Angiogenesis and tumor expansion are associated with extracellular matrix remodeling and involve various proteases such as the plasminogen (Plg)/plasminogen activator (PA) system. Recently, several experimental data have implicated the plasminogen activator inhibitor-1 (PAI-1) in tumor angiogenesis in murine systems. However, little is known about PAI-1 functions in human skin carcinoma progression. By generating immunodeficient mice (in Rag-1-/- or nude background) deleted for PAI-1 gene (PAI-1-/-), we have evaluated the impact of host PAI-1 deficiency on the tumorigenicity of two malignant human skin keratinocyte cell lines HaCaT II-4 and HaCaT A5-RT3 forming low-grade and high-grade carcinomas, respectively. When using the surface transplantation model, angiogenesis and tumor invasion of these two cell lines are strongly reduced in PAI-1-deficient mice as compared to the wild-type control animals. After subcutaneous injection in PAI-1-/- mice, the tumor incidence is reduced for HaCaT II-4 cells, but not for those formed by HaCaT A5-RT3 cells. These data indicate that PAI-1 produced by host cells is an important contributor to earlier stages of human skin carcinoma progression. It exerts its tumor-promoting effect in a tumor stage-dependent manner, but PAI-1 deficiency is not sufficient to prevent neoplastic growth of aggressive tumors of the human skin.

Varicella-zoster virus (VZV) open reading frame 4 (ORF4) encodes a protein with a predicted molecular weight of 51,540 presenting amino acid sequence homology with the immediate-early regulatory protein ICP27 of herpes simplex virus type 1. To investigate the regulatory properties of the ORF4 gene product, we performed a series of transient expression assays in Vero cells, using a plasmid expressing ORF4 as effector and several VZV genes and heterologous genes as targets. The VZV target plasmids contained promoter/regulatory regions from genes belonging to the three putative VZV kinetic classes fused to the chloramphenicol acetyltransferase (CAT) gene. The heterologous target plasmids consisted of promoter/regulatory regions of human cytomegalovirus, Rous sarcoma virus, and human immunodeficiency virus type 1 fused to the reporter gene. These experiments demonstrated that the ORF4 gene product activated expression of ORF62 in a dose-dependent fashion but had no effect on the expression of the three other putative immediate-early genes (ORF4, ORF61, and ORF63). When various amounts of ORF4 were transfected in the presence of early gene promoters, dose-dependent transactivation was evidenced with the thymidine kinase gene (ORF36) and the major DNA-binding protein gene (ORF29) promoters; interestingly, little activity was detected with the promoter of the DNA polymerase gene (ORF28). No activation of late gene expression, represented by the glycoprotein I and glycoprotein II genes, was seen even over a wide range of concentrations of input ORF4 plasmid. Expression of pCMVCAT, pRSVCAT, and pHWVCAT was also stimulated by the ORF4 gene

SUMMARYThe hGH-V gene codes for a variant of human pituitary growth hormone (hGH-N) named placental growth hormone (hPGH). hPGH shares 93% amino acid identity with hGH-N. Until now the hGH-V gene was considered to be exclusively expressed in human placenta, where it replaces maternal circulating hGH-N at the end of pregnancy. In this study we investigated by reverse transcriptasepolymerase chain reaction (RT-PCR) analysis hGH-N, and hGH-V, gene expression in PBMC in men, women and pregnant women. We have demonstrated that hGH-N and hGH-V transcripts are simultaneously produced by PBMC in both men and women as well as pregnant women. The PBMC of a PIT-I-negative woman expressed only the hGH-V transcript, but not the hGH-N one as expected. In conclusion, hGH-V mRNA is expressed by cells other than the syncytiotrophoblast, is not regulated by PIT-I, and may be involved in immune regulation, as is pituitary GH.

No abstract