We have recently identified a tumor suppressor gene TSLC1 on chromosome 11q23.2 by functional complementation of a human lung cancer cell line, A549, through suppression of tumorigenicity in nude mice (1). Furthermore, we have demonstrated the two-hit inactivation of TSLC1 in primary non-small cell lung cancer, hepatocellular carcinoma, and pancreatic cancer, implying its involvement in various human cancers (1). TSLC1 encodes a member of the immunoglobulin superfamily proteins comprising three Ig-like C2-type domains, a single hydrophobic membrane-spanning ␣-helix, and a cytoplasmic domain containing a putative signaling motif (1). From the significant homology of its extracellular domain with those of NCAM1 and NCAM2, 1 we have inferred that TSLC1 is capable of mediating cell-cell interaction.Cell adhesion molecules generally fall into four major classes: the cadherins, the integrins, the selectins, and the Ig superfamily. Among them, Ig superfamily cell adhesion molecules (IgCAMs) are the largest, numbering well over 100 members in vertebrates (2). These well-characterized molecules include NCAMs (3), L1 family CAMs (4), and nectins (5-8). Whereas cadherins and integrins require divalent cations such as Ca 2ϩ or Mg 2ϩ for their adhesive activities (9), IgCAMs are usually Ca 2ϩ -or Mg 2ϩ -independent (10). Moreover, most IgCAMs have preferences for homophilic and/or heterophilic interactions (10). In combination with these interactions, IgCAMs promote a variety of cell-cell associations through cis interaction within the plane of the membranes and/or trans interaction across the membranes (2, 11). For instance, the heterophilic cis interaction between L1 and NCAM appears to enhance the homophilic trans-binding activity of L1 (12, 13). Nectins form cis-homodimers that undergo homophilic and heterophilic trans interactions with each other to mediate cell-cell adhesion (6,11).In this study, the biochemical properties and subcellular localization of TSLC1 were investigated in the cells expressing TSLC1 tagged with GFP or endogenous TSLC1. We report the physiological properties of TSLC1 along with several lines of evidence that TSLC1 is a single transmembrane glycoprotein involved in cell-cell aggregation through homophilic trans interaction.

Canonical Wnt/β-catenin signalling is essential for maintaining intestinal stem cells, and its constitutive activation has been implicated in colorectal carcinogenesis. We and others have previously identified Traf2- and Nck-interacting kinase (TNIK) as an essential regulatory component of the T-cell factor-4 and β-catenin transcriptional complex. Consistent with this, Tnik-deficient mice are resistant to azoxymethane-induced colon tumorigenesis, and Tnik−/−/Apcmin/+ mutant mice develop significantly fewer intestinal tumours. Here we report the first orally available small-molecule TNIK inhibitor, NCB-0846, having anti-Wnt activity. X-ray co-crystal structure analysis reveals that NCB-0846 binds to TNIK in an inactive conformation, and this binding mode seems to be essential for Wnt inhibition. NCB-0846 suppresses Wnt-driven intestinal tumorigenesis in Apcmin/+ mice and the sphere- and tumour-forming activities of colorectal cancer cells. TNIK is required for the tumour-initiating function of colorectal cancer stem cells. Its inhibition is a promising therapeutic approach.

Pulmonary metastasis is the most significant prognostic determinant for osteosarcoma, but methods for its prediction and treatment have not been established. Using oligonucleotide microarrays, we compared the global gene expression of biopsy samples between seven osteosarcoma patients who developed pulmonary metastasis within 4 years after neoadjuvant chemotherapy and curative resection, and 12 patients who did not relapse. We identified argininosuccinate synthetase (ASS) as a gene differentially expressed with the highest statistical significance (Welch's t test, P = 2.2 × 10 −5). Immunohistochemical analysis of an independent cohort of 62 osteosarcoma cases confirmed that reduced expression of ASS protein was significantly correlated with the development of pulmonary metastasis after surgery (log-rank test, P < 0.05). Cox regression analysis revealed that ASS was the sole significant predictive factor (P = 0.039; hazard ratio, 0.319; 95% confidence interval, 0.108-0.945). ASS is one of the enzymes required for the production of a nonessential amino acid, arginine. We showed that osteosarcoma cells lacking ASS expression were auxotrophic for arginine and underwent G 0 -G 1 arrest in arginine-free medium, suggesting that an arginine deprivation therapy could be effective in patients with osteosarcoma. Recently, phase I and II clinical trials in patients with melanoma and hepatocellular carcinoma have shown the safety and efficacy of plasma arginine depletion by stabilized arginine deiminase. Our data indicate that in patients with osteosarcoma, reduced expression of ASS is not only a novel predictive biomarker for the development of metastasis, but also a potential target for pharmacologic intervention. Mol Cancer Ther; 9(3); 535-44. ©2010 AACR.

◥Extracellular vesicles (EV) from cancer-associated fibroblasts (CAF) are composed of diverse payloads. Although CAFs impact the aggressive characteristics of gastric cancer cells, the contribution of CAF-EV to gastric cancer progression has not been elucidated. Here, we investigated the molecular mechanism of the changes in gastric cancer characteristics induced by CAF-EV. CAF abundance in gastric cancer tissues was associated with poor prognosis of patients with gastric cancer receiving chemotherapy. Moreover, CAF-EV induced tubular network formation and drug resistance of gastric cancer cells in the extracellular matrix (ECM). Comprehensive proteomic analysis of CAF-EV identified that Annexin A6 plays a pivotal role in network formation and drug resistance of gastric cancer cells in the ECM via activation of b1 integrin-focal adhesion kinase (FAK)-YAP. A peritoneal metastasis mouse model revealed that CAF-EV induced drug resistance in peritoneal tumors, and inhibition of FAK or YAP efficiently attenuated gastric cancer drug resistance in vitro and in vivo. These findings demonstrate that drug resistance is conferred by Annexin A6 in CAF-EV and provide a potential avenue for overcoming gastric cancer drug resistance through the inhibition of FAK-YAP signaling in combination with conventional chemotherapeutics.Significance: This study elucidates a novel molecular mechanism through which Annexin A6 in CAF-EV activates FAK-YAP by stabilizing b1 integrin at the cell surface of gastric cancer cells and subsequently induces drug resistance.

The frequent alterations of Hippo pathway molecules found in this study indicate the therapeutic feasibility of targeting this pathway in patients with MM.

Renal clear cell carcinoma (RCCC) is a malignant tumor with poor prognosis caused by the high incidence of metastasis to distal organs. Although metastatic RCCC cells frequently show aberrant cytoskeletal organization, the underlying mechanism has not been elucidated. DAL-1/4.1B is an actin-binding protein implicated in the cytoskeleton-associated processes, while its inactivation is frequently observed in lung and breast cancers and meningiomas, suggesting that 4.1B is a potential tumor suppressor. We studied a possible involvement of 4.1B in RCCCs and evaluated it as a clinical indicator. 4.1B protein was detected in the proximal convoluted tubules of human kidney, the presumed cell of origin of RCCC. On the other hand, loss or marked reduction of its expression was observed in 10 of 19 (53%) renal cell carcinoma (RCC) cells and 12 of 19 (63%) surgically resected RCCC by reverse transcription-PCR. Bisulfite sequencing or bisulfite SSCP analyses revealed that the 4.1B promoter was methylated in 9 of 19 (47%) RCC cells and 25 of 55 (45%) surgically resected RCCC, and inversely correlated with 4.1B expression (p < 0.0001). Aberrant methylation appeared to be a relatively early event because more than 40% of the tumors with pT1a showed hypermethylation. Furthermore, 4.1B methylation correlated with a nuclear grade (p 5 0.017) and a recurrence-free survival (p 5 0.0036) and provided an independent prognostic factor (p 5 0.038, relative risk 10.5). These results indicate that the promoter methylation of the 4.1B is one of the most frequent epigenetic alterations in RCCC and could predict the metastatic recurrence of the surgically resected RCCC. ' 2005 Wiley-Liss, Inc.Key words: tumor suppressor gene; bi-sulfite sequencing; two-hit inactivation; recurrence-free survival rate; independent prognostic factor Renal cell carcinoma (RCC) accounts for about 2% of human cancers worldwide, with an incidence of 189,000 and a mortality of 91,000 reported in the year of 2000. 1 Renal clear cell carcinoma (RCCC), which represents 75% of all RCC, exhibits frequent metastasis to distant organs without any clinical symptoms. Furthermore, 40-60% of RCCC tumors without metastasis at first presentation eventually develop metastasis as they progress. 2 Finally, metastatic RCCC becomes refractory to any therapeutic approaches, including chemo-, radio-, and hormonal therapies, resulting in a poor prognosis of patients, with a 5-year survival of less than 10%. 3 Thus, understanding the molecular mechanisms of the development and progression of RCCC is a critical issue for controlling this refractory cancer.Several genetic and epigenetic alterations have been reported in RCCC. The mutation of the VHL gene, associated with loss of heterozygosity (LOH) at the gene locus on chromosomal fragment 3p25-p26, was observed in~50% of sporadic RCCC. 4 Since the VHL encodes a component of an E3 ubiquitin ligase that promotes the degradation of hypoxia-inducible factors, loss of VHL function could be involved in angiogenesis, one of the most characteri...

CADM1 encodes a multifunctional immunoglobulin-like cell adhesion molecule whose cytoplasmic domain contains a type II PSD95/Dlg/ZO-1 (PDZ)-binding motif (BM) for associating with other intracellular proteins. Although CADM1 lacks expression in T lymphocytes of healthy individuals, it is overexpressed in adult T-cell leukemia-lymphoma (ATL) cells. It has been suggested that the expression of CADM1 protein promotes infiltration of leukemic cells into various organs and tissuesCADM1 is the recently unified nomenclature for TSLC1 (tumor suppressor in non-small cell lung cancer 1) (1), which had a variety of different names, including IGSF4A (2), RA175 (3), SgIGSF (4), SynCAM1 (5), and Necl-2 (6) due to its previously reported multiple functions. CADM1 encodes an immunoglobulin-like cell adhesion molecule with three immunoglobulin loops. The ectodomain of CADM1 mediates intercellular adhesion through homophilic or heterophilic trans-interaction between neighboring cells (7). Despite being a tumor suppressor in various carcinomas, recent DNA microarray analysis of primary adult T-cell leukemia/lymphoma (ATL) 3 cells from acute type ATL patients revealed that CADM1 was up-regulated over 30-fold in those patients through an as yet unknown mechanism (8). ATL is a neoplastic disease of CD4-positive T lymphocytes that is etiologically associated with human T-cell leukemia virus type I (HTLV-I) (9). ATL develops in 3-5% of HTLV-I-infected individuals after an extended latent period of ϳ40 -60 years (10), yet it remains an aggressive disease with poor prognosis and a median survival time of 11-13 months reported even in patients treated with the most effective first line combination chemotherapy (11). ATL is well known for its propensity of infiltrating leukemic cells into various organs and tissues, such as the skin, lungs, liver, gastrointestinal tract, central nervous system, lymph nodes, and bone (12). Previous studies reported that various cell adhesion molecules, cytokines, chemokines, and chemokine receptors are implicated in the process of ATL cell infiltration (13). Because cell adhesion is a critical step in tumor cell invasion, it has been proposed that over-* This work was supported by Grant-in-aid for Scientific Research on Priority

No abstract