Investigating the impact of MCTP2 on immune suppression and drug resistance in glioblastoma.

Glioblastoma stem cells (GSCs) play a key role in glioblastoma (GBM) resistance to temozolomide (TMZ) chemotherapy. With the increase in research on the tumour microenvironment, exosomes secreted by GSCs have become a new focus in GBM research. However, the molecular mechanism by which GSCs affect drug resistance in GBM cells via exosomes remains unclear. Using bioinformatics analysis, we identified the specific expression of ABCB4 in GSCs. Subsequently, we established GSC cell lines and used ultracentrifugation to extract secreted exosomes. We conducted in vitro and in vivo investigations to validate the promoting effect of ABCB4 and ABCB4-containing exosomes on TMZ resistance. Finally, to identify the transcription factors regulating the transcription of ABCB4, we performed luciferase assays and chromatin immunoprecipitation-quantitative PCR. Our results indicated that ABCB4 is highly expressed in GSCs. Moreover, high expression of ABCB4 promoted the resistance of GSCs to TMZ. Our study found that GSCs can also transmit their highly expressed ABCB4 to differentiated glioma cells (DGCs) through exosomes, leading to high expression of ABCB4 in these cells and promoting their resistance to TMZ. Mechanistic studies have shown that the overexpression of ABCB4 in GSCs is mediated by the transcription factor ATF3. In conclusion, our results indicate that GSCs can confer resistance to TMZ in GBM by transmitting ABCB4, which is transcribed by ATF3, through exosomes. This mechanism may lead to drug resistance and recurrence of GBM. These findings contribute to a deeper understanding of the mechanisms underlying drug resistance in GBM and provide novel insights into its treatment.

Background Intratumoral heterogeneity plays an important role in glioblastoma (GB) resistance to standard therapy consisting of irradiation and chemotherapy with temozolomide (TMZ). However, classical in vitro GB models fail to represent the complex cellular composition of tumors in vivo, which hinders relevant examination of GB therapeutic response. To overcome these limitations, we studied the effects of irradiation and TMZ in a novel patient-derived organoid model. Material and Methods We established a patient-derived GB organoid model by a protocol recently published by Jacob et al. Original tumor tissue and tissue-derived organoids were compared by immunofluorescence staining of selected cell type markers and qPCR analysis of expression levels of a panel of selected target genes, including 15 genes defining GB subtypes. To analyze GB therapeutic response, organoids from 11 patients were exposed to a single dose of irradiation (10 Gy), one-week treatment with TMZ (50 µM) or their combination. The effects of therapy were assessed by viability and invasion assays. Expression levels of a number of genes related to GB subtypes, epithelial-mesenchymal transition, stemness, DNA damage responses, cell cycle, cytokines, and cell markers of the tumor microenvironment (TME) were compared between treated organoids and untreated controls. In addition, the heterogeneity of the TME and its responses to treatment were investigated by spatially resolved transcriptomics with in situ sequencing (ISS) methodology. Results Organoids recapitulate inter-patient variability and reflect the cellular composition and gene expression levels of the tumor tissue from which they were derived. GB stem cells and differentiated cancer cells are present in organoids along with various cells of the TME, e.g., macrophages and microglia, lymphocytes, and endothelial cells. Irradiation and TMZ showed no significant effects on organoid viability and invasion. However, some target genes were differentially expressed in the treated organoids, such as E3 ubiquitin-protein ligase MDM2 and cyclin-dependent kinase inhibitor 1A (CDKN1A). To our knowledge, we are the first to apply spatially resolved transcriptomics (ISS) to formalin-fixed, paraffin-embedded sections of (un)treated GB organoids. Our results elucidate the role of the TME in GB therapeutic response and shed light on potential mechanism underlying GB therapy resistance. Conclusion Patient-derived GB organoids recapitulate the key characteristics and complex composition of patient’s tumor tissue, providing a valuable platform for studies of GB therapeutic response and resistance.

BackgroundCircular RNAs (circRNAs) can influence a variety of biological functions and act as a significant role in the progression and recurrence of glioblastoma (GBM). However, few coding circRNAs have been discovered in cancer, and their role in GBM is still unknown. The aim of this study was to identify coding circRNAs and explore their potential roles in the progression and recurrence of GBM.MethodsCircSPECC1 was screened via circRNAs microarray of primary and recurrent GBM samples. To ascertain the characteristics and coding ability of circSPECC1, we conducted a number of experiments. Afterward, through in vivo and in vitro experiments, we investigated the biological functions of circSPECC1 and its encoded novel protein (SPECC1-415aa) in GBM, as well as their effects on TMZ sensitivity.ResultsBy analyzing primary and recurrent GBM samples via circRNAs microarray, circSPECC1 was found to be a downregulated circRNA with coding potential in recurrent GBM compared with primary GBM. CircSPECC1 suppressed the proliferation, migration, invasion, and colony formation abilities of GBM cells by encoding a new protein known as SPECC1-415aa. CircSPECC1 restored TMZ sensitivity in TMZ-resistant GBM cells by encoding the new protein SPECC1-415aa. The m6A reader protein IGF2BP1 can bind to circSPECC1 to promote its expression and stability. Mechanistically, SPECC1-415aa can bind to ANXA2 and competitively inhibit the binding of ANXA2 to EGFR, thus resulting in the inhibition of the phosphorylation of EGFR (Tyr845) and its downstream pathway protein AKT (Ser473). In vivo experiments showed that the overexpression of circSPECC1 could combine with TMZ to treat TMZ-resistant GBM, thereby restoring the sensitivity of TMZ-resistant GBM to TMZ.ConclusionsCircSPECC1 was downregulated in recurrent GBM compared with primary GBM. The m6A reader protein IGF2BP1 could promote the expression and stability of circSPECC1. The sequence of SPECC1-415aa, which is encoded by circSPECC1, can inhibit the binding of ANXA2 to EGFR by competitively binding to ANXA2 and inhibiting the phosphorylation of EGFR and AKT, thereby restoring the sensitivity of TMZ-resistant GBM cells to TMZ.

OBJECTIVE Defects in the apoptotic machinery and augmented survival signals contribute to drug resistance in glioblastoma (GBM). Moreover, another complexity related to GBM treatment is the concept that GBM development and recurrence may arise from the expression of GBM stem cells (GSCs). Therefore, the use of a multifaceted approach or multitargeted agents that affect specific tumor cell characteristics will likely be necessary to successfully eradicate GBM. The objective of this study was to investigate the usefulness of sulforaphane (SFN)-a constituent of cruciferous vegetables with a multitargeted effect-as a therapeutic agent for GBM. METHODS The inhibitory effects of SFN on established cell lines, early primary cultures, CD133-positive GSCs, GSC-derived spheroids, and GBM xenografts were evaluated using various methods, including GSC isolation and the sphere-forming assay, analysis of reactive oxygen species (ROS) and apoptosis, cell growth inhibition assay, comet assays for assessing SFN-triggered DNA damage, confocal microscopy, Western blot analysis, and the determination of in vivo efficacy as assessed in human GBM xenograft models. RESULTS SFN triggered the significant inhibition of cell survival and induced apoptotic cell death, which was associated with caspase 3 and caspase 7 activation. Moreover, SFN triggered the formation of mitochondrial ROS, and SFN-triggered cell death was ROS dependent. Comet assays revealed that SFN increased single- and double-strand DNA breaks in GBM. Compared with the vehicle control cells, a significantly higher amount of γ-H2AX foci correlated with an increase in DNA double-strand breaks in the SFN-treated samples. Furthermore, SFN robustly inhibited the growth of GBM cell-induced cell death in established cell cultures and early-passage primary cultures and, most importantly, was effective in eliminating GSCs, which play a major role in drug resistance and disease recurrence. In vivo studies revealed that SFN administration at 100 mg/kg for 5-day cycles repeated for 3 weeks significantly decreased the growth of ectopic xenografts that were established from the early passage of primary cultures of GBM10. CONCLUSIONS These results suggest that SFN is a potent anti-GBM agent that targets several apoptosis and cell survival pathways and further preclinical and clinical studies may prove that SFN alone or in combination with other therapies may be potentially useful for GBM therapy.

A significant hurdle in treating glioblastoma (GBM) is addressing the development of drug resistance. In this study, the role of Family of Sequence Similarity 20, Member C (Fam20C) as a central player in bevacizumab resistant GBM mouse model is investigated. In vivo analyses confirm that Fam20C upregulation accelerates drug resistance and correlates with tumor progression. Proteomic analyses of conditioned media and cell lysates subsequent to Fam20C knockout (KO) in GBM cells reveal the regulatory role of Fam20C in both intracellular and extracellular aspects of epithelial‐mesenchymal transition (EMT) and genes associated with AKT signaling. Moreover, In vitro experiments demonstrate that Fam20C activates the AKT signaling pathway, promoting cell proliferation. Elevated levels of Fam20C are observed in human GBM, particularly in the mesenchymal subtype, which correlates with diminished survival rates and increased resistance to various drugs, including temozolomide (TMZ), bevacizumab, epidermal growth factor receptor (EGFR) inhibitors, and other antibody‐based drugs. Notably, even in cases of resistance to gefitinib and hepatocyte growth factor (HGF) antibodies, Fam20C expression is elevated. These findings highlight the pivotal role of Fam20C in driving drug resistance in GBM, suggesting it as a promising target for combination therapies aimed at surmounting this formidable resistance barrier.

Adapted oxidative phosphorylation (OXPHOS) and tricarboxylic acid (TCA) cycle activations are essential tumor microenvironments for abnormal energy consumption to acquire malignancy and drug resistance during cancer development and progression. To elucidate the molecular mechanism related to the mitochondrial metabolic dynamics and drug resistance in glioblastoma (GBM), a longitudinal GBM orthotopic mouse model with acquired resistance to bevacizumab is established. The longitudinal proteomic analysis results show that OXPHOS, TCA, and calcium signaling gene sets are enriched in the bevacizumab pre‐resistance phase for preparing resistance phase. Then, the APEX system to GBM to biotinylate and purify proteins of the mitochondria matrix is applied. The organelle specific proteomic analysis shows that the pore‐forming subunits of the mitochondrial calcium uniporter protein (MCU) are essential for acquiring bevacizumab resistance. Additionally, a combination effect of hypoxia and the MCU‐specific inhibitor DS16570511 in vitro shows that cell growth and proliferation are reduced via inhibition of NF‐κB and CEBP/β signaling pathways. In conclusion, the hypoxic tumor microenvironment induced by bevacizumab treatment affects mitochondrial metabolic dynamics, and targeting MCU is a promising therapeutic option in combination with bevacizumab in recurrent GBM.

Glioblastoma multiforme (GBM) is recognized as the most common and lethal form of central nervous system cancer. Currently used surgical techniques, chemotherapeutic agents, and radiotherapy strategies have done very little in extending the life expectancies of patients diagnosed with GBM. The difficulty in treating this malignant disease lies both in its inherent complexity and numerous mechanisms of drug resistance. In this review, we summarize several of the primary mechanisms of drug resistance. We reviewed available published literature in the English language regarding drug resistance in glioblastoma. The reasons for drug resistance in glioblastoma include drug efflux, hypoxic areas of tumor cells, cancer stem cells, DNA damage repair, and miRNAs. Many potential therapies target these mechanisms, including a series of investigated alternative and plant-derived agents. Future research and clinical trials in glioblastoma patients should pursue combination of therapies to help combat drug resistance. The emerging new data on the potential of plant-derived therapeutics should also be closely considered and further investigated.

Glioblastoma (GBM) represents the main form of brain tumors in adults, and one of the most aggressive cancers overall. The treatment of GBM is a combination of surgery (when possible), chemotherapy (usually Temozolomide, TMZ) and radiotherapy (RT). However, despite this heavy treatment, GBM invariably recur and the median length of survival following diagnosis is 12 to 15 months, with less than 10% of people surviving longer than five years. GBM is extremely resistant to most treatments because of its heterogeneous nature, which is associated with extreme clonal plasticity and the presence of cancer stem cells, refractory to TMZ- and RT-induced cell death. In this review, we explore the mechanisms by which cancer cells, and especially GBM, can acquire resistance to treatment. We describe and discuss the concept of persister/tolerant cells that precede and/or accompany the acquisition of resistance. Persister/tolerant cells are cancer cells that are not eliminated by treatment(s) because of different mechanisms ranging from dormancy/quiescence to senescence. We discuss the possibility of targeting these mechanisms in new therapeutic regimen.

Background: Resistance to single-agent targeted cancer therapy is almost universal. Resistance can occur when drug-resistant tumor cell subpopulations expand to drive recurrence in a process akin to Darwinian-type evolution under the selection pressure of the drug. An alternative resistance mechanism is the one in which cancer cells targeted by the inhibitor adapt to that drug, so as to maintain the signal flux through those networks that are required for tumor maintenance and growth. The main goal of this study is to identify the mechanisms of resistance in a targeted therapy by analyzing single cells and to provide a strategy to design a more effective therapy that suppresses resistance. Methods: We investigated a clinically relevant model of acquired cancer drug resistance in glioblastoma (GBM). GBM39 is a human-derived primary GBM line that is maintained by serial transplantation in xenografts. GBM39 expresses high levels of the epidermal growth factor receptor (EGFR) variant(v)III oncogene, which sensitizes tumor cells to inhibitors of the mammalian target of rapamycin (mTOR). Therefore, we used this model to study acquired resistance to the mTOR kinase inhibitor CC214-2, which suppresses the proliferation of EGFRvIII expressing GBMs. We utilized a microfluidic device as a main tool that enables multiplex single cell proteomics. Relative to bulk assays, it can provide deeper insights into the signaling activity within a phosphoprotein signaling network, and how that activity is influenced by a drug. In addition to providing average protein levels, such assays also yield information on network signaling coordination that can be extracted from the variance for any given protein, as well as correlations between proteins. We determined the structure of the hyperactivated phosphoprotein signaling networks from statistical numbers of single cancer cells separated from the tumor for the untreated vehicle, during response to CC214-2, and after resistance to CC214-2. Results: We find evidence that the tumors can rapidly adapt (within 2-3 days) to specific targeted inhibitors. The details of how the cells adapt, which are uniquely resolved by the single cell assays, can suggest effective therapy combinations. For a GBM murine model, tumor cells rapidly adapted to mTOR inhibition by activating ERK/Src signaling, suggesting that mTOR and ERK/Src signaling provided two independent druggable pathways for that tumor. Consonant with this hypothesis, we devised three therapeutic combinations and showed them to be highly effective in causing sustained clinical remission in vivo. A retrospective analysis revealed that mTOR signaling was a major driver of tumor growth in the untreated tumor, while ERK/Src signaling promoted resistance to mTOR inhibition. An additional study of a low passage, patient derived GBM cell line was also shown to exhibit rapid adaptation to single-agent targeted therapy in a manner that suggested effective combination therapies for cell killing. Finally, the analysis was shown to be feasible on a freshly resected patient GBM tumor. Conclusions: The data and analysis presented here provide evidence that tumor cells can respond rapidly to a therapy and restores the growth characteristics temporarily disrupted by the therapy. This resistance mechanism is intrinsic; the same cells that respond to the therapy also adapt and develop resistance to it. For the GBM models explored here, a single cell proteomics analysis of the phosphoprotein signaling networks can resolve the independent signaling modes that drive tumor growth in both the untreated and drug resistant states. Such an analysis can be rapidly carried out using untreated tumor biopsies, and so may represent a new approach for guiding the selection of targeted combination therapies with low anticipated resistance. Citation Format: Young Shik Shin, Wei Wei, Beatrice Gini, Paul Mischel, James Heath. Single cell phosphoproteomics identifies adaptive network dynamics of mTOR inhibitor resistance and defines effective combination therapy in glioblastoma. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; Jun 18-21, 2014; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(4 Suppl): Abstract nr PR09.

Glioblastoma (GB) is one of the deadliest brain cancers to afflict humans, and it has a very poor survival rate even with treatment. The extracellular adenosine-generating enzyme CD73 is involved in many cellular functions that can be usurped by tumors, including cell adhesion, proliferation, invasion, and angiogenesis. We set out to determine the role of CD73 in GB pathogenesis. To do this, we established a unique GB mouse model (CD73-FLK) in which we spatially expressed CD73 on endothelial cells in CD73-/- mice. This allowed us to elucidate the mechanism of host CD73 versus GB-expressed CD73 by comparing GB pathogenesis in WT, CD73-/-, and CD73-FLK mice. GB in CD73-/- mice had decreased tumor size, decreased tumor vessel density, and reduced tumor invasiveness compared with GB in WT mice. Interestingly, GBs in CD73-FLK mice were much more invasive and caused complete distortion of the brain morphology. We showed a 20-fold upregulation of A2B AR on GB compared with sham, and its activation induced matrix metalloproteinase-2, which enhanced GB pathogenesis. Inhibition of A2B AR signaling decreased multidrug resistance transporter protein expression, including permeability glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1). Further, we showed that blockade of A2B AR signaling potently increased GB cell death induced by the chemotherapeutic drug temozolomide. Together, these findings suggest that CD73 and A2B AR play a multifaceted role in GB pathogenesis and progression and that targeting the CD73-A2B AR axis can benefit GB patients and inform new approaches for therapy to treat GB patients.SIGNIFICANCE STATEMENT Glioblastoma (GB) is the most devastating primary brain tumor. GB patients' median survival is 16 months even with treatment. It is critical that we develop prophylaxes to advance GB treatment and improve patient survival. CD73-generated adenosine has been implicated in cancer pathogenesis, but its role in GB was not ascertained. Here, we demonstrated that host CD73 plays a prominent role in multiple areas of glioblastoma pathogenesis, including promoting GB growth, its angiogenesis, and its invasiveness. We found a 20-fold increase in A2B adenosine receptor (AR) expression on GB compared with sham, and its inhibition increased GB chemosensitivity to temozolomide. These findings strongly indicate that blockade or inhibition of CD73 and the A2B AR are prime targets for future GB therapy.

Glioblastoma (GBM) is one of the most common and malignant types of primary cancer in the central nervous system; however, the clinical outcomes of patients with GBM remain poor. Circular RNAs (circRNAs) have been revealed to serve important roles in diverse biological processes, such as regulating cell proliferation, epithelial-mesenchymal transition and tumor development. However, the underlying biological function of circRNA filamin A (circFLNA) and its potential role in GBM remain to be determined. The present study aimed to identify differentially expressed circRNAs in GBM. Reverse transcription-quantitative PCR was used to analyze the expression levels of circFLNA. The results demonstrated that the expression levels of circFLNA were significantly upregulated in clinical GBM samples and GBM cells compared with adjacent healthy brain tissues and normal human astrocytes, respectively. The results of the Cell Counting Kit-8 and Transwell assays revealed that circFLNA knockdown significantly inhibited the proliferative and invasive abilities of GBM cell lines. Moreover, high circFLNA expression levels were associated with a worse prognosis in GBM. MicroRNA (miR)-199-3p was subsequently predicted to be target of circFLNA. The inhibitory effect of miR-199-3p on cell proliferation and invasion was partially reversed following circFLNA knockdown. In conclusion, the findings of the present study identified novel roles for circFLNA in GBM and indicated that the circFLNA/miR-199-3p signaling axis may serve an important role in GBM progression. Therefore, circFLNA may represent a novel target for the diagnosis and treatment of GBM.

Phenotypic plasticity plays a pivotal role in cancer, enabling tumor cells to adapt to environmental pressures and evade therapeutic interventions by transitioning between distinct cellular states. However, the contribution of phenotypic plasticity to adaptive drug resistance in glioblastoma (GBM), one of the most lethal of all cancers, remains poorly understood. In this study, we identify that GBM tumor-initiating cells resembling normal radial glia (RG), which occupy the apex of normal neurodevelopment, are driven by aberrant epidermal growth factor receptor (EGFR) signaling. Using a suite of patient-derived GBM models, we demonstrate through global proteomics and single-cell RNA sequencing that pharmacological inhibition of EGFR triggers a lineage transition toward neuronal and oligodendrocyte progenitor (OPC)-like states. This shift is accompanied by activation of oncogenic RAS-MAPK signaling – despite robust and durable inhibition of EGFR activation – and is further modulated by brain microenvironmental cues, including synaptic and calcium-mediated signaling programs. Dual inhibition of EGFR and RAS-MAPK with novel, tumor-selective small molecules blocks these phenotypic transitions and enhances GBM cell death in EGFR-mutated GBM models. To determine the subpopulation dynamics of RAS-MAPK signaling within GBM neurodevelopmental lineages, we develop DENALI (Dual-Expression Nuclear reporter of ERK Activity and Lineage Identity) – a novel, high-complexity barcoded lentiviral vector and integrative fluorescence reporter system. Using DENALI, we investigate the clonal mechanisms driving lineage plasticity in GBM following oncogenic EGFR inhibition and couple adaptive RAS signaling programs to the emergence of neuronal and OPC-like states under EGFRi therapy. Together, our findings establish neurodevelopmental lineage plasticity as a key driver of adaptive resistance in GBM and support dual-inhibition strategies to improve therapeutic outcomes in patients with GBM tumors.

A number of studies have described an essential role of cancer stem cells (CSC) in glioblastoma (GBM) progression and recurrence based on isolation by candidate markers. However, a systematic evaluation of the proposed CSC in paired human primary and recurrent glioblastoma has been lacking and whether they represent a unified cell type with conserved features over tumor evolution is unresolved. In this study, we used human patient derived xenografts (PDX) to investigate the status of these cells in patients following therapeutics and recurrence. Firstly, to ensure the fidelity of tumor heterogeneity in serially passaged orthotopic GBM PDX, we collected samples at different passages and performed whole tumor single cell RNA sequencing analysis. The results illustrate the preservation of all unsupervised transcriptional cell clusters through multiple passages. Furthermore, treatment of tumor bearing mice with temozolomide, the standard of care chemotherapeutic drug for glioblastoma patients, increased apoptosis and decreased tumor cell burden but spared CSC. We then turned to paired human primary and recurrent GBM samples to inquire cancer stem cell marker expression and cell distribution. In all three pairs of PDX studied, cancer stem cell marker F3 serves as a reliable means to isolate sphere formation cells and is augmented in the recurrent samples. Inspection of whole tumors with single cell RNA sequencing nails down the enrichment of CSC in recurrent tumors, thus emphasizing the importance to eradicate these cells in future therapeutics. Citation Format: Xuanhua Peter Xie, Mungunsarnai Ganbold, Alicia Pedraza, Luis Parada. Cancer stem cells are enriched in human recurrent glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB024.

BackgroundGlioma stem-like cells (GSCs) are key drivers of treatment resistance and recurrence in glioblastoma (GBM). Phosphoglycerate dehydrogenase (PHGDH), a crucial enzyme in the de novo serine synthesis pathway (SSP), is implicated in tumorigenesis and therapy resistance across various cancers. However, its specific role in GBM, particularly in radioresistance, remains poorly understood.MethodsIn silico analysis of GBM patient data assessed SSP enrichment and PHGDH expression linked with tumor stemness. Comparative gene expression analysis focused on PHGDH in paired GBM specimens and GSCs. Genetic and pharmacological loss-of-function assays were performed in vitro and in vivo to evaluate PHGDH’s impact on GSC self-renewal and malignant progression. Comprehensive transcriptomic and metabolomic analyses, along with chromatin immunoprecipitation, mass spectrometry, and various other biochemical assays, were used to elucidate PHGDH-mediated mechanisms in GBM progression and radioresistance.ResultsPHGDH expression is significantly elevated in GSCs, associated with aggressive glioma progression and poor clinical outcomes. PHGDH activation enhances GSC self-renewal by regulating redox homeostasis, facilitating one-carbon metabolism, and promoting DNA damage response via SSP activation. Importantly, MYC was identified as a crucial transcriptional regulator of PHGDH expression. Furthermore, genetic ablation or pharmacological inhibition of PHGDH markedly reduced tumor growth and increased tumor sensitivity to radiotherapy, thereby improving survival outcomes in orthotopic GSC-derived and patient-derived GBM xenograft models.ConclusionsThis study underscores the pivotal role of MYC-mediated PHGDH activation in driving GSC malignant progression and radioresistance in GBM. Targeting PHGDH presents a promising approach to enhance radiotherapy efficacy in GBM patients.

Drug resistance is a major challenge in the treatment of tumor diseases, especially in glioblastoma (GBM), where temozolomide (TMZ) plays a critical role. However, the development of resistance to TMZ occurs rapidly in more than half of the patients who initially respond to the drug. This highlights the need for novel approaches to overcome drug resistance and improve therapeutic outcomes in GBM treatment. In our study, we combine TMZ treatment with wireless optoelectronics using advanced multilayered organic semiconductor (MOS) devices. These devices consist of a 200nm thick stack of metal and p-n semiconducting organic nanocrystals. When illuminated in physiological solutions, these MOS devices charge up and convert light pulses into localized displacement currents, which are strong enough to electrically stimulate tumor cells at safe light intensities. Importantly, the freestanding MOS devices require no external wiring or bias and remain stable under physiological conditions. The semiconductor layers are created from common, non-toxic pigments using simple, scalable deposition methods. Our results demonstrate that this combination of TMZ and optoelectronic stimulation significantly enhances apoptosis in tumor cells, thereby improving the effectiveness of TMZ in treating glioblastoma. his research suggests that the integration of wireless optoelectronic stimulation with TMZ treatment offers a promising strategy to overcome drug resistance in GBM. The use of MOS devices enhances the therapeutic effect of TMZ and could lead to better treatment outcomes for patients with glioblastoma.