OncoTherad immunotherapy plus platelet rich plasma as potential therapeutic strategy for ovarian cancer: The role of toll-like receptors 2 and 4 signaling pathways.

Abstract

e17602 Background: Ovarian cancer (OC) has the most devastating death rate of gynecological cancers with only 44% of women surviving 5 years after diagnosis. Toll-like receptors (TLRs) signaling can play an important role in the OC treatment. TLR activation in immune cells can help activate an effective antitumor response. In this scenario, a new perspective is represented by combined OncoTherad (MRB-CFI-1) immunotherapy and Platelet Rich Plasma (PRP). OncoTherad (MRB-CFI-1) leads to the distinct stimulation of the innate immune system mediated by TLR2 and TLR4, resulting in an increased activation of the IFN signaling pathway. Also, PRP acts on immune activation and exerts antitumor effects. This study characterized the histopathological and molecular effects of the OncoTherad associated with PRP in the treatment of OC chemically induced in rats and described the possible mechanisms of action of this association involving the TLRs 2 and 4 signaling pathways. Methods: Fischer 344 female rats were divided into 5 groups (n = 7 animals per group): Control (Sham surgery) group; Cancer (7,12 dimethylbenzoanthracene – DMBA injection in the ovarian bursa, 1.25 mg/kg) group; OncoTherad (20mg/kg) group; PRP (328.103 – 549.103 platelets/mm3) group and; OncoTherad+PRP (same doses of the isolated treatments) group. Intraperitoneal doses were administered twice a week for 4 weeks. Immunohistochemistry was analyzed as total immunoreactivity and intensity of immunoreaction. Results: Our results showed serous type ovarian carcinoma, follicular atresia, absence of corpora lutea and hyperplasia of the germinal epithelium and tunica albuginea in the Cancer group. The histopathological changes in the PRP group were similar as Cancer group. In contrast, the animals treated with OncoTherad singly or in combination with PRP showed decrease of ovarian neoplastic lesions and histopathological recovery. TLR4 and IL-6 immunoreactivities were significantly lower (p < 0.05) in the Cancer group. PRP treatment reduced (p < 0.05) TLR2. In the Oncotherad+PRP group, the immunoreactivities of TLR4, MyD88, IRF-3 and TNF-α were lower. OncoTherad treatment alone led to stimulation of the innate immune system mediated by TLR2 and TLR4, resulting in an increased activation of the MyD88 signaling pathway (intensified IL-6 and TNF-α immunoreactivities). Conclusions: OncoTherad immunotherapy was able to reduce ovarian lesions and stimulated the TLR2 and 4 signaling pathways in the OC microenvironment, leading to antitumor effects by activating the production of inflammatory cytokines. Thus, OncoTherad immunotherapy could be considered an important therapeutic strategy for OC.