Vitamin K2-induced antitumor effects via cell-cycle arrest and apoptosis in gastric cancer cell lines

Abstract

Vitamin K2 (VK2) has a growth inhibitory effect on various types of cancer cells in vitro, and its efficacy has been demonstrated in clinical applications in a number of patients with leukemia and hepatocellular carcinoma. In this study, the effect of cell growth inhibition and apoptosis induction and the concomitant use of an anticancer agent by VK2 (menaquinone: MK4), on gastric cancer cell lines were examined. When 4 kinds of gastric cancer cells (KATO III, MKN7, MKN74 and FU97) were exposed to MK4, the cell growth was inhibited in an MK4 dose-dependent manner. Morphologically, apoptosis induced by MK4 was recognized in FU97, but only a slight number of apoptotic images was recognized in other cell lines. On the contrary, in all the cell lines, the percentage of APO2.7 positive cells increased significantly in the MK4-treated group as compared to the controls. Caspase-3 activity increased significantly in KATO III and FU97 as compared to the controls, while no significant differences were noted in MKN7 or MKN74. Moreover, in all the cell lines, the percentage of G0/G1-phase cells (~70% in KATO III and FU97, and ≥80% in MKN7 and MKN74) increased in comparison to the controls, suggesting that cellcycle arrest had occurred. All of the gastric cancer cell lines were given MK4 in different concentrations and two kinds of anticancer agent, with the result that cell growth was inhibited by the anticancer agent in a dose-dependent manner when it was given with MK4 in concentrations of up to 10 μM. In conclusion, our results demonstrate that the effect of MK4 on apoptosis and cell-cycle arrest differs in differentiated (MKN7, MKN74) and undifferentiated (KATO III, FU97) gastric cancer cell lines, and that MK4 alone or with anticancer agents has an antitumor effect on gastric cancer cell lines.

Growth inhibitory effects of vitamin K2 on colon cancer cell lines via different types of cell death including autophagy and apoptosis

“…In our previous studies, we observed morphologically typical apoptosis in various types of leukemia cell lines including the HL-60 leukemia cell line, a primary culture system of leukemia cells derived from patients with acute leukemia (6), a small cell lung cancer line A547 (8), and a gastric cancer cell line FU97 (9), but we did not note typical findings of apoptosis in any cell lines of the other solid cancer (9,11). Moreover, the percentage of APO2.7 positive cells, an indicator of apoptosis, also showed a significant increase in gastric cancer cell lines other than FU97; however, the percentage tended to increase in three types of cholangiocellular carcinoma cell lines, which was not a statistically significant difference (9). In the present study, we performed an immunoblotting assay using a cleaved caspase-3 monoclonal antibody to confirm the activation of caspase-3 in PMCO1.…”

“…Although detailed information concerning the mechanisms of the cell growth inhibitory effects of MK4 are not completely understood, it is evident from our previous in vitro studies that the effect is at least partly based on the induction of cellcycle arrest, differentiation, and apoptosis (6)(7)(8)(9). In addition, in apoptosis-resistant leukemia cell lines and cholangiocarcinoma cell lines, it was shown that autophagy-mediated cell death, i.e., type II programmed cell death, is one of the mechanisms of MK4 inhibiting cell growth (10,11).…”

Inhibition of matrix metalloproteinase expression by menatetrenone, a vitamin K2 analogue

“…Previous studies have revealed that VK2 are involved not only in Á-carboxylation of proteins but also in the Á-carboxylation independent function, thus suggesting that VK2 possess both Á-carboxylation-dependent and -independent actions (26). As an example of the Á-carboxylationindependent action of VK2, vitamin Ks has been demonstrated to have an anti-proliferative effect in many types of cancer cells including HCC (14,15,18,20,24,(26)(27)(28)(29)(30). In addition to anti-proliferative effects, VK2 also suppresses the invasion of HCC cells (18).…”

Vitamin K2 as a Chemotherapeutic Agent for Treating Ovarian Cancer

“…Inhibition of cancerous cell growth and induction of apoptosis by vitamin K2 has subsequently been observed in a variety of human cancer cell lines, including liver (Nishikawa et al, 1995;Otsuka et al, 2004), pancreatic (Shibayama-Imazu et al, 2003), ovarian (Shibayama-Imazu et al, 2003, lung (Yoshida et al, 2003;Yokoyama et al, 2005), stomach (Tokita et al, 2006), breast (Wu et al, 1993), and leukocyte (Yaguchi, 1997). The growth-inhibitory effects of vitamin K2 on various human cancer cell lines are listed in Table 1.…”