Background: Investigating the pathogenesis of non-small cell lung cancer (NSCLC) is crucial to identify early diagnostic markers and novel therapeutic targets. Myod family inhibitor (MDFI) has been associated with the occurrence and progression of tumors; however, its potential role in NSCLC remains uninvestigated. Therefore, this study explores the role of MDFI in NSCLC and its association with autophagy in disease progression.

Methods: In vitro cellular models and in vivo mouse models were used to assess the impact of MDFI in NSCLC progression. MDFI knockdown (sh-MDFI) and overexpression (oe-MDFI) cellular models were successfully established. Expression levels of MDFI were assessed using real-time quantitative polymerase chain reaction (RT-qPCR), while protein levels were analyzed using Western blot analysis. Cell proliferation, migration, and invasion abilities were determined using clonal formation, 5-ethynyl-2′-deoxyuridine (EdU), wound healing, and Transwell invasion assays, respectively. For rescue experiments, cells were subjected to 3-methyladenine (3-MA) treatment for 24 hours. The in vivo xenograft mouse model was established through subcutaneous injection of A549 cells. The expression levels of nuclear proliferation-associated antigen (Ki-67) were evaluated using immunohistochemistry (IHC).

Results: We observed significantly elevated MDFI expression in NSCLC cells (p < 0.05). MDFI overexpression promoted cell proliferation, migration, and invasion capabilities (p < 0.05); however, MDFI knockdown suppressed these cellular behaviors (p < 0.05). MDFI overexpression enhanced the microtubule-associated protein 1 light chain 3 II/I (LC3II/I) ratio and autophagy-related gene 12 (ATG12) expression, and decreased sequestosome-1 (p62) levels (p < 0.05), while MDFI knockdown showed an opposite trend (p < 0.05). Furthermore, 3-MA treatment counteracted MDFI overexpression-induced malignant behavior and autophagy of NSCLC cells (p < 0.05). The tumor experiment revealed that knocking down MDFI suppressed tumor growth and autophagy in nude mice (p < 0.05).

Conclusion: MDFI modulates NSCLC cell proliferation, migration, and invasion by regulating autophagy, underscoring MDFI as a potential biomarker and a novel therapeutic target.