Blocking Tumor-Educated MSC Paracrine Activity Halts Osteosarcoma Progression

Purpose: Human osteosarcoma is a genetically heterogeneous bone malignancy with poor prognosis despite the employment of aggressive chemotherapy regimens. Because druggable driver mutations have not been established, dissecting the interactions between osteosarcoma cells and supporting stroma may provide insights into novel therapeutic targets.Experimental Design: By using a bioluminescent orthotopic xenograft mouse model of osteosarcoma, we evaluated the effect of tumor extracellular vesicle (EV)-educated mesenchymal stem cells (TEMSC) on osteosarcoma progression. Characterization and functional studies were designed to assess the mechanisms underlying MSC education. Independent series of tissue specimens were analyzed to corroborate the preclinical findings, and the composition of patient serum EVs was analyzed after isolation with size-exclusion chromatography.Results: We show that EVs secreted by highly malignant osteosarcoma cells selectively incorporate a membrane-associated form of TGF\u3b2, which induces proinflammatory IL6 production by MSCs. TEMSCs promote tumor growth, accompanied with intratumor STAT3 activation and lung metastasis formation, which was not observed with control MSCs. Importantly, intravenous administration of the anti-IL6 receptor antibody tocilizumab abrogated the tumor-promoting effects of TEMSCs. RNA-seq analysis of human osteosarcoma tissues revealed a distinct TGF\u3b2-induced prometastatic gene signature. Tissue microarray immunostaining indicated active STAT3 signaling in human osteosarcoma, consistent with the observations in TEMSC-treated mice. Finally, we isolated pure populations of EVs from serum and demonstrated that circulating levels of EV-associated TGF\u3b2 are increased in osteosarcoma patients.Conclusions: Collectively, our findings suggest that TEMSCs promote osteosarcoma progression and provide the basis for testing IL6- and TGF\u3b2-blocking agents as new therapeutic options for osteosarcoma patients. Clin Cancer Res; 23(14); 3721-33. \ua92017 AACR

Constitutively active GSK3 beta as a means to bolster dendritic cell functionality in the face of tumor-mediated immune suppression

In patients with cancer, the functionality of Dendritic Cells (DC) is hampered by high levels of tumor-derived suppressive cytokines, which interfere with DC development and maturation. Poor DC development can limit the efficacy of immune checkpoint blockade and in vivo vaccination approaches. Interference in intracellular signaling cascades downstream from the receptors of major tumor-associated suppressive cytokines like IL-10 and IL-6, might improve DC development and activation, and thus enhance immunotherapy efficacy. We performed exploratory functional screens on arrays consisting of >1000 human kinase peptide substrates to identify pathways involved in DC development and its inhibition by IL-10 or IL-6. The resulting alterations in phosphorylation of the kinome substrate profile pointed to glycogen-synthase kinase-3 beta (GSK3 beta) as a pivotal kinase in both DC development and suppression. GSK3 beta inhibition blocked human DC differentiation in vitro, which was accompanied by decreased levels of IL-12p70 secretion, and a reduced capacity for T cell priming. More importantly, adenoviral transduction of monocytes with a constitutively active form of GSK3 beta induced resistance to the suppressive effects of IL-10 and melanoma-derived supernatants alike, resulting in improved DC development, accompanied by up-regulation of co-stimulatory markers, an increase in CD83 expression levels in mature DC, and diminished release of IL-10. Moreover, adenovirus-mediated intratumoral manipulation of this pathway in an in vivo melanoma model resulted in DC activation and recruitment, and in improved immune surveillance and tumor control. We propose the induction of constitutive GSK3 beta activity as a novel therapeutic means to bolster DC functionality in the tumor microenvironment.Peer reviewe

Phase 1 study of everolimus and low-dose oral cyclophosphamide in patients with metastatic renal cell carcinoma

Contains fulltext : 202111.pdf (publisher's version ) (Open Access

Intradermal Delivery of TLR Agonists in a Human Explant Skin Model: Preferential Activation of Migratory Dendritic Cells by Polyribosinic-Polyribocytidylic Acid and Peptidoglycans

TLR agonists are attractive candidate adjuvants for therapeutic cancer vaccines as they can induce a balanced humoral and T cell-mediated immune response. With a dense network of dendritic cells (DCs) and draining lymphatics, the skin provides an ideal portal for vaccine delivery. Beside direct DC activation, TLR agonists may also induce DC activation through triggering the release of inflammatory mediators by accessory cells in the skin microenvironment. Therefore, a human skin explant model was used to explore the in vivo potential of intradermally delivered TLR agonists to stimulate Langerhans cells and dermal DCs in their natural complex tissue environment. The skin-emigrated DCs were phenotyped and analyzed for T cell stimulatory capacity. We report that, of six tested TLR-agonists, the TLR2 and -3 agonists peptidoglycan (PGN) and polyribosinic-polyribocytidylic acid (Poly I:C) were uniquely able to enhance the T cell-priming ability of skin-emigrated DCs, which, in the case of PGN, was accompanied by Th1 polarization. The enhanced priming capacity of Poly I:C-stimulated DCs was associated with a strong upregulation of appropriate costimulatory molecules, including CD70, whereas that of PGN-stimulated DCs was associated with the release of a broad array of proinflammatory cytokines. Transcriptional profiling further supported the notion that the PGN- and Poly I:C-induced effects were mediated through binding to TLR2/nucleotide-binding oligomerization domain 2 and TLR3/MDA5, respectively. These data warrant further exploration of PGN and Poly I:C, alone or in combination, as DC-targeted adjuvants for intradermal cancer vaccines. The Journal of Immunology, 2013, 190:3338-3345

Adenocarcinoma of the Uterine Cervix Shows Impaired Recruitment of cDC1 and CD8+ T Cells and Elevated β-Catenin Activation Compared with Squamous Cell Carcinoma

PURPOSE: Adenocarcinoma of the uterine cervix is the second most common type of cervical cancer after squamous cell carcinoma (SCC). Although both subtypes are treated similarly, patients with adenocarcinoma have a worse prognosis. In this study, immunologic features of the tumor microenvironment in these two subsets were pursued with potential therapeutic implications. EXPERIMENTAL DESIGN: The immune microenvironment of primary tumors and nonmetastatic tumor-draining lymph nodes (TDLN) was compared between patients with cervical adenocarcinoma (n = 16) and SCC (n = 20) by polychromatic flow cytometry and by transcriptional profiling of the primary tumors (n = 299) using publicly available data from The Cancer Genome Atlas (TCGA). RESULTS: Flow cytometric analyses revealed intact T-cell differentiation in TDLNs, but hampered effector T-cell trafficking to the primary tumors in adenocarcinoma, as compared with SCC. TCGA analysis demonstrated higher expression of chemokines involved in effector T-cell homing (CXCL9/10/11) in SCC primary tumors as compared with adenocarcinoma primary tumors, which was highly correlated to a transcriptional signature for type I conventional dendritic cells (cDC1). This was consistent with elevated frequencies of CD141/BDCA3+cDC1 in primary tumor SCC samples relative to adenocarcinoma and correspondingly elevated levels of CXCL9 and CXCL10 in 24-hour ex vivo cultures. Hampered cDC1 recruitment in adenocarcinoma was in turn related to lower transcript levels of cDC1-recruiting chemokines and an elevated β-catenin activation score and was associated with poor overall survival. CONCLUSIONS: Our data have identified an opportunity for the investigation of potentially novel therapeutic interventions in adenocarcinoma of the cervix, that is, β-catenin inhibition and cDC1 mobilization