Cancer-Associated IDH1 Promotes Growth and Resistance to Targeted Therapies in the Absence of Mutation

Phosphorylation of IDH1 Facilitates Progestin Resistance in Endometrial Cancer

The progestin regimen is one of the main therapeutic strategies for women with endometrial cancer who undergo conservative management. Although many patients respond well to initial therapy, progestin-refractory disease inevitably emerges, and the molecular basis underlying progestin resistance has not been comprehensively elucidated. Herein, they demonstrated progestin results in p38-dependent IDH1 Thr 77 phosphorylation (pT77-IDH1). pT77-IDH1 translocates into the nucleus and is recruited to chromatin through its interaction with OCT6. IDH1-produced α-ketoglutarate (αKG) then facilitates the activity of OCT6 to promote focal adhesion related target gene transcription to confer progestin resistance. Pharmacological inhibition of p38 or focal adhesion signaling sensitizes endometrial cancer cells to progestin in vivo. The study reveals p38-dependent pT77-IDH1 as a key mediator of progestin resistance and a promising target for improving the efficacy of progestin therapy.

Enhancement of de novo lipogenesis by the IDH1 and IDH2-dependent reverse TCA cycle maintains the growth and angiogenic capacity of bone marrow-derived endothelial progenitor cells under hypoxia

BACKGROUND

Bone marrow-derived endothelial progenitor cells (EPCs) play a dynamic role in maintaining the structure and function of blood vessels. But how these cells maintain their growth and angiogenic capacity under bone marrow hypoxic niche is still unclear. This study aims to explore the mechanisms from a perspective of cellular metabolism.

METHODS

XFe96 Extracellular Flux Analyzer was used to analyze the metabolic status of EPCs. Gas Chromatography-Mass Spectrometry (GC-MS) was used to trace the carbon movement of 13C-labeled glucose and glutamine under 1 % O2 (hypoxia) and ∼20 % O2 (normoxia). Moreover, RNA interference, targeting isocitrate dehydrogenase-1 (IDH1) and IDH2, was used to inhibit the reverse tricarboxylic acid (TCA) cycle and analyze metabolic changes via isotope tracing as well as changes in cell growth and angiogenic potential under hypoxia. The therapeutic potential of EPCs under hypoxia was investigated in the ischemic hindlimb model.

RESULTS

Compared with normoxic cells, hypoxic cells showed increased glycolysis and decreased mitochondrial respiration. Isotope metabolic tracing revealed that under hypoxia, the forward TCA cycle was decreased and the reverse TCA cycle was enhanced, mediating the conversion of α-ketoglutarate (α-KG) into isocitrate/citrate, and de novo lipid synthesis was promoted. Downregulation of IDH1 or IDH2 under hypoxia suppressed the reverse TCA cycle, attenuated de novo lipid synthesis (DNL), elevated α-KG levels, and decreased the expression of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor A (VEGFA), eventually inhibiting the growth and angiogenic capacity of EPCs. Importantly, the transplantation of hypoxia-cultured EPCs in a mouse model of limb ischemia promoted new blood vessel regeneration and blood supply recovery in the ischemic area better than the transplantation of normoxia-cultured EPCs.

CONCLUSIONS

Under hypoxia, the IDH1- and IDH2-mediated reverse TCA cycle promotes glutamine-derived de novo lipogenesis and stabilizes the expression of α-KG and HIF-1α, thereby enhancing the growth and angiogenic capacity of EPCs.

Enhancing Endosomal Escape and Gene Regulation Activity for Spherical Nucleic Acids

The therapeutic potential of small interfering RNAs (siRNAs) is limited by their poor stability and low cellular uptake. When formulated as spherical nucleic acids (SNAs), siRNAs are resistant to nuclease degradation and enter cells without transfection agents with enhanced activity compared to their linear counterparts; however, the gene silencing activity of SNAs is limited by endosomal entrapment, a problem that impacts many siRNA-based nanoparticle constructs. To increase cytosolic delivery, SNAs are formulated using calcium chloride (CaCl2 ) instead of the conventionally used sodium chloride (NaCl). The divalent calcium (Ca2+ ) ions remain associated with the multivalent SNA and have a higher affinity for SNAs compared to their linear counterparts. Importantly, confocal microscopy studies show a 22% decrease in the accumulation of CaCl2 -salted SNAs within the late endosomes compared to NaCl-salted SNAs, indicating increased cytosolic delivery. Consistent with this finding, CaCl2 -salted SNAs comprised of siRNA and antisense DNA all exhibit enhanced gene silencing activity (up to 20-fold), compared to NaCl-salted SNAs regardless of sequence or cell line (U87-MG and SK-OV-3) studied. Moreover, CaCl2 -salted SNA-based forced intercalation probes show improved cytosolic mRNA detection.

HSP90a promotes the resistance to oxaliplatin in HCC through regulating IDH1-induced cell competition

Though burgeoning research manifests that cell competition, an essential selection and quality control mechanism for maintaining tissue or organ growth and homeostasis in multicellular organisms, is closely related to tumorigenesis and development, the mechanism of cell competition associated with tumor drug resistance remains elusive. In the study, we uncovered that oxaliplatin-resistant hepatocellular carcinoma (HCC) cells exhibit a pronounced competitive advantage against their sensitive counterparts, which is related to lipid takeover of resistant cells from sensitive cells. Of note, such lipid takeover is dependent on the existence of isocitrate dehydrogenase 1 (IDH1) in resistant HCC cells. Mechanistically, IDH1 activity is regulated by heat shock protein 90 alpha (HSP90α) through binding with each other, which orchestrates the expressions of lipid metabolic enzymes and lipid accumulation in resistant HCC cells. Our results suggest that HCC cell competition-driven chemoresistance can be regulated by HSP90α/IDH1-mediated lipid metabolism, which may serve as a promising target for overcoming drug resistance in HCC.

αKG-mediated carnitine synthesis promotes homologous recombination via histone acetylation

Homologous recombination (HR) deficiency enhances sensitivity to DNA damaging agents commonly used to treat cancer. In HR-proficient cancers, metabolic mechanisms driving response or resistance to DNA damaging agents remain unclear. Here we identified that depletion of alpha-ketoglutarate (αKG) sensitizes HR-proficient cells to DNA damaging agents by metabolic regulation of histone acetylation. αKG is required for the activity of αKG-dependent dioxygenases (αKGDDs), and prior work has shown that changes in αKGDD affect demethylases. Using a targeted CRISPR knockout library consisting of 64 αKGDDs, we discovered that Trimethyllysine Hydroxylase Epsilon (TMLHE), the first and rate-limiting enzyme in de novo carnitine synthesis, is necessary for proliferation of HR-proficient cells in the presence of DNA damaging agents. Unexpectedly, αKG-mediated TMLHE-dependent carnitine synthesis was required for histone acetylation, while histone methylation was affected but dispensable. The increase in histone acetylation via αKG-dependent carnitine synthesis promoted HR-mediated DNA repair through site- and substrate-specific histone acetylation. These data demonstrate for the first time that HR-proficiency is mediated through αKG directly influencing histone acetylation via carnitine synthesis and provide a metabolic avenue to induce HR-deficiency and sensitivity to DNA damaging agents.

Local administration of irinotecan using an implantable drug delivery device stops high-grade glioma tumor recurrence in a glioblastoma tumor model

The treatment for Glioblastoma is limited due to the presence of the blood brain barrier, which restricts the entry of chemotherapeutic drugs into the brain. Local delivery into the tumor resection margin has the potential to improve efficacy of chemotherapy. We developed a safe and clinically translatable irinotecan implant for local delivery to increase its efficacy while minimizing systemic side effects. Irinotecan-loaded implants were manufactured using hot melt extrusion, gamma sterilized at 25 kGy, and characterized for their irinotecan content, release, and drug diffusion. Their therapeutic efficacy was evaluated in a patient-derived xenograft mouse resection model of glioblastoma. Their safety and translatability were evaluated using histological analysis of brain tissue and serum chemistry analysis. Implants containing 30% and 40% w/w irinotecan were manufactured without plasticizer. The 30% and 40% implants showed moderate local toxicity up to 2- and 6-day post-implantation. Histopathology of the implantation site showed signs of necrosis at days 45 and 14 for the 30% and 40% implants. Hematological analysis and clinical chemistry showed no signs of serious systemic toxicity for either implant. The 30% implants had an 80% survival at day 148, with no sign of tumor recurrence. Gamma sterilization and 12-month storage had no impact on the integrity of the 30% implants. This study demonstrates that the 30% implants are a promising novel treatment for glioblastoma that could be quickly translated into the clinic.

Metabolism and signaling crosstalk in glioblastoma progression and therapy resistance

Glioblastoma is the most common form of primary malignant brain tumor in adults and one of the most lethal human cancers, with high recurrence and therapy resistance. Glioblastoma cells display extensive genetic and cellular heterogeneity, which precludes a unique and common therapeutic approach. The standard of care in glioblastoma patients includes surgery followed by radiotherapy plus concomitant temozolomide. As in many other cancers, cell signaling is deeply affected due to mutations or alterations in the so-called molecular drivers. Moreover, glioblastoma cells undergo metabolic adaptations to meet the new demands in terms of energy and building blocks, with an increasing amount of evidence connecting metabolic transformation and cell signaling deregulation in this type of aggressive brain tumor. In this review, we summarize some of the most common alterations both in cell signaling and metabolism in glioblastoma, presenting an integrative discussion about how they contribute to therapy resistance. Furthermore, this review aims at providing a comprehensive overview of the state-of-the-art of therapeutic approaches and clinical trials exploiting signaling and metabolism in glioblastoma.

Wild-type IDH1 maintains NSCLC stemness and chemoresistance through activation of the serine biosynthetic pathway

Tumor-initiating cells (TICs) reprogram their metabolic features to meet their bioenergetic, biosynthetic, and redox demands. Our previous study established a role for wild-type isocitrate dehydrogenase 1 (IDH1WT) as a potential diagnostic and prognostic biomarker for non-small cell lung cancer (NSCLC), but how IDH1WT modulates NSCLC progression remains elusive. Here, we report that IDH1WT activates serine biosynthesis by enhancing the expression of phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase 1 (PSAT1), the first and second enzymes of de novo serine synthetic pathway. Augmented serine synthesis leads to GSH/ROS imbalance and supports pyrimidine biosynthesis, maintaining tumor initiation capacity and enhancing gemcitabine chemoresistance. Mechanistically, we identify that IDH1WT interacts with and stabilizes PHGDH and fragile X-related protein-1 (FXR1) by impeding their association with the E3 ubiquitin ligase parkin by coimmunoprecipitation assay and proximity ligation assay. Subsequently, stabilized FXR1 supports PSAT1 mRNA stability and translation, as determined by actinomycin D chase experiment and in vitro translation assay. Disrupting IDH1WT-PHGDH and IDH1WT-FXR1 interactions synergistically reduces NSCLC stemness and sensitizes NSCLC cells to gemcitabine and serine/glycine-depleted diet therapy in lung cancer xenograft models. Collectively, our findings offer insights into the role of IDH1WT in serine metabolism, highlighting IDH1WT as a potential therapeutic target for eradicating TICs and overcoming gemcitabine chemoresistance in NSCLC.

Targeting intracellular oncoproteins with dimeric IgA promotes expulsion from the cytoplasm and immune-mediated control of epithelial cancers

Dimeric IgA (dIgA) can move through cells via the IgA/IgM polymeric immunoglobulin receptor (PIGR), which is expressed mainly on mucosal epithelia. Here, we studied the ability of dIgA to target commonly mutated cytoplasmic oncodrivers. Mutation-specific dIgA, but not IgG, neutralized KRASG12D within ovarian carcinoma cells and expelled this oncodriver from tumor cells. dIgA binding changed endosomal trafficking of KRASG12D from accumulation in recycling endosomes to aggregation in the early/late endosomes through which dIgA transcytoses. dIgA targeting of KRASG12D abrogated tumor cell proliferation in cell culture assays. In vivo, KRASG12D-specific dIgA1 limited the growth of KRASG12D-mutated ovarian and lung carcinomas in a manner dependent on CD8+ T cells. dIgA specific for IDH1R132H reduced colon cancer growth, demonstrating effective targeting of a cytoplasmic oncodriver not associated with surface receptors. dIgA targeting of KRASG12D restricted tumor growth more effectively than small-molecule KRASG12D inhibitors, supporting the potential of this approach for the treatment of human cancers.

Redox Homeostasis and Beyond: The Role of Wild-Type Isocitrate Dehydrogenases for the Pathogenesis of Glioblastoma

Significance: Glioblastoma is an aggressive and devastating brain tumor characterized by a dismal prognosis and resistance to therapeutic intervention. To support catabolic processes critical for unabated cellular growth and defend against harmful reactive oxygen species, glioblastoma tumors upregulate the expression of wild-type isocitrate dehydrogenases (IDHs). IDH enzymes catalyze the oxidative decarboxylation of isocitrate to α-ketoglutarate (α-KG), NAD(P)H, and CO2. On molecular levels, IDHs epigenetically control gene expression through effects on α-KG-dependent dioxygenases, maintain redox balance, and promote anaplerosis by providing cells with NADPH and precursor substrates for macromolecular synthesis. Recent Advances: While gain-of-function mutations in IDH1 and IDH2 represent one of the most comprehensively studied mechanisms of IDH pathogenic effects, recent studies identified wild-type IDHs as critical regulators of normal organ physiology and, when transcriptionally induced or down regulated, as contributing to glioblastoma progression. Critical Issues: Here, we will discuss molecular mechanisms of how wild-type IDHs control glioma pathogenesis, including the regulation of oxidative stress and de novo lipid biosynthesis, and provide an overview of current and future research directives that aim to fully characterize wild-type IDH-driven metabolic reprogramming and its contribution to the pathogenesis of glioblastoma. Future Directions: Future studies are required to further dissect mechanisms of metabolic and epigenomic reprogramming in tumors and the tumor microenvironment, and to develop pharmacological approaches to inhibit wild-type IDH function. Antioxid. Redox Signal. 39, 923-941.

Regulation and signaling pathways in cancer stem cells: implications for targeted therapy for cancer

Cancer stem cells (CSCs), initially identified in leukemia in 1994, constitute a distinct subset of tumor cells characterized by surface markers such as CD133, CD44, and ALDH. Their behavior is regulated through a complex interplay of networks, including transcriptional, post-transcriptional, epigenetic, tumor microenvironment (TME), and epithelial-mesenchymal transition (EMT) factors. Numerous signaling pathways were found to be involved in the regulatory network of CSCs. The maintenance of CSC characteristics plays a pivotal role in driving CSC-associated tumor metastasis and conferring resistance to therapy. Consequently, CSCs have emerged as promising targets in cancer treatment. To date, researchers have developed several anticancer agents tailored to specifically target CSCs, with some of these treatment strategies currently undergoing preclinical or clinical trials. In this review, we outline the origin and biological characteristics of CSCs, explore the regulatory networks governing CSCs, discuss the signaling pathways implicated in these networks, and investigate the influential factors contributing to therapy resistance in CSCs. Finally, we offer insights into preclinical and clinical agents designed to eliminate CSCs.

Lycorine promotes IDH1 acetylation to induce mitochondrial dynamics imbalance in colorectal cancer cells

Isocitrate dehydrogenase (IDH) 1 and 2, as essential enzymes in energy metabolism, contribute to the survival and drug resistance of a variety of solid tumors, especially for colorectal cancer (CRC). However, the underlying molecular mechanism still remains unclear. In this study, IDH1 was identified as a crucial cellular target of a natural-derived anti-CRC small molecule lycorine, using the unbiased thermal proteome profiling (TPP) strategy. We found that lycorine directly targeted a unique C-terminal domain of IDH1, and disrupted IDH1 interaction with deacetylase sirtuin 1 (SIRT1), thereby significantly promoting IDH1 acetylation modification. Then, lycorine noticeably triggered oxidative stress in CRC cells to cause mitochondrial membranes injury, and subsequently facilitated mitochondrial fission. Specific knockdown of IDH1 or SIRT1 markedly aggrieved lycorine-mediated oxidative stress and mitochondrial fragmentation in CRC cells. Furthermore, the combination of lycorine and sirtuins blocker nicotinamide (NAM) exhibited a synergic therapeutic effect in CRC cells. Collectively, our results reveal that IDH1 may serve as a promising therapeutic target for CRC via pharmacologically driving oxidative stress-dependent mitochondrial dynamics imbalance.

What Role Does Radiotherapy Play in the Molecular Era for Intrahepatic Cholangiocarcinoma?

ABSTRACT

Intrahepatic cholangiocarcinoma is a rare disease, yet with rising incidence globally. Most patients are not eligible for potentially curative surgical resection, and many patients with unresectable disease die within 12 months of diagnosis, primarily due to liver failure from the primary tumor. Recent prospective and retrospective studies indicate that local control of the primary tumor can be achieved with hypofractionated radiotherapy in patients with unresectable disease, translating into prolonged survival of these patients. During the time that these encouraging reports for radiotherapy have been published, numerous concurrent studies have also shown that intrahepatic cholangiocarcinoma is a molecularly diverse disease with multiple targetable genetic alterations and a complex tumor microenvironment. These biological insights have translated into new drug approvals for subsets of patients. We review the current knowledge about the biology and targeted treatment of intrahepatic cholangiocarcinoma and describe these developments in the context of modern radiotherapy.

Nuclear transport surveillance of p53 by nuclear pores in glioblastoma

Nuclear pore complexes (NPCs) are the central apparatus of nucleocytoplasmic transport. Disease-specific alterations of NPCs contribute to the pathogenesis of many cancers; however, the roles of NPCs in glioblastoma (GBM) are unknown. In this study, we report genomic amplification of NUP107, a component of NPCs, in GBM and show that NUP107 is overexpressed simultaneously with MDM2, a critical E3 ligase that mediates p53 degradation. Depletion of NUP107 inhibits the growth of GBM cell lines through p53 protein stabilization. Mechanistically, NPCs establish a p53 degradation platform via an export pathway coupled with 26S proteasome tethering. NUP107 is the keystone for NPC assembly; the loss of NUP107 affects the integrity of the NPC structure, and thus the proportion of 26S proteasome in the vicinity of nuclear pores significantly decreases. Together, our findings establish roles of NPCs in transport surveillance and provide insights into p53 inactivation in GBM.

RARRES2 is Downregulated in Isocitrate Dehydrogenase 1 Mutant Glioma Patients and Served as an Unfavorable Prognostic Factor of Glioma

BACKGROUND

Mutations in isocitrate dehydrogenase 1 (IDH1) induce extensive transcriptional alterations to promote glioma development. However, IDH1 mutation contributes the better clinical outcomes of glioma. Further understanding the transcriptional and DNA methylation changes mediated by IDH1 mutation will provide new therapeutic targets for glioma.

METHODS

Public glioma cohorts were collected and processed using R software. The transcriptional changes mediated by IDH1 mutation were determined and presented using heatmap. The differentially expressed genes in IDH1 mutant glioma were overlapped using TBtools. The prognostic effects of IDH1 regulated genes were determined by Kaplan-Meier survival analysis.

RESULTS

Retinoic acid receptor responder 2 (RARRES2) was upregulated in IDH1 wild type lower-grade glioma (LGG) patients, and higher expression levels of RARRES2 were associated with worse clinical outcomes of LGG. Moreover, IDH1 wild type LGG patients with higher expression levels of RARRES2 had even worse overall survival. Compared with LGG, RARRES2 was upregulated in grade IV glioma (glioblastoma multiforme, GBM). Also, RARRES2 represented an unfavorable prognostic factor of glioma. In GBM, RARRES2 was also associated with IDH1 mutation. In both LGG and GBM, IDH1 mutation induced extensive DNA hypermethylation, and more than half genes that were downregulated in IDH1 mutant glioma were contributed by DNA hypermethylation. RARRES2 was also hypermethylated in IDH1 mutant LGG or GBM patients. Furthermore, RARRES2 hypomethylation was an unfavorable prognostic factor in patients with LGG.

CONCLUSIONS

RARRES2 was downregulated by IDH1 mutation and served as an unfavorable prognostic factor in glioma.

High Expression of CDCA7 in the Prognosis of Glioma and Its Relationship with Ferroptosis and Immunity

CDCA7 is a copy number amplification gene that promotes tumorigenesis. However, the clinical relevance and potential mechanisms of CDCA7 in glioma are unclear. CDCA7 expression level data were obtained from the Chinese Glioma Genome Atlas (CGGA) and The Cancer Genome Atlas (TCGA) databases, and the enriched genes and related signaling pathways were explored. Data on genes in CDCA7-related signaling pathways and nine marker genes of ferroptosis were retrieved and a protein-protein interaction (PPI) network analysis was performed. The correlation of CDCA7 to ferroptosis and tumor infiltration of 22 kinds of human immune cells and the association between CDCA7 and immune checkpoint molecules were analyzed. CDCA7 was significantly increased in gliomas in comparison to healthy tissues. Gene Ontology (GO) and gene set enrichment analysis (GSEA) revealed the impact of CDCA7 expression on multiple biological processes and signaling pathways. CDCA7 may affect ferroptosis by interacting with genes in the cell cycle pathway and P53 pathway. The increase in CDCA7 was positively correlated with multiple ferroptosis suppressor genes and genes involved in tumor-infiltrating immune cells and immune checkpoint molecules in glioma. CDCA7 can be a new prognostic factor for glioma, which is closely related to ferroptosis, tumor immune cell infiltration, and immune checkpoint.

PRMT1 driven PTX3 regulates ferritinophagy in glioma

Mutations in the Krebs cycle enzyme IDH1 (isocitrate dehydrogenase (NADP(+)) 1) are associated with better prognosis in gliomas. Though IDH1 mutant (IDH1R132H) tumors are characterized by their antiproliferative signatures maintained through hypermethylation of DNA and chromatin, mechanisms affecting cell death pathways in these tumors are not well elucidated. On investigating the crosstalk between the IDH1 mutant epigenome, ferritinophagy and inflammation, diminished expression of PRMT1 (protein arginine methyltransferase 1) and its associated asymmetric dimethyl epigenetic mark H4R3me2a was observed in IDH1R132H gliomas. Reduced expression of PRMT1 was concurrent with diminished levels of PTX3, a key secretory factor involved in cancer-related inflammation. Lack of PRMT1 H4R3me2a in IDH1 mutant glioma failed to epigenetically activate the expression of PTX3 with a reduction in YY1 (YY1 transcription factor) binding on its promoter. Transcriptional activation and subsequent secretion of PTX3 from cells was required for maintaining macroautophagic/autophagic balance as pharmacological or genetic ablation of PTX3 secretion in wild-type IDH1 significantly increased autophagic flux. Additionally, PTX3-deficient IDH1 mutant gliomas exhibited heightened autophagic signatures. Furthermore, we demonstrate that the PRMT1-PTX3 axis is important in regulating the levels of ferritin genes/iron storage and inhibition of this axis triggered ferritinophagic flux. This study highlights the conserved role of IDH1 mutants in augmenting ferritinophagic flux in gliomas irrespective of genetic landscape through inhibition of the PRMT1-PTX3 axis. This is the first study describing ferritinophagy in IDH1 mutant gliomas with mechanistic details. Of clinical importance, our study suggests that the PRMT1-PTX3 ferritinophagy regulatory circuit could be exploited for therapeutic gains.Abbreviations: 2-HG: D-2-hydroxyglutarate; BafA1: bafilomycin A1; ChIP: chromatin immunoprecipitation; FTH1: ferritin heavy chain 1; FTL: ferritin light chain; GBM: glioblastoma; HMOX1/HO-1: heme oxygenase 1; IHC: immunohistochemistry; IDH1: isocitrate dehydrogenase(NADP(+))1; MDC: monodansylcadaverine; NCOA4: nuclear receptor coactivator 4; NFE2L2/Nrf2: NFE2 like bZIP transcription factor 2; PTX3/TSG-14: pentraxin 3; PRMT: protein arginine methyltransferase; SLC40A1: solute carrier family 40 member 1; Tan IIA: tanshinone IIA; TCA: trichloroacetic acid; TEM: transmission electron microscopy; TNF: tumor necrosis factor.

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.

Evolving Diagnostic and Treatment Strategies for Pediatric CNS Tumors: The Impact of Lipid Metabolism

Pediatric neurological tumors are a heterogeneous group of cancers, many of which carry a poor prognosis and lack a "standard of care" therapy. While they have similar anatomic locations, pediatric neurological tumors harbor specific molecular signatures that distinguish them from adult brain and other neurological cancers. Recent advances through the application of genetics and imaging tools have reshaped the molecular classification and treatment of pediatric neurological tumors, specifically considering the molecular alterations involved. A multidisciplinary effort is ongoing to develop new therapeutic strategies for these tumors, employing innovative and established approaches. Strikingly, there is increasing evidence that lipid metabolism is altered during the development of these types of tumors. Thus, in addition to targeted therapies focusing on classical oncogenes, new treatments are being developed based on a broad spectrum of strategies, ranging from vaccines to viral vectors, and melitherapy. This work reviews the current therapeutic landscape for pediatric brain tumors, considering new emerging treatments and ongoing clinical trials. In addition, the role of lipid metabolism in these neoplasms and its relevance for the development of novel therapies are discussed.

p53-independent tumor suppression by cell-cycle arrest via CREB/ATF transcription factor OASIS

CREB/ATF transcription factor OASIS/CREB3L1 is upregulated in long-term-cultured astrocytes undergoing cell-cycle arrest due to loss of DNA integrity by repeated replication. However, the roles of OASIS in the cell cycle remain unexplored. We find that OASIS arrests the cell cycle at G₂/M phase after DNA damage via direct induction of p21. Cell-cycle arrest by OASIS is dominant in astrocytes and osteoblasts, but not in fibroblasts, which are dependent on p53. In a brain injury model, Oasis^-/- reactive astrocytes surrounding the lesion core show sustained growth and inhibition of cell-cycle arrest, resulting in prolonged gliosis. We find that some glioma patients exhibit low expression of OASIS due to high methylation of its promoter. Specific removal of this hypermethylation in glioblastomas transplanted into nude mice by epigenomic engineering suppresses the tumorigenesis. These findings suggest OASIS as a critical cell-cycle inhibitor with potential to act as a tumor suppressor.

Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer

Pancreatic cancer (PC) is one of the most aggressive types of cancer, with a five-year overall survival rate of 11% among all-comers. Current systemic therapeutic options are limited to cytotoxic chemotherapies which have limited clinical efficacy and are often associated with development of drug resistance. Analysis of The Cancer Genome Atlas showed that wild-type isocitrate dehydrogenase (wtIDH1) is overexpressed in pancreatic tumors. In this study, we focus on the potential roles of wtIDH1 in pancreatic cancer chemoresistance. We found that treatment of pancreatic cancer cells with chemotherapy induced expression of wtIDH1, and this serves as a key resistance factor. The enzyme is protective to cancer cells under chemotherapy-induced oxidative stress by producing NADPH and alpha-ketoglutarate to maintain redox balance and mitochondrial function. An FDA-approved mutant IDH1 inhibitor, ivosidenib (AG-120), is actually a potent wtDH1 inhibitor under a nutrient-deprived microenvironment, reflective of the pancreatic cancer microenvironment. Suppression of wtIDH1 impairs redox balance, results in increased ROS levels, and enhances chemotherapy induced apoptosis in pancreatic cancer vis ROS damage in vitro. In vivo experiments further revealed that inhibiting wtIDH1 enhances chemotherapy anti-tumor effects in patient-derived xenografts and murine models of pancreatic cancer. Pharmacologic wtIDH1 inhibition with ivosidenib represents an attractive option for combination therapies with cytotoxic chemotherapy for patients with pancreatic cancer. Based on these data, we have initiated phase Ib trial combining ivosidenib and multi-agent chemotherapy in patients with pancreatic cancer (NCT05209074).

Mutated Isocitrate Dehydrogenase (mIDH) as Target for PET Imaging in Gliomas

Gliomas are the most common primary brain tumors in adults. A diffuse infiltrative growth pattern and high resistance to therapy make them largely incurable, but there are significant differences in the prognosis of patients with different subtypes of glioma. Mutations in isocitrate dehydrogenase (IDH) have been recognized as an important biomarker for glioma classification and a potential therapeutic target. However, current clinical methods for detecting mutated IDH (mIDH) require invasive tissue sampling and cannot be used for follow-up examinations or longitudinal studies. PET imaging could be a promising approach for non-invasive assessment of the IDH status in gliomas, owing to the availability of various mIDH-selective inhibitors as potential leads for the development of PET tracers. In the present review, we summarize the rationale for the development of mIDH-selective PET probes, describe their potential applications beyond the assessment of the IDH status and highlight potential challenges that may complicate tracer development. In addition, we compile the major chemical classes of mIDH-selective inhibitors that have been described to date and briefly consider possible strategies for radiolabeling of the most promising candidates. Where available, we also summarize previous studies with radiolabeled analogs of mIDH inhibitors and assess their suitability for PET imaging in gliomas.

Molecular Pathways Implicated in Radioresistance of Glioblastoma Multiforme: What Is the Role of Extracellular Vesicles?

Glioblastoma multiforme (GBM) is a primary brain tumor that is very aggressive, resistant to treatment, and characterized by a high degree of anaplasia and proliferation. Routine treatment includes ablative surgery, chemotherapy, and radiotherapy. However, GMB rapidly relapses and develops radioresistance. Here, we briefly review the mechanisms underpinning radioresistance and discuss research to stop it and install anti-tumor defenses. Factors that participate in radioresistance are varied and include stem cells, tumor heterogeneity, tumor microenvironment, hypoxia, metabolic reprogramming, the chaperone system, non-coding RNAs, DNA repair, and extracellular vesicles (EVs). We direct our attention toward EVs because they are emerging as promising candidates as diagnostic and prognostication tools and as the basis for developing nanodevices for delivering anti-cancer agents directly into the tumor mass. EVs are relatively easy to obtain and manipulate to endow them with the desired anti-cancer properties and to administer them using minimally invasive procedures. Thus, isolating EVs from a GBM patient, supplying them with the necessary anti-cancer agent and the capability of recognizing a specified tissue-cell target, and reinjecting them into the original donor appears, at this time, as a reachable objective of personalized medicine.

The regulatory mechanisms and inhibitors of isocitrate dehydrogenase 1 in cancer

Reprogramming of energy metabolism is one of the basic characteristics of cancer and has been proved to be an important cancer treatment strategy. Isocitrate dehydrogenases (IDHs) are a class of key proteins in energy metabolism, including IDH1, IDH2, and IDH3, which are involved in the oxidative decarboxylation of isocitrate to yield α-ketoglutarate (α-KG). Mutants of IDH1 or IDH2 can produce d-2-hydroxyglutarate (D-2HG) with α-KG as the substrate, and then mediate the occurrence and development of cancer. At present, no IDH3 mutation has been reported. The results of pan-cancer research showed that IDH1 has a higher mutation frequency and involves more cancer types than IDH2, implying IDH1 as a promising anti-cancer target. Therefore, in this review, we summarized the regulatory mechanisms of IDH1 on cancer from four aspects: metabolic reprogramming, epigenetics, immune microenvironment, and phenotypic changes, which will provide guidance for the understanding of IDH1 and exploring leading-edge targeted treatment strategies. In addition, we also reviewed available IDH1 inhibitors so far. The detailed clinical trial results and diverse structures of preclinical candidates illustrated here will provide a deep insight into the research for the treatment of IDH1-related cancers.

Cerivastatin Synergizes with Trametinib and Enhances Its Efficacy in the Therapy of Uveal Melanoma

BACKGROUND

Metastatic uveal melanoma (MUM) is a highly aggressive, therapy-resistant disease. Driver mutations in Gα-proteins GNAQ and GNA11 activate MAP-kinase and YAP/TAZ pathways of oncogenic signalling. MAP-kinase and MEK-inhibitors do not significantly block MUM progression, likely due to persisting YAP/TAZ signalling. Statins inhibit YAP/TAZ activation by blocking the mevalonate pathway, geranyl-geranylation, and subcellular localisation of the Rho-GTPase. We investigated drugs that affect the YAP/TAZ pathway, valproic acid, verteporfin and statins, in combination with MEK-inhibitor trametinib.

METHODS

We established IC50 values of the individual drugs and monitored the effects of their combinations in terms of proliferation. We selected trametinib and cerivastatin for evaluation of cell cycle and apoptosis. Synergism was detected using isobologram and Chou-Talalay analyses. The most synergistic combination was tested in vivo.

RESULTS

Synergistic concentrations of trametinib and cerivastatin induced a massive arrest of proliferation and cell cycle and enhanced apoptosis, particularly in the monosomic, BAP1-mutated UPMM3 cell line. The combined treatment reduced ERK and AKT phosphorylation, increased the inactive, cytoplasmatic form of YAP and significantly impaired the growth of UM cells with monosomy of chromosome 3 in NSG mice.

CONCLUSION

Statins can potentiate the efficacy of MEK inhibitors in the therapy of UM.

Glutamine Metabolism in Cancer Stem Cells: A Complex Liaison in the Tumor Microenvironment

In this review we focus on the role of glutamine in control of cancer stem cell (CSC) fate. We first provide an overview of glutamine metabolism, and then summarize relevant studies investigating how glutamine metabolism modulates the CSC compartment, concentrating on solid tumors. We schematically describe how glutamine in CSC contributes to several metabolic pathways, such as redox metabolic pathways, ATP production, non-essential aminoacids and nucleotides biosynthesis, and ammonia production. Furthermore, we show that glutamine metabolism is a key regulator of epigenetic modifications in CSC. Finally, we briefly discuss how cancer-associated fibroblasts, adipocytes, and senescent cells in the tumor microenvironment may indirectly influence CSC fate by modulating glutamine availability. We aim to highlight the complexity of glutamine's role in CSC, which supports our knowledge about metabolic heterogeneity within the CSC population.

Upstaging and Downstaging in Gliomas-Clinical Implications for the Fifth Edition of the World Health Organization Classification of Tumors of the Central Nervous System

In 2021, the 5th edition of the WHO Classification of Tumors of the Central Nervous System (WHO-CNS5) was published as the sixth volume of the international standard for brain and spinal cord tumor classification. The most remarkable practical change in the current classification involves grading gliomas according to molecular characterization. IDH mutant (10%) and IDH wild-type tumors (90%) are two different entities that possess unique biological features and various clinical outcomes regarding treatment response and overall survival. This article presents two comparative cases that highlight the clinical importance of these new classification standards. The first clinical case aimed to provide a comprehensive argument for determining the IDH status in tumors initially appearing as low-grade astrocytoma upon histologic examination, thus underlining the importance of the WHO-CNS5. The second case showed the implications of the histologic overdiagnosis of glioblastoma using the previous classification system with a treatment span of 7 years that proceeded through full-dose re-irradiation up to metronomic therapy. The new WHO-CNS5 classification significantly impacted complex neurooncological cases, thus changing the initial approach to a more precise therapeutic management.

TNFα-induced IDH1 hyperacetylation reprograms redox homeostasis and promotes the chemotherapeutic sensitivity

The heterogeneity and drug resistance of colorectal cancer (CRC) often lead to treatment failure. Isocitrate dehydrogenase 1 (IDH1), a rate-limiting enzyme in the tricarboxylic acid cycle, regulates the intracellular redox environment and mediates tumor cell resistance to chemotherapeutic drugs. The aim of this study was to elucidate the mechanism underlying the involvement of IDH1 acetylation in the development of CRC drug resistance under induction of TNFα. We found TNFα disrupted the interaction between SIRT1 and IDH1 and increased the level of acetylation at K115 of IDH1. Hyperacetylation of K115 was accompanied by protein ubiquitination, which increased its susceptibility to degradation compared to IDH1 K115R. TNFα-mediated hyperacetylation of K115 sensitized the CRC cells to 5FU and reduced the NADPH/NADP ratio to that of intracellular ROS. Furthermore, TNFα and 5FU inhibited CRC tumor growth in vivo, while the K115R-expressing tumor tissues developed 5FU resistance. In human CRC tissues, K115 acetylation was positively correlated with TNFα infiltration, and K115 hyperacetylation was associated with favorable prognosis compared to chemotherapy-induced deacetylation. Therefore, TNFα-induced hyperacetylation at the K115 site of IDH1 promotes antitumor redox homeostasis in CRC cells, and can be used as a marker to predict the response of CRC patients to chemotherapy.

Tracing the electron flow in redox metabolism: The appropriate distribution of electrons is essential to maintain redox balance in cancer cells

Cancer cells are characterized by sustained proliferation, which requires a huge demand of fuels to support energy production and biosynthesis. Energy is produced by the oxidation of the fuels during catabolism, and biosynthesis is achieved by the reduction of smaller units or precursors. Therefore, the oxidation-reduction (redox) reactions in cancer cells are more active compared to those in the normal counterparts. The higher activity of redox metabolism also induces a more severe oxidative stress, raising the question of how cancer cells maintain the redox balance. In this review, we overview the redox metabolism of cancer cells in an electron-tracing view. The electrons are derived from the nutrients in the tumor microenvironment and released during catabolism. Most of the electrons are transferred to NAD(P) system and then directed to four destinations: energy production, ROS generation, reductive biosynthesis and antioxidant system. The appropriate distribution of these electrons achieved by the function of redox regulation network is essential to maintain redox homeostasis in cancer cells. Interfering with the electron distribution and disrupting redox balance by targeting the redox regulation network may provide therapeutic implications for cancer treatment.

Wild-Type Isocitrate Dehydrogenase-Dependent Oxidative Decarboxylation and Reductive Carboxylation in Cancer and Their Clinical Significance

The human isocitrate dehydrogenase (IDH) gene encodes for the isoenzymes IDH1, 2, and 3, which catalyze the conversion of isocitrate and α-ketoglutarate (α-KG) and are required for normal mammalian metabolism. Isocitrate dehydrogenase 1 and 2 catalyze the reversible conversion of isocitrate to α-KG. Isocitrate dehydrogenase 3 is the key enzyme that mediates the production of α-KG from isocitrate in the tricarboxylic acid (TCA) cycle. In the TCA cycle, the decarboxylation reaction catalyzed by isocitrate dehydrogenase mediates the conversion of isocitrate to α-KG accompanied by dehydrogenation, a process commonly known as oxidative decarboxylation. The formation of 6-C isocitrate from α-KG and CO₂ catalyzed by IDH is termed reductive carboxylation. This IDH-mediated reversible reaction is of great importance in tumor cells. We outline the role of the various isocitrate dehydrogenase isoforms in cancer, discuss the metabolic implications of interference with IDH, summarize therapeutic interventions targeting changes in IDH expression, and highlight areas for future research.

The roles of IDH1 in tumor metabolism and immunity

IDH1 is a key metabolic enzyme for cellular respiration in the tricarboxylic acid (TCA) cycle that can convert isocitrate into α-ketoglutarate (α-KG) and generate NADPH. The reduction of IDH1 may affect dioxygenase activity and damage the body's detoxification mechanism. Many studies have shown that IDH1 is closely related to the occurrence and development of tumors, and the changes in IDH1 expression levels or gene mutations have appeared in many tumor tissues and produced a series of metabolic and immunity changes at the same time. To better understand the relationship between IDH1 and tumor development, this article reviews the latest advances in IDH1 and tumor metabolism, tumor immunity, IDH1 regulatory mechanisms and IDH1 target inhibitors.

Cardio-Onco-Metabolism - Metabolic vulnerabilities in cancer and the heart

Cancer and cardiovascular diseases (CVDs) are the leading cause of death worldwide. Metabolic remodeling is a hallmark of both cancer and the failing heart. Tumors reprogram metabolism to optimize nutrient utilization and meet increased demands for energy provision, biosynthetic pathways, and proliferation. Shared risk factors for cancer and CVDs suggest intersecting mechanisms for disease pathogenesis and progression. In this review, we aim to highlight the role of metabolic remodeling in cancer and its potential to impair cardiac function. Understanding these mechanisms will help us develop biomarkers, better therapies, and identify patients at risk of developing heart disease after surviving cancer.

Wild-type IDH1 inhibition enhances chemotherapy response in melanoma

BACKGROUND

Alternative treatment strategies in melanoma beyond immunotherapy and mutation-targeted therapy are urgently needed. Wild-type isocitrate dehydrogenase 1 (wtIDH1) has recently been implicated as a metabolic dependency in cancer. The enzyme protects cancer cells under metabolic stress, including nutrient limited conditions in the tumor microenvironment. Specifically, IDH1 generates NADPH to maintain redox homeostasis and produces α-ketoglutarate to support mitochondrial function through anaplerosis. Herein, the role of wtIDH1 in melanoma is further explored.

METHODS

The expression of wtIDH1 was determined by qRT-PCR, and Western blot in melanoma cell lines and the effect of wtIDH1 on metabolic reprogramming in melanoma was interrogated by LC-MS. The impact of wtIDH1 inhibition alone and in combination with chemotherapy was determined in cell culture and mouse melanoma models.

RESULTS

Melanoma patients express higher levels of the wtIDH1 enzyme compared to normal skin tissue, and elevated wtIDH1 expression portends poor patient survival. Knockdown of IDH1 by RNA interference inhibited cell proliferation and migration under low nutrient levels. Suppression of IDH1 expression in melanoma also decreased NADPH and glutathione levels, resulting in increased reactive oxygen species. An FDA-approved inhibitor of mutant IDH1, ivosidenib (AG-120), exhibited potent anti-wtIDH1 properties under low magnesium and nutrient levels, reflective of the tumor microenvironment in natura. Thus, similar findings were replicated in murine models of melanoma. In light of the impact of wtIDH1 inhibition on oxidative stress, enzyme blockade was synergistic with conventional anti-melanoma chemotherapy in pre-clinical models.

CONCLUSIONS

These results demonstrate the clinical potential of wtIDH1 inhibition as a novel and readily available combination treatment strategy for patients with advanced and refractory melanoma. Schematic shows increased wild-type IDH1 expression and activity as an adaptive response to metabolic stress induced by chemotherapy.

IDH1 Promotes Foam Cell Formation by Aggravating Macrophage Ferroptosis

Simple Summary

In our study, the involvement of IDH1 in atherosclerotic foam cells was explored. Inhibiting macrophage ferroptosis and foam cell formation by knocking down IDH1 is a promising study direction for better understanding the occurrence and progression of atherosclerosis, as well as the treatment targets for atherosclerosis.

Abstract

A distinctive feature of ferroptosis is intracellular iron accumulation and the impairment of antioxidant capacity, resulting in a lethal accumulation of lipid peroxides leading to cell death. This study was conducted to determine whether inhibiting isocitrate dehydrogenase 1 (IDH1) may help to prevent foam cell formation by reducing oxidized low-density lipoprotein (ox-LDL)-induced ferroptosis in macrophages and activating nuclear factor erythroid 2-related factor 2 (NRF2). Gene expression profiling (GSE70126 and GSE70619) revealed 21 significantly different genes, and subsequent bioinformatics research revealed that ferroptosis and IDH1 play essential roles in foam cell production. We also confirmed that ox-LDL elevates macrophage ferroptosis and IDH1 protein levels considerably as compared with controls. Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, reduced ox-LDL-induced elevated Fe²⁺ levels, lipid peroxidation (LPO) buildup, lactate dehydrogenase (LDH) buildup, glutathione (GSH) depletion, glutathione peroxidase 4 (GPX4), ferritin heavy polypeptide 1 (FTH1), and solute carrier family 7 member 11 (SLC7A11) protein downregulation. More crucially, inhibiting IDH1 reduced Fe²⁺ overload, lipid peroxidation, LDH, and glutathione depletion, and elevated GPX4, FTH1, and SLC7A11 protein expression, resulting in a reduction in ox-LDL-induced macrophage ferroptosis. IDH1 inhibition suppressed ox-LDL-induced macrophage damage and apoptosis while raising NRF2 protein levels. We have demonstrated that inhibiting IDH1 reduces ox-LDL-induced ferroptosis and foam cell formation in macrophages, implying that IDH1 may be an important molecule regulating foam cell formation and may be a promising molecular target for the treatment of atherosclerosis.

Low expression of isocitrate dehydrogenase 1 (IDH1) R132H is associated with advanced pathological features in laryngeal squamous cell carcinoma

INTRODUCTION

Recent developments in genomic sequencing have led to the identification of somatic mutations in isocitrate dehydrogenase 1 (IDH1) in various malignancies. IDH1 R132H is the most common mutation of IDH1, which affects codon 132 and results in the conversion of amino acid residue arginine (R) to histidine (H). This study is designed to evaluate the association between the expression of IDH1 R132H and clinicopathological characteristics in laryngeal squamous cell carcinoma (LSCC).

METHODS

The expression pattern and clinical significance of IDH1 R132H were investigated in tissue microarrays (TMAs) of 50 LSCC tumors as well as adjacent normal tissues using immunohistochemistry. Then the exons of the 12 tumor samples with negative/weak positive staining were sequenced by applying polymerase chain reaction (PCR).

RESULTS

The results demonstrated that the cytoplasmic expression of IDH1 R132H was downregulated in tumor cells compared to adjacent normal tissues. A statistically significant association was found between a low level of cytoplasmic expression of IDH1 R132H protein and an increase in histological grade (p < 0.001), perineural invasion (p = 0.019), and lymph node involvement (p < 0.001). The exon4 sequencing results showed that only one sample was positive for IDH1 R132H mutation. IDH1 R132H expression was observed in 39 (78.0%) LSCC samples.

CONCLUSION

These findings indicate that low cytoplasmic expression of IDH1 R132H may have clinical significance in LSCC patients and is associated with more aggressive tumor behavior and progression of the disease, which can help improve potential treatment in patients with LSCC. Further investigations are needed to understand the biological function of IDH1 R132H and larger sample size to confirm our findings.

Nanotherapeutic treatment of the invasive glioblastoma tumor microenvironment

Glioblastoma (GBM) is the most common malignant adult brain cancer with no curative treatment strategy. A significant hurdle in GBM treatment is effective therapeutic delivery to the brain-invading tumor cells that remain following surgery within functioning brain regions. Developing therapies that can either directly target these brain-invading tumor cells or act on other cell types and molecular processes supporting tumor cell invasion and recurrence are essential steps in advancing new treatments in the clinic. This review highlights some of the drug delivery strategies and nanotherapeutic technologies that are designed to target brain-invading GBM cells or non-neoplastic, invasion-supporting cells residing within the GBM tumor microenvironment.

Combinatorial approaches to effective therapy in glioblastoma (GBM): Current status and what the future holds

The aggressive and recurrent nature of glioblastoma is multifactorial and has been attributed to its biological heterogeneity, dysfunctional metabolic signaling pathways, rigid blood-brain barrier, inherent resistance to standard therapy due to the stemness property of the gliomas cells, immunosuppressive tumor microenvironment, hypoxia and neoangiogenesis which are very well orchestrated and create the tumor's own highly pro-tumorigenic milieu. Once the relay of events starts amongst these components, eventually it becomes difficult to control the cascade using only the balanced contemporary care of treatment consisting of maximal resection, radiotherapy and chemotherapy with temozolamide. Over the past few decades, implementation of contemporary treatment modalities has shown benefit to some extent, but no significant overall survival benefit is achieved. Therefore, there is an unmet need for advanced multifaceted combinatorial strategies. Recent advances in molecular biology, development of innovative therapeutics and novel delivery platforms over the years has resulted in a paradigm shift in gliomas therapeutics. Decades of research has led to emergence of several treatment molecules, including immunotherapies such as immune checkpoint blockade, oncolytic virotherapy, adoptive cell therapy, nanoparticles, CED and BNCT, each with the unique proficiency to overcome the mentioned challenges, present research. Recent years are seeing innovative combinatorial strategies to overcome the multifactorial resistance put forth by the GBM cell and its TME. This review discusses the contemporary and the investigational combinatorial strategies being employed to treat GBM and summarizes the evidence accumulated till date.

Metabolic Rewiring in Glioblastoma Cancer: EGFR, IDH and Beyond

Glioblastoma multiforme (GBM), a highly invasive and incurable tumor, is the humans’ foremost, commonest, and deadliest brain cancer. As in other cancers, distinct combinations of genetic alterations (GA) in GBM induce a diversity of metabolic phenotypes resulting in enhanced malignancy and altered sensitivity to current therapies. Furthermore, GA as a hallmark of cancer, dysregulated cell metabolism in GBM has been recently linked to the acquired GA. Indeed, Numerous point mutations and copy number variations have been shown to drive glioma cells’ metabolic state, affecting tumor growth and patient outcomes. Among the most common, IDH mutations, EGFR amplification, mutation, PTEN loss, and MGMT promoter mutation have emerged as key patterns associated with upregulated glycolysis and OXPHOS glutamine addiction and altered lipid metabolism in GBM. Therefore, current Advances in cancer genetic and metabolic profiling have yielded mechanistic insights into the metabolism rewiring of GBM and provided potential avenues for improved therapeutic modalities. Accordingly, actionable metabolic dependencies are currently used to design new treatments for patients with glioblastoma. Herein, we capture the current knowledge of genetic alterations in GBM, provide a detailed understanding of the alterations in metabolic pathways, and discuss their relevance in GBM therapy.

Computational study on novel natural compound inhibitor targeting IDH1_R132H

Isocitrate dehydrogenases (IDH) catalyze the oxidative decarboxylation of isocitrate to 2-oxoglutarate. IDH1 mutation has been reported in various tumors especially Cholangiocarcinoma, while the IDH1_R132H is reported to be the most common mutation of IDH1. IDH1_R132H inhibitors are effective anti-cancer drugs and have shown significant therapeutic effects in clinical. In this study, two novel natural compounds were identified to combine respectively with IDH1_R132H with a stronger binding force with conductive to interaction energy. They also showed low toxicity potential. Molecular dynamics simulation analysis demonstrated that the candidate ligands-IDH1_R132H complexes is stable in natural circumstances with favorable potential energy. Thus, Styraxlignolide F and Tremulacin were screened as promising IDH1_R132H inhibitors. We provide a solid foundation for the design and development of IDH1_R132H targeted drugs.

Glioblastoma: Current Status, Emerging Targets, and Recent Advances

Glioblastoma (GBM) is a highly malignant brain tumor characterized by a heterogeneous population of genetically unstable and highly infiltrative cells that are resistant to chemotherapy. Although substantial efforts have been invested in the field of anti-GBM drug discovery in the past decade, success has primarily been confined to the preclinical level, and clinical studies have often been hampered due to efficacy-, selectivity-, or physicochemical property-related issues. Thus, expansion of the list of molecular targets coupled with a pragmatic design of new small-molecule inhibitors with central nervous system (CNS)-penetrating ability is required to steer the wheels of anti-GBM drug discovery endeavors. This Perspective presents various aspects of drug discovery (challenges in GBM drug discovery and delivery, therapeutic targets, and agents under clinical investigation). The comprehensively covered sections include the recent medicinal chemistry campaigns embarked upon to validate the potential of numerous enzymes/proteins/receptors as therapeutic targets in GBM.

Using AI-Based Evolutionary Algorithms to Elucidate Adult Brain Tumor (Glioma) Etiology Associated with IDH1 for Therapeutic Target Identification

Adult brain tumors (glioma) represent a cancer of unmet need where standard-of-care is non-curative; thus, new therapies are urgently needed. It is unclear whether isocitrate dehydrogenases (IDH1/2) when not mutated have any role in gliomagenesis or tumor growth. Nevertheless, IDH1 is overexpressed in glioblastoma (GBM), which could impact upon cellular metabolism and epigenetic reprogramming. This study characterizes IDH1 expression and associated genes and pathways. A novel biomarker discovery pipeline using artificial intelligence (evolutionary algorithms) was employed to analyze IDH-wildtype adult gliomas from the TCGA LGG-GBM cohort. Ninety genes whose expression correlated with IDH1 expression were identified from: (1) All gliomas, (2) primary GBM, and (3) recurrent GBM tumors. Genes were overrepresented in ubiquitin-mediated proteolysis, focal adhesion, mTOR signaling, and pyruvate metabolism pathways. Other non-enriched pathways included O-glycan biosynthesis, notch signaling, and signaling regulating stem cell pluripotency (PCGF3). Potential prognostic (TSPYL2, JAKMIP1, CIT, TMTC1) and two diagnostic (MINK1, PLEKHM3) biomarkers were downregulated in GBM. Their gene expression and methylation were negatively and positively correlated with IDH1 expression, respectively. Two diagnostic biomarkers (BZW1, RCF2) showed the opposite trend. Prognostic genes were not impacted by high frequencies of molecular alterations and only one (TMTC1) could be validated in another cohort. Genes with mechanistic links to IDH1 were involved in brain neuronal development, cell proliferation, cytokinesis, and O-mannosylation as well as tumor suppression and anaplerosis. Results highlight metabolic vulnerabilities and therapeutic targets for use in future clinical trials.

Limited nutrient availability in the tumor microenvironment renders pancreatic tumors sensitive to allosteric IDH1 inhibitors

Nutrient-deprived conditions in the tumor microenvironment (TME) restrain cancer cell viability due to increased free radicals and reduced energy production. In pancreatic cancer cells a cytosolic metabolic enzyme, wild-type isocitrate dehydrogenase 1 (wtIDH1), enables adaptation to these conditions. Under nutrient starvation, wtIDH1 oxidizes isocitrate to generate α-ketoglutarate (αKG) for anaplerosis and NADPH to support antioxidant defense. In this study, we show that allosteric inhibitors of mutant IDH1 (mIDH1) are potent wtIDH1 inhibitors under conditions present in the TME. We demonstrate that low magnesium levels facilitate allosteric inhibition of wtIDH1, which is lethal to cancer cells when nutrients are limited. Furthermore, the Food & Drug Administration (FDA)-approved mIDH1 inhibitor ivosidenib (AG-120) dramatically inhibited tumor growth in preclinical models of pancreatic cancer, highlighting this approach as a potential therapeutic strategy against wild-type IDH1 cancers.

Multidrug Resistance in Cancer: Understanding Molecular Mechanisms, Immunoprevention and Therapeutic Approaches

Cancer is one of the leading causes of death worldwide. Several treatments are available for cancer treatment, but many treatment methods are ineffective against multidrug-resistant cancer. Multidrug resistance (MDR) represents a major obstacle to effective therapeutic interventions against cancer. This review describes the known MDR mechanisms in cancer cells and discusses ongoing laboratory approaches and novel therapeutic strategies that aim to inhibit, circumvent, or reverse MDR development in various cancer types. In this review, we discuss both intrinsic and acquired drug resistance, in addition to highlighting hypoxia- and autophagy-mediated drug resistance mechanisms. Several factors, including individual genetic differences, such as mutations, altered epigenetics, enhanced drug efflux, cell death inhibition, and various other molecular and cellular mechanisms, are responsible for the development of resistance against anticancer agents. Drug resistance can also depend on cellular autophagic and hypoxic status. The expression of drug-resistant genes and the regulatory mechanisms that determine drug resistance are also discussed. Methods to circumvent MDR, including immunoprevention, the use of microparticles and nanomedicine might result in better strategies for fighting cancer.

Silybin suppresses ovarian cancer cell proliferation by inhibiting isocitrate dehydrogenase 1 activity

Metabolic reprogramming is a sign of malignant tumors, and targeting the metabolism of tumor cells has become a promising therapeutic approach. Here, we report that Silybin (a nontoxic flavonoid commonly used for liver protection) exhibits prominent anti‐tumor effects on human ovarian cancer cells. Treatment of an ovarian cancer cell line with Silybin interfered with glutamine metabolism and the tricarboxylic acid cycle. We applied the drug affinity responsive target stability approach to show that Silybin binds to isocitrate dehydrogenase 1 (IDH1). This combination leads to reduced phosphorylation of IDH1 and inhibits enzyme activity. IDH1 dysfunction significantly increases the ratio of NADP/NADPH in the cell, causing an increase in reactive oxygen species generation. Immunohistochemistry demonstrated that IDH1 was increased in ovarian cancer samples compared with normal para‐tumoral tissues. Xenograft murine experiments indicated that Silybin administered orally suppressed the growth of the tumor formed by ovarian cancer cells. In combination, our data strongly suggest that Silybin targets IDH1 in ovarian cancer cells and may be a novel treatment candidate.

Profiling the Effect of Targeting Wild Isocitrate Dehydrogenase 1 (IDH1) on the Cellular Metabolome of Leukemic Cells

Leukemia is one of the most common primary malignancies of the hematologic system in both children and adults and remains a largely incurable or relapsing disease. The elucidation of disease subtypes based on mutational profiling has not improved clinical outcomes. IDH1/2 are critical enzymes of the TCA cycle that produces α-ketoglutarate (αKG). However, their mutated version is well reported in various cancer types, including leukemia, which produces D-2 hydroxyglutarate (D-2HG), an oncometabolite. Recently, some studies have shown that wild-type IDH1 is highly expressed in non-small cell lung carcinoma (NSCLC), primary glioblastomas (GBM), and several hematological malignancies and is correlated with disease progression. This work shows that the treatment of wild-type IDH1 leukemia cells with a specific IDH1 inhibitor shifted leukemic cells toward glycolysis from the oxidative phosphorylation (OXPHOS) phenotype. We also noticed a reduction in αKG in treated cells, possibly suggesting the inhibition of IDH1 enzymatic activity. Furthermore, we found that IDH1 inhibition reduced the metabolites related to one-carbon metabolism, which is essential for maintaining global methylation in leukemic cells. Finally, we observed that metabolic alteration in IDH1 inhibitor-treated leukemic cells promoted reactive oxygen species (ROS) formation and the loss of mitochondrial membrane potential, leading to apoptosis in leukemic cells. We showed that targeting wild-type IDH1 leukemic cells promotes metabolic alterations that can be exploited for combination therapies for a better outcome.

The Potential Role of Exosomal Proteins in Prostate Cancer

Prostate cancer is the most prevalent malignant tumor in men across developed countries. Traditional diagnostic and therapeutic methods for this tumor have become increasingly difficult to adapt to today’s medical philosophy, thus compromising early detection, diagnosis, and treatment. Prospecting for new diagnostic markers and therapeutic targets has become a hot topic in today’s research. Notably, exosomes, small vesicles characterized by a phospholipid bilayer structure released by cells that is capable of delivering different types of cargo that target specific cells to regulate biological properties, have been extensively studied. Exosomes composition, coupled with their interactions with cells make them multifaceted regulators in cancer development. Numerous studies have described the role of prostate cancer-derived exosomal proteins in diagnosis and treatment of prostate cancer. However, so far, there is no relevant literature to systematically summarize its role in tumors, which brings obstacles to the later research of related proteins. In this review, we summarize exosomal proteins derived from prostate cancer from different sources and summarize their roles in tumor development and drug resistance.

Alterations in Molecular Profiles Affecting Glioblastoma Resistance to Radiochemotherapy: Where Does the Good Go?

Simple Summary

Glioblastoma is a type of brain cancer that remains incurable. Despite multiple past and ongoing preclinical studies and clinical trials, involving adjuvants to the conventional therapy and based on molecular targeting, no relevant benefit for patients’ survival has been achieved so far. The current first-line treatment regimen is based on ionizing radiation and the monoalkylating compound, temozolomide, and has been administered for more than 15 years. Glioblastoma is extremely resistant to most agents due to a mutational background that elicits quick response to insults and adapts to microenvironmental and metabolic changes. Here, we present the most recent evidence concerning the molecular features and their alterations governing pathways involved in GBM response to the standard radio-chemotherapy and discuss how they collaborate with acquired GBM’s resistance.

Abstract

Glioblastoma multiforme (GBM) is a brain tumor characterized by high heterogeneity, diffuse infiltration, aggressiveness, and formation of recurrences. Patients with this kind of tumor suffer from cognitive, emotional, and behavioral problems, beyond exhibiting dismal survival rates. Current treatment comprises surgery, radiotherapy, and chemotherapy with the methylating agent, temozolomide (TMZ). GBMs harbor intrinsic mutations involving major pathways that elicit the cells to evade cell death, adapt to the genotoxic stress, and regrow. Ionizing radiation and TMZ induce, for the most part, DNA damage repair, autophagy, stemness, and senescence, whereas only a small fraction of GBM cells undergoes treatment-induced apoptosis. Particularly upon TMZ exposure, most of the GBM cells undergo cellular senescence. Increased DNA repair attenuates the agent-induced cytotoxicity; autophagy functions as a pro-survival mechanism, protecting the cells from damage and facilitating the cells to have energy to grow. Stemness grants the cells capacity to repopulate the tumor, and senescence triggers an inflammatory microenvironment favorable to transformation. Here, we highlight this mutational background and its interference with the response to the standard radiochemotherapy. We discuss the most relevant and recent evidence obtained from the studies revealing the molecular mechanisms that lead these cells to be resistant and indicate some future perspectives on combating this incurable tumor.

The role of ROS in tumour development and progression

Eukaryotic cells have developed complex systems to regulate the production and response to reactive oxygen species (ROS). Different ROS control diverse aspects of cell behaviour from signalling to death, and deregulation of ROS production and ROS limitation pathways are common features of cancer cells. ROS also function to modulate the tumour environment, affecting the various stromal cells that provide metabolic support, a blood supply and immune responses to the tumour. Although it is clear that ROS play important roles during tumorigenesis, it has been difficult to reliably predict the effect of ROS modulating therapies. We now understand that the responses to ROS are highly complex and dependent on multiple factors, including the types, levels, localization and persistence of ROS, as well as the origin, environment and stage of the tumours themselves. This increasing understanding of the complexity of ROS in malignancies will be key to unlocking the potential of ROS-targeting therapies for cancer treatment.