Biomimetic Macrophage Membrane-Camouflaged Nanoparticles Induce Ferroptosis by Promoting Mitochondrial Damage in Glioblastoma.

The increasing understanding of ferroptosis has indicated its role and therapeutic potential in cancer; however, this knowledge has yet to be translated into effective therapies. Glioblastoma (GBM) patients face a bleak prognosis and encounter challenges due to the limited treatment options available. In this study, we conducted a genome-wide CRISPR-Cas9 screening in the presence of a ferroptosis inducer (RSL3) to identify the key driver genes involved in ferroptosis. We identified ALOX15, a key lipoxygenase (LOX), as an essential driver of ferroptosis. Small activating RNA (saRNA) was used to mediate the expression of ALOX15 promoted ferroptosis in GBM cells. We then coated saALOX15-loaded mesoporous polydopamine (MPDA) with Angiopep-2-modified macrophage membranes (MMs) to reduce the clearance by the mononuclear phagocyte system (MPS) and increase the ability of the complex to cross the blood-brain barrier (BBB) during specific targeted therapy of orthotopic GBM. These generated hybrid nanoparticles (NPs) induced ferroptosis by mediating mitochondrial dysfunction and rendering mitochondrial morphology abnormal. In vivo, the modified MM enabled the NPs to target GBM cells, exert a marked inhibitory effect on GBM progression, and promote GBM radiosensitivity. Our results reveal ALOX15 to be a promising therapeutic target in GBM and suggest a biomimetic strategy that depends on the biological properties of MMs to enhance the in vivo performance of NPs for treating GBM.

Engineered Extracellular Vesicle-Delivered CRISPR/Cas9 for Radiotherapy Sensitization of Glioblastoma.

Radiotherapy is a mainstay of glioblastoma (GBM) treatment; however, the development of therapeutic resistance has hampered the efficacy of radiotherapy, suggesting that additional treatment strategies are needed. Here, an in vivo loss-of-function genome-wide CRISPR screen was carried out in orthotopic tumors in mice subjected to radiation treatment to identify synthetic lethal genes associated with radiotherapy. Using functional screening and transcriptome analyses, glutathione synthetase (GSS) was found to be a potential regulator of radioresistance through ferroptosis. High GSS levels were closely related to poor prognosis and relapse in patients with glioma. Mechanistic studies demonstrated that GSS was associated with the suppression of radiotherapy-induced ferroptosis in glioma cells. The depletion of GSS resulted in the disruption of glutathione (GSH) synthesis, thereby causing the inactivation of GPX4 and iron accumulation, thus enhancing the induction of ferroptosis upon radiotherapy treatment. Moreover, to overcome the obstacles to broad therapeutic translation of CRISPR editing, we report a previously unidentified genome editing delivery system, in which Cas9 protein/sgRNA complex was loaded into Angiopep-2 (Ang) and the trans-activator of the transcription (TAT) peptide dual-modified extracellular vesicle (EV), which not only targeted the blood-brain barrier (BBB) and GBM but also permeated the BBB and penetrated the tumor. Our encapsulating EVs showed encouraging signs of GBM tissue targeting, which resulted in high GSS gene editing efficiency in GBM (up to 67.2%) with negligible off-target gene editing. These results demonstrate that a combination of unbiased genetic screens, and CRISPR-Cas9-based gene therapy is feasible for identifying potential synthetic lethal genes and, by extension, therapeutic targets.

Rac GTPase activating protein 1 promotes the glioma growth by regulating the expression of MCM3.

Glioma is the most common tumor of the nervous system. The diffuse growth and proliferation of glioma poses great challenges for its treatment. Here, Transcriptomic analysis revealed that Rac GTPase activating protein 1 (RACGAP1) is highly expressed in glioma. RACGAP1 has been shown to play an important role in the malignant biological progression of a variety of tumors. However, the underlying role and mechanism in glioma remain poorly understood. By using quantitative real-time polymerase chain reaction (qRT-PCR), western blot, immunohistochemistry and Orthotopic mouse xenografts, we confirmed that knockdown of RACGAP1 impeded cell proliferation in glioma and prolonged the survival of orthotopic mice. Interestingly, we also found that inhibiting the expression of RACGAP1 reduced the expression of minichromosome maintenance 3 (MCM3) through RNA-seq and rescue assay, while Yin Yang 1 (YY1) transcriptionally regulated RACGAP1 expression. Furthermore, T7 peptide-decorated exosome (T7-exo) is regard as a promising delivery modality for targeted therapy of glioma, and the T7-siRACGAP1-exo significantly improved the survival time of glioma bearing mice. These results suggested that targeting RACGAP1 may be a potential strategy for glioma therapy.

Exosome-transmitted circCABIN1 promotes temozolomide resistance in glioblastoma via sustaining ErbB downstream signaling.

Although temozolomide (TMZ) provides significant clinical benefit for glioblastoma (GBM), responses are limited by the emergence of acquired resistance. Here, we demonstrate that exosomal circCABIN1 secreted from TMZ-resistant cells was packaged into exosomes and then disseminated TMZ resistance of receipt cells. CircCABIN1 could be cyclized by eukaryotic translation initiation factor 4A3 (EIF4A3) and is highly expressed in GBM tissues and glioma stem cells (GSCs). CircCABIN1 is required for the self-renewal maintenance of GSCs to initiate acquired resistance. Mechanistically, circCABIN1 regulated the expression of olfactomedin-like 3 (OLFML3) by sponging miR-637. Moreover, upregulation of OLFML3 activating the ErbB signaling pathway and ultimately contributing to stemness reprogramming and TMZ resistance. Treatment of GBM orthotopic mice xenografts with engineered exosomes targeting circCABIN1 and OLFML3 provided prominent targetability and had significantly improved antitumor activity of TMZ. In summary, our work proposed a novel mechanism for drug resistance transmission in GBM and provided evidence that engineered exosomes are a promising clinical tool for cancer prevention and therapy.

Chromosome 1q21 gain is an adverse prognostic factor for newly diagnosed multiple myeloma patients treated with bortezomib-based regimens.

Chromosome 1q21 aberration is one of the most common cytogenetic abnormalities in multiple myeloma, and is considered an important prognostic factor. The present study analyzed the clinical relevance and prognostic impact of 1q21 gain in 194 patients with newly diagnosed multiple myeloma treated with bortezomib-based regimens. 1q21 gain was detected in 45.9% (89/194) of patients, and those with 1q21 gain had a worse prognosis. Strikingly, our results showed that excluding the effects of other coinciding genetic anomalies, patients carrying at least four copies of 1q21 had worse survival outcome. Moreover, del(13q) strongly correlates with 1q21 gain, and the coexistence of del(13q) and 1q21 gain plays an important role in reducing PFS and OS times. Therefore, 1q21 gain should be considered a high-risk feature in multiple myeloma patients treated with a bortezomib-based regimen.

Kill two birds with one stone: Engineered exosome-mediated delivery of cholesterol modified YY1-siRNA enhances chemoradiotherapy sensitivity of glioblastoma.

Glioblastoma (GBM) is the most malignant tumor of the central nervous system in adults. Irradiation (IR) and temozolomide (TMZ) play an extremely important role in the treatment of GBM. However, major impediments to effective treatment are postoperative tumor recurrence and acquired resistance to chemoradiotherapy. Our previous studies confirm that Yin Yang 1 (YY1) is highly expressed in GBM, whereby it is associated with cell dedifferentiation, survival, and therapeutic resistance. Targeted delivery of small interfering RNA (siRNA) without blood-brain barrier (BBB) restriction for eradication of GBM represents a promising approach for therapeutic interventions. In this study, we utilize the engineering technology to generate T7 peptide-decorated exosome (T7-exo). T7 is a peptide specifically binding to the transferrin receptor. T7-exo shows excellent packaging and protection of cholesterol-modified Cy3-siYY1 while quickly releasing payloads in a cytoplasmic reductive environment. The engineered exosomes T7-siYY1-exo could deliver more effciently to GBM cells both in vitro and in vivo. Notably, in vitro experiments demonstrate that T7-siYY1-exo can enhance chemoradiotherapy sensitivity and reverse therapeutic resistance. Moreover, T7-siYY1-exo and TMZ/IR exert synergistic anti-GBM effect and significantly improves the survival time of GBM bearing mice. Our findings indicate that T7-siYY1-exo may be a potential approach to reverse the chemoradiotherapy resistance in GBM.

Genome-wide CRISPR screen identified Rad18 as a determinant of doxorubicin sensitivity in osteosarcoma.

BACKGROUND: Osteosarcoma (OS) is a malignant bone tumor mostly occurring in children and adolescents, while chemotherapy resistance often develops and the mechanisms involved remain challenging to be fully investigated. METHODS: Genome-wide CRISPR screening combined with transcriptomic sequencing were used to identify the critical genes of doxorubicin resistance. Analysis of clinical samples and datasets, and in vitro and in vivo experiments (including CCK-8, apoptosis, western blot, qRT-PCR and mouse models) were applied to confirm the function of these genes. The bioinformatics and IP-MS assays were utilized to further verify the downstream pathway. RGD peptide-directed and exosome-delivered siRNA were developed for the novel therapy strategy. RESULTS: We identified that E3 ubiquitin-protein ligase Rad18 (Rad18) contributed to doxorubicin-resistance in OS. Further exploration revealed that Rad18 interact with meiotic recombination 11 (MRE11) to promote the formation of the MRE11-RAD50-NBS1 (MRN) complex, facilitating the activation of the homologous recombination (HR) pathway, which ultimately mediated DNA damage tolerance and leaded to a poor prognosis and chemotherapy response in patients with OS. Rad18-knockout effectively restored the chemotherapy response in vitro and in vivo. Also, RGD-exosome loading chemically modified siRad18 combined with doxorubicin, where exosome and chemical modification guaranteed the stability of siRad18 and the RGD peptide provided prominent targetability, had significantly improved antitumor activity of doxorubicin. CONCLUSIONS: Collectively, our study identifies Rad18 as a driver of OS doxorubicin resistance that promotes the HR pathway and indicates that targeting Rad18 is an effective approach to overcome chemotherapy resistance in OS.