Syndecan-1 is a novel molecular marker for triple negative inflammatory breast cancer and modulates the cancer stem cell phenotype via the IL-6/STAT3, Notch and EGFR signaling pathways

Background

Inflammatory breast cancer (IBC), a particularly aggressive form of breast cancer, is characterized by cancer stem cell (CSC) phenotype. Due to a lack of targeted therapies, the identification of molecular markers of IBC is of major importance. The heparan sulfate proteoglycan Syndecan-1 acts as a coreceptor for growth factors and chemokines, modulating inflammation, tumor progression, and cancer stemness, thus it may emerge as a molecular marker for IBC.

Methods

We characterized expression of Syndecan-1 and the CSC marker CD44, Notch-1 & -3 and EGFR in carcinoma tissues of triple negative IBC (n = 13) and non-IBC (n = 17) patients using qPCR and immunohistochemistry. Impact of siRNA-mediated Syndecan-1 knockdown on the CSC phenotype of the human triple negative IBC cell line SUM-149 and HER-2-overexpressing non-IBC SKBR3 cells employing qPCR, flow cytometry, Western blotting, secretome profiling and Notch pharmacological inhibition experiments. Data were statistically analyzed using Student’s t-test/Mann-Whitney U-test or one-way ANOVA followed by Tukey’s multiple comparison tests.

Results

Our data indicate upregulation and a significant positive correlation of Syndecan-1 with CD44 protein, and Notch-1 & -3 and EGFR mRNA in IBC vs non-IBC. ALDH1 activity and the CD44⁽⁺⁾CD24^(-/low) subset as readout of a CSC phenotype were reduced upon Syndecan-1 knockdown. Functionally, Syndecan-1 silencing significantly reduced 3D spheroid and colony formation. Intriguingly, qPCR results indicate downregulation of the IL-6, IL-8, CCL20, gp130 and EGFR mRNA upon Syndecan-1 suppression in both cell lines. Moreover, Syndecan-1 silencing significantly downregulated Notch-1, -3, -4 and Hey-1 in SUM-149 cells, and downregulated only Notch-3 and Gli-1 mRNA in SKBR3 cells. Secretome profiling unveiled reduced IL-6, IL-8, GRO-alpha and GRO a/b/g cytokines in conditioned media of Syndecan-1 knockdown SUM-149 cells compared to controls. The constitutively activated STAT3 and NFκB, and expression of gp130, Notch-1 & -2, and EGFR proteins were suppressed upon Syndecan-1 ablation. Mechanistically, gamma-secretase inhibition experiments suggested that Syndecan-1 may regulate the expression of IL-6, IL-8, gp130, Hey-1, EGFR and p-Akt via Notch signaling.

Conclusions

Syndecan-1 acts as a novel tissue biomarker and a modulator of CSC phenotype of triple negative IBC via the IL-6/STAT3, Notch and EGFR signaling pathways, thus emerging as a promising therapeutic target for IBC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0621-z) contains supplementary material, which is available to authorized users.

Validation of CyTOF Against Flow Cytometry for Immunological Studies and Monitoring of Human Cancer Clinical Trials

Flow cytometry is a widely applied approach for exploratory immune profiling and biomarker discovery in cancer and other diseases. However, flow cytometry is limited by the number of parameters that can be simultaneously analyzed, severely restricting its utility. Recently, the advent of mass cytometry (CyTOF) has enabled high dimensional and unbiased examination of the immune system, allowing simultaneous interrogation of a large number of parameters. This is important for deep interrogation of immune responses and particularly when sample sizes are limited (such as in tumors). Our goal was to compare the accuracy and reproducibility of CyTOF against flow cytometry as a reliable analytic tool for human PBMC and tumor tissues for cancer clinical trials. We developed a 40+ parameter CyTOF panel and demonstrate that compared to flow cytometry, CyTOF yields analogous quantification of cell lineages in conjunction with markers of cell differentiation, function, activation, and exhaustion for use with fresh and viably frozen PBMC or tumor tissues. Further, we provide a protocol that enables reliable quantification by CyTOF down to low numbers of input human cells, an approach that is particularly important when cell numbers are limiting. Thus, we validate CyTOF as an accurate approach to perform high dimensional analysis in human tumor tissue and to utilize low cell numbers for subsequent immunologic studies and cancer clinical trials.

Inflammatory breast cancer: Activation of the aryl hydrocarbon receptor and its target CYP1B1 correlates closely with Wnt5a/b-β-catenin signalling, the stem cell phenotype and disease progression

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AHR is over-expressed and hyperactivated in carcinoma tissues of IBC patients.

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AHR knockdown inhibits expression of CYP1B1 and Wnt5a in IBC cells.

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AHR and CYP1B1 expression correlates with Wnt5 a/b and b-catenin expression levels.

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AHR and CYP1B1 expression correlates with percentage of CD44⁽⁺⁾/CD24^(−/low) subset in IBC.

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AHR and its surrogate molecules correlate with IBC poor prognosis.

The aim of the present study was to evaluate the expression levels of the aryl hydrocarbon receptor (AHR) and its target gene CYP1B1 and to correlate their expression with Wnt5a/b-β-catenin, the CD44⁺/CD24^(−/low) cancer stem cell (CSC) subset and factors associated with poor prognosis in inflammatory breast cancer (IBC) and non-IBC patients. The methods of analysis used were quantitative real-time PCR, western blotting, immunohistochemistry and flow cytometry. Compared to non-IBC tissues, IBC tissues exhibited the overexpression of AHR and its target gene/protein CYP1B1. AHR and CYP1B1 mRNA levels were associated with the poor clinical prognosis markers tumour grade, lymphovascular invasion, cell proliferation and lymph node metastasis. Furthermore, AHR expression correlated with the expression of Wnt5a/b and β-catenin signalling molecules, and Wnt5a mRNA expression was downregulated in the SUM149 human IBC cell line and the MDA-MB-231 non-IBC cell line upon inhibition of AHR. AHR gene knockout (CRISPR-Cas9) inhibits CYP1B1 and Wnt5a expression in the IBC cell line. The CD44⁺/CD24^(−/low) subset was significantly correlated with the expression of AHR, CYP1B1, Wnt5a/b and β-catenin in IBC tissues. The overexpression of AHR and its target CYP1B1 correlated with the expression of Wnt5a/b and β-catenin, CSCs, and poor clinical prognostic factors of IBC. Thus, targeting AHR and/or its downstream target molecules CYP1B1 and Wnt5a/b may represent a therapeutic approach for IBC.

The transcription factor IRF2 drives interferon-mediated CD8+ T cell exhaustion to restrict anti-tumor immunity

Type I and II interferons (IFNs) stimulate pro-inflammatory programs that are critical for immune activation, but also induce immune-suppressive feedback circuits that impede control of cancer growth. Here, we sought to determine how these opposing programs are differentially induced. We demonstrated that the transcription factor interferon regulatory factor 2 (IRF2) was expressed by many immune cells in the tumor in response to sustained IFN signaling. CD8+ T cell-specific deletion of IRF2 prevented acquisition of the T cell exhaustion program within the tumor and instead enabled sustained effector functions that promoted long-term tumor control and increased responsiveness to immune checkpoint and adoptive cell therapies. The long-term tumor control by IRF2-deficient CD8+ T cells required continuous integration of both IFN-I and IFN-II signals. Thus, IRF2 is a foundational feedback molecule that redirects IFN signals to suppress T cell responses and represents a potential target to enhance cancer control.

An interim report on the investigator-initiated phase 2 study of pembrolizumab immunological response evaluation (INSPIRE)

BACKGROUND

Immune checkpoint inhibitors (ICIs) demonstrate unprecedented efficacy in multiple malignancies; however, the mechanisms of sensitivity and resistance are poorly understood and predictive biomarkers are scarce. INSPIRE is a phase 2 basket study to evaluate the genomic and immune landscapes of peripheral blood and tumors following pembrolizumab treatment.

METHODS

Patients with incurable, locally advanced or metastatic solid tumors that have progressed on standard therapy, or for whom no standard therapy exists or standard therapy was not deemed appropriate, received 200 mg pembrolizumab intravenously every three weeks. Blood and tissue samples were collected at baseline, during treatment, and at progression. One core biopsy was used for immunohistochemistry and the remaining cores were pooled and divided for genomic and immune analyses. Univariable analysis of clinical, genomic, and immunophenotyping parameters was conducted to evaluate associations with treatment response in this exploratory analysis.

RESULTS

Eighty patients were enrolled from March 21, 2016 to June 1, 2017, and 129 tumor and 382 blood samples were collected. Immune biomarkers were significantly different between the blood and tissue. T cell PD-1 was blocked (≥98%) in the blood of all patients by the third week of treatment. In the tumor, 5/11 (45%) and 11/14 (79%) patients had T cell surface PD-1 occupance at weeks six and nine, respectively. The proportion of genome copy number alterations and abundance of intratumoral 4-1BB+ PD-1+ CD8 T cells at baseline (P < 0.05), and fold-expansion of intratumoral CD8 T cells from baseline to cycle 2-3 (P < 0.05) were associated with treatment response.

CONCLUSION

This study provides technical feasibility data for correlative studies. Tissue biopsies provide distinct data from the blood and may predict response to pembrolizumab.

Pre-encoded responsiveness to type I interferon in the peripheral immune system defines outcome of PD1 blockade therapy

Type I interferons (IFN-Is) are central regulators of anti-tumor immunity and responses to immunotherapy, but they also drive the feedback inhibition underlying therapeutic resistance. In the present study, we developed a mass cytometry approach to quantify IFN-I-stimulated protein expression across immune cells and used multi-omics to uncover pre-therapy cellular states encoding responsiveness to inflammation. Analyzing peripheral blood cells from multiple cancer types revealed that differential responsiveness to IFN-Is before anti-programmed cell death protein 1 (PD1) treatment was highly predictive of long-term survival after therapy. Unexpectedly, IFN-I hyporesponsiveness efficiently predicted long-term survival, whereas high responsiveness to IFN-I was strongly associated with treatment failure and diminished survival time. Peripheral IFN-I responsive states were not associated with tumor inflammation, identifying a disconnect between systemic immune potential and 'cold' or 'hot' tumor states. Mechanistically, IFN-I responsiveness was epigenetically imprinted before therapy, poising cells for differential inflammatory responses and dysfunctional T cell effector programs. Thus, we identify physiological cell states with clinical importance that can predict success and long-term survival of PD1-blocking immunotherapy.

Translational randomized phase II trial of cabozantinib in combination with nivolumab in advanced, recurrent, or metastatic endometrial cancer

BACKGROUND

Combining immunotherapy and antiangiogenic agents is a promising treatment strategy in endometrial cancer. To date, no biomarkers for response have been identified and data on post-immunotherapy progression are lacking. We explored the combination of a checkpoint inhibitor (nivolumab) and an antiangiogenic agent (cabozantinib) in immunotherapy-naïve endometrial cancer and in patients whose disease progressed on previous immunotherapy with baseline biopsy for immune profiling.

PATIENTS AND METHODS

In this phase II trial (ClinicalTrials.gov NCT03367741, registered December 11, 2017), women with recurrent endometrial cancer were randomized 2:1 to nivolumab with cabozantinib (Arm A) or nivolumab alone (Arm B). The primary endpoint was Response Evaluation Criteria in Solid Tumors-defined progression-free survival (PFS). Patients with carcinosarcoma or prior immune checkpoint inhibitor received combination treatment (Arm C). Baseline biopsy and serial peripheral blood mononuclear cell (PBMC) samples were analyzed and associations between patient outcome and immune data from cytometry by time of flight (CyTOF) and PBMCs were explored.

RESULTS

Median PFS was 5.3 (90% CI 3.5 to 9.2) months in Arm A (n=36) and 1.9 (90% CI 1.6 to 3.4) months in Arm B (n=18) (HR=0.59, 90% CI 0.35 to 0.98; log-rank p=0.09, meeting the prespecified statistical significance criteria). The most common treatment-related adverse events in Arm A were diarrhea (50%) and elevated liver enzymes (aspartate aminotransferase 47%, alanine aminotransferase 42%). In-depth baseline CyTOF analysis across treatment arms (n=40) identified 35 immune-cell subsets. Among immunotherapy-pretreated patients in Arm C, non-progressors had significantly higher proportions of activated tissue-resident (CD103+CD69+) ɣδ T cells than progressors (adjusted p=0.009).

CONCLUSIONS

Adding cabozantinib to nivolumab significantly improved outcomes in heavily pretreated endometrial cancer. A subgroup of immunotherapy-pretreated patients identified by baseline immune profile and potentially benefiting from combination with antiangiogenics requires further investigation.

Tumor microenvironmental plasmacytoid dendritic cells contribute to breast cancer lymph node metastasis via CXCR4/SDF-1 axis

PURPOSE

Plasmacytoid dendritic cells (PDCs) infiltration into breast cancer tissues is associated with poor prognosis. Also, CXCR4 shows compelling evidences to be exploited by cancer cells to migrate to distant sites. The present study investigated lymph node metastasis in the light of PDCs infiltration and the potential cross talk with CXCR4/SDF-1 chemokine axis.

METHODS

We assessed circulating PDCs proportions drained from the axillary tributaries, and the in situ expression of both CD303 and CXCR4 in breast cancer patients with positive lymph nodes (pLN) and negative lymph nodes (nLN) using immunohistochemistry and flow cytometry. We also analyzed the expression of SDF-1 in lymph nodes of pLN and nLN patients. We studied the effect of the secretome of PDCs of pLN and nLN patients on the expression of CXCR4 and activation of NF-κB in human breast cancer cell lines SKBR3 and MCF-7. TNF-α mRNA expression level in PDCs from both groups was determined by qPCR.

RESULTS

Our findings indicate increased infiltration of PDCs in breast cancer tissues of pLN patients than nLN patients, which correlates with CXCR4⁺ cells percentage. Interestingly, SDF-1 is highly immunostained in lymph nodes of pLN patients compared to nLN patients. Our in vitro experiments demonstrate an upregulation of NF-κB expression and CXCR4 cells upon stimulation with PDCs secretome of pLN patients than those of nLN patients. Also, PDCs isolated from pLN patients exhibited a higher TNF-α mRNA expression than nLN patients. Treatment of MCF-7 cell lines with TNF-α significantly upregulates CXCR4 expression.

CONCLUSIONS

Our findings suggest a potential role for microenvironmental PDCs in breast cancer lymph node metastasis via CXCR4/SDF-1 axis.

The immunomodulatory role of tumor Syndecan-1 (CD138) on ex vivo tumor microenvironmental CD4+ T cell polarization in inflammatory and non-inflammatory breast cancer patients

Herein, we aimed to identify the immunomodulatory role of tumor Syndecan-1 (CD138) in the polarization of CD4⁺ T helper (Th) subsets isolated from the tumor microenvironment of inflammatory breast cancer (IBC) and non-IBC patients. Lymphocytes and mononuclear cells isolated from the axillary tributaries of non-IBC and IBC patients during modified radical mastectomy were either stimulated with the secretome as indirect co-culture or directly co-cultured with control and Syndecan-1-silenced SUM-149 IBC cells. In addition, peripheral blood mononuclear cells (PBMCs) of normal subjects were used for the direct co-culture. Employing flow cytometry, we analyzed the expression of the intracellular IFN-γ, IL-4, IL-17, and Foxp3 markers as readout for basal and co-cultured Th₁, Th₂, Th₁₇, and T_reg CD4⁺ subsets, respectively. Our data revealed that IBC displayed a lower basal frequency of Th₁ and Th₂ subsets than non-IBC. Syndecan-1-silenced SUM-149 cells significantly upregulated only T_reg subset polarization of normal subjects relative to controls. However, Syndecan-1 silencing significantly enhanced the polarization of Th₁₇ and T_reg subsets of non-IBC under both direct and indirect conditions and induced only Th₁ subset polarization under indirect conditions compared to control. Interestingly, qPCR revealed that there was a negative correlation between Syndecan-1 and each of IL-4, IL-17, and Foxp3 mRNA expression in carcinoma tissues of IBC and that the correlation was reversed in non-IBC. Mechanistically, Syndecan-1 knockdown in SUM-149 cells promoted Th₁₇ cell expansion via upregulation of IL-23 and the Notch ligand DLL4. Overall, this study indicates a low frequency of the circulating antitumor Th₁ subset in IBC and suggests that tumor Syndecan-1 silencing enhances ex vivo polarization of CD4⁺ Th₁₇ and T_reg cells of non-IBC, whereby Th₁₇ polarization is possibly mediated via upregulation of IL-23 and DLL4. These findings suggest the immunoregulatory role of tumor Syndecan-1 expression in Th cell polarization that may have therapeutic implications for breast cancer.

Abstract 3302: High incidence of MAC387 positive cells in the carcinoma tissues of inflammatory breast cancer patients correlate with the detection of multiple human Cytomegalovirus genotypes and invasive properties of the disease

Introduction: Previously we showed that the incidence of multiple human cytomegalovirus (HCMV) genotypes in the carcinoma tissues of inflammatory breast cancer (IBC) patients plays essential role in the disease progression. Primary HCMV infection to monocytes induces differentiation and biological turnover of monocytes to macrophages. In addition infected macrophages serves as “mobile vectors” for virus spreading and dissemination to different organs mainly by transendothelial migration. In addition we screened for the infiltration of CD14+ and CD68+ monocytes/macrophages markers in the carcinoma tissues of IBC versus non-IBC patients we showed that of CD14+ cells highly infiltrate tumor microenvironment (TME) of IBC patients compared to non-IBC.

Aims: In the present study we aim to 1) Assess the level of expression of MAC387 protein by monocytes/macrophages infiltrating TME of IBC versus non-IBC patients; 2) Test the correlation between the density of infiltrated MAC387+ cells and the incidence of different HCMV genotypes in carcinoma tissues of IBC versus non-IBC tissues. Since MAC387 found to be more common in cancers characterized by high metastatic properties we will also 3) determine whether the expression of MCA387 correlate with lymph-node metastasis and lymphovascular invasion in IBC versus non-IBC breast cancer patients.

Materials and Methods: A total of 135 breast cancer patients (91 non-IBC and 44 IBC) were enrolled to the present study during the period of January 2012 to September 2015 from Ain Shams university Hospitals. Detection of MAC387 marker was assessed by immunohistochemistry and HCMV genotypes were detected using multiplex PCR methodology.

Results: MAC387+ positive cells were more prevalent in IBC tissues than non-IBC tissues (p = 0.4). Incidence of higher number of MAC387+ cells were positively correlate with higher number of metastatic lymph nodes in both IBC and non-IBC patients r = 0.807 and 0.779 respectively. Moreover, Incidence of higher number of MAC387+ cells found to be positively correlate with lymphovascular invasion in IBC patients r = 0622. Detection of multiple HCMV genotypes was statistically higher (p = 0.04) in IBC tissues in comparison with non-IBC tissues. Moreover, triple negative non-IBC and IBC tissues showed higher incidence of multiple HCMV genotypes in comparison with hormonal positive non-IBC and IBC tissues. of the monocytes/macrophages MAC387+ positive cells were more prevalent in IBC tissues showed multiple HCMV genotypes in comparison with IBC tissues showed single HCMV genotype (p = 0.46).

Conclusion: MAC387+ positive cells were more prevalent in IBC tissues and correlate with presence of multiple HCMV genotypes and high invasive properties of the disease.

Citation Format: Hossam Taha Mohamed, Ramy Gadalla, Sherif Abdel Aziz Ibrahim, M. Akram Nouh, Mohamed El-Shinawi, Robert J. Schneider, Mona Mostafa Mohamed. High incidence of MAC387 positive cells in the carcinoma tissues of inflammatory breast cancer patients correlate with the detection of multiple human Cytomegalovirus genotypes and invasive properties of the disease. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3302.

Peripheral CD4 T cell resistance to type I interferon defines outcome of PD1 blockade therapy in human cancer

Type I interferons (IFN-Is) are paradoxically associated with both the success and failure of immune checkpoint blockade (ICB), with increased inflammation in the tumor associated with better response. To understand how IFN-Is modulate the immune response to ICB, we developed a mass cytometry approach to quantify pro- and anti-inflammatory features of IFN-I responsiveness at the single cell level. Using high dimensional analysis we show that the inflammatory responses that are beneficial in the peripheral blood are the opposite of what is considered beneficial in the tumor, thus identifying a functional disconnect between the peripheral and tumor immune compartments. We demonstrate that an initial resistance to IFN-I by CD4 T effector (Teff) cells in the peripheral blood is strongly associated to long-term benefit of anti-PD1 therapy in patients with melanoma, head and neck and lung cancers. By contrast, a strong IFN-I response correlates with progression and low survival probability. Upregulation of PDL1 by IFN-I did not relate to response, however patients with myeloid cells that initially reacted to IFN-I with higher IDO1 induction survived longer after anti-PD1. Single-cell RNA-sequencing stratified based on response to IFN-I identified transcriptional programs associated with therapy response, providing mechanistic insight into the peripheral cell states prior to therapy conducive to anti-PD1 success. Thus, contrary to a benefit of an initially inflamed tumor environment, an initially restrained CD4 Teff inflammatory response to IFN-I averts therapy failure and enables tumor control. This IFN-I response potential is a promising new biomarker for prediction of which patients will benefit most from anti-PD1 therapy.

Supported by Canadian Institutes of Health Research (CIHR) Foundation Grant FDN148386, the Canadian Cancer Society (CCSRI) Innovation Award No. 706230, the National Institutes of Health (NIH) grant AI085043, The Terry Fox New Frontiers Grant the Scotiabank Research Chair to D.G.B, the Princess Margaret Hold’em for Life Cancer Research Fellowship (G. M. B).

Tumor reactive γδ T cells contribute to a complete response to PD-1 blockade in a Merkel cell carcinoma patient

Immunotherapies targeting PD-1/PD-L1 are now widely used in the clinic to treat a variety of malignancies. While most of the research on T cell exhaustion and PD-1 blockade has been focused on conventional αβ T cells, the contribution of innate-like T cells such as γδ T cells to anti-PD-1/PD-L1 mediated therapy is limited. Here we show that tumor reactive γδ T cells respond to PD-1 blockade in a Merkel cell carcinoma (MCC) patient experiencing a complete response to therapy. We find clonally expanded γδ T cells in the blood and tumor after pembrolizumab treatment, and this Vγ2Vδ1 clonotype recognizes Merkel cancer cells in a TCR-dependent manner. Notably, the intra-tumoral γδ T cells in the MCC patient are characterized by higher expression of PD-1 and TIGIT, relative to conventional CD4 and CD8 T cells. Our results demonstrate that innate-like T cells could also contribute to an anti-tumor response after PD-1 blockade.

Mass cytometry immunostaining protocol for multiplexing clinical samples

This is a cytometry by time-of-flight (CyTOF) staining protocol for hematopoietic-derived cells, that leverages live-cell barcoding using receptor-type tyrosine-protein phosphatase C (CD45) antibodies conjugated to metal isotopes in combination with DNA-based palladium barcoding to multiplex up to 40 samples. In this protocol, DNA-based barcoding is performed before surface and intracellular immunostaining, which reduces the batch effects that result from day-to-day variations in staining and instrument sensitivity. This protocol also reduces antibody consumption and eliminates the need for repeated instrument adjustment.

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Mass cytometry immunostaining for 40+ samples to reduce batch-to-batch variation

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Barcoding samples before immunostaining ensures consistency across all samples

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Reduction in antibody volume consumption and data acquisition time

Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.