Vitamin K enhancement of Sorafenib-mediated HCC cell growth inhibition in vitro and in vivo

Department of Medical Oncology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
International Journal of Cancer (Impact Factor: 5.09). 12/2010; 127(12):2949-58. DOI: 10.1002/ijc.25498
Source: PubMed


The multikinase inhibitor sorafenib is the first oral agent to show activity against human hepatocellular carcinoma (HCC). Apoptosis has been shown to be induced in HCC by several agents, including sorafenib as well as by the naturally occurring K vitamins (VKs). As few nontoxic agents have activity against HCC growth, we evaluated the activity of sorafenib and VKs, both independently and together on the growth of HCC cells in vitro and in vivo. We found that when VK was combined with sorafenib, the concentration of sorafenib required for growth inhibition was substantially reduced. Conversely, VK enhanced sorafenib effects in several HCC cell lines on growth inhibition. Growth could be inhibited at doses of VK plus sorafenib that were ineffective with either agent alone, using vitamins K1, K2 and K5. Combination of VK1 plus sorafenib induced apoptosis on FACS, TUNEL staining and caspase activation. Phospho-extracellular signal-regulated kinase (ERK) levels were decreased as was myeloid cell leukemia sequence 1 (Mcl-1), an ERK target. Sorafenib alone inhibited growth of transplantable HCC in vivo. At subeffective sorafenib doses in vivo, addition of VK1 caused major tumor regression, with decreased phospho-ERK and Mcl-1 staining. Thus, combination of VK1 plus sorafenib strongly induced growth inhibition and apoptosis in rodent and human HCC and inhibited the RAF/mitogen-activated protein kinase kinase/ERK pathway. VK1 alone activated PKA, a mediator of inhibitory Raf phosphorylation. Thus, each agent can antagonize Raf: sorafenib as a direct inhibitor and VK1 through inhibitory Raf phosphorylation. As both agents are available for human use, the combination has potential for improving sorafenib effects in HCC.

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Available from: Terry Hyslop
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    • "Regarding the different doses of VK1 used in this study, concentrations ranging from 10 í µí¼‡M to 200 í µí¼‡M can be considered pharmacological since normal serum levels of VK1 were found to be approximately 0.61 ng/mL. Yet, VK1 appears to be without toxicity and studies performed in humans established that mega doses of VK1 (up to 1000 mg orally daily) were used without side effects in patients with HCC [36]. Additionally, other studies clearly indicated that VK1 alone did not alter P-ERK levels, except at very high concentrations starting from 100 í µí¼‡M, the same concentrations needed to exert the anticancer effects seen in our human colon cancer cells [37] "
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    ABSTRACT: Vitamin K1 has been demonstrated as having anticancer potentiality mainly in liver cancer cells. Beyond the reported mechanisms of cancer inhibition (cell cycle arrest and induction of apoptosis), a possible control by vitamin K1 on molecules affecting cell growth could be hypothesized. In the literature, few (if any) data are available on its antitumor effects on colon cancer cells. Therefore, the aims of the study were to investigate in three differently graded human colon cancer cell lines (Caco-2, HT-29, and SW480) the effects of increasing concentrations of vitamin K1 (from 10 μM to 200 μM) administered up to 72 h on (1) cell proliferation, (2) apoptosis with the possible involvement of the MAPK pathway, and (3) polyamine biosynthesis. Vitamin K1 treatment caused a significant antiproliferative effect and induced apoptosis in all the cell lines, with the involvement of the MAPK pathway. A concomitant and significant decrease in the polyamine biosynthesis occurred. This is the first study demonstrating a significant polyamine decrease in addition to the antiproliferative and proapoptotic effects following vitamin K1 administration to colon cancer cell lines. Therapeutically, combinations of vitamin K1 with polyamine inhibitors and/or analogues may represent a suitable option for chemoprevention and/or treatment in future strategies for colorectal cancer management.
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    • "HCC typically arises on the basis of cirrhosis and responds poorly to conventional cytotoxic chemotherapy [31]. This has led to a search for novel approaches for molecular targeted therapy. "
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    Full-text · Article · Jan 2014 · Molecular Cancer
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    • "These studies thus suggest that the intake of VK2 may be beneficial in preventing the progression of prostate cancer. Moreover, VK2 is also shown to enhance the chemotherapeutic efficacy of conventional anticancer drug Sorafenib in hepatocellular carcinoma [18]. Unlike its synthetic counterpart, vitamin k3, there are no known side effects associated with ingestion of high doses of VK2 [19]. "
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    ABSTRACT: In recent years, several studies have shown that vitamin k2 (VK2) has anticancer activity in a variety of cancer cells. The antitumor effects of VK2 in prostate cancer are currently not known. In the present study, we sought to characterize the anticancer potential of VK2 in both androgen-dependent and -independent prostate cancer cells. Our investigations show that VK2 is able to suppress viability of androgen-dependent and androgen-independent prostate cancer cells via caspase-3 and -8 dependent apoptosis. We also show that VK2 treatment reduces androgen receptor expression and PSA secretion in androgen-dependent prostate cancer cells. Our results also implicate VK2 as a potential anti-inflammatory agent, as several inflammatory genes are downregulated in prostate cancer cells following treatment with VK2. Additionally, AKT and NF-kB levels in prostate cancer cells are reduced significantly when treated with VK2. These findings correlated with the results of the Boyden chamber and angiogenesis assay, as VK2 treatment reduced cell migration and angiogenesis potential of prostate cancer cells. Finally, in a nude mice model, VK2 administration resulted in significant inhibition of both androgen-dependent and androgen-independent tumor growth. Overall, our results suggest that VK2 may be a potential therapeutic agent in the treatment of prostate cancer.
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