The Dynamics of Tumor-Infiltrating Myeloid Cell Activation and the Cytokine Expression Profile in a Glioma Resection Site during the Post-Surgical Period in Mice

Tailoring glioblastoma treatment based on longitudinal analysis of post-surgical tumor microenvironment

Glioblastoma (GBM), an incurable primary brain tumor, typically requires surgical intervention followed by chemoradiation; however, recurrences remain fatal. Our previous work demonstrated that a nanomedicine hydrogel (GemC12-LNC) delays recurrence when administered post-surgery. However, tumor debulking also triggers time-dependent immune reactions that promote recurrence at the resection cavity borders. We hypothesized that combining the hydrogel with an immunomodulatory drug could enhance therapeutic outcomes. A thorough characterization of the post-surgical microenvironment (SMe) is crucial to guide combinatorial approaches.In this study, we performed cellular resolution imaging, flow cytometry and spatial hyperplexed immunofluorescence imaging to characterize the SMe in a syngeneic mouse model of tumor resection. Owing to our dynamic approach, we observed transient opening of the blood-brain barrier (BBB) during the first week after surgery. BBB permeability post-surgery was also confirmed in GBM patients. In our murine model, we also observed changes in immune cell morphology and spatial location post-surgery over time in resected animals as well as the accumulation of reactive microglia and anti-inflammatory macrophages in recurrences compared to unresected tumors since the first steps of recurrence growth. Therefore we investigated whether starting a systemic treatment with the SMAC mimetic small molecule (GDC-0152) directly after surgery would be beneficial for enhancing microglial anti-tumoral activity and decreasing the number of anti-inflammatory macrophages around the GemC12-LNC hydrogel-loaded tumor cavity. The immunomodulatory effects of this drug combination was firstly shown in patient-derived tumoroids. Its efficacy was confirmed in vivo by survival analysis and correlated with reversal of the immune profile as well as delayed tumor recurrence.This comprehensive study identified critical time frames and immune cellular targets within the SMe, aiding in the rational design of combination therapies to delay recurrence onset. Our findings suggest that post-surgical systemic injection of GDC-0152 in combination with GemC12-LNC local treatment is a promising and innovative approach for managing GBM recurrence, with potential for future translation to human patient.

Pyk2/FAK Signaling Is Upregulated in Recurrent Glioblastoma Tumors in a C57BL/6/GL261 Glioma Implantation Model

The majority of glioblastomas (GBMs) recur shortly after tumor resection and recurrent tumors differ significantly from newly diagnosed GBMs, phenotypically and genetically. In this study, using a Gl261-C57Bl/6 mouse glioma implantation model, we identified significant upregulation of proline-rich tyrosine kinase Pyk2 and focal adhesion kinase (FAK) phosphorylation levels-pPyk2 (579/580) and pFAK (925)-without significant modifications in total Pyk2 and FAK protein expression in tumors regrown after surgical resection, compared with primary implanted tumors. Previously, we demonstrated that Pyk2 and FAK are involved in the regulation of tumor cell invasion and proliferation and are associated with reduced overall survival. We hypothesized that the use of inhibitors of Pyk2/FAK in the postsurgical period may reduce the growth of recurrent tumors. Using Western blot analysis and confocal immunofluorescence approaches, we demonstrated upregulation of Cyclin D1 and the Ki67 proliferation index in tumors regrown after resection, compared with primary implanted tumors. Treatment with Pyk2/FAK inhibitor PF-562271, administered through oral gavage at 50 mg/kg daily for two weeks beginning 2 days before tumor resection, reversed Pyk2/FAK signaling upregulation in recurrent tumors, reduced tumor volume, and increased animal survival. In conclusion, the use of Pyk2/FAK inhibitors can contribute to a delay in GBM tumor regrowth after surgical resection.

Modeling glioblastoma complexity with organoids for personalized treatments

Glioblastoma (GBM) remains a fatal diagnosis despite the current standard of care of maximal surgical resection, radiation, and temozolomide (TMZ) therapy. One aspect that impedes drug development is the lack of an appropriate model representative of the complexity of patient tumors. Brain organoids derived from cell culture techniques provide a robust, easily manipulatable, and high-throughput model for GBM. In this review, we highlight recent progress in developing GBM organoids (GBOs) with a focus on generating the GBM microenvironment (i.e., stem cells, vasculature, and immune cells) recapitulating human disease. Finally, we also discuss the use of organoids as a screening tool in drug development for GBM.

PCBP2 Reduced Oxidative Stress-Induced Apoptosis in Glioma through cGAS/STING Pathway by METTL3-Mediated m6A Modification

Purpose

The most prevalent primary malignant tumor of CNS is glioma, which has a dismal prognosis. The theory of oxidative stress is one of the important theories in the study of its occurrence and development mechanism. In this study, the impacts of PCBP2 on glioma sufferers and the possible mechanisms were examined.

Methods

Patients with glioma were obtained from May 2017 to July 2018. Quantitative PCR, microarray analysis, western blot analysis, and immunofluorescence were used in this experiment.

Results

PCBP2 mRNA expression level and protein expression in patients with glioma were upregulated compared with paracancerous tissue. OS and DFS of PCBP2 low expression in patients with glioma were higher than those of PCBP2 high expression. PCBP2 promoted the progression and metastasis of glioma. PCBP2 reduced oxidative stress-induced apoptosis of glioma. PCBP2 suppressed the cGAS/STING pathway of glioma. PCBP2 protein interlinked with cGAS and cGAS was one target for PCBP2. METTL3-mediated m6A modification increases PCBP2 stability.

Conclusion

Along the cGAS-STING signal pathway, PCBP2 decreased the apoptosis that oxidative stress-induced glioma caused, which might be a potential target to suppress oxidative stress-induced apoptosis of glioma.