Tomoko Seya

Overexpressed fibroblast growth factor receptor 2 in the invasive front of colorectal cancer: A potential therapeutic target in colorectal cancer

Fibroblast growth factor receptor 2 (FGFR2) is considered a novel therapeutic target for various cancer. We used a silencing strategy to clarify the effect of reduced FGFR2 expression in human colorectal cancer (CRC) cells. The invasive front of cancer cells exhibited stronger FGFR2 expression than the surface area of the cancers. FGFR2 shRNA-transfected LoVo cells inhibited cell migration, invasion and tumor growth in vitro and in vivo. Thus, FGFR2 plays important roles in CRC progression in association with tumor cell migration, invasion and growth, and FGFR2 might be a novel therapeutic target for CRC.

Fibroblast Growth Factor Receptor 2 IIIc as a Therapeutic Target for Colorectal Cancer Cells

A high percentage of colorectal carcinomas overexpress a lot of growth factors and their receptors, including fibroblast growth factor (FGF) and FGF receptor (FGFR). We previously reported that FGFR2 overexpression was associated with distant metastasis and that FGFR2 inhibition suppressed cell growth, migration, and invasion. The FGFR2 splicing isoform FGFR2IIIb is associated with well-differentiated histologic type, tumor angiogenesis, and adhesion to extracellular matrices. Another isoform, FGFR2IIIc, correlates with the aggressiveness of various types of cancer. In the present study, we examined the expression and roles of FGFR2IIIc in colorectal carcinoma to determine the effectiveness of FGFR2IIIc-targeting therapy. In normal colorectal tissues, FGFR2IIIc expression was weakly detected in superficial colorectal epithelial cells and was not detected in proliferative zone cells. FGFR2IIIc-positive cells were detected by immunohistochemistry in the following lesions, listed in the order of increasing percentage: hyperplastic polyps < low-grade adenomas < high-grade adenomas < carcinomas. FGFR2IIIc immunoreactivity was expressed in 27% of colorectal carcinoma cases, and this expression correlated with distant metastasis and poor prognosis. FGFR2IIIc-transfected colorectal carcinoma cells showed increased cell growth, soft agar colony formation, migration, and invasion, as well as decreased adhesion to extracellular matrices. Furthermore, FGFR2IIIc-transfected colorectal carcinoma cells formed larger tumors in subcutaneous tissues and the cecum of nude mice. Fully human anti-FGFR2IIIc monoclonal antibody inhibited the growth and migration of colorectal carcinoma cells through alterations in cell migration, cell death, and development-related genes. In conclusion, FGFR2IIIc plays an important role in colorectal carcinogenesis and tumor progression. Monoclonal antibody against FGFR2IIIc has promising potential in colorectal carcinoma therapy. Mol Cancer Ther; 11(9); 2010–20. ©2012 AACR.

Antiangiogenic effect of Octreotide inhibits the growth of human rectal neuroendocrine carcinoma

Background: Somatostatin and its analogues have antitumor effects on foregut and midgut neuroendocrine (NE) tumors, but their effect on hindgut NE tumors is unclear. We examined the effect of the somatostatin analogue, octreotide, on human rectal NE carcinoma. Materials and Methods: Expression of somatostatin receptor (sst) on NE carcinoma was examined by immunohistochemical staining. Octreotide was added in cell culture medium in order to investigate antiproliferative effect toward NE carcinoma in vitro. Octreotide was administered for 6 weeks to nude mice xenografted with NE carcinoma. We investigated the effect of octreotide on the tumor histologically. The plasma levels of VEGF and bFGF were measured. Results: The NE carcinoma and endothelial cells expressed sst. Octreotide induced NE carcinoma to apoptosis in vitro and in vivo. Octreotide-treated tumors had a massive necrotic area (62.7 ± 19.3% treated vs. 39.7 ± 20.34% untreated, p < 0.05). Microvessels in the treated tumor were decreased (264.0 ± 48.2/mm2 treated vs. 341.4 ± 56.6/mm2 untreated, p < 0.05). The plasma levels of VEGF and bFGF were reduced by octreotide. Conclusions: Octreotide induces rectal NE carcinoma to apoptosis and inhibits angiogenesis in the tumor. These result in tumor necrosis. Octreotide has an antitumor effect on rectal NE carcinoma.

A study of histopathological assessment criteria for assessing malignancy of gastrointestinal stromal tumor, from a clinical standpoint.

BackgroundAs no established histopathological criteria exist for assessing the malignant potential of gastrointestinal stromal tumor (GIST), recurrence or metastasis is occasionally observed in lesions diagnosed histopathologically as benign. The present study aimed to clarify the histopathological criteria for assessing the malignancy of GIST, from a clinical standpoint.MethodsThe subjects were 22 patients with GIST expressing CD117 (c-kit) and/or CD34, who were followed up for more than 2 years. Clinically, GIST malignancy was diagnosed if any of the following criteria were met: peripheral invasive growth, lymph node metastasis, metastasis to another organ, peritoneal dissemination, recurrence, or death. GIST was also categorized as either benign or malignant by a new histological malignancy classification system, based on the determination of significant factors indicating malignancy in the clinical classification system above.ResultsSignificant factors for malignancy identified in the clinical malignancy classification were: tumor hemorrhage/necrosis (present vs absent; P = 0.0053), tumor size (<5 cm vs ≥5 cm; P = 0.0022), and Ki-67 labeling index (<3% vs ≥3%; P = 0.0002). A new histological malignancy classification, based on a combination of these three factors, was developed. A significant correlation existed between the clinical system and the new histological malignancy classification system (P = 0.0008). The recurrence-free survival rate was 100% in the histologically benign cases and 37.5% in the histologically malignant cases (P = 0.0012).ConclusionsThe new histological malignancy classification for GIST was demonstrated to be useful from a clinical standpoint.

Myoepithelial hamartoma of the small bowel: Report of a case

Benign small bowel tumors seldom cause symptoms, due to the fluid content and distensibility of the small bowel. We herein present the case of a solitary ileal hamartoma causing melena and abdominal pain in a 24-year-old man. The diagnosis of a submucosal ileal tumor was made after performing small bowel barium studies. Surgical treatment was undertaken, and a histological examination of the excised lesion, which showed a partially ulcerated tumor surface and extended from the submucosa to the subserosa, revealed numerous cystic glands of various sizes together with bundles of proliferating smooth muscle cells. Histochemical and immunohistochemical investigations were performed for differential diagnosis, and the tumor features were consistent with a diagnosis of ileal myoepithelial hamartoma. In the literature, small intestinal myoepithelial hamartomas are quite rare and this is the first report of a myoepithelial hamartoma causing melena.

Establishment and Characterization of Two New Rectal Neuroendocrine Cell Carcinoma Cell Lines

Background: Human colorectal neuroendocrine cell carcinoma (NEC) is a rare disease with a poor prognosis. The biological behavior of NEC remains poorly understood. Materials and Methods: We established two new NEC cell lines from a patient with rectal neuroendocrine carcinoma, NECS-P and NECS-L from the primary tumor and a liver metastasis, respectively. We investigated the biological differences between the two cell lines to study the mechanisms involved in liver metastasis. Results: There was no difference between NECS-P and NECS-L in the morphological, ultrastructural and immunohistochemical studies. After addition of TGF-β1, the doubling times of NECS-P were increased in a dose-dependent manner relative to untreated cells, whereas TGF-β1 had no effect on NECS-L. The attachment and chemotactic response of the two cell lines were not enhanced by TGF-β1. The invasive capacity and the production of matrix metalloproteinase-2 (MMP-2) were significantly increased only in NECS-L following the addition of TGF-β1. When anti-MMP-2 antibody was added to the medium with TGF-β1, NECS-L invasion was inhibited. Conclusion: It is considered that these differences are important to understand the mechanisms of liver metastasis of NEC.

Establishment and Characterization of a Human Rectal Neuroendocrine Carcinoma Xenograft into Nude Mice

Background: Carcinoid tumor has been recognized as having a much wider spectrum than was previously thought. Now the term ‘neuroendocrine carcinoma’ (NEC) has been suggested to describe malignant epithelial tumors of neuroendocrine differentiation. Its biological behavior has not been well characterized because of the lack of in vivo models. Materials and Methods: A metastatic inguinal lymph node from rectal NEC was used for heterotransplantation into nude mice. Histochemical and immunohistochemical stainings were performed in addition to ultrastructural investigations. Hormonal peptides were measured in both xenograft tumor tissue and serum. Results: We succeeded in heterotransplantation of human rectal NEC into nude mice. To date tumorigenicity has been retained for approximately 38 months. The xenograft tumor was a histopathologically identical tumor. The immunohistochemical expression of the various hormonal peptides in the xenograft was essentially the same as that of the primary rectal tumor. Tissue and serum hormonal peptides in the xenografted tumor were measured. Serum glucagon and serotonin were significantly higher than in control mice. Conclusions: The expression of various hormonal peptides in NEC may vary depending on the surrounding environment. The establishment of NEC in xenografts provides a model for further study of the biological behavior of NEC, as well as the in vivo effects of chemotherapeutic agents on tumor growth and the release of hormonal peptides.

Complete response of a patient with advanced gastric cancer, showing Epstein-Barr virus infection, to preoperative chemotherapy with S-1 and cisplatin

Here we report the case of a patient with advanced gastric cancer with esophageal invasion who was treated with chemotherapy using S-1 and cisplatin (CDDP) preoperatively. The patient was a 72-year-old woman who was diagnosed with advanced gastric cancer (T3N2M0) with esophageal invasion. S-1 was orally administered at 80 mg/day (60 mg/m2 per day) on days 1–14 and CDDP was infused at 80 mg/day (60 mg/m2 per day) on day 8, followed by a 1-week rest. Marked reductions in the sizes of the primary tumor and metastatic lymph nodes around the stomach were observed after two cycles of the therapy. Adverse reactions occurring during the therapy were only grade 2 gastrointestinal disorder and grade 1 leukocytopenia. Radiological and endoscopic examinations before surgery showed that a partial response (PR) had been achieved. The patient underwent curative surgery consisting of total gastrectomy, D2 lymph node dissection, and splenectomy. Her postoperative course was uneventful, without surgical complications. No gastric cancer cells were detected in the primary lesion or lymph nodes by immunohistochemical staining with cytokeratin, confirming a histological complete response (CR). As Epstein-Barr virus-encoded small RNA (EBER) had been detected by in-situ hybridization in the gastric cancer cells of a biopsy specimen, this tumor was diagnosed as an Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC), which was effectively treated with S-1 and cisplatin chemotherapy.

Abstract 1194: Fibroblast growth factor receptor 2 as a novel therapeutic target for colorectal cancer cell growth

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Background: Colorectal carcinoma (CRC) is one of the most common cancers, and its morbidity is increasing yearly. New therapeutic strategies such as molecular-targeted agents are a high priority for advanced CRC. The multiple alterations in oncogenes and tumor suppressor genes in conjunction with the overexpression of mitogenic or angiogenic growth factors and their receptors, and interaction of the growth factors and receptors contribute to the biological aggressiveness of CRC. A high percentage of CRCs overexpress a number of growth factors and their receptors, including fibroblast growth factor 2 (FGF2), FGF1, fibroblast growth factor receptor 1 (FGFR1) and FGFR2. Recent studies have shown that gene amplification or missence mutation of FGFR2 occurs in gastric cancer, lung cancer, breast cancer, ovarian cancer, endometrial cancer and melanoma. Single nucleotide polymorphisms (SNPs) of FGFR2 are associated with increased risk of breast cancer. Furthermore, inhibition of activated mutation of FGFR2 induced apoptosis and growth inhibition of endometrial carcinoma; therefore, FGFR2 has been considered as a novel therapeutic target for cancers. However, there have been no reports about the inactivation of FGFR2 signaling pathways in CRCs. In this study, we used a silencing strategy to clarify the efficacy of knock down of FGFR2 in human CRC cells. Methods: Immunohistochemical analysis was performed to examine the expression patterns of FGFR2 in human colorectal adenocarcinoma tissues (N=95). Furthermore, FGFR2 short hairpin RNA (shRNA)-transfected CRC cell lines were established from LoVo cells. We have also transfected sham vectors to LoVo cells as negative controls. Cell proliferation, migration, invasion, morphology, and soft agar colony formation assays were performed in FGFR2-shRNA-transfected LoVo cells (Sh) and sham cells (Sc). Results: In CRC cases, FGFR2 immunoreactivity was strongly expressed in cancer cells in the invasive front of cancer tissues. The expression levels of FGFR2 mRNA and protein were low in Sh cells, as compared with Sc cells and wild type cells. Sh cells did not show characteristic morphological alterations as compared to Sc cells. Cell migration and invasion as determined by Boyden chamber assay and time-lapse analysis showed no significant differences between Sh and Sc cells. However, growth rates and colony-forming activities of Sh cells were lower than those of Sc cells in vitro, and tumor volume of subcutaneously implanted Sh cells was low as compared with that of Sc cells in nude mice. Conclusion: These findings suggest that FGFR2 plays important roles in CRC cell growth. FGFR2 may thus serve as a novel therapeutic molecular target for CRCs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1194. doi:10.1158/1538-7445.AM2011-1194

Abstract 285: Fibroblast growth factor receptor 2IIIc enhances the growth of colorectal adenocarcinoma cells

Backgrounds: Colorectal carcinoma (CRC) is one of the most common cancers throughout the world, and the prognosis remains unfavorable when the disease has progressed to an unresectable stage. New therapeutic strategies such as molecular-targeted agent are a high priority for advanced CRC. Single nucleotide polymorphisms of Fibroblast growth factor receptor 2 (FGFR2) gene are associated with breast and endometrial carcinogenesis. Therefore, FGFR2 has been noted as a novel candidate for molecular targeting of certain cancers. Alternative splicing variants of FGFR2, IIIb and IIIc, determine the binding specificity of fibroblast growth factor (FGF) members, and class switch of FGFR2IIIb to FGFR2IIIc is associated with a more malignant phenotype in prostate and bladder cancers. In CRCs, we have previously reported that overexpression of FGFR2IIIb was associated with the well-differentiated histological type, and expression of FGF7, a specific ligand for FGFR2IIIb was related to angiogenesis and adhesion to type-IV collagen. However, the expression and role of FGFR2IIIc in CRC have not been well clarified. In the present study, we examine the expression and roles of FGFR2IIIc mRNA and proteins in CRC cell lines and human CRC tissues. Methods: To determine the expression of FGFR2IIIc, we used immunohistochemical staining (IHC) and in situ hybridization analysis (ISH) in human colorectal tissues; the tissues were diagnosed as hyperplastic polyp, adenoma, adenocarcinoma and carcinoma in/with adenoma, according to the criteria of the World Health Organization. Furthermore, we constructed a FGFR2 IIIc-gene-transfected CRC cell line from DLD-1cells and FGFR2IIIc- shRNA-transfected CRC cell line from LoVo cells, and examined the effects of FGFR2 IIIc on cell behaviors. Results: In normal colorectal tissues, IHC and ISH showed the expression of FGFR2IIIc in fibroblasts, endothelium and the surface layer of normal colorectal epithelium. The expression level of FGFR2IIIc was increased in the following order; carcinoma > adenoma > hyperplastic polyp. In CRC cases, expression of FGFR2IIIc correlates with liver metastasis and poor prognosis. FGFR2IIIc-stably transfected DLD-1 cells, which overexpress FGFR2 IIIc, induced increases in colony-forming activities. In contrast, FGFR2IIIc shRNA-stably transfected LoVo cells, which express a lower level than sham transfected cells, induced decreases in colony-forming activities. Heterotopic and orthotopic implantation of FGFR2 IIIc-transfected DLD-1 cells in nude mice increased the tumor volume compared to that in mice receiving sham-transfected cells. Conclusion: These findings suggest that FGFR2IIIc plays important roles in colorectal carcinogenesis as well as tumor progression. FGFR2IIIc may thus serve as a novel candidate for molecular targeting in CRCs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 285.