Precision Targeting of AML through HERV‑K102 Inhibition: Treating Cancer via “Cell Explosion”
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Research Background: Revival of Dormant Ancient Viruses A substantial portion of the human genome consists of human endogenous retroviruses (HERVs), remnants of ancient viral infections. While generally quiescent, one HERV—HERV‑K102—is abnormally activated in patients with acute myeloid leukemia (AML) and has been shown to promote malignant cell proliferation.
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Innovative Approach: CRISPR‑Mediated Removal of the Cancer Cell Protective Shield (K‑Env) The investigators employed CRISPR‑Cas9 gene‑editing to precisely excise the envelope protein K‑Env of HERV‑K102.
- Proliferation Inhibition: AML cells lacking K‑Env displayed a marked slowdown in growth.
- Induction of Cell Death: Beyond simple cytotoxicity, a specialized form of programmed cell death was triggered.
- Core Mechanism: Induction of Inflammatory Cell Death (Pyroptosis) The principal finding of this study is that K‑Env deficiency provokes robust pyroptosis.
- Pathway: Intracellular activation of caspase‑1 cleaves gasdermin D, whose N‑terminal fragment forms pores in the plasma membrane, leading to cell swelling and eventual rupture.
- Evidence: Elevated extracellular lactate dehydrogenase (LDH) release and detection of cleaved gasdermin D confirmed the process at the molecular level.
- Therapeutic Efficacy Demonstrated in Mouse Models In vivo efficacy was validated.
- Tumor Growth Suppression: Selective K‑Env deletion in a murine xenograft model significantly impeded tumor expansion.
- Survival Benefit: Treated mice exhibited a substantial increase in overall survival compared with controls, underscoring the potential of HERV‑K102 as a novel AML therapeutic target.
- Outlook: Emergence of a Next‑Generation AML Immuno‑Oncology Strategy Pyroptosis releases inflammatory signals that recruit immune cells to the tumor microenvironment. Consequently, this strategy not only eliminates cancer cells but also re‑engages the host immune system, positioning it as a prospective next‑generation immuno‑oncology platform for AML.
OBJECTIVE: Several recent studies have focused on human endogenous retroviruses (HERVs). HERVs entered the human genome millions of years ago and are associated with various diseases including cancer and immune regulation. Among these, the HERV-K family exhibits the highest transcriptional activity. However, little is known about the expression of HERVs in acute myeloid leukemia (AML) and their potential as biomarkers or therapeutic targets. This study primarily investigated the role of HERV-K102 in AML development and explored the underlying mechanisms. METHODS: The expression profiles of HERV K102 in AML and normal samples were analyzed using The Cancer Genome Atlas (TCGA) database and AML cell lines. Knockout models were generated using CRISPR-Cas9-mediated deletion of the HERV-K102 envelope (K-Env). Cell viability and pyroptosis rates were measured using the MTT assay and flow cytometry, respectively. Transcriptome analysis was performed to identify differentially expressed genes and related pathways. Pyroptosis markers were detected using qRT-PCR and western blotting. The role of HERV-K102 in AML was validated using an inducible knockout xenograft tumor model. RESULTS: HERV-K102 was aberrantly activated and highly expressed in AML cells. K-Env depletion inhibited AML cell proliferation and promoted apoptosis. Furthermore, K-Env knockout induced pyroptosis, as indicated by increased lactate dehydrogenase (LDH) release and enhanced cleavage of caspase-1 and gasdermin D (GSDMD). Transcriptomic and functional analyses demonstrated that this process is mediated by S100A9 upregulation and activation of the NOD-like receptor protein 3 (NLRP3) inflammasome pathway. CONCLUSION: Our findings suggest that HERV-K102 Env may play an important role in AML pathogenesis and represents a novel diagnostic and therapeutic target.
AML is a difficult-to-treat hematologic malignancy, and existing targeted options are limited. By introducing HERV‑K102 as a new biomarker and therapeutic target, and by leveraging a pyroptosis‑inducing strategy that can eliminate cancer cells through immune mechanisms, this work holds promise for a substantial clinical impact.