Targeting autophagy to sensitive glioma to temozolomide treatment

Autophagy as a Therapeutic Target in Breast Tumors: The Cancer stem cell perspective

Breast cancer is a heterogeneous disease, with a subpopulation of tumor cells known as breast cancer stem cells (BCSCs) with self-renewal and differentiation abilities that play a critical role in tumor initiation, progression, and therapy resistance. The tumor microenvironment (TME) is a complex area where diverse cancer cells reside creating a highly interactive environment with secreted factors, and the extracellular matrix. Autophagy, a cellular self-digestion process, influences dynamic cellular processes in the tumor TME integrating diverse signals that regulate tumor development and heterogeneity. Autophagy acts as a double-edged sword in the breast TME, with both tumor-promoting and tumor-suppressing roles. Autophagy promotes breast tumorigenesis by regulating tumor cell survival, migration and invasion, metabolic reprogramming, and epithelial-mesenchymal transition (EMT). BCSCs harness autophagy to maintain stemness properties, evade immune surveillance, and resist therapeutic interventions. Conversely, excessive, or dysregulated autophagy may lead to BCSC differentiation or cell death, offering a potential avenue for therapeutic exploration. The molecular mechanisms that regulate autophagy in BCSCs including the mammalian target of rapamycin (mTOR), AMPK, and Beclin-1 signaling pathways may be potential targets for pharmacological intervention in breast cancer. This review provides a comprehensive overview of the relationship between autophagy and BCSCs, highlighting recent advancements in our understanding of their interplay. We also discuss the current state of autophagy-targeting agents and their preclinical and clinical development in BCSCs.

Enhancing Temozolomide (TMZ) chemosensitivity using CRISPR-dCas9-mediated downregulation of O6-methylguanine DNA methyltransferase (MGMT)

PURPOSE

Glioblastoma (GBM) stands out as the most prevalent and aggressive intracranial tumor, notorious for its poor prognosis. The current standard-of-care for GBM patients involves surgical resection followed by radiotherapy, combined with concurrent and adjuvant chemotherapy using Temozolomide (TMZ). The effectiveness of TMZ primarily relies on the activity of O6-methylguanine DNA methyltransferase (MGMT), which removes alkyl adducts from the O6 position of guanine at the DNA level, thereby counteracting the toxic effects of TMZ.

METHOD

In this study, we employed fusions of catalytically-inactive Cas9 (dCas9) to DNA methyltransferases (dCas9-DNMT3A) to selectively downregulation MGMT transcription by inducing methylation at MGMT promoter and K-M enhancer.

RESULT

Our findings demonstrate a significant reduction in MGMT expression, leading to intensified TMZ sensitivity in the HEK293T cell line.

CONCLUSION

This study serves as a proof of concept for the utilization of CRISPR-based gene suppression to overcome TMZ resistance and enhance the lethal effect of TMZ in glioblastoma tumor cells.

Regulatory effects of statins on Akt signaling for prevention of cancers

Statins, which are primarily used as lipid-lowering drugs, have been found to exhibit anti-tumor effects through modulating and interfering with various signaling pathways. In observational studies, statin use has been associated with a significant reduction in the progression of various cancers, including colon, lung, prostate, pancreas, and esophagus cancer, as well as melanoma and B and T cell lymphoma. The mevalonate pathway, which is affected by statins, plays a crucial role in activating Rho, Ras, and Rab proteins, thereby impacting the proliferation and apoptosis of tumor cells. Statins block this pathway, leading to the inhibition of isoprenoid units, which are critical for the activation of these key proteins, thereby affecting cancer cell behavior. Additionally, statins affect MAPK and Cdk2, which in turn reduce the expression of p21 and p27 cyclin-dependent kinase inhibitors. Akt signaling plays a crucial role in key cancer cell features like proliferation, invasion, and apoptosis by activating multiple effectors in downstream pathways such as FOXO, PTEN, NF-κB, GSK3β, and mTOR. The PI3K/Akt signaling is necessary for many events in the metastatic pathway and has been implicated in the resistance to cytostatic drugs. The Akt/PTEN axis is currently attracting great interest for its role in carcinogenesis. Statins have been shown to activate the purinergic receptor P2X7 and affect Akt signaling, which may have important anti-cancer effects. Hence, targeting Akt shows promise as an effective approach to cancer prevention and therapy. This review aims to provide a comprehensive discussion on the specific impact of statins through Akt signaling in different types of cancer.

Immunomodulatory signalling networks in glioblastoma multiforme: a comprehensive review of therapeutic approaches

Glioblastoma multiforme is a very aggressive type of cancer with high mortality and poor prognosis worldwide. Advanced treatment options with an understanding of the molecules and signalling mechanisms involved in this type of cancer have the potential to increase targeted therapy and decrease off-target effects, resistance, and recurrence. Glioblastoma multiforme (GBM) presents a complex tumour microenvironment with numerous cellular components and an extracellular matrix comprising multiple components. A deeper understanding of these components and corresponding signalling pathways can increase the success of immune checkpoint inhibitors in the treatment of GBM. The discovery of specific molecular changes and biomarkers has led to the investigation of tailored treatments for individual patients. Combination therapies targeting multiple pathways or utilizing different modalities are emerging as a promising strategy albeit with challenges in drug delivery to the brain. The review presents a comprehensive update of the various immunomodulatory signalling networks in GBM and highlights the corresponding therapeutic approaches by targeting them.

Breaking the barrier: Nanoparticle-enhanced radiotherapy as the new vanguard in brain tumor treatment

The pursuit of effective treatments for brain tumors has increasingly focused on the promising area of nanoparticle-enhanced radiotherapy (NERT). This review elucidates the context and significance of NERT, with a particular emphasis on its application in brain tumor therapy-a field where traditional treatments often encounter obstacles due to the blood-brain barrier (BBB) and tumor cells' inherent resistance. The aims of this review include synthesizing recent advancements, analyzing action mechanisms, and assessing the clinical potential and challenges associated with nanoparticle (NP) use in radiotherapy enhancement. Preliminary preclinical studies have established a foundation for NERT, demonstrating that nanoparticles (NPs) can serve as radiosensitizers, thereby intensifying radiotherapy's efficacy. Investigations into various NP types, such as metallic, magnetic, and polymeric, have each unveiled distinct interactions with ionizing radiation, leading to an augmented destruction of tumor cells. These interactions, encompassing physical dose enhancement and biological and chemical radio sensitization, are crucial to the NERT strategy. Although clinical studies are in their early phases, initial trials have shown promising results in terms of tumor response rates and survival, albeit with mindful consideration of toxicity profiles. This review examines pivotal studies affirming NERT's efficacy and safety. NPs have the potential to revolutionize radiotherapy by overcoming challenges in targeted delivery, reducing off-target effects, and harmonizing with other modalities. Future directions include refining NP formulations, personalizing therapies, and navigating regulatory pathways. NERT holds promise to transform brain tumor treatment and provide hope for patients.

Potential mechanisms of cancer prevention and treatment by sulforaphane, a natural small molecule compound of plant-derived

Despite recent advances in tumor diagnosis and treatment technologies, the number of cancer cases and deaths worldwide continues to increase yearly, creating an urgent need to find new methods to prevent or treat cancer. Sulforaphane (SFN), as a member of the isothiocyanates (ITCs) family, which is the hydrolysis product of glucosinolates (GLs), has been shown to have significant preventive and therapeutic cancer effects in different human cancers. Early studies have shown that SFN scavenges oxygen radicals by increasing cellular defenses against oxidative damage, mainly through the induction of phase II detoxification enzymes by nuclear factor erythroid 2-related factor 2 (Nrf2). More and more studies have shown that the anticancer mechanism of SFN also includes induction of apoptotic pathway in tumor cells, inhibition of cell cycle progression, and suppression of tumor stem cells. Therefore, the application of SFN is expected to be a necessary new approach to treating cancer. In this paper, we review the multiple molecular mechanisms of SFN in cancer prevention and treatment in recent years, which can provide a new vision for cancer treatment.

Role of microRNAs in tumor progression by regulation of kinesin motor proteins

Aberrant cell proliferation is one of the main characteristics of tumor cells that can be affected by many cellular processes and signaling pathways. Kinesin superfamily proteins (KIFs) are motor proteins that are involved in cytoplasmic transportations and chromosomal segregation during cell proliferation. Therefore, regulation of the KIF functions as vital factors in chromosomal stability is necessary to maintain normal cellular homeostasis and proliferation. KIF deregulations have been reported in various cancers. MicroRNAs (miRNAs) and signaling pathways are important regulators of KIF proteins. MiRNAs have key roles in regulation of the cell proliferation, migration, and apoptosis. In the present review, we discussed the role of miRNAs in tumor biology through the regulation of KIF proteins. It has been shown that miRNAs have mainly a tumor suppressor function via the KIF targeting. This review can be an effective step to introduce the miRNAs/KIFs axis as a probable therapeutic target in tumor cells.

MCM5 is a Novel Therapeutic Target for Glioblastoma

Objective

MCM5 is a DNA licensing factor involved in cell proliferation and has been previously established as an excellent biomarker in a number of malignancies. Nevertheless, the role of MCM5 in GBM has not been fully clarified. The present study aimed to investigate the potential roles of MCM5 in the treatment of GBM and to elucidate its underlying mechanism, which is beneficial for developing new therapeutic strategies and predicting prognosis.

Methods

Firstly, we obtained transcriptomic and proteomic data from the TCGA and CPTAC databases on glioma patients. Employing the DeSeq2 R package, we then identified genes with joint differential expression in GBM tissues subjected to chemotherapy. To develop a prognostic risk score model, we performed univariate and multivariate Cox regression analyses. In vitro knockdown and overexpression of MCM5 were used to further investigate the biological functions of GBM cells. Additionally, we also delved into the upstream regulation of MCM5, revealing associations with several transcription factors. Finally, we investigated differences in immune cell infiltration and drug sensitivity across diverse risk groups identified in the prognostic risk model.

Results

In this study, the chemotherapy-treated GBM samples exhibited consistent alterations in 46 upregulated and 94 downregulated genes at both the mRNA and protein levels. Notably, MCM5 emerged as a gene with prognostic significance as well as potential therapeutic relevance. In vitro experiments subsequently validated the role of increased MCM5 expression in promoting GBM cell proliferation and resistance to TMZ. Correlations with transcription factors such as CREB1, CTCF, NFYB, NRF1, PBX1, TEAD1, and USF1 were discovered during upstream regulatory analysis, enriching our understanding of MCM5 regulatory mechanisms. The study additionally delves into immune cell infiltration and drug sensitivity, providing valuable insights for personalized treatment approaches.

Conclusion

This study identifies MCM5 as a key player in GBM, demonstrating its prognostic significance and potential therapeutic relevance by elucidating its role in promoting cell proliferation and resistance to chemotherapy.

Hypoxia-induced galectin-8 maintains stemness in glioma stem cells via autophagy regulation

BACKGROUND

Glioma stem cells (GSCs) are the root cause of relapse and treatment resistance in glioblastoma (GBM). In GSCs, hypoxia in the microenvironment is known to facilitate the maintenance of stem cells, and evolutionally conserved autophagy regulates cell homeostasis to control cell population. The precise involvement of autophagy regulation in hypoxic conditions in maintaining the stemness of GSCs remains unclear.

METHODS

The association of autophagy regulation and hypoxia was first assessed by in silico analysis and validation in vitro. Glioma databases and clinical specimens were used to determine galectin-8 (Gal-8) expression in GSCs and human GBMs, and the regulation and function of Gal-8 in stemness maintenance were evaluated by genetic manipulation in vitro and in vivo. How autophagy was stimulated by Gal-8 under hypoxia was systematically investigated.

RESULTS

Hypoxia enhances autophagy in GSCs to facilitate self-renewal, and Gal-8 in the galectin family is specifically involved and expressed in GSCs within the hypoxic niche. Gal-8 is highly expressed in GBM and predicts poor survival in patients. Suppression of Gal-8 prevents tumor growth and prolongs survival in mouse models of GBM. Gal-8 binds to the Ragulator-Rag complex at the lysosome membrane and inactivates mTORC1, leading to the nuclear translocation of downstream TFEB and initiation of autophagic lysosomal biogenesis. Consequently, the survival and proliferative activity of GSCs are maintained.

CONCLUSIONS

Our findings reveal a novel Gal-8-mTOR-TFEB axis induced by hypoxia in the maintenance of GSC stemness via autophagy reinforcement, highlighting Gal-8 as a candidate for GSCs-targeted GBM therapy.

Daurisoline suppress glioma progression by inhibiting autophagy through PI3K/AKT/mTOR pathway and increases TMZ sensitivity

Glioma is one of the most common primary malignant tumors of the central nervous system. Temozolomide (TMZ) is the only effective chemotherapeutic agent, but it easily develops resistance and has unsatisfactory efficacy. Consequently, there is an urgent need to develop safe and effective compounds for glioma treatment. The cytotoxicity of 30 candidate compounds to glioma cells was detected by the CCK-8 assay. Daurisoline (DAS) was selected for further investigation due to its potent anti-glioma effects. Our study revealed that DAS induced glioma cell apoptosis through increasing caspase-3/6/9 activity. DAS significantly inhibited the proliferation of glioma cells by inducing G1-phase cell cycle arrest. Meanwhile, DAS remarkably suppressed the migration and invasion of glioma cells by regulating epithelial-mesenchymal transition. Mechanistically, our results revealed that DAS impaired the autophagic flux of glioma cells at a late stage by mediating the PI3K/AKT/mTOR pathway. DAS could inhibit TMZ-induced autophagy and then significantly promote TMZ chemosensitivity. Nude mice xenograft model revealed that DAS could restrain glioma proliferation and promote TMZ chemosensitivity. Thus, DAS is a potential anti-glioma drug that can improve glioma sensitivity to TMZ and provide a new therapeutic strategy for glioma in chemoresistance.

Regorafenib and glioblastoma: a literature review of preclinical studies, molecular mechanisms and clinical effectiveness

Glioblastoma IDH wild type (GBM) is a very aggressive brain tumour, characterised by an infiltrative growth pattern and by a prominent neoangiogenesis. Its prognosis is unfortunately dismal, and the median overall survival of GBM patients is short (15 months). Clinical management is based on bulk tumour removal and standard chemoradiation with the alkylating drug temozolomide, but the tumour invariably recurs leading to patient's death. Clinical options for GBM patients remained unaltered for almost two decades until the encouraging results obtained by the phase II REGOMA trial allowed the introduction of the multikinase inhibitor regorafenib as a preferred regimen in relapsed GBM treatment by the National Comprehensive Cancer Network (NCCN) 2020 Guideline. Regorafenib, a sorafenib derivative, targets kinases associated with angiogenesis (VEGFR 1-3), as well as oncogenesis (c-KIT, RET, FGFR) and stromal kinases (FGFR, PDGFR-b). It was already approved for metastatic colorectal cancers and hepatocellular carcinomas. The aim of the present review is to focus on both the molecular and clinical knowledge collected in these first three years of regorafenib use in GBM.

Role of NuMA1 in breast cancer stem cells with implications for combination therapy of PIM1 and autophagy inhibition in triple negative breast cancer

Background

Nuclear mitotic apparatus protein 1 (NuMA1) is a cell cycle protein and upregulated in breast cancer. However, the role of NuMA1 in TNBC and its regulation in heterogenous populations remains elusive.

Methods

We performed CRISPR mediated deletion of NuMA1 in mouse TNBC cells, BF3M. FACS was utilized to isolate BCSCs, and bulk cells based on CD29 and CD61 markers. Cell viability, migration, and invasion ability of BCSCs and bulk cells was evaluated using MTT, wound healing and transwell invasion assays, respectively. In vivo mouse breast cancer and lung metastatic models were generated to evaluate the combination treatment of SMI-4a and Lys-o5 inhibitors.

Results

We identified that high expression of NuMA1 associated with poor survival of breast cancer patients. Further, human tissue microarray results depicted high expression of NuMA1 in TNBC relative to non-adjacent normal tissues. Therefore, we performed CRISPR mediated deletion of NuMA1 in a mouse mammary tumor cell line, BF3M and revealed that NuMA1 deletion reduced mammary tumorigenesis. We also showed that NuMA1 deletion reduced ALDH+ and CD29hiCD61+ breast cancer stem cells (BCSCs), indicating a role of NuMA1 in BCSCs. Further, sorted and characterized BCSCs from BF3M depicted reduced metastasis with NuMA1 KO cells. Moreover, we found that PIM1, an upstream kinase of NuMA1 plays a preferential role in maintenance of BCSCs associated phenotypes, but not in bulk cells. In contrast, PIM1 kinase inhibition in bulk cells depicted increased autophagy (FIP200). Therefore, we applied a combination treatment strategy of PIM1 and autophagy inhibition using SMI-4a and Lys05 respectively, showed higher efficacy against cell viability of both these populations and further reduced breast tumor formation and metastasis. Together, our study demonstrated NuMA1 as a potential therapeutic target and combination treatment using inhibitors for an upstream kinase PIM1 and autophagy inhibitors could be a potentially new therapeutic approach for TNBC.

Conclusions

Our study demonstrated that combination treatment of PIM1 inhibitor and autophagy inhibitor depicted reduced mammary tumorigenesis and metastasis by targeting NuMA1 in BCSCs and bulk cells of TNBC, demonstrating this combination treatment approach could be a potentially effective therapy for TNBC patients.

Design, synthesis and biological evaluation of Nrf2 modulators for the treatment of glioblastoma multiforme

Glioblastoma multiforme (GBM) is a prevalent primary brain tumor. However, no specific therapeutic drug has been developed for it. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a crucial transcription factor involved in the cellular response to oxidative stress. Numerous studies have demonstrated that Nrf2 plays a pivotal role in GBM angiogenesis, and inhibiting Nrf2 can significantly enhance patient prognosis. Using virtual screening technology, we examined our in-house library and identified pinosylvin as a potential compound with high activity. Pinosylvin exhibited robust hydrogen bond and Π-Π interaction with Nrf2. Cell experiments revealed that pinosylvin effectively reduced the proliferation of U87 tumor cells by regulating Nrf2 and demonstrated greater inhibitory activity than temozolomide. Consequently, we believe that this study will offer valuable guidance for the future development of highly efficient therapeutic drugs for GBM.

Epigenetic Reprogramming of Autophagy Drives Mutant IDH1 Glioma Progression and Response to Radiation

Mutant isocitrate dehydrogenase 1 (mIDH1; IDH1 R132H ) exhibits a gain of function mutation enabling 2-hydroxyglutarate (2HG) production. 2HG inhibits DNA and histone demethylases, inducing epigenetic reprogramming and corresponding changes to the transcriptome. We previously demonstrated 2HG-mediated epigenetic reprogramming enhances DNA-damage response and confers radioresistance in mIDH1 gliomas harboring p53 and ATRX loss of function mutations. In this study, RNA-seq and ChIP-seq data revealed human and mouse mIDH1 glioma neurospheres have downregulated gene ontologies related to mitochondrial metabolism and upregulated autophagy. Further analysis revealed that the decreased mitochondrial metabolism was paralleled by a decrease in glycolysis, rendering autophagy as a source of energy in mIDH1 glioma cells. Analysis of autophagy pathways showed that mIDH1 glioma cells exhibited increased expression of pULK1-S555 and enhanced LC3 I/II conversion, indicating augmented autophagy activity. This dependence is reflected by increased sensitivity of mIDH1 glioma cells to autophagy inhibition. Blocking autophagy selectively impairs the growth of cultured mIDH1 glioma cells but not wild-type IDH1 (wtIDH1) glioma cells. Targeting autophagy by systemic administration of synthetic protein nanoparticles packaged with siRNA targeting Atg7 (SPNP-siRNA-Atg7) sensitized mIDH1 glioma cells to radiation-induced cell death, resulting in tumor regression, long-term survival, and immunological memory, when used in combination with IR. Our results indicate autophagy as a critical pathway for survival and maintenance of mIDH1 glioma cells, a strategy that has significant potential for future clinical translation.

One Sentence Summary

The inhibition of autophagy sensitizes mIDH1 glioma cells to radiation, thus creating a promising therapeutic strategy for mIDH1 glioma patients.

Graphical abstract

Our genetically engineered mIDH1 mouse glioma model harbors IDH1 R132H in the context of ATRX and TP53 knockdown. The production of 2-HG elicited an epigenetic reprogramming associated with a disruption in mitochondrial activity and an enhancement of autophagy in mIDH1 glioma cells. Autophagy is a mechanism involved in cell homeostasis related with cell survival under energetic stress and DNA damage protection. Autophagy has been associated with radio resistance. The inhibition of autophagy thus radio sensitizes mIDH1 glioma cells and enhances survival of mIDH1 glioma-bearing mice, representing a novel therapeutic target for this glioma subtype with potential applicability in combined clinical strategies.

IGF2BP2 modulates autophagy and serves as a prognostic marker in glioma

Glioma, a malignant brain tumor originating from neural glial cells, presents significant treatment challenges. However, the underlying mechanisms of glioma development are not fully understood, and effective targets are lacking. This study provides insights into the role of insulin-like growth factor 2 messenger RNA-binding protein 2 (IGF2BP2) in glioma progression and its therapeutic potential. Our analysis illustrated that elevated IGF2BP2 expression associated with significantly shorter survival among patients with low-grade glioma (LGG) in The Cancer Genome Atlas (TCGA) database. IGF2BP2 depletion led to compromised cell viability, G0/G1 phase arrest, and reduced colony-formation ability. Furthermore, ultrastructural analysis and mCherry-GFP-LC3 reporter assay revealed an increased abundance of autophagosomes upon IGF2BP2 knockdown. Western blot analysis corroborated these findings by showing reduced p62 levels coupled with increased LC3-ІІ/LC3-I ratio upon IGF2BP2 knockdown. A multicolor immunohistochemistry assay demonstrated the positive correlation between IGF2BP2 and p62 expression in glioma patient samples. Additionally, our analysis suggested a link between IGF2BP2 expression and drug-resistant markers in TCGA-LGG samples, and Cell Counting Kit-8 cell viability assay revealed that knockdown of IGF2BP2 sensitized cells to temozolomide treatment. This comprehensive exploration unveils the role of IGF2BP2 in glioma progression, shedding light on autophagy modulation and chemosensitization strategies for glioma therapy.

SMG9 is a novel prognostic-related biomarker in glioma correlating with ferroptosis and immune infiltrates

Background

Glioma is the most frequent type of malignancy that may damage the brain with high morbidity and mortality rates and patients' prognoses are still dismal. Ferroptosis, a newly uncovered mode of programmed cell death, may be triggered to destroy glioma cells. Nevertheless, the significance of ferroptosis-related genes (FRGs) in predicting prognosis in glioma individuals is still a mystery.

Methods

The CGGA (The Chinese Glioma Atlas), GEO (Gene Expression Omnibus), and TCGA (The Cancer Genome Atlas) databases were all searched to obtain the glioma expression dataset. First, TCGA was searched to identify differentially expressed genes (DEGs). This was followed by a machine learning algorithm-based screening of the glioma's most relevant genes. Additionally, these genes were subjected to Gene Ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) functional enrichment analyses. The chosen biological markers were then submitted to single-cell, immune function, and gene set enrichment analysis (GSEA). In addition, we performed functional enrichment and Mfuzz expression profile clustering on the most promising biological markers to delve deeper into their regulatory mechanisms and assess their clinical diagnostic capacities.

Results

We identified 4444 DEGs via differential analysis and 564 FRGs from the FerrDb database. The two were subjected to intersection analysis, which led to the discovery of 143 overlapping genes. After that, glioma biological markers were identified in fourteen genes by the use of machine learning methods. In terms of its use for clinical diagnosis, SMG9 stands out as the most significant among these biomarkers.

Conclusion

In light of these findings, the identification of SMG9 as a new biological marker has the potential to provide information on the mechanism of action and the effect of the immune milieu in glioma. The promise of SMG9 in glioma prognosis prediction warrants more study.

Valproic acid regulates the miR-155/Jarid2 axis by affecting miR-155 promoter methylation in glioma

The most frequent primary brain tumor in adults is glioma, yet no effective curative treatments are currently available. Our previous study demonstrated the enhancing effects of JARID2 on glioma sensitivity to TMZ treatment. In this study, miR-155 is predicted to target JARID2. miR-155 is overexpressed in clinical glioma specimens and cell lines. miR-155 overexpression in glioma cells enhances cell viability and represses cell apoptosis. Through targeting, miR-155 inhibits JARID2 expression. miR-155 inhibition inhibits glioma cell viability and enhances cell apoptosis, whereas JARID2 knockdown enhances cell viability and inhibits cell apoptosis; JARID2 knockdown partially reverses miR-155 inhibition effects on glioma phenotypes. miR-155 inhibition reduces but knockdown of JARID2 promotes the tumor formation ability of glioma cells in vivo. Valproic acid (VPA) upregulates JARID2 expression, inhibits glioma cell viability and enhances cell apoptosis. VPA downregulates the expression level of miR-155 by increasing the methylation level of the miR-155 promoter, suggesting that the miR-155/JARID2 axis is implicated in VPA inhibition of glioma cell viability and enhancement of glioma cell apoptosis. This study demonstrates a new mechanism of VPA treatment of gliomas by affecting the miR-155/JARID2 axis, which could be regarded as a new strategy for the prevention and treatment of glioma.

Synthesis and Structural Optimization of ATG4B Inhibitors for the Attenuation of Autophagy in Glioblastoma

Glioblastoma, a prevalent malignant CNS tumor, presents a therapeutic challenge because of resistance to standard treatments, including radiation therapy and temozolomide. Both modalities induce autophagy, thereby paradoxically promoting tumor survival. The cysteine protease ATG4B is implicated in this cellular process, which highlights the enzyme as a viable therapeutic target for glioblastoma. We have developed streamlined syntheses for ATG4B inhibitor NSC185058, its derivatives, and fluorogenic ATG4B substrate pim-FG-PABA-AMC. We leveraged these findings to rapidly identify novel compound MJO445, which demonstrates markedly greater potency biochemically and in cells.

Caveolin-1 promotes glioma proliferation and metastasis by enhancing EMT via mediating PAI-1 activation and its correlation with immune infiltrates

Glioma is typically characterized by a poor prognosis and is associated with a decline in the quality of life as the disease advances. However, the development of effective therapies for glioma has been inadequate. Caveolin-1 (CAV-1) is a membrane protein that plays a role in caveolae formation and interacts with numerous signaling proteins, compartmentalizing them in caveolae and frequently exerting direct control over their activity through binding to its scaffolding domain. Although CAV-1 is a vital regulator of tumour progression, its role in glioma remains unclear. Our findings indicated that the knockdown of CAV-1 significantly inhibits the proliferation and metastasis of glioma. Subsequent mechanistic investigations demonstrated that CAV-1 promotes proliferation and metastasis by activating the photoshatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway. Furthermore, we demonstrated that CAV-1 overexpression upregulates the expression of serpin peptidase inhibitor, class E, member 1 (SERPINE1, also known as PAI-1), which serves as a marker for the epithelial-mesenchymal transition (EMT) process. Further research showed that PAI-1 knockdown abolished the CAV-1 mediated activation of PI3K/Akt signaling pathway. In glioma tissues, CAV-1 expression exhibited a correlation with unfavorable prognosis and immune infiltration among glioma patients. In summary, our study provided evidence that CAV-1 activates the PI3K/Akt signaling pathway by upregulating PAI-1, thereby promoting the proliferation and metastasis of glioma through enhanced epithelial-mesenchymal transition (EMT) and angiogenesis, and CAV-1 is involved in the immune infiltration.

Targeted Mevalonate Pathway and Autophagy in Antitumor Immunotherapy

Tumors of the digestive system are currently one of the leading causes of cancer-related death worldwide. Despite considerable progress in tumor immunotherapy, the prognosis for most patients remains poor. In the tumor microenvironment (TME), tumor cells attain immune escape through immune editing and acquire immune tolerance. The mevalonate pathway and autophagy play important roles in cancer biology, antitumor immunity, and regulation of the TME. In addition, there is metabolic crosstalk between the two pathways. However, their role in promoting immune tolerance in digestive system tumors has not previously been summarized. Therefore, this review focuses on the cancer biology of the mevalonate pathway and autophagy, the regulation of the TME, metabolic crosstalk between the pathways, and the evaluation of their efficacy as targeted inhibitors in clinical tumor immunotherapy.

CPT1A mediates chemoresistance in human hypopharyngeal squamous cell carcinoma via ATG16L1-dependent cellular autophagy

Hypopharyngeal squamous cell carcinoma (HSCC) is a highly aggressive malignancy that constitutes approximately 95% of all hypopharyngeal carcinomas, and it carries a poor prognosis. The primary factor influencing the efficacy of anti-cancer drugs for this type of carcinoma is chemoresistance. Carnitine palmitoyltransferase 1A (CPT1A) has been associated with tumor progression in various cancers, including breast, gastric, lung, and prostate cancer. The inhibition or depletion of CPT1A can lead to apoptosis, curbing cancer cell proliferation and chemoresistance. However, the role of CPT1A in HSCC is not yet fully understood. In this study, we discovered that CPT1A is highly expressed in HSCC and is associated with an advanced T-stage and a poor 5-year survival rate among patients. Furthermore, the overexpression of CPT1A contributes to HSCC chemoresistance. Mechanistically, CPT1A can interact with the autophagy-related protein ATG16L1 and stimulate the succinylation of ATG16L1, which in turn drives autophagosome formation and autophagy. We also found that treatment with 3-methyladenine (3-MA) can reduce cisplatin resistance in HSCC cells that overexpress CPT1A. Our findings also showed that a CPT1A inhibitor significantly enhances cisplatin sensitivity both in vitro and in vivo. This study is the first to suggest that CPT1A has a regulatory role in autophagy and is linked to poor prognosis in HSCC patients. It presents novel insights into the roles of CPT1A in tumorigenesis and proposes that CPT1A could be a potential therapeutic target for HSCC treatment.

Recent advances in drug delivery systems for targeting brain tumors

Brain tumor accounts for about 1.6% of incidence and 2.5% of mortality of all tumors, and the median survival for brain tumor patients is only about 20 months. The treatment for brain tumor still faces many challenges, such as the blood-brain barrier (BBB), blood-brain tumor barrier (BBTB), the overexpressed efflux pumps, the infiltration, invasion, high heterogeneity of tumor cells, drug resistance and immune escape caused by tumor microenvironment (TME) and cancer stem cells (CSC). This review attempts to clarify the challenges for multi-functional nano drug delivery systems (NDDS) to cross the BBB and target the cancer cells or organelles, and also provides a brief description of the different types of targeted multi-functional NDDS that have shown potential for success in delivering drugs to the brain. Further, this review also summarizes the research progress of multi-functional NDDS in the combination therapy of brain tumors from the following sections, the combination of chemotherapy drugs, chemotherapy-chemodynamic combination therapy, chemotherapy-immunization combination therapy, and chemotherapy-gene combination therapy. We also provide an insight into the recent advances in designing multi-functional NDDS for combination therapy.

Molecular Targeted Therapies in Glioblastoma Multiforme: A Systematic Overview of Global Trends and Findings

This systematic review assesses current molecular targeted therapies for glioblastoma multiforme (GBM), a challenging condition with limited treatment options. Using PRISMA methodology, 166 eligible studies, involving 2526 patients (61.49% male, 38.51% female, with a male-to-female ratio of 1.59/1), were analyzed. In laboratory studies, 52.52% primarily used human glioblastoma cell cultures (HCC), and 43.17% employed animal samples (mainly mice). Clinical participants ranged from 18 to 100 years, with 60.2% using combined therapies and 39.8% monotherapies. Mechanistic categories included Protein Kinase Phosphorylation (41.6%), Cell Cycle-Related Mechanisms (18.1%), Microenvironmental Targets (19.9%), Immunological Targets (4.2%), and Other Mechanisms (16.3%). Key molecular targets included Epidermal Growth Factor Receptor (EGFR) (10.8%), Mammalian Target of Rapamycin (mTOR) (7.2%), Vascular Endothelial Growth Factor (VEGF) (6.6%), and Mitogen-Activated Protein Kinase (MEK) (5.4%). This review provides a comprehensive assessment of molecular therapies for GBM, highlighting their varied efficacy in clinical and laboratory settings, ultimately impacting overall and progression-free survival in GBM management.

Molecular mechanisms of resveratrol as chemo and radiosensitizer in cancer

One of the primary diseases that cause death worldwide is cancer. Cancer cells can be intrinsically resistant or acquire resistance to therapies and drugs used for cancer treatment through multiple mechanisms of action that favor cell survival and proliferation, becoming one of the leading causes of treatment failure against cancer. A promising strategy to overcome chemoresistance and radioresistance is the co-administration of anticancer agents and natural compounds with anticancer properties, such as the polyphenolic compound resveratrol (RSV). RSV has been reported to be able to sensitize cancer cells to chemotherapeutic agents and radiotherapy, promoting cancer cell death. This review describes the reported molecular mechanisms by which RSV sensitizes tumor cells to radiotherapy and chemotherapy treatment.

Ion channels and their role in chemo-resistance

Ion channels play a crucial role in cellular signaling, homeostasis, and generation of electrical and chemical signals. Aberrant expression and dysregulation of ion channels have been associated with cancer development and resistance to conventional cancer treatment such as chemotherapy. Several molecular mechanisms have been proposed to explain this phenomenon. Including evasion of apoptosis, decreased drug accumulation in cancer cells, detoxifying and activation of alternative escape pathways such as autophagy. Each of these mechanisms leads to a reduction of the therapeutic efficacy of administered drugs, causing more difficulty in cancer treatment. This review highlights the linkages between ion channels and resistance to chemotherapy. Furthermore, it elaborates their molecular mechanisms and the potential of being therapeutic targets in clinical management.

FKBP38 Regulates Self-Renewal and Survival of GBM Neurospheres

Glioblastoma is the most common malignant primary brain tumor. The outcome is dismal, despite the multimodal therapeutic approach that includes surgical resection, followed by radiation and chemotherapy. The quest for novel therapeutic targets to treat glioblastoma is underway. FKBP38, a member of the immunophilin family of proteins, is a multidomain protein that plays an important role in the regulation of cellular functions, including apoptosis and autophagy. In this study, we tested the role of FKBP38 in glioblastoma tumor biology. Expression of FKBP38 was upregulated in the patient-derived primary glioblastoma neurospheres (GBMNS), compared to normal human astrocytes. Attenuation of FKBP38 expression decreased the viability of GBMNSs and increased the caspase 3/7 activity, indicating that FKBP38 is required for the survival of GBMNSs. Further, the depletion of FKBP38 significantly reduced the number of neurospheres that were formed, implying that FKBP38 regulates the self-renewal of GBMNSs. Additionally, the transient knockdown of FKBP38 increased the LC3-II/I ratio, suggesting the induction of autophagy with the depletion of FKBP38. Further investigation showed that the negative regulation of autophagy by FKBP38 in GBMNSs is mediated through the JNK/C-Jun-PTEN-AKT pathway. In vivo, FKBP38 depletion significantly extended the survival of tumor-bearing mice. Overall, our results suggest that targeting FKBP38 imparts an anti-glioblastoma effect by inducing apoptosis and autophagy and thus can be a potential therapeutic target for glioblastoma therapy.

H1Innovative approaches to combat anti-cancer drug resistance: Targeting lncRNA and autophagy

BACKGROUND

To date, standardizing clinical predictive biomarkers for assessing the response to immunotherapy remains challenging due to variations in personal genetic signatures, tumour microenvironment complexities and epigenetic onco-mechanisms.

MAIN BODY

Early monitoring of key non-coding RNA (ncRNA) biomarkers may help in predicting the clinical efficacy of cancer immunotherapy and come up with standard predictive ncRNA biomarkers. For instance, reduced miR-125b-5p level in the plasma of non-small cell lung cancer patients treated with anti-PD-1 predicts a positive outcome. The level of miR-153 in the plasma of colorectal cancer patients treated with chimeric antigen receptor T lymphocyte (CAR-T) cell therapy may indicate the activation of T-cell killing activity. miR-148a-3p and miR-375 levels may forecast favourable responses to CAR-T-cell therapy in B-cell acute lymphoblastic leukaemia. In cancer patients treated with the GPC3 peptide vaccine, serum levels of miR-1228-5p, miR-193a-5p and miR-375-3p were reported as predictive biomarkers of good response and improved overall survival. Therefore, there is a critical need for further studies to elaborate on the key ncRNA biomarkers that have the potential to predict early clinical responses to immunotherapy.

CONCLUSIONS

This review summarises important predictive ncRNA biomarkers that were reported in cancer patients treated with different immunotherapeutic modalities including monoclonal antibodies, small molecule inhibitors, cancer vaccines and CAR-T cells. In addition, a concise discussion on forthcoming perspectives is provided, outlining technical approaches for the optimal utilisation of immune-modulatory ncRNA biomarkers as predictive tools and therapeutic targets.

Autophagy in combination therapy of temozolomide and IFN-γ in C6-induced glioblastoma: role of non-coding RNAs

Aim: We predicted the modulation of autophagy and apoptosis in response to temozolomide (TMZ) and IFN-γ based on changes in the expression of non-coding RNAs in C6-induced glioblastoma (GBM). Materials & methods: Each rat received an intraperitoneal injection of TMZ (7.5 mg/kg) and/or IFN-γ (50,000 IU). Results: The reduced expression of H19 and colorectal neoplasia differentially expressed (CRNDE) was associated with a reduction in autophagy in response to TMZ, IFN-γ and TMZ + IFN-γ therapy, whereas the decreased level of miR-29a (proapoptotic miRNA) was associated with an increase in apoptosis. Conclusion: It appears that H19 promotes switching from autophagy to apoptosis in response to combination therapy of TMZ and IFN-γ through the miR-29a/autophagy-related protein 9A (ATG9A) pathway in C6-induced GBM.

Autophagy Inhibition with Chloroquine Increased Pro-Apoptotic Potential of New Aziridine-Hydrazide Hydrazone Derivatives against Glioblastoma Cells

Tumor therapy escape due to undesired side effects induced by treatment, such as prosurvival autophagy or cellular senescence, is one of the key mechanisms of resistance that eventually leads to tumor dormancy and recurrence. Glioblastoma is the most frequent and practically incurable neoplasm of the central nervous system; thus, new treatment modalities have been investigated to find a solution more effective than the currently applied standards based on temozolomide. The present study examined the newly synthesized compounds of aziridine-hydrazide hydrazone derivatives to determine their antineoplastic potential against glioblastoma cells in vitro. Although the output of our investigation clearly demonstrates their proapoptotic activity, the cytotoxic effect appeared to be blocked by treatment-induced autophagy, the phenomenon also detected in the case of temozolomide action. The addition of an autophagy inhibitor, chloroquine, resulted in a significant increase in apoptosis triggered by the tested compounds, as well as temozolomide. The new aziridine-hydrazide hydrazone derivatives, which present cytotoxic potential against glioblastoma cells comparable to or even higher than that of temozolomide, show promising results and, thus, should be further investigated as antineoplastic agents. Moreover, our findings suggest that the combination of an apoptosis inducer with an autophagy inhibitor could optimize chemotherapeutic efficiency, and the addition of an autophagy inhibitor should be considered as an optional adjunctive therapy minimizing the risk of tumor escape from treatment.

Exosomal circRNAs in cancer: Implications for therapy resistance and biomarkers

Despite the advances in cancer treatment in recent years, the development of resistance to cancer therapy remains the biggest hurdle towards curative cancer treatments. Therefore, investigating the molecular mechanisms underlying cancer therapy resistance is of paramount clinical importance. Circular RNAs (circRNAs), novel members of the noncoding RNA family, are endogenous biomolecules in eukaryotes characterized by a covalently closed loop structure with multiple biological functions. Significantly, circRNAs are abundant and stable in exosomes and can be packaged, secreted and transferred to targeted tumour cells, thereby modulating diverse hallmarks of cancer behaviours, such as proliferation, migration, and immune escape. Notably, a great number of exosomal circRNAs are abnormally expressed during cancer treatment and can mediate cancer therapy resistance through complex mechanisms; therefore, targeting exosomal circRNAs is a promising therapeutic method to reverse therapy resistance. This review aimed to elucidate the mechanisms underlying exosomal circRNAs controlling the resistance of cancer to common therapies, such as chemotherapy, targeted therapy, immunotherapy and radiotherapy, and we also discussed the therapeutic potential of exosomal circRNAs as clinical biomarkers and novel targets in cancer clinical management. We also discussed the prospects and challenges of targeting exosomal circRNAs as a novel therapeutic strategy for reversing cancer therapy resistance.

SDC1-TGM2-FLOT1-BHMT complex determines radiosensitivity of glioblastoma by influencing the fusion of autophagosomes with lysosomes

Rationale: Glioblastoma (GBM) is the most common and malignant primary brain tumor in adults. Radiotherapy has long been an important treatment for GBM. Despite recent advances in tumor radiotherapy, the prognosis of GBM remains poor due to radioresistance. Autophagy has been reported as a basic factor to prolong the survival of tumor under radiation stress, but the molecular mechanism of how autophagy contributes to GBM radioresistance was still lacking. Methods: We established radioresistant GBM cells and identified their protein profiles by Tandem mass tag (TMT) quantitative proteomic analysis, then chose the radioresistant genes based on the TMT analysis of GBM cells and differentially expressed genes (DEGs) analysis of GEO database. Colony formation, flow cytometry, qPCR, western blotting, mRFP-GFP-LC3, transmission electron microscopy, immunofluorescence, and co-IP assays were conducted to investigate the regulation mechanisms among these new-found molecules. Results: Syndecan 1 (SDC1) and Transglutaminase 2 (TGM2) were both overexpressed in the radioresistant GBM cells and tissues, contributing to the dismal prognosis of radiotherapy. Mechanically, after irradiation, SDC1 carried TGM2 from cell membrane into cytoplasm, and transported to lysosomes by binding to flotillin 1 (FLOT1), then TGM2 recognized the betaine homocysteine methyltransferase (BHMT) on autophagosomes to coordinate the encounter between autophagosomes and lysosomes. Conclusions: The SDC1-TGM2-FLOT1-BHMT copolymer, a novel member of the protein complexes involved in the fusion of lysosomes and autophagosomes, maintained the autophagic flux in the irradiated tumor cells and ultimately enhanced radioresistance of GBM, which provides new insights of the molecular mechanism and therapeutic targets of radioresistant GBM.

Sequential Treatment with Temozolomide Plus Naturally Derived AT101 as an Alternative Therapeutic Strategy: Insights into Chemoresistance Mechanisms of Surviving Glioblastoma Cells

Glioblastoma (GBM) is a poorly treatable disease due to the fast development of tumor recurrences and high resistance to chemo- and radiotherapy. To overcome the highly adaptive behavior of GBMs, especially multimodal therapeutic approaches also including natural adjuvants have been investigated. However, despite increased efficiency, some GBM cells are still able to survive these advanced treatment regimens. Given this, the present study evaluates representative chemoresistance mechanisms of surviving human GBM primary cells in a complex in vitro co-culture model upon sequential application of temozolomide (TMZ) combined with AT101, the R(-) enantiomer of the naturally occurring cottonseed-derived gossypol. Treatment with TMZ+AT101/AT101, although highly efficient, yielded a predominance of phosphatidylserine-positive GBM cells over time. Analysis of the intracellular effects revealed phosphorylation of AKT, mTOR, and GSK3ß, resulting in the induction of various pro-tumorigenic genes in surviving GBM cells. A Torin2-mediated mTOR inhibition combined with TMZ+AT101/AT101 partly counteracted the observed TMZ+AT101/AT101-associated effects. Interestingly, treatment with TMZ+AT101/AT101 concomitantly changed the amount and composition of extracellular vesicles released from surviving GBM cells. Taken together, our analyses revealed that even when chemotherapeutic agents with different effector mechanisms are combined, a variety of chemoresistance mechanisms of surviving GBM cells must be taken into account.

Pyroptosis, ferroptosis, and autophagy cross-talk in glioblastoma opens up new avenues for glioblastoma treatment

Glioma is a common primary tumor of the central nervous system (CNS), with glioblastoma multiforme (GBM) being the most malignant, aggressive, and drug resistant. Most drugs are designed to induce cancer cell death, either directly or indirectly, but malignant tumor cells can always evade death and continue to proliferate, resulting in a poor prognosis for patients. This reflects our limited understanding of the complex regulatory network that cancer cells utilize to avoid death. In addition to classical apoptosis, pyroptosis, ferroptosis, and autophagy are recognized as key cell death modalities that play significant roles in tumor progression. Various inducers or inhibitors have been discovered to target the related molecules in these pathways, and some of them have already been translated into clinical treatment. In this review, we summarized recent advances in the molecular mechanisms of inducing or inhibiting pyroptosis, ferroptosis, or autophagy in GBM, which are important for treatment or drug tolerance. We also discussed their links with apoptosis to better understand the mutual regulatory network among different cell death processes. Video Abstract.

Lnc-ing epigenetic mechanisms with autophagy and cancer drug resistance

Long noncoding RNAs (lncRNAs) comprise a diverse class of RNA molecules that regulate various physiological processes and have been reported to be involved in several human pathologies ranging from neurodegenerative disease to cancer. Therapeutic resistance is a major hurdle for cancer treatment. Over the past decade, several studies has emerged on the role of lncRNAs in cancer drug resistance and many trials have been conducted employing them. LncRNAs also regulate different cell death pathways thereby maintaining a fine balance of cell survival and death. Autophagy is a complex cell-killing mechanism that has both cytoprotective and cytotoxic roles. Similarly, autophagy can lead to the induction of both chemosensitization and chemoresistance in cancer cells upon therapeutic intervention. Recently the role of lncRNAs in the regulation of autophagy has also surfaced. Thus, lncRNAs can be used in cancer therapeutics to alleviate the challenges of chemoresistance by targeting the autophagosomal axis. In this chapter, we discuss about the role of lncRNAs in autophagy-mediated cancer drug resistance and its implication in targeted cancer therapy.

Targeting Autophagy Using Long Non-Coding RNAs (LncRNAs): New Landscapes in the Arena of Cancer Therapeutics

Cancer has become a global health hazard accounting for 10 million deaths in the year 2020. Although different treatment approaches have increased patient overall survival, treatment for advanced stages still suffers from poor clinical outcomes. The ever-increasing prevalence of cancer has led to a reanalysis of cellular and molecular events in the hope to identify and develop a cure for this multigenic disease. Autophagy, an evolutionary conserved catabolic process, eliminates protein aggregates and damaged organelles to maintain cellular homeostasis. Accumulating evidence has implicated the deregulation of autophagic pathways to be associated with various hallmarks of cancer. Autophagy exhibits both tumor-promoting and suppressive effects based on the tumor stage and grades. Majorly, it maintains the cancer microenvironment homeostasis by promoting viability and nutrient recycling under hypoxic and nutrient-deprived conditions. Recent investigations have discovered long non-coding RNAs (lncRNAs) as master regulators of autophagic gene expression. lncRNAs, by sequestering autophagy-related microRNAs, have been known to modulate various hallmarks of cancer, such as survival, proliferation, EMT, migration, invasion, angiogenesis, and metastasis. This review delineates the mechanistic role of various lncRNAs involved in modulating autophagy and their related proteins in different cancers.

Investigation of apoptotic and antiproliferative effects of Turkish natural tetraploids Trifolium pratense L. extract on C6 glioblastoma cells via light and electron microscopy

Glioblastoma (GBM) is the most common type of primary brain tumors in adults, characterized by its ability to proliferate rapidly and its tendency to aggressively and strongly invaded the surrounding brain tissue. The standard treatment approach of GBM is surgical resection followed by simultaneous chemotherapy and radiation. However, a significant number of GBM cases develop resistance to currently used chemotherapeutic drugs. Therefore, there is a need for the development of new chemotherapeutic agents. Trifoliumpratense L. is an endemic plant containing various isoflavones such as biochanin A, genistein, daidzein, and formononetin in high concentrations, and it has been shown in various studies that these molecules can function as anticancer agents. The present study was designed to determine the effect of the possible anticarcinogenic effects of the Trifolium pratense L. which grown in our country and to obtain new treatment approaches alternative to the classical treatment protocols applied in the treatment of GBM. C6 glioblastoma cells were cultured with Trifolium pratense L. Cell proliferation, apoptotic cell morphology, and cell structure were evaluated with CCK8, Annexin V, cytochrome c, CD117, and Betatubulin labeling, respectively. And also, investigated effects of this Turkish tetraploid on GBM by TEM. Decreased cell proliferation and increased number of apoptotic cells were observed depending on the increasing doses of Trifolium pratense L. In addition, intense morphological changes were detected depending on increasing doses. In this context, we believe that the plant Trifolium pratense L., may be a new alternative and adjuvant agent for the treatment of GBM.

A small-molecule drug inhibits autophagy gene expression through the central regulator TFEB

Autophagy supports the fast growth of established tumors and promotes tumor resistance to multiple treatments. Inhibition of autophagy is a promising strategy for tumor therapy. However, effective autophagy inhibitors suitable for clinical use are currently lacking. There is a high demand for identifying novel autophagy drug targets and potent inhibitors with drug-like properties. The transcription factor EB (TFEB) is the central transcriptional regulator of autophagy, which promotes lysosomal biogenesis and functions and systematically up-regulates autophagy. Despite extensive evidence that TFEB is a promising target for autophagy inhibition, no small molecular TFEB inhibitors were reported. Here, we show that an United States Food and Drug Administration (FDA)-approved drug Eltrombopag (EO) binds to the basic helix-loop-helix-leucine zipper domain of TFEB, specifically the bottom surface of helix-loop-helix to clash with DNA recognition, and disrupts TFEB-DNA interaction in vitro and in cellular context. EO selectively inhibits TFEB's transcriptional activity at the genomic scale according to RNA sequencing analyses, blocks autophagy in a dose-dependent manner, and increases the sensitivity of glioblastoma to temozolomide in vivo. Together, this work reveals that TFEB is targetable and presents the first direct TFEB inhibitor EO, a drug compound with great potential to benefit a wide range of cancer therapies by inhibiting autophagy.

Anticancer Mechanism of Flavonoids on High-Grade Adult-Type Diffuse Gliomas

High-grade adult-type diffuse gliomas are the most common and deadliest malignant adult tumors of the central nervous system. Despite the advancements in the multimodality treatment of high-grade adult-type diffuse gliomas, the five-year survival rates still remain poor. The biggest challenge in treating high-grade adult-type diffuse gliomas is the intra-tumor heterogeneity feature of the glioma tumors. Introducing dietary flavonoids to the current high-grade adult-type diffuse glioma treatment strategies is crucial to overcome this challenge, as flavonoids can target several molecular targets. This review discusses the anticancer mechanism of flavonoids (quercetin, rutin, chrysin, apigenin, naringenin, silibinin, EGCG, genistein, biochanin A and C3G) through targeting molecules associated with high-grade adult-type diffuse glioma cell proliferation, apoptosis, oxidative stress, cell cycle arrest, migration, invasion, autophagy and DNA repair. In addition, the common molecules targeted by the flavonoids such as Bax, Bcl-2, MMP-2, MMP-9, caspase-8, caspase-3, p53, p38, Erk, JNK, p38, beclin-1 and LC3B were also discussed. Moreover, the clinical relevance of flavonoid molecular targets in high-grade adult-type diffuse gliomas is discussed with comparison to small molecules inhibitors: ralimetinib, AMG232, marimastat, hydroxychloroquine and chloroquine. Despite the positive pre-clinical results, further investigations in clinical studies are warranted to substantiate the efficacy and safety of the use of flavonoids on high-grade adult-type diffuse glioma patients.

RUNX1/CD44 axis regulates the proliferation, migration, and immunotherapy of gliomas: A single-cell sequencing analysis

Background

Glioma is one of the most common, primary, and lethal adult brain tumors because of its extreme aggressiveness and poor prognosis. Several recent studies relevant to the immune function of CD44, a transmembrane glycoprotein as a significant hyaluronic acid receptor, have achieved great success, revealing the critical role of CD44 in immune infiltration in gliomas. The overexpression of CD44 has been verified to correlate with cancer aggressiveness and migration, while the clinical and immune features of CD44 expression have not yet been thoroughly characterized in gliomas.

Methods

Molecular and clinical data of glioma collected from publicly available genomic databases were analyzed.

Results

CD44 was up-expressed in malignant gliomas, notably in the 1p/19q non-codeletion cases, isocitrate dehydrogenase (IDH) wild-type, and mesenchymal subtypes in GBM samples. CD44 expression level strongly correlates with stromal and immune cells, mainly infiltrating the glioma microenvironment by single-cell sequencing analysis. Meanwhile, CD44 can be a promising biomarker in predicting immunotherapy responses and mediating the expression of PD-L1. Finally, RUNX1/CD44 axis could promote the proliferation and migration of gliomas.

Conclusions

Therefore, CD44 was responsible for glioma growth and progression. It could potentially lead to a novel target for glioma immunotherapy or a prognostic biomarker.

The functions and molecular mechanisms of Tribbles homolog 3 (TRIB3) implicated in the pathophysiology of cancer

Currently, cancer ranks as the second leading cause of death worldwide, and at the same time, the burden of cancer continues to increase. The underlying molecular pathways involved in the initiation and development of cancer are the subject of considerable research worldwide. Further understanding of these pathways may lead to new cancer treatments. Growing data suggest that Tribble's homolog 3 (TRIB3) is essential in oncogenesis in many types of cancer. The mammalian tribbles family's proteins regulate various cellular and physiological functions, such as the cell cycle, stress response, signal transduction, propagation, development, differentiation, immunity, inflammatory processes, and metabolism. To exert their activities, Tribbles proteins must alter key signaling pathways, including the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3 kinase (PI3K)/AKT pathways. Recent evidence supports that TRIB3 dysregulation has been linked to various diseases, including tumor development and chemoresistance. It has been speculated that TRIB3 may either promote or inhibit the onset and development of cancer. However, it is still unclear how TRIB3 performs this dual function in cancer. In this review, we present and discuss the most recent data on the role of TRIB3 in cancer pathophysiology and chemoresistance. Furthermore, we describe in detail the molecular mechanism TRIB3 regulates in cancer.

Co-delivery of ibrutinib and hydroxychloroquine by albumin nanoparticles for enhanced chemotherapy of glioma

Ibrutinib (IBR) is an oral covalent inhibitor of Bruton's tyrosine kinase (BTK) that has been approved for the treatment of hematological malignancies. It was reported that IBR exhibited great therapeutic potential for glioma. However, the poor water solubility and high hepatic first-pass effect restrict its anti-glioma application. Meanwhile, IBR induces cytoprotective autophagy through Akt/mTOR signaling pathway, thus leading to a compromised antitumor effect. Herein, we aimed to develop a human serum albumin (HSA) based co-delivery system (IBR&HCQ HSA NPs) encapsulating IBR and hydroxychloroquine (HCQ). The bioavailability of IBR was largely improved, and enhanced sensitivity of glioma to IBR was achieved due to inhibition effect of HCQ on IBR-induced pro-survival autophagy. The physicochemical properties of IBR&HCQ HSA NPs were characterized to optimize the formulation. Biodistribution investigation revealed that HSA NPs (20 mg/kg, i.v.) dramatically increased the accumulation of IBR in glioma, which was 5.59 times higher than that of free IBR (100 mg/kg, i.g.). CCK-8 and apoptosis assays demonstrated that IBR&HCQ HSA NPs showed maximal cytotoxicity to C6 cells. In vivo studies indicated that the survival time was significantly prolonged in IBR&HCQ HSA NPs treated mice compared to those treated with IBR HSA NPs. Taken together, the HSA-based drug delivery system of IBR and HCQ opens a new avenue for efficient treatment of glioma.

Investigation of chemoresistance to first-line chemotherapy and its possible association with autophagy in high-risk neuroblastoma

High-risk neuroblastoma (NB) is sensitive to chemotherapy but susceptible to chemoresistance. In this study, we aimed to analyze the incidence of chemoresistance in high-risk NB patients and to explore the role of autophagy in NB chemoresistance. We retrospectively analyzed the incidence of changing the chemotherapy regimen due to disease stabilization or disease progression during induction chemotherapy in high-risk NB patients, which was expressed as the chemoresistance rate. The autophagy levels were probed in tumor cells exposed to first-line chemotherapy agents. The sensitivity of tumor cells to chemotherapy agents and apoptosis rate were observed after inhibiting autophagy by transfection of shRNA or chloroquine (CQ). This study included 247 patients with high-risk NB. The chemoresistance rates of patients treated with cyclophosphamide + adriamycin + vincristine (CAV) alternating with etoposide + cisplatin (EP) (Group 1) and CAV alternating with etoposide + ifosfamide + cisplatin (VIP) (Group 2) was 61.5% and 39.9% (P = 0.0009), respectively. Group 2 had better survival rates than group 1. After exposure to cisplatin, cyclophosphamide, and etoposide, the autophagy-related proteins LC3-I, LC3-II, and Beclin-1 were upregulated, and the incidence of autophagy vesicle formation and the expression of P62 were increased. Chemotherapeutic agents combined with CQ significantly increased the chemotherapeutic sensitivity of tumor cells and increased the cell apoptosis. The downregulated expression of Beclin-1 increased the sensitivity of tumor cells to chemotherapeutics. Our results suggest that increasing the chemotherapy intensity can overcome resistance to NB. Inhibition of autophagy is beneficial to increase the sensitivity of NB to chemotherapy agents.

TfR Aptamer Enhanced Blood-Brain Barrier Penetration of Biomimetic Nanocomplexes for Intracellular Transglutaminase 2 Imaging and Silencing in Glioma

Engineering a versatile nanocomplex integrating effective penetration of the blood-brain barrier (BBB), accurate diagnosis, and boosting therapy has always been an intractable challenge in glioblastoma multiforme (GBM). Herein, biomimetic nanocomplexes (TMPsM) for single intracellular transglutaminase 2 (TG2)-triggered self-assembly imaging and RNAi therapy for GBM are subtly developed. To prove the concept, transferrin receptor (TfR) aptamer-modified brain metastatic tumor cell membrane is prepared as the shell for dual BBB targeting capability and prolonged blood retention time. Upon targeting entering into GBM, hollow MnO₂ is decomposed to release KKGKGQQ-tetraphenylethene (Pep-TPE) and siRNA. Owing to TG2 dependence, the non-emissive Pep-TPE would be self-aggregated to induce the emission turn-on in GBM that contain overexpressed TG2. The resulting aggregation-induced emission fluorescence imaging with a high signal-to-noise ratio can achieve the precise localization of the tumor and dynamic detection of TG2 activity, thereby allowing the GBM accurate diagnosis. Notably, the TG2 can be silenced by the released siRNA to cause cell apoptosis and increase chemotherapeutic sensitivity, ultimately realizing excellent antitumor efficacy. In vitro and in vivo results demonstrate that the as-prepared TMPsM indeed possess superior BBB penetration, precise diagnosis, and effective therapy of GBM. The proposed strategy may pioneer a new path for the theranostics of brain tumors.

Recent advances in glioblastoma multiforme therapy: A focus on autophagy regulation

Despite conventional treatment options including chemoradiation, patients with the most aggressive primary brain tumor, glioblastoma multiforme (GBM), experience an average survival time of less than 15 months. Regarding the malignant nature of GBM, extensive research and discovery of novel treatments are urgently required to improve the patients' prognosis. Autophagy, a crucial physiological pathway for the degradation and recycling of cell components, is one of the exciting targets of GBM studies. Interventions aimed at autophagy activation or inhibition have been explored as potential GBM therapeutics. This review, which delves into therapeutic techniques to block or activate autophagy in preclinical and clinical research, aims to expand our understanding of available therapies battling GBM.

Regulation of temozolomide resistance via lncRNAs: Clinical and biological properties of lncRNAs in gliomas (Review)

Gliomas are a primary types of intracranial malignancies and are characterized by a poor prognosis due to aggressive recurrence profiles. Temozolomide (TMZ) is an auxiliary alkylating agent that is extensively used in conjunction with surgical resection and forms the mainstay of clinical treatment strategies for gliomas. However, the frequent occurrence of TMZ resistance in clinical practice limits its therapeutic efficacy. Accumulating evidence has demonstrated that long non‑coding RNAs (lncRNAs) can play key and varied roles in glioma progression. lncRNAs have been reported to inhibit glioma progression by targeting various signaling pathways. In addition, the differential expression of lncRNAs has also been found to mediate the resistance of glioma to several chemotherapeutic agents, particularly to TMZ. The present review article therefore summarizes the findings of previous studies in an aim to report the significance and function of lncRNAs in regulating the chemoresistance of gliomas. The present review may provide further insight into the clinical treatment of gliomas.

Polymeric and small molecule-conjugates of temozolomide as improved therapeutic agents for glioblastoma multiforme

Temozolomide (TMZ), an imidazotetrazine, is a second-generation DNA alkylating agent used as a first-line treatment of glioblastoma multiforme (GBM). It was approved by FDA in 2005 and declared a blockbuster drug in 2008. Although TMZ has shown 100% oral bioavailability and crosses the blood-brain barrier effectively, however it suffers from limitations such as a short half-life (∼1.8 h), rapid metabolism, and lesser accumulation in the brain (∼10-20%). Additionally, development of chemoresistance has been associated with its use. Since it is a potential chemotherapeutic agent with an unmet medical need, advanced delivery strategies have been explored to overcome the associated limitations of TMZ. Nanocarriers including liposomes, solid lipid nanoparticles (SLNs), nanostructure lipid carriers (NLCs), and polymeric nanoparticles have demonstrated their ability to improve its circulation time, stability, tissue-specific accumulation, sustained release, and cellular uptake. Because of the appreciable water solubility of TMZ (∼5 mg/mL), the physical loading of TMZ in these nanocarriers is always challenging. Alternatively, the conjugation approach, wherein TMZ has been conjugated to polymers or small molecules, has been explored with improved outcomes in vitro and in vivo. This review emphasized the practical evidence of the conjugation strategy to improve the therapeutic potential of TMZ in the treatment of glioblastoma multiforme.

Protein Quality Control in Glioblastoma: A Review of the Current Literature with New Perspectives on Therapeutic Targets

Protein quality control allows eukaryotes to maintain proteostasis under the stress of constantly changing conditions. In this review, we discuss the current literature on PQC, highlighting flaws that must exist for malignancy to occur. At the nidus of PQC, the expression of BAG1-6 reflects the cell environment; each isoform directs proteins toward different, parallel branches of the quality control cascade. The sum of these branches creates a net shift toward either homeostasis or apoptosis. With an established role in ALP, Bag3 is necessary for cell survival in stress conditions including those of the cancerous niche (i.e., hypoxia, hypermutation). Evidence suggests that excessive Bag3–HSP70 activity not only sustains, but also propagates cancers. Its role is anti-apoptotic—which allows malignant cells to persist—and intercellular—with the production of infectious ‘oncosomes’ enabling cancer expansion and recurrence. While Bag3 has been identified as a key prognostic indicator in several cancer types, its investigation is limited regarding glioblastoma. The cochaperone HSP70 has been strongly linked with GBM, while ALP inhibitors have been shown to improve GBM susceptibility to chemotherapeutics. Given the highly resilient, frequently recurrent nature of GBM, the targeting of Bag3 is a necessary consideration for the successful and definitive treatment of GBM.

Hispidulin Enhances Temozolomide (TMZ)-Induced Cytotoxicity against Malignant Glioma Cells In Vitro by Inhibiting Autophagy

Temozolomide (TMZ), an oral alkylating agent, is the widely used first-line chemotherapeutic reagent for glioma in clinical practice. However, TMZ-induced autophagy is another cellular process favoring glioma cell survival. This study aimed to explore whether hispidulin can facilitate TMZ-induced cell death of glioma. The MTT assay showed that coadministration with hispidulin and TMZ could significantly decrease the viability of glioma U87MG cells. Meanwhile, hispidulin administration was also observed to promote TMZ-induced apoptosis. Furthermore, additional hispidulin treatment further elevated TMZ-induced expression of Bax, cleaved-caspase-9, and cleaved-caspase-3 protein but decreased Bcl-2 protein expression in U87MG cells. We also observed that hispidulin suppressed TMZ-induced autophagy to promote apoptosis, as showed by decreased AVOs and LC3B-I/II protein expression. These results collectively suggested that the combination of hispidulin and TMZ could improve the antitumor efficiency of TMZ against malignant gliomas.

Abnormally Expressed Ferroptosis-Associated FANCD2 in Mediating the Temozolomide Resistance and Immune Response in Glioblastoma

Ferroptosis-related genes (FRGs) have been identified as potential targets involved in oncogenesis and cancer therapeutic response. Nevertheless, the specific roles and underlying mechanisms of FRGs in GBM and temozolomide (TMZ) resistance remain unclear. Through comprehensive bioinformatics, we found that ferroptosis-related Fanconi anemia complementation group D2 (FANCD2) was significantly up-regulated in GBM tissues, and the high expression level of FANCD2 was related to the poor prognosis in primary and recurrent GBM patients. Furthermore, FANCD2 could promote TMZ resistance by attenuating ferroptosis in GBM cells. Knockdown of FANCD2 could increase reactive oxygen species (ROS) levels and inhibit cell survival. The two characteristics were associated with ferroptosis in TMZ-resistant GBM cells T98G-R and U118-R. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that aberrantly expressed FANCD2 was potentially linked with several cancer-associated signaling pathways, including chromosome segregation, DNA replication, and cell cycle transition. In addition, we demonstrated that FANCD2 expression was positively correlated with several tumor-infiltrating lymphocytes (TILs) and multiple immune-associated signatures in GBM. Therefore, up-regulated FANCD2 could protect GBM cells from ferroptosis and promote TMZ resistance. FANCD2 may be a novel therapeutic target in GBM.