Promising xenograft animal model recapitulating the features of human pancreatic cancer.

BACKGROUND: Multiple sites of metastasis and desmoplastic reactions in the stroma are key features of human pancreatic cancer (PC). There are currently no simple and reliable animal models that can mimic these features for accurate disease modeling. AIM: To create a new xenograft animal model that can faithfully recapitulate the features of human PC. METHODS: Interleukin 2 receptor subunit gamma (IL2RG) gene knockout Syrian hamster was created and characterized. A panel of human PC cell lines were transplanted into IL2RG knockout Syrian hamsters and severe immune-deficient mice subcutaneously or orthotopically. Tumor growth, local invasion, remote organ metastasis, histopathology, and molecular alterations of tumor cells and stroma were compared over time. RESULTS: The Syrian hamster with IL2RG gene knockout (named ZZU001) demonstrated an immune-deficient phenotype and function. ZZU001 hamsters faithfully recapitulated most features of human PC, in particular, they developed metastasis at multiple sites. PC tissues derived from ZZU001 hamsters displayed desmoplastic reactions in the stroma and epithelial to mesenchymal transition phenotypes, whereas PC tissues derived from immune-deficient mice did not present such features. CONCLUSION: ZZU001 hamsters engrafted with human PC cells are a superior animal model compared to immune-deficient mice. ZZU001 hamsters can be a valuable animal model for better understanding the molecular mechanism of tumorigenesis and metastasis and the evaluation of new drugs targeting human PC.

[Antitumour efficacy of a novel oncolytic adenovirus Ad-TD-RFP for human nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the antitumor efficacy of Ad-TD-RFP for human nasopharyngeal carcinoma cells (C666-1) in vitro and in vivo. METHODS: The oncolytic effects of Ad-TD-RFP and control virus dl11520 on C666-1 cells were determined by cytotoxicity assay (MTS assay). Viral replication of Ad-TD-RFP and dl11520 was detected at different time points (24 h, 48 h, 72 h and 96 h) by tissue culture infective dose (TCID(50)) in C666-1 cells implanted subcutaneously into the flank in each of BALB/c nude mice. The xenografts were injected intratumorally with Ad-TD-RFP or dl1520 to investigate their effects on tumor growth. RESULTS: The concentration for 50% of maximal effect (EC(50)) values of Ad-TD-RFP and dl1520 were (107.6 ± 3.2) pt/cell and (174.1 ± 4.0) pt/cell, respectively (t = 22.6, P < 0.001). The Ad-TD-RFP replication was 3-14 folds more than dl1520 replication at four time points (24 h, 48 h, 72 h and 96 h) in C666-1 cells (t values were 33.6, 23.4, 20.8 and 17.3, respectively, P < 0.001). The average tumor volumes of PBS group, dl1520 group and Ad-TD-RFP group were (1765.5 ± 713.9) mm(3), (1036.9 ± 623.8) mm(3), and (420.8 ± 238.7) mm(3), respectively (F = 12.0, P < 0.05) on day 67 after treatment. CONCLUSIONS: The antitumour efficacy of the novel oncolytic adenovirus Ad-TD-RFP for human nasopharyngeal carcinoma C666-1 cells is superior to that of dl1520 in vitro and in vivo. The outcome of this study provides an experimental basis for the treatment of human nasopharyngeal carcinoma by viral gene therapy.

[Promoting effect of all-trans retinoic acid on the chemosensitivity of esophageal cancer EC9706 cells].

OBJECTIVE: To investigate the impact of all-trans retinoic acid (ATRA) on chemosensitivity to esophageal squamous cell carcinoma EC9706 cells in vitro and its mechanism. METHODS: EC9706 cells were routinely cultured as the control group. The experimental group was divided into three groups. The ATRA group with ATRA in final concentration of 1 µmol/L; the 5-Fu group with 5-Fu in final concentration of 50 mg/L; the combined treatment group with ATRA in final concentration of 1 µmol/L and 5-Fu 50 mg/L. The cell apoptosis was detected by terminal deoxynucleotidy transferase mediated dUTP nick end labelling (TUNEL). The cell cycle and apoptosis were detected by flow cytometry. RESULTS: The results of TUNEL showed that in the combined treatment group appeared a large number of apoptotic cells, and their nuclei were stained brown, with a positive rate of 89.7%. There was a significant difference in the comparison with the ATRA group (38.3%) and 5-Fu group (40.3%) (P < 0.05). The flow cytometry showed that the ATRA + 5-Fu group had a significantly higher apoptosis rate (76.9% ± 2.7%) than that in the ATRA group (38.2% ± 2.6%) and 5-Fu group (45.2% ± 2.3%) (P < 0.05). The ratio of cells in G(1) phase increased in the ATRA + 5-Fu group (83.4% ± 3.0%), significantly higher than (48.2% ± 2.5%) in the ATRA group and (53.2% ± 2.6%) in the 5-Fu group (P < 0.05). The ratio of cells in S + G(2)/M phase was decreased in the ATRA + 5-Fu group, with a significant difference (P < 0.05) when compared with other groups. There was no significant difference between the ATRA group and 5-Fu group (P > 0.05) in the apoptosis rate and the proportion of cells at different phases. CONCLUSION: ATRA can induce apoptosis of esophageal carcinoma EC9706 cells in vitro. The combination of ATRA and 5-Fu may enhance the chemotherapeutic efficacy.

[Mechanism of apoptosis of esophageal cancer EC9706 in nude mice induced by all-trans retinoic acid].

OBJECTIVE: To investigate the mechanism of apoptosis of EC9706 tumor-bearing nude mice induced by all-trans retinoic acid (ATRA). METHODS: Human esophageal carcinoma cell line EC9706 cells were inoculated into nude mice to establish the solid tumor model. The tumor models were divided into the following groups: ATRA group, fluorouracil group, the two-drugs combination group, and with an equal volume fraction of solvent as the control group. The nude mice were sacrificed after 10 days of medication. TUNEL staining was used to detect cell apoptosis. RT-PCR was used to detect the expression level of mRNA and immunohistochemistry was used to detect the expression level of protein of caspase-3 and survivin, the apoptosis-related genes in the tumor tissue. RESULTS: The apoptosis rates of the ATRA group, 5-Fu group and ATRA + 5-Fu group were 44.3%, 39.7% and 91.0%, respectively. There was a significant difference in comparison with the control group (0.7%), and the ATRA group had no significant difference compared with that of the fluorouracil group (P > 0.05), but the apoptosis rate of the two-drugs combination group was significantly higher than that in the two single-drug groups (P < 0.05). The average gray value of caspase-3 protein expressed in the control group was 46.12 ± 0.33 and the relative expression of caspase-3 mRNA was 0.14 ± 0.03, both were significantly lower than that in the ATRA group, 5-Fu group and the two-drugs combination group (P < 0.05). The average gray value of survivin protein expressed in the control group was 96.07 ± 0.13 and the relative expression of survivin mRNA was 0.84 ± 0.04, both were significantly higher than those of other groups (P < 0.05). The ATRA group had no significant difference compared with the fluorouracil group (P > 0.05), but the two-drugs combination group was significantly different compared with the single-drug groups (P < 0.05). CONCLUSION: Apoptosis in the EC9706 tumor cells in nude mice can be induced by ATRA. The mechanism may be related with down-regulation of the level of survivin gene expression and up-regulation of the level of caspase-3 gene expression.

[Mutation and protein expression of PTEN gene in cervical adenocarcinoma and glandular intraepithelial neoplasia].

OBJECTIVE: To investigate PTEN expression and mutation status in the development of cervical adenocarcinoma. METHODS: Immunohistochemistry study of PTEN protein was performed on 42 cases of cervical adenocarcinoma, 20 cases of cervical glandular intraepithelial neoplasia and 28 cases of normal cervix tissue samples. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was used to detect the presence of mutation of exons 5 and 8 of PTEN gene. RESULTS: Positive expression rates of PTEN protein were 54.8% (23/42), 25.0% (5/20) and 100% (28/28) in cervical adenocarcinoma, cervical glandular intraepithelial neoplasia and normal cervix tissues, respectively. There were significant differences among the 3 groups (P < 0.05). Positive expression rates of PTEN protein were 47.4% (9/19), 20.0% (2/10) and 92.3% (12/13) in mucinous, endometrioid and the other variants of cervical adenocarcinoma, respectively. Mutation rates at exon 5 and exon 8 of PTEN gene were 19.0% (8/42), 45.0% (9/20) and 0 in cervical adenocarcinoma, cervical glandular intraepithelial neoplasia and normal cervix tissue, respectively. There were significant differences among 3 groups (chi(2) = 4.29, chi(2) = 12.70; P < 0.05). The mutation rates were 21.1% (4/19) and 40.0% (4/10) in mucinous and endometrioid variants of cervical adenocarcinoma, respectively. There was no mutation at exons 5 and 8 of PTEN gene detected in other variants of cervical adenocarcinoma. CONCLUSION: The development of cervical adenocarcionomas is correlated with the mutation and absence of the protein expression of PTEN, likely in the early phase of their carcinogenesis.

[Expression of nucleostemin mRNA and protein in the esophageal squamous cell carcinoma].

OBJECTIVE: To investigate the mRNA and protein expression of nucleostemin (NS) in human esophageal squamous cell carcinoma. METHODS: The mRNA and protein expression of NS were detected in 31 mucosal atypical hyperplasia specimens, 62 esophageal squamous cell carcinoma specimens and the matched normal esophageal mucosa samples by RT-PCR and immunohistochemistry method, respectively. RESULTS: The positive expression rate of NS protein in normal esophageal mucosa, atypical hyperplasia and esophageal squamous cell carcinoma was 17.7% (11/62), 41.9% (13/31) and 69.4% (43/62), respectively. There was a significant difference among the above three groups (chi2 = 33.676, P < 0.01). The expression levels of NS mRNA in esophageal squamous cell carcinoma (0.971 +/- 0.121) was significantly higher than that in the atypical hyperplasia (0.913 +/- 0.085) and also in the normal esophageal mucosa (0.866 +/- 0.103; F = 14.829, P < 0.01). The expression level of both NS protein and mRNA was positively correlated with histological grade, infiltration depth, and lymph node metastasis (P < 0.05), but not with age, gender or pathological type (P > 0.05). CONCLUSION: Our results indicate that nucleostemin mRNA and protein are over-expressed in human esophageal squamous cell carcinoma, and it may be related with its oncogenesis.

[mRNA expression level of nucleostemin in esophageal squamous cell carcinoma tissue].

OBJECTIVE: To investigate the mRNA expression levels of nucleostemin (NS) in human esophageal squamous cell carcinoma tissue. METHODS: Real-time PCR was used to quantify the mRNA expression of NS in the samples of esophageal squamous cell carcinoma tissue and their matched normal esophageal mucosa tissue from 62 patients, 36 males and 26 females, aged (61 +/- 10) (38-75). The relationship between NS mRNA expression level and clinical pathological features was analyzed. RESULTS: The NS mRNA expression level of the 62 cases of esophageal squamous cell carcinoma tissue was(4.5 +/- 2.1), significantly higher than that of the matched normal esophageal mucosa tissue [(2.1 +/- 1.3), t = -5.045, P = 0.000]. The mRNA expression level of NS was associated with tumor grade, depth of infiltration, and lymph node metastasis (all P < 0.05), but not with gender, age, and pathological type (all P > 0.05). Multiple linear regression analysis revealed that clinical and pathological features influenced the NS mRNA expression level (P = 0. 000), and the depth of infiltration and lymph node metastasis were important influencing factors for NS mRNA expression level(both P < 0.05). CONCLUSION: NS may play an important role in the progression and proliferation of esophageal squamous cell carcinoma.

Correlation of matrix metalloproteinase suppressor genes RECK, VEGF, and CD105 with angiogenesis and biological behavior in esophageal squamous cell carcinoma.

AIM: To explore the expression of reversion inducing cysteine-rich protein with Kazal motifs (RECK), vascular endothelial growth factor (VEGF) and endoglin (CD105) protein and its correlation with occurrence, development, invasion and metastasis in esophageal squamous cell carcinoma (ESCC). METHODS: Streptavidin-peroxidase (SP) immunohisto-chemistry was used to detect expression of RECK and VEGF in 62 cases of ESCC, 31 cases of adjacent atypical hyperplastic epithelium and 62 cases of normal esophageal epithelium. CD105 Mb was used to assess microvessel density (MVD). RESULTS: The expression of RECK was closely correlated with histological grade, infiltrative depth and lymphatic metastasis in ESCC (P < 0.05). The expression of RECK decreased during cancer development: normal esophageal epithelium (85.5%, 53/62), adjacent atypical hyperplastic epithelium (71.0%, 22/31), and carcinoma (59.7%, 37/62). There was a significant difference among the groups (P < 0.05). The expression of VEGF protein was closely correlated with infiltrative depth and lymphatic metastasis in ESCC (P < 0.05). The expression of VEGF protein increased during cancer development: normal esophageal epithelium (29.0%, 18/62), adjacent atypical hyperplastic epithelium (54.8%, 17/31), and carcinoma (67.7%, 42/62). There was a significant difference among the groups (P < 0.05). MVDCD105 increased in accordance with histological grade, but there was no significant difference (grade I, 36.92 +/- 10.85; grade II, 37.65 +/- 9.50; and grade III, 38.06 +/- 12.19). The MVDCD105 was closely correlated with infiltration and lymphatic metastasis in ESCC (P < 0.05). The expression of RECK was inversely correlated with the expression of VEGF and CD105. CONCLUSION: RECK, VEGF and CD105 play important roles in the infiltration, metastasis and carcinogenesis in esophageal carcinoma. Angiogenesis in ESCC may be promoted by over-expression of CD105.

[Effects and mechanism of lutein on apoptosis of esophageal carcinoma EC9706 cells].

OBJECTIVE: To study the effects of lutein on apoptosis and its mechanism. METHOD: The cells of human esophageal carcinoma EC9706 were grown in RPMI medium containing 10% bovine serum and were treated with lutein at 100 microg x mL(-1) concentration. Flow cytometry was employed to investigate the effects of lutein on cell apoptosis of EC9706 cells. Histochemistry was performed to determine apoptosis-related protein expresion. RESULT: Flow cytometry analyses revealed that lutein increased EC9706 cell apoptosis ratio when treated with lutein 100 microg x mL(-1) at 96 h. Lutein decreased the expression of Bcl-2 protein and increased the expression of Bax protein in EC9706 cells. CONCLUSION: Lutein could inhibit mitosis and stimulate apoptosis of EC9706 cells. The apoptotic effect may result from the down-regulation of expression of Bcl-2 and up-regulation expression of Bax.

Expression of heparanase mRNA in anti-sense oligonucleotide-transfected human esophageal cancer EC9706 cells.

AIM: To investigate the effects of anti-sense oligonucleotides (ASODNs) on mRNA expression of heparanase in human esophageal cancer EC9706 cells. METHODS: One non-sense oligonucleotide (N-ODN) and five ASODNs against different heparanase mRNA sites were transfected into EC9706 cells, then the expression of heparanase mRNA in EC9706 cells was studied by in situ hybridization. RESULTS: The expression of heparanase mRNA could be inhibited by ASODNs. There was no significant difference among five ASODNs (P>0.05), but there was a significant difference between ASODNs and N-ODN or non-transfected group (ASODN1: 2.25+/-0.25, ASODN2: 2.21+/-0.23, ASODN3: 2.23+/-0.23, ASODN4: 2.25+/-0.24 vs N-ODN: 3.47+/-2.80 or non- transfected group: 3.51+/-2.93 respectively, P<0.05). CONCLUSION: The expression of heparanase mRNA in EC9706 cells can be inhibited by ASODNs in vivo, and heparanase ASODNs can inhibit metastasis of esophageal squamous cell carcinoma or other tumors by inhibiting the expression of heparanase.

[The relationship between intrathyroidal dendritic cells and humoral immune disorder in Graves' disease].

OBJECTIVE: To investigate the relationship between intrathyroidal dendritic cells and humoral immune disorder in Graves' disease. METHODS: With the use of S-100 protein antibodies and the help of SP immunohistochemical method, the number and distribution of S-100 protein positive dendritic cells were observed in thyroid glands from 34 patients with Graves' disease and 5 controls. Serum thyroid stimulating antibodies (TSAb) before operation were measured with human embryo-kidney cells expressing the recombinant thyrotrophin receptor. The correlation between the infiltrating degree of intrathyroidal dendritic cells and the values of serum TSAb was analyzed in patients with Graves' disease. RESULTS: In normal thyroid glands, no S-100 protein positive dendritic cells were found. Dendritic cells were seen in all observed thyroid glands from patients with Graves' disease. Most of the dendritic cells were seen in close contact with the adjacent thyroid epithelial cells or infiltrating lymphocytes. The infiltrating degree of intrathyroidal dendritic cells in Graves' disease correlated closely with the values of serum TSAb (r = 0.4461, P < 0.01). CONCLUSION: It is suggested that the intrathyroidal dendritic cells have a close relation with humoral immune disorder and play an important role in the initiation and/or maintenance of thyroid autoimmune reaction in Graves' disease.

Expression of human chorionic gonadotropin, CD44v6 and CD44v4/5 in esophageal squamous cell carcinoma.

AIM: To study the relationship between the expression of human chorionic gonadotropin (HCG), CD44v6, CD44v4/5 and the infiltration, metastasis of esophageal squamous cell carcinoma. METHODS: By labeled streptavidin-biotin technique, the expressions of HCG, CD44v6, and CD44v4/5 in 42 patients with esophageal squamous cell carcinoma were examined. RESULTS: The positive rate of HCG expression in patients with lymph node metastasis was 85.71% (18/21), higher than that (57.14%, 12/21) in those without lymph node metastasis (P<0.05). The positive rate of CD44v6 expression was 71.43% (15/21) in lymph node metastasis group, and 38.09% (8/21) in non-metastasis group; there was a significant difference between the two groups (P<0.05). The positive rate of CD44v4/5 expression was 76.19% (16/21) in lymph node metastasis group, and 42.86% (9/21) in non-metastasis group; there was also a significant difference between them (P<0.05). From grade I to grade III in differentiation, the positive rate of HCG expression was 84.62% (11/13), 70.59% (12/17) and 58.33% (7/12), respectively; there was no significant difference among them (P>0.05). The positive rate of CD44v6 expression in grades I-III of cancer tissues was 76.92% (10/13), 52.94% (9/17), and 33.33% (4/12) respectively; there was no significant difference among them. The positive rate of CD44v4/5 expression in grades I-III of cancer tissues was 69.23% (9/13), 64.71% (11/17), and 41.67% (5/12) respectively; there was no significant difference among the three groups. There was no correlation between the positive rates of HCG and CD44v6, CD44v4/5 expression. Cancer cells in carcinomatous emboli and those infiltrating into vascular wall strongly expressed HCG, CD44v6, and CD44v4/5. CONCLUSION: Expression of HCG, CD44v6, and CD44v4/5 in esophageal squamous cell carcinoma is related to its infiltration and metastasis. HCG, CD44v6, and CD44v4/5 have different effects on the infiltration and metastasis of esophageal squamous cell carcinoma.