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Metal nanoparticles (NPs), such as gold NPs (AuNPs), are particularly sensitive to X-rays, and thus specific accumulation of AuNPs in a tumor would allow radiotherapy with low energy X-rays and reduced side effects. AuNPs can be generated using HAuCl4 and the natural polyphenol epigallocatechin-3-gallate (EGCG) in the presence of citrate. Here, we generated EGCG-AuNPs in the presence of several additives and examined the accumulation of these NPs in mouse tumors following intravenous administration. EGCG-AuNPs 15 ​nm in diameter in the presence of sodium alginate accumulated more in tumors compared to 40-nm-diameter EGCG-AuNPs. Furthermore, the results of in vitro cellular uptake and serum protein absorption studies suggest that adsorption of 15–16 ​kDa serum proteins to EGCG-AuNPs suppresses accumulation in tumors. Thus, tendency to adsorb specific proteins on EGCG-AuNPs surface should be tailored for enhancing their accumulation in tumors.

A 56-year-old female patient with left breast cancer presented at our hospital. Preoperative CT scan showed an isolated bilateral pectoralis major muscle defect and abnormal muscle originating from the entire sternum and inserting in the lower ribs and rectus sheath. Total mastectomy and axillary lymph node dissection were performed. We believe that this case is unique and that others like it have never been reported. If there is a defect in the pectoralis major muscle, reconstructive surgery with a tissue expander is contraindicated. Therefore, preoperative evaluation of the chest wall musculature on imaging is recommended.

Methionine addiction, a fundamental and general hallmark of cancer, known as the Hoffman Effect, is due to altered use of methionine for increased and aberrant transmethylation reactions. However, the linkage of methionine addiction and malignancy of cancer cells is incompletely understood. An isogenic pair of methionine-addicted parental osteosarcoma cells and their rare methionine-independent revertant cells enabled us to compare them for malignancy, their epithelial-mesenchymal phenotype, and pattern of histone-H3 lysine-methylation. Methionine-independent revertant 143B osteosarcoma cells (143B-R) were selected from methionine-addicted parental cells (143B-P) by their chronic growth in low-methionine culture medium for 4 passages, which was depleted of methionine by recombinant methioninase (rMETase). Cell-migration capacity was compared with a wound-healing assay and invasion capability was compared with a transwell assay in 143B-P and 143B-R cells in vitro. Tumor growth and metastatic potential were compared after orthotopic cell-injection into the tibia bone of nude mice in vivo. Epithelial-mesenchymal phenotypic expression and the status of H3 lysine-methylation were determined with western immunoblotting. 143B-P cells had an IC50 of 0.20 U/ml and 143B-R cells had an IC50 of 0.68 U/ml for treatment with rMETase, demonstrating that 143B-R cells had regained the ability to grow in low methionine conditions. 143B-R cells had reduced cell migration and invasion capability in vitro, formed much smaller tumors than 143B-P cells and lost metastatic potential in vivo, indicating loss of malignancy in 143B-R cells. 143B-R cells showed gain of the epithelial marker, ZO-1 and loss of mesenchymal markers, vimentin, Snail, and Slug and, an increase of histone H3K9me3 and H3K27me3 methylation and a decrease of H3K4me3, H3K36me3, and H3K79me3 methylation, along with their loss of malignancy. These results suggest that shifting the balance in histone methylases might be a way to decrease the malignant potential of cells. The present results demonstrate the rationale to target methionine addiction for improved sarcoma therapy.

Summary: Methionine addiction, found in all types of cancer investigated, is because of the overuse of methionine by cancer cells for excess transmethylation reactions. In the present study, we compared the histone H3 lysine-methylation status and degree of malignancy between methionine-addicted cancer cells and their isogenic methionine-independent revertants, selected by their growth in low concentration of methionine. The methionine-independent revertans can grow on low levels of methionine or independently of exogenous methionine using methionine precursors, as do normal cells. In the methionine-independent revertants, the excess levels of trimethylated histone H3 lysine marks found in the methionine-addicted parental cancer cells were reduced or lost, and their tumorigenicity and experimental metastatic potential in nude mice were also highly reduced. Methionine addiction of cancer is linked with malignancy and hypermethylation of histone H3 lysines. The results of the present study thus provide a unique framework to further understand a fundamental basis of malignancy.

Purpose: Effective methods to ameliorate radiation enteropathy have not been developed. To address this issue, we investigated the reduced form of coenzyme Q10 (rCoQ10) as a potential radioprotector in a mouse model. Methods and Materials: rCoQ10 was added to a standard laboratory mouse diet at a final concentration of 1.0% 9 days before irradiation and 30 days thereafter or dissolved in corn oil and administered transorally. Accumulated amounts of coenzyme Q10 (CoQ10) or coenzyme Q9 in the intestine were measured by high-performance liquid chromatography. Reactive oxygen species (ROS), apoptosis, and morphologic changes in the intestine were assessed by immunohistochemistry after administration of 13 Gy of x-ray to the mouse abdomen. Body weight and survival were monitored for 30 days after irradiation. Cytotoxicity using 3 human cancer cell lines and the tumor growth–inhibiting effect in a xenograft were investigated to determine whether rCoQ10 interferes with radiation-specific cytotoxic effects on tumor growth. Results: CoQ10 was greatly accumulated in all sections of the intestine after both massive transoral dosing and dietary administration, whereas coenzyme Q9 was not. Administration of rCoQ10 suppressed ROS production and inhibited apoptosis in the crypts, resulting in preservation of villi structures after irradiation. Notably, 92% of mice fed the rCoQ10-supplemented diet were healthy and alive 30 days after irradiation, whereas 50% of control mice died (P

Accumulating lines of evidence indicate that the N-terminal domain of prion protein (PrP) is involved in prion susceptibility in mice. In this study, to investigate the role of the octapeptide repeat (OR) region alone in the N-terminal domain for the susceptibility and pathogenesis of prion disease, we intracerebrally inoculated RML scrapie prions into tg(PrPΔOR)/Prnp(0/0) mice, which express mouse PrP missing only the OR region on the PrP-null background. Incubation times of these mice were not extended. Protease-resistant PrPΔOR, or PrP(Sc)ΔOR, was easily detectable but lower in the brains of these mice, compared to that in control wild-type mice. Consistently, prion titers were slightly lower and astrogliosis was milder in their brains. However, in their spinal cords, PrP(Sc)ΔOR and prion titers were abundant and astrogliosis was as strong as in control wild-type mice. These results indicate that the role of the OR region in prion susceptibility and pathogenesis of the disease is limited. We also found that the PrP(Sc)ΔOR, including the pre-OR residues 23-50, was unusually protease-resistant, indicating that deletion of the OR region could cause structural changes to the pre-OR region upon prion infection, leading to formation of a protease-resistant structure for the pre-OR region.

Background/Aim: BRCA1/2 mutations in breast cancer cells impair homologous recombination and promote alternative end joining (Alt-EJ) for DNA-damage repair. DNA polymerase theta, encoded by POLQ, plays a crucial role in Alt-EJ, making it a potential therapeutic target, particularly in BRCA1/2-mutant cancers. Methionine restriction is a promising approach to target cancer cells due to their addiction to this amino acid. The present study investigated the expression of POLQ in BRCA1/2 wild-type and BRCA1-mutant breast cancer cells under methionine restriction. Materials and Methods: POLQ mRNA expression was measured using qRT-PCR in BRCA1/2 wild-type (MDAMB-231) and BRCA1- mutant (HCC1937 and MDA-MB- 436) breast-cancer cells under normal, or serum-restricted, or serum- and methionine-restricted conditions. Results: Compared to BRCA1/2 wild-type cells, BRCA1-mutant cells displayed significantly higher basal POLQ expression in normal medium. Methionine restriction further increased POLQ expression in the BRCA1-mutant cells but decreased it in the BRCA1/2 wild-type cells. Conclusion: The present findings suggest that methionine restriction showed differential effects on POLQ expression, potentially impacting Alt-EJ activity, in BRCA1/2 wild-type and BRCA1- mutant breast-cancer cells. Further investigation is needed to explore the potential of combining methionine restriction with DNA-repair inhibitors, such as PARP inhibitors, to overcome drug resistance in BRCA1/2 mutant cancers. [ABSTRACT FROM AUTHOR]

Background/Aim: Methionine addiction is the elevated requirement for exogenous methionine for growth and survival of cancer cells, termed the Hoffman effect. Methionine-addicted cancer cells synthesize normal or excess amounts of methionine but still need an external source of methionine. Methionine restriction (MR) by either a methionine-free medium or in vivo by a low-methionine diet or by methioninase, selectively arrests cancer cells in the late S/G2 cell cycle phase, but not normal cells. The present study focuses on the comparison of production and secretion of exosomes by cancer cells under MR and normal conditions. Materials and Methods: MDA-MB-231 cells (triple-negative breast cancer), containing exosomes labeled with CD63-GFP (CD63-GFP exosomes), were visualized by fluorescence microscopy. MDA-MB-231 cells expressing exosome-specific CD63-GFP were cultured in methionine-containing (MET+) or in methionine-free (MET−) DMEM conditions. Exosomes were isolated from conditioned medium of cultured MDA-MD-231 cells by ultracentrifugation and characterized by nanoparticle tracking analysis (NTA) and Western blotting. Results: When MDA-MB-231-CD63-GFP cells were cultured under MR conditions, they arrested their growth and CD63-GFP-expressing exosomes were strongly increased in the cells. MR resulted in approximately a 2-fold increase in exosome production and secretion per cell, even though cell growth was arrested. Methionine restriction thus resulted in elevated exosome production and secretion per surviving cell. Conclusion: Exosome production and secretion in the cancer cells increased under MR, suggesting a relation between MR and exosome production and secretion. [ABSTRACT FROM AUTHOR]

Background/Aim: Methionine addiction is a fundamental and general hallmark of cancer, termed the Hoffman effect. Methionine addiction is due to excessive use of and dependence on methionine by cancer cells. In the present report, we correlated the extent of methionine addiction and degree of malignancy with the amount and stability of methylated histone H3 lysine marks. Materials and Methods: We established low- and high-malignancy variants from a parental human pancreatic-cancer cell line and compared their sensitivity to methionine restriction and histone H3 lysine methylation status. Results: A low-malignancy, low-methionine-addiction revertant of the parental pancreatic-cancer cell line had less methylated H3K9me3 and was less sensitive to methionine restriction effected by recombinant methioninase (rMETase) than the parental cell line. A high-malignancy variant of the pancreatic cancer cell line had increased methylated H3K9me3 and was more sensitive to methionine restriction by rMETase with regard to inhibition of proliferation and to instability of histone H3 lysine methylation than the parental cell line. Orthotopic malignancy in nude mice was reduced in the low-methionine-addiction revertant and greater in the high-malignancy variant than in the parental cell line. Conclusion: The present study indicates that the degree of malignancy is linked to the extent of methionine addiction and the level and instability of trimethylation of histone H3, suggesting these phenomena are linked as a fundamental basis of oncogenic transformation. [ABSTRACT FROM AUTHOR]

Background/Aim: Sarcomas are considered a heterogeneous disease with incomplete understanding of its molecular basis. In the present study, to further understand general molecular changes in sarcoma, patient-derived xenograft (PDX) mouse models of the three most common soft-tissue sarcomas: myxofibrosarcoma, undifferentiated pleomorphic sarcoma (UPS) and liposarcoma were established and the methylation status of histone H3 lysine marks was studied. Materials and Methods: Immunoblotting and immunohistochemical staining were used to quantify the extent of methylation of histone H3K4me3 and histone H3K9me3. Results: In all 3 sarcoma types in PDX models, histone H3K4me3 and H3K9me3 were found highly overmethylated compared to normal muscle tissue. Conclusion: Histone H3 lysine over-methylation may be a general basis of malignancy of the major sarcoma types. [ABSTRACT FROM AUTHOR]

Background/Aim: The discovery of the nude mouse model enabled the experimental growth of humanpatient tumors. However, the low establishment rate of tumors in nude and other immunodeficient strains of mice has limited wide-spread clinical use. Materials and Methods: In order to increase the establishment rate of surgical specimens of patient tumors, we transplanted tumors to nude mice subcutaneously along with large amounts of surrounding tissue of the tumor. Results: The new transplantation method increased the establishment rate in nude mice to 66% compared to the old method of implanting the surgical tumor specimen with surrounding tissue removed (14%). High stage and presence of metastasis in the patient donor are positively correlated to tumor engraftment in nude mice. Conclusion: The new method can potentially allow most cancer patients who undergo surgery or biopsy to have their own mouse model for drug-sensitivity testing. [ABSTRACT FROM AUTHOR]

Background/Aim: Surgical orthotopic implantation (SOI) is used to establish patient-derived orthotopic xenograft (PDOX) and other orthotopic mouse models. Orthotopic liver models can be challenging, as the liver parenchyma is prone to bleeding. The present report describes a sutureless method to implant tumors in the liver that reduces bleeding and procedural time. Materials and Methods: Human HCC cell-line (Huh-7-GFP) and CM2, a patient-derived coloncancer liver metastasis, were used for sutureless SOI of tumor fragments in the liver of nude mice. A small cavity was formed on the liver surface. A solitary tumor fragment was implanted in the cavity without suturing to create hemostasis. Results: Six weeks after sutureless SOI, the tumor volume of Huh-7-GFP (n=5) was 584.41±147.64 mm3 and the tumor volume of CM2 (n=5) was 1336.54±1038.20 mm3. The engraftment rate was 100%. Conclusion: This novel method for establishing orthotopic liver-implantation mouse models is suitable for studies of liver cancer and liver metastases due to its simple procedure and potential high engraftment rate. [ABSTRACT FROM AUTHOR]

Background/Aim: We have recently shown that oral recombinant methionase (o-rMETase) prevents obesity in mice on a high-fat (HF) diet. The present study aimed to determine if o-rMETase can inhibit the onset of diabetes in mice on a HF diet. Materials and Methods: The mice on a HF diet were divided into two groups: 1) HF+phosphate buffered saline (PBS) group; 2) HF+o-rMETase group. Results: The blood glucose level in the HF+PBS group increased to average of 201 mg/dl during the experimental period of 8 weeks. In contrast, the blood glucose level in the HF+o-rMETase group maintained an average of 126 mg/dl (p<0.01, HF+PBS vs. HF+o-rMETase). The glucose tolerance test showed a significant increase in tolerance in the HF+o-rMETase group at 120 min after glucose injection compared to the HF+PBS group (p=0.04). Visceral adipose tissue was significantly less in the HF+o-rMETase group than the HF+PBS group (p=0.05). There was no difference in insulin levels, cholesterol or triglycerides between the HF+PBS and HF+o-rMETase groups. Conclusion: o-rMETase inhibited the onset of diabetes as well as prevented obesity on a high-fat diet, offering a possibility of a new and easy-to-use alternative to severe dieting or insulin injections. [ABSTRACT FROM AUTHOR]

Background/Aim: We have recently shown that oral recombinant methionase (o-rMETase) prevents obesity and diabetes onset in mice on a high-fat (HF) diet. The present study aimed to determine if o-rMETase can inhibit the onset of nonalcoholic fatty liver disease (NAFLD) onset in mice on a high-fat diet. Materials and Methods: Male C57BL/6J mice in the control group were fed a normal-fat diet (NFD) (+6.5% fat), and other mice were fed a high-fat (HF) diet (+34.3% fat). Then, the mice on the HF diet were divided into two dietary groups: i) HF+phosphate buffered saline (PBS) group, and ii) HF+o-rMETase group. Result: The fatty change score in the livers of mice treated with HF+PBS increased to an average of 2.6 during the experimental period of 8 weeks. In contrast, the fatty change in the livers of mice on the HF+o-rMETase group had an average score of 0.92 (p=0.04, HF+PBS vs HF+o-rMETase). Conclusion: o-rMETase inhibited the onset of NAFLD as well as prevented obesity and the onset of diabetes on a high-fat diet, offering a possibility of a new paradigm to prevent liver cirrhosis or liver cancer via NAFLD. [ABSTRACT FROM AUTHOR]

Background/Aim: obesity is a world-wide recalcitrant problem leading to many diseases. Dietary methionine restriction (MR) has been shown to prevent obesity, but it is an onerous regimen. The present study aimed to determine the effects of oral recombinant methionase (o-rMETase), on preventing obesity in mice on a high-fat diet. Materials and Methods: Male C57BL/6J mice in the control group were fed a control diet (CD) (+6.5% fat) for 25 days, and others were fed a high-fat (HF) diet (+34.3% fat) for 25 days. Then, the mice were divided into three dietary groups: 1) HF + phosphate buffered saline (PBS) group; 2) HF + o-rMETase group; and 3) untreated non-HF group. Results: The mice on the CD increased in body weight by 14% during experimental period of 25 days; in contrast the mice in the HF+PBS group increased by 33%; however, the mice on the HF+o-rMETase group increased only by 14% (p=0.02, HF+PBS vs HF+o- rMETase). Conclusion: The HF+ o-rMETase group had the same weight increase as untreated mice on a normal fat diet, demonstrating the potential for o-rMETase to eliminate the need for dieting to maintain normal body weight. [ABSTRACT FROM AUTHOR]

Background: In our previous study, monogalactosyl diacylglycerol (MGDG) purified from spinach was found to have cytotoxic effects in human cancer cell lines. This study further assessed whether MGDG can enhance the cytotoxic effects of radiation in human pancreatic cancer cells in vitro and in vivo. Methods: Glycoglycerolipids from spinach including MGDG were extracted from dried spinach. The cytotoxicity of MGDG were evaluated by the MTT assay using four human pancreatic cancer cell lines (MIAPaCa-2, AsPC-1, BxPC-3 and PANC-1) and normal human dermal fibroblasts (NHDFs). The effects of radiation and MGDG alone or in combination in MIAPaCa-2 cells was analyzed with the colony forming and apoptosis assays, western blotting and cell cycle and DNA damage analyses (γ-H2AX foci staining and comet assay). The inhibitory effects on tumor growth were assessed in a mouse xenograft tumor model. Results: MGDG showed dose- and time-dependent cytotoxicity, with half-maximal inhibitory concentrations (IC50) in PANC-1, BxPC-3, MIAPaCa-2 and AsPC-1 cells at 72 h of 25.6 ± 2.5, 26.9 ± 1.3, 18.5 ± 1.7, and 22.7 ± 1.9 µM, respectively. The colony forming assay revealed fewer MIAPaCa-2, BxPC-3 and AsPC-1 cell colonies upon treatment with both MGDG and radiation as compared to irradiation alone (P < 0.05). The combination of MGDG and radiation induced a higher proportion of apoptosis in MIAPaCa-2 cells; this effect was associated with increased mitochondrial release of cytochrome c and activation of cleaved poly (ADP-ribose) polymerase and caspase-3. DNA damage was detected and DNA repair mechanisms were more frequently impaired in cells receiving the combination treatment as compared to either one alone. Tumor growth was inhibited to a greater degree in mice treated by intratumoral injection of MGDG combined with irradiation as compared to either one alone (P < 0.05). Conclusions: This is the first report demonstrating that MGDG enhances the cytotoxicity of radiation to induce apoptosis of cancer cells in vitro and in vivo. Our findings indicate that this therapeutic combination can be an effective strategy for the treatment of pancreatic cancer. [ABSTRACT FROM AUTHOR]