Selectively Enhanced Electrocatalytic Oxygen Evolution within Nanoscopic Channels Fitting a Specific Reaction Intermediate for Seawater Splitting.

Abundant availability of seawater grants economic and resource-rich benefits to water electrolysis technology requiring high-purity water if undesired reactions such as chlorine evolution reaction (CER) competitive to oxygen evolution reaction (OER) are suppressed. Inspired by a conceptual computational work suggesting that OER is kinetically improved via a double activation within 7 Å-gap nanochannels, RuO2 catalysts are realized to have nanoscopic channels at 7, 11, and 14 Å gap in average (dgap ), and preferential activity improvement of OER over CER in seawater by using nanochanneled RuO2 is demonstrated. When the channels are developed to have 7 Å gap, the OER current is maximized with the overpotential required for triggering OER minimized. The gap value guaranteeing the highest OER activity is identical to the value expected from the computational work. The improved OER activity significantly increases the selectivity of OER over CER in seawater since the double activation by the 7 Å-nanoconfined environments to allow an OER intermediate (*OOH) to be doubly anchored to Ru and O active sites does not work on the CER intermediate (*Cl). Successful operation of direct seawater electrolysis with improved hydrogen production is demonstrated by employing the 7 Å-nanochanneled RuO2 as the OER electrocatalyst.

Effect of pain scrambler therapy on antineuralgic pain and quality of life after shingles.

[Purpose] The aim of this study was to analyze the effect of pain scrambler therapy on antineuralgic pain and quality of life after shingles. [Subjects and Methods] Daily pain scrambler therapy was administered to antineuralgic patients for 10 days, with each session lasting approximately 40 minutes. Pain was measured using the visual analog scale, and quality of life was assessed with the short form 36-item (SF-36). [Results] After10 sessions of pain scrambler therapy, pain had significantly reduced compared to that experienced prior to treatment. The quality of life had also improved following completion of 10 treatment sessions. [Conclusion] Pain scrambler therapy decreased patients' post-shingles antineuralgic pain and improved quality of life.

PBI-05204, a supercritical CO2 extract of Nerium oleander, inhibits growth of human pancreatic cancer via targeting the PI3K/mTOR pathway.

Introduction Oleandrin, a cardiac glycoside, exerts strong anti-proliferative activity against various human malignancies in in vitro cells. Here, we report the antitumor efficacy of PBI-05204, a supercritical C02 extract of Nerium oleander containing oleandrin, in a human pancreatic cancer Panc-1 orthotopic model. Results While all the control mice exhibited tumors by the end of treatment, only 2 of 8 mice (25%) treated for 6 weeks with PBI-05204 (40 mg/kg) showed dissectible tumor at the end of the treatment period. The average tumor weight (222.9 ± 116.9 mg) in mice treated with PBI-05204 (20 mg/kg) was significantly reduced from that in controls (920.0 ± 430.0 mg) (p < 0.05). Histopathologic examination of serial sections from each pancreas with no dissectible tumor in the PBI-05204 (40 mg/kg) treated group showed that the pancreatic tissues of 5/6 mice were normal while the remaining mouse had a tumor the largest diameter of which was less than 2.3 mm. In contrast, while gemcitabine alone did not significantly reduce tumor growth, PBI-05204 markedly enhanced the antitumor efficacy of gemcitabine in this particular model. Ki-67 staining was reduced in pancreatic tumors from mice treated with PBI-05204 (20 mg/kg) compared to that of control, suggesting that PBI-05204 inhibited the proliferation of the Panc-1 tumor cells. PBI-05204 suppressed expression of pAkt, pS6, and p4EPB1 in a concentration-dependent manner in both Panc-1 tumor tissues and human pancreatic cancer cell lines, implying that this novel botanical drug exerts its potent antitumor activity, at least in part, through down-regulation of PI3k/Akt and mTOR pathways.

Gain of glucose-independent growth upon metastasis of breast cancer cells to the brain.

Breast cancer brain metastasis is resistant to therapy and a particularly poor prognostic feature in patient survival. Altered metabolism is a common feature of cancer cells, but little is known as to what metabolic changes benefit breast cancer brain metastases. We found that brain metastatic breast cancer cells evolved the ability to survive and proliferate independent of glucose due to enhanced gluconeogenesis and oxidations of glutamine and branched chain amino acids, which together sustain the nonoxidative pentose pathway for purine synthesis. Silencing expression of fructose-1,6-bisphosphatases (FBP) in brain metastatic cells reduced their viability and improved the survival of metastasis-bearing immunocompetent hosts. Clinically, we showed that brain metastases from human breast cancer patients expressed higher levels of FBP and glycogen than the corresponding primary tumors. Together, our findings identify a critical metabolic condition required to sustain brain metastasis and suggest that targeting gluconeogenesis may help eradicate this deadly feature in advanced breast cancer patients.

Antiangiogenic Therapy with Human Apolipoprotein(a) Kringle V and Paclitaxel in a Human Ovarian Cancer Mouse Model.

INTRODUCTION: The present study compared the effect of combination therapy using human apolipoprotein(a) kringle V (rhLK8) to conventional chemotherapy with paclitaxel for human ovarian carcinoma producing high or low levels of vascular endothelial growth factor (VEGF). MATERIALS AND METHODS: Human ovarian carcinoma cells producing high (SKOV3ip1) or low (HeyA8) levels of VEGF were implanted into the peritoneal cavity of female nude mice. Seven days later, mice were randomized into four groups: control (vehicle), paclitaxel [5 mg/kg, weekly intraperitoneal (i.p.) injection], rhLK8 (50 mg/kg, daily i.p. injection), or the combination of paclitaxel and rhLK8. Mice were treated for 4 weeks and examined by necropsy. RESULTS: In mice implanted with SKOV3ip1 cells, rhLK8 treatment had no significant effect on tumor incidence or the volume of ascites but induced a significant decrease in tumor weight compared with control mice. Paclitaxel significantly reduced tumor weight and ascites volume, and combination treatment with paclitaxel and rhLK8 had an additive therapeutic effect. Similarly, in HeyA8 mice, the effect of combination treatment on tumor weight and tumor incidence was statistically significantly greater than that of paclitaxel or rhLK8 alone. Immunohistochemical analysis showed a significant decrease in microvessel density and a marked increase of apoptosis in tumor and tumor-associated endothelial cells in response to combination treatment with paclitaxel and rhLK8. CONCLUSION: Collectively, these results suggest that antiangiogenic therapy with rhLK8 in combination with taxane-based conventional chemotherapy could be effective for the treatment of ovarian carcinomas, regardless of VEGF status.

Role of the endothelin axis in astrocyte- and endothelial cell-mediated chemoprotection of cancer cells.

BACKGROUND: Recent evidence suggests that astrocytes protect cancer cells from chemotherapy by stimulating upregulation of anti-apoptotic genes in those cells. We investigated the possibility that activation of the endothelin axis orchestrates survival gene expression and chemoprotection in MDA-MB-231 breast cancer cells and H226 lung cancer cells. METHODS: Cancer cells, murine astrocytes, and murine fibroblasts were grown in isolation, and expression of endothelin (ET) peptides and ET receptors (ETAR and ETBR) compared with expression on cancer cells and astrocytes (or cancer cells and fibroblasts) that were co-incubated for 48 hours. Type-specific endothelin receptor antagonists were used to evaluate the contribution of ETAR and ETBR to astrocyte-induced activation of the protein kinase B (AKT)/mitogen-activated protein kinase (MAPK) signal transduction pathways, anti-apoptotic gene expression, and chemoprotection of cancer cells. We also investigated the chemoprotective potential of brain endothelial cells and microglial cells. RESULTS: Gap junction signaling between MDA-MB-231 cancer cells and astrocytes stimulates upregulation of interleukin 6 (IL-6) and IL-8 expression in cancer cells, which increases ET-1 production from astrocytes and ET receptor expression on cancer cells. ET-1 signals for activation of AKT/MAPK and upregulation of survival proteins that protect cancer cells from taxol. Brain endothelial cell-mediated chemoprotection of cancer cells also involves endothelin signaling. Dual antagonism of ETAR and ETBR is required to abolish astrocyte- and endothelial cell-mediated chemoprotection. CONCLUSIONS: Bidirectional signaling between astrocytes and cancer cells involves upregulation and activation of the endothelin axis, which protects cancer cells from cytotoxicity induced by chemotherapeutic drugs.

Suppression of colorectal cancer liver metastasis by apolipoprotein(a) kringle V in a nude mouse model through the induction of apoptosis in tumor-associated endothelial cells.

The formation of liver metastases in colorectal cancer patients is the primary cause of patient death. Current therapies directed at liver metastasis from colorectal cancer have had minimal impact on patient outcomes. Therefore, the development of alternative treatment strategies for liver metastasis is needed. In the present study, we demonstrated that recombinant human apolipoprotein(a) kringle V, also known as rhLK8, induced the apoptotic turnover of endothelial cells in vitro through the mitochondrial apoptosis pathway. The interaction of rhLK8 with glucose-regulated protein 78 (GRP78) may be involved in the induction of apoptosis because the inhibition of GRP78 by GRP78-specific antibodies or siRNA knockdown inhibited the rhLK8-mediated apoptosis of human umbilical vein endothelial cells in vitro. Next, to evaluate the effects of rhLK8 on angiogenesis and metastasis, an experimental model of liver metastasis was established by injecting a human colorectal cancer cell line, LS174T, into the spleens of BALB/c nude mice. The systemic administration of rhLK8 significantly suppressed liver metastasis from human colorectal cancer cells and improved host survival compared with controls. The combination of rhLK8 and 5-fluorouracil substantially increased these survival benefits compared with either therapy alone. Histological observation showed significant induction of apoptosis among tumor-associated endothelial cells in liver metastases from rhLK8-treated mice compared with control mice. Collectively, these results suggest that the combination of rhLK8 with conventional chemotherapy may be a promising approach for the treatment of patients with life-threatening colorectal cancer liver metastases.

Flavonoids Identified from Korean Scutellaria baicalensis Georgi Inhibit Inflammatory Signaling by Suppressing Activation of NF- κ B and MAPK in RAW 264.7 Cells.

Scutellaria baicalensis Georgi has been used as traditional medicine for treating inflammatory diseases, hepatitis, tumors, and diarrhea in Asia. Hence, we investigated the anti-inflammatory effect and determined the molecular mechanism of action of flavonoids isolated from Korean S. baicalensis G. in lipopolysaccharide- (LPS-) stimulated RAW 264.7 macrophages. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to examine cytotoxicity of the flavonoids at various concentrations of 10, 40, 70, and 100 µg/mL. No cytotoxicity was observed in RAW 264.7 cells at these concentrations. Furthermore, the flavonoids decreased production of inflammatory mediators such as inducible nitric oxide synthase, cyclooxygenase-2, interleukin-6, and tumor necrosis factor-alpha and inhibited phosphorylation of nuclear factor-kappa B (NF- κ B) and mitogen-activated protein kinases (MAPKs) in LPS-induced RAW 264.7 cells. Moreover, to identify the differentially expressed proteins in RAW 264.7 cells of the control, LPS-treated, and flavonoid-treated groups, two-dimensional gel electrophoresis and mass spectrometry were conducted. The identified proteins were involved in the inflammatory response and included PRKA anchor protein and heat shock protein 70 kD. These findings suggest that the flavonoids isolated from S. baicalensis G. might have anti-inflammatory effects that regulate the expression of inflammatory mediators by inhibiting the NF- κ B signaling pathway via the MAPK signaling pathway in RAW 264.7 cells.

Characterization of CD45-/CD31+/CD105+ circulating cells in the peripheral blood of patients with gynecologic malignancies.

PURPOSE: Circulating endothelial cells (CEC) have been widely used as a prognostic biomarker and regarded as a promising strategy for monitoring the response to treatment in several cancers. However, the presence and biologic roles of CECs have remained controversial for decades because technical standards for the identification and quantification of CECs have not been established. Here, we hypothesized that CECs detected by flow cytometry might be monocytes rather than endothelial cells. EXPERIMENTAL DESIGN: The frequency of representative CEC subsets (i.e., CD45(-)/CD31(+), CD45(-)/CD31(+)/CD146(+), CD45(-)/CD31(+)/CD105(+)) was analyzed in the peripheral blood of patients with gynecologic cancer (n = 56) and healthy volunteers (n = 44). CD45(-)/CD31(+) cells, which are components of CECs, were isolated and the expression of various markers (CD146, CD105, vWF, and CD144 for endothelial cells; CD68 and CD14 for monocytes) was examined by immunocytochemistry. RESULTS: CD45(-)/CD31(+)/CD105(+) cells were significantly increased in the peripheral blood of patients with cancer, whereas evaluation of CD45(-)/CD31(+)/CD146(+) cells was not possible both in patients with cancer and healthy controls due to the limited resolution of the flow cytometry. Immunocytochemistry analyses showed that these CD45(-)/CD31(+)/CD105(+) cells did not express vWF and CD146 but rather CD144. Furthermore, CD45(-)/CD31(+)/CD105(+) cells uniformly expressed the monocyte-specific markers CD14 and CD68. These results suggest that CD45(-)/CD31(+)/CD105(+) cells carry the characteristics of monocytes rather than endothelial cells. CONCLUSIONS: Our data indicate that CD45(-)/CD31(+)/CD105(+) circulating cells, which are significantly increased in the peripheral blood of patients with gynecologic cancer, are monocytes rather than endothelial cells. Further investigation is required to determine the biologic significance of their presence and function in relation with angiogenesis.

Immunoglobulin Fc domain fusion to apolipoprotein(a) kringle V significantly prolongs plasma half-life without affecting its anti-angiogenic activity.

Angiogenesis is crucial for tumor growth and metastasis. Blocking this process is, therefore, a potentially powerful approach for the treatment of cancer. Human apolipoprotein(a) kringle V (rhLK8) is an angiogenesis inhibitor and is currently under development as an anti-cancer therapeutic. However, a relatively short in vivo half-life limits its widespread clinical use. This study was performed to evaluate whether fusion of an Fc domain to rhLK8 can extend plasma half-life. RhLK8-Fc fusion protein was expressed in CHO DG44 cells as a dimer and was readily purified by protein G affinity chromatography. The anti-angiogenic activity of rhLK8-Fc was similar to that of rhLK8, as determined by migration and tube formation assays with endothelial cells in vitro and a chorioallantoic membrane assay in vivo. Pharmacokinetic profiles in mice after single intravenous administration of rhLK8 or rhLK8-Fc showed that Fc fusion significantly increased the elimination half-life (t(½)) and the systemic exposure (AUC(inf)) of the protein, in parallel with a significant decrease in total clearance (CL). These data suggest that Fc fusion to rhLK8 is a powerful strategy for extending the plasma half-life of rhLK8 without affecting its anti-angiogenic activity, and could thus improve the clinical applicability of rhLK8.

Repeated intravenous infusion of human apolipoprotein(a) kringle V is associated with reversible dose-dependent acute tubulointerstitial nephritis without affecting glomerular filtration function.

Because anti-angiogenic agents have shown various toxicities in clinical applications, the determination of their toxicities and their reversibility is important in the design of clinical trials. This study was performed to investigate the potential toxicities of an angiogenesis inhibitor, apolipoprotein(a) (Apo(a)) kringle V (rhLK8) in rats. Rats administered an intravenous (IV) bolus injection of rhLK8 (200 mg/kg) for 7 days showed significant increases in serum blood urea nitrogen (BUN), creatinine and the BUN/creatinine ratio, which was compatible with acute tubulointerstitial nephritis (TIN) in pathological examination. Because anti-angiogenic therapies are usually based on long-term treatment strategies, rats were administered 200 mg/kg/day of rhLK8 by intravenous infusion for 28 days. Rats receiving 200 mg/kg of rhLK8 showed abnormal serological and histologic findings, but their levels returned to within normal ranges 2 weeks after the cessation of administration. The creatinine clearance rate (CCr) was not affected by rhLK8 treatment. Collectively, our data indicate that the intravenous infusion of rhLK8 at therapeutic doses may induce renal toxicities, such as acute TIN, but these toxicities are clinically tolerable and reversible with close monitoring and a recovery period.

Targeted antivascular therapy with the apolipoprotein(a) kringle V, rhLK8, inhibits the growth and metastasis of human prostate cancer in an orthotopic nude mouse model.

Antivascular therapy has emerged as a rational strategy to improve the treatment of androgen-independent prostate cancer owing to the necessity of establishing a vascular network for the growth and progression of the primary and metastatic tumor. We determined whether recombinant human apolipoprotein(a) kringle V, rhLK8, produces therapeutic efficacy in an orthotopic human prostate cancer animal model. Fifty thousand androgen-independent human prostate cancer cells (PC-3MM2) were injected into the prostate of nude mice. After 3 days, these mice were randomized to receive the vehicle solution (intraperitoneally [i.p.], daily), paclitaxel (8 mg/kg i.p., weekly), rhLK8 (50 mg/kg i.p., daily), or a combination of paclitaxel and rhLK8 for 4 weeks. Treatment with paclitaxel or rhLK8 alone did not show significant therapeutic effects on tumor incidence or on tumor size compared with the control group. The combination of rhLK8 and paclitaxel significantly reduced tumor size and incidence of lymph node metastasis. Significant reduction in microvessel density and cellular proliferation and induction of apoptosis of tumor cells, and tumor-associated endothelial cells, were also achieved. Similarly, PC-3MM2 tumors growing in the tibia showed significant suppression of tumor growth and lymph node metastasis by the combination treatment with rhLK8 and paclitaxel. The integrity of the bone was significantly preserved, and apoptosis of tumor cells and tumor-associated endothelial cells was increased. In conclusion, these results suggest that targeting the tumor microenvironment with the antivascular effect of rhLK8 combined with conventional cytotoxic chemotherapy could be a new and effective approach in the treatment of androgen-independent prostate cancer and their metastases.

Antiangiogenic kringles derived from human plasminogen and apolipoprotein(a) inhibit fibrinolysis through a mechanism that requires a functional lysine-binding site.

Many proteins in the fibrinolysis pathway contain antiangiogenic kringle domains. Owing to the high degree of homology between kringle domains, there has been a safety concern that antiangiogenic kringles could interact with common kringle proteins during fibrinolysis leading to adverse effects in vivo. To address this issue, we investigated the effects of several antiangiogenic kringle proteins including angiostatin, apolipoprotein(a) kringles IV(9)-IV(10)-V (LK68), apolipoprotein(a) kringle V (rhLK8) and a derivative of rhLK8 mutated to produce a functional lysine-binding site (Lys-rhLK8) on the entire fibrinolytic process in vitro and analyzed the role of lysine binding. Angiostatin, LK68 and Lys-rhLK8 increased clot lysis time in a dose-dependent manner, inhibited tissue-type plasminogen activator-mediated plasminogen activation on a thrombin-modified fibrinogen (TMF) surface, showed binding to TMF and significantly decreased the amount of plasminogen bound to TMF. The inhibition of fibrinolysis by these proteins appears to be dependent on their functional lysine-binding sites. However, rhLK8 had no effect on these processes owing to an inability to bind lysine. Collectively, these results indicate that antiangiogenic kringles without lysine binding sites might be safer with respect to physiological fibrinolysis than lysine-binding antiangiogenic kringles. However, the clinical significance of these findings will require further validation in vivo.

Inhibition of the proliferation and invasion of hepatocellular carcinoma cells by lipocalin 2 through blockade of JNK and PI3K/Akt signaling.

Lipocalin 2 (Lcn2) has been reported to induce cellular proliferation based on its expression in a variety of proliferative cells. Consistent with these findings, the present study demonstrates a significant increase in Lcn2 levels in human hepatocellular carcinoma (HCC) tissues compared with non-tumor liver tissues. However, the role of Lcn2 in hepatocarcinogenesis is far from clear. To investigate the effects of Lcn2 expression on hepatocarcinogenesis, Chang liver and SK-Hep1 HCC cell lines were genetically manipulated to express Lcn2, and the effects on the proliferation and invasion of HCC cells were analyzed. Ectopic expression of Lcn2 in HCC cells significantly inhibited the growth of HCC cells in vitro and in vivo, reduced the invasive potential of cells, and inhibited the expression of matrix metalloproteinase 2 (MMP-2). Lcn2 may exert its function partly through the inhibition of the c-Jun N-terminal kinase (JNK) and phospha-tidyl inositol 3'-kinase (PI3K)/Akt signaling pathways in HCC cells. The selective inhibition of these pathways using pharmacological inhibitors significantly inhibited proliferation, invasion and MMP-2 expression, whereas Lcn2 expression suppressed the JNK and PI3K/Akt pathways. Collectively, these results clearly indicate that Lcn2 may play a protective role against the progression of HCCs by suppressing cell proliferation and invasion. The clinical significance of the present findings should be evaluated further.

Antibacterial characteristics of Curcuma xanthorrhiza extract on Streptococcus mutans biofilm.

This study evaluated the antibacterial effects of a natural Curcuma xanthorrhiza extract (Xan) on a Streptococcus mutans biofilm by examining the bactericidal activity, inhibition of acidogenesis and morphological alteration. Xan was obtained from the roots of a medicinal plant in Indonesia, which has shown selective antibacterial effects on planktonic S. mutans. S. mutans biofilms were formed on slide glass over a 72 h period and treated with the following compounds for 5, 30, and 60 min: saline, 1% DMSO, 2 mg/ml chlorhexidine (CHX), and 0.1 mg/ml Xan. The Xan group exposed for 5 and 30 min showed significantly fewer colony forming units (CFU, 57.6 and 97.3%, respectively) than those exposed to 1% DMSO, the negative control group (P<0.05). These CFU were similar in number to those slides exposed to CHX, the positive control group. Xan showed similar bactericidal effect to that of CHX but the dose of Xan was one twentieth that of CHX. In addition, the biofilms treated with Xan and CHX maintained a neutral pH for 4 h, which indicates that Xan and CHX inhibit acid production. Scanning electron microscopy showed morphological changes in the cell wall and membrane of the Xan-treated biofilms; an uneven surface and a deformation in contour. Overall, natural Xan has strong bactericidal activity, inhibitory effects on acidogenesis, and alters the microstructure of S. mutans biofilm. In conclusion, Xan has potential in anti-S. mutans therapy for the prevention of dental caries.

Progressive neuronal loss and behavioral impairments of transgenic C57BL/6 inbred mice expressing the carboxy terminus of amyloid precursor protein.

The beta-secretase cleaved Abeta-bearing carboxy-terminal fragments (betaCTFs) of amyloid precursor protein (APP) in neural cells have been suggested to be cytotoxic. However, the functional significance of betaCTFs in vivo remains elusive. We created a transgenic mouse line Tg-betaCTF99/B6 expressing the human betaCTF99 in the brain of inbred C57BL/6 strain. Tg-betaCTF99/B6 mouse brain at 12-16 months showed severely down-regulated calbindin, phospho-CREB, and Bcl-xL expression and up-regulated phospho-JNK, Bcl-2, and Bax expression. Neuronal cell density in the Tg-betaCTF99/B6 cerebral cortex at 16-18 months was lower than that of the non-transgenic control, but not at 5 months. At 11-14 months, Tg-betaCTF99/B6 mice displayed cognitive impairments and increased anxiety, which were not observed at 5 months. These results suggest that increased betaCTF99 expression is highly detrimental to the aging brain and that it produces a progressive and age-dependent AD-like pathogenesis.

Ectopic expression of neutrophil gelatinase-associated lipocalin suppresses the invasion and liver metastasis of colon cancer cells.

Neutrophil gelatinase-associated lipocalin (NGAL), also known as lipocalin 2, is a 25-kDa lipocalin initially purified from neutrophil granules. It is thought to play a role in regulating cellular growth since its expression is highly upregulated in a variety of proliferative cells such as cancer cells. However, experimental evidence showing a clear causal relationship between NGAL expression and the proliferation of tumor cells is lacking. Here, we found NGAL expression in highly and poorly metastatic colon cancer cell lines of the same genetic origin correlated inversely with the metastatic potential of these cells, which suggests NGAL participates in the metastatic process. To explore the role NGAL plays in tumor growth and metastasis, the KM12SM human colon cancer cell line, which is highly metastatic while showing decreased NGAL expression, was genetically manipulated to overexpress NGAL. The effects of this on tumor growth and liver metastasis were then analyzed using experimental animal models established by injecting BALB/c nude mice with tumor cells subcutaneously or intrasplenically. Ectopic expression of NGAL in the colon cancer cells had little effect on the growth and viability of the tumor cells both in vitro and in vivo. However, NGAL expression not only suppressed the ability of the colon carcinoma cells to invade Matrigel in vitro, it also substantially inhibited liver metastasis in an experimental animal model. Collectively, these results indicate that NGAL may be a candidate metastasis suppressor in colon cancer cells.

Effect of iontophoretical application of NK1 receptor antagonists on pulpal blood flow in cats.

The influence of NK1 receptor antagonists applied iontophoretically on pulpal blood flow (PBF) was investigated. Along with substance P (SP, 0.8 approximately 20.0 ng/kg) administration to the canine pulp through the catheterized lingual artery, two NK1 receptor antagonists, [D-Pro2,D-Trp7,9]-SP and [D-Pro2,D-Phe7,D-Trp9]-SP (0.2 approximately 3.4 mM) were applied iontophoretically (cathodal current, 0.02 approximately 0.1 mA, 1 min) to the prepared class V dentinal cavity of ipsilateral teeth in 11 generally anesthetized cats. A paired t-test showed that SP administration caused significant increases of PBF (p < 0.05) without changing systemic blood pressure, and that SP and SP antagonist administration caused significantly less increase of PBF than in control of SP and 0.9% saline administration (p < 0.05). These data provide evidence that the iontophoretic application of NK1 receptor antagonists effectively attenuates SP-induced vasodilatation and show the possibility of their use in the control of neurogenic inflammation in the dental pulp.

Expression of human apolipoprotein(a) kringles in colon cancer cells suppresses angiogenesis-dependent tumor growth and peritoneal dissemination.

BACKGROUND: Anti-angiogenesis therapy has been regarded as a promising treatment of cancer based on the fact that most tumors and their metastasis are angiogenesis-dependent. Gene therapy can potentially expand the horizons of tumor angiogenesis therapy by virtue of its ability to produce high concentrations of therapeutic agents in a local area for a sustained period. The present study was performed to evaluate the therapeutic potential of gene therapy for the treatment of cancer and metastasis. METHODS: The murine colon carcinoma cell line CT26 was manipulated ex vivo to express an anti-angiogenic molecule, LK68, consisting of human apolipoprotein(a) kringle domains, KIV(9)-KIV(10)-KV, using retrovirus-mediated gene transfer. Its effects on colon tumor growth and metastasis were evaluated in experimental animal models established by injecting LK68-expressing and control CT26 cells subcutaneously or into the peritoneal cavity of BALB/c mice, respectively. RESULTS: Expression of LK68 significantly suppressed colon tumor growth in mice, but did not influence the growth of tumor cells in vitro. Immunohistochemical analysis of tumor tissues revealed a significant reduction in microvessel density in LK68-expressing tumors. Thus, the suppression of tumor growth appears to result mainly from inhibition of tumor angiogenesis. This decrease in vessel density is correlated with a notable increase in tumor cell apoptosis in vivo, but has no influence on proliferation. Moreover, expression of LK68 prevents peritoneal dissemination, and consequently improves overall host survival. CONCLUSIONS: These results collectively indicate that a gene therapy strategy using LK68 cDNA is useful for the treatment for both colon tumor growth and peritoneal dissemination.

Suppression of colorectal cancer liver metastasis and extension of survival by expression of apolipoprotein(a) kringles.

The formation of hepatic metastases in colorectal cancer is the main cause of patient death. Current therapies directed at hepatic metastasis of colorectal cancer have had minimal impact on outcome. Therefore, alternative treatment strategies for liver metastasis require development. The present study was performed to evaluate the application of cDNA of LK68 encoding apolipoprotein(a) kringles IV-9, IV-10, and V as possible candidates for gene therapy treatment of this life-threatening disease. The murine colorectal cancer cell line CT26 was transduced ex vivo with LK68 cDNA via retroviral gene transfer, and an experimental model of hepatic metastasis was established by injecting LK68-expressing and control cells into the spleens of BALB/c mice. Expression of LK68 did not affect the growth characteristics and viability of transduced CT26 cells in vitro. LK68 produced from CT26 cells substantially inhibited the migration of endothelial cells in vitro. In vivo, substantial suppression of liver metastasis and prolonged survival were observed in mice bearing LK68-expressing CT26 cells, compared with controls. LK68-expressing liver metastases were restricted to smaller sizes and displayed decreased microvessel density and increased tumor cell apoptosis. Our data collectively indicate that LK68 suppresses angiogenesis-dependent progression of prevascular micrometastases to macroscopic tumors and their growth, which are clinically accessible and biologically relevant therapeutic targets. We propose that antiangiogenic gene therapy with LK68 is a promising strategy for the treatment of colorectal cancer liver metastasis.