Tooru Shiratori

Tyrosine Phosphorylation Controls Internalization of CTLA-4 by Regulating Its Interaction with Clathrin-Associated Adaptor Complex AP-2

CTLA-4 is a costimulation receptor that binds to the same ligands, CD80 and CD86, as CD28 with high affinity and is transiently expressed on the cell surface of activated T cells. CTLA-4 delivers an inhibitory signal through association of a phosphotyrosine-containing motif in the cytoplasmic domain with Syp tyrosine phosphatase. We now demonstrate that CTLA-4 interacts with the mu2 subunit of the plasma membrane-associated adaptor complex, AP-2, through the same motif involved in the interaction with Syp, except that the interaction with mu2 requires unphosphorylated tyrosine. The interaction with mu2 likely induces rapid internalization of CTLA-4 from the cell surface. Our results suggest that the phosphorylation state of a single tyrosine residue determines whether CTLA-4 delivers a negative signal or is internalized.

Resistance of Fc receptor- deficient mice to fatal glomerulonephritis.

Immune complex-mediated inflammation is a common mechanism of various autoimmune diseases. Glomerulonephritis (GN) is one of these diseases, and the main mechanism of the induction of GN has been unclear. We examined the contribution of Fc receptors in the induction of nephrotoxic GN by establishing and analyzing mice deficient in the Fc receptor gamma chain (FcRgamma). Whereas all wild-type mice died from severe glomerulonephritis with hypernitremia by administration of anti-glomerular basement membrane (GBM) antibodies, all FcRgamma-deficient mice survived. Histologically, wild-type mice showed glomerular hypercellularity and thrombotic changes, whereas the renal tissue in FcRgamma-deficient mice was almost intact. Deposition of anti-GBM antibody as well as complement components in the GBM were equally observed in both wild-type and knockout mice. These results demonstrate that the triggering of this type of glomerulonephritis is completely dependent on FcR+ cells.

Impact of the Number and Extent of Positive Lymph Nodes in 200 Patients with Thoracic Esophageal Squamous Cell Carcinoma after Three-field Lymph Node Dissection

BackgroundSubtotal esophagectomy with three-field lymph node dissection (3FLD) has been reported to improve survival in patients with thoracic esophageal squamous cell carcinoma (SCC). The purpose of this study was to evaluate the prognostic impact of the extent and number of positive lymph nodes for long-term survival of patients who underwent 3FLD.MethodsFrom January 1983 to December 2002, a total of 200 patients with thoracic esophageal SCC underwent 3FLD without any neoadjuvant therapy. The prognostic impact of the extent and number of positive lymph nodes was evaluated by both univariate and multivariate analysis.ResultsThe extent of positive nodes associated with a 5-year survival were as follows: none, 69%; one-field, 50%; two-field, 29%; and three-field, 11%. The number of positive nodes associated with 5-year survival were as follows: single node, 65%; two-nodes, 51%; and more than three-nodes, 20%. Among patients with cervical lymphatic spreading, patients with upper tumors showed significantly better survival than patients with lower tumors (P = 0.036). Multivariate analysis indicated that number of positive nodes and the abdominal node status were independent prognostic factors among lymph node status.ConclusionsTogether, number and extent of positive lymph nodes can be considered an independent predictor of a high risk of recurrence. Although cervical lymphatic spreading was risk factor for worse survival, patients with upper tumors may have survival benefit after cervical lymph node dissection.

Phase I/II adenoviral p53 gene therapy for chemoradiation resistant advanced esophageal squamous cell carcinoma

We investigated the feasibility, safety, biological activity and therapeutic efficacy of adenovirus‐mediated p53 gene transfer in patients with chemoradiation resistant advanced esophageal carcinoma. Eligible patients were not surgical candidates and had measurable, advanced squamous cell carcinoma of the esophagus that was resistant to chemoradiation therapy. On a 28‐day cycle, intratumoral injections of Ad5CMV‐p53 (INGN 201; ADVEXIN®) were administered on days 1 and 3 at four dose levels (10 × 1011 particles to 25 × 1011 particles) and treated for up to five cycles. Ten patients received a total of 26 cycles with no dose‐limiting toxicity. Administration of multiple courses was feasible and well‐tolerated. Local tumor responses revealed stable disease in nine cases and progressive disease in one case. The overall responses were stable in six and progressive in four cases. Using polymerase chain reaction (PCR) analyses, gene transfer and p53 specific transgene expression were detected in tumor biopsy tissue from all patients. mRNA levels of p53, p21 and MDM2 increased in all but one case. Three patients showed absence of disease upon repeat biopsies. Substantial improvement in swallowing was observed in one patient with stenotic lesions. Intratumoral injection of Ad5CMV‐p53 is safe, feasible and biologically active when administered in multiple doses to patients with esophageal cancer. Observations from this study indicate that this treatment results in local antitumor effects in chemoradiation resistant esophageal squamous cell carcinoma. (Cancer Sci 2006; 97)

Prognostic significance of CYFRA 21-1 in patients with esophageal squamous cell carcinoma

BACKGROUND CYFRA 21-1 has been reported as a useful tumor marker for esophageal carcinoma, but little information was reported about the clinicopathologic importance of CYFRA 21-1. The aim of this study was to analyze the clinicopathologic and prognostic significance of preoperative CYFRA 21-1 in patients with esophageal squamous cell carcinoma. STUDY DESIGN The CYFRA 21-1 levels were measured before surgery by enzyme-linked immunosorbent assays in 157 patients with primary esophageal squamous cell carcinomas using 3.5 ng/mL as the upper limit of normal. All patients underwent radical surgical procedures without any preoperative therapy. The association between the clinicopathologic factors assessed and the CYFRA 21-1 level was determined. The CYFRA 21-1 values were monitored after surgery in 45 available patients. The prognostic values were determined by multivariate analysis using Coxs proportional hazards model. RESULTS Thirty-one of the 157 patients (19.7%) had high CYFRA 21-1 levels (> or =3.5 ng/mL). CYFRA 21-1 levels were significantly increased in patients with large tumors (> or =40 mm, p = 0.009), deep tumors (T2-T4, p = 0.003), and node-positive tumors (p = 0.003). CYFRA 21-1 levels significantly decreased after surgery (p < 0.001). A high CYFRA 21-1 level before surgery was an independent prognostic factor for survival (p = 0.043). CONCLUSIONS A high CYFRA 21-1 level is associated with tumor progression and poor survival in patients with esophageal squamous cell carcinoma.

Synergistic antitumor effect of antiangiogenic factor genes on colon 26 produced by low-voltage electroporation.

Antiangiogenic factors are potent endothelial cell growth inhibitors that have been shown to inhibit angiogenesis in vitro and tumor growth in mice. We have demonstrated the synergistic antitumor effect of antiangiogenic genes (mouse angiostatin: pBLAST-mAngio; and mouse endostatin: p-BLAST42-mEndo XV) delivered to tumors by low-voltage electroporation in mouse colon 26 models. A synergistic antitumor effect was strongly suggested by in vivo tumor growth kinetics, as well as in survival studies with the mice. RT-PCR confirmed that the fragments of each gene were transferred by low-voltage electroporation in the tumor. Decreased microvessel density measurements in tumors also confirmed the efficacy of the synergistic antitumor effect of both genes. Significant growth inhibition was observed in mice treated with a 1:1 proportion of angiostatin and endostatin genes, and the order of the both genes transferred (first the endostatin gene, followed 1 week later by the angiostatin gene) had a profound inhibitory effect on tumor growth. These data suggest that in vivo delivery of antiangiogenic genes with low-voltage electroporation could be a possible therapeutic strategy for established solid tumors when both genes were applied in combination.

Enhancement of chemosensitivity toward peplomycin by calpastatin-stabilized NF-κB p65 in esophageal carcinoma cells : Possible involvement of Fas/Fas-L synergism

Chemosensitivity to anticancer drugs was compared between two human esophageal carcinoma cell lines, T.Tn and YES-6 cells. T.Tn cells were more resistant than YES-6 cells to peplomycin (PEP) but not to the other anticancer drugs such as camptothecin, mitomycin C and cytosine arabinoside. Western blot analysis showed higher expression levels of m-calpain and activated μ-calpain in T.Tn cells than in YES-6 cells. On the other hand, YES-6 cells showed a high expression level of calpastatin, which is a calpain-specific endogenous inhibitor. To investigate whether calpain activity was involved in the chemosensitivity, T.Tn cells were transfected with calpastatin cDNA in an inducible expression vector. The induction of calpastatin was accompanied by increased chemosensitivity to PEP. The increases in calpastatin levels were followed by serial increases in the expression levels of NF-κB p65 and Fas. Since purified m- or μ-calpain degraded NF-κB p65 in vitro, it is possible that calpastatin suppressed calpain-mediated degradation of NF-κB p65. Fas ligand (Fas-L) protein levels increased after treatment of the parental T.Tn and calpastatin-transfected cells with PEP, suggesting the synergism between calpastatin-induced Fas and PEP-induced Fas-L. These results suggest that calpain/calpastatin expression levels are effective markers for predicting the sensitivity of human esophageal carcinoma cells to PEP.

Identification of a novel SEREX antigen family, ECSA, in esophageal squamous cell carcinoma

BackgroundDiagnosis of esophageal squamous cell carcinoma (SCC) may improve with early diagnosis. Currently it is difficult to diagnose SCC in the early stage because there is a limited number of tumor markers available.ResultsFifty-two esophageal SCC SEREX antigens were identified by SEREX (serological identification of antigens by recombinant cDNA expression cloning) using a cDNA phage library and sera of patients with esophageal SCC. Sequence analysis revealed that three of these antigens were similar in amino acid sequences, and they were designated as ECSA (e sophageal c arcinoma S EREX a ntigen)-1, -2 and -3. The ECSA family was also similar to an EST clone, hepatocellular carcinoma-associated antigen 25a (HCA25a). Serum antibody levels to ECSA-1, -2 and -3 were significantly higher in patients with esophageal SCC than in healthy donors. Based on the conserved amino acid sequences, three peptides were synthesized and used for enzyme-linked immunosorbent assays (ELISA). The serum antibody levels against one of these peptides were significantly higher in patients with esophageal SCC. This peptide sequence was also conserved in FAM119A, GOSR1 and BBS5, suggesting that these are also ECSA family members. Reverse transcription followed by quantitative PCR analysis showed that the mRNA expression levels of ECSA-1, -2 and -3 and FAM119A but not of HCA25a, GOSR1 and BBS5 were frequently elevated in esophageal SCC tissues.ConclusionsWe have identified a new gene family designated ECSA. Serum antibodies against the conserved domain of the ECSA family may be a promising tumor marker for esophageal SCC.

Identification of Makorin 1 as a novel SEREX antigen of esophageal squamous cell carcinoma

BackgroundEsophageal squamous cell carcinoma (SCC) represents one of the most malignant tumors. To improve the poor prognosis, it is necessary to diagnose esophageal SCC at early stages using new tumor markers. SEREX (serological identification of antigens by recombinant cDNA expression cloning) is suitable for large-scale screening of tumor antigens and has been applied for various types of human tumors.MethodsTumor markers of esophageal squamous cell carcinoma (SCC) were screened by SEREX method. The presence of serum anti-makorin 1 (MKRN1) antibodies (s-MKRN1-Abs) was examined by Western blotting using bacterially expressed MKRN1 protein. The expression levels of MKRN1 mRNA in tissues were examined by RT-PCR. The biological activity of MKRN1 was examined by transfection of ras-NIH3T3 mouse fibroblasts with MKRN1 cDNA. Major ubiquitinated proteins in MKRN1-transfected cells were identified by immunoprecipitation with anti-ubiquitin antibody followed by mass spectrometry.ResultsMKRN1 was identified as a novel SEREX antigen of esophageal SCC. Although a total of 18 (25%) of 73 patients with esophageal SCC had s-MKRN1-Abs, none of the 43 healthy donors had a detectable level of s-MKRN1-Abs. There was no correlation between the presence of s-MKRN1-Abs and clinicopathological variables other than histological grading. Well-differentiated tumors were associated significantly with the presence of s-MKRN1-Abs in the patients. The mRNA levels of MKRN1 were frequently higher in esophageal SCC tissues than in the peripheral normal esophageal mucosa. Stable transfection of ras-NIH3T3 cells with MKRN1 cDNA induced prominent morphological changes such as enlargement of the cell body and spreading. Ubiquitination of 80- and 82-kDa proteins were clearly observed in MKRN1-transfected cells but not in the parental cells, which were identified as L-FILIP (filamin A interacting protein 1).ConclusionMKRN1 is a novel SEREX antigen of esophageal SCC, and s-NKRN1-Abs can be a candidate of diagnostic markers of esophageal SCC with high specificity. It is plausible that MKRN1 is involved in carcinogenesis of the well-differentiated type of tumors possibly via ubiquitination of L-FILIP.

Mode of Lymphadenectomy and Surgical Outcome of Upper Thoracic Esophageal Squamous Cell Carcinoma

IntroductionOnly a few studies have evaluated the impact of clinicopathological variables and cervical lymphadenectomy on survival in patients with upper thoracic esophageal squamous cell carcinoma (SCC).Material and MethodsFrom 1960 to 2005, a total of 167 consecutive patients with upper thoracic esophageal SCC underwent esophagectomy. Of these patients, 108 underwent surgery between 1960 and 1989 and 59 between 1990 and 2005. A total of 65 patients were treated with cervical lymphadenectomy. Univariate and multivariate analyses were performed to evaluate the impact of clinicopathological variables on surgical outcome and possible predictors for cervical lymph node metastasis.Results and DiscussionThe overall 5-year survival of the later period was significantly better than the former period (43% vs 13%, p < 0.01). Based on Cox’s proportional hazards model, T3/T4 tumors, thoracic or abdominal node metastasis, venous invasion, residual cancer, absence of cervical lymphadenectomy, and hospital morbidity were independent risk factors for reduced survival in patients with upper thoracic esophageal SCC. A total of 31 (48%) of 65 patients who underwent cervical lymphadenectomy showed positive nodes in cervical field.ConclusionBased on logistic regression analysis, T3/T4 tumors and recurrent nerve node metastasis were possible risk factors for cervical node metastasis.