Effect of isoform-specific HIF-1α and HIF-2α antisense oligonucleotides on tumorigenesis, inflammation and fibrosis in a hepatocellular carcinoma mouse model

Abstract

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. For advanced HCC, there is still an unmet need for more effective therapeutic strategies. HCC is typically associated with hypoxia and the hypoxiainducible factor (HIF) regulatory pathway plays an important role in HCC development and progression. Therefore, we investigated the therapeutic potential of isoformspecific HIF-1α and HIF-2α antisense oligonucleotides (ASOs), along with their effect on the inflammatory and fibrotic component of the tumor microenvironment (TME), in an experimental HCC mouse model. Based on its efficacy and safety, a dosage regimen of 20 mg/kg intraperitoneal injection of HIFα ASO twice per week was selected for further investigation in a preventive and therapeutic setting in a N,Ndiethylnitrous amide (DEN)-induced HCC mouse model. DEN administration resulted in 100% tumor formation and HIFα ASO administration led to effective and selective hepatic downregulation of its target genes. HIFα ASO treatment had no effect on tumor numbers, but even enhanced the increased hepatic expression of HCC tumor markers, α-fetoprotein and glypican-3, compared to scrambled control ASO treatment in HCC mice. Especially HIF-1α ASO treatment resulted in an enhanced increase of monocytes and monocyte-derived macrophages in the liver and an enhanced hepatic upregulation of inflammatory markers. Both HIFα ASOs aggravated liver fibrosis in HCC mice compared to scrambled ASO treatment. The observed effects of our dosing regimen for HIF-1α and HIF-2α ASO treatment in the DEN-induced HCC mouse model discourage the use of HIFα isoforms as targets for the treatment of HCC.

Hypoxia, Hypoxia-Inducible Factors and Liver Fibrosis

“…As a final comment, one should note that the mentioned involvement of HIF2α activation in pro-fibrogenic progression of CLD has already led to the use in preclinical studies of specifically designed therapeutic strategies. The first study to be mentioned employed in vivo administration of isoform-specific HIF-1α and HIF-2α antisense oligonucleotides (ASOs) in a murine model of diethyl-nitrosamine (DEN)-induced CLD and HCC [ 133 ]. This study revealed that both the ASOs employed did not prevent but rather enhanced inflammation and fibrosis, suggesting that directly targeting HIF2α in the liver may not represent the right approach.…”

The Gut–Liver Axis in Chronic Liver Disease: A Macrophage Perspective

“…However, which cells contribute to the TAM pool has only partly been unraveled. We and others showed that HCC is characterized by KC depletion and a simultaneous rise of MoMFs, at least in mice [ 60 , 362 , 363 ]. However, we also showed that, in addition to the widely accepted contribution of infiltrating MoMFs to the TAM pool in HCC, KCs also express markers that are typically associated with TAMs [ 128 ].…”

Liver Cancer: Therapeutic Challenges and the Importance of Experimental Models

“…For example, DEN model is a commonly used model since it is effective in producing tumors with an incidence of 100% of the study subjects; this model generates fibrogenesis and loss weight in experimental animals and also allows the presence of inflammatory infiltrate and proinflammatory cytokines, yet a constant and consecutive weekly application of DEN is necessary for 15 weeks, starting from 5 weeks of age of the animals under study. It is important to mention that it is difficult to establish the onset of the appearance of carcinogenic damage and, therefore, the analysis of the events that occur in the early stages of the disease [ 41 ].…”

“…For example, DEN model is a commonly used model since it is effective in producing tumors with an incidence of 100% of the study subjects; this model generates fibrogenesis and loss weight in experimental animals and also allows the presence of inflammatory infiltrate and proinflammatory cytokines, yet a constant and consecutive weekly application of DEN is necessary for 15 weeks, starting from 5 weeks of age of the animals under study. It is important to mention that it is difficult to establish the onset of the appearance of carcinogenic damage and, therefore, the analysis of the events that occur in the early stages of the disease [41]. e CCl 4 model allows HCC implementation through fibrosis and cirrhosis generation and the first neoplastic lesions that would become part of adenomas and carcinomas in different tissues; this model also offers the advantage of analyzing genotoxic events at the hepatic level and liver fat accumulation as well as chronic progressive nephropathy.…”