Vitamin K₂ Inhibits the Growth of Hepatocellular Carcinoma via Decrease of Des-Gamma-Carboxy Prothrombin

Abstract

Background: Des-γ-carboxy prothrombin (DCP) is a serum protein produced by hepatocellular carcinoma (HCC) cells in the absence of vitamin K. Serum and tissue DCP expressions are thought to reflect the biological malignant potential of HCC. Hence, we aimed to examine the efficacy of vitamin K₂ on the production of DCP as well as tumor cell growth and invasion. Methods: Cell growth and viability were evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. The in vivo efficacy of vitamin K₂ was examined in nude mice bearing HCC cells. A 24-well transwell chamber was used to evaluate the motility and invasive ability of HCC cells. Levels of DCP in supernatant of cultures and in serum of mice were measured using an electrochemiluminescence immunoassay method. Western blot and immunohistochemical analysis were employed to evaluate the expression of DCP in HCC. Results: Vitamin K₂ (2–40 μM) significantly decreased the levels of DCP production in supernatant of PLC/PRF/5 and HepG2 cells and in serum of nude mice bearing HCC xenografts. The inhibition of DCP was also observed using the assays of Western blot analysis in HCC cultures and immunohistochemical analysis in HCC xenografts in mice. As a result of administration of vitamin K₂, the capacity of HCC growth was inhibited and the invasion and migration of tumor cells were decreased. Furthermore, the inhibitory effects of HCC growth were also observed in vivo and the sensitivitywas well correlated with the decrease of DCP in the serum of mice. Conclusion: Vitamin K₂ might suppress the growth and invasion of HCC cells via decrease of DCP.

Des-γ-carboxy prothrombin and c-Met were concurrently and extensively expressed in hepatocellular carcinoma and associated with tumor recurrence

“…Recent studies by the current authors and other researchers found that des-γ-carboxy prothrombin (DCP), an abnormal cytokine secreted by HCC cells, was involved in the activation and regulation of downstream pathways of the c-Met signaling system in vitro and in animal studies (17)(18)(19)(20). Thus, whether or not DCP and c-Met are co-expressed in human HCC and whether their co-expression is correlated with tumor recurrence are questions of great interest.…”

Des-γ-Carboxy Prothrombin (DCP) as a Potential Autologous Growth Factor for the Development of Hepatocellular Carcinoma

“…The level of DCP in supernatant of cell culture was determined by an electrochemiluminescence immunoassay. The results showed that Vitamin K 2 (2-40 μM) significantly decreased DCP production [43]. Importantly, the effect of vitamin K 2 on DCP production was observed in nude mice bearing HCC xenografts.…”

“…Importantly, the effect of vitamin K 2 on DCP production was observed in nude mice bearing HCC xenografts. As a result of vitamin K 2 administration, the capacity of HCC xenografts was obviously inhibited [43]. In clinical studies, Ishizuka et al evaluated the effects of menatetrenone, which is a vitamin K 2 analog, on recurrence of hepatocellular carcinoma after surgical resection.…”

c-Met-Akt pathway-mediated enhancement of inhibitory c-Raf phosphorylation is involved in vitamin K1 and sorafenib synergy on HCC growth inhibition

“…The K vitamins have been shown to possess weak anti-HCC growth activity in vitro and in animal models. [8][9][10] Recently it has also been reported that vitamin K2 can decrease HCC recurrences post-surgical resection 32 and may even inhibit human hepatocarcinogenesis. 33 Sorafenib, a recently FDA-approved multi-kinase inhibitor for phosphorylation by vitamin K1 plus sorafenib combination and PKA inhibitor H89 had no effect on vitamin K1 plus sorafenib inhibition of Raf kinase activity.…”