Cancer stem cell-like characteristics and telomerase activity of the nasopharyngeal carcinoma radioresistant cell line CNE-2R

Comparative Analysis of Primary Ovarian Cancer Cells and Established Cell Lines as a New Tool for Studies on Ovarian Cancer Cell Complexity

Primary cancer cells reflect the genetic background and phenotype of a tumor. Immortalized cells with higher proliferation activity have an advantage over primary cells. The aim of the study was to immortalize the primary ovarian cancer (OvCa) cells using the plasmid-carrying human telomerase reverse transcriptase (hTERT) gene and compare their phenotype and biological activity with the primary cells. The primary OvCa3 A and OvCa7 A cells were isolated from the ascitic fluid of two high-grade serous ovarian cancer patients and were characterized using immunocytochemical methods, flow cytometry, real-time RT-PCR, Western blot, metabolic activity, and migratory potential. Both immortalized ovarian cancer cell lines mirrored the phenotype of primary cancer cells, albeit with modifications. The OvCa3 A hTERT cells kept the mesenchymal stem cell phenotype of CD73/CD90/CD105-positivity and were CD133-negative, whereas the cell population of OvCa7 A hTERT lost CD73 expression, but almost 90% of cells expressed the CD133 characteristic for the CSCs phenotype. Immortalized OvCa cells differed in gene expression level with respect to Sox2 and Oct4, which was associated with stemness properties. The OvCa7 A hTERT cells showed higher metabolic and migratory activity and ALDH1 expression than the corresponding primary OvCa cells. Both primary and immortalized cell lines were able to form spheroids. The newly established unique immortalized cell line OvCa7 A hTERT, with the characteristic of a serous ovarian cancer malignancy feature, and with the accumulation of the p53, Pax8, and overexpression of the CD133 and CD44 molecules, may be a useful tool for research on therapeutic approaches, especially those targeting CSCs in ovarian cancer and in preclinical 2D and 3D models.

Liver cancer stem cell dissemination and metastasis: uncovering the role of NRCAM in hepatocellular carcinoma

BACKGROUND

Liver cancer stem cells (LCSCs) play an important role in hepatocellular carcinoma (HCC), but the mechanisms that link LCSCs to HCC metastasis remain largely unknown. This study aims to reveal the contributions of NRCAM to LCSC function and HCC metastasis, and further explore its mechanism in detail.

METHODS

117 HCC and 29 non-HCC patients with focal liver lesions were collected and analyzed to assess the association between NRCAM and HCC metastasis. Single-cell RNA sequencing (scRNA-seq) was used to explore the biological characteristics of cells with high NRCAM expression in metastatic HCC. The role and mechanism of NRCAM in LCSC dissemination and metastasis was explored in vitro and in vivo using MYC-driven LCSC organoids from murine liver cells.

RESULTS

Serum NRCAM is associated with HCC metastasis and poor prognosis. A scRNA-seq analysis identified that NRCAM was highly expressed in LCSCs with MYC activation in metastatic HCC. Moreover, NRCAM facilitated LCSC migration and invasion, which was confirmed in MYC-driven LCSC organoids. The in vivo tumor allografts demonstrated that NRCAM mediated intra-hepatic/lung HCC metastasis by enhancing the ability of LCSCs to escape from tumors into the bloodstream. Nrcam expression inhibition in LCSCs blocked HCC metastasis. Mechanistically, NRCAM activated epithelial-mesenchymal transition (EMT) and metastasis-related matrix metalloproteinases (MMPs) through the MACF1 mediated β-catenin signaling pathway in LCSCs.

CONCLUSIONS

LCSCs typified by high NRCAM expression have a strong ability to invade and migrate, which is an important factor leading to HCC metastasis.

Olovnikov, Telomeres, and Telomerase. Is It Possible to Prolong a Healthy Life?

The science of telomeres and telomerase has made tremendous progress in recent decades. In this review, we consider it first in a historical context (the Carrel-Hayflick-Olovnikov-Blackburn chain of discoveries) and then review current knowledge on the telomere structure and dynamics in norm and pathology. Central to the review are consequences of the telomere shortening, including telomere position effects, DNA damage signaling, and increased genetic instability. Cell senescence and role of telomere length in its development are discussed separately. Therapeutic aspects and risks of telomere lengthening methods including use of telomerase and other approaches are also discussed.

The lipid rafts in cancer stem cell: a target to eradicate cancer

Cancer stem cells (CSCs) are a subpopulation of cancer cells with stem cell properties that sustain cancers, which may be responsible for cancer metastasis or recurrence. Lipid rafts are cholesterol- and sphingolipid-enriched microdomains in the plasma membrane that mediate various intracellular signaling. The occurrence and progression of cancer are closely related to lipid rafts. Emerging evidence indicates that lipid raft levels are significantly enriched in CSCs compared to cancer cells and that most CSC markers such as CD24, CD44, and CD133 are located in lipid rafts. Furthermore, lipid rafts play an essential role in CSCs, specifically in CSC self-renewal, epithelial-mesenchymal transition, drug resistance, and CSC niche. Therefore, lipid rafts are critical regulatory platforms for CSCs and promising therapeutic targets for cancer therapy.

The Role of Genetic Pathways in the Development of Chemoradiation Resistance in Nasopharyngeal Carcinoma (NPC) Patients

Management of nasopharyngeal carcinoma (NPC) remains elusive despite new developments and advancement that has been made in the current management approaches. A patient’s survival and prognosis remain dismal especially for a late-stage disease. This is highly attribute to the chemoradiation resistance. Arrays of genes and molecular mechanisms underlie the development of chemoradiation resistance in NPC. Imperatively, unravelling the true pathogenesis of chemoradiation resistance is crucial as these significant proteins and genes can be modulated to produce an effective therapeutic target. It is pivotal to identify the chemoradiation resistance at the very beginning in order to combat the chemoradiation resistance efficiently. Intense research in the genetic ecosphere is critical, as the discovery and development of novel therapeutic targets can be used for screening, diagnosis, and treating the chemoradiation resistance aggressively. This will escalate the management trajectory of NPC patients. This article highlights the significance of genetic and molecular factors that play critical roles in the chemoradiation resistance and how these factors may be modified for next-generation targeted therapy products.

Feprazone Mitigates IL-1β-Induced Cellular Senescence in Chondrocytes

The proinflammatory cytokine interleukin-1 β (IL-1β)-mediated cellular senescence in chondrocytes is involved in the development and pathological progression of osteoarthritis (OA). Feprazone, a nonsteroidal anti-inflammatory drug (NSAID) and a cyclooxygenase (COX) inhibitor, is widely used in clinics. This study aims to investigate whether Feprazone has a protective effect against IL-1β-induced cellular senescence in human chondrocytes. In this study, C-28/I2 chondrocytes were stimulated with IL-1β (10 ng/mL) in the presence or absence of Feprazone (10 and 20 μM). Cellular senescence was assessed using senescence-associated β-galactosidase (SA-β-Gal) staining. The cell cycle was examined using flow cytometry. Gene and protein expressions were determined with real-time polymerase chain reaction (PCR) and western blot analysis. We found that treatment with Feprazone ameliorated IL-1β-induced increase in cellular senescence. Feprazone increased telomerase activity and prevented cell cycle arrest in the G0/G1 phase. We also found that Feprazone reduced the expressions of plasminogen activator inhibitor-1 (PAI-1) and p21, two important regulators of cellular senescence. Additionally, treatment with Feprazone reduced the expressions of matrix metalloprotein (MMP-13) and a disintegrin-like and metalloproteinase with thrombospondin type-1 motif-5 (ADAMTS-5). Interestingly, Feprazone prevented the activation of nuclear factor kappa-B (NF-κB) by preventing nuclear translocation of NF-κB p65 and the luciferase activity of the NF-κB promoter. The results also show that Feprazone increased nuclear levels of nuclear factor erythroid 2-related factor-2 (Nrf2) and reduced the production of reactive oxygen species (ROS). Importantly, silencing of Nrf2 abolished the protective effects of Feprazone against IL-1β-induced NF-κB activation and cellular senescence. These findings shed light on the potential use of Feprazone in the treatment of OA based on a novel mechanism.

Role of Telomeres Shortening in Atherogenesis: An Overview

It is known that the shortening of the telomeres leads to cell senescence, accompanied by acquiring of pro-inflammatory phenotype. The expression of telomerase can elongate telomeres and resist the onset of senescence. The initiation of atherosclerosis is believed to be associated with local senescence of the endothelial cells of the arteries in places with either low or multidirectional oscillatory wall shear stress. The process of regeneration of the artery surface that has begun does not lead to success for several reasons. Atherosclerotic plaques are formed, which, when developed, lead to fatal consequences, which are the leading causes of death in the modern world. The pronounced age dependence of the manifestations of atherosclerosis pushes scientists to try to link the development of atherosclerosis with telomere length. The study of the role of telomere shortening in atherosclerosis is mainly limited to measuring the telomeres of blood cells, and only in rare cases (surgery or post-mortem examination) are the telomeres of local cells available for measurement. The review discusses the basic issues of cellular aging and the interpretation of telomere measurement data in atherosclerosis, as well as the prospects for the prevention and possible treatment of atherosclerosis.

CD166 promotes cancer stem cell-like phenotype via the EGFR/ERK1/2 pathway in the nasopharyngeal carcinoma cell line CNE-2R

AIMS

The present study aimed to investigate the role and underlying mechanisms of CD166 in cancer stem cell-like (CSCs) phenotype of the radioresistant nasopharyngeal carcinoma cell CNE-2R.

MAIN METHODS

Established CD166-shRNA- CNE-2R cell line by lentivirus-mediated silencing CD166. Then, CSC-related genes mRNAs and proteins, and EGFR/ERK1/2 signaling pathway were detected using RT-PCR and western blot. Sphere formation assay was performed to evaluate the sphere formation capacity in CD166-shRNA- CNE-2R cells. The tumorigenesis ability in vivo was examined in nude mice mode.

KEY FINDINGS

Downregulation of CD166 inhibited the expression of the CSC-related genes, pEGFR and pERK in vitro and vivo. The capacity to form spheres and tumorigenesis was significantly decreased in CD166-shRNA cells. Furthermore, EGF-stimulated CD166-shRNA cells exhibited an increase in CSC-like traits by activating EGFR/ERK1/2 signaling.

SIGNIFICANCE

CD166 induced CSCs formation by activating the EGFR/ERK1/2 signaling pathway in nasopharyngeal carcinoma, which may serve as a critical molecular target for NPC therapeutic strategies.

Silencing FAM135B enhances radiosensitivity of esophageal carcinoma cell

FAM135B (family with sequence similarity 135, member B) is related to the progression of esophageal squamous cell carcinoma (ESCC). However, the role played by the gene in radiosensitivity remains unknown. Herein, we examined the relationship between FAM135B and radiosensitivity. According to the results, FAM135B is highly expressed in ESCC cells, and ESCC cells with high levels of FAM135B are resistant to irradiation. Silencing FAM135B inhibits colony formation capability and cell cycle protein expression (pP53, CDK1), promotes cell cycle arrest at the G2/M phase following irradiation. Moreover, transcriptome sequencing analysis demonstrates that FAM135B regulates downstream PI3K/Akt/mTOR signaling pathway, and western blot verifies the result. One of the mechanisms of increasing radiosensitivity by silencing FAM135B expression in ESCC cells may be achieved by regulating the PI3K/Akt/mTOR signaling pathway. Silencing FAM135B shows synergy with PI3K/Akt/mTOR pathway inhibitor (rapamycin) in increasing radiosensitivity, regulating the expression of cell cycle protein and inducing apoptosis of ESCC cells. The results indicate that FAM135B could be a potential treatment target for ESCC in management of radiosensitivity.

Silencing hTERT attenuates cancer stem cell-like characteristics and radioresistance in the radioresistant nasopharyngeal carcinoma cell line CNE-2R

Objective: This study aimed to explore the effect of silencing hTERT on the CSC-like characteristics and radioresistance of CNE-2R cells.

Results: Silencing hTERT suppressed CNE-2R cell proliferation and increased the cell apoptosis rate and radiosensitivity in vitro. Moreover, it could also inhibit the growth of xenografts and increase the apoptosis index and radiosensitivity in vivo. Further study discovered that after silencing hTERT, telomerase activity in CNE-2R cells was markedly suppressed, along with remarkably down-regulated stem cell-related protein levels both in vitro and in vivo.

Conclusion: Silencing hTERT can suppress the CSC-like characteristics of CNE-2R cells to enhance their radiosensitivity, revealing that hTERT may become a potential target for treating radioresistant NPC.

Methods: An RNAi lentiviral vector specific to the hTERT gene was constructed to infect CNE-2R cells, the hTERT silencing effect was verified through qPCR and Western blot assays, and telomerase activity was detected by PCR-ELISA. Moreover, radiosensitivity in vitro was detected through colony formation assays, CCK-8 assays and flow cytometry. Tumor growth and radioresistance were also evaluated using xenograft models, while the apoptosis index in xenografts was measured through TUNEL assay. Levels of stem cell-related proteins were determined in vitro and in vivo.

The tumor-suppressive role of microRNA-873 in nasopharyngeal carcinoma correlates with downregulation of ZIC2 and inhibition of AKT signaling pathway

Cancer stem cells (CSCs) are responsible for tumor initiation, relapse, and metastasis. Thus, residual CSCs after chemotherapy may result in poor prognosis for nasopharyngeal carcinoma (NPC). Emerging evidence suggests that differentially expressed microRNAs (miRNAs) regulate genes that carry out important functions in CSCs. Here we investigate the interaction of microRNA-873 (miR-873) with the Zic family member 2 (ZIC2) and the effects on downstream serine-threonine protein kinase (AKT) signaling pathway in CSCs in the context of NPC. Initially, microarray-based gene expression profiling identified ZIC2 as a key differentially expressed gene in NPC, which was subsequently confirmed to be upregulated in clinical NPC tissue samples. NPC cells were subjected to sphere-formation conditions in low-attachment plates, followed by sorting of CD133⁺ cells, which were selected as NPC stem cells after further characterization of stem cell biomarkers. ZIC2 was then shown to be enriched in NPC stem cells at both mRNA and protein levels. However, loss of ZIC2 was associated with the self-renewal, proliferative and tumorigenic properties of NPC stem cells. Next, miRNAs potentially able to target ZIC2 were predicted by the intersection of mirDIP and TargetScan database results, and miRNA miR-873 was found to be downregulated in NPC tissues in general but especially in NPC stem cells. Upregulation of miR-873 inhibited the stem-like properties and tumorigenicity of NPC stem cells, which was found to take place through downregulation of ZIC2 and disruption of the AKT signaling pathway. Collectively, the results obtained suggest that overexpression of miR-873 could aid NPC tumor suppression through reduction of the malignant potential of CSCs.

Comparative Analysis of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells between Preeclampsia and Normal Pregnant Women

Preeclampsia is a syndrome characterized by deterioration of either the maternal condition or the fetal condition. The adverse intrauterine environment made by preeclampsia results into intrauterine growth restriction and increased risk of a variety of diseases in future life. Given the adverse environment of fetal circulation made in the preeclamptic condition, and the role of mesenchymal stem cell (MSC) as a multipotent progenitor cell, we hypothesized that MSCs derived from human umbilical cord blood (hUCB-MSCs) obtained from preeclampsia are adversely altered or affected compared with normal pregnancy. The aim of this study was to analyze the biological characteristics and compare the functional abilities and gene expression patterns of hUCB-MSCs originating from pregnant women with and without severe preeclampsia. hUCB-MSCs were isolated and cultured from 28 pregnant women with severe preeclampsia and 30 normal pregnant women. hUCB-MSCs obtained from women with preeclampsia were less proliferative and more senescent and had lower telomerase activity and higher ROS activity than cells from women with normal pregnancy. In addition, many senescence-related differentially expressed genes (DEGs) were identified by analysis of microarray gene expression profiles and significantly associated with the Gene Ontology term cell aging. In conclusion, hUCB-MSCs obtained from women with preeclampsia showed the poorly proliferative, more senescent, and decreased telomerase activity, and these characters may be related with functional impairment of MSC from preeclampsia compared with cells from normal pregnancy.

A positive feedback loop between Wnt/β-catenin signaling and hTERT regulates the cancer stem cell-like traits in radioresistant nasopharyngeal carcinoma cells

Radioresistance may be induced by cancer stem cells (CSCs), while the biological traits of CSCs need to be retained by telomerase. The telomerase activity mainly depends on the transcriptional regulation of human telomerase reverse transcriptase (hTERT). Moreover, Wnt/β-catenin signaling is also considered essential for maintaining the CSC phenotypes. In the previous study, we discovered that the radioresistant nasopharyngeal carcinoma cells CNE-2R displayed CSC-like traits, as well as high expression of hTERT and β-catenin, but whether hTERT and β-catenin were involved in regulating the CSC-like traits and radiosensitivity of CNE-2R cells remained unclear. In this study, our results suggested that hTERT could positively regulate the expression of CSC-related proteins, as well as the cytoplasm- and nucleus-β-catenin, but it could not markedly regulate the expression of total β-catenin in CNE-2R cells. Meanwhile, Wnt/β-catenin signaling had a positive regulatory effect on the expression of hTERT and CSC-related proteins. Moreover, there was a β-catenin/hTERT protein complex in CNE-2R cells, indicating that β-catenin could directly interact with hTERT protein. Our results also revealed that silencing hTERT or suppressing Wnt/β-catenin signaling could attenuate telomerase activity and radioresistance of CNE-2R cells; while suppressing Wnt/β-catenin signaling, the telomerase activity and radioresistance could be reversed through overexpressing hTERT. Taken together, we have outlined a positive feedback loop between Wnt/β-catenin signaling and hTERT in CNE-2R cells, which can regulate the telomerase activity and CSC-like traits, thus regulating the radiosensitivity. Therefore, blocking Wnt/β-catenin signaling transduction and interfering with hTERT expression may be a promising approach for targeting radioresistant nasopharyngeal carcinoma cells with CSC-like traits.

Cancer stem cells in esophageal squamous cell cancer

Cancer stem cells (CSCs) are hypothesized to govern the origin, progression, drug resistance, recurrence and metastasis of human cancer. CSCs have been identified in nearly all types of human cancer, including esophageal squamous cell cancer (ESCC). Four major methods are typically used to isolate or enrich CSCs, including: i) fluorescence-activated cell sorting or magnetic-activated cell sorting using cell-specific surface markers; ii) stem cell markers, including aldehyde dehydrogenase 1 family member A1; iii) side population cell phenotype markers; and iv) microsphere culture methods. ESCC stem cells have been identified using a number of these methods. An increasing number of stem cell signatures and pathways have been identified, which have assisted in the clarification of molecular mechanisms that regulate the stemness of ESCC stem cells. Certain viruses, such as human papillomavirus and hepatitis B virus, are also considered to be important in the formation of CSCs, and there is a crosstalk between stemness and viruses-associated genes/pathways, which may suggest a potential therapeutic strategy for the eradication of CSCs. In the present review, findings are summarized along these lines of inquiry.

Cancer stem cell-like characteristics and telomerase activity of the nasopharyngeal carcinoma radioresistant cell line CNE-2R

The radioresistance of nasopharyngeal carcinoma (NPC) may be related to cancer stem cells (CSCs), and the characteristics of CSCs may be maintained by telomerase activity. In this study, we explored the CSC‐like characteristics and telomerase activity of the NPC radioresistant cell line CNE‐2R. This work provides a foundation for future studies on stem cell‐targeted therapies by targeting the radioresistance of NPC. The expression of stem cell‐related genes/proteins and the hTERT gene/protein in CNE‐2R and its parent radiosensitive cell line CNE‐2 were detected using qPCR/Western Blot. Label‐retaining cells (LRCs) were detected through immunocytochemistry, and telomerase activity was detected using a PCR‐ELISA kit. CD133 expression was detected with flow cytometry. CNE‐2R‐CD133+ and CNE‐2R‐CD133− cells were separated with magnetic‐activated cell sorting. The proliferation and tumorigenesis capacities of CNE‐2R‐CD133+, CNE‐2R‐CD133−, and CNE‐2R cells were compared with a CCK‐8 assay, sphere formation assay, and an in vivo experiment. Our results showed that the expression of stem cell‐related genes and the hTERT gene in CNE‐2R cells was higher than those in CNE‐2 cells. Similarly, the expression of stem cell‐related proteins and the hTERT protein in CNE‐2R cells was markedly higher than those in CNE‐2 cells. The proportion of LRCs in CNE‐2R and CNE‐2 cells was (3.10 ± 0.63%) vs (0.40 ± 0.35%; P < 0.001), respectively. Telomerase activity in CNE‐2R cells was remarkably higher than that in CNE‐2 cells. Flow cytometry suggested that the CD133 positive rates in CNE‐2R and CNE‐2 cells were (2.49 ± 0.56%) vs (0.76 ± 0.25%; P = 0.008), respectively. Meanwhile, the proliferation capacity, tumorigenesis capacity, and telomerase activity of CNE‐2R‐CD133+ cells were notably higher than those of CNE‐2R‐CD133− and CNE‐2R cells. Collectively, CNE‐2R displayed CSC‐like characteristics; our results also showed that CNE‐2R cells, especially the sorted CSCs, had high telomerase activity levels.