Correlation of cancer stem cell markers and immune cell markers in resected non-small cell lung cancer

Density of tumor-infiltrating NK and Treg cells is associated with 5 years progression-free and overall survival in resected lung adenocarcinoma

Surgical resection of pulmonary adenocarcinoma is considered to be curative but progression-free survival (PFS) has remained highly variable. Antitumor immune response may be important, however, the prognostic significance of tumor-infiltrating natural killer (NK) and regulatory T (Treg) lymphocytes is uncertain. Resected pulmonary adenocarcinoma tissues (n = 115) were studied by immunohistochemical detection of NKp46 and FoxP3 positivity to identify NK and Treg cells, respectively. Association of cell densities with clinicopathological features and progression-free survival (PFS) as well as overall survival (OS) were analyzed with a follow-up time of 60 months. Both types of immune cells were accumulated predominantly in tumor stroma. NK cell density showed association with female gender, non-smoking and KRAS wild-type status. According to Kaplan-Meier analysis, PFS and OS proved to be longer in patients with high NK or Treg cell densities (p = 0.0293 and p = 0.0375 for PFS, p = 0.0310 and p = 0.0448 for OS, respectively). Evaluating the prognostic effect of the combination of NK and Treg cell density values revealed that PFS and OS were significantly longer in NKhigh/Treghigh cases compared to the other groups combined (p = 0.0223 and p = 0.0325, respectively). Multivariate Cox regression analysis indicated that high NK cell density was independent predictor of longer PFS while high NK and high Treg cell densities both proved significant predictors of longer OS. The NKhigh/Treghigh combination also proved to be an independent prognostic factor for both PFS and OS. In conclusion, NK and Treg cells can be components of the innate and adaptive immune response at action against progression of pulmonary adenocarcinoma.

Identification of EZH2 as Cancer Stem Cell Marker in Clear Cell Renal Cell Carcinoma and the Anti-Tumor Effect of Epigallocatechin-3-Gallate (EGCG)

The aim of the study was to develop a new therapeutic strategy to target cancer stem cells (CSCs) in clear cell renal cell carcinoma (ccRCC) and to identify typical CSC markers to improve therapy effectiveness. It was found that the corrected-mRNA expression-based stemness index was upregulated in kidney renal clear cell carcinoma (KIRC) tissues compared to non-tumor tissue and increased with higher tumor stage and grade. EZH2 was identified as a CSC marker and prognosis factor for KIRC patients. The expression of EZH2 was associated with several activated tumor-infiltrating immune cells. High expression of EZH2 was enriched in immune-related pathways, low expression was related to several metabolic pathways. Epigallocatechin-3-gallate (EGCG) was identified as the most potent suppressor of EZH2, was able to inhibit viability, migration, and invasion, and to increase the apoptosis rate of ccRCC CSCs. KIF11, VEGF, and MMP2 were identified as predictive EGCG target genes, suggesting a potential mechanism of how EZH2 might regulate invasiveness and migration. The percentages of FoxP3+ Treg cells in the peripheral blood mononuclear cells of ccRCC patients decreased significantly when cultured with spheres pretreated with EGCG plus sunitinib compared to spheres without treatment. Our findings provide new insights into the treatment options of ccRCC based on targeting CSCs.

Lung Cancer Stem Cells and Their Clinical Implications

It is now widely accepted that stem cells exist in various cancers, including lung cancer, which are referred to as cancer stem cells (CSCs). CSCs are defined in this context as the subset of tumor cells with the ability to form tumors in serial transplantation and cloning assays and form tumors at metastatic sites. Mouse models of lung cancer have shown that lung CSCs reside in niches that are essential for the maintenance of stemness, plasticity, enable antitumor immune evasion, and provide metastatic potential. Similar to normal lung stem cells, Notch, Wnt, and the Hedgehog signaling cascades have been recruited by the CSCs to regulate stemness and also provide therapy-driven resistance in lung cancer. Compounds targeting β-catenin and Sonic hedgehog (Shh) activity have shown promising anti-CSC activity in preclinical murine models of lung cancer. Understanding CSCs and their niches in lung cancer can answer fundamental questions pertaining to tumor maintenance and associated immune regulation and escape that appear important in the quest to develop novel lung cancer therapies and enhance sensitivity to currently approved chemo-, targeted-, and immune therapeutics.

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 value of immune cells in the tumor microenvironment of early-stage lung cancer: a meta-analysis

BACKGROUND

Early-stage non-small cell lung cancer (NSCLC) patients carry significant risk of recurrence post-surgery. In-depth characterization of the immune tumor microenvironment (TME) can have prognostic value. This study aimed to evaluate the association of individual immune cell types in the TME with clinical outcomes in surgically resected, early-stage NSCLC.

METHODS

We performed a systematic literature search of the National Library of Medicine database through November 2019, investigating predefined biomarkers (CD3+ T cells, CD4+ T helper cells, CD8+ cytotoxic T cells, CD20+ B cells, CD56+ & CD57+ Natural Killer (NK) cells, CD68+ Tissue Associated Macrophages (TAMS), FoxP3+ T regulatory cells, and Mast Cells (MC)), and their association with survival following PRISMA guidelines.

RESULTS

Studies that adjusted for important clinical covariates (such as stage and age) showed that higher levels of CD8+ cytotoxic T cells were associated with improved OS (HR = 0.68; 95% CI, 0.50-0.93) and DFS (HR = 0.60; 95% CI, 0.41-0.87), while increased CD20+ B cells (HR = 0.16; 95% CI, 0.04-0.64) and CD 56/57+ NK cells (HR = 0.50; 95% CI, 0.26-0.95) were associated with improved OS; lung cancers with increased FoxP3+ T regulatory cells (HR = 2.22; 95% CI, 1.47-3.34) had worse OS.

CONCLUSIONS

Immune cell components of the TME have prognostic value in early-stage, surgically resected NSCLC, and may reveal which patients are more likely to need additional systemic treatment, including immunotherapy. Clinical covariates need to be considered when evaluating the prognostic value of immune cells in the TME.

Correlating tumor-infiltrating lymphocytes and lung cancer stem cells: a cross-sectional study

Background

Lung cancer stem cells (LCSCs) are endowed with high aldehyde dehydrogenase (ALDH) expression and play roles in tumor proliferation, metastasis, and drug resistance. Their elusive nature may allow them to escape the immune response by tumor-infiltrating lymphocytes (TILs), which can positively affect the outcome in non-small cell lung cancer (NSCLC) patients. Despite independent investigations on both LCSCs and TILs, the relationship between the two has been very marginally considered. We analyzed whether these two cell types may be related as a prerequisite for novel diagnostic and therapeutic approaches.

Methods

In this cross-sectional study, NSCLC human surgical specimens from 12 patients were tested by ALDEFLUOR assay to identify ALDH^high cells. Fluorescence-activated cell sorting (FACS) analyses for CD3+, CD4+, and CD8+ TILs were performed in combination with immunohistochemistry evaluation.

Results

Statistically positive correlations were found between ALDH+ and CD8+, and between ALDH+ and CD3+ cells populations; no correlation was found between ALDH+ and CD4+ cells. The expression of CD3+ and CD8+ by cells accounted for 40.1% and 58.7%, respectively, of the variability of ALDH+ cell expression by an R-squared index, which highlights the strong correlation between TILs and LCSCs. Immunohistochemistry revealed 6-25% positive cells.

Conclusions

We report a correlation between cytotoxic TILs and LCSCs, which may contribute to the future development of targeted therapies focusing on the different roles of lymphocytes against lung cancer.

Expression profiles of long non-coding RNA in mouse lung tissue exposed to radon

Long non-coding RNAs (lncRNA) exert biological functions by interacting with RNAs, proteins, and DNA. Although lung damage associated with radon exposure was attributed to disturbances in microRNA and protein expression, the influence of radon on lncRNA is at present not known. The aim of this study was to (1) examine the effect of radon on lncRNA-mediated expression of transcription factors in mRNA in mouse lung tissue and (2) determine potential function and targets. Female BALB/c mice were divided into two groups: control and radon exposure to approximately 100,000 Bq/m³ (equivalent up to 60 working level month, WLM).RNA was extracted from lung tissue and used for high through-put lncRNA microarray analysis. A total of 1256 lncRNA transcripts were differentially expressed between the two groups of mice. Among these, the top 200 lncRNA-mRNA sets, with fold change of >2 and p-value <.05, were selected for KEGG analysis. Functional analysis via bioinformatics prediction in this study also suggested involvement of ErbB and Notch pathways in radon-induced mouse pulmonary injury. The results from immunohistochemical and Western blot analysis indicated that EbB2 and k-Ras protein expressions were significantly increased. In conclusion, approximately 1,000 dysregulated lncRNA transcripts were found in radon-exposed mice and these lncRNA may play an important role in lung damage following radon exposure. The observations in this study also suggested that ErbB2 and Notch pathways are activated and may be involved in radon-induced pulmonary toxicity.

Wnt Signaling in Cancer Metabolism and Immunity

The Wingless (Wnt)/β-catenin pathway has long been associated with tumorigenesis, tumor plasticity, and tumor-initiating cells called cancer stem cells (CSCs). Wnt signaling has recently been implicated in the metabolic reprogramming of cancer cells. Aberrant Wnt signaling is considered to be a driver of metabolic alterations of glycolysis, glutaminolysis, and lipogenesis, processes essential to the survival of bulk and CSC populations. Over the past decade, the Wnt pathway has also been shown to regulate the tumor microenvironment (TME) and anti-cancer immunity. Wnt ligands released by tumor cells in the TME facilitate the immune evasion of cancer cells and hamper immunotherapy. In this review, we illustrate the role of the canonical Wnt/β-catenin pathway in cancer metabolism and immunity to explore the potential therapeutic approach of targeting Wnt signaling from a metabolic and immunological perspective.

[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。