Project description:Small cell lung cancer (SCLC) was defined as a recalcitrant cancer, and novel therapies are urgently needed. Marine natural products (MNP) may bring continuing hope for treatment of SCLC. In this study, 3-bromoascochlorin (BAS), an MNP isolated from the coral-derived fungus Acremonium sclerotigenum GXIMD 02501, was primarily screened out with antiproliferative activity towards SCLC cell lines. Then Western blotting (WB) and flow cytometry were conducted, and we found BAS could induce the apoptosis of H446 and H69AR cells. Besides, BAS could suppress the invasion and migration of H446. In a SCLC xenograft mice model, BAS inhibited the growth of tumor without affecting the body weight of mice. Finally, the underlying mechanisms were preliminarily explored. According to the results of RNA-seq, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and WB, we draw the conclusion that BAS exerted antitumor activity via inhibiting mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinases (ERK) pathway. In short, we discovered an MNP as a potential drug lead against SCLC.
Project description:Small cell lung cancer (SCLC) is an aggressive disease with high mortality. The identification of effective pharmacological strategies to target SCLC biology represents an urgent need. Using a high-throughput cellular screen of a diverse chemical library we observe that SCLC is sensitive to transcription-targeting drugs, and in particular to THZ1, a newly identified covalent inhibitor of cyclin-dependent kinase 7 (CDK7). We find that expression of super-enhancer associated transcription factor genes including MYC family proto-oncogenes and neuroendocrine lineage-specific factors are highly vulnerability to THZ1 treatment. We propose that downregulation of these transcription factors contributes, in part, to SCLC sensitivity to transcriptional inhibitors and that THZ1 represents a novel treatment paradigm for targeted SCLC therapy. ChIP-Seq for H3K27ac in small cell lung cancer lines
Project description:Small cell lung cancer (SCLC) is an aggressive disease with high mortality. The identification of effective pharmacological strategies to target SCLC biology represents an urgent need. Using a high-throughput cellular screen of a diverse chemical library we observe that SCLC is sensitive to transcription-targeting drugs, and in particular to THZ1, a newly identified covalent inhibitor of cyclin-dependent kinase 7 (CDK7). We find that expression of super-enhancer associated transcription factor genes including MYC family proto-oncogenes and neuroendocrine lineage-specific factors are highly vulnerability to THZ1 treatment. We propose that downregulation of these transcription factors contributes, in part, to SCLC sensitivity to transcriptional inhibitors and that THZ1 represents a novel treatment paradigm for targeted SCLC therapy.
Project description:Heterogeneity between tumors is a major barrier to the treatment of small cell lung cancer (SCLC). Identification of molecular markers to characterize and classify tumors can facilitate the diagnosis and development of targeted therapies. Here, we analyzed genomic regions, called super enhancers (SE), across multiple SCLC cell lines and patient-derived xenograft models, and find SE enrichment is sufficient to classify SCLC models into recently defined SCLC molecular subtypes SCLC-A, SCLC-N, and SCLC-P defined by the transcription factors ASCL1, NEUROD1, and POU2F3, respectively. 3D chromatin structure analysis identified genes associated with the SE that assemble into subtype-specific tumor-signatures with genes functioning in diverse processes. Focusing on the SCLC-A subtype, transcription factors NKX2-1 and PROX1 were identified as ASCL1-interacting proteins. All three factors bind overlapping genomic regions within SEs in SCLC-A cell line models. Nevertheless, combined loss of all three factors suppresses growth of SCLC-A similar to that seen with ASCL1 loss alone, continuing to place ASCL1 as a key dependency factor in a subset of SCLC. Focusing on genes co-regulated by the three transcription factors, two SCLC-A subtype-specific cell surface proteins, SCN3A and KCNB2, were identified. Loss of either channel alone did not disrupt SCLC-A growth in vitro, but they may serve as diagnostic tools in subtyping SCLC.
Project description:Heterogeneity between tumors is a major barrier to the treatment of small cell lung cancer (SCLC). Identification of molecular markers to characterize and classify tumors can facilitate the diagnosis and development of targeted therapies. Here, we analyzed genomic regions, called super enhancers (SE), across multiple SCLC cell lines and patient-derived xenograft models, and find SE enrichment is sufficient to classify SCLC models into recently defined SCLC molecular subtypes SCLC-A, SCLC-N, and SCLC-P defined by the transcription factors ASCL1, NEUROD1, and POU2F3, respectively. 3D chromatin structure analysis identified genes associated with the SE that assemble into subtype-specific tumor-signatures with genes functioning in diverse processes. Focusing on the SCLC-A subtype, transcription factors NKX2-1 and PROX1 were identified as ASCL1-interacting proteins. All three factors bind overlapping genomic regions within SEs in SCLC-A cell line models. Nevertheless, combined loss of all three factors suppresses growth of SCLC-A similar to that seen with ASCL1 loss alone, continuing to place ASCL1 as a key dependency factor in a subset of SCLC. Focusing on genes co-regulated by the three transcription factors, two SCLC-A subtype-specific cell surface proteins, SCN3A and KCNB2, were identified. Loss of either channel alone did not disrupt SCLC-A growth in vitro, but they may serve as diagnostic tools in subtyping SCLC.
Project description:Small cell lung cancer (SCLC) is an aggressive disease with high mortality. The identification of effective pharmacological strategies to target SCLC biology represents an urgent need. Using a high-throughput cellular screen of a diverse chemical library we observe that SCLC is sensitive to transcription-targeting drugs, and in particular to THZ1, a newly identified covalent inhibitor of cyclin-dependent kinase 7 (CDK7). We find that expression of super-enhancer associated transcription factor genes including MYC family proto-oncogenes and neuroendocrine lineage-specific factors are highly vulnerability to THZ1 treatment. We propose that downregulation of these transcription factors contributes, in part, to SCLC sensitivity to transcriptional inhibitors and that THZ1 represents a novel treatment paradigm for targeted SCLC therapy. Microarray expression in small cell lung cancer lines treated with DMSO or THZ1
Project description:Small cell lung cancers (SCLC) rapidly resist cytotoxic chemotherapy and immune-checkpoint inhibitor (ICI) treatments. New, non-cross-resistant therapies are thus needed. SCLC cells are committed into neuroendocrine-lineage then maturation-arrested. The corepressor DNA methyltransferase 1 (DNMT1) mediates the maturation-arrests: (i) the repression mark methylated-CpG, written by DNMT1, is retained at suppressed neuroendocrine-lineage genes, even as other repression marks are erased; (ii) DNMT1 is recurrently amplified, while Ten-Eleven-Translocation 2 (TET2) that functionally opposes DNMT1 is deleted; (iii) DNMT1 is recruited into neuroendocrine-lineage master transcription factor (ASCL1, NEUROD1) hubs in SCLC cells; and (iv) DNMT1 knock-down activated ASCL1-target genes and released SCLC cell cycling exits by terminal lineage-maturation, cycling exits that do not require the p53/apoptosis-pathway used by cytotoxic chemotherapy. Inhibiting DNMT1/corepressors with clinical compounds accordingly extended survival of mice with chemo- and ICI-refractory disseminated SCLC. Neuroendocrine-lineage commitment of SCLC cells can thus be leveraged into p53/apoptosis-independent therapy, active against chemo- and ICI-refractory SCLC.
Project description:Small cell lung cancer (SCLC) is a subtype of lung cancer with poor prognosis due to early dissemination and rapid growth. We here analyze gene expression profile of 23 clinical SCLC samples. EZH2 was found to be highly expressed in SCLC samples compared to 42 normal tissues including the normal lung, and other PRC2 members, SUZ12 and EED, were also highly expressed in SCLC. To obtain target genes of PRC2 in SCLC, H3K27me3 mark was mapped in three SCLC cell lines, Lu130, H209 and DMS53, and compared to normal small airway epithelial cells (SAEC). Whereas H3K27me3(+) genes in SAEC were significantly overlapped with PRC-target genes in ES cells (P=1.7x10-31), genes with H3K27me3 in SCLC cell lines but not in SAEC were not significantly overlapped with PRC-target genes in ES cells (P=0.64). These genes with H3K27me3 specifically in SCLC cell lines but not in SAEC showed decreased expression, not only in SCLC cell lines but also in clinical SCLCs, and showed enrichment of GO-terms such as plasma membrane (P=8.1x10-21) and cell adhesion (P=1.7x10-8). Introduction of JUB, a gene showing specific H3K27me3 modification and the strongest repression in the three SCLC cell lines, resulted in repression of cellular growth in DMS53. In clinical SCLC cases, lower JUB level correlated to shorter survival (P=0.002), or a set of PRC target genes (JUB, EPHB4) and marker genes of classic type SCLC (GRP, ASCL1) correlated to shorter survival (P=0.0001) and classified SCLC into two groups with distinct prognosis. Growth of SCLC cell lines was repressed when treated with 3-Deazaneplanocin A, an inhibitor against PRC2. It is suggested that high expression of PRC2 in SCLC contributed to repression of genes including non-PRC-target genes in ES cells, and that the gene repression may play a role in genesis of SCLC. Gene expression in 23 clinical SCLC samples, 42 normal tissue samples, 3 small cell lung cancer (SCLC) cell lines, and normal small airway epithelial cell (SAEC) was analyzed by Affymetrix arrays. This dataset is part of the TransQST collection.