To be of clinical benefit for patients with ovarian cancer. DC

To be of clinical benefit for patients with ovarian cancer. DC are remarkable for their plasticity in directing T cell differentiation and effector function, and thus, the key to success may reside in our ability to educate DC to drive ovarian tumor antigen-specific Th17 responses. Several recent studies have indicated that regulation of the p38 and ERK MAPK signal transduction pathways in DC plays a central role in direction of T cell differentiation. Inhibition of MEK 1/2 and ERK MAPK signaling promotes IL-12 production and Th1 T cell responses, whereas inhibition of p38 MAPK increases signal transduction through ERK 1/2 and blocks IL-12 production [9]. At face value, these observations suggest that inhibition of p38 MAPK signaling would be disadvantageous for DC-driven anti-tumor T cell responses, since this would abrogate Th1 responses. However, p38 inhibition promotes differentiation and survival of monocyte-derived DC [10], and p38 inhibition or MEK/ERK MAPK activation restores deficiencies in DC function in myeloma patients [11], suggesting that treatment of DC with pharmacological inhibitors of pCancer Immunol Immunother. Author manuscript; available in PMC 2014 May 01.Cannon et al.Pagesignaling may confer benefit. Furthermore, p38 MAPK signaling in DC is associated with increased expression of IL-10 and the induction of tolerance in a mouse model of melanoma, thus contributing to the suppression of anti-tumor T cell responses, whereas inhibition of p38 signaling in DC from tumor-bearing mice markedly suppressed expression of IL-10 and restored the capacity of DC to stimulate T cells [12]. Of particular significance, blockade of the p38 pathway can attenuate regulatory T cell induction by DC and enhance the efficacy of DC vaccination [13], whereas blockade of the ERK pathway suppresses DC-driven Th17 responses [14], suggesting that p38 blockade (which enhances ERK phosphorylation) may favor a switch from Treg induction to Th17 differentiation and expansion. In this study, we show that treatment of ovarian tumor antigen-loaded, cytokine-matured DC with a combination of IL-15 and a p38 MAPK inhibitor (p38i) offers potent synergy in antagonism of Treg induction and redirection toward Th17 responses that correlate with strong CD8+ CTL activation. These observations open the door to the development of innovative DC vaccination strategies to boost Th17 immunity in ovarian cancer patients.Soticlestat NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptMaterials and methodsHuman subjects Ovarian cancer patients (n = 6) were recruited from patients attending the Women’s Oncology clinic in the Winthrop P.Coelenterazine Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, under an IRB-approved protocol.PMID:29844565 Blood samples were drawn at the time of surgery. Further blood draws (to a maximum of 5 draws of 70 mL each) were taken at any time up to 1 year following enrollment into the study. Healthy adult volunteers (n = 3) also donated blood for this study. Peripheral blood leukocytes (PBL) were recovered by gradient centrifugation over Lymphoprep (Greiner Bio-One), and cryopreserved in liquid nitrogen. Lymphoblastoid cell lines (LCL) Epstein arr virus-transformed LCL were established from by infection of PBL with the B95.8 strain of EBV, followed by culture in RPMI 1,640 medium supplemented with 3 mM glutamine, 5 10-5 M 2-mercaptoethanol (Sigma) and 10 fetal bovine serum (Valley Biomedical) (RPMI/10) and 1.0 /ml Cyclosporin A.