Epithelial-mesenchymal transition-related signaling pathways in gastric Cancer cells distinctively respond to long-term experimental ketosis.

BACKGROUND: The interrelationship between cellular metabolism and the epithelial-to-mesenchymal transition (EMT) process has made it an interesting topic to investigate the adjuvant effect of therapeutic diets in the treatment of cancers. However, the findings are controversial. In this study, the effects of glucose limitation along and with the addition of beta-hydroxybutyrate (bHB) were examined on the expression of specific genes and proteins of EMT, Wnt, Hedgehog, and Hippo signaling pathways, and also on cellular behavior of gastric cancer stem-like (MKN-45) and non-stem-like (KATO III) cells. METHODS AND RESULTS: The expression levels of chosen genes and proteins studied in cancer cells gradually adopted a low-glucose condition of one-fourth, along and with the addition of bHB, and compared to the unconditioned control cells. The long-term switching of the metabolic fuels successfully altered the expression profiles and behaviors of both gastric cancer cells. However, the results for some changes were the opposite. Glucose limitation along and with the addition of bHB reduced the CD44+ population in MKN-45 cells. In KATO III cells, glucose restriction increased the CD44+ population. Glucose deprivation alleviated EMT-related signaling pathways in MKN-45 cells but stimulated EMT in KATO III cells. Interestingly, bHB enrichment reduced the beneficial effect of glucose starvation in MKN-45 cells, but also alleviated the adverse effects of glucose restriction in KATO III cells. CONCLUSIONS: The findings of this research clearly showed that some controversial results in clinical trials for ketogenic diet in cancer patients stemmed from the different signaling responses of various cells to the metabolic changes in a heterogeneous cancer mass.

Targeting Telomere Dynamics as an Effective Approach for the Development of Cancer Therapeutics.

Telomere is a protective structure located at the end of chromosomes of eukaryotes, involved in maintaining the integrity and stability of the genome. Telomeres play an essential role in cancer progression; accordingly, targeting telomere dynamics emerges as an effective approach for the development of cancer therapeutics. Targeting telomere dynamics may work through multifaceted molecular mechanisms; those include the activation of anti-telomerase immune responses, shortening of telomere lengths, induction of telomere dysfunction and constitution of telomerase-responsive drug release systems. In this review, we summarize a wide variety of telomere dynamics-targeted agents in preclinical studies and clinical trials, and reveal their promising therapeutic potential in cancer therapy. As shown, telomere dynamics-active agents are effective as anti-cancer chemotherapeutics and immunotherapeutics. Notably, these agents may display efficacy against cancer stem cells, reducing cancer stem levels. Furthermore, these agents can be integrated with the capability of tumor-specific drug delivery by the constitution of related nanoparticles, antibody drug conjugates and HSA-based drugs.

Isolation and Characterization of a Novel Mammary Adenocarcinoma, MCa-P1362, with Hormone Receptor Expression, Human Epidermal Growth Factor Receptor 2 Positivity, and Enrichment in Cancer and Mesenchymal Stem Cells.

Preclinical models that display spontaneous metastasis are necessary to improve the therapeutic options for hormone receptor-positive breast cancers. Within this study, detailed cellular and molecular characterization was conducted on MCa-P1362, a newly established mouse model of metastatic breast cancer that is syngeneic in BALB/c mice. MCa-P1362 cancer cells express estrogen receptor, progesterone receptor, and the human epidermal growth factor receptor 2. MCa-P1362 cancer cells proliferate in vitro and in vivo in response to estrogen, yet do not depend on steroid hormones for growth and tumor progression. Analysis of MCa-P1362 tumor explants revealed the tumors contained a mixture of cancer cells and mesenchymal stromal cells. Through transcriptomic and functional analyses of both cancer and stromal cells, stem cells were detected within both populations. Functional studies demonstrated that MCa-P1362 cancer stem cells drove tumor initiation, whereas stromal cells from these tumors contributed to drug resistance. MCa-P1362 may serve as a useful preclinical model to investigate the cellular and molecular basis of breast tumor progression and therapeutic resistance.

CD44: a cancer stem cell marker and therapeutic target in leukemia treatment.

CD44 is a ubiquitous leukocyte adhesion molecule involved in cell-cell interaction, cell adhesion, migration, homing and differentiation. CD44 can mediate the interaction between leukemic stem cells and the surrounding extracellular matrix, thereby inducing a cascade of signaling pathways to regulate their various behaviors. In this review, we focus on the impact of CD44s/CD44v as biomarkers in leukemia development and discuss the current research and prospects for CD44-related interventions in clinical application.

Targeting NKG2D ligands in glioblastoma with a bispecific T-cell engager is augmented with conventional therapy and enhances oncolytic virotherapy of glioma stem-like cells.

BACKGROUND: Glioblastoma (GBM) almost invariably becomes resistant towards conventional treatment of radiotherapy and temozolomide (TMZ) chemotherapy, partly due to subpopulations of intrinsically resistant glioma stem-like cells (GSC). The oncolytic herpes simplex virus-1 G207 is a promising approach for GBM virotherapy although its efficacy in patients with GBM is often limited. Natural killer group 2 member D ligands (NKG2DLs) are minimally expressed by healthy cells but are upregulated by the DNA damage response (DDR) and in malignant cells with chronic DDR signaling, resulting in innate immune activation. METHODS: We have designed a bispecific T-cell engager (BiTE) capable of cross-linking CD3 on T cells with NKG2DL-expressing GBM cells. We then engineered the G207 virus to express the NKG2D BiTE and secrete it from infected cells. The efficacy of the free BiTE and BiTE delivered by G207 was evaluated in combination with conventional therapies in GBM cells and against patient-derived GSCs in the context of T-cell activation and target cell viability. RESULTS: NKG2D BiTE-mediated cross-linking of GBM cells and T cells causes antigen-independent T-cell activation, pro-inflammatory cytokine release, and tumor cell death, thereby combining direct viral oncolysis with BiTE-mediated cytotoxicity. Surface NKG2DL expression was further elevated on GBM cells following pretreatment with sublethal doses of TMZ and radiation to induce the DDR, increasing sensitivity towards G207-NKG2D BiTE and achieving synergistic cytotoxicity. We also demonstrate a novel strategy for targeting GSCs that are non-permissive to G207 infection but remain sensitive to NKG2D BiTE. CONCLUSIONS: We propose a potential model for targeting GSCs in heterogeneous tumors, whereby differentiated GBM cells infected with G207-NKG2D BiTE produce NKG2D BiTE locally, directing T-cell cytotoxicity towards the GSC subpopulations in the tumor microenvironment.

Pervasive structural heterogeneity rewires glioblastoma chromosomes to sustain patient-specific transcriptional programs.

Glioblastoma multiforme (GBM) encompasses brain malignancies marked by phenotypic and transcriptional heterogeneity thought to render these tumors aggressive, resistant to therapy, and inevitably recurrent. However, little is known about how the spatial organization of GBM genomes underlies this heterogeneity and its effects. Here, we compile a cohort of 28 patient-derived glioblastoma stem cell-like lines (GSCs) known to reflect the properties of their tumor-of-origin; six of these were primary-relapse tumor pairs from the same patient. We generate and analyze 5 kbp-resolution chromosome conformation capture (Hi-C) data from all GSCs to systematically map thousands of standalone and complex structural variants (SVs) and the multitude of neoloops arising as a result. By combining Hi-C, histone modification, and gene expression data with chromatin folding simulations, we explain how the pervasive, uneven, and idiosyncratic occurrence of neoloops sustains tumor-specific transcriptional programs via the formation of new enhancer-promoter contacts. We also show how even moderately recurrent neoloops can relate to patient-specific vulnerabilities. Together, our data provide a resource for dissecting GBM biology and heterogeneity, as well as for informing therapeutic approaches.

The Effect of Intratumor Heterogeneity in Pancreatic Ductal Adenocarcinoma Progression and Treatment.

BACKGROUND AND OBJECTIVES: Pancreatic cancer is one of the most lethal malignancies. Even though many substantial improvements in the survival rates for other major cancer forms were made, pancreatic cancer survival rates have remained relatively unchanged since the 1960s. Even more, no standard classification system for pancreatic cancer is based on cellular biomarkers. This review will discuss and provide updates about the role of stem cells in the progression of PC, the genetic changes associated with it, and the promising biomarkers for diagnosis. MATERIALS AND METHODS: The search process used PubMed, Cochrane Library, and Scopus databases to identify the relevant and related articles. Articles had to be published in English to be considered. RESULTS: The increasing number of studies in recent years has revealed that the diversity of cancer-associated fibroblasts is far greater than previously acknowledged, which highlights the need for further research to better understand the various cancer-associated fibroblast subpopulations. Despite the huge diversity in pancreatic cancer, some common features can be noted to be shared among patients. Mutations involving CDKN2, P53, and K-RAS can be seen in a big number of patients, for example. Similarly, some patterns of genes and biomarkers expression and the level of their expression can help in predicting cancer behavior such as metastasis and drug resistance. The current trend in cancer research, especially with the advancement in technology, is to sequence everything in hopes of finding disease-related mutations. CONCLUSION: Optimizing pancreatic cancer treatment requires clear classification, understanding CAF roles, and exploring stroma reshaping approaches.

AI identifies potent inducers of breast cancer stem cell differentiation based on adversarial learning from gene expression data.

Cancer stem cells (CSCs) are a subpopulation of cancer cells within tumors that exhibit stem-like properties and represent a potentially effective therapeutic target toward long-term remission by means of differentiation induction. By leveraging an artificial intelligence approach solely based on transcriptomics data, this study scored a large library of small molecules based on their predicted ability to induce differentiation in stem-like cells. In particular, a deep neural network model was trained using publicly available single-cell RNA-Seq data obtained from untreated human-induced pluripotent stem cells at various differentiation stages and subsequently utilized to screen drug-induced gene expression profiles from the Library of Integrated Network-based Cellular Signatures (LINCS) database. The challenge of adapting such different data domains was tackled by devising an adversarial learning approach that was able to effectively identify and remove domain-specific bias during the training phase. Experimental validation in MDA-MB-231 and MCF7 cells demonstrated the efficacy of five out of six tested molecules among those scored highest by the model. In particular, the efficacy of triptolide, OTS-167, quinacrine, granisetron and A-443654 offer a potential avenue for targeted therapies against breast CSCs.

NANOG controls testicular germ cell tumour stemness through regulation of MIR9-2.

BACKGROUND: Testicular germ cell tumours (TGCTs) represent a clinical challenge; they are most prevalent in young individuals and are triggered by molecular mechanisms that are not fully understood. The origin of TGCTs can be traced back to primordial germ cells that fail to mature during embryonic development. These cells express high levels of pluripotency factors, including the transcription factor NANOG which is highly expressed in TGCTs. Gain or amplification of the NANOG locus is common in advanced tumours, suggesting a key role for this master regulator of pluripotency in TGCT stemness and malignancy. METHODS: In this study, we analysed the expression of microRNAs (miRNAs) that are regulated by NANOG in TGCTs via integrated bioinformatic analyses of data from The Cancer Genome Atlas and NANOG chromatin immunoprecipitation in human embryonic stem cells. Through gain-of-function experiments, MIR9-2 was further investigated as a novel tumour suppressor regulated by NANOG. After transfection with MIR9-2 mimics, TGCT cells were analysed for cell proliferation, invasion, sensitivity to cisplatin, and gene expression signatures by RNA sequencing. RESULTS: For the first time, we identified 86 miRNAs regulated by NANOG in TGCTs. Among these, 37 miRNAs were differentially expressed in NANOG-high tumours, and they clustered TGCTs according to their subtypes. Binding of NANOG within 2 kb upstream of the MIR9-2 locus was associated with a negative regulation. Low expression of MIR9-2 was associated with tumour progression and MIR9-2-5p was found to play a role in the control of tumour stemness. A gain of function of MIR9-2-5p was associated with reduced proliferation, invasion, and sensitivity to cisplatin in both embryonal carcinoma and seminoma tumours. MIR9-2-5p expression in TGCT cells significantly reduced the expression of genes regulating pluripotency and cell division, consistent with its functional effect on reducing cancer stemness. CONCLUSIONS: This study provides new molecular insights into the role of NANOG as a key determinant of pluripotency in TGCTs through the regulation of MIR9-2-5p, a novel epigenetic modulator of cancer stemness. Our data also highlight the potential negative feedback mediated by MIR9-2-5p on NANOG expression, which could be exploited as a therapeutic strategy for the treatment of TGCTs.

CSChighE-cadherinlow immunohistochemistry panel predicts poor prognosis in oral squamous cell carcinoma.

Identifying marker combinations for robust prognostic validation in primary tumour compartments remains challenging. We aimed to assess the prognostic significance of CSC markers (ALDH1, CD44, p75NTR, BMI-1) and E-cadherin biomarkers in OSCC. We analysed 94 primary OSCC and 67 metastatic lymph node samples, including central and invasive tumour fronts (ITF), along with clinicopathological data. We observed an increase in ALDH1+/CD44+/BMI-1- tumour cells in metastatic lesions compared to primary tumours. Multivariate analysis highlighted that elevated p75NTR levels (at ITF) and reduced E-cadherin expression (at the tumour centre) independently predicted metastasis, whilst ALDH1high exhibited independent predictive lower survival at the ITF, surpassing the efficacy of traditional tumour staging. Then, specifically at the ITF, profiles characterized by CSChighE-cadherinlow (ALDH1highp75NTRhighE-cadherinlow) and CSCintermediateE-cadherinlow (ALDH1 or p75NTRhighE-cadherinlow) were significantly associated with worsened overall survival and increased likelihood of metastasis in OSCC patients. In summary, our study revealed diverse tumour cell profiles in OSCC tissues, with varying CSC and E-cadherin marker patterns across primary tumours and metastatic sites. Given the pivotal role of reduced survival rates as an indicator of unfavourable prognosis, the immunohistochemistry profile identified as CSChighE-cadherinlow at the ITF of primary tumours, emerges as a preferred prognostic marker closely linked to adverse outcomes in OSCC.

Circ-0075305 hinders gastric cancer stem cells by indirectly disrupting TCF4-ß-catenin complex and downregulation of SOX9.

CircRNAs are covalently closed, single-stranded RNA that form continuous loops and play a crucial role in the initiation and progression of tumors. Cancer stem cells (CSCs) are indispensable for cancer development; however, the regulation of cancer stem cell-like properties in gastric cancer (GC) and its specific mechanism remain poorly understood. We elucidate the specific role of Circ-0075305 in GC stem cell properties. Circ-0075305 associated with chemotherapy resistance was identified by sequencing GC cells. Subsequent confirmation in both GC tissues and cell lines revealed that patients with high expression of Circ-0075305 had significantly better overall survival (OS) rates than those with low expression, particularly when treated with postoperative adjuvant chemotherapy for GC. In vitro and in vivo experiments confirmed that overexpression of Circ-0075305 can effectively reduce stem cell-like properties and enhance the sensitivity of GC cells to Oxaliplatin compared with the control group. Circ-0075305 promotes RPRD1A expression by acting as a sponge for corresponding miRNAs. The addition of LF3 (a ß-catenin/TCF4 interaction antagonist) confirmed that RPRD1A inhibited the formation of the TCF4-ß-catenin transcription complex through competitive to ß-catenin and suppressed the transcriptional activity of stem cell markers such as SOX9 via the Wnt/ß-catenin signaling pathway. This leads to the downregulation of stem cell-like property-related markers in GC. This study revealed the underlying mechanisms that regulate Circ-0075305 in GCSCs and suggests that its role in reducing ß-catenin signaling may serve as a potential therapeutic candidate.

Glioblastoma stem cells deliver ABCB4 transcribed by ATF3 via exosomes conferring glioblastoma resistance to temozolomide.

Glioblastoma stem cells (GSCs) play a key role in glioblastoma (GBM) resistance to temozolomide (TMZ) chemotherapy. With the increase in research on the tumour microenvironment, exosomes secreted by GSCs have become a new focus in GBM research. However, the molecular mechanism by which GSCs affect drug resistance in GBM cells via exosomes remains unclear. Using bioinformatics analysis, we identified the specific expression of ABCB4 in GSCs. Subsequently, we established GSC cell lines and used ultracentrifugation to extract secreted exosomes. We conducted in vitro and in vivo investigations to validate the promoting effect of ABCB4 and ABCB4-containing exosomes on TMZ resistance. Finally, to identify the transcription factors regulating the transcription of ABCB4, we performed luciferase assays and chromatin immunoprecipitation-quantitative PCR. Our results indicated that ABCB4 is highly expressed in GSCs. Moreover, high expression of ABCB4 promoted the resistance of GSCs to TMZ. Our study found that GSCs can also transmit their highly expressed ABCB4 to differentiated glioma cells (DGCs) through exosomes, leading to high expression of ABCB4 in these cells and promoting their resistance to TMZ. Mechanistic studies have shown that the overexpression of ABCB4 in GSCs is mediated by the transcription factor ATF3. In conclusion, our results indicate that GSCs can confer resistance to TMZ in GBM by transmitting ABCB4, which is transcribed by ATF3, through exosomes. This mechanism may lead to drug resistance and recurrence of GBM. These findings contribute to a deeper understanding of the mechanisms underlying drug resistance in GBM and provide novel insights into its treatment.

Cholesterol neutralized vemurafenib treatment by promoting melanoma stem-like cells via its metabolite 27-hydroxycholesterol.

Vemurafenib has been used as first-line therapy for unresectable or metastatic melanoma with BRAFV600E mutation. However, overall survival is still limited due to treatment resistance after about one year. Therefore, identifying new therapeutic targets for melanoma is crucial for improving clinical outcomes. In the present study, we found that lowering intracellular cholesterol by knocking down DHCR24, the limiting synthetase, impaired tumor cell proliferation and migration and abrogated the ability to xenotransplant tumors. More importantly, administration of DHCR24 or cholesterol mediated resistance to vemurafenib and promoted the growth of melanoma spheroids. Mechanistically, we identified that 27-hydroxycholesterol (27HC), a primary metabolite of cholesterol synthesized by the enzyme cytochrome P450 27A1 (CYP27A1), reproduces the phenotypes induced by DHCR24 or cholesterol administration and activates Rap1-PI3K/AKT signaling. Accordingly, CYP27A1 is highly expressed in melanoma patients and upregulated by DHCR24 induction. Dafadine-A, a CYP27A1 inhibitor, attenuates cholesterol-induced growth of melanoma spheroids and abrogates the resistance property of vemurafenib-resistant melanoma cells. Finally, we confirmed that the effects of cholesterol on melanoma resistance require its metabolite 27HC through CYP27A1 catalysis, and that 27HC further upregulates Rap1A/Rap1B expression and increases AKT phosphorylation. Thus, our results suggest that targeting 27HC may be a useful strategy to overcome treatment resistance in metastatic melanoma.

Vasorin promotes endothelial differentiation of glioma stem cells via stimulating the transcription of VEGFR2.

Gliomas are highly vascularized malignancies, but current anti-angiogenic treatments have not demonstrated practical improvements in patient survival. Studies have suggested that glioma-derived endothelial cell (GdEC) formed by glioma stem cell (GSC) differentiation may contribute to the failure of this treatment. However, the molecular mechanisms involved in GSC endothelial differentiation remain poorly understood. We previously reported that vasorin (VASN) is highly expressed in glioma and promotes angiogenesis. Here, we show that VASN expression positively correlates with GdEC signatures in glioma patients. VASN promotes the endothelial differentiation capacity of GSC in vitro and participates in the formation of GSC-derived vessels in vivo. Mechanistically, vascular endothelial growth factor receptor 2 (VEGFR2) is a critical factor that mediates the regulation of VASN on GSC endothelial differentiation. Separation of cell chromatin fractionation and chromatin immunoprecipitation-sequencing analysis show that VASN interacts with Notch1 and co-translocates into the cell nuclei, where VASN binds to the VEGFR2 gene promoter to stimulate its transcription during the progression of GSC differentiation into GdEC. Together, these findings elucidate the role and mechanisms of VASN in promoting the endothelial differentiation of GSC and suggest VASN as a potential target for anti-angiogenic therapy based on intervention in GdEC formation in gliomas.

Hallmarks of cancer stemness.

Cancer stemness is recognized as a key component of tumor development. Previously coined "cancer stem cells" (CSCs) and believed to be a rare population with rigid hierarchical organization, there is good evidence to suggest that these cells exhibit a plastic cellular state influenced by dynamic CSC-niche interplay. This revelation underscores the need to reevaluate the hallmarks of cancer stemness. Herein, we summarize the techniques used to identify and characterize the state of these cells and discuss their defining and emerging hallmarks, along with their enabling and associated features. We also highlight potential future directions in this field of research.

Cancer stem-like cells in uveal melanoma: novel insights and therapeutic implications.

Uveal melanoma (UM) is the most common primary ocular tumor in the adult population. Even though these primary tumors are successfully treated in 90% of cases, almost 50% of patients ultimately develop metastasis, mainly in the liver, via hematological dissemination, with a median survival spanning from 6 to 12 months after diagnosis. In this context, chemotherapy regimens and molecular targeted therapies have demonstrated poor response rates and failed to improve survival. Among the multiple reasons for therapy failure, the presence of cancer stem-like cells (CSCs) represents the main cause of resistance to anticancer therapies. In the last few years, the existence of CSCs in UM has been demonstrated both in preclinical and clinical studies, and new molecular pathways and mechanisms have been described for this subpopulation of UM cells. Here, we will discuss the state of the art of CSC biology and their potential exploitation as therapeutic target in UM.

Impact of HMGB1 on cancer development and therapeutic insights focused on CNS malignancy.

The present study explores the complex roles of High Mobility Group Box 1 (HMGB1) in the context of cancer development, emphasizing glioblastoma (GBM) and other central nervous system (CNS) cancers. HMGB1, primarily known for its involvement in inflammation and angiogenesis, emerges as a multifaceted player in the tumorigenesis of GBM. The overexpression of HMGB1 correlates with glioma malignancy, influencing key pathways like RAGE/MEK/ERK and RAGE/Rac1. Additionally, HMGB1 secretion is linked to the maintenance of glioma stem cells (GSCs) and contributes to the tumor microenvironment's (TME) vascular leakiness. Henceforth, our review discusses the bidirectional impact of HMGB1, acting as both a promoter of tumor progression and a mediator of anti-tumor immune responses. Notably, HMGB1 exhibits tumor-suppressive roles by inducing apoptosis, limiting cellular proliferation, and enhancing the sensitivity of GBM to therapeutic interventions. This dualistic nature of HMGB1 calls for a nuanced understanding of its implications in GBM pathogenesis, offering potential avenues for more effective and personalized treatment strategies. The findings underscore the need to explore HMGB1 as a prognostic marker, therapeutic target, and a promising tool for stimulating anti-tumor immunity in GBM.

Oxidative stress is two-sided in the treatment of acute myeloid leukemia.

INTRODUCTION: Oxidative stress caused by elevated ROS, as a novel therapeutic mechanism, has been implicated in various tumors including AML. AML cells are chronically under oxidative stress, yet overreliance on ROS production makes tumor cells increasingly vulnerable to further damage. Reducing the cytotoxic effect of ROS on normal cells while killing leukemia stem cell (LSC) with high levels of reactive oxygen species is a new challenge for oxidative stress therapy in leukemia. METHODS: By searching literature databases, we summarized recent relevant studies. The relationship of ROS on AML genes, signaling pathways, and transcription factors, and the correlation of ROS with AML bone marrow microenvironment and autophagy were summarized. In addition, we summarize the current status of research on ROS and AML therapeutics. Finally, we discuss the research progress on redox resistance in AML. RESULTS: This review discusses the evidence showing the link between redox reactions and the progression of AML and compiles the latest research findings that will facilitate future biological studies of redox effects associated with AML treatment. CONCLUSION: We believe that exploiting this unique oxidative stress property of AML cells may provide a new way to prevent relapse and drug resistance.