EZH2 promotes progression of small cell lung cancer by suppressing the TGF-β-Smad-ASCL1 pathway

The Lung Cancer Autochthonous Model Gene Expression Database Enables Cross-Study Comparisons of the Transcriptomic Landscapes Across Mouse Models

Lung cancer, the leading cause of cancer mortality, exhibits diverse histologic subtypes and genetic complexities. Numerous preclinical mouse models have been developed to study lung cancer, but data from these models are disparate, siloed, and difficult to compare in a centralized fashion. In this study, we established the Lung Cancer Autochthonous Model Gene Expression Database (LCAMGDB), an extensive repository of 1,354 samples from 77 transcriptomic datasets covering 974 samples from genetically engineered mouse models (GEMM), 368 samples from carcinogen-induced models, and 12 samples from a spontaneous model. Meticulous curation and collaboration with data depositors produced a robust and comprehensive database, enhancing the fidelity of the genetic landscape it depicts. The LCAMGDB aligned 859 tumors from GEMMs with human lung cancer mutations, enabling comparative analysis and revealing a pressing need to broaden the diversity of genetic aberrations modeled in the GEMMs. To accompany this resource, a web application was developed that offers researchers intuitive tools for in-depth gene expression analysis. With standardized reprocessing of gene expression data, the LCAMGDB serves as a powerful platform for cross-study comparison and lays the groundwork for future research, aiming to bridge the gap between mouse models and human lung cancer for improved translational relevance. Significance: The Lung Cancer Autochthonous Model Gene Expression Database (LCAMGDB) provides a comprehensive and accessible resource for the research community to investigate lung cancer biology in mouse models.

Treating human cancer by targeting EZH2

Enhancer of zeste homolog 2 (EZH2), an epigenetic regulator that primarily inhibits downstream gene expression by tri-methylating histone H3, which is usually overexpressed in tumors and participates in many processes such as tumor occurrence and development, invasion, migration, drug resistance, and anti-tumor immunity as an oncogene, making it an important biomarker in cancer therapy. Collectively, several transcription factors and RNAs cooperate to facilitate the elevated expression of EZH2 in cancer. Although the significance of blocking EZH2 in cancer for inhibiting cancer progression is widely recognized, the clinical application of EZH2 inhibitors continues to encounter numerous challenges. In this review, drawing upon our comprehensive understanding of the factual underpinnings of EZH2's role in cancer, we aim to clarify the crucial importance of targeting EZH2 in cancer treatment. Furthermore, we summarize the current research landscape surrounding targeted EZH2 inhibitors and offer insights into potential future applications of these inhibitors.

Molecular Subtypes and Targeted Therapeutic Strategies in Small Cell Lung Cancer: Advances, Challenges, and Future Perspectives

Small cell lung cancer (SCLC) is a highly aggressive malignancy characterized by rapid progression, early metastasis, and high recurrence rates. Historically considered a homogeneous disease, recent multi-omic studies have revealed distinct molecular subtypes driven by lineage-defining transcription factors, including ASCL1, NEUROD1, POU2F3, and YAP1, as well as an inflamed subtype (SCLC-I). These subtypes exhibit unique therapeutic vulnerabilities, thereby paving the way for precision medicine and targeted therapies. Despite recent advances in molecular classification, tumor heterogeneity, plasticity, and therapy resistance continue to hinder clinical success in treating SCLC patients. To this end, novel therapeutic strategies are being explored, including BCL2 inhibitors, DLL3-targeting agents, Aurora kinase inhibitors, PARP inhibitors, and epigenetic modulators. Additionally, immune checkpoint inhibitors (ICIs) show promise, particularly in immune-enriched subtypes of SCLC patients. Hence, a deeper understanding of SCLC subtype characteristics, evolution, and the regulatory mechanisms of subtype-specific transcription factors is crucial for rationally optimizing precision therapy. This knowledge not only facilitates the identification of subtype-specific therapeutic targets, but also provides a foundation for overcoming resistance and developing personalized combination treatment strategies. In the future, the integration of multi-omic data, dynamic molecular monitoring, and precision medicine approaches are expected to further advance the clinical translation of SCLC subtype-specific therapies, ultimately improving patient survival and outcomes.

Therapeutic targeting of TGF-β in lung cancer

Transforming growth factor-β (TGF-β) plays a complex role in lung cancer pathophysiology, initially acting as a tumor suppressor by inhibiting early-stage tumor growth. However, its role evolves in the advanced stages of the disease, where it contributes to tumor progression not by directly promoting cell proliferation but by enhancing epithelial-mesenchymal transition (EMT) and creating a conducive tumor microenvironment. While EMT is typically associated with enhanced migratory and invasive capabilities rather than proliferation per se, TGF-β's influence on this process facilitates the complex dynamics of tumor metastasis. Additionally, TGF-β impacts the tumor microenvironment by interacting with immune cells, a process influenced by genetic and epigenetic changes within tumor cells. This interaction highlights its role in immune evasion and chemoresistance, further complicating lung cancer therapy. This review provides a critical overview of recent findings on TGF-β's involvement in lung cancer, its contribution to chemoresistance, and its modulation of the immune response. Despite the considerable challenges encountered in clinical trials and the development of new treatments targeting the TGF-β pathway, this review highlights the necessity for continued, in-depth investigation into the roles of TGF-β. A deeper comprehension of these roles may lead to novel, targeted therapies for lung cancer. Despite the intricate behavior of TGF-β signaling in tumors and previous challenges, further research could yield innovative treatment strategies.

A semi-supervised weighted SPCA- and convolution KAN-based model for drug response prediction

Motivation

Predicting the response of cell lines to characteristic drugs based on multi-omics gene information has become the core problem of precision oncology. At present, drug response prediction using multi-omics gene data faces the following three main challenges: first, how to design a gene probe feature extraction model with biological interpretation and high performance; second, how to develop multi-omics weighting modules for reasonably fusing genetic data of different lengths and noise conditions; third, how to construct deep learning models that can handle small sample sizes while minimizing the risk of possible overfitting.

Results

We propose an innovative drug response prediction model (NMDP). First, the NMDP model introduces an interpretable semi-supervised weighted SPCA module to solve the feature extraction problem in multi-omics gene data. Next, we construct a multi-omics data fusion framework based on sample similarity networks, bimodal tests, and variance information, which solves the data fusion problem and enables the NMDP model to focus on more relevant genomic data. Finally, we combine a one-dimensional convolution method and Kolmogorov-Arnold networks (KANs) to predict the drug response. We conduct five sets of real data experiments and compare NMDP against seven advanced drug response prediction methods. The results show that NMDP achieves the best performance, with sensitivity and specificity reaching 0.92 and 0.93, respectively-an improvement of 11%-57% compared to other models. Bio-enrichment experiments strongly support the biological interpretation of the NMDP model and its ability to identify potential targets for drug activity prediction.

Enhancer of zeste homolog 2 (EZH2) in endocrine tumors: current knowledge and future directions

INTRODUCTION

Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase that orchestrates gene expression via epigenetic and non-epigenetic mechanisms. EZH2 performs epigenetic functions by methylating histones and/or non-histone proteins and suppressing or activating target genes. Moreover, non-epigenetic functions involve dysregulation of target genes independent of histone methylation, thereby impacting multiple signaling pathways.

AREAS COVERED

EZH2 has emerged as a pivotal player in the initiation of various cancers. EZH2 overexpression facilitated by H3K27me3 is the principal driver. However, the consequent dysregulation of target genes resulting from EZH2 overexpression has emerged as a secondary instigator of tumorigenesis, leading to metastasis and poor prognosis. Further complexity arises from somatic mutations in EZH2 and downstream target genes such as BRAF and RASSF1A. However, understanding its effects on endocrine tumors/cancers remains an underexplored with the potential to significantly enhance clinical outcomes and contribute to human health. Therefore, the present review focuses on the multifaceted functions of EZH2 and its pathophysiological mechanisms in tumor proliferation, with a specific emphasis on endocrine tumors.

EXPERT OPINION

Investigating EZH2 mechanisms and targeting with inhibitors and drugs is an active area of research that could offer a promising avenue for treatment and a better understanding of molecular therapeutic interventions.

β-elemene inhibits tumor-promoting in small cell lung cancer by affecting M2 macrophages and TGF-β

OBJECTIVE

M2 macrophages have been implicated in promoting tumor growth and metastasis in various cancers, including small cell lung cancer (SCLC). This study investigated the role of M2 macrophages in SCLC progression and explored the therapeutic potential of β-elemene, a natural compound, in modulating M2 macrophage-mediated tumor promotion.

METHODS

We differentiated THP-1 monocytes into M2 macrophages using PMA (phorbol 12-myristate 13-acetate), IL-4 (interleukin-4), and IL-13 (interleukin-13). M2 macrophages were co-cultured with the SCLC cell line NCI-H209, and CCK-8, Transwell, and flow cytometry assays were performed. TGF-β expression levels were detected by ELISA. M2 macrophages and NCI-H209 co-cultured cells were treated with β-elemene, or M2 macrophages were transfected with TGF-β shRNA lentivirus, and then co-cultured with NCI-H209 cells. Flow cytometry was used to analyze cell apoptosis. Immunofluorescence staining was performed to assess TGF-β expression.

RESULTS

Our findings demonstrate that M2 macrophages significantly enhance the viability, proliferation, and migration of SCLC cells, and this effect is associated with increased TGF-β expression in SCLC cells co-cultured with M2 macrophages. Furthermore, β-elemene treatment significantly reduced the migration and viability of SCLC cells co-cultured with M2 macrophages. Silencing TGF-β expression in M2 macrophages also suppressed SCLC cell proliferation and migration, suggesting that β-elemene may inhibit the pro-tumorigenic effects of M2 macrophages in SCLC by modulating TGF-β signaling. Immunofluorescence staining revealed that β-elemene treatment significantly reduced TGF-β levels in SCLC cells co-cultured with M2 macrophages, supporting the hypothesis that β-elemene exerts its antitumor activity by modulating the TGF-β pathway.

CONCLUSIONS

Our results suggest that β-elemene has the potential to suppress SCLC development by modulating M2 macrophages and the TGF-β, offering a new therapeutic avenue and potential drug candidate for SCLC treatment.

Recent Advances in the Clinical Translation of Small-Cell Lung Cancer Therapeutics

Small-cell lung cancer (SCLC) is a recalcitrant form of cancer, representing 15% of lung cancer cases globally. SCLC is classified within the range of neuroendocrine pulmonary neoplasms, exhibiting shared morphologic, ultrastructural, immunohistochemical, and molecular genomic features. It is marked by rapid proliferation, a propensity for early metastasis, and an overall poor prognosis. The current conventional therapies involve platinum-etoposide-based chemotherapy in combination with immunotherapy. Nonetheless, the rapid emergence of therapeutic resistance continues to pose substantial difficulties. The genomic profiling of SCLC uncovers significant chromosomal rearrangements along with a considerable mutation burden, typically involving the functional inactivation of the tumor suppressor genes TP53 and RB1. Identifying biomarkers and evaluating new treatments is crucial for enhancing outcomes in patients with SCLC. Targeted therapies such as topoisomerase inhibitors, DLL3 inhibitors, HDAC inhibitors, PARP inhibitors, Chk1 inhibitors, etc., have introduced new therapeutic options for future applications. In this current review, we will attempt to outline the key molecular pathways that play a role in the development and progression of SCLC, together with a comprehensive overview of the most recent advancements in the development of novel targeted treatment strategies, as well as some ongoing clinical trials against SCLC, with the goal of improving patient outcomes.

The therapeutic potential of RNA m(6)A in lung cancer

Lung cancer (LC) is a highly malignant and metastatic form of cancer. The global incidence of and mortality from LC is steadily increasing; the mean 5-year overall survival (OS) rate for LC is less than 20%. This frustrating situation may be attributed to the fact that the pathogenesis of LC remains poorly understood and there is still no cure for mid to advanced LC. Methylation at the N6-position of adenosine (N6mA) of RNA (m(6)A) is widely present in human tissues and organs, and has been found to be necessary for cell development and maintenance of homeostasis. However, numerous basic and clinical studies have demonstrated that RNA m(6)A is deregulated in many human malignancies including LC. This can drive LC malignant characteristics such as proliferation, stemness, invasion, epithelial-mesenchymal transition (EMT), metastasis, and therapeutic resistance. Intriguingly, an increasing number of studies have also shown that eliminating RNA m(6)A dysfunction can exert significant anti-cancer effects on LC such as suppression of cell proliferation and viability, induction of cell death, and reversal of treatment insensitivity. The current review comprehensively discusses the therapeutic potential of RNA m(6)A and its underlying molecular mechanisms in LC, providing useful information for the development of novel LC treatment strategies.

IMPA1-derived inositol maintains stemness in castration-resistant prostate cancer via IMPDH2 activation

Acquisition of prostate cancer stem cells (PCSCs) manifested during androgen ablation therapy (ABT) contributes to castration-resistant prostate cancer (CRPC). However, little is known about the specific metabolites critically orchestrating this process. Here, we show that IMPA1-derived inositol enriched in PCSCs is a key metabolite crucially maintaining PCSCs for CRPC progression and ABT resistance. Notably, conditional Impa1 knockout in the prostate abrogates the pool and properties of PCSCs to orchestrate CRPC progression and prolong the survival of TRAMP mice. IMPA1-derived inositol serves as a cofactor that directly binds to and activates IMPDH2, which synthesizes guanylate nucleotides for maintaining PCSCs with ARlow/- features leading to CRPC progression and ABT resistance. IMPA1/inositol/IMPDH2 axis is upregulated in human prostate cancer, and its overexpression predicts poor survival outcomes. Genetically and pharmacologically targeting the IMPA1/inositol/IMPDH2 axis abrogates CRPC and overcomes ABT resistance in various CRPC xenografts, patient-derived xenograft (PDX) tumor models, and TRAMP mouse models. Our study identifies IMPDH2 as an inositol sensor whose activation by inositol represents a key mechanism for maintaining PCSCs for CRPC and ABT resistance.

Epigenetic regulation of TGF-β and vice versa in cancers - A review on recent developments

This review explores the complex relationship between epigenetic mechanisms and Transforming Growth Factor-beta (TGF-β) signalling pathways in the field of cancer research. The study provides an overview of the latest advancements in understanding the crucial functions of epigenetic alterations, such as DNA methylation, histone modifications, and chromatin remodeling, in significantly impacting the TGF-β signalling pathway. The dynamic epigenetic modifications are essential in determining the behaviour of cancer cells, impacting the interactions with the tumor microenvironment, and affecting the overall process of carcinogenesis. Significant attention is given to Breast cancer, Lung cancer, Liver cancer, Prostate cancer, and Pancreatic cancer. Research has revealed intricate regulatory networks in these cancers, involving long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and histone post-translational modifications. These networks are closely connected to TGF-β signalling. Both findings highlight the significant interaction between epigenetic regulation and TGF-β signalling in cancer. They provide valuable insights that can guide the development of new treatment approaches to target both pathways and prevent cancer growth and metastasis.

EZH2 Activates HTLV-1 bZIP Factor-Mediated TGF-β Signaling in Adult T-Cell Leukemia

Adult T-cell leukemia (ATL) is an aggressive malignancy caused by human T-cell leukemia virus type 1 (HTLV-1) infection. Enhancer of zeste homolog 2 (EZH2) has been implicated in the development and progression of multiple cancers, including virus-induced malignancies. However, the potential function of EZH2 in HTLV-1-induced oncogenesis has not been clearly elucidated. In the present study, we showed that EZH2 was overexpressed and activated in HTLV-1-infected cell lines, potentially due to the activation of EZH2 promoter by HTLV-1 Tax and NF-κB p65 subunit. In addition, we found that EZH2 enhanced the HBZ-induced activation of TGF-β signaling in a histone methyltransferase-independent manner. As a mechanism for these actions, we found that EZH2 targeted Smad3/Smad4 to form a ternary complex, and the association between Smad3 and Smad4 was markedly enhanced in the presence of EZH2. Knockdown of EZH2 in ATL cells indeed repressed the expressions of the TGF-β target genes. In particular, EZH2 synergistically enhanced the HBZ/TGF-β-induced Foxp3 expression. Treatment of 3-Deazaneplanocin A, a specific inhibitor of EZH2 significantly inhibited the Foxp3 expression. Taken together, our results suggest that EZH2 may be involved in the differentiation of regulatory T cells through activating the HBZ-Smad3-TGF-β signaling axis, which is considered to be a key strategy for viral persistence.

Small cell lung cancer profiling: an updated synthesis of subtypes, vulnerabilities, and plasticity

Small cell lung cancer (SCLC) is a devastating disease with high proliferative and metastatic capacity. SCLC has been classified into molecular subtypes based on differential expression of lineage-defining transcription factors. Recent studies have proposed new subtypes that are based on both tumor-intrinsic and -extrinsic factors. SCLC demonstrates substantial intratumoral subtype heterogeneity characterized by highly plastic transcriptional states, indicating that the initially dominant subtype can shift during disease progression and in association with resistance to therapy. Strategies to promote or constrain plasticity and cell fate transitions have nominated novel targets that could prompt the development of more durably effective therapies for patients with SCLC. In this review, we describe the latest advances in SCLC subtype classification and their biological and clinical implications.

Clinical applications of circulating biomarkers in non-small cell lung cancer

Despite recent advances in cancer diagnostics and treatment, the mortality associated with lung cancer is still the highest in the world. Late-stage diagnosis, often accompanied by metastasis, is a major contributor to the high mortality rates, emphasizing the urgent need for reliable and readily accessible diagnostic tools that can detect biomarkers unique to lung cancer. Circulating factors, such as circulating tumor DNA and extracellular vesicles, from liquid biopsy have been recognized as diagnostic or prognostic markers in lung cancer. Numerous clinical studies are currently underway to investigate the potential of circulating tumor DNA, circulating tumor RNA, exosomes, and exosomal microRNA within the context of lung cancer. Those clinical studies aim to address the poor diagnostics and limited treatment options for lung cancer, with the ultimate goal of developing clinical markers and personalized therapies. In this review, we discuss the roles of each circulating factor, its current research status, and ongoing clinical studies of circulating factors in non-small cell lung cancer. Additionally, we discuss the circulating factors specifically found in lung cancer stem cells and examine approved diagnostic assays designed to detect circulating biomarkers in lung cancer patients.

An Overview of Altered Pathways Associated with Sensitivity to Platinum-Based Chemotherapy in Neuroendocrine Tumors: Strengths and Prospects

Neuroendocrine neoplasms (NENs) are a diverse group of malignancies with a shared phenotype but varying prognosis and response to current treatments. Based on their morphological features and rate of proliferation, NENs can be classified into two main groups with a distinct clinical behavior and response to treatment: (i) well-differentiated neuroendocrine tumors (NETs) or carcinoids (with a low proliferation rate), and (ii) poorly differentiated small- or large-cell neuroendocrine carcinomas (NECs) (with a high proliferation rate). For certain NENs (such as pancreatic tumors, higher-grade tumors, and those with DNA damage repair defects), chemotherapy is the main therapeutic approach. Among the different chemotherapic agents, cisplatin and carboplatin, in combination with etoposide, have shown the greatest efficacy in treating NECs compared to NETs. The cytotoxic effects of cisplatin and carboplatin are primarily due to their binding to DNA, which interferes with normal DNA transcription and/or replication. Consistent with this, NECs, which often have mutations in pathways involved in DNA repair (such as Rb, MDM2, BRCA, and PTEN), have a high response to platinum-based chemotherapy. Identifying mutations that affect molecular pathways involved in the initiation and progression of NENs can be crucial in predicting the response to platinum chemotherapy. This review aims to highlight targetable mutations that could serve as predictors of therapeutic response to platinum-based chemotherapy in NENs.

TGF-β signaling: critical nexus of fibrogenesis and cancer

The transforming growth factor-beta (TGF-β) signaling pathway is a vital regulator of cell proliferation, differentiation, apoptosis, and extracellular matrix production. It functions through canonical SMAD-mediated processes and noncanonical pathways involving MAPK cascades, PI3K/AKT, Rho-like GTPases, and NF-κB signaling. This intricate signaling system is finely tuned by interactions between canonical and noncanonical pathways and plays key roles in both physiologic and pathologic conditions including tissue homeostasis, fibrosis, and cancer progression. TGF-β signaling is known to have paradoxical actions. Under normal physiologic conditions, TGF-β signaling promotes cell quiescence and apoptosis, acting as a tumor suppressor. In contrast, in pathological states such as inflammation and cancer, it triggers processes that facilitate cancer progression and tissue remodeling, thus promoting tumor development and fibrosis. Here, we detail the role that TGF-β plays in cancer and fibrosis and highlight the potential for future theranostics targeting this pathway.

Deciphering lung adenocarcinoma evolution: Integrative single-cell genomics identifies the prognostic lung progression associated signature

We employed single-cell analysis techniques, specifically the inferCNV method, to dissect the complex progression of lung adenocarcinoma (LUAD) from adenocarcinoma in situ (AIS) through minimally invasive adenocarcinoma (MIA) to invasive adenocarcinoma (IAC). This approach enabled the identification of Cluster 6, which was significantly associated with LUAD progression. Our comprehensive analysis included intercellular interaction, transcription factor regulatory networks, trajectory analysis, and gene set variation analysis (GSVA), leading to the development of the lung progression associated signature (LPAS). Interestingly, we discovered that the LPAS not only accurately predicts the prognosis of LUAD patients but also forecasts genomic alterations, distinguishes between 'cold' and 'hot' tumours, and identifies potential candidates suitable for immunotherapy. PSMB1, identified within Cluster 6, was experimentally shown to significantly enhance cancer cell invasion and migration, highlighting the clinical relevance of LPAS in predicting LUAD progression and providing a potential target for therapeutic intervention. Our findings suggest that LPAS offers a novel biomarker for LUAD patient stratification, with significant implications for improving prognostic accuracy and guiding treatment decisions.

Landscape and Treatment Options of Shapeshifting Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a deadly neuroendocrine malignancy, notorious for its rapid tumor growth, early metastasis, and relatively "cold" immune environment. Only standard chemotherapies and a few immune checkpoint inhibitors have been approved for SCLC treatment, revealing an urgent need for novel therapeutic approaches. Moreover, SCLC has been recently recognized as a malignancy with high intratumoral and intertumoral heterogeneity, which explains the modest response rate in some patients and the early relapse. Molecular subtypes defined by the expression of lineage-specific transcription factors (ASCL1, NEUROD1, POU2F3, and, in some studies, YAP1) or immune-related genes display different degrees of neuroendocrine differentiation, immune cell infiltration, and response to treatment. Despite the complexity of this malignancy, a few biomarkers and targets have been identified and many promising drugs are currently undergoing clinical trials. In this review, we integrate the current progress on the genomic landscape of this shapeshifting malignancy, the characteristics and treatment vulnerabilities of each subtype, and promising drugs in clinical phases.

Challenges and opportunities in the immunotherapy era: balancing expectations with hope in small-cell lung cancer

Small-cell lung cancer (SCLC) is a biologically aggressive subtype of lung cancer, a lethal disease characterized by rapid tumor growth, early relapse, a strong tendency for early widespread metastasis, and high genomic instability, making it a formidable foe in modern oncology practice. While the management of non-SCLC has been revolutionized in the era of immunotherapy, progress in SCLC has been more muted. Recent randomized phase III clinical trials have combined programmed death ligand-1 inhibitors to a chemotherapy backbone and demonstrated improved survival; however, the absolute benefit observed is short months. There is an undeniable urgent need for better responses, better agents, novel therapeutic approaches, and more rational, biomarker-driven clinical trials in SCLC. In this review, we discuss the rationale and current understanding of the biology of SCLC in the modern era of immunotherapy, discuss recent advances in front-line immunotherapeutic approaches that have changed clinical practice globally, provide an overview of some of the challenges and limitations that have staggered immune checkpoint blockade in SCLC, and explore some of the novel immunotherapeutic approaches currently being investigated.

The stromal microenvironment endows pancreatic neuroendocrine tumors with spatially specific invasive and metastatic phenotypes

Cancer-associated fibroblasts (CAFs) play an important role in a variety of cancers. However, the role of tumor stroma in nonfunctional pancreatic neuroendocrine tumors (NF-PanNETs) is often neglected. Profiling the heterogeneity of CAFs can reveal the causes of malignant phenotypes in NF-PanNETs. Here, we found that patients with high stromal proportion had poor prognosis, especially for that with infiltrating stroma (stroma and tumor cells that presented an infiltrative growth pattern and no regular boundary). In addition, myofibroblastic CAFs (myCAFs), characterized by FAP+ and α-SMAhigh, were spatially closer to tumor cells and promoted the EMT and tumor growth. Intriguingly, only tumor cells which were spatially closer to myCAFs underwent EMT. We further elucidated that myCAFs stimulate TGF-β expression in nearby tumor cells. Then, TGF-β promoted the EMT in adjacent tumor cells and promoted the expression of myCAFs marker genes in tumor cells, resulting in distant metastasis. Our results indicate that myCAFs cause spatial heterogeneity of EMT, which accounts for liver metastasis of NF-PanNETs. The findings of this study might provide possible targets for the prevention of liver metastasis.

Small cells - big issues: biological implications and preclinical advancements in small cell lung cancer

Current treatment guidelines refer to small cell lung cancer (SCLC), one of the deadliest human malignancies, as a homogeneous disease. Accordingly, SCLC therapy comprises chemoradiation with or without immunotherapy. Meanwhile, recent studies have made significant advances in subclassifying SCLC based on the elevated expression of the transcription factors ASCL1, NEUROD1, and POU2F3, as well as on certain inflammatory characteristics. The role of the transcription regulator YAP1 in defining a unique SCLC subset remains to be established. Although preclinical analyses have described numerous subtype-specific characteristics and vulnerabilities, the so far non-existing clinical subtype distinction may be a contributor to negative clinical trial outcomes. This comprehensive review aims to provide a framework for the development of novel personalized therapeutic approaches by compiling the most recent discoveries achieved by preclinical SCLC research. We highlight the challenges faced due to limited access to patient material as well as the advances accomplished by implementing state-of-the-art models and methodologies.

Establishment of ganglioside GD2-expressing extranodal NK/T-cell lymphoma cell line with scRNA-seq analysis

Extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKL), is characterized by Epstein-Barr virus infection and poor prognosis. We established a novel cell line, ENKL-J1, from bone marrow cells of an ENKL patient. We found that ENKL-J1 cells express the ganglioside GD2 (GD2) and that GD2-directed chimeric antigen receptor T cells exhibit cytotoxicity against ENKL-J1 cells, indicating that GD2 would be a suitable target of GD2-expressing ENKL cells. Targeted next-generation sequencing revealed TP53 and TET2 variants in ENKL-J1 cells. Furthermore, single-cell RNA sequencing in ENKL-J1 cells showed high gene-expression levels in the oncogenic signaling pathways JAK-STAT, NF-κB, and MAPK. Genes related to multidrug resistance (ABCC1), tumor suppression (ATG5, CRYBG1, FOXO3, TP53, MGA), anti-apoptosis (BCL2, BCL2L1), immune checkpoints (CD274, CD47), and epigenetic regulation (DDX3X, EZH2, HDAC2/3) also were expressed at high levels. The molecular targeting agents eprenetapopt, tazemetostat, and vorinostat efficiently induced apoptosis in ENKL-J1 cells in vitro. Furthermore, GD2-directed chimeric antigen receptor T cells showed cytotoxicity against ENKL-J1 cells in vivo. These findings not only contribute to understanding the molecular and genomic characteristics of ENKL; they also suggest new treatment options for patients with advanced or relapsed ENKL.

Actionable Driver Events in Small Cell Lung Cancer

Small cell lung cancer (SCLC) stands out as the most aggressive form of lung cancer, characterized by an extremely high proliferation rate and a very poor prognosis, with a 5-year survival rate that falls below 7%. Approximately two-thirds of patients receive their diagnosis when the disease has already reached a metastatic or extensive stage, leaving chemotherapy as the remaining first-line treatment option. Other than the recent advances in immunotherapy, which have shown moderate results, SCLC patients cannot yet benefit from any approved targeted therapy, meaning that this cancer remains treated as a uniform entity, disregarding intra- or inter-tumoral heterogeneity. Continuous efforts and technological improvements have enabled the identification of new potential targets that could be used to implement novel therapeutic strategies. In this review, we provide an overview of the most recent approaches for SCLC treatment, providing an extensive compilation of the targeted therapies that are currently under clinical evaluation and inhibitor molecules with promising results in vitro and in vivo.

Review: Targeting EZH2 in neuroblastoma

Neuroblastoma is one of the commonest extra-cranial pediatric tumors, and accounts for over 15% of all childhood cancer mortality. Risk stratification for children with neuroblastoma is based on age, stage, histology, and tumor cytogenetics. The majority of patients are considered to have high-risk neuroblastoma, for which the long-term survival is less than 50%. Current treatments combine surgical resection, chemotherapy, stem cell transplantation, radiotherapy, anti-GD2 based immunotherapy as well as the differentiating agent isotretinoin. Despite the intensive multimodal therapies applied, there are high relapse rates, and recurrent disease is often resistant to further therapy. Enhancer of Zeste Homolog 2 (EZH2), a catalytic subunit of Polycomb Repressive Complex 2 (PRC2), is a histone methyltransferase that represses transcription through trimethylation of lysine residue K27 on histone H3 (H3K27me3). It is responsible for epigenetic repression of transcription, making EZH2 an essential regulator for cell differentiation. Overexpression of EZH2 has been shown to promote tumorigenesis, cancer cell proliferation and prevent tumor cells from differentiating in a number of cancers. Therefore, research has been ongoing for the past decade, developing treatments that target EZH2 in neuroblastoma. This review summarises the role of EZH2 in neuroblastoma and evaluates the latest research findings on the therapeutic potential of targeting EZH2 in the treatment of neuroblastoma.

Mammalian SWI/SNF chromatin remodeling complexes promote tyrosine kinase inhibitor resistance in EGFR-mutant lung cancer

Acquired resistance to tyrosine kinase inhibitors (TKI), such as osimertinib used to treat EGFR-mutant lung adenocarcinomas, limits long-term efficacy and is frequently caused by non-genetic mechanisms. Here, we define the chromatin accessibility and gene regulatory signatures of osimertinib sensitive and resistant EGFR-mutant cell and patient-derived models and uncover a role for mammalian SWI/SNF chromatin remodeling complexes in TKI resistance. By profiling mSWI/SNF genome-wide localization, we identify both shared and cancer cell line-specific gene targets underlying the resistant state. Importantly, genetic and pharmacologic disruption of the SMARCA4/SMARCA2 mSWI/SNF ATPases re-sensitizes a subset of resistant models to osimertinib via inhibition of mSWI/SNF-mediated regulation of cellular programs governing cell proliferation, epithelial-to-mesenchymal transition, epithelial cell differentiation, and NRF2 signaling. These data highlight the role of mSWI/SNF complexes in supporting TKI resistance and suggest potential utility of mSWI/SNF inhibitors in TKI-resistant lung cancers.

Small Cell Lung Cancer: Emerging Targets and Strategies for Precision Therapy

Small cell lung cancer is an aggressive subtype of lung cancer with limited treatment options. Precision medicine has revolutionized cancer treatment for many tumor types but progress in SCLC has been slower due to the lack of targetable biomarkers. This review article provides an overview of emerging strategies for precision therapy in SCLC. Targeted therapies include targeted kinase inhibitors, monoclonal antibodies, angiogenesis inhibitors, antibody-drug conjugates, PARP inhibitors, and epigenetic modulators. Angiogenesis inhibitors and DNA-damaging agents, such as PARP and ATR inhibitors, have been explored in SCLC with limited success to date although trials are ongoing. The potential of targeting DLL3, a NOTCH ligand, through antibody-drug conjugates, bispecific T-cell engagers, and CAR T-cell therapy, has opened up new therapeutic options moving forward. Additionally, new research in epigenetic therapeutics in reversing transcriptional repression, modulating anti-tumor immunity, and utilizing antibody-drug conjugates to target cell surface-specific targets in SCLC are also being investigated. While progress in precision therapy for SCLC has been challenging, recent advancements provide optimism for improved treatment outcomes. However, several challenges remain and will need to be addressed, including drug resistance and tumor heterogeneity. Further research and biomarker-selected clinical trials are necessary to develop effective precision therapies for SCLC patients.

Inhibition of EZH2 alleviates SAHA-induced senescence-associated secretion phenotype in small cell lung cancer cells

Chemotherapy has been widely used in small cell lung cancer (SCLC) treatment in the past decades. However, SCLC is easy to recur after chemotherapy. The senescence of cancer cells during chemotherapy is one of the effective therapeutic strategies to inhibit the progression of cancer. Nevertheless, the senescence-associated secretion phenotype (SASP) promotes chronic inflammation of the cancer microenvironment and further accelerates the progression of tumors. Therefore, inducing the senescence of cancer cells and inhibiting the production of SASP factors during anticancer treatment have become effective therapeutic strategies to improve the anticancer effect of drugs. Here we reported that SCLC cells treated with an FDA-approved HDAC inhibitor SAHA underwent senescence and displayed remarkable SASP. In particular, SAHA promoted the formation of cytoplasmic chromatin fragments (CCFs) in SCLC cells. The increased CCFs in SAHA-treated SCLC cells were related to nuclear porin Tpr, which activated the cGAS-STING pathway, and promoted the secretion of SASP in cancer cells. Inhibition of EZH2 suppressed the increase of CCFs in SAHA-treated SCLC cells, weakened the production of SASP, and increased the antiproliferative effect of SAHA. Overall, our work affords new insight into the secretion of SASP in SCLC and establishes a foundation for constructing a new therapeutic strategy for SCLC patients.

The Transcriptional and Epigenetic Landscape of Cancer Cell Lineage Plasticity

Lineage plasticity, a process whereby cells change their phenotype to take on a different molecular and/or histologic identity, is a key driver of cancer progression and therapy resistance. Although underlying genetic changes within the tumor can enhance lineage plasticity, it is predominantly a dynamic process controlled by transcriptional and epigenetic dysregulation. This review explores the transcriptional and epigenetic regulators of lineage plasticity and their interplay with other features of malignancy, such as dysregulated metabolism, the tumor microenvironment, and immune evasion. We also discuss strategies for the detection and treatment of highly plastic tumors.

SIGNIFICANCE

Lineage plasticity is a hallmark of cancer and a critical facilitator of other oncogenic features such as metastasis, therapy resistance, dysregulated metabolism, and immune evasion. It is essential that the molecular mechanisms of lineage plasticity are elucidated to enable the development of strategies to effectively target this phenomenon. In this review, we describe key transcriptional and epigenetic regulators of cancer cell plasticity, in the process highlighting therapeutic approaches that may be harnessed for patient benefit.

Cancer Cell-Intrinsic Alterations Associated with an Immunosuppressive Tumor Microenvironment and Resistance to Immunotherapy in Lung Cancer

Despite the great clinical success of immunotherapy in lung cancer patients, only a small percentage of them (<40%) will benefit from this therapy alone or combined with other strategies. Cancer cell-intrinsic and cell-extrinsic mechanisms have been associated with a lack of response to immunotherapy. The present study is focused on cancer cell-intrinsic genetic, epigenetic, transcriptomic and metabolic alterations that reshape the tumor microenvironment (TME) and determine response or refractoriness to immune checkpoint inhibitors (ICIs). Mutations in KRAS, SKT11(LKB1), KEAP1 and TP53 and co-mutations of these genes are the main determinants of ICI response in non-small-cell lung cancer (NSCLC) patients. Recent insights into metabolic changes in cancer cells that impose restrictions on cytotoxic T cells and the efficacy of ICIs indicate that targeting such metabolic restrictions may favor therapeutic responses. Other emerging pathways for therapeutic interventions include epigenetic modulators and DNA damage repair (DDR) pathways, especially in small-cell lung cancer (SCLC). Therefore, the many potential pathways for enhancing the effect of ICIs suggest that, in a few years, we will have much more personalized medicine for lung cancer patients treated with immunotherapy. Such strategies could include vaccines and chimeric antigen receptor (CAR) cells.

The pharmacological and biological importance of EZH2 signaling in lung cancer

Up to 18% of cancer-related deaths worldwide are attributed to lung tumor and global burden of this type of cancer is ascending. Different factors are responsible for development of lung cancer such as smoking, environmental factors and genetic mutations. EZH2 is a vital protein with catalytic activity and belongs to PCR2 family. EZH2 has been implicated in regulating gene expression by binding to promoter of targets. The importance of EZH2 in lung cancer is discussed in current manuscript. Activation of EZH2 significantly elevates the proliferation rate of lung cancer. Furthermore, metastasis and associated molecular mechanisms including EMT undergo activation by EZH2 in enhancing the lung cancer progression. The response of lung cancer to therapy can be significantly diminished due to EZH2 upregulation. Since EZH2 increases tumor progression, anti-cancer agents suppressing its expression reduce malignancy. In spite of significant effort in understanding modulatory function of EZH2 on other pathways, it appears that EZH2 can be also regulated and controlled by other factors that are described in current review. Therefore, translating current findings to clinic can improve treatment and management of lung cancer patients.

Neuroendocrine Neoplasms: Genetics and Epigenetics

Neuroendocrine neoplasms (NENs) are a group of rare, heterogeneous tumors of neuroendocrine cell origin, affecting a range of different organs. The clinical management of NENs poses significant challenges, as tumors are often diagnosed at an advanced stage where overall survival remains poor with current treatment regimens. In addition, a host of complex and often unique molecular changes underpin the pathobiology of each NEN subtype. Exploitation of the unique genetic and epigenetic signatures driving each NEN subtype provides an opportunity to enhance the diagnosis, treatment, and monitoring of NEN in an emerging era of individualized medicine.

Targeting YAP1/TAZ in nonsmall-cell lung carcinoma: From molecular mechanisms to precision medicine

Accumulating evidence has underscored the importance of the Hippo-YAP1 signaling in lung tissue homeostasis, whereas its deregulation induces tumorigenesis. YAP1 and its paralog TAZ are the key downstream effectors tightly controlled by the Hippo pathway. YAP1/TAZ exerts oncogenic activities by transcriptional regulation via physical interaction with TEAD transcription factors. In solid tumors, Hippo-YAP1 crosstalks with other signaling pathways such as Wnt/β-catenin, receptor tyrosine kinase cascade, Notch and TGF-β to synergistically drive tumorigenesis. As YAP1/TAZ expression is significantly correlated with unfavorable outcomes for the patients, small molecules have been developed for targeting YAP1/TAZ to get a therapeutic effect. In this review, we summarize the recent findings on the deregulation of Hippo-YAP1 pathway in nonsmall cell lung carcinoma, discuss the molecular mechanisms of its dysregulation in leading to tumorigenesis, explore the therapeutic strategies for targeting YAP1/TAZ, and provide the research directions for deep investigation. We believe that detailed delineation of Hippo-YAP1 regulation in tumorigenesis provides novel insight for accurate therapeutic intervention.

The epigenome and the many facets of cancer drug tolerance

The use of chemotherapeutic agents and the development of new cancer therapies over the past few decades has consequently led to the emergence of myriad therapeutic resistance mechanisms. Once thought to be explicitly driven by genetics, the coupling of reversible sensitivity and absence of pre-existing mutations in some tumors opened the way for discovery of drug-tolerant persisters (DTPs): slow-cycling subpopulations of tumor cells that exhibit reversible sensitivity to therapy. These cells confer multi-drug tolerance, to targeted and chemotherapies alike, until the residual disease can establish a stable, drug-resistant state. The DTP state can exploit a multitude of distinct, yet interlaced, mechanisms to survive otherwise lethal drug exposures. Here, we categorize these multi-faceted defense mechanisms into unique Hallmarks of Cancer Drug Tolerance. At the highest level, these are comprised of heterogeneity, signaling plasticity, differentiation, proliferation/metabolism, stress management, genomic integrity, crosstalk with the tumor microenvironment, immune escape, and epigenetic regulatory mechanisms. Of these, epigenetics was both one of the first proposed means of non-genetic resistance and one of the first discovered. As we describe in this review, epigenetic regulatory factors are involved in most facets of DTP biology, positioning this hallmark as an overarching mediator of drug tolerance and a potential avenue to novel therapies.

Squamous cell lung cancer: Current landscape and future therapeutic options

Squamous cell lung cancers (lung squamous cell carcinomas [LUSCs]) are associated with high mortality and a lack of therapies specific to this disease. Although recurrent molecular aberrations are present in LUSCs, efforts to develop targeted therapies against receptor tyrosine kinases, signaling transduction, and cell cycle checkpoints in LUSCs were met with significant challenges. The present therapeutic landscape focuses on epigenetic therapies to modulate the expression of lineage-dependent survival pathways and undruggable oncogenes. Another important therapeutic approach is to exploit metabolic vulnerabilities unique to LUSCs. These novel therapies may synergize with immune checkpoint inhibitors in the right therapeutic context. For example, the recognition that alterations in KEAP1-NFE2L2 in LUSCs affected antitumor immune responses created unique opportunities for targeted, metabolic, and immune combinations. This article provides a perspective on how lessons learned from the past influence the current therapeutic landscape and opportunities for future drug development for LUSCs.

The Upregulation of HAS2-AS1 Relates to the Granulosa Cell Dysfunction by Repressing TGF-β Signaling and Upregulating HAS2

HAS2 antisense RNA 1 (HAS2-AS1) is a long noncoding RNA that has increased expression in mature granulosa cells (GCs) and contributes to cumulus expansion by regulating HAS2 expression. However, the roles of HAS2-AS1 during the pathological process of polycystic ovary syndrome (PCOS) are still unclear. This study investigated the roles of HAS2-AS1 in patients with PCOS. Here, a significant upregulation of HAS2-AS1 was found in the primary GCs from patients with PCOS, which was positively correlated with the level of the protein HAS2. The knockdown of HAS2 restored the upregulation of HAS2-AS1 in promoting migration but could not restore the effects of HAS2-AS1 overexpression in promoting proliferation and repressing apoptosis. Transforming growth factor β (TGF-β) upregulated HAS2-AS1 levels, while HAS2-AS1 functioned as a feedback inhibition factor repressing TGF-β signaling by inhibiting TGF-β receptor type 2 (TGFBR2) expression. HAS2-AS1 bonded with EZH2 and guided the polycomb complex 2 to the TGFBR2 promoter region. HAS2-AS1 overexpression induced H3K27 hypermethylation in the TGFBR2 promoter region and then repressed TGFBR2 transcription in KGN cells and primary GCs. In conclusion, we identified for the first time that HAS2-AS1 is upregulated in patients with PCOS and represses TGF-β signaling via inducing TGFBR2 promoter region hypermethylation, which allowed us to explore the pathological processes of PCOS.

Classical epithelial-mesenchymal transition (EMT) and alternative cell death process-driven blebbishield metastatic-witch (BMW) pathways to cancer metastasis

Metastasis is a pivotal event that accelerates the prognosis of cancer patients towards mortality. Therapies that aim to induce cell death in metastatic cells require a more detailed understanding of the metastasis for better mitigation. Towards this goal, we discuss the details of two distinct but overlapping pathways of metastasis: a classical reversible epithelial-to-mesenchymal transition (hybrid-EMT)-driven transport pathway and an alternative cell death process-driven blebbishield metastatic-witch (BMW) transport pathway involving reversible cell death process. The knowledge about the EMT and BMW pathways is important for the therapy of metastatic cancers as these pathways confer drug resistance coupled to immune evasion/suppression. We initially discuss the EMT pathway and compare it with the BMW pathway in the contexts of coordinated oncogenic, metabolic, immunologic, and cell biological events that drive metastasis. In particular, we discuss how the cell death environment involving apoptosis, ferroptosis, necroptosis, and NETosis in BMW or EMT pathways recruits immune cells, fuses with it, migrates, permeabilizes vasculature, and settles at distant sites to establish metastasis. Finally, we discuss the therapeutic targets that are common to both EMT and BMW pathways.

Targeting EZH2 to overcome the resistance to immunotherapy in lung cancer

Unleashing the immune system to fight cancer has been a major breakthrough in cancer therapeutics since 2014 when anti-PD-1 antibodies (pembrolizumab and nivolumab) were approved for patients with metastatic melanoma. Therapeutic indications have rapidly expanded for many types of advanced cancer, including lung cancer. A variety of antibodies targeting the PD-1/PD-L1 checkpoint are contributing to this paradigm shift. The field now confronts two salient challenges: first, to improve the therapeutic outcome given the low response rate across the histologies; second, to identify biomarkers for improved patient selection. Pre-clinical and clinical studies are underway to evaluate combinatorial treatments to improve the therapeutic outcome paired with correlative studies to identify the factors associated with response and resistance. One of the emerging strategies is to combine epigenetic modifiers with immune checkpoint blockade (ICB) based on the evidence that targeting epigenetic elements can enhance anti-tumor immunity by reshaping the tumor microenvironment (TME). We will briefly review pleotropic biological functions of enhancer of zeste homolog 2 (EZH2), the enzymatic subunit of polycomb repressive complex 2 (PRC2), clinical developments of oral EZH2 inhibitors, and potentially promising approaches to combine EZH2 inhibitors and PD-1 blockade for patients with advanced solid tumors, focusing on lung cancer.

Heterogeneity of neuroendocrine transcriptional states in metastatic small cell lung cancers and patient-derived models

Molecular subtypes of small cell lung cancer (SCLC) defined by the expression of key transcription regulators have recently been proposed in cell lines and limited number of primary tumors. The clinical and biological implications of neuroendocrine (NE) subtypes in metastatic SCLC, and the extent to which they vary within and between patient tumors and in patient-derived models is not known. We integrate histology, transcriptome, exome, and treatment outcomes of SCLC from a range of metastatic sites, revealing complex intra- and intertumoral heterogeneity of NE differentiation. Transcriptomic analysis confirms previously described subtypes based on ASCL1, NEUROD1, POU2F3, YAP1, and ATOH1 expression, and reveal a clinical subtype with hybrid NE and non-NE phenotypes, marked by chemotherapy-resistance and exceedingly poor outcomes. NE tumors are more likely to have RB1, NOTCH, and chromatin modifier gene mutations, upregulation of DNA damage response genes, and are more likely to respond to replication stress targeted therapies. In contrast, patients preferentially benefited from immunotherapy if their tumors were non-NE. Transcriptional phenotypes strongly skew towards the NE state in patient-derived model systems, an observation that was confirmed in paired patient-matched tumors and xenografts. We provide a framework that unifies transcriptomic and genomic dimensions of metastatic SCLC. The marked differences in transcriptional diversity between patient tumors and model systems are likely to have implications in development of novel therapeutic agents.

Prognostic Implications of Molecular Subtypes in Primary Small Cell Lung Cancer and Their Correlation With Cancer Immunity

Introduction

Small cell lung cancer (SCLC) has recently been characterized as heterogeneous tumors due to consensus nomenclature for distinct molecular subtypes on the basis of differential expression of four transcription markers (ASCL1, NEUROD1, POU2F3, and YAP1). It is necessary to validate molecular subtype classification in primary SCLC tumors by immunohistochemical (IHC) staining and investigate its relevance to survival outcomes.

Methods

Using a large number of surgically resected primary SCLC tumors, we assessed the mRNA and protein levels of the four subtype markers (ASCL1, NEUROD1, POU2F3 and YAP1) in two independent cohorts, respectively. Next, molecular subtypes defined by the four subtype markers was conducted to identify the association with clinicopathologic characteristics, survival outcomes, the expression of classic neuroendocrine markers, and molecules related to tumor immune microenvironment.

Results

Samples were categorized into four subtypes based on the relative expression levels of the four subtype markers, yielding to ASCL1, NEUROD1, POU2F3 and YAP1 subtypes, respectively. The combined neuroendocrine differentiation features were more prevalent in either ASCL1 or NEUROD1 subtypes. Kaplan-Meier analyses found that patients with tumors of the YAP1 subtype and ASCL1 subtype obtained the best and worst prognosis on both mRNA and IHC levels, respectively. Based on multivariate Cox proportional-hazards regression model, molecular subtype classification determined by IHC was identified as an independent indicator for survival outcomes in primary SCLC tumors. Correlation analyses indicated that the four subtype markers in SCLC cancer cells were interacted with its tumor immune microenvironment. Specifically, tumors positive for YAP1 was associated with fewer CTLA4⁺ T cell infiltration, while more immune-inhibitory receptors (FoxP3,PD1, and CTLA4) and fewer immune-promoting receptor (CD8) were found in tumors positive for ASCL1.

Conclusions

We validated the new molecular subtype classification and clinical relevance on both mRNA and protein levels from primary SCLC tumors. The molecular subtypes determined by IHC could be a pre-selected effective biomarker significantly influenced on prognosis in patients with SCLC, which warrants further studies to provide better preventative and therapeutic options for distinct molecular subtypes.

Update 2021: Management of Small Cell Lung Cancer

BACKGROUND

Accounting for 14% of lung cancer, small cell lung cancer (SCLC) is a highly aggressive neuroendocrine malignancy with rapid proliferation, early spread, and poor survival.

AIM AND METHODS

We provide an overview of recent advances regarding SCLC pathogenesis, subtypes, and treatment development through literature review of key trials.

RESULTS

There are no validated biomarkers or approved targeted treatments for this overly heterogeneous disease, but recent analyses have identified some promising targets and four major subtypes which may carry unique therapeutic vulnerabilities in SCLC. Treatment wise, only a third of patients present with limited stage SCLC, which can be managed with a combined modality approach with curative intent (usually chemo-radiotherapy, but in some eligible patients, surgery followed by systemic treatment). For advanced or extensive stage SCLC, combined chemotherapy (platinum-etoposide) and immunotherapy (atezolizumab or durvalumab during and after chemotherapy) has become the new standard front-line treatment, with modest improvement in overall survival. In the second-line setting, for disease relapse ≤ 6 months, topotecan, lurbinectedin, and clinical trials are reasonable treatment options; for disease relapse > 6 months, original regimen, topotecan or lurbinectedin can be considered. Moreover, Trilaciclib, a CD4/CD6 inhibitor, was recently FDA-approved to decrease the incidence of chemotherapy-related myelosuppression in SCLC patients.

CONCLUSIONS

While modest improvements in survival have been made especially in the metastatic setting with chemo-immunotherapy, further research in understanding the biology of SCLC is warranted to develop biomarker-driven therapeutic strategies and combinational approaches for this aggressive disease.

A mesenchymal-like subpopulation in non-neuroendocrine SCLC contributes to metastasis

Small cell lung cancer (SCLC) is the most aggressive lung cancer with high heterogeneity. Mouse SCLC cells derived from the Rb1L/L/Trp53L/L (RP) autochthonous mouse model grew as adhesion or suspension in cell culture, and the adhesion cells are defined as non-neuroendocrine (non-NE) SCLC cells. Here, we uncover the heterogenous subpopulations within the non-NE cells and referred to them as mesenchymal-like (Mes) and epithelial-like (Epi) SCLC cells. The Mes cells have increased capability to form colonies in soft agar and harbored stronger metastatic capability in vivo when compared with the Epi cells. Gene Set Enrichment Analysis reveals that the transforming growth factor (TGF)-β signaling is enriched in the Mes cells. Importantly, inhibition of the TGF-β signaling through ectopic expression of dominant-negative Tgfbr2 (Tgfbr2-DN) or treatment with Tgfbr1 inhibitor SD-208 consistently abrogates tumor metastasis in nude mouse allograft assays. Moreover, genetic deletion of Tgfbr2 or Smad4, the key components of the TGF-β signaling pathway, dramatically attenuates SCLC metastasis in the RP autochthonous mouse model. Collectively, our results uncover the high heterogeneity in non-NE SCLC cells and highlight an important role of TGF-β signaling in promoting SCLC metastasis.

Genome-wide analysis of DNA methylation identifies the apoptosis-related gene UQCRH as a tumor suppressor in renal cancer

DNA hypermethylation is frequently observed in clear cell renal cell carcinoma (ccRCC) and correlates with poor clinical outcomes. However, the detailed function of DNA hypermethylation in ccRCC has not been fully uncovered. Here, we show the role of DNA methylation in ccRCC progression through the identification of a target(s) of DNA methyltransferases (DNMT). Our preclinical model of ccRCC using the serial orthotopic inoculation model showed the upregulation of DNMT3B in advanced ccRCC. Pretreatment of advanced ccRCC cells with 5-aza-deoxycytidine, a DNMT inhibitor, attenuated the formation of primary tumors through the induction of apoptosis. DNA methylated sites were analyzed genome-wide using methylation array in reference to RNA-sequencing data. The gene encoding ubiquinol cytochrome c reductase hinge protein (UQCRH), one of the components of mitochondrial complex III, was extracted as a methylation target in advanced ccRCC. Immunohistochemical analysis revealed that the expression of UQCRH in human ccRCC tissues was lower than normal adjacent tissues. Silencing of UQCRH attenuated the cytochrome c release in response to apoptotic stimuli and resulted in enhancement of primary tumor formation in vivo, implying the tumor-suppressive role of UQCRH. Moreover, 5-aza-deoxycytidine enhanced the therapeutic efficiency of mammalian target of rapamycin inhibitor everolimus in vivo. These findings suggested that the DNMT3B-induced methylation of UQCRH may contribute to renal cancer progression and implicated clinical significance of DNMT inhibitor as a therapeutic option for ccRCC.

Targeting Epigenetics in Lung Cancer

The epigenetic landscape, which in part includes DNA methylation, chromatin organization, histone modifications, and noncoding RNA regulation, greatly contributes to the heterogeneity that makes developing effective therapies for lung cancer challenging. This review will provide an overview of the epigenetic alterations that have been implicated in all aspects of cancer pathogenesis and progression as well as summarize clinical applications for targeting epigenetics in the treatment of lung cancer.

Cancer epigenetics: Past, present and future

Cancer was thought to be caused solely by genetic mutations in oncogenes and tumor suppressor genes. In the last 35 years, however, epigenetic changes have been increasingly recognized as another primary driver of carcinogenesis and cancer progression. Epigenetic deregulation in cancer often includes mutations and/or aberrant expression of chromatin-modifying enzymes, their associated proteins, and even non-coding RNAs, which can alter chromatin structure and dynamics. This leads to changes in gene expression that ultimately contribute to the emergence and evolution of cancer cells. Studies of the deregulation of chromatin modifiers in cancer cells have reshaped the way we approach cancer and guided the development of novel anticancer therapeutics that target epigenetic factors. There remain, however, a number of unanswered questions in this field that are the focus of present research. Areas of particular interest include the actions of emerging classes of epigenetic regulators of carcinogenesis and the tumor microenvironment, as well as epigenetic tumor heterogeneity. In this review, we discuss past findings on epigenetic mechanisms of cancer, current trends in the field of cancer epigenetics, and the directions of future research that may lead to the identification of new prognostic markers for cancer and the development of more effective anticancer therapeutics.

Studies in lung cancer cytokine proteomics: a review

INTRODUCTION

Proteins are molecules that have role in the progression of the diseases. Proteomics is a tool that can play an effective role in identifying diagnostic and therapeutic biomarkers for lung cancer. Cytokines are proteins that play a decisive role in activating body's immune system in lung cancer. They can increase the growth of the tumor (oncogenic cytokines) or limit tumor growth (anti-tumor cytokines) by regulating related signaling pathways such as proliferation, growth, metastasis, and apoptosis.

AREAS COVERED

In the present study, a total of 223 papers including 196 research papers and 27 review papers, extracted from PubMed and Scopus and published from 1997 to present, are reviewed. The most important involved-cytokines in lung cancer including TNF-α, IFN- γ, TGF-β, VEGF and interleukins such as IL-6, IL-17, IL-8, IL-10, IL-22, IL-1β and IL-18 are introduced. Also, the pathological and biological role of such cytokines in cancer signaling pathways is explained.

EXPERT OPINION

In lung cancer, the cytokine expression changes under the physiological conditions of the immune system, and inflammatory cytokines are associated with the progression of lung cancer. Therefore, the cytokine expression profile can be used in the diagnosis, prognosis, prediction of therapeutic responses, and survival of patients with lung cancer.

Whole-organ analysis of TGF-β-mediated remodelling of the tumour microenvironment by tissue clearing

Tissue clearing is one of the most powerful strategies for a comprehensive analysis of disease progression. Here, we established an integrated pipeline that combines tissue clearing, 3D imaging, and machine learning and applied to a mouse tumour model of experimental lung metastasis using human lung adenocarcinoma A549 cells. This pipeline provided the spatial information of the tumour microenvironment. We further explored the role of transforming growth factor-β (TGF-β) in cancer metastasis. TGF-β-stimulated cancer cells enhanced metastatic colonization of unstimulated-cancer cells in vivo when both cells were mixed. RNA-sequencing analysis showed that expression of the genes related to coagulation and inflammation were up-regulated in TGF-β-stimulated cancer cells. Further, whole-organ analysis revealed accumulation of platelets or macrophages with TGF-β-stimulated cancer cells, suggesting that TGF-β might promote remodelling of the tumour microenvironment, enhancing the colonization of cancer cells. Hence, our integrated pipeline for 3D profiling will help the understanding of the tumour microenvironment.

Neurotensin receptor 1 signaling promotes pancreatic cancer progression

Pancreatic cancer is one of the cancers with the poorest prognosis, with a 5-year survival rate of approximately 5-10%. Thus, it is urgent to identify molecular targets for the treatment of pancreatic cancer. Using serial transplantations in a mouse pancreatic orthotopic inoculation model, we previously produced highly malignant pancreatic cancer sublines with increased tumor-forming abilities in vivo. Here, we used these sublines to screen molecular targets for the treatment of pancreatic cancer. Among the genes with increased expression levels in the sublines, we focused on those encoding cell surface receptors that may be involved in the interactions between cancer cells and the tumor microenvironment. Based on our previous RNA-sequence analysis, we found increased expression levels of neurotensin (NTS) receptor 1 (NTSR1) in highly malignant pancreatic cancer sublines. Furthermore, re-analysis of clinical databases revealed that the expression level of NTSR1 was increased in advanced pancreatic cancer and that high NTSR1 levels were correlated with a poor prognosis. Overexpression of NTSR1 in human pancreatic cancer cells Panc-1 and SUIT-2 accelerated their tumorigenic and metastatic abilities in vivo. In addition, RNA-sequence analysis showed that MAPK and NF-κB signaling pathways were activated upon NTS stimulation in highly malignant cancer sublines and also revealed many new target genes for NTS in pancreatic cancer cells. NTS stimulation increased the expression of MMP-9 and other pro-inflammatory cytokines and chemokines in pancreatic cancer cells. Moreover, the treatment with SR48692, a selective NTSR1 antagonist, suppressed the activation of the MAPK and NF-κB signaling pathways and induction of target genes in pancreatic cancer cells in vitro, while the administration of SR48692 attenuated the tumorigenicity of pancreatic cancer cells in vivo. These findings suggest that NTSR1 may be a prognostic marker and a molecular target for pancreatic cancer treatment.

YAP/TAZ and EZH2 synergize to impair tumor suppressor activity of TGFBR2 in non-small cell lung cancer

Lung cancer is the leading cause of cancer-related deaths, worldwide. Non-small cell lung cancer (NSCLC) is the most prevalent lung cancer subtype. YAP and TAZ have been implicated in lung cancer by acting as transcriptional co-activators of oncogenes or as transcriptional co-repressors of tumor suppressor genes. Previously we reported that YAP and TAZ regulate microRNAs expression in NSCLC. Among the set of regulated miRNAs, the oncogenic miR-25, 93, and 106b, clustering within the MCM7 gene were selected for further studies. We firstly identified Transforming Growth Factor-β (TGF-β) Receptor 2 (TGFBR2), a member of the TGF-β signaling, as a target of the miRNA cluster, which exhibited prognostic value because of its tumor suppressor activity. We found that YAP/TAZ-mediated repression of TGFBR2 occurs both: post-transcriptionally through the miR-106b-25 cluster and transcriptionally by engaging the EZH2 epigenetic repressor that we reported here as a novel target gene of YAP/TAZ. Furthermore, we document that YAP/TAZ and EZH2 cooperate in lung tumorigenesis by transcriptionally repressing a specific subset of tumor suppressor genes, including TGFBR2. Our findings point to YAP/TAZ and EZH2 as potential therapeutic targets for NSCLC treatment.

Inhibition of EZH2 via the STAT3/HOTAIR signalling axis contributes to cell cycle arrest and apoptosis induced by polyphyllin I in human non-small cell lung cancer cells

OBJECTIVE

To explore the potential mechanism of polyphyllin I (PPI)-induced apoptosis in lung cancer cells.

METHODS AND MATERIALS

The pathological changes in lung cancer tissues and paracancerous tissues were first analysed by H&E staining and IHC staining. After PPI treatment, cell viability and apoptosis were detected by MTT assays, cell cycle analyses and flow cytometry. The expression levels of EZH2 and apoptosis-related molecules were evaluated by qRT-PCR and Western blotting.

RESULTS

EZH2 overexpression decreased proapoptotic proteins, and this effect was reversed by PPI. Knockdown of HOTAIR downregulated EZH2 expression, upregulated proapoptotic proteins, and enhanced the effect of PPI treatment. Moreover, knockdown of STAT3 could counteract the effect of HOTAIR overexpression, which significantly increased the expression of EZH2, thus facilitating cell apoptosis in lung cancer.

CONCLUSIONS

PPI induced cell cycle arrest and apoptosis in lung cancer by inhibiting EZH2 through the STAT3/HOTAIR signalling pathway.

Epigenetic landscape of small cell lung cancer: small image of a giant recalcitrant disease

Small cell lung cancer (SCLC) is a particular subtype of lung cancer with high mortality. Recent advances in understanding SCLC genomics and breakthroughs of immunotherapy have substantially expanded existing knowledge and treatment modalities. However, challenges associated with SCLC remain enigmatic and elusive. Most of the conventional drug discovery approaches targeting altered signaling pathways in SCLC end up in the 'grave-yard of drug discovery', which mandates exploring novel approaches beyond inhibiting cell signaling pathways. Epigenetic modifications have long been documented as the key contributors to the tumorigenesis of almost all types of cancer, including SCLC. The last decade witnessed an exponential increase in our understanding of epigenetic modifications for SCLC. The present review highlights the central role of epigenetic regulations in acquiring neoplastic phenotype, metastasis, aggressiveness, resistance to chemotherapy, and immunotherapeutic approaches of SCLC. Different types of epigenetic modifications (DNA/histone methylation or acetylation) that can serve as predictive biomarkers for prognostication, treatment stratification, neuroendocrine lineage determination, and development of potential SCLC therapies are also discussed. We also review the utility of epigenetic targets/epidrugs in combination with first-line chemotherapy and immunotherapy that are currently under investigation in preclinical and clinical studies. Altogether, the information presents the inclusive landscape of SCLC epigenetics and epidrugs that will help to improve SCLC outcomes.