Pancreatic cancer stem cells: features and detection methods

Nanotherapeutic strategies exploiting biological traits of cancer stem cells

Cancer stem cells (CSCs) represent a distinct subpopulation of cancer cells that orchestrate cancer initiation, progression, metastasis, and therapeutic resistance. Despite advances in conventional therapies, the persistence of CSCs remains a major obstacle to achieving cancer eradication. Nanomedicine-based approaches have emerged for precise CSC targeting and elimination, offering unique advantages in overcoming the limitations of traditional treatments. This review systematically analyzes recent developments in nanomedicine for CSC-targeted therapy, emphasizing innovative nanomaterial designs addressing CSC-specific challenges. We first provide a detailed examination of CSC biology, focusing on their surface markers, signaling networks, microenvironmental interactions, and metabolic signatures. On this basis, we critically evaluate cutting-edge nanomaterial engineering designed to exploit these CSC traits, including stimuli-responsive nanodrugs, nanocarriers for drug delivery, and multifunctional nanoplatforms capable of generating localized hyperthermia or reactive oxygen species. These sophisticated nanotherapeutic approaches enhance selectivity and efficacy in CSC elimination, potentially circumventing drug resistance and cancer recurrence. Finally, we present an in-depth analysis of current challenges in translating nanomedicine-based CSC-targeted therapies from bench to bedside, offering critical insights into future research directions and clinical implementation. This review aims to provide a comprehensive framework for understanding the intersection of nanomedicine and CSC biology, contributing to more effective cancer treatment modalities.

Hsa_circ_0000467 promotes colorectal cancer proliferation and stem cell characteristics by activating the TCF4/Wnt/β-catenin pathway via sponging miR-520g

This study explores the role of circ_0000467 in colorectal cancer (CRC) progression and its potential as a therapeutic target. Circ_0000467 expression was analyzed using public datasets and clinical samples from 103 CRC patients. Functional assays evaluated its influence on CRC cell proliferation, migration, and stem-like properties. Molecular interactions with miR-520g and TCF4 were examined, and in vivo experiments assessed tumor growth. Circ_0000467 was significantly overexpressed in CRC and associated with poor prognosis. Its upregulation enhanced tumor growth, invasion, epithelial-mesenchymal transition, and stem-like characteristics by increasing key markers (CD44, EpCAM, SOX2, and Nanog). Mechanistically, circ_0000467 acted as a molecular sponge for miR-520g, leading to increased TCF4 expression and activation of the Wnt/β-catenin pathway. Silencing TCF4 or overexpressing miR-520g reversed these effects. Circ_0000467 promotes CRC progression by regulating the TCF4/Wnt/β-catenin pathway through miR-520g, highlighting its potential as a biomarker and therapeutic target for CRC.

Cancer stem cells in meningiomas: novel insights and therapeutic implications

Meningiomas (MGs), which arise from meningothelial cells of the dura mater, represent a significant proportion of primary tumours of the central nervous system (CNS). Despite advances in treatment, the management of malignant meningioma (MMG) remains challenging due to diagnostic, surgical, and resection limitations. Cancer stem cells (CSCs), a subpopulation within tumours capable of self-renewal and differentiation, are highlighted as key markers of tumour growth, metastasis, and treatment resistance. Identifying additional CSC-related markers enhances the precision of malignancy evaluations, enabling advancements in personalised medicine. The review discusses key CSC biomarkers that are associated with high levels of expression, aggressive tumour behaviour, and poor outcomes. Recent molecular research has identified CSC-related biomarkers, including Oct-4, Sox2, NANOG, and CD133, which help maintain cellular renewal, proliferation, and drug resistance in MGs. This study highlights new therapeutic strategies that could improve patient prognosis with more durable tumour regression. The use of combination therapies, such as hydroxyurea alongside diltiazem, suggests more efficient and effective MG management compared to monotherapy. Signalling pathways such as NOTCH and hedgehog also offer additional avenues for therapeutic development. CRISPR/Cas9 technology has also been employed to create meningioma models, uncovering pathways related to cell growth and proliferation. Since the efficacy of traditional therapies is limited in most cases due to resistance mechanisms in CSCs, further studies on the biology of CSCs are warranted to develop therapeutic interventions that are likely to be effective in MG. Consequently, improved diagnostic approaches may lead to personalised treatment plans tailored to the specific needs of each patient.

Functional Characterization of miR-216a-5p and miR-125a-5p on Pancreatic Cancer Stem Cells

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related death. Its poor prognosis is closely related to late-stage diagnosis, which results from both nonspecific symptoms and the absence of biomarkers for early diagnosis. MicroRNAs (miRNAs) exert a regulatory role in numerous biological processes and their aberrant expression has been found in a broad spectrum of diseases, including cancer. Cancer stem cells (CSCs) represent a driving force for PDAC initiation, progression, and metastatic spread. Our previous research highlighted the interesting behavior of miR-216a-5p and miR-125a-5p related to PDAC progression and the CSC phenotype. The present study aimed to evaluate the effect of miR-216a-5p and miR-125a-5p on the acquisition or suppression of pancreatic CSC traits. BxPC-3, AsPC-1 cell lines, and their CSC-like models were transfected with miR-216a-5p and miR-125a-5p mimics and inhibitors. Following transfection, we evaluated their impact on the expression of CSC surface markers (CD44/CD24/CxCR4), ALDH1 activity, pluripotency- and EMT-related gene expression, and clonogenic potential. Our results show that miR-216a-5p enhances the expression of CD44/CD24/CxCR4 while negatively affecting the activity of ALDH1 and the expression of EMT genes. MiR-216a-5p positively influenced the clonogenic property. MiR-125a-5p promoted the expression of CD44/CD24/CxCR4 while inhibiting ALDH1 activity. It enhanced the expression of Snail, Oct-4, and Sox-2, while the clonogenic potential appeared to be affected. Comprehensively, our results provide further knowledge on the role of miRNAs in pancreatic CSCs. Moreover, they corroborate our previous findings about miR-216a-5p's potential dual role and miR-125a-5p's promotive function in PDAC.

Tumor microenvironment acidosis favors pancreatic cancer stem cell properties and in vivo metastasis

The acidic tumor microenvironment (TME) favors cancer aggressiveness via incompletely understood pathways. Here, we asked whether adaptation to environmental acidosis (pH 6.5) selects for human pancreatic cancer stem cell (CSC) properties. RNA sequencing (RNA-seq) of acid-adapted (AA) Panc-1 cells revealed CSC pathway enrichment and upregulation of CSC markers. AA Panc-1 cells exhibited classical CSC characteristics including increased aldehyde dehydrogenase (ALDH) activity and β-catenin activity. Panc-1, PaTu8988s, and MiaPaCa-2 cells all exhibited increased pancreatosphere-forming efficiency after acid adaptation but differed in CSC marker expression and did not exhibit typical flow cytometric CSC populations. However, single-nucleus sequencing revealed the acid adaptation-induced emergence of Panc-1 cell subpopulations with clear CSC characteristics. In orthotopic mouse tumors, AA Panc-1 cells exhibited enhanced aggressiveness, liver and lung metastasis, compared to controls. Collectively, our work suggests that acid adaptation enriches for pancreatic CSC phenotypes with unusual traits via several trajectories, providing new insight into how acidic microenvironments favor cancer aggressiveness.

Long non-coding RNA MIR4435-2HG modulates pancreatic cancer stem cells and chemosensitivity to gemcitabine by targeting the miR-1252-5p/STAT1

Cancer stem cells (CSCs) are key drivers of cancer progression and therapeutic resistance. Long non-coding RNAs (lncRNAs) have emerged as critical regulators of CSC properties. The aim of this study was to investigate the role of MIR4435-2HG in regulating CSC characteristics, tumorigenesis, and chemoresistance in pancreatic cancer. Functional assays were conducted to evaluate CSC self-renewal, tumorigenic potential, and chemoresistance in pancreatic cancer cells with altered expression of MIR4435-2HG. RNA interference (RNAi) was employed to knock down MIR4435-2HG, and a STAT1 reintroduction model was established to examine downstream signaling pathways. The role of miR-1252-5p as a competing endogenous RNA was also explored. Overexpression of MIR4435-2HG significantly enhanced CSC self-renewal and tumorigenic potential, whereas silencing MIR4435-2HG notably diminished these properties. Mechanistically, MIR4435-2HG promoted STAT1 expression by sponging miR-1252-5p, thereby enhancing CSC stemness and tumorigenesis. Moreover, depletion of MIR4435-2HG sensitized pancreatic cancer cells to gemcitabine-induced growth inhibition and ferroptosis. Reintroduction of STAT1 restored gemcitabine resistance in MIR4435-2HG-deficient cells. Our findings demonstrate that MIR4435-2HG plays a critical role in pancreatic cancer progression by modulating CSC properties and chemoresistance through the MIR4435-2HG/miR-1252-5p/STAT1 axis. Targeting MIR4435-2HG presents a promising therapeutic approach to regulate CSCs and improve the efficacy of chemotherapy in pancreatic cancer.

Insights and therapeutic advances in pancreatic cancer: the role of electron microscopy in decoding the tumor microenvironment

Pancreatic cancer is one of the most lethal cancers, with a 5-year overall survival rate of less than 10%. Despite the development of novel therapies in recent decades, current chemotherapeutic strategies offer limited clinical benefits due to the high heterogeneity and desmoplastic tumor microenvironment (TME) of pancreatic cancer as well as inefficient drug penetration. Antibody- and nucleic acid-based targeting therapies have emerged as strong contenders in pancreatic cancer drug discovery. Numerous studies have shown that these strategies can significantly enhance drug accumulation in tumors while reducing systemic toxicity. Additionally, electron microscopy (EM) has been a critical tool for high-resolution analysis of the TME, providing insights into the ultrastructural changes associated with pancreatic cancer progression and treatment responses. This review traces the current and technological advances in EM, particularly the development of ultramicrotomy and improvements in sample preparation that have facilitated the detailed visualization of cellular and extracellular components of the TME. This review highlights the contribution of EM in assessing the efficacy of therapeutic agents, from revealing apoptotic changes to characterizing the effects of novel compounds like ionophore antibiotic gramicidin A on cellular ultrastructures. Moreover, the review delves into the potential of EM in studying the interactions between the tumor microbiome and cancer cell migration, as well as in aiding the development of targeted therapies like antibody-drug conjugates (ADCs) and aptamer-drug conjugates (ApDCs).

Unveiling the microRNA landscape in pancreatic ductal adenocarcinoma patients and cancer cell models

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) poses a significant challenge due to late-stage diagnoses resulting from nonspecific early symptoms and the absence of early diagnostic biomarkers. MicroRNAs (miRNAs) play a crucial role in regulating diverse biological processes, and their abnormal expression is observed in various diseases, including cancer. Cancer stem cells (CSCs) are thought to act as a driving force in PDAC spread and recurrence. In pursuing the goal of unravelling the complexities of PDAC and its underlying molecular mechanisms, our study aimed to identify PDAC-associated miRNAs and relate them to disease progression, focusing on their involvement in various PDAC stages in patients and in reliable in vitro models, including pancreatic CSC (PaCSC) models.

METHODS

The miRNA profiling datasets of serum and solid biopsies of PDAC patients deposited in GEO DataSets were analyzed by REML-based meta-analysis. The panel was then investigated by Real Time PCR in serum and solid biopsies of 37 PDAC patients enrolled in the study, as well as on BxPC-3 and AsPC-1 PDAC cell lines. We extended our focus towards a possible role of PDAC-associated miRNAs in the CSC phenotype, by inducing CSC-enriched pancreatospheres from BxPC-3 and AsPC-1 PDAC cell lines and performed differential miRNA expression analysis between PaCSCs and monolayer-grown PDAC cell lines.

RESULTS

Meta-analysis showed differentially expressed miRNAs in blood samples and cancerous tissues of PDAC patients, allowing the identification of a panel of 9 PDAC-associated miRNAs. The results emerging from our patients fully confirmed the meta-analysis for the majority of miRNAs under investigation. In vitro tasks confirmed the aberrant expression of the panel of PDAC-associated miRNAs, with a dramatic dysregulation in PaCSC models. Notably, PaCSCs have shown significant overexpression of miR-4486, miR-216a-5p, and miR-216b-5p compared to PDAC cell lines, suggesting the recruitment of such miRNAs in stemness-related molecular mechanisms. Globally, our results showed a dual behaviour of miR-216a-5p and miR-216b-5p in PDAC while miR-4486, miR-361-3p, miR-125a-5p, miR-320d expression changes during the disease suggest they could promote PDAC initiation and progression.

CONCLUSIONS

This study contributed to an enhanced comprehension of the role of miRNAs in the development and progression of PDAC, shedding new light on the miRNA landscape in PDAC and its intricate interplay with CSCs, and providing specific insights useful in the development of miRNA-based diagnostic biomarkers and therapeutic targets.

Fatty acid oxidation is critical for the tumorigenic potential and chemoresistance of pancreatic cancer stem cells

BACKGROUND

We have previously demonstrated the significant reliance of pancreatic Cancer Stem Cells (PaCSCs) on mitochondrial oxidative phosphorylation (OXPHOS), which enables versatile substrate utilization, including fatty acids (FAs). Notably, dysregulated lipid scavenging and aberrant FA metabolism are implicated in PDAC progression.

METHODS & RESULTS

Our bioinformatics analyses revealed elevated expression of lipid metabolism-related genes in PDAC tissue samples compared to normal tissue samples, which correlated with a stemness signature. Additionally, PaCSCs exhibited heightened expression of diverse lipid metabolism genes and increased lipid droplet accumulation compared to differentiated progenies. Treatment with palmitic, oleic, and linolenic FAs notably augmented the self-renewal and chemotherapy resistance of CD133+ PaCSCs. Conversely, inhibitors of FA uptake, storage and metabolism reduced CSC populations both in vitro and in vivo. Mechanistically, inhibition of FA metabolism suppressed OXPHOS activity, inducing energy depletion and subsequent cell death in PaCSCs. Importantly, combining a FAO inhibitor and Gemcitabine treatment enhanced drug efficacy in vitro and in vivo, effectively diminishing the CSC content and functionality.

CONCLUSION

Targeting FAO inhibition represents a promising therapeutic strategy against this highly tumorigenic population.

PanIN and CAF transitions in pancreatic carcinogenesis revealed with spatial data integration

This study introduces a new imaging, spatial transcriptomics (ST), and single-cell RNA-sequencing integration pipeline to characterize neoplastic cell state transitions during tumorigenesis. We applied a semi-supervised analysis pipeline to examine premalignant pancreatic intraepithelial neoplasias (PanINs) that can develop into pancreatic ductal adenocarcinoma (PDAC). Their strict diagnosis on formalin-fixed and paraffin-embedded (FFPE) samples limited the single-cell characterization of human PanINs within their microenvironment. We leverage whole transcriptome FFPE ST to enable the study of a rare cohort of matched low-grade (LG) and high-grade (HG) PanIN lesions to track progression and map cellular phenotypes relative to single-cell PDAC datasets. We demonstrate that cancer-associated fibroblasts (CAFs), including antigen-presenting CAFs, are located close to PanINs. We further observed a transition from CAF-related inflammatory signaling to cellular proliferation during PanIN progression. We validate these findings with single-cell high-dimensional imaging proteomics and transcriptomics technologies. Altogether, our semi-supervised learning framework for spatial multi-omics has broad applicability across cancer types to decipher the spatiotemporal dynamics of carcinogenesis.

Multidimensional analysis of tumor stem cells: from biological properties, metabolic adaptations to immune escape mechanisms

As a key factor in tumorigenesis, progression, recurrence and metastasis, the biological properties, metabolic adaptations and immune escape mechanisms of CSCs are the focus of current oncological research. CSCs possess self-renewal, multidirectional differentiation and tumorigenicity, and their mechanisms of action can be elucidated by the clonal evolution, hierarchical model and the dynamic CSCs model, of which the dynamic model is widely recognized due to its better explanation of the function and origin of CSCs. The origin hypothesis of CSCs involves cell-cell fusion, horizontal gene transfer, genomic instability and microenvironmental regulation, which together shape the diversity of CSCs. In terms of classification, CSCs include primary CSCs (pri-CSCs), precancerous stem cells (pre-CSCs), migratory CSCs (mig-CSCs), and chemo-radiotherapy-resistant CSCs (cr-CSCs and rr-CSCs), with each type playing a specific role in tumor progression. Surface markers of CSCs, such as CD24, CD34, CD44, CD90, CD133, CD166, EpCAM, and LGR5, offer the possibility of identifying, isolating, and targeting CSCs, but the instability and heterogeneity of their expression increase the difficulty of treatment. CSCs have adapted to their survival needs through metabolic reprogramming, showing the ability to flexibly switch between glycolysis and oxidative phosphorylation (OXPHOS), as well as adjustments to amino acid and lipid metabolism. The Warburg effect typifies their metabolic profiles, and altered glutamine and fatty acid metabolism further contributes to the rapid proliferation and survival of CSCs. CSCs are able to maintain their stemness by regulating the metabolic networks to maintain their stemness characteristics, enhance antioxidant defences, and adapt to therapeutic stress. Immune escape is another strategy for CSCs to maintain their survival, and CSCs can effectively evade immune surveillance through mechanisms such as up-regulating PD-L1 expression and promoting the formation of an immunosuppressive microenvironment. Together, these properties reveal the multidimensional complexity of CSCs, underscoring the importance of a deeper understanding of the biology of CSCs for the development of more effective tumor therapeutic strategies. In the future, therapies targeting CSCs will focus on precise identification of surface markers, intervention of metabolic pathways, and overcoming immune escape, with the aim of improving the relevance and efficacy of cancer treatments, and ultimately improving patient prognosis.

Stem cell-based targeted therapy in pancreatic cancer: Current approaches and future prospects

Despite recent improvements in oncology, diagnosis, and therapy, pancreatic cancer remains extremely difficult to cure due to its aggressive growth pattern with early invasion and distant metastases, chemoresistance, and a lack of effective screening modalities for early detection. Here, novel therapeutic approaches for treating pancreatic cancer are urgently needed. Recently, stem cells have drawn a lot of interest as a possible treatment for pancreatic cancer due to their ability to locate tumors. Though research over the last few decades has revealed some very exciting and promising new treatment approaches, the clinical success of these stem-cell based anti-cancer medicines has been quite limited. The most effective stem cell-mediated therapeutic options will only be available with a deeper understanding of the intricate molecular biology underlying pancreatic cancer and the subsequent identification of cancer stem cells as a novel target that promotes the growth of the cancer and resistance to chemotherapy. This review will highlight the stem cell based anti-cancer therapy targeting pancreatic cancer stem cells and different molecular signaling pathways. A particular focus will be on the therapeutic potential of naïve Stem cells, anti-cancer drug loaded stem cells, genetically engineered stem cells and exosomal miRNA released by stem cells in pancreatic cancer treatment. Similarly, the role of nanotechnology in stem cell based anticancer therapy will be further discussed to better implementation of these cell-based cancer therapy.

Current and future immunotherapeutic approaches in pancreatic cancer treatment

Pancreatic cancer is a major cause of cancer-related death, but despondently, the outlook and prognosis for this resistant type of tumor have remained grim for a long time. Currently, it is extremely challenging to prevent or detect it early enough for effective treatment because patients rarely exhibit symptoms and there are no reliable indicators for detection. Most patients have advanced or spreading cancer that is difficult to treat, and treatments like chemotherapy and radiotherapy can only slightly prolong their life by a few months. Immunotherapy has revolutionized the treatment of pancreatic cancer, yet its effectiveness is limited by the tumor's immunosuppressive and hard-to-reach microenvironment. First, this article explains the immunosuppressive microenvironment of pancreatic cancer and highlights a wide range of immunotherapy options, including therapies involving oncolytic viruses, modified T cells (T-cell receptor [TCR]-engineered and chimeric antigen receptor [CAR] T-cell therapy), CAR natural killer cell therapy, cytokine-induced killer cells, immune checkpoint inhibitors, immunomodulators, cancer vaccines, and strategies targeting myeloid cells in the context of contemporary knowledge and future trends. Lastly, it discusses the main challenges ahead of pancreatic cancer immunotherapy.

Corosolic acid delivered by exosomes from Eriobotrya japonica decreased pancreatic cancer cell proliferation and invasion by inducing SAT1-mediated ferroptosis

BACKGROUND

In this study, we investigated whether Exo regulate the proliferation and invasion of PC.

METHODS

In this study, we isolated the Eriobotrya japonica Exo using Ultra-high speed centrifugal method. Mass spectrum were used for Exo active components analysis. PC (Capan-1 and Bxpc-3) cells proliferation, migration, and apoptosis were detected using CCK8, ethynyldeoxyuridine, transwell, wound healing, and flow cytometry analyses. We also constructed a lung metastatic mouse model and subcutaneous tumor model to illustrate the regulation effect of Exo or active components. Proteomics were used to reveal the regulatory mechanism responsible for the observed effects.

RESULTS

We isolated Eriobotrya japonica Exo and found that Exo treatment significantly suppressed cell migration and proliferation in both in vivo and in vitro using Capan-1. Mass spectrum for Exo active components analysis found that Exo contains high amounts of corosolic acid (CRA). The further study found that CRA treatment inhibit the proliferation, migration, and increased cell death of both Capan-1 and Bxpc-3 cells in a concentration-dependent manner. In vivo experiments confirmed that CRA inhibited pulmonary metastasis by decreasing the number of metastatic foci. Cell proteomics analysis showed that CRA treatment induced spermidine/spermine N1-acetyltransferase 1 (SAT1)-dependent ferroptosis. Treatment with the ferroptosis suppressor ferrostatin-1 significantly reversed CRA-induced cell apoptosis.

CONCLUSION

The data suggested that corosolic acid delivered by exosomes from Eriobotrya japonica decreased pancreatic cancer cell proliferation and invasion by inducing SAT1-mediated ferroptosis.

Safety and Effectiveness of Perioperative Hyperthermic Intraperitoneal Chemotherapy with Gemcitabine in Patients with Resected Pancreatic Ductal Adenocarcinoma: Clinical Trial EudraCT 2016-004298-41

BACKGROUND

Despite the improvement in therapies, pancreatic cancer represents one of the most cancer-related deaths. In our hypothesis, we propose that Hyperthermic Intraperitoneal Chemotherapy with gemcitabine after pancreatic cytoreductive surgery could reduce tumor progression by reducing residual neoplastic volume and residual pancreatic cancer stem cells.

MATERIALS AND METHODS

A randomized trial involving 42 patients. All patients were diagnosed with pancreatic ductal adenocarcinoma. Group I: R0 resection. Group II. R0 resection and HIPEC with gemcitabine (120 mg/m2 for 30 min). Effectiveness was measured with analysis of overall survival, disease-free survival, distant recurrence, locoregional recurrence, and measuring of pancreatic cancer stem cells (EpCAM+CXCR4+CD133+).

RESULTS

From 2017 to 2023, 63 patients were recruited for our clinical trial; 21 patients were included in each group, and 21 were excluded. Locoregional recurrence, p-value: 0.022, was lower in the experimental group. There were no significant differences between the two groups in hospital mortality, perioperative complications, or hospital costs. We found a significant decrease in pancreatic cancer stem cells in patients in the experimental group after treatment, p -value of 0.018.

CONCLUSIONS

The use of HIPEC with gemcitabine after surgery in patients with resectable pancreatic ductal adenocarcinoma reduces locoregional recurrence and may be associated with a significant decrease in pancreatic cancer stem cells.

Tumor cell stemness in gastrointestinal cancer: regulation and targeted therapy

The cancer stem cells are a rare group of self-renewable cancer cells capable of the initiation, progression, metastasis and recurrence of tumors, and also a key contributor to the therapeutic resistance. Thus, understanding the molecular mechanism of tumor stemness regulation, especially in the gastrointestinal (GI) cancers, is of great importance for targeting CSC and designing novel therapeutic strategies. This review aims to elucidate current advancements in the understanding of CSC regulation, including CSC biomarkers, signaling pathways, and non-coding RNAs. We will also provide a comprehensive view on how the tumor microenvironment (TME) display an overall tumor-promoting effect, including the recruitment and impact of cancer-associated fibroblasts (CAFs), the establishment of an immunosuppressive milieu, and the induction of angiogenesis and hypoxia. Lastly, this review consolidates mainstream novel therapeutic interventions targeting CSC stemness regulation.

Targeting signaling pathways in cancer stem cells: A potential approach for developing novel anti-cancer therapeutics

Cancer stem cells (CSCs) have emerged as prime players in the intricate landscape of cancer development, progression, and resistance to traditional treatments. These unique cellular subpopulations own the remarkable capability of self-renewal and differentiation, giving rise to the diverse cellular makeup of tumors and fostering their recurrence following conventional therapies. In the quest for developing more effective cancer therapeutics, the focus has now shifted toward targeting the signaling pathways that govern CSCs behavior. This chapter underscores the significance of these signaling pathways in CSC biology and their potential as pivotal targets for the development of novel chemotherapy approaches. We delve into several key signaling pathways essential for maintaining the defining characteristics of CSCs, including the Wnt, Hedgehog, Notch, JAK-STAT, NF-κB pathways, among others, shedding light on their potential crosstalk. Furthermore, we highlight the latest advancements in CSC-targeted therapies, spanning from promising preclinical models to ongoing clinical trials. A comprehensive understanding of the intricate molecular aspects of CSC signaling pathways and their manipulation holds the prospective to revolutionize cancer treatment paradigms. This, in turn, could lead to more efficacious and personalized therapies with the ultimate goal of eradicating CSCs and enhancing overall patient outcomes. The exploration of CSC signaling pathways represents a key step towards a brighter future in the battle against cancer.

LncRNA FOXD1-AS1 regulates pancreatic cancer stem cell properties and 5-FU resistance by regulating the miR-570-3p/SPP1 axis as a ceRNA

Cancer stem cells (CSCs) play a pivotal role in the pathogenesis of human cancers. Previous studies have highlighted the role of long non-coding RNA (lncRNA) in modulating the stemness of CSCs. In our investigation, we identified an upregulation of lncRNA FOXD1-AS1 in CSCs. The enforced expression of lncRNA FOXD1-AS1 promotes tumorigenesis and self-renewal in pancreatic cancer CSCs. Conversely, the knockdown of lncRNA FOXD1-AS1 inhibits tumorigenesis and self-renewal in pancreatic cancer CSCs. Furthermore, our findings reveal that lncRNA FOXD1-AS1 enhances self-renewal and tumorigenesis in pancreatic cancer CSCs by up-regulating osteopontin/secreted phosphoprotein 1(SPP1) and acting as a ceRNA to sponge miR-570-3p in pancreatic cancer (PC) CSCs. Additionally, lncRNA FOXD1-AS1 depleted pancreatic cancer cells exhibit heightened sensitivity to 5-FU-indued cell growth inhibition and apoptosis. Analysis of patient-derived xenografts (PDX) indicates that a low level of lncRNA FOXD1-AS1 may serve as a predictor of 5-FU benefits in PC patients. Moreover, the introduction of SPP1 can reverse the sensitivity of lncRNA FOXD1-AS1-knockdown PC cells to 5-FU-induced cell apoptosis. Importantly, molecular studies have indicated that the elevated levels of lncRNAFOXD1-AS1 in PC are facilitated through METTL3 and YTHDF1-dependent m6A methylation. In summary, our results underscore the critical functions of lncRNA FOXD1-AS1 in the self-renewal and tumorigenesis of pancreatic cancer CSCs, positioning lncRNA FOXD1-AS1 as a promising therapeutic target for PC.

Cell surface GRP78-directed CAR-T cells are effective at treating human pancreatic cancer in preclinical models

Pancreatic cancer is a highly lethal solid malignancy with limited treatment options. Chimeric antigen receptor T (CAR-T) cell therapy has been successfully applied to treat hematological malignancies, but faces many challenges in solid tumors. One major challenge is the shortage of tumor-selective targets. Cell surface GRP78 (csGRP78) is highly expressed on various solid cancer cells including pancreatic cancer, but not normal cells, providing a potential target for CAR-T cell therapy in pancreatic cancer. Here, we demonstrated that csGRP78-directed CAR-T (GRP78-CAR-T) cells effectively killed the human pancreatic cancer cell lines Bxpc-3-luc, Aspc-1-luc and MIA PaCa-2-luc, and pancreatic cancer stem-like cells derived from Aspc-1-luc cells and MIA PaCa-2-luc cells in vitro by a luciferase-based cytotoxicity assay. Importantly, we showed that GRP78-CAR-T cells efficiently homed to and infiltrated Aspc-1-luc cell-derived xenografts and significantly inhibited pancreatic tumor growth in vivo by performing mouse xenograft experiments. Interestingly, we found that gemcitabine treatment increased csGRP78 expression in gemcitabine-resistant MIA PaCa-2-luc cells, and the coapplication of gemcitabine with GRP78-CAR-T cells led to a robust cytotoxic effect on these cells in vitro. Taken together, our study demonstrates that csGRP78-directed CAR-T cells, alone or in combination with chemotherapy, selectively and efficiently target csGRP78-expressing pancreatic cancer cells to suppress pancreatic tumor growth.

An Update on Gemcitabine-Based Chemosensitization Strategies in Pancreatic Ductal Adenocarcinoma

Pancreatic cancer is the seventh leading cause of cancer-related deaths, and chemotherapy is one of the most important treatments for pancreatic cancer. Unfortunately, pancreatic cancer cells can block chemotherapy drugs from entering the tumor. This is owing to interactions between the tumor's environment and the cancer cells. Here, we review the latest research on the mechanisms by which pancreatic cancer cells block the chemotherapy drug, gemcitabine. The results of our review can help identify potential therapeutic targets for the blocking of gemcitabine by pancreatic cancer cells and may provide new strategies to help chemotherapy drugs penetrate tumors.

Targeting CD24 in Cancer Immunotherapy

Immunotherapy is a hot area in cancer treatment, and one of the keys to this therapy is the identification of the right tumour-associated or tumour-specific antigen. Cluster of differentiation 24 (CD24) is an emerging tumour-associated antigen that is commonly and highly expressed in various tumours. In addition, CD24 is associated with several cancer-related signalling pathways and closely interacts with other molecules and immune cells to influence tumour progression. Monoclonal antibodies, antibody-drug conjugates (ADCs), chimeric antigen receptor (CAR) T-cell therapy, and CAR-NK cell therapy are currently available for the treatment of CD24. In this review, we summarise the existing therapeutic approaches and possible future directions targeting CD24.

Therapeutic Strategies for Pancreatic-Cancer-Related Type 2 Diabetes Centered around Natural Products

Pancreatic ductal adenocarcinoma (PDAC), a highly malignant neoplasm, is classified as one of the most severe and devastating types of cancer. PDAC is a notable malignancy that exhibits a discouraging prognosis and a rising occurrence. The interplay between diabetes and pancreatic cancer exhibits a reciprocal causation. The identified metabolic disorder has been observed to possess noteworthy consequences on health outcomes, resulting in elevated rates of morbidity. The principal mechanisms involve the suppression of the immune system, the activation of pancreatic stellate cells (PSCs), and the onset of systemic metabolic disease caused by dysfunction of the islets. From this point forward, it is important to recognize that pancreatic-cancer-related diabetes (PCRD) has the ability to increase the likelihood of developing pancreatic cancer. This highlights the complex relationship that exists between these two physiological states. Therefore, we investigated into the complex domain of PSCs, elucidating their intricate signaling pathways and the profound influence of chemokines on their behavior and final outcome. In order to surmount the obstacle of drug resistance and eliminate PDAC, researchers have undertaken extensive efforts to explore and cultivate novel natural compounds of the next generation. Additional investigation is necessary in order to comprehensively comprehend the effect of PCRD-mediated apoptosis on the progression and onset of PDAC through the utilization of natural compounds. This study aims to examine the potential anticancer properties of natural compounds in individuals with diabetes who are undergoing chemotherapy, targeted therapy, or immunotherapy. It is anticipated that these compounds will exhibit increased potency and possess enhanced pharmacological benefits. According to our research findings, it is indicated that naturally derived chemical compounds hold potential in the development of PDAC therapies that are both safe and efficacious.

KMT2A associates with PHF5A-PHF14-HMG20A-RAI1 subcomplex in pancreatic cancer stem cells and epigenetically regulates their characteristics

Pancreatic cancer (PC), one of the most aggressive and life-threatening human malignancies, is known for its resistance to cytotoxic therapies. This is increasingly ascribed to the subpopulation of undifferentiated cells, known as pancreatic cancer stem cells (PCSCs), which display greater evolutionary fitness than other tumor cells to evade the cytotoxic effects of chemotherapy. PCSCs are crucial for tumor relapse as they possess 'stem cell-like' features that are characterized by self-renewal and differentiation. However, the molecular mechanisms that maintain the unique characteristics of PCSCs are poorly understood. Here, we identify the histone methyltransferase KMT2A as a physical binding partner of an RNA polymerase-associated PHF5A-PHF14-HMG20A-RAI1 protein subcomplex and an epigenetic regulator of PCSC properties and functions. Targeting the protein subcomplex in PCSCs with a KMT2A-WDR5 inhibitor attenuates their self-renewal capacity, cell viability, and in vivo tumorigenicity.

Role of RNA methylation in the regulation of pancreatic cancer stem cells (Review)

Pancreatic cancer stem cells (CSCs) play a key role in the initiation and progression of pancreatic adenocarcinoma (PDAC). CSCs are responsible for resistance to chemotherapy and radiation, and for cancer metastasis. Recent studies have indicated that RNA methylation, a type of RNA modification, predominantly occurring as m6A methylation, plays an important role in controlling the stemness of cancer cells, therapeutic resistance against chemotherapy and radiation therapy, and their overall relevance to a patient's prognosis. CSCs regulate various behaviors of cancer through cell-cell communication by secreting factors, through their receptors, and through signal transduction. Recent studies have shown that RNA methylation is involved in the biology of the heterogeneity of PDAC. The present review provides an update on the current understanding of RNA modification-based therapeutic targets against deleterious PDAC. Several key pathways and agents that can specifically target CSCs have been identified, thus providing novel insights into the early diagnosis and efficient treatment of PDAC.

Molecular Mechanisms of Tumor Cell Stemness Modulation during Formation of Spheroids

Cancer stem cells (CSCs), their properties and interaction with microenvironment are of interest in modern medicine and biology. There are many studies on the emergence of CSCs and their involvement in tumor pathogenesis. The most important property inherent to CSCs is their stemness. Stemness combines ability of the cell to maintain its pluripotency, give rise to differentiated cells, and interact with environment to maintain a balance between dormancy, proliferation, and regeneration. While adult stem cells exhibit these properties by participating in tissue homeostasis, CSCs behave as their malignant equivalents. High tumor resistance to therapy, ability to differentiate, activate angiogenesis and metastasis arise precisely due to the stemness of CSCs. These cells can be used as a target for therapy of different types of cancer. Laboratory models are needed to study cancer biology and find new therapeutic strategies. A promising direction is three-dimensional tumor models or spheroids. Such models exhibit properties resembling stemness in a natural tumor. By modifying spheroids, it becomes possible to investigate the effect of therapy on CSCs, thus contributing to the development of anti-tumor drug test systems. The review examines the niche of CSCs, the possibility of their study using three-dimensional spheroids, and existing markers for assessing stemness of CSCs.

Tumor Microenvironment Role in Pancreatic Cancer Stem Cells

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with a majority of patients presenting with unresectable or metastatic disease, resulting in a poor 5-year survival rate. This, in turn, is due to a highly complex tumor microenvironment and the presence of cancer stem cells, both of which induce therapy resistance and tumor relapse. Therefore, understanding and targeting the tumor microenvironment and cancer stem cells may be key strategies for designing effective PDAC therapies. In the present review, we summarized recent advances in the role of tumor microenvironment in pancreatic neoplastic progression.

Cancer Stem Cells are Actually Stem Cells with Disordered Differentiation: the Monophyletic Origin of Cancer

Cancer stem cells (CSCs) play an important role in cancer development. Based on advancements in CSC research, we propose a monophyletic model of cancer. This model is based on the idea that CSCs are stem cells with disordered differentiation whose original purpose was to repair damaged tissues. Inflammatory responses and damage repair signals are crucial for the creation and maintenance of CSCs. Normal quiescent stem cells are activated by environmental stimulation, such as an inflammatory response, and undergo cell division and differentiation. In the initial stage of cancer development, stem cell differentiation leads to heteromorphism due to the accumulation of gene mutations, resulting in the development of metaplasia or precancerosis. In the second stage, accumulated mutations induce poor differentiation and lead to cancer development. The monophyletic model illustrates the evolution, biological behavior, and hallmarks of CSCs, proposes a concise understanding of the origin of cancer, and may encourage a novel therapeutic approach.

Cancer Stem Cells in Pancreatic Ductal Adenocarcinoma

The first discovery of cancer stem cells (CSCs) in leukaemia triggered active research on stemness in neoplastic tissues. CSCs represent a subpopulation of malignant cells, defined by unique properties: a dedifferentiated state, self-renewal, pluripotency, an inherent resistance to chemo- and radiotherapy, the presence of certain epigenetic alterations, as well as a higher tumorigenicity in comparison with the general population of cancer cells. A combination of these features highlights CSCs as a high-priority target during cancer treatment. The presence of CSCs has been confirmed in multiple malignancies, including pancreatic ductal adenocarcinoma, an entity that is well known for its dismal prognosis. As the aggressive course of pancreatic carcinoma is partly attributable to treatment resistance, CSCs could contribute to adverse outcomes. The aim of this review is to summarize the current information regarding the markers and molecular features of CSCs in pancreatic ductal adenocarcinoma and the therapeutic options to remove them.

Progress on diagnostic and prognostic markers of pancreatic cancer

Pancreatic cancer is a malignant disease characterized by low survival and high recurrence rate, whose patients are mostly at the stage of locally advanced or metastatic disease when first diagnosed. Early diagnosis is particularly important because prognostic/predictive markers help guide optimal individualized treatment regimens. So far, CA19-9 is the only biomarker for pancreatic cancer approved by the FDA, but its effectiveness is limited by low sensitivity and specificity. With recent advances in genomics, proteomics, metabolomics, and other analytical and sequencing technologies, the rapid acquisition and screening of biomarkers is now possible. Liquid biopsy also occupies a significant place due to its unique advantages. In this review, we systematically describe and evaluate the available biomarkers that have the greatest potential as vital tools in diagnosing and treating pancreatic cancer.

LncRNA model predicts liver cancer drug resistance and validate in vitro experiments

Introduction: Hepatocellular carcinoma (HCC) patients may benefit from chemotherapy, but drug resistance is an important obstacle to favorable prognoses. Overcoming drug resistance is an urgent problem to be solved.

Methods: Differential expression analysis was used to identify long non-coding RNAs (LncRNAs) that differed in chemotherapy-sensitive and chemotherapy-resistant patients. Machine learning algorithms including random forest (RF), lasso regression (LR), and support vector machines (SVMs) were used to identify important chemotherapy-related LncRNAs. A back propagation (BP) network was then used to validate the predictive capacity of important LncRNAs. The molecular functions of hub LncRNAs were investigated via qRT-PCR and cell proliferation assay. Molecular-docking technique was used to explore candidate drug of targets of hub LncRNA in the model.

Results: A total of 125 differentially expressed LncRNAs between sensitive and resistant patients. Seventeen important LncRNAs were identified via RF, and seven factors were identified via LR. With respect to SVM, the top 15 LncRNAs of AvgRank were selected. Five merge chemotherapy-related LncRNAs were used to predict chemotherapy resistance with high accuracy. CAHM was a hub LncRNA of model and expression high in sorafenib resistance cell lines. In addition, the results of CCK8 showed that the sensitivity of HepG2-sorafenib cells to sorafenib was significantly lower than that of HepG2; and the sensitivity of HepG2-sorafenib cells transfected with sh-CAHM was significantly higher than that of Sorafenib. In the non-transfection group, the results of clone formation experiments showed that the number of clones formed by HepG2-sorafenib cells treated with sorafenib was significantly more than that of HepG2; after HepG2-sorafenib cells were transfected with sh-CAHM, the number of clones formed by Sorafenib treatment was significantly higher than that of HepG2 cells. The number was significantly less than that of HepG2-s + sh-NC group. Molecular Docking results indicate that Moschus was candidate drug for target protein of CAHM.

Conclusion: Five chemotherapy-related LncRNAs could predict drug resistance in HCC with high accuracy, and the hub LncRNA CAHM has potential as a new biomarker for HCC chemotherapy resistance.

ITGA5 inhibition in pancreatic stellate cells re-educates the in vitro tumor-stromal crosstalk

The interaction between pancreatic cancer cells (PCCs) and pancreatic stellate cells (PSCs) promotes aggressive progression of pancreatic cancer, and disrupting the tumor-stromal crosstalk is a promising therapeutic strategy. Integrin α5 (ITGA5) is specifically overexpressed in pancreatic cancer stroma and activated PSCs. ITGA5 acts as a mediator in PCCs-PSCs interaction, but its role in regulating biological behaviors of PSCs and PCCs is still not quite clear. In this study, ITGA5 in PSCs was inhibited using its specific inhibitor AV3 peptide or siRNA knockdown technique. Pancreatic cancer SW1990 cells conditioned medium (SW1990-CM) and an indirect co-culture system were used to mimic the environment of the in vitro tumor-stromal crosstalk. Our results showed that ITGA5 inhibition impaired the proliferation and migration of PSCs, but enhanced autophagy. After co-culture with PSCs, SW1990 cells gained some cancer stem cells (CSCs)-like characteristics, such as increased drug resistance, migration and invasion ability, but PSCs with ITGA5 knockdown were incapable of producing these effects. The present results suggested that ITGA5 was involved in the development of the malignant biological behaviors of PSCs and PCCs, and ITGA5 inhibition in PSCs might benefit the treatment of pancreatic cancer by re-educating PCCs-PSCs interaction.

1,2,3,4,6-Penta-O-galloyl-β-D-glucose Inhibits CD44v3, a cancer stem cell marker, by regulating its transcription factor, in human pancreatic cancer cell line

Inhibition of cluster of differentiation 44 (CD44), a pancreatic cancer stem cell (CSC) marker, is a potential treatment for pancreatic ductal adenocarcinoma (PDAC). In this study, we evaluated the effect of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), a gallotannin contained in various medicinal plants, on CD44 standard (CD44s) and CD44 variant 3 (CD44v3) in Mia-PaCa-2, human pancreatic cancer cells and explored the underlying mechanisms. PGG showed cytotoxic effects and inhibited the proliferation of Mia-PaCa-2 cells. It also inhibited clonogenic activity, adhesion to fibronectin, and cell migration, which are characteristics of CSCs. PGG inhibited the expression of CD44s and CD44v3 by inducing the phosphorylation of p53 and suppressing NF-κB and Foxo3. Inhibition of Foxo3 induces CD44v3 ubiquitination. Indeed, PGG increased proteasome activity and promoted CD44v3 ubiquitination. PGG downregulated the CSC regulatory factors Nanog, Oct-4, and Sox-2, which act downstream of CD44v3 signaling. These data indicate that PGG may have therapeutic effects in pancreatic cancer mediated by inhibition of CSC markers.

Natural compounds as a potential modifier of stem cells renewal: Comparative analysis

Cancer stem cells (CSCs) are indispensable for development, progression, drug resistance, and tumor metastasis. Current cancer-directed interventions target targeting rapidly dividing cancer cells and slow dividing CSCs, which are the root cause of cancer origin and recurrence. The most promising targets include several self-renewal pathways involved in the maintenance and renewal of CSCs, such as the Wnt/β-Catenin, Sonic Hedgehog, Notch, Hippo, Autophagy, and Ferroptosis. In view of safety, natural compounds are coming to the front line of treatment modalities for modifying various signaling pathways simultaneously involved in maintaining CSCs. Therefore, targeting CSCs with natural compounds is a promising approach to treating various types of cancers. In view of this, here we provide a comprehensive update on the current status of natural compounds that effectively tune key self-renewal pathways of CSCs. In addition, we highlighted surface expression markers in several types of cancer. We also emphasize how natural compounds target these self-renewal pathways to reduce therapy resistance and cancer recurrence properties of CSCs, hence providing valuable cancer therapeutic strategies. The inclusion of nutraceuticals is believed to enhance the therapeutic efficacy of current cancer-directed interventions significantly.

Cancer stem cells and tumor heterogeneity: Deciphering the role in tumor progression and metastasis

Tumor heterogeneity, in principle, reflects the variation among different cancer cell populations. It can be termed inter- or intra-tumoral heterogeneity, respectively, based on its occurrence in various tissues from diverse patients or within a single tumor. The intra-tumoral heterogeneity is one of the leading causes of cancer progression and treatment failure, with the cancer stem cells (CSCs) contributing immensely to the same. These niche cells, similar to normal stem cells, possess the characteristics of self-renewal and differentiation into multiple cell types. Moreover, CSCs contribute to tumor growth and surveillance by promoting recurrence, metastasis, and therapeutic resistance. Diverse factors, including intracellular signalling pathways and tumor microenvironment (TME), play a vital role in regulating these CSCs. Although a panel of markers is considered to identify the CSC pool in various cancers, further research is needed to discriminate cancer-specific CSC markers in those. CSCs have also been found to be promising therapeutic targets for cancer therapy. Several small molecules, natural compounds, antibodies, chimeric antigen receptor T (CAR-T) cells, and CAR-natural killer (CAR-NK) cells have emerged as therapeutic tools for specific targeting of CSCs. Interestingly, many of these are in clinical trials too. Despite being a much-explored avenue of research for years, and we have come to understand its nitty-gritty, there is still a tremendous gap in our knowledge concerning its precise genesis and regulation. Hence, a concrete understanding is needed to assess the CSC-TME link and how to target different cancer-specific CSCs by designing newer tools. In this review, we have summarized CSC, its causative, different pathways and factors regulating its growth, association with tumor heterogeneity, and last but not least, discussed many of the promising CSC-targeted therapies for combating cancer metastasis.

Cancer Stem Cells: From an Insight into the Basics to Recent Advances and Therapeutic Targeting

Cancer is characterized by an abnormal growth of the cells in an uncontrolled manner. These cells have the potential to invade and can eventually turn into malignancy, leading to highly fatal forms of tumor. Small subpopulations of cancer cells that are long-lived with the potential of excessive self-renewal and tumor formation are called cancer stem cells (CSCs) or cancer-initiating cells or tumor stem cells. CSCs can be found in tissues, such as breast, brain, lung, liver, ovary, and testis; however, their origin is still a matter of debate. These cells can differentiate and possess self-renewal capacity maintained by numerous intracellular signal transduction pathways, such as the Wnt/β-catenin signaling, Notch signaling, transforming growth factor-β signaling, and Hedgehog signaling. They can also contribute to numerous malignancies and are an important reason for tumor recurrence and metastasis because they are resistant to the known therapeutic strategies that mainly target the bulk of the tumor cells. This review contains collected and compiled information after analyzing published works of the last three decades. The goal was to gather information of recent breakthroughs related to CSCs, strategies to target CSCs' niche (e.g., nanotechnology with tumor biology), and their signaling pathways for cancer therapy. Moreover, the role of metformin, an antidiabetic drug, acting as a chemotherapeutic agent on CSCs by inhibiting cellular transformation and its selective killing is also addressed.

Epithelial and Mesenchymal Features of Pancreatic Ductal Adenocarcinoma Cell Lines in Two- and Three-Dimensional Cultures

Pancreatic ductal adenocarcinoma (PDAC) is an intractable cancer that is difficult to diagnose early, and there is no cure other than surgery. PDAC is classified as an adenocarcinoma that has limited effective anticancer drug and molecular-targeted therapies compared to adenocarcinoma found in other organs. A large number of cancer cell lines have been established from patients with PDAC that have different genetic abnormalities, including four driver genes; however, little is known about the differences in biological behaviors among these cell lines. Recent studies have shown that PDAC cell lines can be divided into epithelial and mesenchymal cell lines. In 3D cultures, morphological and functional differences between epithelial and mesenchymal PDAC cell lines were observed as well as the drug effects of different anticancer drugs. These effects included gemcitabine causing an increased growth inhibition of epithelial PDAC cells, while nab-paclitaxel caused greater mesenchymal PDAC cell inhibition. Thus, examining the characteristics of epithelial or mesenchymal PDAC cells with stromal cells using a 3D co-culture may lead to the development of new anticancer drugs.

Gp130-Mediated STAT3 Activation Contributes to the Aggressiveness of Pancreatic Cancer through H19 Long Non-Coding RNA Expression

Simple Summary

The signal transducer and activator of transcription 3 (STAT3) activation correlate with the aggressiveness of pancreatic ductal adenocarcinoma (PDAC). We demonstrated that the autocrine/paracrine interleukin-6 (IL-6) or leukemia inhibitory factor (LIF)/glycoprotein 130 (gp130)/STAT3 pathway contributes to the maintenance of stemness features and membrane-type 1 matrix metalloproteinase (MT1-MMP) expression, and modulates transforming growth factor (TGF)-β1/Smad signaling-mediated epithelial-mesenchymal transition (EMT) and invasion through regulation of TGFβ-RII expression in PDAC cancer stem cell (CSC)-like cells. Furthermore, we demonstrated that p-STAT3 acts through the IL-6 or LIF/gp130/STAT3 pathway to access the active promoter region of metastasis-related long non-coding RNA H19 and contribute to its transcription in CSC-like cells. Therefore, the autocrine/paracrine IL-6 or LIF/gp130/STAT3 pathway in PDAC CSC-like cells exhibiting H19 expression is considered to be involved in the aggressiveness of PDAC, and inhibition of the gp130/STAT3 pathway is a promising strategy to target CSCs for the elimination of PDAC (146/150).

Abstract

Signaling pathways involving signal transducer and activator of transcription 3 (STAT3) play key roles in the aggressiveness of pancreatic ductal adenocarcinoma (PDAC), including their tumorigenesis, invasion, and metastasis. Cancer stem cells (CSCs) have been correlated with PDAC aggressiveness, and activation of STAT3 is involved in the regulation of CSC properties. Here, we investigated the involvement of interleukin-6 (IL-6) or the leukemia inhibitory factor (LIF)/glycoprotein 130 (gp130)/STAT3 pathway and their role in pancreatic CSCs. In PDAC CSC-like cells formed by culturing on a low attachment plate, autocrine/paracrine IL-6 or LIF contributes to gp130/STAT3 pathway activation. Using a gp130 inhibitor, we determined that the gp130/STAT3 pathway contributes to the maintenance of stemness features, the expression of membrane-type 1 matrix metalloproteinase (MT1-MMP), and the invasion of PDAC CSC-like cells. The gp130/STAT3 pathway also modulates the transforming growth factor (TGF)-β1/Smad pathway required for epithelial-mesenchymal transition induction through regulation of TGFβ-RII expression in PDAC CSC-like cells. Furthermore, chromatin immunoprecipitation assays revealed that p-STAT3 can access the active promoter region of H19 to influence this metastasis-related long non-coding RNA and contribute to its transcription in PDAC CSC-like cells. Therefore, the autocrine/paracrine IL-6 or LIF/gp130/STAT3 pathway in PDAC CSC-like cells may eventually facilitate invasion and metastasis, two hallmarks of malignancy. We propose that inhibition of the gp130/STAT3 pathway provides a promising strategy for targeting CSCs for the treatment of PDAC.

Abnormal Glycosylation in Cancer Cells and Cancer Stem Cells as a Therapeutic Target

Tumor resistance and recurrence have been associated with the presence of cancer stem cells (CSCs) in tumors. The functions and survival of the CSCs have been associated with several intracellular and extracellular features. Particularly, the abnormal glycosylation of these signaling pathways and markers of CSCs have been correlated with maintaining survival, self-renewal and extravasation properties. Here, we highlight the importance of glycosylation in promoting the stemness character of CSCs and the current strategies for targeting abnormal glycosylation toward generating effective therapies against the CSC population.

Upregulation of miR-216a-5p by Lentinan Targeted Inhibition of JAK2/STAT3 Signaling Pathway to Reduce Lung Adenocarcinoma Cell Stemness, Promote Apoptosis, and Slow Down the Lung Adenocarcinoma Mechanisms

To investigate the effect of Lentinan (LNT) on lung adenocarcinoma (LUAD) cell stemness and its mechanism. In this study, we founded that LNT significantly reduce the cell proliferation, activity, migration, invasion, and stemness of LUAD cells, and promote their apoptosis compared with the control group in vitro. Moreover, LNT significantly inhibited the volume and weight of tumors of nude mice in vivo. At the same time, LNT can significantly up-regulate miR-216a-5p levels and reduce the protein expression of phospho-JAK2 (Y1007/1008) and phospho-STAT3 (Tyr705), thereby inhibiting the JAK2/STAT3 signaling pathway. Interfering with miR-216a-5p expression and activating the JAK2/STAT3 signaling pathway can significantly reverse LNT inhibitory effects on LUAD. Collectively, LNT can inhibit the JAK2/STAT3 signaling pathway by up-regulating miR-216a-5p, reducing stemness, and promoting LUAD cells apoptosis, then slow down LUAD occurrence and development, providing concepts and experimental foundation treating patients with LUAD.

Repurposing of Anticancer Stem Cell Drugs in Brain Tumors

Brain tumors in adults may be infrequent when compared with other cancer etiologies, but they remain one of the deadliest with bleak survival rates. Current treatment modalities encompass surgical resection, chemotherapy, and radiotherapy. However, increasing resistance rates are being witnessed, and this has been attributed, in part, to cancer stem cells (CSCs). CSCs are a subpopulation of cancer cells that reside within the tumor bulk and have the capacity for self-renewal and can differentiate and proliferate into multiple cell lineages. Studying those CSCs enables an increasing understanding of carcinogenesis, and targeting CSCs may overcome existing treatment resistance. One approach to weaponize new drugs is to target these CSCs through drug repurposing which entails using drugs, which are Food and Drug Administration-approved and safe for one defined disease, for a new indication. This approach serves to save both time and money that would otherwise be spent in designing a totally new therapy. In this review, we will illustrate drug repurposing strategies that have been used in brain tumors and then further elaborate on how these approaches, specifically those that target the resident CSCs, can help take the field of drug repurposing to a new level.

GLRX3, a novel cancer stem cell-related secretory biomarker of pancreatic ductal adenocarcinoma

BACKGROUND

Cancer stem cells (CSCs) are implicated in carcinogenesis, cancer progression, and recurrence. Several biomarkers have been described for pancreatic ductal adenocarcinoma (PDAC) CSCs; however, their function and mechanism remain unclear.

METHOD

In this study, secretome analysis was performed in pancreatic CSC-enriched spheres and control adherent cells for biomarker discovery. Glutaredoxin3 (GLRX3), a novel candidate upregulated in spheres, was evaluated for its function and clinical implication.

RESULTS

PDAC CSC populations, cell lines, patient tissues, and blood samples demonstrated GLRX3 overexpression. In contrast, GLRX3 silencing decreased the in vitro proliferation, migration, clonogenicity, and sphere formation of cells. GLRX3 knockdown also reduced tumor formation and growth in vivo. GLRX3 was found to regulate Met/PI3K/AKT signaling and stemness-related molecules. ELISA results indicated GLRX3 overexpression in the serum of patients with PDAC compared to that in healthy controls. The sensitivity and specificity of GLRX3 for PDAC diagnosis were 80.0 and 100%, respectively. When GLRX3 and CA19-9 were combined, sensitivity was significantly increased to 98.3% compared to that with GLRX3 or CA19-9 alone. High GLRX3 expression was also associated with poor disease-free survival in patients receiving curative surgery.

CONCLUSION

Overall, these results indicate GLRX3 as a novel diagnostic marker and therapeutic target for PDAC targeting CSCs.

Activation of a Ductal-to-Endocrine Transdifferentiation Transcriptional Program in the Pancreatic Cancer Cell Line PANC-1 Is Controlled by RAC1 and RAC1b through Antagonistic Regulation of Stemness Factors

Simple Summary

For patients with metastatic pancreatic ductal adenocarcinoma (PDAC) there is currently no cure; hence, novel effective therapies are desperately needed. Among PDAC patients, the tumor cell phenotypes are heterogeneous as a result of epithelial–mesenchymal transition, a process that endows them with the ability to metastasize, resist therapy, and generate cancer stem cells. The heightened plasticity of quasimesenchymal and potentially metastatic tumor cells may, however, also be exploited for their transdifferentiation into benign, highly differentiated or post-mitotic cells. Since PDAC patients often have a need for replacement of insulin-producing cells, conversion of tumor cells with a ductal/exocrine origin to endocrine β cell-like cells is an attractive therapeutic option. Successful transdifferentiation into insulin-producing cells has been reported for the quasimesenchymal cell line PANC-1; however, the mechanistic basis of this transformation process is unknown. Here, we show that the small GTPases, RAC1 and RAC1b control this process by antagonistic regulation of stemness genes.

Abstract

Epithelial–mesenchymal transition (EMT) is a driving force for tumor growth, metastatic spread, therapy resistance, and the generation of cancer stem cells (CSCs). However, the regained stem cell character may also be exploited for therapeutic conversion of aggressive tumor cells to benign, highly differentiated cells. The PDAC-derived quasimesenchymal-type cell lines PANC-1 and MIA PaCa-2 have been successfully transdifferentiated to endocrine precursors or insulin-producing cells; however, the underlying mechanism of this increased plasticity remains elusive. Given its crucial role in normal pancreatic endocrine development and tumor progression, both of which involve EMT, we analyzed here the role of the small GTPase RAC1. Ectopic expression in PANC-1 cells of dominant negative or constitutively active mutants of RAC1 activation blocked or enhanced, respectively, the cytokine-induced activation of a ductal-to-endocrine transdifferentiation transcriptional program (deTDtP) as revealed by induction of the NEUROG3, INS, SLC2A2, and MAFA genes. Conversely, ectopic expression of RAC1b, a RAC1 splice isoform and functional antagonist of RAC1-driven EMT, decreased the deTDtP, while genetic knockout of RAC1b dramatically increased it. We further show that inhibition of RAC1 activation attenuated pluripotency marker expression and self-renewal ability, while depletion of RAC1b dramatically enhanced stemness features and clonogenic potential. Finally, rescue experiments involving pharmacological or RNA interference-mediated inhibition of RAC1 or RAC1b, respectively, confirmed that both RAC1 isoforms control the deTDtP in an opposite manner. We conclude that RAC1 and RAC1b antagonistically control growth factor-induced activation of an endocrine transcriptional program and the generation of CSCs in quasimesenchymal PDAC cells. Our results have clinical implications for PDAC patients, who in addition to eradication of tumor cells have a need for replacement of insulin-producing cells.

Extracellular vesicles in pancreatic cancer progression and therapies

Pancreatic cancer (PC) is one of the leading causes of cancer-related death worldwide due to delayed diagnosis and limited treatments. More than 90% of all pancreatic cancers are pancreatic ductal adenocarcinoma (PDAC). Extensive communication between tumour cells and other cell types in the tumour microenvironment have been identified which regulate cancer hallmarks during pancreatic tumorigenesis via secretory factors and extracellular vesicles (EVs). The EV-capsuled factors not only facilitate tumour growth locally, but also enter circulation and reach distant organs to construct a pre-metastatic niche. In this review, we delineate the key factors in pancreatic ductal adenocarcinoma derived EVs that mediate different tumour processes. Also, we highlight the factors that are related to the crosstalk with cancer stem cells/cancer-initiating cells (CSC/CIC), the subpopulation of cancer cells that can efficiently metastasize and resist currently used chemotherapies. Lastly, we discuss the potential of EV-capsuled factors in early diagnosis and antitumour therapeutic strategies.

Engineering of a functional pancreatic acinus with reprogrammed cancer cells by induced PTF1a expression

A pancreatic acinus is a functional unit of the exocrine pancreas producing digest enzymes. Its pathobiology is crucial to pancreatic diseases including pancreatitis and pancreatic cancer, which can initiate from pancreatic acini. However, research on pancreatic acini has been significantly hampered due to the difficulty of culturing normal acinar cells in vitro. In this study, an in vitro model of the normal acinus, named pancreatic acinus-on-chip (PAC), is developed using reprogrammed pancreatic cancer cells. The developed model is a microfluidic platform with an epithelial duct and acinar sac geometry microfabricated by a newly developed two-step controlled "viscous-fingering" technique. In this model, human pancreatic cancer cells, Panc-1, reprogrammed to revert to the normal state upon induction of PTF1a gene expression, are cultured. Bioinformatic analyses suggest that, upon induced PTF1a expression, Panc-1 cells transition into a more normal and differentiated acinar phenotype. The microanatomy and exocrine functions of the model are characterized to confirm the normal acinus phenotypes. The developed model provides a new and reliable testbed to study the initiation and progression of pancreatic cancers.

Cancer Stem Cell for Tumor Therapy

Simple Summary

Although many methods have been applied in clinical treatment for tumors, they still always show a poor prognosis. Molecule targeted therapy has revolutionized tumor therapy, and a proper target must be found urgently. With a crucial role in tumor development, metastasis and recurrence, cancer stem cells have been found to be a feasible and potential target for tumor therapy. We list the unique biological characteristics of cancer stem cells and summarize the recent strategies to target cancer stem cells for tumor therapy, through which we hope to provide a comprehensive understanding of cancer stem cells and find a better combinational strategy to target cancer stem cells for tumor therapy.

Abstract

Tumors pose a significant threat to human health. Although many methods, such as operations, chemotherapy and radiotherapy, have been proposed to eliminate tumor cells, the results are unsatisfactory. Targeting therapy has shown potential due to its specificity and efficiency. Meanwhile, it has been revealed that cancer stem cells (CSCs) play a crucial role in the genesis, development, metastasis and recurrence of tumors. Thus, it is feasible to inhibit tumors and improve prognosis via targeting CSCs. In this review, we provide a comprehensive understanding of the biological characteristics of CSCs, including mitotic pattern, metabolic phenotype, therapeutic resistance and related mechanisms. Finally, we summarize CSCs targeted strategies, including targeting CSCs surface markers, targeting CSCs related signal pathways, targeting CSC niches, targeting CSC metabolic pathways, inducing differentiation therapy and immunotherapy (tumor vaccine, CAR-T, oncolytic virus, targeting CSCs–immune cell crosstalk and immunity checkpoint inhibitor). We highlight the potential of immunity therapy and its combinational anti-CSC therapies, which are composed of different drugs working in different mechanisms.

Identification and Prognostic Value Exploration of Radiotherapy Sensitivity-Associated Genes in Non-Small-Cell Lung Cancer

Background

Non-small-cell lung cancer (NSCLC) is a prevalent malignancy with high mortality and poor prognosis. The radiotherapy is one of the most common treatments of NSCLC, and the radiotherapy sensitivity of patients could affect the individual prognosis of NSCLC. However, the prognostic signatures related to radiotherapy response still remain limited. Here, we explored the radiosensitivity-associated genes and constructed the prognostically predictive model of NSCLC cases.

Methods

The NSCLC samples with radiotherapy records were obtained from The Cancer Genome Atlas database, and the mRNA expression profiles of NSCLC patients from the GSE30219 and GSE31210 datasets were obtained from the Gene Expression Omnibus database. The Weighted Gene Coexpression Network Analysis (WGCNA), univariate, least absolute shrinkage and selection operator (LASSO), multivariate Cox regression analysis, and nomogram were conducted to identify and validate the radiotherapy sensitivity-related signature.

Results

WGCNA revealed that 365 genes were significantly correlated with radiotherapy response. LASSO Cox regression analysis identified 8 genes, including FOLR3, SLC6A11, ALPP, IGFN1, KCNJ12, RPS4XP22, HIST1H2BH, and BLACAT1. The overall survival (OS) of the low-risk group was better than that of the high-risk group separated by the Risk Score based on these 8 genes for the NSCLC patients. Furthermore, the immune infiltration analysis showed that monocytes and activated memory CD4 T cells had different relative proportions in the low-risk group compared with the high-risk group. The Risk Score was correlated with immune checkpoints, including CTLA4, PDL1, LAG3, and TIGIT.

Conclusion

We identified 365 genes potentially correlated with the radiotherapy response of NSCLC patients. The Risk Score model based on the identified 8 genes can predict the prognosis of NSCLC patients.

The plasticity of pancreatic cancer stem cells: implications in therapeutic resistance

The ever-growing perception of cancer stem cells (CSCs) as a plastic state rather than a hardwired defined entity has evolved our understanding of the functional and biological plasticity of these elusive components in malignancies. Pancreatic cancer (PC), based on its biological features and clinical evolution, is a prototypical example of a CSC-driven disease. Since the discovery of pancreatic CSCs (PCSCs) in 2007, evidence has unraveled their control over many facets of the natural history of PC, including primary tumor growth, metastatic progression, disease recurrence, and acquired drug resistance. Consequently, the current near-ubiquitous treatment regimens for PC using aggressive cytotoxic agents, aimed at ''tumor debulking'' rather than eradication of CSCs, have proven ineffective in providing clinically convincing improvements in patients with this dreadful disease. Herein, we review the key hallmarks as well as the intrinsic and extrinsic resistance mechanisms of CSCs that mediate treatment failure in PC and enlist the potential CSC-targeting 'natural agents' that are gaining popularity in recent years. A better understanding of the molecular and functional landscape of PCSC-intrinsic evasion of chemotherapeutic drugs offers a facile opportunity for treating PC, an intractable cancer with a grim prognosis and in dire need of effective therapeutic advances.

Roles of voltage‑gated potassium channels in the maintenance of pancreatic cancer stem cells

The targeting of membrane proteins that are activated in cancer stem cells (CSCs) represents one of the key recent strategies in cancer therapy. The present study analyzed ion channel expression profiles and functions in pancreatic CSCs (PCSCs). Cells strongly expressing aldehyde dehydrogenase 1 family member A1 (ALDH1A1) were isolated from the human pancreatic PK59 cell line using fluorescence-activated cell sorting, and PCSCs were identified based on tumorsphere formation. Microarray analysis was performed to investigate the gene expression profiles in PCSCs. ALDH1A1 messenger RNA levels were higher in PCSCs compared with non-PCSCs. PCSCs were resistant to 5-fluorouracil and capable of redifferentiation. The results of the microarray analysis revealed that gene expression related to ion channels, including voltage-gated potassium channels (Kv), was upregulated in PCSCs compared with non-PCSCs. 4-Aminopyridine (4-AP), a potent Kv inhibitor, exhibited greater cytotoxicity in PCSCs compared with non-PCSCs. In a xenograft model in nude mice, tumor volumes were significantly lower in mice inoculated with PK59 cells pre-treated with 4-AP compared with those in mice injected with non-treated cells. The present results identified a role of Kv in the persistence of PCSCs and suggested that the Kv inhibitor 4-AP may have potential as a therapeutic agent for pancreatic carcinoma.