Cancer-associated fibroblast-derived Dickkopf-1 suppresses NK cell cytotoxicity in breast cancer

Breast cancer is poorly immunogenic, hence able to evade T cell recognition and respond poorly to immune checkpoint blockade. Breast cancer cells can also evade NK cell-mediated immune surveillance, but the mechanism remains enigmatic. Dickkopf-1 (DKK1) is a Wnt/b-catenin inhibitor, whose levels are increased in breast cancer patients and correlate with reduced overall survival. DKK1 is expressed by cancer-associated fibroblasts (CAFs) in orthotopic breast tumors and patient samples, and at higher levels by bone cells. While bone-derived DKK1 contributes to the systemic elevation of DKK1 in tumor-bearing mice, CAFs represent the primary source of DKK1 at the tumor site. Systemic or bone-specific DKK1 targeting reduces primary tumor growth. Intriguingly, specific deletion of CAF-derived DKK1 also limits breast cancer progression, regardless of its elevated levels in circulation and in the bone. DKK1 does not support tumor proliferation directly but rather suppresses the activation and tumoricidal activity of NK cells. Importantly, increased DKK1 levels and reduced number of cytotoxic NK cells are detected in breast cancer patients with progressive bone metastases compared to those with stable disease. Our findings indicate that DKK1 creates a tumor-supporting environment through the suppression of NK cells in breast cancer.

Determining Endosomal Toll-Like Receptors Gene Expression in NK Cells After Stimulation with Specific Agonists

Poor knowledge is currently available about the biology of Toll-like receptors (TLRs) in natural killer (NK) cells. This is particularly due to the old belief that NK cells are unable to specifically eliminate microbes without presensitization. On the contrary, it has been clearly demonstrated that not only they can be activated through the engagement of Toll-like receptors (TLRs) by microbial molecules, but also that this interaction induces NK cells to release cytokines that, in turn, activate other cells of both innate and adaptive immunity. For this reason, immunotherapy based on local infusion of TLRs ligands is currently considered as a novel potential strategy to treat solid tumors. Here, we provide a protocol to efficiently stimulate NK cells via endosomal TLRs agonists and to determine endosomal TLRs gene expression level. This protocol can be used for in vitro investigation into endosomal TLRs function in NK cells under different conditions.

Abstract LB100: Dickkopf-1 induces breast cancer progression by limiting T cell infiltration into the tumor microenvironment

Activation of Wnt/β-catenin signaling pathway in the tumor cells has been shown to promote cell proliferation and correlate with cancer progression. Therefore, dickkopf-1 (Dkk1), a soluble Wnt/β-catenin inhibitor, has been considered as a tumor suppressor. However, contradicting evidence demonstrated that high levels of circulating Dkk1 correlate with poor prognosis in various cancers. Although Dkk1 is best known to modulate bone remodeling, we recently reported that Dkk1 supports the growth of subcutaneous B16 melanomas by creating an immune-suppressive environment. However, the detailed mechanism by which Dkk1 alters anti-tumor immune responses remains to be elucidated. In this study, we used mice orthotopically injected with hormone-resistant luminal B, ER+ PyMT, EO771 and triple-negative 4T1 cell lines. We find that Dkk1 is upregulated in all models and its neutralization reduces tumor growth. To our surprise, Dkk1 was barely expressed by each tumor lines tested. However, we found elevated expression of Dkk1 in the bone by the osteoblasts (OBs) and in the breast tumor stroma by cancer-associated fibroblasts (CAFs), although at a much lower level compared to the OBs. To address the role of bone-derived versus tumor stroma-derived Dkk1 during tumor progression, we generated mouse models specifically deleting Dkk1 from OBs (OsxCre;Dkk1fl/fl), and from CAFs (Fsp1Cre;Dkk1fl/fl and aSMACreERT2;Dkk1fl/fl). To our surprise, all our mouse models reduced orthotopic PyMT tumor growth significantly, suggesting that Dkk1 could act both systemically and locally to modulate tumor progression. Interestingly, however, deletion of Dkk1 in the bone or in the CAFs did not appear to change the immune composition in the bone marrow, spleen, or at the tumor site. Next, we orthotopically injected PyMT cells into the severely immune-compromised NSG mice treated with anti-Dkk1 or IgG. Strikingly, Dkk1 neutralization did not reduce tumor growth in NSG mice, suggesting that Dkk1 modulates breast cancer growth by altering anti-tumor immune responses. Similar to mice with deletion of Dkk1 in the bone or in the CAFs, Dkk1 neutralization did not alter the percentage of the myeloid and lymphoid cell subsets or the activation status of T cells in bone marrow, spleen, or tumor site compared to IgG control mice. However, by IHC we observed that tumors from anti-Dkk1-treated mice or with deletion of Dkk1 in the CAFs had increased numbers of CD4+ and CD8+ T cells infiltrating the center of tumor mass while these immune populations remained at the edges of the tumors in control mice. In summary, we provide evidence that Dkk1 exerts local and systemic effects to promote tumor progression by modulating the infiltration of immune cells into the TME.

Citation Format: Seunghyun Lee, Biancamaria Ricci, Roberta Faccio. Dickkopf-1 induces breast cancer progression by limiting T cell infiltration into the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB100.

IL-1R8 silencing improves the anti-tumor function of freshly isolated human NK cells

The inhibitory receptor interleukin-1 receptor 8 (IL-1R8) has been recently recognized to be expressed also by human natural killer (NK) cells. This study was aimed to design and optimize IL-1R8 silencing conditions in human NK cells to precisely establish the activity of such receptor in these cells. Electroporation of freshly isolated or IL-2-cultured NK cells with small interfering RNA (siRNA), resulted in a marked, even though variable, IL-1R8-silencing. Although the expression profile revealed downregulation of most genes involved in several intracellular pathways, some genes related to proliferation, expression of some chemokine receptors, antibody-dependent cell cytotoxicity and cytotoxic activity were upregulated in IL-1R8-silenced NK cells. Furthermore, upon IL-15 activation, the majority of genes involved in NK cell function were upregulated in IL-1R8-siRNA—compared with control—siRNA-transfected NK cells. More importantly, in agreement with these findings, the reduction of IL-1R8 gene expression levels resulted in enhanced expression of NK cell activation markers, production of cytokines and chemokines, and cytotoxic activity against several NK cell targets with different susceptibility to NK-mediated lysis. Similar results were obtained following stimulation with IL-18. All together these data, deeply impacting on the main effector functions of human NK cells, can lead to a better understanding of IL-1R8-mediated regulation on these cells and to the design of new strategies for improving NK cell-mediated anti-tumor responses.

Toll-like receptor 8 agonists improve NK-cell function primarily targeting CD56brightCD16− subset

Background

Toll-like receptors (TLRs) are pattern-recognition sensors mainly expressed in innate immune cells that directly recognize conserved pathogen structures (pathogen-associated molecular patterns-PAMPs). Natural killer (NK) cells have been described to express different endosomal TLRs triggered by RNA and DNA sequences derived from both viruses and bacteria. This study was addressed to establish which endosomal TLR could directly mediate NK activation and function after proper stimuli. It was also important to establish the most suitable TLR agonist to be used as adjuvant in tumor vaccines or in combined cancer immunotherapies.

Methods

We assessed endosomal TLR expression in total NK cells by using RT-qPCR and western blotting technique. In some experiments, we purified CD56^brightCD16⁻ and CD56^dimCD16⁺ cells subsets by using NK Cell Isolation Kit Activation marker, cytokine production, CD107a expression and cytotoxicity assay were evaluated by flow cytometry. Cytokine release was quantified by ELISA. NK cells obtained from ovarian ascites underwent the same analyses.

Results

Although the four endosomal TLRs (TLR3, TLR7/8, and TLR9) were uniformly expressed on CD56^brightCD16⁻ and CD56^dimCD16⁺ cell subsets, the TLR7/8 (R848), TLR3 (polyinosinic-polycytidylic acid, Poly I:C) and TLR9 (ODN2395) ligands promoted NK-cell function only in the presence of suboptimal doses of cytokines, including interleukin (IL)-2, IL-12, IL-15, and IL-18, produced in vivo by other environmental cells. We showed that R848 rather than TLR3 and TLR9 agonists primarily activated CD56^brightCD16⁻ NK cells by increasing their proliferation, cytokine production and cytotoxic activity. Moreover, we demonstrated that R848, which usually triggers TLR7 and TLR8 on dendritic cells, macrophages and neutrophils cells, activated CD56^brightCD16⁻ NK-cell subset only via TLR8. Indeed, specific TLR8 but not TLR7 agonists increased cytokine production and cytotoxic activity of CD56^brightCD16⁻ NK cells. Importantly, these activities were also observed in peritoneal NK cells from patients with metastatic ovarian carcinoma, prevalently belonging to the CD56^brightCD16⁻ subset.

Conclusion

These data highlight the potential value of TLR8 in NK cells as a new target for immunotherapy in patients with cancer.

Actions of the NLRP3 and NLRC4 inflammasomes overlap in bone resorption

Overwhelming evidence indicates that excessive stimulation of innate immune receptors of the NOD-like receptor (NLR) family causes significant damage to multiple tissues, yet the role of these proteins in bone metabolism is not well known. Here, we studied the interaction between the NLRP3 and NLRC4 inflammasomes in bone homeostasis and disease. We found that loss of NLRP3 or NLRC4 inflammasome attenuated osteoclast differentiation in vitro. At the tissue level, lack of NLRP3, or NLRC4 to a lesser extent, resulted in higher baseline bone mass compared to wild-type (WT) mice, and conferred protection against LPS-induced inflammatory osteolysis. Bone mass accrual in mutant mice correlated with lower serum IL-1β levels in vivo. Unexpectedly, the phenotype of Nlrp3-deficient mice was reversed upon loss of NLRC4 as bone mass was comparable between WT mice and Nlrp3;Nlrc4 knockout mice. Thus, although bone homeostasis is perturbed to various degrees by the lack of NLRP3 or NLRC4, this tissue appears to function normally upon compound loss of the inflammasomes assembled by these receptors.

Constitutive activation of NF-κB inducing kinase (NIK) in the mesenchymal lineage using Osterix (Sp7)- or Fibroblast-specific protein 1 (S100a4)-Cre drives spontaneous soft tissue sarcoma

Aberrant NF-κB signaling fuels tumor growth in multiple human cancer types including both hematologic and solid malignancies. Chronic elevated alternative NF-κB signaling can be modeled in transgenic mice upon activation of a conditional NF-κB-inducing kinase (NIK) allele lacking the regulatory TRAF3 binding domain (NT3). Here, we report that expression of NT3 in the mesenchymal lineage with Osterix (Osx/Sp7)-Cre or Fibroblast-Specific Protein 1 (FSP1)-Cre caused subcutaneous, soft tissue tumors. These tumors displayed significantly shorter latency and a greater multiple incidence rate in Fsp1-Cre;NT3 compared to Osx-Cre;NT3 mice, regardless of sex. Histological assessment revealed poorly differentiated solid tumors with some spindled patterns, as well as robust RelB immunostaining, confirming activation of alternative NF-κB. Even though NT3 expression also occurs in the osteolineage in Osx-Cre;NT3 mice, we observed no bony lesions. The staining profiles and pattern of Cre expression in the two lines pointed to a mesenchymal tumor origin. Immunohistochemistry revealed that these tumors stain strongly for alpha-smooth muscle actin (αSMA), although vimentin staining was uniform only in Osx-Cre;NT3 tumors. Negative CD45 and S100 immunostains precluded hematopoietic and melanocytic origins, respectively, while positive staining for cytokeratin 19 (CK19), typically associated with epithelia, was found in subpopulations of both tumors. Principal component, differential expression, and gene ontology analyses revealed that NT3 tumors are distinct from normal mesenchymal tissues and are enriched for NF-κB related biological processes. We conclude that constitutive activation of the alternative NF-κB pathway in the mesenchymal lineage drives spontaneous sarcoma and provides a novel mouse model for NF-κB related sarcomas.

Regulation of the Immune System Development by Glucocorticoids and Sex Hormones

Through the release of hormones, the neuro-endocrine system regulates the immune system function promoting adaptation of the organism to the external environment and to intrinsic physiological changes. Glucocorticoids (GCs) and sex hormones not only regulate immune responses, but also control the hematopoietic stem cell (HSC) differentiation and subsequent maturation of immune cell subsets. During the development of an organism, this regulation has long-term consequences. Indeed, the effects of GC exposure during the perinatal period become evident in the adulthood. Analogously, in the context of HSC transplantation (HSCT), the immune system development starts de novo from the donor HSCs. In this review, we summarize the effects of GCs and sex hormones on the regulation of HSC, as well as of adaptive and innate immune cells. Moreover, we discuss the short and long-term implications on hematopoiesis of sex steroid ablation and synthetic GC administration upon HSCT.

Multi-tissue single-cell analysis deconstructs the complex programs of mouse natural killer and type 1 innate lymphoid cells in tissues and circulation

Natural killer (NK) cells and type 1 innate lymphoid cells (ILC1s) are heterogenous innate lymphocytes broadly defined in mice as Lin^-NK1.1⁺NKp46⁺ cells that express the transcription factor T-BET and produce interferon-γ. The ILC1 definition primarily stems from studies on liver and small intestinal populations. However, NK1.1⁺NKp46⁺ cells in the salivary glands, uterus, adipose, and other tissues exhibit nonuniform programs that differ from those of liver or intestinal ILC1s or NK cells. Here, we performed single-cell RNA sequencing on murine NK1.1⁺NKp46⁺ cells from blood, spleen, various tissues, and solid tumors. We identified gene expression programs of tissue-specific ILC1s, tissue-specific NK cells, and non-tissue-specific populations in blood, spleen, and other tissues largely corresponding to circulating cells. Moreover, we found that circulating NK cell programs were reshaped in tumor-bearing mice. Core programs of circulating and tumor NK cells paralleled conserved human NK cells signatures, advancing our understanding of the human NK-ILC1 spectrum.

TREM2 Modulation Remodels the Tumor Myeloid Landscape Enhancing Anti-PD-1 Immunotherapy

Checkpoint immunotherapy unleashes T cell control of tumors, but is undermined by immunosuppressive myeloid cells. TREM2 is a myeloid receptor that transmits intracellular signals that sustain microglial responses during Alzheimer's disease. TREM2 is also expressed by tumor-infiltrating macrophages. Here, we found that Trem2^-/- mice are more resistant to growth of various cancers than wild-type mice and are more responsive to anti-PD-1 immunotherapy. Furthermore, treatment with anti-TREM2 mAb curbed tumor growth and fostered regression when combined with anti-PD-1. scRNA-seq revealed that both TREM2 deletion and anti-TREM2 are associated with scant MRC1⁺ and CX₃CR1⁺ macrophages in the tumor infiltrate, paralleled by expansion of myeloid subsets expressing immunostimulatory molecules that promote improved T cell responses. TREM2 was expressed in tumor macrophages in over 200 human cancer cases and inversely correlated with prolonged survival for two types of cancer. Thus, TREM2 might be targeted to modify tumor myeloid infiltrates and augment checkpoint immunotherapy.

Osterix-Cre marks distinct subsets of CD45- and CD45+ stromal populations in extra-skeletal tumors with pro-tumorigenic characteristics

Cancer-associated fibroblasts (CAFs) are a heterogeneous population of mesenchymal cells supporting tumor progression, whose origin remains to be fully elucidated. Osterix (Osx) is a marker of osteogenic differentiation, expressed in skeletal progenitor stem cells and bone-forming osteoblasts. We report Osx expression in CAFs and by using Osx-cre;TdTomato reporter mice we confirm the presence and pro-tumorigenic function of TdTOSX+ cells in extra-skeletal tumors. Surprisingly, only a minority of TdTOSX+ cells expresses fibroblast and osteogenic markers. The majority of TdTOSX+ cells express the hematopoietic marker CD45, have a genetic and phenotypic profile resembling that of tumor infiltrating myeloid and lymphoid populations, but with higher expression of lymphocytic immune suppressive genes. We find Osx transcript and Osx protein expression early during hematopoiesis, in subsets of hematopoietic stem cells and multipotent progenitor populations. Our results indicate that Osx marks distinct tumor promoting CD45- and CD45+ populations and challenge the dogma that Osx is expressed exclusively in cells of mesenchymal origin.

Therapy-Induced Senescence Drives Bone Loss

Chemotherapy is important for cancer treatment, however, toxicities limit its use. While great strides have been made to ameliorate the acute toxicities induced by chemotherapy, long-term comorbidities including bone loss remain a significant problem. Chemotherapy-driven estrogen loss is postulated to drive bone loss, but significant data suggests the existence of an estrogen-independent mechanism of bone loss. Using clinically relevant mouse models, we showed that senescence and its senescence-associated secretory phenotype (SASP) contribute to chemotherapy-induced bone loss that can be rescued by depleting senescent cells. Chemotherapy-induced SASP could be limited by targeting the p38MAPK-MK2 pathway, which resulted in preservation of bone integrity in chemotherapy-treated mice. These results transform our understanding of chemotherapy-induced bone loss by identifying senescent cells as major drivers of bone loss and the p38MAPK-MK2 axis as a putative therapeutic target that can preserve bone and improve a cancer survivor's quality of life. SIGNIFICANCE: Senescence drives chemotherapy-induced bone loss that is rescued by p38MAPK or MK2 inhibitors. These findings may lead to treatments for therapy-induced bone loss, significantly increasing quality of life for cancer survivors.

Local pesticide use intensity conditions landscape effects on biological pest control

Complex landscapes including semi-natural habitats are expected to favour natural enemies thereby enhancing natural pest biocontrol in crops. However, when considering a large number of situations, the response of natural biocontrol to landscape properties is globally inconsistent, a possible explanation being that local agricultural practices counteract landscape effects. In this study, along a crossed gradient of pesticide use intensity and landscape simplification, we analysed the interactive effects of landscape characteristics and local pesticide use intensity on natural biocontrol. During 3 years, using a set of sentinel prey (weed seeds, aphids and Lepidoptera eggs), biocontrol was estimated in 80 commercial fields located in four contrasted regions in France. For all types of prey excepted weed seeds, the predation rate was influenced by interactions between landscape characteristics and local pesticide use intensity. Proportion of meadow and length of interface between woods and crops had a positive effect on biocontrol of aphids where local pesticide use intensity was low but had a negative effect elsewhere. Moreover, the landscape proportion of suitable habitats for crop pests decreased the predation of sentinel prey, irrespectively of the local pesticide use intensity for weed seeds, but only in fields with low pesticide use for Lepidoptera eggs. These results show that high local pesticide use can counteract the positive expected effects of semi-natural habitats, but also that the necessary pesticide use reduction should be associated with semi-natural habitat enhancement to guarantee an effective natural biocontrol.

Bone matrix components activate the NLRP3 inflammasome and promote osteoclast differentiation

The NLRP3 inflammasome senses a variety of signals referred to as danger associated molecular patterns (DAMPs), including those triggered by crystalline particulates or degradation products of extracellular matrix. Since some DAMPs confer tissue-specific activation of the inflammasomes, we tested the hypothesis that bone matrix components function as DAMPs for the NLRP3 inflammasome and regulate osteoclast differentiation. Indeed, bone particles cause exuberant osteoclastogenesis in the presence of RANKL, a response that correlates with NLRP3 abundance and the state of inflammasome activation. To determine the relevance of these findings to bone homeostasis, we studied the impact of Nlrp3 deficiency on bone using pre-clinical mouse models of high bone turnover, including estrogen deficiency and sustained exposure to parathyroid hormone or RANKL. Despite comparable baseline indices of bone mass, bone loss caused by hormonal or RANKL perturbations is significantly reduced in Nlrp3 deficient than in wild type mice. Consistent with the notion that osteolysis releases DAMPs from bone matrix, pharmacologic inhibition of bone resorption by zoledronate attenuates inflammasome activation in mice. Thus, signals originating from bone matrix activate the NLRP3 inflammasome in the osteoclast lineage, and may represent a bone-restricted positive feedback mechanism that amplifies bone resorption in pathologic conditions of accelerated bone turnover.

PARP inhibitors enhance replication stress and cause mitotic catastrophe in MYCN-dependent neuroblastoma

High-risk and MYCN-amplified neuroblastomas are among the most aggressive pediatric tumors. Despite intense multimodality therapies, about 50% of these patients succumb to their disease, making the search for effective therapies an absolute priority. Due to the important functions of poly (ADP-ribose) polymerases, PARP inhibitors have entered the clinical settings for cancer treatment and are being exploited in a variety of preclinical studies and clinical trials. PARP inhibitors based combination schemes have also been tested in neuroblastoma preclinical models with encouraging results. However, the expression of PARP enzymes in human neuroblastoma and the biological consequences of their inhibition remained largely unexplored. Here, we show that high PARP1 and PARP2 expression is significantly associated with high-risk neuroblastoma cases and poor survival, highlighting its previously unrecognized prognostic value for human neuroblastoma. In vitro, PARP1 and 2 are abundant in MYCN amplified and MYCN-overexpressing cells. In this context, PARP inhibitors with high 'PARP trapping' potency, such as olaparib or talazoparib, yield DNA damage and cell death preceded by intense signs of replication stress. Notwithstanding the activation of a CHK1-CDC25A replication stress response, PARP-inhibited MYCN amplified and overexpressing cells fail to sustain a prolonged checkpoint and progress through mitosis in the presence of damaged DNA, eventually undergoing mitotic catastrophe. CHK1-targeted inhibition of the replication stress checkpoint exacerbated this phenotype. These data highlight a novel route for cell death induction by PARP inhibitors and support their introduction, together with CHK1 inhibitors, in therapeutic approaches for neuroblastomas with high MYC(N) activity.

p38 MAPK differentially controls NK activating ligands at transcriptional and post-transcriptional level on multiple myeloma cells

The mechanisms that regulate the expression of the NKG2D and DNAM-1 activating ligands are only partially known, but it is now widely established that their expression is finely regulated at transcriptional, post-transcriptional and post-translational level, and involve numerous stress pathways depending on the type of ligand, stressor, and cell context. We show that treatment of Multiple Myeloma (MM) cells with sub-lethal doses of Vincristine (VCR), an anticancer drug that inhibits the assembly of microtubules, stimulates the expression of NKG2D and DNAM-1 activating ligands, rendering these cells more susceptible to NK cell-mediated killing. Herein, we focused our attention on the identification of the signaling pathways leading to de novo surface expression of ULBP-1, and to MICA and PVR upregulation on VCR-treated MM cells, both at protein and mRNA levels. We found that p38MAPK differentially regulates drug-dependent ligand upregulation at transcriptional and post-transcriptional level. More specifically, we observed that ULBP-1 expression is attributable to both increased transcriptional activity mediated by ATM-dependent p53 activation, and enhanced mRNA stability; while the p38-activated E2F1 transcription factor regulates MICA and PVR mRNA expression. All together, our findings reveal a previously unrecognized activity of VCR as anticancer agent, and indicate that in addition to its established ability to arrest cell growth, VCR can also modulate the expression of NKG2D and DNAM-1 activating ligand on tumor cells and thus promoting NK cell-mediated immunosurveillance.

Natural killer cell recognition of in vivo drug-induced senescent multiple myeloma cells

Recognition of tumor cells by the immune system is a key step in cancer eradication. Melphalan is an alkylating agent routinely used in the treatment of patients with multiple myeloma (MM), but at therapeutic doses it leads to an immunosuppressive state due to lymphopenia. Here, we used a mouse model of MM to investigate the ability of in vivo treatment with low doses of melphalan to modulate natural killer (NK) cell activity, which have been shown to play a major role in the control of MM growth. Melphalan treatment was able to enhance the surface expression of the stress-induced NKG2D ligands RAE-1 and MULT-1, and of the DNAM-1 ligand PVR (CD155) on MM cells, leading to better tumor cell recognition and killing by NK cells, as highlighted by NK cell increased degranulation triggered by melphalan-treated tumor cells. Remarkably, NK cell population was not affected by the melphalan dose used, but rather displayed activation features as indicated by CD107a and CD69 expression. Furthermore, we showed that low doses of melphalan fail to induce tumor cell apoptosis, but promote the in vivo establishment of a senescent tumor cell population, harboring high levels of the stress-induced ligands RAE-1 and PVR. Taken together our data support the concept of using chemotherapy in order to boost antitumor innate immune responses and report the possibility to induce cellular senescence of tumor cells in vivo.

Dickkopf-related protein 1 (Dkk1) regulates the accumulation and function of myeloid derived suppressor cells in cancer

Tumor-stroma interactions contribute to tumorigenesis. Tumor cells can educate the stroma at primary and distant sites to facilitate the recruitment of heterogeneous populations of immature myeloid cells, known as myeloid-derived suppressor cells (MDSCs). MDSCs suppress T cell responses and promote tumor proliferation. One outstanding question is how the local and distant stroma modulate MDSCs during tumor progression. Down-regulation of β-catenin is critical for MDSC accumulation and immune suppressive functions in mice and humans. Here, we demonstrate that stroma-derived Dickkopf-1 (Dkk1) targets β-catenin in MDSCs, thus exerting immune suppressive effects during tumor progression. Mice bearing extraskeletal tumors show significantly elevated levels of Dkk1 in bone microenvironment relative to tumor site. Strikingly, Dkk1 neutralization decreases tumor growth and MDSC numbers by rescuing β-catenin in these cells and restores T cell recruitment at the tumor site. Recombinant Dkk1 suppresses β-catenin target genes in MDSCs from mice and humans and anti-Dkk1 loses its antitumor effects in mice lacking β-catenin in myeloid cells or after depletion of MDSCs, demonstrating that Dkk1 directly targets MDSCs. Furthermore, we find a correlation between CD15(+) myeloid cells and Dkk1 in pancreatic cancer patients. We establish a novel immunomodulatory role for Dkk1 in regulating tumor-induced immune suppression via targeting β-catenin in MDSCs.

The MRN complex is transcriptionally regulated by MYCN during neural cell proliferation to control replication stress

The MRE11/RAD50/NBS1 (MRN) complex is a major sensor of DNA double strand breaks, whose role in controlling faithful DNA replication and preventing replication stress is also emerging. Inactivation of the MRN complex invariably leads to developmental and/or degenerative neuronal defects, the pathogenesis of which still remains poorly understood. In particular, NBS1 gene mutations are associated with microcephaly and strongly impaired cerebellar development, both in humans and in the mouse model. These phenotypes strikingly overlap those induced by inactivation of MYCN, an essential promoter of the expansion of neuronal stem and progenitor cells, suggesting that MYCN and the MRN complex might be connected on a unique pathway essential for the safe expansion of neuronal cells. Here, we show that MYCN transcriptionally controls the expression of each component of the MRN complex. By genetic and pharmacological inhibition of the MRN complex in a MYCN overexpression model and in the more physiological context of the Hedgehog-dependent expansion of primary cerebellar granule progenitor cells, we also show that the MRN complex is required for MYCN-dependent proliferation. Indeed, its inhibition resulted in DNA damage, activation of a DNA damage response, and cell death in a MYCN- and replication-dependent manner. Our data indicate the MRN complex is essential to restrain MYCN-induced replication stress during neural cell proliferation and support the hypothesis that replication-born DNA damage is responsible for the neuronal defects associated with MRN dysfunctions.

New Indole Tubulin Assembly Inhibitors Cause Stable Arrest of Mitotic Progression, Enhanced Stimulation of Natural Killer Cell Cytotoxic Activity, and Repression of Hedgehog-Dependent Cancer

We designed 39 new 2-phenylindole derivatives as potential anticancer agents bearing the 3,4,5-trimethoxyphenyl moiety with a sulfur, ketone, or methylene bridging group at position 3 of the indole and with halogen or methoxy substituent(s) at positions 4-7. Compounds 33 and 44 strongly inhibited the growth of the P-glycoprotein-overexpressing multi-drug-resistant cell lines NCI/ADR-RES and Messa/Dx5. At 10 nM, 33 and 44 stimulated the cytotoxic activity of NK cells. At 20-50 nM, 33 and 44 arrested >80% of HeLa cells in the G2/M phase of the cell cycle, with stable arrest of mitotic progression. Cell cycle arrest was followed by cell death. Indoles 33, 44, and 81 showed strong inhibition of the SAG-induced Hedgehog signaling activation in NIH3T3 Shh-Light II cells with IC50 values of 19, 72, and 38 nM, respectively. Compounds of this class potently inhibited tubulin polymerization and cancer cell growth, including stimulation of natural killer cell cytotoxic activity and repression of Hedgehog-dependent cancer.

Nitric oxide donors increase PVR/CD155 DNAM-1 ligand expression in multiple myeloma cells: role of DNA damage response activation

Background

DNAX accessory molecule-1 (DNAM-1) is an activating receptor constitutively expressed by macrophages/dendritic cells and by T lymphocytes and Natural Killer (NK) cells, having an important role in anticancer responses; in this regard, combination therapies able to enhance the expression of DNAM-1 ligands on tumor cells are of therapeutic interest. In this study, we investigated the effect of different nitric oxide (NO) donors on the expression of the DNAM-1 ligand Poliovirus Receptor/CD155 (PVR/CD155) in multiple myeloma (MM) cells.

Methods

Six MM cell lines, SKO-007(J3), U266, OPM-2, RPMI-8226, ARK and LP1 were used to investigate the activity of different nitric oxide donors [DETA-NO and the NO-releasing prodrugs NCX4040 (NO-aspirin) and JS-K] on the expression of PVR/CD155, using Flow Cytometry and Real-Time PCR. Western-blot and specific inhibitors were employed to investigate the role of soluble guanylyl cyclase/cGMP and activation of the DNA damage response (DDR).

Results

Our results indicate that increased levels of nitric oxide can upregulate PVR/CD155 cell surface and mRNA expression in MM cells; in addition, exposure to nitric oxide donors renders myeloma cells more efficient to activate NK cell degranulation and enhances their ability to trigger NK cell-mediated cytotoxicity. We found that activation of the soluble guanylyl cyclase and increased cGMP concentrations by nitric oxide is not involved in the up-regulation of ligand expression. On the contrary, treatment of MM cells with nitric oxide donors correlated with the activation of a DNA damage response pathway and inhibition of the ATM /ATR/Chk1/2 kinase activities by specific inhibitors significantly abrogates up-regulation.

Conclusions

The present study provides evidence that regulation of the PVR/CD155 DNAM-1 ligand expression by nitric oxide may represent an additional immune-mediated mechanism and supports the anti-myeloma activity of nitric oxide donors.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1023-5) contains supplementary material, which is available to authorized users.

SUMO1 in human sperm: new targets, role in motility and morphology and relationship with DNA damage

In studies carried out previously, we demonstrated that small ubiquitin-like modifier 1 (SUMO1) is associated with poor sperm motility when evaluated with a protocol that reveals mostly SUMO1-ylated live sperm. Recently, with another protocol, it has been demonstrated that SUMO is expressed in most sperm and is related to poor morphology and motility, suggesting that sumoylation may have multiple roles depending on its localisation and targets. We show herein, by confocal microscopy and co-immunoprecipitation, that dynamin-related protein 1 (DRP1), Ran GTPase-activating protein 1 (RanGAP1) and Topoisomerase IIα, SUMO1 targets in somatic and/or germ cells, are SUMO1-ylated in mature human spermatozoa. DRP1 co-localises with SUMO1 in the mid-piece, whereas RanGAP1 and Topoisomerase IIα in the post-acrosomal region of the head. Both SUMO1 expression and co-localisation with the three proteins were significantly higher in morphologically abnormal sperm, suggesting that sumoylation represents a marker of defective sperm. DRP1 sumoylation at the mid-piece level was higher in the sperm of asthenospermic men. As in somatic cells, DRP1 sumoylation is associated with mitochondrial alterations, this protein may represent the link between SUMO and poor motility. As SUMO pathways are involved in responses to DNA damage, another aim of our study was to investigate the relationship between sumoylation and sperm DNA fragmentation (SDF). By flow cytometry, we demonstrated that SUMO1-ylation and SDF are correlated (r=0.4, P<0.02, n=37) and most sumoylated sperm shows DNA damage in co-localisation analysis. When SDF was induced by stressful conditions (freezing and thawing and oxidative stress), SUMO1-ylation increased. Following freezing and thawing, SUMO1-Topoisomerase IIα co-localisation and co-immunoprecipitation increased, suggesting an involvement in the formation/repair of DNA breakage.

Reactive oxygen species- and DNA damage response-dependent NK cell activating ligand upregulation occurs at transcriptional levels and requires the transcriptional factor E2F1

Increasing evidence indicates that cancer cell stress induced by chemotherapeutic agents promote antitumor immune responses and contribute to their full clinical efficacy. In this article, we identify the signaling events underlying chemotherapy-induced NKG2D and DNAM-1 ligand expression on multiple myeloma (MM) cells. Our findings indicate that sublethal doses of doxorubicin and melphalan initiate a DNA damage response (DDR) controlling ligand upregulation on MM cell lines and patient-derived malignant plasma cells in Chk1/2-dependent and p53-independent manner. Drug-induced MICA and PVR gene expression are transcriptionally regulated and involve DDR-dependent E2F1 transcription factor activity. We also describe the involvement of changes in the redox state in the control of DDR-dependent upregulation of ligand surface expression and gene transcriptional activity by using the antioxidant agent N-acetyl-L-cysteine. Finally, in accordance with much evidence indicating that DDR and oxidative stress are major determinants of cellular senescence, we found that redox-dependent DDR activation upon chemotherapeutic treatment is critical for MM cell entry in premature senescence and is required for the preferential ligand upregulation on senescent cells, which are preferentially killed by NK cells and trigger potent IFN-γ production. We propose immunogenic senescence as a mechanism that promotes the clearance of drug-treated tumor cells by innate effector lymphocytes, including NK cells.

Chemotherapy-elicited upregulation of NKG2D and DNAM-1 ligands as a therapeutic target in multiple myeloma

Malignant cells constitutively express Natural killer group 2, member D (NKG2D) or DNAX Accessory Molecule-1 (DNAM-1) ligands, yet they are often unable to trigger a robust cytotoxic cell response. It may be therapeutically useful to implement strategies aimed at increasing the density of NKG2D and DNAM-1 ligands on the surface of cancer cells, endowing them with the capacity to activate potent antitumor natural killer-cell responses.

Surgical treatment of congenital nasolacrimal duct obstructions in Italy

AIM

The aim of this study to present the surgical treatments performed in Italy for congenital nasolacrimal duct obstruction.

METHODS

This was a retrospective review of the Ministry of Health database for groups aged 0-1 and 1-4 years from 1999 through 2005.

RESULTS

During the study period, a total of 9081 surgical procedures was performed on children 0-4 years of age, 2739 of which on infants under 1 year of age and 6342 on children 1-4 year-old; 8067 (88.8%) of these interventions were represented by nasolacrimal duct probing, 2556 of which in infants under one year of age and 5511 in the 1-4 year age group. Total number of the other surgical techniques was 984, 183 of which among infants younger than one year of age and 801 among children aged 1-4 years. The seven-year mean number of surgical treatments corresponds to a rate of 7.3/10000 live births for infants <1 year old and 4.3/10000 for children aged 1-4 years.

CONCLUSION

When congenital nasolacrimal duct obstructions do not improve spontaneously, probing resulted the more common surgical treatment performed. Our data are related exclusively to infantile inpatients and cases managed on an office basis are not included. Consequently, our figures cannot be considered indicative of the incidence of this pathology in Italy. However, the mean number per 10000 of surgical procedures may represent, in our opinion, a useful indicator for the more severe forms of congenital lacrimal drainage system pathologies.

Penetrating keratoplasty in a newborn: case report and analysis of current surgical trends in Italy

PURPOSE

The aims of this study were to describe bilateral penetrating keratoplasty (PK) in a newborn and to analyze the data of PKs performed in Italy during the 5-year period 1999-2003 in children under 4 years of age.

METHODS

A male newborn had PK at age 3 months and 5 months for near-blindness secondary to severe congenital corneal clouding in both eyes. The infant''s explanted corneas were subjected to histochemical and ultrastructural analyses. Data regarding the number of PKs performed in Italy on 0-4-year-olds were obtained from the Web site of the Italian Ministry of Health.

RESULTS

The postoperative courses were uncomplicated, and 42 months of follow-up data show bilateral graft transparency and substantial improvement in visual acuity despite high-grade myopia and nystagmus. At the ultrastructural level, the main alterations involved the endothelial cells and Descemet membrane. A total of 45 PKs were performed in Italy on patients 0-4 years old from 1999 through 2003; only nine involved babies under 1 year of age.

CONCLUSIONS

In babies with congenital corneal opacities, early PK can reduce severe amblyopia. However, the risk of intra- and postoperative complications in PK is high. Based on the 42-month follow-up, the anatomic and functional results achieved in the current patient are satisfactory despite the presence of nystagmus and postoperative high-grade myopia. This study shows that PKs are rarely performed, in Italy, in children aged 0-4 years, and very few are done during the first year of life.

Analgesic effect of watching TV during venipuncture

AIMS

To assess the analgesic effect of passive or active distraction during venipuncture in children.

METHODS

We studied 69 children aged 7-12 years undergoing venipuncture. The children were randomly divided into three groups: a control group (C) without any distraction procedure, a group (M) in which mothers performed active distraction, and a TV group (TV) in which passive distraction (a TV cartoon) was used. Both mothers and children scored pain after the procedure.

RESULTS

Main pain levels rated by the children were 23.04 (standard deviation (SD) 24.57), 17.39 (SD 21.36), and 8.91 (SD 8.65) for the C, M, and TV groups, respectively. Main pain levels rated by mothers were 21.30 (SD 19.9), 23.04 (SD 18.39), and 12.17 (SD 12.14) for the C, M, and TV groups, respectively. Scores assigned by mothers and children indicated that procedures performed during TV watching were less painful (p<0.05) than control or procedures performed during active distraction.

CONCLUSION

TV watching was more effective than active distraction. This was due either to the emotional participation of the mothers in the active procedure or to the distracting power of television.

[Excision of a schwannoma of the neck: surgical technique]

We present a case of schwannoma of the neck in 49 year old man, symptomatic (paresthesia, cervical mass and dysphagia). After ultrasonography and magnetic resonance of the neck, the patient was operated and excision of the lesion was completely performed. The operation was performed through a cervical approach: the nerves and the vascular and muscular structures were carefully isolated and preserved. The tumour arised from the cervical sympathetic chain. The diagnosis of schwannoma was possible only by histopathologic examen. After 48 months no local recurrence or postoperative complication related to intervention were found. These lesions are uncommon. The identification of the nerve is often difficult until the operation, which is the treatment of choice for the schwannoma.

[Carcinoid tumors of the appendix: when right colectomy?]

Three cases of carcinoid tumour of the appendix (about 0,3 % of all performed appendectomies) has induced the Authors to a review of the literature with the aim to underline the most important biological and pathological findings and the current clinic and therapeutic knowledges. The diagnosis before surgery is rarely made; it is formulated incidentally in most patients by the histological exam during the operation for an appendicitis or during other surgical procedures. The kind of surgical intervention, that is the entity of the surgical demolition, for the treatment of the carcinoid tumours of the appendix is still controversial: appendectomy or right colectomy? It is possible identify, also during the operation for an appendicitis or for other abdominal lesions, criteria that can orient toward a major surgery (size of the neoplasia, subserosal lymphatic invasion, infiltration of the serosa, diffusion in the meso-appendix, location in closeness of the base of the appendix, invasion of the the locoregional lymph nodes, presence of metastases, section ?margins, number of mitoses, cellular pleiomorfism).

[Abdominal emergency surgery in the geriatric patients. Our experience]

The ageing process of general population implies new socio-sanitary problems. Indications for surgical intervention have been modified and enhanced. As far as elective surgery is concerned, the results in elderly subjects do not seem alarming, whereas less satisfactory results have been registered in the patients who underwent an emergency surgical intervention, where nowadays morbidity and mortality still turn out to be high. The Authors have reported their experience of emergency surgery in the geriatric patient. From 1982 to 2002, 718 pts (361 males, 50.3% and 357 females, 49.7%; average age 50 yrs, range 5-92) underwent emergency surgical interventions for abdominal lesions. The pts were subdivided in two groups: group A (> 65 years; 190 pts, 87 males and 103 females; average age 72 yrs, range 66-92); control group B (<65 years; 528 pts, 274 males and 254 females; average age 43 yrs, range 5-65). The results were assessed in terms of morbidity and of the operative and post-operative mortality. Postoperative morbidity proved to be equal to 25.7% (36.3% in the group A, 21.9% in the group B), while intraoperative mortality equal to 0.27%. Postoperative mortality resulted equal to 12.1% (significantly higher in group A pts -- 16.8%- than in group B pts --10.4%). The mortality of the 190 pts belonging to group A was higher in the pts which were presenting respectively 1, 2, 3 or more concomitant diseases. The progressive percentage increase in the number of interventions on elderly pts not only can be due to the demographic increase of old people, but it can also be linked to a change in the surgeon's attitude. At the present time, while elective geriatric surgery implies an acceptable mortality rate (5-8 %), emergency geriatric surgery has not notably modified the prognosis in the last decades and mortality has turned out to be still high (20-30%). We think that it will be possible to obtain better results through geriatric surgery only by reducing emergency interventions as much as possible. In order to do so, it will be important to insist on intervening before the illness, during its natural evolution, requires actions which cannot be postponed. This would lead to positive results not only in terms of mortality and morbidity, which are still considered as the main targets, but also as far as the period of the stay in hospital and costs are concerned.

[Surgical treatment of Crohn's disease complications. Our experience]

Thirty-five patients with Crohn's Disease (CD) were observed: 18 have been treated with medical therapy and 17 (48.6%) underwent to surgical treatment : 1) intolerance to the medical treatment in 5.9% (1 case); 2) local complications in 94.1% (16 cases: 6 stenosis, 2 occlusions, 3 abscesses, 3 fistulas, 1 perforation with peritonitis, 1 case toxic megacolon). The operations have been 19: resective interventions 14 (bowel and/or colon resections), conservative interventions 5. The mortality was 0, the morbidity 35,29%. The incidence of the recurrences in a follow up of 5 year was 42,9%. The Authors conclude that the surgery, indicated for the treatment of complications, can be resective surgery (perforating Crohn disease: fistulas, abscess) or conservative surgery (stenosing Crohn disease: stenosis). Recently the conservative intervention are proposed in the treatment of fistulas and abscesses too, but when the inflammation is mild and in patients that underwent to extensive intestinal resection with risk of short bowel syndrome.

[Role of aortofemoral bypass in the management of unilateral iliac occlusive disease. A follow-up study of 95 patients over a 25-year period]

BACKGROUND

To evaluate the results in a series of patients submitted to aortofemoral bypass due to an unilateral iliac occlusion.

METHODS

Retrospective follow-up study. A total of 95 patients underwent, between 1975 and 2000, aortofemoral bypass because of unilateral iliac occlusion. Most of them (71 patients) were claudicants, Fontaine stage II b, while 12 complained rest pain and 12 suffered ischemic ulcers. Mean follow-up was 128 months (min 2.5 - max 292).

RESULTS

Immediate success was obtained in 88 cases (92.6%), 7 patients were submitted to early redo with restored patency in 6 cases. One month global patency was gained in 98.9% (94 cases). The mean Ankle-brachial index (ABI) improvement was 0.35. At a mean follow-up of 128 months the cumulative patency was 90.8%. During the follow-up, 15 graft occlusions were observed, followed by 9 successful reoperations achieving a 5-year secondary patency of 92.1%. The contralateral iliac artery evolved toward an occlusion in 10 patients (10.5%) during a long time observation (104 months average).

CONCLUSIONS

The unilateral aortofemoral bypass confirmed an excellent long term outcome regarding effectiveness and graft related complications. The low contralateral occlusion rate, in our series, does not justify a more aggressive approach as first surgical option.

Octyl 2-cyanoacrylate tissue adhesive in experimental scleral buckling

PURPOSE

In this experimental study, a sutureless scleral buckling was performed by using a tissue adhesive glue to fixate a silicone band to the sclera. In fact, one of the major risks of traditional scleral buckling is accidental perforation of the bulb, which is more frequent when the sclera is extremely thin as it is in newborns or in eyes with high myopia or scleromalacia.

METHODS

An encircling band of silicone, which is generally anchored to the sclera itself, was sutured in 36 rabbit eyes to three small silastic patches that had been glued to the sclera, at the level of the equator, using octyl 2-cyanoacrylate tissue adhesive. In this manner the anchoring sutures passed through silicone and silicone. The band was tightened to produce buckling of the sclera and its ends were glued together using the same adhesive.

RESULTS

Examination of the eyes from 15 days to 6 months after surgery revealed that the buckle was stable, with no signs of slippage, in 33 eyes. In the remaining 3 (one examined after 15 days, 2 examined after 45 days), one of the three support patches had become detached but there was still no evidence of slippage.

CONCLUSIONS

The stability of the buckle up to six months after surgery suggests that this new adhesive might be used for sutureless surgery in certain types of retinal detachment, such as that associated with stage 4 ROP in which the encircling band has to be removed after several months.

Iris vascular changes in newborns of diabetic mothers

Routine ophthalmic examinations of 600 full-term neonates, including 54 born to mothers with insulin-dependent diabetes mellitus and 12 whose mothers had developed gestational diabetes, revealed significant tortuosity and dilatation of the iris vessels in over half of the infants born to diabetic mothers. Ninety percent of the newborns in the diabetic group presented hypoplasia of the iris stroma and pupil dynamics were altered in 85%. The vessel changes resolved spontaneously within 2 weeks after birth. These changes, which have also been observed in cocaine-intoxicated newborns, should raise the suspicion of adverse vascular effects in the fetus caused by maternal diabetes.