Features and therapeutic potential of T-cell receptors in high-grade glioma

Thymosin α1 modulated the immune landscape of COVID-19 patients revealed by single-cell RNA and TCR sequencing

BACKGROUND

The Coronavirus disease-19 (COVID-19) pandemic has posed a serious threat to global health. Thymosin α1 (Tα1) was considered to be applied in COVID-19 therapy. However, the data remains limited.

METHODS

Participants with or without Tα1 treatment were recruited. Single cell RNA-sequencing (scRNA-seq) and T cell receptor-sequencing (TCR-seq) of the peripheral blood mononuclear cell (PBMC) samples were done to analyze immune features. The differential expression analysis and functional enrichment analysis were performed to explore the mechanism of Tα1 therapy.

RESULTS

33 symptomatic SARS-CoV-2-infected individuals (COV) and 11 healthy controls (HC) were enrolled in this study. The proportion of CD3+ KLRD1+ NKT, TBX21+ CD8+ NKT was observed to increase in COVID-19 patients with Tα1 treatment (COVT) than those without Tα1 (COV) (p = 0.024; p = 0.010). These two clusters were also significantly higher in Health controls with Tα1 treatment (HCT) than those without Tα1 (HC) (p = 0.016; p = 0.031). Besides, a series of genes and pathways related to immune responses were significantly higher enriched in Tα1 groups TBX21+ CD8+ NKT, such as KLRB1, PRF1, natural killer cell-mediated cytotoxicity pathway, chemokine signaling pathway, JAK-STAT signaling pathway. The increased TRBV9-TRBJ1-1 pair existed in both HCs and COVID-19 patients after Tα1 treatment. 1389 common complementarity determining region 3 nucleotides (CDR 3 nt) were found in COV and HC, while 0 CDR 3 nt was common in COVT and HCT.

CONCLUSIONS

Tα1 increased CD3+ KLRD1+ NKT, TBX21+ CD8+ NKT cell proportion and stimulated the diversity of TCR clones in COVT and HCT. And Tα1 could regulate the expression of genes associated with NKT activation or cytotoxicity to promote NKT cells. These data support the use of Tα1 in COVID-19 patients.

The Tumor Immune Microenvironment in Primary CNS Neoplasms: A Review of Current Knowledge and Therapeutic Approaches

Primary CNS neoplasms are responsible for considerable mortality and morbidity, and many therapies directed at primary brain tumors have proven unsuccessful despite their success in preclinical studies. Recently, the tumor immune microenvironment has emerged as a critical aspect of primary CNS neoplasms that may affect their malignancy, prognosis, and response to therapy across patients and tumor grades. This review covers the tumor microenvironment of various primary CNS neoplasms, with a focus on glioblastoma and meningioma. Additionally, current therapeutic strategies based on elements of the tumor microenvironment, including checkpoint inhibitor therapy and immunotherapeutic vaccines, are discussed.

Assessment of circulating tumor DNA in cerebrospinal fluid by whole exome sequencing to detect genomic alterations of glioblastoma

BACKGROUND

Cerebrospinal fluid (CSF) has been demonstrated as a better source of circulating tumor DNA (ctDNA) than plasma for brain tumors. However, it is unclear whether whole exome sequencing (WES) is qualified for detection of ctDNA in CSF. The aim of this study was to determine if assessment of ctDNA in CSF by WES is a feasible approach to detect genomic alterations of glioblastoma.

METHODS

CSFs of ten glioblastoma patients were collected pre-operatively at the Department of Neurosurgery, Sun Yat-sen University Cancer Center. ctDNA in CSF and genome DNA in the resected tumor were extracted and subjected to WES. The identified glioblastoma-associated mutations from ctDNA in CSF and genome DNA in the resected tumor were compared.

RESULTS

Due to the ctDNA in CSF was unqualified for exome sequencing for one patient, nine patients were included into the final analysis. More glioblastoma-associated mutations tended to be detected in CSF compared with the corresponding tumor tissue samples (3.56 ± 0.75 vs. 2.22 ± 0.32, P = 0.097), while the statistical significance was limited by the small sample size. The average mutation frequencies were similar in CSF and tumor tissue samples (74.1% ± 6.0% vs. 73.8% ± 6.0%, P = 0.924). The R132H mutation of isocitrate dehydrogenase 1 and the G34V mutation of H3 histone, family 3A (H3F3A) which had been reported in the pathological diagnoses were also detected from ctDNA in CSF by WES. Patients who received temozolomide chemotherapy previously or those whose tumor involved subventricular zone tended to harbor more mutations in their CSF.

CONCLUSION

Assessment of ctDNA in CSF by WES is a feasible approach to detect genomic alterations of glioblastoma, which may provide useful information for the decision of treatment strategy.

Different T-cell subsets in glioblastoma multiforme and targeted immunotherapy

Glioblastoma multiforme (GBM) is a brain tumor with a high mortality rate. Surgical resection combined with radiotherapy and chemotherapy is the standard treatment for GBM patients, but the 5-year survival rate of patients despite this treatment is low. Immunotherapy has attracted increasing attention in recent years. As the pioneer and the main effector cells of immunotherapy, T cells play a key role in tumor immunotherapy. However, the T cells in GBM microenvironment are inhibited by the highly immunosuppressive environment of GBM, posing huge challenges to T cell-based GBM immunotherapy. This review summarizes the effects of the GBM microenvironment on the infiltration and function of different T-cell subsets and the possible strategies to overcome immunosuppression, and thus enhance the effectiveness of GBM immunotherapy.