DigitalUM :: Browsing by Subject "Cell cycle"

Browsing by Subject "Cell cycle"

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Open Access
Antitumor activity of rosmarinic acid-loaded silk fibroin nanoparticles on HeLa and MCF-7 cells
(MDPI, 2021-09-18) Fuster, Marta G.; Carissimi, Gúzmán; García Montalbán, Mercedes; Víllora Cano, Gloria; Ingeniería Química
Rosmarinic acid (RA), one of the most important polyphenol-based antioxidants, has drawn increasing attention because of its remarkable bioactive properties, including anti-inflammatory, anticancer and antibacterial activities. The aim of this study was to synthesize and characterize RA-loaded silk fibroin nanoparticles (RA-SFNs) in terms of their physical–chemical features and composition, and to investigate their antitumor activity against human cervical carcinoma and breast cancer cell lines (HeLa and MCF-7). Compared with the free form, RA bioavailability was enhanced when the drug was adsorbed onto the surface of the silk fibroin nanoparticles (SFNs). The resulting particle diameter was 255 nm, with a polydispersity index of 0.187, and the Z-potential was −17 mV. The drug loading content of the RA-SFNs was 9.4 wt.%. Evaluation of the in vitro drug release of RA from RA-SFNs pointed to a rapid release in physiological conditions (50% of the total drug content was released in 0.5 h). Unloaded SFNs exhibited good biocompatibility, with no significant cytotoxicity observed during the first 48 h against HeLa and MCF-7 cancer cells. In contrast, cell death increased in a concentration-dependent manner after treatment with RA-SFNs, reaching an IC50 value of 1.568 and 1.377 mg/mL on HeLa and MCF-7, respectively. For both cell lines, the IC50 of free RA was higher. The cellular uptake of the nanoparticles studied was increased when RA was loaded on them. The cell cycle and apoptosis studies revealed that RA-SFNs inhibit cell proliferation and induce apoptosis on HeLa and MCF-7 cell lines. It is concluded, therefore, that the RA delivery platform based on SFNs improves the antitumor potential of RA in the case of the above cancers.
Open Access
Antitumor Activity of Rosmarinic Acid-Loaded Silk Fibroin Nanoparticles on HeLa and MCF-7 Cells
(MDPI, 2021-09-18) Fuster, M. G.; Carissimi, G.; Montalbán, M. G.; Víllora Cano, Gloria; Ingeniería Química; Facultad de Química
Rosmarinic acid (RA), one of the most important polyphenol-based antioxidants, has drawn increasing attention because of its remarkable bioactive properties, including anti-inflammatory, anticancer and antibacterial activities. The aim of this study was to synthesize and characterize RA-loaded silk fibroin nanoparticles (RA-SFNs) in terms of their physical–chemical features and composition, and to investigate their antitumor activity against human cervical carcinoma and breast cancer cell lines (HeLa and MCF-7). Compared with the free form, RA bioavailability was enhanced when the drug was adsorbed onto the surface of the silk fibroin nanoparticles (SFNs). The resulting particle diameter was 255 nm, with a polydispersity index of 0.187, and the Z-potential was 􀀀17 mV. The drug loading content of the RA-SFNs was 9.4 wt.%. Evaluation of the in vitro drug release of RA from RA-SFNs pointed to a rapid release in physiological conditions (50% of the total drug content was released in 0.5 h). Unloaded SFNs exhibited good biocompatibility, with no significant cytotoxicity observed during the first 48 h against HeLa and MCF-7 cancer cells. In contrast, cell death increased in a concentration-dependent manner after treatment with RA-SFNs, reaching an IC50 value of 1.568 and 1.377 mg/mL on HeLa and MCF-7, respectively. For both cell lines, the IC50 of free RA was higher. The cellular uptake of the nanoparticles studied was increased when RA was loaded on them. The cell cycle and apoptosis studies revealed that RA-SFNs inhibit cell proliferation and induce apoptosis on HeLa and MCF-7 cell lines. It is concluded, therefore, that the RA delivery platform based on SFNs improves the antitumor potential of RA in the case of the above cancers.
Open Access
Apoptotic effect of selenium mushroom extract from Qinba on multiple myeloma cells
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2023) Yang, Ge; Song, Ze; Wang, Rongli; Sun, Yanqin
Qinba selenium mushroom is a mushroom belonging to the Basidiomycetes family, which is believed to have anti- oxidant, anti-tumoral and antimutagenic activities. However, the efficacy of Qinba selenium mushroom against multiple myeloma has not been confirmed. The present study aimed to investigate the apoptotic effect of FA-2-b-β, the selenium mushroom extract from Qinba on multiple myeloma (MM) cells. The MM RPMI-8226 cells were treated with FA-2-b-β at different concentrations and time points. MM RPMI8226 cell proliferation and apoptosis were detected by the Cell Counting Kit-8 (CCK-8) assay and Annexin V/propidium iodide (PI) assay, RT-QPCR and western blotting analyses were performed to determine the proteins and pathways involved. The results of the present study demonstrated that FA-2-b-β has high antiproliferative activities and strong pro-apoptotic effects on MM RPMI-8226 cells, and its pharmacological effects on proliferation changes occurred in a dose- and time-dependent manner. In addition, we found that FA2-b-β was able to induce cell apoptosis and promote cell cycle arrest at G0/G1 phase. In summary, the results illustrate the involvement of FA-2-b-β in mediating G0/G1 cell cycle arrest and apoptosis in MM RPMI8226 cells, which suggested that FA-2-b-β might have therapeutic potential against multiple myeloma as an effective compound, and may provide useful information for the development of a novel therapeutic target in this area.
Open Access
Are synchronous and metachronous bilateral breast cancers different? An immunohistochemical analysis focused on cell cycle regulation
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Senkus, Elżbieta; Szade, Jolanta; Pieczyńska, Beata; Kunc, Michał; Pliszka, Agnieszka; Jassem, Jacek
Introduction. The biology and pathomechanisms of bilateral breast cancers is not fully understood. We compared the morphological and immunohistochemical characteristics of primary tumors in patients with synchronous (sBBC) and metachronous bilateral breast cancers (mBBC), with special focus on cell cycle regulation and its correlation with markers determining intrinsic phenotype. Methods. Immunohistochemical expression of p16Ink4A, p21(WAF1/CIP1) , p27Kip1, p53, cyclin A, cyclin B, cyclin D1, cyclin D3 and cyclin E was assessed in tissue microarrays containing primary breast tumor cores from 113 mBBC and 61 sBBC. Expression of these markers was correlated with tumor grade and expression of estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2) and Ki-67. Results. In univariate analysis, mBBC demonstrated higher expression of p16Ink4A (both cytoplasmic: p=0.002 and nuclear: p=0.014), cyclin A (p=0.024) and B (cytoplasmic; p=0.015). In multivariate analysis mBBC were associated with lower expression of p21: p=0.038 and higher cytoplasmic expression of cyclin B: p=0.019. Lower ER expression for all BBCs and mBBC, respectively, was associated with stronger p16 expression (cytoplasmic: both p<0.000001 and nuclear: p<0.000001, p=0.00002), p53: p<0.000001, p=0.000001, cyclin A: p=0.00002, p=0.00045, cyclin B (cytoplasmic: p=0.00037, 0.00015 and nuclear: both p=0.0004) and cyclin E: p=000003, p<0.000001, and weaker expression of p27: p=0.00003, p=0.0001 and cyclin D1: both p<0.000001; for sBBC some of these correlations were absent. Higher p27 score correlated with lower HER2 expression in sBBC: p=0.018, whereas higher HER2 expression was associated with higher p53: 0.024 and cyclin E: p=0.048 expression in all BBC and higher nuclear expression of cyclin B in sBBC: p=0.027. Higher Ki-67 expression was correlated with higher expression of p16 (cytoplasmic: p=0.000015, p=0.086, p=0.0002 and nuclear: p=0.000009, p=0.016, p=0.00003) in all subsets [all BBC, sBBC (nonsignificant for cytoplasmic score), mBBC, respectively], p21 (all BBC: p=0.05) and sBBC: p=0.017), p53 (all BBC: p=0.0003 and mBBC: p=0.0002), cyclin A: all p<0.000001, cyclin B (cytoplasmic: p<0.000001, p=0.004, p<0.000001, respectively and nuclear: p=0.0002, p=0.047, p=0.0026, respectively), cyclin D3 (all BBC: p=0.005 and mBBC: p=0.02) and cyclin E (all BBC: p<0.000001 and mBBC: p=0.000002), and lower expression of cyclin D1 (all BBC: p=0.046 and mBBC: p=0.035) and p27 (sBBC: p=0.048). Conclusion. Compared to sBBC, mBBC are characterized by lower expression of p21 and higher cytoplasmic expression of cyclin B, suggesting its more aggressive behavior. Correlations between cell-cycle regulation proteins and markers of breast cancer phenotype parallel those reported for unilateral breast cancer.
Open Access
CD26: An expanding role in immune regulation and cancer
(Murcia : F. Hernández, 2002) Dang, N.H.; Morimoto, C.
In this review, we highlight major aspects of the biology of CD26, a dipeptidyl peptidase IV (DPPIV)-containing surface glycoprotein with multiple functions. In particular, we discuss findings demonstrating that CD26/DPPIV has an essential role in immune regulation as a T cell activation molecule and a regulator of chemokine function. We also review recent studies that identify key cellular molecules that physically associate with CD26 and the potential consequences of their interaction, including those with clinically-related implications. Furthermore, we present work suggesting a role for CD26 in the pathogenesis and behavior of selected human cancers, both solid tumors and hematological malignancies. We present recent studies that investigate the potential role of CD26 as a molecular target for novel treatment modalities for T cell lymphoid malignancies and possibly other hematological malignancies, with work involving the use of anti-CD26 monoclonal antibody, CD26-transfected cells as well as soluble CD26 molecules.
Open Access
Cell cycle alterations and lung cancer
(Murcia : F. Hernández, 2006) Vincenzi, B.; Schiavon, G.; Silletta, M.; Santini, D.; Perrone, G.M.; Di Marino, M.; Angeletti, S.; Baldi, A.; Tonini, G.
It is now widely accepted that human carcinogenesis is a multi-step process and phenotypic changes during cancer progression reflect the sequential accumulation of genetic alterations in cells. The recent progress of scientific research has notably increased knowledge about biological events involved in lung cancer pathogenesis and progression, thanks to the use of molecular biology and immunohistochemistry techniques. Lots of the genetic alteration found in small cells lung cancer (SCLC) and in not small cells lung cancer (NSCLC) concern the expression of cell cycle genes, actually recognized as onco-suppressor genes and the lack of equilibrium between oncogenes and oncosuppressor genes. The present review of literature widely describes the cell cycle control, the lung cancer molecular pathogenesis, the catalog of known genetic alterations and the recent advances in global expression profiles in lung tumors, on the basis of the various hystological types too. Such data suggest the potential use of this knowledges in clinical practice both as prognostic factors and innovative therapeutic possibilities and they impose the necessity of new studies about cell cycle control and lung carcinogenesis.
Open Access
Chk1/2 inhibitor AZD7762 blocks the growth of preantral follicles by inducing apoptosis, suppressing proliferation, and interfering with the cell cycle in granulosa cells
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2023) Liu, Xiao Ming; Chen, Fang; Zhang, Fan; Zhao, Jun Zhao
Background. Checkpoint kinases 1/2 (Chk1/2) have an important role in somatic cell development and oocyte meiotic maturation. However, the role of Chk1/2 in folliculogenesis has not been fully elucidated. The aim of this study was to assess the effects of Chk1/2 inhibition on ovarian folliculogenesis and granulosa cell development in mice. Methods. Preantral follicles (100-120 μm) and granulosa cells from pre-ovulatory follicles (pre-GCs) of mice were isolated and cultured with or without Chk1/2 inhibitor AZD7762. Preantral follicles were cultured for 96h. Then, follicle morphology and follicular growth were assessed every 48h. Granulosa cells were cultured for 48h with or without AZD7762, after which cell apoptosis, cell proliferation, and cell cycle analysis were assessed; meanwhile, the mRNA expression of PCNA and Bax were measured by real-time RT-PCR, and PCNA and Bax protein were measured by Western blot. Results. Compared with control follicles, AZD7762 inhibited growth of preantral follicles (P<0.05). Furthermore, inhibition of Chk1/2 significantly induced apoptosis (P<0.05) and inhibited the proliferation of granulosa cells (P<0.01), arrested cell cycle at S and G2/M phases, and decreased G1 phase fraction (P<0.001). Also, the expression of PCNA mRNA and protein were reduced (P<0.01), while Bax mRNA and protein were increased (P<0.05) post AZD7762 treatment in granulosa cells. Conclusions. This study revealed that Chk1 and Chk2 have a crucial role during preantral follicular development by regulating the proliferation and apoptosis of granulosa cells.
Open Access
Clinical applications of detecting dysfunctional p53 tumor suppressor protein
(Murcia : F. Hernández, 1999) Baas, I.O.; Hruban, R.H.; Offerhaus, G.J.A.
The p53 gene encodes for a protein, p53, which plays a critical role in controlling the cell cycle, in DNA repair and in programed cell death (apoptosis). p53 is one of the most frequently mutated genes in human neoplasms and a variety of techniques have been developed to detect these mutations. These range from advanced molecular-genetic analyses to immunohistochemical staining for the p53 protein. This review will summarize our current understanding of the function of p53 as well as current methods to detect dysfunctional p53 and the clinical value of such analyses.
Open Access
Differential proliferation of rat aortic and mesenteric smooth muscle cells in culture
(Murcia : F. Hernández, 1992) Waldbillig, David K.; Pang, Stephen C.
Smooth muscle cells (SMC) from various arterial origins have been successfully maintained in culture. The present study evaluates the proliferative activity of aortic and mesenteric SMC in culture. Aortic and mesenteric SMC were obtained from male Wistar rats by explant and enzyme digestion techniques, respectively. Vascular SMC obtained by either method exhibited a characteristic hill-and-valley growth pattern in culture after confluence and were positively labelled with either anti-smooth muscle actin or myosin by an indirect immunofluorescent method. The rate of incorporation of thymidine into DNA and cell number counting were used as indices of proliferation in vitro. Vascular SMC from passages 4-33 were first synchronized with either Dullbecco's Modified Eagle's Medium (DME) or Ham's F-12 medium, supplemented with insulin-transfemngselenium (ITS), for 72 hours. SMC were then stimulated with 10% bovine serum for either 24 or 72 hours with the former processed for scintillation counting, the latter for cell number determination. The incorporation of tritiated thymidine into DNA following a 2 hour incubation was determined by scintillation counting after perchloric acid extraction. In terms of cell numbers, proliferative responses to bovine serum were determined by Coulter counting. Autoradiography was also carried out in some cultures to determine both thymidine and mitotic labelling indices. The rate of thymidine incorporation in aortic cells was 2-3 fold higher than in mesenteric cells. Aortic and mesenteric SMC lines exhibited similar cell cycle intervals in terms of total duration and individuals cycle parameters. However, the total thymidine index was higher in the aortic than mesenteric SMC. These results suggest that SMC from different arterial origins possess different rates of proliferation. Differences in the rate of in vitro proliferation in these cell lines are due to differences in growth fraction, the number of celis traversing the cell cycle. The mechanisms underlying these differential proliferative potentials remain to be determined.
Open Access
Epithelial component and intraepithelial lymphocytes of conjunctiva-associated lymphoid tissue in healthy children
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2021) Cano-Suárez, Magnolia T.; Reinoso, Roberto; Martín, Carmen; Calonge, Margarita; Vallelado, Ana I.; Fernández, Itziar; Corell, Alfredo
. Conjunctiva-associated lymphoid tissue (CALT) plays a key role in protecting the eye surface by initiating and regulating immune responses. The aim of this study was to investigate in healthy children the proportion of intraepithelial lymphocytes (IELs), the degree of viability and/or apoptosis and cell proliferation in three different topographic areas of the conjunctiva. Superior tarsal, superior bulbar, and inferior tarsalbulbarfornix conjunctival cells were collected by brush cytology (BC) from 24 healthy paediatric subjects (13 boys and 11 girls, mean age 6±2 years) who were to undergo strabismus correction surgery under general anaesthesia. Subsequently, these cells were analysed phenotypically and functionally by flow cytometry (FC). Flow cytometry analysis showed that not all the cells obtained by BC were of the epithelial lineage, but that there was a population of CD45+ cells (IELs) regularly present in the conjunctiva of healthy children. These IELs were mostly T-lymphocytes (CD3+) and Blymphocytes (CD19+), with higher levels of Tlymphocytes (CD3+) in the upper areas than in the inferior tarsal-bulbar-fornix, where the highest levels of B-lymphocytes (CD19+) were found. In the apoptosis assay, two groups of cell populations were differentiated by cell size and complexity (cytoplasmic granularity), with more complex cells predominating in the upper areas of the conjunctiva and less complex cells being more abundant in the inferior tarsal-bulbar-fornix. Finally, the proliferative capacity of the conjunctival epithelium was significantly higher in the upper tarsal zone than in the rest of the zones analysed. These results suggest that the epithelial component and the IELs of CALT are also regularly present in the conjunctiva of the healthy child, varying in phenotype, viability and cell proliferation according to the different conjunctival regions analysed, which could lead us to believe that each conjunctival zone plays a different, specific role in the regulation of the immune response at the ocular level.
Open Access
Expression and function of cell cycle proteins in rheumatoid arthritis synovial tissue
(Murcia : F. Hernández, 2006) Taranto, E.; Leech, M.
Rheumatoid Arthritis (RA) is a chronic disease characterised by synovial lining hyperplasia and progressive destruction of joint tissues. Experimental data suggests that abnormal alterations in the expression of proteins involved in maintaining homeostatic control of the cell cycle is involved in disease progression in RA. By contributing to the overgrowth of synovial tissue, factors such as dysregulated proliferation or reduced apoptosis of cells can directly influence the pathological outcome of RA.
Open Access
Expression of cyclin D3 and cyclin E and identification of distinct clusters of proliferation and apoptosis in diffuse large B-cell lymphomas
(Murcia : F. Hernández, 2003) Bai, M.; Tsanou, E.; Agnantis, N.J.; Chaidos, A.; Dimou, D.; Skyrlas, A.; Dimou, S.; Vlychou, M.; Galani, V.; Kanavaros, Panagiotis
In the present study 79 cases of de novo Diffuse Large B-cell Lymphomas (DLBCL) were studied in order: a) to analyse the expression of cyclin D3, cyclin E and cyclin D1 in relation to other proliferative features (expression of Ki67, cyclin A and cyclin B1), the apoptosis status and the expression of p53, Rb, p16 and p27; and b) to determine whether distinct clusters of proliferation and apoptosis could be identified in DLBCL. Overexpression of cyclin D3 and cyclin E was found in 35/79 (43%) and 18/79 (22%) cases, respectively, whereas overexpression of cyclin D1 was not detected in any case. In most cases (39/46) overexpression of cyclin D3 and cyclin E was mutually exclusive possibly reflecting different underlying pathways inducing deregulated expression of these cyclins. In most cases (29/35) overexpression of cyclin D3 was mutually exclusive with Rb/p16 aberrant expression status supporting an oncogenic role for cyclin D3 and suggesting that the pathogenetic effect of cyclin D3 overexpression occurs through perturbation of the Rb1 pathway. Combined alterations of the P53 and the Rb/p16/cyclin D3 expression status were significantly associated with higher mean values of cyclin A (p=0.023) and cyclin B1 (p=0.033) indicating that concurrent impairment of the p53 and Rb1 pathways induces increased tumour cell proliferation in DLBCL. Cluster analysis of the apoptosis and the proliferation status permitted separation of DLBCL into distinct groups with low (44 cases) and high (18 cases) apoptotic activity and into distinct groups with low (32 cases), intermediate (36 cases) and high (11 cases) proliferative activity. The identification of distinct clusters with respect to the proliferation and the apoptosis status indicates that groups with distinct cellular kinetic properties can be defined in the histological group of DLBCL.
Open Access
Gain of function properties of mutant p53 proteins at the mitotic spindle cell cycle checkpoint
(Murcia : F. Hernández, 2000) Hixon, M.L.; Flores, A.; Wagner, M.; Gualberto, A.
Mutations in the p53 tumor suppressor gene locus predispose human cells to chromosomal instability. This is due in part to interference of mutant p53 proteins with the activity of the mitotic spindle and postmitotic cell cycle checkpoints. Recent data demonstrates that wild type p53 is required for postmitotic checkpoint activity, but plays no role at the mitotic spindle checkpoint. Likewise, structural dominant p53 mutants demonstrate gain-of-function properties at the mitotic spindle checkpoint and dominant negative properties at the postmitotic checkpoint. At mitosis, mutant p53 proteins interfere with the control of the metaphase-toanaphase progression by up-regulating the expression of CKsl, a protein that mediates activatory phosphorylation of the anaphase promoting complex (APC) by Cdc2. Cells that carry mutant p53 proteins overexpress CKsl and are unable to sustain APC inactivation and mitotic arrest. Thus, mutant p53 gain-of-function at mitosis constitutes a key component to the origin of chromosomal instability in mutant p53 cells.
Open Access
Identification of new tissue markers for the monitoring and standardization of penile cancer according to the degree of differentiation
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Casanova Martín, Carlos; Liviu Boaru, Diego; Fraile Martínez, Oscar; García Montero, Cielo; Leon Oliva, Diego De; Castro Martinez, Patricia De; Gimeno Longas, Maria José; Buján, Julia; García Honduvilla, Natalio; Guijarro, Luis G; Gragera, Raquel; López González, Laura; Saez, Miguel A.; Ferrara Coppola, Connie; Baena Romero, Víctor; Diaz Pedrero, Raul; Alvarez Mon, Melchor; Toledo Lobo, M. Val; Ortega, Miguel A.; Biología Celular e Histología
Penile cancer is an uncommon disease compared with other urological tumors and is more common in low- and middle-income countries. Risk factors include age, ethnicity, smoking, hygiene, and human papillomavirus infection. Although carcinoma of the penis can be cured in up to 80% of cases if detected early, late diagnosis drastically reduces survival rates, especially in metastatic cases. More than 95% of cases are squamous cell carcinomas, and the degree of cell differentiation is a key histopathological factor, distinguishing between poorly (P), moderately (M), and well-differentiated (W) carcinomas, with verrucous carcinoma (V) having the best prognosis due to its low metastatic capacity. This study analyses the differential expression of several biomarkers related to cell proliferation and cell cycle, inflammation, epigenetics, and autophagy (cell cycle (IRS-4, Ki-67, RB1, CDK4, cyclin D1, ERBB2, β-catenin, and MAGE-A), inflammation (COX2, NLRP3, and AIF-1), epigenetics (HAT-1) and autophagy (ULK-1 and ATG9A) in penile carcinoma according to the degree of differentiation. Immunohistochemical techniques were performed on 34 penile squamous cell carcinoma (PSCC) samples classified into subtype V (N=6), and groups P (N=9), M (N=9), and W (N=10). The findings suggest a differential expression of molecules according to the degree of cell differentiation, with a higher differential expression of molecules according to the degree of cell differentiation, suggesting that the proteins studied could have predictive value. The study highlights the complexity of PSCC and the need for future studies to explore translational applications and search for new biomarkers to improve clinical management and understanding of this disease
Open Access
In vitro modifications in the proliferation
(Murcia : F. Hernández, 1995) Carretero, J.; Rubio, M.; Navarro, N.; Prieto, P.; Vázquez, R.J.; Sanchez, F.; Vazquez, R.
In order to establish the correlation between in vitro proliferation rate and morphometric variations of prolactin immunoreactive cells, a morphometric study was carried out in rat pituitary monolayer cultures by means of the double immunocytochemical staining methods employing mouse monoclonal antiproliferative cell nuclear antigen (PCNA) and rabbit anti-prolactin (PRL) as primary antibodies. PCNA was found to be an adequeate marker for proliferation in pituitary monolayer cultures. 48.35+2.78% of the cells present in the culture were in active cell cycle after 3 days of incubation and a similar proportion, 54.93&2.83% was found after 7 days. On the 3rd day, PRL imrnunopositive cells accounted for 15.16*0.21% of the total cellular content in the dishes and 8.68*0.12% of the PCNA immunoreactive cells were also PRL immunopositive cells and, 60.95112.65% of PRL cells stained for PRL and PCNA. On the 7th day, an increase to 32.18f 0.60% of PRL cells was found; the PCNA and PRL cells accounted for 60.32*2.34% of the total PRL cells, and 19.88I1.09% of the PCNA reactive cells stained for PRL. Additionally, the morphometric analysis performed after 3 or 7 days of incubation showed that, while the size of PRL cells remained unmodified, the nuclear area had increased on the 7th day in relation to the 3rd day (pc0.01). These results suggest: 1) PCNA is a valid proliferative marker for pituitary cells in cultures; 2) a very high percentage of the PRL cells was in early proliferation; 3) on the 7th day of incubation, the proliferative rate of PRL cells was very similar to that observed on the 3rd day, suggesting a maintained proliferation for PRL cells at early incubation phases; and 4) the cellular activity, expressed as variations in the nuclear size, was higher on the 7th day than on the 3rd day; in addition, the numerical density of PRL cells increased.
Open Access
Interactions between Epstein-Bar rvirus and the cell cycle control machinery
(Murcia : F. Hernández, 1998) Sinclair, A.J.; Fenton, M.; Delikat, S.
Epstein-Barr virus (EBV) persists in the majority of the world's human population. In the majority of cases the infection is asymptomatic, but EBV is associated with a number of human diseases, such as infectious mononucleosis, Burkitt's lyrnphorna, nasopharyngeal carcinoma, Hodgkin's disease, gastric carcinomas and other lymphomas and lymphoproliferative diseases. In this review the evidence linking EBV with these diseases is reviewed together with recent advances i n understanding the interactions between EBV and the cell cycle control machinery.
Open Access
lmmunohistochemical expression of p53, p21/waf1, Rb, p16, cyclin D1, p27, Ki67, cyclin A, cyclin B1, bcl2 bax and bak proteins and apoptotic index in normal thymus
(Murcia : F. Hernández, 2001) Kanavaros, Panagiotis; Stefanaki, K.; Rontogianni, D.; Papalazarou, D.; Sgantzos, M.; Arvanitis, D.; Vamvouka, C.; Gorgoulis, V.; Siatitsas, I.; Agnantis, N.J.; Bai, M.
The immunohistochemical expression of p53, p21, Rb, p16, cyclin D1, Ki67, cyclin A, cyclin B1, p27, bc12, bax, and bak proteins and the apoptotic index (AI) were investigated in 20 normal thymuses (8 adults, 3 adolescents, 5 infants and 4 newborns). The expressions of Rb, Ki67, cyclin A and cyclin B1 were overlapping, being high in the cortex with a tendency for decreased expression toward the medulla. Apoptotic cells were mainly detected in the cortex and the corticomedullary junction, rarely being present in Hassall's corpuscles. The mean values of Ki67, cyclin A, and cyclin B1 expression in thymuses were 77.2%, 32.2% and 21.4% (newborns), 62.4%, 33.7% and 18.5% (infants), 56.9%, 23.4% and 18.9% (adolescents) and 38.7%, 21.7% and 14.6% (adults), respectively. The mean values of AI in thymuses from newborns, infants, adolescents and adults were 1.4%, 2.9%, 2.7% and 3.8%, respectively. This decrease in proliferation and increase in apoptosis may account for the process of thymic involution. P16 expression was widespread with most of Hassall's corpuscles being pl6-positive. P16- positive cells and Hassall's corpuscles increased with the increase in age, in keeping with the suggested role of p16 in cellular senescence. P27 expression was undetectable in subcapsular thymocytes with a tendency for increased expression toward the medulla. The expressions of Ki67, cyclin A and cyclin R1 were inversly related with that of p27, consistent with previous evidence that p27 concentration is reduced when the cell-cycle progresses. P21 and much less frequently p53 proteins were mainly detected in a part of the subcapsular cortical epithelial cells. These findings suggest that a) in thymocytes, the apoptotic pathway is mostly p53-independent and the function of p21 as a negative regulator of the cell cycle must be redundant to other negative regulators, such as p16 and p27 which were abundantly detected in thymocytes and b) in some thymic epithelial cells, the p21 expression may be induced by p53, but in most of them seems to be p53- independent. Most of Hassall's corpuscles were p21- positive, consistent with previous evidence that these structures represent end stages of maturation of thymic medullary epithelium and that p21 protein is involved in the process of terminal differentiation. Cyclin D1 positivity was found in some macrophages. Rc12 expression was mainly seen in medullary thymocytes, reflecting the surviving thymocytes in this region. The expressions of Bax and bak were more widespread in both the medulla and cortex, suggesting that these proteins play a broader role than bc12 in the regulation of thymic apoptosis.
Open Access
Mahogunin ring finger 1 is required for genomic stability and modulates the malignant phenotype of melanoma cells.
(MDPI, 2020-10-01) Martínez-Vicente, Idoya; Abrisqueta, Marta; Herraiz Serrano, Cecilia; Bennett, Dorothy C.; Olivares, Conchi; García-Borrón, José Carlos; Jiménez-Cervantes, Celia; Sirés-Campos, Julia; Castejón‐Griñán, María; Bioquímica y Biología Molecular B e Inmunología
The mouse mahoganoid mutation abrogating Mahogunin Ring Finger‐1 (MGRN1) E3 ubiquitin ligase expression causes hyperpigmentation, congenital heart defects and neurodegeneration. To study the pathophysiology of MGRN1 loss, we compared Mgrn1‐knockout melanocytes with genetically matched controls and melan‐md1 (mahoganoid) melanocytes. MGRN1 knockout induced a more differentiated and adherent phenotype, decreased motility, increased the percentage of cells in the S phase of the cell cycle and promoted genomic instability, as shown by stronger γH2AX labelling, increased burden of DNA breaks and higher abundance of aneuploid cells. Lack of MGRN1 expression decreased the ability of melanocytes to cope with DNA breaks generated by oxidizing agents or hydroxyurea‐induced replicative stress, suggesting a contribution of genomic instability to the mahoganoid phenotype. MGRN1 knockout in B16‐F10 melanoma cells also augmented pigmentation, increased cell adhesion to collagen, impaired 2D and 3D motility and caused genomic instability. Tumors formed by Mgrn1‐KO B16‐F10 cells had lower mitotic indices, fewer Ki67‐positive cells and showed a trend towards smaller size. In short‐term lung colonization assays Mgrn1‐KO cells showed impaired colonization potential. Moreover, lower expression of MGRN1 is significantly associated with better survival of human melanoma patients. Therefore, MGRN1 might be an important phenotypic determinant of melanoma cells.
Open Access
Molecular pathology of head and neck cancer
(Murcia : F. Hernández, 2002) Crowe, D.L.; Hacia, J.G.; Hsieh, C.L.; Sinha, U.K.; Rice, D.H.
Squamous cell carcinoma of the head and neck region (HNSCC) is the sixth most frequent cancer worldwide, comprising almost 50% of all malignancies in some developing nations. In the United States, 30,000 new cases and 8,000 deaths are reported each year. Survival rates vary depending on tobacco and alcohol consumption, age, gender, ethnic background, and geographic area. This variability reflects the multifactorial pathogenesis of the disease. Early detection and diagnosis has increased survival but the overall 5 year rate of 50% is among the lowest of the major cancers. Differences between normal epithelium and cancer cells of the upper aerodigestive tract arise from specific alterations in genes controlling DNA repair, proliferation, immortalization, apoptosis, invasion, and angiogenesis. These proteins include both tumor suppressors and activating oncogenes which regulate a wide variety of intracellular signaling pathways. Included in these pathways are growth factor receptors, signal transducers, and transcription factors which regulate DNA damage response, cell cycle arrest, and programmed cell death. In head and neck cancer, alterations of three signaling pathways occur with sufficient frequency and produce such dramatic phenotypic changes as to be considered the critical transforming events of the disease. These changes include mutation of the p53 tumor suppressor, inactivation of the cyclin dependent kinase inhibitor p16, and overexpression of epidermal growth factor receptor (EGFR). This review will focus on the molecular changes which occur in these pathways and how they contribute to the pathogenesis of HNSCC.
Open Access
Post-translational modifications of p53 tumor suppressor: determinants of its functional targets
(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2012) Taira, Naoe; Yoshida, Kiyotsugu
Tumor suppressor p53 functions as a “guardian of the genome” to prevent cells from transformation. p53 is constitutively ubiquitinated and degradated in unstressed conditions, thereby suppressing the expression. However, cellular stimuli enable p53 to escape from the negative regulation, and then stably expressed p53 transactivates its target genes to induce cell cycle arrest, DNA repair, or apoptosis. Promoter preference of target genes is determined by modification status of p53. Because p53 has two critical roles in the decision of cell fate, stopping cell cycle to repair damaged DNA or induction of apoptotic cell death in response to DNA damage, elucidation of switching mechanisms on p53 functions is of particular importance. Here we review recent evidence how several post-translational modifications of p53 including methylation, phosphorylation, acetylation, and ubiquitination, affect the functions of p53 in response to cellular stress