A multi-targeted approach to treating bone metastases.

The treatment of bone-metastatic cancer now takes advantage of the unique biology of this clinical state. The complex interplay between the cancer cells and the bone microenvironment leads to a host of therapeutic targets, with agents in various stages of clinical use or study. Targets include interactions between the cancer cells and osteoclasts, osteoblasts, endothelial cells, stromal cells, hematopoietic progenitor cells, cells of the immune system, and the bone matrix. Efforts at understanding specific mechanisms of drug resistance in the bone are also ongoing. Successful clinical outcomes will be the result of co-targeting and interrupting the various tumor-supportive elements and cooperating pathways at the level of the tumor cell, the primary and metastatic microenvironments, and systemic cancer effects, leading to a "scaled network disruption" to undermine the disease state.

IRF4 expression by lung dendritic cells drives acute but not Trm cell-dependent memory Th2 responses.

Expression of the transcription factor interferon regulatory factor 4 (IRF4) is required for the development of lung conventional DCs type 2 (cDC2s) that elicit Th2 responses, yet how IRF4 functions in lung cDC2s throughout the acute and memory allergic response is not clear. Here, we used a mouse model that loses IRF4 expression after lung cDC2 development to demonstrate that mice with IRF4-deficient DCs display impaired memory responses to allergen. This defect in the memory response was a direct result of ineffective Th2 induction and impaired recruitment of activated effector T cells to the lung after sensitization. IRF4-deficient DCs demonstrated defects in their migration to the draining lymph node and in T cell priming. Finally, T cells primed by IRF4-competent DCs mediated potent memory responses independently of IRF4-expressing DCs, demonstrating that IRF4-expressing DCs are not necessary during the memory response. Thus, IRF4 controlled a program in mature DCs governing Th2 priming and effector responses, but IRF4-expressing DCs were dispensable during tissue-resident memory T cell-dependent memory responses.

Mechanisms of cancer cell metastasis to the bone: a multistep process.

For metastasis to occur, tumor cells must first detach from their tissue of origin. This requires altering both the tissue of origin and the cancer cell. Once detached, cancer cells in circulation must also acquire survival mechanisms. Although many may successfully disseminate, variation exists in the efficiency with which circulating tumor cells home to and invade the bone marrow as metastastic seeds. Disseminated tumor cells that do successfully invade the marrow are secured by cell-cell and cell-extracellular matrix adhesion. However, establishing a foothold in the marrow is not sufficient for disseminated tumor cells to create metastases. A significant latent phase must be overcome by either rescuing cellular proliferation or attenuating micrometastatic mass dormancy programs. Finally, growing metastases fuel osteolysis, osteoblastogenesis and T-cell differentiation, creating a variety of tumor phenotypes. Each step in the metastatic cascade is rich in biological targets and mechanistic pathways.

Pro-lymphangiogenic VEGFR-3 signaling modulates memory T cell responses in allergic airway inflammation.

In allergic airway inflammation, VEGFR-3-mediated lymphangiogenesis occurs in humans and mouse models, yet its immunological roles, particularly in adaptive immunity, are poorly understood. Here, we explored how pro-lymphangiogenic signaling affects the allergic response to house dust mite (HDM). In the acute inflammatory phase, the lungs of mice treated with blocking antibodies against VEGFR-3 (mF4-31C1) displayed less inflammation overall, with dramatically reduced innate and T-cell numbers and reduced inflammatory chemokine levels. However, when inflammation was allowed to resolve and memory recall was induced 2 months later, mice treated with mF4-31C1 as well as VEGF-C/-D knockout models showed exacerbated type 2 memory response to HDM, with increased Th2 cells, eosinophils, type 2 chemokines, and pathological inflammation scores. This was associated with lower CCL21 and decreased TRegs in the lymph nodes. Together, our data imply that VEGFR-3 activation in allergic airways helps to both initiate the acute inflammatory response and regulate the adaptive (memory) response, possibly in part by shifting the TReg/Th2 balance. This introduces new immunomodulatory roles for pro-lymphangiogenic VEGFR-3 signaling in allergic airway inflammation and suggests that airway lymphatics may be a novel target for treating allergic responses.

Adjuvant-free nanofiber vaccine induces in situ lung dendritic cell activation and TH17 responses.

The current paradigm that subunit vaccines require adjuvants to optimally activate innate immunity implies that increased vaccine reactogenicity will invariably be linked to improved immunogenicity. Countering this paradigm, nanoparticulate vaccines have been reported to act as delivery systems for vaccine antigens and induce immunity without the need for exogenous adjuvants or local inflammation; however, the mechanisms underlying the immunogenicity of nanoparticle vaccines are incompletely identified. Here, we show that antigens displayed on self-assembling nanofiber scaffolds and delivered intranasally are presented by CD103+ and CD11b+ lung dendritic cells that up-regulate CD80 and migrate into the draining lymph node (LN). This was accompanied by a nearly exclusive priming and accumulation of antigen-specific TH17 cells occurring independently in both LN and lung. Thus, self-assembling peptide nanofiber vaccines may represent a novel, needle- and adjuvant-free means of eliciting protective immunity against fungal and bacterial infections at skin and mucosal barrier surfaces.

Protection against Staphylococcus aureus bacteremia-induced mortality depends on ILC2s and eosinophils.

The dysregulated, unbalanced immune response of sepsis results in a mortality exceeding 20%, yet recent findings by our group indicate that patients with allergic, type 2-mediated immune diseases are protected from developing sepsis. We evaluated CD4+ Th cell polarization among patients with Staphylococcus aureus bacteremia and confirmed that survivors had a higher percentage of circulating Th2 cells but lower frequencies of Th17 cells and neutrophils early in the course of infection. To establish the mechanism of this protection, we used a mouse model of lethal S. aureus bacteremia and found that intratracheal pretreatment with the type 2-initiating cytokine IL-33 activated pulmonary type 2 innate lymphoid cells (ILC2s) and promoted eosinophilia. In addition, stimulation of type 2 immunity before lethal infection suppressed the pulmonary neutrophilic response to S. aureus. Mice lacking functional ILC2s did not respond to IL-33 and were not protected from lethal bacteremia, but treatment of these mice with the type 2 cytokines IL-5 and IL-13 rescued them from death. Depletion of eosinophils abrogated IL-33-mediated protection, indicating that eosinophilia is also necessary for the survival benefit. Thus, we have identified a potentially novel mechanism by which type 2 immunity can balance dysregulated septic inflammatory responses, thereby clarifying the protective benefit of type 2 immune diseases on sepsis mortality.

IL-33 Drives Monocyte Recruitment to Lung Interstitium through Chemokine Upregulation.

Tissue infiltration by circulating monocytes is a critical step in the initiation and augmentation of type 2 inflammatory responses in the lungs. Our studies demonstrate that IL-33-/- mice have a defect in monocyte extravasation from the vasculature to the lung interstitium during induction of type 2 inflammatory responses. This result suggests that monocyte migration to the lungs is IL-33 dependent, and we found that administration of exogenous recombinant IL-33 is sufficient to restore monocyte localization to the lung interstitium. Further investigation of the effect of early administration of recombinant IL-33 on the lungs identified upregulation of multiple chemokines including the monocyte chemoattractants CCL2, CCL7, and CCL22. Importantly, blockade of G-protein coupled receptor-dependent signaling, and thereby chemokine receptor activity, inhibited IL-33-driven monocyte recruitment. CCR2 deficiency prevented recruitment of monocytes to the lung extravascular space during allergic sensitization, and resulted in reduced eosinophilia after allergen challenge. Thus, IL-33 plays a critical role in the initiation of type 2 inflammatory responses by inducing upregulation of chemokines that promote monocyte recruitment to the lung interstitium.

Disrupting the networks of cancer.

Ecosystems are interactive systems involving communities of species and their abiotic environment. Tumors are ecosystems in which cancer cells act as invasive species interacting with native host cell species in an established microenvironment within the larger host biosphere. At its heart, to study ecology is to study interconnectedness. In ecologic science, an ecologic network is a representation of the biotic interactions in an ecosystem in which species (nodes) are connected by pairwise interactions (links). Ecologic networks and signaling network models have been used to describe and compare the structures of ecosystems. It has been shown that disruption of ecologic networks through the loss of species or disruption of interactions between them can lead to the destruction of the ecosystem. Often, the destruction of a single node or link is not enough to disrupt the entire ecosystem. The more complex the network and its interactions, the more difficult it is to cause the extinction of a species, especially without leveraging other aspects of the ecosystem. Similarly, successful treatment of cancer with a single agent is rarely enough to cure a patient without strategically modifying the support systems conducive to survival of cancer. Cancer cells and the ecologic systems they reside in can be viewed as a series of nested networks. The most effective new paradigms for treatment will be developed through application of scaled network disruption.

Role of transcriptional corepressor CtBP1 in prostate cancer progression.

Transcriptional repressors and corepressors play a critical role in cellular homeostasis and are frequently altered in cancer. C-terminal binding protein 1 (CtBP1), a transcriptional corepressor that regulates the expression of tumor suppressors and genes involved in cell death, is known to play a role in multiple cancers. In this study, we observed the overexpression and mislocalization of CtBP1 in metastatic prostate cancer and demonstrated the functional significance of CtBP1 in prostate cancer progression. Transient and stable knockdown of CtBP1 in prostate cancer cells inhibited their proliferation and invasion. Expression profiling studies of prostate cancer cell lines revealed that multiple tumor suppressor genes are repressed by CtBP1. Furthermore, our studies indicate a role for CtBP1 in conferring radiation resistance to prostate cancer cell lines. In vivo studies using chicken chorioallantoic membrane assay, xenograft studies, and murine metastasis models suggested a role for CtBP1 in prostate tumor growth and metastasis. Taken together, our studies demonstrated that dysregulated expression of CtBP1 plays an important role in prostate cancer progression and may serve as a viable therapeutic target.