Correlation between histone acetylation and expression of Notch1 in human lung carcinoma and its possible role in combined small-cell lung carcinoma

Molecular pathology of small cell lung cancer: Overview from studies on neuroendocrine differentiation regulated by ASCL1 and Notch signaling

Pulmonary neuroendocrine (NE) cells are rare airway epithelial cells. The balance between Achaete-scute complex homolog 1 (ASCL1) and hairy and enhancer of split 1, one of the target molecules of the Notch signaling pathway, is crucial for NE differentiation. Small cell lung cancer (SCLC) is a highly aggressive lung tumor, characterized by rapid cell proliferation, a high metastatic potential, and the acquisition of resistance to treatment. The subtypes of SCLC are defined by the expression status of NE cell-lineage transcription factors, such as ASCL1, which roles are supported by SRY-box 2, insulinoma-associated protein 1, NK2 homeobox 1, and wingless-related integration site signaling. This network reinforces NE differentiation and may induce the characteristic morphology and chemosensitivity of SCLC. Notch signaling mediates cell-fate decisions, resulting in an NE to non-NE fate switch. The suppression of NE differentiation may change the histological type of SCLC to a non-SCLC morphology. In SCLC with NE differentiation, Notch signaling is typically inactive and genetically or epigenetically regulated. However, Notch signaling may be activated after chemotherapy, and, in concert with Yes-associated protein signaling and RE1-silencing transcription factor, suppresses NE differentiation, producing intratumor heterogeneity and chemoresistance. Accumulated information on the molecular mechanisms of SCLC will contribute to further advances in the control of this recalcitrant cancer.

Targeting the Notch signaling pathway and the Notch ligand, DLL3, in small cell lung cancer

Small cell lung cancer (SCLC) is a highly aggressive and poorly differentiated cancer with high-grade neuroendocrine (NE) features, accounting for approximately 15 % of all lung cancers. For decades, chemotherapy and radiotherapy have predominated the treatment strategy for SCLC, but relapses ensue quickly and result in poor survival of patients. Immunotherapy has brought novel insights, yet the efficacy is still restricted to a limited population with SCLC. Notch signaling is identified to play a key role in the initiation and development of SCLC, and the Notch ligand, Delta-like ligand 3 (DLL3) is found broadly and specifically expressed in SCLC cells. Thus, Notch signaling is under active exploration as a potential therapeutic target in SCLC. Herein, we summarized and updated the functional relevance of Notch signaling in SCLC, discussed Notch signaling-targeted therapy for SCLC and the correspondent preclinical and clinical trials, and investigated the promising synergy effects of Notch signaling targeted therapy and immune checkpoint inhibitors (ICIs) treatment.

H3K27 acetylation activated-CCS regulates autophagy and apoptosis of lung cancer by alleviating oxidative stress

Copper chaperone for superoxide dismutase (CCS) is abnormally expressed in various human malignancies. However, the function and mechanism of CCS in lung cancer progression remain unclear. In the current study, CCS protein and mRNA levels were found to be increased in lung adenocarcinoma (LUAD) tissue and cell lines. Patients with higher CCS levels had a poorer prognosis. Decreasing the enrichment of histone H3 Lys27 acetylation (H3K27ac) by A-485 inhibited CCS expression. CCS depletion upregulated reactive oxygen species (ROS) levels, aggravated oxidative stress, inhibited autophagy, inhibited cell survival, and promoted apoptosis. The treatment of antioxidant N-Acetyl-L-cysteine (NAC) rescued these changes induced by CCS depletion. CCS also was found to be related to the immune infiltration of CD8 + T cells and regulatory T cells in LUAD. These data indicated that overexpression of CCS activated by H3K27 acetylation relieved oxidative stress, promoted autophagy, and inhibited apoptosis. CCS may be regarded as a potential therapeutic target for LUAD.

Comprehensive genetic analysis of histological components of combined small cell carcinoma

Background

Combined small‐cell lung cancer (cSCLC) is a rare type of small‐cell lung cancer (SCLC) that includes both SCLC and non‐small‐cell lung cancer (NSCLC). The molecular biological mechanisms underlying the heterogeneity of histological types in combined or metachronously transformed SCLC (mtSCLC) remain unclear. This study aimed to investigate the relationship between genetic alterations and each histological component heterogeneously detected in cSCLC and mtSCLC.

Methods

This study included four cSCLC cases and one mtSCLC case. Formalin‐fixed and paraffin‐embedded sections of each histological component of these tumors were subjected to next‐generation sequencing (NGS) and quantitative reverse transcription‐polymerase chain reaction to investigate the genetic mutations and expression levels of neuroendocrine cell‐specific transcription factors (achaete‐scute homolog‐1 [ASCL1], brain‐2 [BRN2] also known as POU domain class 3 transcription factor 2, nuclear factor 1 B [NF1B], insulinoma‐associated protein 1 [INSM1], and thyroid transcription factor‐1 [TTF‐1]).

Results

NGS analysis revealed that SCLC and NSCLC components share the same somatic mutations detected most frequently in TP53, and also in RB1 and EGFR. Gene expression analysis showed ASCL1 expression was significantly lower in the NSCLC component than in the SCLC component.

Conclusion

We conclude that the morphological evolution of heterogeneous histological components in cSCLC may be associated with differences in ASCL1 expression levels, but not in acquired somatic gene mutations.

Signal pathways and precision therapy of small-cell lung cancer

Small-cell lung cancer (SCLC) encounters up 15% of all lung cancers, and is characterized by a high rate of proliferation, a tendency for early metastasis and generally poor prognosis. Most of the patients present with distant metastatic disease at the time of clinical diagnosis, and only one-third are eligible for potentially curative treatment. Recently, investigations into the genomic make-up of SCLC show extensive chromosomal rearrangements, high mutational burden and loss-of-function mutations of several tumor suppressor genes. Although the clinical development of new treatments for SCLC has been limited in recent years, a better understanding of oncogenic driver alterations has found potential novel targets that might be suitable for therapeutic approaches. Currently, there are six types of potential treatable signaling pathways in SCLC, including signaling pathways targeting the cell cycle and DNA repair, tumor development, cell metabolism, epigenetic regulation, tumor immunity and angiogenesis. At this point, however, there is still a lack of understanding of their role in SCLC tumor biology and the promotion of cancer growth. Importantly optimizing drug targets, improving drug pharmacology, and identifying potential biomarkers are the main focus and further efforts are required to recognize patients who benefit most from novel therapies in development. This review will focus on the current learning on the signaling pathways, the status of immunotherapy, and targeted therapy in SCLC.

Whole-Process Treatment of Combined Small Cell Lung Cancer Initially Diagnosed as "Lung Squamous Cell Carcinoma": A Case Report and Review of the Literature

The rarity and complexity of histology lead to the low diagnosis rate and high misdiagnosis rate of combined small cell lung cancer (C-SCLC). Nowadays, C-SCLC has no commonly recommended therapeutic regimen, mainly conforming to SCLC treatment. Here, we report a patient initially diagnosed as IIIA "lung squamous cell carcinoma" by a small specimen. Radical resection was achieved after neoadjuvant immunochemotherapy, and the final surgical pathology was C-SCLC containing three different histological components. Moreover, in the literature review, we explored the therapeutic effect of neoadjuvant immunotherapy in C-SCLC, expounded the therapeutic conflicts among heterogeneous components, and analyzed the pathology complexity at the tissue, cell, and molecule levels in-depth, including possible genetic characteristics, origin, and evolution by next-generation sequencing (NGS).

In-depth molecular analysis of combined and co-primary pulmonary large cell neuroendocrine carcinoma and adenocarcinoma

Up to 14% of large cell neuroendocrine carcinomas (LCNECs) are diagnosed in continuity with nonsmall cell lung carcinoma. In addition to these combined lesions, 1% to 7% of lung tumors present as co-primary tumors with multiple synchronous lesions. We evaluated molecular and clinicopathological characteristics of combined and co-primary LCNEC-adenocarcinoma (ADC) tumors. Ten patients with LCNEC-ADC (combined) and five patients with multiple synchronous ipsilateral LCNEC and ADC tumors (co-primary) were included. DNA was isolated from distinct tumor parts, and 65 cancer genes were analyzed by next generation sequencing. Immunohistochemistry was performed including neuroendocrine markers, pRb, Ascl1 and Rest. Pure ADC (N = 37) and LCNEC (N = 17) cases were used for reference. At least 1 shared mutation, indicating tumor clonality, was found in LCNEC- and ADC-parts of 10/10 combined tumors but only in 1/5 co-primary tumors. A range of identical mutations was observed in both parts of combined tumors: 8/10 contained ADC-related (EGFR/KRAS/STK11 and/or KEAP1), 4/10 RB1 and 9/10 TP53 mutations. Loss of pRb IHC was observed in 6/10 LCNEC- and 4/10 ADC-parts. The number and intensity of expression of Ascl1 and neuroendocrine markers increased from pure ADC (low) to combined ADC (intermediate) and combined and pure LCNEC (high). The opposite was true for Rest expression. In conclusion, all combined LCNEC-ADC tumors were clonally related indicating a common origin. A relatively high frequency of pRb inactivation was observed in both LCNEC- and ADC-parts, suggesting an underlying role in LCNEC-ADC development. Furthermore, neuroendocrine differentiation might be modulated by Ascl1(+) and Rest(-) expression.

NOTCH alteration in EGFR-mutated lung adenocarcinoma leads to histological small-cell carcinoma transformation under EGFR-TKI treatment

BACKGROUND

Molecular targeted therapy has been developed as an innovative treatment for metastatic cancer. Epidermal growth factor receptor (EGFR) mutation is one of the most important and frequent oncogenic drivers in non-small-cell lung cancer, and EGFR-tyrosine kinase inhibitors are indispensable drugs for mutation-positive patients. Currently, the acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is a problem, the mechanism of which has not been elucidated. The histological transformation from original adenocarcinoma to small-cell carcinoma is rare; however, it has been detected in many cases after EGFR-TKI treatment. This study aimed to evaluate mutational status in two different histological types and further elucidate the molecular pathogenesis.

METHODS

Three patients with EGFR-mutant lung cancer who underwent a histological transformation to small-cell carcinoma after growth factor receptor-TKI treatment were enrolled in this study. Two samples per patient were collected from histologically different lesions, and DNA samples were extracted from formalin-fixed, paraffin-embedded tumor tissues. The paired samples were subjected to next-generation sequencing of 160 cancer-related genes. Based on the sequencing results, the expression levels of related proteins were validated using reverse-transferase polymerase chain reaction and immunohistochemical staining.

RESULTS

The following five variants were common among the three cases: MTOR, JAK1, NOTCH2, CSF1R, and MAP2K2. The former four variants were additive to small-cell carcinoma, and the last variant was lost. Both TP53 and Rb1 alterations were detected in adenocarcinoma. Notch2 expression was negative in small-cell carcinoma in both reverse-transcriptase polymerase chain reaction analysis and immunohistochemical staining. ASCL1 expression increased after histological transformation detected using both methods in one case, only these samples were evaluable.

CONCLUSIONS

Notch and ASCL1 signaling are the master regulators of neuroendocrine differentiation in small-cell lung carcinoma. Our results suggest that the Notch-ASCL1 axis may also play an essential role in the transformation of small-cell carcinoma under TP53 and RB1 inactivation.

Small cell lung cancer transformation during antitumor therapies: A systematic review

Lung cancer is the most common cause of cancer-related death. Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are the two major histological categories of lung cancers. Drug resistance is a great challenge for cancer treatment, and histological transformation from NSCLC to SCLC is one of the mechanisms underlying drug resistance in NSCLC patients. SCLC-transformed patients show combined characteristics of NSCLC and SCLC; however, they lack timely diagnoses and effective treatment strategies. Thus, we reviewed the clinical characteristics of SCLC transformation patients with a literature search to enhance clinical consciousness, diagnosis, and personalized treatment for patients with it.

Notch signaling and efficacy of PD-1/PD-L1 blockade in relapsed small cell lung cancer

Immune checkpoint blockade (ICB) benefits only a small subset of patients with small cell lung cancer (SCLC), yet the mechanisms driving benefit are poorly understood. To identify predictors of clinical benefit to ICB, we performed immunogenomic profiling of tumor samples from patients with relapsed SCLC. Tumors of patients who derive clinical benefit from ICB exhibit cytotoxic T-cell infiltration, high expression of antigen processing and presentation machinery (APM) genes, and low neuroendocrine (NE) differentiation. However, elevated Notch signaling, which positively correlates with low NE differentiation, most significantly predicts clinical benefit to ICB. Activation of Notch signaling in a NE human SCLC cell line induces a low NE phenotype, marked by increased expression of APM genes, demonstrating a mechanistic link between Notch activation, low NE differentiation and increased intrinsic tumor immunity. Our findings suggest Notch signaling as a determinant of response to ICB in SCLC.

Immune checkpoint blockade (ICB) benefits only a small subset of patients with small cell lung cancer (SCLC) and the mechanisms driving benefit are poorly understood. Here, the authors show that elevated Notch signaling predicts clinical benefit in ICB in relapsed SCLC.

H3K27 acetylation activated-COL6A1 promotes osteosarcoma lung metastasis by repressing STAT1 and activating pulmonary cancer-associated fibroblasts

Background: Collagen type VI alpha 1 (COL6A1) has been found to be dysregulated in several human malignancies. However, the role of COL6A1 in osteosarcoma (OS) progression remains largely unclear. Here, we aimed to explore the clinical significance and biological involvement of COL6A1 in the OS cell migration and invasion. Material and Methods: We used immunohistochemistry, qRT-PCR and western blot to detect the expression of COL6A1 in 181 OS patient samples. Chromatin immunoprecipitation (ChIP) and PCR were carried out to verify the regulatory interaction of p300, c-Jun and COL6A1 promoter. The invasion and migration function of COL6A1 in OS was detected in vitro and in vivo. RNA sequence was performed to detect the downstream pathway of COL6A1, and then co-immunoprecipitation (co-IP), ubiquitination assays and rescue experiments were performed to determine the regulatory effect of COL6A1 and signal transducers and activators of transcription (STAT1). Exosomes derived from OS cell lines were assessed for the ability to promote cancer progression by co-cultured assay and exosomes tracing. Results: COL6A1 was commonly upregulated in OS tissues, especially in lung metastasis tissues, which was associated with a poor prognosis. c-Jun bound p300 increased the enrichment of H3K27ac at the promoter region of the COL6A1 gene, which resulted in the upregulation of COL6A1 in OS. Overexpression of COL6A1 promoted OS cell migration and invasion via interacting with SOCS5 to suppress STAT1 expression and activation in an ubiquitination and proteasomal degradation manner. Most interestingly, we found that exosomal COL6A1 derived from OS cells convert normal fibroblasts to cancer-associated fibroblasts (CAFs) by secreting pro-inflammatory cytokines, including IL-6 and IL-8. The activated CAFs could promote OS cell invasion and migration by mediating TGF-β/COL6A1 signaling pathway. Conclusion: Our data demonstrated that upregulation of COL6A1 activated by H3K27 acetylation promoted the cell migration and invasion by suppressing STAT1 pathway in OS cells. Moreover, COL6A1 can be packaged into OS cell-derived exosomes and activate CAFs to promote OS metastasis.

Identifying specific Notch1 target proteins in lung carcinoma cells

BACKGROUND

The Notch signaling pathway has different roles in many human neoplasms, being either tumor-promoting or anti-proliferative. In addition, Notch signaling in carcinogenesis can be tissue dependent. The aim of the current study is to elucidate the relation between Notch1 protein expression in lung cancer cells and the following Notch related proteins: Hes1, c-Myc, Jagged1 and Jagged2.

METHODS

Notch1 and its related proteins were detected in human lung cancer cell lines and in 54 surgically resected different lung carcinoma tissues. Then, we used small interfering RNA (siRNA) technology, to down-regulate the expression of Notch1 in H69AR and SBC3 small cell lung carcinoma (SCLC) cells. Also, we transfected venus Notch1 intracellular domain (v.NICD) plasmid into human SCLC lines; H69.

RESULTS

The expression of Hes1, c-Myc and Jagged2 is affected by Notch1 in SCLC.

CONCLUSION

There is a strong association between the expression of Notch1 protein and the expression of Hes1, c-Myc and Jagged2 proteins, which could aid in better understanding tumorigenesis in SCLC.

Clinical characteristics and prognostic factors of surgically resected combined small cell lung cancer: a retrospective study

OBJECTIVES

Small cell lung cancer (SCLC) is the most malignant lung cancer. Some of them are mixed with non-small cell lung cancer(NSCLC, Non SCLC),which are called combined small cell lung cancer (C-SCLC).Due to the difficulty of pathological diagnosis and the complexity of treatment, studies of C-SCLC have just been rising in recent years. This study is to evaluate the clinical and pathologic characteristics of C-SCLC.

METHODS

Stage Ⅰ-Ⅲa C-SCLC patients who received radical R0 surgery between 2009-2018 in Shanghai Chest Hospital were enrolled. Clinical characteristics and prognosis were analyzed.

RESULTS

Totally 181 patients were included, most of them were small cell combined with large cell neuroendocrine components(SCLC/LCNEC,58.0 %,N = 105),then with adenocarcinoma(SCLC/ADC:13.8 %,N = 25),and finally with squamous cell carcinoma(SCLC/SCC:13.3 %,N = 24).Median DFS and OS of C-SCLC patients underwent radical surgery were 32.5 and 49.7 months.1,3 and 5 years DFS rates of the entire cohort were 68.5 %,32.6 % and 16.0 %,respectively. Patients with SCLC/LCNEC had longer DFS (44.1 m vs. 20.4 m, p = 0.040) and longer OS trend (62.1 m vs. 33.2 m, p = 0.122).Groups of whether tumor invaded the pleura(p = 0.028 and p = 0.050),lymph node stage(p = 0.029 and p = 0.010) and the courses of adjuvant chemotherapy(p = 0.011 and p = 0.001) had statistical differences on DFS and OS.

CONCLUSIONS

SCLC/LCNEC was the most common type of C-SCLC. Patients' DFS and OS were also longer than other combined types. Adjuvant chemotherapy for SCLC is still the main treatment for surgical C-SCLC. Further studies are needed to clarify the clinical characteristics and prognosis of C-SCLC.

Notch pathway in small-cell lung cancer: from preclinical evidence to therapeutic challenges

BACKGROUND

Small-cell lung cancer (SCLC) is an aggressive disease with still limited therapeutic options. Despite being both a chemo- and radiation-sensitive malignancy, SCLC recurrence occurs in most cases and negatively impacts patients' prognosis. Over the last few years, a deeper understanding of SCLC molecular aberrations has led to the identification of Notch pathway deregulation as a crucial event in SCLC tumorigenesis, disease progression and chemoresistance. In particular, the delta-like protein 3 (DLL3), a Notch inhibitory ligand whose expression is directly related to the key neuroendocrine transcription factor ASCL1, was found to be expressed in ~85% of SCLCs, while it exhibits minimal to absent surface expression in normal lungs. DLL3 thus represents an appealing novel biomarker as well as a potential target in SCLC.

CONCLUSIONS

The first DLL3-targeted antibody-drug conjugate rovalpituzumab tesirine (Rova-T, SC16LD6.5) has shown promising results in terms of efficacy and safety for the management of extensive SCLC, supporting further studies on this novel therapeutic approach that combines specific SCLC targeting with the cell-killing ability of a pyrrolobenzodiazepine dimer. In the present review, we discuss currently available evidence on the biological role of Notch signaling in SCLC from early preclinical findings to current and future clinical implications.

Combined small-cell lung carcinoma

Currently, studies assessing combined small-cell lung carcinoma (C-SCLC) are relatively scarce and limited. Indeed the clinicopathological features, treatment, and prognosis of patients with C-SCLC have not been fully determined. The incidence of C-SCLC ranges from 5%–28% in different studies, which is related to the specimen types used. The clinical features of C-SCLC are characterized by the higher proportion of peripheral locations, earlier stage, and more opportunity to experience surgery. Surgery is more important for earlier stage C-SCLC. There have been no recent changes in the chemotherapy of C-SCLC, which is recommended by the treatment guidelines for SCLC, neither showing survival benefit from the 3-agent regimen. Meanwhile, the efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in EGFR-mutated C-SCLC patients remains inconclusive. This review focuses on clinical and pathologic features, prognostic factors, and optimized treatment model in C-SCLC.

Association of Smoking, Alcohol Use, and Betel Quid Chewing with Epigenetic Aberrations in Cancers

Numerous environmental factors such as diet, alcohol use, stress, and environmental chemicals are known to elicit epigenetic changes, leading to increased rates of cancers and other diseases. The incidence of head and neck cancer, one of the most common cancers in Taiwanese males, is increasing: oral cancer and nasopharyngeal carcinoma are ranked fourth and tenth respectively, among the top ten cancers in this group, and a major cause of cancer-related deaths in Taiwanese males. Previous studies have identified smoking, alcohol use, and betel quid chewing as the three major causes of head and neck cancers; these three social habits are commonly observed in Taiwanese males, resulting in an increasing morbidity rate of head and neck cancers in this population. In this literature review, we discuss the association between specific components of betel quid, alcohol, and tobacco, and the occurrence of head and neck cancers, lung cancer, gastrointestinal cancers, and urethral cancer. We focus on regulatory mechanisms at the epigenetic level and their oncogenic effects. The review further discusses the application of FDA-approved epigenetic drugs as therapeutic strategies against cancer.