as ERBB2, FGFR1, FGFR2, EGFR, and MET, suggesting the potential use of genomic amplifications as biomarkers to guide therapy of gastric and esophageal cancers where targeted therapeutics have been less developed compared with colorectal cancers. Amplified loci implicated genes with known involvement in carcinogenesis but also pointed to regions harboring potentially novel cancer genes, including a recurrent deletion found in 15% of esophageal tumors where the Runt transcription factor subunit RUNX1 was implicated, including by functional experiments in tissue culture. Together, our results defined genomic features that were common and distinct to various gut-derived adenocarcinomas, potentially informing novel opportunities for targeted therapeutic interventions.

Interruption of nuclear localization of ATBF1 during the histopathologic progression of head and neck squamous cell carcinoma

BACKGROUND

The AT-motif binding factor 1 (ATBF1) gene is frequently altered at the genetic level in several types of cancer, but its protein expression and subcellular localization have not been well studied in human cancers, including head and neck squamous cell carcinomas (HNSCCs).

METHODS

ATBF1 expression and localization were examined in 5 cell lines and 197 clinical specimens of HNSCC, and correlated with pathologic and clinical characteristics.

RESULTS

ATBF1 was predominantly localized in the nucleus of hyperplastic squamous epithelium. Whereas nuclear ATBF1 dramatically decreased in invasive tumors (p = .0012), cytoplasmic ATBF1 levels progressively increased from dysplasia to invasive tumors (p < .0001), and the increase correlated with poor survival. Reduced nuclear ATBF1 level was also detected in HNSCC cell lines.

CONCLUSIONS

Nuclear localization of ATBF1 is frequently interrupted in HNSCC, and the interruption is significantly associated with the progression of HNSCC. The cytoplasmic ATBF1 level could be useful for predicting patient survival.

Immunohistochemical study of PUMA, c-Myb and p53 expression in the benign and malignant lesions of gallbladder and their clinicopathological significances

BACKGROUND

Gallbladder cancers have a very poor prognosis without specific molecular marker being identified. In this study we studied PUMA, c-Myb and p53 expression in benign and malignant lesions of gallbladder and analyzed their clinicopathological significance.

METHOD

Immunohistochemical staining of PUMA, c-Myb and p53 protein was performed in 108 gallbladder adenocarcinomas, 46 peritumoral tissues, 15 polyps, and 35 chronic cholecystitis.

RESULTS

We demonstrated that the percent of positive PUMA, c-Myb and p53 expression was significantly higher in gallbladder adenocarcinomas than in peritumoral tissues, polyps and chronic cholecystitis (p < 0.05 or 0.01). Benign gallbladder epithelium with positive PUMA, c-Myb or p53 expression showed moderately or severely atypical hyperplasia. The percent of positive PUMA, c-Myb and p53 expression was significantly higher in the cases having poorly differentiated adenocarcinoma with large tumor mass, lymph node metastasis and high invasiveness than cases with well-differentiated adenocarcinoma with small tumor mass and without metastasis and invasiveness (p < 0.05 or p < 0.01). The percent of positive PUMA, c-Myb and p53 expression was significantly higher in cases with radical resection than without resection (p < 0.05). Univariate Kaplan-Meier analysis showed that PUMA, c-Myb and p53 expression was associated with decreased overall survival (p < 0.05 or p < 0.01). Multivariate Cox regression analysis showed that PUMA, c-Myb or p53 expression was a poor-prognostic predictor in gallbladder adenocarcinoma.

CONCLUSION

PUMA, c-Myb and p53 expression closely relates to the carcinogenesis, fast-progression, easy-metastasis, high-invasion, and poor-prognosis in gallbladder adenocarcinoma.

Gene expression signature analysis identifies vorinostat as a candidate therapy for gastric cancer

BACKGROUND

Gastric cancer continues to be one of the deadliest cancers in the world and therefore identification of new drugs targeting this type of cancer is thus of significant importance. The purpose of this study was to identify and validate a therapeutic agent which might improve the outcomes for gastric cancer patients in the future.

METHODOLOGY/PRINCIPAL FINDINGS

Using microarray technology, we generated a gene expression profile of human gastric cancer-specific genes from human gastric cancer tissue samples. We used this profile in the Broad Institute's Connectivity Map analysis to identify candidate therapeutic compounds for gastric cancer. We found the histone deacetylase inhibitor vorinostat as the lead compound and thus a potential therapeutic drug for gastric cancer. Vorinostat induced both apoptosis and autophagy in gastric cancer cell lines. Pharmacological and genetic inhibition of autophagy however, increased the therapeutic efficacy of vorinostat, indicating that a combination of vorinostat with autophagy inhibitors may therapeutically be more beneficial. Moreover, gene expression analysis of gastric cancer identified a collection of genes (ITGB5, TYMS, MYB, APOC1, CBX5, PLA2G2A, and KIF20A) whose expression was elevated in gastric tumor tissue and downregulated more than 2-fold by vorinostat treatment in gastric cancer cell lines. In contrast, SCGB2A1, TCN1, CFD, APLP1, and NQO1 manifested a reversed pattern.

CONCLUSIONS/SIGNIFICANCE

We showed that analysis of gene expression signature may represent an emerging approach to discover therapeutic agents for gastric cancer, such as vorinostat. The observation of altered gene expression after vorinostat treatment may provide the clue to identify the molecular mechanism of vorinostat and those patients likely to benefit from vorinostat treatment.

Induction of T cell-mediated immunity using a c-Myb DNA vaccine in a mouse model of colon cancer

Overexpression of the proto-oncogene c-Myb occurs in more than 80% of colorectal cancer (CRC) and is associated with aggressive disease and poor prognosis. To test c-Myb as a therapeutic target in CRC we devised a DNA fusion vaccine to generate an anti-CRC immune response. c-Myb, like many tumor antigens, is weakly immunogenic as it is a "self" antigen and subject to tolerance. To break tolerance, a DNA fusion vaccine was generated comprising wild-type c-Myb cDNA flanked by two potent Th epitopes derived from tetanus toxin. Vaccination was performed targeting a highly aggressive, weakly immunogenic, subcutaneous, syngeneic, colon adenocarcinoma cell line MC38 which highly expresses c-Myb. Prophylactic intravenous vaccination significantly suppressed tumor growth, through the induction of anti-tumor immunity for which the tetanus epitopes were essential. Vaccination generated anti-tumor immunity mediated by both CD4+ and CD8+ T cells and increased infiltration of immune effector cells at the tumor site. Importantly, no evidence of autoimmune pathology in endogenous c-Myb expressing tissues was detected as a consequence of breaking tolerance. In summary, these results establish c-Myb as a potential antigen for immune targeting in CRC and serve to provide proof of principle for the continuing development of DNA vaccines targeting c-Myb to bring this approach to the clinic.

MYB function in normal and cancer cells

The transcription factor MYB has a key role as a regulator of stem and progenitor cells in the bone marrow, colonic crypts and a neurogenic region of the adult brain. It is in these compartments that a deficit in MYB activity leads to severe or lethal phenotypes. As was predicted from its leukaemogenicity in several animal species, MYB has now been identified as an oncogene that is involved in some human leukaemias. Moreover, recent evidence has strengthened the case that MYB is activated in colon and breast cancer: a block to MYB expression is overcome by mutation of the regulatory machinery in the former disease and by oestrogen receptor-alpha (ERalpha) in the latter.

Columnar lined (Barrett's) esophagus: future perspectives

Columnar lined esophagus (CLE) or Barrett's esophagus is the precursor for esophageal adenocarcinoma. Future advances in understanding and management of this condition as well as improving the quality of care of CLE patients depends on answering essential questions. It is important to standardize the criteria for CLE definition. The rapid increase in incidence of CLE and adenocarcinoma raises serious concerns that the current management of gastroesophageal reflux disease (GERD) needs reassessment. The risk factors that determine who will and will not develop CLE are as yet undetermined. There is a need to develop a clinical risk stratification tool, which will help in determining who should be screened. The impact of elimination of GERD on the natural history of CLE is one important area for future research. The benefit of surveillance strategies remains unproven and the ideal endoscopic frequency, protocols and markers of cancer risk are unknown. Dysplasia may not provide the gold standard marker of cancer risk because of some inherited problems. A better technique than the current endoscopic pinch biopsy protocol is needed. To overcome the limitations of histological markers, many other markers of cancer risk needs to be developed and validated. The key question as to whether cancer risk is actually reduced by the new ablation modalities remains unanswered. The natural history of dysplasia and its management needs to be clarified. Although many questions have to be answered, it seems, however, that at least some answers exist, and these and proposals for answering some of these questions are underlined throughout this review.

The molecular signature of normal squamous esophageal epithelium identifies the presence of a field effect and can discriminate between patients with Barrett's esophagus and patients with Barrett's-associated adenocarcinoma

BACKGROUND AND AIM

Genetic alterations in the normal tissues surrounding various cancers have been described, but a comprehensive analysis of this carcinogenic field effect in Barrett's-associated adenocarcinoma of the esophagus disease has not been reported. The aim of this study was to analyze the gene expression profile of a panel of highly selected genes in the normal squamous esophagus epihelium of patients with Barrett's esophagus, patients with Barrett's-associated adenocarcinoma, and a healthy control group to define the existence of a carcinogenic field effect, and to investigate the clinical importance of such a field effect in the management of Barrett's disease.

METHODS

Forty-nine histologic normal squamous esophageal epithelia collected from 19 patients with Barrett's esophagus, 20 patients with Barrett's-associated esophageal adenocarcinoma, and a healthy control group of 10 patients were studied. A quantitative real-time reverse transcription-PCR method (TaqMan) was used to measure the expression of a panel of genes with known associations with gastrointestinal carcinogenesis.

RESULTS

A widespread carcinogenic field effect was detected for more than 50% of the genes analyzed including Bax, BFT, CDX2, COX2, DAPK, DNMT1, GSTP1, RARalpha, RARgamma, RXRalpha, RXRbeta, SPARC, TSPAN, and VEGF. Based on the expression signature of the normal appearing squamous esophagus, a linear discriminant analysis was able to distinguish between the three groups of patients with an error rate of 0%.

CONCLUSION

This study provides the first comprehensive investigation of a carcinogenic field effect in Barrett's esophagus disease. Based on the gene expression signature of the normal esophagus, patients could be correctly characterized according to their pathologic classification by applying a linear discriminant analysis. Our results provide evidence that a molecular classification might have clinical importance for the diagnosis and treatment of patients with Barrett's esophagus disease.

Molecular biology of esophageal cancer in the genomics era

The incidence of esophageal adenocarcinoma is rising in the United States and Western countries. Significant differences exist between esophageal adenocarcinoma and squamous cell carcinoma in the molecular mechanisms responsible for the tumorigenesis process. State-of-the-art techniques such as gene microarrays and proteomics will greatly aid in the development of new therapies targeting specific molecular pathways,ultimately leading to improved survival in patients who have esophageal cancer.

Expression of stress response protein glucose regulated protein-78 mediated by c-Myb

Glucose regulated protein-78, GRP78 has been implicated in the protection of tumor cells from cytotoxic damage and apoptosis. When protein profiles of colon cell lines were investigated we found remarkably high GRP78 expression in two cell lines. These cell lines express elevated levels of the transcription factor c-Myb due to genomic amplification of the c-myb locus and we hypothesized that c-Myb regulates GRP78 expression in colon cancer cells. The promoters of human and murine GRP78 and the related family member GRP94 were examined and potential c-Myb binding sites were identified and characterized. DNA binding studies with recombinant c-Myb and nuclear extracts together with ChIP assays on colon cell lines validated these sites. Endogenous GRP78 expression was further induced in these colon cells in response to Thapsigargin treatment, a potent inducer of the unfolded protein response. Transactivation studies with the human GRP78 promoter in colon cell lines showed reporter activity was dependent upon the presence of a conserved c-Myb binding site independent of sequences associated with the unfolded protein response. Finally, over-expression of c-Myb induced the endogenous GRP78 gene. These data suggest that amplification of c-myb in tumor cells may lead to robust GRP78 gene induction, which may in turn assist cells in survival under conditions of oxygen deprivation and nutrient stress.

New Molecular Concepts of Barrett’s Esophagus: Clinical Implications and Biomarkers

Barrett's esophagus (BE) represents the most serious histological consequence of gastroesophageal reflux disease (GERD) that develops in 5-10% of patients with GERD. Given that BE is the only known precursor to esophageal adenocarcinoma (EA), a systematic endoscopic biopsy protocol can detect EAs at an early stage. However, endoscopic and histopathological evaluation of BE are not adequate for effective screening of high risk patients. Therefore, molecular abnormalities associated with BE have been considered as surrogate markers and their use as such is proposed. Flow cytometry is the most useful adjunct to histology, and ploidy status of BE is an independent risk factor. Cyclin D1 overexpression is inversely correlated with survival in EA. C-erbB2 (+) patients have poorer prognosis. High plasma adenomatous polyposis coli levels correlate with reduced patient survival. p53 expression allows patient risk for EA stratification. Nuclear factor-kappaB overexpression inversely correlates with good response to adjuvant chemotherapy and radiotherapy in EA. Patients with cyclooxygenase-2 overexpression have reduced survival rates. Increased E-cadherin staining is associated with shorter survival in EA patients who received chemoradiotherapy. Finally, existing data cannot rule out a correlation between EA and colorectal tumors. Seventeen BE molecular alterations yielded noteworthy clinical implications. Apart from endoscopy and histology, these data allow for better risk stratification for patients with BE and for more efficient and timely therapeutic approaches.

A multigene expression panel for the molecular diagnosis of Barrett's esophagus and Barrett's adenocarcinoma of the esophagus

In order to identify genes or combination of genes that have the power to discriminate between premalignant Barrett's esophagus and Barrett's associated adenocarcinoma, we analysed a panel of 23 genes using quantitative real-time RT-PCR (qRT-PCR, Taqman and bioinformatic tools. The genes chosen were either known to be associated with Barrett's carcinogenesis or were filtered from a previous cDNA microarray study on Barrett's adenocarcinoma. A total of 98 tissues, obtained from 19 patients with Barrett's esophagus (BE group) and 20 patients with Barrett's associated esophageal adenocarcinoma (EA group), were studied. Triplicate analysis for the full 23 gene of interest panel, and analysis of an internal control gene, was performed for all samples, for a total of more than 9016 single PCR reactions. We found distinct classes of gene expression patterns in the different types of tissues. The most informative genes clustered in six different classes and had significantly different expression levels in Barrett's esophagus tissues compared to adenocarcinoma tissues. Linear discriminant analysis (LDA) distinguished four genetically different groups. The normal squamous esophagus tissues from patients with BE or EA were not distinguishable from one another, but Barrett's esophagus tissues could be distinguished from adenocarcinoma tissues. Using the most informative genes, obtained from a logistic regression analysis, we were able to completely distinguish between benign Barrett's and Barrett's adenocarcinomas. This study provides the first non-array parallel mRNA quantitation analysis of a panel of genes in the Barrett's esophagus model of multistage carcinogenesis. Our results suggest that mRNA expression quantitation of a panel of genes can discriminate between premalignant and malignant Barrett's disease. Logistic regression and LDAs can be used to further identify, from the complete panel, gene subsets with the power to make these diagnostic distinctions. Expression analysis of a limited number of highly selected genes may have clinical usefulness for the treatment of patients with this disease.

Role of retinoid X receptor mRNA expression in Barrett's esophagus

The Barrett's multistage process is characterized histopathologically by progression from Barrett's intestinal metaplasia to Barrett's esophagus with dysplasia and ultimately adenocarcinoma. Understanding of the molecular alterations in this multistage process may contribute to improved diagnosis and treatment. Retinoid X receptors (RXR) play an important role in regulating the morphogenesis, development, growth, and differentiation of cells. Alterations in RXR expression have been observed in a variety of solid tumors; however, the role in Barrett's esophagus disease has yet to be determined. The aim of this study was to assess the prevalence and timing of RXR messenger RNA expression in the Barrett's metaplasia-dysplasia-adenocarcinoma sequence and to investigate its role in the development and progression of this disease. We analyzed the mRNA expression of all three RXR subtypes (RXR-alpha, RXR-beta, and RXR-gamma) by using a quantitative real-time reverse transcription-polymerase chain reaction method in 108 specimens from 19 patients with Barrett's esophagus without carcinoma (BE group), 20 patients with Barrett's-associated adenocarcinoma (EA group), and a control group of 10 patients without evidence of gastroesophageal reflux disease (CG). RXR-alpha mRNA expression was significantly decreased (P < 0.001; Kruskal-Wallis test), and RXR-gamma was significantly increased (P < 0.001) at higher stages in Barrett's esophagus. RXR-beta expression was highest in Barrett's tissues and was significantly increased compared to normal squamous tissues (P=0.01; Wilcoxon test) and adenocarcinoma tissues (P=0.018, Mann-Whitney test). RXR-alpha and RXR-beta mRNA expression was significantly associated in normal squamous esophagus tissues (r(2)=0.49; P < 0.001; Spearman test), Barrett's tissues (r(2)=0.63; P < 0.001), and adenocarcinoma tissues (r(2)=0.68; P=0.001). There were significant differences in RXR-alpha (P=0.011) and RXR-beta (P=0.005) mRNA expression in histopathologically normal squamous esophagus tissues in patients with cancer and the control group without evidence of gastroesophageal reflux disease. These findings suggest that alterations in the mRNA expression of all three RXR subtypes are frequent events in the development and progression of Barrett's esophagus and associated adenocarcinoma, that RXR mRNA expression levels may be useful biomarkers for this disease, and that a widespread "field-effect" is present in the normal esophagus of patients with esophageal adenocarcinoma.

c-myb Heterozygous Mice Are Hypersensitive to 5-Fluorouracil and Ionizing Radiation

Hypersensitivity to chemo- and radiotherapy employed during cancer treatment complicates patient management. Identifying mutations in genes that compromise tissue recovery would rationalize treatment and may spare hypersensitive patients undue tissue damage. Genes that govern stem cell homeostasis, survival, and progenitor cell maintenance are of particular interest in this regard. We used wild-type and c-myb knock-out mice as model systems to explore stem and progenitor cell numbers and sensitivity to cytotoxic damage in two radiosensitive tissue compartments, the bone marrow and colon. Because c-myb null mice are not viable, we used c-myb heterozygous mice to test for defects in stem-progenitor cell pool recovery following γ-radiation and 5-fluorouracil treatment, showing that c-myb+/− mice are hypersensitive to both agents. While apoptosis is comparable in mutant and wild-type mice following radiation exposure, the crypt beds of c-myb+/− mice are markedly depleted of proliferating cells. Extrapolating from these data, we speculate that acute responses to cytotoxic damage in some patients may also be attributed to compromised c-myb function.

Differential SPARC mRNA expression in Barrett's oesophagus

Barrett's oesophagus (BE) is the precursor lesion to adenocarcinoma of the oesophagus. Understanding of the molecular alterations in this multistage process may contribute to improved diagnosis and treatment. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein that modulates cell adhesion and growth. Alterations in SPARC expression have been observed in a variety of solid tumours. The aim of this study was to assess the prevalence and timing of SPARC mRNA expression in Barrett's multistage disease and to investigate the impact of SPARC alterations on the development and progression of this disease. SPARC mRNA expression was measured using a quantitative real-time RT-PCR method in 108 specimens from 19 patients with BE without carcinoma, 20 patients with Barrett's-associated adenocarcinoma (EA), and a control group (CG) of 10 patients without evidence of gastro-oesophageal reflux disease. The median SPARC mRNA expression was significantly upregulated in BE tissues compared to paired normal oesophagus (NE) tissues for the BE group (P=0.004) and for the EA group (P<0.001). The SPARC mRNA expression was significantly higher in adenocarcinoma of the oesophagus compared to matching NE tissue and compared to Barrett's tissues in the EA group (P<0.001). Furthermore, SPARC expression values were significantly different between metaplastic and dysplastic Barrett's tissues (P=0.014). In histologically normal squamous oesophagus tissues obtained from carcinoma patients (EA group), the SPARC mRNA expression was significantly higher compared to NE mucosa from the BE group and the CG group (P=0.03). These findings suggest that the upregulation of SPARC mRNA expression is an early event in the development and progression of BE and EA, and that high SPARC expression may be a clinically useful biomarker for the detection of occult adenocarcinoma, and that a widespread 'field effect' is present in the NE of patients with oesophageal adenocarcinoma.

Defining dysplasia in Barrett esophagus

Histologic grading of esophageal biopsies remains the cornerstone of management in patients with Barrett esophagus. This remains true despite ongoing research into the genetic abnormalities that occur in the setting of intestinal metaplasia, dysplasia, and adenocarcinoma of the esophagus. As of this writing, there are no objective tests that can replace the pathologist's eyes in predicting prognosis in this setting. However, pathologists and clinicians are well aware that the histologic interpretation of biopsies is an inherently subjective practice. The validity of this exercise depends entirely on the experience of the pathologist. Having said that, two interobserver studies on the grading of dysplasia in Barrett esophagus suggest that, if published criteria are adhered to, the histologic grading of dysplasia is a useful tool in patient management. In this review, the updated pathologic criteria for each category of dysplasia are presented, and the results of two large interobserver variability studies are reviewed.

Targeting c-Myb expression in human disease

c-Myb is a transcription factor employed in the haematopoietic system and gastrointestinal tract to regulate the exquisite balance between cell division, differentiation and survival. In its absence, these tissues either fail to form, or show aberrant biology. Mice lacking a functional c-myb gene die in utero by day 15 of development. When inappropriately expressed, as is common in leukaemia and epithelial cancers of the breast, colon and gastro-oesophagus, c-Myb appears to activate gene targets of key importance to cancer progression and metastasis. These genes include cyclooxygenase-2 (COX-2), Bcl-2, BclX(L) and c-Myc, which influence diverse processes such as angiogenesis, proliferation and apoptosis. The clinical potential for blocking c-Myb expression in malignancies is based upon strong preclinical data and some trial-based evidence. The modest clinical experience to date has been with haematopoietic malignancies, but other disease classes may be amenable to similar interventions. The frontline agents to achieve this are nuclease-resistant oligodeoxynucleotides (ODNs), which are proving to be acceptable therapeutic reagents in terms of tolerable toxicities and delivery. Nevertheless, further effort must be focused on improving their efficacy, eliminating non-specific toxicity and optimising delivery. Optimisation issues aside, it would appear that anti-c-Myb therapies will be used with most success when combined with other agents, some of which will be established cytotoxic and differentiation-inducing drugs. This review will explore the future strategic use of ODNs in vivo, focusing on a wide spectrum of diseases, including several beyond the haematopoietic malignancies, in which c-Myb appears to play a role.

Cellular and molecular mechanisms responsible for progression of Barrett's metaplasia to esophageal carcinoma

Barrett's metaplasia is found in approximately 12% to 18% of patients undergoing upper endoscopy for symptoms of reflux. Barrett's metaplasia is a premalignant condition and remains the number one risk factor for developing esophageal adenocarcinoma. There has been an increase in the incidence of esophageal adenocarcinoma in the past two decades, making it the most rapidly rising cancer in the United States and Western Europe. This article describes the progression from Barrett's metaplasia to esophageal adenocarcinoma and predictors for the development of adenocarcinoma in Barrett's metaplasia. Barrett's metaplasia represents a histological mosaic, with dysplastic tissue adjacent to non-dysplastic tissue. The histologic changes leading to adenocarcinoma are accompanied by alterations at the molecular level, including the accumulation of gene mutations and changes in gene expression. The determination of the molecular events that occur in the transition from normal esophageal squamous mucosa to dysplasia and to esophageal adenocarcinoma have lead to a better understanding of the process of the transformation to adenocarcinoma. This knowledge will lead to better biomarkers to diagnose and assess cancer risk.

Glutathione S-transferase-pi expression is downregulated in patients with Barrett's esophagus and esophageal adenocarcinoma

The glutathione S-transferases (GSTs) are a family of enzymes that play an important role in the prevention of cancer by detoxifying numerous potentially carcinogenic compounds. GSTs conjugate reduced glutathione to a variety of electrophilic and hydrophobic compounds, converting them into more soluble, more easily excretable compounds. Decreased glutathione S-transferase-pi (GSTPI) enzyme activity has been reported in Barrett's esophagus, and an inverse correlation was demonstrated between GST enzyme activity and tumor incidence in the gastrointestinal tract, but the role of GSTPI messengerRNA (mRNA) expression in Barrett's esophagus and associated adenocarcinomas is uncertain. The purpose of this study was to investigate the role of GSTPI mRNA and protein expression in the development and progression of the Barrett's metaplasia-dysplasia-adenocarcinoma sequence, and to investigate the potential of GSTPI quantitation as a biomarker in the clinical management of this disease. GSTPI mRNA expression levels, in relation to the housekeeping gene beta-actin, were analyzed using a quantitative real-time reverse transcription-polymerase chain reaction method (TaqMan) in 111 specimens from 19 patients with Barrett's esophagus without carcinoma (BE group), 21 patients with Barrett's-associated adenocarcinoma (EA group), and a control group of 10 patients without evidence of Barrett's esophagus or chronic gastroesophageal reflux disease. GSTPI mRNA expression was detectable in all 111 samples investigated. Analyzed according to histopathologic group, the median GSTPI mRNA expression was highest in normal squamous esophagus epithelium, intermediate in Barrett's esophagus, and lowest in adenocarcinoma tissues (P < 0.001). The median GSTPI expression was significantly decreased in Barrett's esophagus tissues compared to matching normal squamous esophagus from either the BE group (P = 0.001) or the EA group (P = 0.023). GSTPI expression levels in adenocarcinoma tissues were decreased compared to matching normal esophagus tissues from the patients with adenocarcinoma (P = 0.011). Furthermore, GSTPI mRNA expression values were significantly different between metaplastic, dysplastic, and adenocarcinoma tissues (P = 0.026). GSTPI expression levels were also significantly lower in histologically normal squamous esophagus tissues from patients with cancer (EA group) compared to both normal esophagus tissues from patients without cancer (BE group; P = 0.007) and normal esophagus tissues from the control group with no esophageal abnormality (P = 0.002). GSTPI protein expression was generally highest in the basal layer of normal squamous esophagus epithelium and lowest in adenocarcinoma cells, with Barrett's cells showing intermediate staining intensity. Our results show that downregulation of GSTPI expression is an early event in the development of Barrett's esophagus and esophageal adenocarcinoma. Loss of GSTPI expression may have an important role in the development and progression of this disease.