Down-regulation of hepatic expression of GHR/STAT5/IGF-1 signaling pathway fosters development and aggressiveness of HCV-related hepatocellular carcinoma: Crosstalk with Snail-1 and type 2 transforming growth factor-beta receptor

Abstract

Background and aims: So far, few clinical trials are available concerning the role of growth hormone receptor (GHR)/signal transducer and activator of transcription 5 (STAT5)/insulin like growth factor-1 (IGF-1) axis in hepatocarcinogenesis. The aim of this study was to evaluate the hepatic expression of GHR/STAT5/IGF-1 signaling pathway in hepatocellular carcinoma (HCC) patients and to correlate the results with the clinico-pathological features and disease outcome. The interaction between this signaling pathway and some inducers of epithelial-mesenchymal transition (EMT), namely Snail-1 and type 2 transforming growth factor-beta receptor (TGFBR2) was studied too.

Material and methods: A total of 40 patients with HCV-associated HCC were included in this study. They were compared to 40 patients with HCV-related cirrhosis without HCC, and 20 healthy controls. The hepatic expression of GHR, STAT5, IGF-1, Snail-1 and TGFBR2 proteins were assessed by immunohistochemistry.

Results: Compared with cirrhotic patients without HCC and healthy controls, cirrhotic patients with HCC had significantly lower hepatic expression of GHR, STAT5, and IGF-1proteins. They also displayed significantly lower hepatic expression of TGFBR2, but higher expression of Snail-1 versus the non-HCC cirrhotic patients and controls. Serum levels of alpha-fetoprotein (AFP) showed significant negative correlations with hepatic expression of GHR (r = -0.31; p = 0.029) and STAT5 (r = -0.29; p = 0.04). Hepatic expression of Snail-1 also showed negative correlations with GHR, STAT5, and IGF-1 expression (r = -0.55, p = 0.02; r = -0.472, p = 0.035, and r = -0.51, p = 0.009, respectively), whereas, hepatic expression of TGFBR2 was correlated positively with the expression of all these proteins (r = 0.47, p = 0.034; 0.49, p = 0.023, and r = 0.57, p<0.001, respectively). Moreover, we reported that decreased expression of GHR was significantly associated with serum AFP level>100 ng/ml (p = 0.048), increased tumor size (p = 0.02), vascular invasion (p = 0.002), and advanced pathological stage (p = 0.01). Similar significant associations were found between down-regulation of STAT5 expression and AFP level > 100 ng/ml (p = 0.006), vascular invasion (p = 0.009), and advanced tumor stage (p = 0.007). Also, attenuated expression of IGF-1 showed a significant association with vascular invasion (p < 0.001). Intriguingly, we detected that lower expression of GHR, STAT5 and IGF-1 were considered independent predictors for worse outcome in HCC.

Conclusion: Decreased expression of GHR/STAT5/IGF-1 signaling pathway may have a role in development, aggressiveness, and worse outcome of HCV-associated HCC irrespective of the liver functional status. Snail-1 and TGFBR2 as inducers of EMT may be key players. However, large prospective multicenter studies are needed to validate these results.

Fig 1

(a-i): Hepatic expression of GHR, STAT5, and IGF-1 proteins in the study groups. GHR expression: a)in healthy control: b) in cirrhotic patients; c) in HCC patients; (predominantly cytoplasmic); STAT5 expression: d) in healthy control; e) in cirrhotic patients; f) in HCC patients (cytoplasmic/nuclear) IGF-1 expression: g)in healthy controls; h) in cirrhotic patients; i) in HCC patients (predominantly cytoplasmic). Magnification 200 X scale bar 100 μm. HCC: hepatocellular carcinoma; GHR: growth hormone receptor; STAT5: signal transducer and activator of transcription5; IGF-1: insulin like growth factor-1.

Fig 2

(a-f): Hepatic expression of Snail-1 and TGFBR2 proteins in the study groups. Snail-1expression: a) in healthy control: b) in cirrhotic patients; c) in HCC patients; (predominantly cytoplasmic); TGFBR2 expression: d) in healthy control; e) in cirrhotic patients; f) in HCC patients (predominantly nuclear). Magnification 200 X scale bar 100 μm. HCC: hepatocellular carcinoma; TGFBR2: type 2 transforming growth factor-beta receptor.

Fig 3

(a-n): Examples of expression of GHR, STAT5, IGF-1, Snail-1 and TGFBR2 in a variety of stromal cells of TME in HCC and cirrhotic patients. GHR: growth hormone receptor, STAT5: signal transducer and activator of transcription5; IGF-1: insulin like growth factor-1; TGFBR2: type 2 transforming growth factor-beta receptor; TME: tumor microenvironment; HCC: hepatocellular carcinoma. *: Images are presented at 20X magnification power with 200X zoom in boxes.