EtBr Staining Research Articles

Stat3 Inhibitors TTI-101 and SH5-07 Suppress Bladder Cancer Cell Survival in 3D Tumor Models.

Bladder cancer (BCa) is one of the most lethal genitourinary malignancies owing to its propensity for recurrence and poor survival. The biochemical pathway, signal transducer and activator of transcription 3 (STAT3), has gained significance as a molecular pathway that promotes proliferation, invasion, and chemoresistance. In this study, we explored the targeting of STAT3 with TTI-101 and SH5-07 in BCa and elucidated the mechanisms in three-dimensional (3D) spheroid and organoid models. We optimized the growth of spheroids from human, rat, and mouse BCa cell lines (J82, NBT-II, and MB49 respectively) and organoids from BBN (N-butyl-N-(4-hydroxybutyl)-nitrosamine)-induced rat bladder tumors. Cell viability was assessed using MTT and trypan blue assays. Intracellular ATP production, ROS production, and calcium AM (CA)/EtBr staining were used to measure the spheroid and organoid inhibition and mitochondrial function. Western blot analysis was performed to evaluate the pharmacodynamic markers involved in cell proliferation, apoptosis, cancer stem cells (CSCs), and STAT3 signaling in BCa. We found that targeting STAT3 (using TTI-101 and SH5-07) significantly reduced the proliferation of BCa spheroids and organoids, which was accompanied by decreased expression of pSTAT3, Cyclin D1, and PCNA. Our data also demonstrated that treatment with STAT3 inhibitors induced ROS production and cell death in BCa spheroids and organoids. STAT3 inhibition-induced cell death was associated with the activation of caspase 3/7 and PARP cleavage. Moreover, TTI-101 and SH5-07 target cancer stem cells by downregulating the expression of CD44 and CD133 in 3D models. This study provides the first evidence for the prevention of BCa with small-molecule inhibitors TTI-101 and SH5-07 via suppression of CSCs and STAT3 signaling.

Exploring the Cytotoxic and Anticancer Potential of Naringin on Oral Cancer Cell Line.

Introduction Oral cancer is the most persistent, aggressive primary malignant sarcoma that is globally prevalent. Though chemotherapy is the only treatment option, it has not progressed for years to overcome its detrimental side effects. Introducing novel therapeutic techniques to improve effectiveness is the need of the hour. Aim This study aimed to investigate the pro-apoptoticeffects of naringin in oral cancer cell lines. Methodology The cell viability of oral cancer cells treated with naringin was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Naringin was given tooral cancer cells (KB-1) in concentrations ranging from 20 to 200 µM/mL for 24 hours. A phase-contrast microscope is used to examine cell morphology changes. Ethidium bromide (EtBr) staining was employed to study nuclear morphological alterations in oral cancer cells. The apoptotic nuclei were viewed under a fluorescent microscope. To determine pro-apoptotic levels, quantitative real-time polymerase chain reaction (PCR) gene expression analysis was performed to evaluate the expression of transforming growth factor-beta (TGF-β), suppressor of mothers against decapentaplegic 2 (SMAD2), tumor necrosis factor alpha (TNFα), and nuclear factor kappa B (NFκB). A scratch wound healing experiment was used to evaluate naringin's anti-migratory properties. Results Our study found that naringin treatment significantly reduced cell viability in oral cancer cells compared to the control group (p < 0.05). In oral cancer cells, we found an inhibitory concentration (IC50) of 125.3 μM/mL. Following treatment, fewer cells were present, and those that were present shrunk and displayed cytoplasmic membrane blebbing. The EtBr staining reveals chromatin condensation and nuclear breakage in treated cells. The study found that naringin downregulates the expression of B-cell leukemia/lymphoma 2 (Bcl-2), TGF-β, SMAD2, TNFα, and NFκB and upregulates the expression of Bcl-2-associated agonist of cell death (BAD), Bcl-2-associated protein X (BAX), and caspase-3. Furthermore, when compared to control cells, naringin significantly reduced cell migration. Naringin treatment significantly promotes apoptosis and inhibits migration by altering the SMAD2 signaling pathway. Conclusion Overall, this study highlights the promising role of naringin as a pro-apoptotic and cytotoxic phytochemical regulating the gene expression of Bcl-2, TGF-β, SMAD2, TNFα, NFκB, BAD, BAX, and caspase-3, thereby treating oral cancer.

The therapeutic efficacy of silver loaded rhenium disulfide nanoparticles as a photothermal agent for cancer eradication

Cancer is a life-threatening disease when it is diagnosed at a late stage or treatment procedures fail. Inhibiting cancer cells in the tumor environment is a significant challenge for anticancer therapy. The photothermal effects of nanomaterials are being studied as a new cancer treatment. In this work, rhenium disulfide (ReS2) nanosheets were made by liquid exfoliation with gum arabic (GA) and coated with silver nanoparticles (AgNPs) to produce reactive oxygen species that destroy cancer cells. The synthesized AgNP-GA-ReS2 NPs were characterized using UV, DLS, SEM, TEM, and photothermal studies. According to the DLS findings, the NPs were about 216 nm in size and had a zeta potential of 76 mV. The TEM and SEM analyses revealed that the GA-ReS2 formed single-layered nanosheets on which the AgNPs were distributed. The photothermal effects of the AgNP-GA-ReS2 NPs at 50 μg/mL were tested with an 808 nm laser at 1.2 W cm−2, and they reached 55.8 °C after 5 min of laser irradiation. MBA-MB-231 cells were used to test the cytotoxicity of the newly designed AgNP-GA-ReS2 NPs with and without laser irradiation for 5 min. At 50 μg/mL, the AgNP-GA-ReS2 showed cytotoxicity, which was confirmed with calcein and EtBr staining. The DCFH-DA and flow cytometry analyses demonstrated that AgNP-GA-ReS2 nanosheets under NIR irradiation generated ROS with high anticancer activity, in addition to the photothermal effects.

Abstract 5255: Effect of STAT3 inhibitors, TTI-101 and SH5-07, against bladder cancer in preclinical 3D tumor models

Abstract Bladder cancer (BC) is a lethal genitourinary malignancy associated with frequent recurrence and poor survival due to metastatic potential. Identification of key cancer cell signaling networks and developing promising agents is critical for effectively inhibiting tumor growth and progression. In many cancers, including bladder cancer (BC), signal transducer and activator of transcription 3 (STAT3) has emerged as an important molecular pathway due to its role in promoting proliferation, invasion, and chemoresistance. Thus, developing STAT3 targeting, orally bioavailable small molecule inhibitors may be helpful for the prevention of BC progression and improving the survival rate of patients with muscle invasive BC. Monolayer culture has limitations for drug testing. Therefore, spheroid and organoid culture are used extensively as they may mimic in-vivo drug response more accurately. The aim of our study is to examine the preclinical anticancer efficacy of STAT3 inhibitors [TTI-101 (C188-9) and SH5-07] in 3D (spheroid and tumoroid) invitro models of BC. We optimized the spheroid growth using various BC cell lines [human (J82), rat (NBT-II), and mouse (MB49) BC cells]. Similarly, tumoroids from rat (BBN-induced bladder tumors) and transgenic mice (UPII-SV40T) bladder tumors were developed. These spheroids and tumoroids were treated with various concentrations (0 - 50 μM range) of STAT3 inhibitors and evaluated for their viability [Calcein AM (CA) and EtBr staining], ATP production (CellTiter-Glo™ 3D), and ROS production (MitoSOXTM). Effect of drug treatment on biomarkers of cell proliferation, apoptosis, stemness, STAT3 signaling, and immune modulation was determined using western blotting and immunofluorescence. Treatment with TTI-101 (0 - 50 μM or SH5-07 (0 - 50 μM) for 144 hrs resulted in significant reduction in the spheroids size (39-45% smaller Vs untreated; p&amp;lt;0.0001), along with decreased ATP levels (20%-40%, p&amp;lt;0.05). MitoSOXTM staining suggested that STAT3 inhibitors treatment increased ROS production in BC cells. CA and EtBr staining revealed that TTI-101 and SH5-07 treatment resulted in increased cell death in BC spheroids compared to control. Decreased spheroids and organoids size also correlated with increased apoptotic marker (cleaved caspase-3) along with decreased cyclin D1, PCNA, and pSTAT3 protein expression. Drug treated BC spheroids/tumoroids also showed reduction in CD44 (BC stemness and invasion marker) and induction of cGAS-STING pathway (cGAS, STING, TBK1, and IRF3) in comparison to the control. These findings indicate that STAT3 inhibitors, TTI-101 and SH5-07, could inhibit bladder cancer by suppressing STAT3 pathway activation and therefore warrant further study in vivo. (Supported by P30 CA225520 and Kerley-Cade Endowed Chair) Citation Format: Surya P. Singh, Gopal Pathuri, Adam Asch, Brian Cholewa, Robert Shoemaker, Chinthalapally V. Rao, Venkateshwar Madka. Effect of STAT3 inhibitors, TTI-101 and SH5-07, against bladder cancer in preclinical 3D tumor models. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5255.

KUALITAS DNA HASIL PURIFIKASI DARI SOSIS SAPI SEBAGAI BAHAN AUTENTIKASI HALAL BERBASIS MARKER GENETIK

This study aims to determine the effect of the preparation method and the number of samples on the quality of purified DNA from beef sausage. The study was conducted using a Randomized Block Design. The main factor is the sample preparation method which consists of P1: fresh sample; P2: oven-dried sample; and P3: Freeze-drying dry samples. Each treatment consisted of 4 groups, namely K1: sample weight 25 mg; K2: sample weight 50 mg; K3: sample weight 75 mg; and K4: sample weight 100 mg. Each treatment group was repeated 2 times so that the total sample was 24. The results showed that DNA purification using different preparation methods and sample weights was successfully carried out, as seen from the presence of DNA bands visualized on agarose gel with EtBr staining. The average DNA quality of the P1, P2, and P3 preparation methods were 1.60±0.90 ng/μl, 2.63±0.99 ng/μl, and 2.94 ±0.89, ng/μl respectively, with DNA purity 1.023 ±0.165, 0.937±0.148, and 1.014±0.163. The average DNA quality at K1, K2, K3, and K4 obtained DNA concentrations of 3.03±1.64 ng/μl, 3.15±0.74 ng/μl, 2.28± 1.66 ng/μl, and 2.54±1.50 ng/μl with a purity of 1.059±0.142, 0.981±0.130, 0.908±0.061, and 1.061± 0.215. The average total concentration of purified DNA from beef sausage was 2.75±1.28 ng/μl with a purity of 0.991±0.149. The results of variance showed that the treatment did not affect the concentration and purity of purified DNA from beef sausage. This study concludes that DNA purification from beef sausage can be carried out, but the preparation method and number of samples do not affect the quality and quantity of DNA.

Apoptosis Induction and Anticancer Activity of 2, 4-bis (1-phenylethyl) Phenol from Clerodendrum thomsoniae Balf.f. in vitro

Objectives: Plant phenolic have extended significance as a promising therapeutic candidate for several disorders including cancer. Apoptosis is a well-organized cell death that has importance in cancer research. The present study was aimed to isolate 2, 4-bis (1-phenylethyl) -phenol from Clerodendrum thomsoniae Balf.f. and evaluation of cytotoxicity on human breast cancer cells. Methods: MTT assay was used to estimate cell viability. Apoptosis was analyzed by Annexin V/PI staining, EtBr staining, cell cycle analysis and MMP assay. Results: In this study 2,4-bis (1-phenylethyl) -phenol was separated from aerial parts of C. thomsoniae and its structure was confirmed by different spectroscopic methods. The IC50 value was determined based on cell viability rates and the value was calculated as 12. 58 (μg/mL). Apoptosis analysis by annexin V/PI staining showed that died cells were stained as red fluorescence. The loss of mitochondrial potential as a result of the induction of apoptosis was noted. The EtBr assay showed early apoptotic cells, late apoptotic cells, necrotic cells and, dead cells with characteristic fluorescence. The apoptosis induction of 2, 4-bis (1-phenylethyl) –phenol was also noticed in Cell cycle analysis using flow cytometry. Conclusion: The outcome of this research work, we can conclude that 2, 4-bis (1-phenylethyl)-phenol may be a successful candidate for breast cancer therapy via apoptosis activation and farther in vivo studies are required to evaluate this compound for its safety and efficacy as a potential anticancer candidate.

Click chemistry based multicomponent approach in the synthesis of spirochromenocarbazole tethered 1,2,3-triazoles as potential anticancer agents

A series of spirochromenocarbazole tethered 1,2,3-triazoles were synthesized via click chemistry based one-pot, five component reaction between N-propargyl isatins, malononitrile, 4-hydroxycarbazole, aralkyl halides and sodium azide using cellulose supported CuI nanoparticles (Cell-CuI NPs) as the heterogeneous catalyst. Antiproliferative activity of all the synthesized compounds was investigated against panel of cancer cell lines such as MCF-7, MDA-MB-231, HeLa, PANC-1, A-549, and THP-1. Many of the synthesized compounds exhibited good anti-proliferative activity against breast (MCF-7 and MDA-MB-231) and cervical (HeLa) cancer cells with IC50 values less than 10 μM. In case of MCF-7 cells, among the nine compounds that showed good anti-proliferative activity, compounds 6f and 6j were found to be highly potent (IC50 = 2.13 μM and 4.80 μM, respectively). In case of MDA-MB-231, three compounds (6k, 6j and 6s) showed antiproliferative activity amongst which 6k was the most potent one (IC50 = 3.78 μM). On the other hand, in cervical cancer HeLa cells, compounds 6b, 6g, 6s and 6u showed excellent antiproliferative activity (IC50 = 4.05, 3.54, 3.83, 3.35 μM, respectively). All the compounds were found to be nontoxic to the human umbilical vein endothelial cells (HUVECs). AO and EtBr staining and fluorescence microscopy studies of the active compounds (IC50 < 5 μM) suggested that these compounds induce cell death by apoptosis.

Preliminary testing of SRAP primers in order to establish genetic diversity of Astragalus exscapus L. subsp. transsilvanicus (Schur) Nyár.

The Carpathian List of Endangered Species contains eight Astragalus species mentioned to be vulnerable or endangered. One of them is the endemic Astragalus. exscapus L. subsp. transsilvanicus (Schur) NyAir . , a rare perennial plant with only 24 populations remaining in the Transylvanian basin. Analysis of genetic diversity and population structure of this threatened subspecies is an important prerequisite for its conservation. The present study investigates eight different populations of A. exscapus using s equence r elated a mplified p olymorphism (SRAP) molecular markers. This technique is a relatively new PCR-based system, more reliable than r andom a mplified p olymorphic D NA (RAPD), and suitable for population structure analysis. This essay reports the screening of 64 SRAP primer combinations on 3 or 4 samples from every population with the intent of selecting the most reliable ones for subsequent analysis. PCR amplification products were assessed on 2% agarose gel and a total number of 1473 DNA fragments were visualized by EtBr staining. We selected fourteen primer combinations for further research based on clarity, reproducibility of amplified bands and high rates of polymorphism. The most efficient primer combination was Me8/Em3 which generated 42 visible DNA fragments. Â

Adaptive Regulation of Endothelin Receptor Type‐A and Type‐B in Vascular Smooth Muscle Cells during Pregnancy in Rats

Normal pregnancy is associated with systemic vasodilation and decreased vascular contraction, partly due to increased release of endothelium-derived vasodilator substances. Endothelin-1 (ET-1) is an endothelium-derived vasoconstrictor acting via endothelin receptor type A (ETA R) and possibly type B (ETB R) in vascular smooth muscle cells (VSMCs), with additional vasodilator effects via endothelial ETB R. However, the role of ET-1 receptor subtypes in the regulation of vascular function during pregnancy is unclear. We investigated whether the decreased vascular contraction during pregnancy reflects changes in the expression/activity of ETAR and ETBR. Contraction was measured in single aortic VSMCs isolated from virgin, mid-pregnant (mid-Preg, day 12), and late-Preg (day 19) Sprague-Dawley rats, and the mRNA expression, protein amount, tissue and cellular distribution of ETAR and ETBR were examined using RT-PCR, Western blots, immunohistochemistry, and immunofluorescence. Phenylephrine (Phe, 10(-5) M), KCl (51 mM), and ET-1 (10(-6) M) caused VSMC contraction that was in late-Preg < mid-Preg and virgin rats. In VSMCs treated with ETB R antagonist BQ788, ET-1 caused significant contraction that was still in late-Preg < mid-Preg and virgin rats. In VSMCs treated with the ETAR antagonist BQ123, ET-1 caused a small contraction; and the ETBR agonists IRL-1620 and sarafotoxin 6c (S6c) caused similar contraction that was in late-Preg < mid-Preg and virgin rats. RT-PCR revealed similar ETAR, but greater ETBR mRNA expression in pregnant versus virgin rats. Western blots revealed similar ETAR, and greater protein amount of ETBR in endothelium-intact vessels, but reduced ETBR in endothelium-denuded vessels of pregnant versus virgin rats. Immunohistochemistry revealed prominent ETBR staining in the intima, but reduced ETAR and ETBR in the aortic media of pregnant rats. Immunofluorescence signal for ETAR and ETBR was less in VSMCs of pregnant versus virgin rats. The pregnancy-associated decrease in ETAR- and ETBR-mediated VSMC contraction appears to involve downregulation of ETAR and ETBR expression/activity in VSM, and may play a role in the adaptive vasodilation during pregnancy.

Identification of Causative Pathogens in Eyes with Bacterial Conjunctivitis by Bacterial Cell Count and Microbiota Analysis

To determine the causative pathogens in eyes with bacterial conjunctivitis. Evaluation of diagnostic test or technology. Thirteen eyes diagnosed clinically with bacterial conjunctivitis and 12 eyes with normal conjunctival sac were studied. The bacterial cell numbers were counted in the samples stained by ethidium bromide (EtBr). The microbiota was determined by the clone library method using polymerase chain reaction (PCR) amplification of the 16S ribosomal RNA (rRNA) gene with universal primers. In addition, examinations of smears and cultures of samples were performed. Bacterial cell numbers determined by the EtBr staining method and microbiota analysis based on 16S rRNA gene of samples from eyes with bacterial conjunctivitis. The bacterial cell numbers in the eyes with bacterial conjunctivitis were significantly higher than those in the normal conjunctival sacs. Ten of 13 samples from the eyes with bacterial conjunctivitis had positive PCR results. The remaining 3 samples and all 12 samples from the normal conjunctiva had negative PCR results. In 5 of the 10 PCR-positive samples, the predominant species accounted for 84.5% or more of each clone library. In the remaining 5 samples, the predominant and the second dominant species accounted for 27.4% to 56.3% and 19.0% to 26.8%, respectively, of each clone library. The number of detected species in the clone libraries was between 8 and 20 (average ± standard deviation, 7.5 ± 5.8). Bacteria were detected in 8 of the 10 bacterial conjunctivitis samples and in 5 of the 12 normal samples in the cultures. The number of species detected by cultures was 1 in the eyes with bacterial conjunctivitis and between 1 and 3 (mean ± standard deviation, 1.6 ± 0.9) in the normal conjunctiva. These results showed that the bacterial cell number in a sample is a good method of determining bacterial conjunctivitis. The microbiota analysis detected a diverse group of microbiota in the eyes with bacterial conjunctivitis and showed that the causative pathogens could be determined based on percentages of bacterial species in the clone libraries. The combination of bacterial cell count and microbiota analysis is a good method for identifying the causative pathogens in cases of monomicrobial and polymicrobial conjunctivitis.

Cytotoxic studies of latex of Euphorbia antiquorum in in vitro models

The isolation and chemical characterization of plant derived compounds and its possible use for human well being requires solid and lengthy research. One of the determinants in this complex evaluation concerns the toxic potential of the studied agent. Our objective was to study the cytotoxicity of the methanolic extract latex of Euphorbia antiquorum using in vitro models namely Saccharomyces cerevisiae cells, brine shrimp and chick embryo fibroblasts. Hence, we analyzed the viability of normal cells exposed to varying concentrations of the latex in S. cerevisiae. Cytotoxicity was also tested using brine shrimp assay and LC50 was calculated. The cell viability was assessed by MTT assay, SRB assay and neutral red assay using various concentrations of the latex. Our study was focused on the combined effect of etoposide, a standard chemotherapeutic drug and latex of E. antiquorum on normal cells namely chick embryo fibroblasts and apoptotic events were observed using DAPI, PI EtBr staining. Cytotoxicity assays using S. cerevisiae and Brine shrimps showed that the latex was safe at lower concentrations compared to higher dose. Latex effectively counteracted etoposide mediated cytotoxicity, implying that these extracts can be used to protect non-cancerous cells in the body against etoposide induced ill-effects during cancer treatment. Key words: Cytotoxicity, in vitro models, LC50, brineshrimp assay, Euphorbia antiquorum.

Poly(ADP-ribose) Polymerase-1 (PARP-1) Contributes to the Barrier Function of a Vertebrate Chromatin Insulator

The prototypic chromatin insulator cHS4 has proven effective in reducing silencing chromosomal position effects in a variety of settings. Most of this barrier insulator activity has been mapped to a 250-bp core region, as well as to several proteins that bind this region. However, recent studies from our laboratory demonstrated that an extended 400-bp core region of the cHS4 element is necessary to achieve full barrier insulator activity when used as a single copy in the context of recombinant gammaretroviral and lentiviral vectors. In this study, electrophoretic gel mobility shift assays revealed specific DNA-protein binding activities associated with the distal portion of this extended core region. Affinity purification and tandem mass spectrometry studies led to the identification of one of these proteins as poly(ADP-ribose) polymerase-1 (PARP-1). The identity of this binding activity as PARP-1 was subsequently verified by a variety of biochemical studies in vitro and by chromatin immunoprecipitation studies in vivo. Functional studies with gammaretroviral reporter vectors in cell lines and primary mouse bone marrow progenitor cultures showed that cHS4 barrier activity was abrogated upon mutation of the putative PARP-1-binding site or upon treatment with a PARP inhibitor, respectively. The barrier activity of the cHS4 element was also found to be abrogated in studies using bone marrow from Parp1-null mice. Taken together, this study demonstrates that binding of PARP-1 plays a key functional role in the barrier activity of the extended cHS4 insulator core element.

Quantification of Plasmid DNA in pCA-HA/poly-L-lysine Complex

This report describes the comparison of four pDNA quantitative methods including UV/Visible spectro-photometry, agarose gel electrophoresis, EtBr staining fluoro-photometry and HPLCSEC method. Finally, the HPLC-SEC method was used to evaluate the interaction of plasmid DNA (pCA-HA) and poly-L-lysine (PLL). In the pCA-HA concentrations ranged form 3.125 to 50 μg/mL, the standard curve of pCA-HA has good linearity, accuracy (CV%＜3%) and precision (Error%＜4%) by using UV/Visible spectro-photometry. But the sensitivity is not enough to evaluate less than 3 μg/mL of pDNA. The intensity of fluorescene emission of EtBr stained pCA-HA is not dose dependent by using EtBr staining fluoro-photometry. The agarose gel electrophoresis had a high sensitivity (ng/mL level), but the accuracy (CV%＞15%) and precision (Error%＞15%) were not good in the range of 0.048~0.760 μg/mL pCA-HA. The standard curve of pCA-HA had good linearity, accuracy (CV%＜3%) and precision (Error%＜5%) in the pCA-HA concentration ranges from 0.4 to 1.2 μg/mL by using the HPLC-SEC method. PLL, a positive charged peptide, was used to condense DNA and enhance the transfection of DNA in cell. We used the HPLC-SEC method to evaluate the interaction of pDNA and PLL. When the charge of pCA-HA and PLL were almost the same, the peak of pDNA disappeared from the HPLC chromatogram. It means that the charge ratio of pCA-HA/PLL is close to 1 in the complex.

Expression and prognostic relevance of endothelin-B receptor in vulvar cancer

Overexpression of endothelin (ET)-1 and its receptors, ETAR and ETBR, commonly referred to as the 'ET-axis', has been demonstrated to play a role in cancer progression for various human tumours. Based on these results we propose a similar role of the expression of the ET-axis in vulvar cancer. Expression of the ET-axis was investigated immunohistochemically using tissue microarrays with tumour samples of 68 vulvar cancer patients. Samples were obtained from patients undergoing local excision or radical vulvectomy. ET-1 expression of tumour cells correlated highly significantly with early stages of vulvar cancer (p=0.004), whereas neither ETAR nor ETBR expression showed any association with TNM stages. High staining levels of ETBR in the tumour tissue were significantly related to tumour progression (p=0.01) and early metastases (p=0.09); low ETBR staining intensity correlated with longer relapse-free survival (p=0.019). In patients with ETBR overexpressing low-stage tumours (pT1-2) we observed a significantly reduced overall survival and disease-free survival (p=0.036 and 0.021, respectively). ETAR expression and ETBR expression were significantly correlative (p=0.018). Accordingly, co-expression of both receptors was related to tumour progression (p=0.022) and an increased risk for local recurrence (p=0.005). These results suggest that, in addition to established histological and clinical prognostic factors, analysis of ET-receptor and, in particular, of ETBR expression by means of simple immunohistochemical analysis might improve prediction of the prognosis for patients with vulvar squamous cell carcinoma.

Application of RNase in the purification of RNA-binding proteins

Application of RNase in the purification of RNA-binding proteins

Nicotiana tabacum Osmotic Stress-activated Kinase Is Regulated by Phosphorylation on Ser-154 and Ser-158 in the Kinase Activation Loop

NtOSAK (Nicotiana tabacum osmotic stress-activated protein kinase), a member of the SnRK2 subfamily, is activated rapidly in response to hyperosmotic stress. Our previous results as well as data presented by others indicate that phosphorylation is involved in activation of SnRK2 kinases. Here, we have mapped the regulatory phosphorylation sites of NtOSAK by mass spectrometry with collision-induced peptide fragmentation. We show that active NtOSAK, isolated from NaCl-treated tobacco BY-2 cells, is phosphorylated on Ser-154 and Ser-158 in the kinase activation loop. Prediction of the NtOSAK three-dimensional structure indicates that phosphorylation of Ser-154 and Ser-158 triggers changes in enzyme conformation resulting in its activation. The involvement of Ser-154 and Ser-158 phosphorylation in regulation of NtOSAK activity was confirmed by site-directed mutagenesis of NtOSAK expressed in bacteria and in maize protoplasts. Our data reveal that phosphorylation of Ser-158 is essential for NtOSAK activation, whereas phosphorylation of Ser-154 most probably facilitates Ser-158 phosphorylation. The time course of NtOSAK phosphorylation on Ser-154 and Ser-158 in BY-2 cells subjected to osmotic stress correlates with NtOSAK activity, indicating that NtOSAK is regulated by reversible phosphorylation of these residues in vivo. Importantly, Ser-154 and Ser-158 are conserved in all SnRK2 subfamily members, suggesting that phosphorylation at these sites may be a general mechanism for SnRK2 activation.

Asf1 Is Required for Viability and Chromatin Assembly during DNA Replication in Vertebrate Cells

Asf1 (anti-silencing function 1), a well conserved protein from yeast to humans, acts as a histone chaperone and is predicted to participate in a variety of chromatin-mediated cellular processes. To investigate the physiological role of vertebrate Asf1 in vivo, we generated a conditional Asf1-deficient mutant from chicken DT40 cells. Induction of Asf1 depletion resulted in the accumulation of cells in S phase with decreased DNA replication and increased mitotic aberrancy forming multipolar spindles, leading to cell death. In addition, nascent chromatin in Asf1-depleted cells showed increased nuclease sensitivity, indicating impaired nucleosome assembly during DNA replication. Complementation analyses revealed that the functional domain of Asf1 for cell viability was confined to the N-terminal core domain (amino acids 1-155) that is a binding platform for histones H3/H4, CAF-1p60, and HIRA, whereas Asf1 mutant proteins, abolishing binding abilities with both p60 and HIRA, exhibit no effect on viability. These results together indicate that the vertebrate Asf1 plays a crucial role in replication-coupled chromatin assembly, cell cycle progression, and cellular viability and provide a clue of a possible role in a CAF-1- and HIRA-independent chromatin-modulating process for cell proliferation.

Substrate Preferences of the EZH2 Histone Methyltransferase Complex

Histone methylation plays an important role in chromatin dynamics and gene expression. Methylation of histone H3-lysine 27 by the EZH2 complex has been linked to the silencing of homeotic genes and the inactivation of the X chromosome. Here we report a characterization of the substrate preferences of the enzyme complex using a reconstituted chromatin and enzyme system. We found that the linker histone H1, when incorporated into nucleosomes, stimulates the enzymatic activity toward histone H3. This stimulatory activity may be explained by protein-protein interactions between H1 and components of the EZH2 complex. In addition, we found that the EZH2 complex exhibits a dramatic preference for dinucleosomes when compared with mononucleosomes and that the stimulation of H3 methylation by H1 requires dinucleosomes or oligonucleosome substrates. Furthermore, in contrast with a recent study suggesting that Embryonic Ectoderm Development EED isoforms may affect substrate specificity, we found that EZH2 complexes reconstituted with different EED isoforms exhibit similar substrate preference and specificity. Our work supports the hypothesis that linker histone H1 and chromatin structure are important factors in determining the substrate preference of the EZH2 histone methyltransferase complex.

職場における微生物のリスク評価のためのバイオエアロゾル捕集方法および検出方法

Bioaerosols including bacteria and fungi have been almost unrecognized as pollutants of work environments in Japan. The combination of filter sampling and DNA staining by ethidium bromide (EtBr) was examined for the detection and evaluation of total numbers of bioaerosols, including viable and dead microorganisms, for risk assessment in work environments. With direct counting of microorganisms by EtBr concentrations of total cells were obtained in a shorter time than plate culture, the traditional method for detection of microorganisms. Total cell concentrations (cells/m3) were about 100 times greater than colonized cell concentrations (CFU/m3) in all samples. In some microscopic fields, macro conidia produced from some kinds of fungi were observed, but they were not detected by plate culture. Airborne bacterial 16S rDNA amplified by PCR were determined for their base sequences by DNA sequence analysis and classified by sequence-based homologies. Base sequences from 2 samples each contained 6 common groups of phylum. The combination of filter sampling and direct counting by EtBr staining was shown to be a better method for detecting and evaluating total cell concentrations in the risk assessment of sick building syndrome and allergy.

Regulation of KiSS-1 Metastasis Suppressor Gene Expression in Breast Cancer Cells by Direct Interaction of Transcription Factors Activator Protein-2α and Specificity Protein-1

KiSS-1 has been shown to function as a tumor metastasis suppressor gene and reduce the number of metastases in different cancers. The expression of KiSS-1 or KiSS1, like other tumor suppressor, is commonly reduced or completely ablated in a variety of cancers via an unknown mechanism. Here we show that the loss of KiSS-1 expression in highly metastatic breast cancer cell lines correlates directly with the expression levels of two transcription factors, activator protein-2alpha (AP-2alpha) and specificity protein 1 (Sp1), which synergistically activate the transcriptional regulation of KiSS-1 in breast cancer cells. Although the KiSS-1 promoter contains multiple AP-2alpha binding elements, AP-2alpha-mediated regulation occurs indirectly through Sp1 sites, as determined by deletion and mutation analysis. Overexpression of AP-2alpha into highly metastatic breast cell lines did not alter KiSS-1 promoter-driven luciferase gene activity. However, co-transfection of AP-2alpha wild-type or the dominant negative form of AP-2 lacking its C-terminal DNA-binding domain, AP-2B, together with Sp1, increased KiSS-1 promoter activity dramatically, suggesting that AP-2alpha regulation of KiSS-1 transcription does not require direct binding to the KiSS-1 promoter. Furthermore, we demonstrated that AP-2alpha directly interacted with Sp1 to form transcription complexes at two tandem Sp1-binding sites of the promoter to activate KiSS-1 transcription. Together, our results indicate that AP-2alpha and Sp1 are strong transcriptional regulators of KiSS-1 and that loss or decreased expression of AP-2alpha in breast cancer may account for the loss of tumor metastasis suppressor KiSS-1 expression and thus increased cancer metastasis.