Radiosensitization Of Glioblastoma Research Articles

Stimuli-Responsive Peptide/siRNA Nanoparticles as a Radiation Sensitizer for Glioblastoma Treatment by Co-Inhibiting RELA/P65 and EGFR.

To develop a novel approach for increasing radiosensitivity in glioblastoma (GBM) by using targeted nanoparticles to deliver siRNA aimed at silencing the EGFR and RELA/P65 genes, which are implicated in radioresistance. We engineered biodegradable, tumor-targeted, self-assembled, and stimuli-responsive peptide nanoparticles for efficient siRNA delivery. We evaluated the nanoparticles' ability to induce gene silencing and enhance DNA damage under radiation in vitro and in vivo. The nanoparticles were designed to exhibit pH-responsive endosomal escape and αvβ3 integrin targeting, allowing for preferential accumulation at tumor sites and traversal of the blood-brain tumor barrier. The application of these nanoparticles resulted in significant gene silencing, increased apoptosis, and decreased cell viability. The treatment impaired DNA repair mechanisms, thereby enhancing radiosensitivity in GBM cells. In a GBM mouse model, the combination of nanoparticle treatment with radiotherapy notably prolonged survival without apparent toxicity. Our findings suggest that nanoparticle-mediated dual gene silencing can effectively overcome GBM radioresistance. This strategy has the potential to improve clinical outcomes in GBM treatment, proposing a promising therapeutic avenue for this challenging malignancy.

Nanoradiosensitizers in glioblastoma treatment: recent advances and future perspectives.

Glioblastoma (GBM), a highly invasive type of brain tumor located within the central nervous system, manifests a median survival time of merely 14.6months. Radiotherapy kills tumor cells through focused high-energy radiation and has become a crucial treatment strategy for GBM, especially in cases where surgical resection is not viable. However, the presence of radioresistant tumor cells limits its clinical effectiveness. Radioresistance is a key factor of treatment failure, prompting the development of various therapeutic strategies to overcome this challenge. With the rapid development of nanomedicine, nanoradiosensitizers provide a novel approach to enhancing the effectiveness of radiotherapy. In this review, we discuss the reasons behind GBM radio-resistance and the mechanisms of radiotherapy sensitization. Then we summarize the primary types of nanoradiosensitizers and recent progress in their application for the radiosensitization of GBM. Finally, we elucidate the factors influencing their practical implementation, along with the challenges and promising prospects associated with multifunctional nanoradiosensitizers.

2557: Radiosensitization of glioblastoma by BET (Bromodomain and Extra-Terminal motif) inhibition

2557: Radiosensitization of glioblastoma by BET (Bromodomain and Extra-Terminal motif) inhibition

Gelsolin knockdown confers radiosensitivity to glioblastoma cells.

Radiotherapy (RT) is a cornerstone of the glioblastoma (GBM) treatment. However, the resistance of tumour cells to radiation results in early recurrence. The mechanisms underlying GBM radioresistance remain unclear. Screening for differentially expressed genes (DEGs) related to radiation might be a potential solution to this problem. RT-associated DEGs were screened based on the RNA sequencing of 15 paired primary and recurrent GBMs. The mRNA and protein expression of candidate genes were validated in RNA sequencing of The Chinese Genome Atlas (CGGA) dataset and 18 cases of GBM samples. The relationship between the candidate gene and radiation was confirmed in irradiated GBM cells. The association of candidate gene with clinical characteristics and survival was investigated in the CGGA and TCGA dataset. Biological function and pathway analysis were explored by gene ontology analysis. The association of the candidate gene with radiosensitivity was verified using cell counting Kit-8, comet, and colony formation assays invitro and subcutaneous tumour xenograft experiments invivo. Gelsolin (GSN) was selected for further study. GSN expression was significant elevated in recurrent GBM and up-regulated in irradiated GBM cell lines. High expression of GSN was enriched in malignant phenotype of glioma. Moreover, high expression of GSN was associated with poor prognosis. Further investigation demonstrated that GSN-knockdown (GSN-KD) combined with RT significantly inhibited cell proliferation and enhanced radiosensitivity invivo and invitro. Mechanistically, GSN-KD could lead to more serious DNA damage and promotes apoptosis after RT. Radiation induced up-regulated of GSN. GSN-KD could enhance the radiosensitivity of GBM.

Concurrent Olaparib and Radiation Therapy in Older Patients With Newly Diagnosed Glioblastoma: The Phase 1 Dose-Escalation PARADIGM Trial

Background: Patients with glioblastoma who are elderly or have poor performance status (PS) experience particularly poor clinical outcomes. At the time of study initiation, these patients were treated with short-course radiotherapy (40 Gy in 15 fractions). Olaparib is an oral inhibitor of the DNA repair enzyme poly(ADP-ribose) polymerase (PARP) that is well tolerated as a single agent but exacerbates acute radiation toxicity in extracranial sites. Preclinical data predicted that PARP inhibitors would enhance radiosensitivity in glioblastoma without exacerbating adverse effects on the normal brain. Methods: Phase I of the PARADIGM trial was a 3+3 dose escalation study testing olaparib in combination with radiotherapy (40 Gy 15 fractions) in patients with newly diagnosed glioblastoma who were unsuitable for radical treatment either because they were aged 70 or over (WHO PS 0-1) or aged 18-69 with PS 2. The primary outcome was the recommended phase 2 dose (RP2D) of olaparib. Secondary endpoints included safety and tolerability, overall survival (OS) and progression free survival (PFS). Effects on cognitive function were assessed by mini-mental state examination (MMSE). Results: Of 16 eligible patients (56.25% male, median age 71.5 [range 44-78 years], 75% PS 0-1), one dose-limiting toxicity was reported (grade 3 agitation). Maximum tolerated dose was not reached and the RP2D was determined as 200 mg twice daily. Median OS and PFS were 10.8 months (80% CI: 7.3-11.4) and 5.5 months (80% CI: 3.9-5.9) respectively. MMSE plots indicated that cognitive function was not adversely affected by the olaparib-radiotherapy combination. Conclusions: Olaparib can be safely combined with hypofractionated brain radiotherapy and is well tolerated in patients unsuitable for radical chemoradiation. These results enabled initiation of a randomised phase II study and support future trials of PARP inhibitors in combination with radiotherapy for patients with brain tumors.

Radiosensitization of Glioblastoma Using Targeted Inhibition of N-Myristoylation

Treating Glioblastoma remains a major challenge. Radiotherapy has a long-standing role in extending survival, but almost all tumors are expected to recur and be fatal. Historic dose-escalation studies do not yield additional benefit beyond the current 60 Gy dose. Further therapeutic improvement can be gained with radiosensitizers. An undiscovered potential radiosensitization approach may exist in inhibiting the N-myristoylation pathways upregulated in malignant cells. Inhibiting this pathway has been shown to have pleotropic effects including decreasing PARP-1 activity and other cancer-driving pathways that may synergize with radiotherapy. This is a first report in using a targeted N-myristoyltransferase (NMT) inhibitor as a radiosensitizer in glioblastoma. Immortalized glioma cell lines (U87 and U251) and patient-derived de novo (ED501) and post-chemoradiation recurrent (ED512) cell lines were used to a NMT1/2 inhibitor with radiotherapy. Cell surface expression levels for NMT1 and NMT2 were established using immunofluorescence microscopy. In vitro cell viability studies via mitochondrial reduction of resazurin dye and clonogenic assays were done with single fraction 2 & 4 Gy irradiation with 5 days of drug exposure (5-150 nM 3 days prior to irradiation and 2 days post) to account for drug pharmacodynamics. PARP-1 expression by western blot was tested with exposure to drug and/or radiation. Whole exome sequencing and methylation profiling were done to find predictive markers of radiosensitization. Preliminary results show significant radiosensitization effect with a dose enhancement factor ranging from 1.33 to 2.71x higher than radiation alone. The amount of radiosensitization varied per cell line, with U251 and ED512 being more sensitive. The cell line sensitivity was not reliably predicted by the NMT cell surface receptor expression. PARP-1 activity increased with radiotherapy but was inhibited with drug exposure. Exome sequencing showed the radiosensitizing effect correlated with mutations in DNA damage repair and myristoylation pathways. N-myristoylation inhibition appears to be a novel method of radiosensitization for glioblastoma. N-myristoylation affects multiple oncogenic pathways including PARP-1 downregulation, which impedes DNA damage repair and may be what leads to radiosensitization. Future studies are aimed at further predictive markers and in vivo efficacy.

IKBKE Promotes Radioresistance of Glioblastoma through AKT/FOXO3a Pathway

Glioblastoma is an intracranial highly malignant primary tumor, and postoperative radiotherapy is a common treatment of glioblastoma. While radiotherapy resistance of glioblastoma is an important reason for treatment failure. IKBKE is overexpressed in gliomas, but its role in radiotherapy is unknown. This study confirmed that IKBKE can directly phosphorylate AKT protein to regulate FOXO3a, thus promoting the radioresistance of glioblastoma, and proposed a new therapeutic strategy to enhance the efficacy of radiotherapy. We used flow cytometry, tunel staining, plate cloning, a cell counting kit and WB to confirm the effects of IKBKE and FOXO3a on radioresistance of glioblastoma, and immunofluorescence and WB were used to detect the expression of γ-H2AX. Subcutaneous tumor formation in mice and immunohistochemical staining was performed. IP combined with mass spectrometry, immunofluorescence, endogenous and exogenous IP were used to confirm the interaction between IKBKE and AKT. Point mutation, IP and WB were used to confirm the phosphorylation site of AKT. IP and some small molecule inhibitors were used to confirm the relationship between IKBKE, AKT and PI3K. The effect of IKBKE on FOXO3a was confirmed by WB and qPCR. The protein relationship among IKBKE, FOXO3a and 14-3-3 was confirmed by CHX, MG132, ubiquitin test, immunofluorescence and IP. The above experiments were carried out to verify the effect of Amlexanox, an IKBKE inhibitor, on glioblastoma. And its pharmacokinetics in the brain was determined by LC-MS to provide a theoretical basis for further clinical use. It was found that IKBKE could increase the radioresistance of glioblastoma in vitro and in vivo. IKBKE could directly phosphorylate AKT, and its phosphorylation sites were Ser473 and Thr308. We also certified that IKBKE activated AKT independent of PI3K. IKBKE inhibited the expression of FOXO3a on protein level, promoted its ubiquitin degradation, enhanced its interaction with 14-3-3, and inhibited its transportation into the nucleus. FOXO3a can increase the radiosensitivity of glioblastoma. Amlexanox, an IKBKE inhibitor, can inhibit the radiosensitivity of glioblastoma and partially pass through the blood-brain barrier to enhance the radiosensitivity of intracranial tumors. IKBKE can activate AKT independent of PI3K by directly phosphorylating AKT Ser473 and Thr308, thus increasing the phosphorylation of FOXO3a. Phosphorylated FOXO3a promoted its ubiquitin degradation, and inhibited its transportation into the nucleus, causing radioresistance in glioblastoma. IKBKE inhibitor Amlexanox can pass through the blood-brain barrier and increase the radiosensitivity of intracranial tumor cells.

98 Radiosensitization of Glioblastoma Using Targeted Inhibition of N-Myristoylation

98 Radiosensitization of Glioblastoma Using Targeted Inhibition of N-Myristoylation

Multiomics analyses reveal DARS1-AS1/YBX1-controlled posttranscriptional circuits promoting glioblastoma tumorigenesis/radioresistance.

The glioblastoma (GBM) stem cell-like cells (GSCs) are critical for tumorigenesis/therapeutic resistance of GBM. Mounting evidence supports tumor-promoting function of long noncoding RNAs (lncRNAs), but their role in GSCs remains poorly understood. By combining CRISPRi screen with orthogonal multiomics approaches, we identified a lncRNA DARS1-AS1-controlled posttranscriptional circuitry that promoted the malignant properties of GBM cells/GSCs. Depleting DARS1-AS1 inhibited the proliferation of GBM cells/GSCs and self-renewal of GSCs, prolonging survival in orthotopic GBM models. DARS1-AS1 depletion also impaired the homologous recombination (HR)-mediated double-strand break (DSB) repair and enhanced the radiosensitivity of GBM cells/GSCs. Mechanistically, DARS1-AS1 interacted with YBX1 to promote target mRNA binding and stabilization, forming a mixed transcriptional/posttranscriptional feed-forward loop to up-regulate expression of the key regulators of G1-S transition, including E2F1 and CCND1. DARS1-AS1/YBX1 also stabilized the mRNA of FOXM1, a master transcription factor regulating GSC self-renewal and DSB repair. Our findings suggest DARS1-AS1/YBX1 axis as a potential therapeutic target for sensitizing GBM to radiation/HR deficiency-targeted therapy.

Concurrent Activation of Both Survival-Promoting and Death-Inducing Signaling by Chloroquine in Glioblastoma Stem Cells: Implications for Potential Risks and Benefits of Using Chloroquine as Radiosensitizer.

Lysosomotropic agent chloroquine was shown to sensitize non-stem glioblastoma cells to radiation in vitro with p53-dependent apoptosis implicated as one of the underlying mechanisms. The in vivo outcomes of chloroquine or its effects on glioblastoma stem cells have not been previously addressed. This study undertakes a combinatorial approach encompassing in vitro, in vivo and in silico investigations to address the relationship between chloroquine-mediated radiosensitization and p53 status in glioblastoma stem cells. Our findings reveal that chloroquine elicits antagonistic impacts on signaling pathways involved in the regulation of cell fate via both transcription-dependent and transcription-independent mechanisms. Evidence is provided that transcriptional impacts of chloroquine are primarily determined by p53 with chloroquine-mediated activation of pro-survival mevalonate and p21-DREAM pathways being the dominant response in the background of wild type p53. Non-transcriptional effects of chloroquine are conserved and converge on key cell fate regulators ATM, HIPK2 and AKT in glioblastoma stem cells irrespective of their p53 status. Our findings indicate that pro-survival responses elicited by chloroquine predominate in the context of wild type p53 and are diminished in cells with transcriptionally impaired p53. We conclude that p53 is an important determinant of the balance between pro-survival and pro-death impacts of chloroquine and propose that p53 functional status should be taken into consideration when evaluating the efficacy of glioblastoma radiosensitization by chloroquine.

Selective Inhibition of PI3K Isoforms in Brain Tumors Suppresses Tumor Growth by Increasing Radiosensitivity.

Glioblastoma (GBM) is a malignant brain tumor with poor prognosis. Radioresistance is a major challenge in the treatment of brain tumors. The development of several types of tumors, including GBM, involves the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. Upon activation, this pathway induces radioresistance. In this study, we investigated whether additional use of selective inhibitors of PI3K isoforms would enhance radiosensitivity in GBM. We evaluated whether radiation combined with PI3K isoform selective inhibitors can suppress radioresistance in GBM. Glioma 261 expressing luciferase (GL261-luc) and LN229 were used to confirm the effect of combination of radiation and PI3K isoform inhibitors in vitro. Cell viability was confirmed by clonogenic assay, and inhibition of PI3K/AKT signaling activation was observed by Western blot. To confirm radiosensitivity, the expression of phospho-γ-H2AX was observed by immunofluorescence. In addition, to identify the effect of a combination of radiation and PI3K-α isoform inhibitor in vivo, an intracranial mouse model was established by implanting GL261-luc. Tumor growth was observed by IVIS imaging, and survival was analyzed using Kaplan-Meier survival curves. Suppression of the PI3K/AKT signaling pathway increased radiosensitivity, and PI3K-α inhibition had similar effects on PI3K-pan inhibition in vitro. The combination of radiotherapy and PI3K-α isoform inhibitor suppressed tumor growth and extended survival in vivo. This study verified that PI3K-α isoform inhibition improves radiosensitivity, resulting in tumor growth suppression and extended survival in GBM mice.

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.

An Orthotopic Model of Glioblastoma Is Resistant to Radiodynamic Therapy with 5-AminoLevulinic Acid.

Simple SummaryRadiosensitization of glioblastoma is a major ambition to increase the survival of this incurable cancer. Before surgery, oral administration of 5-aminolevulinic acid leads to the accumulation of fluorescent protoporphyrin IX, preferentially in the cancer cells rather than in the normal brain. This property is used to optimize the resection of the tumor under fluorescent light. Protoporphyrin IX may also carry radiosensitization activity. To test this hypothesis, we designed a robust murine preclinical model of glioblastoma with tumors implanted into the brain of mice treated by fractionated radiotherapy, as for humans. Despite the specific accumulation of porphyrins in glioblastoma, there was no radiosensitization. We confirmed these results in in vitro 3D patient-derived spheroids. Radiosensitization by molecules such as porphyrins needs more exploration for application in glioblastoma treatment.Radiosensitization of glioblastoma is a major ambition to increase the survival of this incurable cancer. The 5-aminolevulinic acid (5-ALA) is metabolized by the heme biosynthesis pathway. 5-ALA overload leads to the accumulation of the intermediate fluorescent metabolite protoporphyrin IX (PpIX) with a radiosensitization potential, never tested in a relevant model of glioblastoma. We used a patient-derived tumor cell line grafted orthotopically to create a brain tumor model. We evaluated tumor growth and tumor burden after different regimens of encephalic multifractionated radiation therapy with or without 5-ALA. A fractionation scheme of 5 × 2 Gy three times a week resulted in intermediate survival [48–62 days] compared to 0 Gy (15–24 days), 3 × 2 Gy (41–47 days) and, 5 × 3 Gy (73–83 days). Survival was correlated to tumor growth. Tumor growth and survival were similar after 5 × 2 Gy irradiations, regardless of 5-ALA treatment (RT group (53–67 days), RT+5-ALA group (40–74 days), HR = 1.57, p = 0.24). Spheroid growth and survival were diminished by radiotherapy in vitro, unchanged by 5-ALA pre-treatment, confirming the in vivo results. The analysis of two additional stem-like patient-derived cell lines confirmed the absence of radiosensitization by 5-ALA. Our study shows for the first time that in a preclinical tumor model relevant to human glioblastoma, treated as in clinical routine, 5-ALA administration, although leading to important accumulation of PpIX, does not potentiate radiotherapy.

SDC1-dependent TGM2 determines radiosensitivity in glioblastoma by coordinating EPG5-mediated fusion of autophagosomes with lysosomes

ABSTRACT Glioblastoma multiforme (GBM) is the most common brain malignancy insensitive to radiotherapy (RT). Although macroautophagy/autophagy was reported to be a fundamental factor prolonging the survival of tumors under radiotherapeutic stress, the autophagic biomarkers coordinated to radioresistance of GBM are still lacking in clinical practice. Here we established radioresistant GBM cells and identified their protein profiles using tandem mass tag (TMT) quantitative proteomic analysis. It was found that SDC1 and TGM2 proteins were overexpressed in radioresistant GBM cells and tissues and they contributed to the poor prognosis of RT. Knocking down SDC1 and TGM2 inhibited the fusion of autophagosomes with lysosomes and thus enhanced the radiosensitivity of GBM cells. After irradiation, TGM2 bound with SDC1 and transported it from the cell membrane to lysosomes, and then bound to LC3 through its two LC3-interacting regions (LIRs), coordinating the encounter between autophagosomes and lysosomes, which should be a prerequisite for lysosomal EPG5 to recognize LC3 and subsequently stabilize the STX17-SNAP29-VAMP8 QabcR SNARE complex assembly. Moreover, when combined with RT, cystamine dihydrochloride (a TGM2 inhibitor) extended the lifespan of GBM-bearing mice. Overall, our findings demonstrated the EPG5 tethering mode with SDC1 and TGM2 during the fusion of autophagosomes with lysosomes, providing new insights into the molecular mechanism and therapeutic target underlying radioresistant GBM.Abbreviations: BafA1: bafilomycin A1; CQ: chloroquine; Cys-D: cystamine dihydrochloride; EPG5: ectopic P-granules 5 autophagy tethering factor; GBM: glioblastoma multiforme; GFP: green fluorescent protein; LAMP2: lysosomal associated membrane protein 2; LIRs: LC3-interacting regions; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NC: negative control; RFP: red fluorescent protein; RT: radiotherapy; SDC1: syndecan 1; SNAP29: synaptosome associated protein 29; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TGM2: transglutaminase 2; TMT: tandem mass tag; VAMP8: vesicle associated membrane protein 8; WT: wild type

Circ_0060055 Promotes the Growth, Invasion, and Radioresistance of Glioblastoma by Targeting MiR-197-3p/API5 Axis.

Circular RNA (circRNA) has been shown to be involved in the regulation of human disease progression. Our study aims to reveal the role of circ_0060055 in the progression of glioblastoma (GBM) and its potential molecular mechanism. The expression of circ_0060055, microRNA (miR)-197-3p, and apoptosis inhibitor 5 (API5) was determined by quantitative real-time PCR. GBM cell proliferation, apoptosis, and invasion were assessed using cell counting kit 8 assay, colony formation assay, EdU assay, flow cytometry, and transwell assay. Besides, the radiosensitivity of cells also was assessed using colony formation assay. The interaction between miR-197-3p and circ_0060055 or API5 was analyzed by dual-luciferase reporter assay and RNA pull-down assay. Animal experiments were conducted to measure the effect of circ_0060055 on GBM tumor growth and radiosensitivity in vivo. Circ_0060055 was overexpressed in GBM tumor tissues and cells, and its silencing suppressed GBM cell proliferation and invasion, while promoted apoptosis and radiosensitivity. In terms of mechanism, circ_0060055 could interact with miR-197-3p, and miR-197-3p could target API5. API5 expression also could be positively regulated by circ_0060055. Function experiments suggested that miR-197-3p inhibitor abolished the effect of circ_0060055 knockdown on GBM cell growth, invasion, and radiosensitivity. MiR-197-3p repressed GBM cell progression and improved radiosensitivity, and this effect was eliminated by API5 upregulation. In vivo experiments confirmed that circ_0060055 knockdown reduced GBM tumor growth and enhanced the radiosensitivity of tumors. This study revealed that circ_0060055 contributed to GBM progression and radioresistance through miR-197-3p/API5 pathway, providing a potential target for GBM treatment.

TRIM56 Reduces Radiosensitization of Human Glioblastoma by Regulating FOXM1-Mediated DNA Repair.

Recurrent glioblastoma is characterized by resistance to radiotherapy or chemotherapy. In this study, we investigated the role of TRIM56 in radiosensitization and its potential underlying molecular mechanism. TRIM56 expression levels were measured in glioblastoma tissues and cell lines by immunohistochemical staining, western blot, and qRT-PCR. MTT assay, colony formation assay, and TUNEL assay were used to investigate the effect of TRIM56 on cell viability, cell proliferation, and cell apoptosis. Co-immunoprecipitation was used to clarify the interaction between TRIM56 and FOXM1. Finally, tumor xenograft experiments were performed to analyze the effect of TRIM56 on tumor growth in vivo. The expression of TRIM56 was significantly increased in glioblastoma tissues and cell lines and its expression was associated with poor prognosis of patients with glioblastoma. Moreover, TRIM56 reduced the radiosensitivity of glioblastoma cells and promoted DNA repairment. Mechanistically, TRIM56 promoted FOXM1 protein level, enhanced the stability of FOXM1 by de-ubiquitination, and promoted DNA damage repair through FOXM1 in glioblastoma cells. TRIM56 could reduce the radiosensitivity of glioblastoma in vivo. TRIM56 may suppress the radiosensitization of human glioblastoma by regulating FOXM1-mediated DNA repair. Targeting the TRIM56 may be an effective method to reverse radiotherapy-resistant in glioblastoma recurrent.

Interaction of curcumin with glioblastoma cells via high and low linear energy transfer radiation therapy inducing radiosensitization effects

Glioblastoma is a deadly cancer tumor in the brain and has a survival rate of about 15 months. Despite the high mortality rate, temozolomide has proven to increase the survival rate of patients when combined with radiotherapy. However, its effects may be limited because some patients develop therapeutic resistance. Curcumin has proven to be a cancer treatment due to its broad anticancer spectrum, high efficiency and low toxic level. Additionally, curcumin significantly enhanced radiation efficacy under high and low Linear Energy Transfer (LET) radiation conditions in vitro. In combination with radiation, curcumin increased the cell population in the sub-G1 phase and the reactive oxygen species (ROS) level, ultimately increasing GBM cellular apoptosis. The radiosensitizing effects of curcumin are much higher in neutron (high LET)-irradiated cell lines than in γ (low LET)-irradiated cell lines. Curcumin plus neutron combination significantly inhibited cell invasion compared with that of single treatment or curcumin combined γ-ray treatment. Curcumin enhances the radiosensitivity of Glioblastoma (GBM), suggesting it may have clinical utility in combination cancer treatment with neutron high-LET radiation.

Ultrasound-triggered microbubble destruction enhances the radiosensitivity of glioblastoma by inhibiting PGRMC1-mediated autophagy in vitro and in vivo

BackgroundUltrasound-triggered microbubble destruction (UTMD) is a widely used noninvasive technology in both military and civilian medicine, which could enhance radiosensitivity of various tumors. However, little information is available regarding the effects of UTMD on radiotherapy for glioblastoma or the underlying mechanism. This study aimed to delineate the effect of UTMD on the radiosensitivity of glioblastoma and the potential involvement of autophagy.MethodsGL261, U251 cells and orthotopic glioblastoma-bearing mice were treated with ionizing radiation (IR) or IR plus UTMD. Autophagy was observed by confocal microscopy and transmission electron microscopy. Western blotting and immunofluorescence analysis were used to detect progesterone receptor membrane component 1 (PGRMC1), light chain 3 beta 2 (LC3B2) and sequestosome 1 (SQSTM1/p62) levels. Lentiviral vectors or siRNAs transfection, and fluorescent probes staining were used to explore the underlying mechanism.ResultsUTMD enhanced the radiosensitivity of glioblastoma in vitro and in vivo (P < 0.01). UTMD inhibited autophagic flux by disrupting autophagosome-lysosome fusion without impairing lysosomal function or autophagosome synthesis in IR-treated glioblastoma cells. Suppression of autophagy by 3-methyladenine, bafilomycin A1 or ATG5 siRNA had no significant effect on UTMD-induced radiosensitization in glioblastoma cells (P < 0.05). Similar results were found when autophagy was induced by rapamycin or ATG5 overexpression (P > 0.05). Furthermore, UTMD inhibited PGRMC1 expression and binding with LC3B2 in IR-exposed glioblastoma cells (P < 0.01). PGRMC1 inhibitor AG-205 or PGRMC1 siRNA pretreatment enhanced UTMD-induced LC3B2 and p62 accumulation in IR-exposed glioblastoma cells, thereby promoting UTMD-mediated radiosensitization (P < 0.05). Moreover, PGRMC1 overexpression abolished UTMD-caused blockade of autophagic degradation, subsequently inhibiting UTMD-induced radiosensitization of glioblastoma cells. Finally, compared with IR plus UTMD group, PGRMC1 overexpression significantly increased tumor size [(3.8 ± 1.1) mm2 vs. (8.0 ± 1.9) mm2, P < 0.05] and decreased survival time [(67.2 ± 2.6) d vs. (40.0 ± 1.2) d, P = 0.0026] in glioblastoma-bearing mice.ConclusionUTMD enhanced the radiosensitivity of glioblastoma partially by disrupting PGRMC1-mediated autophagy.

DUSP6 regulates radiosensitivity in glioblastoma by modulating the recruitment of phosphorylated DNAPKcs at DNA double-strand breaks.

Glioblastoma (GBM) has poor median survival due to its resistance to chemoradiotherapy, which results in tumor recurrence. Recurrent GBMs currently lack effective treatments. DUSP6 is known to be pro-tumorigenic and is upregulated in GBM. We show that DUSP6 expression is significantly higher in recurrent GBM patient biopsies compared to expression levels in primary GBM biopsies. Importantly, although it has been reported to be a cytoplasmic protein, we found nuclear localization of DUSP6 in primary and recurrent patient samples and in parent and relapse populations of GBM cell lines generated from an in vitro radiation survival model. DUSP6 inhibition using BCI resulted in decreased proliferation and clonogenic survival of parent and relapse cells. Pharmacological or genetic inhibition of DUSP6 catalytic activity radiosensitized primary and, importantly, relapse GBM cells by inhibiting the recruitment of phosphorylated DNAPKcs (also known as PRKDC), subsequently downregulating the recruitment of phosphorylated histone H2AX (γH2AX) and 53BP1 (also known as TP53BP1). This resulted in decreased cell survival and prolonged growth arrest upon irradiation in vitro and significantly increased the progression-free survival in orthotopic mouse models of GBM. Our study highlights a non-canonical function of DUSP6, emphasizing the potential application of DUSP6 inhibitors in the treatment of recurrent GBM.

A functional artificial neural network for noninvasive pretreatment evaluation of glioblastoma patients.

BackgroundPretreatment assessments for glioblastoma (GBM) patients, especially elderly or frail patients, are critical for treatment planning. However, genetic profiling with intracranial biopsy carries a significant risk of permanent morbidity. We previously demonstrated that the CUL2 gene, encoding the scaffold cullin2 protein in the cullin2-RING E3 ligase (CRL2), can predict GBM radiosensitivity and prognosis. CUL2 expression levels are closely regulated with its copy number variations (CNVs). This study aims to develop artificial neural networks (ANNs) for pretreatment evaluation of GBM patients with inputs obtainable without intracranial surgical biopsies.MethodsPublic datasets including Ivy-GAP, The Cancer Genome Atlas Glioblastoma (TCGA-GBM), and the Chinese Glioma Genome Atlas (CGGA) were used for training and testing of the ANNs. T1 images from corresponding cases were studied using automated segmentation for features of heterogeneity and tumor edge contouring. A ratio comparing the surface area of tumor borders versus the total volume (SvV) was derived from the DICOM-SEG conversions of segmented tumors. The edges of these borders were detected using the canny edge detector. Packages including Keras, Pytorch, and TensorFlow were tested to build the ANNs. A 4-layered ANN (8-8-8-2) with a binary output was built with optimal performance after extensive testing.ResultsThe 4-layered deep learning ANN can identify a GBM patient’s overall survival (OS) cohort with 80%–85% accuracy. The ANN requires 4 inputs, including CUL2 copy number, patients’ age at GBM diagnosis, Karnofsky Performance Scale (KPS), and SvV ratio.ConclusionQuantifiable image features can significantly improve the ability of ANNs to identify a GBM patients’ survival cohort. Features such as clinical measures, genetic data, and image data, can be integrated into a single ANN for GBM pretreatment evaluation.