Epithelial ovarian cancer (EOC) has a unique mode of metastasis, where cells shed from the primary tumour, form aggregates called spheroids to evade anoikis, spread through the peritoneal cavity, and adhere to secondary sites. We previously showed that the master kinase Liver kinase B1 (LKB1) is required for EOC spheroid viability and metastasis. We have identified novel (nua) kinase 1 (NUAK1) as a top candidate LKB1 substrate in EOC cells and spheroids using a multiplex inhibitor beads-mass spectrometry approach. We confirmed that LKB1 maintains NUAK1 phosphorylation and promotes its stabilization. We next investigated NUAK1 function in EOC cells. Ectopic NUAK1-overexpressing EOC cell lines had increased adhesion, whereas the reverse was seen in OVCAR8-NUAK1KO cells. In fact, cells with NUAK1 loss generate spheroids with reduced integrity, leading to increased cell death after long-term culture. Following transcriptome analysis, we identified reduced enrichment for cell interaction gene expression pathways in OVCAR8-NUAK1KO spheroids. In fact, the FN1 gene, encoding fibronectin, exhibited a 745-fold decreased expression in NUAK1KO spheroids. Fibronectin expression was induced during native spheroid formation, yet this was completely lost in NUAK1KO spheroids. Co-incubation with soluble fibronectin restored the compact spheroid phenotype to OVCAR8-NUAK1KO cells. In a xenograft model of intraperitoneal metastasis, NUAK1 loss extended survival and reduced fibronectin expression in tumours. Thus, we have identified a new mechanism controlling EOC metastasis, through which LKB1-NUAK1 activity promotes spheroid formation and secondary tumours via fibronectin production.
The association between malignancies and autoimmunity had been well-established. The proposed pathophysiology and causality can be bidirectional. For example, a paraneoplastic syndrome can be triggered by an underlying malignancy or vice versa, where chronic inflammation of organs affected by autoimmunity can induce malignant transformation such as the case with inflammatory bowel disease and colorectal cancer or primary sclerosing cholangitis and hepatobiliary cancer. This report presents a case of autoimmune phenomena, namely, autoimmune hemolytic anemia, pernicious anemia, and Graves disease associated with newly diagnosed breast cancer. We also highlight the postulated pathophysiologic mechanisms in an attempt to answer the question of whether the occurrence of these autoimmune phenomena in our patient is a result of the law of parsimony (Occam's razor), where clinical variables are pathogenically related, or the counterargument, where random events and diseases can take place simultaneously (Hickam's dictum).
The association between Moyamoya syndrome (MMS) and sickle cell disease (SCD) has been wellestablished in pediatric populations; however, limited literature exists documenting the characteristics and management of MMS in adult SCD patients. Studies have indicated the role of endovascular management in secondary stroke prevention for pediatric populations, with no current guidelines available for adult populations. Here, we describe a unique case of MMS in a 30-year-old patient with SCD and incidental protein S deficiency. Our unique case highlights a patient at high risk for neurosurgical intervention due to her hypercoagulable state who has benefitted from medical management. We also discuss current literature for the prevention of secondary cerebral vascular events and the role of further studies involving adult populations with MMS and SCD.
Epithelial ovarian cancer (EOC) cells form multicellular aggregates, or spheroids, and enter a dormant state during intraperitoneal metastasis. Dormant spheroids reduce anabolic metabolism and cell proliferation, which are linked to chemo-resistance. Liver kinase B1 (LKB1), encoded by the STK11 gene, is a critical regulator of stress metabolic signaling; LKB1 phosphorylates the downstream substrates AMP-activated protein kinase (AMPK) and AMPK-related kinases (ARKs) to mediate stress signaling. We have demonstrated that LKB1 expression and activity is required for EOC spheroid cell survival, yet knockdown of AMPKα1/α2 has no effect on viability. In addition, we have preliminary data demonstrating that phosphorylated AMPK is still maintained in EOC spheroids generated from CRISPR-mediated STK11-deleted cells, which completely lack LKB1 expression. Taken together, these results implicate the importance of other AMPK-independent effectors of LKB1 signaling in spheroid cell viability. Therefore, to identify critical downstream targets of LKB1-mediated signaling in EOC spheroids, we employed multiplex inhibitor beads/mass spectrometry (MIB/MS) using OVCAR8 STK11-knockout cells and OVCAR8 control cells grown in adherent and spheroid culture conditions. Using this proteomic approach, we identified NUAK1 as the sole ARK out of 12 different family members that is negatively affected by LKB1 loss. In fact, both phosphorylated and total NUAK1 protein expression are decreased in STK11-knockout cells and spheroids. NUAK1 can negatively control cell growth and proliferation by direct regulation of cell cycle checkpoint proteins in several cell systems; however, it has been relatively understudied in EOC. In analysis of the serous ovarian carcinoma data from TCGA, NUAK1 is infrequently altered (<2% of tumors) and it has the highest mean mRNA expression level as compared with the other 11 ARK genes. However, using immunoblot analysis, we show that NUAK1 protein is largely underexpressed in many established (n=15) and new ascites-derived EOC cell lines (n=22). In fact, further NUAK1 knockdown increased spheroid cell viability, size, and reattachment capability, whereas knockdown of its closely-related family member NUAK2 had no effect compared with the non-targeting siRNA control. Likewise, treatment with the pharmacologic NUAK1/2 inhibitor WZ4003 increased EOC cell growth and clonogenicity. Conversely, ectopic overexpression of NUAK1 reduced EOC cell growth and clonogenicity. Collectively, our data indicate that NUAK1 acts as a newly identified growth suppressor downstream of LKB1 metabolic stress signaling in EOC. We are currently investigating mechanisms regulating NUAK1 protein stability and activity in EOC cells, and whether activated LKB1-NUAK1 signaling promotes stress metabolic signaling during tumor dormancy in the context of EOC metastasis. Citation Format: Parima Saxena, Olga Collins, Yudith Ramos Valdes, Adrian Buensuceso, Kyle Francis, Kevin Brown, Karen Colwill, Anne-Claude Gingras, Robert Rottapel, Gabriel E. DiMattia, Trevor G. Shepherd. NUAK1 acts as a growth suppressor in epithelial ovarian cancer. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr A17.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.