Kazuya Muguruma

Antitumor Effect of Trastuzumab for Pancreatic Cancer with High HER-2 Expression and Enhancement of Effect by Combined Therapy with Gemcitabine

Purpose: The purpose of the present study was to evaluate whether trastuzumab has antitumor effect against pancreatic cancer and whether this effect is concordant with levels of HER-2, which is reportedly overexpressed in pancreatic cancer. We also investigated whether the effect is potentiated in combined therapy with gemcitabine. Experimental Design: Using immunohistochemistry and FACScan, we analyzed HER-2 expression in 16 pancreatic cancer cell lines. The in vitro antiproliferative effect of trastuzumab, alone and in combination with gemcitabine, was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The in vitro antibody-dependent cell-mediated cytotoxicity of trastuzumab was investigated by 51Cr release assay. The in vivo antitumor effect of trastuzumab, alone and in combination with gemcitabine, was evaluated in nude mouse xenograft growth. The survival benefit was evaluated in a Capan-1 orthotopic implanted nude mouse model. Results: HER-2 expression of 2+ or more was observed in 10 and of 3+ in 2 of the 16 cell lines. No in vitro growth-inhibitory effect of trastuzumab was found in any cell line, but trastuzumab induced antibody-dependent cell-mediated cytotoxicity in proportion to HER-2 expression level. Trastuzumab inhibited tumor growth in Capan-1 (HER-2: 3+) xenografts and prolonged survival in the orthotopic model. These effects were increased by combined therapy with gemcitabine. In contrast, trastuzumab exhibited no antitumor effect against PANC-1 (HER-2: 1+) or SW1990 (HER-2: 2+) xenografts. Conclusions: The antitumor effect of trastuzumab in pancreatic cancer with high HER-2 expression was shown in vitro and in vivo. Clinical application of trastuzumab is expected in pancreatic cancer with 3+ HER-2 expression.

Impact of the Preoperative Controlling Nutritional Status (CONUT) Score on the Survival after Curative Surgery for Colorectal Cancer.

Background Recently, the preoperative immune-nutritional status has been reported to correlate with the survival rate in patients with colorectal cancer (CRC). However, there have been no reports on the relationship between the controlling nutritional status (CONUT) score and the clinical outcome after curative surgery for CRC. We herein evaluated the prognostic significance of the CONUT score in patients with CRC, and then compared the accuracy of the CONUT score and the prognostic nutritional index (PNI) as a predictor of survival. Methods We retrospectively reviewed a database of 204 patients who underwent curative surgery for Stage II/III CRC. Patients were divided into two groups according to the CONUT score and the PNI. Results The five-year cancer-specific survival (CSS) rate was significantly higher at 92.7% in the low CONUT group, compared to a rate of 81.0% in the high CONUT group (p=0.0016). The five-year CSS was 71.2% in the low PNI group and 92.3% in the high PNI group, which showed a significant difference (p=0.0155). A multivariate analysis showed that lymph node metastasis and the CONUT score were independent risk factors for CSS. Conclusion This study suggested that the CONUT score is a strong independent predictor of the survival among CRC patients.

Expression of Forkhead box P3 in tumour cells causes immunoregulatory function of signet ring cell carcinoma of the stomach

Background:It was recently reported that the transcription factor Forkhead box P3 (FoxP3) is expressed not only in regulatory T cells (Tregs) but also in cancer cells. The aim of this study was to clarify the clinical significance of FoxP3 expression in gastric carcinoma.Methods:We performed immunohistochemical staining of FoxP3 to examine the association of FoxP3 expression with clinicopathological features of 194 patients with gastric cancer who underwent surgical resection from 2000 to 2010. We also investigated the immunosuppressive function of FoxP3 using gastric cancer cell lines.Results:Immunohistochemical staining indicated FoxP3-positive cells within tumour tissue including both Tregs and tumour cells. Forkhead box P3-positive tumour cells were observed in 79.3% of signet ring cell carcinoma patients, and the expression of FoxP3 showed a significant correlation with lymph node metastasis. We showed that transforming growth factor-β augmented FoxP3 mRNA expression in cell lines derived from signet ring cell carcinoma. Indoleamine-2,3-dioxygenase and galectin-1, key effectors of Treg-mediated immunosuppression, were downregulated by FoxP3 knockdown.Conclusion:Our findings suggested that FoxP3 expression by tumour cells might have important roles in immune escape of gastric carcinoma, and be associated with the malignant potential of scirrhous gastric carcinoma.

Predictive value of Bcl-2 and Bax protein expression for chemotherapeutic effect in gastric cancer : A pilot study

We investigated tissue staining for Bcl-2 and Bax proteins, which regulate apoptosis, as indicators of chemotherapeutic effect in patients with gastric cancer. In 23 patients with gastric carcinoma biopsy specimens were obtained endoscopically prior to chemotherapy and stained immunohistochemically with anti-Bcl-2 and anti-Bax antibodies. Patients then were treated with continuous infusion of 5-FU and cisplatin. No correlation was seen between chemotherapeutic effect and Bcl-2 or Bax alone. However, among the Bax-positive cases, the patients with Bcl-2-positive tumors were significantly more chemoresistant (p = 0.036) and had worse prognoses (p = 0.008) than Bcl-2-negative cases. Therefore, immunohistochemical staining for Bcl-2 protein may predict chemotherapeutic efficacy or guide specific therapeutic choices in treating Bax-positive tumors.

Reduction of 15‐hydroxyprostaglandin dehydrogenase expression is an independent predictor of poor survival associated with enhanced cell proliferation in gastric adenocarcinoma

Prostaglandin (PG) E2 promotes gastrointestinal carcinogenesis and tumor progression. We determined the correlations between pattern of expression of 15‐hydroxyprostaglandin dehydrogenase (15‐PGDH), a catabolic enzyme for biological inactivation of PGE2, in gastric adenocarcinoma and various clinicopathological factors and patient outcome in an attempt to elucidate its biological significance. In 35 of 71 cases of gastric adenocarcinoma, expression of 15‐PGDH protein was reduced in tumor tissues. Multivariate analysis revealed reduction of 15‐PGDH expression to be an independent predictor of poor survival. The proportion of Ki67‐positive cells in 15‐PGDH‐negative adenocarcinoma was higher than that in 15‐PGDH‐positive adenocarcinoma. No differences were found in clinicopathological parameters between patients with cyclooxygenase‐2 (COX‐2)‐positive tumors and those with COX‐2 negative tumors. In an in vitro study, use of specific siRNA to silence 15‐PGDH or a specific inhibitor of 15‐PGDH enhanced cell proliferation in the gastric cancer cell line AGS, which expresses 15‐PGDH. These findings suggest that reduction of 15‐PGDH is an independent predictor of poor survival associated with enhancement of cell proliferation in gastric adenocarcinoma. (Cancer Sci 2009)

Phosphorylated Smad2 in Advanced Stage Gastric Carcinoma

BackgroundTransforming growth factor β (TGFβ) receptor signaling is closely associated with the invasion ability of gastric cancer cells. Although Smad signal is a critical integrator of TGFβ receptor signaling transduction systems, not much is known about the role of Smad2 expression in gastric carcinoma. The aim of the current study is to clarify the role of phosphorylated Smad2 (p-Smad2) in gastric adenocarcinomas at advanced stages.MethodsImmunohistochemical staining with anti-p-Smad2 was performed on paraffin-embedded specimens from 135 patients with advanced gastric adenocarcinomas. We also evaluated the relationship between the expression levels of p-Smad2 and clinicopathologic characteristics of patients with gastric adenocarcinomas.ResultsThe p-Smad2 expression level was high in 63 (47%) of 135 gastric carcinomas. The p-Smad2 expression level was significantly higher in diffuse type carcinoma (p = 0.007), tumours with peritoneal metastasis (p = 0.017), and tumours with lymph node metastasis (p = 0.047). The prognosis for p-Smad2-high patients was significantly (p = 0.035, log-rank) poorer than that of p-Smad2-low patients, while a multivariate analysis revealed that p-Smad2 expression was not an independence prognostic factor.ConclusionThe expression of p-Smad2 is associated with malignant phenotype and poor prognosis in patients with advanced gastric carcinoma.

p53 protein overexpression as a predictor of the response to chemotherapy in gastric cancer.

This study was performed to evaluate p53 overexpression as a predictor of the response to chemotherapy of patients with gastric cancer. The subjects comprised 20 patients with Stage IV gastric cancer and three with locally recurrent lesions, all of whom were treated with 5-fluorouracil (5-FU) plus cisplatin (CDDP) for 4 weeks. Of the total 23 patients there were 10 responders; 2 showing complete response (CR) and 8, partial response (PR). Specimens obtained by endoscopic biopsy were immunohistochemically stained using anti-p53 protein and bcl-2 protein antibody. Of the 10 responders, 7 demonstrated negative p53 staining, and of the 13 nonresponders, 11 demonstrated positive p53 staining (P=0.013). Tissue from 3 of the responders and 7 of the nonresponders that stained for bcl-2 were positive prior to chemotherapy; however, there was no association between bcl-2 staining and chemotherapeutic effect. In conclusion, immunohistochemical identification of p53 in pretreatment tissue may represent a useful predictor for chemotherapeutic outcome in patients with gastric cancer.

A novel orthotopic implantation model of human esophageal carcinoma in nude rats: CD44H mediates cancer cell invasion in vitro and in vivo

A new orthotopic esophageal cancer model was developed by implanting fragments of xenografts of T.T human esophageal squamous carcinoma cells into the cervical esophagus of athymic rats. The rats had symptoms analogous to the human clinical course such as respiratory distress, dysphagia, vomiting of blood, or Horner syndrome, followed by death resulting from suffocation. Microscopic metastases of lymph node were observed around the tumor in 3 of 18 rats. A new cell line (T.T‐1) was established from these metastases. Flow cytometry showed that T.T‐1 and T.T parental cells had nearly the same surface levels of β1‐integrin, α2‐integrin, α3‐integrin and E‐cadherin, and no expression of CD44v3, CD44v6 and α5‐integrin. T.T‐1 cells had a higher level of CD44H, however, and a greater binding efficiency to the extracellular matrix components; laminin, type IV collagen, hyaluronic acid, and fibronectin than T.T cells. Anti‐CD44H antibody significantly decreased the binding efficiency of T.T‐1 cells. T.T‐1 cells were also significantly more invasive than T.T cells through all the extracellular matrix components except hyaluronic acid. After orthotopic implantation histological examination showed that T.T‐1 tumors invaded beyond the esophageal mucosa and tracheal muscle layer and obstructed the esophagus and trachea. No invasion was observed with T.T tumors. Rats with T.T‐1 or T.T tumors survived an average of 32.0 and 50.7 days, respectively (p < 0.01). In addition T.T‐1 tumors expressed higher levels of CD44H mRNA than T.T tumors. In summary, our newly developed orthotopic implantation model is a valid model of esophageal cancer because it followed the same clinical course experienced by humans. Moreover, using cells derived from this model, we were able to demonstrate that CD44H is involved in esophageal cancer cell invasion.

Prognostic significance of the lymphocyte-to-monocyte ratio in patients with metastatic colorectal cancer

AIM To evaluate the prognostic significance of the lymphocyte to monocyte ratio (LMR) in patients with unresectable metastatic colorectal cancer who received palliative chemotherapy. METHODS A total of 104 patients with unresectable metastatic colorectal cancer who underwent palliative chemotherapy were enrolled. The LMR was calculated from blood samples by dividing the absolute lymphocyte count by the absolute monocyte count. Pre-treatment LMR values were measured within one week before the initiation of chemotherapy, while post-treatment LMR values were measured eight weeks after the initiation of chemotherapy. RESULTS The median pre-treatment LMR was 4.16 (range: 0.58-14.06). We set 3.38 as the cut-off level based on the receiver operating characteristic curve. Based on the cut-off level of 3.38, 66 patients were classified into the high pre-treatment LMR group and 38 patients were classified into the low pre-treatment LMR group. The low pre-treatment LMR group had a significantly worse overall survival rate (P = 0.0011). Moreover, patients who demonstrated low pre-treatment LMR and normalization after treatment exhibited a better overall survival rate than the patients with low pre-treatment and post-treatment LMR values. CONCLUSION The lymphocyte to monocyte ratio is a useful prognostic marker in patients with unresectable metastatic colorectal cancer who receive palliative chemotherapy.

The outcome of surgical treatment for elderly patients with gastric carcinoma

The aim of this study was to clarify the operative mortality and long‐term survival of gastrectomy for elderly patients with gastric cancer.