Project description:Blocking the PD-1/PD-L1 immunosuppressive pathway has shown promise in the treatment of certain cancers including melanoma. This study investigates differences in the gene expression profiles of human melanomas that do or do not display the immunosuppressive protein PD-L1. Further understanding of genes expressed within the tumor microenvironment of PD-L1+ tumors may lead to improved rationally designed treatments. Gene expression profiling was performed on total RNA extracted by laser capture microdissection from 11 archived formalin-fixed paraffin-embedded (FFPE) melanoma specimens, 5 of which were PD-L1 positive and 6 PD-L1 negative. Details of the design, and the gene signatures found are given in the paper associated with this GEO Series: Janis M. Taube, Geoffrey D. Young, Tracee L. McMiller, Shuming Chen, January T. Salas, Theresa S. Pritchard, Haiying Xu, Alan K. Meeker, Jinshui Fan, Chris Cheadle, Alan E. Berger, Drew M. Pardoll, and Suzanne L. Topalian, Differential expression of immune-regulatory genes associated with PD-L1 display in melanoma: implications for PD-1 pathway blockade, Clin Cancer Res 2015, in press.
Project description:Since both endogenous synthesis in tumor cells and bacterial sulfur reduction activities are sources of H2S in colon cancer microenvironment, in addition to using CBS -/+ mice, we also investigated the roles of reducing H2S through adopting a sulfur amino acid restriction diet (SARD) (0.15% methionine and 0% cystine) on immunotherapy (anti-PD-L1) of colon cancer. Tumor bulk sequencing was performed in cecum orthotopic CT26 tumors collected from IgG and anti-PD-L1 treated mice both receiving normal diet and SARD.
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:Anti-PD-L1-based combination immunotherapy has become the first-line treatment for unresectable hepatocellular carcinoma (HCC). However, the objective response rate is lower than 40%, highlighting the need to identify mechanisms of tolerance to immune checkpoint inhibitors and accurate biomarkers of response. Here, we employed next-generation sequencing to analyze HCC samples from 10 patients receiving anti-PD-L1 therapy. Activation of the renin-angiotensin system was elevated in nonresponders compared with responders, and ACE2 expression was significantly downregulated in nonresponders. ACE2 deficiency promoted HCC development and anti-PD-L1 resistance, whereas ACE2 overexpression inhibited HCC progression in immune competent mice. Mass cytometry by time of flight (CyTOF) revealed that ACE2 deficient murine orthotopic tumor tissues featured elevated M2-like tumor-associated macrophages (TAMs), displayed a CCR5+PD-L1+ immunosuppressive phenotype, and exhibited high VEGFα expression. ACE2 downregulated tumor intrinsic CCL5 expression by suppressing NF-κB signaling through the ACE2/angiotensin-(1–7)/Mas receptor axis. The lower CCL5 levels led to reduced activation of the JAK-STAT3 pathway and suppressed PD-L1 and VEGFα expression in macrophages, blocking macrophage infiltration and M2-like polarization. Pharmacological targeting of CCR5 using maraviroc enhanced the tumor suppressive effect of anti-PD-L1 therapy. Together, these findings suggest that activation of the ACE2 axis overcomes the immunosuppressive microenvironment of HCC and may serve as an immunotherapeutic target and predictive biomarker of response to PD-L1 blockade.
Project description:BackgroundAnti-programmed cell death-1(anti-PD1) treatment has shown promising antitumor efficacy in patients with advanced hepatocellular carcinoma (HCC). This study sought to explore the functional significance of programmed death ligand-1 (PD-L1) expression in tumor cells in the tumor microenvironment.MethodsThe mouse liver cancer cell line BNL-MEA was transfected with PD-L1 plasmids and stable clones expressing PD-L1 were selected. An orthotopic HCC model was generated by implanting the cells into the subcapsular space of BALB/c mice. Cell growth features were measured by proliferation assay, colony formation, flow cytometry (in vitro), ultrasonography, and animal survival (in vivo). The changes in T-cell function were examined by cytokine assay, expression of T-cell related genes, and flow cytometry. The efficacy of anti-PD1 therapy was compared between the parental and PD-L1-expressing tumors.ResultsPD-L1 expression did not affect growth characteristics of BNL-MEA cells but downregulated the expression of genes related to T-cell activation in the tumor microenvironment. Co-culture of PD-L1-expressing BNL-MEA cells with CD8+ T cells reduced T-cell proliferation and expression of cytokines IFNγ and TNFα. Tumors with PD-L1 expression showed better response to anti-PD1 therapy and depletion of CD8+ T cells abolished the antitumor effect. The difference in treatment response between parental and PD-L1-expressing tumors disappeared when a combination of anti-PD1 and sorafenib was given.ConclusionsPD-L1 expression in HCC cells may inhibit T-cell function in the liver tumor microenvironment. Anti-PD1 therapy appeared more effective in PD-L1-expressing than nonexpressing tumors, but the difference was diminished by the addition of sorafenib.
Project description:PD-L1 Inhibitor Regulates the miR-33a-5p/PTEN Signaling Pathway and Can Be Targeted to Sensitize Glioblastomas to Radiation. Glioblastoma (GBM) is the most common and lethal brain tumor in adults. Ionizing radiation (IR) is a standard treatment for GBM patients and results in DNA damage. However, the clinical efficacy of IR is limited due to therapeutic resistance. The programmed death ligand 1 (PD-L1) blockade has a shown the potential to increase the efficacy of radiotherapy by inhibiting DNA damage and repair responses. The miR-33a-5p is an essential microRNA that promotes GBM growth and self-renewal. In this study, we investigated whether a PD-L1 inhibitor (a small molecule inhibitor) exerted radio-sensitive effects to impart an anti-tumor function in GBM cells by modulating miR-33a-5p. U87 MG cells and U251 cells were pretreated with PD-L1 inhibitor. The PD-L1 inhibitor-induced radio-sensitivity in these cells was assessed by assaying cellular apoptosis, clonogenic survival assays, and migration. TargetScan and luciferase assay showed that miR-33a-5p targeted the phosphatase and tensin homolog (PTEN) 3' untranslated region. The expression level of PTEN was measured by western blotting, and was also silenced using small interfering RNAs. The levels of DNA damage following radiation was measured by the presence of γ-H2AX foci, cell cycle, and the mRNA of the DNA damage-related genes, BRCA1, NBS1, RAD50, and MRE11. Our results demonstrated that the PD-L1 inhibitor significantly decreased the expression of the target gene, miR-33a-5p. In addition, pretreatment of U87 MG and U251 cells with the PD-L1 inhibitor increased radio-sensitivity, as indicated by increased apoptosis, while decreased survival and migration of GBM cells. Mir-33a-5p overexpression or silencing PTEN in U87 MG and U251 cells significantly attenuated PD-L1 radiosensitive effect. Additionally, PD-L1 inhibitor treatment suppressed the expression of the DNA damage response-related genes, BRCA1, NBS1, RAD50, and MRE11. Our results demonstrated a novel role for the PD-L1 inhibitor in inducing radio- sensitivity in GBM cells, where inhibiting miR-33a-5p, leading to PTEN activated, and inducing DNA damage was crucial for antitumor immunotherapies to treat GBM.
Project description:Blocking the PD-1/PD-L1 immunosuppressive pathway has shown promise in the treatment of certain cancers including melanoma. This study investigates differences in the gene expression profiles of human melanomas that do or do not display the immunosuppressive protein PD-L1. Further understanding of genes expressed within the tumor microenvironment of PD-L1+ tumors may lead to improved rationally designed treatments.
Project description:Although membrane-anchored Pd-l1 has been well-studied for its engagement with PD-1 on T cells to evade anti-tumor immunity, whether Pd-l1 regulate oncogenic signaling pathways in tumor cells remains elusive. In this experiment, to further dissect roles of the K262 residue acetylation for Pd-l1 nuclear function, we profiled RNA expression of WT or K262Q mutant mouse Pd-l1 re-expressed in CT26 KO Pd-l1 cells. Methods: Total RNA fromCT26/Vector, CT26/WT or CT26 Pd-l1 KO cells was purified using Qiagen RNeasy mini kit (Qiagen) according to the manufacturer’s instructions. Library preparation and sequenceing analysis were performed by BGI-Hong Kong Co. Ltd. Conclusions: Our study indicates that Pd-l1 acetylation modification may affect its function in nuclear.