Mingchen Yu

Patients with high ALDH1A3-expressing glioblastoma (ALDH1A3hi GBM) show limited benefit from postoperative chemoradiotherapy. Understanding the mechanisms underlying such resistance in these patients is crucial for the development of new treatments. Here, we show that the interaction between ALDH1A3 and PKM2 enhances the latter’s tetramerization and promotes lactate accumulation in glioblastoma stem cells (GSCs). By scanning the lactylated proteome in lactate-accumulating GSCs, we show that XRCC1 undergoes lactylation at lysine 247 (K247). Lactylated XRCC1 shows a stronger affinity for importin α, allowing for greater nuclear transposition of XRCC1 and enhanced DNA repair. Through high-throughput screening of a small-molecule library, we show that D34-919 potently disrupts the ALDH1A3-PKM2 interaction, preventing the ALDH1A3-mediated enhancement of PKM2 tetramerization. In vitro and in vivo treatment with D34-919 enhanced chemoradiotherapy-induced apoptosis of GBM cells. Together, our findings show that ALDH1A3-mediated PKM2 tetramerization is a potential therapeutic target to improve the response to chemoradiotherapy in ALDH1A3hi GBM.

The synthesis and structure-activity relationship studies of novel indole derivatives as peroxisome proliferator-activated receptor (PPAR) agonists are reported. Indole, a drug-like scaffold, was studied as a core skeleton for the acidic head part of PPAR agonists. The structural features (acidic head, substitution on indole, and linker) were optimized first, by keeping benzisoxazole as the tail part, based on binding and functional activity at PPARgamma protein. The variations in the tail part, by introducing various heteroaromatic ring systems, were then studied. In vitro evaluation led to identification of a novel series of indole compounds with a benzisoxazole tail as potent PPAR agonists with the lead compound 14 (BPR1H036) displaying an excellent pharmacokinetic profile in BALB/c mice and an efficacious glucose lowering activity in KKA(y) mice. Structural biology studies of 14 showed that the indole ring contributes strong hydrophobic interactions with PPARgamma and could be an important moiety for the binding to the protein.

BACKGROUND: Glioblastoma is a paradigm of cancer-associated immunosuppression, limiting the effects of immunotherapeutic strategies. Thus, identifying the molecular mechanisms underlying immune surveillance evasion is critical. Recently, the preferential expression of inhibitory natural killer (NK) cell receptor CD161 on glioma-infiltrating cytotoxic T cells was identified. Focusing on the molecularly annotated, large-scale clinical samples from different ethnic origins, the data presented here provide evidence of this immune modulator's essential roles in brain tumor biology. METHODS: Retrospective RNA-seq data analysis was conducted in a cohort of 313 patients with glioma in the Chinese Glioma Genome Atlas (CGGA) database and 603 patients in The Cancer Genome Atlas (TCGA) database. In addition, single-cell sequencing data from seven surgical specimens of glioblastoma patients and a model in which patient-derived glioma stem cells were cocultured with peripheral lymphocytes, were used to analyze the molecular evolution process during gliomagenesis. RESULTS: CD161 was enriched in high-grade gliomas and isocitrate dehydrogenase (IDH)-wildtype glioma. CD161 acted as a potential biomarker for the mesenchymal subtype of glioma and an independent prognostic factor for the overall survival (OS) of patients with glioma. In addition, CD161 played an essential role in inhibiting the cytotoxicity of T cells in glioma patients. During the process of gliomagenesis, the expression of CD161 on different lymphocytes dynamically evolved. CONCLUSION: The expression of CD161 was closely related to the pathology and molecular pathology of glioma. Meanwhile, CD161 promoted the progression and evolution of gliomas through its unique effect on T cell dysfunction. Thus, CD161 is a promising novel target for immunotherapeutic strategies in glioma treatment.

Chimeric antigen receptor (CAR) T-cell therapy has demonstrated clinical response in treating both hematologic malignancies and solid tumors. Although instances of rapid tumor remissions have been observed in animal models and clinical trials, tumor relapses occur with multiple therapeutic resistance mechanisms. Furthermore, while the mechanisms underlying the long-term therapeutic resistance are well-known, short-term adaptation remains less understood. However, more views shed light on short-term adaptation and hold that it provides an opportunity window for long-term resistance. In this study, we explore a previously unreported mechanism in which tumor cells employ trogocytosis to acquire CAR molecules from CAR-T cells, a reversal of previously documented processes. This mechanism results in the depletion of CAR molecules and subsequent CAR-T cell dysfunction, also leading to short-term antigen loss and antigen masking. Such type of intercellular communication is independent of CAR downstream signaling, CAR-T cell condition, target antigen, and tumor cell type. However, it is mainly dependent on antigen density and CAR sensitivity, and is associated with tumor cell cholesterol metabolism. Partial mitigation of this trogocytosis-induced CAR molecule transfer can be achieved by adaptively administering CAR-T cells with antigen density-individualized CAR sensitivities. Together, our study reveals a dynamic process of CAR molecule transfer and refining the framework of clinical CAR-T therapy for solid tumors.

Triggering receptor expressed on myeloid cells 2 (TREM2) is expressed in myeloid cells of the central nervous system (CNS), which mediate the immunological response in a variety of diseases. Uncertain is the function of TREM2 in glioma and tumor immune responses. In this research, the expression patterns of TREM2 in glioma were analyzed, along with its prognostic value and functional roles. TREM2 expression is increased in glioblastomas, gliomas with a mesenchymal subtype, gliomas with wild-type isocitrate dehydrogenase, and gliomas without 1p/19q deletion, all of which suggest the aggressiveness and poor prognosis of gliomas. Gene ontology, KEGG, and Gene set variation analyses indicated that TREM2 may serve as an immune response mediator. However, the function of T cells against tumor cells was negatively correlated with TREM2, suggesting that TREM2 may suppress tumor immunity. Further investigation demonstrated a correlation between TREM2 expression and immune checkpoint expression. CIBERSORT research revealed a link between a higher TREM2 expression level and the enrichment of tumor-associated macrophages, especially M2 subtype. Single-cell analysis and multiple immunohistochemical staining results showed that microglia and macrophage cells expressed TREM2. Immunofluorescent staining indicated that knocking down the expression of TREM2 would result in a decrease in M2 polarization. TREM2 was discovered to be an independent prognostic factor in glioma. In conclusion, our findings revealed that TREM2 was significantly expressed in microglia and macrophage cells and was intimately associated with the tumor immune microenvironment. Thus, it is expected that small-molecule medications targeting TREM2 or monoclonal antibodies would enhance the efficacy of glioma immunotherapy.