Isomeric methoxy analogs of nimesulide for development of brain cyclooxygense-2 (COX-2)-targeted imaging agents: Synthesis, in vitro COX-2-inhibitory potency, and cellular transport properties.

Nimesulide analogs bearing a methoxy substituent either at the ortho-, meta- or para-position on the phenyl ring, were designed, synthesized, and evaluated for potential as radioligands for brain cyclooxygenase-2 (COX-2) imaging. The synthesis of nimesulide and regioisomeric methoxy analogs was based on the copper-mediated arylation of phenolic derivatives for the construction of diaryl ethers. These isomeric methoxy analogs displayed lipophilicity similar to that of nimesulide itself, as evidenced by their HPLC logP7.

Farnesoid X receptor knockdown provides significant growth inhibition in hepatocellular carcinoma cells while it does not interfere with the proliferation of primary human hepatocyte-derived cells.

Identification of substances with specific toxicity for carcinoma cells promises to facilitate the development of cancer chemotherapeutics that cause minimal side effects. Here, we show that knockdown of the farnesoid X receptor (FXR) effectively suppresses the proliferation of human hepatocellular carcinoma cell lines HepG2 and HLE accompanied by elevated expression of cyclin-dependent kinase (CDK) inhibitor p16/INK4a and p21/Cip1 proteins. On the other hand, the growth of the primary human hepatocyte-derived cell line Fa2N-4 is not affected by the treatment with FXR siRNA irrespective of marked increases in the mRNAs of p16/INK4a and p21/Cip1.

Loss of EGF-dependent cell proliferation ability on radioresistant cell HepG2-8960-R.

Acquired radioresistance of cancer cells interferes with radiotherapy and increases the probability of cancer recurrence. HepG2-8960-R, which is one of several clinically relevant radioresistant (CRR) cell lines, has a high tolerance to the repeated clinically relevant doses of X-ray radiation. In this study, HepG2-8960-R had slightly lower cell proliferation ability than HepG2 in the presence of FBS.

Loss of α1,6-fucosyltransferase suppressed liver regeneration: implication of core fucose in the regulation of growth factor receptor-mediated cellular signaling.

Core fucosylation is an important post-translational modification, which is catalyzed by α1,6-fucosyltransferase (Fut8). Increased expression of Fut8 has been shown in diverse carcinomas including hepatocarcinoma. In this study, we investigated the role of Fut8 expression in liver regeneration by using the 70% partial hepatectomy (PH) model, and found that Fut8 is also critical for the regeneration of liver.

Guanine nucleotide-binding protein 1 is one of the key molecules contributing to cancer cell radioresistance.

Standard fractionated radiotherapy for the treatment of cancer consists of daily irradiation of 2-Gy X-rays, 5 days a week for 5-8 weeks. To understand the characteristics of radioresistant cancer cells and to develop more effective radiotherapy, we established a series of novel, clinically relevant radioresistant (CRR) cells that continue to proliferate with 2-Gy X-ray exposure every 24 h for more than 30 days in vitro. We studied three human and one murine cell line, and their CRR derivatives.

Targeting of tumor endothelial cells combining 2 Gy/day of X-ray with Everolimus is the effective modality for overcoming clinically relevant radioresistant tumors.

Radiotherapy is widely used to treat cancer because it has the advantage of physically and functionally conserving the affected organ. To improve radiotherapy and investigate the molecular mechanisms of cellular radioresistance, we established a clinically relevant radioresistant (CRR) cell line, SAS-R, from SAS cells. SAS-R cells continue to proliferate when exposed to fractionated radiation (FR) of 2 Gy/day for more than 30 days in vitro.

Radiosynthesis and initial evaluation of (18)F labeled nanocarrier composed of poly(L-lactic acid)-block-poly(sarcosine) amphiphilic polydepsipeptide.

Introduction: With the aim of developing radiotracers for in vivo positron emission tomography (PET) imaging of solid tumors based on the enhanced permeability and retention effect of nanocarriers, we have developed a polymer micelle named "Lactosome", which is composed of the amphiphilic polydepsipeptide, poly(L-lactic acid)-block-poly(sarcosine). This paper describes and evaluates the initial evaluation of the (18)F-labeled Lactosome as a novel contrast agent for the tumor PET imaging technique carried out.

Methods: (18)F-labeled Lactosomes were prepared by a film hydration method under sonication in water at 50°C from a mixture of 4-[(18)F]fluoro-benzoyl poly-L-lactic acid ((18)F-BzPLLA30) and the amphiphilic polydepsipeptide.

Critical role of farnesoid X receptor for hepatocellular carcinoma cell proliferation.

Farnesoid X receptor (FXR), a pivotal factor maintaining bile acid homeostasis, has been recently shown to be a critical factor required for liver regeneration. The elucidation of the mechanism how FXR controls the proliferation of hepatocellular carcinoma cells is useful to establish the therapy for liver cancer. Here, we show that FXR plays a crucial role in the proliferation of human hepatocellular carcinoma cell line, HepG2, Huh7 and HLE.

Norepinephrine modulates the zonally different hepatocyte proliferation through the regulation of transglutaminase activity.

A neurotransmitter, norepinephrine (NE), amplifies the mitogenic effect of epidermal growth factor (EGF) in the liver by acting on the alpha(1)-adrenergic receptor coupled with G protein, Galpha(h). However, the molecular mechanism is not well understood. Galpha(h) is known as a transglutaminase 2 (TG2), a cross-linking enzyme implicated in hepatocyte proliferation.

The modified high-density survival assay is the useful tool to predict the effectiveness of fractionated radiation exposure.

The high-density survival (HDS) assay was originally elaborated to assess cancer cell responses to therapeutic agents under the influence of intercellular communication. Here, we simplified the original HDS assay and studied its applicability for the detection of cellular radioresistance. We have recently defined clinically relevant radioresistant (CRR) cells, which continue to proliferate with daily exposure to 2 gray (Gy) of X-rays for more than 30 days in vitro.

Clinically relevant radioresistant cells efficiently repair DNA double-strand breaks induced by X-rays.

Radiotherapy is one of the major therapeutic modalities for eradicating malignant tumors. However, the existence of radioresistant cells remains one of the most critical obstacles in radiotherapy and radiochemotherapy. Standard radiotherapy for tumor treatment consists of approximately 2 Gy once a day, 5 days a week, over a period of 5-8 weeks.

Stabilities of 67ga- and 111In-labeled transferrin in vitro.

We attempted to develop a stable radiolabeled transferrin (Tf) useful in experimental studies related to Tf receptor. 67Ga and 111In were used as labeling radioisotopes. The results from gel chromatography, dialysis, and electrophoresis showed that 111In-DTPA-Tf was the most stable among the radiolabeled Tfs examined in the present study.

The uptake of 111In in the liver and bone marrow of partially hepatectomized and venesectioned rats.

Indium-111 ((111)In) has a strong binding affinity for transferrin (Tf), and the (111)In-Tf complex binds to Tf receptor in various tissues. In partial hepatectomy (PH), a part of blood in circulation is lost along with removed liver tissues; consequently, the number of blood cells and the amount of Tf in circulation decreases. These decreases should greatly affect the uptake of (111)In in the liver and bone marrow.

Gene expression profiles in mouse liver cells after exposure to different types of radiation.

The liver is one of the target organs of radiation-induced cancers by internal exposures. In order to elucidate radiation-induced liver cancers including Thorotrast, we present a new approach to investigate in vivo effects of internal exposure to alpha-particles. Adopting boron neutron capture, we separately irradiated Kupffer cells and endothelial cells in mouse liver in vivo and analyzed the changes in gene transcriptions by an oligonucleotide microarray.

Effect of retinoic acid on transglutaminase and ornithine decarboxylase activities during liver regeneration.

Liver regeneration is regulated by several factors, including growth factors, cytokines, and post-translational modifications of several proteins. It is suggested that transglutaminase 2 (TG2) and ornithine decarboxylase (ODC) are involved in liver regeneration. To investigate the role of TG2 and ODC activities in regenerating liver, we used retinoic acid (RA), an inducer of TG2 and a suppressor of ODC.

Transglutaminase catalyzed dissociation and association of protein-polyamine complex.

Transglutaminase 2 (TG2) has been reported to be involved in cell growth through the formation of epsilon-(gamma-glutamyl) lysine (Gln-Lys) or N-(gamma-glutamyl) polyamine (Gln-polyamine). We have recently reported that the inhibition of Gln-Lys cross-linking by the formation of Gln-spermidine led to the increase of DNA synthesis in regenerating rat liver. TG2 may catalyze the replacement reaction between Lys residues in protein and polyamines.

Analysis of Common Deletion (CD) and a novel deletion of mitochondrial DNA induced by ionizing radiation.

Purpose: In order to identify supportive evidence of radiation exposure to cells, we analyzed the relationship between exposure to ionizing radiation and the induction of deletions in mitochondrial DNA (mtDNA).

Materials And Methods: Using human hepatoblastoma cell line, HepG2 and its derivatives, HepG2-A, -89 and -400, established after long term exposure to X-ray, mtDNA deletions were analyzed by polymerase chain reaction (PCR) and real-time PCR after cells were subjected to radiation and genotoxic treatments.

Results: Common Deletion (CD), the most extensively studied deletion of mtDNA, was induced within 24 h after exposure to 5 Gray (Gy) of X-rays and was associated with replication of mtDNA.

The uptake mechanism of gallium-67 into hepatocytes treated with carbon tetrachloride.

We have recently reported that transferrin (Tf)-unbound gallium-67 (67Ga) may be taken up into the liver of carbon tetrachloride (CCl4)-treated rats. In the present study, we attempted to clarify detailed mechanism of Tf-unbound 67Ga uptake by hepatocytes treated with CCl4 using in vitro experimental system. Hepatotoxic damages by CCl4 are mostly attributed to radical formed by an action of cytochrome P450.

Oxidative stress induced lipocalin 2 gene expression: addressing its expression under the harmful conditions.

Lipocalin 2 (Lcn2, NGAL) is a member of the lipocalin superfamily with diverse functions such as the transport of fatty acids and the induction of apoptosis. Previous reports indicated that expression of Lcn2 is induced under harmful conditions. However, the mechanisms of the induction of Lcn2 expression remain to be elucidated.

Involvement of retinoic acid-induced transglutaminase activity in zonal differences of hepatocyte proliferation after partial hepatectomy.

Background: The authors have recently demonstrated that there is inverse correlation between transglutaminase (TGase) activity and DNA synthesis in periportal hepatocytes (PPH) and perivenous hepatocytes (PVH) at 1 day after partial hepatectomy in rats. In order to ensure the involvement of TGase in the differential growth capacities between periportal and perivenous regions of regenerating liver, the aim of this study was to investigate the effect of retinoic acid, an inducer of TGase expression, on zonal differences of hepatocyte proliferation between PPH and PVH isolated from regenerating rat liver.

Methods: Regenerating liver was prepared by 70% partial hepatectomy.

Zonal differences in gallium-67 uptakes between perivenous versus periportal regions of rat liver following carbon tetrachloride treatment.

Gallium-67 ((67)Ga) has been used as a tumor or inflammation-imaging agent in nuclear medicine, although underlying mechanism has not been fully elucidated. To gain some insights into the mechanism of (67)Ga uptake by injured liver, we analyzed the difference between perivenous and periportal regions of rat liver in terms of (67)Ga uptake by hepatocytes at the site of inflammation caused by carbon tetrachloride (CCl(4))-treatment. Distribution of (67)Ga in rat liver sections was monitored with a BAS5000 system following hepatic injury by CCl(4)-treatment.