Pediatric Primitive Neuroectodermal Tumors of the Central Nervous System Differentially Express Granzyme Inhibitors

Immunobiology and Cytokine Modulation of the Pediatric Brain Tumor Microenvironment: A Scoping Review

Utilizing a Scoping Review strategy in the domain of immune biology to identify immune therapeutic targets, knowledge gaps for implementing immune therapeutic strategies for pediatric brain tumors was assessed. The analysis demonstrated limited efforts to date to characterize and understand the immunological aspects of tumor biology with an over-reliance on observations from the adult glioma population. Foundational knowledge regarding the frequency and ubiquity of immune therapeutic targets is an area of unmet need along with the development of immune-competent pediatric tumor models to test therapeutics and especially combinatorial treatment. Opportunities arise in the evolution of pediatric tumor classification from histological to molecular with targeted immune therapeutics.

Pediatric medulloblastoma express immune checkpoint B7-H3

PURPOSE

Medulloblastomas (MB) are highly malignant brain tumors that predominantly occur in young infants. Immunotherapy to boost the immune system is emerging as a novel promising approach, but is often hampered by inhibitory immune checkpoints. In the present study, we have studied immune checkpoint B7-H3 expression in a tissue cohort of human pediatric MB.

METHODS

Expression of B7-H3 was detected by immunohistochemistry and classified via B7-H3 staining intensity and percentage of B7-H3 positive tumor cells. Subsequently, B7-H3 protein expression was distinguished in MB molecular subtypes and correlated to immune cell infiltrates, patient characteristics, and survival.

RESULTS

B7-H3 protein expression was found in 23 out of 24 (96%) human pediatric MB cases and in 17 out of 24 (71%) MB cases > 25% of tumor cells had any level of B7-H3 expression. B7-H3 protein expression was more frequent on Group-4 MB as compared with other molecular subtypes (p = 0.02). Tumors with high B7-H3 expression showed less influx of γδT cells (p = 0.002) and CD3+ T cells (p = 0.041).

CONCLUSION

Immune checkpoint B7-H3 is differentially expressed by the large majority of pediatric MB. This further warrants the development of novel B7-H3-directed (immuno)therapeutic methods for children with incurable, metastatic, or chemo-resistant MB.

Overview of serpin B9 and its roles in cancer (Review)

Serine proteinase inhibitor B9 (serpin B9) is a member of the serine protease inhibitor superfamily, which is widely found in animals, plants and microorganisms. Serpin B9 has been reported to protect cells from the immune‑killing effect of granzyme B (GrB) released by lymphocytes. In recent years, an increasing number of studies have indicated that serpin B9 is involved in tumour apoptosis, immune evasion, tumorigenesis, progression, metastasis, drug resistance and even in maintaining the stemness of cancer stem cells (CSCs). Moreover, according to clinical studies, serpin B9 has been demonstrated to be significantly associated with the development of precancerous lesions, a poor prognosis and ineffective therapies, suggesting that serpin B9 may be a potential target for cancer treatment and an indicator of cancer diagnosis; thus, it has begun to attract increased attention from scholars. The present review concisely described the structure and biological functions of the serpin superfamily and serpin B9. In addition, related research on serpins in cancer is discussed in order to provide a comprehensive understanding of the role of serpin B9 in cancer, as well as its clinical significance for cancer diagnosis and prognosis.

The Dual Roles of Human γδ T Cells: Anti-Tumor or Tumor-Promoting

γδ T cells are the unique T cell subgroup with their T cell receptors composed of γ chain and δ chain. Unlike αβ T cells, γδ T cells are non-MHC-restricted in recognizing tumor antigens, and therefore defined as innate immune cells. Activated γδ T cells can promote the anti-tumor function of adaptive immune cells. They are considered as a bridge between adaptive immunity and innate immunity. However, several other studies have shown that γδ T cells can also promote tumor progression by inhibiting anti-tumor response. Therefore, γδ T cells may have both anti-tumor and tumor-promoting effects. In order to clarify this contradiction, in this review, we summarized the functions of the main subsets of human γδ T cells in how they exhibit their respective anti-tumor or pro-tumor effects in cancer. Then, we reviewed recent γδ T cell-based anti-tumor immunotherapy. Finally, we summarized the existing problems and prospect of this immunotherapy.

Telomere length correlates with subtelomeric DNA methylation in long-term mindfulness practitioners

Mindfulness and meditation techniques have proven successful for the reduction of stress and improvement in general health. In addition, meditation is linked to longevity and longer telomere length, a proposed biomarker of human aging. Interestingly, DNA methylation changes have been described at specific subtelomeric regions in long-term meditators compared to controls. However, the molecular basis underlying these beneficial effects of meditation on human health still remains unclear. Here we show that DNA methylation levels, measured by the Infinium HumanMethylation450 BeadChip (Illumina) array, at specific subtelomeric regions containing GPR31 and SERPINB9 genes were associated with telomere length in long-term meditators with a strong statistical trend when correcting for multiple testing. Notably, age showed no association with telomere length in the group of long-term meditators. These results may suggest that long-term meditation could be related to epigenetic mechanisms, in particular gene-specific DNA methylation changes at distinct subtelomeric regions.

Utilization of invariant natural killer T cells for gastric cancer treatment

AIM

To evaluate the expression of CD1d and the susceptibility to invariant natural killer T (iNKT) cells in gastric cancer.

METHODS

The expression of CD1d was examined in gastric cancer. The in vitro and in vivo cytotoxic activities of iNKT cells were evaluated against gastric cancer cell lines.

RESULTS

CD1d was expressed in gastric cancer cell lines and primary tumors. iNKT cells have potent in vivo and in vitro anti-tumor activities against CD1d-positve gastric cancer in the presence of α-galactosylceramide. Cisplatin could upregulate CD1d expression in gastric cancer cells and make them more vulnerable to iNKT cell-mediated cytotoxicity.

CONCLUSION

These results justified clinical translation of this iNKT cell-based therapeutics, either used alone or combined with chemotherapy, for the treatment of patients with gastric cancer.

Integrated bioinformatic analysis unveils significant genes and pathways in the pathogenesis of supratentorial primitive neuroectodermal tumor

Purpose

This study aimed to explore significant genes and pathways involved in the pathogenesis of supratentorial primitive neuroectodermal tumor (sPNET).

Materials and methods

Gene expression profile of GSE14295 was downloaded from publicly available Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were screened out in primary sPNET samples compared with normal fetal and adult brain reference samples (sPNET vs fetal brain and sPNET vs adult brain). Pathway enrichment analysis of these DEGs was conducted, followed by protein–protein interaction (PPI) network construction and significant module selection. Additionally, transcription factors (TFs) regulating the common DEGs in the two comparison groups were identified, and the regulatory network was constructed.

Results

In total, 526 DEGs (99 up- and 427 downregulated) in sPNET vs fetal brain and 815 DEGs (200 up- and 615 downregulated) in sPNET vs adult brain were identified. DEGs in sPNET vs fetal brain and sPNET vs adult brain were associated with calcium signaling pathway, cell cycle, and p53 signaling pathway. CDK1, CDC20, BUB1B, and BUB1 were hub nodes in the PPI networks of DEGs in sPNET vs fetal brain and sPNET vs adult brain. Significant modules were extracted from the PPI networks. In addition, 64 upregulated and 200 downregulated overlapping DEGs were identified in both sPNET vs fetal brain and sPNET vs adult brain. The genes involved in the regulatory network upon overlapping DEGs and the TFs were correlated with calcium signaling pathway.

Conclusion

Calcium signaling pathway and several genes (CDK1, CDC20, BUB1B, and BUB1) may play important roles in the pathogenesis of sPNET.

Prognostic relevance of tumor-infiltrating lymphocytes and immune checkpoints in pediatric medulloblastoma

Pediatric medulloblastomas are the most frequently diagnosed embryonal tumors of the central nervous system. Current therapies cause severe neurological and cognitive side effects including secondary malignancies. Cellular immunotherapy might be key to improve survival and to avoid morbidity. Efficient killing of tumor cells using immunotherapy requires to overcome cancer-associated strategies to evade cytotoxic immune responses. Here, we examined the immune response and immune evasion strategies in pediatric medulloblastomas. Cytotoxic T-cells, infiltrating medulloblastomas with variable activation status, showed no correlation with overall survival of the patients. We found limited numbers of PD1⁺ T-cells and complete absence of PD-L1 on medulloblastomas. Medulloblastomas downregulated immune recognition molecules MHC-I and CD1 d. Intriguingly, expression of granzyme inhibitors SERPINB1 and SERPINB4 was acquired in 23% and 50% of the tumors, respectively. Concluding, pediatric medulloblastomas exploit multiple immune evasion strategies to overcome immune surveillance. Absence of PD-L1 expression in medulloblastoma suggest limited or no added value for immunotherapy with PD1/PD-L1 blockers.

Brain Cancer Stem Cells in Adults and Children: Cell Biology and Therapeutic Implications

Brain tumors represent some of the most malignant cancers in both children and adults. Current treatment options target the majority of tumor cells but do not adequately target self-renewing cancer stem cells (CSCs). CSCs have been reported to resist the most aggressive radiation and chemotherapies, and give rise to recurrent, treatment-resistant secondary malignancies. With advancing technologies, we now have a better understanding of the genetic, epigenetic and molecular signatures and microenvironmental influences which are useful in distinguishing between distinctly different tumor subtypes. As a result, efforts are now underway to identify and target CSCs within various tumor subtypes based on this foundation. This review discusses progress in CSC biology as it relates to targeted therapies which may be uniquely different between pediatric and adult brain tumors. Studies to date suggest that pediatric brain tumors may benefit more from genetic and epigenetic targeted therapies, while combination treatments aimed specifically at multiple molecular pathways may be more effective in treating adult brain tumors which seem to have a greater propensity towards microenvironmental interactions. Ultimately, CSC targeting approaches in combination with current clinical therapies have the potential to be more effective owing to their ability to compromise CSCs maintenance and the mechanisms which underlie their highly aggressive and deadly nature.