Jinling Cui,Shuang Zhao,Hui Chen,Yuhan Fu,Kai Han,Shutao Yin,Chong Zhao,Lihong Fan,Hongbo Hu
Acquired resistance compromises the efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)-based therapy for non-small cell lung cancer (NSCLC), and activation of hepatocyte growth factor receptor (MET) is one of the pivotal strategies for cancer cells to acquire refractory phenotype. However, the mechanisms involved in regulating MET activity remain to be further elucidated. Using gefitinib-resistant HCC827GR cell line as a model, we unraveled that the dysregulated amino acid metabolisms reflected by elevated expression of cysteine-preferring transporter 2 (ASCT2), cystine/glutamate antiporter solute carrier family 7 member 11 (SLC7A11) and asparagine synthetase (ASNS) might contribute to survival advantage of HCC827GR cells, and rendered the cells more sensitive to asparagine (ASN) deprivation compared to parental HCC827 cells. We further identified that the increased ASNS expression is a contributing factor for the activation of MET in HCC827GR cells. More importantly, we found that methylseleninic acid (MSeA), a precursor of methylselenol, effectively suppressed tumor growth in HCC827GR xenograft model, which is associated with decrease of intracellular ASN content along with inactivation of MET- T-lymphokine-activated killer cell-originated protein kinase (TOPK) signaling axis. Finally, we demonstrated that combination of MSeA and gefitinib induced a synergistic growth inhibition in HCC827GR cells. The findings of our work reveal that ASN-MET-TOPK signaling axis as a novel mechanism contributed to gefitinib-resistance and combined utilization of gefitinib and MSeA holds potential to improve the efficacy for gefitinib-resistant NSCLC.
Background: T-LAK cell-originated protein kinase (TOPK), a serine/threonine kinase, is aberrantly overexpressed in human tumors and promotes malignant proliferation. Melanoma is a highly immunogenic tumor in which CD8+ T cell-mediated cytotoxicity is usually less effective in tumor control and responsive to immune checkpoint blockade. It is unclear whether the expression and functional characterization of TOPK within the immune cells affect the tumor microenvironment (TME) in patients with melanoma. This study aims to elucidate the expression pattern and immunoregulatory function of TOPK in CD8+ T lymphocytes during antitumor responses. Methods: Public single-cell RNA-sequencing (scRNA-seq) dataset analysis and flow cytometry assessed TOPK in tumor-infiltrating CD8+ T cells from patients with melanoma. Genetic deletion and pharmacological inhibition of TOPK using HI-TOPK-032 tested T cell-mediated melanoma control. Flow cytometry and tumor cell coculture killing assays measured effector release and target-cell apoptosis. Mechanistic analyses included assessment of interferon regulatory factor 5 (IRF5) expression, together with combination therapy using a programmed cell death protein 1 (PD-1)-blocking antibody in vivo. scRNA-seq of tumor-infiltrating lymphocytes (TILs) from Topkfl/fl and Cd8CreTopkfl/fl mice was also performed to define TOPK-dependent immune programs within the melanoma TME. Results: Single-cell transcriptomes identified a TOPK+ subset of tumor-infiltrating CD8+ T cells in melanoma, which was higher than that in normal lymph nodes (LNs), and exhibited suppressed cytotoxic and cytokine programs. CD8+ T cell-specific Topk deletion increased granzyme B (GzmB), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) secretion and improved tumor control. TOPK-deficient CD8+ T cells showed elevated activation-associated signaling pathways and immune effector gene expression. In murine TIL scRNA-seq, Cd8CreTopkfl/fl tumors exhibited increased effector and activation programs, reduced exhaustion and dysfunction programs, and enhanced immune crosstalk in the TME. Mechanistically, TOPK suppressed IRF5 expression and HI-TOPK-032 restored CD8+ T cell cytotoxicity in vitro and, with anti-PD-1, further inhibited tumor growth and increased intratumoral cytokine production. In human CD8+ T cells, enforced TOPK expression impaired cytotoxicity and cytokine secretion, reversed by IRF5 coexpression. Conclusions: These findings establish TOPK as the immune checkpoint limiting CD8+ T cell functionality in tumors and indicate the potential of TOPK inhibition as a strategy to augment T cell-based immunotherapies.
危险品化学品经营许可证（带存储）