Uptake Pathway of Styrene Maleic Acid Copolymer-Coated Lipid Emulsions Under Acidic Tumor Microenvironment

The purpose of this study was to elucidate and compare styrene maleic acid copolymer (SMA)-coated lipid emulsions (SMA emulsions) uptake pathway in vascular endothelial cells and surrounding cancer cells under not only neutral but also acidic pH, which is often observed in tumor microenvironment. DiI-labeled SMA emulsions were prepared using 1-palmitoyl-2-oleoyl-sn‑glycero-3-phosphocholine and triolein. In murine melanoma B16-BL6 (B16) cells and human umbilical vein endothelial cells (HUVEC), DiI-labeled SMA emulsions uptake under near-neutral (pH 7.4) and acidic (pH 6.0) conditions was determined by fluorescent analysis. SMA emulsions were taken up more efficiently into HUVEC than B16 cells under acidic condition in a temperature-dependent manner. Uptake study using endocytosis inhibitors showed that SMA emulsions were taken up by macropinocytosis and clathrin-mediated endocytosis in B16 cells. In HUVEC, however, they were taken up by clathrin- and caveolae-independent, but dynamin-dependent pathway. SMA emulsions would be internalized efficiently into vascular endothelial cells as well as cancer cells under acidic microenvironment via different endocytosis pathways. SMA emulsions could be a promising drug delivery carrier for anti-angiogenic drugs.

3-deazaneplanocin A, a histone methyltransferase inhibitor, improved the chemoresistance induced under hypoxia in melanoma cells

One of common characteristics of solid tumors is low O2 level, so-called hypoxia, which plays a critical role in chemoresistance. Epigenetic mechanism such as DNA methylation and histone modification is involved in cancer development and progression. There is ample evidence that epigenetic drugs reversed acquired chemoresistance in cancer cells under normal O2 level, normoxia. However, it remains unknown whether epigenetic drugs improve acquired chemoresistance under hypoxia. The aim of our study was to investigate whether epigenetic drugs can improve the chemoresistance induced under hypoxia in cancer cells. In murine melanoma B16-BL6 (B16) cells, the culture under hypoxia, 1%O2 caused the elevated expression of hypoxia-inducible factor-1α (HIF-1α) and its target genes. The chemoresistance to 7-ethyl-10-hydroxycamptothecin (SN-38, the active metabolite of irinotecan) was also acquired under hypoxia in B16 cells. In addition, as epigenetic mechanisms, the protein expression of the enhancer of zeste homolog 2 (EZH2), histone methyltransferase and its target histone H3 trimethylation at lysine 27 (H3K27Me3) level increased under hypoxia. The induction of H3K27Me3 under hypoxia was suppressed by EZH2 siRNA and 3-deazaneplanocin A (DZNep), an EZH2 inhibitor. Furthermore, both EZH2 siRNA and DZNep significantly reduced the cell viability after SN-38 treatment and improved the chemoresistance to SN-38 under hypoxia. These results indicated that the chemoresistance to SN-38 under hypoxia would arise from epigenetic mechanism, H3K27Me3 elevation due to EZH2 induction. In conclusion, a histone methyltransferase EZH2 inhibitor, DZNep was capable of tackling acquired chemoresistance via the suppression of histone methylation induced under hypoxic tumor microenvironment.

Long-Term Outcomes in a Phase II Study of Hypofractionated IGRT 60Gy/ 20F in Patients with Isolated Lymph Node Recurrence after Surgery for Esophageal Carcinoma

PURPOSE/OBJECTIVE(S)

In oligo metastases in lymph node recurrence after surgery for esophageal cancer, since SBRT (BED>100 Gy10) to mediastinal and abdominal lymph node lesions was not an option due to toxicities in the organs at risk (OAR) such as vessels and gastrointestinal tract, we performed a prospective cohort study of hypofractionated IGRT for isolated lesions. The primary end-points of this study are disease specific survival (DSS) and late treatment toxicities.

MATERIALS/METHODS

From 2011 to 2021, 60 Gy/20F/4-4.5wks (78 Gy10) hypofractionated IGRT was performed in a total ITT population of 70 patients after radical surgery (67 cases) and ESD (3 cases), who were diagnosed by CT/PET-CT as having solitary lymph node recurrence (62 cases) or up to 2 adjacent nodes (8 cases). The mean time from surgery to recurrence was 17.9 months (SD 18.1) with a mean age of 67.5 years (SD 9.3), and male to female ratio was 62:8. Pathological results showed that 63 patients (90%) had squamous cell carcinoma. The mean maximum diameter of lesions was 2.5 cm (SD; 1.1 cm). And 51 cases (73%) were treated with CRT concurrently using 5FU plus CDDP (FP), and the rest were treated with RT alone. Lymph node location was lower neck or upper mediastinum in 42 cases, middle and lower mediastinum in 16 cases, and abdomen in 12 cases, respectively. Treatment planning was performed by taking 4DCT fusing PET or MRI images. The Kaplan-Meier method and the Cox proportional hazards regression model were used for overall survival (OS), DSS, and progression free survival (PFS).

RESULTS

The mean observation period was 38 months. Primary efficacy was CR in 45 cases (64%), but CR was maintained only in 29 cases (41%). Twenty-two of the 70 patients were relapse-free. OS were 53% and 34% at 2 and 5 years, DSS were 56% and 38% at 2 and 5 years, and PFS were 40% and 39% at 2 and 5 years, respectively. The site of first recurrence was the same or adjacent lymph nodes in 33 cases (47%) and distant metastases in 9 cases (13%). Number of tumors (1 vs. 2), age, and CRT were not significant prognostic factors for OS, DSS, or PFS. In a multivariate analysis, the time from surgery to recurrence ≥12 months was the only significant prognostic factor for PFS (p = 0.018, HR0.50). The same multivariate analysis showed that the only significant prognostic factor for DSS was the location of the recurrent lymph node in the neck and upper mediastinal regions (p = 0.009, HR 0.59). The only late adverse events of Grade 2 or higher were Grade 2 pleural effusion (little and transient) in 6 cases and Grade 2 radiation pneumonitis in 1 case. No acute adverse events were observed other than hematologic toxicity due to FP administration.

CONCLUSION

In locally advanced esophageal cancer, a relatively reliable regional lymph node dissection is often performed, so there is still a chance to aim for cure in cases of solitary recurrence. We found that if the lesion is solitary, localized RT of about 60 Gy/20F/4-4.5 weeks with IGRT can achieve a long-term survival in 40% of patients without any significant adverse events.

FNAIT pathogenesis determined by serial analysis of three subsequent pregnancies of a woman with severe fetal and neonatal alloimmune thrombocytopenia (FNAIT) with anti-HPA-4b and anti-HPA-5b alloantibodies in the first sibling

BACKGROUND

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is caused by anti-HPA alloantibody, and anti-HPA-4b is the most common cause in Japanese. Anti-HPA-5b is frequently detected in pregnant women, but it is still controversial whether anti-HPA-5b causes severe FNAIT.

CASE PRESENTATION

A Japanese woman with anti-HPA-4b and anti-HPA-5b alloantibodies delivered a baby with severe FNAIT who was both HPA-4b and HPA-5b incompatible. We carefully monitored the patient's following three pregnancies (the second and the fourth siblings were HPA-4b incompatible and HPA-5b compatible; the third sibling was both HPA-4b and HPA-5b compatible). FNAIT was not observed in all three siblings, although a modest decrease in cord blood platelet count was observed in the HPA-4b incompatible siblings compared to the HPA-4b compatible sibling. Serial monitoring of anti-HPA titer showed that anti-HPA-4b markedly decreased in late pregnancy and recovered after delivery of the HPA-4b incompatible siblings, but these decreases were not observed during the mother's pregnancy with the HPA-4b compatible sibling. In contrast, anti-HPA-5b remained at a high titer during pregnancy with all three siblings.

CONCLUSION

Our data indicate that dynamic changes of anti-HPA-4b occur during pregnancy and strongly suggest that anti-HPA-5b was mainly responsible for severe FNAIT in this case.

Preparation and Evaluation of Paclitaxel-Loaded PEGylated Niosomes Composed of Sorbitan Esters

Niosomes are non-ionic surfactant (NIS)-based bilayer vesicles and, like liposomes, have great potential as drug-delivery systems. Our previous study revealed that polyethylene glycol (PEG) niosomes using different sorbitan ester (Span) surfactants (sorbitan monoester, Span 20, 40, 60, 80; sorbitan triester, Span 65) distributed within tumors similarly to PEG liposomes. The aim of this study was to encapsulate efficiently an anti-cancer drug, paclitaxel (PTX) into Span PEG niosomes, and evaluate PTX release profiles and anti-tumor efficacy of PTX-loaded Span PEG niosomes. Niosome sizes ranged between 100-150 nm, and the PTX encapsulation efficiency was more than 50%. All niosomes examined, in the presence of serum, yielded sustained PTX-release profiles. PTX release at 24 and 48 h from Span 80 PEG niosomes was significantly the highest among the other Span PEG niosomes examined. In C26 tumor-bearing mice, PTX-loaded Span 40 PEG niosomes (the lowest PTX release in vitro) suppressed tumor growth while PTX-loaded Span 80 PEG niosomes (the highest PTX release in vitro) did not. Thus, we succeeded in the control of PTX release from Span PEG niosomes by modifying the component of niosomes, and it influenced the effects of drugs loaded into niosomes. This demonstrates that the excellent NIS physicochemical properties of Spans make them an ideal candidate for anti-cancer drug-carrier niosomes.

Suppression of Phagocytic Activity Leads to the Efficient Surface Modification of Macrophages with Liposomes for Developing a Biomimetic Drug Delivery System

Macrophages selectively infiltrate the lesion sites of several diseases, including cancers, and, thus, have attracted attention as a biomimetic drug delivery carrier. To achieve the efficient drug loading of macrophages with minimal cytotoxicity, drugs are preferably encapsulated into nanoparticles, such as liposomes, and modified on the surface of macrophages rather than being incorporated into cells. However, liposomes are rapidly taken up by macrophages after binding to the cell surface because of their strong phagocytic activity. To overcome this, we herein attempted to modify the surface of macrophages with liposomes by suppressing their phagocytic activity using a pretreatment with anionic liposomes. We confirmed that 1,2-distearoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DSPG)- and cholesterol-rich anionic liposomes were efficiently taken up by RAW264.7 murine macrophage-like cells. Furthermore, the cellular uptake of anionic liposomes by RAW264.7 cells was higher in the absence of fetal bovine serum (FBS) than in its presence. Moreover, the viability of RAW264.7 cells was maintained above 90% when cells were incubated with anionic liposomes for 3 h, whereas viability was markedly decreased after a 24-h incubation. Based on these results, we pretreated RAW264.7 cells by an incubation with DSPG- and cholesterol-rich liposomes for 3 h in the absence of FBS. This pretreatment significantly inhibited the internalization of other liposomes, which subsequently bound to the cell surface. Therefore, we succeeded in modifying the surface of macrophages with liposomes, and liposome-modified macrophages have potential as a biomimetic active drug delivery carrier.

Combination of azacytidine and curcumin is a potential alternative in decitabine-resistant colorectal cancer cells with attenuated deoxycytidine kinase

Decitabine (DAC), a DNA methyltransferase (DNMT) inhibitor is a novel anti-cancer drug regulating epigenetic mechanisms. Similar to conventional anti-cancer drugs, drug resistance to DAC also has been reported, resulting in tumor recurrence. Our previous study using colorectal cancer HCT116 cells found the decrease in deoxycytidine kinase (dCK) (activation enzyme of DAC) and the increase in cytidine deaminase (inactivation enzyme of DAC) in acquired DAC-resistant HCT116 (HCT116/DAC) cells. The aim of our study was to clarify the involvement of dCK and CDA in DAC resistance. In order to tackle DAC resistance, it was also examined whether other DNMT inhibitors such as azacytidine (AC) and polyphenols are effective in DAC-resistant cancer cells. When dCK siRNA was transfected into HCT116 cells, IC₅₀ value of DAC increased by about 74-fold and reached that of HCT116/DAC cells with attenuated dCK. dCK siRNA to HCT116 cells also abolished DNA demethylation effects of DAC. In contrast, CDA siRNA to HCT116 cells did not influence the efficacy of DAC. In addition, CDA siRNA to HCT116/DAC cells with increased CDA did not restore the compromised effects of DAC. These results suggested that attenuated dCK but not increased CDA mainly contributed to DAC resistance. Regarding dCK in HCT116/DAC cells, a point mutation with amino acid substitution was observed while the product size and expression of mRNA coding region did not change, suggesting that dCK protein was decreased by post-transcriptional regulation. AC and polyphenols showed no cross-resistance in HCT116/DAC cells. AC but not polyphenols exerted DNA demethylation effect. Among polyphenols, curcumin (Cur) showed the most synergistic cytotoxicity in combination with AC while DNA demethylation effect of AC was partly maintained. Taken together, combination of AC and Cur would be a promising alternative to tackle DAC resistance mainly due to attenuated dCK.

Optimization of Analytical Conditions for Hydrophilic Nucleic Acids Using Mixed-Mode and Reversed-Phase Pentabromobenzyl Columns

The aim of this study was to investigate appropriate analytical conditions for hydrophilic nucleosides and nucleotides (monophosphates and triphosphates) by HPLC methods using a mixed-mode AX-C18 column with anion-exchange and hydrophobic interactions by quaternary ammonium and C18, respectively, and a reversed-phase pentabromobenzyl (PBr) column with dispersion force and hydrophobic interactions by PBr group. The higher compound polarity led to stronger retention on AX-C18 (triphosphates > monophosphates > nucleosides). AX-C18 demonstrated feasible retention of nucleotides via anion-exchange interaction by increasing the salt and methanol concentrations. In contrast, on PBr, the lower compound polarity led to stronger retention. On PBr, feasible retention of both nucleosides and nucleotides was obtained via dispersion interactions with purine and pyrimidine rings by increasing the methanol concentration. Regarding the pH of phosphate buffer used as the mobile phase, pH 7.0 should be used in measuring nucleoside triphosphates on AX-C18, whereas pH 2.5 is better suited for measuring nucleotides on PBr. In terms of selectivity to highly hydrophilic nucleotides, the mixed-mode AX-C18 column had an advantage over the reverse-phase PBr column. In contrast, PBr column was more versatile than the AX-C18 column. Taken together, HPLC analyses of nucleosides and nucleotides should be carried out by optimizing the interactions between the stationary phase and nucleic acids.

miR-33a-5p in small extracellular vesicles as non-invasive biomarker for oxaliplatin sensitivity in human colorectal cancer cells

microRNAs (miRNAs) contained in small extracellular vesicles (sEVs) are candidates for non-invasive biomarkers. Oxaliplatin (L-OHP) has been approved for advanced colorectal cancer (CRC) chemotherapy. However, the response to L-OHP differs among CRC patients. In addition, CRC cells often acquire the resistance to L-OHP. This study aimed at the prediction of L-OHP sensitivity by measuring extracellular miRNAs levels. Firstly, we compared intracellular miRNAs expressions in L-OHP-sensitive CRC cells (SW620 and HCT116 cells) with those in acquired and intrinsic L-OHP-resistant cells. In microarray and real-time RT-PCR analyses, the intracellular miR-33a-5p, miR-210–3p, and miR-224–5p expressions were lower in acquired and intrinsic L-OHP-resistant CRC cells than sensitive cells. Furthermore, in SW620 cells, L-OHP sensitivity was decreased by miR-33a-5p inhibitor. On the other hand, miR-210–3p or miR-224–5p inhibitor did not affect L-OHP sensitivity in SW620 cells. Secondly, the amount of miR-33a-5p, miR-210–3p, and miR-224–5p in sEVs was compared. The amount of miR-33a-5p and miR-210–3p in sEVs secreted from acquired and intrinsic L-OHP-resistant cells tended to be small. miR-224–5p was not detected in sEVs secreted from three types of CRC cells examined. To the best of our knowledge, this is the first study demonstrating that miR-33a-5p and/or miR-210–3p in sEVs would be candidates for biomarkers of L-OHP sensitivity. In particular, miR-33a-5p is a promising candidate because it would be directly involved in L-OHP sensitivity.

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miR-33a-5p was down-regulated in oxaliplatin-resistant colorectal cancer cells.

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Reduction of intracellular miR-33a-5p expression caused oxaliplatin resistance.

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miR-33a-5p amount in small extracellular vesicles from resistant cells was small.

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miR-33a-5p is a candidate for non-invasive biomarker of oxaliplatin sensitivity.

[Approaches for Class Preparation Using Qualitative Analysis by Coding-Survey in Technical English Course "Yakugaku-Eigo Nyumon"]

The purpose of this study was to examine how students prepare for the pharmaceutical technical English course "Yakugaku-Eigo Nyumon" by qualitative analysis. A sub-text, supplemental material was used to assist students with class preparation. Qualitative questionnaires on understanding and approaches for class preparation as well as review of class were analyzed in comparison with different academic performance levels on the final exam. The results of qualitative analysis of class preparation based on coding revealed that high-academic-performing students understood and adopted deep-processing approaches for the preparation of "English words" and "understanding of content" more often than low-academic-performing students. High-performing students attempted to not literally translate English sentences into Japanese while checking the English words with thinking and ingenuity, and to understand English sentences by drawing figures and thinking of relationships using previously learned knowledge. These approaches were not adopted by low-performing students. Furthermore, sub-text was one of the means for understanding by high-performing students, whereas it was essential for low-performing students to understand the content. Coding results on the review of class also showed that low-performing students were dependent mainly on sub-text for understanding. These results suggest that deep-processing approaches to both English and content of materials are necessary for deep understanding in "Yakugaku-Eigo Nyumon".

Numerical analysis of apparent decitabine uptake in HCT116 cells: Incorporation of a bidirectional first-order kinetic parameter for ENT1 transport and Michaelis-Menten parameters for subsequent phosphorylation

Decitabine (DAC), a DNA methylation inhibitor, is transported into cancer cells mainly via equilibrative nucleoside transporter 1 (ENT1) and subsequently phosphorylated by deoxycytidine kinase (dCK). We previously reported that apparent DAC uptake into cells may be described using a simple compartment model with clearance for facilitated diffusion (PS) and subsequent phosphorylation (CL_met). In the present study, time course of apparent intracellular [³H]-DAC uptake was analyzed numerically, and PS and CL_met values were calculated using the compartment model in human colon cancer HCT116 cells. PS at 0.1 μM [³H]-DAC was markedly decreased in the presence of 100 μM irinotecan or etoposide, while CL_met was markedly decreased in the presence of 100 μM cytarabine or gemcitabine. CL_met at 0.1-10 μM [³H]-DAC varied in a concentration-dependent manner and was described by Michaelis-Menten parameters K_m,met and V_max,met. In conclusion, DAC uptake mainly via ENT1 may be described by a bidirectional first-order kinetic parameter, while phosphorylation by dCK may be described by Michaelis-Menten parameters.

The critical role of urease in yogurt fermentation with various combinations of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus

The protocooperation between Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus relies on metabolite exchanges that accelerate acidification during yogurt fermentation. Conflicting results have been obtained in terms of the effect of the Strep. thermophilus urease and the NH₃ and CO₂ that it generates on the rate of acidification in yogurt fermentation. It is difficult to perform a systematic study of the effects of urease on protocooperation because it is necessary to distinguish among the direct, indirect, and strain-specific effects resulting from the combination of the strains of both species. To evaluate the direct effects of urease on protocooperation, we generated 3 urease-deficient mutants (ΔureC) of fast- and slow-acidifying Strep. thermophilus strains and observed the effects of NH₃ or CO₂ supplementation on acidification by the ΔureC strains. Further, we examined 5 combinations of 3 urease-deficient ΔureC strains with 2 CO₂-responsive or CO₂-unresponsive strains of L. bulgaricus. Urease deficiency induced a shortage of ammonia nitrogen and CO₂ for the fast- and slow-acidifying Strep. thermophilus and for the CO₂-responsive L. bulgaricus, respectively. Notably, the shortage of ammonia nitrogen had more severe effects than that of CO₂ on yogurt fermentation, even if coculture with L. bulgaricus masked the effect of urease deficiency. Our work established (1) that urease deficiency inhibits the fermentative acceleration of protocooperation regardless of the Strep. thermophilus and L. bulgaricus strain combinations, and (2) that urease is an essential factor for effective yogurt acidification.

Distinct effects of daratumumab on indirect and direct antiglobulin tests: a new method employing 0.01 mol/L dithiothreitol for negating the daratumumab interference with preserving K antigenicity (Osaka method)

BACKGROUND

There is an increasing demand for daratumumab (DARA), an immunoglobulin (Ig)G1κ monoclonal antibody (MoAb) that recognizes CD38, to manage relapsed or refractory multiple myeloma (MM) patients. However, DARA leads to positive and panreactive agglutination reactions in indirect antiglobulin tests (IATs) in vitro (the DARA interference). In addition, effects of DARA on red blood cells (RBCs) in vivo remains elusive.

STUDY DESIGN AND METHODS

To develop a new method to negate the DARA interference, the effects of various concentrations of dithiothreitol (DTT) on RBC CD38 and Kell antigenicity in combination with an automatic blood cell washing centrifuge were compared with the AABB standard procedure in parallel. Moreover, direct antiglobulin tests (DATs) for RBCs in DARA-treated MM patients were examined.

RESULTS

A quantity of 0.01 mol/L DTT as well as the AABB procedure (equivalent to 0.15 mol/L DTT in our procedure) markedly reduced the reactivity of phycoerythrin-mouse anti-CD38 MoAb and DARA with RBCs. In sharp contrast to the AABB procedure, 0.01 mol/L DTT partially preserved K antigenicity and allowed the determination of phenotype of K antigen even in the presence of the DARA interference. In contrast, DAT for RBCs obtained from MM patients showed a weak positive or negative reaction. Immunoblotting further indicated that DARA induced loss of CD38 in vivo.

CONCLUSION

A simple and reliable method to negate the DARA interference with partially preserving Kell antigenicity is proposed (Osaka method). CD38 antigenicity is susceptible to 0.01 mol/L DTT treatment even in the presence of DARA. Our data also demonstrate distinct effects of DARA on IAT in vitro and DAT in vivo.

Different Schedule-Dependent Effects of Epigenetic Modifiers on Cytotoxicity by Anticancer Drugs in Colorectal Cancer Cells

Limited information is currently available on how to apply epigenetic modifiers to current colorectal cancer (CRC) chemotherapy. The purpose of this study is to clarify the schedule-dependent effects of combined treatment with conventional anticancer drugs and epigenetic modifiers in human CRC cells. Cytotoxicity in 4 CRC cell lines (SW480, HT29, SW48, and HCT116) was measured using the WST-8 assay. As epigenetic modifiers, 3 DNA methyltransferase (DNMT) inhibitors such as decitabine (DAC), azacytidine (AC), and zebularine (Zeb), and 3 histone deacetylase (HDAC) inhibitors including trichostatin A (TSA), suberoylanilide hydroxamic acid (SAHA), and valproic acid (VPA) were used. Combination effects were analyzed by the isobologram method. SW480 cells showed the lowest sensitivity to the anticancer drugs 5-fluorouracil, SN-38 (the active form of irinotecan), and oxaliplatin. In SW480 cells, epigenetic modifiers other than VPA showed the most significant synergistic effects when used before anticancer drugs, while VPA showed synergistic effects in co- or post-treatment. In the 3 other CRC cells, synergistic effects were less frequent and weaker. The dose of anticancer drugs may be reduced by combining epigenetic modifiers in SW480 cells, which are less sensitive to anticancer drugs, unlike the more sensitive HT29, SW48, and HCT116 cell lines. These results provide useful information for understanding how to incorporate epigenetic modifiers into current CRC chemotherapy.

Monophosphorylation by deoxycytidine kinase affects apparent cellular uptake of decitabine in HCT116 colon cancer cells

Decitabine (DAC), a nucleoside-related DNA methylation inhibitor, is taken up into cancer cells via equilibrative nucleoside transporter 1 (ENT1), and is then monophosphorylated by deoxycytidine kinase (dCK). In the present study, we examined the contribution of dCK to the uptake of DAC in HCT116 colon cancer cells. Irinotecan and etoposide inhibited the uptake of [³H]-uridine and [³H]-DAC at 10 s and 5 min, while cytarabine and gemcitabine only inhibited that of [³H]-DAC at 5 min. Irinotecan and etoposide inhibited [³H]-DAC uptake in negative control small interfering RNA (siRNA)- or dCK siRNA-transfected cells at 10 s, whereas cytarabine and gemcitabine did not. Cytarabine and gemcitabine inhibited DAC monophosphate generation by the cytosolic proteins of HCT116 cells and recombinant human dCK protein, assessed using polyethylenimine cellulose thin-layered chromatography. Simulations using simple kinetic models showed that apparent DAC uptake in dCK and ENT1 siRNA-treated cells was attributed to its conversion to monophosphates or a decrease in the cellular flux, respectively, and that the apparent uptake of DAC in dCK-knockdown and ENT1-knockdown cells was similar at longer times, but differed at a very short time. These results suggest that the apparent uptake of DAC is affected by ENT1 and dCK in HCT116 cells.

Effects of Zebularine on Invasion Activity and Intracellular Expression Level of let-7b in Colorectal Cancer Cells

The effects of zebularine, a DNA methyltransferase inhibitor, on the invasion activity as well as intracellular expression level of let-7b, tumor suppressor microRNA, were examined in three human colorectal cancer (CRC) cell lines: SW480, SW620, and oxaliplatin-resistant SW620 (SW620/OxR). Zebularine suppressed the invasion activity of SW620 and SW620/OxR cells. The intracellular expression level of let-7b was up-regulated by zebularine in SW620 and SW620/OxR cells. The overexpression of let-7b by the transfection of let-7b mimic suppressed invasion activity in SW620 and SW620/OxR cells. These results suggest that zebularine may inhibit invasion activity by up-regulating the intracellular expression level of let-7b in high-invasive CRC cells.

Cellular Uptake of Decitabine by Equilibrative Nucleoside Transporters in HCT116 Cells

DNA hypermethylation, an epigenetic change that silences gene expression without altering nucleotide sequences, plays a critical role in the formation and progression of colorectal cancers as well as in the acquisition of drug resistance. Decitabine (DAC), a DNA methyltransferase 1 inhibitor of nucleoside analogues, has been shown to restore gene expression silenced by hypermethylation. In the present study, the mechanisms underlying both uridine and DAC uptake were examined in the human colon cancer cell line HCT116. Real-time polymerase chain reaction analysis revealed that ENT1 mRNA was the most abundant among the nucleoside transporters examined in HCT116 cells. The ENT1 protein was detected in the membrane fraction, as determined by Western blotting. The uptake of uridine or DAC was time- and concentration-dependent, but also Na(+)-independent. The uptake of these agents was inhibited by S-(4-nitrobenzyl)-6-thioinosine (NBMPR), an inhibitor of equilibrative nucleoside transporters (ENTs), and was also decreased in cells treated with ENT1 small interfering RNA. The uptake of both uridine and DAC was inhibited by uridine, cytidine, adenosine, or inosine, while that of DAC was also inhibited by thymidine. The expression of MAGEA1 mRNA, the DNA of which was methylated in HCT116 cells, was increased by DAC treatment, and this increment was attenuated by concomitant treatment with NBMPR. The IC50 value of DAC was also increased in the presence of NBMPR. These results suggest that DAC is mainly taken up by ENT1 and that this uptake is one of the key determinants of the activity of DAC in HCT116 cells.

Effects of Decitabine on Invasion and Exosomal Expression of miR-200c and miR-141 in Oxaliplatin-Resistant Colorectal Cancer Cells

The effects of decitabine (DAC), a DNA methyltransferase (DNMT) inhibitor, on metastasis and exosomal expression of microRNAs were examined in SW620/OxR cells, a human colorectal cancer (CRC) cell line (SW620) with acquired resistance to oxaliplatin. This cell line shows an invasive phenotype by epithelial-mesenchymal transition. Two CRC cell lines, SW480, derived from primary CRC, and SW620, derived from lymph node metastasis, which were obtained from the same patient, as well as SW620/OxR, were also used in the present study. Cytarabine (Ara-C), a non-DNMT-inhibiting cytidine analog, was used as negative control of DAC. No significant difference was observed in the invasion abilities of SW480 cells treated with DAC or Ara-C. On the other hand, invasion ability was suppressed by treatment with DAC in SW620 and SW620/OxR cells. Up-regulated expression of E-cadherin, microRNA-200c (miR-200c), and miR-141 following DAC treatment indicated the acquisition of epithelial cell-like characteristics in SW620 and SW620/OxR cells. Exosomal expression levels of miR-200c and miR-141 were also up-regulated by DAC treatment in SW620 and SW620/OxR but not in SW480 cells. This increase in exosomal miRNA expression negatively correlated with invasion ability. These results suggest that DNA demethylation treatment caused acquisition of epithelial cell-like characteristics in SW620 and SW620/OxR cells. Furthermore, the observed increased exosomal expression of miR-200c and miR-141 may be an indicator or biomarker candidate for mesenchymal-epithelial transition of CRC cells.

Induction of epithelial-mesenchymal transition and down-regulation of miR-200c and miR-141 in oxaliplatin-resistant colorectal cancer cells

Epithelial-mesenchymal transition (EMT) and changes in the expression of the microRNA-200 (miR-200) family were examined in the human colorectal cancer (CRC) cell line SW620 with acquired oxaliplatin (L-OHP) resistance. Two CRC cell lines, SW480, derived from primary CRC, and SW620, derived from lymph node metastasis, which were obtained from the same patient, were used in the present study. L-OHP-resistant SW620 cells were obtained by exposure to L-OHP for 155 d. The concentration of L-OHP was increased to 80 µM in a stepwise manner. The IC50 value of L-OHP was increased 16-fold in L-OHP-resistant SW620 cells, which also displayed mesenchymal cell-like characteristics, such as the down-regulation of E-cadherin and up-regulation of vimentin. However, L-OHP-resistant SW480 cells were not obtained when the concentration of L-OHP was increased in a similar stepwise manner. The expression levels of members of the miR-200 family (miR-200a, miR-200b, miR-429, miR-200c, and miR-141) were significantly higher in SW480 cells than in SW620 cells. The expression levels of miR-200c and miR-141 were significantly lower in L-OHP-resistant SW620 cells than in control SW620 cells. L-OHP-resistant SW620 cells did not exhibit cross-resistance to other anti-cancer drugs used to treat CRC, such as 5-fluorouracil, irinotecan, and the active metabolite of irinotecan (SN-38). These results suggest that the down-regulated expression of miR-200c and miR-141 plays a role in selective resistance to L-OHP and EMT in CRC cells during repeated treatments with L-OHP.

A case of neonatal alloimmune thrombocytopenia in the presence of both anti-HPA-4b and anti-HPA-5b antibody: clinical and serological analysis of the subsequent pregnancy

Neonatal alloimmune thrombocytopenia (NAIT) is induced by maternal alloantibodies raised against fetal platelet antigens inherited from the paternal parent. In contrast to Caucasians, in Asians, predominantly in Japanese, most frequently detected antibodies in NAIT are anti-HPA-4b and anti-HPA-5b. In some NAIT cases multiple alloantibodies are detected. In such cases it is very difficult to determine which antibody is the dominant antibody in NAIT. In this case report, we describe a NAIT case (first sibling) with severe thrombocytopenia and cephalhematoma in the presence of both anti-HPA-4b and anti-HPA-5b antibodies in the maternal serum. We carefully examined titers of anti-HPA antibodies during the subsequent pregnancy with HPA-4b-positive and HPA-5b-negative fetus determined by amniocentesis at gestational week 16. We administered IVIG (1 g/kg/w) to the mother from gestational week 32 to 35. The mother subsequently delivered a second sibling with normal platelet count by cesarean section. Although we could not completely rule out the involvement of anti-HPA-4b, our findings suggested that anti-HPA-5b was implicated in the NAIT in the first sibling.

Immunohistochemical localization of aggresomal proteins in glial cytoplasmic inclusions in multiple system atrophy

AIMS

Multiple system atrophy (MSA) is pathologically characterized by the formation of α-synuclein-containing glial cytoplasmic inclusions (GCIs) in oligodendrocytes. However, the mechanisms of GCI formation are not fully understood. Cellular machinery for the formation of aggresomes has been linked to the biogenesis of the Lewy body, a characteristic α-synuclein-containing inclusion of Parkinson's disease and dementia with Lewy bodies. Here, we examined whether GCIs contain the components of aggresomes by immunohistochemistry.

METHODS

Sections from five patients with MSA were stained immunohistochemically with antibodies against aggresome-related proteins and analysed in comparison with sections from five patients with no neurological disease. We evaluated the presence or absence of aggresome-related proteins in GCIs by double immunofluorescence and immunoelectron microscopy.

RESULTS

GCIs were clearly immunolabelled with antibodies against aggresome-related proteins, such as γ-tubulin, histone deacetylase 6 (HDAC6) and 20S proteasome subunits. Neuronal cytoplasmic inclusions (NCIs) were also immunopositive for these aggresome-related proteins. Double immunofluorescence staining and quantitative analysis demonstrated that the majority of GCIs contained these proteins, as well as other aggresome-related proteins, such as Hsp70, Hsp90 and 62-kDa protein/sequestosome 1 (p62/SQSTM1). Immunoelectron microscopy demonstrated immunoreactivities for γ-tubulin and HDAC6 along the fibrils comprising GCIs.

CONCLUSIONS

Our results indicate that GCIs, and probably NCIs, share at least some characteristics with aggresomes in terms of their protein components. Therefore, GCIs and NCIs may be another manifestation of aggresome-related inclusion bodies observed in neurodegenerative diseases.

Loss of multidrug and toxin extrusion 1 (MATE1) is associated with metformin-induced lactic acidosis

BACKGROUNDS AND PURPOSE

Lactic acidosis is a fatal adverse effect of metformin, but the risk factor remains unclear. Multidrug and toxin extrusion 1 (MATE1) is expressed in the luminal membrane of the kidney and liver. MATE1 was revealed to be responsible for the tubular and biliary secretion of metformin. Therefore, some MATE polymorphisms, that cause it to function abnormally, are hypothesized to induce lactic acidosis. The purpose of this study is to clarify the association between MATE dysfunction and metformin-induced lactic acidosis.

EXPERIMENTAL APPROACH

Blood lactate, pH and bicarbonate ion (HCO(3) (-) ) levels were evaluated during continuous administration of 3 mg·mL(-1) metformin in drinking water using Mate1 knockout (-/-), heterozygous (+/-) and wild-type (+/+) mice. To determine the tissue accumulation of metformin, mice were given 400 mg·kg(-1) metformin orally. Furthermore, blood lactate data were obtained from diabetic patients given metformin.

KEY RESULTS

Seven days after metformin administration in drinking water, significantly higher blood lactate, lower pH and HCO(3) (-) levels were observed in Mate1(-/-) mice, but not in Mate1(+/-) mice. The blood lactate levels were not affected in patients with the heterozygous MATE variant (MATE1-L125F, MATE1-G64D, MATE2-K-G211V). Sixty minutes after metformin administration (400 mg·kg(-1) , p.o.) the hepatic concentration of metformin was markedly higher in Mate1(-/-) mice than in Mate1(+/+) mice.

CONCLUSION AND IMPLICATIONS

MATE1 dysfunction caused a marked elevation in the metformin concentration in the liver and led to lactic acidosis, suggesting that the homozygous MATE1 variant could be one of the risk factors for metformin-induced lactic acidosis.

HLA class I antigens are possible prognostic factors in hepatocellular carcinoma

Thirty patients who underwent hepatectomy for the treatment of hepatocellular carcinoma (HCC) were examined for expression of HLA class I antigens on HCC cells by flow cytometry. The expression was found significantly lower in cases of stage IV compared with those of stage I or stage II (p<0.05), and in cases of intrahepatic metastases compared with those without metastases (p<0.001). In cases of non-curative hepatectomy, the expression of HLA class I antigens was lower compared with those treated by curative resection. Postoperative cumulative disease-free survival rates were well correlated with the expression rate of HLA class I antigens (p<0.05). Expression of HLA class I antigens on HCC may indicate low malignancy and better prognosis.

Immunohistochemical demonstration of increased prostaglandin F₂α levels in the rat hippocampus following kainic acid-induced seizures

Prostaglandin (PG) F(2α) is one of the major prostanoids biosynthesized by cyclooxygenases (COXs) from arachidonic acid. Although it has been reported that there is a selective surge in PGF(2α) production in the hippocampus during kainic acid (KA)-induced seizure activity, the precise intra-hippocampal distribution of PGF(2α) has not been elucidated due to the paucity of effective histological techniques for detecting PGs in tissues. We investigated the tissue distribution of PGF(2α) in the rat hippocampus 30 min after KA injection by developing fixation and immunohistological-staining methods. To detect PGF(2α) directly on histological sections, we used systemic perfusion fixation with water-soluble carbodiimide fixative, followed by immersion of the brains in Zamboni's fixative. We then performed immunofluorescence staining with anti-PGF(2α) antibody, with negative control experiments used to confirm the staining specificity. Definitive immunolabeling for PGF(2α) was evident most markedly in pyramidal cells of the hippocampal cornu Ammonis (CA) 3 sector and neurons of the hilus in KA-treated rats. Immunolabeling for PGF(2α) was also evident in granule cells of the dentate gyrus. Double immunfluorescence staining revealed that PGF(2α)-immunopositive neurons expressed cytosolic phospholipases A(2), COX-2, and FP receptor. These results suggest that the major source of PGF(2α) production immediately after KA injection was neurons of the hippocampal CA3 sector, hilus and dentate gyrus. These neurons exert PGF(2α)-mediated functions via FP receptors in an autocrine/paracrine manner and may play pathophysiological roles in the acute phase (30 min) of excitotoxicity.

Risk of perforation during dilation for esophageal strictures after endoscopic resection in patients with early squamous cell carcinoma

BACKGROUND AND STUDY AIMS

Growing evidence suggests that esophageal stricture frequently develops after endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) in early esophageal cancer patients, with an incidence proportional to the greater extent of mucosal defects resulting from improved EMR/ESD techniques. There seems to be a potential risk of perforation during bougienage in such patients.

PATIENTS AND METHODS

648 stricture dilations for 78 lesions in 76 patients were consecutively included. The outcomes after combined use of Maloney and Savary wire-guided bougienage for esophageal strictures after EMR/ESD were analyzed in a single-institute retrospective case series study. The perforation rate was determined and risk factors for perforation were identified.

RESULTS

Patients underwent a median of 5.0 dilation procedures performed over a median 3.0 months for post-EMR/ESD strictures. Initial dilation was done a median 14 days following endoscopic resection. Perforations developed in seven patients (7/648 dilation procedures, 1.1%), all in the lower esophagus, and bleeding occurred in one patient (0.1% dilations). Two independent risk factors for development of perforation during dilation therapy for post-EMR/ESD stricture were identified: multiple dilations (odds ratio [OR] 1.2; P=0.012), and lower site of stricture (OR 12.8; P=0.043). Dysphagia was ameliorated by the dilations, and no patient required surgery.

CONCLUSIONS

A specific emerging risk of perforation in dilation therapy for post-EMR/ESD strictures was identified. Carefully planned treatment is necessary in patients with severe post-EMR/ESD strictures especially strictures requiring multiple dilations or located in the lower esophagus.

Metformin suppresses hepatic gluconeogenesis and lowers fasting blood glucose levels through reactive nitrogen species in mice

AIMS/HYPOTHESIS

Metformin, the major target of which is liver, is commonly used to treat type 2 diabetes. Although metformin activates AMP-activated protein kinase (AMPK) in hepatocytes, the mechanism of activation is still not well known. To investigate AMPK activation by metformin in liver, we examined the role of reactive nitrogen species (RNS) in suppression of hepatic gluconeogenesis.

METHODS

To determine RNS, we performed fluorescence examination and immunocytochemical staining in mouse hepatocytes. Since metformin is a mild mitochondrial complex I inhibitor, we compared its effects on suppression of gluconeogenesis, AMPK activation and generation of the RNS peroxynitrite (ONOO(-)) with those of rotenone, a representative complex I inhibitor. To determine whether endogenous nitric oxide production is required for ONOO(-) generation and metformin action, we used mice lacking endothelial nitric oxide synthase (eNOS).

RESULTS

Metformin and rotenone significantly decreased gluconeogenesis and increased phosphorylation of AMPK in wild-type mouse hepatocytes. However, unlike rotenone, metformin did not increase the AMP/ATP ratio. It did, however, increase ONOO(-) generation, whereas rotenone did not. Exposure of eNOS-deficient hepatocytes to metformin did not suppress gluconeogenesis, activate AMPK or increase ONOO(-) generation. Furthermore, metformin lowered fasting blood glucose levels in wild-type diabetic mice, but not in eNOS-deficient diabetic mice.

CONCLUSIONS/INTERPRETATION

Activation of AMPK by metformin is dependent on ONOO(-). For metformin action in liver, intra-hepatocellular eNOS is required.

Enhanced inhibitory effects of TBT chloride on the development of F1 rats

Neurotoxicity is one of the major effects of tributyltin (TBT). The effects on the next generation of F(1) rats exposed to TBT via the placenta and their dams' milk may be stronger than those on adults. Pregnant Wister rats were exposed to TBT at 0 and 125 ppm in their food. Half of the female F(1) rats in both groups were exposed to TBT at 125 ppm in their food from 9 to 15 weeks of age. Female F(1) rats were divided into the following groups: the control-control (CC) group, with no exposure; the TBT-control (TC) group, exposed to TBT via the placenta and their dams' milk; the control-TBT (CT) group, exposed to TBT via their food from 9 to 15 weeks of age; and the TBT-TBT (TT) group, exposed to TBT via the placenta, their dams' milk, and their food (n = 10/group). After administration, an open-field test and prepulse inhibition (PPI) test were performed at 15 weeks of age. The mean body weights of the TC and TT groups were significantly lower than that of the CC group from 9 to 15 weeks of age. The mean relative thymus weight of the TC and TT groups was significantly lower than that of the CC group. In the open-field test, a marked decrease in the total locomotion distance was observed in the TT group. The mean values in the TT and TC groups were significantly lower than that in the CC group. For the locomotion distance between 15 and 20 min, the mean values in the CT, TC, and TT groups were significantly lower than that in the CC group. The mean locomotor distance between 25 and 30 min in the TT group was significantly lower than that in the CC and TC groups. The mean values of instances of wall rearing in the TC, CT, and TT groups were significantly lower than that in the CC group. The mean value of face washing or body washing in the TT group was significantly lower than that in the CT group. There were no significant differences in indexes of the PPI test. Exposure to TBT via the placenta and their dams' milk inhibited the development of F(1) rats, which continued after weaning. Inhibition of the rats' activity induced by exposure to TBT via the placenta and their dams' milk and/or via their food was suggested. The effects were most evident in the TT group.

Radical scavenging and singlet oxygen quenching activity of extracts from Indian seaweeds

Free radicals and singlet oxygen are responsible for oxidative stress related diseases and many natural compounds are known to have antioxidant properties. In this study, extracts from brown and red seaweeds of Indian origin were evaluated for their ability to scavenge different radicals and quench singlet oxygen. The crude extract in methanol and its fractions in different solvents were evaluated for their activity. The methanol extract and its fractions from brown seaweed exhibited higher 2,2'-azinobis(3-ethylbenzothizoline-6-sulfonic acid) radical scavenging activity with more than 90% scavenging in butanol and ethyl acetate fractions and correlated with polyphenol content. There was a significant difference (p≤0.001) in hydroxyl radical scavenging activity between different fractions of the same seaweed. Among the crude extracts, extract from Gracilaria corticata showed the highest (14.0%) activity. Crude extract from brown seaweeds showed higher peroxyl radical scavenging activity compared to red seaweeds. In fractions from brown seaweed extracts, highest activity was observed in ethyl acetate fraction (>88%) followed by hexane fraction (>40 %). Ethyl acetate fraction from crude extract showed higher inhibitory activity against hemoglobin induced linoleic acid oxidation. Singlet oxygen quenching activity of the crude extract from brown seaweed was lower (<13%) compared to red seaweeds (16.4-20.5%).