Front Genet. 2026 ;17
1926600
Background: Malignant pleural mesothelioma (PM) is a highly aggressive thoracic malignancy with an extremely poor prognosis and limited effective therapeutic strategies, representing a critical unmet clinical need. Fanconi anemia complementation group D2 (FANCD2) is a critical effector of the cellular DNA damage response system and plays a central role in maintaining genomic integrity. While the genoprotective functions of FANCD2 have been extensively characterized, its specific biological roles and molecular regulatory mechanisms in the malignant progression of PM remain poorly understood. The current study aimed to evaluate FANCD2 expression and its clinical associations in PM and to examine the effects of transient FANCD2 knockdown in NCI-H2052 cells.
Methods: Comprehensive bioinformatics analyses were performed based on public transcriptomic data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases to profile FANCD2 expression patterns and evaluate its clinical prognostic value in PM. Differential expression analysis was applied to confirm the aberrant upregulation of FANCD2 in PM tissues, and the associations of FANCD2 expression levels with tumor pathological staging and patient clinical prognosis were systematically assessed. Western blotting was further performed to evaluate the protein expression status of FANCD2 in clinical PM specimens and NCI-H2052 cells, with normal tissues and corresponding normal cells included as control groups. Transient FANCD2 knockdown was achieved in NCI-H2052 cells using two independent small interfering RNAs (siRNAs). A series of functional experiments were conducted to determine the effects of FANCD2 silencing on the proliferation, wound closure, and apoptosis of NCI-H2052 cells. For mechanistic exploration, the expression levels of core apoptotic proteins were detected to evaluate the association between FANCD2 depletion and Caspase/PARP-related apoptotic signaling. In addition, tumor immune infiltration analysis was performed to investigate the correlation between FANCD2 expression and M2 macrophage infiltration within the PM tumor microenvironment (TME). FANCD2 rescue and Z-VAD-FMK inhibition experiments were performed to further evaluate the involvement of caspase-dependent apoptosis.
Results: Bioinformatics results demonstrated that FANCD2 was significantly upregulated in PM tissues relative to normal control samples. Higher FANCD2 expression was associated with tumor T stage and unfavorable survival outcomes in the exploratory TCGA-MESO analysis. Consistently, Western blotting confirmed markedly increased FANCD2 protein levels in both clinical PM tissues and NCI-H2052 cells. Functional assays in NCI-H2052 cells revealed that siRNA-mediated FANCD2 knockdown significantly suppressed cell proliferation and reduced wound-closure capacity of NCI-H2052 cells, whereas it significantly increased apoptosis. Mechanistic investigations further found that FANCD2 silencing was associated with increased levels of caspase/PARP-related apoptotic markers, as evidenced by the markedly enhanced protein levels of cleaved caspase-3, cleaved caspase-8, cleaved caspase-9, and cleaved PARP. FANCD2 restoration and pharmacological caspase inhibition partially reversed FANCD2 knockdown-induced growth suppression and apoptosis, further supporting the involvement of caspase-dependent apoptotic signaling. Moreover, TME immune correlation analysis indicated that high FANCD2 expression was positively associated with M2 macrophage infiltration in PM tumors. These findings represent exploratory correlations derived from computational immune-cell estimation.
Conclusion: In summary, FANCD2 may contribute to PM progression by supporting malignant phenotypes and limiting apoptosis. FANCD2 restoration and caspase inhibition partially reversed the growth suppression and apoptosis induced by FANCD2 knockdown, supporting the involvement of caspase-dependent apoptotic signaling. In addition, FANCD2 expression was positively associated with the computationally estimated proportion of M2 macrophages, suggesting that FANCD2 may represent an exploratory prognostic marker and a candidate therapeutic target for further investigation in PM.
Keywords: apoptosis; bioinformatics; fanconi anemia complementation group D2; pleural mesothelioma; prognosis