Intraperitoneal administration of a small interfering RNA targeting nuclear factor-kappa B with paclitaxel successfully prolongs the survival of xenograft model mice with peritoneal metastasis of gastric cancer.
ABSTRACT Activation of nuclear factor-kappa B (NF-kappaB) has been detected in various malignant tumors, including gastric carcinoma, and is associated with tumor growth, metastasis, resistance to chemotherapeutic agents and poor prognosis. Therefore, NF-kappaB is a potential target for antitumor therapy. In this study, we used a small interfering RNA (siRNA) to knockdown NF-kappaB p65 expression and determined whether intraperitoneal administration of NF-kappaB p65 siRNA and paclitaxel was effective for treating peritoneal metastasis of gastric cancer. Western blot analysis revealed that NF-kappaB p65 expression was diminished by NF-kappaB p65 siRNA. Apoptotic cells were increased after transfection of NF-kappaB p65 siRNA compared with control siRNA in the treatment with paclitaxel. In a murine xenograft model, abundant fluorescence was observed on the surface of intraperitoneal nodules of gastric cancer after siRNA administration. Moreover, intraperitoneal administration of NF-kappaB p65 siRNA reduced NF-kappaB expression in intraperitoneal nodules of gastric cancer. Finally, mice treated by intraperitoneal administration of NF-kappaB p65 siRNA and paclitaxel survived for a significantly longer time than mice treated by intraperitoneal administration of paclitaxel alone (p = 0.0002). Taken together, the present results demonstrate that intraperitoneal administration of NF-kappaB p65 siRNA and paclitaxel inhibited cancer growth in mice with peritoneal metastasis of gastric cancer. Therefore, intraperitoneal administration of NF-kappaB p65 siRNA and paclitaxel may provide a breakthrough in the treatment of peritoneal metastasis of gastric cancer.
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ABSTRACT: BACKGROUND: Intraperitoneal (i.p.) administration of paclitaxel is useful for treating malignant tumors with peritoneal dissemination, but the therapeutic efficacy is limited. Chemoresistance due to paclitaxel-induced nuclear factor-kappa B (NF-κB) activation is an important cause of suboptimal therapeutic efficacy. AIMS: The purpose of this study was to prove that addition of nafamostat mesilate (FUT-175), a synthetic serine protease inhibitor and an NF-κB inhibitor, to i.p. paclitaxel enhances antitumor effects of paclitaxel against gastric cancer with peritoneal dissemination. METHODS: In vitro, we assessed NF-κB activity and apoptosis in response to treatment with FUT-175 alone, paclitaxel alone, or a combination of FUT-175 and paclitaxel in a human gastric cancer cell line (MKN-45). In vivo, we established peritoneal dissemination in nude mice by i.p. injection of MKN-45 cells. The animals received i.p. injections of FUT-175 alone three times a week (FUT-175 group), of paclitaxel alone once a week (paclitaxel group), or a combination of FUT-175 and paclitaxel (combination group) three times and once a week, respectively. RESULTS: In the combination group, paclitaxel-induced NF-κB activation was inhibited and apoptosis was enhanced in comparison with those in the other groups both in vitro and in vivo. In the combination group, number and weight of peritoneal nodules were significantly lower than those in the paclitaxel group (p = 0.0009 and p = 0.0417, respectively). In the survival analysis, the combination group had a significantly better survival than the paclitaxel group (p = 0.0048). CONCLUSION: FUT-175 enhances the antitumor effect of i.p. paclitaxel against gastric cancer with peritoneal dissemination by inhibiting NF-κB activation in mice.Digestive Diseases and Sciences 07/2012; · 2.26 Impact Factor
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ABSTRACT: Smad interacting protein 1 (SIP1) is an epithelial-mesenchymal transition (EMT)-inducible gene that plays a key role in tumor progression in various cancers. This study seeks to clarify the clinical and biological significance of SIP1 expression, especially in intestinal type gastric cancer. We analyzed the mRNA levels of SIP1 and other EMT regulators by real-time reverse transcription PCR in gastric tissue samples of 134 gastric cancer patients, and in five gastric cancer cell lines. SIP1 gene knockdown by siRNA transfection was performed to evaluate SIP1 function in gastric cancer cells. Expression of the SIP1 gene was significantly higher in cancerous tissue than in adjacent normal mucosa. Although the mRNA expression of the other EMT regulators tested (Snail, Slug, and Twist) was not correlated with clinicopathological factors, increased SIP1 expression was an independent prognostic factor and an independent risk factor for peritoneal dissemination. In addition, SIP1 expression was significantly positive and correlated with vimentin expression. For intestinal type gastric cancer in particular, elevated SIP1 expression was significantly correlated with peritoneal dissemination and poor prognosis (p < 0.05). In vitro, cell proliferation, migration, invasion, and resistance to anoikis were significantly inhibited in SIP1 siRNA-transfected MKN7 cells compared to control siRNA. SIP1 appears to play an important role in progression to peritoneal carcinomatosis and may be a therapeutic target for patients with intestinal type gastric cancer.Clinical and Experimental Metastasis 11/2012; · 3.46 Impact Factor
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ABSTRACT: The prognosis of patients with advanced diffuse-type gastric cancer (GC, especially scirrhous gastric cancer (SGC) remains extremely poor. Peritoneal carcinomatosis is a frequent form of metastasis of SGC. With survival rates of patients with peritoneal metastasis at 3 and 5 years being only 9.8% and 0%, respectively, development of a new treatment is urgently crucial. For such development, the establishment of a therapeutic mouse model is required. Among the 11 GC cell lines we examined, HSC-60 showed the most well-preserved expression profiles of the Hedgehog and epithelial-mesenchymal transition pathways found in primary SGCs. After 6 cycles of harvest of ascitic tumor cells and their orthotopic inoculation in scid mice, a highly metastatic subclone of HSC-60, 60As6 was obtained, by means of which we successfully developed peritoneal metastasis model mice. The mice treated with small interfering (si) RNA targeting NEDD1, which encodes a gamma-tubulin ring complex-binding protein, by the atelocollagen-mediated delivery system showed a significantly prolonged survival. Our mouse model could thus be useful for the development of a new therapeutic modality. Intraperitoneal administration of siRNAs of targeted genes such as NEDD1 could provide a new opportunity in the treatment of the peritoneal metastasis of SGC.Cancer Science 10/2012; · 3.53 Impact Factor