Prognostic significance of stem cell-related marker expression and its correlation with histologic subtypes in lung adenocarcinoma

Initiation of Cancer: The Journey From Mutations in Somatic Cells to Epigenetic Changes in Tissue-resident VSELs

Multiple theories exist to explain cancer initiation, although a consensus on this is crucial for developing effective therapies. 'Somatic mutation theory' suggests that mutations in somatic cells during DNA repair initiates cancer but this concept has several attached paradoxes. Research efforts to identify quiescent cancer stem cells (CSCs) that survive therapy and result in metastasis and recurrence have remained futile. In solid cancers, CSCs are suggested to appear during epithelial-mesenchymal transition by the dedifferentiation and reprogramming of epithelial cells. Pluripotent and quiescent very small embryonic-like stem cells (VSELs) exist in multiple tissues but remain elusive owing to their small size and scarce nature. VSELs are developmentally connected to primordial germ cells, undergo rare, asymmetrical cell divisions and are responsible for the regular turnover of cells to maintain tissue homeostasis throughout life. VSELs are directly vulnerable to extrinsic endocrine insults because they express gonadal and gonadotropin hormone receptors. VSELs undergo epigenetic changes due to endocrine insults and transform into CSCs. CSCs exhibit genomic instability and develop mutations due to errors during DNA replication while undergoing excessive proliferation and clonal expansion to form spheroids. Thus tissue-resident VSELs offer a connection between extrinsic insults and variations in cancer incidence reported in various body tissues. To conclude, cancer is indeed a stem cell disease with mutations occurring as a consequence. In addition to immunotherapy, targeting mutations, and Lgr5 + organoids for developing new therapeutics, targeting CSCs (epigenetically altered VSELs) by improving their niche and epigenetic status could serve as a promising strategy to treat cancer.

The Clinical Significance and Prognostic Value of ALDH1 Expression in Non-small Cell Lung Cancer: A Systematic Review and Meta-analysis

BACKGROUND

The results of the association between aldehyde dehydrogenase 1 (ALDH1) expression and prognosis of non-small cell lung cancer (NSCLC) are contradictory. We conducted this meta-analysis to investigate the clinical significance and prognostic value of ALDH1 in NSCLC.

METHODS

The databases PubMed, Web of Science, EMBASE, the Cochrane Library, Wanfang, and CNKI were systematically queried to identify eligible studies. The retrieval time was from database establishment to August 2023. We evaluated the correlation between ALDH1 expression and clinical features of NSCLC by employing odds ratios (ORs) and 95% confidence intervals (95% CIs). In addition, we used hazard ratios (HRs) and 95% CIs to evaluate the role of ALDH1 expression in the prognosis of NSCLC.

RESULTS

Our study included 21 literatures involving 2721 patients. The expression of ALDH1 in NSCLC was higher than that in normal tissues (OR = 6.04, 95% CI: 1.25-29.27, P = 0.026). The expression of ALDH1 was related to TNM stage (OR = 1.81, 95% CI: 1.06-3.09, P = 0.029), tumor grade (OR = 0.29, 95% CI: 0.17-0.48, P < 0.0001), lymph node metastasis (OR = 2.60, 95% CI: 1.52-4.45, P = 0001) and histological subtype (OR = 0.67, 95% CI: 0.52-0.86, P = 0.002). In patients with NSCLC, we found that the over-expression of ALDH1 was significantly associated with poor overall survival (OS) (HR = 1.44, 95% CI: 1.15-1.81, P = 0.002) and disease-free survival (DFS) (HR = 1.74, 95% CI: 1.45-2.10, P < 0.0001).

CONCLUSION

The expression of ALDH1 is closely associated with the clinicopathologic characteristics and prognosis of NSCLC. ALDH1 may serve as a valuable clinical assessment tool and prognostic predictor in NSCLC.

Cancer Stem Cell-Like Circulating Tumor Cells Are Prognostic in Non-Small Cell Lung Cancer

Despite recent advances in the treatment of non-small cell lung cancer (NSCLC), less than 10% of patients survive the first five years when the disease has already spread at primary diagnosis. Methods: Blood samples were taken from 118 NSCLC patients at primary diagnosis or at progression of the disease before the start of a new treatment line and enriched for circulating tumor cells (CTCs) by microfluidic Parsortix™ (Angle plc, Guildford GU2 7AF, UK) technology. The gene expression of epithelial cancer stem cell (CSC), epithelial to mesenchymal (EMT), and lung-related markers was assessed by qPCR, and the association of each marker with overall survival (OS) was evaluated using log-rank tests. Results: EpCAM was the most prevalent transcript, with 53.7% positive samples at primary diagnosis and 25.6% at recurrence. EpCAM and CK19, as well as NANOG, PROM1, TERT, CDH5, FAM83A, and PTHLH transcripts, were associated with worse OS. However, only the CSC-specific NANOG and PROM1 were related to the outcome both at primary diagnosis (NANOG: HR 3.21, 95%CI 1.02–10.14, p = 0.016; PROM1: HR 4.23, 95% CI 0.65–27.56, p = 0.007) and disease progression (NANOG: HR 4.17, 95%CI 0.72–24.14, p = 0.025; PROM1: HR 4.77, 95% CI 0.29–78.94, p = 0.032). Conclusions: The present study further underlines the relevance of the molecular characterization of CTCs. Our multi-marker analysis highlighted the prognostic value of cancer stem cell-related transcripts at primary diagnosis and disease progression.

Modulation of Immune Components on Stem Cell and Dormancy in Cancer

Cancer stem cells (CSCs) refer to a certain subpopulation within the tumor entity that is characterized by restricted cellular proliferation and multipotent differentiation potency. The existence of CSCs has been proven to contribute to the heterogeneity of malignancies, accounting for intensified tumorigenesis, treatment resistance, and metastatic spread. Dormancy was proposed as a reversible state of cancer cells that are temporarily arrested in the cell cycle, possessing several hallmarks that facilitate their survival within a devastating niche. This transient period is evoked to enter an actively proliferating state by multiple regulatory alterations, and one of the most significant and complex factors comes from local and systemic inflammatory reactions and immune components. Although CSCs and dormant cancer cells share several similarities, the clear relationship between these two concepts remains unclear. Thus, the detailed mechanism of immune cells interacting with CSCs and dormant cancer cells also warrants elucidation for prevention of cancer relapse and metastasis. In this review, we summarize recent findings and prospective studies on CSCs and cancer dormancy to conclude the relationship between these two concepts. Furthermore, we aim to outline the mechanism of immune components in interfering with CSCs and dormant cancer cells to provide a theoretical basis for the prevention of relapse and metastasis.

Lung-Resident Mesenchymal Stem Cell Fates within Lung Cancer

Simple Summary

Lung cancer remains the leading cause of cancer-related deaths worldwide. Herein, the heterogeneous tumor stroma decisively impacts on tumor progression, therapy resistance, and, thus, poor clinical outcome. Among the numerous non-epithelial cells constructing the complex environment of lung carcinomas, mesenchymal stem cells (MSC) gained attraction being stromal precursor cells that could be recruited and ‘educated’ by lung cancer cells to adopt a tumor-associated MSC phenotype, serve as source for activated fibroblasts and presumably for vascular mural cells finally reinforcing tumor progression. Lung-resident MSCs should be considered as ‘local MSCs in stand by’ ready to be arranged within the cancer stroma.

Abstract

Lung-resident mesenchymal stem cells (LR-MSCs) are non-hematopoietic multipotent stromal cells that predominately reside adventitial within lung blood vessels. Based on their self-renewal and differentiation properties, LR-MSCs turned out to be important regulators of normal lung homeostasis. LR-MSCs exert beneficial effects mainly by local secretion of various growth factors and cytokines that in turn foster pulmonary regeneration including suppression of inflammation. At the same time, MSCs derived from various tissues of origins represent the first choice of cells for cell-based therapeutic applications in clinical medicine. Particularly for various acute as well as chronic lung diseases, the therapeutic applications of exogenous MSCs were shown to mediate beneficial effects, hereby improving lung function and survival. In contrast, endogenous MSCs of normal lungs seem not to be sufficient for lung tissue protection or repair following a pathological trigger; LR-MSCs could even contribute to initiation and/or progression of lung diseases, particularly lung cancer because of their inherent tropism to migrate towards primary tumors and metastatic sites. However, the role of endogenous LR-MSCs to be multipotent tumor-associated (stromal) precursors remains to be unraveled. Here, we summarize the recent knowledge how ‘cancer-educated’ LR-MSCs impact on lung cancer with a focus on mesenchymal stem cell fates.

Co-culturing polarized M2 Thp-1-derived macrophages enhance stemness of lung adenocarcinoma A549 cells

Background

The tumor microenvironment (TME) is highly associated with cancer stem cells, and affects tumor initiation, progression, and metastasis. This study aimed to explore the underlying molecular mechanism of induction of A549 cancer cell stemness by THP-1-derived macrophages.

Method

The Hedgehog inhibitor (Vismodegib), Notch inhibitor Gamma Secretase Inhibitor (GSI), and Signal Transducer and Activator of Transcription 3 (STAT3) inhibitor Cucurbitacin I (JSI-124) were added separately into the co-culture system of A549 cancer cell with THP-1-derived macrophages. Cell Counting Kit-8 (CCK-8) assay and the Cell-IQ continuous surveillance system were used to examine the cell growth and morphological changes of A549 cells. The messenger ribonucleic acid (mRNA) and protein expression levels of stem cell markers were respectively analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, and the activity of Acetaldehyde dehydrogenase (ALDH) enzyme was assessed by flow cytometry analysis. Enzyme-linked immunosorbent assay (ELISA) and qRT-PCR assays were performed to evaluate the activation and differentiation of macrophages.

Results

Results showed that the proliferation and stemness of A549 cells were significantly enhanced by co-culturing with THP-1-derived macrophages. The expression levels of Transforming growth factor-β (TGF-β) and Interleukin-6 (IL-6) in macrophages were notably increased after co-culturing with A549 cells. Meanwhile, co-culturing with A549 cells induced the polarization of macrophages towards the M2 phenotype. Moreover, the inhibitors could reduce the proliferation and stemness of the co-culture system, and decrease the expression of TGF-β and IL-6.

Conclusions

These results suggested that co-culturing A549 cells with THP-1-derived macrophages could induce the stemness of A549 cells via multiple pro-tumorigenic pathways. Thus, inhibition of the interaction between macrophages and lung cancer stem cells may be a viable target for lung cancer treatment in the future.

Nanog maintains stemness of Lkb1-deficient lung adenocarcinoma and prevents gastric differentiation

Growing evidence supports that LKB1-deficient KRAS-driven lung tumors represent a unique therapeutic challenge, displaying strong cancer plasticity that promotes lineage conversion and drug resistance. Here we find that murine lung tumors from the KrasLSL-G12D/+ ; Lkb1flox/flox (KL) model show strong plasticity, which associates with up-regulation of stem cell pluripotency genes such as Nanog. Deletion of Nanog in KL model initiates a gastric differentiation program and promotes mucinous lung tumor growth. We find that NANOG is not expressed at a meaningful level in human lung adenocarcinoma (ADC), as well as in human lung invasive mucinous adenocarcinoma (IMA). Gastric differentiation involves activation of Notch signaling, and perturbation of Notch pathway by the γ-secretase inhibitor LY-411575 remarkably impairs mucinous tumor formation. In contrast to non-mucinous tumors, mucinous tumors are resistant to phenformin treatment. Such therapeutic resistance could be overcome through combined treatments with LY-411575 and phenformin. Overall, we uncover a previously unappreciated plasticity of LKB1-deficient tumors and identify the Nanog-Notch axis in regulating gastric differentiation, which holds important therapeutic implication for the treatment of mucinous lung cancer.

The vascular nature of lung-resident mesenchymal stem cells

Human lungs bear their own reservoir of endogenous mesenchymal stem cells (MSCs). Although described as located perivascular, the cellular identity of primary lung MSCs remains elusive. Here we investigated the vascular nature of lung‐resident MSCs (LR‐MSCs) using healthy human lung tissue. LR‐MSCs predominately reside within the vascular stem cell niche, the so‐called vasculogenic zone of adult lung arteries. Primary LR‐MSCs isolated from normal human lung tissue showed typical MSC characteristics in vitro and were phenotypically and functionally indistinguishable from MSCs derived from the vascular wall of adult human blood vessels (VW‐MSCs). Moreover, LR‐MSCs expressed the VW‐MSC‐specific HOX code a characteristic to discriminate VW‐MSCs from phenotypical similar cells. Thus, LR‐MSC should be considered as VW‐MSCs. Immunofluorescent analyses of non‐small lung cancer (NSCLC) specimen further confirmed the vascular adventitia as stem cell niche for LR‐MSCs, and revealed their mobilization and activation in NSCLC progression. These findings have implications for understanding the role of MSC in normal lung physiology and pulmonary diseases, as well as for the rational design of additional therapeutic approaches.

Targeting lung cancer stem cells using combination of Tel and Docetaxel liposomes in 3D cultures and tumor xenografts

Cancer stem cells (CSCs) accounts for recurrence and resistance to chemotherapy in various tumors. Efficacy of chemotherapeutic drugs is limited by tumor stromal barriers, which hinder their penetration into deep tumor sites. We have earlier shown telmisartan (Tel) pretreatment prior to Docetaxel (DTX) administration enhances anti-cancer effects in non-small cell lung cancer (NSCLC). Herein, we demonstrated for the first time the efficacy of Docetaxel liposomes (DTXPL) in combination with Tel in 3D cultures of H460 cells by using polysaccharide-based hydrogels (TheWell Biosciences) and also in xenograft model of DTX resistant H460 derived CD133+ lung tumors. DTXPL and Tel combination showed enhanced cytotoxicity in H460 WT 3D cultures by two folds. In H460 3D cultures, Tel pretreatment showed increased liposomal uptake. DTXPL and Tel combination treated tumors showed reduction in tumor volume (p < .001), increased apoptosis and downregulation of CSC markers (p < .01) in H460 WT and DTX resistant CD133+ xenograft models.

Cancer Stem Cells-Origins and Biomarkers: Perspectives for Targeted Personalized Therapies

The use of biomarkers in diagnosis, therapy and prognosis has gained increasing interest over the last decades. In particular, the analysis of biomarkers in cancer patients within the pre- and post-therapeutic period is required to identify several types of cells, which carry a risk for a disease progression and subsequent post-therapeutic relapse. Cancer stem cells (CSCs) are a subpopulation of tumor cells that can drive tumor initiation and can cause relapses. At the time point of tumor initiation, CSCs originate from either differentiated cells or adult tissue resident stem cells. Due to their importance, several biomarkers that characterize CSCs have been identified and correlated to diagnosis, therapy and prognosis. However, CSCs have been shown to display a high plasticity, which changes their phenotypic and functional appearance. Such changes are induced by chemo- and radiotherapeutics as well as senescent tumor cells, which cause alterations in the tumor microenvironment. Induction of senescence causes tumor shrinkage by modulating an anti-tumorigenic environment in which tumor cells undergo growth arrest and immune cells are attracted. Besides these positive effects after therapy, senescence can also have negative effects displayed post-therapeutically. These unfavorable effects can directly promote cancer stemness by increasing CSC plasticity phenotypes, by activating stemness pathways in non-CSCs, as well as by promoting senescence escape and subsequent activation of stemness pathways. At the end, all these effects can lead to tumor relapse and metastasis. This review provides an overview of the most frequently used CSC markers and their implementation as biomarkers by focussing on deadliest solid (lung, stomach, liver, breast and colorectal cancers) and hematological (acute myeloid leukemia, chronic myeloid leukemia) cancers. Furthermore, it gives examples on how the CSC markers might be influenced by therapeutics, such as chemo- and radiotherapy, and the tumor microenvironment. It points out, that it is crucial to identify and monitor residual CSCs, senescent tumor cells, and the pro-tumorigenic senescence-associated secretory phenotype in a therapy follow-up using specific biomarkers. As a future perspective, a targeted immune-mediated strategy using chimeric antigen receptor based approaches for the removal of remaining chemotherapy-resistant cells as well as CSCs in a personalized therapeutic approach are discussed.

Prognostic Significance of the Pluripotency Factors NANOG, SOX2, and OCT4 in Head and Neck Squamous Cell Carcinomas

Cancer stem cells (CSCs) play major roles in tumor initiation, progression, and resistance to cancer therapy. Several CSC markers have been studied in head and neck squamous cell carcinomas (HNSCC), including the pluripotency factors NANOG, SOX2, and OCT4; however, their clinical significance is still unclear. NANOG, SOX2, and OCT4 expression was evaluated by immunochemistry in 348 surgically-treated HNSCC, and correlated with clinicopathological parameters and patient outcomes. mRNA expression was further analyzed in 530 The Cancer Genome Atlas (TCGA) HNSCC. NANOG protein expression was detected in 250 (72%) cases, more frequently in patients with lymph node metastasis (p = 0.003), and was an independent predictor of better survival in multivariate analysis. While OCT4 expression was undetectable, SOX2 expression was observed in 105 (30%) cases, and strongly correlated with NANOG expression. Combined expression of both proteins showed the highest survival rates, and double-negative cases the worst survival. Strikingly, the impact of NANOG and SOX2 on outcome varied depending on tumor site and lymph node infiltration, specifically showing prognostic significance in pharyngeal tumors. Correlation between NANOG and SOX2 at mRNA and protein was specifically observed in node positive (N+) patients, and consistently correlated with better survival rates. According to our findings, NANOG protein expression is frequent in HNSCC, thereby emerging as an independent predictor of better prognosis in pharyngeal tumors. Moreover, this study uncovers a differential impact of NANOG and SOX2 expression on HNSCC prognosis, depending on tumor site and lymph node infiltration, which could facilitate high-risk patient stratification.

NANOG expression in human development and cancerogenesis

NANOG is an important stem cell transcription factor involved in human development and cancerogenesis. Its expression is complex and regulated on different levels. Moreover, NANOG protein might regulate hundreds of target genes at the same time. NANOG is crucial for preimplantation development phase and progressively decreases during embryonic stem cells differentiation, thus regulating embryonic and fetal development. Postnatally, NANOG is undetectable or expressed in very low amounts in the majority of human tissues. NANOG re-expression can be detected during cancerogenesis, already in precancerous lesions, with increasing levels of NANOG in high grade dysplasia. NANOG is believed to enable cancer cells to obtain stem-cell like properties, which are believed to be the source of expanding growth, tumor maintenance, metastasis formation, and tumor relapse. High NANOG expression in cancer is frequently associated with advanced stage, poor differentiation, worse overall survival, and resistance to treatment, and is therefore a promising prognostic and predictive marker. We summarize the current knowledge on the role of NANOG in cancerogenesis and development, including our own experience. We provide a critical overview of NANOG as a prognostic and diagnostic factor, including problems regarding its regulation and detection.

Isolation and Identification of Cancer Stem-Like Cells in Adenocarcinoma and Squamous Cell Carcinoma of the Lung: A Pilot Study

Background: Lung cancer stem cells (CSCs) share many characteristics with normal stem cells, such as self-renewal and multipotentiality. High expression of aldehyde dehydrogenase (ALDH) has been detected in many tumors, particularly in the CSC compartment, and it plays an important role in tumor proliferation, metastasis, and drug resistance. CD44 is commonly used as a cell surface marker of cancer stem-like cells in epithelial tumors. The aim of this study was to isolate and analyze cancer stem-like cells from surgically removed specimens to compare lung adenocarcinoma (ADENO) and squamous (SQUAMO) cell carcinoma. Methods: The ALDEFLUOR assay was used to identify and sort ALDH^high and ALDH^low human lung cancer cells following tissue digestion. Fluorescence-activated cell sorting analysis for CD44 was performed with tumor cells. Quantitative real-time PCR was performed to assess the expression of SOX2 and NANOG as stemness markers. ALDH1A1 expression was additionally determined by immunohistochemistry. Anchorage-independent ALDH^high cell growth was also evaluated. ALDH^high ADENO and SQUAMO cells were cultured to analyze spheroid formation. Results: All specimens contained 0.5-12.5% ALDH^high cells with 3.8-18.9% CD44-positive cells. SOX2 and NANOG relative expression in ALDH^high compared to ALDH^low cells in ADENO and SQUAMO was analyzed and compared between the histotypes. Immunohistochemistry confirmed the presence of ALDH1A1 in the sections. SOX2 and NANOG were expressed at higher levels in the ALDH^high subpopulation than in the ALDH^low subpopulation only in ADENO cells, and the opposite result was seen in SQUAMO cells. In vitro functional assays demonstrated that ALDH^high cells exhibited migration capacity with distinct behaviors between ALDH^high spheres in ADENO vs. SQUAMO samples. Conclusions: Our results highlight the importance of a better characterization of cancer stem-like cells in ADENO and SQUAMO histotypes. This may suggest new differential approaches for prognostic and therapeutic purposes in patients with non-small-cell lung cancer.

Lung tumorspheres reveal cancer stem cell-like properties and a score with prognostic impact in resected non-small-cell lung cancer

The high resistance against current therapies found in non-small-cell lung cancer (NSCLC) has been associated to cancer stem-like cells (CSCs), a population for which the identification of targets and biomarkers is still under development. In this study, primary cultures from early-stage NSCLC patients were established, using sphere-forming assays for CSC enrichment and adherent conditions for the control counterparts. Patient-derived tumorspheres showed self-renewal and unlimited exponential growth potentials, resistance against chemotherapeutic agents, invasion and differentiation capacities in vitro, and superior tumorigenic potential in vivo. Using quantitative PCR, gene expression profiles were analyzed and NANOG, NOTCH3, CD44, CDKN1A, SNAI1, and ITGA6 were selected to distinguish tumorspheres from adherent cells. Immunoblot and immunofluorescence analyses confirmed that proteins encoded by these genes were consistently increased in tumorspheres from adenocarcinoma patients and showed differential localization and expression patterns. The prognostic role of genes significantly overexpressed in tumorspheres was evaluated in a NSCLC cohort (N = 661) from The Cancer Genome Atlas. Based on a Cox regression analysis, CDKN1A, SNAI1, and ITGA6 were found to be associated with prognosis and used to calculate a gene expression score, named CSC score. Kaplan–Meier survival analysis showed that patients with high CSC score have shorter overall survival (OS) in the entire cohort [37.7 vs. 60.4 months (mo), p = 0.001] and the adenocarcinoma subcohort [36.6 vs. 53.5 mo, p = 0.003], but not in the squamous cell carcinoma one. Multivariate analysis indicated that this gene expression score is an independent biomarker of prognosis for OS in both the entire cohort [hazard ratio (HR): 1.498; 95% confidence interval (CI), 1.167–1.922; p = 0.001] and the adenocarcinoma subcohort [HR: 1.869; 95% CI, 1.275–2.738; p = 0.001]. This score was also analyzed in an independent cohort of 114 adenocarcinoma patients, confirming its prognostic value [42.90 vs. not reached (NR) mo, p = 0.020]. In conclusion, our findings provide relevant prognostic information for lung adenocarcinoma patients and the basis for developing novel therapies. Further studies are required to identify suitable markers and targets for lung squamous cell carcinoma patients.

Acquisition of Cancer Stem Cell-like Properties in Human Small Airway Epithelial Cells after a Long-term Exposure to Carbon Nanomaterials

Cancer stem cells (CSCs) are a key driver of tumor formation and metastasis, but how they are affected by nanomaterials is largely unknown. The present study investigated the effects of different carbon-based nanomaterials (CNMs) on neoplastic and CSC-like transformation of human small airway epithelial cells and determined the underlying mechanisms. Using a physiologically relevant exposure model (long-term/low-dose) with system validation using a human carcinogen, asbestos, we demonstrated that single-walled carbon nanotubes, multi-walled carbon nanotubes, ultrafine carbon black, and crocidolite asbestos induced particle-specific anchorage-independent colony formation, DNA-strand break, and p53 downregulation, indicating genotoxicity and carcinogenic potential of CNMs. The chronic CNM-exposed cells exhibited CSC-like properties as indicated by 3D spheroid formation, anoikis resistance, and CSC markers expression. Mechanistic studies revealed specific self-renewal and epithelial-mesenchymal transition (EMT)-related transcription factors that are involved in the cellular transformation process. Pathway analysis of gene signaling networks supports the role of SOX2 and SNAI1 signaling in CNM-mediated transformation. These findings support the potential carcinogenicity of high aspect ratio CNMs and identified molecular targets and signaling pathways that may contribute to the disease development.

ALDH1 expression correlates with an epithelial-like phenotype and favorable prognosis in lung adenocarcinoma: a study based on immunohistochemistry and mRNA expression data

PURPOSE

Cancer stem cells (CSC) and epithelial-mesenchymal transition (EMT) pathways are crucial for cancer progression. However, synergistic interactions between CSC and EMT are not clear in non-small cell lung cancer (NSCLC). The objective of this study was to investigate CSC markers such as CD44, NANOG, and ALDH1 expression and its correlation with EMT markers in NSCLC patients. Its association with survival was also determined.

METHODS

CD44, NANOG, and ALDH1 protein expression was evaluated in 267 resected NSCLC and its correlation with e-cadherin, β-catenin, p120 catenin, vimentin, SNAIL, and TWIST expressions was determined based on immunohistochemical and mRNA expression data from The Cancer Genome Atlas (TCGA) database. Survival analyses also were performed based on immunohistochemistry and mRNA expression data from Gene Expression Omnibus dataset.

RESULTS

ALDH1 expression in lung adenocarcinoma was positively correlated with the epithelial-like phenotype, low vimentin and low TWIST in immunohistochemical and mRNA expression data. NANOG and ALDH1 expressions measured by immunohistochemical and mRNA expression profiling data of adenocarcinomas were associated with a favorable prognosis. ALDH1 was an independent favorable prognostic marker for overall survival or recurrence-free survival in adenocarcinoma (P = 0.026 and P = 0.033, respectively). The epithelial-like phenotype expressing P120-catenin and beta-catenin was associated with a favorable prognosis; however, the TWIST-expressing mesenchymal-like phenotype was correlated with an unfavorable prognosis.

CONCLUSIONS

NANOG and ALDH1 protein or mRNA expression showed improved prognosis in adenocarcinoma alone. ALDH1 expression correlated with an epithelial-like phenotype.

Clinicopathological and prognostic significance of Nanog expression in non-small cell lung cancer: a meta-analysis

Background: Nanog has been found to be overexpressed in various cancers. However, the association between Nanog expression and prognosis or clinicopathological features is still controversial. Therefore, this meta-analysis was conducted to identify whether Nanog expression was associated with prognosis or clinicopathological characteristics in non-small cell lung cancer (NSCLC). Methods: We searched Embase, PubMed, Web of Science, the Cochrane Library, the Chinese National Knowledge Infrastructure database (CNKI), and the Wanfang database for articles. Pooled hazard ratios (HR), odds ratios (OR), and corresponding 95% confidence intervals (CI) were utilized to evaluate the relationship between Nanog expression and prognosis or clinicopathological characteristics in NSCLC. Results: The results showed that high expression of Nanog was significantly associated with poor overall survival (OS) (HR=1.95, 95% CI: 1.38-2.75, P=0.000). Additionally, high Nanog expression was significantly correlated with tumor differentiation (OR=3.18, 95% CI: 1.69-5.98, P=0.000) and TNM stage (OR=1.78, 95% CI: 1.28-2.47, P=0.001). However, no significant relationship was observed between Nanog expression and other clinicopathological features, including gender (OR=0.95, 95% CI: 0.69-1.33, P=0.783), age (OR=0.78, 95% CI: 0.57-1.07, P=0.119), tumor size (OR=0.87, 95% CI: 0.26-2.95, P=0.824), and lymph node metastasis (OR=1.29, 95% CI: 0.94-1.77, P=0.121). Conclusion: High Nanog expression was associated with poor prognosis in patients with NSCLC, and Nanog may serve as a prognostic predictor in NSCLC.

The Prognostic and Clinicopathologic Characteristics of OCT4 and Lung Cancer: A Meta-Analysis

Objective:

The relationship between OCT4 and clinicopathological features in lung cancer is shown to be controversial in recent publications. Therefore, we conducted this meta-analysis to quantitatively investigate the prognostic and clinicopathological characteristics of OCT4 in lung cancer.

Methods:

A comprehensive literature search of the PubMed, EMBASE, Cochrane Library, WOS, CNKI and Wanfang databases was performed to identify studies. Correlations between OCT4 expression and survival outcomes or clinicopathological features were analyzed using meta-analysis methods.

Results:

Twenty-one studies with 2523 patients were included. High OCT4 expression showed a poorer overall survival (OS) (univariate: HR= 2.00, 95% CI = (1.68, 2.39), p<0.0001; multivariate: HR= 2.43, 95% CI = (1.67, 3.55), p<0.0001) and median overall survival (MSR = 0.51, 95% CI = (0.44, 0.58), p < 0.0001), disease-free survival (DFS) (HR= 2.18, 95% CI = (1.30, 3.67), p = 0.003) and poorer disease-specific survival (DSS) (HR= 2.23, 95% CI = (1.21, 4.11), p = 0.010). Furthermore, high OCT4 expression was found to be related with lower 5 year disease-specific survival rate (OR= 0.24, 95% CI = (0.14, 0.41), p<0.0001) and 10 year overall survival rate (OR= 0.22, 95% CI = (0.12, 0.40), p=0.0001). Additionally, OCT4-high expression was also strongly associated with higher clinical TNM stage, lymph node metastasis, tumor distant metastasis, higher histopathologic grade, but not related with gender, smoking status, tumor size and histologic type of lung cancer.

Conclusion:

OCT4 over-expression in lung cancer was strongly related to poorer clinicopathological features and worse survival outcomes, which suggests that OCT4 could be a valuable prognostic marker in lung cancer.

The Prognostic Value of Nanog Overexpression in Lung Cancer: A Meta-Analysis

BACKGROUND

Recent several studies have showed that the nanog overexpression leads to poor prognosis in some kinds of cancer including hepatocellular carcinoma and gastrointestinal luminal cancer. However, the correlations between prognosis and clinic-pathological features and nanog overexpression in lung cancer are still not well-known. Thus, we performed a meta-analysis to evaluate the role of nanog in lung cancer.

METHODS

An electronic retrieval for related studies was conducted in PubMed, Cochrane Library, Web of Science, EMBASE databases, Chinese CNKI, and the Chinese Wan Fang database up to May 2018. The relationships between nanog overexpression and overall survival (OS) and disease-free survival (DFS) as well as clinic-pathological features in lung cancer were investigated. Pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by STATA12.

RESULTS

11 studies containing 1422 patients were identified in our meta-analysis. The overexpression of nanog showed decreased OS (HR = 1.83, 95% CI = 1.49-2.25, P ≤ 0.001) and DFS (HR = 1.86, 95% CI = 1.2-2.9, P = 0.006). Moreover, overexpression of nanog was significantly related to differentiation (OR = 4.17, 95% CI = 2.17-6.43, P ≤ 0.001), lymph node metastasis (OR = 1.76, 95% CI = 1.06-2.91, P = 0.028) and tumor size (OR = 1.93, 95% CI = 1.17-3.20, P = 0.010), and no correlation with T stage, TNM, stage, and gender.

CONCLUSIONS

Our results suggested that nanog overexpression, a hazard factor of differentiation, lymph node metastasis, and tumor size, may predicate decreased OS and DFS for lung cancer.

NEAT1 contributes to the CSC-like traits of A549/CDDP cells via activating Wnt signaling pathway

Long non-coding RNAs (lncRNAs) have been identified to exert crucial roles in tumorigenesis and can serve as novel biomarkers for cancer therapy including lung cancer. Cisplatin is a first-line chemotherapeutic agent in non-small cell lung cancer (NSCLC), but the therapeutic effect is unsatisfactory, partly due to drug resistance. Emerging evidence showed that chemo-resistance is associated with acquisition of cancer stem cell (CSC)-like properties. Cisplatin resistance remains a major obstacle in the treatment of lung cancer, and its mechanism is still not fully elucidated. Meanwhile, CSCs have been involved in tumor metastasis, tumor recurrence and chemotherapy resistance. So far, the mechanism of nuclear enriched abundant transcript 1 (NEAT1) in modulating CSCs in lung cancer remains barely known. Therefore, we aimed to explore the correlation between NEAT1 and cancer stem cells in lung cancer. In our current study, we observed that CSC-like traits were much more enriched in cisplatin-resistant A549/CDDP cells. In addition, NEAT1 was obviously up-regulated in A549/CDDP cells compared with parental A549 cells. Knockdown of NEAT1 decreased the CSC-like properties of A549/CDDP cells through inhibiting tumor cell sphere volume, repressing CSC-like biomarkers levels and restraining CD44 positive cell ratios. Oppositely, overexpression of NEAT1 enhanced the stemness respectively. Moreover, it has been reported that Wnt pathway is implicated in many vital cellular functions including cancer stem cells. Here, it was exhibited that Wnt signal pathway was inactivated by knockdown of NEAT1 whereas activated by NEAT1 overexpression in A549/CDDP cells. Taken these together, it was indicated that NEAT1 could exert a novel biological role in NSCLC chemo-resistance.

Prognostic significance of NANOG expression in solid tumors: a meta-analysis

Purpose

NANOG is a tumor marker and indicates poor prognosis in various neoplasms; however, the evidence is controversial. This meta-analysis investigated the association of NANOG expression and clinicopathological features, and it impact on survival of patients with malignant tumors.

Methods

Studies published through May 31, 2018 were retrieved from PubMed, Web of Science, Embase, and the China National Knowledge Infrastructure. Two researchers independently screened the content and quality of studies and extracted data. Correlations of NANOG expression, clinicopathological variables, and survival were analyzed and the combined odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated.

Results

Thirty-three articles including 35 data sets of 3,959 patients were analyzed. Overall, elevated NANOG expression was associated with poor overall survival (HR = 2.19; 95% CI: 1.87–2.58, P<0.001) and poor disease-free survival (HR = 2.21, 95% CI: 1.54–3.18, P<0.001). Subgroup analysis found that NANOG expression was associated with worse overall survival in non–small cell lung (HR = 1.87; 95% CI: 1.26–2.76, P = 0.002), head and neck (HR = 2.29; 95% CI: 1.75–3.02, P<0.001), and digestive system (HR = 2.38; 95% CI: 1.95–2.91, P<0.001) cancers. Moreover, we found that high NANOG expression was associated with poor tumor differentiation (OR = 2.63; 95% CI: 1.59–4.55, P = 0.001), lymph node metastasis (OR = 2.59; 95% CI: 1.50–4.47, P = 0.001), advanced TNM stage (OR = 2.22; 95% CI: 1.42–3.45, P<0.001), and T stage (OR = 0.44; 95% CI: 0.20–0.93, P = 0.031).

Conclusion

The evidence supports NANOG as a tumor biomarker to guide clinical management and indicate prognosis. Additional studies are needed to further validate these results.

Prognostic role of snail in lung cancer: Protocol for a systematic review

BACKGROUND

Increasing studies were performed to explore the prognostic value of snail in lung cancer (LC), however, with inconsistent results. Hence, this systematic review is aimed to evaluate the prognostic role of snail in patients with LC.

METHODS

A comprehensive literature search in the PubMed, Embase, the Cochrane Library, and Web of Science databases will be conducted to identify eligible studies. Language is limited as English. We will employ hazard ratios (HRs) and 95% confidence intervals (95% CIs) to estimate the correlations between snail expression and overall survival (OS), progression-free survival (PFS), recurrence-free survival (RFS), disease-free survival (DFS), and clinicopathological features. Meta-analysis will be performed using STATA 14.0 software.

RESULTS

This study will provide a high-quality synthesis of current evidence of the correlations between snail expression and OS, PFS/RFS/DFS, and clinicopathological features.

CONCLUSION

The study will provide updated evidence to assess whether the expression of snail is in association with poor prognosis in patients with LC.

ETHICS AND DISSEMINATION

It is not necessary for ethical approval because individuals cannot be identified. The protocol will be disseminated in a peer-reviewed journal or presented at a relevant conference.

PROSPERO REGISTRATION NUMBER

This systematic review protocol has been registered in the PROSPERO network (No. CRD42018095191).

IL22 Promotes Kras-Mutant Lung Cancer by Induction of a Protumor Immune Response and Protection of Stemness Properties

Somatic KRAS mutations are the most common oncogenic variants in lung cancer and are associated with poor prognosis. Using a Kras-induced lung cancer mouse model, CC-LR, we previously showed a role for inflammation in lung tumorigenesis through activation of the NF-κB pathway, along with induction of interleukin 6 (IL6) and an IL17-producing CD4+ T-helper cell response. IL22 is an effector molecule secreted by CD4+ and γδ T cells that we previously found to be expressed in CC-LR mice. IL22 mostly signals through the STAT3 pathway and is thought to act exclusively on nonhematopoietic cells with basal IL22 receptor (IL22R) expression on epithelial cells. Here, we found that higher expression of IL22R1 in patients with KRAS-mutant lung adenocarcinoma was an independent indicator of poor recurrence-free survival. We then showed that genetic ablation of Il22 in CC-LR mice (CC-LR/IL22KO mice) caused a significant reduction in tumor number and size. This was accompanied by significantly lower tumor cell proliferation, angiogenesis, and STAT3 activation. Il22 ablation was also associated with significant reduction in lung-infiltrating inflammatory cells and expression of protumor inflammatory cytokines. Conversely, this was accompanied with increased antitumor Th1 and cytotoxic CD8+ T-cell responses, while suppressing the protumor immunosuppressive T regulatory cell response. In CC-LR/IL22KO mice, we found significantly reduced expression of core stemness genes and the number of prototypical SPC+CCSP+ stem cells. Thus, we conclude that IL22 promotes Kras-mutant lung tumorigenesis by driving a protumor inflammatory microenvironment with proliferative, angiogenic, and stemness contextual cues in epithelial/tumor cells. Cancer Immunol Res; 6(7); 788-97. ©2018 AACR.

Differences of tumor microenvironment between stage I lepidic-positive and lepidic-negative lung adenocarcinomas

OBJECTIVE

Lepidic growth is a noninvasive component of lung adenocarcinoma. Many adenocarcinoma cases contain coexistent lepidic and nonlepidic (invasive) components (lepidic-growth positive [Lep+] adenocarcinoma); however, some cases comprise only nonlepidic components (lepidic-growth negative [Lep-] adenocarcinoma). The aim of this study was to investigate the biological differences between the invasive components of Lep+ and Lep- adenocarcinoma.

METHODS

We investigated the clinicopathologic characteristics of 232 adenocarcinomas (116 size-matched tumor pairs from Lep+ and Lep- adenocarcinomas). We then evaluated the cancer cell-specific expression levels of cancer stem cell, hypoxia, and invasion molecules in these lesions. The number of tumor-promoting stromal cells, including podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor-associated macrophages, was also analyzed.

RESULTS

Among cases with size-matched invasive components, significant differences were shown in total tumor size and predominant subtype in invasive component between Lep+ and Lep- adenocarcinomas. The expression levels of hypoxia-related molecules were significantly lower in Lep+ adenocarcinomas (glucose transporter 1: 0 vs 10, P < .01; carbonic anhydrase IX: 0 vs 0 [mean, 4.7 vs 14.1], P = .01). The number of podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor-associated macrophages was significantly lower in Lep+ adenocarcinomas (podoplanin-positive cancer-associated fibroblasts: 0 vs 0 [mean: 1.6 vs 11.6], P < .01; CD204-positive tumor-associated macrophages: 8.7 vs 24.7, P < .01).

CONCLUSIONS

Our results indicated that lower cancer cell-specific expression levels of hypoxia markers and a smaller number of tumor-promoting stromal cells in invasive component were characteristic features of Lep+ adenocarcinomas.

Current perspectives on the crosstalk between lung cancer stem cells and cancer-associated fibroblasts

Lung cancer, in particular non-small cell lung carcinoma (NSCLC), is the second most common cancer in both men and women and the leading cause of cancer-related deaths worldwide. Its prognosis and diagnosis are determined by several driver mutations and diverse risk factors (e.g. smoking). While immunotherapy has proven effective in some patients, treatment of NSCLC using conventional chemotherapy is largely ineffective. The latter is believed to be due to the existence of a subpopulation of stem-like, highly tumorigenic and chemoresistant cells within the tumor population known as cancer stem cells (CSC). To complicate the situation, CSCs interact with the tumor microenvironment, which include cancer-associated fibroblasts (CAFs), immune cells, endothelial cells, growth factors, cytokines and connective tissue components, which via a dynamic crosstalk, composed of proteins and exosomes, activates the CSC compartment. In this review, we analyze the crosstalk between CSCs and CAFs, the primary component of the NSCLC microenvironment, at the molecular and extracellular level and contemplate therapies to disrupt this communication.

Interaction between the estrogen receptor and fibroblast growth factor receptor pathways in non-small cell lung cancer

The estrogen receptor (ER) promotes non-small cell lung cancer (NSCLC) proliferation. Since fibroblast growth factors (FGFs) are known regulators of stem cell markers in ER positive breast cancer, we investigated whether a link between the ER, FGFs, and stem cell markers exists in NSCLC. In lung preneoplasias and adenomas of tobacco carcinogen exposed mice, the anti-estrogen fulvestrant and/or the aromatase inhibitor anastrozole blocked FGF2 and FGF9 secretion, and reduced expression of the stem cell markers SOX2 and nanog. Mice administered β-estradiol during carcinogen exposure showed increased FGF2, FGF9, SOX2, and Nanog expression in airway preneoplasias. In normal FGFR1 copy number NSCLC cell lines, multiple FGFR receptors were expressed and secreted several FGFs. β-estradiol caused enhanced FGF2 release, which was blocked by fulvestrant. Upon co-inhibition of ER and FGFRs using fulvestrant and the pan-FGFR inhibitor AZD4547, phosphorylation of FRS2, the FGFR docking protein, was maximally reduced, and enhanced anti-proliferative effects were observed. Combined AZD4547 and fulvestrant enhanced lung tumor xenograft growth inhibition and decreased Ki67 and stem cell marker expression. To verify a link between ERβ, the predominant ER in NSCLC, and FGFR signaling in patient tumors, mRNA analysis was performed comparing high versus low ERβ expressing tumors. The top differentially expressed genes in high ERβ tumors involved FGF signaling and human embryonic stem cell pluripotency. These results suggest interaction between the ER and FGFR pathways in NSCLC promotes a stem-like state. Combined FGFR and ER inhibition may increase the efficacy of FGFR inhibitors for NSCLC patients lacking FGFR genetic alterations.

[Impact of Cystic Fibrosis Transmembrane Conductance Regulator on Malignant Properties of KRAS Mutant Lung Adenocarcinoma A549 Cells]

背景与目的

肺癌发病率逐年上升，有必要寻找新型的治疗靶点，而最新研究发现囊状纤维化跨膜转导调节子（cystic fibrosis transmembrane conductance regulator, CFTR）与多种肿瘤的发生和恶性转化有关。本研究探讨CFTR对肺癌A549细胞恶性特性的影响。

方法

应用CCK8细胞增殖实验、细胞划痕实验、Transwell细胞侵袭实验以及克隆形成实验等方法分别检测CFTR的表达对非小细胞肺癌A549细胞的增殖、迁移、侵袭等细胞恶性特性的影响。同时通过免疫印迹（Western blot）分析CFTR基因表达对肿瘤干细胞相关转录因子表达的影响。

结果

过表达CFTR基因显著抑制A549细胞的增殖、迁移、侵袭和克隆形成等肿瘤恶性特征，而RNA干扰A549细胞CFTR的表达导致细胞上述特征的明显增强。免疫印迹实验进一步发现CFTR基因过表达抑制A549细胞中干细胞相关转录因子SOX2和OCT3/4，以及细胞表面CD133蛋白的表达；相反，RNA干扰A549细胞中CFTR基因的表达增加SOX2、OCT4和CD133的表达。然而，免疫印迹和流式细胞术发现CFTR基因表达对A549细胞肺癌干细胞标志乙醛脱氢酶1的表达和阳性细胞数量无显著影响。

结论

CFTR基因在肺癌A549细胞中具有抑制细胞恶性特征的作用，提示其可能是肺腺癌治疗的一个新的靶点，但其对其他肺腺癌细胞的作用与分子机制还有待进一步研究。

SPC25 upregulation increases cancer stem cell properties in non-small cell lung adenocarcinoma cells and independently predicts poor survival

In this study, we investigated the functional role and prognostic value of spindle pole body component 25 (SPC25) in non-small cell lung cancer (NSCLC). SPC25 expression profile in lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC) and normal lung tissues was examined by using data from the Cancer Genome Atlas (TCGA) and the Human Protein Atlas (HPA). LUAD A549 cells and LUSC H520 cells were used to investigate the influence of SPC25 on cancer stem cell (CSC) properties in terms of the proportion of CD133⁺ cells, tumorsphere formation and CSC markers, including CD133, ALDH1 and Sox2. Data mining was also performed in the Kaplan-Meier plotter and TCGA-NSCLC to assess the independent prognostic value of SPC25. Results showed SPC25 was significantly upregulated in LUAD and LUSC tissues compared with normal lung tissues. SPC25 overexpression significantly increased the CSC properties and invasion of A549 cells, but not H520 cells. In comparison, SPC25 knockdown impaired the CSC properties and invasion of A549 cells, but not H520 cells. Univariate and multivariate analysis confirmed that high SPC25 expression was an independent prognostic factor for poor overall survival (OS) (HR: 1.622, 95%CI: 1.207-2.178, p = .001) and recurrence-free survival (RFS) (HR: 1.726, 95%CI: 1.242-2.399, p = .001) in LUAD patients. However, no independent prognostic value of SPC25 was observed in LUSC patients even under the best cut-off model. Based on these findings, we infer that SPC25 upregulation can increase CSC properties in LUAD and independently predict poor survival in this histological subtype.

Clinicopathological and prognostic significance of Twist overexpression in NSCLC

Several studies were conducted to explore the prognostic significance of Twist in non-small cell lung cancer (NSCLC), however, contradictory results in different studies were reported. To this end, we presented a systematic review aiming to summarize the prognostic significance of Twist in patients with NSCLC. 5 studies involving a total of 572 patients were identified. The result indicated that high Twist expression was significantly associated with a worse overall survival (OS) (hazard ratio (HR) = 2.19, 95% confidence interval (95% CI) = 1.64–2.94, p < 0.001; I² = 0.0%, fixed effect), recurrence-free survival (RFS) (HR = 2.476, 95% CI = 1.728–3.547, p < 0.001; I² = 0.0%, fixed effect) and lymph node or other metastasis (odds rate (OR) = 0.419, 95% CI = 0.259–0.679, P < 0.001, fixed effect). Subgroup analysis revealed that the expression of Twist in Chinese patients might be more closely associated with the prognosis of NSCLC than in American patients. Overall, these results indicated that Twist over-expression in patients with NSCLC might be related to poor prognosis and serves as an unfavorable predictor of poor clinicopathological prognosis factor.

Bone marrow-derived fibrocytes promote stem cell-like properties of lung cancer cells

Cancer stem cells (CSCs) represent a minor population that have clonal tumor initiation and self-renewal capacity and are responsible for tumor initiation, metastasis, and therapeutic resistance. CSCs reside in niches, which are composed of diverse types of stromal cells and extracellular matrix components. These stromal cells regulate CSC-like properties by providing secreted factors or by physical contact. Fibrocytes are differentiated from bone marrow-derived CD14⁺ monocytes and have features of both macrophages and fibroblasts. Accumulating evidence has suggested that stromal fibrocytes might promote cancer progression. However, the role of fibrocytes in the CSC niches has not been revealed. We herein report that human fibrocytes enhanced the CSC-like properties of lung cancer cells through secreted factors, including osteopontin, CC-chemokine ligand 18, and plasminogen activator inhibitor-1. The PIK3K/AKT pathway was critical for fibrocytes to mediate the CSC-like functions of lung cancer cells. In human lung cancer specimens, the number of tumor-infiltrated fibrocytes was correlated with high expression of CSC-associated protein in cancer cells. These results suggest that fibrocytes may be a novel cell population that regulates the CSC-like properties of lung cancer cells in the CSC niches.

FOXM1 activates AGR2 and causes progression of lung adenomas into invasive mucinous adenocarcinomas

Lung cancer remains one of the most prominent public health challenges, accounting for the highest incidence and mortality among all human cancers. While pulmonary invasive mucinous adenocarcinoma (PIMA) is one of the most aggressive types of non-small cell lung cancer, transcriptional drivers of PIMA remain poorly understood. In the present study, we found that Forkhead box M1 transcription factor (FOXM1) is highly expressed in human PIMAs and associated with increased extracellular mucin deposition and the loss of NKX2.1. To examine consequences of FOXM1 expression in tumor cells in vivo, we employed an inducible, transgenic mouse model to express an activated FOXM1 transcript in urethane-induced benign lung adenomas. FOXM1 accelerated tumor growth, induced progression from benign adenomas to invasive, metastatic adenocarcinomas, and induced SOX2, a marker of poorly differentiated tumor cells. Adenocarcinomas in FOXM1 transgenic mice expressed increased MUC5B and MUC5AC, and reduced NKX2.1, which are characteristics of mucinous adenocarcinomas. Expression of FOXM1 in KrasG12D transgenic mice increased the mucinous phenotype in KrasG12D-driven lung tumors. Anterior Gradient 2 (AGR2), an oncogene critical for intracellular processing and packaging of mucins, was increased in mouse and human PIMAs and was associated with FOXM1. FOXM1 directly bound to and transcriptionally activated human AGR2 gene promoter via the -257/-247 bp region. Finally, using orthotopic xenografts we demonstrated that inhibition of either FOXM1 or AGR2 in human PIMAs inhibited mucinous characteristics, and reduced tumor growth and invasion. Altogether, FOXM1 is necessary and sufficient to induce mucinous phenotypes in lung tumor cells in vivo.

PD-L1 immunohistochemical assays for assessment of therapeutic strategies involving immune checkpoint inhibitors in non-small cell lung cancer: a comparative study

Although immune checkpoints inhibitors have exhibited promising activity in clinical trials in non-small cell lung cancer (NSCLC) patients, the current programmed cell death-ligand 1 (PD-L1) assays are inconsistent in terms of the staining analysis and scoring system used. To verify the interchangeability of the available PD-L1 assays, we performed immunohistochemistry using three antibody clones used in clinical trials (22C3, SP263, and SP142) and the E1L3N clone as a laboratory developed test for 97 resected NSCLC specimens. Matched tissue microarray specimens were also stained. Staining with 22C3 yielded a greater proportion of stained tumor cells, whereas SP142 staining consistently labelled fewer tumor cells. However, when various cut-off criteria were applied, the positivity rates for PD-L1 were similar, with high concordance, under assay-specific cut-offs. Moreover, seven cases of discordant PD-L1 expression between the resected specimen and matched tissue microarray specimens were observed. In conclusion, despite of inter-assay variability of the PD-L1 status in NSCLC, the positivity rate appears to be similar under assay-specific criteria. Hence, an appropriate clinically defined algorithm or cut-off should be separately applied for each assay. Moreover, multiple biopsy specimens from different tumor areas should be obtained to reduce false results due to intratumoral heterogeneity in PD-L1 expression.

NANOG as an adverse predictive marker in advanced non-small cell lung cancer treated with platinum-based chemotherapy

Purpose

NANOG is a master transcription factor that regulates stem cell pluripotency and cellular reprograming. Increased NANOG expression has been associated with poor survival in several human malignancies. However, the clinical significance of NANOG overexpression in lung cancer has been scarcely evaluated. The aim of this study was to investigate whether NANOG levels are associated with clinical outcomes of patients with non–small cell lung cancer (NSCLC) who were treated with platinum-based chemotherapy.

Methods

NANOG levels were evaluated immunohistochemically using the histologic score (H-score) in tumor tissues from patients with advanced NSCLC who received platinum-based doublet treatment. We performed survival analyses according to the NANOG levels and evaluated the association between clinicopathological parameters and levels of NANOG.

Results

Multivariate analyses using 112 tumor specimens showed that high NANOG levels were independently associated with short progression-free survival (hazard ratio [HR] =3.09, 95% confidence interval [CI]: 2.01–4.76) and with short overall survival (HR =3.00, 95% CI: 1.98–4.54). Similar results were shown in the subgroup analyses for patients with adenocarcinoma and squamous cell carcinoma. NANOG expression was not associated with any clinicopathological parameter such as age, gender, smoking status, stage, differentiation, or histological subtypes.

Conclusion

NANOG overexpression was associated with poor response and short overall survival in patients with advanced NSCLC who were treated with platinum-based chemotherapy, suggesting that NANOG could be a potential adverse predictive marker in this setting.

A Novel Role For Nanog As An Early Cancer Risk Marker In Patients With Laryngeal Precancerous Lesions

NANOG is a master regulator of embryonic stem cell pluripotency, found to be frequently aberrantly expressed in a variety of cancers, including laryngeal carcinomas. This study investigates for the first time the role of NANOG expression in early stages of laryngeal tumourigenesis and its potential utility as cancer risk marker. NANOG protein expression was evaluated by immunohistochemistry using two large independent cohorts of patients with laryngeal precancerous lesions, and correlated with clinicopathological parameters and laryngeal cancer risk. NANOG expression was detected by immunohistochemistry in 49 (60%) of 82 laryngeal dysplasias, whereas expression was negligible in patient-matched normal epithelia. Strong NANOG expression was found in 22 (27%) lesions and was established as cut-off point, showing the most robust association with laryngeal cancer risk (P = 0.003) superior to the histological classification (P = 0.320) the current gold standard in the clinical practice. Similar trends were obtained using a multicenter validation cohort of 86 patients with laryngeal dysplasia. Our findings uncover a novel role for NANOG expression in laryngeal tumourigenesis, and its unprecedented application as biomarker for cancer risk assessment.

Blockade of Stearoyl-CoA-desaturase 1 activity reverts resistance to cisplatin in lung cancer stem cells

Poor prognosis in lung cancer has been attributed to the presence of lung cancer stem cells (CSCs) which resist chemotherapy and cause disease recurrence. Hence, the strong need to identify mechanisms of chemoresistance and to develop new combination therapies. We have previously shown that Stearoyl-CoA-desaturase 1 (SCD1), the enzyme responsible for the conversion of saturated to monounsaturated fatty acids is upregulated in 3D lung cancer spheroids and is an upstream activator of key proliferation pathways β-catenin and YAP/TAZ. Here we first show that SCD1 expression, either alone or in combination with a variety of CSCs markers, correlates with poor prognosis in adenocarcinoma (ADC) of the lung. Treatment of lung ADC cell cultures with cisplatin enhances the formation of larger 3D tumor spheroids and upregulates CSCs markers. In contrast, co-treatment with cisplatin and the SCD1 inhibitor MF-438 reverts upregulation of CSCs markers, strongly synergizes in the inhibition of 3D spheroids formation and induces CSCs apoptosis. Mechanistically, SCD1 inhibition activates endoplasmic reticulum stress response and enhances autophagy. These data all together support the use of combination therapy with SCD1 inhibitors to achieve better control of lung cancer.

A potent indolylquinoline alleviates growth of human lung cancer cell tumorspheres

To fight cancer at its roots by targeting cancer stem cells is a promising approach for therapy. Previously, an indolylquinoline derivative, 3-((7-ethyl-1H-indol-3-yl)-methyl)-2-methylquinoline (EMMQ), was reported effectively inhibiting the growth of lung cancer cells through impairment of cellular mitochondria functions. To address more on drug efficiency, the study further exploited if EMMQ can impede the propagation of tumorspheres stemmed from non-small cell lung cancer cells. EMMQ inhibited proliferation of spheroids in culture. In animal models, administration of the drug attenuated the spheroid tumorigenicity. The activated apoptosis alleviated growth of xenograft tumors in immune-deficient mice as established by the enriched tumorspheres. More evidence suggested that the reduced stemness of the spheroid tumors is attributed to apoptotic death. The findings supported that EMMQ is an eligible approach to eradicate the minor but tumorigenic lung cancer tumorspheres.

Evaluation of Breast Cancer Stem Cells and Intratumor Stemness Heterogeneity in Triple-negative Breast Cancer as Prognostic Factors

Triple-negative breast cancer (TNBC) is a tumor subtype with aggressive behavior and poor clinical outcome for lacking effective therapies. Breast cancer stem cells (BCSCs) have been suggested to have tumor-initiating properties, but it remains unclear whether their presence contributes to the increased aggressiveness and poor prognosis of TNBC. Also, the breast cancers display frequent inter- and intra-tumor heterogeneity, which adds the complexity in diagnosis and predicting prognosis. Here we investigated the clinical relevance and prognostic value of the BCSC markers, CD44⁺/CD24^-, aldehyde dehydrogenase family 1 member A1 (ALDH1A1) and CD133 in 88 TNBC cases. We found that a few patients displayed spatial heterogeneity of the BCSC markers in expression, which was defined as intratumor stemness heterogeneity (ITSH) below. There was no significant correlation between any BCSC marker alone or ITSH and progression-free survival (PFS). Interestingly, the combined BCSC phenotype by CD44⁺/CD24^- and ALDH1A1 was significantly associated with worse PFS (P = 0.009). Further stratification analysis revealed that this combined BCSC phenotype was an independent prognostic factor for PFS in some subgroups. In conclusion, we demonstrated the existence of ITSH in TNBC and found that the ITSH as well as a single BCSC marker was not significantly associated with survival, whereas combing the analysis of BCSC markers could improve prognostic value. Our findings may lead to an improvement of prognostic indicators in TNBC.