Migration Of Cancer Stem Cells Research Articles

Inhibition of Lung Cancer Stem Cell Migration and Growth Through Nano-Photodynamic Therapy

Inhibition of Lung Cancer Stem Cell Migration and Growth Through Nano-Photodynamic Therapy

Anti-ENO1 antibody combined with metformin against tumor resistance: a novel antibody-based platform.

Antibody-based platforms (i.e., ADC) have emerged as one of the most encouraging tools for the cancer resistance caused by cancer stem cells (CSCs) enrichment. Our study might provide a promising therapeutic direction against drug resistance and serve as a potential precursor platform for screening ADC. The cell migration, invasion, drug resistance, and self-renewal were assessed by the cell invasion and migration assay, wound healing assay, CCK-8 assay, colony formation assay, and sphere formation assay, respectively. The expression profiles of CSCs (ALDH+ and CD44+) subpopulations were screened by flow cytometry. The western blot and cell immunofluorescence assay were used to evaluate pathway-related protein expression in both anti-ENO1 antibody, MET combined with DPP/CTX-treated CSCs. In the present study, western blot and flow cytometry verified that anti-ENO1 antibody target the CD44+ subpopulation by inhibiting the PI3K/AKT pathway, while metformin might target the ALDH+ subpopulation through activation of the AMPK pathway and thus reverse drug resistance to varying degrees. Subsequently, in vitro investigation indicated that anti-ENO1 antibody, metformin combined with cisplatin/cetuximab could simultaneously target ALDH+ and CD44+ subpopulations. The combination also inhibited the CSCs proliferation, migration, invasion, and sphere formation; which may result in overcoming the drug resistance. Then, molecular mechanism exploration verified that the anti-ENO1 antibody, metformin combined with cisplatin/cetuximab inhibited the Wnt/β-catenin signaling. The study preliminarily revealed anti-ENO1 antibody combined with metformin could overcome drug resistance against CSCs by inhibiting the Wnt//β-catenin pathway and might serve as a potential precursor platform for screening ADC. More importantly, it is reasonably believed that antibody-based drug combination therapy might function as an encouraging tool for oncotherapy.

Circular RNA hsa_circ_0051246 acts as a microRNA-375 sponge to promote the progression of gastric cancer stem cells via YAP1.

Gastric cancer (GC) stem cells play an important role in GC progression. Circular RNAs (circRNAs) act as microRNA (miRNA) sponges and inhibit the biological function of miRNAs in GC cytoplasm. MiRNAs also participate in GC progress. circ_0051246 was shown to be associated with miR-375 after analyzing GC microarray data GSE78091 and GSE83521. The oncoprotein Yes-associated protein 1 (YAP1) is targeted by miR-375 and can be inactivated via the Hippo tumor suppressor pathway. Due to insufficient research on circ_0051246, this study aimed to investigate its relationship with miR-375 and YAP1 in cancer stem cells (CSCs). SGC-7901 CSCs were used to establish knockdown/overexpression models of circ_0051246, miR-375, and YAP1. Malignant phenotypes of CSCs were assessed using Cell Counting Kit 8, colony/sphere formation, 5-Ethynyl-2'-deoxyuridine assay, flow cytometry, Transwell, and wound healing assays. To detect the interactions between circ_0051246, miR-375, and YAP1 in CSCs, a dual-luciferase reporter assay and fluorescence in situ hybridization were performed. In addition, 24 BALB/c nude mice were used to establish orthotopic xenograft tumor models. Four groups of mice were injected with CSCs (1 × 106 cells/100 µL) with circ_0051246 knockdown, miR-375 overexpression, or their respective control cells, and tumor progression and gene expression were observed by hematoxylin-eosin staining, immunohistochemistry. Western blot and quantitative real-time PCR were utilized to examine protein and gene expression, respectively. Circ_0051246 silencing reduced viability, promoted apoptosis, and inhibited proliferation, migration and invasion of CSCs. The functional effects of miR-375 mimics were comparable to those of circ_0051246 knockdown; however, the opposite was observed after miR-375 inhibitors treatment of CSCs. Furthermore, circ_0051246-overexpression antagonized the miR-375 mimics' effects on CSCs. Additionally, YAP1 overexpression promoted CSC features, such as self-renewal, migration, and invasion, inhibited apoptosis and E-cadherin levels, and upregulated the expression of N-cadherin, vimentin, YAP1, neurogenic locus notch homolog protein 1, and jagged canonical notch ligand 1. Conversely, YAP1-silenced produced the opposite effect. Moreover, miR-375 treatment antagonized the malignant effects of YAP1 overexpression in CSCs. Importantly, circ_0051246 knockdown and miR-375 activation suppressed CSC tumorigenicity in vivo. This study highlights the promotion of circ_0051246-miR-375-YAP1 axis activation in GC progression and provides a scientific basis for research on the molecular mechanism of CSCs.

Abstract 459: Targeting the non-junctional tumorigenic function of connexin43 in cancer cell plasticity

Abstract Tumors are highly heterogeneous and dynamic, with both cancer cells and cancer stem cells (CSCs) displaying a high degree of plasticity contributing to metastasis and tumor recurrence following treatment. Epithelial-mesenchymal transition (EMT) enables cancer cells to acquire migratory and invasive characteristics, access the circulatory system, and metastasize. Moreover, EMT is associated with therapeutic resistance and CSC generation. Our previous research demonstrated a redistribution of the gap junction protein connexin43 (Cx43) from the plasma membrane to the cytosol during EMT. Using super-resolution STochastic Optical Reconstruction Microscopy (STORM), we have recently identified increased interaction of such intracellular Cx43 with microtubules during EMT and in primary glioblastoma (GBM) CSCs (GSCs). We further report a tumorigenic function for cytosolic Cx43/microtubule complexing in cancer cell and CSC proliferation, migration, and survival. Cx43 localization and activity is regulated by multiple sites for protein-protein interaction within the Cx43 carboxy-terminus (CT), including a tubulin binding domain. We employed a Cx43 mimetic peptide named JM2 (juxtamembrane 2) encompassing the microtubule binding sequence of the Cx43 CT. Following administration, JM2 efficiently and specifically disrupts the interaction of Cx43 with microtubules, inhibits GSC-derived neurosphere formation in vitro, and patient GBM-derived organoid growth ex vivo. Using an orthotopic GBM patient derived xenograft mouse model, we demonstrate in vivo that JM2 significantly decreases the number of GSCs within brain tumors, inhibits the formation of highly invasive GBM tumors, and increases mouse survival in combination with the chemotherapy alkylating agent temozolomide. Further examining the role of Cx43/microtubule complexing in the context of metastatic disease, we observed JM2 also decreases mesenchymal marker expression and inhibits cell migration and invasion in EMT models. Using an in vivo orthotopic breast cancer mouse model we find that intratumoral administration of JM2 prevents metastasis, significantly decreasing cancer cell lung colonization. Our findings validate targeting Cx43 complexing with microtubules, with JM2, as a novel therapeutic approach for cancer treatment through inhibition of EMT-associated increases in invasion and metastasis, and elimination of CSCs. Modulation of non-junctional Cx43 functions therefore represents a viable therapeutic approach to target cellular plasticity with broad therapeutic implications for many cancers. Citation Format: Samy Lamouille, Christina E. Wheeler, Stacie E. Deaver, Michael J. Zeitz, Zhi Sheng, Robert G. Gourdie, James W. Smyth. Targeting the non-junctional tumorigenic function of connexin43 in cancer cell plasticity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 459.

Abstract 2450: Transforming intestinal stem cells into metastatic cancer Stem cells by aberrantly activated cytokine-STAT5A signaling

Abstract Background: Lgr5 intestinal stem cells (ISC) are augmented by colorectal (CRC), but it is not clear if the aberrant Lgr5 ISCs result in the metastatic phenotypes of CRC, suggesting that epistasis-involved mutations in CRC suppressor genes or oncogene control Lgr5 ISC transformation into cancer stem cells (CSC). Somatic mutations in STAT5A or B are highly associated with CRC. Cytokine-STAT5 action is essential for Lgr5 ISC stemness, and enhanced STAT5 phosphorylation can induce Lgr5 ISC differentiation into secretory niche cells. Using human and mouse tumoroids, and organoid xerograph models, we aim to determine the effects of STAT5 oncogenic activation on Lgr5 ISC malignant and metastatic phenotypes. Methods: Colorectal surgical specimen from CRC and hepatic metastatic CRC patients were collected to perform RNAseq or single cell RNAseq (scRNAseq) analysis. Compound-mutant mice with STAT5 loss or gain of function in Apcmin+/- mice, were generated by crossing Apcmin+/- mice with Lgr5CreER and Rs26CreER, and Stat5f/f (loss of function of Stat5) or icS5f/f (gain of function of STAT5A) mice. CRISPR/Cas9 gene editing was applied to engineer APC mutations in human epithelial cell lines or Apc mutations in Lgr5 ISCs. Apc-mutant Lgr5 ISCs or tumoroids from Apcmin+/- mice combined with STAT5 loss or gain of function were differentiated, then were under intra-abdominal xenotransplantation. APC-mutant intestinal epithelial cell lines were used to determined CSC migration in the presence of STAT5 activation. STAT5 inhibitors were used to treat Apcmin+/- mice or tumoroids. Results: Human subject studies revealed that hepatic metastatic CRC patients exhibited the robustly increased STAT5A and/or Lgr5 colonic cancer cells. Murine studies showed that constitutively STAT5A activation (Ca-pYSTAT5) in colonic Apcmin+/- CSCs promoted CSC migration, invasion and metastasis. In vivo migration assay showed that transient STAT5A activation in the APC-mutant intestinal epithelia accelerated the migration of APC-mutant epithelia. Ex Vivo tumoroid xenotransplantation showed that Ca-pYSTAT5 resulted in tumoroid invasion into liver. Lineage tracing analysis showed that Ca-pYSTAT5 expanded Lgr5 CSCs in tumoroids and drove Lgr5 CSCs to hepatic metastasis. Importantly, Stat5 deletion in Lgr5 ISCs abolishes colon cancer orgnoids invasion. Pharmacological inhibition of STAT5 dimerization leads to Lgr5 cancer organoid degeneration and partially annihilated intestinal adenoma in Apcmin+/-. CHIP-seq analysis showed that Ca-pYSTAT5 increased an aberrant high level of Bcl6 expression by inducing super-enhancer activation in the Bcl-6 locus. Conclusion: Aberrantly activated Cytokine-STAT5A signaling is required for ISC malignancy and CSC hepatic metastasis. STAT5 blockade could be important to impair CRC metastasis. Citation Format: Haifeng Li, Wen Gao, Ruixue Liu, Xiaonan Han. Transforming intestinal stem cells into metastatic cancer Stem cells by aberrantly activated cytokine-STAT5A signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2450.

Differential contractility regulates cancer stem cell migration

Cancer stem cells (CSCs) are known to have a high capacity for tumor initiation and the formation of metastases. We have previously shown that in collagen constructs mimetic of aligned extracellular matrix architectures observed in carcinomas, breast CSCs demonstrate enhanced directional and total motility compared with more differentiated carcinoma populations. Here, we show that CSCs maintain increased motility in diverse environments including on 2D elastic polyacrylamide gels of various stiffness, 3D randomly oriented collagen matrices, and ectopic cerebral slices representative of a common metastatic site. A consistent twofold increase of CSC motility across platforms suggests a general shift in cell migration mechanics between well-differentiated carcinoma cells and their stem-like counterparts. To further elucidate the source of differences in migration, we demonstrate that CSCs are less contractile than the whole population (WP) and develop fewer and smaller focal adhesions and show that enhanced CSC migration can be tuned via contractile forces. The WP can be shifted to a CSC-like migratory phenotype using partial myosin II inhibition. Inversely, CSCs can be shifted to a less migratory WP-like phenotype using microtubule-destabilizing drugs that increase contractility or by directly enhancing contractile forces. This work begins to reveal the mechanistic differences driving CSC migration and raises important implications regarding the potentially disparate effects of microtubule-targeting agents on the motility of different cell populations.

Contractility and migration: New directions in cancer stem cell migration

Contractility and migration: New directions in cancer stem cell migration

The Emergence of Cancer Stem Cells in Early Diagnosed Prostate Cancer

The Emergence of Cancer Stem Cells in Early Diagnosed Prostate Cancer

Folic acid depletion as well as oversupplementation helps in the progression of hepatocarcinogenesis in HepG2 cells

Folate ingestion below and above the physiologic dose has been shown to play a tumorigenic role in certain cancers. Also, excessive folate supplementation after establishment of pre-established lesions led to an advancement in the growth of a few tumors. However, such information has not yet been achieved in the case of HCC. In our study, HepG2 cells were administered with three different concentrations of folic acid i.e. folic acid normal (FN) (2.27 µM), folic acid deficient (FD) (no folic acid), folic acid oversupplementation (FO) (100 µM) for 10 days. Intracellular folate levels were assayed by Elecsys Folate III kit based method. The migratory and invasive abilities were estimated by transwell migration and matrigel invasion methods respectively. FACS was done to evaluate cell viability and apoptosis. Agarose-coated plates were used to access cancer stem cells (CSCs) number. Quantitative RT-PCR and western blotting approaches were used for gene and protein expression of certain tumor suppressor genes (TSGs), respectively. FD cells depicted increased migration, invasion, apoptosis, necrosis and decreased cell viability, CSCs. On the other hand, FO cells showed increased migration, invasion, cell viability and number of CSCs and decreased apoptosis and necrosis. TSGs revealed diminished expression with both FA modulations with respect to FN cells. Thus, FA deficiency as well as abundance enhanced the HCC progression by adapting different mechanisms.

Selectively Targeting Breast Cancer Stem Cells by 8-Quinolinol and Niclosamide.

Cancer maintenance, metastatic dissemination and drug resistance are sustained by cancer stem cells (CSCs). Triple negative breast cancer (TNBC) is the breast cancer subtype with the highest number of CSCs and the poorest prognosis. Here, we aimed to identify potential drugs targeting CSCs to be further employed in combination with standard chemotherapy in TNBC treatment. The anti-CSC efficacy of up to 17 small drugs was tested in TNBC cell lines using cell viability assays on differentiated cancer cells and CSCs. Then, the effect of 2 selected drugs (8-quinolinol -8Q- and niclosamide -NCS-) in the cancer stemness features were evaluated using mammosphere growth, cell invasion, migration and anchorage-independent growth assays. Changes in the expression of stemness genes after 8Q or NCS treatment were also evaluated. Moreover, the potential synergism of 8Q and NCS with PTX on CSC proliferation and stemness-related signaling pathways was evaluated using TNBC cell lines, CSC-reporter sublines, and CSC-enriched mammospheres. Finally, the efficacy of NCS in combination with PTX was analyzed in vivo using an orthotopic mouse model of MDA-MB-231 cells. Among all tested drug candidates, 8Q and NCS showed remarkable specific anti-CSC activity in terms of CSC viability, migration, invasion and anchorage independent growth reduction in vitro. Moreover, specific 8Q/PTX and NCS/PTX ratios at which both drugs displayed a synergistic effect in different TNBC cell lines were identified. The sole use of PTX increased the relative presence of CSCs in TNBC cells, whereas the combination of 8Q and NCS counteracted this pro-CSC activity of PTX while significantly reducing cell viability. In vivo, the combination of NCS with PTX reduced tumor growth and limited the dissemination of the disease by reducing circulating tumor cells and the incidence of lung metastasis. The combination of 8Q and NCS with PTX at established ratios inhibits both the proliferation of differentiated cancer cells and the viability of CSCs, paving the way for more efficacious TNBC treatments.

The Extracellular Matrix: A Key Accomplice of Cancer Stem Cell Migration, Metastasis Formation, and Drug Resistance in PDAC.

Simple SummaryThis review takes the extracellular matrix (ECM) as the starting point, and describes its influence and related mechanisms on the biological behavior of pancreatic ductal carcinoma (PDAC). It focuses on how the ECM regulates cancer stem cells and thus affects the metastasis and drug resistance of PDAC. Finally, current and ongoing treatment strategies for ECM are presented. ECM-related factors and mechanisms are both the focus and difficulty of current therapeutic strategy research, but further exploration is crucial for effectively eradicating the disease and improving patient survival.Pancreatic ductal adenocarcinoma (PDAC) is rich in dense fibrotic stroma that are composed of extracellular matrix (ECM) proteins. A disruption of the balance between ECM synthesis and secretion and the altered expression of matrix remodeling enzymes lead to abnormal ECM dynamics in PDAC. This pathological ECM promotes cancer growth, survival, invasion, and alters the behavior of fibroblasts and immune cells leading to metastasis formation and chemotherapy resistance, which contribute to the high lethality of PDAC. Additionally, recent evidence highlights that ECM, as a major structural component of the tumor microenvironment, is a highly dynamic structure in which ECM proteins establish a physical and biochemical niche for cancer stem cells (CSCs). CSCs are characterized by self-renewal, tumor initiation, and resistance to chemotherapeutics. In this review, we will discuss the effects of the ECM on tumor biological behavior and its molecular impact on the fundamental signaling pathways in PDAC. We will also provide an overview of how the different ECM components are able to modulate CSCs properties and finally discuss the current and ongoing therapeutic strategies targeting the ECM. Given the many challenges facing current targeted therapies for PDAC, a better understanding of molecular events involving the interplay of ECM and CSC will be key in identifying more effective therapeutic strategies to eliminate CSCs and ultimately to improve survival in patients that are suffering from this deadly disease.

MicroRNA-497 prevents pancreatic cancer stem cell gemcitabine resistance, migration, and invasion by directly targeting nuclear factor kappa B 1.

Objectives: Cancer stem cells (CSCs) comprise a small population of cells in cancerous tumors and play a critical role in tumor resistance to chemotherapy. miRNAs have been reported to enhance the sensitivity of pancreatic cancer to chemotherapy. However, the underlying molecular mechanism requires better understanding.Methods: Cell viability and proliferation were examined with CCK8 assays. Quantitative real-time polymerase chain reaction was executed to assess mRNA expression. StarBase database was used to select the target genes of miRNA, which were further affirmed by dual luciferase assay. Transwell assay was used to analyze cell invasion and migration.Results: We proved that miR-497 could be obviously downregulated in pancreatic cancer tissues and CSCs from Aspc-1 and Bxpc-3 cells. In addition, inhibition of miR-497 evidently accelerated pancreatic CSC gemcitabine resistance, migration and invasion. Moreover, we revealed that nuclear factor kappa B 1 (NFκB1) was prominently upregulated in pancreatic cancer tissues and pancreatic CSCs, and NFκB1 was also identified as a direct target of miR-497. Furthermore, we demonstrated that overexpression of NFκB1 could also notably promote the viability, migration, and invasion of gemcitabine-treated pancreatic CSCs, but this effect could be partially abolished by miR-497 overexpression.Conclusions: Those findings suggest that miR-497 overexpression could suppress gemcitabine resistance and the metastasis of pancreatic CSCs and non-CSCs by directly targeting NFκB1.

Activation of MYO1G by lncRNA MNX1-AS1 Drives the Progression in Lung Cancer.

Lung cancer represents the most prevalent cancer worldwide and causes the death of many patients. Cancer stem cells (CSCs), a subpopulation of cancer cells, have the capacities of self-renewal, unlimited proliferation, and multiple differentiation potential. The purpose of this study was to explore the potential role of long noncoding RNA (lncRNA) MNX1-AS1 on maintaining the stemness of CSC in lung cancer. CSCs were firstly sorted by flow cytometry. After the determination of the target of the present study using Gene Expression Omnibus dataset, MNX1-AS1was found to be highly expressed in lung cancer tissues and cells. Deletion of MNX1-AS1 inhibited proliferation, migration, invasion and sphere-forming abilities of CSC. Furthermore, subcellular fractionation, fluorescence in situ hybridization, RNA immunoprecipitation, and dual-luciferase experiments demonstrated that MNX1-AS1 recruited the transcription factor POU domain class 2 transcription factor 2 (POU2F2) to the nucleus and activated the myosin IG (MYO1G) expression. MYO1G overexpression partially reversed the si-MNX1-AS1-decreased stemness of CSCs. Finally, MNX1-AS1 suppression significantly repressed the growth of xenografts in vivo. Our study highlights the importance of the MNX1-AS1/POU2F2/MYO1G axis in stem cell-like properties of lung cancer cells.

LncRNA LINC01315 silencing modulates cancer stem cell properties and epithelial-to-mesenchymal transition in colorectal cancer via miR-484/DLK1 axis

ABSTRACT Long non-coding RNA long intergenic non-protein coding RNA 01315 (LncRNA LINC01315) has been found to be implicated in various cancers, but its role and functions in colorectal cancer (CRC) remain to be addressed. Data on LINC01315 expression in CRC were gathered using bioinformatics analysis, and cancer stem cells (CSCs) were sorted by aldehyde dehydrogenase (ALDH) assay and flow cytometry. Migration, invasion, and stemness of CSCs isolated from CRC cells after transfection were determined by scratch, Transwell, and sphere-formation assays, respectively. Tumor xenograft model was constructed. Target genes and potential-binding sites were predicted using online databases and further confirmed via dual-luciferase reporter assay. Relative factors expressions were determined via quantitative real-time polymerase-chain reaction and Western blot as needed. LINC01315 was high-expressed in CRC and ALDH+ cells. LINC01315 silencing suppressed the migration, invasion, and sphere formation of CRC cells and tumor growth, and downregulated expressions of CSC molecules (ALDH, cluster of difference 44 (CD44), Prominin, and sex determining region Y-box 2 (SOX2)), Zinc Finger E-Box Binding Homeobox 1 (ZEB1) and Vimentin but upregulated E-Cadherin expression. MiR-484 could competitively bind with LINC01315, and LINC01315 silencing promoted miR-484 expression. The level of Delta Like Non-Canonical Notch Ligand 1 (DLK1), the target gene of miR-484, was enhanced by overexpressed LINC01315 yet was suppressed by LINC01315 silencing. Also, DLK1 silencing reversed the effects of downregulated miR-484 on migration, invasion, sphere formation, and CSC molecules expressions in CRC cells. LINC01315 silencing modulated CSC properties and epithelial-to-mesenchymal transition via miR-484/DLK1 axis.

Evaluation of hydroalcoholic extract effects of Ferula assa-foetida on expression change of EMT and CD44-related genes in gastric cancer stem cell

BackgroundGastric cancer (GC) with high incidence is a life-threatening malignant tumor in humans. Cancer stem cells (CSCs) due to tumor-initiating capacity, ability of invasion, metastasis, recurrence, and chemoresistance may be utilized for cancer treatment. Ferula assa-foetida as a herbal remedy in ancient Iranian medicine was shown to have various biological activities, including anti-cancer. Epithelial-mesenchymal transition (EMT) markers play an important role in migration, invasion, and metastatic dissemination of CSCs. The gastric CSCs-surface glycoprotein CD44 also responsible for high tumorigenicity, self-renewal, and metastasis through EMT. In this study, we investigated the hydroalcoholic extract effects of F. assa-foetida on the expression of EMT-related genes, anti-apoptotic factor Bcl-2 and CD44 cell-surface molecule in CSCs. MethodsCSCs were cultured in serum-free medium containing EGF and B-27 and exposed to different concentrations of F. assa-foetida hydroalcoholic extract and for different time durations. Cytotoxic effects of the extract compounds were evaluated using MTT assay. After CSCs treatment with IC50 dose of the extract, the expression level of EMT markers vimentin, Snail1, and Zeb1 and anti-apoptotic marker Bcl-2 was determined using relative quantitative real-time PCR as well as marker CD44 and CD54 were determined by flow cytometry. ResultsOur MTT assay results demonstrated that cytotoxicity effect of extract compounds was significantly dependent on time and concentration. After exposing CSCs to IC50 doses of extract in different times, mRNA expression levels of EMT markers (vimentin, Snail1, Zeb1) and anti-apoptotic marker Bcl-2, as well as protein expression of stemness marker CD44 and CD54 significantly decreased in treated CSCs compared with untreated (P < 0.05). ConclusionOur data demonstrated that extract compounds of F. assa-foetida were able to decrease EMT markers, Bcl-2 anti-apoptotic factor, surface marker of CD44 and CD54, leading to inhibition of CSCs proliferation as well as killing of them. Therefore, isolation and purification of F. assa-foetida hydroalcoholic extract could be used as a potential agent for cancer treatment.

Caveolin1: its roles in normal and cancer stem cells.

Stem cells are characterized by the capability of self-renewal and multi-differentiation. Normal stem cells, which are important for tissue repair and tissue regeneration, can be divided into embryonic stem cells (ESCs) and somatic stem cells (SSCs) depending on their origin. As a subpopulation of cells within cancer, cancer stem cells (CSCs) are at the root of therapeutic resistance. Tumor-initiating cells (TICs) are necessary for tumor initiation. Caveolin1 (Cav1), a membrane protein located at the caveolae, participates in cell lipid transport, cell migration, cell proliferation, and cell signal transduction. The purpose of this review was to explore the relationship between Cav1 and stem cells. In ESCs, Cav1 is beneficial for self-renewal, proliferation, and migration. In SSCs, Cav1 exhibits positive or/and negative effects on stem cell self-renewal, differentiation, proliferation, migration, and angiogenic capacity. Cav1 deficiency impairs normal stem cell-based tissue repair. In CSCs, Cav1 inhibits or/and promotes CSC self-renewal, differentiation, invasion, migration, tumorigenicity ability, and CSC formation. And suppressing Cav1 promotes chemo-sensitivity in CSCs and TICs. Cav1 shows dual roles in stem cell biology. Targeting the Cav1-stem cell axis would be a new way for tissue repair and cancer drug resistance.

Proteases Regulate Cancer Stem Cell Properties and Remodel Their Microenvironment.

Proteolytic activity is perturbed in tumors and their microenvironment, and proteases also affect cancer stem cells (CSCs). CSCs are the therapy-resistant subpopulation of cancer cells with tumor-initiating capacity that reside in specialized tumor microenvironment niches. In this review, we briefly summarize the significance of proteases in regulating CSC activities with a focus on brain tumor glioblastoma. A plethora of proteases and their inhibitors participate in CSC invasiveness and affect intercellular interactions, enhancing CSC immune, irradiation, and chemotherapy resilience. Apart from their role in degrading the extracellular matrix enabling CSC migration in and out of their niches, we review the ability of proteases to modulate CSC properties, which prevents their elimination. When designing protease-oriented therapies, the multifaceted roles of proteases should be thoroughly investigated.

Repeated Irradiation with γ-Ray Induces Cancer Stemness through TGF-β-DLX2 Signaling in the A549 Human Lung Cancer Cell Line.

Cancer stem cells (CSCs) play an important role in cancer recurrence and metastasis. It is suggested that the CSC properties in heterogeneous cancer cells can be induced by ionizing radiation (IR). This study investigated the role of DLX2 in the radioresistance and CSC properties induced by IR in NSCLC cancer cells. Here, A549 cells were exposed to fractionated irradiation at a cumulative dose of 52 Gy (4 Gy × 13 times) for a generation of radioresistant cells. After fractionated irradiation, surviving A549 cells exhibited resistance to IR and enhanced expression of various cancer stem cell markers. They also showed upregulation of mesenchymal molecular markers and downregulation of epithelial molecular markers, correlating with an increase in the migration and invasion. Fractionated irradiation triggered the secretion of TGF-β1 and DLX2 expression. Interestingly, the increased DLX2 following fractionated irradiation seemed to induce the expression of the gene for the EGFR-ligand betacellulin via Smad2/3 signaling. To contrast, DLX2 knockdown dramatically decreased the expression of CSC markers, migration, and proliferation. Moreover, A549 cells expressing DLX2 shRNA formed tumors with a significantly smaller volume compared to those expressing control shDNA in a mouse xenograft assay. These results suggest that DLX2 overexpression in surviving NSCLC cancer cells after fractionated IR exposure is involved in the cancer stemness, radioresistance, EMT, tumor survival, and tumorigenic capability.

13R,20-Dihydroxydocosahexaenoic Acid, a Novel Dihydroxy- DHA Derivative, Inhibits Breast Cancer Stemness through Regulation of the Stat3/IL-6 Signaling Pathway by Inducing ROS Production.

Breast cancer is a major health problem worldwide. Cancer stem cells (CSCs) are known to mediate breast cancer metastasis and recurrence and are therefore a promising therapeutic target. In this study, we investigated the anti-inflammatory effect of 13R,20-dihydroxydocosahexaenoic acid (13R,20-diHDHA), a novel dihydroxy-DHA derivative, which was synthesized through an enzymatic reaction using cyanobacterial lipoxygenase. We found that 13R,20-diHDHA reduced the macrophage secretion of the inflammatory cytokines, IL-6 and TNF-α, and thus appeared to have anti-inflammatory effects. As the inflammatory tumor microenvironment is largely devoted to supporting the cancer stemness of breast cancer cells, we investigated the effect of 13R,20-diHDHA on breast cancer stemness. Indeed, 13R,20-diHDHA effectively inhibited breast cancer stemness, as evidenced by its ability to dose-dependently inhibit the mammospheres formation, colony formation, migration, and invasion of breast CSCs. 13R,20-diHDHA reduced the populations of CD44high/CD24low and aldehyde dehydrogenase (ALDH)-positive cells and the expression levels of the cancer stemness-related self-renewal genes, Nanog, Sox2, Oct4, c-Myc, and CD44. 13R,20-diHDHA increased reactive oxygen species (ROS) production, and the generated ROS reduced the phosphorylation of nuclear signal transducer and activator of transcription 3 (Stat3) and the secretion of IL-6 by mammospheres. These data collectively suggest that 13R,20-diHDHA inhibits breast cancer stemness through ROS production and downstream regulation of Stat3/IL-6 signaling, and thus might be developed as an anti-cancer agent acting against CSCs.

Modulation of LXR signaling altered the dynamic activity of human colon adenocarcinoma cancer stem cells in vitro

BackgroundThe expansion and metastasis of colorectal cancers are closely associated with the dynamic growth of cancer stem cells (CSCs). This study aimed to explore the possible effect of LXR (a regulator of glycolysis and lipid hemostasis) in the tumorgenicity of human colorectal CD133 cells.MethodsHuman HT-29 CD133+ cells were enriched by MACS and incubated with LXR agonist (T0901317) and antagonist (SR9243) for 72 h. Cell survival was evaluated using MTT assay and flow cytometric analysis of Annexin-V. The proliferation rate was measured by monitoring Ki-67 positive cells using IF imaging. The modulation of LXR was studied by monitoring the activity of all factors related to ABC transporters using real-time PCR assay and western blotting. Protein levels of metabolic enzymes such as PFKFB3, GSK3β, FASN, and SCD were also investigated upon treatment of CSCs with LXR modulators. The migration of CSCs was monitored after being exposed to LXR agonist using scratch and Transwell insert assays. The efflux capacity was measured using hypo-osmotic conditions. The intracellular content of reactive oxygen species was studied by DCFH-DA staining.ResultsData showed incubation of CSCs with T0901317 and SR9243 reduced the viability of CD133 cells in a dose-dependent manner compared to the control group. The activation of LXR up-regulated the expression and protein levels of ABC transporters (ABCA1, ABCG5, and ABCG8) compared to the non-treated cells (p < 0.05). Despite these effects, LXR activation suppressed the proliferation, clonogenicity, and migration of CD133 cells, and increased hypo-osmotic fragility (p < 0.05). We also showed that SR9243 inhibited the proliferation and clonogenicity of CD133 cells through down-regulating metabolic enzymes PFKFB3, GSK3β, FASN, and SCD as compared with the control cells (p < 0.05). Intracellular ROS levels were increased after the inhibition of LXR by SR9243 (p < 0.05).Calling attention, both T0901317 and SR9243 compounds induced apoptotic changes in cancer stem cells (p < 0.05).ConclusionsThe regulation of LXR activity can be considered as a selective targeting of survival, metabolism, and migration in CSCs to control the tumorigenesis and metastasis in patients with advanced colorectal cancers.