Experimental and clinic-opathologic study on the relationship between transcription factor Egr-1 and esophageal carcinoma

Comprehensive analysis of normal adjacent to tumor transcriptomes

Histologically normal tissue adjacent to the tumor (NAT) is commonly used as a control in cancer studies. However, little is known about the transcriptomic profile of NAT, how it is influenced by the tumor, and how the profile compares with non-tumor-bearing tissues. Here, we integrate data from the Genotype-Tissue Expression project and The Cancer Genome Atlas to comprehensively analyze the transcriptomes of healthy, NAT, and tumor tissues in 6506 samples across eight tissues and corresponding tumor types. Our analysis shows that NAT presents a unique intermediate state between healthy and tumor. Differential gene expression and protein–protein interaction analyses reveal altered pathways shared among NATs across tissue types. We characterize a set of 18 genes that are specifically activated in NATs. By applying pathway and tissue composition analyses, we suggest a pan-cancer mechanism of pro-inflammatory signals from the tumor stimulates an inflammatory response in the adjacent endothelium.

Normal tissue adjacent to the tumour (NAT) is often used as a control in cancer studies. Here, the authors analyse across cancer types the transcriptomes of healthy, NAT, and tumour tissues, and find that NAT presents a unique state, potentially due to inflammatory response of the NAT to the tumour tissue.

CBX7 modulates the expression of genes critical for cancer progression

Background

We have previously shown that the expression of CBX7 is drastically decreased in several human carcinomas and that its expression progressively decreases with the appearance of a highly malignant phenotype. The aim of our study has been to investigate the mechanism by which the loss of CBX7 expression may contribute to the emergence of a more malignant phenotype.

Methods

We analyzed the gene expression profile of a thyroid carcinoma cell line after the restoration of CBX7 and, then, analyzed the transcriptional regulation of identified genes. Finally, we evaluated the expression of CBX7 and regulated genes in a panel of thyroid and lung carcinomas.

Results

We found that CBX7 negatively or positively regulates the expression of several genes (such as SPP1, SPINK1, STEAP1, and FOS, FOSB, EGR1, respectively) associated to cancer progression, by interacting with their promoter regions and modulating their transcriptional activity. Quantitative RT-PCR analyses in human thyroid and lung carcinoma tissues revealed a negative correlation between CBX7 and its down-regulated genes, while a positive correlation was observed with up-regulated genes.

Conclusion

In conclusion, the loss of CBX7 expression might play a critical role in advanced stages of carcinogenesis by deregulating the expression of specific effector genes.

Identification of potential biomarkers from microarray experiments using multiple criteria optimization

Microarray experiments are capable of determining the relative expression of tens of thousands of genes simultaneously, thus resulting in very large databases. The analysis of these databases and the extraction of biologically relevant knowledge from them are challenging tasks. The identification of potential cancer biomarker genes is one of the most important aims for microarray analysis and, as such, has been widely targeted in the literature. However, identifying a set of these genes consistently across different experiments, researches, microarray platforms, or cancer types is still an elusive endeavor. Besides the inherent difficulty of the large and nonconstant variability in these experiments and the incommensurability between different microarray technologies, there is the issue of the users having to adjust a series of parameters that significantly affect the outcome of the analyses and that do not have a biological or medical meaning. In this study, the identification of potential cancer biomarkers from microarray data is casted as a multiple criteria optimization (MCO) problem. The efficient solutions to this problem, found here through data envelopment analysis (DEA), are associated to genes that are proposed as potential cancer biomarkers. The method does not require any parameter adjustment by the user, and thus fosters repeatability. The approach also allows the analysis of different microarray experiments, microarray platforms, and cancer types simultaneously. The results include the analysis of three publicly available microarray databases related to cervix cancer. This study points to the feasibility of modeling the selection of potential cancer biomarkers from microarray data as an MCO problem and solve it using DEA. Using MCO entails a new optic to the identification of potential cancer biomarkers as it does not require the definition of a threshold value to establish significance for a particular gene and the selection of a normalization procedure to compare different experiments is no longer necessary.

Expression of Egr-1 gene and its correlation with the oncogene proteins in non-irradiated and irradiated esophageal squamous cell carcinoma

We study the expression of early growth response gene-1 (Egr-1 gene) in non-irradiated and irradiated human esophageal cancer tissues, and its relationship with the expression of C-fos, C-jun onco-proteins as well as Egr-1 target gene proteins P53, Rb and Bax expression. In situ hybridization (ISH) and immunohistochemistry (IHC) were used respectively to detect Egr-1 mRNA, Egr-1, C-fos, C-jun, P53, Rb and Bax proteins in 80 surgically resected non-irradiated and irradiated tumor specimens of esophageal squamous cell carcinoma. Egr-1 gene mRNA and Bax protein were located in the cytoplasm, whereas Egr-1, C-fos, C-jun, P53, Rb proteins were located in the nuclei. Egr-1 was expressed in nine out of 40 cases (22.5%) of non-irradiated and 23 of 40 cases (57.5%) of irradiated tumor specimens. No correlation was found between Egr-1 gene expression and C-fos, C-jun onco-proteins expression, neither was any correlation disclosed between Egr-1 gene expression with its target gene protein expression. Patients who underwent radiotherapy with Egr-1 overexpressed in their cancer tissue had better prognosis. Radiotherapy up-regulates Egr-1 expression in esophageal carcinoma. Egr-1 overexpression may be a potential radiation response gene marker and may play an important role in prognosis of esophageal squamous cell carcinoma.

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The Cytoskeleton Differentially Localizes the Early Growth Response Gene-1 Protein in Cancer and Benign Cells of the Prostate

Prostate cancer is the most prevalent malignancy and the second leading cause of cancer mortality in men. Early growth response gene-1 (EGR-1) plays a crucial role in the development and progression of prostate cancer. The presented data show that EGR-1 differs in cellular localization in benign cells compared with malignant prostate cells and that this localization is critical for the transcriptional activation of EGR-1-dependent genes. Immunohistochemistry of human prostate cancer specimens demonstrated higher levels of EGR-1 in malignant cells located predominantly in the cytoplasm, whereas benign cells contained lower levels of EGR-1 located predominantly in the nucleus. Benign prostate cells responded to mitogens in vitro, with increased levels of EGR-1, rapid nuclear translocation, and enhanced transcriptional activity, whereas malignant prostate cells did not exhibit the same responses, and the protein remained in the cytoplasm. The central aspect of this difference is the association of EGR-1 with microtubules, which is exclusive to the benign cells of the prostate and is requisite for the nuclear translocation and transcriptional activity of EGR-1. Our in vitro data demonstrate that the differences in EGR-1 between benign and malignant prostate cells extend beyond cellular levels, which was confirmed by immunohistochemistry in human tissues. Thus, we add the novel concept that microtubules regulate EGR-1 localization in benign prostate cells but not in malignant prostate cells.

Inhibition of adenovirus-mediated p27kip1 gene on growth of esophageal carcinoma cell strain

AIM: To investigate the inhibition of p27kip1 gene on the growth of esophageal carcinoma cell strain (EC9706).

METHODS: Recombinant adenovirus Ad-p27kip1 was constructed and transfected into esophageal carcinoma cell EC-9706, and its effect on p27kip1 expression, the growth of esophageal carcinoma cell, DNA replication, protein synthesis, cell multiplication and apoptosis were explored by means of cell growth count, ³H-TdR, ³H-Leucine incorporation, flow cytometry, DNA fragment analysis and TUNEL.

RESULTS: Recombinant adenovirus Ad-p27kip1 was successfully constructed with a virus titer of 1.24 × 10¹² pfu/mL. p27kip protein expression increased markedly after EC-9706 transfection, while incorporation quantity of ³H-TdR and ³H-Leucine decreased significantly. The growth of esophageal carcinoma cell was inhibited obviously. Testing of flow cytometry displayed a typical apoptosis peak, and DNA gel electrophoresis showed a typical apoptosis ladder. TUNEL showed the apoptosis rate of Ad-p27kip1 group and control group to be 37.3% and 1.26% (P < 0.001) respectively.

CONCLUSION: Ad-p27kip1 can inhibit the growth and multiplication of esophageal carcinoma cells and induce apoptosis. Therefore, enhanced p27kip1 expression may be a new way to treat esophageal carcinoma.

Separation and identification of differentially expressed nuclear matrix proteins between human esophageal immortalized and carcinomatous cell lines

AIM: To separate and identify differentially expressed nuclear matrix proteins (NMPs) between the immortalized human esophageal epithelial cell line (SHEE) and the malignantly transformed esophageal carcinoma cell line (SHEEC), and to provide new ways for finding specific markers and the pathogenesis of esophageal carcinoma.

METHODS: SHEE and SHEEC cell lines were used to extract NMPs. The quality of NMPs was monitored by Western blot analysis including DNA topoisomerase IIα, proliferation cell nuclear antigen (PCNA) and histone. NMPs of SHEE and SHEEC were analyzed by two-dimensional electrophoresis (2-DE), silver staining and PDQuest6.2 image analysis software. Three spots in which the differentially expressed NMPs were more obvious, were selected and analyzed with matrix-assisted laser desorption/ionization time of flying mass spectrometry (MALDI-TOF-MS) and database search.

RESULTS: Western blot analysis revealed that DNA topoisomerase IIα and PCNA were detected, and the majority of histones were deleted in NMPs of SHEE and SHEEC. After 2-DE image analysis by PDQuest6.2 software, the 2-DE maps were detected with an average of 106 ± 7.1 spots in SHEE and 132 ± 5.0 spots in SHEEC. Most of them were matched one another (r = 0.72), only 16 protein spots were found differing in intensity. Three NMPs including cytoskeletal tropomyosin, FK506-binding protein 6, similar to retinoblastoma binding protein 8 were preliminarily identified by MALDI- TOF-MS.

CONCLUSION: These differentially expressed NMPs may play an important role during malignant transformation from SHEE to SHEEC. Their separation and identification will contribute to searching for specific markers and probing into the pathogenesis of esophageal carcinoma.

Inhibitory effect of p27kip1 mediated by adenovirus on model of esophageal carcinoma in nude mice

AIM

To investigate the inhibitory effect of p27kip1 mediated by adenovirus vector on esophageal carcinoma in vivo.

METHODS

Eca109 cells were injected into the subcutaneous tissue of nude mice to establish tumors. The transplanted tumors were reproduced among the nude mice contionually after original grafts grew well. The model of esophageal carcinoma in nude mice was established by transplanting the tumor tissue mass into the subcutaneous tissue of nude mice .The successful constructed recombinant adenoviral vector carrying p27kip1 gene and LacZ recombinant adenovirus were directly injected into the esophageal tumors in nude mice respectively. Compared with control group, the growth curves of tumor were drawed and the growth inhibition rates of tumor were calculated.

RESULTS

The growth of tumors in gene therapy group with p27kip1 was obviously suppressed, which had a significant difference compared with control group (P < 0.001). The growth inhibition rate of tumor reached 64.1%.

CONCLUSION

p27kip1 gene therapy mediated by adenovirus vector has significant inhibitory effect on esophageal carcinoma in vivo.

Effect of expression of interferon-g gene in inhibition of growth of colon cancer cell

AIM: To investigate the effect of expression of interferon-γ(IFN-γ) in tumor cell and its inhibitory effect on the growth of tumor cell.

METHODS: pcDNA3-IFN-γ vector containing IFN- γ gene was constructed and transfected into LOVO, SW620, HCT116BG and Hela cell lines by lipofectamine, respectively. The expression of IFN-γ, CEA and HLA-DR in transfected cells were tested. Both the number of apoptosis of and the proportion of cell cycles of tumor cells were measured to investigate the anti-tumor effect of IFN-γ gene therapy.

RESULTS: LOVO and HCT116BG transfected cell lines had high expression of CEA, the average level of CEA was significantly increased from 26.02±6.76 to 38.85±7.07 mg/L (P < 0.05). However, there was no detectable increase in the supernatants of Hela, SW620 cell lines that naturally expressed little of CEA. Flow cytometry analysis showed that HLA-DR expression rate (11.67±7.20) was significantly higher than that prior gene transfection (3.91±3.61) (P < 0.01), and the IFN-γ gene transfer effectively induced the apoptosis of tumor cells, the proportion of DNA synthesis phase was deceased gradually after IFN-γ gene transfer, which indicated that the synthesis of DNA and growth of tumor cells were repressed.

CONCLUSION: IFN-γ gene therapy enhanced the expression of antigens on cell surface and thus induced powerful antitumor immunity. Repressing of synthesis of DNA, inducing the apoptosis of tumor cells and inhibiting the proliferation of tumor cells might be anti-tumor mechanisms of IFN-γ.

HLA-DRB1 allele polymorphisms in genetic susceptibility to esophageal carcinoma

AIM: To probe into the genetic susceptibility of HLA-DRB1 alleles to esophageal carcinoma in Han Chinese in Hubei Province.

METHODS: HLA-DRB1 allele polymorphisms were typed by polymerase chain reaction with sequence-specific primers (PCR-SSP) in 42 unrelated patients with esophageal cancer and 136 unrelated normal control subjects and the associated HLA-DRB1 allele was measured by nucleotide sequence analysis with PCR.SAS software was used in statistics.

RESULTS: Allele frequency (AF) of HLA-DRB1*0901 was significantly higher in esophageal carcinoma patients than that in the normal controls (0.2500 vs 0.1397, P = 0.028, the odds ratio 2.053, etiologic fraction 0.1282). After analyzed the allele nucleotide sequence of HLA-DRB1*0901 which approachs to the corresponded exon 2 sequence of the allele in genebank. There was no association between patients and controls in the rested HLA-DRB1 alleles.

CONCLUSION: HLA-DRB1*0901 allele is more common in the patients with esophageal carcinoma than in the healthy controls, which is positively associated with the patients of Hubei Han Chinese. Individuals carrying HLA-DRB1*0901 may be susceptible to esophageal carcinoma.

An analysis of esophageal cancer incidence in Cixian county from 1974 to 1996

AIM: To describe the incidence of esophageal cancer (EC) in Cixian, a county of Hebei province during 1974-1996. We analyzed the sex and age characteristics as well as the geographic distribution of EC, in order to determine the impact so that methods of preventing and controlling EC in Cixian can be put in place.

METHODS: Since the early 1970s, the cancer registry system has been established, which collects the cancer incidence in Cixian county. The malignant tumors were coded according to International Classification of Disease IX (ICD-9). All the data were checked and analyzed using EPIINFO.

RESULTS: The trend of the incidence rate of EC from 1974 to 1996 had declined, (229.9/100000 vs 178.5/100000, Odds ratio = 1.47, 95% CI:1.32~1.63, χ² = 52.89. trend χ² = 26.54, P < 0.001). The incidence rate of males declined significantly (281.81/100000 vs 157.96/100000, Odds ratio = 1.61, 95% CI: 1.41~1.84, χ² = 47.85. Trend χ² = 44.86, P < 0.001), whereas, the females remained steady (157.96/100000 vs 133.41/100000, odds ratio = 1.28, 95% CI:1.17~1.49, χ² = 9.26. trend χ² = 2.69, P > 0.05). Male average annual incidence rate was 142.80/100000 and the female's was 95.18/100000. The sex ratio (males to females) was 1.50:1. The incidence rate was increasing along with the age. As to the geographic distribution, the incidence rate in mountainous areas and hilly areas showed a significantly declining trend (mountainous areas, trend χ² = 149.93, P < 0.001; hilly areas, trend χ² = 42.70, P < 0.001). The incidence rate of EC in plain areas had increased (trend χ² = 22.39, P < 0.001).

CONCLUSION: The incidence rate of EC in Cixian county shows a trend and has declined after two decades, especially in mountainous area. But compared to other regions in the world, Cixian county still had a high incidence rate of EC.

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

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

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

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

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

Identification of differentially expressed proteins between human esophageal immortalized and carcinomatous cell lines by two-dimensional electrophoresis and MALDI-TOF-mass spectrometry

AIM: To identify the differentially expressed proteins between the human immortalized esophageal epithelial cell line (SHEE) and the malignant transformed esophageal carcinoma cell line (SHEEC), and to explore new ways for studying esophageal carcinoma associated genes.

METHODS: SHEE and SHEEC cell lines were used to separate differentially expressed proteins by two-dimensional electrophoresis. The silver-stained 2-D gels was scanned with EDAS290 digital camera system and analyzed with the PDQuest 6.2 Software. Six spots in which the differentially expressed protein was more obvious were selected and analyzed with matrix-assisted laser desorption/ionization time of flying mass spectrometry (MALDI-TOF-MS).

RESULTS: There were 107±4.58 and 115±9.91 protein spots observed in SHEE and SHEEC respectively, and the majority of these spots between the two cell lines matched each other (r = 0.772), only a few were expressed differentially. After analyzed by MALDI-TOF-MS and database search for the six differentially expressed proteins, One new protein as well as other five sequence-known proteins including RNPEP-like protein, human rRNA gene upstream sequence binding transcription factor, uracil DNA glycosylase, Annexin A2 and p300/CBP-associated factor were preliminarily identified.

CONCLUSION: These differentially expressed proteins might play an importance role during malignant transformation of SHEEC from SHEE. The identification of these proteins may serve as a new way for studying esophageal carcinoma associated genes.