Cancer Stem Cells In Progression Research Articles

Exploring the Pivotal Association of AI in Cancer Stem Cells Detection and Treatment

Cancer stem cells (CSCs), or tumor-initiating cells (TICs), are cancerous cell subpopulations that remain while tumor cells propagate as a unique subset and exhibit multiple applications in several diseases. They are responsible for cancer cell initiation, development, metastasis, proliferation, and recurrence due to their self-renewal and differentiation abilities in many kinds of cells. Artificial intelligence (AI) has gained significant attention because of its vast applications in various fields including agriculture, healthcare, transportation, and robotics, particularly in detecting human diseases such as cancer. The division and metastasis of cancerous cells are not easy to identify at early stages due to their uncontrolled situations. It has provided some real-time pictures of cancer progression and relapse. The purpose of this review paper is to explore new investigations into the role of AI in cancer stem cell progression and metastasis and in regenerative medicines. It describes the association of machine learning and AI with CSCs along with its numerous applications from cancer diagnosis to therapy. This review has also provided key challenges and future directions of AI in cancer stem cell research diagnosis and therapeutic approach.

The role of ncRNAs and exosomes in the development and progression of endometrial cancer.

Endometrial cancer (EC) is one of the most common gynecologic cancers. In recent years, research has focused on the genetic characteristics of the tumors to detail their prognosis and tailor therapy. In the case of EC, genetic mutations have been shown to underlie their formation. It is very important to know the mechanisms of EC formation related to mutations induced by estrogen, among other things. Noncoding RNAs (ncRNAs), composed of nucleotide transcripts with very low protein-coding capacity, are proving to be important. Their expression patterns in many malignancies can inhibit tumor formation and progression. They also regulate protein coding at the epigenetic, transcriptional, and posttranscriptional levels. MicroRNAs (miRNAs), several varieties of which are associated with normal endometrium as well as its tumor, also play a particularly important role in gene expression. MiRNAs and long noncoding RNAs (lncRNAs) affect many pathways in EC tissues and play important roles in cancer development, invasion, and metastasis, as well as resistance to anticancer drugs through mechanisms such as suppression of apoptosis and progression of cancer stem cells. It is also worth noting that miRNAs are highly precise, sensitive, and robust, making them potential markers for diagnosing gynecologic cancers and their progression. Unfortunately, as the incidence of EC increases, treatment becomes challenging and is limited to invasive tools. The prospect of using microRNAs as potential candidates for diagnostic and therapeutic use in EC seems promising. Exosomes are extracellular vesicles that are released from many types of cells, including cancer cells. They contain proteins, DNA, and various types of RNA, such as miRNAs. The noncoding RNA components of exosomes vary widely, depending on the physiology of the tumor tissue and the cells from which they originate. Exosomes contain both DNA and RNA and have communication functions between cells. Exosomal miRNAs mediate communication between EC cells, tumor-associated fibroblasts (CAFs), and tumor-associated macrophages (TAMs) and play a key role in tumor cell proliferation and tumor microenvironment formation. Oncogenes carried by tumor exosomes induce malignant transformation of target cells. During the synthesis of exosomes, various factors, such as genetic and proteomic data are upregulated. Thus, they are considered an interesting therapeutic target for the diagnosis and prognosis of endometrial cancer by analyzing biomarkers contained in exosomes. Expression of miRNAs, particularly miR-15a-5p, was elevated in exosomes derived from the plasma of EC patients. This may suggest the important utility of this biomarker in the diagnosis of EC. In recent years, researchers have become interested in the topic of prognostic markers for EC, as there are still too few identified markers to support the limited treatment of endometrial cancer. Further research into the effects of ncRNAs and exosomes on EC may allow for cancer treatment breakthroughs.

Hypoxia-induced cancer cell reprogramming: a review on how cancer stem cells arise.

Cancer stem cells are a subset of cells within the tumor that possess the ability to self-renew as well as differentiate into different cancer cell lineages. The exact mechanisms by which cancer stem cells arise is still not completely understood. However, current research suggests that cancer stem cells may originate from normal stem cells that have undergone genetic mutations or epigenetic changes. A more recent discovery is the dedifferentiation of cancer cells to stem-like cells. These stem-like cells have been found to express and even upregulate induced pluripotent stem cell markers known as Yamanaka factors. Here we discuss developments in how cancer stem cells arise and consider how environmental factors, such as hypoxia, plays a key role in promoting the progression of cancer stem cells and metastasis. Understanding the mechanisms that give rise to these cells could have important implications for the development of new strategies in cancer treatments and therapies.

Quinacrine inhibits cMET-mediated metastasis and angiogenesis in breast cancer stem cells.

A trans-membrane receptor tyrosine kinase, cMET, belonging to the MET proto-oncogene family, is responsible for cancer metastasis and angiogenesis. But not much is known about the role of cMET in growth and progression of cancer stem cells (CSCs). Earlier studies have shown that Quinacrine (QC), a bioactive agent, has anti-CSCs activity. Here, the role of QC in deregulation of cMET-mediated metastasis and angiogenesis has been systematically evaluated in vitro in highly metastatic breast CSCs (mBCSCs), ex vivo in patient-derived breast cancer stem cells (PDBCSCs) and in vivo in xenograft mice model systems. Cell proliferation, migration, invasion and representative metastasis markers were upregulated in cMET-overexpressed cells and QC exposure inhibited these processes in both mBCSCs and PDBCSCs. Interestingly, metastasis was significantly inhibited by QC in cMET-overexpressed cells but comparatively lesser significant alteration of the process was noted in cMET-silenced cells. Increase in vascularization (in in ovo CAM assay), and cell-cell tube formation (in HUVECs), and enhanced MMP9 and MMP2 enzymatic activities (in gelatin zymography) were noted after cMET overexpression but these processes got reversed after cMET knockdown or QC treatment in cMET-overexpressed cells. QC inhibited angiogenesis significantly in cMET-overexpressed cells, but lesser significant change was observed in cMET-silenced cells. Reduction in tumor volume and decreased expression of metastatic and angiogenic markers were also noted in xenograft mice after QC treatment. Furthermore, QC inhibited cMET activity by dephosphorylation of its tyrosine residues (Y1234 and Y1356) and downregulation of its downstream cascade. Thus, QC inhibited the cMET-mediated metastasis and angiogenesis in in vitro, in ovo, in vivo and ex vivo model systems. Ligand (HGF) binding leads to receptor dimerization and phosphorylation of tyrosine kinase domain of cMET. This activates the cMET signaling cascade. The representative downstream metastasis and angiogenesis-related proteins get upregulated and induce the metastasis and angiogenesis process. But after the QC treatment, cMET get dephosphorylated and inactivated. As a result, the downstream signaling proteins of cMET along with the other representative metastatic and angiogenic factors get downregulated. These lead to inhibition of cMET-mediated metastasis and angiogenesis. (Created with BioRender.com).

EHD1 promotes the cancer stem cell (CSC)-like traits of glioma cells via interacting with CD44 and suppressing CD44 degradation.

Plenty of evidence has shown that endocytosis plays a key role in cancer progression; however, its effects in the progression of cancer stem cells (CSCs) are still fragmentary. In the present study, we firstly identified that mammalian Eps15 homology domain protein 1 (EHD1), an endocytic and metastasis-associated gene, was upregulated in the 3D non-adherent spheres derived from glioma cells compared to that in the corresponding parental cells. Further functional experiments revealed that EHD1 knockdown reduced the CSC-like traits of glioma cells, which were evident by the decrease of sphere-formation ability, ALDH1 activity, and CSC markers' expression. Additionally, EHD1 knockdown attenuated the tumor-initiating ability of glioma cells in vivo. Furthermore, it was shown that EHD1 bound to CD44, enhanced CD44 stability, and prevented its total ubiquitination. Indeed, overexpression of CD44 rescued the inhibitory effects of EHD1 knockdown on the CSC-like traits of glioma cells. Finally, through the online dataset analysis, we found that EHD1 indeed exhibited a higher level in glioma tissues relative to that in normal tissues, and a positive correlation with CSC markers' expression in glioma tissues. Notably, EHD1 expression was negatively correlated with the overall survival and relapse-free survival of glioma patients. Thus, this work indicates that EHD1 might be a potent target for glioma progression, especially through breaking the EHD1-CD44 interaction.

ANGPTL1 attenuates cancer migration, invasion, and stemness through regulating FOXO3a-mediated SOX2 expression in colorectal cancer.

Angiopoietin-like protein 1 (ANGPTL1) is a member of the ANGPTL family that suppresses angiogenesis, cancer invasion, metastasis, and cancer progression. ANGPTL1 is down-regulated in various cancers including colorectal cancer (CRC); however, the effects and mechanisms of ANGPTL1 on liver metastasis and cancer stemness in CRC are poorly understood. In the present study, we identified that ANGPTL1 was down-regulated in CRC and inversely correlated with metastasis and poor clinical outcomes in CRC patients form the ONCOMINE database and Human Tissue Microarray staining. ANGPTL1 significantly suppressed the migration/invasion abilities, the expression of cancer stem cell (CSC) markers, and sphere formation by enhancing FOXO3a expression, which contributed to the reduction of stem cell transcription factor SOX2 expression in CRC cells. Consistently, overexpression of ANGPTL1 reduced liver metastasis, tumor growth, and tumorigenicity in tumor-bearing mice. ANGPTL1 expression was negatively correlated with CSC markers expression and poor clinical outcomes in CRC patients. Taken together, these findings demonstrate that the molecular mechanisms of ANGPTL1 in colorectal cancer stem cell progression may provide a novel therapeutic strategy for CRC.

Prognosis role of epitelial-mezenchimal transformation markers and surface stem tumor cells in the reccurence of serous low grade ovarian carcinomas

Ovarian cancer remains one of the most fatal pathologies among women around the world due to late diagnosis on the advanced stages of the tumor process. Serous ovarian carcinomas (SOC) often recur, which worsens the prognosis for patients’ recovery and survival. The identification of prognostic clinical and morphological factors that predict the appearance of recurrence remains an urgent problem.
 The aim of the research was studying relationships between the phenomenon of epithelial-mesenchymal transformation (EMT) and the expression of surface cancer stem cells (CSCS) markers to identify recurrence predictors among women with low grade serous ovarian carcinomas (LGSC).
 The material were paraffin blocks and slides of 43 patients with LGSC I-IV FIGO stage. The study included 30 cancers without recurrence and 13 tumors with it within 24 months. The expression of E-cadherin, Vimentin, CD44 and CD117 was studied using immunohistochemical (IHC) method.
 Results. Development of recurrence is typical for women with stage III-IV (p=0,01), the expression of Vimentin at level 51–100 % (p=0,001) and E-cadherin at 10–50 % (p=0.04). CD44 was expressed in 51.16 % of tumors and level didn`t depend on age, recurrence, but depended on disease stage (p=0.001). Recurrent LGSCs are characterized by the expression of CD117> 10 % (p=0.0001), its direct correlation with the stage (p=0.0001) and the recurrence (p=0.0001). A direct relationship was found between the CD117 and Vimentin expression.
 Conclusions. Prognostic markers of recurrence should be considered stage III-IV, levels of Vimentin 51–100 %, E-cadherin 10-50 % and CD117> 10 %. A correlation between CD117 and Vimentin expression indicates the commonality of EMT and CSCS in progression and recur. CD44 has no independent prognostic role.

Human Papilloma Virus and Cancer Stem Cell markers in Oral Epithelial Dysplasia-An Immunohistochemical Study.

ObjectivesTo study the correlation between the putative cancer stem cell (CSC) markers aldehyde dehydrogenase 1 (ALDH1), cluster of differentiation 44 (CD44), sex-determining region Y-box 2 (SOX2), and octamer-binding protein 4 (OCT4) and human papilloma virus (HPV) infection using p16, the surrogate marker of HPV in oral epithelial dysplasia (OED) and normal mucosa.MethodsFive sections each from 40 histopathologically diagnosed cases of different grades of OED and 10 cases of normal oral mucosa without dysplasia were immunohistochemically stained with p16, ALDH1, CD44, SOX2, and OCT4, respectively.ResultsExpression of ALDH1 and SOX2 was significantly increased in OED cases, whereas CD44 and OCT4 expression was increased in normal mucosa. P16-positive OED cases showed upregulation of ALDH1 and OCT4 expression as compared to p16-negative cases, while CD44 and SOX2 expression was downregulated in p16-positive OED cases; however, the results were not statistically significant.ConclusionThe present study indicated a suggestive link between p16 and cancer stem cell marker expression in HPV-associated OED, and that p16 has a significant role in CSC progression in OED. This is the first study to evaluate the expression of putative CSC markers in HPV-associated OED. However, low study numbers are a potential limiting factor in this study.

Non-stem bladder cancer cell-derived extracellular vesicles promote cancer stem cell survival in response to chemotherapy

BackgroundChemosenstive non-stem cancer cells (NSCCs) constitute the bulk of tumors and are considered as part of the cancer stem cell (CSC) niche in the tumor microenvironment (TME). Tumor-derived extracellular vesicles (EVs) mediate the communication between tumors and the TME. In this study, we sought to investigate the impacts of EVs released by NSCCs on the maintenance of CSC properties and chemoresistance.MethodsWe employed murine MB49 bladder cancer (BC) sub-lines representing CSCs and NSCCs as a model system. Chemotherapy drugs were used to treat NSCCs in order to collect conditioned EVs. The impacts of NSCC-derived EVs on CSC progression were evaluated through sphere formation, cytotoxicity, migration, and invasion assays, and by analyzing surface marker expression on these BC cells. Differential proteomic analyses were conducted to identify cargo protein candidates involved in the EV-mediated communication between NSCCs and CSCs.ResultsNSCC-derived EVs contained cargo proteins enriched in proteostasis-related functions, and significantly altered the development of CSCs such that they were more intrinsically chemoresistant, aggressive, and better able to undergo self-renewal.ConclusionsWe thus identified a novel communication mechanism whereby NSCC-EVs can alter the relative fitness of CSCs to promote disease progression and the acquisition of chemoresistance.

Targeting the Tumor Extracellular Matrix by the Natural Molecule 4-Methylumbelliferone: A Complementary and Alternative Cancer Therapeutic Strategy.

In antineoplastic therapy, one of the challenges is to adjust the treatment to the needs of each patient and reduce the toxicity caused by conventional antitumor strategies. It has been demonstrated that natural products with antitumoral properties are less toxic than chemotherapy and radiotherapy. Also, using already developed drugs allows developing substantially less costly methods for the discovery of new treatments than traditional drug development. Candidate molecules proposed for drug repositioning include 4-methylumbelliferone (4-MU), an orally available dietetic product, derivative of coumarin and mainly found in the plant family Umbelliferae or Apiaceae. 4-MU specifically inhibits the synthesis of glycosaminoglycan hyaluronan (HA), which is its main mechanism of action. This agent reduces the availability of HA substrates and inhibits the activity of different HA synthases. However, an effect independent of HA synthesis has also been observed. 4-MU acts as an inhibitor of tumor growth in different types of cancer. Particularly, 4-MU acts on the proliferation, migration and invasion abilities of tumor cells and inhibits the progression of cancer stem cells and the development of drug resistance. In addition, the effect of 4-MU impacts not only on tumor cells, but also on other components of the tumor microenvironment. Specifically, 4-MU can potentially act on immune, fibroblast and endothelial cells, and pro-tumor processes such as angiogenesis. Most of these effects are consistent with the altered functions of HA during tumor progression and can be interrupted by the action of 4-MU. While the potential advantage of 4-MU as an adjunct in cancer therapy could improve therapeutic efficacy and reduce toxicities of other antitumoral agents, the greatest challenge is the lack of scientific evidence to support its approval. Therefore, crucial human clinical studies have yet to be done to respond to this need. Here, we discuss and review the possible applications of 4-MU as an adjunct in conventional antineoplastic therapies, to achieve greater therapeutic success. We also describe the main proposed mechanisms of action that promote an increase in the efficacy of conventional antineoplastic strategies in different types of cancer and prospects that promote 4-MU repositioning and application in cancer therapy.

CDK1 promotes the stemness of lung cancer cells through interacting with Sox2.

The promoting roles of cyclin dependent kinase 1 (CDK1) have been revealed in various tumors, however, its effects in the progression of cancer stem cells are still confusing. This work aims to explore the roles of CDK1 in regulating the stemness of lung cancer cells. Online dataset analysis was performed to evaluate the correlation between CDK1 exression and the survival of lung cancer patients. RT-qPCR, western blot, cell viability, sphere-formation analysis and ALDH activity detection were used to investigate the roles of CDK1 on lung cancer cell stemness, viability and chemotherapeutic sensitivity. Immunocoprecipitation (Co-IP) analysis and rescuing experiments were performed to reveal the underlying mechanisms contributing to CDK1-mediated effects on lung cancer cell stemness. CDK1 mRNA expression was negatively correlated with the overall survival of lung cancer patients and remarkably increased in tumor spheres formed by lung cancer cells compared to the parental cells. Additionally, CDK1 positively regulated the stemness of lung cancer cells. Mechanistically, CDK1 could interact with Sox2 protein, but not other stemness markers (Oct4, Nanog and CD133). Furthermore, CDK1 increased the phosphorylation, cytoplasm-nuclear translocation and transcriptional activity of Sox2 protein in lung cancer cells. Moreover, CDK1 positively regulated the stemness of lung cancer cells in a Sox2-dependent manner. Finally, we revealed that inhibition of CDK1 enhanced the chemotherapeutic sensitivity, which was also rescued by Sox2 overexpression. This work reveals a novel CDK1/Sox2 axis responsible for maintaining the stemness of lung cancer cells.

Abstract PS16-28: Runx3 regulates emt during development lapatinib resistance

Abstract RUNX3 regulates EMT during development lapatinib resistanceBackground: Lapatinib is a small molecular inhibitor of HER2 and EGFR tyrosine kinase, which is used for HER2 positive metastatic breast cancer patients. However, significant proportion of patients relapse due to acquired resistance. The epithelial to mesenchymal transition (EMT), which induces cell migration, invasion and cancer stem cell progression, was one of the mechanism that confers to drug resistance. We determined the correlation of lapatinib resistance and EMT, and identified a regulatory factor of EMT which associated with the development process of acquired lapatinib resistance.Methods: Acquired lapatinib resistant SK-BR-3 (SK-BR-3 LR) cells were established by continuously exposing to lapatinib for 7 months. The sensitivity of lapatinib was confirmed by MTT assay. Cell cycle progression was verified using flow cytometry analysis. Expression of signal transduction molecules were determined using quantitative PCR, western blotting and transcriptome data analysis. Cell migration and invasion ability were verified using wound healing assay and Boyden chamber assay. siRNA knock-down system were used for further analysis. Results: Lapatinib resistant (SK-BR-3 LR) cells showed aggressive morphology compared with parental cells. The growth rate and cell cycle progression were increased in SK-BR-3 LR cells. Expression of Snail, Vimentin, SOX2, Nanog, TGF-b1 and Smad proteins increased in SK-BR-3 LR cells. In SK-BR-3 LR cells, cell migration and invasion were significantly increased. Correlated with a promoter methylation of RUNX3, expression of RUNX3 was down-regulated in SK-BR-3 LR cells. In Runx3 knock-down cells TGF-b1, SOX2, smad molecules were up-regulated. Conclusion: SK-BR-3 LR cells showed aggressive phenotype. Expression of EMT markers, cancer stem cell markers, TGF-β pathway associated molecules and Smad proteins were increased in SK-BR-3 LR cells. Also, the increase of cell migration and invasion was observed in LR cells. RUNX3 affected to cell migration and invasion through regulation of EMT associated molecules. Therefore, RUNX3 might be a specified molecule, which partially contributes resistance to lapatinib through regulates EMT. Citation Format: So Hyeon Kim, Ahrum Min, Seongyeong Kim, Yoonjung Park, Yu Jin Kim, Seock-Ah Im. Runx3 regulates emt during development lapatinib resistance [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS16-28.

Abstract 694: PAWI-2 overcomes tumor stemness and drug resistance in pancreatic cancer stem cells

Abstract Today, pancreatic cancer (PC) remains a major health problem in the US and soon will be the second most common cause of mortality due to cancer. However, most of the front-line PC chemotherapies cause serious side effects and a majority of patients with PC are often resistant to clinical therapies. The fact that cancer stem cells (CSCs) become enriched after anti-cancer therapy implicates CSCs as key contributors to tumor dormancy, metastasis, and relapse in PC. Given the important role of human pancreatic cancer stem cells (hPCSCs) in PC, development of a novel treatment strategy that targets hPCSCs or their extrinsic and intrinsic regulators could be of great clinical utility to treat PC. Herein, we used a highly validated hPCSCs model (FGβ3 cells) to test a novel compound (PAWI-2) to target CSCs. In this hPCSC model, integrin αvβ3 expression was shown to be a marker/functional contributor to CSC progression and drug resistance attributed to its ability to trigger anchorage-independent cell survival and tumor metastasis. Specifically, integrin αvβ3 recruits KRAS and RalB to tumor cell plasma membranes to activate NF-κB signaling that triggers dysregulated KRAS-RalB-NF-κB pathways. This was shown to be a pharmacological target to reverse CSC-like properties or re-sensitize drug resistance (e.g., EGFR inhibitors, erlotinib) of established FGβ3 tumors. Compared to parental FG cells, PAWI-2 showed greater potency to inhibit cell viability and self-renewal capacity of FGβ3 cells. PAWI-2 inhibited dysregulated integrin β3-KRAS-RalB-NF-κB signaling independent of KRAS and Ral. This is clinically relevant because >90% of KRAS is activated by mutations in PC and RAS or Ral inhibitors have not proven effective clinically. PAWI-2 targeted downstream of KRAS signaling and was negatively regulated by other feedback mechanisms. This was further shown by genetic knockdown of key regulator and co-treatment of specific inhibitors. PAWI-2 overcomes erlotinib resistance in FGβ3 cells with greater potency than bortezomib. In the proposed mechanism of PAWI-2 action, key regulators link the inhibition of KRAS signaling and cell cycle arrest (G2/M). The great utility and pharmacological potency of PAWI-2 in FGβ3 cells (that possess stem-like properties) compared to FG cells provide a basis for further development. PAWI-2 as an efficient therapeutic to reverse tumor stemness and resensitize CSC tumors to drug inhibition. This work was supported by Inception Award from California Institute for Regenerative Medicine (CIRM) (DISC1-10583; J.R. Cashman) and by funds from the Human BioMolecular Research Institute. Citation Format: Jiongjia Cheng, John Cashman, Jorge Gomez-Galeno. PAWI-2 overcomes tumor stemness and drug resistance in pancreatic cancer stem cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 694.

Abstract C109: Modulation of HDAC activity in subtypes of triple-negative breast cancer: Effects of vorinostat on HDAC 7 expression and cancer stem cells progression

Abstract Epigenetic drugs, such as histone deacetylase inhibitors (HDACi), are continuing to emerge as promising therapies for various cancers. These drugs, including FDA-approved vorinostat, are capable of multiple actions and considered to be multifunctional. Histone deacetylases (HDAC) are chromatin-modifying enzymes that are involved in various cellular events, such as tissue differentiation, autophagy, apoptosis, migration, mitosis and angiogenesis. High levels of HDACs have been detected in several cancers. Early studies in our laboratory showed different effects by vorinostat on global HDAC activity in several triple-negative breast cancer (TNBC) subtypes. This study focused on HDAC 7, which has been associated with increases in cancer stem cells and poor prognosis. Cancer stem cells play an important role in cancer resistance to therapy. Histone deacetylase inhibitors are emerging as therapy for triple-negative breast cancer, which is currently an unmet need in women's health due to the lack of targeted therapies. This study investigated the effects of vorinostat on apoptosis and the modulation of HDAC 7 expression in two subtypes of triple-negative breast cancers, MB231(MSL) and HCC70 (BL-2). Using caspase 3/7 assays vorinostat induced apoptosis. Additionally, flow cytometry and immunostaining were conducted to determine vorinostat's effects on expression of two cancer stem cell (CSC) markers, CD44 and CD24. Western blot and real-time PCR showed a significant decrease (10-fold) in the expression of HDAC 7 by vorinostat in HCC70 cells. A modest decrease (3-fold) was also observed in MB231 cells. CD44 expression was deceased by vorinostat in MB231 cells. This study demonstrated that vorinostat exerts its anticancer effects through several mechanisms, such as inducing apoptosis, downregulating HDAC 7 and decreasing cancer stem cells. This therapy could be beneficial for subtypes of TNBC, such as HCC70, an aggressive basal-like 2 cell line from an African American. Citation Format: Fatemeh Nouri Emamzadeh, Anfernee Hawkins, Gustavo Miranda-Carboni, Rhonda Moore, Beverly Word, Beverly Lyn-Cook. Modulation of HDAC activity in subtypes of triple-negative breast cancer: Effects of vorinostat on HDAC 7 expression and cancer stem cells progression [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C109.

Hypoxia, Inflammation and Necrosis as Determinants of Glioblastoma Cancer Stem Cells Progression.

Tumor hypoxic microenvironment causes hypoxia inducible factor 1 alpha (HIF-1α) activation and necrosis with alarmins release. Importantly, HIF-1α also controls the expression of alarmin receptors in tumor cells that can bind to and be activated by alarmins. Human tumor tissues possess 1–2% of cancer stem cells (CSCs) residing in hypoxic niches and responsible for the metastatic potential of tumors. Our hypothesis is that hypoxic CSCs express alarmin receptors that can bind alarmins released during necrosis, an event favoring CSCs migration. To investigate this aspect, glioblastoma stem-like cell (GSC) lines were kept under hypoxia to determine the expression of hypoxic markers as well as receptor for advanced glycation end products (RAGE). The presence of necrotic extracts increased migration, invasion and cellular adhesion. Importantly, HIF-1α inhibition by digoxin or acriflavine prevented the response of GSCs to hypoxia alone or plus necrotic extracts. In vivo, GSCs injected in one brain hemisphere of NOD/SCID mice were induced to migrate to the other one in which a necrotic extract was previously injected. In conclusion, our results show that hypoxia is important not only for GSCs maintenance but also for guiding their response to external necrosis. Inhibition of hypoxic pathway may therefore represent a target for preventing brain invasion by glioblastoma stem cells (GSCs).

MicroRNA-495 confers inhibitory effects on cancer stem cells in oral squamous cell carcinoma through the HOXC6-mediated TGF-\u03b2 signaling pathway

BackgroundOral squamous cell carcinoma (OSCC) is associated with high morbidity and ranks sixth among malignancies worldwide. Increasing evidence suggests that microRNAs (miRNAs or miRs) play a critical role in regulating cancer stem cells (CSCs), which drive the proliferation and spread of OSCC. Therefore, based on the alteration of aberrantly expressed miR-495 and homeobox C6 (HOXC6) by Gene Expression Omnibus (GEO) analysis, we subsequently explore the potential effect of miR-495 on the progression of CSCs in OSCC.MethodsAfter the isolation of CSCs from the clinical tissue samples of OSCC patients, the expression of miR-495 and HOXC6 was determined, followed by the validation of the relationship between miR-495 and HOXC6. Subsequently, gain- and loss-function approach was performed to detect the role of miR-495 and HOXC6 in cell proliferation, migration, invasion, cell cycle entry, apoptosis, and epithelial-mesenchymal transition (EMT) of CSCs in OSCC, as well as the tumor growth in vivo.ResultsHOXC6 was highly expressed while miR-495 was poorly expressed in OSCC. HOXC6 was verified to be a target gene of miR-495, and miR-495 could inhibit the activation of the TGF-β signaling pathway. CSCs with miR-495 overexpression or HOXC6 silencing exhibited reversed EMT process; reduced abilities of proliferation, migration, and invasion; and promoted cell apoptosis in vitro. Moreover, inhibited tumor growth was observed in vivo after injection with miR-495 agomir or sh-HOXC6. In contrast, the downregulation of miR-495 showed an induced role in the progression of OSCC.ConclusionThese findings suggest that miR-495 may suppress HOXC6 to inhibit EMT, proliferation, migration, and invasion while promoting apoptosis of CSCs in OSCC by inhibiting the TGF-β signaling pathway.

Role of integrin β1 as a biomarker of stemness in head and neck squamous cell carcinoma

ObjectivesSignaling between cancer stem cells (CSC) and their extracellular matrix has a crucial role in CSC progression and maintenance. However, mediators of this signaling pathway in head and neck squamous cell carcinoma (HNSCC) are largely unknown. Here, we explored whether integrin β1, which is one of the key regulators of the communication between cells and their microenvironment, affected the stemness of HNSCC cells. Materials and methodsWe examined self-renewal capacity, chemoresistance, and xenograft tumorigenicity after knockdown of integrin β1 in primary HNSCC cells. In addition, we studied the role of focal adhesion kinase (FAK), an intracellular downstream molecule of integrin signaling, in influencing stemness of HNSCC. The relevance of Notch1 and integrin β1 interactions in HNSCC cells was also examined. Finally, immunohistochemical analysis was carried out to test whether the coexpression of integrin β1 and Notch1 in the samples from HNSCC patients correlated with their survival. ResultsTargeting integrin β1 in HNSCC cells inhibited self-renewal, chemoresistance, and in vivo tumor-forming capacity. Treatment with an inhibitor of FAK decreased self-renewal capacities and expression of various putative stem cell markers (Oct4, Sox2, and Nanog) in a dose-dependent manner. Moreover, knockdown of integrin β1 decreased the expression of Notch1 and its target genes (Hey1 and Hes1). Notably, HNSCC patients demonstrating simultaneous expression of integrin β1 and Notch1 in their tissue samples had significantly worse survival rate. ConclusionIntegrin β1/Notch1 axis has a significant role in the regulation of stemness in HNSCC.

THE RADIOTHERAPY MIGHT BE A VACCINE FOR IMMMUN RESPONSE

Radiotherapy (RT) is one of the most important treatment options of cancer and also may activates immun response. Because of this we must discuss the question of “is the radiotherapy vaccine”. If RT increases the immun response we must learn some more about the RT effects on the cells, cell surface antigene, immun checkpoints and their inhibition (ICI; CTLA4, PD1, PDL1 inhibition) . It will be discussed the role of the radiotherapy and biologic effects of the radiotherapy to activate the immun response, radiotherapy dose, radiotherapy timing and the side effects of immun checkpoints inhibitors. But with high conformal hypofractionated stereotactic radiotherapy the microenvironment around the cancer tissue such as fibroblast may survives and then may helps cancer stem cell progression.

HIF‑1α promotes the stemness of oesophageal squamous cell carcinoma by activating the Wnt/β‑catenin pathway.

Hypoxia‑inducible‑factor 1α (HIF‑1α) is a marker for poor prognosis in the majority of the cancer types, and it has been revealed to be essential for maintaining cancer stem cells (CSCs). In the present study, it was determined that the expression of HIF‑1α and CSC‑related genes under hypoxic conditions was upregulated. Stable knockdown of HIF‑1α significantly inhibited cell proliferation, migration and tumour growth in vivo in oesophageal squamous cell carcinoma (ESCC). A previous study revealed that the Wnt/β‑catenin pathway may play a key role in maintenance and progression of CSCs. Therefore, it was also revealed that stable knockdown of HIF‑1α reduced the formation of spheroid body cells, the expression of CSC‑related genes and Wnt/β‑catenin pathway‑related target genes, as well as the activity of the Wnt/β‑catenin pathway. Collectively, the present results indicated that HIF‑1α may regulate the stemness of ESCC by activating the Wnt/β‑catenin pathway.

Diallyl Disulfide Inhibits Breast Cancer Stem Cell Progression and Glucose Metabolism by Targeting CD44/PKM2/AMPK Signaling.

It has been reported that diallyl disulfide (DADS) has anti-proliferative activity in many cancers. The purpose of this study was to investigate the functions of DADS and the underlying mechanisms of its effect in breast cancer stem cells (BCSCs). Mammosphere formation assay, glucose consumption assay, lactate production assay and mouse xenograft experiments were performed to explore the functions of DADS in BCSCs. ATPase activity assay, western blotting and immunohistochemistry (IHC) assay were conduct to explore the mechanisms underlying the effects of DADS in BCSCs. The results showed that DADS suppressed cell stemness and glucose metabolism in BCSCs. In vivo mouse xenograft experiments showed that DADS inhibited the proliferation and metastasis of BCSCs. Then, we continued to explore the mechanisms underlying the effects of DADS in BCSCs and found that DADS acts by targeting CD44, Pyruvate kinase M2 (PKM2) and AMP-activated protein kinase (AMPK) signaling pathways. IHC analysis of 125 breast cancer patients' tissues demonstrated that CD44, PKM2 and AMPK expression levels were positively correlated. In addition, positive CD44, PKM2 and AMPK expression was associated with poor patient overall survival (OS) and disease-free survival (DFS). In summary, DADS suppresses cell stemness, proliferation, metastasis and glucose metabolism in BCSCs partly through the inhibition of CD44/PKM2/AMPK. DADS may be used as a potential therapy for breast cancer treatment.