SummaryMesenchymal stem cells derived from the human umbilical cord matrix (hUCMSCs) have great potential for therapeutic use for multiple diseases. The strategy that uses therapeutic gene-transfected hUCMSCs as cellular vehicles for targeted biologic agent delivery has solved the problem of short half life or excessive toxicity of biological agent(s) in vivo. Interferon-β (IFN-β) has demonstrated a potent anti-tumor effect on many types of cancer cell lines in vitro. The aim of this study was to determine the anti-cancer effect of IFN-β gene-transfected hUCMSCs (IFN-β-hUCMSCs) on cells derived from bronchioloalveolar carcinoma, a subset of lung adenocarcinoma that is difficult to treat. The co-culture of a small number of IFN-β-hUCMSCs with the human bronchioloalveolar carcinoma cell lines H358 or SW1573 significantly inhibited growth of both types of carcinoma cell lines. The culture medium conditioned by these cells also significantly attenuated the growth of both carcinoma cells, but this attenuation was abolished by adding anti-IFN-β antibody. Finally, systemic administration of IFN-β-hUCMSCs through the tail vein markedly attenuated growth of orthotopic H358 bronchioloalveolar carcinoma xenografts in SCID mice by increasing apoptosis. These results clearly indicate that IFN-β-hUCMSCs caused cell death of bronchioloalveolar carcinoma cells through IFN-β production, thereby attenuating tumor growth in vivo. These results indicate that IFN-β-hUCMSCs are a powerful anti-cancer cytotherapeutic tool for bronchioloalveolar carcinoma.

The endogenous angiotensin II (Ang II) type 2 receptor (AT2) has been shown to mediate apoptosis in cardiovascular tissues. Thus, the aim of this study was to explore the anti-cancer effect of AT2 over-expression on lung adenocarcinoma cells in vitro using adenoviral (Ad), FuGENE, and nanoparticle vectors. All three gene transfection methods efficiently transfected AT2 cDNA into lung cancer cells but caused minimal gene transfection in normal lung epithelial cells. Ad-AT2 significantly attenuated multiple human lung cancer cell growth (A549 and H358) as compared to the control viral vector, Ad-LacZ, when cell viability was examined by direct cell count. Examination of annexin V by flow cytometry revealed the activation of the apoptotic pathway via AT2 over-expression. Western Blot analysis confirmed the activation of caspase-3. Similarly, poly (lactide-co-glycolic acid) (PLGA) biodegradable nanoparticles encapsulated AT2 plasmid DNA were shown to be effectively taken up into the lung cancer cell. Nanoparticle-based AT2 gene transfection markedly increased AT2 expression and resultant cell death in A549 cells. These results indicate that AT2 over-expression effectively attenuates growth of lung adenocarcinoma cells through intrinsic apoptosis. Our results also suggest that PLGA nanoparticles can be used as an efficient gene delivery vector for lung adenocarcinoma targeted therapy.

BackgroundPancreatic cancer is one of the most aggressive human malignancies, with a very poor prognosis. To evaluate the effect of angiotensin II (Ang II) type 2 receptor (AT2) expression in the host's body on the growth of pancreatic carcinoma, we have investigated the growth of mouse pancreatic ductal carcinoma grafts in syngeneic wild type and AT2 receptor-deficient (AT2-KO) mice.MethodsThe role of AT2 receptor-signaling in stromal cells on the growth of murine pancreatic carcinoma cells (PAN02) was studied using various in vitro and in vivo assays. In vivo cell proliferation, apoptosis, and vasculature in tumors were monitored by Ki-67 immunostaining, TUNEL assay, and von Willebrand factor immunostaining, respectively. In the co-culture study, cell proliferation was measured by MTT cell viability assay. All the data were analyzed using t-test and data were treated as significant when p < 0.05.ResultsOur results show that the growth of subcutaneously transplanted syngeneic xenografts of PAN02 cells, mouse pancreatic ductal carcinoma cells derived from the C57/BL6 strain, was significantly faster in AT2-KO mice compared to control wild type mice. Immunohistochemical analysis of tumor tissue revealed significantly more Ki-67 positive cells in xenografts grown in AT2-KO mice than in wild type mice. The index of apoptosis is slightly higher in wild type mice than in AT2-KO mice as evaluated by TUNEL assay. Tumor vasculature number was significantly higher in AT2-KO mice than in wild type mice. In vitro co-culture studies revealed that the growth of PAN02 cells was significantly decreased when grown with AT2 receptor gene transfected wild type and AT2-KO mouse-derived fibroblasts. Faster tumor growth in AT2-KO mice may be associated with higher VEGF production in stromal cells.ConclusionsThese results suggest that Ang II regulates the growth of pancreatic carcinoma cells through modulating functions of host stromal cells; Moreover, Ang II AT2 receptor signaling is a negative regulator in the growth of pancreatic carcinoma cells. These findings indicate that the AT2 receptor in stromal fibroblasts is a potentially important target for chemotherapy for pancreatic cancer.

Although we have demonstrated that Angiotensin II (Ang II) signaling plays a role in colon and lung tumorigenesis, the precise mechanisms by which Ang II stimulates tumorigenesis remain unclear. The aim of this study was to investigate the synergistic induction of COX-2 by Ang II and pro-inflammatory cytokines in lung fibroblasts. We also compared the efficiencies of Ang II-dependent COX-2 induction in lung epithelial cells and stromal cells. Ang II induced COX-2 expression in lung fibroblasts in a dose-dependent manner (10(-9) to 10(-7) M) through the Ang II subtype 1 receptor (AT(1)). In addition, Ang II synergistically stimulated the induction of COX-2 by pro-inflammatory cytokines, IL-1beta, or TNF-alpha. Our results indicate that the pro-tumorigenic function of Ang II is attributable, in part, to its strong stimulatory effect of COX-2 expression in lung fibroblasts in which synergistic stimulation with pro-inflammatory cytokines was evident. It is also suggested that the AT(1) receptor in lung fibroblasts may be a rational target for chemoprevention of lung cancer.

Two peptides derived from the C1B domain of protein kinase Cγ (PKCγ) were shown to associate with classical PKC isozymes and modulate their activities. These C1B peptides are designated C1B1 (amino acid residues 101-112) and C1B5 (residues 141-151). Since PKC enzyme activity is shown to be involved in colon cancer development, the effect of C1B peptides on the growth of various human colon cancer cell lines was examined in vitro and in vivo. Sub-micromolar to micromolar levels of both C1B peptides induced approximately 60-70% growth attenuation in multiple colon cancer cell lines in a soft agar tumor colony assay; however, C1B5 peptide was not cytotoxic to normal colon epithelial cells in two dimensional culture. The effect of C1B5 peptide on colony growth of COLO205 cells was reversed by treatment with the PKCα/β inhibitor, Ro-32-0432. C1B peptide treatment attenuated COLO205 cells via two mechanisms: 1) cell cycle arrest and 2) stimulation of apoptosis. This is evident in G 2 arrest and increases in levels of cleaved caspase 3 and p53 phosphorylated at serine 20. Intratumoral injection of C1B5 peptide (20 mg/kg/day, every three days) markedly attenuated the growth of subcutaneous xenografts of COLO205 cells in SCID mice by 76% compared with the control. Taken together, these results strongly suggest that C1B peptides have negligible effects on normal tissues but are potentially effective chemotherapeutic agents for colon cancer.