Leishmania species cause a spectrum of human diseases in tropical and subtropical regions of the world. We have sequenced the 36 chromosomes of the 32.8-megabase haploid genome of Leishmania major (Friedlin strain) and predict 911 RNA genes, 39 pseudogenes, and 8272 protein-coding genes, of which 36% can be ascribed a putative function. These include genes involved in host-pathogen interactions, such as proteolytic enzymes, and extensive machinery for synthesis of complex surface glycoconjugates. The organization of protein-coding genes into long, strand-specific, polycistronic clusters and lack of general transcription factors in the L. major, Trypanosoma brucei , and Trypanosoma cruzi (Tritryp) genomes suggest that the mechanisms regulating RNA polymerase II–directed transcription are distinct from those operating in other eukaryotes, although the trypanosomatids appear capable of chromatin remodeling. Abundant RNA-binding proteins are encoded in the Tritryp genomes, consistent with active posttranscriptional regulation of gene expression.

Most mammary gland development occurs after birth under the control of systemic hormones. Estrogens induce mammary epithelial cell proliferation during puberty via epithelial estrogen receptor ␣ (ER␣) by a paracrine mechanism. Epidermal growth factor receptor (EGFR) signaling has long been implicated downstream of ER␣ signaling, and several EGFR ligands have been described as estrogen-target genes in tumor cell lines. Here, we show that amphiregulin is the unique EGF family member to be transcriptionally induced by estrogen in the mammary glands of puberal mice at a time of exponential expansion of the ductal system. In fact, we find that estrogens induce amphiregulin through the ER␣ and require amphiregulin to induce proliferation of the mammary epithelium. Like ER␣, amphiregulin is required in the epithelium of puberal mice for epithelial proliferation, terminal end buds formation, and ductal elongation. Subsequent stages, such as sidebranching and alveologenesis, are not affected. When amphiregulin ؊/؊ mammary epithelial cells are in close vicinity to wild-type cells, they proliferate and contribute to all cell compartments of the ductal outgrowth. Thus, amphiregulin is an important paracrine mediator of estrogen function specifically required for pubertyinduced ductal elongation, but not for any earlier or later developmental stages.ductal morphogenesis ͉ epithelial-stromal cross-talk ͉ paracrine

breast cancer ͉ DNA damage response ͉ medullary carcinoma

Radiotherapy is widely used to treat human cancer. Patients locally recurring after radiotherapy, however, have increased risk of metastatic progression and poor prognosis. The clinical management of postradiation recurrences remains an unresolved issue. Tumors growing in preirradiated tissues have an increased fraction of hypoxic cells and are more metastatic, a condition known as tumor bed effect. The transcription factor hypoxia inducible factor (HIF)-1 promotes invasion and metastasis of hypoxic tumors, but its role in the tumor bed effect has not been reported. Here, we show that tumor cells derived from SCCVII and HCT116 tumors growing in a preirradiated bed, or selected in vitro through repeated cycles of severe hypoxia, retain invasive and metastatic capacities when returned to normoxia. HIF activity, although facilitating metastatic spreading of tumors growing in a preirradiated bed, is not essential. Through gene expression profiling and gain-and loss-of-function experiments, we identified the matricellular protein CYR61 and AVB5 integrin as proteins cooperating to mediate these effects. The anti-AV integrin monoclonal antibody 17E6 and the small molecular AVB3/ AVB5 integrin inhibitor EMD121974 suppressed invasion and metastasis induced by CYR61 and attenuated metastasis of tumors growing within a preirradiated field. These results represent a conceptual advance to the understanding of the tumor bed effect and identify CYR61 and AVB5 integrin as proteins that cooperate to mediate metastasis. They also identify AV integrin inhibition as a potential therapeutic approach for preventing metastasis in patients at risk for postradiation recurrences. [Cancer Res 2008;68(18):7323-31]

Tumor angiogenesis promotes tumor growth and metastasis. Anti-angiogenic therapy in combination with chemotherapy is used for the treatment of metastatic cancers, including breast cancer but therapeutic benefits are limited. Mobilization and accumulation of myeloid-derived suppressor cells (MDSC) during tumor progression and therapy have been implicated in metastasis formation and resistance to antiangiogenic treatments. Here, we used the 4T1 orthotopic syngenic mouse model of mammary adenocarcinoma to investigate the effect of VEGF/VEGFR-2 axis inhibition on lung metastasis, MDSC and regulatory T cells (Tregs). We show that treatment with the anti-VEGFR-2 blocking antibody DC101 inhibits primary tumor growth, angiogenesis and lung metastasis. DC101 treatment had no effect on MDSC mobilization, but partially attenuated the inhibitory effect of mMDSC on T cell proliferation and decreased the frequency of Tregs in primary tumors and lung metastases. Strikingly, DC101 treatment induced the expression of the immune-suppressive molecule arginase I in mMDSC. Treatment with the arginase inhibitor N v -hydroxy-nor-Arginine (Nor-NOHA) reduced the inhibitory effect of MDSC on T cell proliferation and inhibited number and size of lung metastasis but had little or no additional effects in combination with DC101.In conclusion, DC101 treatment suppresses 4T1 tumor growth and metastasis, partially reverses the inhibitory effect of mMDSC on T cell proliferation, decreases Tregs in tumors and increases arginase I expression in mMDSC. Arginase inhibition suppresses lung metastasis independently of DC101 effects. These observations contribute to the further characterization of the immunomodulatory effect of anti-VEGF/VEGFR2 therapy and provide a rationale to pursue arginase inhibition as potential anti-metastatic therapy.

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Purpose: A blood test for early detection of colorectal cancer is a valuable tool for testing asymptomatic individuals and reducing colorectal cancer-related mortality. The objective of this study was to develop and validate a novel blood test able to differentiate patients with colorectal cancer and adenomatous polyps (AP) from individuals with a negative colonoscopy.Experimental Design: A case-control, multicenter clinical study was designed to collect blood samples from patients referred for colonoscopy or surgery. Predictive algorithms were developed on 75 controls, 61 large AP (LAP) !1 cm, and 45 colorectal cancer cases and independently validated on 74 controls, 42 LAP, and 52 colorectal cancer cases (23 stages I-II) as well as on 245 cases including other colorectal findings and diseases other than colorectal cancer. The test is based on a 29-gene panel expressed in peripheral blood mononuclear cells alone or in combination with established plasma tumor markers.Results: The 29-gene algorithm detected colorectal cancer and LAP with a sensitivity of 79.5% and 55.4%, respectively, with 90.0% specificity. Combination with the protein tumor markers carcinoembryonic antigen (CEA) and CYFRA21-2 resulted in a specificity increase (92.2%) with a sensitivity for colorectal cancer and LAP detection of 78.1% and 52.3%, respectively.Conclusions: We report the validation of a novel blood test, Colox Ò , for the detection of colorectal cancer and LAP based on a 29-gene panel and the CEA and CYFRA21-1 plasma biomarkers. The performance and convenience of this routine blood test provide physicians a useful tool to test average-risk individuals unwilling to undergo upfront colonoscopy.

As part of the EULEISH international genome project, a region of 74,674 nucleotides from chromosome 21 of Leishmania major Friedlin was subcloned and sequenced; and 31 new coding sequences were predicted. Of particular interest was a unique coding strand switching region covering 1.6 kb of DNA; and this was subjected to further investigation. Bioinformatic analysis of this region revealed an unusually high AT composition, a lack of putative hairpins and a strong curvature of the DNA in agreement with the structural characteristics of similar regions of other Leishmania chromosomes. These observations and a comparison with the secondary DNA structure of four other Leishmania chromosomes and chromosomes of different organisms could suggest a functional role of this region in transcription and mitotic division.