FKBPL is a critical antiangiogenic regulator of developmental and pathological angiogenesis.

OBJECTIVE: The antitumor effects of FK506-binding protein like (FKBPL) and its extracellular role in angiogenesis are well characterized; however, its role in physiological/developmental angiogenesis and the effect of FKBPL ablation has not been evaluated. This is important as effects of some angiogenic proteins are dosage dependent. Here we evaluate the regulation of FKBPL secretion under angiogenic stimuli, as well as the effect of FKBPL ablation in angiogenesis using mouse and zebrafish models. APPROACH AND RESULTS: FKBPL is secreted maximally by human microvascular endothelial cells and fibroblasts, and this was specifically downregulated by proangiogenic hypoxic signals, but not by the angiogenic cytokines, VEGF or IL8. FKBPL's critical role in angiogenesis was supported by our inability to generate an Fkbpl knockout mouse, with embryonic lethality occurring before E8.5. However, whilst Fkbpl heterozygotic embryos showed some vasculature irregularities, the mice developed normally. In murine angiogenesis models, including the ex vivo aortic ring assay, in vivo sponge assay, and tumor growth assay, Fkbpl(+/-) mice exhibited increased sprouting, enhanced vessel recruitment, and faster tumor growth, respectively, supporting the antiangiogenic function of FKBPL. In zebrafish, knockdown of zFkbpl using morpholinos disrupted the vasculature, and the phenotype was rescued with hFKBPL. Interestingly, this vessel disruption was ineffective when zcd44 was knocked-down, supporting the dependency of zFkbpl on zCd44 in zebrafish. CONCLUSIONS: FKBPL is an important regulator of angiogenesis, having an essential role in murine and zebrafish blood vessel development. Mouse models of angiogenesis demonstrated a proangiogenic phenotype in Fkbpl heterozygotes.

Regulation of Foxp3+ inducible regulatory T cell stability by SOCS2.

Suppressor of cytokine signaling (SOCS) proteins are key regulators of CD4(+) T cell differentiation, and in particular, we have recently shown that SOCS2 inhibits the development of Th2 cells and allergic immune responses. Interestingly, transcriptome analyses have identified SOCS2 as being preferentially expressed in both natural regulatory T cells (Tregs) and inducible Tregs (iTregs); however, the role of SOCS2 in Foxp3(+) Treg function or development has not been fully elucidated. In this study, we show that despite having no effect on natural Treg development or function, SOCS2 is highly expressed in iTregs and required for the stable expression of Foxp3 in iTregs in vitro and in vivo. Indeed, SOCS2-deficient CD4(+) T cells upregulated Foxp3 following in vitro TGF-ß stimulation, but failed to maintain stable expression of Foxp3. Moreover, in vivo generation of iTregs following OVA feeding was impaired in the absence of SOCS2 and could be rescued in the presence of IL-4 neutralizing Ab. Following IL-4 stimulation, SOCS2-deficient Foxp3(+) iTregs secreted elevated IFN-γ and IL-13 levels and displayed enhanced STAT6 phosphorylation. Therefore, we propose that SOCS2 regulates iTreg stability by downregulating IL-4 signaling. Moreover, SOCS2 is essential to maintain the anti-inflammatory phenotype of iTregs by preventing the secretion of proinflammatory cytokines. Collectively, these results suggest that SOCS2 may prevent IL-4-induced Foxp3(+) iTreg instability. Foxp3(+) iTregs are key regulators of immune responses at mucosal surfaces; therefore, this dual role of SOCS2 in both Th2 and Foxp3(+) iTregs reinforces SOCS2 as a potential therapeutic target for Th2-biased diseases.

Clinical and functional characterization of CXCR1/CXCR2 biology in the relapse and radiotherapy resistance of primary PTEN-deficient prostate carcinoma.

Functional impairment of the tumour suppressor PTEN is common in primary prostate cancer and has been linked to relapse post-radiotherapy (post-RT). Pre-clinical modelling supports elevated CXC chemokine signalling as a critical mediator of PTEN-depleted disease progression and therapeutic resistance. We assessed the correlation of PTEN deficiency with CXC chemokine signalling and its association with clinical outcomes. Gene expression analysis characterized a PTEN LOW/CXCR1HIGH/CXCR2HIGH cluster of tumours that associates with earlier time to biochemical recurrence [hazard ratio (HR) 5.87 and 2.65, respectively] and development of systemic metastasis (HR 3.51). In vitro, CXCL signalling was further amplified following exposure of PTEN-deficient prostate cancer cell lines to ionizing radiation (IR). Inhibition of CXCR1/2 signalling in PTEN-depleted cell-based models increased IR sensitivity. In vivo, administration of a CXCR1/2-targeted pepducin (x1/2pal-i3), or CXCR2-specific antagonist (AZD5069), in combination with IR to PTEN-deficient xenografts attenuated tumour growth and progression compared to control or IR alone. Post-mortem analysis confirmed that x1/2pal-i3 administration attenuated IR-induced CXCL signalling and anti-apoptotic protein expression. Interventions targeting CXC chemokine signalling may provide an effective strategy to combine with RT in locally advanced prostate cancer patients with known presence of PTEN-deficient foci.

Protocols for Studies on Genetically Engineered Mouse Models in Prostate Cancer.

Cancer studies have entered an era that is heavily focused on the contribution of the tumor microenvironment. For this reason, in vivo experimentation in an immunodeficient model system is no longer fit for purpose. As a consequence, numerous genetically engineered mouse models (GEMMs) which self-develop tumors have been developed to allow experiments to be performed in a fully immunocompetent setting. One of the most commonly used technologies is Cre-loxP recombination due to its unique ability to control target gene expression in a specified tissue type. However, the major limitation of these models remains the inability to generate sufficient numbers of age-matched mice for a synchronized experimental start date. For this reason, the derivation of cell lines from genetically modified murine prostate tissue is desirable and allows for the generation of syngeneic models via subcutaneous or orthotopic injection.

Oral vaccination: where we are?

As early as 900 years ago, the Bedouins of the Negev desert were reported to kill a rabid dog, roast its liver and feed it to a dog-bitten person for three to five days according to the size and number of bites [1] . In sixteenth century China, physicians routinely prescribed pills made from the fleas collected from sick cows, which purportedly prevented smallpox. One may dismiss the wisdom of the Bedouins or Chinese but the Nobel laureate, Charles Richet, demonstrated in 1900 that feeding raw meat can cure tuberculous dogs - an approach he termed zomotherapy. Despite historical clues indicating the feasibility of oral vaccination, this particular field is notoriously infamous for the abundance of dead-end leads. Today, most commercial vaccines are delivered by injection, which has the principal limitation that recipients do not like needles. In the last few years, there has been a sharp increase in interest in needle-free vaccine delivery; new data emerges almost daily in the literature. So far, there are very few licensed oral vaccines, but many more vaccine candidates are in development. Vaccines delivered orally have the potential to take immunization to a fundamentally new level. In this review, the authors summarize the recent progress in the area of oral vaccines.

Dissolving microneedle delivery of nanoparticle-encapsulated antigen elicits efficient cross-priming and Th1 immune responses by murine Langerhans cells.

Dendritic cells (DCs) of the skin have an important role in skin-mediated immunity capable of promoting potent immune responses. We availed of polymeric dissolving microneedle (MN) arrays laden with nano-encapsulated antigen to specifically target skin DC networks. This modality of immunization represents an economic, efficient, and potent means of antigen delivery directly to skin DCs, which are inefficiently targeted by more conventional immunization routes. Following MN immunization, Langerhans cells (LCs) constituted the major skin DC subset capable of cross-priming antigen-specific CD8+ T cells ex vivo. Although all DC subsets were equally efficient in priming CD4+ T cells, LCs were largely responsible for orchestrating the differentiation of CD4+ IFN-γ- and IL-17-producing effectors. Importantly, depletion of LCs prior to immunization had a profound effect on CD8+ CTL responses in vivo, and vaccinated animals displayed reduced protective anti-tumor and viral immunity. Interestingly, this cross-priming bias was lost following MN immunization with soluble antigen, suggesting that processing and cross-presentation of nano-particulate antigen is favored by LCs. Therefore, these studies highlight the importance of LCs in skin immunization strategies and that targeting of nano-particulate immunogens through dissolvable polymeric MNs potentially provides a promising technological platform for improved vaccination strategies.

Skin dendritic cell targeting via microneedle arrays laden with antigen-encapsulated poly-D,L-lactide-co-glycolide nanoparticles induces efficient antitumor and antiviral immune responses.

The efficacious delivery of antigens to antigen-presenting cells (APCs), in particular, to dendritic cells (DCs), and their subsequent activation remains a significant challenge in the development of effective vaccines. This study highlights the potential of dissolving microneedle (MN) arrays laden with nanoencapsulated antigen to increase vaccine immunogenicity by targeting antigen specifically to contiguous DC networks within the skin. Following in situ uptake, skin-resident DCs were able to deliver antigen-encapsulated poly-d,l-lactide-co-glycolide (PGLA) nanoparticles to cutaneous draining lymph nodes where they subsequently induced significant expansion of antigen-specific T cells. Moreover, we show that antigen-encapsulated nanoparticle vaccination via microneedles generated robust antigen-specific cellular immune responses in mice. This approach provided complete protection in vivo against both the development of antigen-expressing B16 melanoma tumors and a murine model of para-influenza, through the activation of antigen-specific cytotoxic CD8(+) T cells that resulted in efficient clearance of tumors and virus, respectively. In addition, we show promising findings that nanoencapsulation facilitates antigen retention into skin layers and provides antigen stability in microneedles. Therefore, the use of biodegradable polymeric nanoparticles for selective targeting of antigen to skin DC subsets through dissolvable MNs provides a promising technology for improved vaccination efficacy, compliance, and coverage.

Synthetic and natural immunomodulators acting as interferon inducers.

Interferons are first immunomodulatory molecules that have been shown to display a wide range of applications due to their antiviral, antibacterial, antitumor, and inflammatory activities. Natural and recombinant interferons are among most common biologic therapeutics worldwide. Interferon inducers, however, are less known and have been mostly developed and used in former socialist countries. Despite the fact that they are virtually unknown to the Western world, they represent a substantial market share of modern pharmacopoeia in former socialist republics. This review provides a brief description of most popular interferon inducers including Amyxin, Amizon, Anandin, Arbidol, Blasten, Cycloferon, Galavit, Groprinosine, Hepon, Immunoxel, Dzherelo, Kagocel, Larifan, Ligfol, Likopid, Mebavin, MIGI-KLP, V-5 Immunitor, SCV-07, Milife, Neovir, Poludan, Ragocin, Ridostin, Thymogen and Savratz, some of which were in use for several decades for the same clinical indications as for interferons. The variety and choice offered by the pharmaceutical industry behind the former "iron curtain" certainly deserves the appreciation, familiarity and application prospects for medical and research investigators worldwide.