Role of cancer stem cell ecosystem on breast cancer metastasis and related mouse models

Breast cancer metastasis is responsible for most breast cancer-related deaths and is influenced by many factors within the tumor ecosystem,including tumor cells and microenvironment.Breast cancer stem cells(BCSCs)constitute a small population of cancer cells with unique characteristics,including their capacity for self-renewal and differentiation.Studies have shown that BCSCs not only drive tumorigenesis but also play a crucial role in promoting metastasis in breast cancer.The tumor microenvironment(TME),composed of stromal cells,immune cells,blood vessel cells,fibroblasts,and microbes in proximity to cancer cells,is increasingly recognized for its crosstalk with BCSCs and role in BCSC survival,growth,and dissemination,thereby influencing metastatic ability.Hence,a thorough understanding of BCSCs and the TME is critical for unraveling the mechanisms underlying breast cancer metastasis.In this review,we summarize current knowledge on the roles of BCSCs and the TME in breast cancer metastasis,as well as the underlying regulatory mechanisms.Furthermore,we provide an overview of relevant mouse models used to study breast cancer metastasis,as well as treatment strategies and clinical trials addressing BCSC-TME interactions during metastasis.Overall,this study provides valuable insights for the development of effective therapeutic strategies to reduce breast cancer metastasis.

Effect of colorectal cancer stem cells on the development and metastasis of colorectal cancer

The relevant mechanism of tumor-associated macrophages(TAMs)in the treatment of colorectal cancer patients with immune checkpoint inhibitors(ICIs)is discussed,and the application prospects of TAMs in reversing the treatment tolerance of ICIs are discussed to provide a reference for related studies.As a class of drugs widely used in clinical tumor immunotherapy,ICIs can act on regulatory molecules on cells that play an inhibitory role-immune checkpoints-and kill tumors in the form of an immune response by activating a variety of immune cells in the immune system.The sensitivity of patients with different types of colorectal cancer to ICI treatment varies greatly.The phenotype and function of TAMs in the colorectal cancer microenvironment are closely related to the efficacy of ICIs.ICIs can regulate the phenotypic function of TAMs,and TAMs can also affect the tolerance of colorectal cancer to ICI therapy.TAMs play an important role in ICI resistance,and making full use of this target as a therapeutic strategy is expected to improve the immunotherapy efficacy and prognosis of patients with colorectal cancer.

Multifaceted role of microRNAs in gastric cancer stem cells: Mechanisms and potential biomarkers

MicroRNAs(miRNAs)have received much attention in the past decade as potential key epigenomic regulators of tumors and cancer stem cells(CSCs).The abnormal expression of miRNAs is responsible for different phenotypes of gastric cancer stem cells(GCSCs).Some specific miRNAs could be used as promising biomarkers and therapeutic targets for the identification of GCSCs.This review summarizes the coding process and biological functions of miRNAs and demon-strates their role and efficacy in gastric cancer(GC)metastasis,drug resistance,and apoptosis,especially in the regulatory mechanism of GCSCs.It shows that the overexpression of onco-miRNAs and silencing of tumor-suppressor miRNAs can play a role in promoting or inhibiting tumor metastasis,apart from the initial formation of GC.It also discusses the epigenetic regulation and potential clinical applications of miRNAs as well as the role of CSCs in the pathogenesis of GC.We believe that this review may help in designing novel therapeutic approaches for GC.

Prostaglandin D2 regulation of autophagy affects stemness of gastric cancer stem cells

Objective:To explore the effect and mechanism of prostaglandins D2(PGD2)on the stemness of gastric cancer stem cells(GCSCs).Methods:7901-GCSCs were enriched by serum-free culture method;then the positivity rate of CD44,a stemness marker,was detected by flow cytometry in serum-free cultured 7901-GCSCs;the sphere-forming ability was detected by the sphere-forming assay after stimulation with different concentrations of PGD2(2.5,5,10)μg/mL,and the expression of stemness-related indicators(OCT4,CD44)and autophagyrelated proteins(LC3,Beclin-1)after PGD2 stimulation was detected by the western blot assay in different concentrations.The expression of stemness-related indexes(OCT4,CD44)and autophagy-related proteins(LC3,Beclin-1)were detected by Western blot assay after stimulation with different concentrations of PGD2.The expression of autophagy-related proteins after stimulation with different concentrations of CQ(2.5,5,10)μM was detected by Western blot experiment.The protein expression of autophagy-related proteins(LC3,Beclin-1)and stemness-related indexes(OCT4,CD44)was detected by Western blot experiment after PGD2 as well as PGD2+CQ treatment.Results:Flow cytometry results showed that the expression of CD44 positivity was increased in serum-free cultured 7901-GCSCs compared with gastric cancer cells SGC-7901(P<0.05),which fulfilled the needs of subsequent experiments.The results of stem cell spheroid formation assay showed that the spheroid formation ability of 7901-GCSCs in the PGD2 group was significantly weakened compared with that of the DMSO group(P<0.05).Western blot results showed that the protein expression of stemness-related indexes(OCT4,CD44)was down-regulated in the 7901-GCSCs in the PGD2 group compared with that of the DMSO group(P<0.05),and the expression of autophagy-related proteins(LC3,Beclin-1)expression increased(P<0.05).Compared with the DMSO group,the expression of autophagy-related proteins(LC3,Beclin-1)was decreased in the CQ group(P<0.05).Western blot results also showed that the expression of cellular autophagy-related proteins and stemness-related indexes in the PGD2+CQ group was not significantly changed compared with that of the DMSO group(ns:the difference was not significant),suggesting that the CQ could block the effect of PGD2 on the expression of stemness markers in 7901-GCSCs.7901-GCSCs stemness inhibition.Conclusion:PGD2 may affect the stemness of 7901-GCSCs by regulating autophagy.

Research Progress of Breast Cancer Stem Cell Stemness and Breast Cancer Recurrence

Currently, breast cancer is the most common malignant tumour in Chinese women with a high incidence rate, and recurrence and metastasis are the main reasons affecting survival. Breast Cancer Stem Cells (BCSCs) are stem cells capable of continuous regeneration in vivo with strong self-renewal ability and multidirectional differentiation potential, which are highly tumourigenic and insensitive to radiotherapy and chemotherapy, and are highly susceptible to breast cancer recurrence. Therefore, exploring the stemness of BCSCs and their mechanism associated with recurrence is important for developing new therapeutic strategies, improving therapeutic efficacy, and improving patient prognosis.

Research progress on lung cancer stem cells in epidermal growth factor receptor–tyrosine kinase inhibitor targeted therapy resistance in lung adenocarcinoma

Lung cancer is the leading cause of cancer-related deaths globally.In recent years,with the widespread use of genetic testing,epidermal growth factor receptor–tyrosine kinase inhibitor(EGFR-TKI)–targeted drugs have been efficacious to patients with lung adenocarcinoma exhibiting EGFR mutations.However,resistance to treatment is inevitable and eventually leads to tumor progression,recurrence,and reduction in the overall treatment efficacy.Lung cancer stem cells play a crucial role in the development of resistance toward EGFR-TKI–targeted therapy for lung adenocarcinoma.Lung cancer stem cells possess self-renewal,multilineage differentiation,and unlimited proliferation capabilities,which efficiently contribute to tumor formation and ultimately lead to tumor recurrence andmetastasis.In this study,we evaluated the origin,markers,stemness index,relevant classic studies,resistance mechanisms,related signaling pathways,and strategies for reversing lung cancer stem cell resistance to EGFR-TKIs to provide new insights on delaying or reducing resistance and to improve the treatment efficacy of patients with EGFR-mutated lung adenocarcinoma in the future.

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.

Advancing Cancer Stem Cell-Targeted Therapeutic Applications

Cancer stem cells(CSCs),first identified in blood cancers,are increasingly recognized as significant biomarkers and targets in tumor therapy due to their metastatic potential and role in cancer recurrence.Recent research has demonstrated the dedication of scientists in targeting CSCs to explore novel therapeutic strategies.Many types of cancer exhibit metastasis,heterogeneity,and resistance to treatment,all of which are influenced by CSCs.These cells utilize various transcription factors and signaling pathways to carry out these functions.By identifying and understanding these pathways,new therapeutic breakthroughs can be achieved.Thus,targeting cancer stem cells holds great potential and importance in cancer treatment.Moreover,CSCs offer promising avenues for treating otherwise incurable diseases.However,targeting CSCs presents challenges such as immunological rejection and disease recurrence.Advancing research into CSCs may reveal new insights in the fight against cancer and ultimately improve human health.This review explores the roles of CSCs in cancer development and treatment,aiming to uncover new therapeutic approaches.

Therapeutic implications of cancer stem cells in prostate cancer

Prostate cancer, one of the most frequently occurring cancers in men, is a heterogeneous disease involving multiple cell types within tumors. This tumor heterogeneity at least partly results from genomic instability leading to sub-clonal cellular differentiation. The differentiated cell populations originate from a small subset of cells with tumor-initiating and stem-like properties. These cells, termed prostate cancer stem cells(PCSCs), play crucial roles in disease progression, drug resistance, and relapse. This review discusses the origin, hierarchy, and plasticity of PCSCs;methods for isolation and enrichment of PCSCs;and various cellular and metabolic signaling pathways involved in PCSC induction and maintenance, as well as therapeutic targeting.

Cancer stem cells: a target for overcoming therapeutic resistance and relapse

Cancer stem cells(CSCs) are a small subset of cells in cancers that are thought to initiate tumorous transformation and promote metastasis, recurrence, and resistance to treatment. Growing evidence has revealed the existence of CSCs in various types of cancers and suggested that CSCs differentiate into diverse lineage cells that contribute to tumor progression. We may be able to overcome the limitations of cancer treatment with a comprehensive understanding of the biological features and mechanisms underlying therapeutic resistance in CSCs. This review provides an overview of the properties, biomarkers, and mechanisms of resistance shown by CSCs. Recent findings on metabolic features, especially fatty acid metabolism and ferroptosis in CSCs, are highlighted, along with promising targeting strategies. Targeting CSCs is a potential treatment plan to conquer cancer and prevent resistance and relapse in cancer treatment.

Ardisia gigantifolia ethanolic extract inhibits cell proliferation and targets cancer stem cells in gastric cancer

Objective:To evaluate the effects of ethanol extract from Ardisia gigantifolia leaves on cell proliferation and cancer stem cell(CSC)number in gastric cancer.Methods:The inhibitory effect of Ardisia gigantifolia extract on the proliferation of MKN45 and MKN74 gastric cancer cells was assessed using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay.Non-adherent culture(3D)model was used to evaluate the effect of the extract on tumorsphere size and number.Moreover,the expression of CD44,ALDH,and p21 was determined by immunofluorescence analysis.Flow cytometric analysis was performed to evaluate cell cycle arrest and the expression of gastric CSC markers CD44 and ALDH.Real-time PCR analysis was also carried out to assess the effect of the extract on the expression of cell cycle-regulated genes.Results:Ardisia gigantifolia extract effectively inhibited cell proliferation with an IC_(50)of 55.7μg/m L in MKN45 cells and 123.6μg/m L in MKN74 cells.The extract also arrested cell cycle in the G_(0)/G_(1)phase as well as significantly reduced the size and number of tumorspheres.The markedly increased expression of p21 was observed at both m RNA and protein levels in the extract-treated adherent cells and tumorspheres.In addition,Ardisia gigantifolia extract significantly reduced the number of CD44-and/or ALDH-expressing gastric CSC.Conclusions:The development of gastric CSC can be inhibited by the ethanol extract of Ardisia gigantifolia.

Advances of nanotechnology applied to cancer stem cells

Cancer stem cells(CSCs)are a small proportion of the cells that exist in cancer tissues.They are considered to be the culprit of tumor genesis,development,drug resistance,metastasis and recurrence because of their self-renewal,proliferation,and differentiation potential.The elimination of CSCs is thus the key to cure cancer,and targeting CSCs provides a new method for tumor treatment.Due to the advantages of controlled sustained release,targeting and high biocompatibility,a variety of nanomaterials are used in the diagnosis and treatments targeting CSCs and promote the recognition and removal of tumor cells and CSCs.This article mainly reviews the research progress of nanotechnology in sorting CSCs and nanodrug delivery systems targeting CSCs.Furthermore,we identify the problems and future research directions of nanotechnology in CSC therapy.We hope that this review will provide guidance for the design of nanotechnology as a drug carrier so that it can be used in clinic for cancer therapy as soon as possible.

Molecular signaling in cancer stem cells of tongue squamous cell carcinoma:Therapeutic implications and challenges

Head and neck squamous cell carcinoma is the seventh most common cancer worldwide with high mortality rates.Amongst oral cavity cancers,tongue carcinoma is a very common and aggressive oral cavity carcinoma.Despite the implementation of a multimodality treatment regime including surgical intervention,chemo-radiation as well as targeted therapy,tongue carcinoma shows a poor overall 5-year survival pattern,which is attributed to therapy resistance and recurrence of the disease.The presence of a rare population,i.e.,cancer stem cells(CSCs)within the tumor,are involved in therapy resistance,recurrence,and distant metastasis that results in poor survival patterns.Therapeutic agents targeting CSCs have been in clinical trials,although they are unable to reach into therapy stage which is due to their failure in trials.A more detailed understanding of the CSCs is essential for identifying efficient targets.Molecular signaling pathways,which are differentially regulated in the CSCs,are one of the promising targets to manipulate the CSCs that would provide an improved outcome.In this review,we summarize the current understanding of molecular signaling associated with the maintenance and regulation of CSCs in tongue squamous cell carcinoma in order to emphasize the need of the hour to get a deeper understanding to unravel novel targets.

Targeting the mechano-microenvironment and liver cancer stem cells:a promising therapeutic strategy for liver cancer

Over the past 2 decades,cancer stem cells(CSCs)have been identified as the root cause of cancer occurrence,progression,chemoradioresistance,recurrence,and metastasis.Targeting CSCs is a novel therapeutic strategy for cancer management and treatment.Liver cancer(LC)is a malignant disease that can endanger human health.Studies are increasingly suggesting that changes in the liver mechanical microenvironment are a primary driver triggering the occurrence and development of liver cancer.In this review,we summarize current understanding of the roles of the liver mechano-microenvironment and liver cancer stem cells(LCSCs)in liver cancer progression.We also discuss the relationship between the mechanical heterogeneity of liver cancer tissues and LCSC recruitment and metastasis.Finally,we highlight potential mechanosensitive molecules in LCSCs and mechanotherapy in liver cancer.Understanding the roles and regulatory mechanisms of the mechano-microenvironment and LCSCs may provide fundamental insights into liver cancer progression and aid in further development of novel therapeutic strategies.

Biomimetic biomineralization nanoplatform-mediated differentiation therapy and phototherapy for cancer stem cell inhibition and antitumor immunity activation

Growing evidence suggests that the presence of cancer stem cells(CSCs)is a major challenge in current tumor treatments,especially the transition from non-CSCs to differentiation of CSCs for evading conventional therapies and driving metastasis.Here we propose a therapeutic strategy of synergistic differentiation therapy and phototherapy to induce differentiation of CSCs into mature tumor cells by differentiation inducers and synergistic elimination of them and normal cancer cells through phototherapy.In this work,we synthesized a biomimetic nanoplatform loaded with IR-780 and all-trans retinoic acid(ATRA)via biomineralization.This method can integrate aluminum ions into small-sized protein carriers to form nanoclusters,which undergo responsive degradation under acidic conditions and facilitate deep tumor penetration.With the help of CSC differentiation induced by ATRA,IR-780 inhibited the self-renewal of CSCs and cancer progression by generating hyperthermia and reactive oxygen species in a synergistic manner.Furthermore,ATRA can boost immunogenic cell death induced by phototherapy,thereby strongly causing a systemic anti-tumor immune response and efficiently eliminating CSCs and tumor cells.Taken together,this dual strategy represents a new paradigm of targeted eradication of CSCs and tumors by inducing CSC differentiation,improving photothermal therapy/photodynamic therapy and enhancing antitumor immunity.

Roles of cancer stem cells in gastrointestinal cancers

Cancer stem cells(CSCs)are the main cause of tumor growth,invasion,metastasis and recurrence.Recently,CSCs have been extensively studied to identify CSCspecific surface markers as well as signaling pathways that play key roles in CSCs self-renewal.The involvement of CSCs in the pathogenesis of gastrointestinal(GI)cancers also highlights these cells as a priority target for therapy.The diagnosis,prognosis and treatment of GI cancer have always been a focus of attention.Therefore,the potential application of CSCs in GI cancers is receiving increasing attention.This review summarizes the role of CSCs in GI cancers,focusing on esophageal cancer,gastric cancer,liver cancer,colorectal cancer,and pancreatic cancer.In addition,we propose CSCs as potential targets and therapeutic strategies for the effective treatment of GI cancers,which may provide better guidance for clinical treatment of GI cancers.

Obesity and cancer stem cells:Roles in cancer initiation,progression and therapy resistance

Obesity,the global pandemic since industrialization,is the number one lifestylerelated risk factor for premature death,which increases the incidence and mortality of various diseases and conditions,including cancer.In recent years,the theory of cancer stem cells(CSCs),which have the capacity for self-renewal,metastasis and treatment resistance,has been bolstered by increasing evidence.However,research on how obesity affects CSCs to facilitate cancer initiation,progression and therapy resistance is still in its infancy,although evidence has already begun to accumulate.Regarding the ever-increasing burden of obesity and obesity-related cancer,it is pertinent to summarize evidence about the effects of obesity on CSCs,as elucidating these effects will contribute to the improvement in the management of obesity-related cancers.In this review,we discuss the association between obesity and CSCs,with a particular focus on how obesity promotes cancer initiation,progression and therapy resistance through CSCs and the mechanisms underlying these effects.In addition,the prospect of preventing cancer and targeting the mechanisms linking obesity and CSCs to reduce cancer risk or to improve the survival of patients with cancer is considered.

Cancer stem cells: Involvement in pancreatic cancer pathogenesis and perspectives on cancer therapeutics

Pancreatic cancer is one of the most aggressive and lethal malignancies. Despite remarkable progress in understanding pancreatic carcinogenesis at the molecular level, as well as progress in new therapeutic approaches, pancreatic cancer remains a disease with a dismal prognosis. Among the mechanisms responsible for drug resistance, the most relevant are changes in individual genes or signaling pathways and the presence of highly resistant cancer stem cells(CSCs). In pancreatic cancer, CSCs represent 0.2%-0.8% of pancreatic cancer cells and are considered to be responsible for tumor growth, invasion, metastasis and recurrence. CSCs have been extensively studied as of late to identify specific surface markers to ensure reliable sorting and for signaling pathways identified to play a pivotal role in CSC self-renewal. Involvement of CSCs in pancreatic cancer pathogenesis has also highlighted these cells as the preferential targets for therapy. The present review is an update of the results in two main fields of research in pancreatic cancer, pathogenesis and therapy, focused on the narrow perspective of CSCs.

Reporter gene systems for the identification and characterization of cancer stem cells

Cancer stem cells(CSCs)are tumor cells that share functional characteristics with normal and embryonic stem cells.CSCs have increased tumor-initiating capacity and metastatic potential and lower sensitivity to chemo-and radiotherapy,with important roles in tumor progression and the response to therapy.Thus,a current goal of cancer research is to eliminate CSCs,necessitating an adequate phenotypic and functional characterization of CSCs.Strategies have been developed to identify,enrich,and track CSCs,many of which distinguish CSCs by evaluating the expression of surface markers,the initiation of specific signaling pathways,and the activation of master transcription factors that control stemness in normal cells.We review and discuss the use of reporter gene systems for identifying CSCs.Reporters that are under the control of aldehyde dehydrogenase 1A1,CD133,Notch,Nanog homeobox,Sex-determining region Y-box 2,and POU class 5 homeobox can be used to identify CSCs in many tumor types,track cells in real time,and screen for drugs.Thus,reporter gene systems,in combination with in vitro and in vivo functional assays,can assess changes in the CSCs pool.We present relevant examples of these systems in the evaluation of experimental CSCs-targeting therapeutics,demonstrating their value in CSCs research.

Biliary tract cancer stem cells-translational options and challenges

Management of biliary tract cancer remains challenging. Tumors show high recurrence rates and therapeutic resistance, leading to dismal prognosis and short survival. The cancer stem cell model states that a tumor is a heterogeneous conglomerate of cells, in which a certain subpopulation of cells-the cancer stem cells-possesses stem cell properties. Cancer stem cells have high clinical relevance due to their potential contributions to development, progression and aggressiveness as well as recurrence and metastasis of malignant tumors. Consequently, reliable identification of as well as pharmacological intervention with cancer stem cells is an intensively investigated and promising research field. The involvement of cancer stem cells in biliary tract cancer is likely as a number of studies demonstrated their existence and the obvious clinical relevance of several established cancer stem cell markers in biliary tract cancer models and tissues. In the present article, we review and discuss the currently available literature addressing the role of putative cancer stem cells in biliary tract cancer as well as the connection between known contributors of biliary tract tumorigenesis such as oncogenic signaling pathways, micro-RNAs and the tumor microenvironment with cancer stem cells.