Activation of AKT induces EZH2-mediated ß-catenin trimethylation in colorectal cancer.

Colorectal cancer (CRC) develops in part through the deregulation of different signaling pathways, including activation of the WNT/ß-catenin and PI3K/AKT pathways. Additionally, the lysine methyltransferase enhancer of zeste homologue 2 (EZH2) is commonly overexpressed in CRC. EZH2 canonically represses gene transcription by trimethylating lysine 27 of histone H3, but also has non-histone substrates. Here, we demonstrated that in CRC, active AKT phosphorylated EZH2 on serine 21. Phosphorylation of EZH2 by AKT induced EZH2 to interact with and methylate ß-catenin at lysine 49, which increased ß-catenin's binding to the chromatin. Additionally, EZH2-mediated ß-catenin trimethylation induced ß-catenin to interact with TCF1 and RNA polymerase II and resulted in dramatic gains in genomic regions with ß-catenin occupancy. EZH2 catalytic inhibition decreased stemness but increased migratory phenotypes of CRC cells with active AKT. Overall, we demonstrated that EZH2 modulates AKT-induced changes in gene expression through the AKT/EZH2/ß-catenin axis in CRC.

Activation of AKT induces EZH2-mediated ß-catenin trimethylation in colorectal cancer.

Colorectal cancer (CRC) develops in part through the deregulation of different signaling pathways, including activation of the WNT/ß-catenin and PI3K/AKT pathways. Enhancer of zeste homolog 2 (EZH2) is a lysine methyltransferase that is involved in regulating stem cell development and differentiation and is overexpressed in CRC. However, depending on the study EZH2 has been found to be both positively and negatively correlated with the survival of CRC patients suggesting that EZH2's role in CRC may be context specific. In this study, we explored how PI3K/AKT activation alters EZH2's role in CRC. We found that activation of AKT by PTEN knockdown or by hydrogen peroxide treatment induced EZH2 phosphorylation at serine 21. Phosphorylation of EZH2 resulted in EZH2-mediated methylation of ß-catenin and an associated increased interaction between ß-catenin, TCF1, and RNA polymerase II. AKT activation increased ß-catenin's enrichment across the genome and EZH2 inhibition reduced this enrichment by reducing the methylation of ß-catenin. Furthermore, PTEN knockdown increased the expression of epithelial-mesenchymal transition (EMT)-related genes, and somewhat unexpectedly EZH2 inhibition further increased the expression of these genes. Consistent with these findings, EZH2 inhibition enhanced the migratory phenotype of PTEN knockdown cells. Overall, we demonstrated that EZH2 modulates AKT-induced changes in gene expression through the AKT/EZH2/ ß-catenin axis in CRC with active PI3K/AKT signaling. Therefore, it is important to consider the use of EZH2 inhibitors in CRC with caution as these inhibitors will inhibit EZH2-mediated methylation of histone and non-histone targets such as ß-catenin, which can have tumor-promoting effects.

Platinum-induced mitochondrial OXPHOS contributes to cancer stem cell enrichment in ovarian cancer.

BACKGROUND: Platinum based agents-cisplatin and carboplatin in combination with taxanes are used for the treatment of ovarian cancer (OC) patients. However, the majority of OC patients develop recurrent, platinum resistant disease that is uniformly fatal. Platinum treatment enriches for chemoresistant aldehyde dehydrogenase (ALDH) + ovarian cancer stem cells (OCSCs), which contribute to tumor recurrence and disease relapse. Acquired platinum resistance also includes metabolic reprograming and switching to oxidative phosphorylation (OXPHOS). Chemosensitive cells rely on glycolysis while chemoresistant cells have the ability to switch between glycolysis and OXPHOS, depending on which pathway drives a selective advantage for growth and chemoresistance. High expression of genes involved in OXPHOS and high production of mitochondrial ROS are characteristics of OCSCs, suggesting that OCSCs favor OXPHOS over glycolysis. Based on connections between OCSCs, chemoresistance and OXPHOS, we hypothesize that platinum treatment induces changes in metabolism that contribute to platinum-induced enrichment of OCSCs. METHODS: The effect of cisplatin on mitochondrial activity was assessed by JC1 staining and expression of OXPHOS genes by RT-qPCR. Cisplatin-induced changes in Sirtuin 1 (SIRT1) levels and activity were assessed by western blot. Small molecule inhibitors of mitochondrial complex I and SIRT1 were used to determine if their enzymatic activity contributes to the platinum-induced enrichment of OCSCs. The percentage of ALDH + OCSCs in OC cells and tumor tissue from xenograft models across different treatment conditions was analyzed using ALDEFLUOR assay and flow cytometry. RESULTS: We demonstrate that platinum treatment increases mitochondrial activity. Combined treatment of platinum agents and OXPHOS inhibitors blocks the platinum-induced enrichment of ALDH + OCSCs in vitro and in vivo. Furthermore, platinum treatment increases SIRT1 levels and subsequent deacetylase activity, which likely contributes to the increase in platinum-induced mitochondrial activity. CONCLUSIONS: These findings on metabolic pathways altered by platinum-based chemotherapy have uncovered key targets that can be exploited therapeutically to block the platinum-induced enrichment of OCSCs, ultimately improving the survival of OC patients.

Pain points in parents' interactions with newborn screening systems: a qualitative study.

BACKGROUND & OBJECTIVES: This study aims to explore and elucidate parents' experience of newborn screening [NBS], with the overarching goal of identifying desiderata for the development of informatics-based educational and health management resources. METHODS: We conducted four focus groups and four one-on-one qualitative interviews with a total of 35 participants between March and September 2020. Participants were grouped into three types: parents who had received true positive newborn screening results; parents who had received false positive results; and soon-to-be parents who had no direct experience of the screening process. Interview data were subjected to analysis using an inductive, constant comparison approach. RESULTS: Results are divided into five sections: (1) experiences related to the process of receiving NBS results and prior knowledge of the NBS program; (2) approaches to the management of a child's medical data; (3) sources of additional informational and emotional support; (4) barriers faced by parents navigating the health system; and (5) recommendations and suggestions for new parents experiencing the NBS process. CONCLUSION: Our analysis revealed a wide range of experiences of, and attitudes towards the newborn screening program and the wider newborn screening system. While parents' view of the screening process was - on the whole - positive, some participants reported experiencing substantial frustration, particularly related to how results are initially communicated and difficulties in accessing reliable, timely information. This frustration with current information management and education resources indicates a role for informatics-based approaches in addressing parents' information needs.

ResultsMyWay: combining Fast Healthcare Interoperability Resources (FHIR), Clinical Quality Language (CQL), and informational resources to create a newborn screening application.

Newborn screening (NBS) can be life-changing for the families of infants who test positive for a rare condition. While resources exist to support these families, there can be delays in sharing these resources due to communication lag between the laboratory, result interpreting clinician, family of the newborn, and additional care providers. This delay can also be exacerbated when additional health history is required from the mother and infant. ResultsMyWay is a proof-of-concept application that uses Clinical Quality Language (CQL) to automate the search for this additional health history. It also translates the NBS results into Fast Healthcare Interoperability Resources (FHIR), increasing both the ease of exchange and the future utility of these data points. After the families are given the NBS results, ResultsMyWay then acts as a hub for several types of informational resources about the recently diagnosed condition.