BACKGROUND Xanthomatous lesions of the pituitary have been linked to ruptured or hemorrhagic Rathke’s cleft cysts. Most cases are reported to resolve following radical resection. When recurrence does occur, there is no established treatment regimen. High-dose glucocorticoids have been reported to be beneficial in several published cases; however, their effects are often not sustained once therapy is discontinued. OBSERVATIONS The authors report the case of an adolescent male who developed recurrent xanthogranulomatous hypophysitis associated with a Rathke’s cleft cyst despite two surgical interventions. He was treated with a short course of dexamethasone followed by a maintenance course of celecoxib and mycophenolate mofetil. This regimen proved to be safe and well-tolerated, and it successfully prevented another recurrence of his xanthogranulomatous hypophysitis. LESSONS This case demonstrates a novel nonsurgical approach to the management of recurrent xanthogranulomatous hypophysitis. It suggests a potential application of a combined corticosteroid-sparing immunosuppressive and anti-inflammatory regimen in other cases of refractory xanthogranulomatous hypophysitis.

Background: Neuroblastoma is the most common extracranial solid tumor found in children, accounting for approximately 15% of cancer-related deaths. Many cellular processes have been discovered to play a role in neuroblastoma's potency, including a family of lipid kinases within the phosphoinositide 3-kinase (PI3K) signaling pathway that contribute to cell survival, proliferation, and differentiation. Targeting this pathway could unveil new treatment strategies that work to specifically treat each child's unique disease. BKM120 is a novel cancer therapeutic that targets the PI3K/Akt/mTOR signaling pathway and has recently been shown to have great potential in the clinic by acting on Class IA PI3Ks. Though Class IA PI3Ks hold multiple types, BKM120 has been shown to act preferentially on PIK3CA mutant isoforms. In this study we show the inhibitory effect of BKM120 on neuroblastoma cell lines that over-express PI3KCA, suggesting a promising role in the clinic for children with this expression profile. It has also been suggested that inhibitors of the PI3K pathway exert their inhibitory effects on cancer cells by destabilizing MYCN, a protein found over-expressed in approximately one third of neuroblastoma patients that encourages malignant progression of the disease. Methods: Neuroblastoma (NB) cell lines BE(2)-C and SMS-KCNR cells and patient lines MGT-002-13, MGT-003-08, MGT-014-11, and MGT-015-08 were used in these studies. Cell viability was measured using Calcein AM fluorescent assay at BKM120 doses 0.2uM, 0.5uM, and 1.0uM. Western blot analysis was used to measure PI3K pathway members including pAKT, p-mTOR, mTOR, and apoptosis markers including Cleaved Caspase 3, Caspase 3, PARP, and cPARP. ATP level per cell was measured using CyQuant fluorescent DNA assay combined with the Cell Titer GLO luminescent cell viability assay. IncuCyte imaging of sytox and kinetic caspase-3 reagent was used to measure apoptosis in NB cells treated with BKM120. Results: BKM120 is cytotoxic to NB cell lines with IC50's ranging from 0.9-5.5 uM. BKM120 increases protein expression levels of Cleaved Caspase 3 and cleaved PARP by inducing apoptosis and decreases MTOR, pAKT and MYCN at increasing drug doses. BKM120 decreases ATP/cell related to glycolytic metabolism activity in NB cell lines. Increased expression of MTOR and PI3KCD correlate with increased resistance to BKM120. Conclusion: This study indicates that BKM120 targets the MTOR/PI3K/AKT pathway and may play a role in MYCN driven tumors. In addition, BKM120 inhibits NB cell proliferation and induces caspase-mediated apoptosis in vitro in NB. Given the current lack of effective treatments and the high incidence of relapse and metastatic disease for patients, further assessment in clinical trial setting is needed to assess BKM120's therapeutic activity for children with NB. Citation Format: Monica M. Pomaville, Ping Zhao, Sarah DeCou, Abhinav B. Nagulapally, Jeffrey Bond, Giselle L. Saulnier Sholler. BKM120 is cytotoxic in neuroblastoma targeting the PI3K pathway. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3199.

Background: Neuroblastoma (NB) is the most common extracranial solid pediatric tumor and is associated with MYCN amplification. MYCN is a regulator of ornithine decarboxylase (ODC), the rate-limiting enzyme of polyamine biosynthesis. Inhibition of this pathway in MYCN-amplified NB tumors has been shown to be a target for treatment. Alpha-difluoromethylornithine (DFMO) inhibits ODC and is currently being used in a Phase II clinical trial for NB. BET inhibitors JQ1 and OTX-015 have been shown to be effective against MYCN-amplified cancers; it is hypothesized that they downregulate MYCN as well as cancer stem cell (CSC) signaling. We propose that inhibiting MYCN with a BET inhibitor, coupled with inhibition of ODC with DFMO, will result in enhanced inhibition of NB growth and tumor-initiating properties. Methods: Single and combination drug treatments were conducted on BE(2)-C, SMS-KCNR, CHLA90, and one patient-derived cell line. CellTiter-Glo Luminescent Cell Viability Assay was used to determine cell viability in 96-well plates. IC50 values were calculated with a four-parameter variable-slope dose response curve using GraphPad Prism v.5 software. Drug combination studies were conducted in MYCN amplified tumors BE(2)-C and SMS-KCNR using ray designs to evaluate for synergism. IncuCyte ZOOM Live-Cell Imaging system was used for kinetic monitoring of cytotoxicity and apoptosis in NB cells. Western blots measured protein levels of apoptosis markers (cleaved caspase 3 and cleaved PARP) and CSC markers (Nanog, Sox2, NF-kB, CXCR4, Lin28B, and MYCN). Neurosphere assays were used to evaluate tumor initiation via sphere formation. Results: Cell viability of MYCN amplified NB showed an IC50 range of 1.48-1.69 μM for JQ1 and 839.3 nM-2.36 μM for OTX-015; MYCN non-amplified NB showed an IC50 range of 4.22-11.58 μM for JQ1 and 2.99-11.03 uM for OTX-015. Combination treatment in MYCN NB had a synergistic effect, based on Loewe-additivity as the null hypothesis, for cell viability suppression by ray design experiments for BE(2)-C and SMS-KCNR. Western blots showed greater expression of apoptosis markers and decreased expression of CSC markers in combination relative to single drug treatments. A greater than 50% decrease in neurosphere formation with combination treatment in BE(2)-C, SMS-KCNR, and the patient cell line provides evidence for reduced CSC activity. IncuCyte imaging showed an increase in cell death with time post-treatment. Conclusion: The combination of DFMO with BET inhibitors has a synergistic effect in treating MYCN amplified NBs as shown by a decrease in cell viability. This combination targets CSC pathways and decreases tumor-initiating ability. Given the lack of effective treatment options for children with relapsed or refractory high-risk NB, this combination may be a promising novel therapy. Citation Format: Sarah DeCou, Ping Zhao, Tracey Avequin, Abhinav Nagulapally, Jeffrey Bond, Giselle Saulnier Sholler. DFMO synergizes with BET inhibitors targeting ODC and MYCN to impede neuroblastoma cell proliferation and tumor initiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 691. doi:10.1158/1538-7445.AM2017-691