Thioredoxin interacting protein promotes invasion in hepatocellular carcinoma

// Aysim Gunes 1 , Ezgi Bagirsakci 1 , Evin Iscan 1 , Gulcin Cakan-Akdogan 1 , Umut Aykutlu 2 , Serif Senturk 1 , Gunes Ozhan 1 , Esra Erdal 1 , Deniz Nart 2 , Funda Yilmaz Barbet 2 and Nese Atabey 1 1 Izmir Biomedicine and Genome Center, Izmir, 35340 Balcova, Turkey 2 Ege University, Faculty of Medicine, Department of Pathology, Izmir, 35040 Bornova, Turkey Correspondence to: Nese Atabey, email: nese.atabey@ibg.edu.tr Keywords: HCC; oxidative stress; TXNIP; EMT; metastasis Received: January 08, 2018      Accepted: November 16, 2018      Published: December 07, 2018 ABSTRACT Background: Considerable evidence suggests that oxidative stress plays an essential role in the progression of hepatocellular carcinoma (HCC). While acquired resistance to oxidative stress is the main driver of aggressive cell phenotype, the underlying mechanisms remain unknown. Here, we tested the hypothesis that elevated expression of Thioredoxin-interacting protein (TXNIP) is a main regulator of the aggressive phenotype in HCC. Materials and Methods: To test this hypothesis, we measured TXNIP expression levels in 11 HCC cell lines by qPCR and western blotting. In addition, 80 pairs of HCC tissues and matched liver tissues of 73 cases, as well as 11 normal liver tissue samples were examined by immunohistochemistry. Besides, TXNIP expression levels were analyzed by Oncomine Platform in seven independent microarray datasets. Finally, the functional role of TXNIP in HCC was investigated in vitro and in vivo by silencing and overexpression studies. Results: Our results show that TXNIP expression is significantly increased in HCC compared to non-tumor counterparts ( p < 0.0001) as well as to normal ( p < 0.0001) and cirrhotic ( p < 0.0001) liver tissues. Moreover, stable overexpression of TXNIP in HCC cells (i) significantly increases ROS levels, (ii) induces EMT phenotype, (iii) increases motility, invasion and 3D branching tubulogenesis, (iv) decreases apoptosis, and (v) elevates in vivo metastasis in zebrafish embryos. Finally, we identify sinusoidal/stromal and cytoplasmic TXNIP staining patterns as risk factors for intrahepatic vascular invasion (p:0.0400). Conclusion: Our results strongly suggest that overexpression of TXNIP has a pivotal role in HCC progression by inducing cell survival, invasion, and metastasis.