Viable and stable human cancer cell lines and animal models combined with adequate clinical information are essential for future advances in cancer research and patient care. Conventional in vitro cancer cell lines are commonly available; however, they lack detailed information on the patient from which they originate, including disease phenotype and drug sensitivity. Patient-derived xenografts (PDX) with clinical information (so-called ‘cancer xenopatients’) are a promising advance that may accelerate the development of anticancer therapies. We established 61 PDX lines from 116 surgically removed tumor tissues inoculated subcutaneously into NOG mice (53% success rate). PDX lines were established from various types of epithelial tumors and also from sarcomas, including gastrointestinal stromal tumors and Ewing/PNET sarcomas. The metastatic tumors yielded PDX lines more effectively (65%) than the primary tumors (27%, P<0.001). In our PDX models, morphological characteristics, gene expression profiles, and genetic alteration patterns were all well preserved. In eight cases (7%), the transplantable xenografts for several generations were composed of large monotonous nonepithelial cells of human origin, revealed to be Epstein-Barr virus infection-associated lymphoproliferative lesions. Despite this, PDX linked with clinical information offer many advantages for preclinical studies investigating new anticancer drugs. The fast and efficient establishment of individual PDX may also contribute to future personalized anticancer therapies.

Abstract. Malignant melanoma is the most aggressive neoplasm, with severe metastatic potential. microRNAs represent a class of endogenously expressed, small non-coding RNAs that regulate gene expression. As a consequence, the translation of these mRNAs is inhibited or they are destabilized resulting in downregulation of the encoded protein.The microRNA-34 (miR-34) family, which comprises three processed microRNAs (miR-34a/b/c) was identified as the mediator of tumor suppression by p53. Many reports suggest that the miR-34s contribute to the inhibition of invasion or metastasis in various tumor types. In this study, we evaluated the expression of the miR-34 family in four human melanoma cell lines (A375, G361, C32TG and SK-MEL-24) which have the wild-type p53 gene using real-time reverse transcription PCR. We also examined their generative and invasive characteristics using the cell proliferation assay and the invasion/ migration assay, respectively. All four melanoma cell lines showed significant expression of miR-34s -A375: miR-34a 0.6176, miR-34b 0.7625, miR-34c 0.7877; G361: 7.6424, 16.4127, 22.0332; C32TG: 2.1630 C32TG: 2. , 2.1091 SK-MEL-24: 0.3621, 2.5659, 8.5907. The cell doubling times of these cell lines in h:min were as follows: A375 23:23, G361 68:24, C32TG 47:22 and SK-MEL-24 67:03. The in vitro generation times of G361 and SK-MEL-24, which showed increased expression of miR-34c, were significantly shorter than A375 with decreased expression of miR-34c (p=0.0063, ANOVA). Invasion (%) of the four cell lines was as follows: A375 44.0%, G361 22.4%, C32TG 13.8% and SK-MEL-24 45.0%. In vitro invasiveness of G361 and C32TG, which showed increased expression of miR-34a, was significantly suppressed (p= 0.005, ANOVA). These results suggest that overexpression of miR-34a and c suppresses invasive and generative potentials, respectively, in human malignant melanoma. IntroductionMalignant melanoma is the most aggressive neoplasm with severe metastatic potential. In recent decades, the incidence of malignant melanoma has steadily increased. A particularly worrying feature of the tumor is its increasing incidence and its capacity for rapid metastatic spread. microRNAs represent a class of endogenously expressed, small non-coding RNAs that regulate gene expression (1,2). As a consequence of translation, these mRNAs are inhibited or destabilized, resulting in downregulation of the encoded protein. A few microRNAs have been classified as oncogenes or tumor-suppressor genes as their expression is altered in tumors, which in some cases has been shown to contribute to the phenotypes of cancer cells. Recently, the microRNA-34 (miR-34) family was identified as the mediator of tumor suppression by p53 (1). Many reports suggest that the miR-34s contribute to inhibition of invasion or metastasis in various tumors. These facts suggest that miR-34s play an important role as inhibitors of tumor growth. However, the biological characteristics of miR-34s in human malignant melanoma are not well understood (3). In this study, w...

The extracellular matrix protein thrombospondin (TSP) plays an important role in a variety of biological processes, including cell-cell and cell-matrix interactions. The biological role of TSP-2 in invasion and metastasis is poorly understood, while it is known that TSP-1 regulates a proteolytic cascade that allows tumor cells to invade and metastasize. In this study, we examined the role of TSP-2 in tumor cell invasion and its association with proteolytic proteins, matrix metalloproteinase (MMP) and the plasminogen/plasmin system, including urokinase-type plasminogen activator (uPA), in the human pancreatic cancer cell line PANC-1. PANC-1 cells expressed a low level of TSP-2, but significant levels of TSP-1. We isolated three clones of PANC-1 transformants stably overexpressing human TSP-2 (PANC-T). PANC-T highly expressed the TSP-2 gene and protein, while TSP-1 expression was not altered. In vitro invasion assays demonstrated that the invasiveness of PANC-T clones was significantly suppressed (p<0.05; Welch test). Zymography revealed that restoration of TSP-2 synthesis in the PANC-T clones significantly inhibited MMP-9 activity (p<0.05; Welch test). uPA activity in the PANC-T clones was significantly suppressed (p<0.05; Welch test). We concluded that restoration of TSP-2 can inhibit cell invasion through the down-regulation of MMP-9 and uPA activity in pancreatic cancer cell lines. Thus, TSP-2 may be a potent inhibitor of metastasis in pancreatic cancer.

Abstract. LIM domain proteins are involved in several fundamental biological processes, including cell lineage specification, cytoskeleton organization and organ development. Zinc finger protein 185 (ZNF185) is one of the LIM domain proteins considered to be involved in the regulation of cellular differentiation and/or proliferation. However, the detailed functions and properties of ZNF185 in the multistep process of cancer biology have not yet been elucidated. In this study, we analyzed the association between ZNF185 and the clinicopathological characteristics of colon cancer, such as patient age and gender, histological type, lymphatic and venous involvement, T and N status, liver metastasis and stage. ZNF185 protein expression was immunohistochemically analyzed and ZNF185 was detected in the cancer cells of 78 of the 87 colon cancer patients. The correlation between ZNF185 and histological type was significant (P=0.010, G-test). ZNF185 expression was also significantly correlated with liver metastasis (P=0.030, G-test). A multivariate analysis using the Cox proportional hazards model was performed among cause-specific survival rate, ZNF185 expression and clinicopathological characteristics. Histological type, liver metastasis and ZNF185 expression were found to be independent prognostic indicators (P=0.028, P<0.0001 and P=0.036, respectively). Therefore, ZNF185 expression was found to be an independent indicator of liver metastasis and prognosis in patients with colon cancer.

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