Abstract A81: Heme oxygenase 1 alters the adhesive properties of prostate tumor cells growing in coculture with bone cells
Authors: Paez Alejandra Veronica , Anselmino Nicolas , Valacco Pia , Vazquez Elba Susana , Gueron Geraldine 
Published: May 2019

Prostate cancer (PCa) is the second leading type of cancer in men. PCa cells display abnormalities in their adhesive properties which result in an augmented capacity to resist chemotherapy and colonize other organs such as bone. We have recently shown that heme-oxygenase 1 (HO¬-1) has a strong anti¬tumoral effect in PCa through its interaction with cytoskeletal proteins, which regulate filopodia formation towards a more adhesive phenotype.

Given the osteomimetic properties of PCa cells, we used a coculture system where tumoral cells and bone cells share the medium but are not in direct physical contact. PC3 cells pretreated or not with hemin (HO-1 pharmacologic inducer, 50μΜ, 24h) were cocultured with the murine preosteoblastic (MC3T3) or preosteoclastic (RAW) cell line. The conditioned media (CM) from the cocultures were collected and added to new PC3 cultures in order to study changes in tumor cells' adhesiveness. After 24 h with the different CM, cells were fixed and stained with rhodamine-phalloidin to analyze contact among cells and filopodia in each cell individually.

Results show that the CM from the coculture between PC3 cells and MC3T3 or RAW cells have a negative impact both in the number of filopodia per cell and contacts among them. However, when PC3 cells were pretreated with hemin prior to coculture, the number of filopodia and cell contacts are reestablished. Interestingly, PC3 cells cultured with CM from the coculture system displayed more covered area after 6 h of exposure in a wound healing assay, compared to CM from cocultures with PC3 cells pretreated with hemin.

Finally, to identify the released factors in the coculture responsible for changing the adhesive properties of PC3 cells, we performed a mass spectrometry analysis followed by gene ontology analysis using DAVID software. Our analysis revealed more than 30 proteins released differentially in the coculture CM involved in the adhesiveness of the cell, such as cadherins (PCDHGA10, FAT4, CDH1, CDH10), collagen (COL2A1), and several proteins associated to cell detachment (GATAD2A, KANK2, BCAS3, CAMSAP1, EPPK1, FLNC, TMPPE).

Altogether, our findings demonstrate that HO-1 modulation in PCa cells induces morphologic changes towards a less invasive phenotype through different proteins released as a consequence of the communication between PCa and bone cells. These data also show the relevance of the cytoskeleton regulating proteins as potential therapeutic targets against the aggressive and metastatic disease.

Citation Format: Alejandra Veronica Paez, Nicolas Anselmino, Pia Valacco, Elba Susana Vazquez, Geraldine Gueron. Heme oxygenase 1 alters the adhesive properties of prostate tumor cells growing in coculture with bone cells [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr A81.