The novel integrin-linked kinase inhibitor nilotinib suppresses cancer progression by promoting ubiquitylation of autoimmune regulator in oesophageal squamous cell carcinoma

Integrin-linked kinase (ILK) is a key oncogenic driver in oesophageal squamous cell carcinoma (ESCC). This study evaluated the antitumour effects of the novel ILK inhibitor Nilotinib and explored its downstream mechanisms. In vitro, TE-1 and KYSE150 cells were assessed using Cell Counting Kit-8, lactate dehydrogenase release, colony formation, 5-ehynyl-2 ' -deoxyuridine incorporation, flow cytometry, Transwell assays, and Western blotting to confirm ILK targeting and determine functional changes. Electron microscopy and fluorescent probes with flow cytometry were used to analyse mitochondrial alterations. In vivo, a nude mouse subcutaneous xenograft model was established to examine tumour growth after peritumoural Nilotinib administration; hematoxylin and eosin staining assessed tissue changes, and immunohistochemistry measured Ki67 and cleaved-caspase 3 expression. ILK overexpression alleviated Nilotinib-induced cytotoxicity, restored proliferation, increased proliferating cell nuclear antigen (PCNA) and Ki67, and reduced cleaved-caspase 3 and cleaved poly(ADP-ribose) polymerase (PARP), supporting ILK as a primary target. Nilotinib dose-dependently inhibited proliferation, invasion, and metastasis while promoting apoptosis, accompanied by downregulation of PCNA, Ki67, [matrix metalloproteinase 2 (MMP2), MMP9, and COX2] and upregulation of cleaved-caspase 3 and cleaved-PARP. In xenografts, Nilotinib significantly reduced tumour size and weight, decreased Ki67, and increased cleaved-caspase 3.RNA sequencing identified autoimmune regulator (AIRE) as a markedly downregulated molecule following Nilotinib treatment. Cycloheximide chase assays indicated accelerated AIRE protein degradation, while MG132 partially rescued AIRE levels, implicating proteasome-dependent degradation. Overall, Nilotinib suppresses ESCC progression by inhibiting ILK and destabilising AIRE, suggesting its potential as a targeted therapy for ILK-positive ESCC.