Spheroid growth in ovarian cancer alters transcriptome responses for stress pathways and epigenetic responses.

Ovarian cancer is the most lethal gynecological cancer, with over 200,000 women diagnosed each year and over half of those cases leading to death. These poor statistics are related to a lack of early symptoms and inadequate screening techniques. This results in the cancer going undetected until later stages when the tumor has metastasized through a process that requires the epithelial to mesenchymal transition (EMT). In lieu of traditional monolayer cell culture, EMT and cancer progression in general is best characterized through the use of 3D spheroid models. In this study, we examine gene expression changes through microarray analysis in spheroid versus monolayer ovarian cancer cells treated with TGFß to induce EMT. Transcripts that included Coiled-Coil Domain Containing 80 (CCDC80), Solute Carrier Family 6 (Neutral Amino Acid Transporter), Member 15 (SLC6A15), Semaphorin 3E (SEMA3E) and PIF1 5'-To-3' DNA Helicase (PIF1) were downregulated more than 10-fold in the 3D cells while Inhibitor Of DNA Binding 2, HLH Protein (ID2), Regulator Of Cell Cycle (RGCC), Protease, Serine 35 (PRSS35), and Aldo-Keto Reductase Family 1, Member C1 (AKR1C1) were increased more than 50-fold. Interestingly, EMT factors, stress responses and epigenetic processes were significantly affected by 3D growth. The heat shock response and the oxidative stress response were also identified as transcriptome responses that showed significant changes upon 3D growth. Subnetwork enrichment analysis revealed that DNA integrity (e.g. DNA damage, genetic instability, nucleotide excision repair, and the DNA damage checkpoint pathway) were altered in the 3D spheroid model. In addition, two epigenetic processes, DNA methylation and histone acetylation, were increased with 3D growth. These findings support the hypothesis that three dimensional ovarian cell culturing is physiologically different from its monolayer counterpart.

The Heat Shock Transcription Factor HSF1 Induces Ovarian Cancer Epithelial-Mesenchymal Transition in a 3D Spheroid Growth Model.

Ovarian cancer is the most lethal gynecological cancer, with over 200,000 women diagnosed each year and over half of those cases leading to death. The proteotoxic stress-responsive transcription factor HSF1 is frequently overexpressed in a variety of cancers and is vital to cellular proliferation and invasion in some cancers. Upon analysis of various patient data sets, we find that HSF1 is frequently overexpressed in ovarian tumor samples. In order to determine the role of HSF1 in ovarian cancer, inducible HSF1 knockdown cell lines were created. Knockdown of HSF1 in SKOV3 and HEY ovarian cancer cell lines attenuates the epithelial-to-mesenchymal transition (EMT) in cells treated with TGFß, as determined by western blot and quantitative RT-PCR analysis of multiple EMT markers. To further explore the role of HSF1 in ovarian cancer EMT, we cultured multicellular spheroids in a non-adherent environment to simulate early avascular tumors. In the spheroid model, cells more readily undergo EMT; however, EMT inhibition by HSF1 becomes more pronounced in the spheroid model. These findings suggest that HSF1 is important in the ovarian cancer TGFß response and in EMT.

Interlaboratory comparison of in vitro bioassays for screening of endocrine active chemicals in recycled water.

In vitro bioassays have shown promise as water quality monitoring tools. In this study, four commercially available in vitro bioassays (GeneBLAzer(®) androgen receptor (AR), estrogen receptor-alpha (ER), glucocorticoid receptor (GR) and progesterone receptor (PR) assays) were adapted to screen for endocrine active chemicals in samples from two recycled water plants. The standardized protocols were used in an interlaboratory comparison exercise to evaluate the reproducibility of in vitro bioassay results. Key performance criteria were successfully achieved, including low background response, standardized calibration parameters and high intra-laboratory precision. Only two datasets were excluded due to poor calibration performance. Good interlaboratory reproducibility was observed for GR bioassay, with 16-26% variability among the laboratories. ER and PR bioactivity was measured near the bioassay limit of detection and showed more variability (21-54%), although interlaboratory agreement remained comparable to that of conventional analytical methods. AR bioassay showed no activity for any of the samples analyzed. Our results indicate that ER, GR and PR, were capable of screening for different water quality, i.e., the highest bioactivity was observed in the plant influent, which also contained the highest concentrations of endocrine active chemicals measured by LC-MS/MS. After advanced treatment (e.g., reverse osmosis), bioactivity and target chemical concentrations were both below limits of detection. Comparison of bioassay and chemical equivalent concentrations revealed that targeted chemicals accounted for ≤5% of bioassay activity, suggesting that detection limits by LC-MS/MS for some chemicals were insufficient and/or other bioactive compounds were present in these samples. Our study demonstrated that in vitro bioassays responses were reproducible, and can provide information to complement conventional analytical methods for a more comprehensive water quality assessment.