Bioassay of human tumor stem cells. A new approach to evaluation and treatment of cancer.
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Biological Assay↗
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Results for “Cancer stem cells”
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Excess folate elevates formaldehyde genotoxicity in cell lines but not in mice or humans.
Folate metabolites are chemically unstable: spontaneous decomposition releases formaldehyde, a genotoxin in blood stem cells and a human carcinogen. Despite this, folic acid consumption frequently exceeds the Recommended Dietary Allowance and is prescribed at high doses for patients with blood disorders. However, the impact of excess folate on endogenous formaldehyde genotoxicity in vivo has not been studied. We find that excess tetrahydrofolate (THF) treatment of cell lines elevates formaldehyde-DNA adducts and genotoxicity. To test this in vivo, we fed a high-folic acid diet (10-fold above standard) to mice with heightened sensitivity to formaldehyde: detoxification-impaired Adh5-/- mice, and Fanconi anemia DNA repair mutants Fanca-/- and Fancj-/-. In contrast to cell lines, elevated tissue THF was not associated with increased formaldehyde-DNA adducts nor blood stem cell attrition. Finally, in cancer patients, high-dose folic acid therapy elevated plasma folic acid but did not increase formaldehyde-DNA adducts in peripheral blood mononuclear cells. In conclusion, increased folate in vivo does not elevate endogenous formaldehyde genotoxicity in sensitized mouse models or humans.
Animals↗
Cancer stemness-modulating (CSM) proteins in pan-cancer chemoresistance: regulatory roles and mechanisms.
Cancer stemness is a property of cancer cells that plays critical roles in tumorigenesis and therapeutic resistance. We previously identified and categorized, based on literature evidence, a group of fourteen cancer stemness-modulating (CSM) circular RNAs (circRNAs) in colorectal cancer (CRC), which we termed CSM-circRNAs. In the present work, we show that the proteins regulated by these CRC CSM-circRNAs, with one exception for which information is currently unavailable, are bona fide modulators of cancer stemness across a wide range of cancer types. We, therefore, designate these proteins as CSM-proteins. As chemoresistance is a major trait of cancer stemness, we further investigated the molecular mechanisms through which CSM-proteins contribute to chemoresistance. Our analysis reveals that twelve CRC CSM-proteins are implicated in chemoresistance across fourteen cancer types and resistance to ten therapeutic agents. Nine distinct chemoresistance mechanisms are identified and organized into five broader functional axes: survival, drug processing, genome maintenance, plasticity and adaptation, leading us to propose an integrated mechanistic framework for CSM-protein-mediated chemoresistance. Most CSM-proteins operate across multiple functional axes in different cancer contexts, with survival-associated mechanisms, particularly apoptosis evasion, and epithelial-mesenchymal transition-associated plasticity emerging as the predominant modes of chemoresistance. Furthermore, transcriptional regulatory CSM-proteins exhibit broader mechanistic profiles than other molecular categories, although the strength and extent of evidence vary across proteins and cancer types. Taken together, the proposed CSM-protein pan-cancer chemoresistance framework offers a biologically and therapeutically relevant regulatory network for understanding the mechanisms underlying cancer chemoresistance based predominantly on preclinical evidence. Our findings may provide a preclinical conceptual foundation for the development of combinatorial therapeutic strategies targeting cancer stemness and chemoresistance through the CSM-circRNA-CSM-protein regulatory axis.
Cancer stemness↗
Ischemic Injury Drives Nascent Tumor Growth Via Accelerated Hematopoietic Aging.
BACKGROUND: Patients with peripheral artery disease have an increased risk of cancer development. Aging-associated changes in hematopoietic stem and progenitor cells (HSPCs), including inflammation and increased myelopoiesis, are implicated in both cardiovascular disease and cancer, but their contributions to cardiovascular disease-driven tumor progression are unclear. OBJECTIVES: This study sought to study tumor growth after peripheral ischemia and consequent changes within the HSPC bone marrow compartment to uncover mechanisms through which altered hematopoiesis promotes cancer. METHODS: Mammary cancer (E0771) growth was monitored in C57BL/6J mice after hind limb ischemia (HLI) or sham surgery. The tumor immune microenvironment, circulatory immune cells, and HSPC compartment were assessed by flow cytometry. Next-generation single-cell RNA and assay for transposase-accessible chromatin sequencing of bone marrow progenitors was performed to assess the distinct and synergistic transcriptomic and epigenetic changes of cancer and peripheral ischemia. The functional impact on tumor progression and persistence of ischemia-induced epigenetic reprogramming of HSPCs and their myeloid progeny was examined by bone marrow transplantation. RESULTS: Peripheral ischemia increased monocyte and neutrophil output at the expense of lymphocytes, driven by a shift toward CD150hi myeloid-biased hematopoietic stem cells. This was associated with accelerated cancer growth and enrichment of tumors with myeloid cells (monocytes, macrophages, neutrophils) and regulatory T cells. Increased myelopoiesis was also supported by sequencing analyses showing HLI and tumor-induced transcriptional and epigenetic enrichment for inflammatory (NLRP3 inflammasome) and aging-associated neogenin-1, thrombospondin-1) signatures in subsets of monocyte/dendritic progenitors. HLI-accelerated tumor growth and myeloid-skewing was transmissible via bone marrow transplantation, indicating long-term reprogramming of innate immune responses. CONCLUSIONS: Peripheral ischemia enhances inflammaging of hematopoietic stem cells and long-lasting alterations to antitumoral immunity, accelerating breast tumor growth.
bone marrow transplantation↗
Extracellular Vesicles Profiling in Acute Myeloid Leukemia Cell Lines: A Proteomic Characterization.
Extracellular vesicles (EVs) express features of parental cells and are fundamental in modulating the crosstalk between cancer cells and their environment. Increasing evidence suggests that EVs have a pivotal role in tumorigenesis, cancer development, and drug resistance. EVs are also involved in controlling the communication between hematopoietic stem cells and the surrounding microenvironment in the bone marrow (BM), during several processes such as self-renewal, mobilization, and lineage differentiation. Proteins expressed in cancer cell-derived EVs can be useful to further understand the regulation of hematopoietic stem cell fate, a fundamental mechanism in acute myeloid leukemia (AML). Furthermore, EVs are implicated in transmitting drug-resistance mechanisms in solid and not-solid cancer types. Here, using a proteomic approach, we analyze and validate the protein profile of EVs from three AML cell lines with different genotypes, namely OCI-AML-2, OCI-AML-3, and HL-60. The majority of the identified proteins were significantly enriched in the Gene Ontology category 'Extracellular Exosome'. Network model analysis of EV proteins revealed several significantly modulated pathways, including inflammation activation and metastatic processes in AML cell-derived EVs. The EVs proteomic profiling allows us to identify the EVs-associated molecules and pathways that could impact cancer progression and drug resistance.
Humans↗
Primary bioassay of human tumor stem cells.
A simple method has been developed to support human tumor stem cell colony growth in soft agar. The technique appears suitable for culture of a variety of neoplasms of differing histopathology. Tumor stem cell colonies arising from different types of cancer have differing growth characteristics and colony morphology. This bioassay should be suitable for clinical studies of effects of anticancer drugs or irradiation on human tumor stem cells.
Adenocarcinoma↗
Measurable Residual Disease and the Unresolved Biology of Leukemic Stem Cells.
Measurable residual disease (MRD) testing has transformed the management of hematologic cancers by enabling detection of residual malignant cells after therapy. Current approaches rely on qPCR and next-generation sequencing to monitor leukemia-associated somatic mutations, while multiparameter flow cytometry identifies aberrant leukemic immunophenotypes. Although these methods provide valuable prognostic and therapeutic information, MRD negativity remains an imperfect surrogate for cure. Most MRD platforms evaluate CD45+, rapidly dividing leukemic populations and fail to detect quiescent cells that may survive cytotoxic therapies which efficiently target proliferating hematopoietic cells. Relapse frequently occurs despite deep molecular remission, suggesting persistence of rare leukemic stem cells (LSCs) that are intrinsically resistant to chemotherapy and targeted therapies. The paradox of relapse despite molecular remission could be explained by the presence of very small embryonic-like stem cells (VSELs) which are pluripotent, quiescent stem cells sitting at the top of cellular hierarchy in multiple adult tissues including bone marrow. A pluripotent VSEL divides through asymmetrical cell division to give rise to two cells of different sizes and fates, smaller cell is to self-renew while the bigger is lineage-restricted and tissue-committed progenitor which undergoes extensive epigenetic changes, divides rapidly and undergoes clonal expansion before further differentiation. Dysfunctions of VSELs initiate both solid and hematologic cancers. Based on this view, somatic mutations monitored during MRD assessment possibly represent downstream consequences of clonal expansion rather than the initiating drivers of disease persistence. Thus, exclusive monitoring of somatic mutations and CD45 + leukemic populations possibly overlook rare, small-sized, CD45- VSELs that contribute to therapeutic resistance and relapse.
Humans↗
Ectopic expression of DNMT3L in human trophoblast stem cells restores features of the placental methylome.
The placental DNA methylation landscape is unique, with widespread partially methylated domains (PMDs). The placental "methylome" is conserved across mammals, a shared feature of many cancers, and extensively studied for links with pregnancy complications. Human trophoblast stem cells (hTSCs) offer exciting potential for functional studies to better understand this epigenetic feature; however, whether the hTSC epigenome recapitulates primary trophoblast remains unclear. We find that hTSCs exhibit an atypical methylome compared with trophectoderm and 1st trimester cytotrophoblast. Regardless of cell origin, oxygen levels, or culture conditions, hTSCs show localized DNA methylation within transcribed gene bodies and a complete loss of PMDs. Unlike early human trophoblasts, hTSCs display a notable absence of DNMT3L expression, which is necessary for PMD establishment in mouse trophoblasts. Remarkably, we demonstrate that ectopic expression of DNMT3L in hTSCs restores placental PMDs, supporting a conserved role for DNMT3L in de novo methylation in trophoblast development in human embryogenesis.
Humans↗
Identification of Glioblastoma Cell Surface Proteins and Assessment of Their Expression Across Patient-Derived Stem-Like Cell Cultures.
Glioblastoma (GBM) is the most common primary brain cancer in adults and remains fatal, with a median survival of a few months. There is an urgent need to develop novel therapeutic strategies against this aggressive malignancy. Modern cancer research increasingly focuses on personalized therapies tailored toward unique molecular features of each tumor or patient. In this context, cell surface proteins (CSPs) represent an attractive class of therapeutic targets due to their accessibility and central roles in physiological and pathological processes, making them among the most targeted proteins in current drug development. In this study, promising CSPs were identified through an untargeted proteomics approach using high-resolution mass spectrometry on patient-derived GBM stem-like cell (GSC) cultures, complemented by RNA-seq data and computational database analyses. From this primary discovery, five CSPs, namely PTK7, PTPRZ1, OSMR, CSPG4, and IGDCC4, were selected for detailed investigation. A targeted UHPLC-multiple reaction monitoring (MRM) method was developed and optimized to assess their expression and evaluate their abundance variations across different GSC cultures and cell passage levels. Beyond confirming these CSPs as potential therapeutic targets in GBM, our study demonstrates the value of three-dimensional GSC cultures as robust models for biomarker research and target assessment.
Humans↗
Single-cell spatial mapping reveals alteration of tissue microenvironment during early colorectal cancer.
Familial adenomatous polyposis (FAP) is a rare, hereditary syndrome that raises the risk of developing colorectal cancer (CRC). This disease model is well suited for studying the early stages of malignant transformation. Our spatial CODEX experiments reveal that, in contrast to normal mucosa, FAP mucosa, pre-cancer polyps and colorectal cancers exhibit substantial alterations in the cell type composition and tissue microenvironment. These early alterations include: an increase in the population of cancer-associated fibroblasts (CAFs), and the inhibition of tumor infiltrated lymphocytes and cell-adhesion protein by CAFs, the transformation of memory T cells into regulatory T cells, nuclear translocation of beta-catenin from the cell membrane, a decrease in the M1:M2 macrophage ratio, a notable increase in angiogenesis events. Our studies define the early stem cell, stromal, and immune steps of colorectal cancer and may benefit early detection, and therapeutic intervention.
Co-detection by Indexing (CODEX)↗
[Increased hematological toxicity of antineoplastic drugs with simultaneous androgenotherapy (author's transl)].
Thirty two patients with malignant lymphoma - mainly Hodgkin's disease - were randomized for simultaneous treatment by high doses of metenolone during MOPP chemotherapy, to reduce its hematological toxicity. The results have shown surprisingly an increased hemato-toxicity in patients receiving androgens, with significantly more marked anemia and thrombocytopenia, reducing the total doses of anti-cancer drugs. This side effect could be explained by a cycling of the hematopoietic stem-cells and call to some caution when androgens are used during cancer chemotherapy.
Androgens↗
Functional impact of cancer-associated cohesin variants on gene expression and cellular identity.
Cohesin is a ring-shaped protein complex that controls dynamic chromosome structure. Cohesin activity is important for a variety of biological processes, including formation of DNA loops that regulate gene expression. The precise mechanisms by which cohesin shapes local chromosome structure and gene expression are not fully understood. Recurrent mutations in cohesin complex members have been reported in various cancers, though it is not clear whether many cohesin sequence variants have phenotypes and contribute to disease. Here, we utilized CRISPR/Cas9 genome editing to introduce a variety of cohesin sequence variants into murine embryonic stem cells and investigate their molecular and cellular consequences. Some of the cohesin variants tested caused changes to transcription, including altered expression of gene encoding lineage-specifying developmental regulators. Altered gene expression was also observed at insulated neighborhoods, where cohesin-mediated DNA loops constrain potential interactions between genes and enhancers. Furthermore, some cohesin variants altered the proliferation rate and differentiation potential of murine embryonic stem cells. This study provides a functional comparison of cohesin variants found in cancer within an isogenic system, revealing the relative roles of various cohesin perturbations on gene expression and maintenance of cellular identity.
Animals↗
Thymic hormones.
The thymus produces several polypeptides, which induce lymphocyte differentiation in vitro and in vivo. Several of these polypeptides have been chemically characterized, and three of them have been sequenced and synthesised (alpha 1 thymosin, thymopoietin and the serum thymic factor). Thymic hormones do not act identically on all T-cell subsets: they alter preferentially post-thymic precursor cells, and among mature T cells cytotoxic cells and suppressor cells. Their mode of action at the cellular level involves binding to specific cellular receptors and interaction with adenyl cyclase. Preliminary clinical trials with crude extracts have provided promising results in immunodeficient and cancer patients. The differentiation of T cells from stem cells has been the matter of considerable investigation over the last two decades, since it has been realized that the thymus and its products, the thymus-derived cells (T cells) play a central role in the generation of effector cells in cell-mediated immunity and in the regulation of the various categories of immune responses. That the thymus could act by the intermediate of humoral substances was precociously suggested by MILLER and OSOBA before the observation that thymuses grafted within a cell-impermeable Millipore diffusion chamber restored the immunocompetence of neonatally thymectomized (Tx) mice (1). However, although this experiment was ultimately confirmed by using chambers with well-controlled impermeability (2), MILLER did not pursue the idea of the humoral function of the thymus. Probably, the striking results obtained by DAVIES (3) and other workers, indicating direct migration of functional T cells from the thymus and the poor results initially obtained in trying to reconstitute the immune system of neonatally Tx mice by cell-free thymic extracts contributed to this disappointment. A new impetus was given to the subject in the early 70's when in vitro tests of lymphocyte function became available and when purified extracts of the thymus proved capable of restoring antigen-specific and non-specific immunocompetence of Tx mice. More recently, completely defined synthetic thymic hormones have been obtained. The question is no longer to decide whether thymic hormones exist, but rather to elucidate their biological significance and potential clinical applications. The multiplicity of available factors has created some confusion. It will be the aim of these few pages to review critically the various factors reported in the literature, giving particular emphasis to their pharmacology and their potential use in the modulation of immune responses.
Carrier Proteins↗
Radiation injury: some aspects of the oncogenic effects.
The late effects or irradiation stem from cell killing, mutation, and malignant transformation. Cancer is the major somatic late effect of exposure to low dose levels of radiation, and estimates of risk of cancer in man after irradiation are based entirely on human experience. The data for dose-response relationships for the induction of tumors by external irradiation in man have been obtained from a single exposure or a small number of exposures delivered at high dose rates. In contrast, exposure to environmental irradiation is mainly protracted over a long period of time and is delivered at a low dose rate. As yet no allowance has been made for the effect of protraction of the exposure time in estimating the risk of cancer, although an adjustment has been made in the case of estimates of genetic risk. Incidence of tumors has been the only parameter used for risk estimates, but latent period and degree of malignancy, which are probably both dose and dose-rate dependent, influence the nature of the risk from radiation. As the knowledge about the effects of low-level radiation has been accumulated and assimilated over the last 70 years, so has the concern for reasonable standards of safety. There are still problems in the estimation of radiation risks, but at least many of the relevant questions can now be framed. The problems of estimating risks for chemical carcinogens are clearly greater, but the experience gained from radiation studies should help in the design of the necessary experiments.
Age Factors↗
DGKH-mediated phosphatidic acid oncometabolism as a driver of self-renewal and therapy resistance in HCC.
BACKGROUND AND AIMS: HCC is characterized by metabolic pathway aberrations, which enable cancer cells to meet their energy demands and accelerate malignant progression. Identifying novel metabolic players governing therapy resistance and self-renewal in HCC is crucial, as these properties are likely responsible for tumor recurrence. APPROACH AND RESULTS: Clinical traits and RNA-seq of patients with HCC in The Cancer Genome Atlas were used for weighted gene coexpression network analysis, where 1 module was significantly correlated with advanced pathological stage and stem cell population maintenance. Further analysis of this module by integrating data obtained from HCC patient nonresponders to tyrosine kinase inhibitors identified 361 commonly deregulated genes. Intriguingly, these genes are significantly enriched in the intracellular signal transduction pathway, with diacylglycerol kinase eta (DGKH) ranked as the most enriched gene in poorly differentiated HCC tumors. Clinically, DGKH was elevated in tumor tissues compared to nontumor tissues. Patients with higher DGKH expression exhibited a more undifferentiated state and were less responsive to tyrosine kinase inhibitors. Functional assays using DGKH-manipulated HCC cell lines demonstrated that DGKH augmented aggressive features, including cancer stemness, therapy resistance, and metastasis. Upstream of DGKH , we discovered that the E1A-associated protein p300 (EP300) binds to DGKH's promoter region, thereby increasing its transcriptomic expression. Mechanistically, DGKH promotes mTOR signaling by producing phosphatidic acid. In an immunocompetent mouse model, cotreatment with sorafenib and liver-directed AAV8-mediated Dgkh depletion significantly reduced tumor burden, self-renewal, phosphatidic acid production, and mTOR signaling. CONCLUSIONS: Our research demonstrated that DGKH is a crucial oncometabolic regulator of cancer stemness and therapy resistance, suggesting that inhibiting DGKH may lead to more effective HCC treatment.
Humans↗
Efficacy of MET-targeting CAR T cells against glioblastoma patient-derived xenograft models.
BACKGROUND: Genetic alteration of the MET receptor tyrosine kinase frequently occurs in glioblastoma (GBM). Clinically, bevacizumab treatment results in MET signaling activation, leading to GBM recurrence with a more malignant phenotype. While MET has been a promising therapeutic target, MET inhibitors have not been successful in treating GBM patients. MET-directed chimeric antigen receptor (CAR) T cells hold the promise of targeting MET-positive GBM regardless of genetic alterations or kinase activity. METHODS: GBM patient-derived xenografts (PDX) harboring MET amplification (METamp) or PTPRZ-MET fusion (ZM) were propagated in vivo followed by glioma stem cell (GSC) isolation. Cell-based assays were used for comparing GSC survival in response to MET inhibitors and CAR T cells. Multi-panel cytokine release was analyzed to profile MET-CAR T cell activation during co-culture with GBM. Orthotopic tumor growth and real-time imaging were performed to evaluate MET-CAR T cell therapeutic efficacy in vivo. RESULTS: Although GBM are heterogeneous tumors, neuro-sphere cells isolated from METamp or ZM fusion PDX tumors showed universal cognate genetic MET alteration along with GSC markers such as SOX2 and nestin. Both METamp and ZM fusion tumors showed MET overexpression but only the METamp cells presented activated MET signaling which was vulnerable to MET inhibitors. In contrast, MET-CAR T cells specifically inhibited all MET-positive tumor growth regardless of MET activation status. CONCLUSIONS: Whereas MET inhibitors are effective in MET-active tumors, MET-CAR T cells eradicate MET-positive GBM growth in an antigen-dependent manner, demonstrating a promising therapeutic approach for treating MET-positive GBM. MET overexpression, especially METamp and ZM fusion may be used to predefine the GBM patients for treating with MET-CAR T cell therapy.
Glioblastoma↗
Matrix Metalloprotease 1 (Mmp1) promotes cell fate change for epithelial-to-epithelial transition during regeneration after radiation damage in Drosophila.
Ionizing radiation (IR) is used to treat cancer, but therapeutic failure occurs when surviving cancer cells change fate and regenerate tumors through acquired stem cell-like properties. While transcriptional mechanisms underlying cell fate plasticity have been characterized, the cellular processes enabling cell movement during tissue regeneration remain unclear. We reported previously that hinge cells of the Drosophila larval wing disc convert to pouch fate and translocate to help regenerate the pouch that suffers from more IR-induced apoptosis. We report here that IR increases the expression of extracellular proteins in the hinge, including secreted proteases and cell adhesion modulators. Functional validation using RNA interference revealed that secreted Matrix Metalloprotease 1 (Mmp1) and the related secreted protease homolog Scarface (Scaf) are required in hinge cells for IR-induced cell fate conversion and translocation. IR, we found, induces Mmp1 and scaf transcripts in hinge cells via cell-autonomous JNK signaling. Overexpression of Mmp1 specifically in the hinge was sufficient to elevate Mmp1 protein levels throughout the disc and induced cell fate change of both hinge and non-hinge cells but only in the context of irradiation. Confocal imaging in a time course demonstrated that cells undergoing fate conversion remain within the epithelial layer with little evidence for delamination or epithelial-mesenchymal transition (EMT). We propose that remodeling of the extracellular environment is a critical mechanism that enables cellular reorganization during tissue regeneration. Mmp enzymes are important for cancer biology because of their role in ECM remodeling, extracellular signaling, and EMT. Our findings demonstrate for the first time that Mmp1 is necessary and sufficient for one epithelial cell type to switch to another epithelial cell type after radiation damage. These results provide a mechanistic basis for radiation therapy-induced cell fate plasticity.
Animals↗
DKK1-SE recruits AP1 to activate the target gene DKK1 thereby promoting pancreatic cancer progression.
Super-enhancers are a class of DNA cis-regulatory elements that can regulate cell identity, cell fate, stem cell pluripotency, and even tumorigenesis. Increasing evidence shows that epigenetic modifications play an important role in the pathogenesis of various types of cancer. However, the current research is far from enough to reveal the complex mechanism behind it. This study found a super-enhancer enriched with abnormally active histone modifications in pancreatic ductal adenocarcinoma (PDAC), called DKK1-super-enhancer (DKK1-SE). The major active component of DKK1-SE is component enhancer e1. Mechanistically, AP1 induces chromatin remodeling in component enhancer e1 and activates the transcriptional activity of DKK1. Moreover, DKK1 was closely related to the malignant clinical features of PDAC. Deletion or knockdown of DKK1-SE significantly inhibited the proliferation, colony formation, motility, migration, and invasion of PDAC cells in vitro, and these phenomena were partly mitigated upon rescuing DKK1 expression. In vivo, DKK1-SE deficiency not only inhibited tumor proliferation but also reduced the complexity of the tumor microenvironment. This study identifies that DKK1-SE drives DKK1 expression by recruiting AP1 transcription factors, exerting oncogenic effects in PDAC, and enhancing the complexity of the tumor microenvironment.
Humans↗