Mariko Kawakami

Evidence that IL-13R alpha2 chain in human glioma cells is responsible for the antitumor activity mediated by receptor-directed cytotoxin therapy.

The interleukin-13 receptor α2 (IL-13Rα2) chain is a primary IL-13 binding and internalization component of the IL-13R system. Previous studies have shown that human brain tumors, including glioblastoma multiforme (GBM), overexpress IL-13Rα2 chain, while normal brain cells do not express this protein or express very low levels of it. To target IL-13R on brain tumor cells, the authors have developed an IL-13R-directed cytotoxin termed IL13-PE38QQR to induce specific cancer cell killing. To investigate the role of IL-13Rα2 chain in GBM, cells were treated with antisense oligonucleotide or siRNA to IL-13Rα2 chain, and cellular IL-13 binding and sensitivity to IL-13 cytotoxin were assessed. IL-13Rα2 gene interference in GBM cells showed decreased ligand binding, and consequently IL-13 cytotoxin exhibited less cytotoxicity to these cells. The authors next evaluated the antitumor activity of IL-13 cytotoxin in native IL-13R-expressing tumors and after gene transfer of IL-13Rα2 by injecting plasmid in U87MG tumors subcutaneously implanted in nude mice. These mice were then treated with IL-13 cytotoxin. Mean tumor size in mice receiving intraperitoneal or intratumoral IL-13 cytotoxin was significantly smaller in control tumors; however, tumor sizes were much smaller in IL-13Rα2-transfected tumors. Furthermore, convection-enhanced delivery of IL-13Rα2 cDNA in intracranially established U87MG glioma followed by IL-13 cytotoxin administration by the same route mediated tumor regression and prolonged survival of animals by 164% compared with control. These results indicate that IL-13Rα2 chain in GBM cells is essential for IL-13 cytotoxin-induced cytotoxicity and that IL-13Rα2 chain plays a critical biologic role in IL-13 cytotoxin-mediated therapy for GBM.

Antitumor effects of ZD6474 on head and neck squamous cell carcinoma.

Angiogenesis is required for tumor growth and metastasis and, therefore, represents a target for cancer treatment. While many factors have been implicated in promoting angiogenesis, vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis. ZD6474 is a potent VEGF receptor-2 (VEGFR-2) tyrosine kinase inhibitor which also has activity against the epidermal growth factor receptor (EGFR) tyrosine kinase. The purpose of this study was to investigate the sensitivity of head and neck squamous cell carcinoma (HNSCC) cell lines to ZD6474, and to evaluate its antitumor efficacy on HNSCC xenografts. This is the first demonstration of antitumor effects of ZD6474 on HNSCC. In vitro ZD6474 displayed antiproliferative effects on HNSCC cells and inhibition of VEGFR-2 and EGFR pathways. In vivo ZD6474 displayed antitumor activity, induced apoptosis and antiangiogenic activity on nude mice bearing an established xenograft of YCU-H891 cells. These results suggest that ZD6474 has the potential to inhibit two key pathways in tumor growth via inhibition of VEGF-dependent tumor angiogenesis and via inhibition of EGFR-dependent tumor cell proliferation.

Expression and Targeting of Interleukin-4 Receptor for Primary and Advanced Ovarian Cancer Therapy

Because the most characteristic property of ovarian cancer is i.p. spread, the majority of patients are diagnosed at an advanced stage, leading to limited availability of options for curative therapies. With an intent to identify targeted therapeutic approaches, we have observed that approximately 60% of 21 ovarian cancer tissue samples express a high density of interleukin-4 receptor (IL-4R), whereas normal ovarian tissues tested (n = 7) expressed no or low levels of IL-4R. To target IL-4R, we have developed IL-4 cytotoxin, in which circular-permuted IL-4 is fused to a mutated form of Pseudomonas exotoxin. This cytotoxin is specifically and highly cytotoxic to PA-1, IGROV-1, and SK-OV3 ovarian carcinoma cell lines in vitro. In addition, it shows remarkable antitumor activities against established s.c. ovarian tumors in immunodeficient animals. i.p. administration of IL-4 cytotoxin in mice with orthotopically implanted ovarian tumors caused regression of established tumors and prevented these animals from tumor metastasis. Continuous i.p. infusion of IL-4 cytotoxin prolonged survival of tumor-bearing mice even with bulky disease. These results indicate that IL-4R-targeted cytotoxin may be a useful agent for the management of patients with ovarian cancer, and further studies need to be done to evaluate its safety, tolerability, and efficacy.

Characterization of a Novel Human Tumor Antigen Interleukin-13 Receptor α2 Chain

The interleukin (IL)-13 receptor alpha2 (IL-13Ralpha2) chain is a primary binding and internalization subunit for a Th2-derived immune regulatory cytokine, IL-13. Although extremely high levels of IL-13Ralpha2 chain are expressed on a variety of human tumor cells and specimens, its precise role in tumor immunology has not been defined. To investigate the role of IL-13Ralpha2 in tumor immunity, we used D5 melanoma cells stably transfected with the human IL-13Ralpha2 gene (D5alpha2) to assess the effect of an IL-13Ralpha2 DNA vaccine in immunocompetent animals. Prophylactic immunization of mice with the IL-13Ralpha2 DNA vaccine resulted in protection against D5alpha2 tumor development. In vivo depletion experiments in C57BL/6 and RAG-2 knockout mice indicated that both T and B cells, but not natural killer cells, were required for the tumor protection. In addition, antibody induced by the IL-13Ralpha2 DNA vaccine showed a modest but significant inhibitory effect on D5alpha2 cells in vitro, suggesting that the antibody is biologically functional. The IL-13Ralpha2 DNA vaccine also exhibited antitumor activity against established D5alpha2 tumors in mice. Histologic analysis of regressing tumors identified infiltration of CD4+ and CD8+ T cells and the expression of CXCL9 chemokine in tumors. Taken together, our results identify the human IL-13Ralpha2 chain as a novel tumor rejection antigen.

The efficacy and safety of concurrent chemoradiotherapy for maxillary sinus squamous cell carcinoma patients

OBJECTIVE Combined treatment modality, e.g., definitive surgery followed by radiotherapy (RT) and definitive RT with concurrent chemotherapy, has been applied for advanced maxillary sinus squamous cell carcinoma (MSSCC) patients to obtain a better survival with organ preservation in Japan. METHODS The outcome of 40 patients with MSSCC between 1991 and 2007 in our institute was analyzed retrospectively. There were 36 males and 4 females, the average age being 59.5 years (ranging from 34 to 81 years). The median follow-up time was 66.1 months. All the patients had received a combined treatment consisting of definitive surgery, RT, and intra-arterial or systemic chemotherapy. The chemotherapeutic regimen was different depending on the performance status and/or complications of the patients. Since 1998, concurrent chemoradiotherapy with cisplatin, 5-fluorouracil, methotrexate and leucovorin regimen (CCRT-PFML) instead of neo-adjuvant chemotherapy has been applied. RESULTS The overall 5-year survival rate was 59.2%, the 5-year disease-specific survival rate was 71.7%, and the 5-year organ preservation survival rate was 42.4%. In the group receiving CCRT-PFML, the overall 5-year survival rate was 60.0%, the 5-year disease-specific survival rate was 76.0%, and the 5-year organ preservation survival rate was 60.3%. CONCLUSION CCRT-PFML for advanced MSSCC patients is feasible to preserve the organs without reducing the survival rate.

Decrease of creatinine clearance rate with aging in patients with head and neck cancer in Japan

BackgroundWe aimed to clarify the reason for the lower dosage of cis-platinum (CDDP) in patients with head and neck cancer in Japan compared with that in other countries, by evaluating renal function.MethodsWe studied 375 patients with head and neck cancer who had been hospitalized from January 1998 to October 2005, to evaluate and treat the disease. The creatinine clearance rate (Ccr) was calculated at least three times before beginning the treatments, and the average Ccr was estimated to evaluate the renal function.ResultsThe Ccr decreased with aging, and the percentages of patients with Ccr lower than 65 ml/min per 1.73 m2 were 27.1% of patients in their fifties, 36.8% in their sixties, 62.3% in their seventies, and 87.5% in their eighties. There was no correlation between renal function and the Japanese lifestyle (i.e., diet. water consumption).ConclusionThe renal function of Japanese decreases rapidly with aging, whereas that of Americans is maintained for longer periods. The poor renal function of Japanese is one of the causes of the need to reduce the dosage of or avoid the administration of CDDP in cancer patients.

Antitumor effects of IDN5109 on head and neck squamous cell carcinoma

Taxanes, a new class of antitumor drugs, are effective against a large number of human tumors, although there are problems with drug resistance. The novel taxane, IDN5109, is characterized by its high tolerability, antitumor efficacy, ability to overcome multidrug resistance, and oral bioavailabilty. We investigated the cellular response of IDN5109 to head and neck squamous cell carcinoma (HNSCC), and compared the antitumor activity of IDN5109 with that of paclitaxel. This is the first demonstration of antitumor effects of IDN5109 on HNSCC. In in vitro experiments, IDN5109 showed antiproliferative effects against HNSCC cell lines. After treatment with IDN5109, Bcl-2 and Bcl-XL were down-regulated, Bax was up-regulated, and caspase-3 was activated. After treatment with IDN5109, concentrations of both VEGF and IL-8 in the culture supernatant of HNSCC cells decreased. In in vivo experiments, the oral administration of IDN5109 showed antitumor effects against HNSCC tumor xenografts. Immunohistochemistry showed that IDN5109 inhibited tumor angiogenesis and induced apoptosis in HNSCC cells, producing a decreased blood vessel density and increased apoptosis index. On the basis of these results, IDN5109 is useful as a chemotherapeutic agent against HNSCC.

Nitric Oxide Accelerates Interleukin-13 Cytotoxin-Mediated Regression in Head and Neck Cancer Animal Model

Receptors for interleukin-13 (IL-13R) are overexpressed on several types of solid cancers including gliobastoma, renal cell carcinoma, AIDS Kaposi’s sarcoma, and head and neck cancer. Recombinant fusion proteins IL-13 cytotoxin (IL13-PE38QQR or IL13-PE38) have been developed to directly target IL-13R-expressing cancer cells. Although it has been found that IL-13 cytotoxin has a direct potent antitumor activity in vivo in nude mice models of human cancers, the involvement of indirect antitumor effecter molecules such as nitric oxide (NO) is unknown. To address this issue, we assessed the effect of NO inhibiter Nω-monomethyl-l-arginine on IL-13 cytotoxin-mediated cytotoxicity and NO2/NO3 production in HN12 head and neck cancer cells. In addition, antitumor effects and NO levels in HN12 and KCCT873 head and neck tumors xenografted s.c. in nude mice when treated with IL-13 cytotoxin were evaluated by tumor measurement, Western blot, and immunohistochemistry analyses. Pretreatment of animals with Nω-monomethyl-l-arginine significantly decreased the NO levels and IL-13 cytotoxin-mediated antitumor effects. In addition, depletion of macrophages, known to produce NO, also decreased antitumor activity of IL-13 cytotoxin. Based on these studies, we concluded that NO accelerates antitumor effect of IL-13 cytotoxin on head and neck tumor cells. Because IL-13 cytotoxin is currently being tested in the clinic for the treatment of patients with recurrent glioblastoma maltiforme, our current findings suggest maintaining macrophage and NO-producing cellular function for optimal therapeutic effect of this targeted agent.