High-risk human papillomavirus infection associated with telomere elongation in patients with esophageal squamous cell carcinoma with poor prognosis.

BACKGROUND: Telomere maintenance is crucial in carcinogenesis and tumor progression. The results of a previous study from the authors indicated that infection with high-risk human papillomavirus (HR-HPV) types 16, 18, and 58 was a risk factor for esophageal squamous cell carcinoma (ESCC) in the Shantou region of China. In the current study, the authors explored the association between HR-HPV infection, telomere length (TL), and DNA methylation and their significance in the prognosis of patients with ESCC. METHODS: TL and DNA methylation were analyzed by real-time polymerase chain reaction and methylation-specific polymerase chain reaction in 70 cases of ESCC tumor (T) and paired nontumor (NT) tissues and 50 cases of normal esophagus (NE). The prognostic value of TL and DNA methylation in ESCC was analyzed. RESULTS: TL gradually decreased from NE to NT to T tissue. TL in tumor tissue (T-TL) was found to be longer in tissue that was positive for HR-HPV compared with negative tissue and was found to be positively associated with viral load (Spearman correlation, 0.410; P = .037) and integration (represented by the ratio of HR-HPV E2 to E6/E7 genes; P = .01). The DNA methylation ratio of human telomerase reverse transcriptase was more prevalent with long (≥ 0.7) compared with short (< 0.7) T-TL and was positively correlated with T-TL (Spearman correlation, 0.318; P = .007) and HR-HPV integration (P = .036). Furthermore, Cox proportional hazards modeling revealed a high ratio of T-TL to NT-TL (≥ 0.80) as a factor of poor prognosis, independent of other clinicopathologic variables. CONCLUSIONS: HR-HPV infection and integration related to telomere elongation and DNA methylation of human telomerase reverse transcriptase may be a potential biomarker of prognosis in patients with ESCC.

Lymphangiogenesis and prognostic significance of vascular endothelial growth factor C in gastro-oesophageal junction adenocarcinoma.

Vascular endothelial growth factor C (VEGF-C) is a crucial regulator of the development of lymphatic vessels and is involved in the lymph node metastasis of cancer. The levels of VEGF-C expression and lymphatic vessel density (LVD) in 128 gastro-oesophageal junction adenocarcinoma (GEJA) tissues were examined by immunohistochemistry and analysed for their association with clinicopathological features and disease-free survival. We found that 75.0% of tumour samples displayed strong immunoreactivity to VEGF-C. The levels of VEGF-C expression in the tumour tissues were associated with the stages of the clinical tumours and the lymph node metastasis status, but not with the age, gender and the size and type of tumours in the cohort. Similarly, LVD, as evaluated by anti-D2-40 staining, was also associated with the clinical stages of GEJA. The values of LVD were positively correlated with the levels of VEGF-C expression in these samples (r = 0.3760, P = 0.0001). High levels of VEGF-C expression and high values of LVD were associated with shorter periods of disease-free survival (DFS) in patients with GEJA (P < 0.001). In addition, GEJA at N1 and N2 stages, at T4 stage, chemotherapy after surgery, high levels of VEGF-C expression and lower marginal resection were independent factors for the prognosis of DFS in patients with GEJA. Our data indicate that VEGF-C may promote the lymphangiogenesis and lymphatic metastasis of GEJA and that VEGF-C may be a valuable biomarker for the diagnosis of lymphatic metastasis and a prognostic factor of the survival of patients with GEJA.

[Inhibitory effects of zoledronic acid on cell proliferation and invasion in human nasopharyngeal carcinoma cell line HNE1].

OBJECTIVE: To explore the in vitro anti-tumor effects of zoledronic acid on cell proliferation and invasion in human nasopharyngeal carcinoma cell line HNE1. METHODS: The cytotoxic effects of zoledronic acid on HNE1 cells were detected by MTT assay, invasion of HNE1 cells by Transwell assay, secretion of (vascular endothelial growth factor)VEGF by (enzyme-linked immunosorbent assay) ELISA and the activities of MMP (matrix metalloproteinase) 2 and MMP9 by gelatine zymography. And the expressions of mRNA and proteins of MMP2, MMP9 and VEGF were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot respectively. RESULTS: After a treatment of zoledronic acid at 2.5, 5, 10, 20 and 40 mol/L for 48 h or 72 h, the highest inhibition rate of proliferation at approximately 50% was observed in the 40 mol/L group after 72 h. The inhibitory effect was not in a dose/time-dependent manner. After a 24-hour treatment of zoledronic acid at different concentrations (0, 10, 20 and 40 mol/L), the numbers of membrane-invading cells were 75.8 ± 2.6, 54.8 ± 5.4, 44.6 ± 6.4 and 38.6 ± 8.2 respectively (all P < 0.01). Gelatinase zymography demonstrated that the activities of MMP2 and MMP9 were inhibited significantly only in cells treated at 0 µmol/L. After a 24-hour exposure to zoledronic acid at 0, 10, 20 and 40 µmol/L, the concentrations of VEGF in supernatant were (5264 ± 89), (4626 ± 30), (4155 ± 40) and (1908 ± 171) g/L respectively (all P < 0.01). The expressions of mRNA and protein of MMP2, MMP9 and VEGF were down-regulated. CONCLUSION: Zoledronic acid can inhibit the in vitro proliferation and invasion of HNE1 cell through suppressing the secretion of VEGF, the activities of MMP2 and MMP9 and the expressions of VEGF, MMP2 and MMP9.

Co-expression of VEGF-C and survivin predicts poor prognosis in esophageal squamous cell carcinoma.

BACKGROUND: Lymphatic metastasis is one of the main factors affecting prognosis in esophageal squamous cell carcinoma (ESCC). Vascular endothelial growth factor-C (VEGF-C) is an important factor that promotes lymphangiogenesis. Survivin also plays a significant role in lymphatic invasion. However, the role and mechanism of their co-expression are still unclear in ESCC. The purpose of this study was to investigate whether the co-expression of VEGF-C and survivin could be a potential marker to predict patient prognosis and survival in ESCC. METHODS: The levels of VEGF-C, vascular endothelial growth factor receptor 3 (VEGFR-3), survivin, and Ki-67 were determined by immunohistochemistry (IHC) in 97 ESCC patient tumors. The correlations of co-expression of VEGF-C and survivin with pathological features and survival results were also assessed. RESULTS: High VEGF-C expression was observed in 64.9% of the patients and significantly correlated with T stage (P=0.024), node status (P=0.038), and lymph node metastasis (P=0.015). High survivin expression was significantly associated with T stage (P=0.013), N stage (P=0.016), lymph node metastasis (P=0.005), and differentiation (P=0.044) in 67.0% of the patients. Co-expression of VEGF-C and survivin (V+S+) was significantly associated with T stage (P<0.001), N stage (P=0.015), lymph node metastasis (P=0.003), differentiation (P=0.0045), and Ki-67 levels (P=0.024). High expression of VEGF-C or survivin was associated significantly with worse disease-free survival (DFS) and overall survival (OS) (P<0.05). Moreover, the V+S+ group had a worse DFS (P<0.001) and OS (P=0.001) than any other group (i.e., V-S-, V+S-, V-S+). Furthermore, multivariate DFS analyses (95% CI: 1.147-2.220, P=0.006) and multivariate OS analyses (95% CI: 1.080-2.193, P=0.017) revealed that co-expression of VEGF-C and survivin was an independent prognostic factor in ESCC patients. CONCLUSIONS: Co-expression of VEGF-C and survivin was predictive of poor prognosis in ESCC. Combined detection of VEGF-C and survivin could represent a feasible and effective marker to predict the prognosis and survival of ESCC patients.

Corrigendum: TRPC1 Inhibits Cell Proliferation/Invasion and Is Predictive of a Better Prognosis of Esophageal Squamous Cell Carcinoma.

[This corrects the article DOI: 10.3389/fonc.2021.627713.].

TRPC1 Inhibits Cell Proliferation/Invasion and Is Predictive of a Better Prognosis of Esophageal Squamous Cell Carcinoma.

BACKGROUND AND OBJECTIVES: In China, over 90% of esophageal cancer (EC) cases are esophageal squamous cell carcinoma (ESCC). ESCC is a frequently malignant tumor with poor prognosis despite the development of comprehensive therapeutic strategies, for which there is still a lack of effective prognostic factors. Previous studies found that the abnormal expression of TRPC1 is closely related to the proliferation, invasion, metastasis, and differentiation of various tumors. However, the relationship between TRPC1 and ESCC is currently unclear. The present study aimed to clarify the clinical significance of TRPC1 and to preliminarily assess the molecular mechanism by which TRPC1 regulates cell proliferation, migration, and invasion in ESCC. MATERIALS AND METHODS: Immunohistochemistry (IHC) was used to determine the expression of TRPC1 and Ki-67 in 165 cases of ESCC. The correlations between TRPC1 expression and clinicopathological characteristics were determined, and both univariate and multivariate analyses were utilized to quantify the impact of TRPC1 expression on patient survival. Cell Counting Kit-8, scratch wound healing, and transwell assays were used to determine the effects of TRPC1 on proliferation, migration, and invasion in ESCC in vitro, respectively. RESULTS: The positive expression rate of TRPC1 showed significantly decreased in ESCC (45.50%) compared with the levels in normal esophageal mucosa (NEM; 80.80%) and high-grade intraepithelial neoplasia (HGIEN; 63.20%) (P<0.001). Higher expression rate of TRPC1 was associated with low lymph node metastasis (P<0.001), high differentiation (rs = 0.232, P=0.003), and low Ki-67 (rs = -0.492, P<0.001). We further revealed that low expression of TRPC1 was associated with poor prognosis (Disease-free survival, DFS: 95% CI=0.545-0.845, P=0.001; Overall survival, OS: 95% CI=0.553-0.891, P=0.004). Furthermore, we showed that downregulation of TRPC1 promoted the proliferation, migration, and invasion of human esophageal squamous cell carcinoma cell line EC9706 in vitro. In contrast, overexpression of TRPC1 inhibited the proliferation, migration, and invasion of human esophageal squamous cell carcinoma cell line KYSE150 (P<0.01), in a manner at least in part mediated through the AKT/p27 pathway. CONCLUSION: TRPC1 inhibited the proliferation, migration, and invasion of EC9706 and KYSE150 cells, at least, in part mediated through the AKT/p27 pathway in vitro. The downregulation of TRPC1 may be one of the most important molecular events in the malignant progression of ESCC. TRPC1 could be a new candidate tumor suppressor gene and a new prognostic factor of ESCC.

[Inhibitory effect of ginsenoside Rg3 on the tube-like structure formation in human nasopharyngeal carcinoma HNE-1 cell line in vitro].

OBJECTIVE: To study the anti-angiogenic effect of ginsenoside Rg3 (Rg3 in abbreviation) in human nasopharyngeal carcinoma HNE-1 cells in vitro. METHODS: The tube-like structure (TLS) formation of HNE-1 cells, cultured in medium with different concentrations of Rg3, was determined by in vitro anti-angiogenic test based on preliminary experiment observing the TLSs formed by HNE-1 cells on Matrigel and their structural characteristics. The VEGF expression level in HNE-1 cells was determined by immunohistochemistry (IHC) and Western-blot test after 48-hour cultured in medium with different concentrations of Rg3. RESULTS: HNE-1 cells could form TLSs and mosaic vessels when mix-cultured with CRL-2480 on Matrigel. Rg3 could inhibit the TLS formation of HNE-1 cells. After 24-hour culture in medium with Rg3 at concentrations of 0, 50, 100 and 200 µg/ml, the number of TLSs were 75.50 ± 6.86, 55.00 ± 11.92, 39.75 ± 7.93 and 24.50 ± 6.25, respectively, which were negatively correlated with the concentrations of Rg3 (r = -0.928; P < 0.01). After 48 hours of culture, the expressions of VEGF significantly declined by IHC test with results as 0.19 ± 0.03, 0.13 ± 0.02, 0.11 ± 0.01, and 0.08 ± 0.01, respectively, which were negatively correlated with the concentrations of Rg3 (r = -0.911; P < 0.01). The expressions of VEGF also gradually decreased as revealed by Western blot test, with corresponding results as 119.49, 111.51, 86.45, and 38.29. All of the tests showed significantly declined results in the group at the concentration of 200 µg/ml Rg3. CONCLUSION: Rg3 can inhibit the vasculogenic mimicry of HNE-1 cells, and the possible mechanism might be associated with the down-regulation of VEGF protein expression in HNE-1 cells.

[Study on promoter methylation status of E-cadherin gene in nasopharyngeal carcinoma cell lines].

OBJECTIVE: To investigate the role of methylation on E-cadherin inactivation in nasopharyngeal carcinoma (NPC) cell line HNE1 and CNE2, as well as evaluate the inhibitory effect of 5-aza-2'-deoxycytidine (5-Aza-dC) on cell abilities of proliferation and invasion. METHODS: The expression level of E-cadherin was measured by RT-PCR, Western blot and immunohistochemistry (polymer method), the methyaltion status was analyzed by methylation-specific PCR (MSP), and cell proliferation and invasion were examined by MTT and invasion assay, separately before and after treatment with demethylating agent 5-Aza-dC. RESULTS: The expression level of E-cadherin was down-regulated compared with the normal tissue, simultaneously partially methylated in gene promoter. Treatment with 20 µmol/L 5-Aza-dC increased the expression of E-cadherin and reduced the methylation degree. Moreover, it also significantly suppressed cell growth (27.6% for HNE1 cells and 34.3% for CNE2 cells, P < 0.05) and invasiveness (37.2% for HNE1 cells and 29.7% for CNE2 cells, P < 0.05). CONCLUSIONS: Aberrant methylation around gene promoter region may play an important part in down regulation of E-cadherin in NPC, suggesting a potential therapeutic strategy for demethylating agents such as 5-Aza-dC.

Chronic cadmium exposure aggravates malignant phenotypes of nasopharyngeal carcinoma by activating the Wnt/ß-catenin signaling pathway via hypermethylation of the casein kinase 1α promoter.

BACKGROUND: Our previous study has shown that cadmium (Cd) exposure is not only a risk factor for nasopharyngeal carcinoma (NPC), but also correlated with the clinical stage and lymph node metastasis. However, the underlying molecular events of Cd involved in NPC progression remain to be elucidated. PURPOSE: The objective of this study was to decipher how Cd impacts the malignant phenotypes of NPC cells. METHODS: NPC cell lines CNE-1 and CNE-2 were continuously exposed with 1 µM Cd chloride for 10 weeks, designating as chronic Cd treated NPC cells (CCT-NPC). MTT assay, colony formation assay and xenograft tumor growth were used to assess cell viability in vitro and in vivo. Transwell assays were performed to detect cell invasion and migration. The protein levels of E-cadherin, N-cadherin, Vimentin as well as ß-catenin and casein kinase 1α(CK1α) were measured by Western blot. Immunofluorescence staining was used to observe the distribution of filament actin (F-actin), ß-catenin and CK1α. The mRNA levels of downstream target genes of ß-catenin were detected by RT-PCR. Wnt/ß-catenin signaling activity was assessed by TOPFlash/FOPFlash dual luciferase report system. MS-PCR was used to detect the methylation status of CK1α. Finally, the activation of Wnt/ß-catenin pathway and cell biological properties were examined following treatment of CCT-NPC cells with 5-aza-2-deoxy-cytidine(5-aza-CdR). RESULTS: CCT-NPC cells showed an increase in cell proliferation, colony formation, invasion and migration compared to the parental cells. Cd also induced cytoskeleton reorganization and epithelial-to-mesenchymal transition. Upregulation and nuclear translocation of ß-catenin and increased luciferase activity accompanied with transcription of downstream target genes were found in CCT-NPC cells. Treatment of CCT-CNE1 cells with 5-aza-CdR could reverse the hypermethylation of CK1α and attenuate the cell malignancy. CONCLUSION: These results support a role for chronic Cd exposure as a driving force for the malignant progression of NPC via epigenetic activation of the Wnt/ß-catenin pathway.

Osthole sensitizes with radiotherapy to suppress tumorigenesis of human nasopharyngeal carcinoma in vitro and in vivo.

BACKGROUND: Radiotherapy is one of the most comment and useful treatment for nasopharyngeal carcinoma (NPC), but the radioresistance remains a major obstacle. Osthole, a natural coumarin derivative, has been shown to have anti-tumor and anti-inflammatory activity. However, the relationship between osthole and NPC treatment, especially for radiotherapy, is still elusive. METHODS: Osthole with or without X ray radiotherapy treated with CNE2 cells, a human EC cell line. Cell viability, proliferation, migration and apoptosis were measured by MTT, colony formation, Annexin V/PI double staining, Transwell assay, respectively. NPC tumor models were established on BALB/c nude mice by subcutaneously injection of CNE2 cells and the effect of osthole and radiotherapy on tumor growth in vivo was studied. RESULTS: We found that in a dose-dependent manner, osthole could individually, and synergistically with radiotherapy, reduce NPC cell (CNE2) viability, proliferation, migration, and invasion, and induce apoptosis, respectively. This effect of anti-tumor growth and induction of apoptosis was further confirmed in mice induced by subcutaneously injection with CNE2 cells and following treated with osthole or/and radiation. CONCLUSION: Osthole increases the effect of radiotherapy on anti-human nasopharyngeal cancer.

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.

Cytogenetic and molecular genetic changes in malignant transformation of immortalized esophageal epithelial cells.

The purpose of this study was to evaluate the extent to which the expression of p53, c-myc, bcl-2, ras genes and chromosomes, along with activity of hTERT, impacts on the malignant transformation of immortalized esophageal epithelial cells. The SHEE cell line was established from an embryonic esophageal epithelial cell induced by transduction of E6E7 genes of human papillomavirus type 18 (HPV18E6E7). In cells of the 85th passage (SHEE85), the malignant transformation of SHEE was confirmed by morphology, cell proliferative index and tumor formation in SCID mice. C-myc, p53, bcl-2 and ras genes were assayed by the multi-PCR method with house-keeping gene GAPDH as control. The modal number of chromosomes was analyzed and its expression of subunit of telomerase, hTERT, was assessed by RT-PCR. Expression of HPV18E6E7 was assayed by Western blotting. The results showed that cells of SHEE85 were atypical and exhibited proliferative status with a proliferation index of 45.70%. Tumors formed in SCID mice with invasion of adjacent tissue. The karyotype belonged to hypotriploid and displayed expression of hTERT. C-myc, k-ras, bcl-2 and p53 (expression of phosphoprotein) were positive in SHEE85. Expression of HPV18E6E7 was positive. Taken together, SHEE85 cells were in fully malignant transformation and their molecular mechanism involved the expression of cellular genes, such as p53, bcl-2, c-myc and ras, and aberrance of chromosomes. It is probable that all of these changes were related with HPV18E6E7.

Morphological and functional changes of mitochondria in apoptotic esophageal carcinoma cells induced by arsenic trioxide.

AIM: To demonstrate that mitochondrial morphological and functional changes are an important intermediate link in the course of apoptosis in esophageal carcinoma cells induced by As2O3. METHODS: The esophageal carcinoma cell line SHEEC1, established in our laboratory, was cultured in 199 growth medium, supplemented with 100mL x L(-1) calf serum and 3 mol x L(-1)As2O3 (the same below). After 2, 4, 6, 12, 24 h of drug adding, the SHEEC1 cells were collected for light-and electron-microscopic examination. The mitochondria were labeled by Rhodamine fluorescence probe and the fluorescence intensity of the mitochondria was measured by flow cytometer and cytofluorimetric analysis. Further,the mitochondrial transmembrane potential (MTP, psim) change was also calculated. RESULTS: The mitochondrial morphological change after adding As2O3 could be divided into three stages. In the early-stage (2-6h) after adding As2O3, an adaptive proliferation of mitochondria appeared; in the mid-stage (6-12 h) a degenerative change was observed; and in the late-stage (12-24 h) the mitochondria swelled with outer membrane broken down and then cells death with apoptotic changes of nucleus. The functional change of the mitochondria indicated by fluorescent intensity, which reflected the MTP status of mitochondria, was in accordance with morphological change of the mitochondria. The fluorescent intensity increased at early-stage, declined in mid-stage and decreased to the lowest in the late-stage. 24 h after As2O3 adding, the cell nucleus showed typical apoptotic changes. CONCLUSION: Under the inducement of As2O3, the early apoptotic changes of SHEEC1 cells were the apparent morphological and functional changes of mitochondria, afterwards the nucleus changes followed. It is considered that changes of mitochondria are an important intermediate link in the course of apoptosis of esophageal carcinoma cells induced by As2O3.

Clinical importance and therapeutic implication of E-cadherin gene methylation in human ovarian cancer.

E-cadherin (E-cad) is widely expressed in epithelial cells and acts as a pivotal tumor suppressor. The promoter methylation of E-cad has been reported to closely relate to its downregulation in many kinds of cancers. E-cad expression and methylation status were detected by immunohistochemistry (IHC) and methylation-specific polymerase chain reaction (MS-PCR) in 50 ovarian cancer tissues. 5-Aza-2'-deoxycytidine (5-Aza-dC) was used to demethylate E-cad in SKOV3 and ES2 ovarian cancer cell lines, of which the effect was verified by Western blot and MS-PCR. Then MTT and transwell experiments were conducted to detect the capacity of cell proliferation and migration for these cells. Downregulation of E-cad expression was observed in 60 % of ovarian cancer tissues (30/50) by IHC, whereas MS-PCR result indicated that E-cad was methylated in 64 % of (32/50) ovarian cancer specimens. And E-cad expression was significantly correlated with E-cad methylation (P = 0.004). 5-Aza-dC was used to process SKOV3 and ES2 ovarian cancer cell lines. By MTT experiment, we found that the proliferation of 5-Aza-dC-treated SKOV3 and ES2 was significantly suppressed by 28.0 % (P < 0.05) and 32.3 % (P < 0.05). By transwell experiment, the motility of SKOV3 and ES2 was found to be significantly suppressed by 38.2 and 27.4 % (P < 0.05), respectively, after treated with 5-Aza-dC. E-cad methylation is one of the main reasons for the expression reduction in ovarian cancer. 5-Aza-dC treatment could significantly restore the expression of E-cad and suppress growth and invasion of SKOV3 and ES2 cells. These results suggest E-cad methylation may be a promising target for ovarian cancer therapy.

Zoledronic acid inhibits proliferation and impairs migration and invasion through downregulating VEGF and MMPs expression in human nasopharyngeal carcinoma cells.

To demonstrate the effect of zoledronic acid in proliferation, invasion, and migration of human nasopharyngeal carcinoma cell HNE-1 and explore the potential role of VEGF, MMP-2, and MMP-9 proteins in vitro. Human nasopharyngeal carcinoma cell HNE-1 was exposed to various concentrations (0-40 µmol/l) of zoledronic acid. Zoledronic acid inhibited proliferation of HNE-1 cells though not in a dose-dependent manner. Zoledronic acid had exerted a dose-dependent effect on the migration and invasion of HNE-1 cells. Both expressions of mRNA and protein of MMP2, MMP9, and VEGF were reduced, respectively, detected by RT-PCR and Western blot assays. These data suggested that zoledronic acid not only inhibited growth but also invasion and migration of HNE-1 cells in vitro. The anti-cancer action of zoledronic acid was partially associated with the suppression of VEGF expression and secretion and downregulating the expression of MMP2 and MMP9.

Prevalence and association of human papillomavirus 16, Epstein-Barr virus, herpes simplex virus-1 and cytomegalovirus infection with human esophageal carcinoma: a case-control study.

Recent research shows esophageal carcinoma (EC) as the ninth most common malignancy in the world. The association of viral infection and EC has been reported in the last 30 years. However, geographic variation in infection rates and the key mechanisms of the viral action have yet to be resolved. This study aimed to determine the prevalence and association of human papillomavirus 16 (HPV-16), herpes simplex virus 1 (HSV-1), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection in the etiology of EC in the area of Shantou, Guangdong, China. Nested PCR was used to detect viral DNA in the mucosa of 70 cases of EC and in paracancerous tissues, as well as 100 cases of normal esophagus mucosa. Data were analyzed by χ2 test, Fisher's exact test and bivariate correlation analysis. The infection rates of HPV-16, HSV-1 and EBV were 40.0, 30.0 and 30.0%, respectively, in EC mucosa, and were significantly higher than those in normal mucosa. However, no CMV DNA was detected in either EC or normal mucosa. HPV-16 or EBV infection was mainly detected in EC patients 48-58 years old, and the infection rate was positively associated with pathological grade of EC (P<0.05). Tobacco smoking and alcohol consuption were high risk factors for HPV-16 infection for male patients [odds ratio (OR), 5.9; 95% confidence interval (CI), 1.4-24.6; OR = 3.8; 95% CI, 1.1-13.8]. Rates of infection with a mixture of these 3 viruses were all more than 10.0% in cancerous mucosa and closely related to the pathological grade of EC (P = 0.001). Infection with HPV-16, HSV-1 or EBV may be an important etiological factor in EC.

[The promotive effects of N-nitrosopiperidine on the malignant transformation of the immortalized esophageal epithelium induced by human papillomavirus].

BACKGROUND: Study on the promotive effects of N-nitrosopiperidine on carcinogenesis process was performed, based on the immortalization of human fetal esophageal epithelium induced by human papillomavirus (HPV) 18E6E7 genes. METHODS: The immortalized esophageal epithelium SHEE was induced by HPV18E6E7. The cells at 17th passages were cultured in 50 ml flasks. The N-nitrosopiperidine (NPIP) 0, 2, 4, 8 mmol/L added to the cultured medium of SHEE cells for 3 weeks. The morphology, proliferation and apoptosis of the cells were studied by phase contrast microscopy and flow cytometry. Modal number of chromosomes was analyzed by standard method. Tumorigenicity of the cells was assessed by soft agar colony formation and by transplantation of cells into nude mice. Expression of HPV was detected by Western blot. RESULTS: When cells were exposed to high concentration (8 mmol/L) of NPIP, cell death was increased, leaving a few live cells. In normal cultural medium instead of NPIP proliferative status of the cells restored after 4 weeks and the cells progressed to the proliferation stage with continuous replication and atypical hyperplasia. At the end of the 8th week, the cells appeared with large colonies in soft-agar and tumor formation in transplanted nude mice. When the cells were cultured in 2, 4 mmol/L NPIP the doubling passage was delayed and without tumor formation in transplanted nude mice. Modal number of chromosomes was 61-65, in 8 mmol/L NPIP group and control group, 56-61. Expression of HPV18 appeared in experimental and control groups. CONCLUSION: NPIP promotes malignant change of the immortalized esophageal epithelial cells induced by HPV18E6E7. HPV18E6E7 synergy with NPIP will accelerate malignant transformation in esophageal epithelium.