Mapping a high-risk progression-associated epithelial state in laryngeal dysplasia at single-cell resolution identifies PLK1 as a potential therapeutic target

Laryngeal squamous cell carcinoma (LSCC) arises from precancerous lesions, yet the cellular and molecular determinants of malignant progression remain incompletely defined. To characterize transcriptional states associated with this transition, we performed single‑cell RNA sequencing on tissues collected from patients with laryngeal dysplasia, carcinoma in situ, and invasive LSCC. Our analysis identified a set of fate-determining genes (e.g., NOC2L) governing epithelial differentiation and pinpointed a high-risk progression-associated epithelial state (Epi-C3). This subpopulation, characterized by TOP2A⁺HMGB2⁺PTTG1⁺ expression, is driven by a network of cell-cycle hub genes, with PLK1 emerging as a central node and a marker of poor prognosis. Cell–cell communication analysis further predicts that Epi-C3 may engage in MIF-mediated signaling with macrophages, suggesting a potential role in modulating the tumor microenvironment. Given PLK1’s central role within this regulatory network, we bioinformatically screened the traditional formula ReYanNingHeJi and identified the flavonoid quercetin as a potential candidate compound affecting PLK1-associated signaling. Quercetin suppressed the proliferation of LSCC cell lines and xenografts by inducing cell-cycle progression impairment and decreasing phosphorylation along the PLK1/CDC25C/Cyclin B1 axis; importantly, its anti‑proliferative effect was abolished by PLK1 knockdown, supporting the involvement of PLK1-associated signaling in mediating the anti-proliferative effects of quercetin. This study characterizes progression-associated epithelial programs in LSCC at single-cell resolution, identifies Epi-C3 as a high-risk progression-associated epithelial state regulated by a PLK1-associated transcriptional network, supports the potential of quercetin as a therapeutic candidate targeting PLK1-associated progression programs.