Masami Miyamoto

Concurrent infiltration by CD8+ T cells and CD4+ T cells is a favourable prognostic factor in non-small-cell lung carcinoma.

The purpose of this study was to clarify the relationship between the number of tumour-infiltrating T lymphocytes and the clinicopathological features and clinical outcome in patients with non-small-cell lung cancer (NSCLC). Tissue specimens from 109 patients who underwent surgical resection for NSCLC were immunohistochemically analysed for CD4 and CD8 expression. Patients were classified into two groups according to whether their tumours exhibited a ‘high’ or ‘low’ level of CD8+ or CD4+ lymphocyte infiltration. Although the level of infiltration by CD8+ T cells alone had no prognostic significance, the survival rate for patients with both ‘high’ CD8+ and ‘high’ CD4+ T-cell infiltration was significantly higher than that for the other groups (log-rank test, P=0.006). Multivariate analysis indicated that concomitant high CD8+ and high CD4+ T-cell infiltration was an independent favourable prognostic factor (P=0.0092). In conclusion, the presence of high levels of both CD8+ T cells and CD4+ T cells is a significant indicator of a better prognosis for patients with NSCLC, and cooperation between these cell populations may allow a significantly more potent antitumour response than either population alone.

Impact of caveolin-1 expression on prognosis of pancreatic ductal adenocarcinoma.

Caveolin-1 is a major component of caveolae and plays a regulatory role in several signalling pathways. Caveolin-1 was recently identified as a metastasis-related gene in prostate cancer. The clinical effects of caveolin-1 expression in pancreatic carcinoma, however, remain unknown. In this study, we have investigated the relationship between caveolin-1 expression and the clinicopathologic variables and clinical outcome in 79 patients with pancreatic adenocarcinoma undergoing surgical resection. Caveolin-1 expression was determined by immunohistochemistry, using a polyclonal anti-caveolin-1 antibody. Patients were divided into two groups based on the extent of caveolin-1 expression: a negative expression group (immunoreactivity in less than 50% of cells) and a positive expression group. Positive caveolin-1 immunostaining was detected in 32 cases (40.5% of total), while non-neoplastic ductal epithelium showed little or no staining. Positive caveolin-1 expression was correlated with tumour diameter (P=0.0079), histopathologic grade (P=0.0272) and poor prognosis (P=0.0008). Upon multivariate analysis with Coxs proportional hazards model, positive caveolin-1 expression was shown to be an independent negative predictor for survival (P=0.0358). These results suggest that caveolin-1 overexpression is associated with tumour progression, thereby indicating a poor prognosis for certain patients undergoing surgical resection for pancreatic carcinoma.

Overexpression of hypoxia-inducible-factor 1alpha(HIF-1alpha) in oesophageal squamous cell carcinoma correlates with lymph node metastasis and pathologic stage.

The purpose of this study is to investigate the clinical and histopathologic significance of hypoxia-inducible-factor 1α (HIF-1α) expression in oesophageal squamous cell carcinoma. One hundred and thirty surgically resected specimens of OSCC were immunohistochemically assessed for HIF-1α expression with monoclonal antibody. High HIF-1α immunostaining was detected in 40 specimens. The percentage of high HIF-1α expression cases increased with tumour stage according to pTNM system. High HIF-1α expression correlated with pTNM stage, depth of tumour invasion, lymph node metastasis, distant metastasis, lymphatic invasion and positive surgical margin. The overall survival rate was worse in patients with high HIF-1α pattern than in patients with low-expression pattern. Univariate analyses identified high HIF-1α positivity, depth of tumour invasion, lymph node metastasis, distant metastasis, lymphatic invasion, and a positive surgical margin as risk factors. Multivariate analyses indicated that depth of tumour invasion, lymph node metastasis and positive surgical margin, but not HIF-1α, were independent prognostic factors. Survival in patients with a high HIF-1α expression was significantly worse than in those with low expression in patient treated with adjuvant therapy.

Clinical significance of immune cell infiltration within gallbladder cancer

To investigate the pathophysiological significance of infiltrating antitumour immune cells, we evaluated the quantity of immune cell intratumoral infiltration in 110 surgically resected gallbladder specimens by immunohistochemistry. We examined 45 cases of gallbladder cancer and 65 cases of benign gallbladder diseases for CD4+ T cells, CD8+ T cells, natural killer cells (NKCs), and dendritic cells (DCs). High levels of CD4+ T cell, CD8+ T cell, NKC, and DC infiltration were recognised in 51.1% (23 out of 45), 37.8% (17 out of 45), 33.3% (15 out of 45), and 48.9% (22 out of 45) of cancer specimens, respectively. High numbers of infiltrating CD4+ and CD8+ T cells correlated with decreasing tumour invasion, and high numbers of infiltrating DCs correlated with decreasing lymph-node tumour metastasis. Furthermore, increased infiltration of CD4+ and CD8+ T cells and DCs exhibited a significant correlation with prolonged survival. NKC infiltration, however, did not correlate with any of the clinicopathological factors examined. Additionally, high levels of infiltration were not identified in specimens from benign diseases, consistent with the cancer-specific activity of CD4+ and CD8+ T cells and DCs. In this study, we demonstrate that CD4+ and CD8+ tumour-infiltrating lymphocyte and DCs, but not NKCs, are important factors in the accurate prognosis of survival after surgical removal of gallbladder adenocarcinoma.

Fusion of HIV-1 Tat protein transduction domain to poly-lysine as a new DNA delivery tool

Effective gene therapy depends on the efficient transfer of therapeutic genes to target cells. None of the current technologies, however, satisfy all of the requirements necessary for gene therapy, because the plasma and nuclear membranes of mammalian cells are tight barriers against gene transfer using synthetic delivery systems. The protein transduction domain (PTD) of human immunodeficiency virus type 1 (HIV-1) Tat protein greatly facilitates protein transfer via membrane destabilisation. We synthesised polylysine peptides containing Tat PTD (TAT-pK), or other sequences, and investigated their potential as agents for gene transfer. The synthesised polypeptide TAT-pK retains DNA binding function and mediates delivery of a reporter gene to cultured cells. RGD motif binds with low affinity to alpha integrins which induce cell activation. Two control polypeptides, GGG-pK and RGD-pK, were synthesised and tested, but their gene transfer abilities were weaker than those of TAT-pK. TAT-pK-mediated gene transfer was enhanced in the presence of chloroquine or ammonium chloride, to a greater extent than that of cationic lipid-mediated gene transfer in most cancer cell lines tested. These data suggest that TAT-pK may be a potent candidate delivery vehicle that promotes gene transfer, dependent on the endocytic pathway. We conclude that the TAT-pK/DNA complex is useful as a minimal unit to package therapeutic genes and to transduce them into mammalian cells.

RCAS1 as a tumour progression marker: an independent negative prognostic factor in gallbladder cancer

Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) induces apoptosis in immune cells bearing the RCAS1 receptor. We sought to determine RCAS1 involvement in the origin and progression of gallbladder cancer, and also implications of RCAS1 for patient survival. RCAS1 expression was examined immunohistochemically in 110 surgically resected gallbladder specimens. The gallbladders represented 20 cases of cholecystitis with no associated pancreaticobiliary maljunction; 23 cases of cholecystitis with pancreaticobiliary maljunction; 14 cases of adenomyomatosis; 7 adenomas; and 46 cancers. High expression of RCAS1 (immunoreactivity in over 25% of cells) was observed in 32 of the 46 cancers (70%), but not in other diseases, including pre-cancerous conditions. RCAS1 immunoreactivity was associated with depth of tumour invasion (P = 0.0180), lymph node metastasis (P = 0.0033), lymphatic involvement (P = 0.0104), venous involvement (P = 0.0224), perineural involvement (P = 0.0351) and stage by the tumour, nodes and metastases (TNM) classification (P = 0.0026). Thus, RCAS1 expression may be a relatively late event in gallbladder carcinogenesis possibly promoting tumour progression. Cox regression multivariate analysis demonstrated RCAS1 positivity to be an independent negative predictor for survival (P = 0.0337; risk ratio, 12.690; 95% confidence interval, 1.216–132.423). High expression of RCAS1 significantly correlated with tumour progression and predicted poor outcome in gallbladder cancer.

Role of human cytochrome P450 (CYP) in the metabolic activation of nitrosamine derivatives: application of genetically engineered Salmonella expressing human CYP.

The role of human cytochrome P450 (CYP) in the metabolic activation of tobacco-related N-nitrosamines was examined by Salmonella mutation test using a series of genetically engineered Salmonella typhimurium YG7108 strains each co-expressing a form of CYP (CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, and CYP3A5) together with human NADPH–cytochrome P450 reductase. Seven tobacco-related N-nitrosamines such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N-nitrosodiethylamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosonornicotine, N-nitrosoanabasine, and N-nitrosoanatabine were used. The CYP2A6 was found to be responsible for the mutagenic activation of essentially all tobacco-related N-nitrosamines examined. On the basis of the evidence, genetic polymorphism of the CYP2A6 gene appeared to be one of the factors determining cancer susceptibility caused by smoking. Previously, we found the whole deletion of the CYP2A6 gene (CYP2A6*4C) as a type of genetic polymorphism in Japanese. We hypothesized that individuals possessing the gene homozygous for CYP2A6*4C were incapable of activating tobacco-related N-nitrosamines and showed lower susceptibility to lung cancer induced by tobacco smoke. Thus, the relationship between the CYP2A6*4C and the susceptibility to the lung cancer was evaluated. The frequency of the CYP2A6*4C was significantly lower in the lung cancer patients than healthy volunteers, suggesting that the subjects carrying the CYP2A6*4C alleles are resistant to carcinogenesis caused by N-nitrosamines because of the poor metabolic activation capacity. Taking these results into account, CYP2A6 is an enzyme enhancing lung cancer risk.

Infiltrating regulatory T cell numbers is not a factor to predict patient's survival in oesophageal squamous cell carcinoma

CD4/8 status has been previously reported to be a critical factor in the prognosis of oesophageal squamous cell carcinoma (OSCC). In the current study, we investigated the effect of regulatory T cells (Treg; Foxp3+ lymphocytes) on the status of CD4+ and CD8+ T cells in 122 patients with OSCC. Immunohistochemical analysis of Treg was performed using an antibody against Foxp3. The survival rate for low Foxp3 patients was significantly lower than for high Foxp3 patients (P=0.0028 by log-rank test), but Foxp3 status did not significantly correlate with prognosis in CD4/8(+/+) patients or CD4/8(+/−) or (−/+) patients (P=0.5185 and 0.8479, respectively, by log-rank test). We also found that Foxp3 status correlated with CD4/8 status (P=0.0002 by χ2 test) and that the variance of CD8/CD4 ratio in patients with low Foxp3 was larger than in patients with high Foxp3 (P<0.0001 by F-test). Thus, the results do not support the idea that Treg suppress anti-tumour immunity in patients with OSCC. Rather, the CD8/CD4 ratio and CD4/8 status appear to be critical factors in anti-tumour immunity. Furthermore, Treg numbers correlate with both the CD8/CD4 ratio and the CD4/8 status, suggesting that Treg number is not a factor to predict patients survival in OSCC.

DARPP-32 expression arises after a phase of dysplasia in oesophageal squamous cell carcinoma

This is the first report to correlate DARPP-32 immunoreactivity (dopamine and cAMP-regulated phosphoprotein, Mr 32 000) to clinicopathological status in human cancer. DARPP-32 is recognised as a neuronal protein. A recent study demonstrated that DARPP-32, and a truncated isoform t-DARPP, are overexpressed in gastric carcinoma during the process of carcinogenesis. The biological function of DARPP-32, however, is still unclear. The purpose of this study was to clarify the roles of DARPP-32 and t-DARPP in oesophageal squamous cell carcinoma (OSCC). Initially, we investigated DARPP-32 and t-DARPP expression in OSCC cell lines by Reverse transcription–polymerase chain reaction and Western blot. DARPP-32 expression was observed in four out of seven (57.1%) cell lines, but t-DARPP expression was not observed in any cell lines. In oesophageal tissue sample, DARPP-32 expression was observed in four out of seven (57.1%) tumour tissues, while t-DARPP was not observed in any tissues. Subsequently, DARPP expression was assessed by immunohistochemistry, using a polyclonal antibody, in tissue sections from 122 patients with primary OSCC. DARPP immunoreactivity was not observed in any normal oesophageal mucous membranes. On the other hand, positive DARPP immunostaining was detected in 37 patients (30.3%) and correlated inversely with pathologic stage (P=0.0284), pT (P=0.0438), pN (P=0.0303) and tumour size (P=0.012). The overall survival rate was worse in patients with DARPP-negative tumours than in patients with DARPP-positive tumours (P=0.0453). Interestingly, DARPP expression was observed in only one out of 45 cases of dysplasia. These observations suggest that DARPP-32 (rather than t-DARPP) expression arises after a phase of dysplasia in OSCC, and that tumours expressing DARPP-32 progress less rapidly than DARPP-32-negative tumours.

Transcriptional targeting of adenovirus vectors with the squamous cell carcinoma-specific antigen-2 promoter for selective apoptosis induction in lung cancer.

Squamous cell carcinoma antigens SCCA1 and SCCA2 are highly homologous serine proteinase inhibitors which have been widely utilized as serological markers for squamous cell cancers, but it has recently been demonstrated that only SCCA2 is truly specific for certain forms of lung cancer. Using a construct containing the 5′-flanking region of the SCCA2 gene between −460 and +0 bp and the luciferase reporter gene, SCCA2 promoter activity was detected in SCCA2-producing SCC cell lines (LK-2, LC-1), but not in SCCA2-nonproducing lung adenocarcinoma cell lines (A549, ABC-1, and RERF-LC-MS) or normal cells (WI-38, SAEC, and NHEK-Adult). Infection with a recombinant adenovirus vector, Ad-SCCA2-DsRed, resulted in cell-specific expression of the SCCA2 promoter-driven DsRed marker gene only in LK-2 and LC-1 cells. The same strategy was used for SCCA2-driven expression of a proapoptotic gene, (KLAKLAK)2, which can cause mitochondrial disruption by triggering mitochondrial permeabilization and swelling, resulting in the release of cytochrome c and induction of apoptosis. Infection with Ad-SCCA2-KLAKLAK2 specifically reduced the growth of the two human lung SCC cell lines compared to the SCCA2 nonproducing cell lines both in vitro and in vivo, suggesting that the SCCA2 promoter had a tumor-specific effect. These results suggest that transduction of SCCA2 promoter-controlled suicide genes by adenoviral vectors can confer transcriptionally targeted cytotoxicity in SCCA2-producing lung SCC cells, and represents a novel strategy for gene transfer specifically targeted to SCC in the lung.