Cancer stem-neuroendocrine cells in an atypical carcinoid case report

Dissecting Tumor Growth: The Role of Cancer Stem Cells in Drug Resistance and Recurrence

Simple Summary

Cancer is one of the most debated problems all over the world. Cancer stem cells are considered responsible of tumor initiation, metastasis, drug resistance, and recurrence. This subpopulation of cells has been found into the tumor bulk and showed the capacity to self-renew, differentiate, up to generate a new tumor. In the last decades, several studies have been set on the molecular mechanisms behind their specific characteristics as the Wnt/β-catenin signaling, Notch signaling, Hedgehog signaling, transcription factors, etc. The most powerful part of CSCs is represented by the niches as “promoter” of their self-renewal and “protector” from the common oncological treatment as chemotherapy and radiotherapy. In our review article we highlighted the primary mechanisms involved in CSC tumorigenesis for the setting of further targets to control the metastatic process.

Abstract

Emerging evidence suggests that a small subpopulation of cancer stem cells (CSCs) is responsible for initiation, progression, and metastasis cascade in tumors. CSCs share characteristics with normal stem cells, i.e., self-renewal and differentiation potential, suggesting that they can drive cancer progression. Consequently, targeting CSCs to prevent tumor growth or regrowth might offer a chance to lead the fight against cancer. CSCs create their niche, a specific area within tissue with a unique microenvironment that sustains their vital functions. Interactions between CSCs and their niches play a critical role in regulating CSCs’ self-renewal and tumorigenesis. Differences observed in the frequency of CSCs, due to the phenotypic plasticity of many cancer cells, remain a challenge in cancer therapeutics, since CSCs can modulate their transcriptional activities into a more stem-like state to protect themselves from destruction. This plasticity represents an essential step for future therapeutic approaches. Regarding self-renewal, CSCs are modulated by the same molecular pathways found in normal stem cells, such as Wnt/β-catenin signaling, Notch signaling, and Hedgehog signaling. Another key characteristic of CSCs is their resistance to standard chemotherapy and radiotherapy treatments, due to their capacity to rest in a quiescent state. This review will analyze the primary mechanisms involved in CSC tumorigenesis, with particular attention to the roles of CSCs in tumor progression in benign and malignant diseases; and will examine future perspectives on the identification of new markers to better control tumorigenesis, as well as dissecting the metastasis process.

Cancer stem cells and macrophages: molecular connections and future perspectives against cancer

Cancer stem cells (CSCs) have been considered the key drivers of cancer initiation and progression due to their unlimited self-renewal capacity and their ability to induce tumor formation. Macrophages, particularly tumor-associated macrophages (TAMs), establish a tumor microenvironment to protect and induce CSCs development and dissemination. Many studies in the past decade have been performed to understand the molecular mediators of CSCs and TAMs, and several studies have elucidated the complex crosstalk that occurs between these two cell types. The aim of this review is to define the complex crosstalk between these two cell types and to highlight potential future anti-cancer strategies.

ALDH Expression in Angiosarcoma of the Lung: A Potential Marker of Aggressiveness?

Background: Primary angiosarcoma of the lung is a very aggressive rare malignant disease resulting in a severe prognosis (1). This type of cancer represents about 2% of all soft tissue sarcomas and has a high rate of metastasis through the hematogenous route. For the rarity of this malignant vascular tumor it is still challenging to set a diagnosis (1). The diagnostic features that have thus far been considered include primarily clinical and radiological findings. In some cases, immunohistochemical characteristics based on the most common markers used in pathology have been described. The aim of this report is to present two cases of angiosarcoma of the lung in which the aldehyde dehydrogenase (ALDH) marker was analyzed by immunohistochemistry.

Methods: We report two cases of angiosarcoma of the lung in patients underwent lung surgery at our Unit. In addition to the standard histopathological analysis for this disease, immunohistochemistry using an ALDH1A1 antibody was performed in both of the cases. For ALDH quantification, a semi-quantitative method based on the positivity of the tumor cells was used: 0 (<5%), 1 (5–25%), 2 (>25–50%), 3 (>50–75%), 4 (>75%).

Results: One patient with recurrent lung disease survived, achieving complete remission after chemo- and radiotherapy. The second patient died of recurrent disease within 5 years of diagnosis. ALDH1A1 was evaluated in both of these cases using an immunohistochemistry scoring system based on the positivity for this marker. The scores were consistent with the patients' clinical outcomes, as the lower (score 1) was observed in the patient with the better clinical outcome, while the higher (score 3) was seen in the patient with the worse outcome.

Conclusion: Our data suggest that ALDH may be an important clinical marker in angiosarcoma of the lung. Although further studies need to be performed in a larger cohort of patients, we believe that, if the results will be confirmed, ALDH1A1 may be used to stratify patients in terms of prognosis and for targeted therapy.

Defining lung cancer stem cells exosomal payload of miRNAs in clinical perspective

Since the first publication regarding the existence of stem cells in cancer [cancer stem cells (CSCs)] in 1994, many studies have been published providing in-depth information about their biology and function. This research has paved the way in terms of appreciating the role of CSCs in tumour aggressiveness, progression, recurrence and resistance to cancer therapy. Targeting CSCs for cancer therapy has still not progressed to a sufficient degree, particularly in terms of exploring the mechanism of dynamic interconversion between CSCs and non-CSCs. Besides the CSC scenario, the problem of cancer dissemination has been analyzed in-depth with the identification and isolation of microRNAs (miRs), which are now considered to be compelling molecular markers in the diagnosis and prognosis of tumours in general and specifically in patients with non-small cell lung cancer. Paracrine release of miRs via “exosomes” (small membrane vesicles (30-100 nm), the derivation of which lies in the luminal membranes of multi-vesicular bodies) released by fusion with the cell membrane is gaining popularity. Whether exosomes play a significant role in maintaining a dynamic equilibrium state between CSCs and non-CSCs and their mechanism of activity is as yet unknown. Future studies on CSC-related exosomes will provide new perspectives for precision-targeted treatment strategies.

Cancer Stem-Like Cells in a Case of an Inflammatory Myofibroblastic Tumor of the Lung

Background: Inflammatory myofibroblast tumor (IMT) is a rare tumor with obscure etiopathogenesis in which different inflammatory cells and myofibroblastic spindle cells are seen histologically. Although the majority of these neoplasms have a benign clinical course, the malignant form has also been reported. The gold standard is surgical treatment for complete removal. Our report describes a 50-year-old woman who underwent surgery for IMT of the lung. The aim is to determine whether cancer stem cells may be present in IMT of the lung.

Methods: In April 2018, the patient underwent surgery for tumor mass asportation through lateral thoracotomy. The histology of the tumor was consistent with IMT of the lung. The ALDEFLUOR assay, after tissue digestion, was used to identify and sort human lung cancer cells expressing high and low aldehyde dehydrogenase (ALDH) activity. SOX2, NANOG, OCT-4, and c-MYC positivity were additionally determined by immunohistochemistry.

Results: The specimen contained 1.10% ALDH^high cells among all viable lung cancer cells, which indicates the population of cancer stem cells is not negligible. Immunohistochemically assessed cell positivity for ALDH1A1, SOX2, NANOG, OCT-4, and c-MYC, which are considered as lung cancer stem-like cells markers.

Conclusion: For the first time, we demonstrated the presence of cancer stem cells in a case of IMT of the lung. This finding may provide a base for considering new pathological and molecular aspects of this tumor. This perspective suggests further studies to understand the possibility of developing recurrence depending on the presence of cancer stem cells.

CD44+/EPCAM+ cells detect a subpopulation of ALDHhigh cells in human non-small cell lung cancer: A chance for targeting cancer stem cells?

OBJECTIVES

Several studies demonstrated that aldehyde dehydrogenase (ALDH) and CD44 are the most considered cancer stem cells (CSC) markers. However, a comparison between ALDH high cells and CD44+ cells have been previously described with no significant correlation. Indeed, the aim of the present research is to identify a superficial marker able to match with ALDH high cells population in freshly isolated human lung cancer cells.

MATERIALS AND METHODS

This cross-sectional study analyzed the expression of ALDH^high/low cells and the positivity for CD44 and epithelium cell adhesion molecule (EPCAM) antigens in surgical lung cancer tissues. The main approach was a cytofluorimetric analysis of ALDH expression and positivity for CD44/EPCAM on primary cell population obtained from 23 patients harboring NSCLC.

RESULTS

There was a highly positive correlation between the expressions of ALDH^high and CD44+/EPCAM+ cells, with a Pearson's correlation coefficient equal to 0.69 (95% CI 0.39-0.86; P = 0.0002), and Spearman's correlation coefficient equal to 0.52 (P = 0.0124). The average paired difference between the expression of ALDH^high and CD44+/EPCAM+ cells was very close to 0, being 0.1% (SD 2.5%); there was no difference between these subpopulations in terms of means (95% CI = -1.0; 1.2%, P = 0.8464). These results highlight a strong similarity between ALDH^high and CD44+/EPCAM+ cells.

CONCLUSIONS

Our study is the first attempt which identifies a high correlation between the ALDH^high and the CD44+/EPCAM+ cells, thus suggesting the possibility to use this superficial marker for future target treatments against lung cancer stem cells.