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POL and Z1031 Gene Expression_Final

ABSTRACT: Background: Unlike estrogen receptor (ER) negative breast cancer, ER-positive breast cancer outcomes are less influenced by lymphocyte content, indicating a need for investigation of checkpoint targets and immune tolerance mechanisms that may be specific to this disease subset. Methods: A supervised analysis of microarray data from the Alliance/ACOSOG Z1031 trial was conducted to identify upregulated genes in Luminal B breast cancers that exhibited persistent tumor proliferation despite aromatase inhibitor therapy (33 cases Ki67 >10%) versus Luminal B breast cancers that were more sensitive (33 cases Ki67 <10%). Results: This study identified thirty genes (Pearson’s r>0.4 with Ki67 as a continuous variable). These genes were enriched for immune tolerance processes (p<0.005) and three targetable immune checkpoint components were upregulated in resistant cases: IDO1, LAG3, and PD1. High IDO1 mRNA associated with poor prognosis in ER+ disease across two independent cohorts (METABRIC and TCGA). Furthermore, analysis indicated IDO1 was tightly associated with IFN-γ/STAT1 signaling. As a composite immune tolerance signature, expression of these pathway components associated with higher baseline Ki67 and lower ER, PgR levels and poor disease specific survival. In tissue microarray analysis, IDO1 was observed in stromal cells and tumor-associated macrophages, with a higher incidence in Luminal B cases. Further mRNA and tissue microarray analyses associated IDO1 expression with the presence of macrophages (M1 by CIBERSORT) and regulatory T cells. Conclusion: Targetable immune-checkpoint components are upregulated in majority of neoadjuvant endocrine therapy resistant Luminal B cases. Our findings suggests potential for immune checkpoint inhibitors in poor outcome ER+ breast cancer.

ORGANISM(S): Homo sapiens

PROVIDER: GSE136644 | GEO | 2020/04/13

REPOSITORIES: GEO

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Project description:Tumor infiltrating lymphocytes (TILs) play a critical role in modulating the immunoediting features in certain malignancies like triple negative breast cancer (TNBC). Nevertheless, much is still unknown concerning the specific responses of tumors when challenged by lymphocyte infiltration. Based on this void, we conducted a immuno-phenotype comparison using mRNA sequencing between the TNBC cell line MDA-MB-231 and the luminal breast cancer cell line MCF7 after both were co-cultured with activated human T-cells. We found that, though the cytokine-induced immune signature of the two cell lines was similar, MDA-MD-231 cells were able to transcribe IDO1 at a significantly higher level than MCF7 cells. Though no differences occurred in upstream JAK/STAT1 signaling or IDO1 mRNA stability between the two cell lines, stimulation with IFNÎ³ was able to differentially induce IDO protein expression and enzymatic activity in ER- cell lines compared to ER+ cell lines. Further experiments show that 5-aza-deoxycytidine treatment was able to reverse suppression of IDO1 expression in MCF7 cells, suggesting DNA methylation as a potential determinant in IDO1 induction. By analyzing TCGA breast cancer datasets, we discovered subtype-specific mRNA and promoter methylation differences in IDO1, with TNBC/basal subtypes exhibiting lower methylation/higher expression and ER+/luminal subtypes exhibiting higher methylation/lower expression. We confirmed this trend of IDO1 methylation by bisulfite pyrosequencing breast cancer cell lines and an independent cohort of primary breast tumors. Taken together, these findings suggest that IDO1 methylation regulates anti-immune responses in breast cancer subtypes and could be used as a predictive biomarker for IDO inhibitor-based immunotherapy. To determine the immunomodulatory effects of cytokines secreted by activated human T-cells on breast cancer cells, we performed RNAseq analysis in MCF7 and MDA-MB-231 cells, after co-culturing them with normal PBMCs activated with anti-CD3/CD28 antibodies in a contact-independent manner. MDA-MB-231 or MCF7 cells were co-cultured with PBMCs alone or the conditioned-media or a combination of both for 24 hrs, and then total RNA was harvest for RNA-seq analysis.

Project description:Breast cancer is a heterogeneous disease comprised of at least five major subtypes. Luminal subtype tumors confer a more favourable patient prognosis, which is in part, attributed to the Estrogen Receptor-alpha (ER) positivity and anti-hormone responsiveness of these tumors. Expression of the forkhead box transcription factor, FOXA1, also correlates with the luminal subtype and patient survival, but is present in a subset of ER-negative tumors. Similarly, FOXA1 is consistently expressed in luminal breast cancer cell lines even in the absence of ER. In contrast, basal breast cancer cell lines do not express FOXA1, and loss of FOXA1 in luminal cells increases migration and invasion, characteristics of the basal subtype. To delineate an ER-independent role for FOXA1 in maintaining the luminal phenotype, and hence a more favourable prognosis, we performed cDNA microarray analyses on luminal FOXA1-positive, ER-positive (MCF7, T47D) and FOXA1-positive, ER-negative (MDA-MB-453, SKBR3) cell lines in the presence or absence of transient FOXA1 silencing. This resulted in three FOXA1 transcriptomes: (1) a luminal-signature (consistent across cell lines), (2) an ER-positive signature (restricted to MCF7 and T47D) and (3) an ER-negative signature (restricted to MDA-MB-453 and SKBR3). Use of Gene Set Enrichment Analyses (GSEA) as a phenotyping tool revealed that FOXA1 silencing resulted in a transcriptome shift from luminal to basal gene expression signatures. FOXA1 binds to both luminal and basal genes within luminal breast cancer cells, suggesting that it not only transactivates luminal genes, but also represses basal-associated genes. From these results we conclude that FOXA1 controls plasticity between basal and luminal cells, playing a dominant role in repressing the basal phenotype, and thus tumor aggressiveness, in luminal breast cancer cells. Although it has been proposed that FOXA1-targeting agents may be useful for treating luminal tumors, these data suggest that this approach may promote transitions toward a more aggressive cancer. FOXA1 siRNA treated breast cell lines compared directly to nonspecific siRNA treated cell lines using Agilent 4X44 microarrays.

Project description:Breast cancer is a heterogeneous disease comprised of at least five major subtypes. Luminal subtype tumors confer a more favorable patient prognosis, which is in part, attributed to the Estrogen Receptor-α (ER) positivity and anti-hormone responsiveness of these tumors. Expression of the forkhead box transcription factor, FOXA1, also correlates with the luminal subtype and patient survival, but is present in a subset of ER-negative tumors. Similarly, FOXA1 is consistently expressed in luminal breast cancer cell lines even in the absence of ER. In contrast, basal breast cancer cell lines do not express FOXA1, and loss of FOXA1 in luminal cells increases migration and invasion, characteristics of the basal subtype. To delineate an ER-independent role for FOXA1 in maintaining the luminal phenotype, and hence a more favorable prognosis, we performed cDNA microarray analyses on luminal FOXA1-positive, ER-positive (MCF7, T47D) and FOXA1-positive, ER-negative (MDA-MB-453, SKBR3) cell lines in the presence or absence of transient FOXA1 silencing. This resulted in three FOXA1 transcriptomes: (1) a luminal-signature (consistent across cell lines), (2) an ER-positive signature (restricted to MCF7 and T47D) and (3) an ER-negative signature (restricted to MDA-MB-453 and SKBR3). Use of Gene Set Enrichment Analyses (GSEA) as a phenotyping tool revealed that FOXA1 silencing resulted in a transcriptome shift from luminal to basal gene expression signatures. FOXA1 binds to both luminal and basal genes within luminal breast cancer cells, suggesting that it not only transactivates luminal genes, but also represses basal-associated genes. From these results we conclude that FOXA1 controls plasticity between basal and luminal cells, playing a dominant role in repressing the basal phenotype, and thus tumor aggressiveness, in luminal breast cancer cells. Although it has been proposed that FOXA1-targeting agents may be useful for treating luminal tumors, these data suggest that this approach may promote transitions toward a more aggressive cancer.

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POL and Z1031 Gene Expression_Final

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