Antitumor effects of bevacizumab in combination with fluoropyrimidine drugs on human oral squamous cell carcinoma.

Vascular endothelial growth factor (VEGF) serves an important role in new blood vessel formation or angiogenesis, which is a critical event in tumor growth and metastasis. Bevacizumab is a humanized monoclonal antibody against VEGF-A, whereas S-1 is a fluoropyrimidine antineoplastic agent that induces apoptosis in various types of cancer cells. The present study evaluated the antitumor effects of bevacizumab in combination with 5-fluorouracil (5-FU) or S-1 against oral squamous cell carcinoma (OSCC) in vitro and in vivo. Two human OSCC cell lines were used, namely the high VEGF-A-expressing HSC-2 cells and the low VEGF-A-expressing SAS cells. MTT assay was used to evaluate the effect of bevacizumab and/or 5-FU against HSC-2 and SAS cell proliferation. Additionally, the antitumor effect of bevacizumab was evaluated alone and in combination with S-1 against HSC-2 tumors in nude mice. S-1 (6.9 mg/kg/day) was administered orally every day for 3 weeks, and bevacizumab (5 ml/kg/day) was injected intraperitoneally twice per week for 3 weeks. Apoptotic cells in mouse tumors were detected using the TUNEL method, and cell proliferation and microvessel density (MVD) were determined by immunohistochemical staining of Ki-67 and CD31, respectively. Bevacizumab alone did not inhibit OSCC cell proliferation in vitro, and did not exhibit any synergistic inhibitory effect in combination with 5-FU in vitro. However, combined bevacizumab and S-1 therapy exerted synergistic and significant antitumor effects in vivo on HSC-2 tumor xenografts, and induced apoptosis in tumor cells. Furthermore, this combination therapy led to decreased MVD and cell proliferative abilities, as well as increased apoptosis in residual tumors. The present findings suggested that the bevacizumab plus S-1 combination therapy may exert antitumor effects in high VEGF-A-expressing OSCC cells.

Effects of lentinan alone and in combination with fluoropyrimidine anticancer agent on growth of human oral squamous cell carcinoma in vitro and in vivo.

Chemotherapy has shown little antitumor activity against advanced oral squamous cell carcinoma (OSCC) patients. Therefore, there is an urgent need to develop more effective therapeutic methods for patients with advanced OSCC. Lentinan, beta-(1-->3)-D-glucan, an extract from the edible mushroom, Lentinus edodes, has been reported to show direct antitumor effects and various immunomodulatory effects. S-1 is an oral antineoplastic agent that can induce apoptosis in various types of cancer cells, including OSCC. Hence, combined treatment of cancer cells with Lentinan and S-1 might exert dramatic antitumor effects on OSCC cells. In this study, the response of human OSCC cells to Lentinan alone and in combination with S-1 was examined using nude mouse xenograft models. S-1 (6.9 mg/kg/day, 7 times/week) was administered orally and Lentinan (0.1 mg/kg/day, 2 times/week) was injected into peritumoral tissue for three weeks. Apoptotic cells were detected by a TUNEL method. The gene expression level of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and orotate phosphoribosyl transferase (OPRT) was determined using microdissection and RT-PCR, and their protein levels were determined using ELISA. Combined therapy of Lentinan and S-1 markedly exerted antitumor effects on human OSCC xenografts and significantly induced apoptotic cells in tumors treated with Lentinan plus S-1. Microdissection and RT-PCR revealed that the expression of TS and DPD mRNA was down-regulated and that expression of OPRT mRNA was up-regulated in tumors administered the combined treatment. Moreover, ELISA indicated that the protein levels of TS and DPD were down-regulated, and that OPRT was up-regulated in tumors treated with the combined therapy. During the experimental period, no loss of body weight was observed in mice treated with the combined therapy. These findings demonstrate that the combination of Lentinan and S-1 is effective against OSCC and has the potential of being a new therapeutic tool for future treatment of these tumors.

Cepharanthine inhibits angiogenesis and tumorigenicity of human oral squamous cell carcinoma cells by suppressing expression of vascular endothelial growth factor and interleukin-8.

Cepharanthine is a biscoclaurine alkaloid extracted from Stephania cepharantha Hayata, which is widely used for the treatment of many acute and chronic diseases, and can exert antitumor effects on several human cancer cell lines. However, little is known about the detailed mechanisms of the antitumor activity of Cepharanthine. In the present study, we determined whether Cepharanthine could suppress angiogenesis and growth of human oral squamous cell carcinoma (OSCC) cells in vitro and in vivo. Cepharanthine significantly inhibited expression of two major pro-angiogenic molecules, vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8), in cultured cells and in cells implanted into the subcutaneous tissue of nude mice. Also, Cepharanthine inhibited the nuclear factor-kappaB (NF-kappaB) activity in human OSCC cells in vitro and in vivo. The decreased expression of VEGF and IL-8 correlated with decreased tumor cell growth and decreased vascularization in vitro and in vivo. These findings suggest that Cepharanthine can suppress angiogenesis and growth of OSCC cells by inhibiting expression of VEGF and IL-8 involved in the blockade of NF-kappaB activity.

Effects of cepharanthine alone and in combination with fluoropyrimidine anticancer agent, S-1, on tumor growth of human oral squamous cell carcinoma xenografts in nude mice.

BACKGROUND: Chemotherapy has shown little antitumor activity against advanced oral squamous cell carcinoma (OSCC) patients. Therefore, there is an urgent need to develop more effective therapeutic methods for patients with advanced OSCC. Cepharanthine is a biscoclaurine alkaloid extracted from Stephania cepharantha Hayata, which is widely used for the treatment of many acute and chronic diseases, and can exert antitumor effects on several human cancer cells. S-1 is a new oral antineoplastic agent that can induce apoptosis in various types of cancer cells, including OSCC. Hence combined treatment of cancer cells with cepharanthine and S-1 might exert dramatic antitumor effects on OSCC cells. MATERIALS AND METHODS: In this study, the response of human OSCC cells to cepharanthine alone and in combination with S-1 was examined using nude mouse xenograft models. S-1 (10 mg/kg/day, 5 times/week) was administered orally and cepharanthine (20 mg/kg, 5 times/week) was injected into peritumoral tissue for three weeks. Apoptotic cells were detected by a TUNEL method. The protein expression of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyl transferase (OPRT) were assessed using immunohistochemistry; their gene expression was determined using microdissection and RT-PCR, and their protein levels using ELISA. RESULTS: Combined therapy of cepharanthine and S-1 exerted antitumor effects on human OSCC xenografts markedly and significantly induced apoptotic cells in tumors treated with cepharanthine plus S-1. Immunohistochemistry showed that the expressions of TS and DPD were down-regulated, and that OPRT expression was up-regulated in tumors treated with cepharanthine plus S-1. In the same way, microdissection and RT-PCR revealed that the expression of TS and DPD mRNA was down-regulated and that expression of OPRT mRNA was up-regulated in tumors administered the combined treatment. Moreover, ELISA indicated that the protein levels of TS and DPD were down-regulated, and that OPRT was up-regulated in tumors treated with the combined therapy. During the experimental period, no loss of body weight was observed in mice treated with the combined therapy. CONCLUSION: These findings demonstrate that the combination of cepharanthine and S-1 is effective against OSCC and has the potential of being a new therapeutic tool for future treatment of these tumors.

Effects of tumor necrosis factor-related apoptosis-inducing ligand alone and in combination with fluoropyrimidine anticancer agent, S-1, on tumor growth of human oral squamous cell carcinoma xenografts in nude mice.

BACKGROUND: Chemotherapy has shown little antitumor activity against advanced oral squamous cell carcinoma (OSCC) patients. Therefore, there is an urgent need to develop more effective therapeutic methods for patients with advanced OSCC. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor ligand family that selectively induces apoptosis of cancer cells. S-1 is a new oral antineoplastic agent that can induce apoptosis in various types of cancer cells, including OSCC. Hence, combined treatment of cancer cells with TRAIL and S-1 might exert dramatic antitumor effects on OSCC cells. MATERIALS AND METHODS: In this study, the response of human OSCC cells to TRAIL alone and in combination with S-1 was examined using nude mouse xenograft models. S-1 (10 mg/kg/day, 5 times/week) was administered orally and TRAIL (1 mg/kg, 5 times/week) was injected into peritumoral tissue for three weeks. Apoptotic cells were detected by a TUNEL method. The protein expression of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyl transferase (OPRT) were assessed using immunohistochemistry; their gene expression was determined using microdissection and RT-PCR, and their protein levels using ELISA. RESULTS: Combined therapy of TRAIL and S-1 exerted antitumor effects on human OSCC xenografts markedly and significantly induced apoptotic cells in tumors treated with TRAIL plus S-1. Immunohistochemistry showed that the expressions of TS and DPD were down-regulated, and that OPRT expression was up-regulated in tumors treated with TRAIL plus S-1. In the same way, microdissection and RT-PCR revealed that the expression of TS and DPD mRNA was down-regulated and that expression of OPRT mRNA was up-regulated in tumors administered the combined treatment. Moreover, ELISA indicated that the protein levels of TS and DPD were down-regulated, and that OPRT was up-regulated in tumors treated with the combined therapy. During the experimental period, no loss of body weight was observed in mice treated with the combined therapy. CONCLUSION: These findings demonstrate that the combination of TRAIL and S-1 is effective against OSCC and has the potential of being a new therapeutic tool for future treatment of these tumors.

High expression of S-phase kinase-associated protein 2 (Skp2) is a strong prognostic marker in oral squamous cell carcinoma patients treated by UFT in combination with radiation.

Low expression of p27(Kip1) is associated with disease progression and an unfavorable outcome in several malignancies including oral squamous cell carcinoma (SCC). In addition, p27(Kip1) protein is thought to be degraded by Skp2 (S-phase kinase-associated protein 2). The purpose of this study was to examine whether Skp2 expression can be a useful prognostic factor in oral SCC patients treated by UFT in combination with radiation. The Skp2 expression was investigated by immunohistochemistry in biopsy samples from 102 oral SCC patients, who were treated by UFT in combination with radiation. Associations of each expression with the clinicopathological characteristics and patient survival were also analyzed. A significant association was found between Skp2 expression and tumor size (p = 0.0462), cervical lymph node metastasis (p = 0.0209), therapeutic effect (p = 0.0490) and patient outcome (p = 0.0002). The 5-year survival rates of Skp2 high and low expression tumors were 40.5% and 78.5%, respectively, and this difference was significant (p = 0.0001) by log-rank test. Multivariate analysis revealed that reduced term of survival was related to high levels of Skp2 expression (p = 0.0001). These results suggest that Skp2 may be a useful prognostic factor in oral SCC patients treated by UFT in combination with radiation.

Down-regulation of S-phase kinase associated protein 2 (Skp2) induces apoptosis in oral cancer cells.

S-phase kinase associated protein 2 (Skp2) is a member of an F-box family of substrate-recognition subunits of SCF ubiquitin-protein ligase complexes that has been implicated in the ubiquitin-mediated degradation of several key regulators of mammalian G1 progression, including the cyclin-dependent kinase inhibitor p27Kip1, a dosage-dependent tumor suppressor protein. The anti-sense effect was confirmed in two cell lines of oral cancer cells that also exhibited over-expression of the Skp2 protein. In this study, we examined the mechanism responsible for anti-sense-mediated growth inhibition of oral cancer cells in vitro and in vivo. Skp2-anti-sense treatment induced apoptosis characterized by an increase in the early apoptosis, fragmentation of nuclei and activation of caspase-3, -8 and -9. Moreover, the growth of xenograft tumors was markedly suppressed by Skp2-anti-sense treatment. Furthermore, histological specimen revealed apoptotic cell death was increased in Skp2-anti-sense treated tumors. Our results suggest that down-regulation of Skp2 appears to induce apoptosis in oral cancer cells, targeting this molecule could represent a promising new therapeutic approach for this type of cancer.