ADAM17 in tumor associated leukocytes regulates inflammatory mediators and promotes mammary tumor formation

Breast Cancer Macrophage Heterogeneity and Self-renewal are Determined by Spatial Localization

Tumor-infiltrating macrophages support critical steps in tumor progression, and their accumulation in the tumor microenvironment (TME) is associated with adverse outcomes and therapeutic resistance across human cancers. In the TME, macrophages adopt diverse phenotypic alterations, giving rise to heterogeneous immune activation states and induction of cell cycle. While the transcriptional profiles of these activation states are well-annotated across human cancers, the underlying signals that regulate macrophage heterogeneity and accumulation remain incompletely understood. Here, we leveraged a novel ex vivo organotypic TME (oTME) model of breast cancer, in vivo murine models, and human samples to map the determinants of functional heterogeneity of TME macrophages. We identified a subset of F4/80highSca-1+ self-renewing macrophages maintained by type-I interferon (IFN) signaling and requiring physical contact with cancer-associated fibroblasts. We discovered that the contact-dependent self-renewal of TME macrophages is mediated via Notch4, and its inhibition abrogated tumor growth of breast and ovarian carcinomas in vivo, as well as lung dissemination in a PDX model of triple-negative breast cancer (TNBC). Through spatial multi-omic profiling of protein markers and transcriptomes, we found that the localization of macrophages further dictates functionally distinct but reversible phenotypes, regardless of their ontogeny. Whereas immune-stimulatory macrophages (CD11C+CD86+) populated the tumor epithelial nests, the stroma-associated macrophages (SAMs) were proliferative, immunosuppressive (Sca-1+CD206+PD-L1+), resistant to CSF-1R depletion, and associated with worse patient outcomes. Notably, following cessation of CSF-1R depletion, macrophages rebounded primarily to the SAM phenotype, which was associated with accelerated growth of mammary tumors. Our work reveals the spatial determinants of macrophage heterogeneity in breast cancer and highlights the disruption of macrophage self-renewal as a potential new therapeutic strategy.

Potential anti-arthritic and anti-inflammatory effects of TNF-α processing inhibitor-1 (TAPI-1): A new approach to the treatment of S. aureus arthritis

Treatment of septic arthritis has become more challenging due to the rise of multidrug resistant strains of Staphylococcus aureus (S. aureus) in recent years. Failure of antibiotic therapies has compelled to initiate the search for new alternatives. This study aimed to unveil the potential anti-arthritic effects of TAPI-1 (TNF-α processing inhibitor-1), an inhibitor that inhibits TACE (TNF-α converting enzyme) mediated release of soluble TNF-α and its receptors along with attenuation of other inflammatory and joint destructive factors responsible for the progression of arthritis. Male Swiss albino mice were inoculated with live S. aureus (5 × 10⁶ cells/mouse) for the development of septic arthritis. TAPI-1 was administered intraperitoneally (10 mg/kg body weight) post S. aureus infection at regular intervals. Throughout the experiment, the severity of arthritis was obtained to be significantly low after TAPI-1 administration. Arthritis index and histopathology confirmed effectiveness of TAPI-1 in mitigating inflammation induced paw swelling and less bone-cartilage destruction in the arthritic knee joints. Lower levels of soluble tumor necrosis factor alpha (sTNF-α) and soluble tumor necrosis factor alpha receptor-1 (sTNFR-1) were detected in the TAPI-1 treated group suggesting TAPI-1 mediated blocking of TACE with subsequent inhibition of TNF-α signalling. Treatment with TAPI-1 lowered the levels of reactive species; matrix metalloproteinase-2 (MMP-2), receptor activator of nuclear factor kappa-B ligand (RANKL) and osteopontin (OPN) denoting less matrix degradation and less osteoclastic bone resorption. Together, this experimental work authenticates TAPI-1 as an alternative therapeutic intervention for the treatment of S. aureus arthritis.

Getting TANned: How the tumor microenvironment drives neutrophil recruitment

The directed migration of neutrophils to sites of injury or infection is mediated by complex networks of chemoattractant-receptor signaling cascades. The recent appreciation of neutrophils as active participants in tumor progression and metastasis has drawn attention to a number of chemokine-receptor systems that may drive their recruitment to tumors. However, the dynamic nature of the tumor microenvironment (TME) along with the phenotypic diversity among tumor-associated neutrophils (TANs) call for a more comprehensive approach to understand neutrophil trafficking to tumors. Here, we review recent advances in understanding how guidance cues underlie neutrophil migration to primary and secondary tumor sites. We also discuss how the presence of other myeloid cells, such as functionally diverse subsets of tumor-associated macrophages (TAMs), can further influence neutrophil accumulation in tumors. Finally, we highlight the importance of hypoxia sensing in localizing TAMs and TANs in the tumor niche and provide a cohesive view on how both myeloid cell types shape TME-associated extracellular matrix organization, which in turn contribute to tumor progression.

Cyclooxygenase-2 in cancer: A review

Cyclooxygenase-2 (COX-2) is frequently expressed in many types of cancers exerting a pleiotropic and multifaceted role in genesis or promotion of carcinogenesis and cancer cell resistance to chemo- and radiotherapy. COX-2 is released by cancer-associated fibroblasts (CAFs), macrophage type 2 (M2) cells, and cancer cells to the tumor microenvironment (TME). COX-2 induces cancer stem cell (CSC)-like activity, and promotes apoptotic resistance, proliferation, angiogenesis, inflammation, invasion, and metastasis of cancer cells. COX-2 mediated hypoxia within the TME along with its positive interactions with YAP1 and antiapoptotic mediators are all in favor of cancer cell resistance to chemotherapeutic drugs. COX-2 exerts most of the functions through its metabolite prostaglandin E2. In some and limited situations, COX-2 may act as an antitumor enzyme. Multiple signals are contributed to the functions of COX-2 on cancer cells or its regulation. Members of mitogen-activated protein kinase (MAPK) family, epidermal growth factor receptor (EGFR), and nuclear factor-κβ are main upstream modulators for COX-2 in cancer cells. COX-2 also has interactions with a number of hormones within the body. Inhibition of COX-2 provides a high possibility to exert therapeutic outcomes in cancer. Administration of COX-2 inhibitors in a preoperative setting could reduce the risk of metastasis in cancer patients. COX-2 inhibition also sensitizes cancer cells to treatments like radio- and chemotherapy. Chemotherapeutic agents adversely induce COX-2 activity. Therefore, choosing an appropriate chemotherapy drugs along with adjustment of the type and does for COX-2 inhibitors based on the type of cancer would be an effective adjuvant strategy for targeting cancer.

MicroRNA-708-3p as a potential therapeutic target via the ADAM17-GATA/STAT3 axis in idiopathic pulmonary fibrosis

MicroRNAs (miRNAs) are important diagnostic markers and therapeutic targets for many diseases. However, the miRNAs that control the pathogenesis of idiopathic pulmonary fibrosis (IPF) and act as potential therapeutic targets for the disease are rarely studied. In the present study, we analyzed the function and regulatory mechanism of microRNA-708-3p (miR-708-3p) and evaluated this marker’s potential as a therapeutic target in IPF. The clinical and biological relevance of fibrogenesis for miR-708-3p was assessed in vivo and in vitro, specifically in matching plasma and tissue samples from 78 patients with IPF. The data showed that the miR-708-3p levels decreased during fibrosis and inversely correlated with IPF. The experiments showed that the decreased miR-708 promoter activity and primer-miR-708(pri-miR-708) expression were the potential causes. By computational analysis, a dual luciferase reporter system, rescue experiments and a Cignal Finder 45-Pathway system with siADAM17 and a miR-708-3p mimic, we identified that miR-708-3p directly regulates its target gene, a disintegrin and metalloproteinase 17 (ADAM17), through a binding site in the 3′ untranslated region, which depends on the GATA/STAT3 signaling pathway. Finally, an miR-708-3p agomir was designed and used to test the therapeutic effects of the miR-708-3p in an animal model. Small-animal imaging technology and other experiments showed that the dynamic image distribution of the miR-708-3p agomir was mainly concentrated in the lungs and could block fibrogenesis. In conclusion, the miR-708-3p–ADAM17 axis aggravates IPF, and miR-708-3p can serve as a potential therapeutic target for IPF.

The Transcriptome of Estrogen-Independent Mammary Growth in Female Mice Reveals That Not All Mammary Glands Are Created Equally

Allometric growth of ducts in the mammary glands (MGs) is widely held to be estrogen dependent. We previously discovered that the dietary fatty acid trans-10, cis-12 conjugated linoleic acid (CLA) stimulates estrogen-independent allometric growth and terminal end bud formation in ovariectomized mice. Given the similar phenotype induced by estrogen and CLA, we investigated the shared and/or divergent mechanisms underlying these changes. We confirmed MG growth induced by CLA is temporally distinct from that elicited by estrogen. We then used RNA sequencing to compare the transcriptome of the MG during similar proliferative and morphological states. Both estrogen and CLA affected the genes involved in proliferation. The transcriptome for estrogen-treated mice included canonical estrogen-induced genes, including Pgr, Areg, and Foxa1. In contrast, their expression was unchanged by CLA. However, CLA, but not estrogen, altered expression of a unique set of inflammation-associated genes, consistent with stromal changes. This CLA-altered signature included increased expression of epidermal growth factor receptor (EGFR) pathway components, consistent with the demonstration that CLA-induced MG growth is EGFR dependent. Our findings highlight a unique role for diet-induced inflammation that underlies estrogen-independent MG development.