Yasuhiro Kidera

Reduction of lung metastasis, cell invasion, and adhesion in mouse melanoma by statin-induced blockade of the Rho/Rho-associated coiled-coil- containing protein kinase pathway

BackgroundMelanomas are highly malignant and have high metastatic potential; hence, there is a need for new therapeutic strategies to prevent cell metastasis. In the present study, we investigated whether statins inhibit tumor cell migration, invasion, adhesion, and metastasis in the B16BL6 mouse melanoma cell line.MethodsThe cytotoxicity of statins toward the B16BL6 cells were evaluated using a cell viability assay. As an experimental model, B16BL6 cells were intravenously injected into C57BL/6 mice. Cell migration and invasion were assessed using Boyden chamber assays. Cell adhesion analysis was performed using type I collagen-, type IV collagen-, fibronectin-, and laminin-coated plates. The mRNA levels, enzyme activities and protein levels of matrix metalloproteinases (MMPs) were determined using RT-PCR, activity assay kits, and Western blot analysis, respectively; the mRNA and protein levels of vary late antigens (VLAs) were also determined. The effects of statins on signal transduction molecules were determined by western blot analyses.ResultsWe found that statins significantly inhibited lung metastasis, cell migration, invasion, and adhesion at concentrations that did not have cytotoxic effects on B16BL6 cells. Statins also inhibited the mRNA expressions and enzymatic activities of matrix metalloproteinases (MMPs). Moreover, they suppressed the mRNA and protein expressions of integrin α2, integrin α4, and integrin α5 and decreased the membrane localization of Rho, and phosphorylated LIM kinase (LIMK) and myosin light chain (MLC).ConclusionsThe results indicated that statins suppressed the Rho/Rho-associated coiled-coil-containing protein kinase (ROCK) pathways, thereby inhibiting B16BL6 cell migration, invasion, adhesion, and metastasis. Furthermore, they markedly inhibited clinically evident metastasis. Thus, these findings suggest that statins have potential clinical applications for the treatment of tumor cell metastasis.

Risk Factors for Cisplatin-Induced Nephrotoxicity and Potential of Magnesium Supplementation for Renal Protection

Background Nephrotoxicity remains a problem for patients who receive cisplatin chemotherapy. We retrospectively evaluated potential risk factors for cisplatin-induced nephrotoxicity as well as the potential impact of intravenous magnesium supplementation on such toxicity. Patients and Methods We reviewed clinical data for 401 patients who underwent chemotherapy including a high dose (≥60 mg/m2) of cisplatin in the first-line setting. Nephrotoxicity was defined as an increase in the serum creatinine concentration of at least grade 2 during the first course of cisplatin chemotherapy, as assessed on the basis of National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. The severity of nephrotoxicity was evaluated on the basis of the mean change in the serum creatinine level. Magnesium was administered intravenously to 67 patients (17%). Results Cisplatin-induced nephrotoxicity was observed in 127 patients (32%). Multivariable analysis revealed that an Eastern Cooperative Oncology Group performance status of 2 (risk ratio, 1.876; P = 0.004) and the regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) (risk ratio, 1.357; P = 0.047) were significantly associated with an increased risk for cisplatin nephrotoxicity, whereas intravenous magnesium supplementation was associated with a significantly reduced risk for such toxicity (risk ratio, 0.175; P = 0.0004). The development of hypomagnesemia during cisplatin treatment was significantly associated with a greater increase in serum creatinine level (P = 0.0025). Magnesium supplementation therapy was also associated with a significantly reduced severity of renal toxicity (P = 0.012). Conclusions A relatively poor performance status and the regular use of NSAIDs were significantly associated with cisplatin-induced nephrotoxicity, although the latter association was marginal. Our findings also suggest that the ability of magnesium supplementation to protect against the renal toxicity of cisplatin warrants further investigation in a prospective trial.

Mangiferin induces apoptosis by suppressing Bcl-xL and XIAP expressions and nuclear entry of NF-κB in HL-60 cells

Mangiferin, 1,3,6,7-tetrahydroxyxanthone-C2-β-d-glucoside (C-glucosylxanthone), is a xanthone derivative that is widely distributed in higher plants. Recently, mangiferin was found to exhibit potential antitumor effects. However, the molecular mechanisms of this effect have not been elucidated. In the present study, we attempt to clarify the mechanism of mangiferin-induced apoptosis in the human acute myeloid leukemia cell line HL-60; mangiferin was found to induce apoptosis. We also observed a concurrent increase in caspase-3 activity and DNA fragmentation. Furthermore, on examining the survival signals expressed during apoptotic induction, we observed that mangiferin caused a remarkable decrease in the nuclear entry of NF-κB p65. However, there were no changes in the expression of other survival signals, such as extracellular signal-regulated kinase 1/2, protein kinase B, and p38 mitogenactivated protein kinase. In addition, mangiferin suppressed the expressions of Bcl-xL and XIAP; however, we did not note any changes in the levels of Bcl-2, Bax, and Bim. These results indicate that mangiferin induces apoptosis by suppressing NF-κB activation and expressions of Bcl-xL and XAIP. These findings suggest that mangiferin may be useful as an anticancer agent and can be used in combination therapy with other anticancer drugs for the treatment of acute myeloid leukemia.

Blockade of the Ras/MEK/ERK and Ras/PI3K/Akt pathways by statins reduces the expression of bFGF, HGF, and TGF-β as angiogenic factors in mouse osteosarcoma.

The tumor microenvironment plays a critical role in modulating malignant behavior and can dramatically influence cancer treatment strategies. We investigated whether statins inhibit the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), and transforming growth factor-β (TGF-β) mRNA in the mouse osteosarcoma cell line LM8. We found that statins significantly inhibited mRNA expressions of bFGF, HGF, and TGF-β, and bFGF, HGF, and TGF-β secretions at concentrations that did not have antiproliferative effects on LM8 cells, but had no effect on the mRNA expression and secretion of VEGF. The inhibition of bFGF, HGF, and TGF-β mRNA expression, and bFGF, HGF, TGF-β secretions was reversed when geranylgeranyl pyrophosphate (GGPP), an intermediate in the mevalonate pathway, was used in combination with statins. Furthermore, statins reduced the membrane localization of K-Ras, phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), and phosphorylated Akt. Our research indicates that statins inhibit GGPP biosynthesis in the mevalonate pathway, and then inhibit signal transduction in the Ras/ERK and Ras/Akt pathways, thereby inhibiting bFGF, HGF, TGF-β expression in LM8 cells. These results suggest that statins are potentially useful as anti-angiogenic agents for the treatment of osteosarcoma.

Dimethylfumarate inhibits tumor cell invasion and metastasis by suppressing the expression and activities of matrix metalloproteinases in melanoma cells

NF‐κB acts as a signal transducer during tumor progression, cell invasion, and metastasis. Dimethylfumarate (DMF) is reported to inhibit tumor necrosis factor‐α‐induced nuclear entry of NF‐κB/p65. However, only a few reports suggest that DMF inhibits tumor metastasis; also the molecular mechanisms underlying the inhibition of metastasis are poorly understood. We investigated the inhibition of tumor invasion and metastasis by DMF in a melanoma cell line, B16BL6. DMF inhibited B16BL6 cell invasion and metastasis by suppressing the expression and activities of MMPs. DMF also inhibited the nuclear entry of NF‐κB/p65, thus inhibiting B16BL6 cell invasion and metastasis. These results suggest that DMF is potentially useful as an anti‐metastatic agent for the treatment of malignant melanoma.

Macrophage inflammatory protein‐1α induces osteoclast formation by activation of the MEK/ERK/c‐Fos pathway and inhibition of the p38MAPK/IRF‐3/IFN‐β pathway

Multiple myeloma (MM) is a bone disease that affects many individuals. It was recently reported that macrophage inflammatory protein (MIP)‐1α is constitutively secreted by MM cells. MIP‐1α causes bone destruction through the formation of osteoclasts (OCs). However, the molecular mechanism underlying MIP‐1α‐induced OC formation is not well understood. In the present study, we attempted to clarify the mechanism whereby MIP‐1α induces OC formation in a mouse macrophage‐like cell line comprising C7 cells. We found that MIP‐1α augmented OC formation in a concentration‐dependent manner; moreover, it inhibited IFN‐β and ISGF3γ mRNA expression, and IFN‐β secretion. MIP‐1α increased the expressions of phosphorylated ERK1/2 and c‐Fos and decreased those of phosphorylated p38MAPK and IRF‐3. We found that the MEK1/2 inhibitor U0126 inhibited OC formation by suppressing the MEK/ERK/c‐Fos pathway. SB203580 induced OC formation by upregulating c‐fos mRNA expression, and SB203580 was found to inhibit IFN‐β and IRF‐3 mRNA expressions. The results indicate that MIP‐1α induces OC formation by activating and inhibiting the MEK/ERK/c‐Fos and p38MAPK/IRF‐3 pathways, respectively, and suppressing IFN‐β expression. These findings may be useful in the development of an OC inhibitor that targets intracellular signaling factors. J. Cell. Biochem. 111: 1661–1672, 2010.

Nitrogen-containing bisphosphonate, YM529/ONO-5920, inhibits tumor metastasis in mouse melanoma through suppression of the Rho/ROCK pathway

The small GTPases of the Ras and Rho families are widely involved in tumorigenesis and metastasis. We recently showed that YM529/ONO-5920, a new developed bisphosphonate, inhibits the mevalonate pathway, is required for the prenylation of the small GTPases. In this study, we investigated whether YM529/ONO-5920 inhibits tumor cell migration, invasion, adhesion, and metastasis in B16BL6 cells, a mouse melanoma cell line. It was found that YM529/ONO-5920 significantly inhibited lung metastasis, cell migration, invasion, and adhesion at concentrations that did not show anti-proliferative effects on B16BL6 cells. YM529/ONO-5920 also inhibited the expression of matrix metalloproteinases (MMPs) and very late antigens (VLAs). Furthermore, YM529/ONO-5920 suppressed Rho activation, but not activation of Ras. The results indicate that YM529/ONO-5920 suppresses the Rho/ROCK pathways, thereby inhibiting B16BL6 cell migration, invasion, adhesion and metastasis. These findings suggest that YM529/ONO-5920 has potential clinical applications for the treatment of tumour cell metastasis.