Insulin gene expression is restricted to islet beta cells of the mammalian pancreas through specific control mechanisms mediated in part by specific transcription factors. The protein encoded by the pancreatic and duodenal homeobox gene 1 (PDX-1) is central in regulating pancreatic development and islet cell function. PDX-1 regulates insulin gene expression and is involved in islet cell-specific expression of various genes. Involvement of PDX-1 in islet-cell differentiation and function has been demonstrated mainly by 'loss-of-function' studies. We used a 'gain-of-function' approach to test whether PDX-1 could endow a non-islet tissue with pancreatic beta-cell characteristics in vivo. Recombinant-adenovirus-mediated gene transfer of PDX-1 to the livers of BALB/C and C57BL/6 mice activated expression of the endogenous, otherwise silent, genes for mouse insulin 1 and 2 and prohormone convertase 1/3 (PC 1/3). Expression of PDX-1 resulted in a substantial increase in hepatic immunoreactive insulin content and an increase of 300% in plasma immunoreactive insulin levels, compared with that in mice treated with control adenovirus. Hepatic immunoreactive insulin induced by PDX-1 was processed to mature mouse insulin 1 and 2 and was biologically active; it ameliorated hyperglycemia in diabetic mice treated with streptozotocin. These data indicate the capacity of PDX-1 to reprogram extrapancreatic tissue towards a beta-cell phenotype, may provide a valuable approach for generating 'self' surrogate beta cells, suitable for replacing impaired islet-cell function in diabetics.

BACKGROUND It was demonstrated previously that the Snail family of transcription factors and Smad‐interacting protein 1 (Sip1) regulate E‐cadherin and matrix metalloproteinase 2 (MMP‐2) expression, cellular morphology, and invasion in carcinoma. For the current study, the authors analyzed the relation between the expression of Snail, Slug, and Sip1; the expression of MMP‐2 and E‐cadherin; and clinical parameters in patients with metastatic ovarian and breast carcinoma. METHODS One hundred one fresh‐frozen, malignant effusions from patients who were diagnosed with gynecologic carcinomas (78 ovarian carcinomas and 23 breast carcinomas) were studied for mRNA expression of Snail, Slug, Sip1, MMP‐2, and E‐cadherin using reverse transcriptase‐polymerase chain reaction analysis. Snail mRNA and E‐cadherin protein expression levels also were studied in ovarian carcinoma effusions using in situ hybridization and immunocytochemistry. The results were analyzed for possible correlation with clinicopathologic parameters in both tumor types. RESULTS E‐cadherin mRNA expression was lower in breast carcinoma (P = 0.001), whereas Snail expression was higher (P = 0.003). The Snail/E‐cadherin ratio (P < 0.001) and the Sip1/E‐cadherin ratio (P = 0.002) were higher in breast carcinomas. Sip1 mRNA expression (P < 0.001) and Slug mRNA expression (P < 0.001) were correlated with the expression of MMP‐2 in ovarian carcinomas. The Sip1/E‐cadherin ratio was higher in primary ovarian carcinomas at the time of diagnosis compared with postchemotherapy ovarian carcinoma effusions (P = 0.003), higher in Stage IV tumors compared with Stage III tumors (P = 0.049), and higher in pleural effusions compared with peritoneal effusions (P = 0.044). In a univariate survival analysis of patients with ovarian carcinoma, a high Sip1/E‐cadherin ratio predicted poor overall survival (P = 0.018). High E‐cadherin mRNA expression predicted better disease‐free survival (P = 0.023), with a similar trend for a low Slug/E‐cadherin ratio (P = 0.07). High Snail mRNA expression predicted shorter effusion‐free survival (P = 0.008), disease‐free survival (P = 0.03), and overall survival (P = 0.008) in patients with breast carcinoma. CONCLUSIONS Transcription factors that regulate E‐cadherin were expressed differentially in metastatic ovarian and breast carcinoma. Snail may predict a poor outcome in patients who have breast carcinoma metastatic to effusions. E‐cadherin expression generally was conserved in effusions from patients with ovarian carcinoma, but the subset of patients with postulated Sip1‐induced repression of this adhesion molecule had a significantly worse outcome. This finding was in agreement with the stronger suppression of E‐cadherin by Snail and Sip1 in breast carcinoma effusions, a clinical condition associated with extremely poor survival. Cancer 2005. © 2005 American Cancer Society.

Shortage in tissue availability from cadaver donors and the need for life-long immunosuppression severely restrict the large-scale application of cell-replacement therapy for diabetic patients. This study suggests the potential use of adult human liver as alternate tissue for autologous beta-cell-replacement therapy. By using pancreatic and duodenal homeobox gene 1 (PDX-1) and soluble factors, we induced a comprehensive developmental shift of adult human liver cells into functional insulin-producing cells. PDX-1-treated human liver cells express insulin, store it in defined granules, and secrete the hormone in a glucose-regulated manner. When transplanted under the renal capsule of diabetic, immunodeficient mice, the cells ameliorated hyperglycemia for prolonged periods of time. Inducing developmental redirection of adult liver offers the potential of a cell-replacement therapy for diabetics by allowing the patient to be the donor of his own insulin-producing tissue.pancreas ͉ transdifferentiation

Pancreatic and duodenal homeobox gene-1 (PDX-1) regulates pancreas development during embryogenesis, whereas in the adult it controls ␤-cell function. Here we analyze whether PDX-1 functions as a pancreatic differentiation factor and a bona fide master regulator when ectopically expressed in mature fully differentiated liver in vivo. By ectopic and transient PDX-1 expression in liver in vivo, using the first generation recombinant adenoviruses, we demonstrate that PDX-1 induces in liver a wide repertoire of both exocrine and endocrine pancreatic gene expression. Moreover, PDX-1 induces its own expression (auto-induction), which in turn may explain the long lasting nature of the "liver to pancreas" transdifferentiation. Insulin as well glucagon-producing cells are mainly located in the proximity of hepatic central veins, possibly allowing direct hormone release into the bloodstream, without affecting normal hepatic function. Importantly, we demonstrate that hepatic insulin production triggered by Ad-CMV-PDX-1 recombinant adenovirus administration is functional and prevents streptozotocin-induced hyperglycemia in Balb/c mice even 8 months after the initial treatment. We conclude that PDX-1 plays an important instructive role in pancreas differentiation, not only from primitive gut endoderm but also from mature liver. Transconversion of liver to pancreas may serve as a novel approach for generating endocrine-pancreatic tissue that can replace malfunctioning ␤-cells in diabetics.The possible role of "master regulator" transcription factors in directing cell fate, taken together with the documented plasticity of many mature tissues and pluripotent cells, motivated us to analyze whether it is possible to redirect the developmental route of cells in liver toward a pancreatic ␤-cell phenotype. The strategy used for this purpose is ectopic expression of a specific pancreatic master regulator gene. Our hypothesis was that such a developmental redirection was most likely to occur between tissues that are developmentally related, such as liver and pancreas (1-4). Transdifferentiation of pancreas to liver has been described in both experimental models and human pathology (5-10).Pancreatic and duodenal homeobox gene-1 (PDX-1, 1 also known as IDX-1, IPF-1, STF-1, or IUF-1) possesses a dual role in the pancreas; it is essential for normal pancreas development during embryogenesis and for maintenance of ␤-cell function in the adult (11,12). During organogenesis PDX-1 is expressed in all cells differentiating toward the exocrine and endocrine components of the pancreas (11-13). In the adult, its expression is restricted to ␤-cells and to 20% of somatostatin producing ␦-cells. PDX-1 is neither expressed in glucagon producing ␣-cells nor in mature exocrine pancreas (11,12,14).We demonstrated previously that transdifferentiation of liver to pancreas could be induced by ectopic expression of PDX-1; expression of PDX-1 in liver induced expression of the otherwise silent endogenous insulin genes and was sufficient to direct the product...

Background: Exaggerated reaction to insect bites, mainly to mosquitoes, is infrequently described in patients with chronic lymphocytic leukemia. Skin lesions usually appear months to years after the diagnosis of leukemia and are unrelated to laboratory findings, disease course, or therapy.Observations: We describe 8 patients with various hematologic disorders (chronic lymphocytic leukemia, acute lymphoblastic leukemia, acute monocytic leukemia, mantle-cell lymphoma, large-cell lymphoma, and myelofibrosis) who developed insect bite-like reaction. Although the clinical picture and the histological characteristics of the lesions were typical for insect bites, none of the patients actually had a history, course, or response to treatment suggestive of arthropod assaults. In 2 patients, the eruption preceded the diagnosis of the ma-lignant neoplasm. The rash persisted for months to years and was resistant to therapies other than systemic corticosteroids. The 3 patients with chronic lymphocytic leukemia seemed to have a worse prognosis than expected for their disease. In 1, the polymerase chain reaction detected leukemic cells in the infiltrate.Conclusions: Insect bite-like reaction is an infrequent, disturbing, and difficult-to-treat nonspecific phenomenon in patients with hematologic malignant neoplasms. Since it may precede the hematologic disorder, oriented evaluation is warranted. We speculate that immunodeficiency plays a role in its pathogenesis; however, the exact pathogenesis and its prognostic implications await further studies.

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The antiphospholipid syndrome (APS) is characterized by the presence of pathogenic autoantibodies against β2-glycoprotein-I (β2GPI). The factors causing production of anti-β2GPI remain unidentified, but an association with infectious agents has been reported. Recently, we identified a hexapeptide (TLRVYK) that is recognized specifically by a pathogenic anti-β2GPI mAb. In the present study we evaluated the APS-related pathogenic potential of microbial pathogens carrying sequences related to this hexapeptide. Mice immunized with a panel of microbial preparations were studied for the development of anti-β2GPI autoantibodies. IgG specific to the TLRVYK peptide were affinity purified from the immunized mice and passively infused intravenously into naive mice at day 0 of pregnancy. APS parameters were evaluated in the infused mice on day 15 of pregnancy. Following immunization, high titers of antipeptide [TLRVYK] anti-β2GPI Ab's were observed in mice immunized with Haemophilus influenzae, Neisseria gonorrhoeae, or tetanus toxoid. The specificity of binding to the corresponding target molecules was confirmed by competition and immunoblot assays. Naive mice infused with the affinity-purified antipeptide Ab's had significant thrombocytopenia, prolonged activated partial thromboplastin time and elevated percentage of fetal loss, similar to a control group of mice immunized with a pathogenic anti-β2GPI mAb. Our study establishes a mechanism of molecular mimicry in experimental APS, demonstrating that bacterial peptides homologous with β2GPI induce pathogenic anti-β2GPI Ab's along with APS manifestations.

Based on the essential involvement of NF-kappaB in immune and inflammatory responses and its apoptosis-rescue function in normal and malignant cells, inhibitors of this transcription factor are potential therapeutics for the treatment of a wide range of diseases, from bronchial asthma to cancer. Yet, given the essential function of NF-kappaB in the embryonic liver, it is important to determine its necessity in the liver beyond embryogenesis. NF-kappaB is normally retained in the cytoplasm by its inhibitor IkappaB, which is eliminated upon cell stimulation through phosphorylation-dependent ubiquitin degradation. Here, we directed a degradation-resistant IkappaBalpha transgene to mouse hepatocytes in an inducible manner and showed substantial tissue specificity using various means, including a new method for live-animal imaging. Transgene expression resulted in obstruction of NF-kappaB activation, yet produced no signs of liver dysfunction, even when implemented over 15 months. However, the transgene-expressing mice were very vulnerable both to a severe immune challenge and to a systemic bacterial infection. Despite having intact immunocytes and inflammatory cells, these mice were unable to clear Listeria monocytogenes from the liver and succumbed to sepsis. These findings indicate the essential function of the hepatocyte through NF-kappaB activation in certain systemic infections, possibly by coordinating innate immunity in the liver.