Involvement of CYR61 and CTGF in the fascin-mediated proliferation and invasiveness of esophageal squamous cell carcinomas cells.

Fascin is overexpressed in esophageal squamous cell [corrected] carcinoma (ESCC) and involved in the proliferation and invasiveness of ESCC cells. In this study, we retrospectively examined the expression of fascin in ESCC samples by immunohistochemistry and revealed that overexpression of fascin was related to poor patient survival. RNAi-mediated knockdown of fascin in ESCC cells significantly inhibited cell proliferation and invasiveness, whereas forced expression of fascin in immortalized esophageal epithelial cells accelerated cell proliferation and invasiveness. To explore the underlying mechanism, cDNA microarray was performed to identify the differential gene expression profiles between a fascin-depleted cell line by RNAi and the corresponding control ESCC cells. Results showed that 296 genes were differentially expressed on fascin depletion. In this study, we focused on two down-regulated genes: CYR61 and CTGF. We found that restored expression of either CYR61 or CTGF led to a recovery of the suppression of cellular proliferation and invasiveness induced by down-regulation of fascin expression; the protein level of CYR61 and CTGF were up-regulated in ESCCs and their expression pattern correlated with fascin overexpression. Finally, analysis of signal transduction revealed that fascin affected the expressions of CYR61 and CTGF through transforming growth factor (TGF)-beta pathway. Taken together, we propose that fascin regulates the proliferation and invasiveness of ESCC cells by modulating the expression of CTGF and CYR61 via TGF-beta pathway.

NGAL and NGALR are frequently overexpressed in human gliomas and are associated with clinical prognosis.

Recently, neutrophil gelatinase-associated lipocalin (NGAL) and its cell surface receptor, NGALR, have been shown to have critical roles in the biology of various tumors. Therefore, we investigated the expression of NGAL and NGALR in tumor sections obtained from patients with gliomas, and compared these results with the clinical characteristics of the patients. Using immunohistochemical assays, the expression levels of NGAL and NGALR were found to be up-regulated in tumor tissues, and to be related to tumor grade (p < 0.001). A positive correlation between expression of the two markers was also observed in these assays (r = 0.849; p < 0.001). Overexpression of NGAL and NGALR in glioma tissues was also confirmed in western blot analysis and real-time quantitative RT-PCR assays. Furthermore, overexpression of NGAL and NGALR was found to be significantly associated with poor prognosis (p < 0.001 in each case). Multivariate analysis identified patient age, tumor grade, and expression levels of NGAL and NGALR to be independent prognostic factors. In particular, NGAL(2+)/NGALR(2+) tissues were associated with lower rates of survival (risk ratio, 1.378; 95% CI, 1.102-1.724; p = 0.005). These findings suggest that NGAL and NGALR expression are frequently up-regulated in gliomas, and are closely associated with poor clinical outcome.

Specificity protein 1 regulates fascin expression in esophageal squamous cell carcinoma as the result of the epidermal growth factor/extracellular signal-regulated kinase signaling pathway activation.

The overexpression of fascin in human carcinomas is associated with aggressive clinical phenotypes and poor prognosis. However, the molecular mechanism underlying the increased expression of fascin in cancer cells is largely unknown. Here, we identified a Sp1 binding element located at -70 to -60 nts of the FSCN1 promoter and validated that Sp1 specifically bound to this element in esophageal carcinoma cells. Fascin expression was enhanced by Sp1 overexpression and blocked by Sp1 RNAi knockdown. Specific inhibition of ERK1/2 decreased phosphorylation levels of Sp1, and thus suppressed the transcription of the FSCN1, resulting in the down-regulation of fascin. Stimulation with EGF could enhance fascin expression via activating the ERK1/2 pathway and increasing phosphorylation levels of Sp1. These data suggest that FSCN1 transcription may be subjected to the regulation of the EGF/EGFR signaling pathway and can be used as a viable biomarker to predict the efficacy of EGFR inhibitors in cancer therapies.

Bronchogenic and alveologenic tumors in mice induced by N-nitrosopiperidine.

The aim of this study was to explore the histogenesis and carcinogenesis of pulmonary cancer induced by N-nitrosopiperidine (NPIP) in mice. NPIP is a form of N-nitrosamine found in tobacco smoke, which has been shown to be a genotoxic chemical as well as a mutagenic compound for inducing chromosome aberrations and severe clastogenicity. In this study, 80 BALB/C strain mice were injected with 0.2 mmol/kg NPIP intraperitoneally for 8 weeks, and experiments were conducted for a further 16 weeks. For the control group, 40 mice were injected with an equal volume of 0.9% NaCl. Pulmonary tissues and tumors in the NPIP-treated group were examined by light microscopy and transmission electron microscopy and compared with the control group at 4-week intervals. The mRNA levels of p53 (mutant), bcl-2, c-myc, ras, and subunits of telomerase - telomerase reverse transcriptase (TERT) and an RNA component, TR - were assayed by mPCR or RT-PCR. Twenty-two mice in the experimental group were found to develop pulmonary tumors, but none in the control group. All tumors found in the experimental group originated from alveolar type II epithelial cells. In addition, 6 of the 22 mice also developed tumors of bronchogenic origin. The expression of p53, bcl-2, c-myc, ras, and the subunits of telomerase were found to increase in all pulmonary tissues and tumors formed thereafter upon NPIP treatment. In summary, NPIP-induced mouse lung tumors exhibited morphological changes during carcinogenesis, which may be the consequence of overexpression of some genes associated with the development of carcinoma and changes in subunits of telomerase. This mouse model of lung tumor formation may be a useful tool to delineate the histogenesis and carcinogenesis of human pulmonary cancer.

The expression of CFL1 and N-WASP in esophageal squamous cell carcinoma and its correlation with clinicopathological features.

Cofilin1 (CFL1) is an actin-modulating protein, which belongs to the ADF/Cofilin family. Neural Wiskott-Aldrich syndrome protein (N-WASP) is the key regulator of the actin cytoskeleton, a member of Wiskott-Aldrich syndrome protein family. They have been suggested to be involved in cancer cell invasion and metastasis. In this study, the expression patterns of CFL1 and N-WASP in normal esophageal mucosa and esophageal squamous cell carcinoma (ESCC) and their correlation with clinical characteristics were investigated. Immunohistochemical staining showed that CFL1 was expressed in nuclear and cytoplasm of cancer cells. However, N-WASP was mainly found in the cytoplasm of the cancer cells. There were significant evidences that proved that CFL1 is correlated with clinicopathological factors in ESCC, such as infiltration depth, lymph node metastasis and pathological staging (P < 0.05). It is also proved that N-WASP is related to lymph node metastasis and pathological staging in ESCC (P < 0.05). Kaplan-Meier analysis showed that there was no correlation between CFL1 and N-WASP protein expression and survival (P > 0.05). Moreover, the mRNA expression of CFL1 and N-WASP was detected by quantitative real time PCR in 70 tissue specimens. The results showed that CFL1 mRNA level was over-expressed in ESCC tissue (P < 0.05), while N-WASP mRNA expression level was not different between cancerous tissues and adjacent normal esophageal mucosa (P > 0.05). Also, CFL1 mRNA expression was significantly associated with regional lymph node metastasis and pathological staging (P < 0.05). Kaplan-Meier analysis showed that there was no correlation between CFL1 and N-WASP mRNA expression and survival (P > 0.05). Our findings suggested that CFL1 and N-WASP may play an important role in the tumorigenesis of ESCC, and to be the candidate novel biomarkers for the diagnosis and prognosis of ESCC. These findings may have implications for targeted therapies in patients with ESCC.

Prognostic significance of perigastric lymph nodes metastases on survival in patients with thoracic esophageal cancer.

Several publications have showed that the number of metastatic lymph node (LN) should be taken into consideration in nodal category of esophageal cancer, but seldom considered extent of involved regional LNs. The aim of this study is to evaluate the significance of the extent of regional LN metastasis on survival in patients with esophageal cancer. A total of 245 thoracic esophageal cancer patients underwent transthoracic esophagectomy with standard lymphadenectomy between January 2000 and December 2006 were included in the study. Data including demographic factors, pathologic findings, LN parameters and survival outcomes were collected. The survival experience was depicted using Kaplan-Meier method. A multivariate Cox proportional hazard model was used to screen the significant prognostic factors. The univariate analysis to further explore the significant prognostic factor was done by log-rank test. After a median follow-up of 53.2 months, the 5-year survival rate was 46.3% for the entire cohort. Cox model regression indicated that the LN status and perigastric nodal status, aside from residual tumor status, histological tumor type and depth of invasion, were the independent prognostic factors. Patients without LN metastasis had better 5-year survival than those with positive nodes (64.2% vs. 18.9%, X2=35.875, P<0.001). However, For those patients with nodal involvement, there was no difference in 5-year survival between patients with involved nodes<3 and >or=3 (27.8% vs. 0%, X2=0.925, P=0.336). When considering the location of LN metastasis, patients could be further stratified according to whether the perigastric nodes were involved or not (37.5% vs. 10.0%, X2=4.295, P=0.038). In conclusion, involved LN number had no prognostic implication in nodal involved patients based on our data. Whereas, perigastric nodal involvement should be used to refine the N category (N0, no nodal metastasis, N1, non-perigastric node metastasis, N2, perigastric node metastasis) for the future esophageal cancer staging criteria.

Roles of ezrin in the growth and invasiveness of esophageal squamous carcinoma cells.

Ezrin, which crosslinks the cytoskeleton and plasma membrane, is involved in the growth and metastatic potential of cancer cells. Ezrin expression in esophageal squamous cell carcinoma (ESCC) was described recently, but its roles and the underlying mechanism(s) remain unclear. In our study, we first showed that ezrin in ESCC cell is expressed in the nucleus as well as in the cytoplasm and plasma membrane. Then, by using RNAi, we revealed that interference of ezrin expression suppressed the growth, adhesion and invasiveness of ESCC cells. Tumorigenesis experiments revealed that ezrin may directly regulate tumor formation in vivo. To explore the molecular mechanisms through which ezrin contributes to the proliferation and invasiveness of ESCC cells, we used cDNA microarrays to analyze ezrin knockdown cells and the control cells; of 39,000 genes examined, 297 were differentially expressed upon ezrin knockdown, including some proliferation- and invasiveness-related genes such as ATF3, CTGF and CYR61. Furthermore, pathway analysis showed that ezrin knockdown led to decreased activation of the TGF-beta and MAPK pathways, and ezrin-mediated cell invasiveness alteration was dependent on the activation of these pathways. Finally, immunohistochemical staining on 80 ESCC specimens and 50 normal esophageal mucosae revealed that the expression levels of 3 altered genes involved in the regulation of cell proliferation and tumor metastasis, including CTGF, CYR61 and ATF3, were altered in ESCCs, and their expression pattern correlated with ezrin expression. Taken together, we propose that ezrin might function in the growth and invasiveness of ESCC cells through the MAPK and TGF-beta pathways.

Expression and prognostic significance of THBS1, Cyr61 and CTGF in esophageal squamous cell carcinoma.

BACKGROUND: Thrombospondin1 (THBS1), cystene-rich protein 61 (Cyr61) and connective tissue growth factor (CTGF) are all involved in the transforming growth factor-beta (TGF-beta) signal pathway, which plays an important role in the tumorigenesis. The purpose of this study is to explore the expression and prognostic significance of these proteins in esophageal squamous cell carcinoma (ESCC). METHODS: We used immunohistochemistry and western blotting to examine the expression status of THBS1, Cyr61 and CTGF in ESCC. Correlations of THBS1, Cyr61 and CTGF over-expressions with various clinicopathologic factors were also determined by using the Chi-square test or Fisher's exact probability test. Survival analysis was assessed by the Kaplan-Meier analysis and the log-rank test. Relative risk was evaluated by the multivariate Cox proportional hazards model. RESULTS: THBS1, Cyr61 and CTGF were all over-expressed in ESCC. THBS1 over-expression was significantly associated with TNM stage (P = 0.029) and regional lymph node involvement (P = 0.026). Kaplan-Meier survival analysis showed that over-expression of THBS1, Cyr61 or CTGF was related to poor survival of ESCC patients (P = 0.042, P = 0.020, P = 0.018, respectively). Multivariate Cox analysis demonstrated that Cyr61 and CTGF were independent factors in prognosis of ESCC. CONCLUSION: Cyr61, CTGF and THBS1 were all over-expressed in ESCC and might be new molecular markers to predict the prognosis of ESCC patients.

NGALR is overexpressed and regulated by hypomethylation in esophageal squamous cell carcinoma.

PURPOSE: Neutrophil gelatinase-associated lipocalin receptor (NGALR) mRNA level is reduced in isolated chronic myelogenous leukemia blasts but up-regulated in esophageal squamous cell carcinoma (ESCC). The mechanism of NGALR regulation is unknown. Here, we show the expression pattern of NGALR and examine the aberrant methylation of its gene in ESCC and esophageal carcinoma cell lines. EXPERIMENTAL DESIGN: The expression pattern of NGALR was analyzed by immunohistochemistry in 59 ESCCs and compared with noncancerous tissues. The DNA methylation status was investigated by methylation-specific PCR and by bisulfite genomic sequencing in esophageal carcinoma cell lines and surgically resected samples. Methylated cell lines were treated with a methylation inhibitor to restore NGALR expression. RESULTS: The expression of NGALR in ESCC was significantly higher in tumor cell membrane and cytoplasm than in normal esophageal epithelium (P < 0.01). Methylated alleles were detected in three NGALR-nonexpressing cell lines but were not detected in three NGALR-expressing cell lines. Treatment of methylated cell lines with 5-aza-2'-deoxycytidine, a methylation inhibitor, restored NGALR expression. In surgically resected samples, 31 of 77 (40.3%) primary esophageal carcinomas and 46 of 77 (59.7%) paired normal tissues contained methylated NGALR alleles (P < 0.05). CONCLUSIONS: Our results suggest that NGALR hypomethylation contributes to its expression in esophageal carcinomas and that this overexpression may play a role in the pathogenesis of esophageal carcinomas.

Autophagy and endocytosis in the amnion.

To search for the origin of nutrition in the amnion, we focused attention on both endocytotic and autophagic pathways. Using ultrastructural and biochemical methods, we examined 20 human amnions at term gestation. The uptake of horseradish peroxidase (HRP) was used for the detection of endocytosis. Transfection of the LC3-GFP plasmid and staining with monodansylcadaverine (MDC) and LysoTracker red (LTR) were used to demonstrate the formation of autophagic vacuoles. In addition, two autophagic genes, beclin 1 and Atg5, were assayed by RT-PCR. Within the amniotic epithelial (AE) cells, autophagic vacuoles contained organelles and cytoplasmic components and were enclosed by a double membrane. They contained autophagosomes with transfected LC3-GFP that stained positive for MDC and autolysosomes that stained positive for LTR. Endocytosis was an extremely active process in the cellular uptake of fluid and fluid contents and led to formation of vesicles and endosomes, which were found to be positive by HRP test. Many uniform vesicles were collected in the multivesicular bodies (MVBs). Finally, both endosomes and autophagosomes were fused and degraded by lysosomes. The data also demonstrated that large autophagosomes engulfed some endosomes or MVBs. Transcription of beclin 1 and Atg5 occurred in the amnion at term gestation. Taken together, these results show that AE cells have active endocytotic and autophagic capacities and that lysosomes are involved in the intracellular degradation of endosomes and autophagosomes. Sometimes the autophagic and endocytotic pathways converge. This study suggests that of endocytosis and autophagy activities in AE cells can be induced by nutrient limitation and are probably also evoked in response to some hormones in the amniotic fluid. Activation of both endocytotic and autophagic pathways plays different roles in the ability of the cell to acquire nutrients needed for its survival.

Fascin expression in human embryonic, fetal, and normal adult tissue.

This study investigates the distribution of fascin in human embryonic, fetal, and normal adult tissues. Tissue microarray technology was used to perform immunohistochemical experiments on human embryos and fetuses at 4-22 weeks of gestation and adult specimens. Fascin was widely expressed in the nervous system. At 4 weeks of gestation, fascin was present in the neural tube. At 8-12 weeks of gestation, homogenous gene expression was seen in cells of the cerebellum and gastrointestinal tract. In later developmental stages and in adults, Purkinje cells of the cerebellum and glandular epithelium of the gastrointestinal tract showed no expression. Fascin was expressed in the cortex and medulla of the adrenal gland at 8-12 weeks of gestation, whereas immunoreactivity decreased from the zona glomerulosa through the zona reticularis and was essentially negative in the adrenal medulla of adults. Significant expression of fascin was seen throughout development in neurons, follicular dendritic cells of lymphoid tissue, basal layer cells of stratified squamous epithelia, mesenchyme, and vascular endothelial cells. Simple columnar epithelia of the biliary duct, colon, ovary, pancreas, and stomach were all negative for fascin expression. These results show that expression of fascin is time specific and highly tissue specific. Parallels between fascin expression in embryogenesis and carcinogenesis are discussed.

Expression of fascin in thyroid neoplasms: a novel diagnostic marker.

PURPOSE: Fascin, an actin-bundling protein, is markedly upregulated in several epithelial tumors and its expression often correlates with high-grade, extensive invasion, and distant metastasis. However, reports about fascin expression in endocrine tumors remain rare. The aim of the present study was to assess the diagnostic significance of fascin in thyroid neoplasms. METHODS: Thyroid samples from 177 cases were examined for fascin and Ki-67 expression by immunohistochemistry. RESULTS: Fascin immunoreactivity was negative in normal follicles and nodular goiter. Fascin immunostaining was positive in 62.1% (41/66) of thyroid carcinomas and 26.4% (19/72) of thyroid adenomas; the difference being significant (P < 0.0001). In thyroid papillary carcinoma, upregulation of fascin was associated with both the Ki-67 labeling index and the occurrence of lymph node metastasis. CONCLUSION: Fascin may be a novel marker to distinguish thyroid carcinoma from benign lesions and may be involved in the proliferation and metastasis of papillary carcinoma.

A novel alternative spliced variant of neutrophil gelatinase-associated lipocalin receptor in oesophageal carcinoma cells.

Recent studies suggest that NGAL (neutrophil gelatinase-associated lipocalin) is a novel iron transporter with functions distinct from that of transferrin and mediates a new iron-delivery pathway. To get a better understanding of NGAL function in oesophageal carcinoma, we analysed the expression of NGAL receptors in oesophageal carcinoma cells and identified a novel spliced variant designated NgalR-3. When expressed in a heterologous system, the protein produced from this novel spliced variant exhibits the biochemical characteristics of interaction and co-localization with NGAL protein in vivo. This new finding suggests that NgalR-3 may act as a potential NGAL receptor and play a role in NGAL-mediated iron transport in oesophageal carcinoma.

[Inhibitory effect of Oridonin injection on heterotransplanted gastric adenocarcinoma in nude mice and its mechanism].

OBJECTIVE: To investigate the inhibitory effect of Oridonin injection on heterotransplanted tumors of human gastric adenocarcinoma cell line BGC823 cells in nude mice and explore its mechanism. METHODS: Heterotransplanted models of human gastric adenocarcinoma cell line BGC823 cells in nude mice were established. They were divided at random into three groups as control group, low-dose group and high-dose group. The Oridonin solution at concentration of 37.5 mg x kg(-1 x d(-1) and 75 mg x kg(-1) x d(-1) were injected to the mice in low-dose group and high-dose group, respectively, and 0.9% sodium chloride was injected to the mice of control group per day for 10 days sequentially. The mice of the three groups were sacrificed at 11th day after the first injection of Oridonin. The tumor weight of the sacrificed mice was measured. Morphological and ultrastructural examinations of the tumors were carried out by light and electron microscopy. The expression of bcl-2, Bax, Fas and FasL was detected by immunohistochemistry. RESULTS: Oridonin injection showed a suppressive effect on the growth of heterotransplanted tumors in the nude mice. The tumor growth inhibition rates were 48.5% and 70.7% in the low-dose and high-dose groups, respectively. The morphological study demonstrated that tumor cells displayed a typical appearance of apoptosis. The expression of bcl-2 was down-regulated, while Bax, Fas and FasL were up-regulated. CONCLUSION: Oridonin can markedly inhibit the growth of heterotransplanted human gastric adenocarcinoma in nude mice. It was due, at least in part, to the induction of apoptosis in cancer cells.

[Expression and significance of heat shock proteins in esophageal squamous cell carcinoma].

OBJECTIVE: To investigate the expression and significance of HSP27, HSP60, HSP70 and HSP90 alpha in esophageal squamous cell carcinoma (ESCC) and tissues along the incision margin (TIM). METHODS: The presence and the level of expression of HSP27, HSP60, HSP70 and HSP90 alpha were determined in 168 specimens from ESCC and 42 from tissues along TIM by EnVision immunohistochemistry and Western blotting, to compare their positive staining rates and explore the correlation between their expressions and clinicopathologic features in ESCC. RESULTS: The positive staining rates of HSP27, HSP60, HSP70 and HSP90 alpha in ESCC and TIM were 62.0% and 42.1%, 92.7% and 63.2%, 57.9% and 22.2%, and 33.7% and 18.5%, respectively. There was very significant difference between the expression of HSP60 and HSP70 in ESCC and TIM (P < 0.01), but not significant about HSP27 and HSP90 alpha (P > 0.05). The positive staining rate of HSP27 declined with the lower grade of differentiation of ESCC (P < 0.05). CONCLUSION: The present findings suggest that the expression of HSPs of different molecular weight in ESCC and TIM is a common event. The level of expressions of HSP60 and HSP70 are higher than those in TIM. HSP60 and HSP70 expression correlated with the biological behavior of ESCC. The expression of HSP27 was positively correlated to the grade of differentiation of ESCC. Overexpression of HSP27 may be associated to the differentiation of squamous cell carcinoma.

The inhibition of growth and angiogenesis in heterotransplanted esophageal carcinoma via intratumoral injection of arsenic trioxide.

To investigate the antitumor action of arsenic trioxide (As2O3) by intratumoral injection into solid tumors, tumor growth inhibition (TGI) and angiogenesis of heterotransplanted esophageal carcinoma in mice was carried out. The cultured human esophageal carcinoma cells were inoculated into both laterals of the abdominal wall of severe combined immunodeficient (SCID) mice. When both lateral tumors had grown to about 10x8x5 mm(3), the right tumors were treated with an intratumoral injection of As2O3 in dosage of 1, 5 and 10 microg per day, respectively, for 10 days sequentially. Left tumors were treated with PBS (phosphate buffer solution) as control. The weight of transplanted tumor masses were measured and counted for TGI. The tissue of tumor, liver, kidney, heart, lung and brain was examined histopathologically and tumor tissues were examined by light- or electron-microscope. Ki-67 and CD34 were assessed by immunohistochemistry and positive nuclei of Ki-67 and microvessel density (MVD) labeled by CD34 were measured. The results revealed that on the 20th day after the first injection, As2O3-treated tumors were suppressed markedly as compared with the contrarily situated tumor, accompanied by a marked apoptosis and necrosis in tumor cells. The tissue of liver, kidney, heart, lung and brain was unaffected by As2O3. MVD in tumor tissue was decreased in the right side tumor with the significant difference in the 5 micro g and 10 micro g group (p<0.01). TGI was 5.80 (p>0.05), 58.66 (p<0.01) and 73.97% (p<0.01) in the 1, 5 and 10 micro g groups respectively, but 2.21% (p>0.05) in the control group. Conclusively, a repeated administration of As2O3 (5 and 10 microg x 10) induced an increase of tumor growth inhibition and decrease of angiogenesis in the solid tumor in tumor progressive periods. These results suggest that intra-tumoral injection of As2O3 may be investigated as a modality to treat some solid tumors.

E6/E7 genes of human papilloma virus type 18 induced immortalization of human fetal esophageal epithelium.

To study the role played by human papilloma virus (HPV) in carcinogenesis, immortalized esophageal epithelial cells were induced by E6 and E7 genes of HPV type 18 and the biological behavior was studied. Human fetal esophageal epithelial cells were transfected with recombined HPV18E6E7AAV and were cultured and passaged in medium M199. In both the 10th passage (SHEE10) and the 31st passage (SHEE31), their proliferative rates by flow cytometry and their abilities to grow and form colonies in soft agar, or to form tumors in SCID mice were examined. The HPV18 genes of E6E7 and its expression were determined using PCR methods. Cellular telomerase activity was detected by TRAP and chromosomes were analyzed by standard method. Immortalized cell lines of esophageal epithelium induced by the HPV18E6E7 were successfully established and cultured for >100 passages over 4 years. The result of PCR showed that the E6E7 gene of HPV18 was detectable in both cell clones. Both of them were unable to grow in soft-agarose medium and failed to produce tumors in SCID mice. Flow cytometry demonstrated an average of 43% proliferation index in SHEE31, but 28% in SHEE10. Telomerase activity was clearly identified in SHEE31 but not in SHEE10. Cytogenetic analysis demonstrated progression of chromosomal abnormalities with increasing trisome. Our data indicated that genes E6/E7 of the HPV18 were capable of inducing immortalization in fetal esophageal epithelial cells. The immortal phenotype requires both activation of telomerase and genetic alterations that abrogate normal differentiation and promote cellular proliferation. This cell line can assist us to characterize the role played by HPV in carcinogenesis.

Intratumoral injection of arsenic to enhance antitumor efficacy in human esophageal carcinoma cell xenografts.

To enhance the therapeutic efficacy of anticancer agents and to reduce systemic side effects, it was decided to study the effect of arsenic trioxide directly on solid tumors to observe the anticancer effect of arsenic on tumors and the distribution of arsenic in tumors and other organs. Esophageal carcinoma cells were heterotransplanted in severe combined immunodeficient (SCID) mice in both laterals of the abdominal wall. When both lateral tumors had grown to approximately 10x8x5 mm3, tumor-bearing mice were used for 2 experiments. The right tumors were treated with intratumoral injection of As2O3 in 1, 5 and 10 micro g per day for 10 days sequent. The left tumors were treated with phosphate buffer solution as controls. To explore the distribution of As2O3 remaining in tumor and some organs, a single intratumoral injection of As2O3 was studied with quantitative measurement of arsenic by means of atomic absorption spectrometry. The results revealed that on the 17th day after the 1st injection As2O3-treated tumors were suppressed markedly compared to that of the contrarily lateral tumor accompanied by marked apoptosis and necrosis in tumor cells. The tumor growth inhibition (TGI) was 13.56, 62.37 and 76.92% in 1, 5 and 10 micro g group, respectively. There were no pathological changes in heart, lung, spleen, liver, kidney or brain after arsenic administration. Distribution of As2O3 revealed that As2O3 remained at higher concentration in arsenic-treated tumor tissue than in other organs. Our data suggest that intratumoral delivery of As2O3 efficiently suppresses growth of transplanted esophageal carcinoma without systemic side effects. The protocol of As2O3 intratumoral injection will be its potential clinical utility for therapy of solid tumors.

The multistage process of carcinogenesis in human esophageal epithelial cells induced by human papillomavirus.

To investigate the multistage process of carcinogenesis, the progressive alteration of the morphology, telomerase, cytogenesis, oncogenes and tumorigenicity in the process of immortalization and malignant transformation of the human fetal esophageal epithelial cell (SHEE) was studied. The SHEE cells were immortalized by gene E6E7 of human papilloma virus (HPV) type 18 in our laboratory and continually cultivated over 100 passages, which had been malignantly transformed. Cells at the 11th, 35th, 65th and 100th passage were examined according to the following criteria: morphological changes of cell growth, contact-inhibition and anchorage-independent growth (AIG); the cell proliferative and apoptotic index; the modal number of chromosomes; c-myc, p53, bcl-2, ras; telomere length and activities of telomerase and tumorigenicity in nude mice or severe combined immunodeficient (SCID) mice. The cells of the 11th passage were well differentiated and the cells of 100th passage were relatively poorly differentiated with polymorphism, while the cells of 35th and 65th had two distinct differentiations. The proliferative indexes were 21.1%, 32.5%, 33.2%, and 40.9% and the apoptotic indexes were 3.3%, 2.7%, 3.5%, 2.7% in the 11th, 35th, 65th and 100th passage respectively. Karyotypes of four cell passages belonged to hyperdiploidy and hypotriploidy. C-myc, ras, p53 genes were low in the 10th and 35th, and high in the 65th and 100th passage, but bcl-2 was low in 4 passages. Telomere length sharply decreased from normal fetal esophagus cells until the 35th passage, but it was stably expressed in the 65th and 100th passage. The activities of telomerase were expressed in cells of the 35th, 65th and 100th passages. The efficiency of AIG varied in different passages of the SHEE cell and was absent in the 11th passage, low efficiency in the 35th passage and 65th passage, and high efficiency in the 100th passage. Transplanted cells of the 65th and 100th passage into SCID mice resulted in tumor formation, but only the 100th passage cells could grow in nude mice. All of these characteristic changes were in dynamic progressive process. These data demonstrate that carcinogenesis of esophageal epithelial cells induced by HPV is the multistage process, which goes through the initial, immortal, premalignant and malignant transformation stages. The generation of esophageal carcinoma is caused by the accumulation of cellular, genetic and molecular changes.

Mitochondria, calcium and nitric oxide in the apoptotic pathway of esophageal carcinoma cells induced by As2O3.

In order to explore the early apoptotic signal messengers and to search the apoptotic pathway, the morphological and functional changes of mitochondria were examined, and nitric oxide (NO) and calcium ions (Ca2+) were measured in the course of apoptosis in esophageal carcinoma cells induced by As2O3. The esophageal carcinoma cell line SHEEC1, established by HPV in synergy with TPA in our laboratory, were cultured with serum-free medium in a culture flask, 24-well plate and small culture chambers, and added with As2O3 at 1, 3, 5 micromol/l. After 0, 2, 4, 8, 12, 24 h of drug adding the NO were measured from extracellular cultured medium and the SHEEC1 cells were collected from flasks for electron microscopic examination. Fluorescent intensity (FI) of rhodamine 123 (Rho123) labeled cells was detected using laser confocal scanning microscope (LCSM) for evaluation of mitochondrial membrane potential. Intracellular Ca2+ of cells in small culture chambers labeled with Fluo-3 dye were measured using LCSM over time. After adding As2O3, SHEEC1 cells revealed characteristic morphological and functional changes of mitochondria such as hyperplasia, swelling and disruption, accompanying decrease of transmembrane potential (FI of Rho123 decreased). The Ca2+ level increased at once after adding As2O3 and the NO concentration increased step by step till 24 h, then apoptotic morphology of cells occurred. The results suggest that by inducement of As2O3 increasing Ca2+ and NO, the apoptotic signal messengers, will initiate the mitochondria-dependent apoptotic pathway.