gsk-2816126 and Lung-Neoplasms

Highly invasive and rapidly fatal, small-cell lung cancer (SCLC) has been an insurmountable gulf since discovery. Innate immunity plays a vital role in anti-tumor response, among which macrophages contribute to an indispensable character. Here, we found that macrophage infiltration in SCLC reduced significantly in a stage-dependent manner, attributed to the decreased expression of CCL2, a potent chemoattractant for monocytes. Validated by ChIP-qPCR and MassArray methylation analysis, CCL2 expression was inhibited by EZH2-mediated H3K27me3 in the enhancer regions and DNMT1-mediated DNA methylation in the promoter regions, the process of which could be reversed by small-molecular compounds, EPZ011989 and Decitabine. Direct cell-cell contact between SCLC cells and macrophages skewed the phenotype of macrophages to be more M1-like. Furthermore, in an ectopic engraft model of SCLC, disruption of EZH2/DNMT1 function using the combination treatment of EPZ011989 and Decitabine potently abrogated the inhibition of macrophage infiltration and thus suppressed tumor growth, the effect of which was impaired by CCL2 neutralization or macrophage depletion. Overall, this work provides new insights into the role of macrophages in SCLC and establishes a rationale for constructing novel therapeutic avenues for SCLC patients.

Topics: Adolescent; Adult; Aged; Animals; Antineoplastic Combined Chemotherapy Protocols; Carcinogenesis; Chemokine CCL2; CpG Islands; Decitabine; DNA (Cytosine-5-)-Methyltransferase 1; DNA Methylation; Enhancer Elements, Genetic; Enhancer of Zeste Homolog 2 Protein; Epigenesis, Genetic; Female; Histones; Humans; Indoles; Lung; Lung Neoplasms; Male; Mice; Middle Aged; Phagocytosis; Pyridones; Small Cell Lung Carcinoma; Tissue Array Analysis; Tumor-Associated Macrophages; Xenograft Model Antitumor Assays; Young Adult

Emerging evidence has illustrated the importance of epigenomic reprogramming in cancer, with altered post-translational modifications of histones contributing to pathogenesis. However, the contributions of histone modifiers to breast cancer progression are unclear, and how these processes vary between molecular subtypes has yet to be adequately addressed. Here we report that genetic or pharmacological targeting of the epigenetic modifier Ezh2 dramatically hinders metastatic behaviour in both a mouse model of breast cancer and patient-derived xenografts reflective of the Luminal B subtype. We further define a subtype-specific molecular mechanism whereby EZH2 maintains H3K27me3-mediated repression of the FOXC1 gene, thereby inactivating a FOXC1-driven, anti-invasive transcriptional program. We demonstrate that higher FOXC1 is predictive of favourable outcome specifically in Luminal B breast cancer patients and establish the use of EZH2 methyltransferase inhibitors as a viable strategy to block metastasis in Luminal B breast cancer, where options for targeted therapy are limited.

Topics: Animals; Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Doxycycline; Enhancer of Zeste Homolog 2 Protein; Enzyme Inhibitors; Female; Forkhead Transcription Factors; Gene Expression Regulation, Neoplastic; Histones; Humans; Indoles; Lung Neoplasms; Mice; Mice, Knockout; Molecular Targeted Therapy; Protein Processing, Post-Translational; Pyridones; Signal Transduction; Transcription, Genetic; Xenograft Model Antitumor Assays

Kras-driven non-small-cell lung cancers (NSCLCs) are a leading cause of death with limited therapeutic options. Many NSCLCs exhibit high levels of Ezh2, the enzymatic subunit of polycomb repressive complex 2 (PRC2). We tested Ezh2 inhibitors as single agents or before chemotherapy in mice with orthotopic Kras-driven NSCLC grafts, which homogeneously express Ezh2. These tumors display sensitivity to EZH2 inhibition by GSK126 but also amplify an inflammatory program involving signaling through NF-κB and genes residing in PRC2-regulated chromatin. During this process, tumor cells overcome GSK126 antiproliferative effects. We identified oncogenes that may mediate progression through an in vivo RNAi screen aimed at targets of PRC2/NF-κB. An in vitro compound screening linked GSK126-driven inflammation and therapeutic vulnerability in human cells to regulation of RNA synthesis and proteostasis. Interestingly, GSK126-treated NSCLCs in vivo also showed an enhanced response to a combination of nimesulide and bortezomib. Thus, Ezh2 inhibition may restrict cell proliferation and promote defined adaptive responses. Targeting these responses potentially improves outcomes in Kras-driven NSCLCs.

Topics: A549 Cells; Animals; Bortezomib; Carcinoma, Non-Small-Cell Lung; Cell Proliferation; Enhancer of Zeste Homolog 2 Protein; Humans; Indoles; Inflammation; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Proto-Oncogene Proteins p21(ras); Pyridones; Sulfonamides

Small cell lung cancer (SCLC) is a subtype of lung cancer with poor prognosis. Expression array analysis of 23 SCLC cases and 42 normal tissues revealed that EZH2 and other PRC2 members were highly expressed in SCLC. ChIP-seq for H3K27me3 suggested that genes with H3K27me3(+) in SCLC were extended not only to PRC2-target genes in ES cells but also to other target genes such as cellular adhesion-related genes. These H3K27me3(+) genes in SCLC were repressed significantly, and introduction of the most repressed gene JUB into SCLC cell line lead to growth inhibition. Shorter overall survival of clinical SCLC cases correlated to repression of JUB alone, or a set of four genes including H3K27me3(+) genes. Treatment with EZH2 inhibitors, DZNep and GSK126, resulted in growth repression of SCLC cell lines. High PRC2 expression was suggested to contribute to gene repression in SCLC, and may play a role in genesis of SCLC.

Topics: Biomarkers, Tumor; Blotting, Western; Case-Control Studies; Cell Proliferation; Chromatin Immunoprecipitation; Enhancer of Zeste Homolog 2 Protein; Fluorescent Antibody Technique; Gene Expression Profiling; Histones; Humans; Indoles; Jumonji Domain-Containing Histone Demethylases; LIM Domain Proteins; Lung; Lung Neoplasms; Oligonucleotide Array Sequence Analysis; Polycomb Repressive Complex 2; Prognosis; Pyridones; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Small Cell Lung Carcinoma; Survival Rate; Tumor Cells, Cultured