scholarly journals Leukemic stem cells: from metabolic pathways and signaling to a new concept of drug resistance targeting.

2007 ◽  
Vol 54 (4) ◽  
pp. 717-726 ◽  
Author(s):  
Jan Styczynski ◽  
Tomasz Drewa

Cancer stem cells are a small subset of cancer cells constituting a reservoir of self-sustaining cells with the exclusive ability to self-renew and maintain the tumor. These cells are identified by specific stem cell markers: antigens, molecules and signaling pathways. Transcription factors and molecules associated with oncogenesis, such as NF-kappaB, Bmi-1, Notch, WNT beta-catenin, Sonic hedgehog and their biochemical pathways, active only in a small minority of cancer cells might play key roles in determining the biology and the overall long-term behavior of a tumor. The molecules and pathways specific for cancer stem cells, which contribute to their drug resistance, are potential targets for new therapeutic strategies.

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Lijuan Zou ◽  
Hengpeng He ◽  
Zhiguo Li ◽  
Ou Chen ◽  
Xiukun Jia ◽  
...  

AbstractLong noncoding RNAs (lncRNAs) are implicated tumor development in a range of different cancers, including pancreatic cancer (PC). Cancer stem cells (CSCs), a drug-resistant cancer cell subset, drive tumor progression in PC. In this work, we aimed to investigate the mechanism by which lncRNA LINC00261 affects the biological functions of CSCs during the progression of PC. Microarray analysis of differentially expressed genes and lncRNAs suggested that LINC00261 is downregulated in PC. Both LINC00261 and ITIH5 were confirmed to be downregulated in PC cells and PC stem cells. Gain-of-function and loss-of-function investigations were performed to analyze their effects on cell proliferation, drug resistance, cell cycle distribution, self-renewal, invasion, and ultimately overall tumorigenicity. These experiments revealed that the expression of stem cell markers was reduced, and cell proliferation, self-renewal ability, cell invasion, drug resistance, and tumorigenicity were all suppressed by upregulation of LINC00261 or ITIH5. The results of dual-luciferase reporter gene, ChIP, and RIP assays indicated that LINC00261 binds directly to GATA6, increasing its activity at the ITIH5 promoter. The presence of LINC00261 and GATA6 inhibited the self-renewal and tumorigenesis of PC stem cells, while silence of ITIH5 rescued those functions. Collectively, this study identifies the tumor suppressive activity of LINC00261 in PC, showing that this lncRNA limits the functions of PC stem through an ITIH5/GATA6 regulatory pathway.


Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1450 ◽  
Author(s):  
Patrick Santos ◽  
Fausto Almeida

Tumor microenvironment (TME) is composed of different cellular populations, such as stromal, immune, endothelial, and cancer stem cells. TME represents a key factor for tumor heterogeneity maintenance, tumor progression, and drug resistance. The transport of molecules via extracellular vesicles emerged as a key messenger in intercellular communication in the TME. Exosomes are small double-layered lipid extracellular vesicles that can carry a variety of molecules, including proteins, lipids, and nucleic acids. Exosomal miRNA released by cancer cells can mediate phenotypical changes in the cells of TME to promote tumor growth and therapy resistance, for example, fibroblast- and macrophages-induced differentiation. Cancer stem cells can transfer and enhance drug resistance in neighboring sensitive cancer cells by releasing exosomal miRNAs that target antiapoptotic and immune-suppressive pathways. Exosomes induce drug resistance by carrying ABC transporters, which export chemotherapeutic agents out of the recipient cells, thereby reducing the drug concentration to suboptimal levels. Exosome biogenesis inhibitors represent a promising adjunct therapeutic approach in cancer therapy to avoid the acquisition of a resistant phenotype. In conclusion, exosomal miRNAs play a crucial role in the TME to confer drug resistance and survivability to tumor cells, and we also highlight the need for further investigations in this promising field.


2014 ◽  
Vol 13 (6) ◽  
pp. 529-540 ◽  
Author(s):  
Mina Kim ◽  
Yoo-Sun Kim ◽  
Kyung-Mi Kim ◽  
Hee-Chul Ko ◽  
Se-Jae Kim ◽  
...  

Lung cancer is the leading cause of cancer death worldwide, and most chemotherapeutic drugs have limited success in treating this disease. Furthermore, some drugs show undesirable side effects due to the enrichment of cancer stem cells (CSCs) that are present, leading to resistance to conventional chemotherapy and tumor relapse. CSCs possess self-renewal characteristics, aggressive tumor initiating activity, and ability to facilitate tumor metastasis. Therefore, development of nontoxic agents that can potentiate chemotherapy and eliminate CSCs would be highly desirable. In the present study, we investigated whether Sasa quelpaertensis leaf extracts (SQE) and cisplatin (CIS), individually or in combination, would exert anti-CSC and antimetastatic effect in H1299 and A549 human lung cancer cells. Following these treatments, cell growth, phosphorylation of phosphoinositide-3 kinase, and activation of the mammalian target of rapamycin were inhibited. Decreased serial sphere formation, clonogenicity, and expression of major stem cell markers, such as CD44 and SOX-2, in CD44+ cancer stem cells were also observed. In addition, inhibition of cell migration and invasion in both cell lines as well as inhibition of matrix metalloproteinase-2 activity and expression were detected. Importantly, the anticancer stemness and antimetastasis effects in each of these assays were greater for the combined treatment with SQE and CIS than with each treatment individually. In conclusion, the data suggest that SQE alone, or in combination with CIS, represents a promising therapeutic strategy for eliminating cancer stemness and cell invasion potential of CSCs, thereby treating and preventing metastatic lung cancer cells.


2019 ◽  
Vol 43 (1) ◽  
pp. 123-136 ◽  
Author(s):  
Zhiyong Yang ◽  
Ning Zhao ◽  
Jing Cui ◽  
Heshui Wu ◽  
Jiongxin Xiong ◽  
...  

Abstract Purpose Gemcitabine (GEM)-based chemotherapy is the first-line treatment for locally advanced pancreatic cancer. GEM resistance, however, remains a significant clinical challenge. Here, we investigated whether exosomes derived from GEM-resistant pancreatic cancer stem cells (CSCs) mediate cell-cell communication between cells that are sensitive or resistant to GEM and, by doing so, regulate drug resistance. Methods GEM-sensitive BxPC-3-derived BxS and PANC-1 pancreatic cancer cells were cultured with exosomes extracted from CSCs isolated from GEM-resistant BxPC-3-derived BxR cells (BxR-CSC). The effect of exosomes on drug resistance, cell cycle progression, apoptosis and miRNA expression was evaluated in BxS and PANC-1 cells. Relevant miRNAs associated with GEM resistance were identified and the role of miR-210 in conferring drug resistance was examined in vitro and in vivo. Results BxR-CSC-derived exosomes induced GEM resistance, inhibited GEM-induced cell cycle arrest, antagonized GEM-induced apoptosis, and promoted tube formation and cell migration in BxS and PANC-1 cells. Elevated miR-210 expression levels were detected in BxR-CSCs and BxR-CSC-derived exosomes compared to those in BxS-CSCs and BxS-CSC-derived exosomes. In addition, increased expression levels of miR-210 were observed in BxS and PANC-1 cells cultured with BxR-CSC-derived exosomes upon exposure to GEM in a dose-dependent manner. Also, a series of biological changes was observed in BxS cells after transfection with miR-210 mimics, including activation of the mammalian target of rapamycin (mTOR) signaling pathway, and these changes were similar to those triggered by BxR-CSC-derived exosomes. Conclusions Our findings suggest that exosomes derived from GEM-resistant pancreatic cancer stem cells mediate the horizontal transfer of drug-resistant traits to GEM-sensitive pancreatic cancer cells by delivering miR-210.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ryan Green ◽  
Mark Howell ◽  
Roukiah Khalil ◽  
Rajesh Nair ◽  
Jiyu Yan ◽  
...  

AbstractThe failure of lung cancer treatments has been attributed mostly to the development of drug resistance, however the underlying cellular and molecular mechanisms are poorly understood. Cancer initiating stem cells (CSCs), present in tumors in a small percentage, play critical roles in the development of drug resistance, metastasis, and cancer relapse. Hence, novel treatments targeting both bulk cancer cells and CSCs are under intense investigation. Herein, we report that lung cancer cells grown on a 3D fibrous scaffold form tumoroids that resemble in vivo tumors, expand CSCs, and provide a platform to identify anti-CSC drugs. The screening of an NCI library of FDA-approved drugs using tumoroid cultures led to identification of Actinomycin D (AD) as a top CSC inhibitor. Since CSCs are mostly resident in the tumor’s inner core, AD was combined with an angiotensin receptor antagonist, Telmisartan (TS), which is known to increase drug permeability in tumors and was shown to have anti-CSC activity. Our results showed that AD + TS administered intra-tumorally was significantly more effective than either drug alone in both syngeneic and xenograft mouse models. The results of mechanistic studies revealed that CSC expansion in tumoroids was associated with activation of β catenin signaling and that AD + TS treatment reduced active β catenin levels in tumors. Together, these results establish the utility of the tumoroid culture system to expand CSCs ex vivo for targeted drug screening, to identify promising novel treatments with both anti-CSC and anti-cancer effects, and to individualize treatments for metastatic drug resistant lung cancer patients.


2020 ◽  
Author(s):  
Ved P Sharma ◽  
Binwu Tang ◽  
Yarong Wang ◽  
George S Karagiannis ◽  
Emily A Xue ◽  
...  

ABSTRACTCancer stem cells (CSCs) play an important role during metastasis, but the dynamic behavior and induction mechanisms of CSCs are not well understood. We employed high-resolution intravital microscopy using a CSC biosensor to directly observe CSCs in live mice with mammary tumors. CSCs display the slow-migratory, invadopod-rich phenotype that is the hallmark of disseminating tumor cells. CSCs are enriched near macrophages, particularly near macrophage-containing intravasation sites called Tumor Microenvironment of Metastasis (TMEM) doorways. A dramatic enrichment of CSCs occurs on association with TMEM doorways, contributing to the finding that CSCs represent ∼>60% of circulating tumor cells. Mechanistically, stemness is induced in non-stem cancer cells upon their direct contact with macrophages via Notch signaling. In breast cancers from patients, the density of TMEM doorways correlates strongly with the proportion of cancer cells expressing stem cell markers, indicating that in human breast cancer TMEM doorways are not only cancer cell intravasation portals but also CSC programming sites.One Sentence SummaryIntravital imaging reveals macrophage-mediated induction of cancer stem cells in vivo and their dramatic enrichment on dissemination through TMEM doorways.


MedChemComm ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Calabrese Gianpiero ◽  
Daou Anis ◽  
Rova Aikaterini ◽  
Tseligka Eirini ◽  
Vizirianakis S. Ioannis ◽  
...  

To limit the incidence of relapse, cancer treatments must not promote the emergence of drug resistance in tumour and cancer stem cells.


2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e15058-e15058
Author(s):  
Kalliopi Andrikou ◽  
Luca Faloppi ◽  
Cristian Loretelli ◽  
Alessandra Mandolesi ◽  
Italo Bearzi ◽  
...  

e15058 Background: Emerging evidence has suggested that malignant tumors are heterogeneous and that are composed of a small subset of distinct cancer cells (usually defined by cell surface marker expression) that are responsible for tumor initiation and propagation, termed cancer stem cells. These cancer stem cells (CSCs), or tumor-initiating cells (TICs), exhibit properties of normal stem cells and are associated with resistance to current therapies. It was found that human pancreatic cancer has shown a population of cancer stem cells that have aberrantly activated developmental signaling pathways, are resistant to standard chemotherapy and radiation, and have up-regulated signaling cascades that are integral for tumor metastasis. The aim of our study is to investigate the prognostic implication of cancer stem cell markers in pancreatic ductal adenocarcinoma. Methods: In 43 histological samples of pancreatic ductal adenocarcinoma were performed molecular biology assessment of CD 24, CD44, CD133, CD166, OCT3/4, LGR5. Results: At univariate analysis patients with an overexpression of CD44, CD133, OCT3/4 showed a worse prognosis in terms of overall survival (respectively: p=0.031; p=0.014; p=0.001). At multivariate analysis OCT3/4 resulted to be independent factor influencing outcome (HR=0.23). Patients with overexpression of all factors seem to have a worse OS compared to patients expressing only two, one or none (8.6 vs. 15.6 vs. 18.0 vs. 59.9 mts; p=0.006). Conclusions: Our data suggest that the presence of cancer stem cells could be linked with tumor aggressiveness and patients’ survival. This finding could drive therapeutic decision towards less or more intensive treatment.


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