Suppression of NANOG Expression Reduces Drug Resistance of Cancer Stem Cells in Glioblastoma

Targeting cancer stem cells by TPA leads to inhibition of refractory sarcoma and extended overall survival

Refractory cancer recurrence in patients is a serious challenge in modern medicine. Tumor regrowth in a more aggressive and invasive drug-resistant form is caused by a specific sub-population of tumor cells defined as cancer stem cells (CSCs). While the role of CSCs in cancer relapse is recognized, the signaling pathways of CSCs-driven chemoresistance are less well understood. Moreover, there are no effective therapeutic strategies that involve specific inhibition of CSCs responsible for cancer recurrence and drug resistance. There is a clinical need to develop new therapies for patients with refractory sarcomas, particularly fibrosarcoma. These aggressive tumors, with poor overall survival, do not respond to conventional therapies. Standard systemic chemotherapy for these tumors includes doxorubicin (DOX). A Tyr peptide analog (TPA), developed in our laboratory, specifically targets CSCs by drastically reducing expression of the polycomb group protein enhancer of zester (EZH2) and its downstream targets, specifically ALDH1A1 and Nanog. In vivo experiments demonstrated that TPA inhibited tumor growth in nu/nu mice with relapsed DOX-treated fibrosarcoma 7-fold and led to improved overall (2-fold) survival. In an experimental metastatic model, the combination of TPA with DOX treatment extended overall survival 3-fold, suggesting that targeting CSC can become an effective strategy in the treatment of refractory/relapse fibrosarcoma.

Spatial metabolomics to discover hypertrophic scar relevant metabolic alterations and potential therapeutic strategies: A preliminary study

Spatially mapping the metabolic remodeling of hypertrophic scar and surrounding normal skin tissues has the potential to enhance our comprehension of scar formation and aid in the advancement of therapeutic interventions. In this study, we employed matrix-assisted laser desorption/ionization (MALDI), a mass spectrometry imaging technique, to visualize the hierarchical distribution of metabolites within sections of hypertrophic scar and surrounding normal skin tissues. A comprehensive analysis identified a total of 1631 metabolites in these tissues. The top four classes that were identified included benzene and substituted derivatives, heterocyclic compounds, amino acids and its metabolites, and glycerophospholipids. In hypertrophic scar tissues, 22 metabolites were upregulated and 66 metabolites were downregulated. MetaboAnalyst pathway analysis indicated that glycerophospholipid metabolism was primarily associated with these altered 88 metabolites. Subsequently, six metabolites were selected, their spatial characteristics were analyzed, and they were individually added to the cell culture medium of primary hypertrophic scar fibroblasts. The preliminary findings of this study demonstrate that specific concentrations of 1-pyrrolidinecarboxamide, 2-benzylideneheptanal, glycerol trioleate, Lyso-PAF C-16, and moxonidine effectively inhibited the expressions of COL1A1, COL1A2, COL3A1, and ACTA2. These bioactive metabolites exhibit mild and non-toxic properties, along with favorable pharmacokinetics and pharmacodynamics, making them promising candidates for drug development. Consequently, this research offers novel therapeutic insights for hypertrophic scar treatment.

Characterizing CD133 and NANOG Expression in Melanoma: Associations with Histological and Epidemiological Parameters

Background/Objectives: Melanoma is an aggressive skin malignancy, and the majority of deaths associated with melanoma result from malignant skin lesions. Our study aims to evaluate the expression of the markers CD133 and NANOG, associated with tumor stem cells, and to analyze their link with epidemiological and histological parameters, thus contributing to early diagnosis and the development of targeted therapies. Methods: We performed a retrospective study in the Mureș Clinical County Hospital, Romania, which included 66 cases of melanoma: 50 primary cutaneous melanomas, 10 metastases, and 6 local recurrences. CD133 and NANOG marker expression was assessed by immunohistochemistry and quantified using the H score. Statistical analyses were applied to determine the correlations between marker expression and clinicopathological parameters. Results: CD133 expression was identified in six cases (12%) of primary melanoma, with a mean H-Score of 29, and was associated with an increased Breslow index and a higher number of mitoses. NANOG expression was positive in 30 cases (60%) of primary melanoma, with a median H-Score of 15 and with increased expression observed in cases with pagetoid migration and lesions in situ. In metastases, eight cases (80%) were positive for NANOG and four (40%) for CD133. Local recurrences showed positive expression for NANOG in four cases (66%). Conclusions: The expression of CD133 and NANOG markers highlights the role of tumor stem cells in melanoma progression. Early identification of these markers could improve diagnosis and treatment, including the application of targeted therapies.

Combined inhibition of EZH2 and CDK4/6 perturbs endoplasmic reticulum-mitochondrial homeostasis and increases antitumor activity against glioblastoma

He, we show that combined use of the EZH2 inhibitor GSK126 and the CDK4/6 inhibitor abemaciclib synergistically enhances antitumoral effects in preclinical GBM models. Dual blockade led to HIF1α upregulation and CalR translocation, accompanied by massive impairment of mitochondrial function. Basal oxygen consumption rate, ATP synthesis, and maximal mitochondrial respiration decreased, confirming disrupted endoplasmic reticulum-mitochondrial homeostasis. This was paralleled by mitochondrial depolarization and upregulation of the UPR sensors PERK, ATF6α, and IRE1α. Notably, dual EZH2/CDK4/6 blockade also reduced 3D-spheroid invasion, partially inhibited tumor growth in ovo, and led to impaired viability of patient-derived organoids. Mechanistically, this was due to transcriptional changes in genes involved in mitotic aberrations/spindle assembly (Rb, PLK1, RRM2, PRC1, CENPF, TPX2), histone modification (HIST1H1B, HIST1H3G), DNA damage/replication stress events (TOP2A, ATF4), immuno-oncology (DEPDC1), EMT-counterregulation (PCDH1) and a shift in the stemness profile towards a more differentiated state. We propose a dual EZH2/CDK4/6 blockade for further investigation.

Deciphering the role of transcription factors in glioblastoma cancer stem cells

Glioblastoma (GBM), the most aggressive and fatal brain malignancy, is largely driven by a subset of tumor cells known as cancer stem cells (CSCs). CSCs possess stem cell-like properties, including self-renewal, proliferation, and differentiation, making them pivotal for tumor initiation, invasion, metastasis, and overall tumor progression. The regulation of CSCs is primarily controlled by transcription factors (TFs) which regulate the expressions of genes involved in maintaining stemness and directing differentiation. This review aims to provide a comprehensive overview of the role of TFs in regulating CSCs in GBM. The discussion encompasses the definitions of CSCs and TFs, the significance of glioma stem cells (GSCs) in GBM, and how TFs regulate GSC self-renewal, proliferation, differentiation, and transformation. The potential for developing TF-targeted GSC therapies is also explored, along with future research directions. By understanding the regulation of GSCs by TFs, we may uncover novel diagnostic and therapeutic strategies against this devastating disease of GBM.

Hypoxia effects on glioblastoma progression through YAP/TAZ pathway regulation

The resistance of glioblastomas (GBM) to standard therapies poses a clinical challenge with limited survival despite interventions. The tumor microenvironment (TME) orchestrates GBM progression, comprising stromal and immune cells and is characterized by extensive hypoxic regions. Hypoxia activates the hypoxia-inducible factor 1 alpha (HIF-1α) pathway, interacting with the Hippo pathway (YAP/TAZ) in crucial cellular processes. We discuss here the related signaling crosstalk between YAP/TAZ and regions of hypoxia in the TME with particular attention on the MST1/2 and LATS1/2-regulated YAP/TAZ activation, impacting cell proliferation, invasion, and stemness. Moreover, the hypoxia-YAP/TAZ axis influence on angiogenesis, stem cells, and metabolic regulators is defined. By reviewing extracellular matrix alterations activation of YAP/TAZ, modulation of signaling pathways we also discuss the significance of spatial constraints and epigenetic modifications contribution to GBM progression, with potential therapeutic targets in YAP/TAZ-mediated gene regulation. Comprehensive understanding of the hypoxia-Hippo pathway-TME interplay offers insights for novel therapeutic strategies, aiming to provide new directions for treatment.

Dualistic Effects of PRKAR1A as a Potential Anticancer Target in Cancer Cells and Cancer-Derived Stem Cells

The integration of innovative medical technologies and interdisciplinary collaboration could improve the treatment of cancer, a globally prevalent and often deadly disease. Despite recent advancements, current cancer therapies fail to specifically address recurrence and target cancer stem cells (CSCs), which contribute to relapse. In this study, we utilized three types of cancer cells, from which three types of CSCs were further derived, to conduct a proteomic analysis. Additionally, shared cell surface biomarkers were identified as potential targets for a comprehensive treatment strategy. The selected biomarkers were evaluated through short hairpin RNA treatment, which revealed contrasting functions in cancer cells and CSCs. Knockdown of the identified proteins revealed that they regulate the epithelial-mesenchymal transition (EMT) and stemness via the ERK signaling pathway. Resistance to anticancer agents was consequently reduced, ultimately enhancing the overall anticancer effects of the treatment. Additionally, the significance of these biomarkers in clinical patient outcomes was confirmed using bioinformatics. Our study suggests a novel cancer treatment strategy that addresses the limitations of current anticancer therapies.

Mechanical Constraints in Tumor Guide Emergent Spatial Patterns of Glioblastoma Cancer Stem Cells

The mechanical constraints in the overcrowding glioblastoma (GBM) microenvironment have been implicated in the regulation of tumor heterogeneity and disease progression. Especially, such mechanical cues can alter cellular DNA transcription and give rise to a subpopulation of tumor cells called cancer stem cells (CSCs). These CSCs with stem-like properties are critical drivers of tumorigenesis, metastasis, and treatment resistance. Yet, the biophysical and molecular machinery underlying the emergence of CSCs in tumor remained unexplored. This work employed a two-dimensional micropatterned multicellular model to examine the impact of mechanical constraints arisen from geometric confinement on the emergence and spatial patterning of CSCs in GBM tumor. Our study identified distinct spatial distributions of GBM CSCs in different geometric patterns, where CSCs mostly emerged in the peripheral regions. The spatial pattern of CSCs was found to correspond to the gradients of mechanical stresses resulted from the interplay between the cell-ECM and cell-cell interactions within the confined environment. Further mechanistic study highlighted a Piezo1-RhoA-focal adhesion signaling axis in regulating GBM cell mechanosensing and the subsequent CSC phenotypic transformation. These findings provide new insights into the biophysical origin of the unique spatial pattern of CSCs in GBM tumor and offer potential avenues for targeted therapeutic interventions.