Phosphorylation of cMet tyrosine residues in murine ascitic hepatic cancer cell lines with different lymph node metastatic potentials

AXL and MET in Hepatocellular Carcinoma: A Systematic Literature Review

BACKGROUND

Multikinase inhibitors (MKIs) have been shown to improve survival in patients with hepatocellular carcinoma (HCC) compared with placebo. Distinct from other MKIs, cabozantinib has inhibitory activity for both AXL and MET. This review considers the literature elucidating the role of AXL and MET in HCC progression, treatment resistance, and immunomodulation. A systematic search of the PubMed database was conducted on November 16, 2020, and identified a total of 174 search results. A further 36 potentially relevant articles were identified based on the authors' knowledge. After initial screening by title/abstract, 159 underwent full-text screening and we identified 69 original research articles reporting empirical data from in vitro or in vivo models of HCC evaluating the effects of manipulating AXL or MET signaling on tumorigenic behavior.

SUMMARY

AXL expression is highly correlated with HCC progression and outcomes and has been reported to be involved in transforming growth factor-β and the regulation of PI3K/AKT, ERK/MAPK, and CCN proteins. MET protein expression is increased in HCC with the highest histological grade and has been reported to be involved in the regulation of PI3K/AKT, PLCγ/DAG/PKC, and MAPK/ERK signaling. Both AXL and MET are key regulators of sorafenib resistance in HCC. In terms of immunomodulation, there are data to indicate that AXL and MET interact with the immune components of the tumor microenvironment and promote tumorigenesis and treatment resistance. In addition, AXL was found to play a potential role in the development of a protumorigenic neutrophil phenotype in HCC. Combined inhibition of MET and programmed cell death protein resulted in additive reduction of HCC cell growth.

KEY MESSAGES

AXL and MET play key roles in HCC progression, treatment resistance, and immunomodulation. Continued development of drugs that target these receptor tyrosine kinases appears likely to represent a useful strategy to improve outcomes for patients with HCC.

Phosphoinositide-specific phospholipase C in normal human liver and in alcohol abuse

The phosphoinositide (PI) signal transduction pathway participates in liver metabolism. Abnormal activity or expression of PI-specific phospholipase C (PLC) enzymes has been described in different liver diseases. We resume the role of the PI metabolism in liver and PLC abnormalities in different liver diseases. Moreover, we present the results of PLC analyses in a normal human liver and an alcohol-damaged liver. PLC enzymes and the expression of the corresponding genes in liver biopsies from individuals deceased for complications of the alcoholic liver disease (ALD) at different stages compared with normal controls (deceased individuals with histologically normal livers without alcohol addiction anamnesis) were analyzed by using immunohistochemistry and molecular biology techniques. The expression panel of PLCs was described in normal and alcohol abuse liver. Our observations suggest that the regulation of PLC expression might be due to posttranscriptional events and that alcohol affects the epigenetic control of PLC expression belonging to PI signaling. We also describe the alternate expression of PLCB1 and PLCH1 genes in liver. Our results corroborate literature data suggesting that PLC enzymes are differently expressed in normal versus pathological liver, playing a role in the histopathogenesis of liver tissue damage. The expression and/or localization of selected PLC isoforms is especially affected in alcohol-related liver tissue histopathology. Our present observations confirm that the modulation of protein synthesis plays a role in the regulation of PLC enzymes. We also suggest that this modulation might act at the transcription level. Further studies are required to investigate related epigenetic mechanisms.

Anti-metastasis effect of fucoidan from Undaria pinnatifida sporophylls in mouse hepatocarcinoma Hca-F cells

Metastasis is one of the major causes of cancer-related death. It is a complex biological process involving multiple genes, steps, and phases. It is also closely connected to many biological activities of cancer cells, such as growth, invasion, adhesion, hematogenous metastasis, and lymphatic metastasis. Fucoidan derived from Undaria pinnatifida sporophylls (Ups-fucoidan) is a sulfated polysaccharide with more biological activities than other fucoidans. However, there is no information on the effects of Ups-fucoidan on tumor invasion and metastasis. We used the mouse hepatocarcinoma Hca-F cell line, which has high invasive and lymphatic metastasis potential in vitro and in vivo, to examine the effect of Ups-fucoidan on cancer cell invasion and metastasis. Ups-fucoidan exerted a concentration- and time-dependent inhibitory effect on tumor metastasis in vivo and inhibited Hca-F cell growth, migration, invasion, and adhesion capabilities in vitro. Ups-fucoidan inhibited growth and metastasis by downregulating vascular endothelial growth factor (VEGF) C/VEGF receptor 3, hepatocyte growth factor/c-MET, cyclin D1, cyclin-dependent kinase 4, phosphorylated (p) phosphoinositide 3-kinase, p-Akt, p-extracellular signal regulated kinase (ERK) 1/2, and nuclear transcription factor-κB (NF-κB), and suppressed adhesion and invasion by downregulating L-Selectin, and upregulating protein levels of tissue inhibitor of metalloproteinases (TIMPs). The results suggest that Ups-fucoidan suppresses Hca-F cell growth, adhesion, invasion, and metastasis capabilities and that these functions are mediated through the mechanism involving inactivation of the NF-κB pathway mediated by PI3K/Akt and ERK signaling pathways.