Generation Of Cancer Stem Cells Research Articles

Proteoglycans Determine the Dynamic Landscape of EMT and Cancer Cell Stemness.

Proteoglycans (PGs) are pivotal components of extracellular matrices, involved in a variety of processes such as migration, invasion, morphogenesis, differentiation, drug resistance, and epithelial-to-mesenchymal transition (EMT). Cellular plasticity is a crucial intermediate phenotypic state acquired by cancer cells, which can modulate EMT and the generation of cancer stem cells (CSCs). PGs affect cell plasticity, stemness, and EMT, altering the cellular shape and functions. PGs control these functions, either by direct activation of signaling cascades, acting as co-receptors, or through regulation of the availability of biological compounds such as growth factors and cytokines. Differential expression of microRNAs is also associated with the expression of PGs and their interplay is implicated in the fine tuning of cancer cell phenotype and potential. This review summarizes the involvement of PGs in the regulation of EMT and stemness of cancer cells and highlights the molecular mechanisms.

Association between cancer stem cell gene expression signatures and prognosis in head and neck squamous cell carcinoma

BackgroundVarious cancer stem cell (CSC) biomarkers and the genes encoding them in head and neck squamous cell carcinoma (HNSCC) have been identified and evaluated. However, the validity of these factors in the prognosis of HNSCC has been questioned and remains unclear. In this study, we examined the clinical significance of CSC biomarker genes in HNSCC, using five publicly available HNSCC cohorts.MethodsTo predict the prognosis of patients with HNSCC, we developed and validated the expression signatures of CSC biomarker genes whose mRNA expression levels correlated with at least one of the four CSC genes (CD44, MET, ALDH1A1, and BMI1).ResultsPatients in The Cancer Genome Atlas (TCGA) HNSCC cohort were classified into CSC gene expression-associated high-risk (CSC-HR; n = 285) and CSC gene expression-associated low-risk (CSC-LR; n = 281) subgroups. The 5-year overall survival and recurrence-free survival rates were significantly lower in the CSC-HR subgroup than in the CSC-LR subgroup (p = 0.04 and 0.02, respectively). The clinical significance of the CSC gene expression signature was validated using four independent cohorts. Analysis using Cox proportional hazards models showed that the CSC gene expression signature was an independent prognostic factor of non-oropharyngeal HNSCC which mostly indicates HPV (–) status. Furthermore, the CSC gene expression signature was associated with the prognosis of HNSCC patients who received radiotherapy.ConclusionThe CSC gene expression signature is associated with the prognosis of HNSCC and may help in personalized treatments for patients with HNSCC, especially in cases with HPV (–) status who were classified in more detail.

Resistance to Trastuzumab.

Simple SummaryTrastuzumab is a humanized antibody that has significantly improved the management and treatment outcomes of patients with cancers that overexpress HER2. Many research groups, both in academia and industry, have contributed towards understanding the various mechanisms engaged by trastuzumab to mediate its anti-tumor effects. Nevertheless, data from several clinical studies have indicated that a significant proportion of patients exhibit primary or acquired resistance to trastuzumab therapy. In this article, we discuss underlying mechanisms that contribute towards to resistance. Furthermore, we discuss the potential strategies to overcome some of the mechanisms of resistance to enhance the therapeutic efficacy of trastuzumab and other therapies based on it.One of the most impactful biologics for the treatment of breast cancer is the humanized monoclonal antibody, trastuzumab, which specifically recognizes the HER2/neu (HER2) protein encoded by the ERBB2 gene. Useful for both advanced and early breast cancers, trastuzumab has multiple mechanisms of action. Classical mechanisms attributed to trastuzumab action include cell cycle arrest, induction of apoptosis, and antibody-dependent cell-mediated cytotoxicity (ADCC). Recent studies have identified the role of the adaptive immune system in the clinical actions of trastuzumab. Despite the multiple mechanisms of action, many patients demonstrate resistance, primary or adaptive. Newly identified molecular and cellular mechanisms of trastuzumab resistance include induction of immune suppression, vascular mimicry, generation of breast cancer stem cells, deregulation of long non-coding RNAs, and metabolic escape. These newly identified mechanisms of resistance are discussed in detail in this review, particularly considering how they may lead to the development of well-rationalized, patient-tailored combinations that improve patient survival.

Systematic molecular profiling of acute leukemia cancer stem cells allows identification of druggable targets

Acute myeloid leukemia (AML) is one of the most prevalent and acute blood cancers with a poor prognosis and low overall survival rate, especially in the elderly. Although several new AML markers and drug targets have been recently identified, the rate of long-term cancer eradication has not improved significantly due to the presence and drug resistance of AML cancer stem cells (CSCs). Here we develop a novel computational pipeline to analyze the transcriptomic profiles of AML cancer (stem) cells and identify novel candidate AML CSC markers and drug targets. In our novel pipeline we apply a top-down meta-analysis strategy to integrate The Cancer Genome Atlas data with CSC datasets to infer cell stemness features. As a result, a set of genes termed the “AML key CSC genes” along with all the available drugs/compounds that could target them were identified. Overall, our novel computational pipeline could retrieve known cancer drugs (Carfilzomib) and predicted novel drugs such as Zonisamide, Amitriptyline, and their targets amongst the top ranked drugs and drug targets for targeting AML. Additionally, the pipeline applied in this study could be used for the identification of CSC-specific markers, drivers and their respective targeting drugs in other cancer types.

Assessing Putative Markers of Colorectal Cancer Stem Cells: From Colonoscopy to Gene Expression Profiling.

Cancer stem cells (CSCs) are proposed to be involved in colorectal cancer (CRC) initiation, growth, and metastasis. The aim of our pilot study was to assess possible correlations between the clinicopathological characteristics of CRC patients and CSCs gene expression patterns, in order to provide insight into new methods for patient stratification and targeted therapeutic strategies. Our study involved 60 CRC patients, and the following three specific CSC genes were targeted: PROM1/CD133, ALCAM/CD166 and HCAM /CD44. Data are presented as relative mRNA expression of target genes to GAPDH. The expression of total CD133 and CD166 was assessed in paired samples of CRC tumors and adjacent tissue, while CD44 was assessed in similar samples. The qRT-PCR analysis detected all three targeted genes to different extents, in both normal and tumor tissue. In nine cases (15.69%), total CD133 had a higher expression in tumor tissue, whilst in 28 cases (47.06%) the expression was higher in non-malignant peritumor tissue. The total CD166 expression was increased in tumor tissue compared with paired non-invaded peritumor samples in eight cases (13.73%), whilst in eight cases (13.73%) the expression was higher in non-malignant peritumor tissue. Total CD44 expression was higher in tumor tissue compared with paired non-invaded peritumor samples in 47 cases (78.95%). In the remaining cases the difference between paired samples was biologically insignificant. In conclusion, our study suggests that qRT-PCR is feasible in assessing the gene expression profiles of CSCs from CRC, and a promising pathway to be followed for determining how often a person needs screening by colonoscopy and at which age to start. This could improve CRC diagnosis and early patient stratification, and open the way for new oncologic treatment development.

Identification of upregulated genes in glioblastoma and glioblastoma cancer stem cells using bioinformatics analysis

Glioblastoma (GBM) is the most common malignant brain tumor among adults. Cancer stem cells (CSCs) are known to drive treatment resistance and recurrence. However, a few CSC markers have been identified as therapeutic targets for GBM. This study aimed to show highly coexpressed genes in GBM CSCs and TCGA GBM samples and to identify possible therapeutic targets for GBM. The gene expression profiles of GBM CSCs were obtained from Gene Expression Omnibus database. After the differentially upregulated genes were screened, functional enrichment analyses were performed using DAVID and Reactome databases. For upregulated genes, biological processes were mainly associated with the regulation of transcription. Subsequently, a protein-protein interaction network was constructed for upregulated genes through STRING, in which DUSP6, FGFR3, EGFR, SOX2, NES, and PLP1 were further identified as hub genes via MCC and MNC methods. Expression profiles of hub genes and their association with survival were examined in TCGA GBM dataset using GEPIA2 platform. The expression levels of four hub genes were found to be increased in TCGA GBM samples. Of these, DUSP6 and SOX2 had prognostic value for patients with GBM. Molecular compounds targeting DUSP6 were searched through PubChem database. (E/Z)-BCI and BCI were found to be inhibitors of DUSP6. The molecular docking was performed using Autodock vina 1.02. The compounds showed strong binding capacities by forming various interactions with the ERK2 binding domain of DUSP6. Hence, the current study unravels the potential of (E/Z)-BCI and BCI compounds as possible anti-cancer molecules for GBM treatment.

The driver role of JAK-STAT signalling in cancer stemness capabilities leading to new therapeutic strategies for therapy- and castration-resistant prostate cancer.

BackgroundLineage plasticity in prostate cancer (PCa) has emerged as an important mechanism leading to the onset of therapy‐ and castration‐resistant PCa (t‐CRPC), which is closely associated with cancer stem cell (CSC) activity. This study is to identify critical driver(s) with mechanism of action and explore new targeting strategy.MethodsVarious PCa cell lines with different genetic manipulations were subjected to in vitro prostasphere assay, cell viability assay and in vivo stemness potential. In addition, bioinformatic analyses such as Ingenuity pathway and Gene Set Enrichment Analysis were carried out to determine clinical relevance. The in vivo anti‐tumour activity of JAK or STAT1 inhibitors was examined in clinically relevant t‐CRPC model.ResultsWe demonstrated the role of interferon‐related signalling pathway in promoting PCa stemness, which correlated with significant elevation of interferon related DNA damage resistance signature genes in metastatic PCa. Inhibition of JAK‐STAT1 signalling suppresses the in vitro and in vivo CSC capabilities. Mechanistically, IFIT5, a unique downstream effector of JAK‐STAT1 pathway, can facilitate the acquisition of stemness properties in PCa by accelerating the turnover of specific microRNAs (such as miR‐128 and ‐101) that can target several CSC genes (such as BMI1, NANOG, and SOX2). Consistently, knocking down IFIT5 in t‐CRPC cell can significantly reduce in vitro prostasphere formation as well as decrease in vivo tumour initiating capability.ConclusionsThis study provides a critical role of STAT1‐IFIT5 in the acquisition of PCSC and highlights clinical translation of JAK or STAT1 inhibitors to prevent the outgrowth of t‐CRPC.

Catulin reporter marks a heterogeneous population of invasive breast cancer cells with some demonstrating plasticity and participating in vascular mimicry

Breast cancer is the most commonly diagnosed cancer in women worldwide. The activation of partial or more complete epithelial–mesenchymal transition in cancer cells enhances acquisition of invasive behaviors and expands their generation of cancer stem cells. Increased by EMT plasticity of tumor cells could promote vascular mimicry, a newly defined pattern of tumor microvascularization by which aggressive tumor cells can form vessel-like structures themselves. VM is strongly associated with a poor prognosis, but biological features of tumor cells that form VM remains unknown. Here we show that catulin is expressed in human BC samples and its expression correlates with the tumor progression. Ablation of catulin in hBC cell lines decreases their invasive potential in the 3D assays. Using a novel catulin promoter based reporter we tracked and characterized the small population of invasive BC cells in xenograft model. RNAseq analysis revealed enrichment in genes important for cellular movement, invasion and interestingly for tumor-vasculature interactions. Analysis of tumors unveiled that catulin reporter marks not only invasive cancer cells but also rare population of plastic, MCAM positive cancer cells that participate in vascular mimicry. Ablation of catulin in the xenograft model revealed deregulation of genes involved in cellular movement, and adhesive properties with striking decrease in CD44 which may impact stemness potential, and plasticity of breast cancer cells. These findings show directly that some plastic tumor cells can change the fate into endothelial-like, expressing MCAM and emphasize the importance of catulin in this process and breast cancer progression.

Interferon signalling contributes to therapy‐resistant prostate cancer progression

Interferon signalling contributes to therapy‐resistant prostate cancer progression

Loss of exosomal miR-34c-5p in cancer-associated fibroblast for the maintenance of stem-like phenotypes of laryngeal cancer cells.

Cancer-associated fibroblasts (CAFs) reconstitute cancer stemness. This study aims to investigate whether the loss of CAF-derived exosomal miR-34c-5p contributes to the maintenance of stem-like properties of laryngeal squamous cell carcinoma (LSCC). Exosomes from primarily cultured CAFs and paired normal fibroblasts (NFs) were collected and identified. The differential expression of exosomal miR-34c-5p between CAFs and NFs was detected by next-generation sequencing. In vitro and in vivo assays were performed to examine the effects of miR-34c-5p on the maintenance of stem-like properties. MiR-34c-5p expression is significantly reduced in CAF-derived exosomes. In vitro and in vivo assays revealed that exosomal miR-34c-5p can regulate the stem-like properties of LSCC cells, such as proliferation, invasion, sphere and plate colony formation, chemoresistance, tumorigenicity in nude mice, as well as the expression of cancer stem cell genes. Loss of miR-34c-5p in CAF-derived exosomes contributes to the maintenance of stem-like phenotypes of LSCC.

RNA N6-methyladenosine modification in regulating cancer stem cells and tumor immune microenvironment and its implication for cancer therapy.

Therapy resistance is a well-known phenomenon in cancer treatment. It can be intrinsic or acquired, accountable for frequent tumor relapse and death worldwide. The interplay between cancer cells and their neighboring environment can activate complex signaling mechanisms influencing epigenetic changes and maintain cancer cell survival leading to the malignant phenotype. Cancer stem cells (CSCs) are tumor-initiating cells (TICs) and constitute the primary source of drug resistance and tumor recurrence. Studies have shown that cancer cells exhibit dysregulated RNA N6-methyladenosine (m6A) "writers," "erasers," and "readers" levels after acquiring drug resistance. The present review provides novel insight into the role of m6A modifiers involved in CSC generation, cancer cell proliferation, and therapy resistance. m6A RNA modifications in the cross-talk between CSC and the tumor immune microenvironment (TIME) have also been highlighted. Further, we have discussed the therapeutic potential of targeting m6A machinery for cancer diagnosis and the development of new therapies for cancer treatment.

Abstract 1523: Beta-2 adrenergic receptor and mu opioid receptor interact to increase the aggressiveness in triple negative breast cancer cells through activation of GSK3 signaling

Abstract Breast cancer is the world’s leading cause of cancer mortality in women worldwide. It has been shown that body stress hormones, such as norepinephrine, and opioid peptides interact to control the growth and progression of this cancer. Opioid and beta-adrenergic receptors are recently shown to cross talk via formation of receptor heterodimers to control cellular functions in various cell systems. However, the underlying cell signaling mechanism remains unclear. To determine the effect of the interaction of the two systems in breast cancer, we employed triple-negative breast cancer (TNBC) cell lines MDA-MB-231 and MDA-MB-468, CRISPR, chemical inhibition or activation and, PCR Array technology to study aggressive tumor phenotype and signaling cascades. We found that knock down of the beta-adrenergic (B2AR) or mu-opioidergic receptor (MOR) system via the CRISPR technique or pharmacological agents induces a less aggressive phenotype in triple negative breast cancer cells both in vitro and in vivo, with the effect being potentiated when both receptor systems were inhibited together. The mRNA expression study using a PCR Array targeting Cancer Stem Cell genes shows that B2AR or MOR activated the glycogen synthase kinase 3 (GSK3) signaling cascade. The GSK3 inactivation in MDA-MB-231 and MDA-MB-468 cells induced similar phenotypic changes as was done by the inhibition of B2AR and/or MOR, while a GSK3 activation by wortmannin reversed the effects of B2AR and/or MOR knockdown on these cells. GSK3 inactivation also prevents B2AR agonist norepinephrine or MOR agonist DAMGO from affecting MDA-MB-231 and MDA-MB-468 cell proliferation. These data identify a role of B2AR and MOR interaction in the control of breast cancer cell growth and establish a possible role of the GSK3 signaling system in mediation of these two receptors’ cross talk. (Supported by NIH grant R01 CA20863201). Citation Format: Bénédicte Rousseau, Sengottuvelan Murugan, Ajay Palagani, Dipak K. Sarkar. Beta-2 adrenergic receptor and mu opioid receptor interact to increase the aggressiveness in triple negative breast cancer cells through activation of GSK3 signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1523.

Abstract 6064: ADAR1-dependent RNA editing of GLI1 drives hepatocellular carcinoma stem cell self-renewal by initiating mitophagy

Abstract Background: Hepatocellular carcinoma (HCC) is one of the most common and most difficult to cure malignancies worldwide. Identifying new effective therapeutic targets is of great significance for the management of HCC. Cumulative evidence suggests cancer stem cells (CSCs) are key drivers of tumor growth and heterogeneity. Post-transcriptional RNA editing of adenosine to inosine (A-to-I) catalyzed by ADAR1 dramatically alters cellular transcriptome in cancers. However, ADAR1 editase-dependent mechanisms governing hepatic CSC generation have not been elucidated. Therefore, we have systematically and comprehensively investigated ADAR1’s effect on CSC self-renewal in HCC. Methods: An in vitro human hepatocyte differentiation model along with relevant transcriptomic data form GEO and TCGA were analyzed to characterize the oncofetal role of ADAR1. Using genetic approaches, RNA sequencing was performed to identify putative ADAR1-mediated recoding edited genes in HCC cell lines. Clinical implication of GLI1 editing was studied in a cohort of 88 HCC patients. GLI1 editing-mediated change in its promoter activity and protein stability was investigated by dual reporter assay, CHIP, Co-IP, and PLA assays. Functional difference in stemness properties, including abilities of self-renewal, differentiation, tumorigenesis, chemo-resistance and metastasis between wild-type and edited GLI1 (GLI1wt vs. GLI1R701G) and the exact mechanisms were also studied in cell models and mice. Results: Lentiviral ADAR1 wild-type but not editing-defective ADAR1E912A mutant, editing at nt2101 of GLI1 transcript caused arginine-to-glycine substitution at the residue 701. Importantly, increased editing of GLI1 was implicated in the pathogenesis of HCC. Upon editing, C-terminal half of GLI1 harbored a lower susceptibility to the inhibition of SUFU, thus promoting its nuclear translocation and activation. Moreover, GLI1R701G appeared more stable than GLI1wt due to reduced formation of specific K63-GLI1 substrate and β-TrCP-GLI1 complex. Edited GLI1 was found to strongly enhance targeted activation of NANOG and SOX9, resulting in accumulation of hepatic CSCs population, hepatocarcinogenesis, sorafenib-resistance and metastasis. Additionally, GLI1 editing initiated mitophagy via PINK1/Parkin-dependent pathway. Impaired mitophagy effectively antagonized the functions of GLI1R701G on hepatic CSC self-renewal and overcome chemoresistance. Conclusion: The critical advance of this study is that ADAR1 editase activity drives GLI1-dependent maintenance of the hepatic CSC population. Our discovery of a pivotal ADAR1-GLI1-PINK1 self-renewal axis provides the first mechanistic link between RNA-editing-driven malignant progression and mitochondrial homeostasis. Thus, ADAR1 represents a unique therapeutic vulnerability in liver CSCs with active mitophagy mediated by edited GLI1. Citation Format: Jie Luo, Lanqi Gong, Yuma Yang, Jiao Huang, Xiaona Fang, Baifeng Zhang, Ying Tang, Beilei Liu, Ming Liu, Lu Bai, Victor Ho-Fun Lee, Xin-Yuan Guan. ADAR1-dependent RNA editing of GLI1 drives hepatocellular carcinoma stem cell self-renewal by initiating mitophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6064.

A Phase 1 Proof of Concept Study Evaluating the Addition of an LSD1 Inhibitor to Nab-Paclitaxel in Advanced or Metastatic Breast Cancer (EPI-PRIMED).

ObjectiveLysine-Specific Demethylase-1 (LSD1) is overexpressed in breast cancer cells and facilitate mesenchymal properties which may contribute to therapeutic resistance and cancer progression. The purpose of this study was to investigate the safety of combination, nab-paclitaxel and phenelzine, an irreversible LSD1 inhibitor in patients with metastatic breast cancer (mBC).MethodsEligible patients with mBC were treated with nab-paclitaxel (100mg/m2) weekly for 3 weeks with one week break in a 28-day cycle. Dose escalation of phenelzine followed the Cumulative Cohort Design and phenelzine treatment commenced from day 2 of first cycle. Eleven patients were screened, and eligible patients were enrolled in cohorts with the dose of phenelzine ranging from 45mg to 90mg.ResultsThe Optimum Biological Dose was established at 60mg of phenelzine daily in combination with nab-paclitaxel and considered as the recommended phase 2 dose. Most (95%) of adverse events were grade 1 or 2 with two grade 3 events being diarrhea and neutropenia at 45mg and 60mg phenelzine respectively, with no unexpected toxicity/deaths. Commonly reported toxicities were fatigue (n=4,50%), dizziness (n=6,75%), neutropenia (n=3,37.5%), peripheral neuropathy (n=3,37.5%), diarrhea (n=2,25%), and hallucination (n=2,25%). After a median follow up of 113 weeks, all patients showed disease progression on trial with 4 patients being alive at the time of data cut off, including one patient with triple negative breast cancer. Median progression-free survival was 34 weeks. Significant inhibition of LSD1 and suppression of mesenchymal markers in circulating tumor cells were noted.ConclusionPhenelzine in combination with nab-paclitaxel was well tolerated, without any unexpected toxicities in patients with mBC and demonstrated evidence of antitumor activity. For the first time, this proof-of-concept study showed in-vivo inhibition of LSD1 suppressed mesenchymal markers, which are known to facilitate generation of cancer stem cells with metastatic potential. Clinical Trial Registration: ClinicalTrials.Gov NCT03505528, UTN of U1111-1197-5518.

A Functional Screening Identifies a New Organic Selenium Compound Targeting Cancer Stem Cells: Role of c-Myc Transcription Activity Inhibition in Liver Cancer.

Cancer stem cells (CSCs) are reported to play essential roles in chemoresistance and metastasis. Pathways regulating CSC self‐renewal and proliferation, such as Hedgehog, Notch, Wnt/β‐catenin, TGF‐β, and Myc, may be potential therapeutic targets. Here, a functional screening from the focused library with 365 compounds is performed by a step‐by‐step strategy. Among these candidate molecules, phenyl‐2‐pyrimidinyl ketone 4‐allyl‐3‐amino selenourea (CU27) is chosen for further identification because it proves to be the most effective compound over others on CSC inhibition. Through ingenuity pathway analysis, it is shown CU27 may inhibit CSC through a well‐known stemness‐related transcription factor c‐Myc. Gene set enrichment analysis, dual‐luciferase reporter assays, expression levels of typical c‐Myc targets, molecular docking, surface plasmon resonance, immunoprecipitation, and chromatin immunoprecipitation are conducted. These results together suggest CU27 binds c‐Myc bHLH/LZ domains, inhibits c‐Myc‐Max complex formation, and prevents its occupancy on target gene promoters. In mouse models, CU27 significantly sensitizes sorafenib‐resistant tumor to sorafenib, reduces the primary tumor size, and inhibits CSC generation, showing a dramatic anti‐metastasis potential. Taken together, CU27 exerts inhibitory effects on CSC and CSC‐associated traits in hepatocellular carcinoma (HCC) via c‐Myc transcription activity inhibition. CU27 may be a promising therapeutic to treat sorafenib‐resistant HCC.

A paediatric dysembryoplastic neuroepithelial tumour (DNET) with deregulated stem cell markers: a case report

BackgroundDysembryoplastic neuroepithelial tumours (DNETs) are rare, with only a few reported lethal cases. Currently, there are focused efforts by neuro-oncology professionals to reveal the molecular characterisations of individual central nervous system tumours (CNSTs). Here, we report the status of cancer stem cell (CSC) genes associated with resilience and drug resistance in a paediatric DNET, since the deregulations and variations of CSC genes may prove critical to these tumours’ molecular characterisations.Case DescriptionImmunofluorescence, clonogenic assay and whole exome sequencing (WES) were applied to the patient’s tissue and its corresponding cell line. The case is for of a 6-year-old boy with intractable epilepsy and unremarkable physical and neurological examinations. Following magnetic resonance imaging (MRI) and histopathological tests, the patient was diagnosed with DNET. The child underwent a right posterior temporoparietooccipital neuronavigation-assisted craniotomy. Several CSC markers were upregulated in situ, including the metastasis-related protein, anterior gradient 2 (AGR2; 67%), and the Wnt-signalling-related protein, frizzled class receptor 9 (FZD9; 79%). The cell line possessed a similar DNA profile as the original tissue, stained positive for the tumorigenic marker [BMI1 proto-oncogene (BMI)] and CSC markers, and displayed drug resistance. Variants identified in the tissue DNA, which are listed in the catalogue of somatic mutations in cancer (COSMIC) database for genes previously known to be necessary for the development of the embryonic brain, included variants in the cell division cycle 27 (CDC27) gene.Conclusionswe report the in situ and in vitro presence of CSCs in a paediatric DNET.

ΔNp63α mediates sulforaphane suppressed colorectal cancer stem cell properties through transcriptional regulation of Nanog/Oct4/Sox2

Cancer stem cells (CSCs) play a key role in cancer initiation, development, metastasis, and recurrence. Previously, we found that sulforaphane (SFN), a natural compound obtained from cruciferous vegetables, inhibited colorectal CSCs via the downregulation of TAp63α. However, the role of ΔNp63α, another critical isoform of p63 which has been considered to contribute to cancer progression, in SFN-mediated colorectal CSCs inhibition remains unclear. Here, we showed that ΔNp63α expression was enhanced in sphere-forming colorectal cancer cells. Overexpression of ΔNp63α promoted the properties of CSCs, while downregulation of ΔNp63α suppressed those properties. Besides, ΔNp63α was found to activate the transcription of core CSCs genes including Nanog, Oct4, and Sox2. Furthermore, in vitro and in vivo experiments illustrated the regulatory effects of SFN on ΔNp63α and colorectal CSCs. These findings suggested for the first time that ΔNp63α activated the transcription of Nanog, Oct4, Sox2 and mediated the interventional effects of SFN on colorectal CSCs, thus providing a novel mechanism by which SFN inhibits colorectal CSCs.

A Novel Estrogen Receptor β Agonist Diminishes Ovarian Cancer Stem Cells via Suppressing the Epithelial-to-Mesenchymal Transition.

Simple SummaryEstrogen receptors α (ERα) and β (ERβ) show distinct contributions to tumor initiation and progression. Given that ERβ mainly functions as a “tumor suppressor”, activation of ERβ using its specific agonist should be able to inhibit tumor progression. In this study, we show that a newly developed ERβ agonist, OSU-ERb-12, can not only impede ovarian cancer cell expansion and tumor growth but also reduce the cancer stem cell (CSC) population. OSU-ERb-12 could inhibit epithelial-to-mesenchymal transition (EMT) in ovarian cancer cells by increasing Snail expression, thereby, blocking EMT-mediated cancer cell dedifferentiation. We also found that OSU-ERb-12 inhibits ovarian cancer expansion in an ERα-independent manner while limiting the CSC population in an ERα-dependent manner. Taken together, our data suggest that the newly developed ERβ agonist OSU-ERb-12 can be used not only to hinder tumor growth but also has the potential to prevent tumor relapse and metastasis by depleting CSCs.Epithelial ovarian cancer is the most lethal malignancy of the female reproductive tract. A healthy ovary expresses both Estrogen Receptor α (ERα) and β (ERβ). Given that ERα is generally considered to promote cell survival and proliferation, thereby, enhancing tumor growth, while ERβ shows a protective effect against the development and progression of tumors, the activation of ERβ by its agonists could be therapeutically beneficial for ovarian cancer. Here, we demonstrate that the activation of ERβ using a newly developed ERβ agonist, OSU-ERb-12, can impede ovarian cancer cell expansion and tumor growth in an ERα-independent manner. More interestingly, we found that OSU-ERb-12 also reduces the cancer stem cell (CSC) population in ovarian cancer by compromising non-CSC-to-CSC conversion. Mechanistically, we revealed that OSU-ERb-12 decreased the expression of Snail, a master regulator of the epithelial-to-mesenchymal transition (EMT), which is associated with de novo CSC generation. Given that ERα can mediate EMT and facilitate maintenance of the CSC subpopulation and that OSU-ERb-12 can block the transactivity of ERα, we conclude that OSU-ERb-12 reduces the CSC subpopulation by inhibiting EMT in an ERα-dependent manner. Taken together, our data indicate that the ERβ agonist OSU-ERb-12 could be used to hinder tumor progression and limit the CSC subpopulation with the potential to prevent tumor relapse and metastasis in patients with ovarian cancer.

Ex vivo Optimization of Glucose-Regulated Protein 94/Glycoprotein 96 Expressions in Mammospheres; Implication for Breast Cancer Immunotherapy.

Objective The induction of immunity against cancer stem cells (CSCs) can boost the efficiency of cancer vaccines. Heat shock proteins (HSPs) are required for the successful activation of anti-tumor immune responses. Glycoprotein 96 (gp96) is a well-known HSP that promotes the cross-presentation of tumor antigens. The aim of the present study was to optimize the temperature for induction of gp96 in grade 3 breast cancer spheres. Materials and Methods In the experimental study, CSCs were enriched from breast tumor tissue samples and cultured in DMEM-F12 with epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), B27, and bovine serum albumin (BSA) for 22 days. The expression level of CD24 and CD44 as CSC markers was measured by flow cytometry in secondary mammospheres, and the expression of NANOG, SOX2, and OCT4 genes in CSCs was also analyzed using the real-time polymerase chain reaction (PCR). To find the optimal temperature regulation of gp96, the mammosphere was incubated at different temperatures for 1 hour, and gp96 expression was measured using the western blotting assay. Results Primary mammospheres were obtained after seven days of culture, and secondary spheres formed 22 days after passage. Flow cytometry analysis showed that cells with CD24-CD44+phenotype were enriched in the culture period (from 2.6% on day 1 to 32.6% on day 22). Real-time PCR indicated that OCT4, NANOG, and SOX2 expression in mammospheres were increased by 3.8 ± 0.6, 17.8 ± 0.6, and 7.7 ± 0.8 fold respectively in comparison to the MCF-7 cell line. Western blot analysis showed that gp96 production was significantly upregulated when mammospheres were incubated at both 42°C and 43°C in comparison to the control group. ConclusionAltogether, we found that heat-induced upregulated expression of gp96 in CSCs enriched mammospheres from breast tumor tissue might be used as a complementary procedure to generate more immunogenic antigens in immunotherapy settings.

Role of Nrf2 Signaling Cascade in Breast Cancer: Strategies and Treatment.

Breast cancer is the second leading cancer among all types of cancers. It accounts for 12% of the total cases of cancers. The complex and heterogeneous nature of breast cancer makes it difficult to treat in advanced stages. The expression of various enzymes and proteins is regulated by several molecular pathways. Oxidative stress plays a vital role in cellular events that are generally regulated by nuclear factor erythroid 2-related factor 2 (Nrf2). The exact mechanism of Nrf2 behind cytoprotective and antioxidative properties is still under investigation. In healthy cells, Nrf2 expression is lower, which maintains antioxidative stress; however, cancerous cells overexpress Nrf2, which is associated with various phenomena, such as the development of drug resistance, angiogenesis, development of cancer stem cells, and metastasis. Aberrant Nrf2 expression diminishes the toxicity and potency of therapeutic anticancer drugs and provides cytoprotection to cancerous cells. In this article, we have discussed the attributes associated with Nrf2 in the development of drug resistance, angiogenesis, cancer stem cell generation, and metastasis in the specific context of breast cancer. We also discussed the therapeutic strategies employed against breast cancer exploiting Nrf2 signaling cascades.