[Rapid Discriminantion of Common Leather Varieties by Near Infrared Spectroscopy].

Rapid classification of leather variety means important to product process control, trading process and market surveillance. There is no official detection standard on classification of leather variety for the present. By now the testers use organoleptic method, burning method, chemical dissolution method, microscope method, or combination of them, to give a convincing result. The testers are required to highly sufficiently experienced, and not influenced by subjective factors. It also costs too much time. For the purpose of this research, spectra of five common varieties of leather samples (full-grain leather, split leather, sheep leather, reborn leather and manmade leather) were collected from market. Discriminant analysis combined with pre-processing method, including multiplicative signal correction (MSC), standard normal variate (SNV), first derivative and second derivative were used to classify the spectra above. It shows that the above five varieties of leather overlapped seriously in the same space. But manmade leather can be easily distinguished from the other four leather varieties using rear spectra, with the misclassified percent of 1.2%. The last four leather varieties covered each other partly in the same space, classify of any two of them can reach a lower misclassified percent, about 1.3%～17.9%. Different pre-processing method affected the discriminantion model positively or negatively with no regularity. None of these pre-processing methods was found to give a positive effect in a stable and persistent way. It can be concluded that it is feasible to discriminate the common leather varieties by near infrared Spectroscopy. All of the samples were taken from the finish products in the market (eg, handbag, belt, leather coat), which were processed in different ways (eg. tanning, knurling, dyeing). The different processes of the samples could bring an unforeseeable influence to the model which may be reduced by some method, for example, increasing the number and variety of samples.

[Distribution of heavy metals in Xiangsi River Valley of Tongling, China].

The Xiangsi River valley was selected to study the distribution of heavy metals in mining area. Waste rocks, soils, sediments and waters of Xiangsi River valley were sampled. The concentrations of Cu, Pb, Zn, Cd, Cr, As and Hg were analyzed. The possibility of generating acid drainage of the waste rocks was studied. Meanwhile, the speciation of Pb and Cr in waste rocks was analyzed by the five-step sequential chemical extract method developed by Fortsner. And then the distribution of heavy metals in various samples was summarized, and the ecological risk of heavy metals in mining area was discussed. The results indicated that the waste rocks of Fenghuangshan copper mine upriver barely generated acid mine drainage (AMD). But the waste rocks of Xinqiao pyrite mine in the middle area generated AMD. The content of sulfide mineral rich of heavy metals was lower and the content of CaO was higher in the waste rocks of Fenghuangshan copper mine, resulting in the different AMD generation ability. The contents of heavy metals in waste rocks were higher, and the deoxidization of Pb and Cr was positively correlated with their concentrations in waste rocks. The results indicated that heavy metals in waste rocks would be most likely dissolved in AMD and then contaminate the environment. There was obvious regularity in the distributions of heavy metals in soils, sediments and waters of Xiangsi river valley. The concentrations of heavy metals upriver were lower than those of corresponding national standards and elements background values. But there was obvious heavy metal contamination in the middle area. It was shown that the mining activities of Xinqiao pyrite mine in the middle area had ecological harm to the surrounding environment. And mining enterprises should pay attention to the emissions of mining wastes and the treatment of AMD.

B-cell lymphoma 6 protein stimulates oncogenicity of human breast cancer cells.

BACKGROUND: B-cell lymphoma 6 (BCL6) protein, an evolutionarily conserved zinc finger transcription factor, showed to be highly expressed in various human cancers in addition to malignancies in the lymphoid system. This study investigated the role of BCL6 expression in breast cancer and its clinical significance in breast cancer patients. METHODS: Expression of BCL6 protein was assessed using in situ hybridization and immunohistochemistry in 127 breast cancer patients and 50 patients with breast benign disease as well as in breast cell lines. Expression of BCL6 was restored or knocked down in two breast cancer cell lines (MCF-7 and T47D) using BCL6 cDNA and siRNA, respectively. The phenotypic change of these breast cancer cell lines was assessed using cell viability MTT, Transwell invasion, colony formation, and flow cytometry assays and in a xenograft mice model. Luciferase reporter gene, immunoblot, and qRT-PCR were used to investigate the molecular events after manipulated BCL6 expression in breast cancer cells. RESULTS: BCL6 protein was highly expressed in breast cancer cell lines and tissue specimens and expression of BCL6 protein was associated with disease progression and poor survival of breast cancer patients. In vitro, the forced expression of BCL6 results in increased proliferation, anchorage-independent growth, migration, invasion and survival of breast cancer cell lines, whereas knockdown of BCL6 expression reduced these oncogenic properties of breast cancer cells. Moreover, forced expression of BCL6 increased tumor growth and invasiveness in a nude mouse xenograft model. At the gene level, BCL6 was a target gene of miR-339-5p. Expression of BCL6 induced expression of CXCR4 and cyclinD1 proteins. CONCLUSIONS: The current study demonstrated the oncogenic property of BCL6 in breast cancer and further study could target BCL6 as a novel potential therapeutic strategy for breast cancer.

A sequence variant in the phospholipase C epsilon C2 domain is associated with esophageal carcinoma and esophagitis.

A single-nucleotide polymorphism (rs2274223: A5780G:His1927Arg) in the phospholipase C epsilon gene (PLCϵ) was recently identified as a susceptibility locus for esophageal cancer in Chinese subjects. To determine the underlying mechanisms of PLCϵ and this SNP in esophageal carcinogenesis, we analyzed PLCϵ genotypes, expression, and their correlation in esophageal cancer cell lines, non-transformed esophageal cells, 58 esophageal squamous cell carcinomas and 10,614 non-cancer subjects from China. We found that the G allele (AG or GG) was associated with increased PLCϵ mRNA and protein expression in esophageal cancer tissues and in esophageal cancer cell lines. G allele was also associated with higher enzyme activity, which might be associated with increased protein expression. Quantitative analysis of the C2 domain sequences revealed that A:G allelic imbalance was strongly linked to esophageal malignancy. Moreover, the analysis of 10,614 non-cancer subjects demonstrated that the G allele was strongly associated with moderate to severe esophagitis in the subjects from the high-incidence areas of China (OR 6.03, 95% CI 1.59-22.9 in high-incidence area vs. OR 0.74, 95% CI 0.33-1.64 in low-incidence area; P = 0.008). In conclusion, the PLCϵ gene, particularly the 5780G allele, might play a pivotal role in esophageal carcinogenesis via upregulating PLCϵ mRNA, protein, and enzyme activity, and augmenting inflammatory process in esophageal epithelium. Thus, 5780G allele may constitute a promising biomarker for esophageal squamous cell carcinoma risk stratification, early detection, and progression prediction.

Pretreatment of old-age landfill leachate by microwave-assisted catalytic oxidation in the presence of activated carbon.

Landfill leachate is posing an ever-greater environmental hazard. Recently, a process for purification combining activated carbon, microwave (MW) and Fenton oxidation has drawn much attention. In this study, the effectiveness of this process for the pretreatment of an old-age landfill leachate was tested. The effects of various parameters were investigated and the optimal condition included as follows: MW energy density, 6 W/mL; MW power, 300 W; radiation time, 8 min; H2O2 dosage, 0.1 mol/L; Fe(2+)-EDTA dosage, 0.02 mol/L; granular activated carbon (GAC) dosage, 6 g/L. Within the present experimental condition applied, the chemical oxygen demand (COD) removal reached 56.5%, and the ratio of 5-day biochemical oxygen demand to chemical oxygen demand (BOD5/COD) was enhanced from 0.122 to 0.462. Comparing with GAC, MW and Fenton alone or the combinations of any two of them, MW/Fenton/GAC displayed superior treatment efficiency. The MW/Fenton/GAC process is believed to be a promising pretreatment technology for biorefractory old-age landfill leachate.

[Construction of electrochemiluminescence system for harmful algae detection].

To develop a new technique, Electrochemiluminescence-Molecular Probe (ECL-MP), for harmful algae detection, a highly sensitive electrochemiluminescence (ECL) detection system was set up based on the principle of ECL and related literature. The optimization tests were carried out, including the impact of voltage and current, the concentration of tripropylamine (TPrA) and the pH of phosphate buffer (PBS). The determination limit of Ru (bpy)3Cl2 x 6H2O was 10(-11) mol x L(-1) and the detection range was from 10(-9) - 10(-5) mol x L(-1) as well as the detection amount of substance was in the range from 0.4 pmol-4 nmol in the optimal reaction conditions with voltage of 1.0 V, current of 1.0 mA, TPrA concentration of 1.5 mol x L(-1) and pH of 7.4. It was proved by facts that this ECL analyzer was stable and highly sensitive, which was helpful in establishment of ECL-MP.

Loss of miR-133a expression associated with poor survival of breast cancer and restoration of miR-133a expression inhibited breast cancer cell growth and invasion.

BACKGROUND: miRNAs, endogenous oligonucleotide RNAs, play an important role in mammary gland carcinogenesis and tumor progression. Detection of their expression and investigation of their functions could lead to discovery of novel biomarkers for breast cancer. METHODS: In situ hybridization was used to detect miR-133a expression in formalin-fixed paraffin-embedded breast surgical specimens from 26 benign, 34 pericancerously normal and 90 cancerous tissues. qRT-PCR was performed to assess miR-133a levels in 6 breast cell lines and 10 benign and 18 cancerous fresh breast tissue specimens. Cell viability, migration, and invasion assays were used to determine the role of miR-133a in regulation of breast cancer cell growth, migration, and invasion, respectively. Luciferase assay was performed to assess miR-133a binding to FSCN1 gene. RESULTS: Expression of miR-133a was reduced from normal through benign to cancerous breast tissues. Expression of miR-133a was also low in breast cancer cell lines. The reduced miR-133a expression was associated with lymph nodes metastasis, high clinical stages, and shorter relapse-free survivals of patients with breast cancer. Furthermore, transfection of miR-133a oligonucleotides slightly inhibited growth but significantly decreased migration and invasion capacity of breast cancer cells, compared with negative controls, whereas knockdown of miR-133a expression induced breast cancer cell migration and invasion. In addition, we identified a putative miR-133a binding site in the 3'-untranslated region (UTR) of Fascin1 (FSCN1) gene using an online bioinformatical tool. We found that miR-133a transfection significantly reduced expression of FSCN1 mRNA and protein. The luciferase reporter assay confirmed that FSCN1 was the direct target gene of miR-133a. CONCLUSIONS: miR-133a expression was lost in breast cancer tissues, loss of which was associated with lymph nodes metastasis, high clinical stages and shorter relapse-free survivals of patients with breast cancer. Functionally, miR-133a can suppress tumor cell invasion and migration and targeted the expression of FSCN1. Future study will verify whether detection of miR-133a expression can served as a novel biomarker for breast cancer progression and patient prognosis.

Suppression of esophageal cancer cell growth using curcumin, (-)-epigallocatechin-3-gallate and lovastatin.

AIM: To determine the effects of curcumin, (-)-epigallocatechin-3-gallate (EGCG), lovastatin, and their combinations on inhibition of esophageal cancer. METHODS: Esophageal cancer TE-8 and SKGT-4 cell lines were subjected to cell viability methyl thiazolyl tetrazolium and tumor cell invasion assays in vitro and tumor formation and growth in nude mouse xenografts with or without curcumin, EGCG and lovastatin treatment. Gene expression was detected using immunohistochemistry and Western blotting in tumor cell lines, tumor xenografts and human esophageal cancer tissues, respectively. RESULTS: These drugs individually or in combinations significantly reduced the viability and invasion capacity of esophageal cancer cells in vitro. Molecularly, these three agents reduced the expression of phosphorylated extracellular-signal-regulated kinases (Erk1/2), c-Jun and cyclooxygenase-2 (COX-2), but activated caspase 3 in esophageal cancer cells. The nude mouse xenograft assay showed that EGCG and the combinations of curcumin, EGCG and lovastatin suppressed esophageal cancer cell growth and reduced the expression of Ki67, phosphorylated Erk1/2 and COX-2. The expression of phosphorylated Erk1/2 and COX-2 in esophageal cancer tissue specimens was also analyzed using immunohistochemistry. The data demonstrated that 77 of 156 (49.4%) tumors expressed phosphorylated Erk1/2 and that 121 of 156 (77.6%) esophageal cancers expressed COX-2 protein. In particular, phosphorylated Erk1/2 was expressed in 23 of 50 (46%) cases of esophageal squamous cell carcinoma (SCC) and in 54 of 106 (50.9%) cases of adenocarcinoma, while COX-2 was expressed in 39 of 50 (78%) esophageal SCC and in 82 of 106 (77.4%) esophageal adenocarcinoma. CONCLUSION: The combinations of curcumin, EGCG and lovastatin were able to suppress esophageal cancer cell growth in vitro and in nude mouse xenografts, these drugs also inhibited phosphorylated Erk1/2, c-Jun and COX-2 expression.

miR-340 inhibition of breast cancer cell migration and invasion through targeting of oncoprotein c-Met.

BACKGROUND: Different microRNAs have been shown to have oncogenic and tumor-suppressive functions in human cancers. Detection of their expression may lead to identifying novel markers for breast cancer. METHODS: The authors detected miR-340 expression in 4 human breast cell lines and then focused on its role in regulation of tumor cell growth, migration, and invasion and target gene expression. They then analyzed miR-340 expression in benign and cancerous breast tissue specimens. RESULTS: Endogenous miR-340 expression was down-regulated in the more aggressive breast cancer cell lines, which was confirmed in breast cancer tissue specimens by using quantitative real-time polymerase chain reaction. Further studies showed that induction of miR-340 expression was able to suppress tumor cell migration and invasion, whereas knockdown of miR-340 expression induced breast cancer cell migration and invasion. At the gene level, the authors identified c-Met as a direct miR-340 target to mediate cell migration and invasion through regulation of MMP-2 and MMP-9 expression. Ex vivo, loss of miR-340 expression was associated with lymph node metastasis, high tumor histological grade, clinical stage, and shorter overall survival of breast cancer as well as increased c-Met expression in breast cancer tissue specimens. CONCLUSIONS: miR-340 may play an important role in breast cancer progression, suggesting that miR-340 should be further evaluated as a novel biomarker for breast cancer metastasis and prognosis, and potentially a therapeutic target.

Tumor-suppressor activity of RRIG1 in breast cancer.

BACKGROUND: Retinoid receptor-induced gene-1 (RRIG1) is a novel gene that has been lost in several types of human cancers. The aim of this study was to determine whether RRIG1 plays a role in breast cancer, such as in the suppression of breast cancer cell growth and invasion. METHODS: Immunohistochemistry was used to detect RRIG1 expression in breast tissue specimens. Gene transfection was used to restore or knock down RRIG1 expression in breast cancer cell lines for analysis of cell viability, colony formation, and migration/invasion potential. Reverse-transcription polymerase chain reaction and western blot assays were used to detect the changes in gene expression. The RhoA activation assay was used to assess RRIG1-induced inhibition of RhoA activity. RESULTS: The immunohistochemical data showed that RRIG1 expression was reduced in breast cancer tissues compared with normal and atypical hyperplastic breast tissues. RRIG1 expression was inversely correlated with lymph node metastasis of breast cancer but was not associated with the status of hormone receptors, such as estrogen receptor, progesterone receptor, or HER2. Furthermore, restoration of RRIG1 expression inhibited proliferation, colony formation, migration, and invasion of breast cancer cells. Expression of RRIG1 also reduced phosphorylated Erk1/2 and Akt levels; c-Jun, MMP9, and Akt expressions; and RhoA activity. In contrast, knockdown of RRIG1 expression promoted breast cancer cell proliferation, colony formation, migration, and invasion potential. CONCLUSION: The data from the current study indicated that RRIG1 expression was reduced or lost in breast cancer and that restoration of RRIG1 expression suppressed breast cancer cell growth and invasion capacity. Future studies will determine the underlying molecular mechanisms and define RRIG1 as a tumor-suppressor gene in breast cancer.

Prognostic significance of differentially expressed miRNAs in esophageal cancer.

Altered microRNA (miRNA) expression has been found to promote carcinogenesis, but little is known about the role of miRNAs in esophageal cancer. In this study, we selected 10 miRNAs and analyzed their expression in 10 esophageal cancer cell lines and 158 tissue specimens using Northern blotting and in situ hybridization, respectively. We found that Let-7g, miR-21 and miR-195p were expressed in all 10 cell lines, miR-9 and miR-20a were not expressed in any of the cell lines, and miR-16-2, miR-30e, miR-34a, miR-126 and miR-200a were expressed in some of the cell lines but not others. In addition, transient transfection of miR-34a inhibited c-Met and cyclin D1 expression and esophageal cancer cell proliferation, whereas miR-16-2 suppressed RAR-ß(2) expression and increased tumor cell proliferation. Furthermore, we found that miR-126 expression was associated with tumor cell dedifferentiation and lymph node metastasis, miR-16-2 was associated with lymph node metastasis, and miR-195p was associated with higher pathologic disease stages in patients with esophageal adenocarcinoma. Kaplan-Meier analysis showed that miR-16-2 expression and miR-30e expression were associated with shorter overall and disease-free survival in all esophageal cancer patients. In addition, miR-16-2, miR-30e and miR-200a expression were associated with shorter overall and disease-free survival in patients with esophageal adenocarcinoma; however, miR-16-2, miR-30e and miR-200a expression were not associated with overall or disease-free survival in squamous cell carcinoma patients. Our data indicate that further evaluation of miR-30e and miR-16-2 as prognostic biomarkers is warranted in patients with esophageal adenocarcinoma. In addition, the role of miR-34a in esophageal cancer also warrants further study.

MiR-339-5p inhibits breast cancer cell migration and invasion in vitro and may be a potential biomarker for breast cancer prognosis.

BACKGROUND: MicroRNAs (miRNAs) play an important role in the regulation of cell growth, differentiation, apoptosis, and carcinogenesis. Detection of their expression may lead to identifying novel markers for breast cancer. METHODS: We profiled miRNA expression in three breast cancer cell lines (MCF-7, MDA-MB-231, and MDA-MB-468) and then focused on one miRNA, miR-339-5p, for its role in regulation of tumor cell growth, migration, and invasion and target gene expression. We then analyzed miR-339-5p expression in benign and cancerous breast tissue specimens. RESULTS: A number of miRNAs were differentially expressed in these cancer cell lines. Real-time PCR indicated that miR-339-5p expression was downregulated in the aggressive cell lines MDA-MB-468 and MDA-MB-231 and in breast cancer tissues compared with benign tissues. Transfection of miR-339-5p oligonucleotides reduced cancer cell growth only slightly but significantly decreased tumor cell migration and invasion capacity compared with controls. Real-time PCR analysis showed that BCL-6, a potential target gene of miR-339-5p, was downregulated in MDA-MB-231 cells by miR-339-5p transfection. Furthermore, the reduced miR-339-5p expression was associated with an increase in metastasis to lymph nodes and with high clinical stages. Kaplan-Meier analyses found that the patients with miR-339-5p expression had better overall and relapse-free survivals compared with those without miR-339-5p expression. Cox proportional hazards analyses showed that miR-339-5p expression was an independent prognostic factor for breast cancer patients. CONCLUSIONS: MiR-339-5p may play an important role in breast cancer progression, suggesting that miR-339-5p should be further evaluated as a biomarker for predicting the survival of breast cancer patients.

[Expressions of 6 microRNAs in prostate cancer].

OBJECTIVE: Experimental evidence shows that microRNAs play an important role in the initiation and progression of human malignancies. The present study aimed to investigate the expressions of 6 microRNAs in prostate cancer (PCa) and their clinical significance. METHODS: We investigated the expression profiles of 6 microRNAs (let-7g, let-7d, miR-98, miR-96, miR-182 and miR-183) using the method of locked nucleic acid (LNA)-modified oligonucleotide in situ hybridization (ISH) and the technology of tissue microarray (TMA) with the formalin-fixed paraffin-embedded (FFPE) specimens from 52 patients with PCa and 38 with benign prostatic hyperplasia (BPH). Then we analyzed the correlation among the expressions of the 6 microRNAs in PCa and their correlation with the Gleason score and clinical stages of PCa. RESULTS: Compared with BPH, the PCa patients showed decreased expressions of miR-98, let-7d and let-7g, and decreased expressions of miR-96, miR-182 and miR-183, with statistically significant differences between the two groups (P < 0.05). The positive rate of the 6 microRNAs was significantly correlated with the Gleason grades of PCa (P < 0.05), but not with the age and serum PSA concentration of the patients (P > 0.05). The expressions of miR-96 and miR-182 were correlated with the clinical stages of the tumor (P < 0.05). There was a positive correlation among the expressions of miR-96, miR-182 and miR-183 (P = 0.00, r = 0.41), as well as between the expressions of let-7d and let-7g (P = 0.00, r = 0.46) in the PCa tissues. And the expression of miR-98 was positively correlated with those of let-7d and let-7g (P = 0.00, r = 0.46). CONCLUSION: The expression profiles of the microRNAs let-7d, let-7g, miR-98, miR-96, miR-182 and miR-183 reflect the biological behavior of PCa to some extent, and might be important biomarkers for the early detection and prognostic assessment of prostate cancer.

Benzo[a]pyrene diol epoxide suppresses retinoic acid receptor-beta2 expression by recruiting DNA (cytosine-5-)-methyltransferase 3A.

Tobacco smoke is an important risk factor for various human cancers, including esophageal cancer. How benzo [a]pyrene diol epoxide (BPDE), a carcinogen present in tobacco smoke as well as in environmental pollution, induces esophageal carcinogenesis has yet to be defined. In this study, we investigated the molecular mechanism responsible for BPDE-suppressed expression of retinoic acid receptor-beta2 (RAR-beta2) in esophageal cancer cells. We treated esophageal cancer cells with BPDE before performing methylation-specific polymerase chain reaction (MSP) to find that BPDE induced methylation of the RAR-beta2 gene promoter. We then performed chromatin immunoprecipitation (ChIP) assays to find that BPDE recruited genes of the methylation machinery into the RAR-beta2 gene promoter. We found that BPDE recruited DNA (cytosine-5-)-methyltransferase 3 alpha (DNMT3A), but not beta (DNMT3B), in a time-dependent manner to methylate the RAR-beta2 gene promoter, which we confirmed by reverse transcription-polymerase chain reaction (RT-PCR) analysis of the reduced RAR-beta2 expression in these BPDE-treated esophageal cancer cell lines. However, BPDE did not significantly change DNMT3A expression, but it slightly reduced DNMT3B expression. DNA methylase inhibitor 5-aza-2'-deoxycytidine (5-Aza) and DNMT3A small hairpin RNA (shRNA) vector antagonized the effects of BPDE on RAR-beta2 expressions. Transient transfection of the DNMT3A shRNA vector also antagonized BPDE's effects on expression of RAR-beta2, c-Jun, phosphorylated extracellular signal-regulated protein kinases 1/2 (ERK1/2), and cyclooxygenase-2 (COX-2), suggesting a possible therapeutic effect. The results of this study form the link between the esophageal cancer risk factor BPDE and the reduced RAR-beta2 expression.

Antitumor effect of retinoic acid receptor-beta2 associated with suppression of cyclooxygenase-2.

Retinoic acid receptor-beta2 (RAR-beta2) is a putative tumor suppressor gene in various cancers. To determine the underlying molecular mechanisms, we transfected RAR-beta2 cDNA into esophageal cancer TE-1 and TE-8 cells and found that RAR-beta2 suppressed tumor cell growth in vitro and tumor formation in nude mice in TE-8 cells, whereas the stable transfection of RAR-beta2 did not restore retinoid sensitivity or inhibit tumor formation in nude mouse in TE-1 cells. Molecularly, we revealed that RAR-beta2 antitumor activity was associated with expression and suppression of cyclooxygenase-2 (COX-2) in these tumor cell lines. Moreover, antisense RAR-beta2 cDNA induced COX-2 expression in TE-3 cells. Furthermore, when COX-2 expression is first blocked by using antisense COX-2 expression vector, the effect of RAR-beta2 is diminished in these tumor cells. In addition, we analyzed expression of RAR-beta2 and COX-2 mRNA in tissue specimens and found that RAR-beta2 expression is associated with low levels of COX-2 expression in esophageal cancer tissues. Induction of RAR-beta2 expression in oral leukoplakia tissues after the patients treated with 13-cis RA correlated with a reduction in COX-2 expression and clinical response. Our findings indicate that some of RAR-beta2 antitumor activities are mediated by suppression of COX-2 expression in some of these esophageal cancer cells. After correlating antitumor effect of RAR-beta2 with COX-2 expression in the published studies, we also found the association. Thus, further studies will determine whether manipulation of COX-2 expression in different cancers can antagonize RAR-beta2 activity.

Risk factors and gene expression in esophageal cancer.

Esophageal cancer is a significant worldwide health problem because of its poor prognosis and high incidence in certain parts of the world. Tobacco smoke and alcohol consumption are significant risk factors for esophageal squamous cell carcinoma, whereas frequent gastroesophageal reflux and subsequent inflammatory reactions play a role in causing the adenocarcinoma. Esophageal carcinogenesis involves multiple genetic alterations. A large body of knowledge has been generated regarding molecular alterations associated with esophageal carcinogenesis. These alterations include aberrant cell cycle control, DNA repair, cellular enzymes, growth factor receptors, and nuclear receptors. This chapter reviews the most frequent gene alterations and their correlation with risk factors as well as the prevention strategies in esophageal cancer.

Slit2 inhibits growth and metastasis of fibrosarcoma and squamous cell carcinoma.

Slits are a group of secreted glycoproteins that play a role in the regulation of cell migration. Previous studies suggested that Slit2 might be a tumor-suppressor gene. However, it remained to be determined whether Slit2 suppressed tumor growth and metastasis in animal models. We showed that Slit2 expression was decreased or abolished in human esophageal squamous cell carcinomas (SCCs) compared to normal tissues by in situ hybridization. Stable transfection of human SCC A431 and fibrosarcoma HT1080 cells with Slit2 gene suppressed tumor growth in athymic nude mice. Apoptosis in Slit2-transfected tumors was increased, whereas proliferating cells were decreased, suggesting a mechanism for Slit2-mediated tumor suppression. This was supported by further analysis indicating that antiapoptotic molecules Bcl-2 and Bcl-xl and cell cycle molecules Cdk6 and Cyclin D1 were down-regulated in Slit2-transfected tumors. Furthermore, wound healing and Matrigel invasion assays showed that the transfection with Slit2 inhibited tumor cell migration and invasion. Slit2-transfected tumors showed a high level of keratin 8/18 and a low level of N-cadherin expression compared to empty vector-transfected tumors. More importantly, Slit2 transfection suppressed the metastasis of HT1080 tumor cells in lungs after intravenous inoculation. Collectively, our study has demonstrated that Slit2 inhibits tumor growth and metastasis of fibrosarcoma and SCC and that its effect on cell cycle and apoptosis signal pathways is an important mechanism for Slit2-mediated tumor suppression.

Statin induces apoptosis and cell growth arrest in prostate cancer cells.

Statins are a class of low molecular weight drugs that inhibit the rate-limiting enzyme of the mevalonate pathway 3-hydroxy-3-methylglutaryl-CoA reductase. Statins have been approved and effectively used to control hypercholesterolemia in clinical setting. Recent study showed statin's antitumor activity and suggested a potential role for prevention of human cancers. In this study, we did cell viability, DNA fragmentation, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assays to evaluate the action of statins on prostate cancer cells and used Western blotting and RhoA activation assay to investigate the underlying molecular mechanism of action. Our data showed that lovastatin and simvastatin effectively decreased cell viability in three prostate cancer cell lines (PC3, DU145, and LnCap) by inducing apoptosis and cell growth arrest at G(1) phase. Both lovastatin and simvastatin induced activation of caspase-8, caspase-3, and, to a lesser extent, caspase-9. Both statins suppressed expression of Rb, phosphorylated Rb, cyclin D1, cyclin D3, CDK4, and CDK6, but induced p21 and p27 expression in prostate cancer cells. Furthermore, lovastatin and simvastatin suppressed RhoA activation and c-JUN expression, but not cyclooxygenase-2 expression. Our data showed that the antitumor activity of statins is due to induction of apoptosis and cell growth arrest. The underlying molecular mechanism of statin's action is mediated through inactivation of RhoA, which in turn induces caspase enzymatic activity and/or G(1) cell cycle. Future studies should focus on examining statins and other apoptosis-inducing drugs (e.g., cyclooxygenase-2 inhibitors or curcumin) together to assess their efficacy in prevention of prostate cancer.

Prognostic significance of MMP-9 and TIMP-1 serum and tissue expression in breast cancer.

Tumor progression and metastasis contribute to the great majority of breast cancer deaths. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are thought to be involved in tumor progression and metastasis. Thus, we determined whether the expression of MMP-9 and TIMP-1 is associated with prognosis in breast cancer patients. We measured serum MMP-9 and TIMP-1 by enzyme-linked immunosorbent assay in 60 breast cancer patients, 18 benign breast disease patients and 15 healthy controls. We also evaluated the expression of MMP-9 and TIMP-1 protein and mRNA in paraffin-embedded tumor tissues from the 60 breast cancer patients by immunohistochemistry and in situ hybridization. We then correlated serum and tissue levels of MMP-9 and TIMP-1 in breast cancer samples and their expression with patients' clinicopathologic characteristics. We found that serum levels of MMP-9 and TIMP-1 were significantly higher in breast cancer patients than in benign breast disease and in healthy controls. High serum levels of MMP-9 and TIMP-1 were associated with lymph node metastasis, higher tumor stage and lower relapse-free and overall survival (OS) rates. Compared to low expression, high tissue expression of MMP-9 protein was associated with lymph node metastasis and higher tumor stage; and high tissue expression of TIMP-1 was associated with a lower OS rate. Our findings suggest that MMP-9 and TIMP-1 may further be evaluated as biomarkers for predicting progression and prognosis of breast cancer.

Targeting the activator protein 1 transcription factor for the prevention of estrogen receptor-negative mammary tumors.

The oncogene erbB2 is overexpressed in 20% to 30% human breast cancers and is most commonly overexpressed in estrogen receptor (ER)-negative breast cancers. Transgenic mice expressing erbB2 develop ER-negative mammary tumors, mimicking human breast carcinogenesis. Previously, we have shown that activator protein 1 (AP-1) regulates proliferation of ER-negative breast cancer cells. We hypothesized that blockade of AP-1 in mouse mammary epithelial cells will suppress ER-negative tumorigenesis induced by erbB2. Trigenic erbB2 mice were generated by crossing a bigenic pUHD-Tam67/MMTV-rtTA mouse to a MMTV-erbB2 mouse. The resulting trigenic mice develop tumors and express a doxycycline-inducible c-Jun dominant negative mutant (Tam67) in the mammary glands. In vivo AP-1 blockade by Tam67 expression started delayed mammary tumor formation in MMTV-erbB2 mice by more than 11 weeks. By 52 weeks of age, 100% (18 of 18) of the untreated animals had developed mammary tumors, whereas 56% (9 of 16) of the doxycycline-treated trigenic mice developed tumors. In addition, the tumors that arose in the AP-1-blocked erbB2 mice failed to express Tam67. Twenty-five percent of the doxycycline-treated MMTV-erbB2 mice survived more than 72 weeks of age without developing mammary tumors. Examination of normal-appearing mammary glands from these mice showed that AP-1 blockade by Tam67 also significantly prevents the development of premalignant lesions in these glands. The expression of erbB2 either in normal mammary tissue or in mammary tumors was not altered. Our results show that blocking the AP-1 signaling in mammary cells suppresses erbB2-induced transformation, and show that the AP-1 transcription factor is a critical transducer of erbB2. These results provide a scientific rationale to develop targeted drugs that inhibit AP-1 to prevent the development of ER-negative breast cancer.