Effect of bone cells HO-1 ablaation in the communication between prostate cancer cells and bone progenitors

COTIGNOLA JAVIER; ZENCLUSSEN ANA C.; ANSELMINO NICOLAS; GERALDINE GUERON; STARBUCK MICHAEL; NAVONE NORA; ELBA VAZQUEZ

Sao Paulo

Congreso; Second AACR International Conference. Translational Cancer Medicine; 2018

AACR

Prostate cancer (PCa) is the second leading cause of cancer-associated death in men. Bone is the most common and frequently the unique site of PCa progression. Upon metastases, tumor cells interact with the bone microenvironment interrupting the osteoblastogenesis/osteoclastogenesis tissue balance. Inflammation is one of the main risk factors of this disease. In this context heme oxygenase 1 (HO-1) appears as a potential target in PCa maintaining the cellular homeostasis and counteracting the oxidative damage. We previously demonstrated that HO-1 has tumor suppressor properties in PCa. Our hypothesis is that HO-1 modulation in bone cells is implicated in the capacity of PCa cells to metastasize to bone, where in turn they disrupt bone homeostasis. Our aim was to assess the effect of PCa-produced factors under co-cultured with primary mouse osteoblasts (PMOs) isolated from BALB/c Hmox1 +/+, +/- and -/- mice. We used a Co-culture system of human PCa cells and PMOs isolated from Hmox-1 transgenic mice. cDNA samples of PC3 cells and transgenic mice PMOs were subjected to a transcriptional profiling by quantitative PCR analysis (RT-qPCR), using human and mouse specific primers. We assessed the expression levels of genes involved in tumorigenesis and bone remodeling, including IL6, IL8, PTHrP, ANXA2, DKK1, RunX2, Col1a1. ROS levels were determined in PMOs and PCa cells by flow cytometry using 2´,7´- Dichlorofluorescein diacetate. Histomorphometric analysis of transgenic animals? bones with less copies of hmox-1 exhibited decreased bone density with reduced bone remodeling parameters. Accordingly, a correlation between the expression of hmox-1 and runx2, col1a1, mcsf1, opg and il-6 was observed in PMOs. Flow cytometry studies showed two population of PMOs with different ROS levels. The high ROS levels population was increased in PMOs Het compared with WT, but was strong reduced in PMOs KO, showing restrained ROS tolerance in KO cells. PMOs gene expression was altered by Co-culture with PC3 cells showing a more osteoclastic profile. On the other hand, pre-treatment of tumor cells with Hemin (an specific inducer of HO-1) lead PMOs gene expression to a more pro-osteoblastic profile. These results highlight the relevance of bone HO-1 expression, not only in the regulation of bone cells function, but also in the modulation of the communication between PMOs and PCa secreted factors.