NEAT1-SOD2 Axis Confers Sorafenib and Lenvatinib Resistance by Activating AKT in Liver Cancer Cell Lines

This study investigated the effects of a long noncoding RNA, nuclear paraspeckle assembly transcript 1 (NEAT1) variant 1 (NEAT1v1) on drug resistance in liver cancer cell lines. NEAT1 knockdown activated mitogen-activated protein kinase (MAPK) signaling pathways, including MAPK kinase (MEK)/extracellular signal-regulated kinase (ERK), but suppressed AKT. Moreover, NEAT1 knockdown sensitized liver cancer cells to sorafenib and lenvatinib, both clinically used for treating hepatocellular carcinoma, whereas it conferred resistance to an AKT-targeted drug, capivasertib. NEAT1v1 overexpression suppressed MEK/ERK and activated AKT, resulting in resistance to sorafenib and lenvatinib and sensitization to capivasertib. Superoxide dismutase 2 (SOD2) knockdown reverted the effects of NEAT1v1 overexpression on the sensitivity to the molecular-targeted drugs. Although NEAT1 or SOD2 knockdown enhanced endoplasmic reticulum (ER) stress, concomitant with the suppression of AKT, taurodeoxycholate, an ER stress suppressor, did not restore AKT activity. Although further in vivo and clinical studies are needed, these results suggested that NEAT1v1 switches the growth modality of liver cancer cell lines from MEK/ERK-dependent to AKT-dependent mode via SOD2 and regulates sensitivity to the molecular-targeted drugs independent of ER stress.

Establishment of cancer cell lines from rat hepatocholangiocarcinoma and assessment of the role of granulocyte-colony stimulating factor and hepatocyte growth factor in their growth, motility and survival

BACKGROUND/AIMS

Oval cells (OCs), putative hepatic stem cells, may give rise to liver cancers. We developed a carcinogenesis regimen, based upon induction of OC proliferation prior to carcinogen exposure. In our model, rats subjected to 2-acetylaminofluorene/ partial-hepatectomy followed by aflatoxin injection (APA regimen) developed well-differentiated hepatocholangiocarcinomas. The aim of this study was to establish and characterize cancer cell lines from this animal model.

METHODS

Cancer cells were cultured from animals sacrificed eight months after treatment, and single clones were selected. The established cell lines, named LCSCs, were characterized, and their tumorigenicity was assessed in vivo. The roles of granulocyte-colony stimulating factor (G-CSF) and hepatocyte growth factor (HGF) in LCSC growth, survival and motility were also investigated.

RESULTS

From primary tumors, six cell lines were developed. LCSCs shared with the primary tumors the expression of various OC-associated markers, including cMet and G-CSF receptor. In vitro, HGF conferred protection from death by serum withdrawal. Stimulation with G-CSF increased LCSC growth and motility, while the blockage of its receptor inhibited LCSC proliferation and migration.

CONCLUSIONS

Six cancer cell lines were established from our model of hepatocholangiocarcinoma. HGF modulated LCSC resistance to apoptosis, while G-CSF acted on LCSCs as a proliferative and chemotactic agent.