Small Cell Lung Cancer Metastasis Research Articles

Involvement of Epithelial-Mesenchymal Transition Genes in Small Cell Lung Cancer Phenotypic Plasticity.

Small cell lung cancer (SCLC) is an aggressive cancer recalcitrant to treatment, arising predominantly from epithelial pulmonary neuroendocrine (NE) cells. Intratumor heterogeneity plays critical roles in SCLC disease progression, metastasis, and treatment resistance. At least five transcriptional SCLC NE and non-NE cell subtypes were recently defined by gene expression signatures. Transition from NE to non-NE cell states and cooperation between subtypes within a tumor likely contribute to SCLC progression by mechanisms of adaptation to perturbations. Therefore, gene regulatory programs distinguishing SCLC subtypes or promoting transitions are of great interest. Here, we systematically analyze the relationship between SCLC NE/non-NE transition and epithelial to mesenchymal transition (EMT)-a well-studied cellular process contributing to cancer invasiveness and resistance-using multiple transcriptome datasets from SCLC mouse tumor models, human cancer cell lines, and tumor samples. The NE SCLC-A2 subtype maps to the epithelial state. In contrast, SCLC-A and SCLC-N (NE) map to a partial mesenchymal state (M1) that is distinct from the non-NE, partial mesenchymal state (M2). The correspondence between SCLC subtypes and the EMT program paves the way for further work to understand gene regulatory mechanisms of SCLC tumor plasticity with applicability to other cancer types.

Study on the Biological Function of Abemecilib in Inhibiting the Proliferation, Invasion and Migration of Small Cell Lung Cancer with High c-Myc Expression

Small cell lung cancer (SCLC) with high c-Myc expression is prone to relapse and metastasis, leading to extremely low survival rate. Cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitor Abemaciclib plays a key role in the treatment of tumors, but the effects and mechanisms on SCLC remain unclear. This study was to analyze the effect and molecular mechanism of Abemaciclib in inhibiting proliferation, migration and invasion of SCLC with high c-Myc expression, with a view to expanding a new direction for reducing the recurrence and metastasis. Proteins interacting with CDK4/6 were predicted using the STRING database. The expressions of CDK4/6 and c-Myc in 31 cases of SCLC cancer tissues and paired adjacent normal tissues were analyzed by immunohistochemistry. The effects of Abemaciclib on the proliferation, invasion and migration of SCLC were detected by CCK-8, colony formation assay, Transwell and migration assay. Western blot was used to detect the expressions of CDK4/6 and related transcription factors. Flow cytometry was used to analyze the effects of Abemaciclib on the cell cycle and checkpoint of SCLC. The expression of CDK4/6 was associated with c-Myc by STRING protein interaction network. c-Myc can directly modalize achaete-scute complex homolog 1 (ASCL1), neuronal differentiation 1 (NEUROD1) and Yes-associated protein 1 (YAP1). Moreover, CDK4 and c-Myc regulate the expression of programmed cell death ligand 1 (PD-L1). Immunohistochemistry showed that the expressions of CDK4/6 and c-Myc in cancer tissues were higher than those in adjacent tissues(P<0.0001). CCK-8, colony formation assay, Transwell and migration assay verified that Abemaciclib could effectively inhibit the proliferation, invasion and migration of SBC-2 and H446OE(P<0.0001). Western blot analysis further showed that Abemaciclib not only inhibited CDK4 (P<0.05) and CDK6 (P<0.05), but also affected c-Myc (P<0.05), ASCL1 (P<0.05), NEUROD1 (P<0.05) and YAP1 (P<0.05), which are related to SCLC invasion and metastasis. Flow cytometry showed that Abemaciclib not only inhibited the cell cycle progression of SCLC cells (P<0.0001), but also significantly increased PD-L1 expression on SBC-2 (P<0.01) and H446OE (P<0.001). Abemaciclib significantly inhibits the proliferation, invasion, migration and cell cycle progression of SCLC by inhibiting the expressions of CDK4/6, c-Myc, ASCL1, YAP1 and NEUROD1. Abemaciclib can also increase the expression of PD-L1 in SCLC.

Potential Avenues for Exosomal Isolation and Detection Methods to Enhance Small-Cell Lung Cancer Analysis.

Around the world, lung cancer has long been the main factor in cancer-related deaths, with small-cell lung cancer (SCLC) being the deadliest form of lung cancer. Cancer cell-derived exosomes and exosomal miRNAs are considered promising biomarkers for diagnosing and prognosis of various diseases, including SCLC. Due to the rapidity of SCLC metastasis, early detection and diagnosis can offer better diagnosis and prognosis and therefore increase the patient's chances of survival. Over the past several years, many methodologies have been developed for analyzing non-SCLC-derived exosomes. However, minimal advances have been made in SCLC-derived exosome analysis methodologies. This Review discusses the epidemiology and prominent biomarkers of SCLC. Followed by a discussion about the effective strategies for isolating and detecting SCLC-derived exosomes and exosomal miRNA, highlighting the critical challenges and limitations of current methodologies. Finally, an overview is provided detailing future perspectives for exosome-based SCLC research.

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.

The postoperative prognosis of skip-N2 metastasis is favorable in small-cell lung carcinoma patients with pathological N2 classification: a propensity-score-adjusted retrospective multicenter study.

The study on skip-N2 metastasis in small-cell lung cancer (SCLC) is lacking. Therefore, this study aimed to explore the prognostic significance of skip-N2 metastasis based on a multicenter cohort. We collected 176 SCLC patients with pathological categories T1-4N1-2M0 from four hospitals in China. Survival curves were drawn through the Kaplan-Meier method and compared by the log-rank test. The Cox regression method was used to calculate the hazard ratio (HR) and 95% confidence interval of the characteristics for cancer-specific survival (CSS). Two propensity-score methods were used to reduce the bias, including the inverse probability of treatment weighting (IPTW) and propensity-score matching (PSM). This multicenter database included 64 pN1 patients, 63 non-skip-N2 cases, and 49 skip-N2 cases. Skip-N2 and the non-skip-N2 patients had gap CSS rates (skip-N2 no versus yes: 41.0% versus 62.0% for 1-year CSS, 32.0% versus 46.0% for 2-year CSS, and 20.0% versus 32.0% for 3-year CSS). After PSM, there were 32 pairs of patients to compare survival differences between N2 and skip-N2 diseases, and 34 pairs of patients to compare prognostic gaps between N1 and skip-N2 diseases, respectively. The results of IPTW and PSM both suggested that skip-N2 cases had better survival outcomes than the non-skip-N2 cases (IPTW-adjusted HR = 0.578; PSM-adjusted HR = 0.510; all log-rank p < 0.05). Besides, the above two analytic methods showed no difference in prognoses between pN1 and skip-N2 diseases (all log-rank p > 0.05). Skip-N2 patients were confirmed to have a better prognosis than non-skip-N2 patients. Besides, there was no survival difference between pN1 and skip-N2 cases. Therefore, we propose that the next tumor-node-metastasis staging system needs to consider the situation of skip metastasis with lymph nodes in SCLC.

NLRP6 is required for cancer-derived exosome-modified macrophage M2 polarization and promotes metastasis in small cell lung cancer

Metastasis remains the primary cause of small cell lung cancer (SCLC)-related deaths. Growing evidence links tumor metastasis with a pre-metastatic microenvironment characterized by an anti-inflammatory response, immunosuppression, and the presence of tumor-derived exosomes. To clarify the relationships among these factors in SCLC, we analyzed SCLC patient samples as well as a mouse model. Among the infiltrating immune cells, our study focused on the tumor-associated macrophages (TAMs), that are well-known to promote tumor progression and metastasis. We found that high expression of the alternatively activated (M2) TAM marker, CD206+ was associated clinically with a poorer prognosis and metastasis state in patients with SCLC. Moreover, infiltrating macrophages (MØ) were found in the metastatic foci of an SCLC mouse model. Additionally, we observed dominant switching to M2 phenotype, accompanied by increased NLRP6 expression. Since tumor-derived exosomes are the key links between the tumor and its immune microenvironment, we further investigated whether SCLC-derived exosomes contributed to the MØ phenotype switch. Our findings showed for the first time that SCLC-derived exosomes induce the M2 switch via the NLRP6/NF-κB pathway, and thus, promote SCLC metastasis in vitro and in vivo. Collectively, these results indicate a novel mechanism by which SCLC-derived exosomes induce immunosuppression of distant MØ to promote systemic metastasis by activating NLRP6. Here, we highlight the close relationship between the tumor-derived exosomes, inflammasomes and immune microenvironment in SCLC metastasis.

The prognostic risk stratification model for metastatic small-cell lung cancer: An analysis of the SEER database.

Distant metastases of small-cell lung cancer (DM-SCLC) is an important factor in the selection of treatment strategies. In this study, we established a nomogram to predict DM-SCLC and determine the benefit of radiotherapy (RT) for DM-SCLC. We analyzed DM-SCLC prognosis based on surveillance, epidemiology, and end result database (SEER) data. A comprehensive and practical nomogram that predicts the overall survival (OS) of DM-SCLC was constructed and the results were compared with the 7th edition of the American Joint Committee on Cancer (AJCC) TNM stage system. A concordance index (C-index) and receiver operating characteristic plot were generated to evaluate the nomogram discrimination. The calibration was evaluated with a calibration plot, and its effectiveness was evaluated by a decision curve analysis (DCA). A score was assigned to each variable, and a total score was established for the risk stratification model. A total of 13,403 DM-SCLC patients were included. Eight characteristic variables were identified as independent prognostic variables. The C-index of the validation and training cohorts was 0.716 and 0.734, respectively. The area under the receiver operating characteristic curve (AUC) values of the nomogram used to predict 1-, 2-, and 3-year OS were 0.751, 0.744, and 0.786 in the validation cohorts (0.761, 0.777, 0.787 in the training cohorts), respectively. The calibration curve of 1-, 2-, 3-year survival rates showed that the prediction of the nomogram was in good agreement with the actual observation. The nomogram exhibited higher clinical utility after evaluation with the 1-, 2-, 3-year DCA compared with the AJCC stage system. A predictive nomogram and risk stratification model have been constructed to evaluate the prognosis of DM-SCLC effectively and accurately. This nomogram may provide a reference for prognosis stratification and treatment decisions.

The Impact of Chemosensitivity on the Outcome of Brain Metastases in Small-Cell Lung Cancer: A Retrospective Analysis.

Purpose: The purpose of this study was to investigate the prognostic differences between patients with small-cell lung cancer (SCLC) with different chemosensitivity to first-line chemotherapy who developed brain metastasis (BM) as the first site of progression. Methods: Patients with a BM after first-line treatment in the Tianjin Cancer Hospital were retrospectively analyzed. According to the time-free interval (TFI) between the completion of first-line chemotherapy and the onset of the BM, the patients were divided into the chemo-sensitive group (TFI ≥ 90 days, n = 145) and the chemo-resistant group (TFI < 90 days, n = 97). The survival time, which was calculated from the diagnosis of the BM, was analyzed after the onset of brain metastasis (BM-OS). Survival curves were plotted using the Kaplan–Meier method, and differences between groups were compared using the log-rank test. Results: In total, the median BM-OS was 8.4 months. The median BM-OS in the chemo-sensitive group was 8.8 months, and it was 8.0 months in the chemo-resistant group (p = 0.538). In patients without extracranial progression (n = 193), the median BM-OSes in the chemo-sensitive and chemo-resistant groups were 9.4 months and 9.7 months, respectively (p = 0.947). In patients with extracranial progression (n = 49), the median BM-OSes in the chemo-sensitive and chemo-resistant groups were 5.4 months and 4.2 months, respectively (p = 0.161). Conclusions: After the development of a BM as the first site of progression following chemotherapy in patients with SCLC, the prognosis of chemo-sensitive patients was not necessarily superior to chemo-resistant patients, especially in patients without extracranial progression.

S1920 A Rare Case of Small Cell Lung Cancer With Pancreatic Metastasis Presenting as Obstructive Jaundice

Introduction: Small cell lung cancer (SCLC) is an aggressive high grade neuroendocrine carcinoma that accounts for 15% of all lung cancers & usually presents with early distant metastatic spread typically to liver, bone, brain & lung on diagnosis. Pancreas is a very uncommon site of metastasis. We present a rare case of SCLC metastasis to the pancreas presenting as obstructive jaundice upon initial presentation. Case Description/Methods: A 62-year-old male with a past medical history of recurrent pancreatitis presented to the emergency department with abdominal pain, nausea, vomiting, & jaundice. Routine blood work on admission were notable for elevated total bilirubin of 16.4 mg/dL along with elevation in alkaline phosphatase at 547 IU/L & elevation in AST & ALT to 120 U/L & 144 U/L, respectively. Imaging with CT followed by MRI abdomen showed focal enlargement of the pancreatic head with dilatation of the common bile duct & the main pancreatic duct along with innumerable rim-enhancing lesions within the liver consistent with metastasis. CT Chest was also done that showed a large right suprahilar mass with mass effect on the right main bronchus. CT guided biopsy of liver lesion was performed which confirmed small cell carcinoma on pathology. Worsening jaundice prompted ERCP with EUS which showed a large mass at the major papilla site. Pancreatic duct was cannulated & sphincterotomy was performed; However, biliary cannulation could not be completed due to the size of the mass & prior history of chronic pancreatitis cannulation. Patient subsequently underwent IR guided PTC drain placement with appropriate decrease in bilirubin. Chemotherapy was initiated with carboplatin/ etoposide for metastatic small cell cancer with spread to the pancreas & liver (Figure). Discussion: SCLC metastasis to pancreas is rare & majority of patients with pancreatic metastasis are asymptomatic upon incidental diagnosis by abdominal CT. Pancreatitis & obstructive jaundice are seldom found on initial presentation, as seen in our patient. Jaundice can result from biliary ductal obstruction if SCLC spreads to lymph nodes in the porta hepatis or the pancreatic head. Endoscopic ultrasound (EUS) is more sensitive than CT or MRI in the diagnosis of pancreatic malignancy. Metastasis to pancreas typically indicates advanced disease & clinicians should consider palliative treatment with surgical biliary bypass & chemotherapy in select patient groups which has shown to lead to clinically significant increased mean survival time.Figure 1.: MRI Abdomen with contrast transverse image showing rim-enhancing lesions within the liver and focal enlargement of the pancreatic head with dilatation of the common bile duct and the main pancreatic duct (A). Endoscopic imaging showing a large fungating mass was found at the major papilla (B).

Role of apparent diffusion coefficient measurement in differentiating histological subtypes of brain metastasis of lung cancer

SUMMARYOBJECTIVE:The aim of this study was to investigate the role of apparent diffusion coefficient of diffusion-weighted imaging in differentiating histological subtypes of brain metastasis of lung cancer.METHODS:Diffusion-weighted imaging of 158 patients (mean age: 61.2±10.68 years) with brain metastasis of lung cancer (36 small cell lung cancer and 122 non-small cell lung cancer) were retrospectively evaluated. The minimum and mean apparent diffusion coefficient values of the metastasis, apparent diffusion coefficient of edema around the metastasis, and apparent diffusion coefficient of contralateral brain parenchyma were measured. Normalized apparent diffusion coefficient was calculated by proportioning the mean apparent diffusion coefficient of the metastasis to the apparent diffusion coefficient of the contralateral brain parenchyma. Minimum and mean apparent diffusion coefficient of the metastasis, apparent diffusion coefficient of edema around metastasis, and normalized apparent diffusion coefficient were compared between small cell lung cancer and non-small cell lung cancer metastases.RESULTS:Minimum apparent diffusion coefficient, mean apparent diffusion coefficient, and normalized apparent diffusion coefficient values of small cell lung cancer metastases (0.43±0.19×10−3mm2/s, 0.63±0.20×10−3mm2/s, and 0.81 [0.55–1.44], respectively) were significantly lower than those of non-small cell lung cancer metastases (0.71±0.26×10−3mm2/s, 0.93±0.29×10−3mm2/s, and 1.30 [0.60–3.20], respectively; p<0.001). Mean apparent diffusion coefficient of edema of small cell lung cancer metastases (1.21±0.28×10−3mm2/s) was significantly lower than that of non-small cell lung cancer metastases (1.39±0.26×10−3mm2/s, p=0.020). The best cutoff values of minimum apparent diffusion coefficient, mean apparent diffusion coefficient, normalized apparent diffusion coefficient, and apparent diffusion coefficient of edema for the differentiation of small cell lung cancer and non-small cell lung cancer were found to be 0.56×10−3mm2/s, 0.82×10−3mm2/s, 1.085, and 1.21×10−3mm2/s, respectively. The area under the receiver operating characteristic curve, sensitivity, and specificity values were, respectively, 0.812, 80.6, and 73.8% for minimum apparent diffusion coefficient; 0.825, 91.7, and 61.5% for mean apparent diffusion coefficient; 0.845, 80.6, and 73.8% for normalized apparent diffusion coefficient; and 0.698, 75.0, and 67.7% for apparent diffusion coefficient of edema.CONCLUSIONS:Minimum apparent diffusion coefficient, mean apparent diffusion coefficient, normalized apparent diffusion coefficient, and apparent diffusion coefficient of edema around metastasis can differentiate histological subtypes of brain metastasis of lung cancer.

Epigenetic reprogramming in small cell lung cancer

Small cell lung cancer (SCLC), a highly lethal lung cancer sub-type with distinct neuroendocrine-like features, accounts for 10%–15% of all lung cancers. The overall 5-year survival rate remains less than 10%. SCLC is characterized by early metastasis, thus minimizing the potential patient benefits of surgery. In recent decades, the first-line treatment for SCLC has remained chemotherapy combining etoposide and cisplatin (E/P). Despite high rates of response to E/P treatment, SCLC eventually relapses and is almost universally resistant to treatment at recurrence, thus making SCLC a recalcitrant malignancy. Moreover, the limited knowledge regarding the molecular mechanisms underlying SCLC metastasis and resistance greatly hinders improvements in overall SCLC survival. To better understand the molecular mechanisms of SCLC and discover potential therapeutic targets, extensive efforts have continued for decades. Recently, several studies have implicated epigenetic modifications, including histone modifications, DNA methylation, and chromatin accessibility, in SCLC. NFIB has been documented to promote SCLC metastasis through a widespread increase in chromatin accessibility1. Of particular note, one recent study has indicated that KMT2C deficiency promotes SCLC metastasis through DNMT3A-mediated epigenetic reprogramming involving both histone and DNA hypomethylation2. These studies have revealed that epigenetic reprogramming plays an important role in SCLC. In this review, we summarize and discuss the advances in basic and translational research in SCLC, which have revealed the functional and targetable roles of epigenetic modifications during tumorigenesis, metastasis, and chemoresistance.

Automated detection and segmentation of small cell lung cancer liver metastases on CT.

e13555 Background: Small cell lung cancer (SCLC) is a highly malignant cancer that commonly metastasizes throughout the body (mSCLC) and is molecularly classified based on expression of four transcription regulators (NAPY): NeuroD1, ASCL1. POU2F3, and YAP1. Medical imaging is used for treatment monitoring and patient management. Due to the relatively rare occurrence of this disease, large cohorts of data are not available for training. The purpose of this work is to develop a model for automated detection and segmentation of mSCLC liver metastases by leveraging publicly available data and characterize its output against NAPY subtyping. Methods: Two datasets were used: (1) the Liver Tumor Segmentation Challenge (LiTS), a public dataset containing 130 CT scans and (2) 23 patients with mSCLC imaged at our institution with biopsy-confirmed SCLC metastasis to the liver and available NAPY subtyping. N = 12 mSCLC scans underwent ground truth lesion segmentation by an experienced radiologist (&gt; 10yrs) using ITK-Snap. The LiTS dataset was split to 80/12/8 for training/validation/testing. The mSCLC data was reserved for testing. CT scans were resampled to uniform z-spacing of 1mm and Hounsfield range. A liver organ segmentation model based on 2D UNet and liver lesion segmentation model based on DeepLabV3+ were trained using Fast.ai library. Random flipping, rotation, erasing, and variable CT windowing were applied in each batch. Hyperparameters included cross-entropy loss, Adam optimization, batch size 32, input size [512,512], 1e-4 learning rate, 100 epochs, pre-trained weights from ImageNet. The final liver volume was selected as largest 3D-connected component of output and was used as input to lesion segmentation. Segmentation performance was evaluated by Dice Similar Coefficient (DSC). AI-based lesion segmentations were used to extract 106 shape and texture features (PyRadiomics) for association to NAPY subtypes using logistic regression analysis accounting for the clustered nature of lesion data on the patient-level. Results: The liver model achieved median DSC 0.952 (range (0.926-0.964) and 0.958 (range 0.933-0.969) in the LiTs validation and testing sets, respectively. Lesion segmentation results in validation and testing sets achieved median DSC 0.639 (0-0.848) and 0.523 (0-0.878), respectively. This model demonstrated acceptable generalizabilty in the mSCLC patients from our institution with median Dice coefficient 0.696 (0.102-0.882). Overall, the model achieved 62.1% sensitivity and 88.2% PPV with median 1 FP/image (range 0-4) from 53 ground-truth lesions. Sensitivity analysis showed lesions &gt; 2mm3 had excellent detection performance. AI-based Maximum 2D Diameter and GLCM Difference Entropy were significantly associated with NA vs. PY subtypes across 29 lesions with available outcomes. Conclusions: AI-based models have potential for CT-based disease characterization of liver metastases in mSCLC.

KMT2C deficiency promotes small cell lung cancer metastasis through DNMT3A-mediated epigenetic reprogramming.

Small cell lung cancer (SCLC) is notorious for its early and frequent metastases, which contribute to it as a recalcitrant malignancy. To understand the molecular mechanisms underlying SCLC metastasis, we generated SCLC mouse models with orthotopically transplanted genome-edited lung organoids and performed multiomics analyses. We found that a deficiency of KMT2C, a histone H3 lysine 4 methyltransferase frequently mutated in extensive-stage SCLC, promoted multiple-organ metastases in mice. Metastatic and KMT2C-deficient SCLC displayed both histone and DNA hypomethylation. Mechanistically, KMT2C directly regulated the expression of DNMT3A, a de novo DNA methyltransferase, through histone methylation. Forced DNMT3A expression restrained metastasis of KMT2C-deficient SCLC through repressing metastasis-promoting MEIS/HOX genes. Further, S-(5'-adenosyl)-L-methionine, the common cofactor of histone and DNA methyltransferases, inhibited SCLC metastasis. Thus, our study revealed a concerted epigenetic reprogramming of KMT2C- and DNMT3A-mediated histone and DNA hypomethylation underlying SCLC metastasis, which suggested a potential epigenetic therapeutic vulnerability.

Survival Risk Analysis of Small Cell Lung Cancer Patients with Pre-Existing Type 2 Diabetes Mellitus: A Single-Center Retrospective Cohort Study.

PurposeWe aimed to investigate the clinicopathological characteristics and survival risk factors in small cell lung cancer (SCLC) patients with preexisting type 2 diabetes mellitus (preDM).Patients and MethodsAll patients with SCLC admitted to our hospital between January 2013 and August 2018 were followed up until August 2020 and retrospectively analyzed. Clinical characteristics of SCLC patients with and without preDM were extracted. Cox proportional hazards models were conducted to identify potential independent prognostic factors.ResultsOf 628 eligible individuals, 88 individuals had preDM. preDM was independently significantly associated with distant metastasis in all SCLC patients (p =0.016, OR=1.80, 95% CI 1.11–2.91), while preDM did not affect the outcome of SCLC patients (p=0.803, HR=1.04, 95% CI 0.79–1.36) by multivariate analysis. In the preDM group, the median overall survival (OS) was shorter in the insulin group than in the non insulin group (13.93 months versus 21.77 months, p=0.024). Multivariate analysis identified that insulin treatment was an independent unfavorable factor associated with OS (p =0.009, HR=2.10, 95% CI 1.19–3.64). In addition, poorer performance status (PS) and liver metastasis were also independent unfavorable prognostic factors (all p<0.01), while thoracic therapy significantly improved OS and decreased mortality risk in diabetic patients with SCLC (p<0.05).ConclusionpreDM may promote distant metastasis of SCLC while it is insulin therapy and not preDM which adversely affects the prognosis of SCLC patients. These findings indicate that enhancing blood glucose control and reducing insulin analog use may be essential to the improvement of the long-term survival of the diabetic population with SCLC.

Identification of TAZ as the essential molecular switch in orchestrating SCLC phenotypic transition and metastasis.

Small-cell lung cancer (SCLC) is a recalcitrant cancer characterized by high metastasis. However, the exact cell type contributing to metastasis remains elusive. Using a Rb1L/L/Trp53L/L mouse model, we identify the NCAMhiCD44lo/– subpopulation as the SCLC metastasizing cell (SMC), which is progressively transitioned from the non-metastasizing NCAMloCD44hi cell (non-SMC). Integrative chromatin accessibility and gene expression profiling studies reveal the important role of the SWI/SNF complex, and knockout of its central component, Brg1, significantly inhibits such phenotypic transition and metastasis. Mechanistically, TAZ is silenced by the SWI/SNF complex during SCLC malignant progression, and its knockdown promotes SMC transition and metastasis. Importantly, ectopic TAZ expression reversely drives SMC-to-non-SMC transition and alleviates metastasis. Single-cell RNA-sequencing analyses identify SMC as the dominant subpopulation in human SCLC metastasis, and immunostaining data show a positive correlation between TAZ and patient prognosis. These data uncover high SCLC plasticity and identify TAZ as the key molecular switch in orchestrating SCLC phenotypic transition and metastasis.

MEG3 LncRNA from Exosomes Released from Cancer-Associated Fibroblasts Enhances Cisplatin Chemoresistance in SCLC via a MiR-15a-5p/CCNE1 Axis.

PurposeLong non-coding RNAs (lncRNAs) may act as oncogenes in small-cell lung cancer (SCLC). Exosomes containing lncRNAs released from cancer-associated fibroblasts (CAF) accelerate tumorigenesis and confer chemoresistance. This study aimed to explore the action mechanism of the CAF-derived lncRNA maternally expressed gene 3 (MEG3) on cisplatin (DDP) chemoresistance and cell processes in SCLC.Materials and MethodsQuantitative real-time PCR was conducted to determine the expression levels of MEG3, miR-15a-5p, and CCNE1. Cell viability and metastasis were measured by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-h-tetrazolium bromide and invasion assays, respectively. A xenograft tumor model was developed to confirm the effect of MEG3 overexpression on SCLC progression in vivo. Relationships between miR-15a-5p and MEG3/CCNE1 were predicted using StarBase software and validated by dual luciferase reporter assay. Western blotting was used to determine protein levels. A co-culture model was established to explore the effects of exosomes on MEG3 expression in SCLC cell lines.ResultsMEG3 was overexpressed in SCLC tissues and cells. MEG3 silencing significantly repressed cell viability and metastasis in SCLC. High expression of MEG3 was observed in CAF-derived conditioned medium (CM) and exosomes, and promoted chemoresistance and cancer progression. Additionally, MEG3 was found to serve as a sponge of miR-15a-5p to mediate CCNE1 expression. Overexpression of miR-15a-5p and knockout of CCNE1 reversed the effects of MEG3 overexpression on cell viability and metastasis.ConclusionMEG3 lncRNA released from CAF-derived exosomes promotes DDP chemoresistance via regulation of a miR-15a-5p/CCNE1 axis. These findings may provide insight into SCLC therapy.

A Case of Secondary Tracheal and Bronchial Metastasis of Small-cell Lung Cancer Showing Lymphatic Metastasis

A Case of Secondary Tracheal and Bronchial Metastasis of Small-cell Lung Cancer Showing Lymphatic Metastasis

Pathways in small cell lung cancer and its therapeutic perspectives.

Small cell lung cancer (SCLC) is known for its rapid growth with high metastatic spread. Its treatment remains a major challenge for oncologists due to the high mutation rate and other clinical disadvantages. The survival rate of these patients is very poor but there is no significant progress over the last few decades in the treatment protocols. Hence there is an urgency to design new clinical trials with novel drug combinations that can specifically and effectively target key pathways for proper treatment of SCLC. There have been several indications that developmental signalling pathways are involved in tumor growth, progression, metastasis and invasion of SCLC. Thus, it is anticipated that deciphering the signalling cascades of these embryonic signalling pathways may reveal novel therapeutic breakthroughs in SCLC. In this context, we have tried to assemble all the relevant information to give an updated overview of the various signalling pathways involved in the development of SCLC.

Anlotinib for patients with small cell lung cancer and baseline liver metastases: A post hoc analysis of the ALTER 1202 trial.

Liver metastasis is common in advanced small cell lung cancer (SCLC). There is no evidence‐proven treatment beyond the second line in patients with SCLC and liver metastasis. This study aimed to investigate survival in patients with SCLC and liver metastasis treated with anlotinib compared with placebo. This study was a post hoc analysis of the phase II ALTER 1202 trial, including patients who had liver metastasis at baseline. The participants were randomized 2:1 to receive either 12 mg/day anlotinib (anlotinib group) or placebo (placebo group). Tumor response, progression‐free survival (PFS), and overall survival (OS) were compared. In the original trial, there were 39 participants with liver metastasis at baseline, including 27 and 12 in the anlotinib and placebo groups, respectively. The objective response rate was 3.7% and 0% in the anlotinib and placebo groups, respectively (p = 0.9999). An elevated disease control rate was found in the anlotinib group (44.4%) compared with the placebo group (8.3%, p = 0.0173). The median PFS was 1.51 vs. 0.71 months in favor of anlotinib (hazard ratio [HR] = 0.365, 95% confidence interval [CI]: 0.17–0.78; p = 0.0064), with no marked difference in median OS (3.29 vs. 1.91 months; HR = 0.51, 95% CI: 0.22–1.16; p = 0.0996). The most common AEs in the anlotinib group were hypertension (40.7%), fatigue (29.6%), loss of appetite (22.2%), and weight loss (22.2%). There were no grade 5 AE. In conclusion, anlotinib increased PFS compared with placebo in patients with SCLC and liver metastasis.

Treatment and Prevention of Brain Metastases in Small Cell Lung Cancer.

Central nervous system (CNS) metastasis will develop in 50% of small cell lung cancer (SCLC) patients throughout disease course. Development of CNS metastasis poses a particular treatment dilemma due to the accompanied cognitive changes, poor permeability of the blood-brain barrier to systemic therapy and relatively advanced state of disease. Survival of patients with untreated SCLC brain metastases is generally <3 months with whole brain radiotherapy used as first-line management in most SCLC patients. To prevent development of CNS metastasis prophylactic cranial irradiation (PCI) is recommended in limited stage disease, after response to chemotherapy and radiation, while PCI may be considered in extensive stage disease after favorable response to upfront treatment. Neurocognitive toxicity with whole brain radiotherapy and PCI is a concern and remains difficult to predict. The mechanism of toxicity is likely multifactorial, but a potential mechanism of injury to the hippocampus has led to hippocampal sparing radiation techniques. Treatment of established non-small cell lung cancer CNS metastases has increasingly focused on using stereotactic radiotherapy (SRS) and it is tempting to extrapolate these results to SCLC. In this review, we explore the evidence surrounding the prediction, prevention, detection, and treatment of CNS metastases in SCLC. We further review whether existing evidence supports extrapolating less toxic treatments to SCLC patients with CNS metastases and discuss trials that may shed more light on this question.