Akiko Miyamoto

Prognostic value of tumor-infiltrating dendritic cells expressing CD83 in human breast carcinomas

DCs are the most potent antigen‐presenting cells that play a major role in initiating the antitumor immune response. Although the clinical significance of TIDCs has been investigated in a variety of human cancers, few studies have focused on the in situ maturation status of DCs. We have analyzed the maturation‐specific significance of TIDCs in the prognosis of patients with breast carcinoma. We evaluated 130 breast carcinomas for the presence of TIDCs using immunohistochemistry with an anti‐CD1a antibody for immature DCs and an anti‐CD83 antibody for mature DCs. Intratumoral expression of immunosuppressive cytokines was also examined. All samples contained CD1a+ TIDCs, and 82 (63.1%) samples contained CD83+ TIDCs. The number of CD83+ TIDCs was inversely correlated with lymph node metastasis and with tissue expression of VEGF and TGF‐β, whereas the number of CD1a+ TIDCs was not. Kaplan‐Meier analysis (log rank statistics) revealed a significant association of increasing number of CD83+ TIDCs with longer relapse‐free (p = 0.002) and overall (p < 0.001) survival. Furthermore, among patients with lymph node metastasis, the survival rate of those with larger numbers of CD83+ TIDCs was significantly better than that of patients with fewer CD83+ TIDCs. Multivariate analysis revealed that CD83+ TIDCs had independent prognostic relevance in breast carcinomas. The infiltration of tumors by mature DCs expressing CD83 may be of great importance in initiating the primary antitumor immune response and is confirmed as an independent, immunologic prognostic parameter for survival in patients with breast cancer.

Proteomics-based approach identifying autoantibody against peroxiredoxin VI as a novel serum marker in esophageal squamous cell carcinoma

Purpose: Detection of novel tumor-related antigens and autoantibodies will aid in diagnosis of early-stage cancer and in development of more effective immunotherapies. The purpose of this study was to identify novel tumor antigens in an esophageal squamous cell carcinoma (ESCC) cell line (TE-2) and related autoantibodies in sera from patients with ESCC using a proteomics-based approach. Experimental Design: TE-2 proteins were separated by two-dimensional PAGE, followed by Western blot analysis in which sera of patients with ESCC, healthy controls, and patients with other cancers were tested for primary antibodies. Positive spots were excised from silver-stained gels and analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Results: Sera from patients with ESCC yielded multiple spots, one of which was identified as peroxiredoxin (Prx) VI by MALDI-TOF/TOF MS. Western blot analysis against recombinant Prx VI showed reactivity in sera from 15 of 30 (50%) patients with ESCC and 2 of 30 (6.6%) healthy individuals. Autoantibody against Prx VI was found in sera from 1 of 30 (3.3%) patients with other types of cancer (colon cancer). Conclusion: We have identified for the first time an autoantibody against Prx VI in ESCC patients. The proteomic approach implemented here offers a powerful tool for identifying novel serum markers that may display clinical usefulness against cancer.

Proteomics-based identification of autoantibody against heat shock protein 70 as a diagnostic marker in esophageal squamous cell carcinoma

Detection of novel tumor-related antigens and autoantibodies in cancer patients is expected to facilitate the diagnosis of early-stage malignant tumor and establish effective new immunotherapies. The purpose of this study was to identify novel tumor antigens in an esophageal squamous cell carcinoma (ESCC) cell line (TE-2) and related autoantibodies in sera from patients with ESCC using a proteomics-based approach. TE-2 proteins were separated by two-dimensional polyacrylamide gel electrophoresis, followed by Western blot analysis in which sera from patients with ESCC, healthy controls and patients with other cancers were tested for primary antibodies. Positive spots were excised from silver-stained gels and analyzed by matrix-assisted laser disorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF-MS). Sera from patients with ESCC yielded multiple spots, one of which was identified as heat shock protein 70 (Hsp70) by MALDI-TOF/TOF-MS. Concentrations of serum Hsp70 autoantibody were significantly higher for patients with ESCC (mean, 0.412+/-0.096 mg/ml) than for patients with gastric (0.236+/-0.112 mg/ml, P<0.001) or colon cancer (0.231+/-0.120 mg/ml, P<0.001) or healthy individuals (0.207+/-0.055 mg/ml, P<0.001) by enzyme-linked immunosorbent assay. We have identified an autoantibody against Hsp70 in ESCC patients. The proteomic approach implemented herein offers a powerful tool for identifying novel serum markers that may display clinical utility against cancer.

Concomitant Overexpression of Cyclooxygenase-2 in HER-2–Positive on Smad4-Reduced Human Gastric Carcinomas Is Associated with a Poor Patient Outcome

Purpose: The expression of cyclooxygenase-2 (COX-2) is known to be involved in gastric carcinogenesis and tumor progression, but little is known about the mechanisms responsible for the up-regulation of COX-2. We examined the involvement of two growth factor-signaling systems, HER-2 and transforming growth factor (TGF)-β, in the induction of COX-2 in human gastric cancer tissue. Experimental Design: COX-2 expression was detected by immunohistochemistry in surgical specimens obtained from 166 patients with advanced gastric cancer; possible correlations between the expression of COX-2 and the expression of HER-2, TGF-β1, and Smad4, an intracellular mediator that transmits the TGF-β signal, were then analyzed. Results: COX-2 protein was overexpressed in 91 (54.8%) tumors; COX-2 overexpression was correlated with a differentiated histologic type, deep invasion, and positive lymph node metastasis. COX-2 was frequently overexpressed in HER-2–positive tumors (19 of 22, 86.4%) and in Smad4-reduced tumors (67 of 104, 64.4%) but irrelevant to the TGF-β1 expression status. The expression levels of COX-2 and HER-2 and the reduction in Smad4 were all associated with a poor patient outcome. A multivariate analysis demonstrated a significantly poor outcome for the concomitant overexpression of COX-2 in patients with Smad4-reduced tumors. Conclusions: These results support the possibility that signal transduction via HER-2 and the TGF-β/Smad system may be implicated in COX-2 expression and that the reduction of Smad4 may be, in part, of causal significance in the TGF-β-initiated overexpression of COX-2, which is associated with a poor prognosis for patients with gastric cancer.

Identification of phosphorylated serine-15 and -82 residues of HSPB1 in 5-fluorouracil-resistant colorectal cancer cells by proteomics.

To identify the proteins involved in 5-fluorouracil (5-FU) resistance, a comparison of the total and phosphorylated proteins between the human colorectal cancer (CRC) cell line DLD-1 and its 5-FU-resistant subclone DLD-1/5-FU was performed. Using 2-DE and MALDI-TOF/TOF-based proteomics, 17 up-regulated and 19 down-regulated protein spots were identified in the 5-FU-resistant DLD-1/5-FU cells compared with the parent cell lines. In DLD-1/5-FU cells, 7 anti-apoptotic proteins (HSPB1, proteasome subunit α-5, transitional endoplasmic reticulum ATPase, 14-3-3 β, 14-3-3 γ, 14-3-3 σ, and phosphoglycerate kinase 1) were up-regulated and 4 proapoptotic proteins (cofilin-1, pyruvate kinase M2, glyceraldehyde-3-phosphate dehydrogenase, and nucleophosmin) were down-regulated. The results show that the acquired drug resistance of DLD-1/5-FU cells is caused by the prevention of drug-induced apoptosis, in particular through the enhanced constitutive expression of HSPB1 and its phosphorylated form. Short interfering RNA knockdown of endogenous HSPB1 in DLD-1/5-FU cells restored the sensitivity to 5-FU. Furthermore, MALDI-TOF/TOF and 2-DE Western blot analysis identified the phosphorylated residues of HSPB1 as Ser-15 and Ser-82 in the main (diphosphorylated) form and Ser-15, Ser-78, and Ser-82 in the minor (triphosphorylated) form. The current findings indicate that phosphorylated HSPB1 may play an important role in 5-FU resistance.

Comparative proteomic analysis of paclitaxel resistance‑related proteins in human breast cancer cell lines

Paclitaxel is widely used to treat various cancers; however, resistance to this drug is a major obstacle to breast cancer chemotherapy. To identify the proteins involved in paclitaxel resistance, the present study compared the proteomes of MCF-7 human breast cancer cells and its paclitaxel-resistant subclone MCF-7/PTX. Using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry, 11 upregulated and 12 downregulated proteins were identified in MCF-7/PTX cells compared with the parental cell line. These 23 proteins were functionally classified as stress-induced chaperones, metabolic enzymes and cytoskeletal proteins. The anti-apoptotic proteins, stress-70 protein, 78-kD glucose-regulated protein, peptidyl-prolyl cis-trans isomerase A (PPIA) and heterogeneous nuclear ribonucleoprotein H3, were also upregulated in MCF-7/PTX cells. Notably, knockdown of the stress-response chaperone PPIA using small interfering RNA in MCF-7/PTX cells restored their sensitivity to paclitaxel. These findings indicated that PPIA may have an important role in paclitaxel resistance in MCF-7/PTX cells.