Project description:In chronic lymphocytic leukemia (CLL), monocytes and macrophages are skewed toward protumorigenic phenotypes, including the release of tumor-supportive cytokines and the expression of immunosuppressive molecules such as programmed cell death 1 ligand 1 (PD-L1). To understand the mechanism driving protumorigenic skewing in CLL, we evaluated the role of tumor cell–derived exosomes in the cross-talk with monocytes. We carried out RNA sequencing and proteome analyses of CLL-derived exosomes and identified noncoding Y RNA hY4 as a highly abundant RNA species that is enriched in exosomes from plasma of CLL patients compared with healthy donor samples. Transfer of CLL-derived exosomes or hY4 alone to monocytes resulted in key CLL-associated phenotypes, including the release of cytokines, such as C-C motif chemokine ligand 2 (CCL2), CCL4, and interleukin-6, and the expression of PD-L1. These responses were abolished in Toll-like receptor 7 (TLR7)–deficient monocytes, suggesting exosomal hY4 as a driver of TLR7 signaling. Pharmacologic inhibition of endosomal TLR signaling resulted in a substantially reduced activation of monocytes in vitro and attenuated CLL development in vivo. Our results indicate that exosome-mediated transfer of noncoding RNAs to monocytes contributes to cancer-related inflammation and concurrent immune escape via PD-L1 expression.
Project description:Tumor cells modulate host immunity by secreting extracellular vesicles (EV) and soluble factors in circulation. Their interactions with myeloid cells could lead to the generation of myeloid-derived suppressor cells (MDSC), which strongly inhibit the anti-tumor function of T and NK cells. We demonstrated previously that EV derived from mouse and human melanoma cells induced such immunosuppressive activity via upregulating the expression of programmed cell death ligand 1 (PD-L1) on myeloid cells that was dependent on the heat-shock protein 90a (HSP90a) in EV and on the toll-like receptor (TLR) on myeloid cells. Here, we investigated whether soluble HSP90α could convert monocytes into immunosuppressive MDSC. CD14+ monocytes were isolated from the peripheral blood of healthy donors, incubated with human rHSP90α alone or in the presence of inhibitors of TLR4 signaling and analyzed by flow cytometry. Inhibition of T cell proliferation assay was applied to assess immunosuppressive function of rHSP90α-treated monocytes. The concentration of HSP90α was measured by ELISA in plasma of advanced melanoma patients and correlated with clinical outcome. We found that the incubation of monocytes with rHSP90α for 16 h resulted in a strong upregulation of PD-L1 expression, whereas ROS and NO production as well as the expression of arginase-1, adenosine producing ectoenzymes CD39 and CD73 remained unchanged. The PD-L1 upregulation can be blocked by anti-TLR4 antibodies and an NF-κB inhibitor. After longer incubation (for 24h), rHSP90α-treated monocytes downregulated HLA-DR expression and acquired an augmented viability and resistance to apoptosis. Moreover, these monocytes were converted into MDSC indicated by their capacity to inhibit T cell proliferation mediated by TLR4 signaling as well as PD-L1 and indolamin-2,3-Dioxygenase (IDO) 1 expression. Higher levels of HSP90α in plasma of melanoma patients correlated with augmented PD-L1 expression on circulating monocytic (M) MDSC. Furthermore, melanoma patients with high levels of HSP90α displayed shorter progression-free survival (PSF) upon the treatment with immune checkpoint inhibitors (ICI).
Project description:We determined the immune cell composition and their gene expression, by performing single-cell RNA sequencing (scRNA-seq), in anti-PD-L1-treated 2F8cis tumors, a hot and immunoresponsive ovarian murine tumor model, and anti-PD-L1-treated 2F8cis/CA-MSC tumors. We also evaluated the ability of hedgehog inhibitor (HHi) therapy to reverse CA-MSC effects. Adipose-derived mesenchymal stem cells (MSC) were cultured with 2F8cis, an ovarian mouse tumor cell line, to generate cancer-associated MSC (CA-MSC). 2F8cis tumor cell alone or 2F8cis/CA-MSCs co-cultured cells at ratio 1:1 were injected into C57BL/6J mice. Tumor infiltrating CD45+ cells were isolated from anti-PD-L1-treated 2F8cis (Group 1, n=3), anti-PD-L1-treated 2F8cis/CA-MSCs (Group 2, n=3), anti-PD-L1+ IPI-926-treated 2F8cis/CA-MSCs (Group 3, n=3) tumors. Samples were labeled with different TotalSeq oligo-conjugated antibodies and loaded into the Chromium instrument (10x Genomics). The resulting barcoded cDNAs were used to construct libraries. Single-cell cDNA libraries were then processed for RNA sequencing using an Illumina NextSeq-500 platform. Anti-PD-L1-treated 2F8cis/CA-MSC tumors showed a high number of Monocytes and macrophages over-expressing Ccr2 and Tgfbi when compared to anti-PD-L1 responsive 2F8cis tumors. Our results also indicated that IPI-926 restored response to anti-PD-L1 therapy decresing the expression of Ccr2 and Tgfbi both in monocytes and macrophages. Our study represents the first detailed analysis generated by RNA-seq technology of 2F8cis/CA-MSC+ enriched tumor transcriptomes, treated with anti-PDL1 alone or in combination with HHi, and compared with anti-PDL1-treated tumors. The optimized data analysis workflows reported here should provide a framework for comparative investigations of expression profiles.
Project description:PD-L1 suppresses host immunity and promotes tumor growth. We investigated how IFN-? regulates PD-L1 in the ovarian cancer microenvironment. In clinical samples, the number of stromal CTLs in peritoneally disseminated tumors was correlated with PD-L1 expression on the tumor cells, and the lymphocyte number was significantly related to the IFN-? signature score. In mouse models, PD-L1 was induced in peritoneal disseminated tumors, where lymphocytes were prominent, but not in subcutaneous tumors. Depleting IFNGR1 resulted in lower PD-L1 expression and longer survival in peritoneal dissemination model. Injection of IFN-? into subcutaneous tumors increased PD-L1 expression and tumor size, and PD-L1 depletion abrogated tumor growth. These data suggest that IFN-? works as a tumor progressor through PD-L1 induction. The source of IFN-? in ovarian cancer microenvironment and its biological effect to the tumor cells is unclear. The immortalized human ovarian surface epithelial cell line, HOSE-E7/hTERT (HOSE) was treated with IFN-? and expression microarray analysis was performed, and probes showing significantly higher values in IFN-?-added group were termed “IFN-? signature genes (295 probes)”. We then applied this signature to our ovarian cancer microarray data, which included 75 ovarian cancer clinical samples, by means of ss-GSEA. IFN-? signature score was strongly correlated to the number of infiltrating CD4-positive or CD8-positive lymphocytes in the tumors. These data suggest that the IFN-? in the ovarian cancer microenvironment is derived from lymphocytes, and an IFN-?-rich microenvironment is strongly correlated to a lymphocyte-rich microenvironment. Genome-wide transcriptional changes in human ovarian cancer tissue were observed in different tumor immunological microenvironment.
Project description:Tumor cells evade T cell-mediated immunosurveillance via the interaction between programmed death-1 (PD-1) ligand 1 (PD-L1) on tumor cells and PD-1 on T cells. Strategies disrupting PD-1/PD-L1 have shown clinical benefits in various cancers. However, the limited response rate prompts us to investigate the molecular regulation of PD-L1. Here we identify trafficking protein particle complex subunit 4 (TRAPPC4), a major player in vesicular trafficking, as a crucial PD-L1 regulator. TRAPPC4 interacts with PD-L1 in recycling endosomes, promoting RAB11-mediated recycling of PD-L1, and acting as a scaffold between PD-L1 and RAB11, thus replenishing its distribution on the tumor cell surface.
Project description:This is a mathematical model investigating the effects of continuous and intermittent PD-L1 and anti-PD-L1 therapy upon tumor-immune dynamics.
Project description:Maternal immune tolerance toward to the semi-allograft fetus is a prerequisite condition for successful pregnancy. However, the role of maternal monocytes in the induction of systemic immune tolerance is poorly understood. Here we report that placenta facilitates maternal immune tolerance by extruding exosomes. Maternal monocytes were transformed into an immunosuppressive phenotype after taking up exosomes. Mechanistically, PD-L1 was significantly increased in pEXO-educated monocytes via miRNA-29a-3p/PTEN signaling pathway. In addition, pEXO-treated monocytes could increase Treg pool in maternal blood through a direct cell-cell interaction. Moreover, Th1 cytokines, IFNγ and TNF-α, in monocyte-T cell co-culture system were significantly decreased. Together, our results indicated that maternal monocyte is indispensable components in systemic immune tolerance establishment.
Project description:Programmed cell death 1 ligand 1 (PD-L1) is known to suppress immune system and to be an unfavorable prognostic factor in ovarian cancer. The purpose of this study was to elucidate the function of PD-L1 in peritoneal dissemination. Tumor cell lysis by CTLs was attenuated when PD-L1 on tumor cells was overexpressed and promoted when it was silenced. PD-L1 overexpression also inhibited gathering and degranulation of CTLs. Gene expression profile of mouse CTLs caused by PD-L1-overexpressing ovarian cancer was related to human CTLs exhaustion. In mouse ovarian cancer dissemination models, depleting PD-L1 expression on tumor cells resulted in inhibited tumor growth in the peritoneal cavity and prolonged survival. Restoring immune function by inhibiting immune-suppressive factors such as PD-L1 may be a promising therapeutic strategy for peritoneal dissemination. Genome-wide transcriptional changes in OT-1 mouse CD8+ T cells that were co-incubated with OVA peptide-loaded ID8 mouse ovarian cancer cell lines. CTLs from 4 mice were devided into 2 groups, and co-incubated with PD-L1-overexpressed ID8 or PD-L1-depleted ID8.
Project description:Disrupting PD-1/PD-L1 interaction rejuvenates antitumor immunity. Clinical successes by blocking PD-1/PD-L1 binding have grown across wide-ranging cancer histologies, but innate therapy resistance is evident in the majority of treated patients1. Cancer cells can express robust surface levels of PD-L1 to tolerize tumor-specific T cells, but regulation of PD-L1 protein levels in the cancer cell is poorly understood. Quasi-mesenchymal tumor cells up-regulate PD-L1/L2 and induce an immune-suppressive microenvironment, including expansion of M2-like macrophages and regulatory T cells and exclusion of CD8+ T-cell infiltration2. Targeted therapy, including MAPK inhibitor therapy in melanoma, leads to quasi-mesenchymal transitions and resistance3, and both MAPK inhibitor treatment and mesenchymal signatures are associated with innate anti-PD-1 resistance4,5. Here we identify ITCH as an E3 ligase that downregulates tumor cell-surface PD-L1/L2 in PD-L1/L2-high cancer cells, including MAPK inhibitor-resistant melanoma, and suppresses acquired MAPK inhibitor resistance in and only in immune-competent mice. ITCH interacts with and poly-ubiquitinates PD-L1/L2, and ITCH deficiency increases cell-surface PD-L1/L2 expression and reduces T cell activation. Mouse melanoma tumors grow faster with Itch knockdown only in syngeneic hosts but not in immune-deficient mice. MAPK inhibitor therapy induces tumor cell-surface PD-L1 expression in murine melanoma, recapitulating the responses of clinical melanoma3, and this induction is more robust with Itch knockdown. Notably, suppression of ITCH expression first elicits a shift toward an immune-suppressive microenvironment and then accelerates resistance development. These findings collectively identify ITCH as a critical negative regulator of PD-L1 tumor cell-surface expression and provide insights into previously unexplained role of PD-L1 in adaptive resistance to therapy.