Tackling the cancer stem cells - what challenges do they pose?

The Metabolic Landscape of Cancer Stem Cells: Insights and Implications for Therapy

Cancer stem cells (CSCs) are a subpopulation with self-renewal and differentiation capacities believed to be responsible for tumor initiation, progression, and recurrence. These cells exhibit unique metabolic features that contribute to their stemness and survival in hostile tumor microenvironments. Like non-stem cancer cells, CSCs primarily rely on glycolysis for ATP production, akin to the Warburg effect. However, CSCs also show increased dependence on alternative metabolic pathways, such as oxidative phosphorylation (OXPHOS) and fatty acid metabolism, which provide necessary energy and building blocks for self-renewal and therapy resistance. The metabolic plasticity of CSCs enables them to adapt to fluctuating nutrient availability and hypoxic conditions within the tumor. Recent studies highlight the importance of these metabolic shifts in maintaining the CSC phenotype and promoting cancer progression. The CSC model suggests that a small, metabolically adaptable subpopulation drives tumor growth and therapy resistance. CSCs can switch between glycolysis and mitochondrial metabolism, enhancing their survival under stress and dormant states. Targeting CSC metabolism offers a promising therapeutic strategy; however, their adaptability complicates eradication. A multi-targeted approach addressing various metabolic pathways is essential for effective CSC elimination, underscoring the need for further research into specific CSC markers and mechanisms that distinguish their metabolism from normal stem cells for successful therapeutic intervention.

Chromatin Organization Governs Transcriptional Response and Plasticity of Cancer Stem Cells

Chromatin organization regulates transcription to influence cellular plasticity and cell fate. We explored whether chromatin nanoscale packing domains are involved in stemness and response to chemotherapy. Using an optical spectroscopic nanosensing technology we show that ovarian cancer-derived cancer stem cells (CSCs) display upregulation of nanoscale chromatin packing domains compared to non-CSCs. Cleavage under targets and tagmentation (CUT&Tag) sequencing with antibodies for repressive H3K27me3 and active H3K4me3 and H3K27ac marks mapped chromatin regions associated with differentially expressed genes. More poised genes marked by both H3K4me3 and H3K27me3 were identified in CSCs vs. non-CSCs, supporting increased transcriptional plasticity of CSCs. Pathways related to Wnt signaling and cytokine-cytokine receptor interaction were repressed in non-CSCs, while retinol metabolism and antioxidant response were activated in CSCs. Comparative transcriptomic analyses showed higher intercellular transcriptional heterogeneity at baseline in CSCs. In response to cisplatin, genes with low baseline expression levels underwent the highest upregulation in CSCs, demonstrating transcriptional plasticity under stress. Epigenome targeting drugs downregulated chromatin packing domains and promoted cellular differentiation. A disruptor of telomeric silencing 1-like (Dot1L) inhibitor blocked transcriptional plasticity, reversing stemness. These findings support that CSCs harbor upregulated chromatin packing domains, contributing to transcriptional and cell plasticity that epigenome modifiers can target.

Molecular and phenotypic characterization of 5-FU resistant colorectal cancer cells: toward enrichment of cancer stem cells

Cancer stem cells (CSCs) as a subgroup of cells within a tumor capable of self-renewal, thereby driving tumor initiation and spread. Addressing treatment failures in cancer, linked to CSCs and their resistance mechanisms, requires effective preclinical models for testing targeted therapies. Caco2- and HT-29-resistant cells were generated by repeated treatment of cells with growing concentrations of 5-fluorouracil (5-FU) anticancer drug for an extended time. The sensitivity of 5-FU-resistant cells was evaluated by cytotoxicity assay. Stemness, epithelial-mesenchymal transition (EMT), migration and drug resistance characteristics were assessed through gene expression investigation by real-time PCR. The expression of CD44, CD133, and CD66 were evaluated by flow cytometry. To end, the bioinformatic analysis estimated the molecular function and biological pathways considering the differential expression of selected genes and proteins. 5-FU-exposed cells displayed increased resistance to 5-FU. The gene expression analysis showed an upregulation of stemness genes (KLF4, SOX2, OCT4, C-MYC), enhanced scavenging system, and elevated expression of CSC surface markers (CD44 and CD133) compared to parental cells. Additionally, pro-EMT genes (TWIST1, SNAIL1, ZEB1, Vimentin, and N-cadherin) were significantly upregulated compared to parental cells, with the downregulation of E-cadherin as an EMT suppressor gene reflected in increased migration capacity. Moreover, increased expression of ABC transporter genes (ABCB1, ABCC1) was observed, correlating with enhanced drug resistance. The bioinformatic analysis highlighted pathways related to microRNAs in cancer, cells pluripotency, and proteoglycans. Methods of drug exposure take priority over spheroid formation, particularly due to their enhanced efficacy in stemness, EMT, and surface markers. This positions them as a promising protocol for establishing experimental models of CSCs.

Quantitative Proteomics and Phosphoproteomics Analysis of Patient-Derived Ovarian Cancer Stem Cells

High-grade serous ovarian carcinoma (HGSOC) is the deadliest gynecologic cancer. Key to the progression and ultimate lethality of this subtype is the intra-tumoral heterogeneity, which is defined as the coexistence of different cell types and populations within a single tumor. Among those, ovarian cancer stem cells (OCSCs) are a distinct subpopulation of tumor cells endowed with stem-like properties, which can survive current standard therapies, resulting in tumor recurrence. Here, we generated ex vivo primary OCSC-enriched three-dimensional (3D) spheres from 10 distinct treatment naive patient-derived adherent (2D) cultures. We used state-of-the-art quantitative mass spectrometry to characterize the molecular events associated with OCSCs by analyzing their proteome and phosphoproteome. Our data revealed a stemness-related protein signature, shared within a heterogeneous patient cohort, which correlates with chemo-refractoriness in a clinical proteomics dataset. Moreover, we identified targetable deregulated kinases and aberrant PDGF receptor activation in OCSCs. Pharmacological inhibition of PDGFR in adherent OC cells reduced the stemness potential, measured by sphere formation assay. Overall, we provide a valuable resource to identify new OCSC markers and putative targets for OCSC-directed therapies.

Aryl Hydrocarbon Receptor (AHR) Suppresses Arsenic (As3+)-Induced Malignant Transformation by Antagonizing TOX Expression

Environmental arsenic (As³⁺) exposure poses a significant public health concern due to its carcinogenic potential. Our previous research suggests that As³⁺-induced carcinogenesis is mediated by inhibition of the aryl hydrocarbon receptor (AHR). However, the precise role of AHR in As³⁺-induced malignant transformation as well as cancer stem-like cell (CSC) formation, along with its underlying mechanisms, remains unclear. In this study, we used BEAS-2B cells with CRISPR-Cas9 gene editing, RNA sequencing, and immunoprecipitation to examine AHR's role in As³⁺-induced CSC development. Our findings reveal that AHR suppresses CSC formation triggered by low-dose As³⁺ (0.5 μM) via transcriptional repression of TOX, a high mobility group box DNA binding protein that play a critical role in T cell exhaustion within tumor immunology. TOX knockdown inhibited CSC formation, while its overexpression enhanced cMYC, a CSC-associated transcription factor. TOX interactome analysis identified associations with proteins such as KCTD10, TRIM21, HMGA1, FLOT1, and FLOT2, which may regulate TOX's stability and activity. Enrichment analyses highlighted their involvement in cancer-related pathways, supporting the role of TOX in promoting CSC formation during As³⁺-induced carcinogenesis. Notably, this study identifies TOX as an oncogenic factor in non-immunological contexts and underscores AHR's tumor-suppressive function through TOX repression, offering novel insights into the mechanisms underlying As³⁺-induced carcinogenesis.

Role of octamer transcription factor 4 in proliferation, migration, drug sensitivity, and stemness maintenance of pancreatic cancer cells

BACKGROUND

Pancreatic cancer (PC) is one of the most aggressive malignancies characterized by rapid progression and poor prognosis. The involvement of cancer stem cells (CSCs) and Octamer transcription factor 4 (OCT4) in PC pathobiology is being increasingly recognized.

AIM

To investigate the role of OCT4 in pancreatic CSCs and its effect on PC cell proliferation, migration, drug sensitivity, and stemness maintenance.

METHODS

We analyzed OCT4 and CD133 expression in PC tissues and cell lines. BxPC-3 cells were used to assess the effects of OCT4 modulation on cellular behavior. Proliferation, migration, and stemness of BxPC-3 cells were evaluated, and the PI3K/AKT/mTOR pathway was examined to gain mechanistic insights.

RESULTS

OCT4 and CD133 were significantly overexpressed in PC tissues. OCT4 modulation altered BxPC-3 cell proliferation, invasion, and stemness, with OCT4 overexpression (OV-OCT4) enhancing these properties and OCT4 interference decreasing them. OV-OCT4 activated the PI3K/AKT/mTOR pathway, which correlated with an increase in PC stem cells (PCSC).

CONCLUSION

OCT4 plays a crucial role in PCSCs by influencing the aggressiveness and drug resistance of PC cells, thus presenting itself as a potential therapeutic target.

Tumor microenvironment: recent advances in understanding and its role in modulating cancer therapies

Tumor microenvironment (TME) denotes the non-cancerous cells and components presented in the tumor, including molecules produced and released by them. Interactions between cancer cells, immune cells, stromal cells, and the extracellular matrix within the TME create a dynamic ecosystem that can either promote or hinder tumor growth and spread. The TME plays a pivotal role in either promoting or inhibiting tumor growth and dissemination, making it a critical factor to consider in the development of effective cancer therapies. Understanding the intricate interplay within the TME is crucial for devising effective cancer therapies. Combination therapies involving inhibitors of immune checkpoint blockade (ICB), and/or chemotherapy now offer new approaches for cancer therapy. However, it remains uncertain how to best utilize these strategies in the context of the complex tumor microenvironment. Oncogene-driven changes in tumor cell metabolism can impact the TME to limit immune responses and present barriers to cancer therapy. Cellular and acellular components in tumor microenvironment can reprogram tumor initiation, growth, invasion, metastasis, and response to therapies. Components in the TME can reprogram tumor behavior and influence responses to treatments, facilitating immune evasion, nutrient deprivation, and therapeutic resistance. Moreover, the TME can influence angiogenesis, promoting the formation of blood vessels that sustain tumor growth. Notably, the TME facilitates immune evasion, establishes a nutrient-deprived milieu, and induces therapeutic resistance, hindering treatment efficacy. A paradigm shift from a cancer-centric model to a TME-centric one has revolutionized cancer research and treatment. However, effectively targeting specific cells or pathways within the TME remains a challenge, as the complexity of the TME poses hurdles in designing precise and effective therapies. This review highlights challenges in targeting the tumor microenvironment to achieve therapeutic efficacy; explore new approaches and technologies to better decipher the tumor microenvironment; and discuss strategies to intervene in the tumor microenvironment and maximize therapeutic benefits.

DOT1L Mediates Stem Cell Maintenance and Represents a Therapeutic Vulnerability in Cancer

Tumor-initiating cancer stem cells (CSC) pose a challenge in human malignancies as they are largely treatment resistant and can seed local recurrence and metastasis. Epigenetic mechanisms governing cell fate decisions in embryonic and adult stem cells are deregulated in CSCs. This review focuses on the methyltransferase disruptor of telomeric silencing protein 1-like (DOT1L), which methylates histone H3 lysine 79 and is a key epigenetic regulator governing embryonic organogenesis and adult tissue stem cell maintenance. DOT1L is overexpressed in many human malignancies, and dysregulated histone H3 lysine 79 methylation is pathogenic in acute myeloid leukemia and several solid tumors. DOT1L regulates core stem cell genes governing CSC self-renewal, tumorigenesis, and multidrug resistance. Recent work has situated DOT1L as an attractive stem cell target in cancer. These reports showed that DOT1L is overexpressed and its protein activated specifically in malignant stem cells compared with bulk tumor cells, making them vulnerable to DOT1L inhibition in vitro and in vivo. Although early DOT1L inhibitor clinical trials were limited by inadequate drug bioavailability, accumulating preclinical data indicate that DOT1L critically regulates CSC self-renewal and might be more effective when given with other anticancer therapies. The appropriate combinations of DOT1L inhibitors with other agents and the sequence and timing of drug delivery for maximum efficacy warrant further investigation.

Circular RNAs in cancer stem cells: Insights into their roles and mechanisms (Review)

Cancer stem cells (CSCs) represent a small, yet pivotal subpopulation of tumor cells that play significant roles in tumor initiation, progression and therapeutic resistance. Circular RNAs (circRNAs) are a distinct class of RNAs characterized by their closed‑loop structures, lacking 5' to 3'ends. There is growing evidence that circRNAs are integral to the development and regulation of CSCs. Aberrant expression of circRNAs in CSCs can contribute to oncogenic properties and drug resistance. Specifically, oncogenic circRNAs modulate CSC behavior via key signaling pathways, thereby promoting CSC self‑renewal and maintenance, as well as tumor progression. This review summarizes the latest research on the functional roles and regulatory mechanisms of circRNAs in CSC behavior and discusses potential applications and challenges of targeting circRNAs in CSCs. Understanding the intricate interactions between circRNAs and CSCs may lead to novel therapeutic strategies that effectively combat treatment resistance and improve patient outcomes.

Loss of TNFRSF21 induces cisplatin sensitivity in lung adenocarcinoma

Background

Despite the identification of numerous therapeutic targets in lung cancer, achieving significant efficacy has been challenging. TNFRSF21 plays an important role in various cancers. We investigated the function of TNFRSF21 in lung adenocarcinoma (LUAD).

Methods

The prognostic value of TNFRSF21 expression in lung cancer was evaluated by the GEPIA and Kaplan-Meier Plotter databases. Lung cancer cell viability was assessed by the CCK8 assay. TNFRSF21 expression patterns in lung cancer tissues and cells were examined using RT-PCR assay. Tumor sphere growth was evaluated through tumor sphere formation assays. MtROS contents in lung cancer cells were observed through MitoSOX fluorescent assays.

Result

TNFRSF21 was up-regulated in LUAD patients. TNFRSF21 induction was particularly notable in LUAD, especially in cancerous cells (A549, H1299, H460, and SPC-A1), compared to BEAS-2B cells. Additionally, TNFRSF21 was increased in cisplatin (DDP)-resistant LUAD cells. Loss of TNFRSF21 significantly inhibited LUAD cell growth. It was observed that forced expression of TNFRSF21 contributed to tumor cell proliferation and DDP resistance. The production of ROS was found to participate in the inhibitory effects on lung cancer stem cells (CSCs), with decreased TNFRSF21 restraining ROS contents. Collectively, these findings reveal that the downregulation of TNFRSF21 promotes ROS contents to restrain the lung CSC-like characteristics via modulation of CD44 and CD133.

Conclusions

In conclusion, TNFRSF21 may act as a novel target for lung cancer chemotherapy, particularly for eradicating lung CSCs.

Bioinformatics tools and experimental analysis combination for production of specific scFv against CD133

Prominin-1, or CD133, is a membrane-bound pentaspan protein that has been utilized recently to identify cancer stem cells (CSCs) in a variety of carcinomas. Today, bioinformatics offers a potent tool for studying the structural and functional relationships of fusion proteins. A structure-activity relationship model based on physicochemical characteristics, biological functions of single-chain antibodies, and molecular conformation can be developed by the integration of biomolecular computer models with biological experiments. In the present study, a mice library of single-chain variable fragment (scFv) antibodies was developed by mRNA extracted from mice immunized for the efficient and specific identification of the N-terminal domain of recombinant CD133 (D-EC1). First, a part of sequences of the scFvs library were cloned in the T.vector and sequenced. Then, bioinformatics was used to select the scFvs with high affinity by molecular dynamics simulations and docking. Based on bioinformatics analysis, three scFvs were cloned and expressed. Finally, the ability of the selected scFv was confirmed with the indirect enzyme-linked immunosorbent assay (ELISA) and immunocytochemistry (ICC). ELISA data showed that scFv3 had a greater affinity for the N-terminal of recombinant CD133, and it was selected for the immunocytochemistry (ICC) analysis. The immunocytochemistry experiments confirmed that the obtained scFv could bind to the CD133-expressing HT-29 cells. Our results suggest that using bioinformatics tools could be applied as a new, rapid, and valid method for the design and development of antibodies with improved properties. The selected scFv may be successfully applied in scFv-based diagnostics and therapeutics.

CPT1A-mediated MFF succinylation promotes stemness maintenance in ovarian cancer stem cells

Cancer stem cells (CSCs) play crucial roles in cancer progression, immune evasion, drug resistance, and recurrence. Understanding the mechanisms behind CSCs generation and stemness maintenance is vital for early cancer diagnosis and treatment. Here, we unveil that carnitine palmitoyltransferase 1A (CPT1A) is highly expressed in ovarian cancer stem cells (OCSCs) and is essential for maintaining stemness by regulating lipid desaturation. Studies confirmed that CPT1A enhances SREBP1 activation, upregulating SCD1 expression, and promoting lipid desaturation in OCSCs. Mechanistic studies reveal that CPT1A promotes succinylation of mitochondrial fission factor (MFF) through its lysine succinyltransferase (LSTase) activity, crucial for mitochondria-associated membranes formation and SREBP1 activation. Inhibiting CPT1A's LSTase activity with Glyburide reduces OCSCs' stemness and enhances cisplatin's anti-tumor effects against ovarian cancer in vitro and in vivo. Together, our studies highlight the significance of CPT1A's LSTase activity in maintaining OCSCs' stemness, offering potential targets and therapeutic strategies for ovarian cancer treatment.

Adiponectin Influences the Behavior of Stem Cells in Hormone-Resistant Breast Cancer

In the breast tumor microenvironment (TME), adipocytes exert a selective pressure on the behavior of breast cancer stem cells (BCSCs), which are involved in endocrine therapy resistance. In obesity, adipocytes secrete reduced levels of adiponectin, which promotes the growth and progression of ERα-positive breast cancer (BC). Here, we examined how low adiponectin levels affect the enrichment of the BCSC subpopulation and the mechanisms contributing to the maintenance of endocrine therapy resistance in BC. Flow cytometry, qRT-PCR, and Western blotting analysis were performed to assess stemness, the cell cycle, and apoptosis markers in MCF-7 wild-type (WT) and tamoxifen-resistant (TR) mammospheres. nLC-MS/MS was employed to profile and compare the proteome of BCSCs. Differentially expressed proteins were intersected with data from the MetacoreTM dataset. Our study demonstrated that adiponectin increased the percentage of CD44+/CD24-/ALDH1+ stem-like cells in TR MCF-7 mammospheres. Specifically, adiponectin contributed to the maintenance of BCSC bulk in TR MCF-7 cells through a slow cycling rate, supported by decreased levels of Cyclin D1 and Ki67 and increased p21 and p27 expression, and through escape from apoptosis, sustained by reduced ROS production and preserved maintenance of mitochondrial membrane potential. Our results provide new insights into the contribution of adiponectin to poor ERα-positive BC outcomes. Deeply understanding adiponectin's role in stemness may disclose novel therapeutic approaches to treat hormone-resistant obese BC patients.

Enhanced Oxidative Phosphorylation Driven by TACO1 Mitochondrial Translocation Promotes Stemness and Cisplatin Resistance in Bladder Cancer

Chemoresistance poses a critical obstacle in bladder cancer (BCa) treatment, and effective interventions are currently limited. Elevated oxidative phosphorylation (OXPHOS) has been linked to cancer stemness, a determinant of chemoresistance. However, the mechanisms underlying increased OXPHOS during cancer cell chemoresistance remain unclear. This study revealed that the mitochondrial translational activator of cytochrome oxidase subunit 1 (TACO1) is linked to stemness and cisplatin resistance in BCa cells. Mechanistically, mitochondrial TACO1 enhances the translation of the mitochondrial cytochrome c oxidase I (MTCO1), promoting mitochondrial reactive oxygen species (mtROS) by upregulating OXPHOS, consequently driving cancer stemness and cisplatin resistance. Intriguingly, the mitochondrial translocation of TACO1 is mediated by the heat shock protein 90 β (HSP90β), a process that requires circFOXK2 as a scaffold for the TACO1-HSP90β interaction. The mutations at the binding sites of TACO1-circFOXK2-HSP90β disturb the ternary complex and inhibit cancer stemness and cisplatin resistance in BCa cells by suppressing the MTCO1/OXPHOS/mtROS axis. Clinically, BCa patients with increased mitochondrial TACO1 expression respond poorly to cisplatin treatment. This study elucidates the mechanisms by which TACO1 promotes BCa stemness and cisplatin resistance, providing a potential target for mitigating cisplatin resistance for BCa and a biomarker for predicting cisplatin response.

Deciphering the Role of Cancer Stem Cells: Drivers of Tumor Evolution, Therapeutic Resistance, and Precision Medicine Strategies

Cancer stem cells (CSCs) play a central role in tumor progression, recurrence, and resistance to conventional therapies, making them a critical focus in oncology research. This review provides a comprehensive analysis of CSC biology, emphasizing their self-renewal, differentiation, and dynamic interactions with the tumor microenvironment (TME). Key signaling pathways, including Wnt, Notch, and Hedgehog, are discussed in detail to highlight their potential as therapeutic targets. Current methodologies for isolating CSCs are critically examined, addressing their advantages and limitations in advancing precision medicine. Emerging technologies, such as CRISPR/Cas9 and single-cell sequencing, are explored for their transformative potential in unraveling CSC heterogeneity and informing therapeutic strategies. The review also underscores the pivotal role of the TME in supporting CSC survival, promoting metastasis, and contributing to therapeutic resistance. Challenges arising from CSC-driven tumor heterogeneity and dormancy are analyzed, along with strategies to mitigate these barriers, including novel therapeutics and targeted approaches. Ethical considerations and the integration of artificial intelligence in designing CSC-specific therapies are discussed as essential elements of future research. The manuscript advocates for a multi-disciplinary approach that combines innovative technologies, advanced therapeutics, and collaborative research to address the complexities of CSCs. By bridging existing gaps in knowledge and fostering advancements in personalized medicine, this review aims to guide the development of more effective cancer treatment strategies, ultimately improving patient outcomes.

Comprehensive bioinformatics analysis of the prognostic value and immune infiltration of CAPN2 in pancreatic adenocarcinoma

BACKGROUND

Pancreatic adenocarcinoma (PAAD) is a highly aggressive cancer with a poor prognosis, highlighting an urgent requirement for effective biomarkers for its early diagnosis and prognosis prediction. CAPN2, a calcium-dependent protease, has been implicated in various cancers, but its role in PAAD remains unclear.

METHODS

In this study, we utilized multiple bioinformatics methods, including differential expression, survival, correlation, and enrichment analyses, to investigate the prognostic value of CAPN2 in PAAD using data from the TCGA and GEO databases. Additionally, the correlation between CAPN2 expression and the tumor microenvironment (TME), immunotherapy potential, and drug sensitivity was also explored.

RESULTS

CAPN2 was upregulated in PAAD tissues and was correlated with higher tumor grade. And high expression of CAPN2 was significantly associated with reduced overall survival, establishing it as an independent prognostic biomarker for PAAD. Enrichment analysis implicated that CAPN2 was involved in multiple biological processes and pathways associated with tumor immunity. Furthermore, CAPN2 expression had a negative correlation with immune cell infiltration and a positive association with tumor mutational burden, which may have potential implications for immunotherapy strategies.

CONCLUSIONS

CAPN2 is a promising biomarker for PAAD prognosis and a potential therapeutic target. Its association with the TME and immunotherapy response highlights its importance in PAAD progression and patient outcomes, warranting further investigation into its role and potential clinical applications.

Clinical implications of epithelial-to-mesenchymal transition in cancers which potentially spread to peritoneum

Epithelial-to-mesenchymal transition (EMT) is a biological process by which epithelial cells increase their motility and acquire invasive capacity. It represents a crucial driver of cancer metastasis and peritoneal dissemination. EMT plasticity, with cells exhibiting hybrid epithelial/mesenchymal states, and its reverse process, mesenchymal-to-epithelial transition (MET), allows them to adapt to different microenvironments and evade therapeutic intervention. Resistance to conventional treatments, including chemotherapy, is a major problem. Therapies targeting EMT may inhibit tumour cell migration and invasion, while affecting normal cells and repair mechanisms, resulting in potential side effects. This paper addresses the question of the impact of EMT status on cancers with potential spread to the peritoneum, which has remained unclear in literature. Relevant studies were selected from 2000 to 2024. Three macrosections were analysed: (i) pathological characteristics, (ii) surgical implications and (iii) oncological therapies. The focus was on survival and peritoneal recurrence time in patients who underwent surgical treatment.

Tumor microenvironment targeted nano-drug delivery systems for multidrug resistant tumor therapy

In recent years, nano-drug delivery systems (Nano-DDS) that target the tumor microenvironment (TME) to overcome multidrug resistance (MDR) have become a research hotspot in the field of cancer therapy. By precisely targeting the TME and regulating its unique pathological features, such as hypoxia, weakly acidic pH, and abnormally expressed proteins, etc., these Nano-DDS enable effective delivery of therapeutic agents and reversal of MDR. This scientific research community is increasing its investment in the development of diversified systems and exploring their anti-drug resistance potential. Therefore, it is particularly important to conduct a comprehensive review of the research progress of TME-targeted Nano-DDS in recent years. After a brief introduction of TME and tumor MDR, the design principle and structure of liposomes, polymer micelles and inorganic nanocarriers are focused on, and their characteristics as TME-targeted nanocarriers are described. It also demonstrates how these systems break through the cancer MDR treatment through various targeting mechanisms, discusses their synthetic innovation, research results and resistance overcoming mechanisms. The review was concluded with deliberations on the key challenges and future outlooks of targeting TME Nano-DDS in cancer therapy.

Kinase library screening identifies IGF-1R as an oncogenic vulnerability in intrahepatic cholangiocarcinoma stem-like cells

BACKGROUND

Intrahepatic cholangiocarcinoma (iCCA) is a highly aggressive cancer of the peripheral bile ducts and is recognized by the abundance of cancer stem-like cells (CSCs) within the tumor mass. While CSC markers in iCCA are well-defined, the molecular vulnerabilities of this subpopulation remain elusive.

METHODS

The 96-well, three dimensional (3D) tumorsphere culture was adapted from a well-established CSC model, validated for CSC markers through gene expression analysis. Kinase library screening was then conducted to reveal potential oncogenic vulnerable pathways. RNA interference was utilized to stably silence the candidate gene in three iCCA cell lines and its impact on iCCA cell proliferation and tumorsphere formation efficiency (TFE) was evaluated.

RESULTS

Kinase inhibitor library screening identified the top 50 kinase inhibitors crucial for tumorsphere viability, with 11 inhibitors targeting the IGF-1R/PI3K/AKT axis. Further dose-dependent analysis of the top 'hit' inhibitors confirmed IGF-1R as the candidate molecule. Upon stably silencing of IGF-1R, all three iCCA cell lines exhibited decreased AKT activation, impeded proliferation and reduced TFE, indicating a decline in CSC subpopulations.

CONCLUSIONS

IGF-1R plays a critical role in maintaining iCCA-stem like cell populations.

GENERAL SIGNIFICANCE

Our data highlight the potential utility of IGF-1R as a prognostic marker of iCCA and a therapeutic target for eliminating its CSC subpopulation.

Targeted Drug Nanodelivery and Immunotherapy for Combating Tumor Resistance

Chemotherapy resistance is a common cause of tumor treatment failure. Various molecular responses, such as increased expression of efflux transporter proteins, including Pglycoprotein (P-gp), changes in the tumor microenvironment (TME), the role of platelets, and the effects of cancer stem cells (CSCs), can lead to drug resistance. Through extensive research on the mechanisms of drug resistance, more effective anti-resistance drugs and therapeutic approaches are being developed. This review explores drug resistance mechanisms and summarizes relevant anti-resistance drugs. In addition, due to the therapeutic limitations of the aforementioned treatments, new advances in nanocarrier-based combination immunotherapy to address the challenge of drug resistance have been described. Nanocarriers combined with immunotherapy can not only target tumor sites for targeted drug release but also modulate the autoimmune system and enhance immune efficacy, thereby overcoming tumor drug resistance. This review suggests new strategies for overcoming tumor drug resistance and is expected to inform tumor treatment and prognosis.

Coptisine acts as a nucleolus fluorescent probe in vitro

Coptisine (COP) is a natural protoberberine isoquinoline alkaloid that is isolated from Coptis chinensis and exhibits a variety of pharmacological activities, such as the inhibition of tumor growth, bacterial infection, inflammation and oxidative stress. In this study, COP penetrated and produced fluorescent signals in living tumor cell lines, primary MEF cells and polyformaldehyde-fixed cells. The fluorescent signal was detected at a wavelength of 488 nm. The fluorescent signal of COP was observed predominantly in the nucleoli and colocalized with nucleolus fibrillarin and B23. The fluorescence intensity of COP was associated with tumor malignancy. Compared with cells with high fluorescent signals, cells with low fluorescent signals were highly malignant. Taken together, these data suggest that COP can function as a nucleolus probe and a probe candidate for distinguishing tumor cell malignancy.

Polyanhydride Copolymer-Based Niclosamide Nanoparticles for Inhibiting Triple-Negative Breast Cancer: Metabolic Responses and Synergism with Paclitaxel

The heterogeneity of tumors and the lack of effective therapies have resulted in triple-negative breast cancer (TNBC) exhibiting the least favorable outcomes among breast cancer subtypes. TNBC is characterized by its aggressive nature, often leading to high rates of relapse, metastasis, and mortality. Niclosamide (Nic), an Food and Drug Administration-approved anthelmintic drug, has been repurposed for cancer treatment; however, its application for TNBC is hindered by significant challenges, including strong hydrophobicity, poor aqueous solubility, and low bioavailability. This study aimed to develop Nic nanoparticles (Nic NPs) using biodegradable and biocompatible polyanhydride copolymers to enhance Nic's bioavailability and therapeutic efficacy. Nic NPs effectively inhibited migration, proliferation, and clonogenicity in both murine and human TNBC cells, inducing apoptosis and suppressing STAT3 signaling. For the first time, we utilized Raman spectroscopy and Seahorse extracellular flux assays to demonstrate the metabolic responses of TNBC cells to Nic NPs, revealing significant metabolic alterations, including the inhibition of mitochondrial respiration and glycolysis. Additionally, this study is the first to explore the combination therapy of repurposed Nic with the approved chemotherapeutic agent paclitaxel in the 4T1 TNBC immunocompetent mouse model. The combination of Nic NPs and paclitaxel significantly reduced tumor growth without adversely affecting the body weight of tumor-bearing mice. In summary, these findings suggest that Nic NPs could serve as a promising component in combination therapies for the effective treatment of TNBC.

RNA binding protein ZCCHC24 promotes tumorigenicity in triple-negative breast cancer

Triple-negative breast cancer (TNBC) lacks the expression of hormone and HER2 receptors and is highly malignant with no effective therapeutic targets. In TNBC, the cancer stem-like cell (CSC) population is considered to be the main cause of resistance to treatment. Thus, the therapeutic targeting of this population could substantially improve patient survival. Here, we identify the RNA-binding protein ZCCHC24 as enriched in the mesenchymal-like TNBC population. ZCCHC24 promotes the expression of a set of genes related to tumorigenicity and treatment resistance by directly binding to the cis-element "UGUWHWWA" in their mRNAs, thereby stabilizing them. One of the ZCCHC24 targets, ZEB1, is a transcription factor that promotes the expression of cancer stemness genes and reciprocally induces ZCCHC24 expression. ZCCHC24 knockdown by siRNAs shows a therapeutic effect and reduces the mesenchymal-like cell population in TNBC patient-derived xenografts. ZCCHC24 knockdown also has additive effects with the BET inhibitor JQ1 in suppressing tumor growth in TNBC patient-derived xenografts.

Oncogenic fusion of CD63-BCAR4 contributes cancer stem cell-like properties via ALDH1 activity

Gene fusions are common somatic alterations in cancers, and fusions with tumorigenic features have been identified as novel drivers of cancer and therapeutic targets. Few studies have determined whether the oncogenic ability of fusion genes is related to the induction of stemness in cells. Cancer stem cells (CSCs) are a subset of cells that contribute to cancer progression, metastasis, and recurrence, and are critical components of the aggressive features of cancer. Here, we investigated the CSC-like properties induced by CD63-BCAR4 fusion gene, previously reported as an oncogenic fusion, and its potential contribution for the enhanced metastasis as a notable characteristic of CD63-BCAR4. CD63-BCAR4 overexpression facilitates sphere formation in immortalized bronchial epithelial cells. The significantly enhanced sphere-forming activity observed in tumor-derived cells from xenografted mice of CD63-BCAR4 overexpressing cells was suppressed by silencing of BCAR4. RNA microarray analysis revealed that ALDH1A1 was upregulated in the BCAR4 fusion-overexpressing cells. Increased activity and expression of ALDH1A1 were observed in the spheres of CD63-BCAR4 overexpressing cells compared with those of the empty vector. CD133 and CD44 levels were also elevated in BCAR4 fusion-overexpressing cells. Increased NANOG, SOX2, and OCT-3/4 protein levels were observed in metastatic tumor cells derived from mice injected with CD63-BCAR4 overexpressing cells. Moreover, DEAB, an ALDH1A1 inhibitor, reduced the migration activity induced by CD63-BCAR4 as well as the sphere-forming activity. Our findings suggest that CD63-BCAR4 fusion induces CSC-like properties by upregulating ALDH1A1, which contributes to its metastatic features.

Precise Regulations at the Subcellular Level through Intracellular Polymerization, Assembly, and Transformation

A living cell is an intricate machine that creates subregions to operate cell functions effectively. Subcellular dysfunction has been identified as a potential druggable target for successful drug design and therapy. The treatments based on intracellular polymerization, self-assembly, or transformation offer various advantages, including enhanced blood circulation of monomers, long-term drug delivery pharmacokinetics, low drug resistance, and the ability to target deep tissues and organelles. In this review, we discuss the latest developments of intracellular synthesis applied to precisely control cellular functions. First, we discuss the design and applications of endogenous and exogenous stimuli-triggered intracellular polymerization, self-assembly, and dynamic morphology transformation of biomolecules at the subcellular level. Second, we highlight the benefits of these strategies applied in cancer diagnosis and treatment and modulating cellular states or cell metabolism of living systems. Finally, we conclude the recent progress in this field, discuss future perspectives, analyze the challenges of the intracellular functional reactions for regulation, and find future opportunities.

Standard chemotherapy impacts on in vitro cellular heterogeneity in spheroids enriched with cancer stem cells (CSCs) derived from triple-negative breast cancer cell line

Triple-negative breast cancer is a heterogeneous disease with high recurrence and mortality, linked to cancer stem cells (CSCs). Our study characterized distinct cell subpopulations and signaling pathways to explore chemoresistance. We observed cellular heterogeneity among and within the cells regarding phenotyping and drug response. In untreated BT-549 cells, we noted plasticity properties in both CD44+/CD24+/CD146+ hybrid cells and CD44-/CD24+/CD146+ epithelial cells, enabling phenotypic conversion into CD44+/CD24-/CD146- epithelial-mesenchymal transition (EMT)-like like breast CSCs (BCSCs). Additionally, non-BCSCs may give rise to ALDH+ epithelial-like BCSCs. Enriched BCSCs demonstrated the potential to differentiation into CD44-/CD24-/CD146- cells and exhibited self-renewal capabilities. Similar phenotypic plasticity was not observed in untreated Hs 578T and HMT-3522 S1 cells. BT-549 cells were more resistant to paclitaxel/PTX than to doxorubicin/DOX, a phenomenon potentially linked to the presence of CD24+ cells prior to treatment. Under the CSCs-enriched spheroids model, BT-549 demonstrated extreme resistance to DOX, likely due to the enrichment of BCSCs CD44+/CD24-/CD146- and the tumor cells CD44-/CD24-/CD146-. Additionally, DOX treatment induced the enrichment of plastic and chemoresistant cells, further exacerbating resistance mechanisms. BT-549 exhibited high heterogeneity, leading to significant alterations in cell subpopulations under BCSCs enrichment, demonstrating increased phenotypic plasticity during EMT. This phenomenon appears to play a major role in DOX resistance, as indicated by the presence of the refractory cells CD44+/CD24-/CD146- BCSCs EMT-like, CD44-/CD24-/CD146- tumor cells, and elevated STAT3 expression. Gene expression data from BT-549 CSCs-enriched spheroids suggests that ferroptosis may be occurring via autophagic regulation triggered by RAB7A, highlighting this gene as a potential therapeutic target.

SLC4A11 mediates ammonia import and promotes cancer stemness in hepatocellular carcinoma

End-stage liver disease is marked by portal hypertension, systemic elevations in ammonia, and development of hepatocellular carcinoma (HCC). While these clinical consequences of cirrhosis are well described, it remains poorly understood whether hepatic insufficiency and the accompanying elevations in ammonia contribute to HCC carcinogenesis. Using preclinical models, we discovered that ammonia entered the cell through the transporter SLC4A11 and served as a nitrogen source for amino acid and nucleotide biosynthesis. Elevated ammonia promoted cancer stem cell properties in vitro and tumor initiation in vivo. Enhancing ammonia clearance reduced HCC stemness and tumor growth. In patients, elevations in serum ammonia were associated with an increased incidence of HCC. Taken together, this study forms the foundation for clinical investigations using ammonia-lowering agents as potential therapies to mitigate HCC incidence and aggressiveness.

Sequential Responsive Multifunctional Nanomicelle Effectuates Collective Elimination of Breast Cancer and Cancer Stem Cells

Designing effective multifunctional nanodrugs to achieve multimodal treatment of tumors is an ideal choice to improve the poor clinical outcomes of current anti-tumor therapies. Here, a multifunctional nanomicelle DC@H loaded with sarcoma kinase and cyclooxygenase-2 protein dual target inhibitor DI02 is designed and prepared, which is sequentially catalyzed by carboxylesterase and glutathione for reduction, and strengthens the inhibition of cancer stem cell (CSC) related protein STAT3. The camptothecin carried by the DC@H ensures the effectiveness of chemotherapy. Ultimately, DC@H precisely releases and achieves effective inhibition of xenograft tumors based on the combination of chemotherapy, targeted therapy, and chemodynamic therapy, with a tumor inhibition rate of up to 90.89% in BALB/c nude mice. Research on lung metastasis proves that the CSC inhibitory characteristic of DC@H is a direct cause of the elimination of tumor metastatic nodules. There is no doubt that the multifunctional nano drug DC@H, which effectuates the collective elimination of breast cancer and cancer stem cells, provides a promising direction for achieving complete tumor cure in clinical practice.

Application of hydrogels for targeting cancer stem cells in cancer treatment

Cancer stem cells (CSCs) are a major hindrance to clinical cancer treatment. Owing to their high tumorigenic and metastatic potential, CSCs are vital in malignant tumor initiation, growth, metastasis, and therapeutic resistance, leading to tumorigenesis and recurrence. Compared with normal tumor cells, CSCs express high levels of surface markers (CD44, CD90, CD133, etc.) and activate specific signaling pathways (Wnt/β-catenin, Notch, and Hedgehog). Although Current drug delivery systems (DDS) precisely target CSCs, the heterogeneity and multidrug resistance of CSCs impede CSC isolation and screening. Conversely, hydrogel DDSs exhibit good biocompatibility and high drug delivery efficiency. Hydrogels are three-dimensional (3D) spatial structures for drug encapsulation that facilitate the controlled release of bioactive molecules. Hence, hydrogels can be loaded with drugs to precisely target CSCs. Their 3D structure can also culture non-CSCs and facilitate their transformation into CSCs. for identification and isolation. Given that their elastic modulus and stiffness characteristics reflect those of the cellular microenvironment, hydrogels can simulate extracellular matrix pathways and markers to regulate CSCs, disrupting the equilibrium between CSC and non-CSC transformation. This article reviews the CSC microenvironment, metabolism, signaling pathway, and surface markers. Additionally, we summarize the existing CSC targeting strategies and explore the application of hydrogels for CSC screening and treatment. Finally, we discuss potential advances in CSC research that may lead to curative measures for tumors through targeted and precise attacks on CSCs.

Medicinal plants as a potential resource for the discovery of novel structures towards cancer drug resistance treatment

Despite extensive research in chemotherapy, global cancer concerns persist, exacerbated by the challenge of drug resistance, which imposes economic and medical burdens. Natural compounds, particularly secondary metabolites from medicinal plants, present promising avenues for overcoming cancer drug resistance due to their diverse structures and essential pharmacological effects. This review provides a comprehensive exploration of cancer cell resistance mechanisms and target actions for reversing resistance and highlights the in vitro and in vivo efficacy of noteworthy alkaloids, flavonoids, and other compounds, emphasizing their potential as therapeutic agents. The molecular properties supporting ligand interactions are thoroughly examined, providing a robust theoretical foundation. The review concludes by discussing methods including quantitative structure-activity relationships and molecular docking, offering insights into screening potential candidates. Current trends in clinical treatment, contributing to a holistic understanding of the multifaceted approaches to address cancer drug resistance are also outlined.

RAB4A is a master regulator of cancer cell stemness upstream of NUMB-NOTCH signaling

Cancer stem cells (CSCs) are a group of specially programmed tumor cells that possess the characteristics of perpetual cell renewal, increased invasiveness, and often, drug resistance. Hence, eliminating CSCs is a major challenge for cancer treatment. Understanding the cellular programs that maintain CSCs, and identifying the critical regulators for such programs, are major undertakings in both basic and translational cancer research. Recently, we have reported that RAB4A is a major regulator of epithelial-to-mesenchymal transition (EMT) and it does so mainly through regulating the activation of RAC1 GTPase. In the current study, we have delineated a new signaling circuitry through which RAB4A transmits its control of cancer stemness. Using in vitro and in vivo studies, we show that RAB4A, as the upstream regulator, relays signal stepwise to NUMB, NOTCH1, RAC1, and then SOX2 to control the self-renewal property of multiple cancer cells of diverse tissue origins. Knockdown of NUMB, or overexpression of NICD (the active fragment NOTCH1) or SOX2, rescued the in vitro sphere-forming and in vivo tumor-forming abilities that were lost upon RAB4A knockdown. Furthermore, we discovered that the chain of control is mostly through transcriptional regulation at every step of the pathway. The discovery of the novel signaling axis of RAB4A-NUMB-NOTCH-SOX2 opens the path for further expansion of the signaling chain and for the identification of new regulators and interacting proteins important for CSC functions, which can be explored to develop new and effective therapies.

Advances in tumor microenvironment: Applications and challenges of 3D bioprinting

The tumor microenvironment (TME) assumes a pivotal role in the treatment of oncological diseases, given its intricate interplay of diverse cellular components and extracellular matrices. This dynamic ecosystem poses a serious challenge to traditional research methods in many ways, such as high research costs, inefficient translation, poor reproducibility, and low modeling success rates. These challenges require the search for more suitable research methods to accurately model the TME, and the emergence of 3D bioprinting technology is transformative and an important complement to these traditional methods to precisely control the distribution of cells, biomolecules, and matrix scaffolds within the TME. Leveraging digital design, the technology enables personalized studies with high precision, providing essential experimental flexibility. Serving as a critical bridge between in vitro and in vivo studies, 3D bioprinting facilitates the realistic 3D culturing of cancer cells. This comprehensive article delves into cutting-edge developments in 3D bioprinting, encompassing diverse methodologies, biomaterial choices, and various 3D tumor models. Exploration of current challenges, including limited biomaterial options, printing accuracy constraints, low reproducibility, and ethical considerations, contributes to a nuanced understanding. Despite these challenges, the technology holds immense potential for simulating tumor tissues, propelling personalized medicine, and constructing high-resolution organ models, marking a transformative trajectory in oncological research.

The pathogenic germline ETV4 P433L mutation identified in multiple primary lung cancer affect tumor stem-like property by Wnt/β-catenin pathway

The occurrence of multiple primary lung cancer (MPLC) has witnessed a significant surge in recent years within the Chinese population. MPLC is distinguished by its potential genetic susceptibility and notable genetic heterogeneity. Investigating the etiology of MPLC holds substantial clinical importance.The whole genome sequencing (WGS) and genome-wide linkage analysis were performed in a family affected by a dominant form of lung abnormalities. Specifically, five family members were diagnosed with MPLC, while nine members had pulmonary nodules and one normal member. To confirm the potential pathogenic germline mutations sites, Sanger sequencing was performed in an additional 162 MPLC family patients. Furthermore, molecular biology experiments were conducted to investigate the function and the mechanism of the identified pathogenic mutation site in lung cancer A549 and H322, both in vitro and in vivo. Linkage analysis revealed the presence of shared genomic regions among affected family members. Subsequent exome sequencing identified a deleterious variant within these linkage intervals, specifically a heterozygous mutation in ETS-oncogene transcription factors 4 (ETV4). This particular variant was found in affected family members at a rate of 13 out of 15 individuals. Furthermore, ETV4 P433L mutation could be detected in an additional MPLC family patients and mutation frequency was 3.7% (6 out of 162). The ETV4 P433L mutations site was introduced into lung cancer cell lines, resulting in altered migration and stem-like properties of the cancer cells. Further investigation revealed that the activation of the Wnt/β-catenin signaling pathway, which is associated with stemness, could be attributed to the presence of the ETV4 P433L mutation, suggesting its involvement in tumor promotion. A novel pathogenic germline mutation, ETV4 P433L, was identified in a dominant MPLC family, with a mutation rate of 3.7% among MPLC family patients. The ETV4 P433L mutation was found to impact the stem-like properties and migration of tumors through Wnt/β-catenin signaling pathway.

Targeting CERS6-AS1/FGFR1 axis as synthetic vulnerability to constrain stromal cells supported proliferation in Mantle cell lymphoma

The interaction between stromal and tumor cells in tumor microenvironment is a crucial factor in Mantle cell lymphoma (MCL) progression and therapy resistance. We have identified a long non-coding RNA, CERS6-AS1, upregulated in MCL and associated with poor overall survival. CERS6-AS1 expression was elevated in primary MCL within stromal microenvironment and in a subset of MCL cells adhered to stromal layer. These stromal-adhered MCL-subsets exhibited cancer stem cell signatures than suspension counterparts. Mechanistically, we found that downregulating CERS6-AS1 in MCL reduced Fibroblast Growth Factor Receptor-1 (FGFR1), expression attributed to loss of its interaction with RNA-binding protein nucleolin. In addition, using in-silico approach, we have discovered a direct interaction between nucleolin and 5'UTR of FGFR1, thereby regulating FGFR1 transcript stability. We discovered a positive association of CERS6-AS1 with cancer stem cell signatures, and Wnt signaling. Building on these, we explored potential therapeutic strategies where combining nucleolin-targeting agent with FGFR1 inhibition significantly contributed to reversing cancer stem cell signatures and abrogated primary MCL cell growth on stromal layer. These findings provide mechanistic insights into regulatory network involving CERS6-AS1, nucleolin, and FGFR1 axis-associated crosstalk between tumor cells and stromal cell interaction and highlights therapeutic potential of targeting a non-coding RNA in MCL.

A Multi-Omics Prognostic Model Capturing Tumor Stemness and the Immune Microenvironment in Clear Cell Renal Cell Carcinoma

Background: Cancer stem-like cells (CSCs), a distinct subset recognized for their stem cell-like abilities, are intimately linked to the resistance to radiotherapy, metastatic behaviors, and self-renewal capacities in tumors. Despite their relevance, the definitive traits and importance of CSCs in the realm of oncology are still not fully comprehended, particularly in the context of clear cell renal cell carcinoma (ccRCC). A comprehensive understanding of these CSCs' properties in relation to stemness, and their impact on the efficacy of treatment and resistance to medication, is of paramount importance. Methods: In a meticulous research effort, we have identified new molecular categories designated as CRCS1 and CRCS2 through the application of an unsupervised clustering algorithm. The analysis of these subtypes included a comprehensive examination of the tumor immune environment, patterns of metabolic activity, progression of the disease, and its response to immunotherapy. In addition, we have delved into understanding these subtypes' distinctive clinical presentations, the landscape of their genomic alterations, and the likelihood of their response to various pharmacological interventions. Proceeding from these insights, prognostic models were developed that could potentially forecast the outcomes for patients with ccRCC, as well as inform strategies for the surveillance of recurrence after treatment and the handling of drug-resistant scenarios. Results: Compared with CRCS1, CRCS2 patients had a lower clinical stage/grading and a better prognosis. The CRCS2 subtype was in a hypoxic state and was characterized by suppression and exclusion of immune function, which was sensitive to gefitinib, erlotinib, and saracatinib. The constructed prognostic risk model performed well in both training and validation cohorts, helping to identify patients who may benefit from specific treatments or who are at risk of recurrence and drug resistance. A novel therapeutic target, SAA2, regulating neutrophil and fibroblast infiltration, and, thus promoting ccRCC progression, was identified. Conclusions: Our findings highlight the key role of CSCs in shaping the ccRCC tumor microenvironment, crucial for therapy research and clinical guidance. Recognizing tumor stemness helps to predict treatment efficacy, recurrence, and drug resistance, informing treatment strategies and enhancing ccRCC patient outcomes.

Trapped in Cells: A Selective Accumulation Approach for Type-I Photodynamic Ablation of Cancer Stem-like Cells

Aldehyde dehydrogenase (ALDH) is an enzyme responsible for converting aldehyde functional groups into carboxylate metabolites. Elevated ALDH activity is a characteristic feature of cancer stem-like cells (CSCs). As a novel approach to target the CSC trait of overexpressing ALDH, we aimed to utilize ALDH activity for the selective accumulation of a photosensitizer in ALDHHigh CSCs. A novel ALDH substrate photosensitizer, SCHO, with thionylated coumarin and N-ethyl-4-(aminomethyl)benzaldehyde was developed to achieve this goal. Our study demonstrated the efficient metabolism of the aldehyde unit of SCHO into carboxylate, leading to its accumulation in ALDHHigh MDA-MB-231 cells. Importantly, we established the selectivity of SCHO as an ALDHHigh cell photosensitizer as it is not a substrate for ABC transporters. SCHO-based photodynamic therapy triggers apoptosis and pyroptosis in MDA-MB-231 cells and further reduces the characteristics of CSCs. Our study presents a novel strategy to target CSCs by exploiting their cellular metabolism to enhance photosensitizer accumulation, highlighting the potential of photodynamic therapy as a powerful tool for eliminating ALDHHigh CSCs.

Investigation of tumour environments through advancements in microtechnology and nanotechnology

Cancer has a significant negative social and economic impact on both developed and developing countries. As a result, understanding the onset and progression of cancer is critical for developing therapies that can improve the well-being and health of individuals with cancer. With time, study has revealed, the tumor microenvironment has great influence on this process. Micro and nanoscale engineering techniques can be used to study the tumor microenvironment. Nanoscale and Microscale engineering use Novel technologies and designs with small dimensions to recreate the TME. Knowing how cancer cells interact with one another can help researchers develop therapeutic approaches that anticipate and counteract cancer cells' techniques for evading detection and fighting anti-cancer treatments, such as microfabrication techniques, microfluidic devices, nanosensors, and nanodevices used to study or recreate the tumor microenvironment. Nevertheless, a complicated action just like the growth and in cancer advancement, and their intensive association along the environment around it that has to be studied in more detail.

Methods for Overcoming Chemoresistance in Head and Neck Squamous Cell Carcinoma: Keeping the Focus on Cancer Stem Cells, a Systematic Review

According to the "cancer stem cell" (CSCs) theory, tumors are a diverse and expanding group of malignant cells that originate from a small number of CSCs. Despite treatment, these cells can still become active and proliferate, which can result in distant metastasis and local recurrences. A new paradigm in cancer treatment involves targeting both CSCs and the cancer cells in a tumor. This review aims to examine the literature on methods published to overcome chemoresistance due to the presence of CSCs in head and neck cancers. The review was registered with PROSPERO (ID# CRD42024512809). After Pub Med, Scopus, and WoS database searches, 31 relevant articles on oral squamous cell carcinoma (OSCC) were selected. Compounds that increased chemosensitivity by targeting CSCs in head and neck squamous cell carcinoma (HNSCC) were divided into (1) natural products, (2) adjuvant molecules to traditional chemotherapy, and (3) CSCs targeting patient-specific fresh biopsies for functional precision medicine.

Unlocking the Therapeutic Potential of Oral Cancer Stem Cell-Derived Exosomes

Oral cancer (OC) presents a significant global health burden with rising incidence rates. Despite advancements in diagnosis and treatments, the survival rate for OC patients, particularly those with advanced or recurrent disease, remains low at approximately 20%. This poor prognosis is often due to a small population of cancer stem cells (CSCs) that are capable of self-renewal and immune evasion, playing pivotal roles in proliferation, tumor initiation, progression, metastasis, and therapy resistance. Exosomes, which are nano-sized extracellular vesicles (EVs), have emerged as crucial mediators of cell-to-cell communication within the tumor microenvironment (TME). These vesicles carry diverse molecules such as DNA, RNA, proteins, lipids, and metabolites, influencing various cellular processes. Emerging evidence suggests that CSC-derived EVs significantly promote tumor progression and metastasis and maintain the balance between CSCs and non-CSCs, which is vital for intracellular communication within the TME of oral cancer. Recent reports indicate that oral cancer stem cell-derived EVs (OCSC-EVs) influence stemness, immune evasion, metastasis, angiogenesis, tumor reoccurrence, and drug resistance. Understanding OCSC-EVs could significantly improve oral cancer diagnosis, prognosis, and therapy. In this mini-review, we explore OCSC-derived exosomes in oral cancer, examining their potential as diagnostic and prognostic biomarkers that reflect CSC characteristics, and delve into their therapeutic implications, emphasizing their roles in tumor progression and therapy resistance. However, despite their promising potential, several challenges remain, including the need to standardize isolation and characterization methods and to elucidate exosome-mediated mechanisms. Thus, a comprehensive understanding of OCSC-EVs could pave the way for innovative therapeutic strategies that have the potential to improve clinical outcomes for OC patients.

GDF6 in gastric cancer upregulated by helicobacter pylori induces epithelial-mesenchymal translation via the TGF-β/SMAD3 signaling pathway

OBJECTIVE

To investigate the association between Helicobacter pylori infection and GDF6 expression in gastric cancer patients, and to determine its influence on prognosis and resistance to capecitabine.

METHODS

Tumor and adjacent non-tumor tissues were collected from 148 gastric cancer patients who underwent surgery in our department from October 2019 to June 2022. Of these patients, 78 tested positive for Helicobacter pylori and 70 tested negative. Hematoxylin-eosin (HE) and immunofluorescence staining were utilized to quantify GDF6 expression in cancerous and adjacent tissues. Patient prognosis was monitored via follow-up. Western blotting analyzed GDF6 expression in common gastric cancer cell lines. HGC27 cells exhibiting high GDF6 expression and BGC823 cells with low expression were used to create GDF6-silenced and overexpressed cell lines. The impact of GDF6 on the proliferation, migration, invasion, and cloning abilities of gastric cancer cells was evaluated using the CCK-8 assay, scratch test, Transwell assay, and plate colony formation assay. Fluorescent quantitative PCR and Western blotting assessed the effects of GDF6 levels on epithelial-mesenchymal transition (EMT) and tumor cell stemness.

RESULTS

GDF6 expression in gastric cancer tissues was significantly correlated with cancer grading and staging (P<0.05). Helicobacter pylori-positive tissues exhibited significantly higher GDF6 expression levels than negative samples (P<0.05). Kaplan-Meier survival analysis indicated that high GDF6 expression was associated with poor survival prognosis. Overexpressed GDF6 enhanced the proliferation, migration, and invasion abilities of gastric cancer cells, while silencing GDF6 yielded opposite results. Increased GDF6 expression upregulated TGF-β expression and the phosphorylation levels of SMAD3, leading to an elevation in mesenchymal cell markers N-cadherin, vimentin, and a reduction in epithelial cell markers cytokeratins, E-cadherin. Moreover, high GDF6 levels contributed to increased resistance to capecitabine and enhanced the expression of tumor stem cell markers Nanog, Sox-2, Oct-4, CD44, amplifying tumor cell stemness.

CONCLUSION

Helicobacter pylori infection is associated with increased GDF6 expression in gastric cancer tissue, correlating with poor survival prognosis. Elevated GDF6 expression promotes the proliferation, migration, and invasion abilities of gastric cancer cells, facilitates EMT via the TGF-β/SMAD3 pathway, and intensifies cell stemness and capecitabine resistance. Consequently, GDF6 presents itself as a potential new target for gastric cancer treatment.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Genetically engineered nanomodulators elicit potent immunity against cancer stem cells by checkpoint blockade and hypoxia relief

Rapid development of checkpoint inhibitors has provided significant breakthroughs for cancer stem cell (CSC) therapy, while the therapeutic efficacy is restricted by hypoxia-mediated tumor immune evasion, especially hypoxia-induced CD47 overexpression in CSCs. Herein, we developed a genetically engineered CSC membrane-coated hollow manganese dioxide (hMnO2@gCMs) to elicit robust antitumor immunity by blocking CD47 and alleviating hypoxia to ultimately achieve the eradication of CSCs. The hMnO2 core effectively alleviated tumor hypoxia by inducing decomposition of tumor endogenous H2O2, thus suppressing the CSCs and reducing the expression of CD47. Cooperating with hypoxia relief-induced downregulation of CD47, the overexpressed SIRPα on gCM shell efficiently blocked the CD47-SIRPα "don't eat me" pathway, synergistically eliciting robust antitumor-mediated immune responses. In a B16F10-CSC bearing melanoma mouse model, the hMnO2@gCMs showed an enhanced therapeutic effect in eradicating CSCs and inhibiting tumor growth. Our work presents a simple, safe, and robust platform for CSC eradication and cancer immunotherapy.

Lactic acid: a narrative review of a promoter of the liver cancer microenvironment

Background and Objective

Lactic acid is a metabolite of glycolysis produced in the body, and its production is thought to be a mechanism by which cancer cells evade immune surveillance. Immune evasion and metabolic changes are well established as basic hallmarks of cancer. Although lactate has long been considered a waste product, it is now generally recognized to be a versatile small-molecule chemical that plays an important part in the tumor microenvironment (TME), with increased lactate production linked to the development of human malignancies. Metabolism in liver cancer is redirected toward glycolysis, which enhances the production of metabolic compounds used by tumor cells to produce proteins, lipids, and nucleotides, enabling them to maintain high proliferation rates and to establish the TME. Dysregulation of metabolic activity in liver cancer may impair antitumor responses owing to the immunosuppressive activity of the lactate produced by anaerobic glycolytic rates in tumor cells. This review primarily explores the link connection between lactic acid and the TME; evaluates the role of lactic acid in the occurrence, metastasis, prognosis, and treatment of liver cancer. Additionally, it investigates the associated pathways as potential targets for liver cancer treatment.

Methods

Literature searches were conducted in PubMed, Web of Science, and Google Scholar, with the publication date of the most recent article included being January 2024. After eliminating duplicate articles and less relevant articles through titles and abstracts, we selected 113 articles for this review. We categorized references into two categories. One is to classify the content into lactate-related, liver cancer-related and tumor metabolism-related. The other is to classify the article types, which are divided into reviews, research articles and clinical trials. Additionally, we consulted the reference lists of the relevant articles to ensure coverage was comprehensive and unbiased.

Key Content and Findings

The connection between lactic acid and the TME has recently become an area of intense research interest, and many related articles have been published in this field. The main finding of this review is to summarize the proven link between lactate and the TME and its possible impact on the TME of liver cancer. And analyzed the potential of lactate in liver cancer treatment and prognosis prediction.

Conclusions

Lactate may be key to developing novel approaches in the future treatment of liver cancer. Related research on the combination of classic therapies and molecular targeted drugs may provide innovative medicines that more selectively regulate immune cell activity.

Obg-like ATPase 1 exacerbated gemcitabine drug resistance of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant disease with a poor prognosis due to inefficient diagnosis and tenacious drug resistance. Obg-like ATPase 1 (OLA1) is overexpressed in many malignant tumors. The molecular mechanism of OLA1 underlying gemcitabine (GEM)-induced drug resistance was investigated in this study. An enhanced expression of OLA1 was observed in a GEM acquired resistant pancreatic cancer cell lines and in patients with pancreatic cancer. Overexpressed OLA1 showed poor overall survival rates in patients with pancreatic cancer. Dysregulation of the OLA1 reduced expression of CD44+/CD133+, and improved the sensitivity of pancreatic cancer cells to GEM. OLA1 highly expression facilitated the formation of the OLA1/Sonic Hedgehog (SHH)/Hedgehog-interacting protein (HHIP) complex in nuclei, resulting in the inhibition of negative feedback of Hedgehog signaling induced by HHIP. This study suggests that OLA1 may be developed as an innovative drug target for an effective therapy of pancreatic cancer.

Modulatory effects of cancer stem cell-derived extracellular vesicles on the tumor immune microenvironment

Cancer stem cells (CSCs), accounting for only a minor cell proportion (< 1%) within tumors, have profound implications in tumor initiation, metastasis, recurrence, and treatment resistance due to their inherent ability of self-renewal, multi-lineage differentiation, and tumor-initiating potential. In recent years, accumulating studies indicate that CSCs and tumor immune microenvironment act reciprocally in driving tumor progression and diminishing the efficacy of cancer therapies. Extracellular vesicles (EVs), pivotal mediators of intercellular communications, build indispensable biological connections between CSCs and immune cells. By transferring bioactive molecules, including proteins, nucleic acids, and lipids, EVs can exert mutual influence on both CSCs and immune cells. This interaction plays a significant role in reshaping the tumor immune microenvironment, creating conditions favorable for the sustenance and propagation of CSCs. Deciphering the intricate interplay between CSCs and immune cells would provide valuable insights into the mechanisms of CSCs being more susceptible to immune escape. This review will highlight the EV-mediated communications between CSCs and each immune cell lineage in the tumor microenvironment and explore potential therapeutic opportunities.

Mitophagy and cancer: role of BNIP3/BNIP3L as energetic drivers of stemness features, ATP production, proliferation, and cell migration

Mitophagy is a selective form of autophagy which permits the removal of dysfunctional or excess mitochondria. This occurs as an adaptative response to physiological stressors, such as hypoxia, nutrient deprivation, or DNA damage. Mitophagy is promoted by specific mitochondrial outer membrane receptors, among which are BNIP3 and BNIP3L. The role of mitophagy in cancer is being widely studied, and more specifically in the maintenance of cancer stem cell (CSC) properties, such as self-renewal. Given that CSCs are responsible for treatment failure and metastatic capacity, targeting mitophagy could be an interesting approach for CSC elimination. Herein, we describe a new model system to enrich sub-populations of cancer cells with high basal levels of mitophagy, based on the functional transcriptional activity of BNIP3 and BNIP3L. Briefly, we employed a BNIP3(L)-promoter-eGFP-reporter system to isolate cancer cells with high BNIP3/BNIP3L transcriptional activity by flow cytometry (FACS). The model was validated by using complementary lysosomal and mitophagy-specific probes, as well as the mitochondrially-targeted red fluorescent protein (RFP), namely mt-Keima. High BNIP3/BNIP3L transcriptional activity was accompanied by increases in i) BNIP3/BNIP3L protein levels, ii) lysosomal mass, and iii) basal mitophagy activity. Furthermore, cancer cells with increased BNIP3/BNIP3L transcriptional activity exhibited CSC features, such as greater mammosphere-forming ability and high CD44 levels. To further explore the model, we also analysed other stemness characteristics in MCF7 and MDA-MB-231 breast cancer cell lines, directly demonstrating that BNIP3(L)-high cells were more metabolically active, proliferative, migratory, and drug-resistant, with elevated anti-oxidant capacity. Therefore, high levels of basal mitophagy appear to enhance CSC features.

Clonal tracking in cancer and metastasis

The eradication of many cancers has proven challenging due to the presence of functionally and genetically heterogeneous clones maintained by rare cancer stem cells (CSCs), which contribute to disease progression, treatment refractoriness, and late relapse. The characterization of functional CSC activity has necessitated the development of modern clonal tracking strategies. This review describes viral-based and CRISPR-Cas9-based cellular barcoding, lineage tracing, and imaging-based approaches. DNA-based cellular barcoding technology is emerging as a powerful and robust strategy that has been widely applied to in vitro and in vivo model systems, including patient-derived xenograft models. This review also highlights the potential of these methods for use in the clinical and drug discovery contexts and discusses the important insights gained from such approaches.

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.

Unraveling metabolic characteristics and clinical implications in gastric cancer through single-cell resolution analysis

Background: Gastric cancer is a highly prevalent malignant neoplasm. Metabolic reprogramming is intricately linked to both tumorigenesis and cancer immune evasion. The advent of single-cell RNA sequencing technology provides a novel perspective for evaluating cellular metabolism. This study aims to comprehensively investigate the metabolic pathways of various cell types in tumor and normal samples at high resolution and delve into the intricate regulatory mechanisms governing the metabolic activity of malignant cells in gastric cancer. Methods: Utilizing single-cell RNA sequencing data from gastric cancer, we constructed metabolic landscape maps for different cell types in tumor and normal samples. Employing unsupervised clustering, we categorized malignant cells in tumor samples into high and low metabolic subclusters and further explored the characteristics of these subclusters. Results: Our research findings indicate that epithelial cells in tumor samples exhibit significantly higher activity in most KEGG metabolic pathways compared to other cell types. Unsupervised clustering, based on the scores of metabolic pathways, classified malignant cells into high and low metabolic subclusters. In the high metabolic subcluster, it demonstrated the potential to induce a stronger immune response, correlating with a relatively favorable prognosis. In the low metabolic subcluster, a subset of cells resembling cancer stem cells (CSCs) was identified, and its prognosis was less favorable. Furthermore, a set of risk genes associated with this subcluster was discovered. Conclusion: This study reveals the intricate regulatory mechanisms governing the metabolic activity of malignant cells in gastric cancer, offering new perspectives for improving prognosis and treatment strategies.

The intricate interplay between cancer stem cells and cell-of-origin of cancer: implications for therapeutic strategies

Background

Cancer stem cells (CSCs) have emerged as pivotal players in tumorigenesis, disease progression, and resistance to therapies.

Objective

This comprehensive review delves into the intricate relationship between CSCs and the cell-of-origin in diverse cancer types.

Design

Comprehensive review of thematically-relevant literature.

Methods

We explore the underlying molecular mechanisms that drive the conversion of normal cells into CSCs and the impact of the cell-of-origin on CSC properties, tumor initiation, and therapeutic responses. Moreover, we discuss potential therapeutic interventions targeting CSCs based on their distinct cell-of-origin characteristics.

Results

Accruing evidence suggest that the cell-of-origin, the cell type from which the tumor originates, plays a crucial role in determining the properties of CSCs and their contribution to tumor heterogeneity.

Conclusion

By providing critical insights into the complex interplay between CSCs and their cellular origins, this article aims to enhance our understanding of cancer biology and pave the way for more effective and personalized cancer treatments.

Ferroptosis: emerging roles in lung cancer and potential implications in biological compounds

Lung cancer has high metastasis and drug resistance. The prognosis of lung cancer patients is poor and the patients' survival chances are easily neglected. Ferroptosis is a programmed cell death proposed in 2012, which differs from apoptosis, necrosis and autophagy. Ferroptosis is a novel type of regulated cell death which is driven by iron-dependent lipid peroxidation and subsequent plasma membrane ruptures. It has broad prospects in the field of tumor disease treatment. At present, multiple studies have shown that biological compounds can induce ferroptosis in lung cancer cells, which exhibits significant anti-cancer effects, and they have the advantages in high safety, minimal side effects, and less possibility to drug resistance. In this review, we summarize the biological compounds used for the treatment of lung cancer by focusing on ferroptosis and its mechanism. In addition, we systematically review the current research status of combining nanotechnology with biological compounds for tumor treatment, shed new light for targeting ferroptosis pathways and applying biological compounds-based therapies.