Cancer stem cells: Regulation programs, immunological properties and immunotherapy

Stem Cells in Cancer: From Mechanisms to Therapeutic Strategies

Stem cells have emerged as a pivotal area of research in the field of oncology, offering new insights into the mechanisms of cancer initiation, progression, and resistance to therapy. This review provides a comprehensive overview of the role of stem cells in cancer, focusing on cancer stem cells (CSCs), their characteristics, and their implications for cancer therapy. We discuss the origin and identification of CSCs, their role in tumorigenesis, metastasis, and drug resistance, and the potential therapeutic strategies targeting CSCs. Additionally, we explore the use of normal stem cells in cancer therapy, focusing on their role in tissue regeneration and their use as delivery vehicles for anticancer agents. Finally, we highlight the challenges and future directions in stem cell research in cancer.

Phase separation of EEF1E1 promotes tumor stemness via PTEN/AKT-mediated DNA repair in hepatocellular carcinoma

This study aimed to investigate the associations of liquid-liquid phase separation (LLPS) and tumor stemness in hepatocellular carcinomas (HCC). LLPS-related genes were extracted from DrLLPS, LLPSDB and PhaSepDB databases. Stemness index (mRNAsi) was calculated based on the data from TCGA and Progenitor Cell Biology Consortium. Through some series of bioinformatics methods, we first found that stemness index mRNAsi was associated with worse survival outcomes, immune infiltration and therapy sensitivity in HCC. G2M checkpoint and DNA repair pathways were significantly activated with high mRNAsi. Totally, 71 differentially expressed LLPS genes in HCC were correlated with mRNAsi, and a mRNAsi-associated LLPS gene signature (KPNA2, EEF1E1 and ATIC) was identified to predict prognosis for HCC patients. mRNAsi-associated LLPS genes contributed to cluster HCC patients into four molecular clusters that markedly differed on survival, immune infiltration and therapy sensitivity. Further in vivo and in vitro experiments showed that EEF1E1 was highly expressed in HepG2 and HCCLM3 cells, and EEF1E1 silencing observably inhibited tumor cell growth, liver cancer stem cells (CSCs) markers (CD133, EpCAM and SOX2) expression, enhanced DNA damage marker γH2AX expression by activating PTEN/AKT pathway. EEF1E1 could undergo LLPS condensates, and roles of EEF1E1 on tumor cells were partly reversed after inhibiting LLPS using 1, 6-hexanediol. In conclusion, EEF1E1 was identified as a phase separation protein and involves in tumor stemness and DNA damage repair in HCC. EEF1E1 and its LLPS condensate may be novel targets to elaborate the underlying mechanisms of CSCs propagation in HCC.

Identification of a Cancer Stem Cell-Related Gene Signature in Hepatocellular Carcinoma Based on Single-Cell RNA-Seq and Bulk RNA-Seq Analysis

Cancer stem cells (CSCs) are a heterogeneous group of tumor cells that play a significant role in tumorigenesis, therapeutic resistance, and recurrence in liver hepatocellular carcinoma (LIHC). This study combines clinical data sets from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC) with bulk RNA sequencing data. This study also features the GSE156625 single-cell RNA sequencing (scRNA) data set from the GEO to explore the prognostic significance of CSC biomarkers (BCSCs) in LIHC. In this research, we introduce a developed prognostic risk model that relies on nine specific BCSCs, including ADM, CCL5, CD274, DLGAP5, HOXD9, IGF1, S100A9, SOCS2, and TNFRSF11B. It was found that high-risk patients experience shorter overall survival rates when compared to low-risk patients. Additionally, the study characterized the composition of immune cells within the tumor microenvironment (TME) and revealed significant variations in gene-expression levels and mutation rates between different risk groups. The model suggests that liver cancer progression might be driven by immune evasion independent of PD-L1 and highlights the potential of the low-risk BCSC group being sensitive to various treatments. Our findings offer a promising foundation for personalized LIHC therapy and highlight the need for further experimental validation of the roles of these CSCs in disease progression.

Comprehensive Analysis and Verification of the Prognostic Significance of Cuproptosis-Related Genes in Colon Adenocarcinoma

Colon adenocarcinoma (COAD) is a frequently occurring and lethal cancer. Cuproptosis is an emerging type of cell death, and the underlying pathways involved in this process in COAD remain poorly understood. Transcriptomic and clinical data for COAD patients were collected from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. We investigated alterations in DNA and chromatin of cuproptosis-related genes (CRGs) in COAD. In order to identify predictive differentially expressed genes (DEGs) and various molecular subtypes, we used consensus cluster analysis. Through univariate, multivariate, and Lasso Cox regression analyses, four CRGs were identified. A risk prognostic model for cuproptosis characteristics was constructed based on four CRGs. This study also examined the association between the risk score and the tumor microenvironment (TME), the immune landscape, and drug sensitivity. We distinguished two unique molecular subtypes using consensus clustering analysis. We discovered that the clinical characteristics, prognosis, and TME cell infiltration characteristics of patients with multilayer CRG subtypes were all connected. The internal and external evaluations of the predicted accuracy of the prognostic model built using data derived from a cuproptosis risk score were completed at the same time. A nomogram and a clinical pathological analysis make it more useful in the field of medicine. A significant rise in immunosuppressive cells was observed in the high cuproptosis risk score group, with a correlation identified between the cuproptosis risk score and immune cell infiltration. Despite generally poor prognoses, the patients with a high cuproptosis risk but low tumor mutation burden (TMB), cancer stem cell (CSC) index, or microsatellite instability (MSI) may still benefit from immunotherapy. Furthermore, the cuproptosis risk score positively correlated with immune checkpoint gene expression. Analyzing the potential sensitivity to medications could aid in the development of clinical chemotherapy regimens and decision-making. CRGs are the subject of our in-depth study, which exposed an array of regulatory mechanisms impacting TME. In addition, we performed additional data mining into clinical features, prognosis effectiveness, and possible treatment medications. COAD's molecular pathways will be better understood, leading to more precise treatment options.

In vitro induction of anti‑lung cancer immune response by the A549 lung cancer stem cell lysate‑sensitized dendritic cell vaccine

Lung adenocarcinoma is one of the most fatal types of cancer worldwide, with non-small cell lung cancer being the most common subtype. Therefore, there is need for improved treatment approaches. Tumor growth results from the proliferation of a very small number of tumor stem cells, giving rise to the theory of cancer stem cells (CSCs). Lung CSCs are associated with lung cancer development, and although chemotherapy drugs can inhibit the proliferation of lung cancer cells, they have difficulty acting on lung CSCs. Even if the tumor appears to have disappeared after chemotherapy, the presence of a small number of residual tumor stem cells can lead to cancer recurrence and metastasis. Hence, targeting and eliminating lung CSCs is of significant therapeutic importance. In this study, we cultured A549 cells in sphere-forming conditions using B27, EGF, and bFGF, isolated peripheral blood mononuclear cells (PBMCs), and induced and characterized dendritic cells (DCs). We also isolated and expanded T lymphocytes. DC vaccines were prepared using A549 stem cell lysate or A549 cell lysate for sensitization and compared with non-sensitized DC vaccines. The content of IFN-γ in the supernatant of cultures with vaccines and T cells was measured by ELISA. The cytotoxic effects of the vaccines on A549 cells and stem cells were assessed using the Cytotox96 assay, and the impact of the vaccines on A549 cell migration and apoptosis was evaluated using Transwell assays and flow cytometry. DC vaccines sensitized with human lung CSC lysates induced significant in vitro cytotoxic effects on A549 lung cancer cells and CSCs by T lymphocytes, while not producing immune cytotoxic effects on human airway epithelial cells. Moreover, the immune-killing effect induced by DC vaccines sensitized with lung CSC lysates was superior to that of DC vaccines sensitized with lung cancer cells.

Comprehensive Characterization of the Integrin Family Across 32 Cancer Types

Integrin genes are widely involved in tumorigenesis. Yet, a comprehensive characterization of integrin family members and their interactome at the pan-cancer level is lacking. Here, we systematically analyzed integrin family in approximately 10,000 tumors across 32 cancer types. Globally, integrins represent a frequently altered and misexpressed pathway, with alteration and dysregulation overall being protumorigenic. Expression dysregulation, better than mutational landscape, of integrin family successfully identifies a subgroup of aggressive tumors with a high level of proliferation and stemness. The results reveal that several molecular mechanisms collectively regulate integrin expression in a context-dependent manner. For potential clinical usage, we constructed a weighted scoring system, integrinScore, to measure integrin signaling patterns in individual tumors. Remarkably, integrinScore was consistently correlated with predefined molecular subtypes in multiple cancers, with integrinScore-high tumors being more aggressive. Importantly, integrinScore was cancer-dependent and closely associated with proliferation, stemness, tumor microenvironment, metastasis, and immune signatures. IntegrinScore also predicted patients' response to immunotherapy. By mining drug databases, we unraveled an array of compounds that may modulate integrin signaling. Finally, we built a user-friendly database, Pan-cancer Integrin Explorer (PIExplorer; http://computationalbiology.cn/PIExplorer), to facilitate researchers to explore integrin-related knowledge. Collectively, we provide a comprehensive characterization of integrins across cancers and offer gene-specific and cancer-specific rationales for developing integrin-targeted therapy.

Cancer Stemness Online: A Resource for Investigating Cancer Stemness and Associations with Immune Response

Cancer progression involves the gradual loss of a differentiated phenotype and the acquisition of progenitor and stem cell-like features, which are potential culprits of immunotherapy resistance. Although the state-of-the-art predictive computational methods have facilitated the prediction of cancer stemness, there remains a lack of efficient resources to accommodate various usage requirements. Here, we present the Cancer Stemness Online, an integrated resource for efficiently scoring cancer stemness potential at both bulk and single-cell levels. This resource integrates eight robust predictive algorithms as well as 27 signature gene sets associated with cancer stemness for predicting stemness scores. Downstream analyses were performed from five distinct aspects: identifying the signature genes of cancer stemness; exploring the associations with cancer hallmarks and cellular states; exploring the associations with immune response and the communications with immune cells; investigating the contributions to patient survival; and performing a robustness analysis of cancer stemness among different methods. Moreover, the pre-calculated cancer stemness atlas for more than 40 cancer types can be accessed by users. Both the tables and diverse visualizations of the analytical results are available for download. Together, Cancer Stemness Online is a powerful resource for scoring cancer stemness and expanding downstream functional interpretation, including immune response and cancer hallmarks. Cancer Stemness Online is freely accessible at http://bio-bigdata.hrbmu.edu.cn/CancerStemnessOnline.

Inhibition of PRMT5 moderately suppresses prostate cancer growth in vivo but enhances its response to immunotherapy

Protein arginine methylation is a common post-translational modification (PTM) catalyzed by nine protein arginine methyltransferases (PRMTs). As the major symmetric arginine methyltransferase that methylates both histone and non-histone substrates, PRMT5 plays key roles in a number of biological processes critical for development and tumorigenesis. PRMT5 overexpression has been reported in multiple cancer types including prostate cancer (PCa), but the exact biological and mechanistic understanding of PRMT5 in aggressive PCa remains ill-defined. Here, we show that PRMT5 is upregulated in PCa, correlates with worse patient survival, promotes corrupted RNA splicing, and functionally cooperates with an array of pro-tumorigenic pathways to enhance oncogenesis. PRMT5 inhibition via either genetic knockdown or pharmacological inhibition reduces stemness with paralleled differentiation and arrests cell cycle progression without causing appreciable apoptosis. Strikingly, the severity of antitumor effect of PRMT5 inhibition correlates with disease aggressiveness, with AR+ PCa being less affected. Molecular characterization pinpoints MYC, but not (or at least to a lesser degree) AR, as the main partner of PRMT5 to form a positive feedback loop to exacerbate malignancy in both AR+ and AR- PCa cells. Inspired by the surprising finding that PRMT5 negatively correlates with tumor immune infiltration and transcriptionally suppresses an immune-gene program, we further show that although PRMT5 inhibitor (PRMT5i) EPZ015666 or anti-PD-1 immunotherapy alone exhibits limited antitumor effects, combination of PRMT5i with anti-PD-1 displays superior efficacy in inhibiting castration-resistant PCa (CRPC) in vivo. Finally, to expand the potential use of PRMT5i through a synthetic lethality concept, we also perform a global CRISPR/Cas9 knockout screen to unravel that many clinical-grade drugs of known oncogenic pathways can be repurposed to target CRPC when used in combination with PRMT5i at low doses. Collectively, our findings establish a rationale to exploit PRMT5i in combination with immunotherapy or other targeted therapies to treat aggressive PCa.

Unveiling the Dynamic Interplay between Cancer Stem Cells and the Tumor Microenvironment in Melanoma: Implications for Novel Therapeutic Strategies

Cutaneous melanoma still represents a significant health burden worldwide, being responsible for the majority of skin cancer deaths. Key advances in therapeutic strategies have significantly improved patient outcomes; however, most patients experience drug resistance and tumor relapse. Cancer stem cells (CSCs) are a small subpopulation of cells in different tumors, including melanoma, endowed with distinctive capacities of self-renewal and differentiation into bulk tumor cells. Melanoma CSCs are characterized by the expression of specific biomarkers and intracellular pathways; moreover, they play a pivotal role in tumor onset, progression and drug resistance. In recent years, great efforts have been made to dissect the molecular mechanisms underlying the protumor activities of melanoma CSCs to provide the basis for novel CSC-targeted therapies. Herein, we highlight the intricate crosstalk between melanoma CSCs and bystander cells in the tumor microenvironment (TME), including immune cells, endothelial cells and cancer-associated fibroblasts (CAFs), and its role in melanoma progression. Specifically, we discuss the peculiar capacities of melanoma CSCs to escape the host immune surveillance, to recruit immunosuppressive cells and to educate immune cells toward an immunosuppressive and protumor phenotype. We also address currently investigated CSC-targeted strategies that could pave the way for new promising therapeutic approaches for melanoma care.

Cancer-associated fibroblasts and prostate cancer stem cells: crosstalk mechanisms and implications for disease progression

The functional heterogeneity and ecological niche of prostate cancer stem cells (PCSCs), which are major drivers of prostate cancer development and treatment resistance, have attracted considerable research attention. Cancer-associated fibroblasts (CAFs), which are crucial components of the tumor microenvironment (TME), substantially affect PCSC stemness. Additionally, CAFs promote PCSC growth and survival by releasing signaling molecules and modifying the surrounding environment. Conversely, PCSCs may affect the characteristics and behavior of CAFs by producing various molecules. This crosstalk mechanism is potentially crucial for prostate cancer progression and the development of treatment resistance. Using organoids to model the TME enables an in-depth study of CAF-PCSC interactions, providing a valuable preclinical tool to accurately evaluate potential target genes and design novel treatment strategies for prostate cancer. The objective of this review is to discuss the current research on the multilevel and multitarget regulatory mechanisms underlying CAF-PCSC interactions and crosstalk, aiming to inform therapeutic approaches that address challenges in prostate cancer treatment.

Expression of stem cell biomarker CD44 in oral squamous cell carcinoma and its association with lymph node metastasis and TNM staging

BACKGROUND

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers in the world. OSCC is a highly invasive lesion frequently having soaring morbidity as well as substantial mortality, attributed to resistance to therapy, metastasis, and recurrence driven by specific populations of cancer stem cells (CSC). The evidence of the association of expression of stem cell biomarker CD44 and metastatic potential of the tumor is inconclusive in OSCC and hence needs further evaluation.

OBJECTIVES

To determine the immunohistochemical expression of CD44 in OSCC and to find its association with lymph node metastasis and TNM staging.

MATERIALS AND METHODS

One hundred and five histologically proven cases of OSCC were studied. Histopathological parameters like depth of invasion, presence of lymph node metastasis, grading, and TNM staging were done according to the new AJCC staging criteria. Both intensity and proportion of CD44 expression were recorded.

RESULTS

The mean age observed in this study was 52.59 years with a male: female ratio of 1:3.76. Forty-nine cases (46.6%) showed a depth of invasion of more than 10 mm. Fifty-two out of one hundred and five cases (49%) had nodal involvement. TNM staging was 5.7%, 7.6%, 44.7%, and 42% for stages I, II, III, and IV, respectively. The majority of the cases (87.5%) showed CD44 expression in the tumor. There was a significant association between the CD44 expression and lymph node metastases (P < 0.001). Higher CD44 expression was seen in stages III and IV (P < 0.001).

CONCLUSION

CD44, a stem cell biomarker is significantly associated with higher TNM stage and lymph node metastases. This may be useful in predicting the tumor behavior in the small biopsy.

Immunotherapeutic Strategies Targeting Breast Cancer Stem Cells

Breast cancer is the most commonly diagnosed cancer in women and is a leading cause of cancer death in women worldwide. Despite the implementation of multiple treatment options, including immunotherapy, breast cancer treatment remains a challenge. In this review, we aim to summarize present challenges in breast cancer immunotherapy and recent advancements in overcoming treatment resistance. We elaborate on the inhibition of signaling cascades, such as the Notch, Hedgehog, Hippo, and WNT signaling pathways, which regulate the self-renewal and differentiation of breast cancer stem cells and, consequently, disease progression and survival. Cancer stem cells represent a rare population of cancer cells, likely originating from non-malignant stem or progenitor cells, with the ability to evade immune surveillance and develop resistance to immunotherapeutic treatments. We also discuss the interactions between breast cancer stem cells and the immune system, including potential agents targeting breast cancer stem cell-associated signaling pathways, and provide an overview of the emerging approaches to breast cancer stem cell-targeted immunotherapy. Finally, we consider the development of breast cancer vaccines and adoptive cellular therapies, which train the immune system to recognize tumor-associated antigens, for eliciting T cell-mediated responses to target breast cancer stem cells.

Targeted immunotherapy to cancer stem cells: A novel strategy of anticancer immunotherapy

Cancer is a major disease that endangers human health. Cancer drug resistance and relapse are the two main causes contributing to cancer treatment failure. Cancer stem cells (CSCs) are a small fraction of tumor cells that are responsible for tumorigenesis, metastasis, relapse, and resistance to conventional anticancer therapies. Therefore, CSCs are considered to be the root of cancer recurrence, metastasis, and drug resistance. Novel anticancer strategies need to face this new challenge and explore their efficacy against CSCs. Recently, immunotherapy has made rapid advances in cancer treatment, and its potential against CSCs is also an interesting area of research. Meanwhile, immunotherapy strategies are novel therapeutic modalities with promising results in targeting CSCs. In this review, we summarize the targeting of CSCs by various immunotherapy strategies such as monoclonal antibodies(mAb), tumor vaccines, immune checkpoint inhibitors, and chimeric antigen receptor-T cells(CAR-T) in pre-clinical and clinical studies. This review provides new insights into the application of these immunotherapeutic approaches to potential anti-tumor therapies in the future.

Identification and prognostic analysis of ferroptosis‑related gene HSPA5 to predict the progression of lung squamous cell carcinoma

Ferroptosis, an iron-dependent form of regulated cell death driven by excessive lipid peroxidation, is implicated in the development and therapeutic responses of cancer. However, the role of ferroptosis-related gene profiles in lung squamous cell carcinoma (LSCC) remains largely unknown. The present study aimed to identify the prognostic roles of ferroptosis-related genes in LSCC. Sequencing data from the Cancer Genome Atlas were analyzed and ferroptosis-related gene expression between tumor and para-tumor tissue was identified. The prognostic role of these genes was also assessed using Kaplan-Meier analyses and univariate and multivariate Cox proportional hazards regression model analyses. Immunological correlation, tumor stemness, drug sensitivity and the transcriptional differences of heat shock protein (HSP)A5 in LSCC were also analyzed. Thereafter, the expression of HSPA5 in 100 patients with metastatic LSCC was evaluated using immunohistochemistry (IHC) and the clinical significance of these markers with different risk factors was assessed. Of the 22 ferroptosis-related genes, the expression of HSPA5, HSPB1, glutathione peroxidase 4, Fanconi anemia complementation group D2, CDGSH iron sulfur domain 1, farnesyl-diphosphate farnesyltransferase 1, nuclear factor erythroid 2 like 2, solute carrier (SLC)1A5, ribosomal protein L8, nuclear receptor coactivator 4, transferrin receptor and SLC7A11 was significantly increased in LSCC compared with adjacent tissues. However, only high expression of HSPA5 was able to predict progression-free survival (PFS) and disease-free survival in LSCC. Although HSPA5 was also significantly elevated in patients with lung adenocarcinoma, HSPA5 expression did not predict the prognosis of patients with lung adenocarcinoma. Of note, a higher expression of HSPA5 was related to higher responses to chemotherapy but not to immunotherapy. In addition, HSPA5 expression was positively correlated with 'ferroptosis', 'cellular responses to hypoxia', 'tumor proliferation signature', 'G2M checkpoint', 'MYC targets' and 'TGFB'. IHC analysis also demonstrated that a high expression of HSPA5 in patients with metastatic LSCC in the study cohort was associated with shorter PFS and overall survival. In conclusion, the present study demonstrated that the expression of the ferroptosis-related gene HSPA5 may be a negative prognostic marker for LSCC.

Integrinβ-1 in disorders and cancers: molecular mechanisms and therapeutic targets

Integrinβ-1 (ITGB1) is a crucial member of the transmembrane glycoprotein signaling receptor family and is also central to the integrin family. It forms heterodimers with other ligands, participates in intracellular signaling and controls a variety of cellular processes, such as angiogenesis and the growth of neurons; because of its role in bidirectional signaling regulation both inside and outside the membrane, ITGB1 must interact with a multitude of substances, so a variety of interfering factors can affect ITGB1 and lead to changes in its function. Over the past 20 years, many studies have confirmed a clear causal relationship between ITGB1 dysregulation and cancer development and progression in a wide range of benign diseases and solid tumor types, which may imply that ITGB1 is a prognostic biomarker and a therapeutic target for cancer treatment that warrants further investigation. This review summarizes the biological roles of ITGB1 in benign diseases and cancers, and compiles the current status of ITGB1 function and therapy in various aspects of tumorigenesis and progression. Finally, future research directions and application prospects of ITGB1 are suggested. Video Abstract.

The Potential of Epigallocatechin Gallate in Targeting Cancer Stem Cells: A Comprehensive Review

The dreadful scenario of cancer prevails due to the presence of cancer stem cells (CSCs), which contribute to tumor growth, metastasis, invasion, resistance to chemo- and radiotherapy, and recurrence. CSCs are a small subpopulation of cells within the tumor that are characterized by self-renewal capability and have the potential to manifest heterogeneous lineages of cancer cells that constitute the tumor. The major bioactive green tea polyphenol (-)-epigallocatechin gallate (EGCG) has been fruitful in downgrading cancer stemness signaling and CSC biomarkers in cancer progression. EGCG has been evidenced to maneuver extrinsic and intrinsic apoptotic pathways in order to decrease the viability of CSCs. Cancer stemness is intricately related to epithelial-mesenchymal transition (EMT), metastasis and therapy resistance, and EGCG has been evidenced to regress all these CSC-related effects. By inhibiting CSC characteristics EGCG has also been evidenced to sensitize the tumor cells to radiotherapy and chemotherapy. However, the use of EGCG in in vitro and in vivo cancer models raises concern about its bioavailability, stability and efficacy against spheroids raised from parental cells. Therefore, novel nano formulations of EGCG and adjuvant therapy of EGCG with other phytochemicals or drugs or small molecules may have a better prospect in targeting CSCs. However, extensive clinical research is still awaited to elucidate a full proof impact of EGCG in cancer therapy.

Molecular heterogeneity in prostate cancer and the role of targeted therapy

Data collected from large-scale studies has shown that the incidence of prostate cancer globally is on the rise, which could be attributed to an overall increase in lifespan. So, the question is how has modern science with all its new technologies and clinical breakthroughs mitigated or managed this disease? The answer is not a simple one as prostate cancer exhibits various subtypes, each with its unique characteristics or signatures which creates challenges in treatment. To understand the complexity of prostate cancer these signatures must be deciphered. Molecular studies of prostate cancer samples have identified certain genetic and epigenetic alterations, which are instrumental in tumorigenesis. Some of these candidates include the androgen receptor (AR), various oncogenes, tumor suppressor genes, and the tumor microenvironment, which serve as major drivers that lead to cancer progression. These aberrant genes and their products can give an insight into prostate cancer development and progression by acting as potent markers to guide future therapeutic approaches. Thus, understanding the complexity of prostate cancer is crucial for targeting specific markers and tailoring treatments accordingly.

Sniping Cancer Stem Cells with Nanomaterials

Cancer stem cells (CSCs) drive tumor initiation, progression, and therapeutic resistance due to their self-renewal and differentiation capabilities. Despite encouraging progress in cancer treatment, conventional approaches often fail to eliminate CSCs, necessitating the development of precise targeted strategies. Recent advances in materials science and nanotechnology have enabled promising CSC-targeted approaches, harnessing the power of tailoring nanomaterials in diverse therapeutic applications. This review provides an update on the current landscape of nanobased precision targeting approaches against CSCs. We elucidate the nuanced application of organic, inorganic, and bioinspired nanomaterials across a spectrum of therapeutic paradigms, encompassing targeted therapy, immunotherapy, and multimodal synergistic therapies. By examining the accomplishments and challenges in this potential field, we aim to inform future efforts to advance nanomaterial-based therapies toward more effective "sniping" of CSCs and tumor clearance.

Cancer stem cells and their niche in cancer progression and therapy

High recurrence and metastasis rates and poor prognoses are the major challenges of current cancer therapy. Mounting evidence suggests that cancer stem cells (CSCs) play an important role in cancer development, chemoradiotherapy resistance, recurrence, and metastasis. Therefore, targeted CSC therapy has become a new strategy for solving the problems of cancer metastasis and recurrence. Since the properties of CSCs are regulated by the specific tumour microenvironment, the so-called CSC niche, which targets crosstalk between CSCs and their niches, is vital in our pursuit of new therapeutic opportunities to prevent cancer from recurring. In this review, we aim to highlight the factors within the CSC niche that have important roles in regulating CSC properties, including the extracellular matrix (ECM), stromal cells (e.g., associated macrophages (TAMs), cancer-associated fibroblasts (CAFs), and mesenchymal stem cells (MSCs)), and physiological changes (e.g., inflammation, hypoxia, and angiogenesis). We also discuss recent progress regarding therapies targeting CSCs and their niche to elucidate developments of more effective therapeutic strategies to eliminate cancer.

Integrative multi-omics analysis unveils stemness-associated molecular subtypes in prostate cancer and pan-cancer: prognostic and therapeutic significance

BACKGROUND

Prostate cancer (PCA) is the fifth leading cause of cancer-related deaths worldwide, with limited treatment options in the advanced stages. The immunosuppressive tumor microenvironment (TME) of PCA results in lower sensitivity to immunotherapy. Although molecular subtyping is expected to offer important clues for precision treatment of PCA, there is currently a shortage of dependable and effective molecular typing methods available for clinical practice. Therefore, we aim to propose a novel stemness-based classification approach to guide personalized clinical treatments, including immunotherapy.

METHODS

An integrative multi-omics analysis of PCA was performed to evaluate stemness-level heterogeneities. Unsupervised hierarchical clustering was used to classify PCAs based on stemness signature genes. To make stemness-based patient classification more clinically applicable, a stemness subtype predictor was jointly developed by using four PCA datasets and 76 machine learning algorithms.

RESULTS

We identified stemness signatures of PCA comprising 18 signaling pathways, by which we classified PCA samples into three stemness subtypes via unsupervised hierarchical clustering: low stemness (LS), medium stemness (MS), and high stemness (HS) subtypes. HS patients are sensitive to androgen deprivation therapy, taxanes, and immunotherapy and have the highest stemness, malignancy, tumor mutation load (TMB) levels, worst prognosis, and immunosuppression. LS patients are sensitive to platinum-based chemotherapy but resistant to immunotherapy and have the lowest stemness, malignancy, and TMB levels, best prognosis, and the highest immune infiltration. MS patients represent an intermediate status of stemness, malignancy, and TMB levels with a moderate prognosis. We further demonstrated that these three stemness subtypes are conserved across pan-tumor. Additionally, the 9-gene stemness subtype predictor we developed has a comparable capability to 18 signaling pathways to make tumor diagnosis and to predict tumor recurrence, metastasis, progression, prognosis, and efficacy of different treatments.

CONCLUSIONS

The three stemness subtypes we identified have the potential to be a powerful tool for clinical tumor molecular classification in PCA and pan-cancer, and to guide the selection of immunotherapy or other sensitive treatments for tumor patients.

Immunobiology of cancer stem cells and their immunoevasion mechanisms

Cancer stem cells (CSCs) defined as a small fraction of cells within malignancies have been isolated from tumors with different histological origins with stem related characteristics such as self-replicating potential, tumorigenesis, and therapy resistance. The dynamic communication between CSCs and tumor microenvironment particularly immune cells orchestrates their fate and plasticity as well as the patient outcome. According to recent evidence, it has been reported that they harness different immunological pathways to escape immunosurveillance and express aberrantly immunomodulatory agents or decreased levels of factors forming antigen presenting machinery (APM), subsequently followed by impaired antigen presentation and suppressed immune detection. As effective therapies are expected to be able to eradicate CSCs, mechanistic understanding of such interactions can provide insights into causes of therapy failure particularly in immunotherapy. Also, it can contribute to enhance the practical interventions against CSCs and their immunomodulatory features resulting in CSCs eradication and improving patient clinical outcome. The aim of this review is to explain the present knowledge regarding the immunobiology of CSCs and the immunoevasion mechanisms they use.

Rough neighborhood: Intricacies of cancer stem cells and infiltrating immune cell interaction in tumor microenvironment and potential in therapeutic targeting

Ongoing research on cellular heterogeneity of Cancer stem cells (CSCs) and its synergistic involvement with tumor milieu reveals enormous complexity, resulting in diverse hindrance in immune therapy. CSCs has captured attention for their contribution in shaping of tumor microenvironment and as target for therapeutic intervention. Recent studies have highlighted cell-extrinsic and intrinsic mechanisms of reciprocal interaction between tumor stroma constituents and CSCs. Therapeutic targeting requires an in-depth understanding of the underlying mechanisms involved with the rate limiting factors in tumor aggressiveness and pinpoint role of CSCs. Some of the major constituents of tumor microenvironment includes resident and infiltrating immune cell, both innate and adaptive. Some of these immune cells play crucial role as adjustors of tumor immune response. Tumor-adjustor immune cell interaction confer plasticity and features enabling tumor growth and metastasis in one hand and on the other hand blunts anti-tumor immunity. Detail understanding of CSC and TME resident immune cells interaction can shape new avenues for cancer immune therapy. In this review, we have tried to summarize the development of knowledge on cellular, molecular and functional interaction between CSCs and tumor microenvironment immune cells, highlighting immune-mediated therapeutic strategies aimed at CSCs. We also discussed developing a potential CSC and TME targeted therapeutic avenue.

Uncovering the Secrets of Prostate Cancer's Radiotherapy Resistance: Advances in Mechanism Research

Prostate cancer (PCa) is a critical global public health issue with its incidence on the rise. Radiation therapy holds a primary role in PCa treatment; however, radiation resistance has become increasingly challenging as we uncover more about PCa's pathogenesis. Our review aims to investigate the multifaceted mechanisms underlying radiation therapy resistance in PCa. Specifically, we will examine how various factors, such as cell cycle regulation, DNA damage repair, hypoxic conditions, oxidative stress, testosterone levels, epithelial-mesenchymal transition, and tumor stem cells, contribute to radiation therapy resistance. By exploring these mechanisms, we hope to offer new insights and directions towards overcoming the challenges of radiation therapy resistance in PCa. This can also provide a theoretical basis for the clinical application of novel ultra-high-dose-rate (FLASH) radiotherapy in the era of PCa.

SOX9 Modulates the Transformation of Gastric Stem Cells Through Biased Symmetric Cell Division

BACKGROUND & AIMS

Transformation of stem/progenitor cells has been associated with tumorigenesis in multiple tissues, but stem cells in the stomach have been hard to localize. We therefore aimed to use a combination of several markers to better target oncogenes to gastric stem cells and understand their behavior in the initial stages of gastric tumorigenesis.

METHODS

Mouse models of gastric metaplasia and cancer by targeting stem/progenitor cells were generated and analyzed with techniques including reanalysis of single-cell RNA sequencing and immunostaining. Gastric cancer cell organoids were genetically manipulated with clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) for functional studies. Cell division was determined by bromodeoxyuridine-chasing assay and the assessment of the orientation of the mitotic spindles. Gastric tissues from patients were examined by histopathology and immunostaining.

RESULTS

Oncogenic insults lead to expansion of SOX9+ progenitor cells in the mouse stomach. Genetic lineage tracing and organoid culture studies show that SOX9+ gastric epithelial cells overlap with SOX2+ progenitors and include stem cells that can self-renew and differentiate to generate all gastric epithelial cells. Moreover, oncogenic targeting of SOX9+SOX2+ cells leads to invasive gastric cancer in our novel mouse model (Sox2-CreERT;Sox9-loxp(66)-rtTA-T2A-Flpo-IRES-loxp(71);Kras(Frt-STOP-Frt-G12D);P53R172H), which combines Cre-loxp and Flippase-Frt genetic recombination systems. Sox9 deletion impedes the expansion of gastric progenitor cells and blocks neoplasia after Kras activation. Although Sox9 is not required for maintaining tissue homeostasis where asymmetric division predominates, loss of Sox9 in the setting of Kras activation leads to reduced symmetric cell division and effectively attenuates the Kras-dependent expansion of stem/progenitor cells. Similarly, Sox9 deletion in gastric cancer organoids reduces symmetric cell division, organoid number, and organoid size. In patients with gastric cancer, high levels of SOX9 are associated with recurrence and poor prognosis.

CONCLUSION

SOX9 marks gastric stem cells and modulates biased symmetric cell division, which appears to be required for the malignant transformation of gastric stem cells.

Cross-talk between cancer stem cells and immune cells: potential therapeutic targets in the tumor immune microenvironment

Ongoing research has revealed that the existence of cancer stem cells (CSCs) is one of the biggest obstacles in the current cancer therapy. CSCs make an influential function in tumor progression, recurrence and chemoresistance due to their typical stemness characteristics. CSCs are preferentially distributed in niches, and those niche sites exhibit characteristics typical of the tumor microenvironment (TME). The complex interactions between CSCs and TME illustrate these synergistic effects. The phenotypic heterogeneity within CSCs and the spatial interactions with the surrounding tumor microenvironment led to increased therapeutic challenges. CSCs interact with immune cells to protect themselves against immune clearance by exploiting the immunosuppressive function of multiple immune checkpoint molecules. CSCs also can protect themselves against immune surveillance by excreting extracellular vesicles (EVs), growth factors, metabolites and cytokines into the TME, thereby modulating the composition of the TME. Therefore, these interactions are also being considered for the therapeutic development of anti-tumor agents. We discuss here the immune molecular mechanisms of CSCs and comprehensively review the interplay between CSCs and the immune system. Thus, studies on this topic seem to provide novel ideas for reinvigorating therapeutic approaches to cancer.

Integrins in human hepatocellular carcinoma tumorigenesis and therapy

ABSTRACT

Integrins are a family of transmembrane receptors that connect the extracellular matrix and actin skeleton, which mediate cell adhesion, migration, signal transduction, and gene transcription. As a bi-directional signaling molecule, integrins can modulate many aspects of tumorigenesis, including tumor growth, invasion, angiogenesis, metastasis, and therapeutic resistance. Therefore, integrins have a great potential as antitumor therapeutic targets. In this review, we summarize the recent reports of integrins in human hepatocellular carcinoma (HCC), focusing on the abnormal expression, activation, and signaling of integrins in cancer cells as well as their roles in other cells in the tumor microenvironment. We also discuss the regulation and functions of integrins in hepatitis B virus-related HCC. Finally, we update the clinical and preclinical studies of integrin-related drugs in the treatment of HCC.

Cancer Stem Cell Relationship with Pro-Tumoral Inflammatory Microenvironment

Inflammatory processes and cancer stem cells (CSCs) are increasingly recognized as factors in the development of tumors. Emerging evidence indicates that CSCs are associated with cancer properties such as metastasis, treatment resistance, and disease recurrence. However, the precise interaction between CSCs and the immune microenvironment remains unexplored. Although evasion of the immune system by CSCs has been extensively studied, new research demonstrates that CSCs can also control and even profit from the immune response. This review provides an overview of the reciprocal interplay between CSCs and tumor-infiltrating immune cells, collecting pertinent data about how CSCs stimulate leukocyte reprogramming, resulting in pro-tumor immune cells that promote metastasis, chemoresistance, tumorigenicity, and even a rise in the number of CSCs. Tumor-associated macrophages, neutrophils, Th17 and regulatory T cells, mesenchymal stem cells, and cancer-associated fibroblasts, as well as the signaling pathways involved in these pro-tumor activities, are among the immune cells studied. Although cytotoxic leukocytes have the potential to eliminate CSCs, immune evasion mechanisms in CSCs and their clinical implications are also known. We intended to compile experimental findings that provide direct evidence of interactions between CSCs and the immune system and CSCs and the inflammatory milieu. In addition, we aimed to summarize key concepts in order to comprehend the cross-talk between CSCs and the tumor microenvironment as a crucial process for the effective design of anti-CSC therapies.

Overexpression of LAG3, TIM3, and A2aR in adenoid cystic carcinoma and mucoepidermoid carcinoma

OBJECTIVE

Adenoid cystic carcinoma (AdCC) and mucoepidermoid carcinoma (MEC) are the two most frequent malignancies of salivary glands. This study aims to explore the expression and migration of LAG3, TIM3, and A2aR in AdCC and MEC, and the potential relationship with oncogenic signaling molecules and immunosuppressive cytokines.

MATERIALS AND METHODS

Custom made human salivary gland tissue microarrays included 81 AdCCs, 52 MECs, 76 normal salivary glands (NSG), and 14 pleomorphic adenoma (PMA) samples. Immunohistochemical analysis of lymphocyte activation gene 3 (LAG3), T-cell immunoglobulin and mucin domain-containing protein 3 (TIM3), adenosine 2a receptor (A2aR), oncogenic phosphorylated S6 kinase (p-S6) and ERK1/2 (p-ERK1/2 ), and TGF-β1 was performed with salivary gland tissue microarrays of human samples. The correlation of the immunostaining was analyzed based on a digital pathological system, and data were evaluated by hierarchical cluster. Further in vitro studies of knockdown immune checkpoints LAG3, TIM3, and A2aR were carried out by siRNA transfection.

RESULTS

The expression levels of LAG3, TIM3, and A2aR were remarkably increased in AdCC and MEC, compared with NSG and PMA samples, but were independent of pathology grade. They were closely correlated with TGF-β1, slightly related to p-ERK1/2 and p-S6. After the knockdown of immune checkpoints LAG3, TIM3, and A2aR, the migration of SACC-LM cell line was significantly reduced.

CONCLUSIONS

These results suggested that LAG3, TIM3, and A2aR are overexpressed in AdCC and MEC, may promote migration of SACC-LM cell and correlated with TGF-β1 and oncogenic signaling pathways.

Current understanding of cancer stem cells: Immune evasion and targeted immunotherapy in gastrointestinal malignancies

As a relatively rare population of cancer cells existing in the tumor microenvironment, cancer stem cells (CSCs) possess properties of immune privilege to evade the attack of immune system, regulated by the microenvironment of CSCs, the so-called CSCs niche. The bidirectional interaction of CSCs with tumor microenvironment (TME) components favors an immunosuppressive shelter for CSCs' survival and maintenance. Gastrointestinal cancer stem cells (GCSCs) are broadly regarded to be intimately involved in tumor initiation, progression, metastasis and recurrence, with elevated tumor resistance to conventional therapies, which pose a major hindrance to the clinical efficacy for treated patients with gastrointestinal malignancies. Thus, a multitude of efforts have been made to combat and eradicate GCSCs within the tumor mass. Among diverse methods of targeting CSCs in gastrointestinal malignancies, immunotherapy represents a promising strategy. And the better understanding of GCSCs immunomodulation and immunoresistance mechanisms is beneficial to guide and design novel GCSCs-specific immunotherapies with enhanced immune response and clinical efficacy. In this review, we have gathered available and updated information to present an overview of the immunoevasion features harbored by cancer stem cells, and we focus on the description of immune escape strategies utilized by CSCs and microenvironmental regulations underlying CSCs immuno-suppression in the context of gastrointestinal malignancies. Importantly, this review offers deep insights into recent advances of CSC-targeting immunotherapeutic approaches in gastrointestinal cancers.

An overview of prostate cancer (PCa) diagnosis: Potential role of miRNAs

Prostate cancer is the second most frequently diagnosed cancer among men worldwide, with the estimated sixth leading cause of cancer death. Despite major advancements in clinical biology and imaging, digital rectal examination (DRE), prostate-specific antigen (PSA), and biopsies indication remain the keystone for screening. Several kits are used to detect genomic changes and non-coding RNAs in the sample. However, its indication remains controversial for screening purposes. There is an urged need for non-invasive biomarkers to implement precision medicine. Recent research shows that miRNAs have an important role in the diagnostic, prognostic, and therapeutic agents as non-invasive biomarkers. Though prostate cancer data remains controversial in other cancer types, such as breast cancer, miR-21 expression is upregulated. Here, we reported a prolonged revision of miRNAs as prostate cancer prognostic, diagnostic, and predictive tools, including data on androgen receptor (AR) signaling, epithelial-mesenchymal transition (EMT) process, and cancer stem cells (CSCs) regulation. The combined utilization of miRNAs with other tests will help patients and clinicians to select the most appropriate personalized treatment and to avoid overdiagnosis and unnecessary biopsies. Future clinical applications of our reported novel miRNAs have a substantial role in the primary diagnosis of prostate cancer to help treatment decisions.

Signaling pathways in the regulation of cancer stem cells and associated targeted therapy

Cancer stem cells (CSCs) are defined as a subpopulation of malignant tumor cells with selective capacities for tumor initiation, self-renewal, metastasis, and unlimited growth into bulks, which are believed as a major cause of progressive tumor phenotypes, including recurrence, metastasis, and treatment failure. A number of signaling pathways are involved in the maintenance of stem cell properties and survival of CSCs, including well-established intrinsic pathways, such as the Notch, Wnt, and Hedgehog signaling, and extrinsic pathways, such as the vascular microenvironment and tumor-associated immune cells. There is also intricate crosstalk between these signal cascades and other oncogenic pathways. Thus, targeting pathway molecules that regulate CSCs provides a new option for the treatment of therapy-resistant or -refractory tumors. These treatments include small molecule inhibitors, monoclonal antibodies that target key signaling in CSCs, as well as CSC-directed immunotherapies that harness the immune systems to target CSCs. This review aims to provide an overview of the regulating networks and their immune interactions involved in CSC development. We also address the update on the development of CSC-directed therapeutics, with a special focus on those with application approval or under clinical evaluation.

Prostate cancer as a dedifferentiated organ: androgen receptor, cancer stem cells, and cancer stemness

Cancer progression is characterized and driven by gradual loss of a differentiated phenotype and gain of stem cell-like features. In prostate cancer (PCa), androgen receptor (AR) signaling is important for cancer growth, progression, and emergence of therapy resistance. Targeting the AR signaling axis has been, over the decades, the mainstay of PCa therapy. However, AR signaling at the transcription level is reduced in high-grade cancer relative to low-grade PCa and loss of AR expression promotes a stem cell-like phenotype, suggesting that emergence of resistance to AR-targeted therapy may be associated with loss of AR signaling and gain of stemness. In the present mini-review, we first discuss PCa from the perspective of an abnormal organ with increasingly deregulated differentiation, and discuss the role of AR signaling during PCa progression. We then focus on the relationship between prostate cancer stem cells (PCSCs) and AR signaling. We further elaborate on the current methods of using transcriptome-based stemness-enriched signature to evaluate the degree of oncogenic dedifferentiation (cancer stemness) in pan-cancer datasets, and present the clinical significance of scoring transcriptome-based stemness across the spectrum of PCa development. Our discussions highlight the importance to evaluate the dynamic changes in both stem cell-like features (stemness score) and AR signaling activity across the PCa spectrum.

The metabolic addiction of cancer stem cells

Cancer stem cells (CSC) are the minor population of cancer originating cells that have the capacity of self-renewal, differentiation, and tumorigenicity (when transplanted into an immunocompromised animal). These low-copy number cell populations are believed to be resistant to conventional chemo and radiotherapy. It was reported that metabolic adaptation of these elusive cell populations is to a large extent responsible for their survival and distant metastasis. Warburg effect is a hallmark of most cancer in which the cancer cells prefer to metabolize glucose anaerobically, even under normoxic conditions. Warburg's aerobic glycolysis produces ATP efficiently promoting cell proliferation by reprogramming metabolism to increase glucose uptake and stimulating lactate production. This metabolic adaptation also seems to contribute to chemoresistance and immune evasion, a prerequisite for cancer cell survival and proliferation. Though we know a lot about metabolic fine-tuning in cancer, what is still in shadow is the identity of upstream regulators that orchestrates this process. Epigenetic modification of key metabolic enzymes seems to play a decisive role in this. By altering the metabolic flux, cancer cells polarize the biochemical reactions to selectively generate "onco-metabolites" that provide an added advantage for cell proliferation and survival. In this review, we explored the metabolic-epigenetic circuity in relation to cancer growth and proliferation and establish the fact how cancer cells may be addicted to specific metabolic pathways to meet their needs. Interestingly, even the immune system is re-calibrated to adapt to this altered scenario. Knowing the details is crucial for selective targeting of cancer stem cells by choking the rate-limiting stems and crucial branch points, preventing the formation of onco-metabolites.

Understanding and targeting prostate cancer cell heterogeneity and plasticity

Prostate cancer (PCa) is a prevalent malignancy that occurs primarily in old males. Prostate tumors in different patients manifest significant inter-patient heterogeneity with respect to histo-morphological presentations and molecular architecture. An individual patient tumor also harbors genetically distinct clones in which PCa cells display intra-tumor heterogeneity in molecular features and phenotypic marker expression. This inherent PCa cell heterogeneity, e.g., in the expression of androgen receptor (AR), constitutes a barrier to the long-term therapeutic efficacy of AR-targeting therapies. Furthermore, tumor progression as well as therapeutic treatments induce PCa cell plasticity such that AR-positive PCa cells may turn into AR-negative cells and prostate tumors may switch lineage identity from adenocarcinomas to neuroendocrine-like tumors. This induced PCa cell plasticity similarly confers resistance to AR-targeting and other therapies. In this review, I first discuss PCa from the perspective of an abnormal organ development and deregulated cellular differentiation, and discuss the luminal progenitor cells as the likely cells of origin for PCa. I then focus on intrinsic PCa cell heterogeneity in treatment-naïve tumors with the presence of prostate cancer stem cells (PCSCs). I further elaborate on PCa cell plasticity induced by genetic alterations and therapeutic interventions, and present potential strategies to therapeutically tackle PCa cell heterogeneity and plasticity. My discussions will make it clear that, to achieve enduring clinical efficacy, both intrinsic PCa cell heterogeneity and induced PCa cell plasticity need to be targeted with novel combinatorial approaches.

Nano-Based Approved Pharmaceuticals for Cancer Treatment: Present and Future Challenges

Cancer is one of the main causes of death worldwide. To date, and despite the advances in conventional treatment options, therapy in cancer is still far from optimal due to the non-specific systemic biodistribution of antitumor agents. The inadequate drug concentrations at the tumor site led to an increased incidence of multiple drug resistance and the appearance of many severe undesirable side effects. Nanotechnology, through the development of nanoscale-based pharmaceuticals, has emerged to provide new and innovative drugs to overcome these limitations. In this review, we provide an overview of the approved nanomedicine for cancer treatment and the rationale behind their designs and applications. We also highlight the new approaches that are currently under investigation and the perspectives and challenges for nanopharmaceuticals, focusing on the tumor microenvironment and tumor disseminate cells as the most attractive and effective strategies for cancer treatments.

Lung Cancer Stem Cells and Their Clinical Implications

It is now widely accepted that stem cells exist in various cancers, including lung cancer, which are referred to as cancer stem cells (CSCs). CSCs are defined in this context as the subset of tumor cells with the ability to form tumors in serial transplantation and cloning assays and form tumors at metastatic sites. Mouse models of lung cancer have shown that lung CSCs reside in niches that are essential for the maintenance of stemness, plasticity, enable antitumor immune evasion, and provide metastatic potential. Similar to normal lung stem cells, Notch, Wnt, and the Hedgehog signaling cascades have been recruited by the CSCs to regulate stemness and also provide therapy-driven resistance in lung cancer. Compounds targeting β-catenin and Sonic hedgehog (Shh) activity have shown promising anti-CSC activity in preclinical murine models of lung cancer. Understanding CSCs and their niches in lung cancer can answer fundamental questions pertaining to tumor maintenance and associated immune regulation and escape that appear important in the quest to develop novel lung cancer therapies and enhance sensitivity to currently approved chemo-, targeted-, and immune therapeutics.

Effects of noncoding RNAs in radiotherapy response in breast cancer: a systematic review

Radiotherapy has an essential role in breast cancer treatment. However, tumor cells may be resistant to radiotherapy. Noncoding RNAs are considered regulators of different pathways which modulate radiotherapy. This systematic review classifies long noncoding RNAs, and microRNAs precipitated in the radiation response of breast cancer patients. A total of 14 microRNAs and 8 long noncoding RNAs were studied in this review. MiR-22, miR-200 c, Let7, and LINP1 as tumor suppressors increase the effect of radiotherapy in BC. However, some noncoding RNAs such as HOTAIR, NEAT1, and miR-21 are precipitated in radio-resistance breast cancers. Significant changes in the pattern of noncoding RNAs expression before and after radiotherapy make them a good candidate for the prognosis and prediction of radiotherapy response. MiR-21 and miR-182 can promote radio-resistance via cancer stem cells. At last, the molecular mechanisms initiating radio-resistance were also examined to find the candidate noncoding RNAs for the development of radiation-sensitized agents.

Signaling Pathways and Targeted Therapies for Stem Cells in Prostate Cancer

Prostate cancer (PCa) is one of the most frequently occurring cancers among men, and the current statistics show that it is the second leading cause of cancer-related deaths among men. Over the years, research in PCa treatment and therapies has made many advances. Despite these efforts, the standardized therapies such as radiation, chemotherapy, hormonal therapy and surgery are not considered completely effective in treating advanced and metastatic PCa. In most situations, fast-dividing tumor cells are targeted, leaving behind relatively slowly dividing, chemoresistant cells known as cancer stem cells. Therefore, following the seemingly successful treatments, the lingering quiescent cancer stem cells are able to renew themselves, undergo differentiation into mature tumor cells, and sufficiently reinitiate the disease, leading to cancer relapse. Thus, prostate cancer stem cells (PCSCs) have been reported to play a vital role in controlling the dynamics of tumorigenesis, progression, and resistance to therapies in PCa. However, the complete knowledge on the mechanisms regulating the stemness of PCSCs is still unclear. Thus, studying the stemness of PCSCs will allow for the development of more effective cancer therapies due to the durable response, resulting in a reduction in recurrences of cancer. In this Review, we will specifically describe the molecular mechanisms responsible for regulating the stemness of PCSCs. Furthermore, current developments in stem cell-specific therapeutic approaches along with future prospects will also be discussed.

A m6Avalue predictive of prostate cancer stemness, tumor immune landscape and immunotherapy response

The molecular mechanisms underpinning prostate cancer (PCa) progression are incompletely understood, and precise stratification of aggressive primary PCa (pri-PCa) from indolent ones poses a major clinical challenge. Here, we comprehensively dissect, genomically and transcriptomically, the m⁶A (N ⁶-methyladenosine) pathway as a whole in PCa. Expression, but not the genomic alteration, repertoire of the full set of 24 m⁶A regulators at the population level successfully stratifies pri-PCa into three m⁶A clusters with distinct molecular and clinical features. These three m⁶A modification patterns closely correlate with androgen receptor signaling, stemness, proliferation and tumor immunogenicity of cancer cells, and stroma activity and immune landscape of tumor microenvironment (TME). We observe a discrepancy between a potentially higher neoantigen production and a deficiency in antigen presentation processes in aggressive PCa, offering insights into the failure of immunotherapy. Identification of PCa-specific m⁶A phenotype-associated genes provides a basis for construction of m⁶Avalue to measure m⁶A methylation patterns in individual patients. Tumors with lower m⁶Avalue are relatively indolent with abundant immune cell infiltration and stroma activity. Interestingly, m⁶Avalue separates PCa TME into fibrotic and nonfibrotic phenotypes (instead of previously reported immune-proficient or -desert phenotypes in other cancer types). Significantly, m⁶Avalue can be used to predict drug response and clinical immunotherapy efficacy in both castration-resistant PCa and other cancer types. Therefore, our study establishes m⁶A methylation modification pattern as a determinant in PCa progression via impacting cancer cell aggressiveness and TME remodeling.

The Effect of Hypoxia and Hypoxia-Associated Pathways in the Regulation of Antitumor Response: Friends or Foes?

Hypoxia is an environmental stressor that is instigated by low oxygen availability. It fuels the progression of solid tumors by driving tumor plasticity, heterogeneity, stemness and genomic instability. Hypoxia metabolically reprograms the tumor microenvironment (TME), adding insult to injury to the acidic, nutrient deprived and poorly vascularized conditions that act to dampen immune cell function. Through its impact on key cancer hallmarks and by creating a physical barrier conducive to tumor survival, hypoxia modulates tumor cell escape from the mounted immune response. The tumor cell-immune cell crosstalk in the context of a hypoxic TME tips the balance towards a cold and immunosuppressed microenvironment that is resistant to immune checkpoint inhibitors (ICI). Nonetheless, evidence is emerging that could make hypoxia an asset for improving response to ICI. Tackling the tumor immune contexture has taken on an in silico, digitalized approach with an increasing number of studies applying bioinformatics to deconvolute the cellular and non-cellular elements of the TME. Such approaches have additionally been combined with signature-based proxies of hypoxia to further dissect the turbulent hypoxia-immune relationship. In this review we will be highlighting the mechanisms by which hypoxia impacts immune cell functions and how that could translate to predicting response to immunotherapy in an era of machine learning and computational biology.

Antitumor activity of T cells secreting αCD133-αCD3 bispecific T-cell engager against cholangiocarcinoma

Cholangiocarcinoma (CCA) is a lethal cancer of bile duct epithelial cells with a high mortality rate and limited therapeutic options. An effective treatment is, therefore, urgently needed to improve treatment outcomes for these patients. To develop a new therapeutic option, we engineered T cells secreting αCD133-αCD3 bispecific T-cell engager and evaluated their antitumor effects against CD133-expressing CCA cells. The cDNA encoding αCD133-αCD3 bispecific T-cell engager (αCD133-αCD3-ENG) was cloned into pCDH lentiviral construct and its expression was tested in Lenti-X 293T cells. T cells from healthy donors were then transduced with engineered lentiviruses to create T cells secreting αCD133-αCD3 engager to evaluate their antitumor activities. The average transduction efficiency into T cells was approximately 60.03±21.65%. In the co-culture system containing T cells secreting αCD133-αCD3 engager (as effector cells) and mWasabi-luciferase-expressing CCA cells (KKU-100 and KKU-213A; as target cells), the effector T cells exhibited significantly higher cytolytic activities against the target CCA cells (49.0±9.76% and 64.10±13.18%, respectively) than those observed against the untransduced T cells (10.97±10.65%; p = 0.0103 and 9.80±11.05%; p = 0.0054) at an effector-to-target ratio of 5:1. In addition, the secreted αCD133-αCD3 engager significantly redirected both transduced T cells and bystander T cells to kill the target CCA cells (up to 73.20±1.68%; p<0.05). Moreover, the transduced and bystander T cells could kill the target CCA spheroids at a rate approximately 5-fold higher than that of the no treatment control condition (p = 0.0011). Our findings demonstrate proof-of-principle that T cells secreting αCD133-αCD3 engager can be an alternative approach to treating CD133-positive CCA, and they pave the way for future in vivo study and clinical trials.

LncRNAs, the Molecules Involved in Communications With Colorectal Cancer Stem Cells

Colorectal cancer stem cells (CRCSCs) can actively self-renew, as well as having multidirectional differentiation and tumor regeneration abilities. Because the high functional activities of CRCSCs are associated with low cure rates in patients with colorectal cancer, efforts have sought to determine the function and regulatory mechanisms of CRCSCs. To date, however, the potential regulatory mechanisms of CRCSCs remain incompletely understood. Many non-coding genes are involved in tumor invasion and spread through their regulation of CRCSCs, with long non-coding RNAs (lncRNAs) being important non-coding RNAs. LncRNAs may be involved in the colorectal cancer development and drug resistance through their regulation of CRCSCs. This review systematically evaluates the latest research on the ability of lncRNAs to regulate CRCSC signaling pathways and the involvement of these lncRNAs in colorectal cancer promotion and suppression. The regulatory network of lncRNAs in the CRCSC signaling pathway has been determined. Further analysis of the potential clinical applications of lncRNAs as novel clinical diagnostic and prognostic biomarkers and therapeutic targets for colorectal cancer may provide new ideas and protocols for the prevention and treatment of colorectal cancer.

CRISPR System-Linked Self-Assembling Nanoplatforms for Inspection and Screening of Gastric Cancer Stem Cells

Cancer stem cells (CSCs) possess a high degree of plasticity, constituting a formidable challenge to identify and screen CSCs in situ with outstanding specificity and sensitivity. To overcome this limitation, a self-assembled heterodimer consisting of clustered regularly interspaced short palindromic repeats/Cas12a (named A-CCA) linkage is designed for in situ identification and screening of gastric CSCs (GCSCs) from gastric cancer cells (GCCs). In this system, the editable character of crRNA performs recognition of dual-targets in GCSCs, effectively boosting the specificity of identification, while the enzymatic reaction of Cas12a contributes meaningfully to the sensitivity of sensing, enabling in situ examination and screening of GCSCs. Specifically, the A-CCA nanoplatforms hybridized with ABCG 2 and ABCB 1 overexpress in GCSCs, which can generate heterodimers and simultaneously restore the function of trans-cleavage. At this time, the asymmetry of the heterodimer causes a circular dichroism signal, which together with the recovered fluorescence signal form a dual-signals output system that can further ensure the precision of screening GCSC. Therefore, fluorescence-enhanced GCSCs can be sorted out from GCCs by flow cytometry. Furthermore, GCSCs screened by this assay possess extremely aggressive tumorigenic efficiency, providing a fundamental research object for further developing CSC targeted drugs in vivo.

The Role of the Renin-Angiotensin System in the Cancer Stem Cell Niche

Cancer stem cells (CSCs) drive metastasis, treatment resistance, and tumor recurrence. CSCs reside within a niche, an anatomically distinct site within the tumor microenvironment (TME) that consists of malignant and non-malignant cells, including immune cells. The renin-angiotensin system (RAS), a critical regulator of stem cells and key developmental processes, plays a vital role in the TME. Non-malignant cells within the CSC niche and stem cell signaling pathways such as the Wnt, Hedgehog, and Notch pathways influence CSCs. Components of the RAS and cathepsins B and D that constitute bypass loops of the RAS are expressed on CSCs in many cancer types. There is extensive in vitro and in vivo evidence showing that RAS inhibition reduces tumor growth, cell proliferation, invasion, and metastasis. However, there is inconsistent epidemiological data on the effect of RAS inhibitors on cancer incidence and survival outcomes, attributed to different patient characteristics and methodologies used between studies. Further mechanistic studies are warranted to investigate the precise effects of the RAS on CSCs directly and/or the CSC niche. Targeting the RAS, its bypass loops, and convergent signaling pathways participating in the TME and other key stem cell pathways that regulate CSCs may be a novel approach to cancer treatment.

The potential prognostic values of the ADAMTS-like protein family: an integrative pan-cancer analysis

Background

A disintegrin-like and metalloproteinase domain with thrombospondin type 1 motifs (ADAMTS)-like proteins, including ADAMTSL1-6 and papilin, which are part of the mammalian ADAMTS superfamily, appear to be relevant to extracellular matrix function and the regulation of ADAMTS protease activity. Their roles in tumor initiation and progression and regulating the tumor microenvironment (TME) are now recognized.

Methods

In the present study, a comprehensive investigation of the pan-cancer effects of ADAMTSLs and their associations with patient survival, drug responses, and the TME was performed by integrating The Cancer Genome Atlas (TCGA) data and annotated data resources.

Results

The expression of ADAMTSL family members was found to be dysregulated in many cancer types. More importantly, their expression was frequently associated with patients’ overall survival (OS), drug responses, and the TME. ADAMTSL1, ADAMTSL4, and ADAMTSL5 were primarily associated with aggressive phenotypes, while PAPLN was more frequently associated with a favorable prognosis. In a non-small cell lung cancer (NSCLC) cohort, Thrombospondin Type 1 Domain Containing 4 (THSD4) (ADAMTSL6) and Papilin (PAPLN) were associated with immune checkpoint inhibitor (ICI) sensitivity in samples from the Gene Expression Omnibus repository (GSE135222). Twenty and 30 proteins related to THSD4 and PAPLN, respectively, were identified through a proteomic analysis of 18 Chinese lung adenocarcinoma patients.

Conclusions

Our findings extend understandings of the role of the ADAMTSL family in cancers and are a valuable resource on their clinical utility. This article provides insight into the clinical importance of next-generation sequencing technology to identify novel biomarkers for prognosis and investigate therapeutic strategy for clinical benefit.

A Novel S100 Family-Based Signature Associated with Prognosis and Immune Microenvironment in Glioma

Background

Glioma is the most common central nervous system (CNS) cancer with a short survival period and a poor prognosis. The S100 family gene, comprising 25 members, relates to diverse biological processes of human malignancies. Nonetheless, the significance of S100 genes in predicting the prognosis of glioma remains largely unclear. We aimed to build an S100 family-based signature for glioma prognosis.

Methods

We downloaded 665 and 313 glioma patients, respectively, from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) database with RNAseq data and clinical information. This study established a prognostic signature based on the S100 family genes through multivariate COX and LASSO regression. The Kaplan-Meier curve was plotted to compare overall survival (OS) among groups, whereas Receiver Operating Characteristic (ROC) analysis was performed to evaluate model accuracy. A representative gene S100B was further verified by in vitro experiments.

Results

An S100 family-based signature comprising 5 genes was constructed to predict the glioma that stratified TCGA-derived cases as a low- or high-risk group, whereas the significance of prognosis was verified based on CGGA-derived cases. Kaplan-Meier analysis revealed that the high-risk group was associated with the dismal prognosis. Furthermore, the S100 family-based signature was proved to be closely related to immune microenvironment. In vitro analysis showed S100B gene in the signature promoted glioblastoma (GBM) cell proliferation and migration.

Conclusions

We constructed and verified a novel S100 family-based signature associated with tumor immune microenvironment (TIME), which may shed novel light on the glioma diagnosis and treatment.

Integrins regulate stemness in solid tumor: an emerging therapeutic target

Integrins are the adhesion molecules and transmembrane receptors that consist of α and β subunits. After binding to extracellular matrix components, integrins trigger intracellular signaling and regulate a wide spectrum of cellular functions, including cell survival, proliferation, differentiation and migration. Since the pattern of integrins expression is a key determinant of cell behavior in response to microenvironmental cues, deregulation of integrins caused by various mechanisms has been causally linked to cancer development and progression in several solid tumor types. In this review, we discuss the integrin signalosome with a highlight of a few key pro-oncogenic pathways elicited by integrins, and uncover the mutational and transcriptomic landscape of integrin-encoding genes across human cancers. In addition, we focus on the integrin-mediated control of cancer stem cell and tumor stemness in general, such as tumor initiation, epithelial plasticity, organotropic metastasis and drug resistance. With insights into how integrins contribute to the stem-like functions, we now gain better understanding of the integrin signalosome, which will greatly assist novel therapeutic development and more precise clinical decisions.

Characterization of gastric cancer stem-like molecular features, immune and pharmacogenomic landscapes

Cancer stem cells (CSCs) actively reprogram their tumor microenvironment (TME) to sustain a supportive niche, which may have a dramatic impact on prognosis and immunotherapy. However, our knowledge of the landscape of the gastric cancer stem-like cell (GCSC) microenvironment needs to be further improved. A multi-step process of machine learning approaches was performed to develop and validate the prognostic and predictive potential of the GCSC-related score (GCScore). The high GCScore subgroup was not only associated with stem cell characteristics, but also with a potential immune escape mechanism. Furthermore, we experimentally demonstrated the upregulated infiltration of CD206+ tumor-associated macrophages (TAMs) in the invasive margin region, which in turn maintained the stem cell properties of tumor cells. Finally, we proposed that the GCScore showed a robust capacity for prediction for immunotherapy, and investigated potential therapeutic targets and compounds for patients with a high GCScore. The results indicate that the proposed GCScore can be a promising predictor of prognosis and responses to immunotherapy, which provides new strategies for the precision treatment of GCSCs.