462 Background: The activity of the receptor activator of nuclear factor-kβ RANK/RANKL in cancer cells has been correlated with tumor progression and poor prognosis in solid tumors including bladder cancer. Regulatory T cells (Tregs), often identified by FOXP3 biomarker, suppress the anti-tumor response and allow immune tolerance through suppression of T cells. Immunomodulator OncoTherad is an inorganic phosphate nanocomplex associated with glycosidic protein, developed by the University of Campinas/Brazil, with antitumor effects. Previous reports have demonstrated immune activation and antitumor effects of Platelet Rich Plasma (PRP). We evaluated the effects of OncoTherad associated with PRP in the RANK/RANKL system and Tregs in a mouse model of non-muscle invasive bladder cancer (NMIBC). Methods: C57BL/6J mice were assigned to groups (n = 42): Control; Cancer (N-ethyl-N-nitrosourea carcinogen, 50 mg/ml); PRP (0.1 ml); OncoTherad (20 mg/ml); OncoTherad+PRP 10 mg/ml and OncoTherad+PRP 20 mg/ml. The intravesical doses (0.1 ml) were instilled once a week for 6 consecutive weeks after induction. Results: After NMIBC induction, all animals in the Cancer group showed flat carcinoma in situ (pTis) and both percentages of RANK, RANKL, OPG, and FOXP3 positive cells and the intensity of immunoreaction for these antigens were significantly higher in comparison with healthy animals. In addition to ensuring this NMIBC model, these results indicated the involvement of RANK/RANKL in urothelial carcinogenesis and the presence of Tregs in a suppressed immune tumor microenvironment. Mice treated with PRP only showed a 28.6% rate of tumor progression inhibition (TPI) and exhibited papillary urothelial carcinoma (pTa) and pTis. In this group, the intensity of the RANKL and FOXP3 immunoreaction was weaker when compared to the Cancer group. Thus, PRP showed immunomodulatory effects, reducing Tregs that are sources of RANKL. Oncotherad immunotherapy led to an TPI of 85.7%, and benign flat hyperplasia was the most frequent diagnosis. Oncotherad reduced the total RANK and RANKL immunoreactivities and decreased the intensity of RANKL immunostaining in comparison to the Cancer. In the OncoTherad+PRP 10 mg/ml or 20 mg/ml group, TPI was 71.4%, with a predominance of non-malignant lesions such as flat hyperplasia, low-grade intraurothelial neoplasia, and reactive atypia. Treatments with Oncotherad and Oncotherad plus PRP decreased the percentage of FOXP3+ cells and reduced the intensity of FOXP3 immunoreaction compared to the Cancer and PRP groups. Conclusions: The tumor inhibition obtained with Oncotherad plus PRP was related to the alteration of the immune profile of the tumor microenvironment by decreasing RANK/RANKL expression and Tregs, resulting in an effective immune response against the tumor.
IL-13Rα1 Suppresses Tumor Progression in Two-stage Skin Carcinogenesis Model by Regulating Regulatory T Cells
