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.

C-Myc protein expression indicates unfavorable clinical outcome in surgically resected small cell lung cancer.

BACKGROUND: By being highly involved in the tumor evolution and disease progression of small cell lung cancer (SCLC), Myc family members (C-Myc, L-Myc, and N-Myc) might represent promising targetable molecules. Our aim was to investigate the expression pattern and prognostic relevance of these oncogenic proteins in an international cohort of surgically resected SCLC tumors. METHODS: Clinicopathological data and surgically resected tissue specimens from 104 SCLC patients were collected from two collaborating European institutes. Tissue sections were stained by immunohistochemistry (IHC) for all three Myc family members and the recently introduced SCLC molecular subtype-markers (ASCL1, NEUROD1, POU2F3, and YAP1). RESULTS: IHC analysis showed C-Myc, L-Myc, and N-Myc positivity in 48%, 63%, and 9% of the specimens, respectively. N-Myc positivity significantly correlated with the POU2F3-defined molecular subtype (r = 0.6913, p = 0.0056). SCLC patients with C-Myc positive tumors exhibited significantly worse overall survival (OS) (20 vs. 44 months compared to those with C-Myc negative tumors, p = 0.0176). Ultimately, in a multivariate risk model adjusted for clinicopathological and treatment confounders, positive C-Myc expression was confirmed as an independent prognosticator of impaired OS (HR 1.811, CI 95% 1.054-3.113, p = 0.032). CONCLUSIONS: Our study provides insights into the clinical aspects of Myc family members in surgically resected SCLC tumors. Notably, besides showing that positivity of Myc family members varies across the patients, we also reveal that C-Myc protein expression independently correlates with worse survival outcomes. Further studies are warranted to investigate the role of Myc family members as potential prognostic and predictive markers in this hard-to-treat disease.

Dual targeting of BCL-2 and MCL-1 in the presence of BAX breaks venetoclax resistance in human small cell lung cancer.

BACKGROUND: No targeted drugs are currently available against small cell lung cancer (SCLC). BCL-2 family members are involved in apoptosis regulation and represent therapeutic targets in many malignancies. METHODS: Expression of BCL-2 family members in 27 SCLC cell lines representing all known four SCLC molecular subtypes was assessed by qPCR, Western blot and mass spectrometry-based proteomics. BCL-2 and MCL-1 inhibition (venetoclax and S63845, respectively) was assessed by MTT assay and flow cytometry and in mice bearing human SCLC tumours. Drug interactions were calculated using the Combenefit software. Ectopic BAX overexpression was achieved by expression plasmids. RESULTS: The highest BCL-2 expression levels were detected in ASCL1- and POU2F3-driven SCLC cells. Although sensitivity to venetoclax was reflected by BCL-2 levels, not all cell lines responded consistently despite their high BCL-2 expression. MCL-1 overexpression and low BAX levels were both characteristic for venetoclax resistance in SCLC, whereas the expression of other BCL-2 family members did not affect therapeutic efficacy. Combination of venetoclax and S63845 resulted in significant, synergistic in vitro and in vivo anti-tumour activity and apoptosis induction in double-resistant cells; however, this was seen only in a subset with detectable BAX. In non-responding cells, ectopic BAX overexpression sensitised to venetoclax and S63845 and, furthermore, induced synergistic drug interaction. CONCLUSIONS: The current study reveals the subtype specificity of BCL-2 expression and sheds light on the mechanism of venetoclax resistance in SCLC. Additionally, we provide preclinical evidence that combined BCL-2 and MCL-1 targeting is an effective approach to overcome venetoclax resistance in high BCL-2-expressing SCLCs with intact BAX.

Laser ablation-inductively coupled plasma-mass spectrometry analysis reveals differences in chemotherapeutic drug distribution in surgically resected pleural mesothelioma.

AIMS: Pleural mesothelioma (PM) is a highly aggressive thoracic tumour with poor prognosis. Although reduced tissue drug accumulation is one of the key features of platinum (Pt) resistance, little is known about Pt distribution in human PM. METHODS: We assessed Pt levels of blood samples and surgically resected specimens from 25 PM patients who had received neoadjuvant Pt-based chemotherapy (CHT). Pt levels and tissue distributions were measured by laser ablation-inductively coupled plasma-mass spectrometry and correlated with clinicopathological features. RESULTS: In surgically resected PM specimens, mean Pt levels of nontumourous (fibrotic) areas were significantly higher (vs tumourous regions, P = 0.0031). No major heterogeneity of Pt distribution was seen within the tumourous areas. Pt levels correlated neither with the microvessel area nor with apoptosis rate in the tumourous or nontumourous regions. A significant positive correlation was found between serum and both full tissue section and tumourous area mean Pt levels (r = 0.532, P = 0.006, 95% confidence interval [95% CI] 0.161-0.771 and r = 0.415, P = 0.039, 95% CI 0.011-0.702, respectively). Furthermore, a significant negative correlation was detected between serum Pt concentrations and elapsed time from the last cycle of CHT (r = -0.474, P = 0.017, 95% CI -0.738--0.084). Serum Pt levels correlated negatively with overall survival (OS) (P = 0.029). CONCLUSIONS: There are major differences in drug distribution between tumourous and nontumourous areas of PM specimens. Serum Pt levels significantly correlate with full section and tumourous area average Pt levels, elapsed time from the last CHT cycle, and OS. Further studies investigating clinicopathological factors that modulate tissue Pt concentration and distribution are warranted.

Expression patterns and prognostic relevance of subtype-specific transcription factors in surgically resected small-cell lung cancer: an international multicenter study.

The tissue distribution and prognostic relevance of subtype-specific proteins (ASCL1, NEUROD1, POU2F3, YAP1) present an evolving area of research in small-cell lung cancer (SCLC). The expression of subtype-specific transcription factors and P53 and RB1 proteins were measured by immunohistochemistry (IHC) in 386 surgically resected SCLC samples. Correlations between subtype-specific proteins and in vitro efficacy of various therapeutic agents were investigated by proteomics and cell viability assays in 26 human SCLC cell lines. Besides SCLC-A (ASCL1-dominant), SCLC-AN (combined ASCL1/NEUROD1), SCLC-N (NEUROD1-dominant), and SCLC-P (POU2F3-dominant), IHC and cluster analyses identified a quadruple-negative SCLC subtype (SCLC-QN). No unique YAP1-subtype was found. The highest overall survival rates were associated with non-neuroendocrine subtypes (SCLC-P and SCLC-QN) and the lowest with neuroendocrine subtypes (SCLC-A, SCLC-N, SCLC-AN). In univariate analyses, high ASCL1 expression was associated with poor prognosis and high POU2F3 expression with good prognosis. Notably, high ASCL1 expression influenced survival outcomes independently of other variables in a multivariate model. High POU2F3 and YAP1 protein abundances correlated with sensitivity and resistance to standard-of-care chemotherapeutics, respectively. Specific correlation patterns were also found between the efficacy of targeted agents and subtype-specific protein abundances. In conclusion, we investigated the clinicopathological relevance of SCLC molecular subtypes in a large cohort of surgically resected specimens. Differential IHC expression of ASCL1, NEUROD1, and POU2F3 defines SCLC subtypes. No YAP1-subtype can be distinguished by IHC. High POU2F3 expression is associated with improved survival in a univariate analysis, whereas elevated ASCL1 expression is an independent negative prognosticator. Proteomic and cell viability assays of human SCLC cell lines revealed distinct vulnerability profiles defined by transcription regulators. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Impact of fibrinogen levels and modified Glasgow prognostic score on survival of stage III/N2 non-small cell lung cancer patients treated with neoadjuvant therapy and radical resection.

PURPOSE: The prognostic value of pretreatment and preoperative fibrinogen plasma levels and the modified Glasgow prognostic score (mGPS) in stage III/N2 non-small cell lung cancer (NSCLC) patients who receive neoadjuvant treatment followed by radical surgery is yet unclear. METHODS: Fibrinogen levels and mGPS of 84 patients with initial stage III/N2 NSCLC, who received neoadjuvant therapy followed by complete surgical resection from 2002 to 2014 were retrospectively analyzed and correlated with clinical parameters and overall survival (OS). Data were analyzed using log-rank and Cox regression analysis adjusted for clinical and pathological factors. RESULTS: Median serum fibrinogen level after neoadjuvant treatment was 439 mg/dL (IQR 158 mg/dL). Elevated fibrinogen levels (> 400 mg/dL) after neoadjuvant treatment were significantly associated with poorer OS (28.2 months vs. 60.9 months, HR 0.562, p = 0.048). Importantly, a decrease in fibrinogen levels after neoadjuvant treatment (n = 34) was found to be an independent predictor for favorable OS in multivariate analysis (HR 0.994, p = 0.025). Out of 80 patients, 55, 19 and 6 patients had a mGPS of 0, 1 and 2, respectively. Moreover, elevated mGPS after neoadjuvant treatment (mGPS 1-2) showed a non-significant trend for poorer OS compared to mGPS 0 (28.2 vs. 46.5 months, HR 0.587, p = 0.066). CONCLUSION: Elevated fibrinogen levels after neoadjuvant therapy prior to surgery in stage III/N2 NSCLC patients are associated with significant disadvantage for OS. A decrease in fibrinogen levels after neoadjuvant therapy was found to be a predictor for superior OS in this retrospective patient cohort.

FGF2 and EGF induce epithelial-mesenchymal transition in malignant pleural mesothelioma cells via a MAPKinase/MMP1 signal.

Malignant pleural mesothelioma (MPM), an aggressive malignancy affecting pleural surfaces, occurs in three main histological subtypes. The epithelioid and sarcomatoid subtypes are characterized by cuboid and fibroblastoid cells, respectively. The biphasic subtype contains a mixture of both. The sarcomatoid subtype expresses markers of epithelial-mesenchymal transition (EMT) and confers the worst prognosis, but the signals and pathways controlling EMT in MPM are not well understood. We demonstrate that treatment with FGF2 or EGF induced a fibroblastoid morphology in several cell lines from biphasic MPM, accompanied by scattering, decreased cell adhesion and increased invasiveness. This depended on the MAP-kinase pathway but was independent of TGFß or PI3-kinase signaling. In addition to changes in known EMT markers, microarray analysis demonstrated differential expression of MMP1, ESM1, ETV4, PDL1 and BDKR2B in response to both growth factors and in epithelioid versus sarcomatoid MPM. Inhibition of MMP1 prevented FGF2-induced scattering and invasiveness. Moreover, in MPM cells with sarcomatoid morphology, inhibition of FGF/MAP-kinase signaling induced a more epithelioid morphology and gene expression pattern. Our findings suggest a critical role of the MAP-kinase axis in the morphological and behavioral plasticity of mesothelioma.

The evidence for and against different modes of tumour cell extravasation in the lung: diapedesis, capillary destruction, necroptosis, and endothelialization.

The development of lung metastasis is a significant negative prognostic factor for cancer patients. The extravasation phase of lung metastasis involves interactions of tumour cells with the pulmonary endothelium. These interactions may have broad biological and medical significance, with potential clinical implications ranging from the discovery of lung metastasis biomarkers to the identification of targets for intervention in preventing lung metastases. Because of the potential significance, the mechanisms of tumour cell extravasation require cautious, systematic studies. Here, we discuss the literature pertaining to the proposed mechanisms of extravasation and critically compare a recently proposed mechanism (tumour cell-induced endothelial necroptosis) with the already described extravasation mechanisms in the lung. We also provide novel data that may help to explain the underlying physiological basis for endothelialization as a mechanism of tumour cell extravasation in the lung. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Trimodality therapy for Pancoast tumors: T4 is not a contraindication to radical surgery.

OBJECTIVE: This study aims to evaluate the impact of T stage and extended surgery on the outcome of patients with Pancoast tumors after induction chemoradiation therapy. METHODS: Forty-six consecutive patients who underwent chemoradiation therapy (platin-based, 45-66 Gy) followed by surgery between 1998 and 2013 were retrospectively reviewed and analyzed. RESULTS: In 28 (61%) patients with T4 tumors, extended procedures (more than rib resection) were performed. There were 37 (80%) lobectomies, 6 (13%) pneumonectomies, and 3 (7%) sublobar resections. A total of 44 (96%) patients had R0 resection. About 30-day mortality was 0%, major surgical complications occurred in 9 (19.6%) patients. Overall survival (OS) at 5-years was 63%. Disease-free survival (DFS) at 5-years was 45%. At multivariate cox regression analysis adjusted for clinical factors, T factor (T3/T4) and extended surgical procedures did not impact survival. However, pathological positive N stage had a negative impact on OS and lack of pathological response negatively impacted both OS and DFS. CONCLUSION: Trimodality treatment including radical resection for Pancoast tumors provides good surgical outcome and favorable long-term results. Survival of patients with T4 tumors and extended surgical procedures comparable to that of patients with T3 tumors undergoing rib resection only.

A rare indication for lung transplantation - pulmonary alveolar microlithiasis: institutional experience of five consecutive cases.

BACKGROUND: Pulmonary alveolar microlithiasis (PAM) is a rare lung disease caused by calcifications within the alveolar space. The only known effective treatment for an end-stage PAM is lung transplantation (LuTX). METHODS: We performed a retrospective chart review of all individuals that underwent lung transplantation at our center between 1989 and 2013. Five consecutive patients with PAM were identified. RESULTS: Four females and one male with a mean age of 46.3 yr were identified. Extracorporeal membrane oxygenation (ECMO) support was required intraoperatively in four cases and post-operatively in one case. Mean post-operative intubation time was 3.3 (range, 2-5) d and mean intensive care unit (ICU) stay was 8.3 (range, 4-12) d. No intraoperative complications were observed. One early patient (operated in 1995) underwent acute re-transplantation on the second post-operative day (POD) and died from sepsis on the 11 POD. In one patient reperfusion edema was observed requiring a prolonged weaning process. No other severe perioperative complications were observed. Four of five patients are currently still alive with normal follow-up parameters. No recurrence of PAM was observed. CONCLUSIONS: Lung transplantation is a feasible therapy option in patients with end-stage PAM showing good post-operative results comparable to other indications for LuTX.

Lung transplantation in patients with incidental early stage lung cancer-institutional experience of a high volume center.

BACKGROUND: Incidentally discovered lung cancers in lung transplant (LuTX) recipients are rare but may affect outcome. We aim to report our single center experience with incidence, management, and survival of patients with previously unverified primary lung cancer discovered at the time of LuTX. METHODS: A total of 1262 patients undergoing LuTX between 1989 and 2012 were retrospectively analyzed in our prospective database. RESULTS: Patients identified were six men and five women with a mean age of 54.4±9.9 years. The indication for LuTX was COPD (n=9), pulmonary fibrosis (n=1), and cystic fibrosis (n=1). Histological diagnosis of the explanted lung revealed adenocarcinoma in six, squamous cell carcinoma in three, and lepidic predominant adenocarcinoma in two cases, respectively. Staging revealed stage IA (pT1a/b pN0) in eight and IB (pT2a pN0) in two cases and one patient in stage IIA (pT1b pN1). Subsequent cancer staging after LuTX revealed no metastasis. Immunosuppression was adjusted and no adjuvant chemo- or radiotherapy was administered. The 5-year survival rate was 90.5% with no detection of recurrence. CONCLUSION: In patients with incidentally detected early stage lung cancer at the time of LuTX, rates of recurrence and survival based on this sample appear to be acceptable.

Epigenetic down-regulation of integrin α7 increases migratory potential and confers poor prognosis in malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is a devastating malignancy characterized by invasive growth and rapid recurrence. The identification and inhibition of molecular components leading to this migratory and invasive phenotype are thus essential. Accordingly, a genome-wide expression array analysis was performed on MPM cell lines and a set of 139 genes was identified as differentially expressed in cells with high versus low migratory activity. Reduced expression of the novel tumour suppressor integrin α7 (ITGA7) was found in highly motile cells. A significant negative correlation was observed between ITGA7 transcript levels and average displacement of cells. Forced overexpression of ITGA7 in MPM cells with low endogenous ITGA7 expression inhibited cell motility, providing direct evidence for the regulatory role of ITGA7 in MPM cell migration. MPM cells showed decreased ITGA7 expressions at both transcription and protein levels when compared to non-malignant mesothelial cells. The majority of MPM cell cultures displayed hypermethylation of the ITGA7 promoter when compared to mesothelial cultures. A statistically significant negative correlation between ITGA7 methylation and ITGA7 expression was also observed in MPM cells. While normal human pleura samples unambiguously expressed ITGA7, a varying level of expression was found in a panel of 200 human MPM samples. In multivariate analysis, ITGA7 expression was found to be an independent prognostic factor. Although there was no correlation between histological subtypes and ITGA7 expression, importantly, patients with high tumour cell ITGA7 expression had an increased median overall survival compared to the low- or no-expression groups (463 versus 278 days). In conclusion, our data suggest that ITGA7 is an epigenetically regulated tumour suppressor gene and a prognostic factor in human MPM.

Fibulin-3 levels in malignant pleural mesothelioma are associated with prognosis but not diagnosis.

BACKGROUND: Fibulin-3 (FBLN3) was recently presented as a promising novel biomarker for malignant pleural mesothelioma (MPM), warranting independent validation studies. METHODS: ELISA was used to measure cellular and secreted FBLN3 in cell lines, in plasma of xenograft tumour-bearing mice, in plasma from two independent series of MPM and non-MPM patients and in pleural fluid from a third series. Diagnostic and prognostic potential of FBLN3 was assessed by receiver operating characteristics curve analysis and Kaplan-Meier method, respectively. RESULTS: FBLN3 was expressed in all MPM and benign mesothelial cell lines tested, and a correlation was observed between cellular protein expression and secreted levels. Human FBLN3 was detectable in plasma of tumour-bearing mice, suggesting that MPM cells contribute to levels of circulating FBLN3. Plasma FBLN3 was significantly elevated in MPM patients from the Sydney cohort, but not the Vienna cohort, but the diagnostic accuracy was low (63%, (95% CI: 50.1-76.4) and 56% (95% CI: 41.5-71.0), respectively). Although FBLN3 levels in pleural effusions were not significantly different between cases and controls, FBLN3 levels in pleural effusion fluid were found to be independently associated with prognosis (hazard ratio of 9.92 (95% CI: 2.14-45.93)). CONCLUSIONS: These data confirm the potential prognostic value of pleural effusion FBLN3, but question the diagnostic value of this protein in MPM patients.

Cell migration or cytokinesis and proliferation?--revisiting the "go or grow" hypothesis in cancer cells in vitro.

The mortality of patients with solid tumors is mostly due to metastasis that relies on the interplay between migration and proliferation. The "go or grow" hypothesis postulates that migration and proliferation spatiotemporally excludes each other. We evaluated this hypothesis on 35 cell lines (12 mesothelioma, 13 melanoma and 10 lung cancer) on both the individual cell and population levels. Following three-day-long videomicroscopy, migration, proliferation and cytokinesis-length were quantified. We found a significantly higher migration in mesothelioma cells compared to melanoma and lung cancer while tumor types did not differ in mean proliferation or duration of cytokinesis. Strikingly, we found in melanoma and lung cancer a significant positive correlation between mean proliferation and migration. Furthermore, non-dividing melanoma and lung cancer cells displayed slower migration. In contrast, in mesothelioma there were no such correlations. Interestingly, negative correlation was found between cytokinesis-length and migration in melanoma. FAK activation was higher in melanoma cells with high motility. We demonstrate that the cancer cells studied do not defer proliferation for migration. Of note, tumor cells from various organ systems may differently regulate migration and proliferation. Furthermore, our data is in line with the observation of pathologists that highly proliferative tumors are often highly invasive.

PD-L1 assessment in lung cancer biopsies-pitfalls and limitations.

The programmed cell death-ligand 1 (PD-L1) protein expression on tumor cells predicts the efficacy of immunotherapy in patients with non-small cell lung cancer. However, the assessment of PD-L1 expression on tumor cells has limited power for selecting patients for immunotherapy due to intra-tumoral heterogeneity and inter-tumoral heterogeneity of PD-L1 expression, the inter-observer variability in scoring PD-L1 staining, and reproducibility. These difficulties and pitfalls in interpreting the PD-L1 assessment are discussed in detail in this review.

Twenty four-month follow-up after bullectomy, unilateral and bilateral lung volume reduction surgery: a single-center retrospective analysis of consecutive cases.

PURPOSE: While pharmacologic therapy remains the cornerstone of lung emphysema treatment, surgery is an additional therapeutic option in selected patient groups with advanced emphysema. The aim of lung volume reduction surgery (LVRS) is to improve lung function, exercise capacity, quality of life and survival. We sought to determine the therapeutic value of surgical resection in specific patients with lung emphysema. PATIENTS AND METHODS: A retrospective study was performed consisting of 58 patients with lung emphysema who underwent surgical intervention over a 10-year period and were followed for 2 years postoperatively. The clinical characteristics recorded were FEV1 (forced expiratory volume in 1 s), the 6-min walk test (6-MWT), the Modified Medical Research Council (mMRC), body mass index (BMI) and quality of life prior to and 6, 12 and 24 months after surgical intervention. Moreover, all peri- and post-operative complications were noted. RESULTS: Out of 58 emphysema patients (72% male, FEV1 (L) 2.21 ± 0.17, RV (L) 3.39 ± 0.55), 19 underwent surgical bullectomy, 31 unilateral LVRS and 8 sequential bilateral LVRS. Six months after surgery, there was a statistically significant improvement in FEV1, RV, TLC, 6-MWT and mMRC. Over a period of 12 to 24 months postoperatively, clinical benefit gradually declines most likely due to COPD progression but patients still experienced a significant improvement in FEV1. The most common postoperative complications were persistent air leakage (> 7 days), arrhythmia and subcutaneous emphysema in 60%, 51.6% and 22.4%, respectively. No deaths were observed after surgical intervention. CONCLUSION: In a selected patient population, surgery led to significant improvement of lung function parameters, exercise capacity and quality of life. Over a period of 12 to 24 months postoperatively, clinical benefit gradually decreased most likely due to COPD progression.

Mesothelioma-associated fibroblasts enhance proliferation and migration of pleural mesothelioma cells via c-Met/PI3K and WNT signaling but do not protect against cisplatin.

BACKGROUND: Pleural mesothelioma (PM) is an aggressive malignancy with poor prognosis. Unlike many other cancers, PM is mostly characterized by inactivation of tumor suppressor genes. Its highly malignant nature in absence of tumor driving oncogene mutations indicates an extrinsic supply of stimulating signals by cells of the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are an abundant cell type of the TME and have been shown to drive the progression of several malignancies. The aim of the current study was to isolate and characterize patient-derived mesothelioma-associated fibroblasts (Meso-CAFs), and evaluate their impact on PM cells. METHODS: Meso-CAFs were isolated from surgical specimens of PM patients and analyzed by array comparative genomic hybridization, next generation sequencing, transcriptomics and proteomics. Human PM cell lines were retrovirally transduced with GFP. The impact of Meso-CAFs on tumor cell growth, migration, as well as the response to small molecule inhibitors, cisplatin and pemetrexed treatment was investigated in 2D and 3D co-culture models by videomicroscopy and automated image analysis. RESULTS: Meso-CAFs show a normal diploid genotype without gene copy number aberrations typical for PM cells. They express CAF markers and lack PM marker expression. Their proteome and secretome profiles clearly differ from normal lung fibroblasts with particularly strong differences in actively secreted proteins. The presence of Meso-CAFs in co-culture resulted in significantly increased proliferation and migration of PM cells. A similar effect on PM cell growth and migration was induced by Meso-CAF-conditioned medium. Inhibition of c-Met with crizotinib, PI3K with LY-2940002 or WNT signaling with WNT-C59 significantly impaired the Meso-CAF-mediated growth stimulation of PM cells in co-culture at concentrations not affecting the PM cells alone. Meso-CAFs did not provide protection of PM cells against cisplatin but showed significant protection against the EGFR inhibitor erlotinib. CONCLUSIONS: Our study provides the first characterization of human patient-derived Meso-CAFs and demonstrates a strong impact of Meso-CAFs on PM cell growth and migration, two key characteristics of PM aggressiveness, indicating a major role of Meso-CAFs in driving PM progression. Moreover, we identify signaling pathways required for Meso-CAF-mediated growth stimulation. These data could be relevant for novel therapeutic strategies against PM.

Primary and hTERT-Transduced Mesothelioma-Associated Fibroblasts but Not Primary or hTERT-Transduced Mesothelial Cells Stimulate Growth of Human Mesothelioma Cells.

Pleural mesothelioma (PM) is an aggressive malignancy that develops in a unique tumor microenvironment (TME). However, cell models for studying the TME in PM are still limited. Here, we have generated and characterized novel human telomerase reverse transcriptase (hTERT)-transduced mesothelial cell and mesothelioma-associated fibroblast (Meso-CAF) models and investigated their impact on PM cell growth. Pleural mesothelial cells and Meso-CAFs were isolated from tissue of pneumothorax and PM patients, respectively. Stable expression of hTERT was induced by retroviral transduction. Primary and hTERT-transduced cells were compared with respect to doubling times, hTERT expression and activity levels, telomere lengths, proteomes, and the impact of conditioned media (CM) on PM cell growth. All transduced derivatives exhibited elevated hTERT expression and activity, and increased mean telomere lengths. Cell morphology remained unchanged, and the proteomes were similar to the corresponding primary cells. Of note, the CM of primary and hTERT-transduced Meso-CAFs stimulated PM cell growth to the same extent, while CM derived from mesothelial cells had no stimulating effect, irrespective of hTERT expression. In conclusion, all new hTERT-transduced cell models closely resemble their primary counterparts and, hence, represent valuable tools to investigate cellular interactions within the TME of PM.

The usefulness of MMP-9, TIMP-1 and MMP-9/TIMP-1 ratio for diagnosis and assessment of COPD severity.

BACKGROUND: Inflammation, oxidative stress and an imbalance between proteases and protease inhibitors are recognized pathophysiological features of chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate serum levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in patients with COPD and to assess their relationship with lung function, symptom severity scores and recent acute exacerbations. METHODS: In this observational cohort study, serum levels of MMP-9 and TIMP-1 and the MMP-9/TIMP-1 ratio in the peripheral blood of COPD patients with stable disease and healthy controls were determined, and their association with lung function (postbronchodilator spirometry, body plethysmography, single breath diffusion capacity for carbon monoxide), symptom severity scores (mMRC and CAT) and exacerbation history were assessed. RESULTS: COPD patients (n = 98) had significantly higher levels of serum MMP-9 and TIMP-1 and a higher MMP-9/TIMP-1 ratio than healthy controls (n = 47) (p ≤ 0.001). The areas under the receiver operating characteristic curve for MMP-9, TIMP-1 and the MMP-9/TIMP-1 ratio for COPD diagnosis were 0.974, 0.961 and 0.910, respectively (all p < 0.05). MMP-9 and the MMP-9/TIMP-1 ratio were both negatively correlated with FVC, FEV1, FEV1/FVC, VC, and IC (all p < 0.05). For MMP-9, a positive correlation was found with RV/TLC% (p = 0.005), and a positive correlation was found for the MMP-9/TIMP-1 ratio with RV% and RV/TLC% (p = 0.013 and 0.002, respectively). Patients with COPD GOLD 3 and 4 presented greater MMP-9 levels and a greater MMP-9/TIMP-1 ratio compared to GOLD 1 and 2 patients (p ≤ 0.001). No correlation between diffusion capacity for carbon monoxide and number of acute exacerbations in the previous year was found. CONCLUSIONS: COPD patients have elevated serum levels of MMP-9 and TIMP-1 and MMP-9/TIMP-1 ratio. COPD patients have an imbalance between MMP-9 and TIMP-1 in favor of a pro-proteolytic environment, which overall indicates the importance of the MMP-9/TIMP-1 ratio as a potential biomarker for COPD diagnosis and severity.

Lymph Node Log-Odds Ratio Accurately Defines Prognosis in Resectable Non-Small Cell Lung Cancer.

OBJECTIVES: The ratio of positive and resected lymph nodes (LN ratio) has been shown to be prognostic in non-small cell lung cancer (NSCLC). Contrary to the LN ratio, calculating the LN log-odds ratio (LN-LOR) additionally considers the total number of resected lymph nodes. We aim to evaluate LN-LOR between positive and resected lymph nodes as a prognostic factor in operable NSCLC. METHODS: Patients with NSCLC who underwent curative intent lobectomy treated at two high-volume centers were retrospectively studied. LN-LOR was dichotomized according to impact on OS and further combined with N descriptors and correlated with clinical variables and survival. RESULTS: 944 patients were included. Cut-off analysis revealed that an LN-LOR of -0.34 significantly discriminated patients according to OS (p < 0.001, chi-squared test 41.26). When combined with N1 and N2 descriptors, LN-LOR low risk (median OS not reached and 83 months) and LN-LOR high-risk patients (median OS 50 and 59 months) had similar survival irrespective of the anatomical location of the positive lymph nodes. Multivariable Cox regression analysis revealed that age (HR 1.02, 95% CI 1.001-1.032), sex (male, HR 1.65, 95% CI 1.25-2.19), histological subtype (HR 2.11, 95% CI 1.35-3.29), pathological stage (HR 1.23, 95% CI 1.01-1.45) and LN-LOR risk groups (low risk, HR 0.48, 95% CI 0.32-0.72) were independent prognostic factors for OS. CONCLUSIONS: This retrospective two-center analysis shows that LN-LOR is significantly associated with OS in resectable NSCLC and might better reflect the biological behavior of the disease, regardless of anatomical lymph node locations. This finding may additionally support the value of extensive LN dissection.