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Öğe Mitochondrial miRNAs and fibromyalgia: new biomarker candidates(Springer Science and Business Media B.V., 2025) Kavak, Deniz Evrim; Dilek, Banu; Rasulova, Khayala; Pehlivan, Melek; Kızıldağ, Sefantroduction / objective: Fibromyalgia syndrome (FMS), affecting 3–10% of the population, presents a challenge due to its complex symptomatology. Mitochondrial miRNAs (mitomiRs) are highlighted for their significant role in metabolic disorders. This study aimed to assess demographic data in Primer FMS patients and explore potential targets through mitomiR profiling. Methods: In our study, we examined 17 FMS patients and 18 controls, chosen based on specific criteria. Mitochondria were isolated from PBMCs in patient/control blood samples using the MACS method. Mitochondrial purity was verified through RT-qPCR and Western Blot. Following this, we extracted microRNAs and analyzed the levels of 3 mitochondrial miRNAs linked to oxidative stress (mitomiR-145-5p, mitomiR-23a-3p, mitomiR-223-3p) using RT-qPCR. Results: It was found that pain (P < 0.0001), fatigue (P = 0.0005), sleep quality (P < 0.0001), and depression (P < 0.0001) scores were significantly different in the FMS patient group compared to the control group. But the average BMI values have no difference compared to the control group (p = 0.7473). For the first time, a significant increase in mitomiR-145-5p was observed in the PBMCs of FMS patients compared to the control group (p = 0.0010). There was no significant difference observed in the gene expression levels of mitomiR-223-3p (p = 0.1623) and mitomiR-23a-3p (p = 0.4897). Conclusion: We demonstrated that mitomiR-145-5p plays a significant role in the progression of FMS pathology. Our study offers new insights, suggesting that mitochondrial miRNAs may have roles in FMS patients, which has not been previously investigated in the literature, thus providing a fresh perspective on the condition.Öğe Editorial: Acute leukemias: molecular characterization, leukemia-initiating cells, and influence of the microenvironment, volume II(Frontiers, 06.01.2025) Varışli, Lokman; Dancik, Garrett M.; Copland, John A.; Vlahopoulos, Spiros A.Acute leukemia is a wide group of hematologic malignancies that arise from leukemiainitiating cells (LICs), also known as leukemic stem cells (LSCs), which originate from transformed hematopoietic stem cells (HSCs) in the bone marrow. Leukemic cells accumulate various genetic and epigenetic defects, both inherited from the LICs they originate from and acquired later. Genetic defects in leukemic cells determine their biological behavior and, as expected, affect the prognosis of the disease and its response to treatment. Therefore, molecular characterization of the disease is important for all stages of the disease, such as predicting prognosis, determining the treatment approach, and evaluating the possibility of recurrence. In this context, a better understanding of the molecular mechanisms of acute leukemia will enable the emergence of simpler and more effective treatment approaches and increase the rate of treated patients.Öğe Investigating the biology of microRNA links to ALDH1A1 reveals candidates for preclinical testing in acute myeloid leukemia(Spandidos Publications, 30.10.2024) Vlahopoulos, Spiros A.; Varışli, Lokman; Zoumpourlis, Panagiotis; Spandidos, Demetrios A.; Zoumpourlis, VassilisAldehyde dehydrogenase 1 family member A1 (ALDH1A1) is a member of the aldehyde dehydrogenase gene subfamily that encode enzymes with the ability to oxidize retinaldehyde. It was recently shown that high ALDH1A1 RNA abundance correlates with a poor prognosis in acute myeloid leukemia (AML). AML is a hematopoietic malignancy associated with high morbidity and mortality rates. Although there are a number of agents that inhibit ALDH activity, it would be crucial to develop methodologies for adjustable genetic interference, which would permit interventions on several oncogenic pathways in parallel. Intervention in multiple oncogenic pathways is theoretically possible with microRNAs (miRNAs or miRs), a class of small non‑coding RNAs that have emerged as key regulators of gene expression in AML. A number of miRNAs have shown the ability to interfere with ALDH1A1 gene expression directly in solid tumor cells, and these miRNAs can be evaluated in AML model systems. There are indications that a few of these miRNAs actually do have an association with AML disease course, rendering them a promising target for genetic intervention in AML cells.Öğe The nephroprotective effect of Quercetin in Cyclophosphamide-induced renal toxicity might be associated with MAPK/ERK and NF-κB signal modulation activity(Taylor and Francis Ltd., 2024) Şeker, Uğur; Kavak, Deniz Evrim; Dokumacı, Fatma Zehra; Kızıldağ, Sefa; Kandemir, Sevgi İrtegünThe present study aimed to examine the protective effect of quercetin (QUE) on cyclophosphamide (CTX)-induced nephrotoxicity. For that purpose, 24 mice were divided into four groups (Control, QUE, CTX, and CTX + QUE). The CTX and CTX + QUE groups received 200 mg/kg of cyclophosphamide on the 1st and 7th days. The QUE and CTX + QUE groups were treated with 50 mg/kg of quercetin daily for 14 days. At the end of the experiment, the animals were sacrificed, and kidney samples were analyzed. The results indicated that CTX leads to severe morphological degenerations and disruption in renal function. Serum BUN, Creatinine, Uric acid, tissue Bax, Caspase 3, TNF-α and IL-1β expression levels were upregulated in the CTX group compared to Control and QUE groups (p < 0.05). Although MAPK/ERK phosphorylation level is not affected in CTX group, there was a significant increase in CTX + QUE group (p < 0.05), but the NF-κB was significantly suppressed in this group (p < 0.01). The RT-qPCR results showed that the cyt-c and the Bax/Bcl-2 ratio mRNA expression folds were upregulated in the CTX group (p < 0.01), which was downregulated in the CTX + QUE group. However, there was a significant difference in the CTX + QUE group compared to the Control and QUE groups (p < 0.01). The findings showed that administering quercetin along with cyclophosphamide alleviated renal injury by regulating apoptotic and inflammatory expression. Moreover, the administration of quercetin and cyclophosphamide could synergistically improve renal function test results, and activate cellular responses, which upmodulate MAPK/ERK phosphorylation and suppression of NF-κB.Öğe Thermophilic and halophilic microorganisms isolated from extreme environments of Turkey, with potential biotechnological applications(Springer-Verlag Singapore Pte Ltd, 2018) Güven, Kemal; Bekler, Fatma Matpan; Güven, Reyhan GülTurkey has a great number of different ecological areas, owning over 200 hot water resources and various hypersaline environments with a broad microbial diversity and opportunities for newly isolated microorganisms from extreme environments for many industrial applications. A variety of thermophilic and halophilic microorganisms in different regions of Turkey have been isolated and identified. The thermophilic bacterial members studied were Anoxybacillus, Geobacillus, Bacillus, Brevibacillus, and Aeribacillus belonging to the Bacillaceae family and the other thermophiles such as Thermus and Thermomonas, whereas the isolated halophilic microorganisms were mainly found to be members of the archaeal family Halobacteriaceae or grouped into bacterial phylum Bacteroidetes. In summary, the present study reviews on (1) isolating and identifying thermophiles and halophiles single or as community from various extreme habitats in Turkey based on conventional (morphological, physiological and biochemical tests) and/or molecular methods, (2) screening these extremophiles for industrially important enzymes, (3) studying other novel products and their use in other areas of biotechnology, and finally (4) discussing about the development strategies and the future perspectives on poorly studied extremophilic microorganisms in the country to fulfill future biotechnological and industrial demands.Öğe The effects of amino acids on production and transport of α-amylase through bacterial membranes(Wiley-VCH Verlag, 2000) Agüloǧlu, Sema; Ensari, N. Yavuz; Uyar, Fikret; Otludil, Birol; 0000-0002-3809-5987Bacillus subtilis was grown in media containing various amino acids. The effects of these aminoacids on the production of secreted alpha-amylase and membrane-bound alpha-amylase were investigated. Their effects on the transport of alpha-amylase through membranes were also determined. The synthesis rate of alpha-amylase isolated from bacterial membranes was stimulated by growth in media separately containing Ala and Arg, all other amino acids being inhibitory. Cys, Arg and Leu increased the transport of alpha-amylase through the membrane, while Ala, Asp and Ser inhibited it. Secreted alpha-amylase activity was appreciably stimulated by Ala, Arg, Gin, Gly, Leu, Phe, Pro, and especially Cys while it was repressed by Asp, Asn, Glu, Lys, Met, Ser, Thr and Trp.Öğe The toxicity of dithiocarbamate fungicides to soil nematodes, assessed using a stress-inducible transgenic strain of Caenorhabditis elegans(John Wiley and Sons Inc., 1999) Güven, Kemal; Power, Rowena S.; Avramides, Sophia; Allender, Rebecca; de Pomerai, David I.; 0000-0002-0181-3746The dithiocarbamate fungicides maneb and mancozeb induce a short-term stress response in a transgenic Caenorhabditis elegans strain (PC72) carrying a reporter lacZ gene under the control of a homologous heat shock (hsp16) promoter. This response can be readily monitored as induced beta-galactosidase activity, either by in situ staining or by a quantitative fluorometric enzyme assay. Particularly strong responses are induced by mancozeb (three- to fivefold above controls at 500 pg mL(-1)), causing acute toxicity at concentrations comparable to those recommended for field application (2 mg mL(-1)). Although much of this fungicide is adsorbed by soil, sufficient (ca. 6%) enters the soil water compartment to cause mild stress in the transgenic worm assay. Among possible metabolites from mancozeb breakdown, neither Mn2+ nor ethylenethiourea (ETU) is particularly toxic even at 10% of the optimum mancozeb dosage. Stress responses to a range of other pesticides are also reported, and in several cases it is clear that a nontarget soil species there, transgenic C. elegans) may be sensitive to low-level contamination. (C) 1999 John Wiley & Sons, Inc.Öğe Toxicity of the dithiocarbamate fungicide mancozeb to the nontarget soil nematode, Caenorhabditis elegans(Wiley, 2001) Easton, Anna; Güven, Kemal; de Pomerai, David I.; 0000-0002-0181-3746We have previously shown that the dithiocarbamate fungicide, Mancozeb, strongly induces lacZ reporter expression from an endogenous heat-shock promoter (hsp16) in the PC72 transgenic strain of the nematode Caenorhabditis elegans. Such evidence of organismal stress, in a nontarget species at subapplication concentrations, was much less apparent for the related fungicide, Maneb, which only weakly induced reporter expression. We now show that reporter induction by Mancozeb is marginal (<60%) after a few hours' exposure, but increases substantially (to almost 10-fold) after overnight exposure. In conjunction with our previous results using intermediate exposure periods, this suggests that the factor limiting reporter responses is likely to be a slow rate of uptake and/or metabolism of the fungicide. We confirm that a potentially toxic metabolite of dithiocarbamate fungicides, namely ethylenethiourea (ETU), has minimal toxicity toward C. elegans, even after prolonged exposure at high concentrations. We demonstrate that exposure to Mancozeb (but not ETU) significantly inhibits larval growth in C. elegans, although this parameter is not markedly more sensitive than reporter induction as a toxicological endpoint. Finally, we have used two-dimensional electrophoresis to show that high concentrations of both Maneb and Mancozeb drastically simplify the protein spot profile compared with controls. However, only in the latter case is there evidence of novel proteins being induced. Both fungicides appear toxic to C. elegans, but only Mancozeb induces a strong heat-shock response. (C) 2001 John Wiley & Sons, Inc.Öğe Investigation of the occurrence of silene fuscata in Anatolia based on molecular analysis(ABADER (Adıyaman Bilimsel Arastırmalar Dernegi), 2023) Toprak, ZeynepSilene fuscata is an annual species distributed to a wide geography including Eastern Mediterranean, Northern Africa, and Southern Europe. The native range of this species is known as the Mediterranean Region. Presence of S. fuscata in Anatolia is reported by several comprehensive botanical literatures; however, the actual situation has never been investigated thoroughly. This study focuses on the occurrence of S. fuscata in Anatolia. In order to determine the existence of this species in the aforementioned area, nuclear and chloroplast-DNA sequence data from a wide range of Silene samples were analyzed. DNA sequence analyses and other available evidence display no support for the presence of S. fuscata in Anatolia.Öğe Epithelial–mesenchymal transition in acute leukemias(MDPI, 2024) Varışli, Lokman; Vlahopoulos, SpirosEpithelial–mesenchymal transition (EMT) is a metabolic process that confers phenotypic flexibility to cells and the ability to adapt to new functions. This transition is critical during embryogenesis and is required for the differentiation of many tissues and organs. EMT can also be induced in advanced-stage cancers, leading to further malignant behavior and chemotherapy resistance, resulting in an unfavorable prognosis for patients. Although EMT was long considered and studied only in solid tumors, it has been shown to be involved in the pathogenesis of hematological malignancies, including acute leukemias. Indeed, there is increasing evidence that EMT promotes the progression of acute leukemias, leading to the emergence of a more aggressive phenotype of the disease, and also causes chemotherapy resistance. The current literature suggests that the levels and activities of EMT inducers and markers can be used to predict prognosis, and that targeting EMT in addition to conventional therapies may increase treatment success in acute leukemias.Öğe Characterization of a thermally stable ?-galactosidase produced by thermophilic anoxybacillus sp. AH1(Bingöl Üniversitesi Fen Bilimleri Enstitüsü, 2021) Acer, Ömer; Bekler, Fatma MatpanThermostable β-galactosidases from thermophilic bacteria have attracted increasing interest to have various advantages in industrial and biotechnological applications. In this study, a highly thermally stable β-galactosidase produced by Anoxybacillus sp. AH1 was purified and characterized. The highest enzyme production was achieved after the bacterium was incubated for 24 hours. The enzyme was purified by precipitation with ammonium sulphate dialysis, gel filtration chromatography using Sephadex G-75. After the purification steps, β-galactosidase was found to be purified 10.2-fold and a yield of 13.9%. The molecular mass of the β-galactosidase was estimated to be 75 kDa by SDS-PAGE. The purified enzyme was highly stable and retained at 71% of the original activity at 60 °C and 53% at 70 oC within 120 minutes. The Km and Vmax values of purified β-galactosidase were calculated as 1.249 mM and 0.5 μmol minutes-1 , respectively. Ca2+, Zn2+, and Mg2+ significantly activated β-galactosidase activity, whereas enzyme activity was inhibited significantly by Cu+2 as well as by the metal ion chelators1,10- phenanthroline (phen) and ethylenediaminetetraacetic acid (EDTA). The Purified β-galactosidase activity was increased by PMSF (phenylmethylsulfonyl fluoride), PCMB (pchloromercuribenzoic acid), DTT (dithiothreitol), and β-ME (β-mercaptoethanol) at 2 mM, but inhibited completely by NEM (N-ethylmaleimide) at 1 mM.Öğe OGG1 as an epigenetic reader affects NF?B: What this means for cancer(MDPI, 2024) Vlahopoulos, Spiros; Pan, Lang; Varışli, Lokman; Dancik, Garrett M.; Karantanos, Theodoros; Boldogh, Istvan8-oxoguanine glycosylase 1 (OGG1), which was initially identified as the enzyme that catalyzes the first step in the DNA base excision repair pathway, is now also recognized as a modulator of gene expression. What is important for cancer is that OGG1 acts as a modulator of NFκB-driven gene expression. Specifically, oxidant stress in the cell transiently halts enzymatic activity of substrate-bound OGG1. The stalled OGG1 facilitates DNA binding of transactivators, such as NFκB to their cognate sites, enabling the expression of cytokines and chemokines, with ensuing recruitment of inflammatory cells. Recently, we highlighted chief aspects of OGG1 involvement in regulation of gene expression, which hold significance in lung cancer development. However, OGG1 has also been implicated in the molecular underpinning of acute myeloid leukemia. This review analyzes and discusses how these cells adapt through redox-modulated intricate connections, via interaction of OGG1 with NFκB, which provides malignant cells with alternative molecular pathways to transform their microenvironment, enabling adjustment, promoting cell proliferation, metastasis, and evading killing by therapeutic agents.Öğe Critical roles of SRC-3 in the development and progression of breast cancer, rendering it a prospective clinical target(MDPI, 31.10.2023) Varışli, Lokman; Dancik, Garrett M.; Tolan, Veysel; Vlahopoulos, SpirosBreast cancer (BCa) is the most frequently diagnosed malignant tumor in women and is also one of the leading causes of cancer-related death. Most breast tumors are hormone-dependent and estrogen signaling plays a critical role in promoting the survival and malignant behaviors of these cells. Estrogen signaling involves ligand-activated cytoplasmic estrogen receptors that translocate to the nucleus with various co-regulators, such as steroid receptor co-activator (SRC) family members, and bind to the promoters of target genes and regulate their expression. SRC-3 is a member of this family that interacts with, and enhances, the transcriptional activity of the ligand activated estrogen receptor. Although SRC-3 has important roles in normal homeostasis and developmental processes, it has been shown to be amplified and overexpressed in breast cancer and to promote malignancy. The malignancy-promoting potential of SRC-3 is diverse and involves both promoting malignant behavior of tumor cells and creating a tumor microenvironment that has an immunosuppressive phenotype. SRC-3 also inhibits the recruitment of tumor-infiltrating lymphocytes with effector function and promotes stemness. Furthermore, SRC-3 is also involved in the development of resistance to hormone therapy and immunotherapy during breast cancer treatment. The versatility of SRC-3 in promoting breast cancer malignancy in this way makes it a good target, and methodical targeting of SRC-3 probably will be important for the success of breast cancer treatment.Öğe Isolation and characterization of alkane hydrocarbons-degrading Delftia tsuruhatensis strain D9 from petroleum-contaminated soils(Field Crops Central Research Institute, 2022) Eren, Ayşe; Güven, KemalA bacterial strain from petroleum-contaminated soil in south-eastern Turkey was isolated and characterized to determine the potential of alkane hydrocarbon biodegradation. Phenotypic characteristics and the sequence analysis of the 16S rRNA gene revealed that the strain D9 is a member of the Delfitia genus and most similar to Delftia tsuruhatensis (100%). The optimum pH and temperature values for the growth of D. tsuruhatensis strain D9 were found to be 9.0-10.0 and 35°C, respectively. The strain was found to grow in some single, medium and long-chain hydrocarbons such as decane, hexadecane, and squalene, tested by short-time incubation in basal medium (BM) in the presence of 1% hydrocarbon concentrations under optimum conditions. After incubation for 3 days, 65% of the single hydrocarbon hexadecane was degraded by the D. tsuruhatensis strain D9, revealed by GC-MS analysis. The biodegradation of petroleum hydrocarbons by D. tsuruhatensis strain D9 isolated and characterized in the present study shows that it can be a good candidate in the bioremediation process.Öğe Aldehyde dehydrogenase genes as prospective actionable targets in acute myeloid leukemia(MDPI, 2023) Dancik, Garrett M.; Varışli, Lokman; Tolan, Veysel; Vlahopoulos, SpirosIt has been previously shown that the aldehyde dehydrogenase (ALDH) family member ALDH1A1 has a significant association with acute myeloid leukemia (AML) patient risk group classification and that AML cells lacking ALDH1A1 expression can be readily killed via chemotherapy. In the past, however, a redundancy between the activities of subgroup members of the ALDH family has hampered the search for conclusive evidence to address the role of specific ALDH genes. Here, we describe the bioinformatics evaluation of all nineteen member genes of the ALDH family as prospective actionable targets for the development of methods aimed to improve AML treatment. We implicate ALDH1A1 in the development of recurrent AML, and we show that from the nineteen members of the ALDH family, ALDH1A1 and ALDH2 have the strongest association with AML patient risk group classification. Furthermore, we discover that the sum of the expression values for RNA from the genes, ALDH1A1 and ALDH2, has a stronger association with AML patient risk group classification and survival than either one gene alone does. In conclusion, we identify ALDH1A1 and ALDH2 as prospective actionable targets for the treatment of AML in high-risk patients. Substances that inhibit both enzymatic activities constitute potentially effective pharmaceutics.Öğe Antimicrobial and antioxidant effect of Ficaria verna Huds.(Yüzüncü Yıl Üniversitesi Ziraat Fakültesi, 2021) İnci, Şule; Eren, Ayşe; Kırbağ, Sevda; Özkan, Ahmet İsmailFicaria verna Huds. is a plant belonging to the Ranunculaceae family, known as mole grass and celandine among the people. It is known to have antiinflammatory and anti-haemorrhagic pharmaceutical effects. In this study, it was aimed to determine the antimicrobial effect of different concentrations of F. verna extracts obtained from methanol, ethanol and chloroform and the antioxidant activity of different concentrations of the extract obtained from methanol. In the results obtained, the best antimicrobial effect (17-20 mm) against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Bacillus megaterium, Salmonella thypii and Candida albicans was determined in the methanol extract of F. verna at a concentration of 1000 µg. It was observed that the scavenging effect of the DPPH radical of F. verna increased depending on increasing concentrations.Öğe The Molecular context of oxidant stress response in cancer establishes ALDH1A1 as a critical target: What this means for acute myeloid leukemia(MDPI, 2023) Dancik, Garrett M.; Varışli, Lokman; Vlahopoulos, Spiros A.The protein family of aldehyde dehydrogenases (ALDH) encompasses nineteen members. The ALDH1 subfamily consists of enzymes with similar activity, having the capacity to neutralize lipid peroxidation products and to generate retinoic acid; however, only ALDH1A1 emerges as a significant risk factor in acute myeloid leukemia. Not only is the gene ALDH1A1 on average significantly overexpressed in the poor prognosis group at the RNA level, but its protein product, ALDH1A1 protects acute myeloid leukemia cells from lipid peroxidation byproducts. This capacity to protect cells can be ascribed to the stability of the enzyme under conditions of oxidant stress. The capacity to protect cells is evident both in vitro, as well as in mouse xenografts of those cells, shielding cells effectively from a number of potent antineoplastic agents. However, the role of ALDH1A1 in acute myeloid leukemia has been unclear in the past due to evidence that normal cells often have higher aldehyde dehydrogenase activity than leukemic cells. This being true, ALDH1A1 RNA expression is significantly associated with poor prognosis. It is hence imperative that ALDH1A1 is methodically targeted, particularly for the acute myeloid leukemia patients of the poor prognosis risk group that overexpress ALDH1A1 RNA.Öğe Editorial: Acute leukemias: molecular characterization, leukemia-initiating cells, and influence of the microenvironment(Frontiers, 2023) Dancik, Garrett M.; Varışli, Lokman; Voutsas, Ioannis F.; Vlahopoulos, SpirosAcute leukemias remain a challenge, in spite of improvements in diagnosis and treatment. Fully establishing the depth and extent of the relative impact of the molecular mechanisms of disease progression and the pathways to recurrent disease will require decades of research, until our comprehension enables the routine development of simple and effective cures. This special issue was aimed to address progress in the characterization of the molecular basis of acute leukemias and to explore potential links with disease course.Öğe Essential oil compositions and antimicrobial activities of Thymbra spicata L. var. spicata L., Lavandula X Intermedia Emeric ex Loisel., Satureja macrantha C. A. MEYER and Rosmarinus officinalis L.(Inst Tecnologia Parana, 2022) Karakaş, Özgür; Bekler, Fatma MatpanMedicinal and aromatic plants have been widely using in folk medicine as antimicrobial, anti-inflammatory and antinociceptive agents. The aim of this study was to determine essential oil composition and antimicrobial activity of T. spicata, L. X Intermedia, S. macrantha and R. officinalis. Essential oil components of these plants were obtained by water vapor distillation method using Neo-Clevenger apparatus. Essential oil components were determined by gas chromatography-mass spectroscopy (GC-MS). The main components of these plants are carvacrol (74.26 %) and gamma-terpinene (10.28%) in T. spicata, 1,8-cineol (32.48%), linalool (24.38%) and camphor (14.73%) in L. X Intermedia, p-cymene (56.70%), carvacrol (10.96 %) in S. macrantha and camphor (18.26 %), alpha-pinene (15.51%), 1,8-cineole (11.86%) and borneol (10.39%) in R. officinalis were determined. T. spicata and S. macrantha showed strong effects against three microorganisms. L. X lntermedia and R. officinalis showed strong activity against Candida albicans, while they had moderate effects against Staphylococcus aureus, Escherichia coli.Öğe HN1 is enriched in the S-phase, phosphorylated in mitosis, and contributes to Cyclin B1 degradation in prostate cancer cells(MDPI, 2023) Javed, Aadil; Özduman, Gülseren; Varışli, Lokman; Öztürk, Bilge Esin; Kormaz, Kemal SamiHN1 has previously been shown as overexpressed in various cancers. In Prostate cancer, it regulates AR signaling and centrosome-related functions. Previously, in two different studies, HN1 expression has been observed as inversely correlated with Cyclin B1. However, HN1 interacting partners and the role of HN1 interactions in cell cycle pathways have not been completely elucidated. Therefore, we used Prostate cancer cell lines again and utilized both transient and stable inducible overexpression systems to delineate the role of HN1 in the cell cycle. HN1 characterization was performed using treatments of kinase inhibitors, western blotting, flow cytometry, immunofluorescence, cellular fractionation, and immunoprecipitation approaches. Our findings suggest that HN1 overexpression before mitosis (post-G2), using both transient and stable expression systems, leads to S-phase accumulation and causes early mitotic exit after post-G2 overexpression. Mechanistically, HN1 interacted with Cyclin B1 and increased its degradation via ubiquitination through stabilized Cdh1, which is a co-factor of the APC/C complex. Stably HN1- expressing cells exhibited a reduced Cdt1 loading onto chromatin, demonstrating an exit from a G1 to S phenotype. We found HN1 and Cdh1 interaction as a new regulator of the Cyclin B1/CDK1 axis in mitotic regulation which can be explored further to dissect the roles of HN1 in the cell cycle.
