Inhibition of CDK1 by RO-3306 Exhibits Anti-Tumorigenic Effects in Ovarian Cancer Cells and a Transgenic Mouse Model of Ovarian Cancer.

Ovarian cancer is the deadliest gynecological malignancy of the reproductive organs in the United States. Cyclin-dependent kinase 1 (CDK1) is an important cell cycle regulatory protein that specifically controls the G2/M phase transition of the cell cycle. RO-3306 is a selective, ATP-competitive, and cell-permeable CDK1 inhibitor that shows potent anti-tumor activity in multiple pre-clinical models. In this study, we investigated the effect of CDK1 expression on the prognosis of patients with ovarian cancer and the anti-tumorigenic effect of RO-3306 in both ovarian cancer cell lines and a genetically engineered mouse model of high-grade serous ovarian cancer (KpB model). In 147 patients with epithelial ovarian cancer, the overexpression of CDK1 was significantly associated with poor prognosis compared with a low expression group. RO-3306 significantly inhibited cellular proliferation, induced apoptosis, caused cellular stress, and reduced cell migration. The treatment of KpB mice with RO-3306 for four weeks showed a significant decrease in tumor weight under obese and lean conditions without obvious side effects. Overall, our results demonstrate that the inhibition of CDK1 activity by RO-3306 effectively reduces cell proliferation and tumor growth, providing biological evidence for future clinical trials of CDK1 inhibitors in ovarian cancer.

Anti-Tumor and Anti-Invasive Effects of ONC201 on Ovarian Cancer Cells and a Transgenic Mouse Model of Serous Ovarian Cancer.

ONC201 is a promising first-in-class small molecule that has been reported to have anti-neoplastic activity in various types of cancer through activation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as well as activation of mitochondrial caseinolytic protease P (ClpP). The present study was to explore the anti-tumor potential effect of ONC201 in ovarian cancer cell lines and in a transgenic mouse model of high grade serous ovarian cancer under obese (high fat diet) and lean (low fat diet) conditions. ONC201 significantly suppressed cell proliferation, induced arrest in G1 phase, and increased cellular stress and apoptosis, accompanied by dual inhibition of the AKT/mTOR/S6 and MAPK pathways in OC cells. ONC201 also resulted in inhibition of adhesion and invasion via epithelial-mesenchymal transition and reduction of VEGF expression. Pre-treatment with the anti-oxidant, N-acetylcysteine (NAC), reversed the ONC201-induced oxidative stress response, and prevented ONC201-reduced VEGF and cell invasion by regulating epithelial-mesenchymal transition protein expression. Knockdown of ClpP in ovarian cancer cells reduced ONC201 mediated the anti-tumor activity and cellular stress. Diet-induced obesity accelerated ovarian tumor growth in the KpB mouse model. ONC201 significantly suppressed tumor growth, and decreased serum VEGF production in obese and lean mice, leading to a decrease in tumoral expression of Ki-67, VEGF and phosphorylation of p42/44 and S6 and an increase in ClpP and DRD5, as assessed by immunohistochemistry. These results suggest that ONC201 may be a promising therapeutic agent to be explored in future clinical trials in high-grade serous ovarian cancer.

Targeting dopamine receptor D2 as a novel therapeutic strategy in endometrial cancer.

BACKGROUND: ONC201 is a dopamine receptor D2 (DRD2) antagonist that inhibits tumor growth in preclinical models through ClpP activation to induce integrated stress response pathway and mitochondrial events related to inhibition of cell growth, which is being explored in clinical trials for solid tumors and hematological malignancies. In this study, we investigated the anti-tumorigenic effect of ONC201 in endometrial cancer cell lines and a genetically engineered mouse model of endometrial cancer. METHODS: Cell proliferation was assessed by MTT and colony formation assays. Cell cycle and apoptosis were evaluated by Cellometer. Invasion capacity was tested using adhesion, transwell and wound healing assays. LKB1fl/flp53fl/fl mouse model of endometrial cancer were fed a control low fat diet versus a high fat diet to mimic diet-induced obesity. Following tumor onset, mice were treated with placebo or ONC201. Metabolomics and lipidomics were used to identify the obesity-dependent effects of ONC201 in the mouse endometrial tumors. DRD2 expression was analyzed by immunohistochemistry in human endometrioid and serous carcinoma specimens. DRD2 mRNA expression from the Cancer Genome Atlas (TCGA) database was compared between the four molecular subtypes of endometrial cancer. RESULTS: Increasing DRD2 expression in endometrial cancer was significantly associated with grade, serous histology and stage, as well as worse progression free survival and overall survival. Higher expression of DRD2 mRNA was found for the Copy Number High (CNH) subtype when compared to the other subtypes. ONC201 inhibited cell proliferation, induced cell cycle G1 arrest, caused cellular stress and apoptosis and reduced invasion in endometrial cancer cells. Diet-induced obesity promoted endometrial tumor growth while ONC201 exhibited anti-tumorigenic efficacy in the obese and lean LKB1fl/fl/p53fl/fl mice. Metabolomic analysis demonstrated that ONC201 reversed the obesity-driven upregulation of lipid biosynthesis and reduced protein biosynthesis in obese and lean mice. CONCLUSION: ONC201 has anti-tumorigenic effects in endometrial cancer cells and a transgenic mouse model of endometrial cancer, and DRD2 expression was documented in both human serous and endometrioid endometrial cancer. These studies support DRD2 antagonism via ONC201 as a promising therapeutic strategy for endometrial cancer that has already demonstrated pharmacodynamic activity and clinical benefit in both serous and endometrioid endometrial cancer patients.

Docosahexaenoic acid (DHA), an omega-3 fatty acid, inhibits tumor growth and metastatic potential of ovarian cancer.

Omega-3 polyunsaturated fatty acids (PUFAs), such as those found in fish oil, are thought to have anti-tumorigenic effects and may help to treat and prevent cancer, including ovarian cancer. Thus, we aimed to evaluate the potential of docosahexaenoic acid (DHA), an omega-3 PUFA, as a therapeutic agent in ovarian cancer cell lines and a transgenic mouse model of ovarian cancer. DHA significantly inhibited cellular proliferation, induced cell cycle arrest and caused apoptosis in Hey and IGROV-1 cells. Pre-treatment with the anti-oxidant, N-acetylcysteine (NAC), reversed DHA-induced caspase 3 activity and prevented DHA-reduced cell proliferation. DHA also induced cellular reactive oxygen species (ROS) and inhibited adhesion and invasion in IGROV-1 and Hey cells. Furthermore, treatment with DHA demonstrated anti-tumorigenic and anti-invasive activity in a K18-gT121 +/-; p53fl/fl; Brca1fl/fl mouse model of ovarian cancer including downregulation of Ki67 and VEGF expression. The data provide a preclinical rationale for applying DHA for dietary intervention and therapeutic adjunct in patients with ovarian cancer.

Current First-line Therapy for Ovarian Cancer: A Comprehensive Review.

IMPORTANCE: Ovarian, fallopian tube, and primary peritoneal cancers constitute the deadliest gynecologic malignancies. After primary cytoreductive surgery, there are several standard first-line cytotoxic treatments for providers to consider. Newer molecular targeted therapies are becoming more common and may have a role as first-line therapy in the future. OBJECTIVE: This article provides an evidence-based review of all approved standard therapies for first-line treatment of advanced-stage, high-grade serous ovarian cancer. Treatment schedules, dose modifications, and drug substitutions are reviewed. Ongoing trials and pending approvals for newer molecular therapies are discussed. EVIDENCE ACQUISITION: A comprehensive primary literature review was performed using MEDLINE, the Cochrane Collaborative Database, and PubMed. Guidelines from the National Comprehensive Cancer Network and the Society for Gynecologic Oncology were also reviewed. RESULTS: Seven different approved first-line regimens for high-grade serous ovarian cancer are available based on literature review. These vary in route of administration, dose intensity, drug combinations, and treatment schedules. Molecular targeted therapies, including antiangiogenic drugs and poly(ADP-ribose) polymerase inhibitors, have also been studied in multiple randomized controlled trials in the first-line setting. CONCLUSIONS AND RELEVANCE: Cytotoxic regimens remain the foundation of first-line treatment for high-grade serous ovarian cancer. Choosing which regimen is best for a patient depends on both patient and disease factors. Molecular therapies in first-line treatment are a promising and exciting possibility, with regulatory approval pending.

ONC201 demonstrates anti-tumorigenic and anti-metastatic activity in uterine serous carcinoma in vitro.

Uterine serous carcinoma (USC) represents an aggressive histologic subtype of endometrial cancer. It is associated with a poor prognosis, and improved therapies for women battling USCs are greatly needed. ONC201 is an orally bioavailable, first-in-class small molecule that induces tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) independent of p53. ONC201 has demonstrated anti-tumorigenic activity in pre-clinical models of solid tumors through induction of apoptosis and inactivation of the AKT/MAPK pathways. Recent phase I and II clinical trials have shown that ONC201 is well tolerated and may have single agent activity in high grade glioma patients among others. We sought to determine the effects of ONC201 on cell proliferation in USC and identify the mechanisms by which ONC201 inhibits cell growth in this disease. ONC201 inhibited cell proliferation in a dose-dependent manner in ARK1, ARK2 and SPEC-2 cell lines. The anti-proliferative activity of ONC201 in ARK1 and SPEC-2 cells was associated with induction apoptosis independent of p53 via both a TRAIL mediated apoptotic pathway and a mitochondrial apoptosis pathway. Treatment with ONC201 resulted in significant reduction in adhesion and invasion as well as inhibition of the AKT and MAPK pathways. In addition, ONC201 markedly potentiated the anti-tumorigenic effects of paclitaxel in USC cells. Our results suggest that ONC201 has significant anti-proliferative and anti-metastatic effects in USC cells through both induction of apoptosis and inhibition of the AKT and MAPK pathways. ONC201 and paclitaxel are a promising therapeutic combination in USC cells. Thus, ONC201 should be evaluated as a single agent and as a therapeutic partner with paclitaxel in future clinical trials of USC.

Nonoperative management of atypical endometrial hyperplasia and grade 1 endometrial cancer with the levonorgestrel intrauterine device in medically ill post-menopausal women.

OBJECTIVE: To assess the endometrial response rates to treatment with the levonorgestrel intrauterine device in post-menopausal women with atypical hyperplasia/endometrial intraepithelial neoplasia and grade 1 endometrioid (AH/EC) endometrial carcinoma who are not surgical candidates. METHODS: Chart review was undertaken of patients with AH/EC who underwent levonorgestrel intrauterine device insertion by a gynecologic oncologist within two academic health systems between 2002 and 2013. When available, tissue blocks were evaluated with immunohistochemical staining for progesterone receptor expression. RESULTS: A total of 41 patients received treatment for AH/EC with the levonorgestrel intrauterine device. Follow up sufficient to assess response occurred in 36 women (88%). Complete response was documented in 18 of 36 women (50%), no response in 8 patients (22%), partial response in 3 women (8%) and progression of disease in 7 patients (19%). Four of 18 patients with complete response (22%) later experienced relapse of hyperplasia or cancer. Four patients (10%) died during the study period: none had evidence of metastatic disease and 1 of the 4 woman died of perioperative complications following hysterectomy for stage I disease. Patients responding to treatment had significantly lower progesterone receptor expression on post-treatment biopsies. CONCLUSIONS: Intrauterine levonorgestrel is a viable treatment option for post-menopausal women with AH/EC who are poor candidates for standard surgical management. The response rate in this series is similar to published reports in premenopausal patients and includes cases of disease recurrence following conversion to benign endometrium.

Prior breast cancer and tamoxifen exposure does not influence outcomes in women with uterine papillary serous carcinoma.

OBJECTIVES: To evaluate progression-free survival (PFS) and overall survival (OS) outcomes in women diagnosed with uterine papillary serous carcinoma (UPSC) who have had (UPSCBR+) or have not had (UPSCBR-) an antecedent history of breast cancer and to correlate their outcomes to prior tamoxifen exposure. METHODS: Data were collected for women diagnosed with UPSC at two academic institutions between January 1997 and July 2012. Patient demographics, tumor histology, stage, and treatments were recorded. Patients were divided into two groups: those with and without a personal history of breast cancer. Within the UPSCBR+ cohort, we identified those with a history of tamoxifen use. Cox regression modeling was used to explore associations between selected covariates of interest and the time-to-event outcomes of PFS and OS. RESULTS: Of 323 patients with UPSC, 46 (14%) were UPSCBR+. Of these, 15 (33%) had a history of tamoxifen use. UPSCBR+ patients were older than UPSCBR- (median years, 72 vs. 68, p=0.004). UPSCBR+ women showed no significant difference in PFS or OS compared to UPSCBR- (p=0.64 and p=0.73 respectively), even after controlling for age (p=0.15 and p=0.48 respectively). Within the UPSCBR+ cohort, there was no difference in PFS or OS with or without tamoxifen exposure (p=0.98 and p=0.94 respectively). CONCLUSIONS: There was no difference in PFS or OS between the UPSCBR+ and UPSCBR- cohorts. We did not demonstrate significant OS or PFS differences in women who took tamoxifen prior to their endometrial cancer diagnosis. These findings have implications for counseling, and should be encouraging to women who are facing their second cancer diagnosis.