Kari Alitalo

Bio: Kari Alitalo is an academic researcher from University of Helsinki. The author has contributed to research in topics: Angiogenesis & Vascular endothelial growth factor C. The author has an hindex of 174, co-authored 817 publications receiving 114231 citations. Previous affiliations of Kari Alitalo include Mount Sinai Hospital, Toronto & Cornell University.

Molecular pathways for lymphangiogenesis and their role in human disease.

Abstract: The lymphatic network functions to return fluid, cells and macromolecules to the circulation. Recent characterization of growth factors that control the growth and development of the lymphatics, and markers which specify lymphatic endothelial cells have enhanced our understanding of this system. Members of the VEGF family of factors are key regulators of these vessels with VEGF-C/VEGF-D and VEGFR-3 being the best validated signalling pathways in lymphangiogenesis. The study of these molecules in various pathologies has shown that they are important in the processes of cancer metastasis and in the formation of lymphoedema. Knowledge of these molecular pathways allows for the generation of modulators of these pathways which could form the basis of novel therapeutic approaches.

Pericellular matrix and cell surface glycoproteins of virus-transformed mouse epithelial cells.

Abstract: Mouse embryo Mus musculus castaneous epithelial cells, transformed with Moloney murine sarcoma virus (MSV) or with ecotropic murine leukemia virus (MuLV), were analyzed for production of pericellular matrix glycoproteins. The nontransformed, MSV-transformed, and MuLV-transformed cells produced fibronectin, laminin, type I collagen, and small amounts of type III collagen when studied by immunofluorescence using specific antibodies. The virus-transformed epithelial cells produced enhanced amounts of fibronectin into their growth media. Nontransformed M. musculus castaneous epithelial cells mainly produced type I collagen, as shown by metabolic labeling and polypeptide analysis. A significant increase in the glycoprotein production was seen by the MuLV-transformed cells, whereas small changes in the collagen production were apparent after MSV transformation. MuLV-transformed cells produced increased amounts of type I collagen and also some collagenous polypeptides that comigrated with procollagen type IV chains. The ratio of the procollagen type I chains deposited in the matrix was altered in transformed cells. Radioactive surface labeling of the cells revealed changes of the high-molecular-weight glycoproteins in both the MSV- and the MuLV-transformed cells. Unlike virus-transformed fibroblastic cells, these transformed epithelial cells deposited and retained connective tissue glycoproteins in their pericellular matrices. The results indicate that viral transformation modulates the pericellular matrix and surface glycoproteins of cultured mouse epithelial cells. The ability of virus-transformed epithelial cells to deposit pericellular matrices is a major difference between them and virus-transformed fibroblastic cells.

Progenitor cell materials and methods

Abstract: Provided are purified and isolated VEGF-C polypeptides capable of binding to at least one of KDR receptor tyrosine kinase (VEGFR-2) and Flt4 receptor tyrosine kinase (VEGFR-3); analogs of such peptides that have VEGF-C-like or VEGF-like biological activities or that are VEGF or VEGF-C inhibitors; polynucleotides encoding the polypeptides; vectors and host cells that embody the polynucleotides; pharmaceutical compositions and diagnostic reagents comprising the polypeptides; and methods of making and using the polypeptides.

Cardiomyocyte-targeted HIF-1α gene therapy inhibits cardiomyocyte apoptosis and cardiac allograft vasculopathy in the rat

Abstract: Background Hypoxia-inducible factor-1 (HIF-1), a key transcription factor in hypoxia, affects a wide range of adaptive cell functions. We examined the kinetics of endogenous HIF-1α during acute and chronic rejection, and the effect of exogenous HIF-1α in chronically rejecting rat cardiac allografts. Methods Heterotopic cardiac transplantations were performed between major MHC-mismatched Dark Agouti and Wistar–Furth rats. Cyclosporine A (CsA) was used to prevent acute rejection in the chronic rejection model. The effect of HIF-1α overexpression was investigated by adeno-assocated virus 2 (AAV2)-mediated gene transfer of a constitutively stabilized form of mouse HIF-1α (AAV-HIF-1α). The analysis of allografts was based on histology, immunohistochemistry and quantitative reverse transcript–polymerase chain reaction (RT-PCR). Results Acute and chronic rejection significantly induced HIF-1α mRNA in rat cardiac allografts when compared with syngeneic controls. Immunohistochemistry localized significantly increased HIF-1α immunoreactivity to vascular smooth muscle cells, vascular endothelial cells, post-capillary venules and graft-infiltrating mononuclear inflammatory cells of the allograft, whereas expression in cardiomyocytes remained unchanged. Regression analysis revealed a linear correlation between the progression of cardiac allograft vasculopathy (CAV) and HIF-1α immunoreactivity in post-capillary venules and graft-infiltrating mononuclear inflammatory cells in chronically rejecting rat cardiac allografts. AAV-HIF-1α enhanced cardiomyocyte HIF-1α production and significantly reduced cardiomyocyte apoptosis and the development of CAV in chronically rejecting rat cardiac allografts. Conclusions We found that acute and chronic rejection increased HIF-1α mRNA and protein levels in rat cardiac allografts. On the other hand, cardiomyocyte-targeted HIF-1α gene transfer inhibited cardiomyocyte apoptosis and the development of CAV, suggesting a novel therapeutic strategy for HIF-1α in cardiac allografts.

Expression of the c-Ha-ras and neu oncogenes in DMBA-induced, anti-estrogen-treated rat mammary tumors.

Abstract: Dimethylbenzanthracene (DMBA)-induced rat mammary tumors were analyzed for the structure and expression of the oncogenes c-Ha-ras and neu and the effects of anti-estrogen treatment. Tumor samples were divided into 3 groups, the first consisting of untreated tumors, the second of anti-estrogen (toremifene)-treated unresponsive (growing) tumors, and the third of toremifene-treated responsive (regressing) tumors. DNA and RNA derived from normal tissues of the same experimental animals were also analyzed. In Southern blot analysis of genomic DNAs, 2 tumors out of 23 contained a new Xbal site in the Ha-ras gene, indicating a point mutation in the second nucleotide of codon 61. Both of these tumors belonged to the group that had not received toremifene. No amplifications of the Ha-ras or the neu genes were observed. Although greatly variable, the levels of Ha-ras mRNA were highest in untreated tumors, lower in toremifene-treated, unresponsive tumors and even lower in toremifene-treated, regressing tumors, corresponding approximately to the levels detected in normal liver and uterus of untreated animals. Expression of the neu mRNA was variable and considerably lower than that of Ha-ras mRNA. It was similar in all 3 groups and somewhat elevated than in several non-malignant control tissues. Localization of c-Ha-ras expression by in situ hybridization revealed a relatively even distribution of the mRNA throughout the mammary tissue. The results suggest that mechanisms other than activation of the c-Ha-ras or neu genes are important for progression and regression of DMBA-induced rat mammary carcinomas.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Inflammation and cancer

Abstract: Recent data have expanded the concept that inflammation is a critical component of tumour progression. Many cancers arise from sites of infection, chronic irritation and inflammation. It is now becoming clear that the tumour microenvironment, which is largely orchestrated by inflammatory cells, is an indispensable participant in the neoplastic process, fostering proliferation, survival and migration. In addition, tumour cells have co-opted some of the signalling molecules of the innate immune system, such as selectins, chemokines and their receptors for invasion, migration and metastasis. These insights are fostering new anti-inflammatory therapeutic approaches to cancer development.

Human breast cancer: correlation of relapse and survival with amplification of the HER-2/neu oncogene

Abstract: The HER-2/neu oncogene is a member of the erbB-like oncogene family, and is related to, but distinct from, the epidermal growth factor receptor. This gene has been shown to be amplified in human breast cancer cell lines. In the current study, alterations of the gene in 189 primary human breast cancers were investigated. HER-2/neu was found to be amplified from 2- to greater than 20-fold in 30% of the tumors. Correlation of gene amplification with several disease parameters was evaluated. Amplification of the HER-2/neu gene was a significant predictor of both overall survival and time to relapse in patients with breast cancer. It retained its significance even when adjustments were made for other known prognostic factors. Moreover, HER-2/neu amplification had greater prognostic value than most currently used prognostic factors, including hormonal-receptor status, in lymph node-positive disease. These data indicate that this gene may play a role in the biologic behavior and/or pathogenesis of human breast cancer.