Inhibition of pancreatic carcinoma growth by adenovirus-mediated human interleukin-24 expression in animal model

Chronic Pancreatitis and the Development of Pancreatic Cancer

Pancreatitis is a fibro-inflammatory disorder of the pancreas that can occur acutely or chronically as a result of the activation of digestive enzymes that damage pancreatic cells, which promotes inflammation. Chronic pancreatitis with persistent fibro-inflammation of the pancreas progresses to pancreatic cancer, which is the fourth leading cause of cancer deaths across the globe. Pancreatic cancer involves cross-talk of inflammatory, proliferative, migratory, and fibrotic mechanisms. In this review, we discuss the role of cytokines in the inflammatory cell storm in pancreatitis and pancreatic cancer and their role in the activation of SDF1α/CXCR4, SOCS3, inflammasome, and NF-κB signaling. The aberrant immune reactions contribute to pathological damage of acinar and ductal cells, and the activation of pancreatic stellate cells to a myofibroblast-like phenotype. We summarize several aspects involved in the promotion of pancreatic cancer by inflammation and include a number of regulatory molecules that inhibit that process.

Immunogenicity moderation effect of interleukin-24 on myelogenous leukemia cells

Previous studies have shown that interleukin-24 (IL-24) has tumor-suppressing activity by multiple pathways. However, the immunogenicity moderation effect of IL-24 on malignant cells has not been explored extensively. In this study, we investigated the role of IL-24 in immunogenicity modulation of the myelogenous leukemia cells. Data show that myelogenous leukemia cells express low levels of immunogenicity molecules. Treatment with IL-24 could enhance leukemia cell immunogenicity, predominantly regulate leukemia cells to produce immune-associated cytokines, and improve the cytotoxic sensitivity of these cells to immune effector cells. IL-24 expression could retard transplanted leukemia cell tumor growth in vivo in athymic nude mice. Moreover, IL-24 had marked effects on downregulating the expression of angiogenesis-related proteins vascular endothelial growth factor, cluster of differentiation (CD) 31, CD34, collagen IV and metastasis-related factors CD147, membrane type-1 matrix metalloproteinase (MMP), and MMP-2 and MMP-9 in transplanted tumors. These findings indicated novel functions of this antitumor gene and characterized IL-24 as a promising agent for further clinical trial for hematologic malignancy immunotherapy.

Melanoma differentiation-associated gene-7 suppresses human gastric cancer cell invasion and migration

Gastric cancer is one of the most common types of cancer in the world. Patients with gastric cancer often respond poorly to conventional chemotherapies, therefore more comprehensive therapy is required. Melanoma differentiation-associated gene-7 (MDA-7), also termed interleukin-24, is a potent tumor suppressor gene. Numerous studies have demonstrated that MDA-7 suppresses the growth and induces the apoptosis of cancer cells. In the present study, the MDA-7 gene was transfected into human gastric cancer AGS cells using adenovirus. Transwell and wound healing assays were performed to evaluate AGS cell invasion and migration, respectively. Western blotting was used to detect the expression of epithelial (E)-cadherin, cluster of differentiation (CD)44 and matrix metalloproteinase (MMP)-2 and MMP-9 proteins. A recombinant virus package was successfully constructed, and it was verified using western blotting that exogenous MDA-7 was highly expressed in the AGS cells. MDA-7 overexpression inhibited invasion and migration, decreased CD44, MMP-2 and MMP-9 expression, and increased epithelial (E-)cadherin expression in the AGS cells. Results of the present study revealed that MDA-7 inhibits gastric cancer invasion and metastasis by inhibiting CD44, MMP-2 and MMP-9 expression and by promoting E-cadherin expression.

Adenovirus-mediated IL-24 confers radiosensitization to human lung adenocarcinoma in vitro and in vivo

The current paper aims to study the effect of adenovirus-mediated IL-24 (Ad-IL-24) on human lung adenocarcinoma in vitro and in vivo and determine its possible mechanism of action. The growth-suppressing and apoptosis-inducing effects of Ad-IL-24, radiotherapy, and Ad-IL-24+ radiotherapy (hereinafter referred to as the joint group) on SPC-A1 lung carcinoma cells were assessed by using 3-(4,5-dimethyliazolyl-2)-2,5-diphnyltetrazolium bromide and flow cytometry. A human lung model was established with SPC-A1 cells in nude mice. Groups of mice were subjected to multi-point injections to their tumors. Gross tumor volumes were measured dynamically. The ratios of tumor suppression and radiosensitization effect were evaluated according to the method of probability sum Q values. The expressions of Bax, Bcl-2, Survivin, and Caspase-3 in tumor samples were detected by immunohistochemistry. The ratios of inhibition and apoptosis in the joint group were higher than those in the individual Ad-IL-24 and radiotherapy groups. In vitro, the joint group suppressed tumor growth conspicuously, showing a weight inhibition rate of about 64 %. The expressions of FasL, Bax and Caspase-3 were upregulated in the joint group, while the expressions of Cox,Bcl-2,VEGF,CD34 and Survivin were downregulated. The current study proves that Ad-IL-24 suppresses growth of SPC-A1 cells both in vitro and in vivo. Its functions appear to be related to cell apoptosis and antiangiogenesis.

Lentivirus-mediated shRNA interference targeting vascular endothelial growth factor inhibits angiogenesis and progression of human pancreatic carcinoma

Angiogenesis is known to be essential to the survival, growth, invasion and metastasis of cancer cells. Vascular endothelial growth factor (VEGF) is an important factor regulating tumor angiogenesis. In the present study, we analyzed the effect of lentivirus-mediated shRNA interference targeting vascular endothelial growth factor (VEGF) on angiogenesis and progression in the pancreatic cancer cell line Patu8988 in vitro and in vivo. The study aimed to construct a recombinant lentivirus carrying targeted VEGF shRNA (LV-RNAi) to be used to transfect Patu8988 cells, and we investigated its anti-angiogenic and growth inhibitory effects on pancreatic cancer. VEGF expression was measured by RQ-PCR, western blotting and enzyme-linked immunosorbent assay (ELISA). In subcutaneous transplantation models, tumor volumes were determined, and the expression levels of VEGF and CD34 were assessed by immunohistochemistry. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) was used to determine apoptosis. In the orthotopic transplantation models, tumor volume and liver metastasis were determined. We successfully constructed LV-RNAi and confirmed that it knocked down the VEGF gene at the mRNA and protein levels in Patu8988 cells. In the subcutaneous transplantation models, tumors with low levels of VEGF expression exhibited reduced pancreatic carcinoma angiogenesis and growth, and the apoptotic index was significantly higher. In the orthotopic transplantation models, tumors with low levels of VEGF expression exhibited significantly reduced pancreatic carcinoma growth, but no significant difference was observed between the three mouse groups, LV-RNAi, LV-NC and the control, in regards to liver metastasis. In summary, lentivirus-mediated RNAi silencing of VEGF inhibited tumor angiogenesis and growth, and increased apoptosis of the pancreatic cancer cell line Patu8988. VEGF targeted gene silencing approach has the potential to serve as a novel treatment for pancreatic cancer.

Silencing of B7-H3 increases gemcitabine sensitivity by promoting apoptosis in pancreatic carcinoma

In numerous types of cancer, the expression of a novel member of the B7 ligand family, the B7-H3 immunoregulatory protein, has been correlated with a poor prognosis. In the present study, we investigated the role of B7-H3 in chemoresistance in pancreatic carcinoma. Silencing of B7-H3, through lentivirus-mediated delivery of stable short hairpin RNA, was observed to increase the sensitivity of the human pancreatic carcinoma cell line Patu8988 to gemcitabine as a result of enhanced drug-induced apoptosis. Overexpression of B7-H3 caused the cancer cells to be more resistant to the drug. Subsequently, we investigated the underlying mechanisms of B7-H3-mediated gemcitabine resistance, and found that the levels of survivin decreased in cells in which B7-H3 had been knocked down. In vivo animal experiments demonstrated that tumors in which B7-H3 had been knocked down displayed a slower growth rate compared with the control xenografts. Notably, gemcitabine treatment led to a strong antitumor activity in mice with tumors in which B7-H3 had been knocked down; however, this effect was only marginal in the control group. Furthermore, survivin expression was weak in gemcitabine-treated tumors in which B7-H3 had been knocked down and apoptosis was increased, as revealed by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick-end labeling (TUNEL) staining. In summary, the present study demonstrated that B7-H3 induces gemcitabine resistance in pancreatic carcinoma cells, at least partially by downregulating survivin expression. These results provide novel insights into the function of B7-H3 and encourage the design and investigation of approaches targeting this protein in treating pancreatic carcinoma.

B7-H3 overexpression in pancreatic cancer promotes tumor progression

B7-H3, a member of the B7-family molecules, plays an important role in adaptive immune responses. In addition, B7-H3 is also expressed in several types of human cancers and is correlated with the poor outcome of cancer patients. However, its exact role in cancer is not known. In the present study, we compared B7-H3 expression in normal pancreas and pancreatic cancer tissue specimens, and determined the effects of low B7-H3 expression on the human pancreatic cancer cell line Patu8988 using lentivirus-mediated RNA interference. B7-H3 expression in pancreatic specimens was determined by enzyme-linked immunosorbent assay (ELISA). A Patu8988 cell line with low B7-H3 expression was established by lentivirus-mediated RNA interference to investigate the effect of B7-H3 on cell proliferation, migration and invasion in vitro. By establishing subcutaneous transplantation tumor and orthotopic transplantation pancreatic cancer mouse models, the effect of B7-H3 on cell proliferation, migration and invasion was studied in vivo. B7-H3 in tissue samples was significantly higher in the pancreatic cancer group than in the normal pancreas group (mean ± SD, 193.6±9.352 vs. 87.74±7.433 ng/g; P<0.0001). B7-H3 knockdown by RNA interference decreased cell migration and Transwell invasion up to 50% in vitro. No apparent impact was observed on cell proliferation in vitro. In the subcutaneous transplantation tumor mouse model, the tumor growth rate was reduced by the knockdown of B7-H3. In the orthotopic transplantation pancreatic cancer mouse model, the effect of inhibiting metastasis by knocking down B7-H3 was assessed in terms of the average postmortem abdominal visceral metastatic tumor weight. This demonstrated that inhibition of B7-H3 expression reduced pancreatic cancer metastasis in vivo. In conclusion, B7-H3 is aberrantly expressed in pancreatic cancer. In addition to modulating tumor immunity, B7-H3 may have a novel role in regulating pancreatic tumor progression.

Anti-angiogenesis by lentivirus-mediated small interfering RNA silencing of angiopoietin-2 gene in pancreatic carcinoma

Angiopoietin-2 (Ang2) has been shown highly expressed in resected human pancreatic carcinoma samples, but the role of it is less clear. We were, therefore, interested in exploring the effects of Ang2 silencing on the angiogenesis and growth of pancreatic carcinoma. Lentivirus mediated Ang2 small hairpin RNA (LV-RNAi) were transfected into pancreatic carcinoma cell line MIA PaCa-2. Three groups were designed in this study: the control group (Mia PaCa-2 cells), the LV-NC group (cells transfected with the control GFP-lentivirus) and the LV-RNAi group (cells transfected with LV-RNAi). The mRNA and protein level of Ang2 gene were detected by real-time polymerase chain reaction and Western blot respectively. MTT assay and Flow Cytometry were used to detect the cell growth and apoptosis. Anti-angiogenesis effect was measured by chick embryo chorioallantoic membrane (CAM) assay. In nude mice bearing tumors, after treatment with intratumoral injection of LV-RNAi, mice growth and tumor volume were observed, and the expression of Ang2, VEGF and CD34 were measured by immunohistochemistry. Compared with the control group and the LV-NC group, the mRNA and protein level of Ang2 gene were successfully knocked down in LV- RNAi group. Also the vessel count was decreased in CAM assay after LV-RNAi transfection. Meanwhile, no obvious cell viability and apoptosis changes were found in MTT assay and Flow Cytometry, respectively. LV-RNAi inhibited pancreatic carcinoma angio- genesis and growth by downregulating the expression of VEGF and CD34. These findings demonstrate that Ang2 gene silencing may exert a anti-angiogenesis effect in vitro and in vivo, and Ang2 targeted gene therapy has the potential to serve as a novel way for pancreatic carcinoma treatment.