TGF-β-induced hCG-β regulates redox homeostasis in glioma cells

GLIO-Select: Machine Learning-Based Feature Selection and Weighting of Tissue and Serum Proteomic and Metabolomic Data Uncovers Sex Differences in Glioblastoma

Glioblastoma (GBM) is a fatal brain cancer known for its rapid and aggressive growth, with some studies indicating that females may have better survival outcomes compared to males. While sex differences in GBM have been observed, the underlying biological mechanisms remain poorly understood. Feature selection can lead to the identification of discriminative key biomarkers by reducing dimensionality from high-dimensional medical datasets to improve machine learning model performance, explainability, and interpretability. Feature selection can uncover unique sex-specific biomarkers, determinants, and molecular profiles in patients with GBM. We analyzed high-dimensional proteomic and metabolomic profiles from serum biospecimens obtained from 109 patients with pathology-proven glioblastoma (GBM) on NIH IRB-approved protocols with full clinical annotation (local dataset). Serum proteomic analysis was performed using Somalogic aptamer-based technology (measuring 7289 proteins) and serum metabolome analysis using the University of Florida's SECIM (Southeast Center for Integrated Metabolomics) platform (measuring 6015 metabolites). Machine learning-based feature selection was employed to identify proteins and metabolites associated with male and female labels in high-dimensional datasets. Results were compared to publicly available proteomic and metabolomic datasets (CPTAC and TCGA) using the same methodology and TCGA data previously structured for glioma grading. Employing a machine learning-based and hybrid feature selection approach, utilizing both LASSO and mRMR, in conjunction with a rank-based weighting method (i.e., GLIO-Select), we linked proteomic and metabolomic data to clinical data for the purposes of feature reduction to identify molecular biomarkers associated with biological sex in patients with GBM and used a separate TCGA set to explore possible linkages between biological sex and mutations associated with tumor grading. Serum proteomic and metabolomic data identified several hundred features that were associated with the male/female class label in the GBM datasets. Using the local serum-based dataset of 109 patients, 17 features (100% ACC) and 16 features (92% ACC) were identified for the proteomic and metabolomic datasets, respectively. Using the CPTAC tissue-based dataset (8828 proteomic and 59 metabolomic features), 5 features (99% ACC) and 13 features (80% ACC) were identified for the proteomic and metabolomic datasets, respectively. The proteomic data serum or tissue (CPTAC) achieved the highest accuracy rates (100% and 99%, respectively), followed by serum metabolome and tissue metabolome. The local serum data yielded several clinically known features (PSA, PZP, HCG, and FSH) which were distinct from CPTAC tissue data (RPS4Y1 and DDX3Y), both providing methodological validation, with PZP and defensins (DEFA3 and DEFB4A) representing shared proteomic features between serum and tissue. Metabolomic features shared between serum and tissue were homocysteine and pantothenic acid. Several signals emerged that are known to be associated with glioma or GBM but not previously known to be associated with biological sex, requiring further research, as well as several novel signals that were previously not linked to either biological sex or glioma. EGFR, FAT4, and BCOR were the three features associated with 64% ACC using the TCGA glioma grading set. GLIO-Select shows remarkable results in reducing feature dimensionality when different types of datasets (e.g., serum and tissue-based) were used for our analyses. The proposed approach successfully reduced relevant features to less than twenty biomarkers for each GBM dataset. Serum biospecimens appear to be highly effective for identifying biologically relevant sex differences in GBM. These findings suggest that serum-based noninvasive biospecimen-based analyses may provide more accurate and clinically detailed insights into sex as a biological variable (SABV) as compared to other biospecimens, with several signals linking sex differences and glioma pathology via immune response, amino acid metabolism, and cancer hallmark signals requiring further research. Our results underscore the importance of biospecimen choice and feature selection in enhancing the interpretation of omics data for understanding sex-based differences in GBM. This discovery holds significant potential for enhancing personalized treatment plans and patient outcomes.

KYP-2047, an Inhibitor of Prolyl-Oligopeptidase, Reduces GlioBlastoma Proliferation through Angiogenesis and Apoptosis Modulation

Simple Summary

Glioblastoma (GB) is the most aggressive brain tumor characterized by necrosis, excessive proliferation, and invasiveness. Despite relevant progress in conventional treatments, the survival rate for patients with GB remains low. The present study investigated the potential effect of KYP-2047, an inhibitor of the prolyl-oligopeptidase (POP or PREP), in an in vivo U87-xenograft model and in an in vitro study on human GB cells. This study demonstrated the abilities of KYP-2047 to counteract and reduce GB progression through angiogenesis and apoptosis modulation.

Abstract

Glioblastoma (GB) is the most aggressive tumor of the central nervous system (CNS), characterized by excessive proliferation, necrosis and invasiveness. The survival rate for patients with GB still remains low. Angiogenesis and apoptosis play a key role in the development of GB. Thus, the modulation of angiogenesis and apoptosis processes represent a possible strategy to counteract GB progression. This study aimed to investigate the potential effect of KYP-2047, an inhibitor of the prolyl-oligopeptidase (POP), known to modulate angiogenesis, in an in vivo U87-xenograft model and in an in vitro study on human GB cells. Our results showed that KYP-2047 at doses of 2.5 mg/kg and 5 mg/kg was able to reduce tumor burden in the xenograft-model. Moreover, KYP-2047 significantly reduced vascular endothelial-growth-factor (VEGF), angiopoietins (Ang) and endothelial-nitric-oxide synthase (eNOS) expression. In vitro study revealed that KYP-2047 at different concentrations reduced GB cells’ viability. Additionally, KYP-2047 at the concentrations of 50 µM and 100 µM was able to increase the pro-apoptotic protein Bax, p53 and caspase-3 expression whereas Bcl-2 expression was reduced. Thus, KYP-2047 could represent a potential therapeutic treatment to counteract or reduce GB progression, thanks its abilities to modulate angiogenesis and apoptosis pathways.

Current Perspective on the Natural Compounds and Drug Delivery Techniques in Glioblastoma Multiforme

Simple Summary

Glioblastoma multiforme (GBM) is one of the belligerent neoplasia that metastasize to other brain regions and invade nearby healthy tissues. However, the treatments available are associated with some limitations, such as high variations in solid tumors and deregulation of multiple cellular pathways. The heterogeneity of the GBM tumor and its aggressive infiltration into the nearby tissues makes it difficult to treat. Hence, the development of multimodality therapy that can be more effective, novel, with fewer side effects, improving the prognosis for GBM is highly desired. This review evaluated the use of natural phytoconstituents as an alternative for the development of a new therapeutic strategy. The key aspects of GBM and the potential of drug delivery techniques were also assessed, for tumor site delivery with limited side-effects. These efforts will help to provide better therapeutic options to combat GBM in future.

Abstract

Glioblastoma multiforme (GBM) is one of the debilitating brain tumors, being associated with extremely poor prognosis and short median patient survival. GBM is associated with complex pathogenesis with alterations in various cellular signaling events, that participate in cell proliferation and survival. The impairment in cellular redox pathways leads to tumorigenesis. The current standard pharmacological regimen available for glioblastomas, such as radiotherapy and surgical resection following treatment with chemotherapeutic drug temozolomide, remains fatal, due to drug resistance, metastasis and tumor recurrence. Thus, the demand for an effective therapeutic strategy for GBM remains elusive. Hopefully, novel products from natural compounds are suggested as possible solutions. They protect glial cells by reducing oxidative stress and neuroinflammation, inhibiting proliferation, inducing apoptosis, inhibiting pro-oncogene events and intensifying the potent anti-tumor therapies. Targeting aberrant cellular pathways in the amelioration of GBM could promote the development of new therapeutic options that improve patient quality of life and extend survival. Consequently, our review emphasizes several natural compounds in GBM treatment. We also assessed the potential of drug delivery techniques such as nanoparticles, Gliadel wafers and drug delivery using cellular carriers which could lead to a novel path for the obliteration of GBM.

ROS and TGFβ: from pancreatic tumour growth to metastasis

Transforming growth factor β (TGFβ) signalling pathway switches between anti-tumorigenic function at early stages of cancer formation and pro-tumorigenic effects at later stages promoting cancer metastasis. A similar contrasting role has been uncovered for reactive oxygen species (ROS) in pancreatic tumorigenesis. Down-regulation of ROS favours premalignant tumour development, while increasing ROS level in pancreatic ductal adenocarcinoma (PDAC) enhances metastasis. Given the functional resemblance, we propose that ROS-mediated processes converge with the spatial and temporal activation of TGFβ signalling and thereby differentially impact early tumour growth versus metastatic dissemination. TGFβ signalling and ROS could extensively orchestrate cellular processes and this concerted function can be utilized by cancer cells to facilitate their malignancy. In this article, we revisit the interplay of canonical and non-canonical TGFβ signalling with ROS throughout pancreatic tumorigenesis and metastasis. We also discuss recent insight that helps to understand their conflicting effects on different stages of tumour development. These considerations open new strategies in cancer therapeutics.

Emerging Roles and Therapeutic Interventions of Aerobic Glycolysis in Glioma

Glioma is the most common type of intracranial malignant tumor, with a great recurrence rate due to its infiltrative growth, treatment resistance, intra- and intertumoral genetic heterogeneity. Recently, accumulating studies have illustrated that activated aerobic glycolysis participated in various cellular and clinical activities of glioma, thus influencing the efficacy of radiotherapy and chemotherapy. However, the glycolytic process is too complicated and ambiguous to serve as a novel therapy for glioma. In this review, we generalized the implication of key enzymes, glucose transporters (GLUTs), signalings and transcription factors in the glycolytic process of glioma. In addition, we summarized therapeutic interventions via the above aspects and discussed promising clinical applications for glioma.

Down-regulation of TFAM increases the sensitivity of tumour cells to radiation via p53/TIGAR signalling pathway

Mitochondrial transcription factor A (TFAM) is a key regulator of mitochondria biogenesis. Previous studies confirmed that reduced TFAM expression sensitized tumours cells to chemical therapy reagents and ionizing irradiation (IR). However, the underlying mechanisms remain largely unknown. In this study, we identified that decreased expression of TFAM impaired the proliferation of tumour cells by inducing G1/S phase arrest and reducing the expression of E2F1, phospo-Rb, PCNA and TK1. Furthermore, we proved that knockdown of TFAM enhanced the interaction between p53 and MDM2, resulting in decreased expression of p53 and the downstream target TIGAR, and thus leading to elevated level of mitochondrial superoxide and DNA double-strand break (DSB) which were exacerbated when treated the cell with ionizing radiation. Those indicated that knockdown of TFAM could aggravate radiation induced DSB levels through affecting the production of mitochondria derived reactive oxygen species. Our current work proposed a new mechanism that TFAM through p53/TIGAR signalling to regulate the sensitivity of tumour cells to ionizing radiation. This indicated that TFAM might be a potential target for increasing the sensitization of cancer cells to radiotherapy.

Effectors of thioredoxin reductase: Brevetoxins and manumycin-A

The activities of two effectors, brevetoxin (PbTx) and manumycin-A (Man-A), of thioredoxin reductase (TrxR) have been evaluated against a series of fourteen TrxR orthologs originating from mammals, insects and protists and several mutants. Man-A, a molecule with numerous electrophilic sites, forms a covalent adduct with most selenocystine (Sec)-containing TrxR enzymes. The evidence also demonstrates that Man-A can form covalent adducts with some non-Sec-containing enzymes. The activities of TrxR enzymes towards various substrates are moderated by Man-A either positively or negatively depending on the enzyme. In general, the reduction of substrates by Sec-containing TrxR is inhibited and NADPH oxidase activity is activated. For non-Sec-containing TrxR the effect of Man-A on the reduction of substrates is variable, but NADPH oxidase activity can be activated even in the absence of covalent modification of TrxR. The effect of PbTx is less pronounced. A smaller subset of enzymes is affected by PbTx. With a single exception, the activities of most of this subset are activated. Although both PbTx variants can react with selenocysteine, a stable covalent adduct is not formed with any of the TrxR enzymes. The key findings from this work are (i) the identification of an alternate mechanism of toxicity for the algal toxin brevetoxin (ii) the demonstration that covalent modification of TrxR is not a prerequisite for the activation of NADPH oxidase activity of TrxR and (iii) the identification of an inhibitor which can discriminate between cytosolic and mitochondrial TrxR.

The Delicate Equilibrium between Oxidants and Antioxidants in Brain Glioma

Gliomas are the most frequent brain tumors in the adult population and unfortunately the adjuvant therapies are not effective. Brain tumorigenesis has been related both to the increased levels of free radicals as inductors of severe damages in healthy cells, but also with the reduced response of endogenous enzyme and non-enzymatic antioxidant defenses. In turn, both processes induce the change to malignant cells. In this review, we analyzed the role of the imbalance between free radicals production and antioxidant mechanism in the development and progression of gliomas but also the influence of redox status on the two major distinctive forms of programmed cell death related to cancer: apoptosis and autophagy. These data may be the reference to the development of new pharmacological options based on redox microenvironment for glioma treatment.

Manumycin A Is a Potent Inhibitor of Mammalian Thioredoxin Reductase-1 (TrxR-1)

The anticancer effect of manumycin A (Man A) has been attributed to the inhibition of farnesyl transferase (FTase), an enzyme that is responsible for post-translational modification of Ras proteins. However, we have discovered that Man A inhibits mammalian cytosolic thioredoxin reductase 1 (TrxR-1) in a time-dependent manner, with an IC₅₀ of 272 nM with preincubation and 1586 nM without preincubation. The inhibition of TrxR-1 by Man A is irreversible and is the result of a covalent interaction between Man A and TrxR-1. Evidence presented herein demonstrates that Man A forms a Michael adduct with the selenocysteine residue, which is located in the C-terminal redox center of TrxR-1. Inhibitors of TrxR-1, which act through this mechanism, convert TrxR-1 into a SecTRAP, which utilizes NADPH to reduce oxygen to superoxide radical anion (O₂^-•).

Lowered reference limits for hCG improve follow-up of patients with hCG-producing tumors

BACKGROUND

Human Chorionic Gonadotropin (hCG) is produced by germ cell tumors, but can also be elevated in benign conditions such as primary hypogonadism, where hCG is produced by the pituitary gland. In our experience, the reference limits for hCG (Elecsys hCG+β-assay, Roche Diagnostics), were unnecessarily high and did not reflect levels encountered in clinical practice. We wanted to establish new reference limits to increase the clinical utility of the hCG-assay.

METHODS

We analysed hCG in serum samples from a healthy adult population and in a cohort of testicular cancer survivors. The gonadotropins LH and FSH were measured in the cohort and in a selection of the reference population to assess gonadal function.

RESULTS

We found low hCG levels for all men and women <45years (97.5 percentiles 0.1 and 0.2IU/L, respectively) from the healthy population (n=795) having normal FSH and LH. Due to assay limitations, we suggest a common reference limit of <0.3IU/L. For the age group ≥45, the 97.5 percentiles in the healthy population were 0.5IU/L for men and 6.0IU/L for women. In all subjects from both the reference population and the cohort (n=732), hCG levels exceeding the reference limit could be fully explained by reduced gonadal function indicated by elevated LH and FSH levels.

CONCLUSION

The Elecsys hCG+β-assay should have lower reference limits than recommended by the manufacturer, with important implications for tumor follow-up. Elevated hCG is rare with intact gonadal function, both in a normal population and among survivors of testicular cancer, and should lead to further investigations when encountered in clinical practice.

A low toxic synthetic dendrimer conjugated podophyllotoxin nanodevice with potent antitumor activity against the DMBA/TPA induced mouse skin carcinogenesis model

D-PODO in tumor-bearing mice revealed a 50%–60% inhibition of skin tumor formation and reduced toxicity compared to PODO.