Nanog, a novel prognostic marker for lung cancer

Deregulated transcription factors in the emerging cancer hallmarks

Cancer progression is a multifaceted process that entails several stages and demands the persistent expression or activation of transcription factors (TFs) to facilitate growth and survival. TFs are a cluster of proteins with DNA-binding domains that attach to promoter or enhancer DNA strands to start the transcription of genes by collaborating with RNA polymerase and other supporting proteins. They are generally acknowledged as the major regulatory molecules that coordinate biological homeostasis and the appropriate functioning of cellular components, subsequently contributing to human physiology. TFs proteins are crucial for controlling transcription during the embryonic stage and development, and the stability of different cell types depends on how they function in different cell types. The development and progression of cancer cells and tumors might be triggered by any anomaly in transcription factor function. It has long been acknowledged that cancer development is accompanied by the dysregulated activity of TF alterations which might result in faulty gene expression. Recent studies have suggested that dysregulated transcription factors play a major role in developing various human malignancies by altering and rewiring metabolic processes, modifying the immune response, and triggering oncogenic signaling cascades. This review emphasizes the interplay between TFs involved in metabolic and epigenetic reprogramming, evading immune attacks, cellular senescence, and the maintenance of cancer stemness in cancerous cells. The insights presented herein will facilitate the development of innovative therapeutic modalities to tackle the dysregulated transcription factors underlying cancer.

Targeting Nanog expression increased Cisplatin chemosensitivity and inhibited cell migration in Gastric cancer cells

Regardless of significant advances in cancer treatment, gastric cancer (GC) incidence rate is increasing worldwide. As one of the main transcription factors participating in stemness, Nanog plays a pivotal role in various aspects of tumorigenesis, metastasis, and chemosensitivity. Given that, the current research intended to evaluate the potential effects of Nanog suppression on the GC cell cisplatin chemosensitivity and in vitro tumorigenesis. First, bioinformatics analysis was performed to evaluate the effect of Nanog expression on GC patients' survival. The MKN-45 human GC cells were transfected with specific siRNA targeting Nanog and/or treated with Cisplatin. Then, to study cellular viability and apoptosis, MTT assay and Annexin V/PI staining were done, respectively. Also, the scratch assay was performed to investigate cell migration, and MKN-45 cell stemness was followed using colony formation assay. Western blotting and qRT-PCR were used for gene expression analysis. The findings demonstrated that siRNA-mediated Nanog silencing strongly increased MKN-45 cell sensitivity to Cisplatin through apoptosis induction. Also, Nanog suppression combined with Cisplatin resulted in the upregulation of the Caspase-3 and Bax/Bcl-2 ratio at mRNA levels and increased Caspase-3 activation. Moreover, reduced expression of Nanog, separately or combined with Cisplatin, inhibited MKN-45 cell migration by downregulating MMP2 mRNA and protein expression levels. The results also evidenced CD44 and SOX-2 downregulation aligned with a decreased rate of MKN-45 cell colony formation ability through treatments. Besides, Nanog downregulation significantly decreased MDR-1 mRNA expression. Taken together, the results of this study indicated that Nanog could be suggested as a promising target combined with Cisplatin-based GC therapies for reducing drug side effects and improving patients' outcomes.

Transcriptional factors targeting in cancer stem cells for tumor modulation

Cancer Stem Cells (CSCs) are now considered the primary "seeds" for the onset, development, metastasis, and recurrence of tumors. Despite therapeutic breakthroughs, cancer remains the leading cause of death worldwide. This is because the tumor microenvironment contains a key population of cells known as CSCs, which promote tumor aggression. CSCs are self-renewing cells that aid tumor recurrence by promoting tumor growth and persisting in patients after many traditional cancer treatments. According to reports, numerous transcription factors (TF) play a key role in maintaining CSC pluripotency and its self-renewal property. The understanding of the functions, structures, and interactional dynamics of these transcription factors with DNA has modified the hypothesis, paving the way for novel transcription factor-targeted therapies. These TFs, which are crucial and are required by cancer cells, play a vital function in the etiology of human cancer. Such CSC TFs will help with gene expression profiling, which provides crucial data for predicting the prognosis of patients. To overcome anti-cancer medication resistance and completely eradicate cancer, a potent therapy combining TFs-based CSC targets with traditional chemotherapy may be developed. In order to develop therapies that could eliminate CSCs, we here concentrated on the effect of TFs and other components of signalling pathways on cancer stemness.

Construction of a predictive model for immunotherapy efficacy in lung squamous cell carcinoma based on the degree of tumor-infiltrating immune cells and molecular typing

Background

To construct a predictive model of immunotherapy efficacy for patients with lung squamous cell carcinoma (LUSC) based on the degree of tumor-infiltrating immune cells (TIIC) in the tumor microenvironment (TME).

Methods

The data of 501 patients with LUSC in the TCGA database were used as a training set, and grouped using non-negative matrix factorization (NMF) based on the degree of TIIC assessed by single-sample gene set enrichment analysis (GSEA). Two data sets (GSE126044 and GSE135222) were used as validation sets. Genes screened for modeling by least absolute shrinkage and selection operator (LASSO) regression and used to construct a model based on immunophenotyping score (IPTS). RNA extraction and qPCR were performed to validate the prognostic value of IPTS in our independent LUSC cohort. The receiver operating characteristic (ROC) curve was constructed to determine the predictive value of the immune efficacy. Kaplan–Meier survival curve analysis was performed to evaluate the prognostic predictive ability. Correlation analysis and enrichment analysis were used to explore the potential mechanism of IPTS molecular typing involved in predicting the immunotherapy efficacy for patients with LUSC.

Results

The training set was divided into a low immune cell infiltration type (C1) and a high immune cell infiltration type (C2) by NMF typing, and the IPTS molecular typing based on the 17-gene model could replace the results of the NMF typing. The area under the ROC curve (AUC) was 0.82. In both validation sets, the IPTS of patients who responded to immunotherapy were significantly higher than those who did not respond to immunotherapy (P = 0.0032 and P = 0.0451), whereas the AUC was 0.95 (95% CI = 1.00–0.84) and 0.77 (95% CI = 0.58–0.96), respectively. In our independent cohort, we validated its ability to predict the response to cancer immunotherapy, for the AUC was 0.88 (95% CI = 1.00–0.66). GSEA suggested that the high IPTS group was mainly involved in immune-related signaling pathways.

Conclusions

IPTS molecular typing based on the degree of TIIC in the TME could well predict the efficacy of immunotherapy in patients with LUSC with a certain prognostic value.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03565-7.

Nanog, as a key cancer stem cell marker in tumor progression

Cancer stem cells (CSCs) are a small population of malignant cells that induce tumor onset and development. CSCs share similar features with normal stem cells in the case of self-renewal and differentiation. They also contribute to chemoresistance and metastasis of cancer cells, leading to therapeutic failure. To identify CSCs, multiple cell surface markers have been characterized, including Nanog, which is found at high levels in different cancers. Recent studies have revealed that Nanog upregulation has a substantial association with the advanced stages and poor prognosis of malignancies, playing a pivotal role through tumorigenesis of multiple human cancers, including leukemia, liver, colorectal, prostate, ovarian, lung, head and neck, brain, pancreatic, gastric and breast cancers. Nanog through different signaling pathways, like JAK/STAT and Wnt/β-catenin pathways, induces stemness, self-renewal, metastasis, invasiveness, and chemoresistance of cancer cells. Some of these signaling pathways are common in various types of cancers, but some have been found in one or two cancers. Therefore, this review aimed to focus on the function of Nanog in multiple cancers based on recent studies surveying the suitable approaches to target Nanog and inhibit CSCs residing in tumors to gain favorable results from cancer treatments.

siRNA-mediated silencing of Nanog reduces stemness properties and increases the sensitivity of HepG2 cells to cisplatin

Liver cancer is one of the most lethal cancers having worldwide prevalence. Despite significant progress in cancer therapy, liver cancer-induced mortality is very high. Nanog, as an essential transcription factor modulating cellular multipotency, causes tumor progression, drug resistance, and preserves stemness properties in various tumors such as liver cancer. Thus, this research was conducted to evaluate the impact of combination therapy of Nanog siRNA/cisplatin on the sensitivity of liver cancer cells to this drug. HepG2 cells were transfected with Nanog siRNA and treated with cisplatin, individually and in combination. Then, it was observed that in transfected HepG2 cells, Nanog expression was significantly reduced at mRNA level and also these cells were sensitized to cisplatin. In addition, to assess the impact of Nanog siRNA and cisplatin individually and in combination on cells' viability, migration capacity, apoptosis, and cell cycle progression, the MTT, wound healing, colony formation assay, Annexin V/PI staining, and flow cytometry assays were applied on HepG2 cells, respectively. Also, the quantitive Real-Time PCR was used to check the expression of stemness-associated genes (CD44, CD133, and Sox2), and apoptosis-related genes (caspase-3, 8, 9, BAX and Bcl2) after combination therapy. It is indicated that the combination of Nanog siRNA and cisplatin significantly reduced proliferation, migration, and colony formation ability, as well as increased apoptosis rate, and cell cycle arrest. Also, it is found that the combination of Nanog siRNA and cisplatin down-regulated the expression of stemness-associated genes and up-regulated apoptosis-related genes in HepG2 cells. Hence, it can be suggested that Nanog inhibition in combination with cisplatin is a potential therapeutic strategy for developing new therapeutic approaches for liver cancer.

Cell Populations Expressing Stemness-Associated Markers in Lung Adenocarcinoma

The stemness-associated markers OCT4, NANOG, SOX2, KLF4 and c-MYC are expressed in numerous cancer types suggesting the presence of cancer stem cells (CSCs). Immunohistochemical (IHC) staining performed on 12 lung adenocarcinoma (LA) tissue samples showed protein expression of OCT4, NANOG, SOX2, KLF4 and c-MYC, and the CSC marker CD44. In situ hybridization (ISH) performed on six of the LA tissue samples showed mRNA expression of OCT4, NANOG, SOX2, KLF4 and c-MYC. Immunofluorescence staining performed on three of the tissue samples showed co-expression of OCT4 and c-MYC with NANOG, SOX2 and KLF4 by tumor gland cells, and expression of OCT4 and c-MYC exclusively by cells within the stroma. RT-qPCR performed on five LA-derived primary cell lines showed mRNA expression of all the markers except SOX2. Western blotting performed on four LA-derived primary cell lines demonstrated protein expression of all the markers except SOX2 and NANOG. Initial tumorsphere assays performed on four LA-derived primary cell lines demonstrated 0–80% of tumorspheres surpassing the 50 µm threshold. The expression of the stemness-associated markers OCT4, SOX2, NANOG, KFL4 and c-MYC by LA at the mRNA and protein level, and the unique expression patterns suggest a putative presence of CSC subpopulations within LA, which may be a novel therapeutic target for this cancer. Further functional studies are required to investigate the possession of stemness traits.

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.

1,25-dihydroxyvitamin D3 signaling-induced decreases in IRX4 inhibits NANOG-mediated cancer stem-like properties and gefitinib resistance in NSCLC cells

Recent studies have demonstrated that acquisition of cancer stem-like properties plays an essential role in promoting epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) resistance in non-small cell lung cancer (NSCLC); however, how to regulate cancer stem-like properties and EGFR-TKI resistance is largely unclear. In this study, we discovered that increased iroquois-class homeodomain protein 4 (IRX4) was related to gefitinib resistance in NSCLC cells. Knockdown of IRX4 inhibited cell proliferation, sphere formation, and the expression of CD133, ALDH1A1, NANOG, Sox2 and Notch1, and the transcriptional activity of NANOG promoter. IRX4 overexpression increased the protein level of NANOG and CD133 in PC-9 cells. Combination of knocking-down IRX4 with gefitinib increased cell apoptosis and decreased cell viability and the expression of p-EGFR and NANOG in PC-9/GR cells. IRX4 knockdown in a PC-9/GR xenograft tumor model inhibited tumor progression and the expression of NANOG and CD133 more effectively than single treatment alone. Knockdown of NANOG inhibited the expression of CD133 and restored gefitinib cytotoxicity, and NANOG overexpression-induced cancer stem-like properties and gefitinib resistance could be obviously reversed by knocking-down IRX4. Further, we found that 1,25-dihydroxyvitamin D3 (1,25(OH)₂D₃) reduced obviously the expression of IRX4 and NANOG by inhibiting the activation of TGF-β1/Smad3 signaling pathway; moreover, combination of 1,25(OH)₂D₃ and gefitinib decreased cell viability and proliferation or tumor progression and the expression of IRX4 and NANOG compared with single treatment alone both in PC-9/GR cells and in a PC-9/GR xenograft tumor model. These results reveal that inhibition of IRX4-mediated cancer stem-like properties by regulating 1,25(OH)₂D₃ signaling may increase gefitinib cytotoxicity. Combination therapy of gefitinib and 1,25(OH)₂D₃ by targeting IRX4 and NANOG, could provide a promising strategy to improve gefitinib cytotoxicity.

Cancer Stem Cells: Acquisition, Characteristics, Therapeutic Implications, Targeting Strategies and Future Prospects

Since last two decades, the major cancer research has focused on understanding the characteristic properties and mechanism of formation of Cancer stem cells (CSCs), due to their ability to initiate tumor growth, self-renewal property and multi-drug resistance. The discovery of the mechanism of acquisition of stem-like properties by carcinoma cells via epithelial-mesenchymal transition (EMT) has paved a way towards a deeper understanding of CSCs and presented a possible avenue for the development of therapeutic strategies. In spite of years of research, various challenges, such as identification of CSC subpopulation, lack of appropriate experimental models, targeting cancer cells and CSCs specifically without harming normal cells, are being faced while dealing with CSCs. Here, we discuss the biology and characteristics of CSCs, mode of acquisition of stemness (via EMT) and development of multi-drug resistance, the role of tumor niche, the process of dissemination and metastasis, therapeutic implications of CSCs and necessity of targeting them. We emphasise various strategies being developed to specifically target CSCs, including those targeting biomarkers, key pathways and microenvironment. Finally, we focus on the challenges that need to be subdued and propose the aspects that need to be addressed in future studies in order to broaden the understanding of CSCs and develop novel strategies to eradicate them in clinical applications. Graphical Abstract Cancer Stem Cells(CSCs) have gained much attention in the last few decades due to their ability to initiate tumor growth and, self-renewal property and multi-drug resistance. Here, we represent the CSC model of cancer, Characteristics of CSCs, acquisition of stemness and metastatic dissemination of cancer, Therapeutic implications of CSCs and Various strategies being employed to target and eradicate CSCs.

Defining the "Metastasome": Perspectives from the genome and molecular landscape in colorectal cancer for metastasis evolution and clinical consequences

Metastasis still poses the highest challenge for personalized therapy in cancer, partly due to a still incomplete understanding of its molecular evolution. We recently presented the most comprehensive whole-genome study of colorectal metastasis vs. matched primary tumors and suggested novel components of disease progression and metastasis evolution, some of them potentially relevant for targeted therapy. In this review, we try to put these findings into perspective with latest discoveries of colleagues and recent literature, and propose a systematic international team effort to collectively define the "metastasome", a term we introduce to summarize all genomic, epigenomic, transcriptomic, further -omic, molecular and functional characteristics rendering metastases different from primary tumors. Based on recent discoveries, we propose a revised metastasis model for colorectal cancer which is based on a common ancestor clone, early dissemination but flexible early or late stage clonal separation paralleling stromal interactions. Furthermore, we discuss hypotheses on site-specific metastasis, colorectal cancer progression, metastasis-targeted diagnosis and therapy, and metastasis prevention based on latest metastasome data.

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.

Tumour stem cells in schwannoma: A review

Schwannoma is a peripheral nerve tumour, accounting for 5% of benign soft tissue tumours, with vestibular schwannoma comprising 6% of all intracranial tumours. The tumour stem cell concept is rapidly gaining traction underscoring the understanding of tumourigenesis. It proposes a small subpopulation of primitive cells as the origin of the tumour and these cells account for treatment resistance, local recurrence and distant metastasis in malignant tumours. This review outlines the stem cell markers used to identify and characterise stem cells and progenitor cells in tumours and examines current evidence of the presence of tumour stem cells in schwannoma.

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.

The IGF2/IGF1R/Nanog Signaling Pathway Regulates the Proliferation of Acute Myeloid Leukemia Stem Cells

Acute myeloid leukemia is an aggressive disease characterized by clonal proliferation and differentiation into immature hematopoietic cells of dysfunctional myeloid precursors. Accumulating evidence shows that CD34⁺CD38^- leukemia stem cells (LSCs) are responsible for drug resistance, metastasis, and relapse of leukemia. In this study, we found that Nanog, a transcription factor in stem cells, is significantly overexpressed in CD34⁺ populations from patients with acute myeloid leukemia and in LSCs from leukemia cell lines. Our data demonstrate that the knockdown of Nanog inhibited proliferation and induced cell cycle arrest and cell apoptosis. Moreover, Nanog silencing suppressed the leukemogenesis of LSCs in mice. In addition, we found that these functions of Nanog were regulated by the insulin-like growth factor receptor (IGF1R) signaling pathway. Nanog overexpression rescued the colony formation ability of LSCs treated with picropodophyllin (PPP), an IGF1R inhibitor. By contrast, knockdown of Nanog abolished the effects of IGF2 on the colony formation ability of these LSCs. These findings suggest that the IGF2/IGF1R/Nanog signaling pathway plays a critical role in LSC proliferation.

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

Cancer stem cells (CSCs) are a small subset of tumor cells that exhibit stem cell-like properties and contribute in treatment failure. To clarify the expression and prognostic significance of several CSC markers in non-small cell lung cancer, we retrospectively analyzed 368 patients with adenocarcinoma (n = 226) or squamous cell carcinoma (n = 142). We correlated the expression of six CSC markers – CD133, CD44, aldehyde dehydrogenase 1 (ALDH1), sex determining region Y-box 2 (SOX2), octamer binding transcription factor 4 (OCT4), and Nanog – with clinicopathologic and molecular variables and survival outcomes. In adenocarcinoma, CD133, ALDH1 and CD44 expression was associated with low pathologic stage and absence of lymphovascular invasion, while Nanog expression correlated with high histologic grade, lymphatic invasion and increased expression of Snail-1, a transcription factor associated with epithelial-mesenchymal transition. CSC marker expression was also associated with histologic subtypes in adenocarcinoma. Multivariate analysis showed that high Nanog expression was an independent factor associated with a poor prognosis in adenocarcinoma. CSC markers had no prognostic value in squamous cell carcinoma. These results suggest that Nanog is an independent negative prognostic factor that may be associated with epithelial-mesenchymal transition in lung adenocarcinoma.

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.

Immunohistochemical analysis of NANOG expression and epithelial-mesenchymal transition in pulmonary sarcomatoid carcinoma

Pulmonary sarcomatoid carcinomas (PSCs) are defined as a group of poorly differentiated non-small cell lung cancers that demonstrate sarcoma-like differentiation. The mechanism of mesenchymal differentiation in PSC is epithelial-mesenchymal transition (EMT). The expression of homeobox protein NANOG (NANOG), which regulates the pluripotency of embryonic stem cells, is associated with the EMT process. Therefore, the present study aimed to assess the expression level of NANOG and the status of the EMT process in PSC. The data of patients with PSC were retrospectively reviewed and immunohistochemical analyses were performed on patient samples to examine the expression of NANOG and EMT-associated proteins. The comparator group included randomly selected patients with matched clinicopathological characteristics who had pulmonary adenocarcinoma (PA). In the present study, 12 patients with PSC (4 females and 8 males) were enrolled; their median age was 65 years (range, 36-79 years), and the number of patients with stage IB, IIB, IIIA, IIIB and IV disease were 1, 1, 1, 1 and 8, respectively. The immunoreactive score (IRS) for E-cadherin was significantly lower in the PSC group compared with the PA group (P<0.0001), whereas the IRS for vimentin was significantly higher in the PSC group compared with the PA group (P<0.0001). However, the IRS for NANOG was significantly decreased in the PSC group compared with the PA group (P<0.0001), which suggests that NANOG does not serve an essential role in EMT in PSC. In addition, the overall survival of patients with PSC was significantly lower compared with that of patients with PA (median survival time, 7.0 vs. 35.6 months, respectively; P=0.0256). However, no significant difference was observed in the OS of patients who expressed low compared with high levels of NANOG (P=0.4416). In conclusion, it was clearly demonstrated that cytoplasmic NANOG expression was significantly lower in PSC compared with PA, and that the EMT process in PSC was accelerated, compared with that in PA.

Curcumin Suppresses Lung Cancer Stem Cells via Inhibiting Wnt/β-catenin and Sonic Hedgehog Pathways

Cancer stem cells (CSCs) are highly implicated in the progression of human cancers. Thus, targeting CSCs may be a promising strategy for cancer therapy. Wnt/β-catenin and Sonic Hedgehog pathways play an important regulatory role in maintaining CSC characteristics. Natural compounds, such as curcumin, possess chemopreventive properties. However, the interventional effect of curcumin on lung CSCs has not been clarified. In the present study, tumorsphere formation assay was used to enrich lung CSCs from A549 and H1299 cells. We showed that the levels of lung CSC markers (CD133, CD44, ALDHA1, Nanog and Oct4) and the number of CD133-positive cells were significantly elevated in the sphere-forming cells. We further illustrated that curcumin efficiently abolished lung CSC traits, as evidenced by reduced tumorsphere formation, reduced number of CD133-positive cells, decreased expression levels of lung CSC markers, as well as proliferation inhibition and apoptosis induction. Moreover, we demonstrated that curcumin suppressed the activation of both Wnt/β-catenin and Sonic Hedgehog pathways. Taken together, our data suggested that curcumin exhibited its interventional effect on lung CSCs via inhibition of Wnt/β-catenin and Sonic Hedgehog pathways. These novel findings could provide new insights into the potential therapeutic application of curcumin in lung CSC elimination and cancer intervention. Copyright © 2017 John Wiley & Sons, Ltd.

miR-150 Suppresses the Proliferation and Tumorigenicity of Leukemia Stem Cells by Targeting the Nanog Signaling Pathway

Proliferation, a key feature of cancer cells, accounts for the majority of cancer-related diseases resulting in mortality. MicroRNAs (miRNAs) plays important post-transcriptional modulation roles by acting on multiple signaling pathways, but the underlying mechanism in proliferation and tumorigenicity is unclear. Here, we identified the role of miR-150 in proliferation and tumorigenicity in leukemia stem cells (LSCs; CD34+CD38- cells). miR-150 expression was significantly down-regulated in LSCs from leukemia cell lines and clinical samples. Functional assays demonstrated that increased miR-150 expression inhibited proliferation and clonal and clonogenic growth, enhanced chemosensitivity, and attenuated tumorigenic activity of LSCs in vitro. Transplantation animal studies revealed that miR-150 overexpression progressively abrogates tumor growth. Immunohistochemistry assays demonstrated that miR-150 overexpression enhanced caspase-3 level and reduced Ki-67 level. Moreover, luciferase reporter assays indicated Nanog is a direct and functional target of miR-150. Nanog silencing using small interfering RNA recapitulated anti-proliferation and tumorigenicity inhibition effects. Furthermore, miR-150 directly down-regulated the expression of other cancer stem cell factors including Notch2 and CTNNB1. These results provide insights into the specific biological behavior of miR-150 in regulating LSC proliferation and tumorigenicity. Targeting this miR-150/Nanog axis would be a helpful therapeutic strategy to treat acute myeloid leukemia.

CRISPR/Cas9-mediated gene knockout of NANOG and NANOGP8 decreases the malignant potential of prostate cancer cells

NANOG expression in prostate cancer is highly correlated with cancer stem cell characteristics and resistance to androgen deprivation. However, it is not clear whether NANOG or its pseudogenes contribute to the malignant potential of cancer. We established NANOG- and NANOGP8-knockout DU145 prostate cancer cell lines using the CRISPR/Cas9 system. Knockouts of NANOG and NANOGP8 significantly attenuated malignant potential, including sphere formation, anchorage-independent growth, migration capability, and drug resistance, compared to parental DU145 cells. NANOG and NANOGP8 knockout did not inhibit in vitro cell proliferation, but in vivo tumorigenic potential decreased significantly. These phenotypes were recovered in NANOG- and NANOGP8-rescued cell lines. These results indicate that NANOG and NANOGP8 proteins are expressed in prostate cancer cell lines, and NANOG and NANOGP8 equally contribute to the high malignant potential of prostate cancer.

Clinical implications of the coexpression of SRC1 and NANOG in HER-2-overexpressing breast cancers

Objective

Given the lack of clarity on the expression status of SRC1 protein in breast cancer, we attempted to ascertain the clinical implications of the expression of this protein in breast cancer.

Methods

Samples from 312 breast cancer patients who were followed up for 5 years were analyzed in this study. The associations of SRC1 expression and clinicopathological factors with the prognosis of breast cancer were determined.

Results

The 312 breast cancer patients underwent radical resection, and 155 (49.68%) of them demonstrated high expression of SRC1 protein. No significant differences were found for tumor size, estrogen receptor expression, or progesterone receptor expression (P=0.191, 0.888, or 0.163, respectively). It is noteworthy that SRC1 expression was found to be related to HER-2 and Ki-67 expression (P=0.044 and P=0.001, respectively). According to logistic regression analysis, SRC1 expression was also significantly correlated with Ki-67 and HER-2 expression (P=0.032 and P=0.001, respectively). Survival analysis showed that patients with a high expression of SRC1 and NANOG and those with SRC1 and NANOG coexpression had significantly poorer postoperative disease-specific survival than those with no expression in the HER-2-positive group (P=0.032, 0.01, and P=0.01, respectively).

Conclusion

High SRC1 protein expression was related to the prognosis of HER-2-overexpressing breast cancers.

Oncogenic NanogP8 expression regulates cell proliferation and migration through the Akt/mTOR signaling pathway in human gastric cancer - SGC-7901cell line

BACKGROUND

Although elevated expression of NanogP8 has been detected in many human tumor tissues, its role in gastric tumorigenesis remains unclear. Therefore, this study aimed to investigate the function and regulatory mechanism of NanogP8 in gastric cancer.

METHODS

In this study, NanogP8 cDNA was amplified by real time polymerase chain reaction from the human gastric cancer cell line SGC-7901. The shRNA for RNA interference was established. The NanogP8, pAkt, Akt, pERK, ERK, p-mTOR, and mTOR proteins were detected by using the Western blot assay. Cell viability was evaluated by using the CCK-8 assay. Cell migration and invasion were also examined by using the transwell assay.

RESULTS

The results indicated that the NanogP8 overexpression promoted proliferation and migration of SGC-7901 cell line, whereas its ablation exerted opposite effects. Interestingly, NanogP8 activated Akt, a key mediator of survival signals, and without affecting total Akt protein level. The NanogP8-increased gastric cell proliferation was downregulated by Akt inhibition. Our results further showed that increasing NanogP8 expression in human gastric cancer cells promoted cell proliferation by activating the AKT/mTOR pathway and further maintained gastric cell survival.

CONCLUSION

Our findings extend the knowledge regarding the oncogenic functions and proved that the NanogP8 regulates cell proliferation and migration by Akt/mTOR signaling pathway in human gastric cancer SGC-7901cell line.

Cancer Stem Cells: The Potential Targets of Chinese Medicines and Their Active Compounds

The pivotal role of cancer stem cells (CSCs) in the initiation and progression of malignancies has been rigorously validated, and the specific methods for identifying and isolating the CSCs from the parental cancer population have also been rapidly developed in recent years. This review aims to provide an overview of recent research progress of Chinese medicines (CMs) and their active compounds in inhibiting tumor progression by targeting CSCs. A great deal of CMs and their active compounds, such as Antrodia camphorate, berberine, resveratrol, and curcumin have been shown to regress CSCs, in terms of reversing drug resistance, inducing cell death and inhibiting cell proliferation as well as metastasis. Furthermore, one of the active compounds in coptis, berbamine may inhibit tumor progression by modulating microRNAs to regulate CSCs. The underlying molecular mechanisms and related signaling pathways involved in these processes were also discussed and concluded in this paper. Overall, the use of CMs and their active compounds may be a promising therapeutic strategy to eradicate cancer by targeting CSCs. However, further studies are needed to clarify the potential of clinical application of CMs and their active compounds as complementary and alternative therapy in this field.

The prognostic value of whole blood SOX2, NANOG and OCT4 mRNA expression in advanced small-cell lung cancer

BACKGROUND

The data on expression and clinical impact of cancer stem cell markers SOX2, NANOG and OCT4 in lung cancer is still lacking. The aim of our study was to compare SOX2, NANOG and OCT4 mRNA expression levels in whole blood between advanced small-cell lung cancer (SCLC) patients and healthy controls, and to correlate mRNA expression with progression-free survival (PFS) after first-line chemotherapy and overall survival (OS) in advanced SCLC patients.

PATIENTS AND METHODS

50 advanced SCLC patients treated with standard chemotherapy and followed at University Clinic Golnik, Slovenia, between 2009 and 2013 were prospectively included. SOX2, NANOG and OCT4 mRNA expression levels were determined using TaqMan qPCR in whole blood collected prior to chemotherapy. Whole blood of 34 matched healthy individuals with no cancerous disease was also tested.

RESULTS

SOX2 mRNA expression was significantly higher in whole blood of SCLC patients compared to healthy controls (p = 0.006). Significant correlation between SOX2 mRNA expression levels and the number of distant metastatic sites was established (p = 0.027). In survival analysis, patients with high SOX2 expression had shorter OS (p = 0.017) and PFS (p = 0.046). In multivariate Cox analysis, an independent value of high SOX2 expression for shorter OS (p = 0.002), but not PFS was confirmed. No significant differences were observed for NANOG or OCT4 expression levels when comparing SCLC patients and healthy controls neither when analysing survival outcomes in SCLC patients.

CONCLUSIONS

SOX2 mRNA expression in whole blood might be a promising non-invasive marker for molecular screening of SCLC and important prognostic marker in advanced chemotherapy-treated SCLC patients, altogether indicating important role of cancer stem-like cell (CSC) regulators in cancer spread. Further evaluation of SOX2 as a possible screening/prognostic marker and a therapeutic target of SCLC is warranted.

Expressions of stem cell transcription factors Nanog and Oct4 in renal cell carcinoma tissues and clinical significance

We aimed to detect the expressions of stem cell transcription factors Nanog and Oct4 in renal cell carcinoma (RCC) tissues. Nanog and Oct4 mRNA expressions in RCC tissues significantly exceeded those in paracancerous tissues (p < 0.01 and p < 0.05), being positively correlated with histological grade (p < 0.01 and p < 0.05) and TNM stage (p < 0.05). With increasing TNM stage (p < 0.01) and lymphatic metastasis (p < 0.05), the positive expression rate of Nanog protein increased. RCC patients with low Nanog and Oct4 expressions in tumor tissues had significantly higher survival rates (p < 0.05). High Nanog and Oct4 expressions may be potential therapeutic targets.

Pluripotency transcription factors in lung cancer-a review

Lung cancer is the leading cause of cancer-related mortality worldwide. Diagnosis of lung cancer in an early stage is still a challenge due to the asymptomatic course of early stages of the disease and the lack of a standard screening program for the population. Nowadays, learning about the mechanisms that lead to cancerogenesis in the lung is crucial for the development of new diagnostic and therapeutic strategies. Recently, many studies have proved that cancer stem cells (CSCs) are responsible for the initiation, progression, metastasis, recurrence, and even resistance of chemo- and radiotherapeutic treatment in patients with lung cancer. The expression of pluripotency transcription factors is responsible for stemness properties. In this review, we summarize the current knowledge on the role of CSCs and pluripotency transcription factors in lung carcinogenesis.

Concise Review: NANOG in Cancer Stem Cells and Tumor Development: An Update and Outstanding Questions

The homeobox domain transcription factor NANOG, a key regulator of embryonic development and cellular reprogramming, has been reported to be broadly expressed in human cancers. Functional studies have provided strong evidence that NANOG possesses protumorigenic attributes. In addition to promoting self-renewal and long-term proliferative potential of stem-like cancer cells, NANOG-mediated oncogenic reprogramming may underlie clinical manifestations of malignant disease. In this review, we examine the molecular origin, expression, biological activities, and mechanisms of action of NANOG in various malignancies. We also consider clinical implications such as correlations between NANOG expression and cancer prognosis and/or response to therapy. We surmise that NANOG potentiates the molecular circuitry of tumorigenesis, and thus may represent a novel therapeutic target or biomarker for the diagnosis, prognosis, and treatment outcome of cancer. Finally, we present critical pending questions relating NANOG to cancer stem cells and tumor development.