Cancer spectrum in TP53-deficient golden Syrian hamsters: A new model for Li-Fraumeni syndrome.

BACKGROUND: The TP53 tumor suppressor gene is the most commonly mutated gene in human cancers. Humans who inherit mutant TP53 alleles develop a wide range of early onset cancers, a disorder called Li-Fraumeni Syndrome (LFS). Trp53-deficient mice recapitulate most but not all of the cancer phenotypes observed in TP53-deficient human cancers, indicating that new animal models may complement current mouse models and better inform on human disease development. MATERIALS AND METHODS: The recent application of CRISPR/Cas9 genetic engineering technology has permitted the emergence of golden Syrian hamsters as genetic models for wide range of diseases, including cancer. Here, the first cancer phenotype of TP53 knockout golden Syrian hamsters is described. RESULTS: Hamsters that are homozygous for TP53 mutations become moribund on average ~ 139 days of age, while hamsters that are heterozygous become moribund at ~ 286 days. TP53 homozygous knockout hamsters develop a wide range of cancers, often synchronous and metastatic to multiple tissues, including lymphomas, several sarcomas, especially hemangiosarcomas, myeloid leukemias and several carcinomas. TP53 heterozygous mutants develop a more restricted tumor spectrum, primarily lymphomas. CONCLUSIONS: Overall, hamsters may provide insights into how TP53 deficiency leads to cancer in humans and can become a new model to test novel therapies.

STAT1 interaction with E3-14.7K in monocytes affects the efficacy of oncolytic adenovirus.

Oncolytic viruses based on adenovirus type 5 (Ad5) have been developed as a new class of therapeutic agents for cancers that are resistant to conventional therapies. Clinical experience shows that these agents are safe, but virotherapy alone has not achieved long-term cure in cancer patients. The vast majority of oncolytic adenoviruses used in clinical trials to date have deletion of the E3B genes. It has been demonstrated that the antitumor potency of the E3B-deleted mutant (dl309) is inferior to adenovirus with E3B genes intact. Tumors treated with dl309 show markedly greater macrophage infiltration than E3B-intact adenovirus. However, the functional mechanisms for this were not previously known. Here, we demonstrate that deletion of E3B genes increases production of chemokines by monocytes after adenovirus infection and increases monocyte migration. The E3B 14,700-Da protein (E3B-14.7K) inhibits STAT1 function by preventing its phosphorylation and nuclear translocation. The STAT1 inhibitor, fludarabine, rescues the effect of E3B-14.7K deletion by downregulating target chemokine expression in human and murine monocytes and results in an enhanced antitumor efficacy with dl309 in vivo. These findings have important implications for clinical use of E3B-deleted oncolytic adenovirus and other E3B-deleted adenovirus vector-based therapy.

[Expressions of Dab2 and ERK1 in esophageal carcinoma tissues and their clinical significance].

OBJECTIVE: To explore the expressions of protein and mRNA of disabled-2 (Dab2) and extracellular signal-regulated kinase1 (ERK1) in esophageal squamous cell carcinoma tissue (ESCC) and their clinical significance. METHODS: The expressions of protein and mRNA of Dab2 and ERK1 were detected in ESCC (n = 59), atypical hyperplasia (n = 27) and normal esophageal mucosa (n = 36) tissues by immunohistochemistry, in situ hybridization and reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The expressions of protein and mRNA of Dab2 were lesser in ESCC than those in atypical hyperplasia and normal esophageal mucosa tissues (23.7% vs 94.4%, 44.4% and 18.6% vs 97.2%, 33.3%). And the expressions of protein and mRNA ERK1 were higher in ESCC than those in atypical hyperplasia and normal esophageal mucosa tissues (81.4% vs 44.4%, 63.0% and 78.0% vs 30.6%, 51.9%) (all P < 0.05). Additionally, the expressions of protein and mRNA of Dab2 and ERK1 were closely related with lymph node metastasis in ESCC tissue and the expressions of protein and mRNA of ERK1 closely related with the depth of tumor invasion in ESCC tissue (all P < 0.05). Furthermore, the results of correlation analysis revealed that expressions of protein and mRNA of Dab2 and ERK1 in ESCC had a negative correlation (all P < 0.05). CONCLUSION: The expressions of protein and mRNA of Dab2 and ERK1 play important roles in the infiltration, metastasis and carcinogenesis of ESCC and their effects may be antagonistic to each other.

PRSS3 promotes tumour growth and metastasis of human pancreatic cancer.

BACKGROUND AND AIMS: Metastasis accounts for the poor outcome of patients with pancreatic cancer. We recently discovered PRSS3 to be over-expressed in metastatic human pancreatic cancer cells. This study aimed to elucidate the role of PRSS3 in the growth and metastasis of human pancreatic cancer. METHODS: PRSS3 expression in human pancreatic cancer cell lines was detected by qPCR and immunoblotting. The effect of PRSS3 on cancer cell proliferation, migration and invasion in vitro, tumour growth and metastasis in vivo were investigated by manipulation of PRSS3 expression in human pancreatic cancer cell lines. VEGF expression was detected by ELISA, and the pathway through which PRSS3 regulates VEGF expression was investigated. The therapeutic effect of targeting this pathway on metastasis was assessed in vivo. Immunohistochemistry was employed to detect PRSS3 expression in human pancreatic cancer tissues. RESULTS: PRSS3 was over-expressed in the metastatic PaTu8988s cell line, but not in the non-metastatic PaTu8988t cell line. Over-expression of PRSS3 promoted pancreatic cancer cell proliferation as well as invasion in vitro, and tumour progression and metastasis in vivo. Stepwise investigations demonstrated that PRSS3 upregulates VEGF expression via the PAR1-mediated ERK pathway. ERK inhibitor significantly delayed the progression of metastases of pancreatic cancer and prolonged the survival of animals bearing metastatic pancreatic cancer (p<0.05). 40.54% of human pancreatic cancers (n=74) were positive for PRSS3 protein. A significant correlation was observed between PRSS3 expression and metastasis (p<0.01). Multivariate Cox regression analysis indicated that patients with PRSS3 expression in their tumours had a shorter survival time compared to those without PRSS3 expression (p<0.05). CONCLUSION: PRSS3 plays an important role in the progression, metastasis and prognosis of human pancreatic cancer. Targeting the PRSS3 signalling pathway may be an effective and feasible approach for treatment of this lethal cancer.

[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.

A new oncolytic Vacciniavirus augments antitumor immune responses to prevent tumor recurrence and metastasis after surgery.

BACKGROUND: Local recurrence and remote metastasis are major challenges to overcome in order to improve the survival of patients with cancer after surgery. Oncolytic viruses are a particularly attractive option for prevention of postsurgical disease as they offer a non-toxic treatment option that can directly target residual tumor deposits and beneficially modulate the systemic immune environment that is suppressed post surgery and allows residual disease escape from control. Here, we report that a novel Vaccinia virus (VV), VVΔTKΔN1L (with deletion of both thymidine kinase (TK) and N1L genes) armed with interleukin 12 (IL-12), can prolong postoperative survival when used as a neoadjuvant treatment in different murine and hamster surgical models of cancer. METHODS: A tumor-targeted replicating VV with deletion of TK gene and N1L gene (VVΔTKΔN1L) was created. This virus was armed rationally with IL-12. The effect of VVΔTKΔN1L and VVΔTKΔN1L-IL12 on modulation of the tumor microenvironment and induction of tumor-specific immunity as well the feasibility and safety as a neoadjuvant agent for preventing recurrence and metastasis after surgery were assessed in several clinically relevant models. RESULTS: VVΔTKΔN1L can significantly prolong postoperative survival when used as a neoadjuvant treatment in three different surgery-induced metastatic models of cancer. Efficacy was critically dependent on elevation of circulating natural killer cells that was achieved by virus-induced cytokine production from cells infected with N1L-deleted, but not N1L-intact VV. This effect was further enhanced by arming VVΔTKΔN1L with IL-12, a potent antitumor cytokine. Five daily treatments with VVΔTKΔN1L-IL12 before surgery dramatically improved postsurgical survival. VVΔTKΔN1L armed with human IL-12 completely prevented tumor recurrence in surgical models of head and neck cancer in Syrian hamsters. CONCLUSIONS: These data provide a proof of concept for translation of the regime into clinical trials. VVΔTKΔN1L-IL12 is a promising agent for use as an adjuvant to surgical treatment of solid tumors.

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.

A Virus-Infected, Reprogrammed Somatic Cell-Derived Tumor Cell (VIReST) Vaccination Regime Can Prevent Initiation and Progression of Pancreatic Cancer.

PURPOSE: Pancreatic cancer remains one of the most lethal cancers, and late detection renders most tumors refractory to conventional therapies. Development of cancer prophylaxis may be the most realistic option for improving mortality associated with this disease. Here, we develop a novel individualized prophylactic and therapeutic vaccination regimen using induced pluripotent stem cells (iPSC), gene editing, and tumor-targeted replicating oncolytic viruses. EXPERIMENTAL DESIGN: We created a Virus-Infected, Reprogrammed Somatic cell-derived Tumor cell (VIReST) regime. iPSCs from healthy cells were induced to pancreatic tumor cells using in situ gene editing via stable provision of KRas G12D and p53 R172H tumor driver mutations. These cells were preinfected with oncolytic Adenovirus (AdV) as prime or Vaccinia virus (VV) as boost, to improve vaccine immunogenicity, prior to delivery of vaccines in a sequential regime to young KPC transgenic mice, genetically programmed to develop pancreatic cancer, to prevent and delay disease development. RESULTS: Tumor cells preinfected with oncolytic AdV as prime or VV as boost were the best regime to induce tumor-specific immunity. iPSC-derived tumor cells were highly related in antigen repertoire to pancreatic cancer cells of KPC transgenic mice, suggesting that an individual's stem cells can provide an antigenically matched whole tumor cell vaccine. The VIReST vaccination primed tumor-specific T-cell responses, resulting in delayed disease emergence and progression and significantly prolonged survival of KPC transgenic mice. Importantly, this regime was well-tolerated and nontoxic. CONCLUSIONS: These results provide both proof of concept and a robust technology platform for the development of personalized prophylactic cancer vaccines to prevent pancreatic malignancies in at-risk individuals.

Treatment and Prevention of Lung Cancer Using a Virus-Infected Reprogrammed Somatic Cell-Derived Tumor Cell Vaccination (VIReST) Regime.

Lung cancer is one of the most commonly diagnosed cancer and despite therapeutic advances, mortality remains high. The long period of clinical latency associated with lung cancer provides an ideal window of opportunity to administer vaccines to at-risk individuals that can prevent tumor progression and initiate long-term anti-tumor immune surveillance. Here we describe a personalized vaccination regime that could be applied for both therapeutic and prophylactic prevention of lung cancer, based on the derivation of lung cancer cells from induced pluripotent stem cells. Stem cells from healthy mice were modified to express Cre-dependent KRASG12D and Trp53R172H prior to differentiation to lung progenitor cells. Subsequent viral delivery of Cre caused activation of exogenous driver mutations, resulting in transformation and development of lung cancer cells. iPSC-derived lung cancer cells were highly antigenically related to lung cancer cells induced in LSL-KRASG12D/+; Trp53R172H/+ transgenic mice and were antigenically unrelated to original pluripotent stem cells or pancreatic cancer cells derived using the same technological platform. For vaccination, induced lung cancer cells were infected with oncolytic Adenovirus or Vaccinia virus, to act as vaccine adjuvants, prior to delivery of vaccines sequentially to a murine inducible transgenic model of lung cancer. Application of this Virus-Infected, Reprogrammed Somatic cell-derived Tumor cell (VIReST) regime primed tumor-specific T cell responses that significantly prolonged survival in both subcutaneous post-vaccine challenge models and induced transgenic models of lung cancer, demonstrating that stem cell-derived prophylactic vaccines may be a feasible intervention for treatment or prevention of lung cancer development in at-risk individuals.

[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.

Author Correction: Re-designing Interleukin-12 to enhance its safety and potential as an anti-tumor immunotherapeutic agent.

The originally published version of this Article contained errors in Figure 4. In panel b, the square and diamond labels associated with the uppermost survival curve were incorrectly displayed as 'n' and 'u', respectively. These errors have now been corrected in both the PDF and HTML versions of the Article.

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.

Re-designing Interleukin-12 to enhance its safety and potential as an anti-tumor immunotherapeutic agent.

Interleukin-12 (IL-12) has emerged as one of the most potent agents for anti-tumor immunotherapy. However, potentially lethal toxicity associated with systemic administration of IL-12 precludes its clinical application. Here we redesign the molecule in such a way that its anti-tumor efficacy is not compromised, but toxic effects are eliminated. Deletion of the N-terminal signal peptide of IL-12 can effect such a change by preventing IL-12 secretion from cells. We use a newly designed tumor-targeted oncolytic adenovirus (Ad-TD) to deliver non-secreting (ns) IL-12 to tumor cells and examine the therapeutic and toxic effects in Syrian hamster models of pancreatic cancer (PaCa). Strikingly, intraperitoneal delivery of Ad-TD-nsIL-12 significantly enhanced survival of animals with orthotopic PaCa and cured peritoneally disseminated PaCa with no toxic side effects, in contrast to the treatment with Ad-TD expressing unmodified IL-12. These findings offer renewed hope for development of IL-12-based treatments for cancer.

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.