Shuhei Ishikawa

Tumor Endothelial Cells Acquire Drug Resistance by MDR1 Up-Regulation via VEGF Signaling in Tumor Microenvironment

Tumor endothelial cells (TECs) are therapeutic targets in anti-angiogenic therapy. Contrary to the traditional assumption, TECs can be genetically abnormal and might also acquire drug resistance. In this study, mouse TECs and normal ECs were isolated to investigate the drug resistance of TECs and the mechanism by which it is acquired. TECs were more resistant to paclitaxel with the up-regulation of multidrug resistance (MDR) 1 mRNA, which encodes the P-glycoprotein, compared with normal ECs. Normal human microvascular ECs were cultured in tumor-conditioned medium (CM) and became more resistant to paclitaxel through MDR1 mRNA up-regulation and nuclear translocation of Y-box-binding protein 1, which is an MDR1 transcription factor. Vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) and Akt were activated in human microvascular ECs by tumor CM. We observed that tumor CM contained a significantly high level of VEGF. A VEGFR kinase inhibitor, Ki8751, and a phosphatidylinositol 3-kinase-Akt inhibitor, LY294002, blocked tumor CM-induced MDR1 up-regulation. MDR1 up-regulation, via the VEGF-VEGFR pathway in the tumor microenvironment, is one of the mechanisms of drug resistance acquired by TECs. We observed that VEGF secreted from tumors up-regulated MDR1 through the activation of VEGFR2 and Akt. This process is a novel mechanism of the acquisition of drug resistance by TECs in the tumor microenvironment.

Heterogeneity of Tumor Endothelial Cells: Comparison between Tumor Endothelial Cells Isolated from High- and Low-Metastatic Tumors

An important concept in tumor angiogenesis is that tumor endothelial cells (TECs) are genetically normal and homogeneous. However, we previously reported that TECs differ from normal ECs. Whether the characteristics of TECs derived from different tumors differ remains unknown. To elucidate this, in this study, we isolated two types of TECs from high-metastatic (HM) and low-metastatic (LM) tumors and compared their characteristics. HM tumor-derived TECs (HM-TECs) showed higher proliferative activity and invasive activity than LM tumor-derived TECs (LM-TECs). Moreover, the mRNA expression levels of pro-angiogenic genes, such as vascular endothelial growth factor (VEGF) receptors 1 and 2, VEGF, and hypoxia-inducible factor-1α, were higher in HM-TECs than in LM-TECs. The tumor blood vessels themselves and the surrounding area in HM tumors were exposed to hypoxia. Furthermore, HM-TECs showed higher mRNA expression levels of the stemness-related gene stem cell antigen and the mesenchymal marker CD90 compared with LM-TECs. HM-TECs were spheroid, with a smoother surface and higher circularity in the stem cell spheroid assay. HM-TECs differentiated into osteogenic cells, expressing activated alkaline phosphatase in an osteogenic medium at a higher rate than either LM-TECs or normal ECs. Furthermore, HM-TECs contained more aneuploid cells than LM-TECs. These results indicate that TECs from HM tumors have a more pro-angiogenic phenotype than those from LM tumors.

Medical management of recurrent aggressive angiomyxoma with gonadotropin-releasing hormone agonist

Patients with aggressive angiomyxoma may experience local recurrences. We report a case of recurrent aggressive angiomyxoma medically treated successfully with a gonadotropin‐releasing hormone agonist. A 34‐year‐old woman with a huge perineal tumor underwent an extensive resection of the abdominoperineal tumor combined with total pelvic exenteration. Histology showed aggressive angiomyxoma and the tumor cells were immunoreactive for estrogen and progesterone receptors. Although the patient had experienced no local recurrence for 12 months under adjuvant therapy with a gonadotropin‐releasing hormone agonist, a recurrence occurred 3 months after the completion of adjuvant therapy. The patient underwent medical treatment with a gonadotropin‐releasing hormone agonist and had a complete resolution of the recurrent tumor again. Hormonal treatment with a gonadotropin‐releasing hormone agonist can be applied for small primary aggressive angiomyxomas in addition to adjuvant therapy for residual tumors.

Impact of Diagnostic Ureteroscopy on Intravesical Recurrence and Survival in Patients With Urothelial Carcinoma of the Upper Urinary Tract

PURPOSE We determined whether diagnostic ureteroscopy for upper urinary tract cancer affects intravesical recurrence and cancer specific mortality. MATERIALS AND METHODS In a retrospective, multi-institutional study we evaluated 208 patients undergoing nephroureterectomy for upper urinary tract cancer who had no perioperative systemic chemotherapy, history of invasive bladder cancer, distant metastasis or incomplete followup data. Of these 208 patients 55 who composed the study group underwent diagnostic ureteroscopy before nephroureterectomy while 153 serving as controls did not. We analyzed intravesical recurrence and cancer specific survival using the Kaplan-Meier method with the log rank test used to assess significance. RESULTS There was no significant difference between the 2 groups in patient characteristics or upper urinary tract cancer stage and grade while followup, and the proportion of multiple tumors and lymphovascular invasion positive tumors were significantly greater in controls. The 2-year bladder recurrence-free survival rate was 60.0% in the study group and 58.7% in controls. There was no significant difference in the intravesical recurrence rate between the 2 groups (log rank test p = 0.972). Estimated Kaplan-Meier cancer specific survival was 88.3% and 78.1% at 5 years in the study and control groups, respectively (log rank test p = 0.0687). CONCLUSIONS Diagnostic ureteroscopy did not affect intravesical recurrence or cancer specific survival in patients with upper urinary tract cancer undergoing nephroureterectomy.

THE ROLE OF LYMPH-NODE DISSECTION IN THE TREATMENT OF UPPER URINARY TRACT CANCER: A MULTI-INSTITUTIONAL STUDY

To determine the role of lymph‐node (LN) dissection in patients undergoing surgery for upper urinary tract (UUT) cancer.

Pathological characteristics and clinical course of bladder tumour developing after nephroureterectomy

Study Type – Therapy (case series)
Level of Evidence 4

Abstract 2376: Endothelial cells acquire abnormalities by factors from tumor cells

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Recently, it has been reported that tumor microenvironment is important for tumor progression and metastasis. We have reported that tumor endothelial cells (TECs) differ from their normal counterparts, in many aspects. For example, TECs upregulate several genes, have cytogenetical abnormalities and respond differently to the growth factors such as epidermal growth factor receptor (EGFR) or some anticancer drugs (Hida et al., Cancer Res 2004, Cancer Sci 2008). In this study, we focused on the interaction between tumor cells and endothelial cells to address the mechanism of TEC abnormality. We demonstrate that cultured conditioned medium (CM) from melanoma cells cause several phenotypic changes in Human Microvascular Endothelial Cells (HMVEC). The cell proliferation of HMVEC was stimulated by melanoma CM. Furthermore, the expression level of Multi Drug Resistance Gene (MDR) was upregulated by melanoma CM treatment and HMVEC got less sensitive to Paclitaxel. It was suggested that some factors released from melanoma cause abmormalities in HMVEC phenotype. The study to elucidate mechanisms of these results are ongoing. 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 2376.

Abstract 3432: A green tea polyphenol epigallocatechin-3 gallate specifically targets tumor-associated endothelial cells

A green tea polyphenol, epigallocatechin-3 gallate (EGCG) suppresses tumor growth in vivo. We investigated mechanisms of specific tumor angiogenesis inhibition using tumor-associated endothelial cells (TECs), peripheral blood-derived ECs, and normal endothelial cells (NECs). TECs were isolated and cultured from human tumor xenografts in nude mice. Peripheral blood-derived ECs were isolated from peripheral blood of nude mice. EGCG suppressed migration of TECs and peripheral blood-derived ECs. EGCG also inhibited the phosphorylation of Akt in TECs and peripheral blood-derived ECs. The PI3K inhibitor, LY294002 blocked the migration of TECs induced by VEGF. Furthermore, VEGF-induced mobilization of CD133/VEGFR-2 double-positive cells into circulation was inhibited by EGCG. MMP-9 in the bone marrow is involved in mobilizing bone marrow-derived VEGFR-2 positive cells into peripheral circulation. Expression of MMP-9 mRNA was suppressed in bone marrow stromal cells by EGCG. In vivo model, EGCG reduced melanoma growth. Our study showed that EGCG specifically inhibits TEC and circulating EC through PI3K in EC and MMP-9 expression in bone marrow stroma. EGCG is a promising angiogenesis inhibitor for cancer therapy. 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 3432.

PATHOLOGIC CHARACTERISTICS AND CLINICAL COURSES OF BLADDER TUMORS AFTER NEPHROURETERECTOMY FOR UPPER URINARY TRACT CANCER

by genito-urinary pathologists who were blinded to the original slides and clinical outcomes. Uniand multivariate logistic regression analyses were performed. For comparison a base model was used that comprised lymph node status, pathologic stage, and tumor grade. RESULTS: LVI was found in 338 patients (24.8%). Proportion of LVI increased with advancing tumor stage (p<0.001), increasing tumor grade (p<0.001), sessile architecture (p<0.001), concomitant CIS (p<0.001), lymph node metastasis (28% vs. 72%, p<0.001), and symptoms at presentation (p=0.002). Five-years cancer recurrence and survival rates were 76.4±1.5% and 80.6±1.4% in the absence of LVI, compared to 44.4±3.1% and 49.5±3.3% in the presence of LVI, respectively (p<0.001). In multivariate analyses, LVI was an independent