Recent update on IGF-1/IGF-1R signaling axis as a promising therapeutic target for triple-negative breast cancer.

Insulin-like growth factor 1/Insulin-like growth factor 1-receptor (IGF-1/IGF-1R) pathway is highly breast cancer subtype context-dependent. Triple-negative breast cancer (TNBC) is an aggressive, highly metastatic cancer showing early recurrence and poor prognosis. High expression of IGF-1 and its receptor IGF-1R, their interaction, autophosphorylation, and activation of intracellular signaling cascades have been significantly associated with TNBC pathophysiology. In the last five to seven years, marvelous work has been done to explore the role of IGF-1/IGF-1R axis in TNBC. In the present review, starting from the general introduction to IGF-1/IGF-1R pathway an up-to-date discussion was focused on its role in TNBC pathophysiology. Further we discussed the up/down stream molecular events of IGF-1/IGF-1R axis, clinical relevance of IGF-1 and IGF-1R levels in TNBC patients, anti-TNBC therapy and possible way-out for IGF-1/IGF-1R axis mediate therapy resistance in TNBC. Combination therapy strategy has been researched to overcome direct IGF-1/IGF-1R pathway inhibition mediated therapy resistance and produced promising results in the management of TNBC. The understanding of up/downstream of the IGF-1/IGF-1R axis provide immense focus on the pathway as a therapeutic target. It is expected within the next decade to determine its potentiality, or lack thereof, for TNBC treatment.

The activation of asparagine synthetase by the transcription factor FOXM1 plays a pivotal role in the initiation and progression of ESCC.

This study explores the role of the transcription factor FOXM1 in the initiation and progression of oesophageal squamous cell carcinoma (ESCC). Our findings reveal that FOXM1 is highly expressed in ESCC and correlates with the prognosis of the disease. The relationship between FOXM1 and asparagine synthetase (ASNS) is investigated, and the study demonstrates that FOXM1 activates ASNS, impacting the tumour stemness of ESCC. In this study, we reveal the association between FOXM1 and ESCC development, as well as FOXM1's promotion of migration and proliferation in ESCC cells. The study also highlights FOXM1's regulation of ASNS transcription and the functional role of ASNS in ESCC metastasis and growth. Furthermore, the study explores the impact of FOXM1 and ASNS on ESCC stemness and their potential implications for chemotherapy resistance.

Understanding the autophagic functions in cancer stem cell maintenance and therapy resistance.

Complex tumour ecosystem comprising tumour cells and its associated tumour microenvironment (TME) constantly influence the tumoural behaviour and ultimately impact therapy failure, disease progression, recurrence and poor overall survival of patients. Crosstalk between tumour cells and TME amplifies the complexity by creating metabolic changes such as hypoxic environment and nutrient fluctuations. These changes in TME initiate stem cell-like programmes in cancer cells, contribute to tumoural heterogeneity and increase tumour robustness. Recent studies demonstrate the multifaceted role of autophagy in promoting fibroblast production, stemness, cancer cell survival during longer periods of dormancy, eventual growth of metastatic disease and disease resistance. Recent ongoing studies examine autophagy/mitophagy as a powerful survival strategy in response to environmental stress including nutrient deprivation, hypoxia and environmental stress in TME. It prevents irreversible senescence, promotes dormant stem-like state, induces epithelial-mesenchymal transition and increases migratory and invasive potential of tumour cells. The present review discusses various theories and mechanisms behind the autophagy-dependent induction of cancer stem cell (CSC) phenotype. Given the role of autophagic functions in CSC aggressiveness and therapeutic resistance, various mechanisms and studies based on suppressing cellular plasticity by blocking autophagy as a powerful therapeutic strategy to kill tumour cells are discussed.

Intricate relationship between cancer stemness, metastasis, and drug resistance.

Cancer stem cells (CSCs) are widely acknowledged as the drivers of tumor initiation, epithelial-mesenchymal transition (EMT) progression, and metastasis. Originating from both hematologic and solid malignancies, CSCs exhibit quiescence, pluripotency, and self-renewal akin to normal stem cells, thus orchestrating tumor heterogeneity and growth. Through a dynamic interplay with the tumor microenvironment (TME) and intricate signaling cascades, CSCs undergo transitions from differentiated cancer cells, culminating in therapy resistance and disease recurrence. This review undertakes an in-depth analysis of the multifaceted mechanisms underlying cancer stemness and CSC-mediated resistance to therapy. Intrinsic factors encompassing the TME, hypoxic conditions, and oxidative stress, alongside extrinsic processes such as drug efflux mechanisms, collectively contribute to therapeutic resistance. An exploration into key signaling pathways, including JAK/STAT, WNT, NOTCH, and HEDGEHOG, sheds light on their pivotal roles in sustaining CSCs phenotypes. Insights gleaned from preclinical and clinical studies hold promise in refining drug discovery efforts and optimizing therapeutic interventions, especially chimeric antigen receptor (CAR)-T cell therapy, cytokine-induced killer (CIK) cell therapy, natural killer (NK) cell-mediated CSC-targeting and others. Ultimately use of cell sorting and single cell sequencing approaches for elucidating the fundamental characteristics and resistance mechanisms inherent in CSCs will enhance our comprehension of CSC and intratumor heterogeneity, which ultimately would inform about tailored and personalized interventions.

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.

Black Tea Suppresses Invasiveness and Reverses TNF-α-Induced Invasiveness and Cell Stemness in Human Malignant Melanoma Cells.

Invasiveness and epithelial-mesenchymal transition (EMT) are main patterns of metastatic disease, which is the major cause cancer-related mortality in human malignant melanoma cells. Tea and its consumption extract are associated with a lower risk of several types of cancer and have anti-inflammatory and antioxidative biological effects. However, the anti-EMT and anti-cancer stemness effect of black tea ethanol extracts (BTEE) in human melanoma remain poorly understood. In this study, the effects of BTEE-reduced invasiveness, EMT, and cancer stemness were evaluated in human A 375 and A2058 melanoma cells. BTEE inhibited the activity of u-PA, migration, and invasiveness by repressing p-FAK signaling pathway. BTEE affected the EMT by downregulating the expression of ß-catenin, N-cadherin, fibronectin, vimentin, and Twist-1. BTEE also reduced tumor necrosis factor-alpha (TNF-α)-induced invasiveness and cancer stemness characteristics in vitro. The growth of melanoma in nude mice xenograft model showed that BTEE suppressed A 375 tumor growth in vivo.

Leucine drives LAT1-related SNAIL upregulation in glucose-starved pancreatic cancer cells.

Pancreatic cancer, a highly fibrotic and hypovascular tumor, is thought to have unique metabolic characteristics in surviving and proliferating in malnutritional microenvironments. In this study, we compared the differences in the ability of pancreatic cancer cells to adapt to glucose-free conditions with liver cancer cells, which are representative of hypervascular tumors. Three pancreatic cancer cells and two liver cancer cells were used to examine the transcriptional expression levels of molecules involved in intracellular amino acid uptake, epithelial-mesenchymal transition (EMT), and cancer stemness under glucose deprivation. The results showed that the proliferative activity of pancreatic cancer cells under glucose deprivation was significantly lower than that of liver cancer cells, but the expression levels of amino acid transporters were significantly higher. Among them, L-type amino acid transporter 1 (LAT1) upregulation was unique in concert with increased expression of the EMT regulator SNAIL and the cancer stemness marker doublecortin-like kinase 1. LAT1 knockdown canceled the upregulation of SNAIL in glucose-starved pancreatic cancer cells, suggesting a mechanistic link between the two molecules. When LAT1 was stimulated by its substrate leucine, the SNAIL expression was upregulated dose-dependently. Collectively, pancreatic cancer cells reprogrammed metabolism to adapt to energy crises involving leucine-induced SNAIL upregulation.

Injectable Hydrogel-Encapsulating Pickering Emulsion for Overcoming Lenvatinib-Resistant Hepatocellular Carcinoma via Cuproptosis Induction and Stemness Inhibition.

Lenvatinib resistance (LenR) presents a significant challenge in hepatocellular carcinoma (HCC) treatment, leading to high cancer-related mortality rates globally. Unlike traditional chemotherapy resistance mechanisms, LenR in HCC is primarily driven by increased cancer cell stemness. Disulfiram, (DSF), functioning as a Cu ionophore, can coordinate with Cu2+ to overcome LenR in HCC by inhibiting cancer cell stemness and cuproptosis. However, DSF faces challenges due to its poor water solubility, while copper ions present issues related to systemic toxicity during widespread use. To address this, DSF and CuO nanoparticles (NPs) were co-encapsulated to form an oil-in-water Pickering emulsion (DSF@CuO), effectively elevating DSF and copper ion concentrations within the tumor microenvironment (TME). DSF@CuO was then combined with sodium alginate (SA) to form a DSF@CuO-SA solution, which gelatinizes in situ with Ca2+ in the TME to form a DSF@CuO Gel, enhancing Pickering emulsion stability and sustaining DSF and copper ion release. A DSF@CuO Gel exhibits enhanced stability and therapeutic efficacy compared to conventional administration methods. It effectively induces mitochondrial dysfunction and cuproptosis in LenR HCC cells by downregulating DLAT, LIAS, and CDKN2A, while upregulating FDX1. Furthermore, it suppresses cancer stemness pathways through activation of the JNK/p38 MAPK pathway and inhibition of the NF-κB and NOTCH signaling pathways. These findings suggest that DSF@CuO Gels are a promising therapeutic strategy for treating LenR HCC. In vivo and in vitro LenR HCC models demonstrated significant therapeutic efficacy. In conclusion, this novel approach underscores DSF@CuO Gel's potential to overcome LenR in HCC, offering a novel approach to address this clinical challenge.

L1CAM mediates neuroendocrine phenotype acquisition in prostate cancer cells.

BACKGROUND: A specific type of prostate cancer (PC) that exhibits neuroendocrine (NE) differentiation is known as NEPC. NEPC has little to no response to androgen deprivation therapy and is associated with the development of metastatic castration-resistant PC (CRPC), which has an extremely poor prognosis. Our understanding of genetic drivers and activated pathways in NEPC is limited, which hinders precision medicine approaches. L1 cell adhesion molecule (L1CAM) is known to play an oncogenic role in metastatic cancers, including CRPC. However, the impact of L1CAM on NEPC progression remains elusive. METHODS: L1CAM expression level was investigated using public gene expression databases of PC cohorts and patient-derived xenograft models. L1CAM knockdown was performed in different PC cells to study in vitro cell functions. A subline of CRPC cell line CWR22Rv1 was established after long-term exposure to abiraterone to induce NE differentiation. The androgen receptor-negative cell line PC3 was cultured under the tumor sphere-forming condition to enrich cancer stemness features. Several oxidative stress inducers were tested on PC cells to observe L1CAM-mediated gene expression and cell death. RESULTS: L1CAM expression was remarkably high in NEPC compared to CRPC or adenocarcinoma tumors. L1CAM was also correlated with NE marker expressions and associated with the adenocarcinoma-to-NEPC progression in gene expression databases and CRPC cells with NE differentiation. L1CAM also promoted cancer stemness and NE phenotypes in PC3 cells under cancer stemness enrichment. L1CAM was also identified as a reactive oxygen species-induced gene, by which L1CAM counteracted CRPC cell death triggered by ionizing radiation. CONCLUSIONS: Our results unveiled a new role of L1CAM in the acquisition of the NE phenotype in PC, contributing to the NE differentiation-related therapeutic resistance of CRPC.

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-art predictive computational methods have facilitated the prediction of cancer stemness, currently there is no efficient resource that can meet various usage requirements. Here, we present the Cancer Stemness Online, an integrated resource for efficiently scoring cancer stemness potential at the bulk and single-cell levels. The resource integrates 8 robust predictive algorithms as well as 27 signature gene sets associated with cancer stemness for predicting stemness scores. Downstream analyses were performed from five different aspects, including identifying the signature genes of cancer stemness, exploring the associations with cancer hallmarks, cellular states, the immune response, and communication 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 the downstream functional interpretation, including immune response as well as cancer hallmarks. Cancer Stemness Online is freely accessible at http://bio-bigdata.hrbmu.edu.cn/CancerStemnessOnline.

Gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) promotes oral cancer stemness by acting as a molecular sponge of miR331-3p.

Background/purpose: Accumulating evidence has suggested that treatment failure of cancer therapy can be attributed to cancer stem cells (CSCs). Among numerous regulators of cancer stemness, non-coding RNAs (ncRNAs) have gained significant attention recently. In this study, we examined the role of gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) in oral CSCs (OCSCs). Materials and methods: RNA Sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the expression of GAPLINC. Flow cytometry and sphere-forming assay were exploited to isolate OCSCs. Measurement of aldehyde dehydrogenase 1 (ALDH1) activity, CD44 expressing cells, and various phenotypic assays, such as self-renewal, migration, invasion, and colony-forming abilities, were conducted in CSCs of two types of oral cancer cells (SAS and GNM) following the knockdown of GAPLINC. A luciferase reporter was also carried out to validate the direct interaction between GAPLINC and microRNA (miR)-331-3p. Results: Our results showed that GAPLINC was overexpressed in OCSCs from patient-derived and oral cancer cell lines. We demonstrated that silencing of GAPLINC in OCSCs downregulated various CSC hallmarks, such as ALDH1 activity, percentage of CD44-expressing cells, self-renewal capacity, and colony-forming ability. Moreover, our results revealed that the effect of GAPLINC on cancer stemness was mediated by direct repression of miR-331-3p. Conclusion: These data have potential clinical implications in that we unraveled the aberrant upregulation of GAPLINC and demonstrated that suppression of GAPLINC may reduce cancer stemness via sequestering miR-331-3p.

Metformin overcomes chemoresistance by regulating stemness via KLF4 in oral squamous cell carcinoma.

OBJECTIVE: Chemoresistance is a common event after chemotherapy, including oral squamous cell carcinoma (OSCC). Accumulated evidence suggests that the cancer stemness significantly contributes to therapy resistance. An unresolved question remains regarding how to effectively overcome OSCC chemoresistance by targeting stemness. This study aims to investigate the antitumor effect of metformin and clarify the potential molecular mechanisms. METHODS: Cellular models resistant to chemotherapy were established, and their viability and sphere-forming ability were assessed using CCK-8 and soft agar formation assays, respectively. RNA-seq and Western blotting analyses were employed to delve into the molecular pathways. Furthermore, to corroborate the inhibitory effects of metformin and cisplatin at an animal level, a subcutaneous tumor transplantation model was instituted. RESULTS: Metformin as a monotherapy exhibited inhibition of stemness traits via Krüppel-like factor 4 (KLF4). Metformin and cisplatin can synergically inhibit cell proliferation and induce cell apoptosis. Animal experiments confirmed the inhibitory effect of cisplatin and metformin on tumor in mice. CONCLUSION: Our study proposes a potential therapeutic approach of combining chemotherapy with metformin to overcome chemoresistance in OSCC.

Olanzapine suppresses mPFC activity-norepinephrine releasing to alleviate CLOCK-enhanced cancer stemness under chronic stress.

BACKGROUND: Olanzapine (OLZ) reverses chronic stress-induced anxiety. Chronic stress promotes cancer development via abnormal neuro-endocrine activation. However, how intervention of brain-body interaction reverses chronic stress-induced tumorigenesis remains elusive. METHODS: KrasLSL-G12D/WT lung cancer model and LLC1 syngeneic tumor model were used to study the effect of OLZ on cancer stemness and anxiety-like behaviors. Cancer stemness was evaluated by qPCR, western-blotting, immunohistology staining and flow-cytometry analysis of stemness markers, and cancer stem-like function was assessed by serial dilution tumorigenesis in mice and extreme limiting dilution analysis in primary tumor cells. Anxiety-like behaviors in mice were detected by elevated plus maze and open field test. Depression-like behaviors in mice were detected by tail suspension test. Anxiety and depression states in human were assessed by Hospital Anxiety and Depression Scale (HADS). Chemo-sensitivity of lung cancer was assessed by in vivo syngeneic tumor model and in vitro CCK-8 assay in lung cancer cell lines. RESULTS: In this study, we found that OLZ reversed chronic stress-enhanced lung tumorigenesis in both KrasLSL-G12D/WT lung cancer model and LLC1 syngeneic tumor model. OLZ relieved anxiety and depression-like behaviors by suppressing neuro-activity in the mPFC and reducing norepinephrine (NE) releasing under chronic stress. NE activated ADRB2-cAMP-PKA-CREB pathway to promote CLOCK transcription, leading to cancer stem-like traits. As such, CLOCK-deficiency or OLZ reverses NE/chronic stress-induced gemcitabine (GEM) resistance in lung cancer. Of note, tumoral CLOCK expression is positively associated with stress status, serum NE level and poor prognosis in lung cancer patients. CONCLUSION: We identify a new mechanism by which OLZ ameliorates chronic stress-enhanced tumorigenesis and chemoresistance. OLZ suppresses mPFC-NE-CLOCK axis to reverse chronic stress-induced anxiety-like behaviors and lung cancer stemness. Decreased NE-releasing prevents activation of ADRB2-cAMP-PKA-CREB pathway to inhibit CLOCK transcription, thus reversing lung cancer stem-like traits and chemoresistance under chronic stress.

Fibroblasts Promote Resistance to KRAS Silencing in Colorectal Cancer Cells.

Colorectal cancer (CRC) responses to KRAS-targeted inhibition have been limited due to low response rates, the mechanisms of which remain unknown. Herein, we explored the cancer-associated fibroblasts (CAFs) secretome as a mediator of resistance to KRAS silencing. CRC cell lines HCT15, HCT116, and SW480 were cultured either in recommended media or in conditioned media from a normal colon fibroblast cell line (CCD-18Co) activated with rhTGF-ß1 to induce a CAF-like phenotype. The expression of membrane stem cell markers was analyzed by flow cytometry. Stem cell potential was evaluated by a sphere formation assay. RNAseq was performed in KRAS-silenced HCT116 colonospheres treated with either control media or conditioned media from CAFs. Our results demonstrated that KRAS-silencing up-regulated CD24 and down-regulated CD49f and CD104 in the three cell lines, leading to a reduction in sphere-forming efficiency. However, CAF-secreted factors restored stem cell marker expression and increased stemness. RNA sequencing showed that CAF-secreted factors up-regulated genes associated with pro-tumorigenic pathways in KRAS-silenced cells, including KRAS, TGFß, NOTCH, WNT, MYC, cell cycle progression and exit from quiescence, epithelial-mesenchymal transition, and immune regulation. Overall, our results suggest that resistance to KRAS-targeted inhibition might derive not only from cell-intrinsic causes but also from external elements, such as fibroblast-secreted factors.

COLEC10 inhibits the stemness of hepatocellular carcinoma by suppressing the activity of ß-catenin signaling.

BACKGROUND: Liver cancer stem cells (CSCs) contribute to tumor initiation, progression, and recurrence in hepatocellular carcinoma (HCC). The Wnt/ß-catenin pathway plays a crucial role in liver cancer stemness, progression, metastasis, and drug resistance, but no clinically approved drugs have targeted this pathway efficiently so far. We aimed to elucidate the role of COLEC10 in HCC stemness. METHODS: The Cancer Genome Atlas (TCGA) and the Clinical Proteomic Tumor Analysis Consortium (CPTAC) databases were employed to search for the association between COLEC10 expression and HCC stemness. Colony formation, sphere formation, side population, and limiting dilution tumor initiation assays were used to identify the regulatory role of COLEC10 overexpression in the stemness of HCC cell lines. Wnt/ß-catenin reporter assay and immunoprecipitation were performed to explore the underlying mechanism. RESULTS: COLEC10 level was negatively correlated with HCC stemness. Elevated COLEC10 led to decreased expressions of EpCAM and AFP (alpha-fetoprotein), two common markers of liver CSCs. Overexpression of COLEC10 inhibited HCC cells from forming colonies and spheres, and reduced the side population numbers in vitro, as well as the tumorigenic capacity in vivo. Mechanically, we demonstrated that overexpression of COLEC10 suppressed the activity of Wnt/ß-catenin signaling by upregulating Wnt inhibitory factor WIF1 and reducing the level of cytoplasmic ß-catenin. COLEC10 overexpression promoted the interaction of ß-catenin with the component of destruction complex CK1α. In addition, KLHL22 (Kelch Like Family Member 22), a reported E3 ligase adaptor predicted to interact with CK1α, could facilitate COLEC10 monoubiquitination and degradation. CONCLUSION: COLEC10 inhibits HCC stemness by downregulating the Wnt/ß-catenin pathway, which is a promising target for liver CSC therapy.

The Epigenetic Modifiers HDAC2 and HDAC7 Inversely Associate with Cancer Stemness and Immunity in Solid Tumors.

Dysregulation of histone deacetylases (HDACs) is closely associated with cancer development and progression. Here, we comprehensively analyzed the association between all HDAC family members and several clinicopathological and molecular traits of solid tumors across 22 distinct tumor types, focusing primarily on cancer stemness and immunity. To this end, we used publicly available TCGA data and several bioinformatic tools (i.e., GEPIA2, TISIDB, GSCA, Enrichr, GSEA). Our analyses revealed that class I and class II HDAC proteins are associated with distinct cancer phenotypes. The transcriptomic profiling indicated that class I HDAC members, including HDAC2, are positively associated with cancer stemness, while class IIA HDAC proteins, represented by HDAC7, show a negative correlation to cancer stem cell-like phenotypes in solid tumors. In contrast to tumors with high amounts of HDAC7 proteins, the transcriptome signatures of HDAC2-overexpressing cancers are significantly enriched with biological terms previously determined as stemness-associated genes. Moreover, high HDAC2-expressing tumors are depleted with immune-related processes, and HDAC2 expression correlates with tumor immunosuppressive microenvironments. On the contrary, HDAC7 upregulation is significantly associated with enhanced immune responses, followed by enriched infiltration of CD4+ and CD8+ T cells. This is the first comprehensive report demonstrating robust and versatile associations between specific HDAC family members, cancer dedifferentiation, and anti-tumor immune statuses in solid tumors.

Transcriptional Up-Regulation of FBXW7 by KCa1.1 K+ Channel Inhibition through the Nrf2 Signaling Pathway in Human Prostate Cancer LNCaP Cell Spheroid Model.

The tumor suppressor gene F-box and WD repeat domain-containing (FBXW) 7 reduces cancer stemness properties by promoting the protein degradation of pluripotent stem cell markers. We recently demonstrated the transcriptional repression of FBXW7 by the three-dimensional (3D) spheroid formation of several cancer cells. In the present study, we found that the transcriptional activity of FBXW7 was promoted by the inhibition of the Ca2+-activated K+ channel, KCa1.1, in a 3D spheroid model of human prostate cancer LNCaP cells through the Akt-Nrf2 signaling pathway. The transcriptional activity of FBXW7 was reduced by the siRNA-mediated inhibition of the CCAAT-enhancer-binding protein C/EBP δ (CEBPD) after the transfection of miR223 mimics in the LNCaP spheroid model, suggesting the transcriptional regulation of FBXW7 through the Akt-Nrf2-CEBPD-miR223 transcriptional axis in the LNCaP spheroid model. Furthermore, the KCa1.1 inhibition-induced activation of FBXW7 reduced (1) KCa1.1 activity and protein levels in the plasma membrane and (2) the protein level of the cancer stem cell (CSC) markers, c-Myc, which is a molecule degraded by FBXW7, in the LNCaP spheroid model, indicating that KCa1.1 inhibition-induced FBXW7 activation suppressed CSC conversion in KCa1.1-positive cancer cells.

Astragali Radix-Curcumae Rhizoma herb pair reduces the stemness of colorectal cancer cells through HIF-2α/ß-catenin pathway.

BACKGROUND: Colorectal cancer (CRC) is one of the most common causes of cancer-related mortality and significantly impairs quality of life. Astragali Radix-Curcumae Rhizoma (AC) is widely employed in the treatment of CRC in Chinese medicine, but the precise mechanisms remain unclear. PURPOSE: This study aimed to elucidate the mechanisms by which AC inhibits CRC progression. METHODS: The active components of AC were identified using UPLC-MS/MS analysis. An orthotopic transplantation colorectal tumor model was established in BALB/c mice using the CT26-Lucifer cell line to evaluate the effects of AC. Tumor volumes were monitored using IVIS imaging technology. Histological examination of tumor morphology was performed with hematoxylin and eosin (H&E) staining. Transcriptomic sequencing of mouse tumor samples was conducted to identify critical pathways and molecular targets. The impact of AC on cell viability and migration was assessed using CCK-8 and wound healing assays, respectively. To investigate the effects of AC on CRC cells, an in vitro hypoxic model was established using cobalt chloride (CoCl2), a hypoxia inducer. HIF-2α overexpression was achieved by constructing stable lentiviral vectors. Key targets identified from RNA-seq, such as c-Myc, Ki-67, ß-catenin, cleaved caspase 3, CD133, and CD44, were evaluated using western blotting, qRT-PCR, and immunofluorescence assays. Epithelial-Mesenchymal Transition (EMT) and spheroid cloning assays were employed to evaluate phenotypic changes in cancer stem cells. RESULTS: Twelve components of AC were identified. AC effectively inhibited CRC progression in vivo. Transcriptomic analysis highlighted hypoxic signaling as a significantly enriched pathway, implicating its role in suppressing CRC progression by AC. In the hypoxic model, AC inhibited the proliferation and migration of CRC cells in vitro. Furthermore, AC reduced cancer stemness by downregulating stemness markers, inhibiting EMT, and decreasing tumor sphere formation. The downregulation of hypoxic responses and the shift in stemness by AC involved attenuation of HIF-2α and WNT/ß-catenin signaling. CONCLUSION: This study provides the first evidence that AC reduces the stemness of CRC and the inhibition of the transition of CRC to stem-like cells by AC is closely related to the downregulation of the HIF-2α/ß-catenin pathway, especially under hypoxic conditions.

Interplay among extracellular vesicles, cancer stemness and immune regulation in driving hepatocellular carcinoma progression.

The intricate interplay among extracellular vesicles, cancer stemness properties, and the immune system significantly impacts hepatocellular carcinoma (HCC) progression, treatment response, and patient prognosis. Extracellular vesicles (EVs), which are membrane-bound structures, play a pivotal role in conveying proteins, lipids, and nucleic acids between cells, thereby serving as essential mediators of intercellular communication. Since a lot of current research focuses on small extracellular vesicles (sEVs), with diameters ranging from 30 nm to 200 nm, this review emphasizes the role of sEVs in the context of interactions between HCC stemness-bearing cells and the immune cells. sEVs offer promising opportunities for the clinical application of innovative diagnostic and prognostic biomarkers in HCC. By specifically targeting sEVs, novel therapeutics aimed at cancer stemness can be developed. Ongoing investigations into the roles of sEVs in cancer stemness and immune regulation in HCC will broaden our understanding and ultimately pave the way for groundbreaking therapeutic interventions.

Improvement of current immunotherapies with engineered oncolytic viruses that target cancer stem cells.

The heterogeneity of the solid tumor microenvironment (TME) impairs the therapeutic efficacy of standard therapies and also reduces the infiltration of antitumor immune cells, all of which lead to tumor progression and invasion. In addition, self-renewing cancer stem cells (CSCs) support tumor dormancy, drug resistance, and recurrence, all of which might pose challenges to the eradication of malignant tumor masses with current therapies. Natural forms of oncolytic viruses (OVs) or engineered OVs are known for their potential to directly target and kill tumor cells or indirectly eradicate tumor cells by involving antitumor immune responses, including enhancement of infiltrating antitumor immune cells, induction of immunogenic cell death, and reprogramming of cold TME to an immune-sensitive hot state. More importantly, OVs can target stemness factors that promote tumor progression, which subsequently enhances the efficacy of immunotherapies targeting solid tumors, particularly the CSC subpopulation. Herein, we describe the role of CSCs in tumor heterogeneity and resistance and then highlight the potential and remaining challenges of immunotherapies targeting CSCs. We then review the potential of OVs to improve tumor immunogenicity and target CSCs and finally summarize the challenges within the therapeutic application of OVs in preclinical and clinical trials.