Aggressive Small Cell Lung Cancer Research Articles

Slit2/Robo1 signaling inhibits small-cell lung cancer by targeting β-catenin signaling in tumor cells and macrophages.

Small-cell lung cancer (SCLC) is an aggressive neuroendocrine subtype of lung cancer with poor patient prognosis. However, the mechanisms that regulate SCLC progression and metastasis remain undefined. Here, we show that the expression of the slit guidance ligand 2 (SLIT2) tumor suppressor gene is reduced in SCLC tumors relative to adjacent normal tissue. In addition, the expression of the SLIT2 receptor, roundabout guidance receptor 1 (ROBO1), is upregulated. We find a positive association between SLIT2 expression and the Yes1 associated transcriptional regulator (YAP1)-expressing SCLC subtype (SCLC-Y), which shows a better prognosis. Using genetically engineered SCLC cells, adenovirus gene therapy, and preclinical xenograft models, we show that SLIT2 overexpression or the deletion of ROBO1 restricts tumor growth in vitro and in vivo. Mechanistic studies revealed significant inhibition of myeloid-derived suppressor cells (MDSCs) and M2-like tumor-associated macrophages (TAMs) in the SCLC tumors. In addition, SLIT2 enhances M1-like and phagocytic macrophages. Molecular analysis showed that ROBO1 knockout or SLIT2 overexpression suppresses the transforming growth factor beta 1 (TGF-β1)/β-catenin signaling pathway in both tumor cells and macrophages. Overall, we find that SLIT2 and ROBO1 have contrasting effects on SCLC tumors. SLIT2 suppresses, whereas ROBO1 promotes, SCLC growth by regulating the Tgf-β1/glycogen synthase kinase-3 beta (GSK3)/β-catenin signaling pathway in tumor cells and TAMs. These studies indicate that SLIT2 could be used as a novel therapeutic agent against aggressive SCLC.

A novel combination for the treatment of small cell lung cancer: Active targeted irinotecan and stattic co-loaded PLGA nanoparticles

Polymeric nanoparticles are widely used drug delivery systems for cancer treatment due to their properties such as ease of passing through biological membranes, opportunity to modify drug release, specifically targeting drugs to diseased areas, and potential of reducing side effects. Here, we formulated irinotecan and Stattic co-loaded PLGA nanoparticles targeted to small cell lung cancer. Nanoparticles were successfully conjugated with CD56 antibody with a conjugation efficiency of 84.39 ± 1.01%, and characterization of formulated nanoparticles was conducted with in-vitro and in-vivo studies. Formulated particles had sizes in the range of 130–180 nm with PDI values smaller than 0.3. Encapsulation and active targeting of irinotecan and Stattic resulted in increased cytotoxicity and anti-cancer efficiency in-vitro. Furthermore, it was shown with ex-vivo biodistribution studies that conjugated nanoparticles were successfully targeted to CD56-expressing SCLC cells and distributed mainly to tumor tissue and lungs. Compliant with our hypothesis and literature, the STAT3 pathway was successfully inhibited with Stattic solution and Stattic loaded nanoparticles. Additionally, intravenous injection of conjugated co-loaded nanoparticles resulted in decreased side effects and better anti-tumor activity than individual solutions of drugs in SCLC tumor-bearing mice. These results may indicate a new treatment option for clinically aggressive small cell lung cancer.

Adjuvant therapy for lung neuroendocrine neoplasms.

Pulmonary neuroendocrine neoplasms (NENs) represent a minority of lung cancers and vary from slower growing pulmonary carcinoid (PC) tumors to aggressive small cell lung cancer (SCLC). While SCLC can account for up to 15% of lung cancer, PCs are uncommon and represent about 2% of lung cancers. Surgical resection is the standard of care for early-stage PCs and should also be considered in early stage large cell neuroendocrine carcinoma (LCNEC) and SCLC. Adjuvant treatment is generally accepted for aggressive LCNEC and SCLC, however, less well established for PCs. Guidelines admit a lack of trials to support a high-level recommendation for adjuvant therapy. This manuscript will discuss the role for adjuvant therapy in NENs and review the available literature.

Urothelial Cancers with Small Cell Variant Histology Have Confirmed High Tumor Mutational Burden, Frequent TP53 and RB Mutations, and a Unique Gene Expression Profile

Although predominantly urothelial, some bladder cancer and upper tract urothelial cancer (BC/UTUC) harbor histologic variants. Small cell BC (SCBC) variants comprised ˜5% of The Cancer Genome Atlas BC cohort, with a poor prognosis. We describe genomic profiles of BC/UTUC with small cell/neuroendocrine features identified in the Foundation Medicine database from June 2012 to September 2018. Of 3368 BC/UTUC samples, 3.92% (132) harbored small cell/neuroendocrine features by immunohistochemistry. Mutations were noted in: TP53 (92%), RB1 (75%), combined TP53/RB1 (72%), and TERT promoter (68%). Of the samples, 6.5% had TMB ≥ 10 mutations/Mb. RNA expression profiling of 24 pure SCBC and 51 urothelial BC (UBC) muscle-invasive samples evaluated from a separate cohort revealed a large number of differentially expressed genes with suppression of several inflammatory pathways in SCBC compared with UBC. This largest reported SCBC dataset to date confirms enrichment of signatures in SCBC similar to small cell lung cancer and describes unique gene expression compared with UBC. These findings may explain aggressive SCBC phenotype. Patient summarySmall cell bladder cancer (SCBC) is an aggressive subtype that microscopically resembles aggressive small cell lung cancer (SCLC). This study confirms that SCBC shares DNA changes similar to SCLC and that SCBC expresses many genes that urothelial bladder cancer does not, possibly explaining aggressive SCBC activity.

Prognostic value of post treatment PET scan in small cell lung cancer.

e20013 Background: In most lymphomas, improving patient outcome rely on an assessment of response to therapy. Functional imaging with 18-fluoro-deoxyglucose (FDG) positron emission tomography (PET) increases sensitivity and specificity of disease assessment, predicts outcome and directs future therapies. Lately, PET-scan is more utilized in small cell lung cancer (SCLC) both for initial staging and to assess response to therapy. However, limited data in the literature have evaluated the prognostic value of post-therapy response on PET-scan in SCLC. Methods: This is a retrospective chart-review of SCLC patients who received their first-line chemotherapy between January-2007 and December-2013. Inclusion criteria included complete data on age, sex, race, cancer stage, histologic grade, chemotherapy, radiotherapy, and PET images pre- and post-therapy. CR was defined as either 100% drop in FDG uptake on post-therapy PET-scan. Results: Fifty patients met the inclusion criteria, and served as the basis for this study. 46% had Limited Stage Small Cell Lung Cancer (LS-SCLC), and 54% had Extensive stage small cell lung cancer (ES-SCLC). All were treated with platinum-based chemotherapy in addition to concurrently radiation therapy for the LS-SCLC group. Eleven patients out of the whole cohort achieved CR. Using COX regression model, we evaluated the correlation between achieving CR on post-therapy PET-scan and survival outcome. We found that achieving CR was significantly correlated with worse outcome in ES-SCLC group (HR = 2.70; 95%CI: 1.26-5.81; p = 0.01). While, in the whole cohort and LS-SCLC group, P-value was not statistically significant, nevertheless achieving CR indicated unfavorable outcome (HR = 1.18; 95%CI: 0.51-2.69; p = 0.49) and (HR = 1.99; 95%CI: 0.77-5.13; p = 0.15) respectively. Conclusions: Unlike lymphomas, achieving CR on post-therapy PET-scan in SCLC was associated with worse survival outcome. This might indicate that in aggressive small cell lung cancer, despite excellent response to first-line therapy, the prognosis is still dismal. These results suggest that further prospective studies are warranted to identify the prognostic rule of post-therapy PET-scan in SCLC patients particularly those with ES-SCLC.

99mTc-octreotide receptor scintigraphy in NCI-H446 small cell lung cancer nude mice model

背景与目的小细胞肺癌恶性程度高，早期诊断对其预后有重要价值，目前的检查方法比较局限，传统影像学方法特异性差，而PET/CT价格昂贵，难于推广应用。小细胞肺癌属神经内分泌肿瘤，高表达生长抑素受体，是其早期进行分子影像诊断的理论基石。本实验旨在观察99mTc-octreotide在正常裸鼠体内的分布、代谢及荷人NCI-H446小细胞肺癌裸鼠模型体内显像变化，为临床小细胞肺癌早期诊断奠定基础。方法建立人小细胞肺癌的裸鼠肿瘤模型，正常裸鼠及荷瘤鼠静脉注射99mTc-octreotide显像剂后行动态及延迟显像。运用感兴趣区（region of interest, ROI）技术勾画各时相裸鼠各脏器、肿瘤（T）及肿瘤对侧对应部位（N）放射性计数，计算相应T/N比值，并建立30 min内各ROI的时间-放射性（A-T）曲线。结果① 正常裸鼠的肾脏、肝脏内99mTc-octreotide分布最多，肺部、心脏部位分布较低，头部放射性分布最少，99mTc-octreotide主要通过泌尿系统排泄；各脏器30 min内A-T曲线显示放射性分布随时间延迟呈逐渐下降趋势。②5例荷瘤裸鼠的肿瘤显像均呈阳性；静脉注射99mTc-octreotide后肿瘤部位在3 h显像最清楚，整个检查时间内肝脏放射性强度明显高于肿瘤组织，肺部放射性与肿瘤部位较相近。半定量分析结果显示，静脉注射99mTc-octreotide后肿瘤组织与对侧肢体肌肉的T/N比值在0.5 h、2 h、3 h、4 h分别为1.163±0.03、2.08±0.12、3.03±0.23、2.689±0.31；各时相T/N比值差异有统计学意义（F=51.69, P < 0.000, 1）；通过两两比较发现，静脉注射显像剂后3 h的T/N比值与其他各时相差异均有统计学意义（P < 0.05）；不同检查时间肝脏部位的放射性平均计数高于肿瘤部位，肺部的平均计数与肿瘤相近。肿瘤部位A-T曲线显示，注射99mTc-octreotide后2 min-3 min出现一过性放射性分布高峰。结论运用99mTc-octreotide作显像剂，人小细胞肺癌NCI-H446裸鼠模型具有极高的显像阳性率，且3 h肿瘤显像最清楚。

Abstract 1468: Circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) from patients with small cell lung cancer (SCLC) show heterogeneity in epithelial to mesenchymal transition (EMT) phenotype and evidence of vasculogenic mimicry (VM).

Abstract Background: Circulating tumour cells (CTCs) and circulating tumour microemboli (CTM) are prevalent in patients with aggressive small cell lung cancer (SCLC). Heterogeneity in epithelial and mesenchymal phenotypes in CTCs and within CTM was investigated given evidence in preclinical models of epithelial and mesenchymal cell co-operativity advantageous for hematogenous spread and the role of epithelial to mesenchymal transition (EMT) in invasion and metastasis. Methods: Four colour immunofluorescence assays were developed and applied to tumour cells enriched by filtration from peripheral blood of extensive stage SCLC patients prior to treatment. CTCs/CTM were assessed for expression of cytokeratins (CKs, epithelial marker) and vimentin (mesenchymal marker) with DAPI stained nuclei and negative selection of leukocytes and circulating endothelial cells (CECs) by CD45 and/or vascular endothelial-cadherin (VE-cadherin, CD144) expression respectively. Results and Conclusions: CTCs were identified in all patients that expressed epithelial and/or mesenchymal markers. Individual CTM were detected comprised of tumour cells of heterogeneous EMT status and CTM were also observed containing leukocytes and/or CECs. There was substantial heterogeneity in CK and vimentin expression in CTCs and within CTM consistent with EMT plasticity and with co-operativity between epithelial and mesenchymal tumour cells. A subpopulation of CTCs co-expressed CKs and VE-cadherin that intriguingly, raises the possibility that vascular mimicry accompanies and may facilitate hematogenous spread in this aggressive tumor type. Further studies are required to explore this new hypothesis. Citation Format: Robert Metcalf, Jessica Booth, Rajeeb Swain, Steven Bagley, Karen Morris, Matthew Krebs, Andrew Hughes, Gerard Brady, Fiona Blackhall, Caroline Dive. Circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) from patients with small cell lung cancer (SCLC) show heterogeneity in epithelial to mesenchymal transition (EMT) phenotype and evidence of vasculogenic mimicry (VM). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1468. doi:10.1158/1538-7445.AM2013-1468

Abstract IA10: Pathology of lung neuroendocrine tumors: In search of evidence for classification

Abstract Neuroendocrine (NE) tumors comprise approximately 25% of all tumors in human lung. As a group they continue to provide challenges at biological, molecular and pathological level for uniform classification. The prototype of NE tumors is the highly aggressive small cell lung cancer (SCLC) that accounts 15% of human lung cancers. For years lung cancers were clinically classified mainly into SCLCs and non-SCLCs (NSCLCs) while it has become evident that lung NE tumors actually form a complex spectrum from SCLC to carcinoid with shifting boundaries. The current WHO classification recognizes SCLC, its variant form combined SCLC, typical and atypical carcinoids as well as large cell NE carcinoma (LCNEC) and its variant form combined large cell carcinoma, the last two cancers under the main NSCLC category of large cell carcinoma. With the exception of the LCNEC, it is expected that the diagnoses will be rendered by routine hematoxylin-eosin stain according the established criteria. Benign entities include diffuse idiopathic pulmonary NE cell hyperplasia which is described in the chapter of preinvasive lesions. Over time there have been several efforts to place lung NE tumors into two to four-tier categories according to their malignant potential (high versus low grade) or degree of differentiation often leaving behind confusing terminology that is later misused. Unlike surgically resected NSCLCs, most NE tumors are frequently diagnosed from biopsies which remains a seldom recognized fact that may create its own biases. The diagnosis that experts most often agree with is SCLC, while distinctions between atypical carcinoid and LCNEC that are in the middle of the spectrum are often disputed. Many molecular studies have also “correctly” classified the endpoints of the NE spectrum while grouping in the middle of it has produced varied results. Moreover, several studies have suggested that NSCLCs with NE features (NSCLC-NEs) is a distinct carcinoma type with worse prognosis than ordinary non-NE NSCLC, while others disagree. Biologically this category is very interesting as NSCLCs and SCLCs are ultimately thought to be derived from the same cell. The regulation of NE differentiation is poorly understood. The proneural achaete-scute homolog 1 (ASCL1), a lineage-dependent oncogene may be a key factor for NE differentiation. On the other hand, it was recently shown that the deletion of the tumor suppressor genes Rb1 and p53 specifically in NE cells, a subpopulation of cells in normal airways, or in alveolar non-NE type2 pneumocytes of mice resulted in SCLCs closely mimicking human disease. These results provide experimental evidence for the close relationship of NE and non-NE epithelial cells in carcinogenesis.

6-(7-Nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol, a specific glutathione S-transferase inhibitor, overcomes the multidrug resistance (MDR)-associated protein 1–mediated MDR in small cell lung cancer

In the present work, we have investigated the antitumor activity of 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX) on aggressive small cell lung cancer. NBDHEX not only is cytotoxic toward the parental small cell lung cancer H69 cell line (LC(50) of 2.3 +/- 0.6 micromol/L) but also overcomes the multidrug resistance of its variant, H69AR, which overexpresses the ATP-binding cassette transporter multidrug resistance-associated protein 1 (MRP1; LC(50) of 4.5 +/- 0.9 micromol/L). Drug efflux experiments, done in the presence of a specific inhibitor of MRP1, confirmed that NBDHEX is not a substrate for this export pump. Interestingly, NBDHEX triggers two different types of cell death: a caspase-dependent apoptosis in the H69AR cells and a necrotic phenotype in the parental H69 cells. The apoptotic pathway triggered by NBDHEX in H69AR cells is associated with c-Jun NH(2)-terminal kinase and c-Jun activation, whereas glutathione oxidation and activation of p38(MAPK) is observed in the NBDHEX-treated H69 cells. In contrast to the parental cells, the higher propensity to die through apoptosis of the H69AR cell line may be related to the lower expression of the antiapoptotic protein Bcl-2. Therefore, down-regulation of a factor crucial for cell survival makes H69AR cells more sensitive to the cytotoxic action of NBDHEX, which is not a MRP1 substrate. We have previously shown that NBDHEX is cytotoxic toward P-glycoprotein-overexpressing tumor cell lines. Therefore, NBDHEX seems a very promising compound in the search for new molecules able to overcome the ATP-binding cassette family of proteins, one of the major mechanisms of multidrug resistance in cancer cells.

Multidisciplinary management of lung cancer.

Despite years of research, the five-year survival rate among patients with lung cancer is a mere 14 percent. Lung cancer is divided into two major types — non–small-cell lung cancer and the more aggressive small-cell lung cancer. This review considers the treatment of each type in the framework of multidisciplinary management and recent clinical trials.