Organelle resolved proteomics uncovers PLA2R1 as a novel cell surface marker required for chordoma growth.

Chordomas are clinically aggressive tumors with a high rate of disease progression despite maximal therapy. Given the limited therapeutic options available, there remains an urgent need for the development of novel therapies to improve clinical outcomes. Cell surface proteins are attractive therapeutic targets yet are challenging to profile with common methods. Four chordoma cell lines were analyzed by quantitative proteomics using a differential ultracentrifugation organellar fractionation approach. A subtractive proteomics strategy was applied to select proteins that are plasma membrane enriched. Systematic data integration prioritized PLA2R1 (secretory phospholipase A2 receptor-PLA2R1) as a chordoma-enriched surface protein. The expression profile of PLA2R1 was validated across chordoma cell lines, patient surgical tissue samples, and normal tissue lysates via immunoblotting. PLA2R1 expression was further validated by immunohistochemical analysis in a richly annotated cohort of 25-patient tissues. Immunohistochemistry analysis revealed that elevated expression of PLA2R1 is correlated with poor prognosis. Using siRNA- and CRISPR/Cas9-mediated knockdown of PLA2R1, we demonstrated significant inhibition of 2D, 3D and in vivo chordoma growth. PLA2R1 depletion resulted in cell cycle defects and metabolic rewiring via the MAPK signaling pathway, suggesting that PLA2R1 plays an essential role in chordoma biology. We have characterized the proteome of four chordoma cell lines and uncovered PLA2R1 as a novel cell-surface protein required for chordoma cell survival and association with patient outcome.

Visualización de orgánulos celulares en microscopía de fluorescencia / Display cell organelles in fluorescence microscopy

Conferencia Presentada en el marco del del 2do Congreso Nacional de la Asociación de Anatomistas de Córdoba (ADACO), y el 1er Encuentro latinoamericano de Anatomistas y el 1erEncuentro Latinoamericano de Histólogos y Embriólogos. El resultado de tratar células fijadas o vivas con fluorocromos suele ser muy distinto, dependiendo fundamen-talmente de la membrana plasmática. Fluorocromos que tiñen algunos componentes en células fijadas, marcanotras estructuras en células vivas. El marcaje celular vital es ahora muy apreciado para visualizar orgánulos, evaluar la viabilidad celular y estudiar la incorporación de compuestos con actividad biológica.

The result of treating fixed or live cells with fluorescent dyes is often very different, depending fundamentaltally of the plasma membrane. Some components fluorochromes stained fixed cells labeled other structures in living cells. The vital cell labeling is now appreciated to visualize organelles assess cell viability and to study the incorporation of compounds with biological activity.