Spatial Proteomic Analysis Highlights Molecular Reprogramming in Optic Nerve Invasive Retinoblastoma.

PURPOSE: Molecular reprogramming at the interface between malignant and non-malignant contributes to heterogeneity and metastasis across various cancers. The optic nerve metastasis serves as a significant prognostic indicator for mortality in retinoblastoma (RB). This study seeks to unveil the molecular underpinnings of this phenomenon.

METHODS

We conducted a spatial proteomic analysis to delineate the heterogeneity within three RB samples exhibiting optic nerve invasion (ONI): case 1 and case 2 comparing the optic nerve invasive (ONI) group and the intraretinal group, and case 3 comparing tumor boundary and center. Data were archived in Mendeley Data [V1] (doi: 10.17632/xvtw7gmhzx.1; doi: 10.17632/mbsh6pcsnc.1). Immunofluorescence was performed to validate the expression patterns in additional RB samples of ONI versus the intraretinal group (n = 3 for each), and tumor boundary and center of neural metastasis (n = 4 for each).

RESULTS

Spatial proteomic analysis identified significant alterations in cholesterol metabolism in optic nerve-invasive lesions compared with intraretinal lesions. The boundary of the invasive RB at the optic nerve demonstrated an upregulation of anaplerotic reaction and oxidative respiration, along with a significant enhancement of keratin-mediated cytoskeletal remodeling. Moreover, the boundary lesions exhibit epigenetic remodeling, following decreased lysine methyltransferase 5C (KMT5C) levels, an important regulator of the epithelial/mesenchymal transition. Consistently, immunofluorescence analysis of pyruvate carboxylase (PC), keratin 17 (KRT17), and KMT5C substantiated distinct expression patterns in tumor boundary and center lesions.

CONCLUSIONS

This study initially presents the spatial proteomic heterogeneity landscape in RB with ONI and uncovers its molecular reprogramming.