Nonstandard abbreviations used: antigen (Ag); bone marrow (BM); CG-rich motif (CpG); complete medium (CM); control oligonucleotide (ODN-CTR); effector/target (E/T); Fms-like thyrosine kinase 3 ligand (Flt3L); Langerhans cell (LC); macrophage inflammatory protein-3α (MIP-3α); mean fluorescence intensity (MFI); T cell receptor (TCR). Conflict of interest:The authors have declared that no conflict of interest exists. IntroductionThe ability of tumors to escape the immune system has been a major obstacle to the development of effective tumor immunotherapy. Both central and peripheral immune tolerance have been implicated in the failure of tumor-bearing hosts to mount an immune response to their tumors. Central tolerance may play a fundamental role in the lack of response against self-tumor-associated antigens (Ag's), while peripheral tolerance may explain the lack of response against tumor-specific Ag's. DCs are believed to play a critical role in antitumor immune responses. These cells are the most potent APCs known, uniquely capable of inducing immunity to newly introduced Ag's (1, 2). Normally, DCs reside as immature cells in peripheral tissues where they sample the environment by taking up and processing local Ag's. In the presence of certain toll-like receptor ligands, these cells not only take up and process Ag's but also undergo activation and maturation and then migrate to the draining LNs where they prime specific CD4 and CD8 T cells to these Ag's. The presence in a wide range of tumors of immature DCs that are unable to stimulate T cells (3-9) suggests a possible role for these cells in the failure of tumor-bearing hosts to mount an effective antitumor response. This view is supported by a recent study in melanoma patients that showed that tumor-associated DCs are present mostly at the periphery of tumors and express low levels of costimulatory molecules, while the majority of T cells infiltrating tumors have a naive phenotype (10). The presence of naive but not memory or effector T cells in tumors may be related to the failure of tumoral DCs to provide an adequate stimulus or possibly to the induction of T cell tolerance by the immature DCs. By contrast to tumoral DCs, in vitro-generated DCs can induce an effective T cell-mediated antitumor immune response in vivo (11), indicating that the T cells of tumor-bearing hosts are capable of recognizing and responding to tumor Ag's and suggesting again that the tumor milieu prevents tumoral DCs from inducing an effective immune response. Indeed, injection of immature Ag-pulsed DCs can induce a specific tolerogenic response, while similarly pulsed DCs, when matured, induced a typical Th1 immune response (12).Based on the recognition of the central role of DCs in initiating immune responses, a variety of strategies have been devised to use DCs to stimulate immunity against tumor Ag's. Most of these strategies rely on the activation and maturation of DCs ex vivo and their subsequent reinfusion to tumor-bearing recipients after a pulse with tumor Ag's expressed as...

The RECK (reversion-inducing-cysteine-rich protein with Kazal motifs) gene was initially isolated as a transformation suppressor gene. It encodes a membrane-anchored glycoprotein with multiple serine protease inhibitor-like domains. The RECK gene is expressed widely in normal organs but is undetectable in many tumor-derived cell lines. When artificially expressed in such cell lines, RECK suppresses their invasive and metastatic activities. Clinical implications of these findings, however, remained undefined because of the lack of studies using fresh human tumor samples. In the present study, we have addressed this issue by analyzing the levels of RECK gene expression in hepatocellular carcinoma (HCC). RECK mRNA was detectable by RNA blot hybridization in all the tumorous and contiguous nontumorous tissues obtained from 64 patients with HCC. In 26 cases, the RECK expression in tumorous tissues was higher than that in nontumorous tissues. The expression of RECK protein in these tissues could also be demonstrated by immunohistochemistry. Patients with high RECK mRNA expression in tumorous tissues tended to show better survival (P ‫؍‬ .02), and such tumors had a tendency to be less invasive. Univariate and multivariate analysis revealed that the RECK mRNA expression is a novel and independent variable affecting overall survival (P ‫؍‬ .01). These findings support the hypothesis that RECK has negative effects on the invasiveness of HCC cells and suggest the feasibility of RECK mRNA as a promising prognostic molecular marker for HCC. (HEPATOLOGY 2001;33:189-195.)The RECK (reversion-inducing-cysteine-rich protein with Kazal motifs) gene was isolated by cDNA expression cloning as a gene that induces flat morphology when expressed in a v-Ki-ras-transformed NIH 3T3 cell line. 1 The RECK gene encodes a membrane-anchored glycoprotein of about 110 kDa with multiple epidermal growth factor-like repeats and serine protease inhibitor-like domains. The RECK gene was ubiquitously expressed in various normal tissues and non-neoplastic cell lines, whereas in several tumor-derived cell lines and oncogene-transformed fibroblasts, its expression was strongly suppressed. Restored expression of the RECK gene inhibited the invasive or metastatic activities of some of these tumorderived cell lines with concomitant suppression of the secretion of matrix metalloproteinase (MMP)-9 from these cells.Many efforts have been devoted to understand the molecular mechanisms of invasion and metastasis in human cancers. 2 A number of molecules, including adhesion molecules, 3,4 metalloproteinases, 5 and angiogenic factors, 6 have been implicated as key players in invasion and metastasis. Hepatocellular carcinoma (HCC) is a very common malignancy and a major cause of cancer deaths in Asian countries. Although several molecules have also been involved in the metastatic process of HCC, 7-10 none of them has shown to be of great impact on the prognosis of this disease. It is, therefore, a matter of urgency to identify novel and effective prognostic indica...

These findings indicate that Y-27632 may be useful for the clinical management of liver fibrosis.

Purpose: Photodynamic therapy (PDT), which is used clinically for the palliative treatment of cancer, induces local tumor cell death but has no effect on tumors in untreated sites.The purpose of this study was to determine if local PDT followed by intratumoral injection of nai « ve dendritic cells (IT-DC) induces systemic antitumor immunity that can inhibit the growth of untreated as well as PDT + IT-DC^treated tumors. Experimental Design: BALB/c or C57Bl/6 mice were injected s.c. with CT26 colorectal carcinoma cells and B16 melanoma cells, respectively, and following10 to12 days of tumor growth, the tumors were treated with PDTalone or PDT followed by IT-DC or IT-PBS. In other studies, tumors were established simultaneously in both lower flanks or in one flank and in the lungs, but only one flank was treated. Results:Whereas neither PDT nor IT-DC alone was effective, PDT + IT-DC eradicated both CT26 and B16 tumors in a significant proportion of animals and prolonged the survival of mice of which the tumors were not cured. The spleens of mice treated with PDT + IT-DC contained tumorspecific cytotoxic and IFN-g-secretingTcells whereas the spleens of control groups did not. Moreover, adoptive transfer of splenocytes from successfully treated CT26 tumor-free mice protected naïve animals from a subsequent challenge with CT26, and this was mediated mainly by CD8 T cells. Most importantly, PDT plus IT-DC administered to one tumor site led to tumor regression at distant sites, including multiple lung metastases. Conclusions: PDT + IT-DC induces potent systemic antitumor immunity in mice and should be evaluated in the treatment of human cancer.

Most tumor-associated Ags are self proteins that fail to elicit a T cell response as a consequence of immune tolerance. Dendritic cells (DCs) generated ex vivo have been used to break tolerance against such self Ags; however, in vitro manipulation of DCs is cumbersome and difficult to control, resulting in vaccines of variable potency. To address this problem we developed a method for loading and activating DCs, in situ, by first directing sufficient numbers of DCs to peripheral tissues using Flt3 ligand and then delivering a tumor-associated Ag and oligonucleotide containing unmethylated CG motifs to these tissues. In this study, we show in three different tumor models that this method can overcome tolerance and induce effective antitumor immunity. Vaccination resulted in the generation of CD8+ T and NK cell effectors that mediated durable tumor responses without attacking normal tissues. These findings demonstrate that unmodified tumor-associated self Ags can be targeted to DCs in vivo to induce potent systemic antitumor immunity.