Ceramides are bioactive lipids that mediate cell death in cancer cells, and ceramide-based therapy is now being tested in dose-escalating phase I clinical trials as a cancer treatment. Multiple nanoscale delivery systems for ceramide have been proposed to overcome the inherent toxicities, poor pharmacokinetics, and difficult biophysics associated with ceramide. Using the ceramide nanoliposomes (CNL), we now investigate the therapeutic efficacy and signaling mechanisms of this nanoscale delivery platform in refractory ovarian cancer. Treatment of ovarian cancer cells with CNL decreased the number of living cells through necroptosis but not apoptosis. Mechanistically, dying SKOV3 ovarian cancer cells exhibit activation of pseudokinase mixed lineage kinase domain-like (MLKL) as evidenced by oligomerization and relocalization to the blebbing membranes, showing necroptotic characteristics. Knockdown of MLKL, but not its upstream protein kinases such as receptor-interacting protein kinases, with siRNA significantly abolished CNL-induced cell death. Monomeric MLKL protein expression inversely correlated with the IC values of CNL in distinct ovarian cancer cell lines, suggesting MLKL as a possible determinant for CNL-induced cell death. Finally, systemic CNL administration suppressed metastatic growth in an ovarian cancer cell xenograft model. Taken together, these results suggest that MLKL is a novel pronecroptotic target for ceramide in ovarian cancer models. .

Background: The aim of this study was to investigate cytological features of Brenner tumors according to tumor grade using imprint cytology. Case: Between 2004 and 2015, intraoperative imprint cytology was performed on 8 patients with Brenner tumors suspected to be malignant neoplasmas on gross examination because of their large size and solid part. These consisted of 1 benign, 3 borderline, and 4 malignant tumors. In patients with benign and borderline tumors, naked nucleus-like stromal cells and tumor cells in a sheet-like arrangement were observed against a clear background. The nuclei were round to oval-shaped with finely granular chromatin patterns and small nucleoli. Papillary cell clusters and high nucleus-to-cytoplasm ratios were only observed in 1 borderline case. In cases with malignancy, the background was necrotic. The tumor cells occurred in large papillary clusters. The nuclei showed a high degree of nuclear atypia. Nuclear grooves were present in 6 of our 8 cases and they were scant in the malignant cases. Conclusion: Imprint cytology of Brenner tumors provided no characteristic findings to enable a definitive distinction of benign versus borderline tumors, but it enabled discrimination between malignant and other tumors. Imprint cytology can facilitate intraoperative diagnosis and aid in selecting the appropriate surgical procedure.

OBJECTIVES: Platinum-resistance is one of the most challenging difficulties in the treatment of ovarian cancer patients. To overcome this problem, we have explored a target molecule which can conquer platinum-resistance of ovarian cancer cells utilizing a functional genomics approach. MATERIALS AND METHODS: High-throughput functional siRNA screening was designed to target 6550 genes in cisplatin-resistant A2780 CP ovarian cancer cells. Cell viability was assessed by luminescent cell viability assay. After identifying a candidate molecule, cisplatin uptake was determined by atomic absorption spectrometry. DNA damages were determined by the western blotting and immunofluorescent staining using γH2AX antibodies. RESULTS: Through a functional screening, receptor tyrosine kinase TIE 1 was identified as a top candidate gene, of which inhibition give rise to enhancement of cisplatin sensitivity in ovarian cancer cells. Conversely, over-expression of TIE 1 gene significantly decreased susceptibility to cisplatin-induced cell death without affecting cisplatin uptake. DNA damages induced by cisplatin was significantly suppressed in TIE 1 over-expressed cells, raising novel potential mechanisms of TIE 1 in nucleotide excision repair system that removes chemicals adduct to DNA. In addition, over-expression of TIE 1 increased the expression of XPC, which is responsible for nucleotide excision repair. CONCLUSION: We have identified TIE 1 as a molecular target to overcome platinum-resistance in ovarian cancer cells. TIE 1 contribute platinum- resistance in ovarian cancer cells by promoting XPC-dependent DNA repairing system. Citation Format: Masumi Ishibashi, Masafumi Toyoshima, Mahy Egiz, Xuewei Zhang, Junko Minato, Shogo Shigeta, Kazuyuki Kitatani, Nobuo Yaegashi. INVOLVEMENT OF TIE–1 TYROSINE KINASE RECEPTOR IN CHEMO–RESISTANCE: POTENTIAL OF TIE1 AS A NOVEL THERAPEUTIC TARGET [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr NTOC-091.

We report a rare case of granulosa cell tumor in the broad ligament of the uterus which was diagnosed after laparoscopic surgery. The patient was a 29-year-old married woman, gravida 2, para 0. After visiting a previous hospital with a chief complaint of irregular menstruation, she was referred to our hospital for ovarian tumor diagnosis. Transvaginal ultrasonography showed a 5-cm tumor near the normal right ovary, and MRI also showed a mass containing cystic components and some solid elements located dorsal to the normal right ovary. Levels of the tumor markers CA19-9, CA125, and SCC were within their normal ranges. Based on these results, the patient underwent laparoscopic surgery for suspected right paraovarian tumor. A tumor growing in the right broad ligament was found, and laparoscopic resection of the right paraovarian tumor was performed. The histopathological examination showed an adult-type granulosa cell tumor. The patient has had no recurrence for 15 months since surgery.