Kenji Mitsudo

Selective hyperthermia using magnetoliposomes to target cervical lymph node metastasis in a rabbit tongue tumor model

The effect of hyperthermia on cervical lymph node metastasis of VX7 tongue cancer in female Japanese white rabbits was investigated. Magnetoliposomes (MLs) with a neutral surface charge and a size of 94.1 nm were used as heating mediators. MLs were injected into the tongue 20 days after tumor transplantation, and we examined whether they reached the metastatic deep cervical lymph node. The highest magnetite concentration 24 h after ML injection was detected in the lymph node, followed by tongue, spleen, blood, and liver. Rabbits were separated into three groups: group I as the control; group II with ML injection alone; and group III with ML injection and hyperthermia 24 h after ML injection, generated by applying an alternating magnetic field (118 kHz, 384 Oe) to the neck region. The hyperthermic effect was evaluated in terms of the percentage of necrosis in proportion to the metastatic tumor and the apoptotic index (AI), defined as the ratio of TUNEL‐positive cells. The temperature of lymph nodes in group III reached over 44°C. The mean area of necrosis in group III was 58.0%, which was significantly higher than that in group I (19.6%) or group II (20.4%). The AI in group III was 22.9%, significantly higher than in group I (1.67%) or II (1.42%). The difference between group I and II was not statistically significant. Group III tumor sites around MLs showed necrosis or apoptosis‐positive cells induced by hyperthermia. These results indicate that MLs injected into the tongue can target cervical lymph node metastases and accumulate there at concentrations sufficient to generate therapeutically effective temperatures.

Up-regulation of CD109 expression is associated with carcinogenesis of the squamous epithelium of the oral cavity

CD109 is a glycosylphosphatidylinositol (GPI)–anchored glycoprotein whose expression is up‐regulated in squamous cell carcinomas (SCCs) of the lung, esophagus, and uterus. The purpose of this study was to evaluate CD109 expression in oral tumors, including premalignant lesions, and to assess the clinical application of CD109 in oral cancer. CD109 expression in oral normal and tumor tissues from 124 patients was examined by immunohistochemical staining with anti‐CD109 antibody, and significant relations between clinical features and CD109 expression were statistically assessed. We found that high levels of CD109 expression were frequently detected in SCCs and premalignant lesions of the oral cavity, but not in normal squamous epithelia. The CD109 expression level was higher in well‐differentiated SCCs than in poorly differentiated SCCs. Furthermore, premalignant lesions highly expressing CD109 showed higher risk to progress to SCCs. Oral SCC cell lines overexpressing CD109 exhibited accelerated cell growth in vitro compared with control cell lines. In addition, overexpression of CD109 impaired the transforming growth factor (TGF)–β1‐mediated suppression of cell growth. These findings suggest that CD109 plays a role in the development of oral cancers, and is a useful prognostic marker to predict malignant transformation of premalignant lesions. (Cancer Sci 2008; 99: 1916–1923)

Overexpression of caveolin-1 in a human melanoma cell line results in dispersion of ganglioside GD3 from lipid rafts and alteration of leading edges, leading to attenuation of malignant properties.

Caveolin‐1 is a component of lipid rafts, and is considered to be a tumor suppressor molecule. However, the mechanisms by which caveolin‐1 functions in cancer cells are not well understood. We generated caveolin‐1 transfectant cells (Cav‐1+ cells) using a human melanoma cell line (SK‐MEL‐28) and investigated the effects of caveolin‐1 overexpression on the GD3‐mediated malignant properties of melanomas. Cav‐1+ cells had decreased cell growth and motility, and reduced phosphorylation levels of p130Cas and paxillin relative to controls. In floatation analysis, although GD3 was mainly localized in glycolipid‐enriched microdomain (GEM)/rafts in control cells, it was dispersed from GEM/rafts in Cav‐1+ cells. Correspondingly, GD3 in Cav‐1+ cells stained uniformly throughout the membrane, whereas control cells showed partial staining of the membrane, probably at the leading edge. p130Cas and paxillin were stained in the leading edges and colocalized with GD3 in the control cells. In contrast, these molecules were diffusely stained and no definite leading edges were detected in Cav‐1+ cells. These results suggest that caveolin‐1 regulates GD3‐mediated malignant signals by altering GD3 distribution and leading edge formation. These results reveal one of the mechanisms by which caveolin‐1 curtails the malignant properties of tumor cells. (Cancer Sci 2007; 98: 512–520)

Retrograde superselective intra-arterial chemotherapy and daily concurrent radiotherapy for stage III and IV oral cancer: Analysis of therapeutic results in 112 cases

PURPOSE To evaluate the therapeutic results and rate of organ preservation in patients with stage III or IV oral cancer treated with retrograde superselective intra-arterial chemotherapy and daily concurrent radiotherapy. MATERIALS AND METHODS One hundred and twelve patients with stage III and IV oral squamous cell carcinoma underwent intra-arterial chemoradiotherapy. Catheterization from the superficial temporal and occipital arteries was performed. Treatment consisted of superselective intra-arterial chemotherapy (docetaxel, total 60mg/m(2), cisplatin, total 150mg/m(2)) and daily concurrent radiotherapy (total of 60Gy) for 6 weeks. RESULTS The median follow-up for all patients was 46.2 months (range, 10-76 months). After intra-arterial chemoradiotherapy, primary site complete response was achieved in 98 (87.5%) of 112 cases. Five-year survival and local control rates were 71.3% and 79.3%, respectively. Grade 3 or 4 toxicities included mucositis in 92.0%, neutropenia in 30.4%, dermatitis in 28.6%, anemia in 26.8%, and thrombocytopenia in 7.1% of patients. Grade 3 toxicities included dysphagia in 72.3%, nausea/vomiting in 21.4%, fever in 8.0%, and renal failure in 0.9% of patients. CONCLUSION Retrograde superselective intra-arterial chemotherapy and daily concurrent radiotherapy for stage III and IV oral cancer provided good overall survival and local control.

Improvement of transduction efficiency of recombinant adenovirus vector conjugated with cationic liposome for human oral squamous cell carcinoma cell lines

Adenovirus (Ad) vectors are commonly used in gene therapy trials because of their efficiency in gene transfer. However, their use is limited by immune responses that reduce transgene expression and decrease the efficiency of repeated vector administration. In this study, the efficacy of gene transduction and the tumor-cell killing effect on four human oral (SAS, HSC-2, HSC-3, HSC-4) and one murine squamous cell carcinoma cell (SCC-7, a kind gift of Dr. M. Hiraoka, Kyoto University) lines in vitro with Ad vector conjugated with catioic liposome (Ad/SUV) was evaluated. Ad/SUV resulted in two to five-fold over higher transduction efficiency in four human and one murine cell lines in vitro than Ad vector alone. The optimal Ad-SUV ratio was determined as 10(6) pfu of Ad vector with 1 micromol SUV. Ad/SUV showed more tumor-cell killing effect than Ad vector alone. Furthermore, the shielding effects of Ad vector with Ad/SUV from neutralizing antibody were evaluated. We also found that Ad/SUV is less susceptible to inactivation by neutralizing antibodies in vitro. The efficacy of gene transduction with Ad vector was blocked more than 70% with neutralizing serum, while Ad/SUV retained approximately 50% of the control activity in vitro. On the basis of these results, the anti-tumor effect with suicide gene therapy using Ad/SUV in vivo was evaluated. Three injections of Ad/SUV showed the inhibition of tumor growth compared with control in vivo. Our results suggested that an enhanced anti-tumor effect on human oral squamous cell carcinoma would be obtained with repeated administrations of Ad/SUV.

M2-polarized macrophages contribute to neovasculogenesis, leading to relapse of oral cancer following radiation

Despite the fact that radiation is one of the standard therapies in the treatment of patients with oral cancer, tumours can recur even in the early stages of the disease, negatively impacting prognosis and quality of life. We previously found that CD11b+ bone marrow-derived cells (BMDCs) were recruited into human glioblastoma multiforme (GBM), leading to re-organization of the vasculature and tumour regrowth. However, it is not yet known how these cells contribute to tumour vascularization. In the present study, we investigated the role of infiltrating CD11b+ myeloid cells in the vascularization and recurrence of oral squamous cell carcinoma (OSCC). In a xenograft mouse model, local irradiation caused vascular damage and hypoxia in the tumour and increased infiltration of CD11b+ myeloid cells. These infiltrating cells showed characteristics of M2 macrophages (M2Mφs) and are associated with the promotion of vascularization. M2Mφs promoted tumour progression in recurrence after irradiation compared to non-irradiated tumours. In addition, we found that CD11b+ myeloid cells, as well as CD206+ M2Mφs, are increased during recurrence after radiotherapy in human OSCC specimens. Our findings may lead to the development of potential clinical biomarkers or treatment targets in irradiated OSCC patients.

Simultaneous hyperthermia-chemotherapy with controlled drug delivery using single-drug nanoparticles

We previously investigated the utility of μ-oxo N,N′- bis(salicylidene)ethylenediamine iron (Fe(Salen)) nanoparticles as a new anti-cancer agent for magnet-guided delivery with anti-cancer activity. Fe(Salen) nanoparticles should rapidly heat up in an alternating magnetic field (AMF), and we hypothesized that these single-drug nanoparticles would be effective for combined hyperthermia-chemotherapy. Conventional hyperthermic particles are usually made of iron oxide, and thus cannot exhibit anti-cancer activity in the absence of an AMF. We found that Fe(Salen) nanoparticles induced apoptosis in cultured cancer cells, and that AMF exposure enhanced the apoptotic effect. Therefore, we evaluated the combined three-fold strategy, i.e., chemotherapy with Fe(Salen) nanoparticles, magnetically guided delivery of the nanoparticles to the tumor, and AMF-induced heating of the nanoparticles to induce local hyperthermia, in a rabbit model of tongue cancer. Intravenous administration of Fe(Salen) nanoparticles per se inhibited tumor growth before the other two modalities were applied. This inhibition was enhanced when a magnet was used to accumulate Fe(Salen) nanoparticles at the tongue. When an AMF was further applied (magnet-guided chemotherapy plus hyperthermia), the tumor masses were dramatically reduced. These results indicate that our strategy of combined hyperthermia-chemotherapy using Fe(Salen) nanoparticles specifically delivered with magnetic guidance represents a powerful new approach for cancer treatment.

Prognostic Evaluation of Preoperative Thermochemoradiotherapy for N3 Cervical Lymph Node Metastases of Oral Cancer

Objective: The purpose of this study was to evaluate the clinical efficacy, histopathological efficacy, and response to preoperative thermochemoradiotherapy for N3 cervical lymph node metastases of oral cancer. Methods: Preoperative thermochemoradiotherapy was performed in 8 patients with oral cancer and N3 cervical lymph node metastasis. These patients underwent four-weekly sessions of hyperthermia, combined with radiotherapy (40 Gy) as well as chemotherapy with cisplatin (CDDP; 100 mg/m2), all prior to surgery. Radical neck dissection was performed 4 weeks after completion of preoperative thermochemoradiotherapy. Results: The preoperative treatment of cervical lymph node metastases yielded a partial response in 6 patients, while 2 patients demonstrated no change. Histopathologically, grade III was detected in 1, grade IIb in 4 and grade IIa in 3 patients after surgery, according to the criteria of Shimosato. The follow-up period ranged from 13 to 64 months (mean 34). Of the 8 patients, 2 died (1 of lymph node metastasis and 1 had metastasis to a distant site), and 6 patients were alive at the last follow-up, with the longest postoperative disease-free survival being 63 months. The 5-year cumulative survival rate was 70.0%. Conclusion: These results indicate that preoperative thermochemoradiotherapy is a promising modality for patients with N3 cervical lymph node metastasis of oral cancer.

Secure Surgical Method for Catheter Placement via the Occipital Artery to Achieve Retrograde Superselective Intra-Arterial Chemotherapy for Advanced Oral Cancer: Alternative to Approach via the Superficial Temporal Artery.

We describe secure surgical method for catheter placement using ultrasonic scalpel via the occipital artery to achieve retrograde superselective intra-arterial chemotherapy for advanced oral cancer, as alternative to approach via the superficial temporal artery.

Opposite impact of NKG2D genotype by lifestyle exposure to risk of aerodigestive tract cancer among Japanese

It was reported that there are 2 haplotypes in natural killer complex (NKC) region. One of them could be divided by NKG2D polymorphism into 2 haplotype alleles (high and low natural killer (NK) cell activity) and were associated with overall cancer risks. However, its impact on a specific cancer is unclear. Therefore, by a case‐control study, we analyzed the association between NKG2D genotype and aerodigestive tract cancer risk. Subjects were 502 aerodigestive tract cancer patients (276 with head and neck, 226 with esophageal) and 1,004 sex‐age matched noncancer controls. Exposures to 2 lifestyle factors, smoking and drinking, were evaluated by a self‐administered questionnaire. The genotype of NKG2D was determined by the TaqMan method, and its impact was assessed by multivariable logistic regression models. Association strength was measured by the odds ratio (OR) and its confidence intervals (CI). An overall analysis revealed no statistically significant association between NKG2D genotype and the risk of aerodigestive tract cancer. However, we found protective effects of G allele among never smokers (OR 0.35; 95% CI 0.15–0.84) and never drinkers (0.42; 0.19–0.94). In contrary, increased risks were observed for G allele among heavy smokers (5.92; 3.23–10.85) and heavy drinkers (4.13; 2.29–7.47). Interactions between NKG2D genotype and lifestyle exposure were statistically significant (interaction p = 0.001 for smoking, 0.005 for drinking). The same trends were observed in both sexes, and in head and neck cancer and esophageal cancer independently. These results suggest an opposite impact of NKG2D genotype by lifestyle exposure to the risk of aerodigestive tract cancer among a Japanese population.