Takahiro Wakasaki

T Cell Leukemia/Lymphoma 1 and Galectin-1 Regulate Survival/Cell Death Pathways in Human Naive and IgM+ Memory B Cells through Altering Balances in Bcl-2 Family Proteins

BCR signaling plays a critical role in purging the self-reactive repertoire, or in rendering it anergic to establish self-tolerance in the periphery. Differences in self-reactivity between human naive and IgM+ memory B cells may reflect distinct mechanisms by which BCR signaling dictates their survival and death. Here we demonstrate that BCR stimulation protected naive B cells from apoptosis with induction of prosurvival Bcl-2 family proteins, Bcl-xL and Mcl-1, whereas it rather accelerated apoptosis of IgM+ memory B cells by inducing proapoptotic BH3-only protein Bim. We found that BCR-mediated PI3K activation induced the expression of Mcl-1, whereas it inhibited Bim expression in B cells. Phosphorylation of Akt, a downstream molecule of PI3K, was more sustained in naive than IgM+ memory B cells. Abundant expression of T cell leukemia/lymphoma 1 (Tcl1), an Akt coactivator, was found in naive B cells, and enforced expression of Tcl1 induced a high level of Mcl-1 expression, resulting in prolonged B cell survival. In contrast, Galectin-1 (Gal-1) was abundantly expressed in IgM+ memory B cells, and inhibited Akt phosphorylation, leading to Bim up-regulation. Enforced expression of Gal-1 induced accelerated apoptosis in B cells. These results suggest that a unique set of molecules, Tcl1 and Gal-1, defines distinct BCR signaling cascades, dictating survival and death of human naive and IgM+ memory B cells.

Chemoprevention of head and neck cancer by green tea extract: EGCG-the role of EGFR signaling and "lipid raft"

Over the past decade dose-intensified chemo-radiotherapy or molecular targeted therapy has been introduced into the treatments of head and neck squamous cell carcinoma (HNSCC) to improve the outcomes of this dismal disease. However, these strategies have revealed only limited efficacy so far. Moreover, the frequent occurrences of second primary tumor further worsen the prognosis of patients. In this context, early detection and chemoprevention appear to be a realistic and effective method to improve the prognosis as well as quality of life in patients with HNSCC. In this short paper, we discuss the potential of green tea extract, (-)-epigallocatechin-3-galate (EGCG) in HNSCC chemoprevention, focusing on two aspects that are provided recently: (1) evidence of clinical efficacy and (2) unique biological effects on “lipid raft” that emerged as an important platform of numerous biophysical functions, for example, receptor tyrosin kinases (RTKs) signalings including epidermal growth factor receptor (EGFR), which play critical roles in HNSCC carcinogenesis.

Correlations between thymidylate synthase expression and chemosensitivity to 5-fluorouracil, cell proliferation and clinical outcome in head and neck squamous cell carcinoma

Background: 5-Fluorouracil (5-FU) is a widely used drug in head and neck squamous cell carcinoma (HNSCC). Thymidylate synthase (TS), which is the target enzyme of 5-FU, has been demonstrated to be a key regulatory enzyme. In this study, we examined whether TS expression is correlated with chemosensitivity to 5-FU, cell proliferation and clinical outcome in HNSCC. Methods: An antisense TS cDNA was constitutively expressed in the HNSCC cell line. The effects of TS expression on in vitro cell growth and 5-FU cytotoxicity were examined. We also evaluated the association between TS expression and cell proliferation in surgical specimens, and prognosis in HNSCC patients. Results: Antisense TS transfection increases the cytotoxicity of 5-FU and inhibits cell proliferation in HNSCC cellsin vitro. Immunohistochemical expression of TS may have prognostic value in patients with HNSCC. Conclusions: These results indicate that TS expression plays an important role in the sensitivity of HNSCC to 5-FU chemotherapy.

Somatic evolution of head and neck cancer – Biological robustness and latent vulnerability

Despite recent advancements in multidisciplinary treatments, the overall survival and quality of life of patients with advanced head and neck squamous cell carcinoma (HNSCC) have not improved significantly over the past decade. Molecular targeted therapies, which have been addressed and advanced by the concept of “oncogene addiction”, have demonstrated only limited successes so far. To explore a novel clue for clinically effective targeted therapies, we analyzed the molecular circuitry of HNSCC through the lens that HNSCC is an evolving system. In the trajectory of this somatic evolution, HNSCC acquires biological robustness under a variety of selective pressures including genetic, epigenetic, micro‐environmental and metabolic stressors, which well explains the major mechanism of “escaping from oncogene addiction”. On the other hand, this systemic view appears to instruct us approaches to target latent vulnerability of HNSCC that is masked behind the plasticity and evolvability of this complex adaptive system.

Relative level of thymidylate synthase mRNA expression in primary tumors and normal tissues predicts survival of patients with oral tongue squamous cell carcinoma

Thymidylate synthase (TS) is a major target of 5-fluorouracil (5-FU) and dihydropyrimidine dehydrogenase (DPD) is a rate-limiting enzyme in the degradation of 5-FU. There are no studies investigating the comparison of TS and DPD mRNA expressions in oral tongue SCC (OSCC) and nontumor tissues obtained from the same patients. In addition, increased interest has been focused on the biological roles of TS and DPD as the independent prognostic factors as well as responsive determinants for cancer patients with 5-FU based therapy. We determined the expression levels of TS and DPD in tumor (T) and nontumor squamous epithelial tissues (N) of OSCC using real-time reverse transcription-polymerase chain reaction and evaluated whether the T/N ratio would correlate with clinicopathological factors. The mRNA expressions of TS and DPD were significantly higher in tumor areas than in nontumor areas. No correlation was found between the T/N ratio of each mRNA expression and gender, clinical stage, T classification, N classification or differentiation. The T/N ratio of TS in patients that died of disease was significantly higher than in patients with free of disease, whereas there were no relationships between The T/N ratio of DPD and disease status. Clinical follow-up data showed shorter overall survival periods for cases with high T/N ratio of TS than for cases with low T/N ratio of TS with the statistically significant. Our study showed that TS but not DPD seems to have prognostic value in OSCC. These findings suggest that the assessment of TS activity may be useful both in the management and in the treatment of OSCC.

Thymidylate synthase expression as a predictor of clinical response to 5-fluorouracil-based chemoradiotherapy in patients with maxillary sinus squamous cell carcinoma

OBJECTIVE The aim of this study was to evaluate the immunohistochemical TS expression in patients with maxillary sinus SCC. METHODS The value of immunohistochemical TS expression as a predictive indicator for 5-FU efficacy was retrospectively examined in 47 patients with maxillary sinus SCC. RESULTS Of the 47 patients, 29 (62%) showed complete response for 5-FU based chemoradiotherapy. Seventeen of 19 (89%) TS low cases showed a complete response, whereas 12 of 28 (43%) TS high cases showed complete response for 5-FU based chemoradiotherapy. Low TS patients had significantly better response rates compared with high TS patients. CONCLUSION These findings suggest that TS expression affects the chemotherapeutic effect of 5-FU in patients with maxillary sinus SCC and the assessment of TS expression level might be useful both in the management and in the treatment of maxillary sinus SCC.

The clinical value of serum squamous cell carcinoma antigens 1 and 2 in head and neck squamous cell carcinoma

OBJECTIVE The usefulness of pretreatment measurement of SCC antigen in patients with head and neck SCC is still controversial. Our aim of this study was to evaluate the clinical usefulness of serum SCC antigen, SCCA1 and SCCA2 in the management of patients with head and neck SCC. METHODS Serum samples for the analysis of SCCA1, SCCA2 and SCC antigen were taken from head and neck SCC patients before treatment. Serum SCC antigen was assayed with a solid phase immunoradiometric assay. The SCCA1 and SCCA2 protein level was determined by a sandwich ELISA. RESULTS Fifty-two of 96 cases (54%) showed evaluated serum SCC antigen levels above the upper limit. The serum SCCA2 level was significantly higher in the head and neck SCC patients than in control group, whereas there were no significant differences in the serum SCCA1 level between head and neck SCC patients and control group. 72% of head and neck SCC patients demonstrated SCCA2 levels higher than 0.15, whereas 68% of the control subjects had SCCA2 levels less than 0.15. CONCLUSION The serum SCCA2 levels were increased during the progression of cancer and might be a useful tool for the management of head and neck SCC.

Utility of chemoradioselection for the optimization of treatment intensity in advanced hypopharyngeal and laryngeal carcinoma

Definitive concomitant chemoradiotherapy (CRT) with high-dose cis-platinum (CDDP) is a current standard protocol for advanced laryngeal and hypopharyngeal cancer sparing surgery for salvage. However, this modality is associated with limited feasibility and frequent sever toxicities. In the present study, a ‘chemoradioselection’ protocol with minimal toxicity was developed using initial response to CRT as a biomarker for patient selection. Between 2000, March and 2012, September 123 patients with stage III (44), IV (79) laryngeal (64) and hypopharyngeal carcinoma (59) excluding T4 cases were enrolled to this protocol. Two cycles of split (15 mg/m2 ×5 days, 2000–2008) or bolus (80 mg/m2, 2009-present) CDDP was concurrently administered. Tumor responses were evaluated after 40 Gy of CRT and 64 responders (chemoradioselected, CRS) received further CRT up to 70 Gy, while radical surgery was recommended for the 59 non-responders (N-CRS), and 34 underwent surgery (N-CRS-ope). The remaining 25 patients who refused surgery (N-CRS-refu) were treated with continuous CRT. The 5-year overall survival (OS) and disease-specific survival (DSS) were 67, and 77%, respectively. The CRS demonstrated favorable 5-year OS (73%) and laryngo-esophageal dysfunction-free survival (LEDFS, 69%) rates. In contrast, the N-CRS-refu showed significantly lower 5-year OS (47%) compared with CRS (73%) and N-CRS-ope (70%) (P=0.0193), and significantly lower 5-year LEDFS (20%) compared with the CRS (69%) (P<0.0001). On multivariate analyses, including T, N, primary site and planned treatment (CRS + N-CRS-ope) or not (N-CRS-refu), unplanned treatment alone showed a significant correlation with poor OS [hazard ratio (HR), 2.584; 95% confidence interval (CI), 1.313–4.354; P=0.007). Chemoradioselection reflects the biological aggressiveness of each tumor, and is able to segregate patients for functional laryngeal preservation with moderate intensity CRT (150–160 mg/m2 of CDDP) from those who would be better treated with surgery. This strategy may be useful for the optimization of the therapeutic intensity.

Tracheo-innominate artery fistula after mediastinal tracheostomy: A case report

A 61-year-old man visited our hospital with a chief compliant of pharyngeal pain. After extent-of-disease checkup examinations (endoscopy, CT, PET and MRI), a diagnosis of cervical esophageal cancer (cT4N2M0) was made. He was treated with 70.2 Gy of CRT with FP (5-FU 700mg/m2 + CDDP 70mg/m2) and CR was achieved. However, his tumor recurred 5 months after CRT and salvage TPLE with the creation of a mediastinal tracheostoma was performed. Although we inserted a pectoralis major muscle flap around the trachea to protect the great vessels, massive bleeding from the brachiocephalic artery occurred 1 month after surgery. Emergency placement of an endovascular stent graft worked well and relatively long-term hemostasis was achieved.

Posterior Reversible Encephalopathy Syndrome During Combined Modality Therapy for Head and Neck Squamous Cell Carcinoma.

Objectives: Posterior reversible encephalopathy syndrome (PRES) is a rare and acute disease with central nervous system symptoms. Without appropriate therapy, patients may exhibit a poor prognosis. PRES should be recognized as a possible problem during therapy for head and neck squamous cell carcinoma (HNSCC). Methods: A 56-year-old female developed PRES during combined modality therapy for HNSCC. On the fourth day after surgery and following chemoradiotherapy, PRES developed with a sudden visual disorder, followed by headache located at the back of the head and convulsions accompanied by impaired consciousness. We diagnosed PRES based on the clinical manifestations and magnetic resonance imaging data. Results: The patient recovered from PRES by appropriate treatment. Conclusion: This is the first case report of PRES developed during treatment for HNSCC. Masked by other cerebrovascular disorders, more cases of PRES could exist than usually expected; therefore, we should consider PRES as a differential diagnosis for central nervous system disorders developing during high-intensity therapy.