Yuichiro Kuratomi

Effects of the angiotensin-I converting enzyme inhibitor perindopril on tumor growth and angiogenesis in head and neck squamous cell carcinoma cells

Purpose Recently, it has been reported that angiotensin-I converting enzyme (ACE) inhibitors have anticancer activity. In particular, the ACE inhibitor, perindopril, significantly inhibits tumor growth and angiogenesis in hepatocellular carcinoma cells along with suppression of the VEGF level. However, the mechanisms of suppression of the VEGF level are still unclear, and there are no previous reports on this subject related to head and neck squamous cell carcinoma (HNSCC). In some previous studies, angiotensin II, which is produced from angiotensin I by ACE, directly stimulates VEGF expression.Methods In the present study, we focused upon angiotensin II, and investigated the effect of perindopril on VEGF expression, angiogenesis, and tumor development of HNSCC with in vitro and in vivo studies.Results In the in vitro cell proliferation assays, there was no significant difference between the perindopril-treated group and the control group. However, the perindoprilat-treated group showed a significant reduction in mRNA expression of VEGF and inhibited the induction activity of the VEGF promoter in comparison to the control group. Perindoprilat treatment also significantly suppressed angiotensin II production in vitro. In the in vivo studies, perindopril had a significant inhibitory effect on tumor growth, and reduced blood vessel formation surrounding the tumors.Conclusions Our findings suggest that perindopril has no direct cytotoxicity against tumor cells, but has a potential to inhibit tumor growth due to suppression of VEGF-induced angiogenesis in vivo. Angiotensin II might have an important role in carcinogenesis, and the antiangiogenic activity of perindopril is at least partly mediated by angiotensin II inhibition. The ACE inhibitor perindopril has clinical potential as a useful antitumor agent.

The Roles of JNK1 and Stat3 in the Response of Head and Neck Cancer Cell Lines to Combined Treatment with All trans‐retinoic Acid and 5‐Fluorouracil

We have used a combination of vitamin A (all‐trans‐retinyl palmitate), 5‐fluorouracil (5‐FU) and radiation to treat human head and neck squamous cell carcinoma (HNSCC). This chemoradiother‐ apy is called “FAR therapy” In this study we examined the effects of all‐trans‐retinoic acid (ATRA), the active metabolite of vitamin A, and ATRA plus 5‐FU on two HNSCC cell lines (YCU‐ N861 and YCU‐H891) to gain insight into the molecular mechanisms of FAR therapy. ATRA at 1 μM (the order of concentration found in HNSCC tumors treated with FAR therapy) inhibited cell proliferation and caused Gl cell cycle arrest in both cell lines. This was associated with a decrease in cyclin D1, an increase in p27Kipl and a reduction in the hyperphosphorylated form of retinoblastoma protein (pRB). With YCU‐N861 cells, ATRA also caused a decrease in Bcl‐2 and Bcl‐XL and an increase in Bax. Both ATRA and 5‐FU activated c‐Jun N‐terminal kinase (JNK) 1 and the combination of both agents resulted in additive or synergistic activation of JNK1, and also enhanced the induction of apoptosis. The YCU‐H891 cells, in which the epidermal growth factor receptor (EGFR)‐signal transducer and activator of transcription 3 (Stat3) pathway is constitutively activated, were more resistant to treatments with ATRA, 5‐FU and the combination of both agents than YCU‐N861 cells. A dominant negative Stat3 construct strongly enhanced the cellular sensitivity of this cell line to 5‐FU but not to ATRA. In addition there is evidence that activation of Stat3 is associated with cellular resistance to radiation in HNSCC. Therefore, the addition to FAR therapy of agents that inhibit activation of the Stat3 pathway may enhance the clinical response of patients with HNSCC to FAR therapy.

Establishment of tumor cell lines from a patient with head and neck cancer and their different sensitivities to anti-cancer agents

The authors established five cell lines from a human head and neck tumor. The five cell lines (HC‐2, HC‐3, HC‐4, HC‐7, and HC‐9) exhibited different sensitivities to Adriamycin, cisplatin, bleomycin, 5‐fluorouracil, vincristine, and daunomycin. The D50 was 200 ng/ml Adriamycin (doxorubicin) for HC‐7 and 45 ng/ml for HC‐2. At the inception of long‐term culture (11 months) in the absence of any drug, the sensitivity to Adriamycin of HC‐7‐5 (subcloned from HC‐7) was 3.4 times greater than that of HC‐2‐6 (subcloned from HC‐2); by 11 months, it decreased to 1.6 times that of HC‐2‐6. The cytocidal action of Adriamycin on HC‐2‐6 and HC‐7‐5 was potentiated when Adriamycin was combined with verapamil or cepharanthine. Cepharanthine also potentiated daunomycin and vincristine (VCR) against HC‐2‐6 and HC‐7‐5 cells, and it almost completely overcame drug‐resistance to daunomycin and vincristine in HC‐7‐5/VCR, a multidrug‐resistant variant isolated after long exposure to vincristine of HC‐7‐5 cells in culture. The cellular accumulation of [3H]‐daunomycin by HC‐7‐5 cells was about 70% that of HC‐2‐6 cells. By Northern blot analysis, using a multidrug‐resistance gene (mdr‐1) probe, neither HC‐2‐6 nor HC‐7‐5 expressed the mdr‐1 gene, but HC‐7‐5/VCR or other multidrug‐resistant variants showed active expression of the mdr‐1 gene. Differential sensitivities among the five cell lines to 5‐fluorouracil, cisplatinum, and bleomycin appear to be mediated through other mechanism beside the mdr‐1 gene.

Decreased CD44H expression in early-stage tongue carcinoma associates with late nodal metastases following interstitial brachytherapy

Late nodal metastases is a critical factor that worsens the prognosis of T1/T2N0 tongue cancer treated by interstitial brachytherapy. If we could better predict the patients at high risk for late nodal metastases developing before treatment, more appropriate choices of treatment could be selected. In recent studies of colon cancer, prostate cancer, and laryngeal cancer, CD44H has been postulated to be a metastasis suppressor.

“FAR” chemoradiotherapy improves laryngeal preservation rates in patients with T2N0 glottic carcinoma†

The appropriate treatment approach for patients with T2N0 laryngeal cancer remains highly controversial. Because radiotherapy alone is associated with a high risk of local recurrence, we have developed a triple combination treatment approach consisting of 5‐fluorouracil (250 mg/day, i.v.), vitamin A (50,000 unit/day, i.m.) and external radiation (2.0 Gy/day), which we have termed “FAR therapy.”

SCCA1 expression in T-lymphocytes peripheral to cancer cells is associated with the elevation of serum SCC antigen in squamous cell carcinoma of the tongue

Squamous cell carcinoma (SCC) antigen has been used for the management of SCC arising in various cites including head and neck region. However, the true mechanism of the elevation of this protein in the serum of patients with SCC is still unknown. SCC antigen belongs to the superfamily of serine protease inhibitors. Recently, molecular studies show that serum SCC antigen is transcribed by two nearly identical genes (SCCA1 and SCCA2), and is mainly produced by SCCA1. The objective of this study is to clarify the mechanism of the elevation of SCC antigen in oral tongue SCC patients and to identify cells histologically, which are responsible for serum SCC antigen production. In this study, we examined SCCA1 expression in a series of four head and neck SCC (HNSCC) cell lines, and found that all expressed equal to low SCCA1 protein as compared with the normal human oral keratinocyte. Using the double immunohistochemical technique to examine the expression pattern of SCCA1 in 86 cases of oral tongue squamous cell carcinoma, SCCA1 immunostaining was observed in the cytoplasm of cancer cells and T-lymphocytes peripheral to cancer cells. We also compared the clinicopathological features including serum SCC antigen level of the oral tongue SCC cases with the immunohistochemical SCCA1 expression pattern, and found that elevated serum SCC antigen level was significantly correlated with SCCA1 expression not in cancer cells, but in T-lymphocytes peripheral to cancer cells. These results suggest that T-lymphocytes peripheral to cancer cells may be responsible for serum SCC antigen production in HNSCC patients.

Thioridazine enhances lysosomal accumulation of epidermal growth factor and toxicity of conjugates of epidermal growth factor with Pseudomonas exotoxin

Thioridazine, a phenothiazine calmodulin inhibitor, aggravated the cytotoxic effect of a conjugate (EGF-PE) of epidermal growth factor (EGF) coupled with Pseudomonas exotoxin against cultured HeLa cells. Other phenothiazine calmodulin inhibitors, trifluoperazine and chlorpromazine, also intensified the cytotoxic effect of EGF-PE, whereas N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W7) had no such effect. By using iodinated epidermal growth factor ( [125I]EGF), the effect of thioridazine on intracellular transport of EGF was examined. The release of radioactivity associated with [125I]EGF into medium was slow in the presence of thioridazine. The Percoll gradient centrifugation pattern showed that thioridazine delayed both the appearance of [125I]EGF in lysosomes and the disappearance of [125I]EGF from the lysosomes. The pH value in lysosomes was 5.28 in thioridazine-treated HeLa cells, while that in untreated cells was 5.15. Thioridazine was found to inhibit lysosomal enzyme activities of cathepsin B and acid phosphatase, but not beta-hexosaminidase when cell extracts were treated with the drug. Electron microscopy showed an increased number of electron-dense bodies, possibly autophagosomes/lysosomes in HeLa cells grown for 48 h with 3 micrograms/ml thioridazine. The potentiating action of EGF-PE by thioridazine is discussed in relation to the altered lysosomal function in treated cells.

Histological changes of the pharynx and larynx in rats with chronic acid reflux esophagitis.

Conclusions: The histological changes of the pharynx and the larynx associated with surgically induced chronic acid reflux esophagitis were observed in rats. Chronic inflammatory change due to gastric acid reflux was found microscopically in the pharynx and larynx. This indicated that inflammatory changes due to gastric acid reflux are associated with the pathogenesis of laryngopharyngeal reflux disease (LPRD). Objective: To clarify the pathological mechanism of LPRD by studying the histological changes of the pharynx and the larynx in rats with chronic acid reflux esophagitis. Materials and methods: An experimental rat model of chronic acid reflux esophagitis was created surgically. The pharynx, larynx, trachea, lung, and esophagus of these rats were observed histologically every 2 weeks until 20 weeks after the operation. Results: At 8 weeks after the operation, mucosal thickening and inflammatory cell infiltration were observed in the hypopharynx of the rat model. Moreover, chronic inflammation with proliferation of fibroblasts, deposition of collagen fibers, and proliferation and dilatation of the capillaries were found as time progressed. However, little macroscopic change was observed in the hypopharyngeal mucosa. In addition, at 16 weeks post-operation, inflammatory cell infiltration was identified in the nerve cells around the thoracic esophagus, the arytenoid region, and the lung.

Follicular dendritic cell sarcoma of the neck; a case report and literature review

Follicular dendritic cell (FDC) sarcomas, also known as dendritic reticulum cell tumors, are uncommon neoplasms arising from antigen-presenting cells in B-lymphofollicles of nodal and extra-nodal sites. It is considered as an intermediate grade malignancy since it has significant recurrent and metastatic potential. We report a case of FDC sarcoma arising in the neck. A 56-year-old female presented with a left neck tumor. Neck dissection was performed. Microscopically, the tumor showed spindle-shaped stromal cells with large oval and polygonal nuclei. Immunohistologically, the cells were positive for CD21 and CD35, consistent with FDC sarcomas. Adjuvant chemotherapy of cyclophosphamide/doxorubicin/vincristine/prednisone (CHOP) was given. Literature review provides the current information for the diagnosis and treatment of this unusual tumor.

Effects of a novel NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), on growth, apoptosis, gene expression, and chemosensitivity in head and neck squamous cell carcinoma cell lines

Recent studies provide evidence that the constitutive activation of nuclear factor‐kappa B, NF‐κB plays a critical role in enhancing the growth of several types of malignancies, including head and neck squamous cell carcinoma (HNSCC).