Frequent expression of PD-L1 on circulating breast cancer cells.
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ABSTRACT:
SUBMITTER: Mazel M
PROVIDER: S-EPMC5528721 | biostudies-other | 2015 Nov
REPOSITORIES: biostudies-other
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Project description:BackgroundImmune checkpoint inhibition is effective in several cancers. Expression of programmed death-ligand 1 (PD-L1) on circulating tumor or immune effector cells could provide insights into selection of patients for immune checkpoint inhibition.MethodsWhole blood was collected at serial timepoints from metastatic breast cancer patients and healthy donors for circulating tumor cell (CTC) and platelet PD-L1 analysis with a phycoerythrin-labeled anti-human PD-L1 monoclonal antibody (Biolegend clone 29E.2A3) using the CellSearch® assay. CTC PD-L1 was considered positive if detected on at least 1% of the cells; platelet PD-L1 was considered positive if ≥100 platelets per CellSearch frame expressed PD-L1.ResultsA total of 207 specimens from 124 metastatic breast cancer patients were collected. 52/124 (42%) samples at timepoint-1 (at or close to time of progressive disease) had ≥5 CTC/7.5ml whole blood. Of those, 21 (40%) had positive CTC PD-L1. In addition, platelet PD-L1 expression was observed in 35/124 (28%) at timepoint-1. Platelet PD-L1 was not detected in more than 70 specimens from 12 healthy donors. Platelet PD-L1 was associated with ≥5 CTC/7.5ml whole blood (p = 0.0002), less likely in patients with higher red blood cell counts (OR = 0.72, p<0.001) and a history of smoking tobacco (OR = 0.76, p<0.001). Platelet PD-L1 staining was not associated with tumor marker status, recent procedures or treatments, platelet-affecting drugs, or CTC PD-L1 expression.ConclusionPD-L1 expression was found in metastatic breast cancer patients on both CTC and platelets in an independent fashion. Inter-patient platelet PD-L1 expression was highly heterogeneous suggesting that it is a biological event associated with cancer in some but not all patients. Taken together, our data suggest that CTC and platelet PD-L1 expression could play a role in predicting which patients should receive immune checkpoint inhibition and as a pharmacodynamics biomarker during treatment.
| S-EPMC8592410 | biostudies-literature
Project description:Early-phase trials targeting the T-cell inhibitory molecule programmed cell death ligand 1 (PD-L1) have shown clinical efficacy in cancer. This study was undertaken to determine whether PD-L1 is overexpressed in triple-negative breast cancer (TNBC) and to investigate the loss of PTEN as a mechanism of PD-L1 regulation. The Cancer Genome Atlas (TCGA) RNA sequencing data showed significantly greater expression of the PD-L1 gene in TNBC (n = 120) compared with non-TNBC (n = 716; P < 0.001). Breast tumor tissue microarrays were evaluated for PD-L1 expression, which was present in 19% (20 of 105) of TNBC specimens. PD-L1(+) tumors had greater CD8(+) T-cell infiltrate than PD-L1(-) tumors (688 cells/mm vs. 263 cells/mm; P < 0.0001). To determine the effect of PTEN loss on PD-L1 expression, stable cell lines were generated using PTEN short hairpin RNA (shRNA). PTEN knockdown led to significantly higher cell-surface PD-L1 expression and PD-L1 transcripts, suggesting transcriptional regulation. Moreover, phosphoinositide 3-kinase (PI3K) pathway inhibition using the AKT inhibitor MK-2206 or rapamycin resulted in decreased PD-L1 expression, further linking PTEN and PI3K signaling to PD-L1 regulation. Coculture experiments were performed to determine the functional effect of altered PD-L1 expression. Increased PD-L1 cell surface expression by tumor cells induced by PTEN loss led to decreased T-cell proliferation and increased apoptosis. PD-L1 is expressed in 20% of TNBCs, suggesting PD-L1 as a therapeutic target in TNBCs. Because PTEN loss is one mechanism regulating PD-L1 expression, agents targeting the PI3K pathway may increase the antitumor adaptive immune responses.
| S-EPMC4000553 | biostudies-literature
Project description:BackgroundProgrammed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) blockade immunotherapies have changed the landscape of cancer therapy. However, the main limitation of these therapies is the lack of definitively predictive biomarkers to predict treatment response. Whether PD-L1 expression on circulating tumor cells (CTCs) is associated with the clinical outcomes of immunotherapy remains to be extensively investigated.Materials and methodsOne hundred fifty-five patients with different advanced cancers were enrolled in this study and treated with anti-PD-1/PD-L1 monoclonal antibodies. Using the Pep@MNPs method, CTCs were isolated and enumerated. The PD-L1 expression levels were analyzed by an immunofluorescence assay for semiquantitative assessment with four categories (negative, low, medium, and high).ResultsPrior to immunotherapy, 81.93% (127/155) of patients had PD-L1-positive CTCs, and 71.61% (111/155) had at least one PD-L1-high CTC. The group with PD-L1-positive CTCs had a higher disease control rate (DCR) (71.56%, 91/127), with a DCR of only 39.29% (11/28) for the remaining individuals (p = .001). The objective response rate and DCR in PD-L1-high patients were higher than those in the other patients (32.44% vs. 13.64%, p = .018 and 75.68% vs. 40.91%, p < .0001, respectively). The reduction in the counts and ratios of PD-L1-positive CTCs and PD-L1-high CTCs reflected a beneficial response to PD-1/PD-L1 inhibitors. Furthermore, patients with PD-L1-high CTCs had significantly longer progression-free survival (4.9 vs. 2.2 months, p < .0001) and overall survival (16.1 vs. 9.0 months, p = .0235) than those without PD-L1-high CTCs.ConclusionThe PD-L1 level on CTCs may serve as a clinically actionable biomarker for immunotherapy, and its dynamic changes could predict the therapeutic response.Implications for practiceThis study was designed to investigate the role of programmed death-ligand 1 (PD-L1) expression on circulating tumor cells in predicting and monitoring response to programmed death-1 (PD-1)/PD-L1 blockade immunotherapies in patients with advanced cancer. The results of the study showed that PD-L1-high-expression circulating tumor cells (CTCs) were both a predictive biomarker and a prognostic factor in patients with advanced cancer treated with anti-PD-1/PD-L1 monoclonal antibodies. These observations suggest that PD-L1 level on CTCs is a potential clinical biomarker for immunotherapy.
| S-EPMC8649012 | biostudies-literature
Project description:Metastatic non-small cell lung cancer (NSCLC) is a highly fatal and immunogenic malignancy. Although the immune system is known to recognize these tumor cells, one mechanism by which NSCLC can evade the immune system is via overexpression of programmed cell death ligand 1 (PD-L1). Recent clinical trials of PD-1 and PD-L1 inhibitors have returned promising clinical responses. Important for personalizing therapy, patients with higher intensity staining for PD-L1 on tumor biopsies responded better. Thus, there has been interest in using PD-L1 tumor expression as a criterion for patient selection. Currently available methods of screening involve invasive tumor biopsy, followed by histological grading of PD-L1 levels. Biopsies have a high risk of complications, and only allow sampling from limited tumor sections, which may not reflect overall tumor heterogeneity. Circulating tumor cell (CTC) PD-L1 levels could aid in screening patients, and could supplement tissue PD-L1 biopsy results by testing PD-L1 expression from disseminated tumor sites. Towards establishing CTCs as a screening tool, we developed a protocol to isolate CTCs at high purity and immunostain for PD-L1. Monitoring of PD-L1 expression on CTCs could be an additional biomarker for precision medicine that may help in determining response to immunotherapies.
| S-EPMC5803213 | biostudies-literature
Project description:ObjectiveThe interaction between programmed cell death protein 1 (PD-1) on activated T-lymphocytes and programmed death-ligand 1 (PD-L1) on tumor cells or antigen-presenting cells sends immunosuppressive signals leading to the escape of tumor cells from the host anti-tumor immune response. Inhibiting this interaction with antibodies against PD-1 or PD-L1 is emerging as a valuable therapeutic strategy. However, tissue distribution patterns for PD-L1 and PD-1 in breast cancer patients from India are not reported, yet many clinical trials are underway. In this study the expression of PD-1 and PD-L1 in breast cancer patient samples from India was characterized.Materials and methodsThe study included 392 cases of operated breast cancer (2012-2017) from a tertiary cancer care center in Bangalore, Karnataka, India. Paraffin blocks were retrievable and receptor status was known. Immunohistochemistry (IHC) was performed using anti-PD-L1 and anti-PD-1 antibodies. RNA was isolated from 76 fresh tumors and nine adjacent normal tissues (2019). PD-L1 transcript levels were measured by RT-qPCR using Hypoxanthine-guanine phosphoribosyl transferase (HPRT) as a reference gene.ResultsBased on IHC, PD-1 expression within tumor-infiltrating immune cells (TIICs) was observed in 55/385 cases (14%) across all breast cancer types. In triple-negative breast cancer (TNBC), 21/132 cases (16%) showed PD-1 staining in TIICs. The overall expression of PD-L1 in breast tumor cells across all breast cancer subtypes and TIICs was 11% (41/378) and 39% (151/385), respectively. A relatively higher proportion of TNBC cases had PD-L1 expression in tumor cells (17/132 cases, 13%) and immune cells (68/132 cases, 52%). We also detected PD-L1 transcript expression by qRT-PCR in freshly isolated tumor samples.ConclusionThese findings show that around 52% (68/132) of the TNBC cases express PD-L1 in TIICs. Hence, anti-PD-1/PD-L1 therapy alone or combined with chemotherapy may be a promising treatment for TNBC in Indian patients.
| S-EPMC8734527 | biostudies-literature
Project description:BackgroundTumor cells express programmed death ligand 1 (PD-L1) and is a key immune evasion mechanism. PD-L1 expression in multiple breast cancer cell lines was evaluated to identify intrinsic differences that affect their potential for immune evasion.MethodsPD-L1 expression was analyzed in six breast cancer cell lines: AU565&MCF7 (luminal), BT20&HCC1143 (basal A), MDA231&HCC38 (basal B). Surface and intracellular PD-L1 expression +/- interferon γ for 48 hours was measured by flow cytometry. PD-L1 gene expression data for all breast cancer cell lines in the Comprehensive Cell Line Encyclopedia (CCLE) was analyzed. Correlation between PD-L1 levels and clinicopathologic parameters was analyzed within Oncomine datasets. A tissue microarray containing 61 invasive breast cancer primary tumor cores was stained for PD-L1 expression and analyzed.ResultsBasal breast cancer cells constitutively express the highest levels of PD-L1. All cell lines increased PD-L1 expression with interferon γ, but basal B cells (MDA-231 and HCC38) demonstrated the largest increases. There were no differences in protein localization between cell lines. In the CCLE data, basal cell lines demonstrated higher mean PD-L1 expression compared to luminal cell lines. High PD-L1 expressing basal cell lines over-express genes involved in invasion, proliferation, and chemoresistance compared to low PD-L1 basal cell lines. High PD-L1 basal cell lines had lower expression of IRF2BP2 and higher STAT1 levels compared to low PD-L1 expressing cell lines. Within Oncomine datasets PDL1 mRNA levels were higher in basal type tumors. The TMA analysis demonstrated that lymph node positive cases had higher levels of PD-L1 protein expression compared to lymph node negative cases.ConclusionsBasal type breast cancer (especially basal B) express greater levels of PD-L1 constitutively and with IFN γ. High PD-L1 basal cells over-express genes involved in invasion, motility, and chemoresistance. Targeting PD-L1 may enhance eradication of aggressive breast cancer cells by the immune system.
| S-EPMC3925108 | biostudies-literature
Project description:Circulating tumor cells (CTCs) hold great potential to answer key questions of how non-small cell lung cancer (NSCLC) evolves and develops resistance upon anti-PD-1/PD-L1 treatment. Currently, their clinical utility in NSCLC is compromised by a low detection rate with the established, Food and Drug Administration (FDA)-approved, EpCAM-based CellSearch® System. We tested an epitope-independent method (ParsortixTM system) and utilized it to assess PD-L1 expression of CTCs from NSCLC patients. We prospectively collected 127 samples, 97 of which were analyzed with the epitope-independent system in comparison to the CellSearch system. CTCs were determined by immunocytochemistry as intact, nucleated, CD45-, pankeratins (K)+ cells. PD-L1 status of CTCs was evaluated from 89 samples. With the epitope-independent system, ≥1 CTC per blood sample was detected in 59 samples (61%) compared to 31 samples (32%) with the EpCAM-based system. Upon PD-L1 staining, 47% of patients harbored only PD-L1+CTCs, 47% had PD-L1+ and PD-L1-CTCs, and only 7% displayed exclusively PD-L1-CTCs. The percentage of PD-L1+CTCs did not correlate with the percentage of PD-L1+ in biopsies determined by immunohistochemistry (p = 0.179). Upon disease progression, all patients showed an increase in PD-L1+CTCs, while no change or a decrease in PD-L1+CTCs was observed in responding patients (n = 11; p = 0.001). Our data show a considerable heterogeneity in the PD-L1 status of CTCs from NSCLC patients. An increase of PD-L1+CTCs holds potential to predict resistance to PD-1/PD-L1 inhibitors.
| S-EPMC6627043 | biostudies-literature
Project description:Activation of PD-1/PD-L1 checkpoint is a critical step for the immune evasion of malignant tumors including breast cancer. However, the epigenetic mechanism underlying the aberrant expression of PD-L1 in breast cancer cells remains poorly understood. To investigate the role of TET2 in the regulation of PD-L1 gene expression, quantitative reverse transcription PCR (RT-qPCR), Western blotting, chromatin immunoprecipitation (ChIP) assay and MeDIP/hMeDIP-qPCR were performed on MCF7 and MDA-MB-231 human breast cancer cells. Here, we reported that TET2 depletion upregulated PD-L1 gene expression in MCF7 cells. Conversely, ectopic expression of TET2 inhibited PD-L1 gene expression in MDA-MB-231 cells. Mechanistically, TET2 protein recruits histone deacetylases (HDACs) to PD-L1 gene promoter and orchestrates a repressive chromatin structure to suppress PD-L1 gene transcription, which is likely independent of DNA demethylation. Consistently, treatment with HDAC inhibitors upregulated PD-L1 gene expression in wild-type (WT) but not TET2 KO MCF7 cells. Furthermore, analysis of the CCLE and TCGA data showed a negative correlation between TET2 and PD-L1 expression in breast cancer. Taken together, our results identify a new epigenetic regulatory mechanism of PD-L1 gene transcription, linking the catalytic activity-independent role of TET2 to the anti-tumor immunity in breast cancer.
| S-EPMC8125390 | biostudies-literature
Project description:Several ongoing clinical trials are investigating the use of immuno-targeting therapy with programmed cell death protein-1 and programmed death-ligand 1 (PD-L1) inhibitors for triple-negative breast cancer. However, the role of PD-L1 expression in HER2-positive breast cancer remains unclear. We investigated the clinicopathological utility of PD-L1 expression in HER2-positive breast cancer. Cohort A included 248 patients with invasive breast cancer (all subtypes). Cohort B included 126 HER2-positive patients who received neoadjuvant chemotherapy (NAC) concomitant with trastuzumab. The relationship of PD-L1 expression on the cancer cells with clinicopathological factors including pathological complete response (pCR) and prognosis was investigated. In cohort A, 8.1% patients were PD-L1-positive; PD-L1 positivity showed a correlation with high degree of tumor-infiltrating lymphocytes (TILs), estrogen receptor negativity, progesterone receptor negativity, and high histological grade. In cohort B, 17.5% patients were PD-L1-positive; PD-L1 positivity showed a significant correlation with high degree of TILs and high abundance of CD8-positive TILs. The pCR rates were related to TILs and PD-L1 expression. Among PD-L1-negative patients, high CD8-positive TILs were associated with significantly better prognosis. In conclusion, 17.5% of HER2-positive type patients were PD-L1-positive. PD-L1 expression was associated with response to NAC with trastuzumab in patients with HER2-positive breast cancer.
| S-EPMC6853939 | biostudies-literature
Project description:Although circulating tumor cells (CTCs) have shown promise as potential biomarkers for diagnostic and prognostic assessment in gastric cancer (GC), determining the predictive and prognostic value of programmed death-ligand 1 (PD-L1)-positive CTCs in patients with GC is a challenge. Here, we identified that the expression of total vimentin (VIM) protein was positively correlated with PD-L1 and inhibited CD8+ T-cell activation in patients with GC according to bioinformatics analysis. Notably, coexpression of PD-L1 and cell-surface VIM (CSV) was detected by immunofluorescence and immunohistochemistry assay in locally advanced GC tumor specimens and metastatic lymph nodes. Likewise, CSV expression level was significantly decreased after transiently knocking down PD-L1 in GC cell lines. Based on our established CTC detection platform, CTCs were isolated from peripheral blood samples collected from 70 patients (38 resectable and 32 unresectable) with GC using magnetic positive selection and a CSV-specific monoclonal antibody, 84-1. CSV+ PD-L1+ CTCs were observed in 50 of 70 (71%) GC patient samples, ranging from 0 to 261 mL-1 . A higher number of CSV+ PD-L1+ CTCs were significantly associated with a short survival duration and poor therapeutic response. This study demonstrated that detection of PD-L1+ CTCs using a CSV-enrichment method has promising value as a clinically relevant prognostic marker for GC.
| S-EPMC7138401 | biostudies-literature