Loss of LKB1-NUAK1 signalling enhances NF-κB activity in a spheroid model of high-grade serous ovarian cancer

Abstract

High-grade serous ovarian cancer (HGSOC) is an aggressive malignancy often diagnosed at an advanced stage. Although most HGSOC patients respond initially to debulking surgery combined with cytotoxic chemotherapy, many ultimately relapse with platinum-resistant disease. Thus, improving outcomes requires new ways of limiting metastasis and eradicating residual disease. We identified previously that Liver kinase B1 (LKB1) and its substrate NUAK1 are implicated in EOC spheroid cell viability and are required for efficient metastasis in orthotopic mouse models. Here, we sought to identify additional signalling pathways altered in EOC cells due to LKB1 or NUAK1 loss-of-function. Transcriptome analysis revealed that inflammatory signalling mediated by NF-κB transcription factors is hyperactive due to LKB1-NUAK1 loss in HGSOC cells and spheroids. Upregulated NF-κB signalling due to NUAK1 loss suppresses reactive oxygen species (ROS) production and sustains cell survival in spheroids. NF-κB signalling is also activated in HGSOC precursor fallopian tube secretory epithelial cell spheroids, and is further enhanced by NUAK1 loss. Finally, immunohistochemical analysis of OVCAR8 xenograft tumors lacking NUAK1 displayed increased RelB expression and nuclear staining. Our results support the idea that NUAK1 and NF-κB signalling pathways together regulate ROS and inflammatory signalling, supporting cell survival during each step of HGSOC pathogenesis. We propose that their combined inhibition may be efficacious as a novel therapeutic strategy for advanced HGSOC.

Salt-inducible kinase 3 protects tumor cells from cytotoxic T-cell attack by promoting TNF-induced NF-κB activation

“…Additionally, LKB1 is a known negative regulator of the NF-κB signaling pathway. 76 77 Hence, we could not confirm a role of LKB1 in activating SIK3 and, in turn, NF-κB on TNF stimulation. Among other reported upstream regulators of SIK3, AKT is activated on TNF stimulation.…”

Copy number alterations in stage I epithelial ovarian cancer highlight three genomic patterns associated with prognosis

“…STK11 is the causative gene of the Peutz-Jeghers syndrome, one of the germline syndromes associated with increased susceptibility to different tumors, among which breast and ovarian tumors [20]. The loss of the LKB1 activity has been reported to be an early tumorigenic event favoring the development of HGSOC from ovarian surface epithelial cells in murine models along with the deletion of PTEN [21] and to participate in the upregulation of the NF-kB pathway in HGSOC cells models [22]. On the contrary, ZNF516 is a less known Zinc Finger protein involved in transcription regulation, but its cellular functions are not completely described; yet, it has been involved in replication stresses and particularly its loss was associated with increases chromosome instability along with other potential tumor suppressor genes located on the same chromosome arm, 18q [12], and further studies will be necessary to clarify the role of this gene in genomic instability.…”

Gain-of-function p53R175H blocks apoptosis in a precursor model of ovarian high-grade serous carcinoma

“…For Trp53 deletion, two independent pSpCas9-sgTrp53 plasmids were generated as previously described 52 , using the Trp53 -targeting sequences 5′-AGTGA AGCCC TCCGA GTGTCagg-3′ (site 1) and 5′-AACAG ATCGT CCATG CAGTGagg-3′ (site 2). OVE cells at 80% confluency were transfected with 1.5 µg of each pSpCas9-sgTrp53 plasmid using Lipofectamine LTX and PLUS reagents (Invitrogen) according to the manufacturer’s instructions.…”