Project description:SOCS1 plays a role in cellular senescence. Knocking down SOCS1 in senescence induced by the STAT5 oncogene results in senescence bypass by preventing p53 activation Overall design: IMR90 cells were infected with retroviral constructs of either E7 oncoprotein with pWZL ca-STAT5A and pLKO shNTC or E7 with pWZL ca-STAT5A and pLKO shSOCS1
Project description:Multiple secreted factors induce the formation of new blood vessels (angiogenesis). The signal transduction events that orchestrate the numerous cellular activities required for angiogenesis remain incompletely understood. We have shown previously that STAT5 plays a pivotal role in angiogenesis induced by FGF2 and FGF8b. To delineate the signaling pathway downstream of STAT5, we expressed constitutively active (CA) or dominant-negative (DN) mutant STAT5A in mouse brain endothelial cells (EC). We found that the conditioned medium from CA-STAT5A but not from dominant-negative STAT5A overexpressing EC is sufficient to induce EC invasion and tube formation, indicating that STAT5A regulates the secretion of autocrine proangiogenic factors. Conversely, CA-STAT5A-induced conditioned medium had no effect on EC proliferation. Using a comparative genome-wide transcription array screen, we identified the prolactin family member proliferin (PLF1 and PLF4) as a candidate autocrine factor. The CA-STAT5A-dependent transcription and secretion of PLF by EC was confirmed by quantitative RT-PCR and Western blotting, respectively. CA-STAT5A binds to the PLF1 promoter region, suggesting a direct transcriptional regulation. Knockdown of PLF expression by shRNA or by blocking of PLF activity with neutralizing antibodies removed the CA-STAT5A-dependent proangiogenic activity from the conditioned medium of EC. Similarly, the ability of concentrated conditioned medium from CA-STAT5A transfected EC to induce angiogenesis in Matrigel plugs in vivo was abolished when PLF was depleted from the medium. These observations demonstrate a FGF/STAT5/PLF signaling cascade in EC and implicate PLF as autocrine regulator of EC invasion and tube formation.
Project description:Human papillomavirus (HPV) 16 E7 (E7) protein expression in skin promotes epithelial hyperproliferation and transformation to malignancy. Grafts of murine skin expressing E7 protein as a transgene in keratinocytes are not rejected from immunocompetent recipients, whereas grafts expressing ovalbumin (OVA), with or without coexpression of E7 protein, are promptly rejected, demonstrating that E7-associated non-antigen-specific local immunosuppression is not a major determinant of lack of rejection of E7 transgenic skin. To determine whether failure of rejection of E7 skin grafts is due to failure to attract E7-specific effector T cells, E7- and OVA-specific effector CD8+ T cells, activated in vitro, were transferred to animals bearing E7 transgenic skin grafts. Three days after T cell transfer, E7-specific T cells were present in significantly greater numbers than OVA-specific T cells in the grafted skin on animals bearing recently placed or healed E7 grafts, without graft rejection, and also in the ear skin of E7 transgenic animals, without obvious pathology. E7 and OVA-specific T cells were present in lesser numbers in healed E7 grafts than in recently placed grafts and in lesser numbers in recently placed E7 transgenic epidermal grafts without E7-associated hyperproliferation, derived from E7 transgenic mice with a mutated retinoblastoma gene. These data demonstrate that effector T cells are to some extent attracted to E7 transgenic skin specifically by E7 expression, but in large measure non-specifically by the epithelial proliferation associated with E7 expression, and by the local inflammation produced by grafting. Failure of E7 graft rejection was observed despite trafficking of E7-specific effector T cells to E7-expressing epithelium, a finding of consequence for immunotherapy of HPV 16 E7-associated human cancers.
Project description:In order to explore host factor provided by tp53 e7/e7 mutants that supports the colonization of specific microbiota, comparative transcriptomic analyses of intestines of WT vs. tp53 mutants or CV vs. GF conditions at 7 dpf were performed. Overall design: intestinal mRNA profiles of wild type (WT) and tp53 e7/e7 mutant zabrafish at 7 days post fertilization. Zebrafish larvae intestine at 7dpf were dissected and pooled 25 larvae intestine per group using fine pins and forceps manually.
Project description:Cervical cancer is a malignant transformation of keratinocytes initiated by the E7 oncoprotein of human papillomavirus (HPV). These tumors are characterized by keratinocyte hyperproliferation and are often infiltrated with activated CD8 T cells. HPV infection confers changes to gain immunological advantage to promote chronic infection, and these persist with malignant transformation. We investigated the relative importance of the many redundant mechanisms of cytotoxicity used by CD8 T cells to kill keratinocytes expressing HPV E7 oncoprotein using extended-duration time-lapse microscopy that allows examination of cell-to-cell interactions during killing. E7 expression by keratinocytes increased susceptibility to cell-mediated killing. However, while killing of non-transgenic keratinocytes was traditional, perforin-mediated, and caspase-dependent, E7-expression favored killing by perforin-independent, caspase-independent mechanisms. The roles of perforin, TNF?, IFN?, Fas/FasL and PD1/PD-L1 were graded according to target cell survival to produce a hierarchy of killing mechanisms utilized in killing E7-expressing cells. TNF? was essential for perforin-mediated killing of E7-expressing cells, but not perforin-independent killing. IFN? facilitated killing by Fas/FasL interaction, especially in the absence of perforin. Additionally, expression of E7 offered protection from killing by up regulation of PD-L1, Fas and FasL expression on keratinocytes promoting fight-back by target cells, resulting in effector cell death. This study shows that keratinocytes expressing E7 are highly susceptible to killing by CD8 T cells, but utilizing different armamentarium. Down-regulation of CD8 T cell cytotoxicity in HPV-related tumors may be due to suppression by E7-expressing keratinocytes. Immunotherapy for HPV-related cancers may be improved by suppression of PD-L1, or by suppression of FasL.
Project description:Herein, we describe a novel infection model that achieves highly efficient infection of primary keratinocytes with human papillomavirus type 16 (HPV16). This cell culture model does not depend on immortalization and is amenable to extensive genetic analyses. In monolayer cell culture, the early but not late promoter was active and yielded a spliced viral transcript pattern similar to HPV16-immortalized keratinocytes. However, relative levels of the E8^E2 transcript increased over time post infection suggesting the expression of this viral repressor is regulated independently of other early proteins and that it may be important for the shift from the establishment to the maintenance phase of the viral life cycle. Both the early and the late promoter were strongly activated when infected cells were subjected to differentiation by growth in methylcellulose. When grown as organotypic raft cultures, HPV16-infected cells expressed late E1^E4 and L1 proteins and replication foci were detected, suggesting that they supported the completion of the viral life cycle. As a proof of principle that the infection system may be used for genetic dissection of viral factors, we analyzed E1, E6 and E7 translation termination linker mutant virus for establishment of infection and genome maintenance. E1 but not E6 and E7 was essential to establish infection. Furthermore, E6 but not E7 was required for episomal genome maintenance. Primary keratinocytes infected with wild type HPV16 immortalized, whereas keratinocytes infected with E6 and E7 knockout virus began to senesce 25 to 35 days post infection. The novel infection model provides a powerful genetic tool to study the role of viral proteins throughout the viral life cycle but especially for immediate early events and enables us to compare low- and high-risk HPV types in the context of infection.
Project description:Transcriptional profiling of Oct4, Sox2, Lin28 and Nanog (OSLN) reprogramming cell of empty vector compared to HIF2M-NM-1 over-expression at the early stage (day 12) and the late stage(day 30) using fibroblasts MRC5 and IMR90 Eight-condition experiment, empty vector vs. HIF2M-NM-1 over-expression cells, at early stage vs. late stage, and fibroblasts MRC5 vs. IMR90
Project description:We transduced either an empty vector or ARID1B cDNA in IMR90 cells. Cells were selected with puromycin and 6 days after the infection we collected the RNA. ARID1B is a member of the SWI/SNF chromatin-remodeling complex. Our previous experiments showed that knockdown of ARID1B allows cells to bypass cellular senescence. By performing RNA-seq we have shown that ARID1B expression can induce a set of genes involved in the senescence response. Overall design: 2 samples examined: IMR90 cells expressing an empty vector and IMR90 cells expressing ARID1B cDNA
Project description:Tumor suppressors known to date impede cancer growth by arresting the cell cycle or promoting apoptosis. Here we show that unphosphorylated human STAT5A functions as a tumor suppressor capable of repressing multiple oncogenes via heterochromatin formation. Unphosphorylated STAT5A binds to heterochromatin protein 1? (HP1?) and stabilizes heterochromatin. Expressing unphosphorylated STAT5A or HP1? inhibits colon cancer growth in mouse xenograft models. Transcriptome profiling shows that expressing an unphosphorylatable STAT5A has similar effects to overexpressing HP1? in global gene expression. Notably, the majority of the genes commonly repressed by unphosphorylated STAT5A and HP1? have been implicated in cancer development. Finally, down-regulation, somatic mutations, and deletions of STAT5 genes are found in certain human cancers. These results suggest that unphosphorylated STAT5A may epigenetically suppress tumor growth by promoting heterochromatin formation.
Project description:BackgroundAlthough catheter-associated urinary tract infection (CA-UTI) is a major healthcare-related problem worldwide, there is a scarcity of current data from countries with high antimicrobial resistance rates. We aimed to determine the clinical outcomes of patients with CA-UTI compared to those of patients with other sources of complicated urinary tract infection (cUTI), and to assess the impact of antimicrobial resistance. We also aimed to identify the factors influencing 30-day mortality among patients with CA-UTI.MethodsThis was a multicentre, multinational retrospective cohort study including hospitalised adults with cUTI between January 2013 and December 2014 in twenty hospitals from eight countries from southern Europe, Turkey and Israel. The primary endpoint was 30-day mortality. The secondary endpoints were length of hospital stay, symptom improvement after 7?days’ treatment, symptom recurrence at 30?days and readmission 60?days after hospital discharge.ResultsOf the 807 cUTI episodes, 341 (42.2%) were CA-UTIs. The time from catheter insertion to cUTI diagnosis was less than 2?weeks in 44.6% of cases. Overall, 74.5% of cases had hospital or healthcare-acquired CA-UTI. Compared to patients with other cUTI aetiologies, those with CA-UTI had the following characteristics: they were more frequently males, older, admitted for a reason other than cUTI and admitted from a long-term care facility; had higher Charlson’s comorbidity index; and more frequently had polymicrobial infections and multidrug-resistant Gram-negative bacteria (MDR-GNB). Patients with CA-UTI also had significantly higher 30-day mortality rates (15.2% vs 6%) and longer hospital stay (median 14 [interquartile range -IQR- 7-27] days vs 8 [IQR 5–14] days) than patients with cUTI of other sources. After adjusting for confounders, CA-UTI was not independently associated with an increased risk of mortality (odds ratio, 1.40; 95% confidence interval, 0.77–2.54), and neither was the presence of MDR-GNB.ConclusionsCA-UTI was the most frequent source of cUTI, affecting mainly frail patients. The mortality of patients with CA-UTI was high, though this was not directly related to the infection.