Imp2 controls oxidative phosphorylation and is crucial for preserving glioblastoma cancer stem cells

PCK1 attenuates tumor stemness via activating the Hippo signaling pathway in hepatocellular carcinoma

Liver cancer stem cells were found to rely on glycolysis as the preferred metabolic program. Phosphoenolpyruvate carboxylase 1 (PCK1), a gluconeogenic metabolic enzyme, is down-regulated in hepatocellular carcinoma and is closely related to poor prognosis. The oncogenesis and progression of tumors are closely related to cancer stem cells. It is not completely clear whether the PCK1 deficiency increases the stemness of hepatoma cells and promotes the oncogenesis of hepatocellular carcinoma. Herein, the results showed that PCK1 inhibited the self-renewal property of hepatoma cells, reduced the mRNA level of cancer stem cell markers, and inhibited tumorigenesis. Moreover, PCK1 increased the sensitivity of hepatocellular carcinoma cells to sorafenib. Furthermore, we found that PCK1 activated the Hippo pathway by enhancing the phosphorylation of YAP and inhibiting its nuclear translocation. Verteporfin reduced the stemness of hepatoma cells and promoted the pro-apoptotic effect of sorafenib. Thus, combined treatment with verteporfin and sorafenib may be a potential anti-tumor strategy in hepatocellular carcinoma.

Metabolic dysregulation of tricarboxylic acid cycle and oxidative phosphorylation in glioblastoma

Glioblastoma multiforme (GBM) exhibits genetic alterations that induce the deregulation of oncogenic pathways, thus promoting metabolic adaptation. The modulation of metabolic enzyme activities is necessary to generate nucleotides, amino acids, and fatty acids, which provide energy and metabolic intermediates essential for fulfilling the biosynthetic needs of glioma cells. Moreover, the TCA cycle produces intermediates that play important roles in the metabolism of glucose, fatty acids, or non-essential amino acids, and act as signaling molecules associated with the activation of oncogenic pathways, transcriptional changes, and epigenetic modifications. In this review, we aim to explore how dysregulated metabolic enzymes from the TCA cycle and oxidative phosphorylation, along with their metabolites, modulate both catabolic and anabolic metabolic pathways, as well as pro-oncogenic signaling pathways, transcriptional changes, and epigenetic modifications in GBM cells, contributing to the formation, survival, growth, and invasion of glioma cells. Additionally, we discuss promising therapeutic strategies targeting key players in metabolic regulation. Therefore, understanding metabolic reprogramming is necessary to fully comprehend the biology of malignant gliomas and significantly improve patient survival.

Metabolic dependencies of acute myeloid leukemia stem cells

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy primarily driven by an immature population of AML cells termed leukemia stem cells (LSCs) that are implicated in AML development, chemoresistance, and relapse. An emerging area of research in AML focuses on identifying and targeting the aberrant metabolism in LSCs. Dysregulated metabolism is involved in sustaining functional properties of LSCs, impeding myeloid differentiation, and evading programmed cell death, both in the process of leukemogenesis and in response to chemotherapy. This review discusses recent discoveries regarding the aberrant metabolic processes of AML LSCs that have begun to change the therapeutic landscape of AML.

METTL8 links mt-tRNA m3C modification to the HIF1α/RTK/Akt axis to sustain GBM stemness and tumorigenicity

Epitranscriptomic RNA modifications are crucial for the maintenance of glioma stem cells (GSCs), the most malignant cells in glioblastoma (GBM). 3-methylcytosine (m3C) is a new epitranscriptomic mark on RNAs and METTL8 represents an m3C writer that is dysregulated in cancer. Although METTL8 has an established function in mitochondrial tRNA (mt-tRNA) m3C modification, alternative splicing of METTL8 can also generate isoforms that localize to the nucleolus where they may regulate R-loop formation. The molecular basis for METTL8 dysregulation in GBM, and which METTL8 isoform(s) may influence GBM cell fate and malignancy remain elusive. Here, we investigated the role of METTL8 in regulating GBM stemness and tumorigenicity. In GSC, METTL8 is exclusively localized to the mitochondrial matrix where it installs m3C on mt-tRNAThr/Ser(UCN) for mitochondrial translation and respiration. High expression of METTL8 in GBM is attributed to histone variant H2AZ-mediated chromatin accessibility of HIF1α and portends inferior glioma patient outcome. METTL8 depletion impairs the ability of GSC to self-renew and differentiate, thus retarding tumor growth in an intracranial GBM xenograft model. Interestingly, METTL8 depletion decreases protein levels of HIF1α, which serves as a transcription factor for several receptor tyrosine kinase (RTK) genes, in GSC. Accordingly, METTL8 loss inactivates the RTK/Akt axis leading to heightened sensitivity to Akt inhibitor treatment. These mechanistic findings, along with the intimate link between METTL8 levels and the HIF1α/RTK/Akt axis in glioma patients, guided us to propose a HIF1α/Akt inhibitor combination which potently compromises GSC proliferation/self-renewal in vitro. Thus, METTL8 represents a new GBM dependency that is therapeutically targetable.

Integrative analysis of transcriptome and proteome profiles in primary and recurrent glioblastoma

PURPOSE

Glioblastoma (GBM) is the most common and aggressive primary brain tumor characterized by poor prognosis and high recurrence. The underlying molecular mechanism that drives tumor progression and recurrence is unclear. This study is intended to look for molecular and biological changes that play a key role in GBM recurrence.

EXPERIMENTAL DESIGN

An integrative transcriptomic and proteomic analysis was performed on three primary GBM and three recurrent GBM tissues. Omics analyses were conducted using label-free quantitative proteomics and whole transcriptome sequencing.

RESULTS

A significant difference was found between primary GBM and recurrent GBM at the transcriptional level. Similar to other omics studies of cancer, a weak overlap was observed between transcriptome and proteome, and Procollagen C-Endopeptidase Enhancer 2 (PCOLCE2) was observed to be upregulated at mRNA and protein levels. Analysis of public cancer database revealed that high expression of PCOLCE2 is associated with poor prognosis of patients with GBM and that it may be a potential prognostic indicator. Functional and environmental enrichment analyses revealed significantly altered signaling pathways related to energy metabolism, including mitochondrial ATP synthesis-coupled electron transport and oxidative phosphorylation.

CONCLUSIONS AND CLINICAL RELEVANCE

This study provides new insights into the recurrence process of GBM through combined transcriptomic and proteomic analyses, complementing the existing GBM transcriptomic and proteomic data and suggesting that integrated multi-omics analyses may reveal new disease features of GBM.

Bioactive compounds from Morchella esculenta as potential inhibitors of RNA-binding protein La in ovarian cancer: a molecular modeling and quantum mechanics approach

La protein is significantly expressed in various malignant tumors, including ovarian cancer (OC), which is related to the poor response to platinum-based chemotherapy. Thus, inhibiting La protein could control the expression of the potential downstream genes involved in promoting proliferation and chemotherapy resistance to OC, which could serve as a therapeutic intervention. Through a molecular docking approach, 12 compounds from Morchella esculenta were screened against the crystal structure of La protein and four hit compounds were identified, including beta-carotene, p-hydroxybenzoic acid, gamma-tocopherol, and alpha-tocopherol, with a binding affinity of - 10.7, - 8.1, - 7.9, and - 7.6 kcal/mol, respectively, higher than pyridine-2-carboxylate (control), with a binding affinity of - 5.2 kcal/mol. To explore the interaction of the hit compounds with the target receptor, they were selected for a molecular dynamic simulation and post-simulation analysis for 100 ns. The result showed promising reliability of the ligands due to a stable interaction with the La protein crystal structure. Furthermore, the drug-likeness and physicochemical chemical properties of the compounds were investigated using ADMET study and density functional theory analysis, respectively, and the result shows that the hit compounds could serve as a promising starting for the development of novel LA protein inhibitors for OC therapeutics. Finally, this study compared HOMO and LUMO values from global hybrids with long-range corrected DFAs, and the result from the two followed the same qualitative pattern while calculating HOMO values; however, MO62X/cc-pVTZ could better predict LUMO values when considering a global hybrid.

Cancer resistance and metastasis are maintained through oxidative phosphorylation

Malignant tumors have increased energy requirements due to growth, differentiation or response to stress. A significant number of studies in recent years have described upregulation of mitochondrial genes responsible for oxidative phosphorylation (OXPHOS) in some tumors. Although OXPHOS is replaced by glycolysis in some tumors (Warburg effect), both processes can occur simultaneously during the evolution of the same malignancies. In particular, chemoresistant and/or cancer stem cells appear to find a way to activate OXPHOS and metastasize. In this paper, we discuss recent work showing upregulation of OXPHOS in chemoresistant tumors and cell models. In addition, we show an inverse correlation of OXPHOS gene expression with the survival time of cancer patients after chemotherapy and discuss combination therapies for resistant tumors.

The MDM2-p53 Axis Represents a Therapeutic Vulnerability Unique to Glioma Stem Cells

The prevention of tumor recurrence by the successful targeting of glioma stem cells endowed with a tumor-initiating capacity is deemed the key to the long-term survival of glioblastoma patients. Glioma stem cells are characterized by their marked therapeutic resistance; however, recent evidence suggests that they have unique vulnerabilities that may be therapeutically targeted. We investigated MDM2 expression levels in glioma stem cells and their non-stem cell counterparts and the effects of the genetic and pharmacological inhibition of MDM2 on the viability of these cells as well as downstream molecular pathways. The results obtained showed that MDM2 expression was substantially higher in glioma stem cells than in their non-stem cell counterparts and also that the inhibition of MDM2, either genetically or pharmacologically, induced a more pronounced activation of the p53 pathway and apoptotic cell death in the former than in the latter. Specifically, the inhibition of MDM2 caused a p53-dependent increase in the expression of BAX and PUMA and a decrease in the expression of survivin, both of which significantly contributed to the apoptotic death of glioma stem cells. The present study identified the MDM2-p53 axis as a novel therapeutic vulnerability, or an Achilles' heel, which is unique to glioma stem cells. Our results, which suggest that non-stem, bulk tumor cells are less sensitive to MDM2 inhibitors, may help guide the selection of glioblastoma patients suitable for MDM2 inhibitor therapy.

Glioblastoma stem cell metabolism and immunity

Despite enormous efforts being invested in the development of novel therapies for brain malignancies, there remains a dire need for effective treatments, particularly for pediatric glioblastomas. Their poor prognosis has been attributed to the fact that conventional therapies target tumoral cells, but not glioblastoma stem cells (GSCs). GSCs are characterized by self-renewal, tumorigenicity, poor differentiation, and resistance to therapy. These characteristics represent the fundamental tools needed to recapitulate the tumor and result in a relapse. The mechanisms by which GSCs alter metabolic cues and escape elimination by immune cells are discussed in this article, along with potential strategies to harness effector immune cells against GSCs. As cellular immunotherapy is making significant advances in a variety of cancers, leveraging this underexplored reservoir may result in significant improvements in the treatment options for brain malignancies.

Unraveling the intricacies of glioblastoma progression and recurrence: insights into the role of NFYB and oxidative phosphorylation at the single-cell level

Background

Glioblastoma (GBM), with its high recurrence and mortality rates, makes it the deadliest neurological malignancy. Oxidative phosphorylation is a highly active cellular pathway in GBM, and NFYB is a tumor-associated transcription factor. Both are related to mitochondrial function, but studies on their relationship with GBM at the single-cell level are still scarce.

Methods

We re-analyzed the single-cell profiles of GBM from patients with different subtypes by single-cell transcriptomic analysis and further subdivided the large population of Glioma cells into different subpopulations, explored the interrelationships and active pathways among cell stages and clinical subtypes of the populations, and investigated the relationship between the transcription factor NFYB of the key subpopulations and GBM, searching for the prognostic genes of GBM related to NFYB, and verified by experiments.

Results

Glioma cells and their C5 subpopulation had the highest percentage of G2M staging and rGBM, which we hypothesized might be related to the higher dividing and proliferating ability of both Glioma and C5 subpopulations. Oxidative phosphorylation pathway activity is elevated in both the Glioma and C5 subgroup, and NFYB is a key transcription factor for the C5 subgroup, suggesting its possible involvement in GBM proliferation and recurrence, and its close association with mitochondrial function. We also identified 13 prognostic genes associated with NFYB, of which MEM60 may cause GBM patients to have a poor prognosis by promoting GBM proliferation and drug resistance. Knockdown of the NFYB was found to contribute to the inhibition of proliferation, invasion, and migration of GBM cells.

Conclusion

These findings help to elucidate the key mechanisms of mitochondrial function in GBM progression and recurrence, and to establish a new prognostic model and therapeutic target based on NFYB.

IGF2BPs as novel m6A readers: Diverse roles in regulating cancer cell biological functions, hypoxia adaptation, metabolism, and immunosuppressive tumor microenvironment

m6A methylation is the most frequent modification of mRNA in eukaryotes and plays a crucial role in cancer progression by regulating biological functions. Insulin-like growth factor 2 mRNA-binding proteins (IGF2BP) are newly identified m6A 'readers'. They belong to a family of RNA-binding proteins, which bind to the m6A sites on different RNA sequences and stabilize them to promote cancer progression. In this review, we summarize the mechanisms by which different upstream factors regulate IGF2BP in cancer. The current literature analyzed here reveals that the IGF2BP family proteins promote cancer cell proliferation, survival, and chemoresistance, inhibit apoptosis, and are also associated with cancer glycolysis, angiogenesis, and the immune response in the tumor microenvironment. Therefore, with the discovery of their role as 'readers' of m6A and the characteristic re-expression of IGF2BPs in cancers, it is important to elucidate their mechanism of action in the immunosuppressive tumor microenvironment. We also describe in detail the regulatory and interaction network of the IGF2BP family in downstream target RNAs and discuss their potential clinical applications as diagnostic and prognostic markers, as well as recent advances in IGF2BP biology and associated therapeutic value.

Structural insights into IMP2 dimerization and RNA binding

IGF2BP2 (IMP2) is an RNA-binding protein that contributes to cancer tumorigenesis and metabolic disorders. Structural studies focused on individual IMP2 domains have provided important mechanistic insights into IMP2 function; however, structural information on full-length IMP2 is lacking but necessary to understand how to target IMP2 activity in drug discovery. In this study, we investigated the behavior of full-length IMP2 and the influence of RNA binding using biophysical and structural methods including mass photometry, hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS), and small angle x-ray scattering (SAXS). We found that full-length IMP2 forms multiple oligomeric states but predominantly adopts a dimeric conformation. Molecular models derived from SAXS data suggest the dimer is formed in a head-to-tail orientation by the KH34 and RRM1 domains. Upon RNA binding, IMP2 forms a pseudo-symmetric dimer different from its apo/RNA-free state, with the KH12 domains of each IMP2 molecule forming the dimer interface. We also found that the formation of IMP2 oligomeric species, which includes dimers and higher-order oligomers, is sensitive to ionic strength and RNA binding. Our findings provide the first insight into the structural properties of full-length IMP2, which may lead to novel opportunities for disrupting its function with more effective IMP2 inhibitors.

Gene regulatory network topology governs resistance and treatment escape in glioma stem-like cells

Poor prognosis and drug resistance in glioblastoma (GBM) can result from cellular heterogeneity and treatment-induced shifts in phenotypic states of tumor cells, including dedifferentiation into glioma stem-like cells (GSCs). This rare tumorigenic cell subpopulation resists temozolomide, undergoes proneural-to-mesenchymal transition (PMT) to evade therapy, and drives recurrence. Through inference of transcriptional regulatory networks (TRNs) of patient-derived GSCs (PD-GSCs) at single-cell resolution, we demonstrate how the topology of transcription factor interaction networks drives distinct trajectories of cell state transitions in PD-GSCs resistant or susceptible to cytotoxic drug treatment. By experimentally testing predictions based on TRN simulations, we show that drug treatment drives surviving PD-GSCs along a trajectory of intermediate states, exposing vulnerability to potentiated killing by siRNA or a second drug targeting treatment-induced transcriptional programs governing non-genetic cell plasticity. Our findings demonstrate an approach to uncover TRN topology and use it to rationally predict combinatorial treatments that disrupts acquired resistance in GBM.

Ribogenesis boosts controlled by HEATR1-MYC interplay promote transition into brain tumour growth

Cell commitment to tumourigenesis and the onset of uncontrolled growth are critical determinants in cancer development but the early events directing tumour initiating cell (TIC) fate remain unclear. We reveal a single-cell transcriptome profile of brain TICs transitioning into tumour growth using the brain tumour (brat) neural stem cell-based Drosophila model. Prominent changes in metabolic and proteostasis-associated processes including ribogenesis are identified. Increased ribogenesis is a known cell adaptation in established tumours. Here we propose that brain TICs boost ribogenesis prior to tumour growth. In brat-deficient TICs, we show that this dramatic change is mediated by upregulated HEAT-Repeat Containing 1 (HEATR1) to promote ribosomal RNA generation, TIC enlargement and onset of overgrowth. High HEATR1 expression correlates with poor glioma patient survival and patient-derived glioblastoma stem cells rely on HEATR1 for enhanced ribogenesis and tumourigenic potential. Finally, we show that HEATR1 binds the master growth regulator MYC, promotes its nucleolar localisation and appears required for MYC-driven ribogenesis, suggesting a mechanism co-opted in ribogenesis reprogramming during early brain TIC development.

A glimpse into let-7e roles in human disorders; friend or foe?

MicroRNAs (miRNAs) have been linked to abnormal expression and regulation in a number of diseases, including cancer. Recent studies have concentrated on miRNA Let-7e's significance in precision medicine for cancer screening and diagnosis as well as its prognostic and therapeutic potential. Differential let-7e levels in bodily fluids have the possibility to enable early detection of cancer utilizing less-invasive techniques, reducing biopsy-related risks. Although Let-7e miRNAs have been described as tumor suppressors, it is crucial to note that there exists proof to support their oncogenic activity in vitro and in in vivo. Let-7e's significance in chemo- and radiation treatment decisions has also been demonstrated. Let-7e can also prevent the synthesis of proinflammatory cytokines in a number of degenerative disorders, including musculoskeletal and neurological conditions. For the first time, an overview of the significance of let-7e in the prevention, detection, and therapy of cancer and other conditions has been given in the current review. Additionally, we focused on the specific molecular processes that underlie the actions of let-7e, more particularly, on malignant cells.

Predominant factors influencing reactive oxygen species in cancer stem cells

Reactive oxygen species (ROS) and its related signaling pathways and regulating molecules play a major role in the growth and development of cancer stem cells. The concept of ROS and cancer stem cells (CSCs) has been gaining much attention since the past decade and the evidence show that these CSCs possess robust self-renewal and tumorigenic potential and are resistant to conventional chemo- and radiotherapy and believed to be responsible for tumor progression, metastasis, and recurrence. It seems reasonable to say that cancer can be cured only if the CSCs are eradicated. ROS are Janus-faced molecules that can regulate cellular physiology as well as induce cytotoxicity, depending on the magnitude, duration, and site of generation. Unlike normal cancer cells, CSCs expel ROS efficiently by upregulating ROS scavengers. This unique redox regulation in CSCs protects them from ROS-mediated cell death and nullifies the effect of radiation, leading to chemoresistance and radioresistance. However, how these CSCs control ROS production by scavenging free radicals and how they maintain low levels of ROS is a challenging to understand and these attributes make CSCs as prime therapeutic targets. Here, we summarize the mechanisms of redox regulation in CSCs, with a focus on therapy resistance, its various pathways and microRNAs regulation, and the potential therapeutic implications of manipulating the ROS levels to eradicate CSCs. A better understanding of these molecules, their interactions in the CSCs may help us to adopt proper control and treatment measures.

Cancer stem cells: a target for overcoming therapeutic resistance and relapse

Cancer stem cells (CSCs) are a small subset of cells in cancers that are thought to initiate tumorous transformation and promote metastasis, recurrence, and resistance to treatment. Growing evidence has revealed the existence of CSCs in various types of cancers and suggested that CSCs differentiate into diverse lineage cells that contribute to tumor progression. We may be able to overcome the limitations of cancer treatment with a comprehensive understanding of the biological features and mechanisms underlying therapeutic resistance in CSCs. This review provides an overview of the properties, biomarkers, and mechanisms of resistance shown by CSCs. Recent findings on metabolic features, especially fatty acid metabolism and ferroptosis in CSCs, are highlighted, along with promising targeting strategies. Targeting CSCs is a potential treatment plan to conquer cancer and prevent resistance and relapse in cancer treatment.

Exploring Lin28 proteins: Unravelling structure and functions with emphasis on nervous system malignancies

Cancer and stem cells share many characteristics related to self-renewal and differentiation. Both cell types express the same critical proteins that govern cellular stemness, which provide cancer cells with the growth and survival benefits of stem cells. LIN28 is an example of one such protein. LIN28 includes two main isoforms, LIN28A and LIN28B, with diverse physiological functions from tissue development to control of pluripotency. In addition to their physiological roles, LIN28A and LIN28B affect the progression of several cancers by regulating multiple cancer hallmarks. Altered expression levels of LIN28A and LIN28B have been proposed as diagnostic and/or prognostic markers for various malignancies. This review discusses the structure and modes of action of the different LIN28 proteins and examines their roles in regulating cancer hallmarks with a focus on malignancies of the nervous system. This review also highlights some gaps in the field that require further exploration to assess the potential of targeting LIN28 proteins for controlling cancer.

Sniping Cancer Stem Cells with Nanomaterials

Cancer stem cells (CSCs) drive tumor initiation, progression, and therapeutic resistance due to their self-renewal and differentiation capabilities. Despite encouraging progress in cancer treatment, conventional approaches often fail to eliminate CSCs, necessitating the development of precise targeted strategies. Recent advances in materials science and nanotechnology have enabled promising CSC-targeted approaches, harnessing the power of tailoring nanomaterials in diverse therapeutic applications. This review provides an update on the current landscape of nanobased precision targeting approaches against CSCs. We elucidate the nuanced application of organic, inorganic, and bioinspired nanomaterials across a spectrum of therapeutic paradigms, encompassing targeted therapy, immunotherapy, and multimodal synergistic therapies. By examining the accomplishments and challenges in this potential field, we aim to inform future efforts to advance nanomaterial-based therapies toward more effective "sniping" of CSCs and tumor clearance.

Role of N6-methyladenosine methylation in glioma: recent insights and future directions

Glioma is the most pervasive intracranial tumor in the central nervous system (CNS), with glioblastoma (GBM) being the most malignant type having a highly heterogeneous cancer cell population. There is a significantly high mortality rate in GBM patients. Molecular biomarkers related to GBM malignancy may have prognostic values in predicting survival outcomes and therapeutic responses, especially in patients with high-grade gliomas. In particular, N6-methyladenine (m6A) mRNA modification is the most abundant form of post-transcriptional RNA modification in mammals and is involved in regulating mRNA translation and degradation. Cumulative findings indicate that m6A methylation plays a crucial part in neurogenesis and glioma pathogenesis. In this review, we summarize recent advances regarding the functional significance of m6A modification and its regulatory factors in glioma occurrence and progression. Significant advancement of m6A methylation-associated regulators as potential therapeutic targets is also discussed.

RNA binding protein IGF2BP2 expression is induced by stress in the heart and mediates dilated cardiomyopathy

The IGF2BP family of RNA binding proteins consists of three paralogs that regulate intracellular RNA localization, RNA stability, and translational control. Although IGF2BP1 and 3 are oncofetal proteins, IGF2BP2 expression is maintained in many tissues, including the heart, into adulthood. IGF2BP2 is upregulated in cardiomyocytes during cardiac stress and remodeling and returns to normal levels in recovering hearts. We wondered whether IGF2BP2 might play an adaptive role during cardiac stress and recovery. Enhanced expression of an IGF2BP2 transgene in a conditional, inducible mouse line leads to dilated cardiomyopathy (DCM) and death within 3-4 weeks in newborn or adult hearts. Downregulation of the transgene after 2 weeks, however, rescues these mice, with complete recovery by 12 weeks. Hearts overexpressing IGF2BP2 downregulate sarcomeric and mitochondrial proteins and have fragmented mitochondria and elongated, thinner sarcomeres. IGF2BP2 is also upregulated in DCM or myocardial infarction patients. These results suggest that IGF2BP2 may be an attractive target for therapeutic intervention in cardiomyopathies.

Metabolic Profiles of Cancer Stem Cells and Normal Stem Cells and Their Therapeutic Significance

Cancer stem cells (CSCs) are a rare cancer cell population, responsible for the facilitation, progression, and resistance of tumors to therapeutic interventions. This subset of cancer cells with stemness and tumorigenic properties is organized in niches within the tumor microenvironment (TME) and presents altered regulation in a variety of metabolic pathways, including glycolysis, oxidative phosphorylation (OXPHOS), as well as lipid, amino acid, and iron metabolism. CSCs exhibit similarities as well as differences when comparedto normal stem cells, but also possess the ability of metabolic plasticity. In this review, we summarize the metabolic characteristics of normal, non-cancerous stem cells and CSCs. We also highlight the significance and implications of interventions targeting CSC metabolism to potentially achieve more robust clinical responses in the future.

The STEMRI trial: Magnetic resonance spectroscopy imaging can define tumor areas enriched in glioblastoma stem-like cells

Despite maximally safe resection of the magnetic resonance imaging (MRI)-defined contrast-enhanced (CE) central tumor area and chemoradiotherapy, most patients with glioblastoma (GBM) relapse within a year in peritumoral FLAIR regions. Magnetic resonance spectroscopy imaging (MRSI) can discriminate metabolic tumor areas with higher recurrence potential as CNI+ regions (choline/N-acetyl-aspartate index >2) can predict relapse sites. As relapses are mainly imputed to glioblastoma stem-like cells (GSCs), CNI+ areas might be GSC enriched. In this prospective trial, 16 patients with GBM underwent MRSI/MRI before surgery/chemoradiotherapy to investigate GSC content in CNI-/+ biopsies from CE/FLAIR. Biopsy and derived-GSC characterization revealed a FLAIR/CNI+ sample enrichment in GSC and in gene signatures related to stemness, DNA repair, adhesion/migration, and mitochondrial bioenergetics. FLAIR/CNI+ samples generate GSC-enriched neurospheres faster than FLAIR/CNI-. Parameters assessing biopsy GSC content and time-to-neurosphere formation in FLAIR/CNI+ were associated with worse patient outcome. Preoperative MRI/MRSI would certainly allow better resection and targeting of FLAIR/CNI+ areas, as their GSC enrichment can predict worse outcomes.

BEX1 supports the stemness of hepatoblastoma by facilitating Warburg effect in a PPARγ/PDK1 dependent manner

BACKGROUND

Hepatoblastoma (HB) is a highly aggressive paediatric malignancy that exhibits a high presence of cancer stem cells (CSCs), which related to tumour recurrence and chemotherapy resistance. Brain expressed X-linked protein 1 (BEX1) plays a pivotal role in ciliogenesis, axon regeneration and differentiation of neural stem cells. However, the role of BEX1 in metabolic and stemness programs in HB remains unclear.

METHODS

BEX1 expression in human and mouse HB was analyzed using gene expression profile data from NCBI GEO and immunohistochemical validation. Seahorse extracellular flux analyzer, ultra-high-performance liquid-chromatography mass spectrometry (LC-MS), flow cytometry, qRT-PCR, Western Blot, sphere formation assay, and diluted xenograft tumour formation assay were used to analyze metabolic and stemness features.

RESULTS

Our results indicated that overexpression of BEX1 significantly enhanced the Warburg effect in HB cells. Furthermore, glycolysis inhibition largely attenuated the effects of BEX1 on HB cell growth and self-renewal, suggesting that BEX1 promotes stemness maintenance of HB cells by regulating the Warburg effect. Mechanistically, BEX1 enhances Warburg effect through the downregulation of peroxisome proliferator-activated receptor-gamma (PPARγ). Furthermore, pyruvate dehydrogenase kinase isozyme 1 (PDK1) is required for PPARγ-induced inhibition of Warburg effect in HB. In addition, BEX1 supports the stemness of HB by enhancing Warburg effect in a PPARγ/PDK1 dependent manner.

CONCLUSIONS

HB patients with high BEX1 and PDK1 expression had a poor prognosis. BEX1 promotes the stemness maintenance of HB cells via modulating the Warburg effect, which depends on PPARγ/PDK1 axis. Pioglitazone could be used to target BEX1-mediated stemness properties in HB by upregulating PPARγ.

A novel SLC25A1 inhibitor, parthenolide, suppresses the growth and stemness of liver cancer stem cells with metabolic vulnerability

Liver cancer stem cells (LCSCs) are recognized as key contributors to hepatocarcinogenesis, progression, and recurrence. Consequently, eradicating LCSCs has a great chance of increasing long-term survival in patients with liver cancer. Parthenolide (PTL), a natural sesquiterpene lactone product, possesses robust antitumor activity. However, the effects of PTL on LCSCs and underlying mechanisms remain unknown. Here we show that administration of PTL stimulated cell cycle arrest at the G1 phase, induced apoptosis, and decreased the stemness of LCSCs. Further research indicates that PTL caused the production of ROS and the reduction of oxidative phosphorylation (OXPHOS) and mitochondrial membrane potential (MMP) levels of LCSCs. RNA sequencing (RNA-Seq) further shows that PTL decreased SLC25A1 expression at the mRNA level and that inhibition of SLC25A1 synergistically decreased the expression of IDH2 and several pivotal genes involved in mitochondrial respiratory chain complex, resulting in the production of ROS and mitochondrial dysfunction. In addition, the inhibitory effect of PTL on mitochondrial function and self-renewal capacity of LCSCs was abolished by the knockdown of SLC25A1 or treatment with SLC25A1 inhibitor CTPI-2. Importantly, PTL prevented liver cancer growth in vivo without clearly causing toxicity. Our research shows that PTL inhibits the growth and stemness of LCSCs through SLC25A1-mediated mitochondrial function. PTL may be a potential candidate natural agent for liver cancer treatment.

Rewiring of mitochondrial metabolism in therapy-resistant cancers: permanent and plastic adaptations

Deregulation of tumor cell metabolism is widely recognized as a "hallmark of cancer." Many of the selective pressures encountered by tumor cells, such as exposure to anticancer therapies, navigation of the metastatic cascade, and communication with the tumor microenvironment, can elicit further rewiring of tumor cell metabolism. Furthermore, phenotypic plasticity has been recently appreciated as an emerging "hallmark of cancer." Mitochondria are dynamic organelles and central hubs of metabolism whose roles in cancers have been a major focus of numerous studies. Importantly, therapeutic approaches targeting mitochondria are being developed. Interestingly, both plastic (i.e., reversible) and permanent (i.e., stable) metabolic adaptations have been observed following exposure to anticancer therapeutics. Understanding the plastic or permanent nature of these mechanisms is of crucial importance for devising the initiation, duration, and sequential nature of metabolism-targeting therapies. In this review, we compare permanent and plastic mitochondrial mechanisms driving therapy resistance. We also discuss experimental models of therapy-induced metabolic adaptation, therapeutic implications for targeting permanent and plastic metabolic states, and clinical implications of metabolic adaptations. While the plasticity of metabolic adaptations can make effective therapeutic treatment challenging, understanding the mechanisms behind these plastic phenotypes may lead to promising clinical interventions that will ultimately lead to better overall care for cancer patients.

Modelling cell adaptation using internal variables: Accounting for cell plasticity in continuum mathematical biology

Cellular adaptation is the ability of cells to change in response to different stimuli and environmental conditions. It occurs via phenotypic plasticity, that is, changes in gene expression derived from changes in the physiological environment. This phenomenon is important in many biological processes, in particular in cancer evolution and its treatment. Therefore, it is crucial to understand the mechanisms behind it. Specifically, the emergence of the cancer stem cell phenotype, showing enhanced proliferation and invasion rates, is an essential process in tumour progression. We present a mathematical framework to simulate phenotypic heterogeneity in different cell populations as a result of their interaction with chemical species in their microenvironment, through a continuum model using the well-known concept of internal variables to model cell phenotype. The resulting model, derived from conservation laws, incorporates the relationship between the phenotype and the history of the stimuli to which cells have been subjected, together with the inheritance of that phenotype. To illustrate the model capabilities, it is particularised for glioblastoma adaptation to hypoxia. A parametric analysis is carried out to investigate the impact of each model parameter regulating cellular adaptation, showing that it permits reproducing different trends reported in the scientific literature. The framework can be easily adapted to any particular problem of cell plasticity, with the main limitation of having enough cells to allow working with continuum variables. With appropriate calibration and validation, it could be useful for exploring the underlying processes of cellular adaptation, as well as for proposing favourable/unfavourable conditions or treatments.

Mitochondria in Cancer Stem Cells: From an Innocent Bystander to a Central Player in Therapy Resistance

Cancer continues to rank among the world's leading causes of mortality despite advancements in treatment. Cancer stem cells, which can self-renew, are present in low abundance and contribute significantly to tumor recurrence, tumorigenicity, and drug resistance to various therapies. The drug resistance observed in cancer stem cells is attributed to several factors, such as cellular quiescence, dormancy, elevated aldehyde dehydrogenase activity, apoptosis evasion mechanisms, high expression of drug efflux pumps, protective vascular niche, enhanced DNA damage response, scavenging of reactive oxygen species, hypoxic stability, and stemness-related signaling pathways. Multiple studies have shown that mitochondria play a pivotal role in conferring drug resistance to cancer stem cells, through mitochondrial biogenesis, metabolism, and dynamics. A better understanding of how mitochondria contribute to tumorigenesis, heterogeneity, and drug resistance could lead to the development of innovative cancer treatments.

Surmounting Cancer Drug Resistance: New Perspective on RNA-Binding Proteins

RNA-binding proteins (RBPs), being pivotal elements in both physiological and pathological processes, possess the ability to directly impact RNA, thereby exerting a profound influence on cellular life. Furthermore, the dysregulation of RBPs not only induces alterations in the expression levels of genes associated with cancer but also impairs the occurrence of post-transcriptional regulatory mechanisms. Consequently, these circumstances can give rise to aberrations in cellular processes, ultimately resulting in alterations within the proteome. An aberrant proteome can disrupt the equilibrium between oncogenes and tumor suppressor genes, promoting cancer progression. Given their significant role in modulating gene expression and post-transcriptional regulation, directing therapeutic interventions towards RBPs represents a viable strategy for combating drug resistance in cancer treatment. RBPs possess significant potential as diagnostic and prognostic markers for diverse cancer types. Gaining comprehensive insights into the structure and functionality of RBPs, along with delving deeper into the molecular mechanisms underlying RBPs in tumor drug resistance, can enhance cancer treatment strategies and augment the prognostic outcomes for individuals afflicted with cancer.

The Regulation of m6A Modification in Glioblastoma: Functional Mechanisms and Therapeutic Approaches

Glioblastoma is the most prevalent primary brain tumour and invariably confers a poor prognosis. The immense intra-tumoral heterogeneity of glioblastoma and its ability to rapidly develop treatment resistance are key barriers to successful therapy. As such, there is an urgent need for the greater understanding of the tumour biology in order to guide the development of novel therapeutics in this field. N6-methyladenosine (m6A) is the most abundant of the RNA modifications in eukaryotes. Studies have demonstrated that the regulation of this RNA modification is altered in glioblastoma and may serve to regulate diverse mechanisms including glioma stem-cell self-renewal, tumorigenesis, invasion and treatment evasion. However, the precise mechanisms by which m6A modifications exert their functional effects are poorly understood. This review summarises the evidence for the disordered regulation of m6A in glioblastoma and discusses the downstream functional effects of m6A modification on RNA fate. The wide-ranging biological consequences of m6A modification raises the hope that novel cancer therapies can be targeted against this mechanism.

The role of tumor microenvironment on cancer stem cell fate in solid tumors

In the last few decades, the role of cancer stem cells in initiating tumors, metastasis, invasion, and resistance to therapies has been recognized as a potential target for tumor therapy. Understanding the mechanisms by which CSCs contribute to cancer progression can help to provide novel therapeutic approaches against solid tumors. In this line, the effects of mechanical forces on CSCs such as epithelial-mesenchymal transition, cellular plasticity, etc., the metabolism pathways of CSCs, players of the tumor microenvironment, and their influence on the regulating of CSCs can lead to cancer progression. This review focused on some of these mechanisms of CSCs, paving the way for a better understanding of their regulatory mechanisms and developing platforms for targeted therapies. While progress has been made in research, more studies will be required in the future to explore more aspects of how CSCs contribute to cancer progression. Video Abstract.

RNA-binding proteins in vascular inflammation and atherosclerosis

Atherosclerotic cardiovascular disease (ASCVD) remains the major cause of premature death and disability worldwide, even when patients with an established manifestation of atherosclerotic heart disease are optimally treated according to the clinical guidelines. Apart from the epigenetic control of transcription of the genetic information to messenger RNAs (mRNAs), gene expression is tightly controlled at the post-transcriptional level before the initiation of translation. Although mRNAs are traditionally perceived as the messenger molecules that bring genetic information from the nuclear DNA to the cytoplasmic ribosomes for protein synthesis, emerging evidence suggests that processes controlling RNA metabolism, driven by RNA-binding proteins (RBPs), affect cellular function in health and disease. Over the recent years, vascular endothelial cell, smooth muscle cell and immune cell RBPs have emerged as key co- or post-transcriptional regulators of several genes related to vascular inflammation and atherosclerosis. In this review, we provide an overview of cell-specific function of RNA-binding proteins involved in all stages of ASCVD and how this knowledge may be used for the development of novel precision medicine therapeutics.

A combined computational and functional approach identifies IGF2BP2 as a driver of chemoresistance in a wide array of pre-clinical models of colorectal cancer

AIM

Chemoresistance is a major cause of treatment failure in colorectal cancer (CRC) therapy. In this study, the impact of the IGF2BP family of RNA-binding proteins on CRC chemoresistance was investigated using in silico, in vitro, and in vivo approaches.

METHODS

Gene expression data from a well-characterized cohort and publicly available cross-linking immunoprecipitation sequencing (CLIP-Seq) data were collected. Resistance to chemotherapeutics was assessed in patient-derived xenografts (PDXs) and patient-derived organoids (PDOs). Functional studies were performed in 2D and 3D cell culture models, including proliferation, spheroid growth, and mitochondrial respiration analyses.

RESULTS

We identified IGF2BP2 as the most abundant IGF2BP in primary and metastastatic CRC, correlating with tumor stage in patient samples and tumor growth in PDXs. IGF2BP2 expression in primary tumor tissue was significantly associated with resistance to selumetinib, gefitinib, and regorafenib in PDOs and to 5-fluorouracil and oxaliplatin in PDX in vivo. IGF2BP2 knockout (KO) HCT116 cells were more susceptible to regorafenib in 2D and to oxaliplatin, selumitinib, and nintedanib in 3D cell culture. Further, a bioinformatic analysis using CLIP data suggested stabilization of target transcripts in primary and metastatic tumors. Measurement of oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) revealed a decreased basal OCR and an increase in glycolytic ATP production rate in IGF2BP2 KO. In addition, real-time reverse transcriptase polymerase chain reaction (qPCR) analysis confirmed decreased expression of genes of the respiratory chain complex I, complex IV, and the outer mitochondrial membrane in IGF2BP2 KO cells.

CONCLUSIONS

IGF2BP2 correlates with CRC tumor growth in vivo and promotes chemoresistance by altering mitochondrial respiratory chain metabolism. As a druggable target, IGF2BP2 could be used in future CRC therapy to overcome CRC chemoresistance.

Glioblastoma Metabolism: Insights and Therapeutic Strategies

Tumor metabolism is emerging as a potential target for cancer therapies. This new approach holds particular promise for the treatment of glioblastoma, a highly lethal brain tumor that is resistant to conventional treatments, for which improving therapeutic strategies is a major challenge. The presence of glioma stem cells is a critical factor in therapy resistance, thus making it essential to eliminate these cells for the long-term survival of cancer patients. Recent advancements in our understanding of cancer metabolism have shown that glioblastoma metabolism is highly heterogeneous, and that cancer stem cells exhibit specific metabolic traits that support their unique functionality. The objective of this review is to examine the metabolic changes in glioblastoma and investigate the role of specific metabolic processes in tumorigenesis, as well as associated therapeutic approaches, with a particular focus on glioma stem cell populations.

Targeting autophagy and lipid metabolism in cancer stem cells

Cancer stem cells (CSCs) are a subset of cancer cells with self-renewal ability and tumor initiating properties. Unlike the other non-stem cancer cells, CSCs resist traditional therapy and remain a major cause of disease relapse. With the recent advances in metabolomics, various studies have demonstrated that CSCs have distinct metabolic properties. Metabolic reprogramming in CSCs contributes to self-renewal and maintenance of stemness. Accumulating evidence suggests that rewiring of energy metabolism is a key player that enables to meet energy demands, maintains stemness, and sustains cancer growth and invasion. CSCs use various mechanisms such as increased glycolysis, redox signaling and autophagy modulation to overcome nutritional deficiency and sustain cell survival. The alterations in lipid metabolism acquired by the CSCs support biomass production through increased dependence on fatty acid synthesis and β-oxidation and contribute to oncogenic signaling pathways. This review summarizes our current understanding of lipid metabolism in CSCs and how pharmacological regulation of autophagy and lipid metabolism influences CSC phenotype. Increased dependence on lipid metabolism appears as an attractive strategy to eliminate CSCs using therapeutic agents that specifically target CSCs based on their modulation of lipid metabolism.

Regulative Roles of Metabolic Plasticity Caused by Mitochondrial Oxidative Phosphorylation and Glycolysis on the Initiation and Progression of Tumorigenesis

One important feature of tumour development is the regulatory role of metabolic plasticity in maintaining the balance of mitochondrial oxidative phosphorylation and glycolysis in cancer cells. In recent years, the transition and/or function of metabolic phenotypes between mitochondrial oxidative phosphorylation and glycolysis in tumour cells have been extensively studied. In this review, we aimed to elucidate the characteristics of metabolic plasticity (emphasizing their effects, such as immune escape, angiogenesis migration, invasiveness, heterogeneity, adhesion, and phenotypic properties of cancers, among others) on tumour progression, including the initiation and progression phases. Thus, this article provides an overall understanding of the influence of abnormal metabolic remodeling on malignant proliferation and pathophysiological changes in carcinoma.

Cancer Stem Cells in Pancreatic Ductal Adenocarcinoma

The first discovery of cancer stem cells (CSCs) in leukaemia triggered active research on stemness in neoplastic tissues. CSCs represent a subpopulation of malignant cells, defined by unique properties: a dedifferentiated state, self-renewal, pluripotency, an inherent resistance to chemo- and radiotherapy, the presence of certain epigenetic alterations, as well as a higher tumorigenicity in comparison with the general population of cancer cells. A combination of these features highlights CSCs as a high-priority target during cancer treatment. The presence of CSCs has been confirmed in multiple malignancies, including pancreatic ductal adenocarcinoma, an entity that is well known for its dismal prognosis. As the aggressive course of pancreatic carcinoma is partly attributable to treatment resistance, CSCs could contribute to adverse outcomes. The aim of this review is to summarize the current information regarding the markers and molecular features of CSCs in pancreatic ductal adenocarcinoma and the therapeutic options to remove them.

RNA-binding proteins in cancer drug discovery

RNA-binding proteins (RBPs) are crucial players in tumorigenesis and, hence, promising targets in cancer drug discovery. However, they are largely regarded as 'undruggable', because of the often noncatalytic and complex interactions between protein and RNA, which limit the discovery of specific inhibitors. Nonetheless, over the past 10 years, drug discovery efforts have uncovered RBP inhibitors with clinical relevance, highlighting the disruption of RNA-protein networks as a promising avenue for cancer therapeutics. In this review, we discuss the role of structurally distinct RBPs in cancer, and the mechanisms of RBP-directed small-molecule inhibitors (SMOIs) focusing on drug-protein interactions, binding surfaces, potency, and translational potential. Additionally, we underline the limitations of RBP-targeting drug discovery assays and comment on future trends in the field.

Aldose reductase and cancer metabolism: The master regulator in the limelight

It is strongly established that metabolic reprogramming mediates the initiation, progression, and metastasis of a variety of cancers. However, there is no common biomarker identified to link the dysregulated metabolism and cancer progression. Recent studies strongly advise the involvement of aldose reductase (AR) in cancer metabolism. AR-mediated glucose metabolism creates a Warburg-like effect and an acidic tumour microenvironment in cancer cells. Moreover, AR overexpression is associated with the impairment of mitochondria and the accumulation of free fatty acids in cancer cells. Further, AR-mediated reduction of lipid aldehydes and chemotherapeutics are involved in the activation of factors promoting proliferation and chemo-resistance. In this review, we have delineated the possible mechanisms by which AR modulates cellular metabolism for cancer proliferation and survival. An in-depth understanding of cancer metabolism and the role of AR might lead to the use of AR inhibitors as metabolic modulating agents for the therapy of cancer.

Novel roles for HMGA2 isoforms in regulating oxidative stress and sensitizing to RSL3-Induced ferroptosis in prostate cancer cells

Oxidative stress is increased in several cancers including prostate cancer, and is currently being exploited in cancer therapy to induce ferroptosis, a novel nonapoptotic form of cell death. High mobility group A2 (HMGA2), a non-histone protein up-regulated in several cancers, can be truncated due to chromosomal rearrangement or alternative splicing of HMGA2 gene. The purpose of this study is to investigate the role of wild-type vs. truncated HMGA2 in prostate cancer (PCa). We analyzed the expression of wild-type vs. truncated HMGA2 and showed that prostate cancer patient tissue and some cell lines expressed increasing amounts of both wild-type and truncated HMGA2 with increasing tumor grade, compared to normal epithelial cells. RNA-Seq analysis of LNCaP prostate cancer cells stably overexpressing wild-type HMGA2 (HMGA2-WT), truncated HMGA2 (HMGA2-TR) or empty vector (Neo) control revealed that HMGA2-TR cells exhibited higher oxidative stress compared to HMGA2-WT or Neo control cells, which was also confirmed by analysis of basal reactive oxygen species (ROS) levels using 2', 7'-dichlorofluorescin diacetate (DCFDA) dye, the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) and NADP/NADPH using metabolomics. This was associated with increased sensitivity to RAS-selective lethal 3 (RSL3)-induced ferroptosis that could be antagonized by ferrostatin-1. Additionally, proteomic and immunoprecipitation analyses showed that cytoplasmic HMGA2 protein interacted with Ras GTPase-activating protein-binding protein 1 (G3BP1), a cytoplasmic stress granule protein that responds to oxidative stress, and that G3BP1 transient knockdown increased sensitivity to ferroptosis even further. Endogenous knockdown of HMGA2 or G3BP1 in PC3 cells reduced proliferation which was reversed by ferrostatin-1. In conclusion, we show a novel role for HMGA2 in oxidative stress, particularly the truncated HMGA2, which may be a therapeutic target for ferroptosis-mediated prostate cancer therapy.

Single-cell heterogeneity of EGFR and CDK4 co-amplification is linked to immune infiltration in glioblastoma

Glioblastoma (GBM) is the most aggressive brain tumor, with a median survival of ∼15 months. Targeted approaches have not been successful in this tumor type due to the large extent of intratumor heterogeneity. Mosaic amplification of oncogenes suggests that multiple genetically distinct clones are present in each tumor. To uncover the relationships between genetically diverse subpopulations of GBM cells and their native tumor microenvironment, we employ highly multiplexed spatial protein profiling coupled with single-cell spatial mapping of fluorescence in situ hybridization (FISH) for EGFR, CDK4, and PDGFRA. Single-cell FISH analysis of a total of 35,843 single nuclei reveals that tumors in which amplifications of EGFR and CDK4 more frequently co-occur in the same cell exhibit higher infiltration of CD163+ immunosuppressive macrophages. Our results suggest that high-throughput assessment of genomic alterations at the single-cell level could provide a measure for predicting the immune state of GBM.

Lipogenesis promotes mitochondrial fusion and maintains cancer stemness in human NSCLC

Cancer stem-like cells (CSCs) are critically involved in cancer metastasis and chemoresistance, acting as one major obstacle in clinical practice. While accumulating studies have implicated the metabolic reprogramming of CSCs, mitochondrial dynamics in such cells remain poorly understood. Here we pinpointed OPA1hi with mitochondrial fusion as a metabolic feature of human lung CSCs, licensing their stem-like properties. Specifically, human lung CSCs exerted enhanced lipogenesis, inducing OPA1 expression via transcription factor SAM Pointed Domain containing ETS transcription Factor (SPDEF). In consequence, OPA1hi promoted mitochondrial fusion and stemness of CSCs. Such lipogenesishi, SPDEFhi, and OPA1hi metabolic adaptions were verified with primary CSCs from lung cancer patients. Accordingly, blocking lipogenesis and mitochondrial fusion efficiently impeded CSC expansion and growth of organoids derived from patients with lung cancer. Together, lipogenesis regulates mitochondrial dynamics via OPA1 for controlling CSCs in human lung cancer.

Expanding the Chemical Space of Arsenicin A-C Related Polyarsenicals and Evaluation of Some Analogs as Inhibitors of Glioblastoma Stem Cell Growth

The marine polyarsenical metabolite arsenicin A is the landmark of a series of natural and synthetic molecules characterized by an adamantane-like tetraarsenic cage. Arsenicin A and related polyarsenicals have been evaluated for their antitumor effects in vitro and have been proven more potent than the FDA-approved arsenic trioxide. In this context, we have expanded the chemical space of polyarsenicals related to arsenicin A by synthesizing dialkyl and dimethyl thio-analogs, the latter characterized with the support of simulated NMR spectra. In addition, the new natural arsenicin D, the scarcity of which in the Echinochalina bargibanti extract had previously limited its full structural characterization, has been identified by synthesis. The dialkyl analogs, which present the adamantane-like arsenicin A cage substituted with either two methyl, ethyl, or propyl chains, were efficiently and selectively produced and evaluated for their activity on glioblastoma stem cells (GSCs), a promising therapeutic target in glioblastoma treatment. These compounds inhibited the growth of nine GSC lines more potently than arsenic trioxide, with GI₅₀ values in the submicromolar range, both under normoxic and hypoxic conditions, and presented high selectivity toward non-tumor cell lines. The diethyl and dipropyl analogs, which present favorable physical-chemical and ADME parameters, had the most promising results.

Mitochondrial elongation factor 4 modulates energy metabolism and promotes breast cancer metastasis by orchestration of mitochondrial translation

To cope with the requirements of energy and building blocks for rapid proliferation, cancer cells reprogram their metabolic pathways profoundly, especially in oxygen- and nutrients-deficient tumor microenvironments. However, functional mitochondria and mitochondria-dependent oxidative phosphorylation are still necessary for the tumorigenesis and metastasis of cancer cells. We show here that mitochondrial elongation factor 4 (mtEF4) is commonly upregulated in breast tumors compared to adjacent non-cancerous tissues, and is relevant to tumor progression and poor prognosis. Down regulation of mtEF4 in breast cancer cells impairs the assembly of mitochondrial respiration complexes, decreases mitochondrial respiration, reduces ATP production, attenuates the formation of lamellipodia, and suppresses cell motility in vitro and cancer metastasis in vivo. On the contrary, upregulation of mtEF4 elevates the mitochondrial oxidative phosphorylation, which contributes to the migratory capacities of breast cancer cells. mtEF4 also increases the potential of glycolysis, probably via an AMPK-related mechanism. In summary, we provide direct evidences that the aberrantly upregulated mtEF4 contributes to the metastasis of breast cancer by coordinating metabolic pathways.

Mitochondrial-targeted nanoparticles: Delivery and therapeutic agents in cancer

Mitochondria are the powerhouses of cells and modulate the essential metabolic functions required for cellular survival. Various mitochondrial pathways, such as oxidative phosphorylation or production of reactive oxygen species (ROS) are dysregulated during cancer growth and development, rendering them attractive targets against cancer. Thus, the delivery of antitumor agents to mitochondria has emerged as a potential approach for treating cancer. Recent advances in nanotechnology have provided innovative solutions for overcoming the physical barriers posed by the structure of mitochondrial organelles, and have enabled the development of efficient mitochondrial nanoplatforms. In this review, we examine the importance of mitochondria during neoplastic development, explore the most recent smart designs of nano-based systems aimed at targeting mitochondria, and highlight key mitochondrial pathways in cancer cells.

Metabolic determinants of tumour initiation

Tumours exhibit notable metabolic alterations compared with their corresponding normal tissue counterparts. These metabolic alterations can support anabolic growth, enable survival in hostile environments and regulate gene expression programmes that promote malignant progression. Whether these metabolic changes are selected for during malignant transformation or can themselves be drivers of tumour initiation is unclear. However, intriguingly, many of the major bottlenecks for tumour initiation - control of cell fate, survival and proliferation - are all amenable to metabolic regulation. In this article, we review evidence demonstrating a critical role for metabolic pathways in processes that support the earliest stages of tumour development. We discuss how cell-intrinsic factors, such as the cell of origin or transforming oncogene, and cell-extrinsic factors, such as local nutrient availability, promote or restrain tumour initiation. Deeper insight into how metabolic pathways control tumour initiation will improve our ability to design metabolic interventions to limit tumour incidence.

The Emerging Role of m6A Modification in Endocrine Cancer

With the development of RNA modification research, N6-methyladenosine (m6A) is regarded as one of the most important internal epigenetic modifications of eukaryotic mRNA. It is also regulated by methylase, demethylase, and protein preferentially recognizing the m6A modification. This dynamic and reversible post-transcriptional RNA alteration has steadily become the focus of cancer research. It can increase tumor stem cell self-renewal and cell proliferation. The m6A-modified genes may be the primary focus for cancer breakthroughs. Although some endocrine cancers are rare, they may have a high mortality rate. As a result, it is critical to recognize the significance of endocrine cancers and identify new therapeutic targets that will aid in improving disease treatment and prognosis. We summarized the latest experimental progress in the m6A modification in endocrine cancers and proposed the m6A alteration as a potential diagnostic marker for endocrine malignancies.

Streptogramin A derivatives as mitochondrial translation inhibitors to suppress glioblastoma stem cell growth

New therapeutic strategies for glioblastoma treatment, especially tackling the tumour's glioblastoma stem cell (GSC) component, are an urgent medical need. Recently, mitochondrial translation inhibition has been shown to affect GSC growth, clonogenicity, and self-renewal capability, therefore becoming an attractive therapeutic target. The combination of streptogramins B and A antibiotics quinupristin/dalfopristin (Q/D), which inhibits mitochondrial ribosome function, affects GSCs more effectively in vitro than the standard of care temozolomide. Here, docking calculations based on the cryo-EM structure of the Q/D-bound mitochondrial ribosome have been used to develop a series of streptogramin A derivatives. We obtained twenty-two new and known molecules starting from the dalfopristin and virginiamycin M1 scaffolds. A structure-activity relationship refinement was performed to evaluate the capability of these compounds to suppress GSC growth and inhibit mitochondrial translation, either alone or in combination with quinupristin. Finally, quantitative ultra HPLC-mass spectrometry allowed us to assess the cell penetration of some of these derivatives. Among all, the fluorine derivatives of dalfopristin and virginiamycin M1, (16R)-1e and (16R)-2e, respectively, and flopristin resulted in being more potent than the corresponding lead compounds and penetrating to a greater extent into the cells. We, therefore, propose these three compounds for further evaluation in vivo as antineoplastic agents.

Isoproterenol Alters Metabolism, Promotes Survival and Migration in 5-Fluorouracil-Treated SW480 Cells with and without Beta-hydroxybutyrate

People with cancer often experience long-term physical and psychological stress, which can have a significant impact on tumor metabolism and treatment. The effects of adrenergic signaling on metabolic pathways are well known, but only a few studies have looked into the connection between this signaling and tumor metabolism. This study examined the effects of treatment with isoproterenol (Iso) alone and in combination with β-hydroxybutyrate (βHB), a mitochondrial fuel, on the metabolism, survival, and migration of SW480 colon cancer cells treated with 5-fluorouracil (5FU). The researchers measured the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) to determine the metabolic profile of these cells. They also analyzed the gene expression of PGC-1α, c-MYC, and NANOG to investigate the relationship between metabolic phenotype and stemness status. Scratch assays were used to assess cell migration. The results showed that Iso treatment increased cell viability in both SW480 and 5FU-treated SW480 cells. There was a significant decrease in ECAR and an increase in OCR after Iso treatment in both cell types. The expression of c-MYC and NANOG, genes associated with stemness, increased, while the expression of PGC-1α, a gene related to oxidative phosphorylation, decreased following Iso treatment. Iso treatment also increased the migration potential of both SW480 and 5FU-treated SW480 cells. These findings suggest that under stressful conditions, 5FU-treated colon cancer cells can utilize the oxidative phosphorylation pathway for growth and migration.

Structure, Function, and Inhibitors of the Mitochondrial Chaperone TRAP1

Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a mitochondrial molecular chaperone modulating cellular metabolism and signaling pathways by altering the conformation, activity, and stability of numerous substrate proteins called clients. It exerts its chaperone function as an adaptive response to counter cellular stresses instead of maintaining housekeeping protein homeostasis. However, the stress-adaptive machinery becomes dysregulated to support the progression and maintenance of human diseases, such as cancers; therefore, TRAP1 has been proposed as a promising target protein for anticancer drug development. In this review, by collating recent reports on high-resolution TRAP1 structures and structure-activity relationships of inhibitors, we aimed to provide better insights into the chaperoning mechanism of the emerging drug target and to suggest an efficient strategy for the development of potent TRAP1 inhibitors.