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Full-Text Articles in Medical Cell Biology

Il-7 Is A Critical Factor In Modulating Lesion Development In Skn-Directed Autoimmunity, Pamela Staton, A. Carpenter, Susan Jackman Sep 2012

Il-7 Is A Critical Factor In Modulating Lesion Development In Skn-Directed Autoimmunity, Pamela Staton, A. Carpenter, Susan Jackman

Pamela J. Staton

In a murine model of autoimmunity targeted against the epidermal cell Ags, Skn, adoptive transfer of Skn-immune T cells to immunosuppressed recipients elicits skin lesions in areas of mild epidermal trauma. In this study, we examined peripheral regulation of Skn-induced autoreactivity disrupted by rendering the mice immunoincompetent. We found that regulation of Skn-directed autoimmunity was restored by cotransfer of normal syngeneic spleen cells at twice the concentration of Skn-immune cells and was evidenced by significantly reduced lesion severity by days 5–7 post-cotransfer compared with animals given injections of Skn-immune cells alone. Enrichment and depletion of normal CD4 or CD8 spleen …


Mg624, An A7-Nachr Antagonist, Inhibits Angiogenesis Via The Egr-1/Fgf2 Pathway, Kathleen Brown, Jamie Lau, Aaron Dom, Theodore Witte, Haitao Luo, Clayton Crabtree, Yashoni Shah, Brandon Shiflett, Aileen Marcelo, Nancy Proper, W. Hardman, Richard Egleton, Yi Chen, Elsa Mangiarua, Piyali Dasgupta Sep 2012

Mg624, An A7-Nachr Antagonist, Inhibits Angiogenesis Via The Egr-1/Fgf2 Pathway, Kathleen Brown, Jamie Lau, Aaron Dom, Theodore Witte, Haitao Luo, Clayton Crabtree, Yashoni Shah, Brandon Shiflett, Aileen Marcelo, Nancy Proper, W. Hardman, Richard Egleton, Yi Chen, Elsa Mangiarua, Piyali Dasgupta

Richard D. Egleton

Small cell lung cancer (SCLC) demonstrates a strong etiological association with smoking. Although cigarette smoke is a mixture of about 4,000 compounds, nicotine is the addictive component of cigarette smoke. Several convergent studies have shown that nicotine promotes angiogenesis in lung cancers via the α7-nicotinic acetylcholine receptor (α7-nAChR) on endothelial cells. Therefore, we conjectured that α7-nAChR antagonists may attenuate nicotine-induced angiogenesis and be useful for the treatment of human SCLC. For the first time, our study explores the anti-angiogenic activity of MG624, a small-molecule α7-nAChR antagonist, in several experimental models of angiogenesis. We observed that MG624 potently suppressed the proliferation …


Capsaicin Displays Anti-Proliferative Activity Against Human Small Cell Lung Cancer In Cell Culture And Nude Mice Models Via The E2f Pathway, Kathleen C. Brown, Theodore R. Witte, W. Elaine Hardman, Haitao Luo, Yi C. Chen, A. Betts Carpenter, Jamie K. Lau, Piyali Dasgupta Sep 2012

Capsaicin Displays Anti-Proliferative Activity Against Human Small Cell Lung Cancer In Cell Culture And Nude Mice Models Via The E2f Pathway, Kathleen C. Brown, Theodore R. Witte, W. Elaine Hardman, Haitao Luo, Yi C. Chen, A. Betts Carpenter, Jamie K. Lau, Piyali Dasgupta

Piyali Dasgupta

Background: Small cell lung cancer (SCLC) is characterized by rapid progression and low survival rates. Therefore, novel therapeutic agents are urgently needed for this disease. Capsaicin, the active ingredient of chilli peppers, displays antiproliferative activity in prostate and epidermoid cancer in vitro. However, the anti-proliferative activity of capsaicin has not been studied in human SCLCs. The present manuscript fills this void of knowledge and explores the anti-proliferative effect of capsaicin in SCLC in vitro and in vivo. Methodology/Principal Findings: BrdU assays and PCNA ELISAs showed that capsaicin displays robust anti-proliferative activity in four human SCLC cell lines. Furthermore, capsaicin potently …


Mg624, An A7-Nachr Antagonist, Inhibits Angiogenesis Via The Egr-1/Fgf2 Pathway, Kathleen Brown, Jamie Lau, Aaron Dom, Theodore Witte, Haitao Luo, Clayton Crabtree, Yashoni Shah, Brandon Shiflett, Aileen Marcelo, Nancy Proper, W. Hardman, Richard Egleton, Yi Chen, Elsa Mangiarua, Piyali Dasgupta Sep 2012

Mg624, An A7-Nachr Antagonist, Inhibits Angiogenesis Via The Egr-1/Fgf2 Pathway, Kathleen Brown, Jamie Lau, Aaron Dom, Theodore Witte, Haitao Luo, Clayton Crabtree, Yashoni Shah, Brandon Shiflett, Aileen Marcelo, Nancy Proper, W. Hardman, Richard Egleton, Yi Chen, Elsa Mangiarua, Piyali Dasgupta

Piyali Dasgupta

Small cell lung cancer (SCLC) demonstrates a strong etiological association with smoking. Although cigarette smoke is a mixture of about 4,000 compounds, nicotine is the addictive component of cigarette smoke. Several convergent studies have shown that nicotine promotes angiogenesis in lung cancers via the α7-nicotinic acetylcholine receptor (α7-nAChR) on endothelial cells. Therefore, we conjectured that α7-nAChR antagonists may attenuate nicotine-induced angiogenesis and be useful for the treatment of human SCLC. For the first time, our study explores the anti-angiogenic activity of MG624, a small-molecule α7-nAChR antagonist, in several experimental models of angiogenesis. We observed that MG624 potently suppressed the proliferation …


Effect Of Dna Damage On Pcr Amplification Efficiency With The Relative Threshold Cycle Method, Jan Sikorsky, Donald Primerano, Terry Fenger, James Denvir Sep 2012

Effect Of Dna Damage On Pcr Amplification Efficiency With The Relative Threshold Cycle Method, Jan Sikorsky, Donald Primerano, Terry Fenger, James Denvir

James Denvir

Polymerase stop assays used to quantify DNA damage assume that single lesions are sufficient to block polymerase progression. To test the effect of specific lesions on PCR amplification efficiency, we amplified synthetic 90 base oligonucleotides containing normal or modified DNA bases using real-time PCR and determined the relative threshold cycle amplification efficiency of each template. We found that while the amplification efficiencies of templates containing a single 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) were not significantly perturbed, the presence of a single 8-oxo-7,8-dihydro-2′-deoxyadenosine, abasic site, or a cis–syn thymidine dimer dramatically reduced amplification efficiency. In addition, while templates containing two 8-oxodGs separated by 13 …


Silencing And Re-Expression Of Retinoic Acid Receptor Beta2 In Human Melanoma, Jun Fan, Linda Eastham, Melinda Varney, Adam Hall, Nicolas Adkins, Vincent Sollars, Philippe Georgel, Richard Niles Sep 2012

Silencing And Re-Expression Of Retinoic Acid Receptor Beta2 In Human Melanoma, Jun Fan, Linda Eastham, Melinda Varney, Adam Hall, Nicolas Adkins, Vincent Sollars, Philippe Georgel, Richard Niles

Philippe T. Georgel

Many melanoma cells are resistant to the anti-proliferative effect of all trans retinoic acid (ATRA). Retinoic Acid Receptor-β2 (RAR-β2) mediates the ATRA growth inhibition. We found a correlation between the anti-proliferative activity of ATRA and expression of RAR-β2. There was not a strict correlation between DNA methylation of RAR-β gene and its expression. There was no difference in global and RARβ specific nucleosome repeat length (NRL) in melanoma and melanocytes or between control and ATRA treated cells. Pan-acetylation of H3 and H4 within the RAR-β gene promoter was higher in cells expressing RAR-β2. All trans retinoic acid treatment of …


Effect Of Dna Damage On Pcr Amplification Efficiency With The Relative Threshold Cycle Method, Jan Sikorsky, Donald Primerano, Terry Fenger, James Denvir Sep 2012

Effect Of Dna Damage On Pcr Amplification Efficiency With The Relative Threshold Cycle Method, Jan Sikorsky, Donald Primerano, Terry Fenger, James Denvir

Terry W. Fenger

Polymerase stop assays used to quantify DNA damage assume that single lesions are sufficient to block polymerase progression. To test the effect of specific lesions on PCR amplification efficiency, we amplified synthetic 90 base oligonucleotides containing normal or modified DNA bases using real-time PCR and determined the relative threshold cycle amplification efficiency of each template. We found that while the amplification efficiencies of templates containing a single 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) were not significantly perturbed, the presence of a single 8-oxo-7,8-dihydro-2′-deoxyadenosine, abasic site, or a cis–syn thymidine dimer dramatically reduced amplification efficiency. In addition, while templates containing two 8-oxodGs separated by 13 …


Endothelial Cell Pseudopods And Angiogenesis Of Breast Cancer Tumors, Ivan Cameron, Nicholas Short, Luzhe Sun, W. Hardman Aug 2012

Endothelial Cell Pseudopods And Angiogenesis Of Breast Cancer Tumors, Ivan Cameron, Nicholas Short, Luzhe Sun, W. Hardman

Elaine Hardman Ph.D.

Background A neoplastic tumor cannot grow beyond a millimeter or so in diameter without recruitment of endothelial cells and new blood vessels to supply nutrition and oxygen for tumor cell survival. This study was designed to investigate formation of new blood vessels within a human growing breast cancer tumor model (MDA MB231 in mammary fat pad of nude female mouse). Once the tumor grew to 35 mm3, it developed a well-vascularized capsule. Histological sections of tumors greater than 35 mm3were stained with PAS, with CD-31 antibody (an endothelial cell maker), or with hypoxia inducible factor 1α antibody (HIF). The extent …


Mg624, An A7-Nachr Antagonist, Inhibits Angiogenesis Via The Egr-1/Fgf2 Pathway, Kathleen Brown, Jamie Lau, Aaron Dom, Theodore Witte, Haitao Luo, Clayton Crabtree, Yashoni Shah, Brandon Shiflett, Aileen Marcelo, Nancy Proper, W. Hardman, Richard Egleton, Yi Chen, Elsa Mangiarua, Piyali Dasgupta Aug 2012

Mg624, An A7-Nachr Antagonist, Inhibits Angiogenesis Via The Egr-1/Fgf2 Pathway, Kathleen Brown, Jamie Lau, Aaron Dom, Theodore Witte, Haitao Luo, Clayton Crabtree, Yashoni Shah, Brandon Shiflett, Aileen Marcelo, Nancy Proper, W. Hardman, Richard Egleton, Yi Chen, Elsa Mangiarua, Piyali Dasgupta

Elaine Hardman Ph.D.

Small cell lung cancer (SCLC) demonstrates a strong etiological association with smoking. Although cigarette smoke is a mixture of about 4,000 compounds, nicotine is the addictive component of cigarette smoke. Several convergent studies have shown that nicotine promotes angiogenesis in lung cancers via the α7-nicotinic acetylcholine receptor (α7-nAChR) on endothelial cells. Therefore, we conjectured that α7-nAChR antagonists may attenuate nicotine-induced angiogenesis and be useful for the treatment of human SCLC. For the first time, our study explores the anti-angiogenic activity of MG624, a small-molecule α7-nAChR antagonist, in several experimental models of angiogenesis. We observed that MG624 potently suppressed the proliferation …


Capsaicin Displays Anti-Proliferative Activity Against Human Small Cell Lung Cancer In Cell Culture And Nude Mice Models Via The E2f Pathway, Kathleen C. Brown, Theodore R. Witte, W. Elaine Hardman, Haitao Luo, Yi C. Chen, A. Betts Carpenter, Jamie K. Lau, Piyali Dasgupta Aug 2012

Capsaicin Displays Anti-Proliferative Activity Against Human Small Cell Lung Cancer In Cell Culture And Nude Mice Models Via The E2f Pathway, Kathleen C. Brown, Theodore R. Witte, W. Elaine Hardman, Haitao Luo, Yi C. Chen, A. Betts Carpenter, Jamie K. Lau, Piyali Dasgupta

Elaine Hardman Ph.D.

Background: Small cell lung cancer (SCLC) is characterized by rapid progression and low survival rates. Therefore, novel therapeutic agents are urgently needed for this disease. Capsaicin, the active ingredient of chilli peppers, displays antiproliferative activity in prostate and epidermoid cancer in vitro. However, the anti-proliferative activity of capsaicin has not been studied in human SCLCs. The present manuscript fills this void of knowledge and explores the anti-proliferative effect of capsaicin in SCLC in vitro and in vivo. Methodology/Principal Findings: BrdU assays and PCNA ELISAs showed that capsaicin displays robust anti-proliferative activity in four human SCLC cell lines. Furthermore, capsaicin potently …


Therapeutic Electromagnetic Field (Temf) And Gamma Irradiation On Human Breast Cancer Xenograft Growth, Angiogenesis And Metastasis, Ivan L. Cameron, Luzhe Sun, Nicholas Short, W. Elaine Hardman, C. Douglas Williams Aug 2012

Therapeutic Electromagnetic Field (Temf) And Gamma Irradiation On Human Breast Cancer Xenograft Growth, Angiogenesis And Metastasis, Ivan L. Cameron, Luzhe Sun, Nicholas Short, W. Elaine Hardman, C. Douglas Williams

Elaine Hardman Ph.D.

Background The effects of a rectified semi-sinewave signal (15 mT amplitude, 120 pulses per second, EMF Therapeutics, Inc.) (TEMF) alone and in combination with gamma irradiation (IR) therapy in nude mice bearing a human MDA MB231 breast cancer xenograft were tested. Green fluorescence protein transfected cancer cells were injected into the mammary fat pad of young female mice. Six weeks later, mice were randomly divided into four treatment groups: untreated controls; 10 minute daily TEMF; 200 cGy of IR every other day (total 800 cGy); IR plus daily TEMF. Some mice in each group were euthanized 24 hours after the …


High Dietary Level Of Synthetic Vitamin E On Lipid Peroxidation, Membrane Fatty Acid Composition And Cytotoxicity In Breast Cancer Xenograft And In Mouse Host Tissue, Ivan L. Cameron, Jesus Munoz, Christopher J. Barnes, W. Elaine Hardman Aug 2012

High Dietary Level Of Synthetic Vitamin E On Lipid Peroxidation, Membrane Fatty Acid Composition And Cytotoxicity In Breast Cancer Xenograft And In Mouse Host Tissue, Ivan L. Cameron, Jesus Munoz, Christopher J. Barnes, W. Elaine Hardman

Elaine Hardman Ph.D.

Background d-α-tocopherol is a naturally occurring form of vitamin E not previously known to have antitumor activity. Synthetic vitamin E (sE) is a commonly used dietary supplement consisting of a mixture of d-α-tocopherol and 7 equimolar stereoisomers. To test for antilipid peroxidation and for antitumor activity of sE supplementation, two groups of nude mice bearing a MDA-MB 231 human breast cancer tumor were fed an AIN-76 diet, one with and one without an additional 2000 IU/kg dry food (equivalent to 900 mg of all-rac-α-tocopherol or sE). This provided an intake of about 200 mg/kg body weight per day. The mice …


Dietary Omega-3 Fatty Acids And Ionizing Irradiation On Human Breast Cancer Xenograft Growth And Angiogenesis, W. Elaine Hardman, Luzhe Sun, Nicholas Short, Ivan L. Cameron Aug 2012

Dietary Omega-3 Fatty Acids And Ionizing Irradiation On Human Breast Cancer Xenograft Growth And Angiogenesis, W. Elaine Hardman, Luzhe Sun, Nicholas Short, Ivan L. Cameron

Elaine Hardman Ph.D.

Background The effects of an omega-3 (n-3) fatty acid enriched diet alone and in combination with gamma irradiation (IR) therapy in nude mice bearing a human MDA-MB231 breast cancer xenograft were tested. The cancer cells were injected into the mammary fat pad of young female mice. Six weeks later, mice were randomly divided into two diet groups: 1) mice with 10% corn oil (rich in omega 6 fatty acids) in their food, 2) mice consuming a 10% fat diet that was enriched in n-3 fatty acids. After two weeks on the diet, treatment with 200 cGy of IR every second …


Differential Regulation Of Osteoblast Activity By Th Cell Subsets Mediated By Parathyroid Hormone And Ifn-, Nathan Young, Natallia Mikhalkevich, Ying Yan, Di Chen, Wei-Ping Zeng Aug 2012

Differential Regulation Of Osteoblast Activity By Th Cell Subsets Mediated By Parathyroid Hormone And Ifn-, Nathan Young, Natallia Mikhalkevich, Ying Yan, Di Chen, Wei-Ping Zeng

Wei-ping Zeng

Bone loss is a typical pathological feature of chronic inflammatory bone diseases including rheumatoid arthritis, in which CD4 effector T cells play critical roles. We found that activated mouse Th2 and not Th1 cells produced the parathyroid hormone (PTH). Unlike in the parathyroid cells, PTH expression in Th2 cells was not regulated by the fluctuation of calcium level, but rather it required the full activation of the T cells. Although PTH was expressed in immature Th2 cells, and its receptor was transiently expressed during Th1 and Th2 cell differentiation, PTH did not significantly affect the outcome of the differentiation. In …


Susceptibility To Autoimmunity And B Cell Resistance To Apoptosis In Mice Lacking Androgen Receptor In B Cells, Saleh Altuwaijri, Kuang-Hsiang Chuang, Kuo-Pao Lai, Jiann-Jyh Lai, Hung-Yun Lin, Faith Young, Andrea Bottaro, Meng-Yin Tsai, Wei-Ping Zeng, Hong-Chiang Chang, Shuyuan Yeh, Chawnshang Chang Aug 2012

Susceptibility To Autoimmunity And B Cell Resistance To Apoptosis In Mice Lacking Androgen Receptor In B Cells, Saleh Altuwaijri, Kuang-Hsiang Chuang, Kuo-Pao Lai, Jiann-Jyh Lai, Hung-Yun Lin, Faith Young, Andrea Bottaro, Meng-Yin Tsai, Wei-Ping Zeng, Hong-Chiang Chang, Shuyuan Yeh, Chawnshang Chang

Wei-ping Zeng

Estrogens have been linked to a higher female incidence of autoimmune diseases. The role of androgen and the androgen receptor (AR) in autoimmune diseases, however, remains unclear. Here we report that the lack of AR in B cells in different strains of mice, namely general AR knockout, B cell-specific AR knockout, and naturally occurring testicular feminization mutation AR-mutant mice, as well as castrated wild-type mice, results in increased B cells in blood and bone marrow. Analysis of the targeted mice, together with bone marrow transplantation using Rag1 recipients, overexpression of retrovirally encoded AR-cDNA, and small interfering RNA-mediated AR mRNA knockdown …


Responsiveness Of Naive Cd4 T Cells To Polarizing Cytokine Determines The Ratio Of Th1 And Th2 Cell Differentiation, Natallia Mikhalkevich, Brian Becknell, Michael Caligiuri, Michael Bates, Richard Harvey, Wei-Ping Zeng Aug 2012

Responsiveness Of Naive Cd4 T Cells To Polarizing Cytokine Determines The Ratio Of Th1 And Th2 Cell Differentiation, Natallia Mikhalkevich, Brian Becknell, Michael Caligiuri, Michael Bates, Richard Harvey, Wei-Ping Zeng

Wei-ping Zeng

The intrinsic features of naive CD4 T cells that affect their ability to respond to polarizing signals for Th cell differentiation are not well understood. In this study, we show that naive CD4 T cells from mice transgenic for the Hlx gene expressed lower levels of IL-4Rα. The down-regulation of IL-4Rα diminished IL-4 signaling and the Th2 response and enhanced the Th1 response under suboptimal polarizing conditions. In nontransgenic CD4 T cells, blocking IL-4Rα with Abs had the same effect in an Ab dose-dependent manner. Conversely, Hlx haploinsufficiency caused higher expression of IL-4Rα to favor Th2 cell differentiation. Thus, the …


Temporal And Spatial Changes Of Histone 3 K4 Dimethylation At The Ifn-Γ Gene During Th1 And Th2 Cell Differentiation, Heli Hamalainen-Laanaya, James Kobie, Chawnshang Chang, Wei-Ping Zeng Aug 2012

Temporal And Spatial Changes Of Histone 3 K4 Dimethylation At The Ifn-Γ Gene During Th1 And Th2 Cell Differentiation, Heli Hamalainen-Laanaya, James Kobie, Chawnshang Chang, Wei-Ping Zeng

Wei-ping Zeng

Covalent modification of nucleosomal histones is an important mechanism for cytokine gene regulation in Th1 and Th2 cells. In this study, we analyzed the kinetics of histone H3 K4 dimethylation (H3K4me2) of the IFN-γ gene. Minimal levels of H3K4me2 were found in naive CD4 T cells. After 5 days of differentiation, H3K4me2 levels were elevated in both Th1 and Th2 cells at the −5.3 kb, the promoter, the intronic DNase I hypersensitive sites, and 3′ distal sites including the +9.5 kb and +16 kb sites. Th1 cells maintained high levels of H3K4me2 after longer time of culture. However, in Th2 …


Up-Regulation Of Hlx In Immature Th Cells Induces Ifn-Γ Expression, Wei-Ping Zeng, Qian Zhao, Xinyan Zhao, Baiyong Li, Mike Hubank, David Schatz, Richard Flavell Aug 2012

Up-Regulation Of Hlx In Immature Th Cells Induces Ifn-Γ Expression, Wei-Ping Zeng, Qian Zhao, Xinyan Zhao, Baiyong Li, Mike Hubank, David Schatz, Richard Flavell

Wei-ping Zeng

Differentiation of Th cells from naive precursors is a dynamic process that involves multiple transcription factors acting at specific time points to regulate gene expression. In this study we show that the homeobox transcription factor Hlx is up-regulated early in Th1 cell differentiation. Mice constitutively expressing an Hlx transgene driven by a CD4 promoter showed marked reduction in the CD4+CD8+ thymocyte population. The Hlx transgenic mice generated increased numbers of Th1 cells in response to keyhole limpet hemocyanin immunization. After differentiation under Th2-polarizing conditions in vitro, the transgenic CD4 T cells expressed high levels of IFN-γ. Intracellular …


Ybx1 Expression And Function In Early Hematopoiesis And Leukemic Cells, Jasjeet Bhullar, Vincent Sollars Aug 2012

Ybx1 Expression And Function In Early Hematopoiesis And Leukemic Cells, Jasjeet Bhullar, Vincent Sollars

Vincent E Sollars

Hematopoietic transcription factors play a critical role in directing the commitment and differentiation of hematopoietic stem cells along a particular lineage. Y-box protein (YBX1) is a transcription factor which is widely expressed throughout development and is involved in erythroid cell development; however, its role in early hematopoietic differentiation is not known. This study aims to investigate the role of YBX1 expression in early hematopoietic differentiation and leukemia. Here, we show that YBX1 is highly expressed in mouse erythroid myeloid lymphoid-clone 1 (EML), a hematopoietic precursor cell line, but is down-regulated in myeloid progenitors and GM-CSF-treated EML cells during the course …


Silencing And Re-Expression Of Retinoic Acid Receptor Beta2 In Human Melanoma, Jun Fan, Linda Eastham, Melinda Varney, Adam Hall, Nicolas Adkins, Vincent Sollars, Philippe Georgel, Richard Niles Aug 2012

Silencing And Re-Expression Of Retinoic Acid Receptor Beta2 In Human Melanoma, Jun Fan, Linda Eastham, Melinda Varney, Adam Hall, Nicolas Adkins, Vincent Sollars, Philippe Georgel, Richard Niles

Vincent E Sollars

Many melanoma cells are resistant to the anti-proliferative effect of all trans retinoic acid (ATRA). Retinoic Acid Receptor-β2 (RAR-β2) mediates the ATRA growth inhibition. We found a correlation between the anti-proliferative activity of ATRA and expression of RAR-β2. There was not a strict correlation between DNA methylation of RAR-β gene and its expression. There was no difference in global and RARβ specific nucleosome repeat length (NRL) in melanoma and melanocytes or between control and ATRA treated cells. Pan-acetylation of H3 and H4 within the RAR-β gene promoter was higher in cells expressing RAR-β2. All trans retinoic acid treatment of …


Waddington’S Widget: Hsp90 And The Inheritance Of Acquired Characters, Douglas Ruden, Mark Garfinkel, Vincent Sollars, Xiangyi Lu Aug 2012

Waddington’S Widget: Hsp90 And The Inheritance Of Acquired Characters, Douglas Ruden, Mark Garfinkel, Vincent Sollars, Xiangyi Lu

Vincent E Sollars

Conrad Waddington published an influential model for evolution in his 1942 paper, Canalization of Development and Inheritance of Acquired Characters. In this classic, albeit controversial, paper, he proposed that an unknown mechanism exists that conceals phenotypic variation until the organism is stressed. Recent studies have proposed that the highly conserved chaperone Hsp90 could function as a “capacitor,” or an “adaptively inducible canalizer,” that masks silent phenotypic variation of either genetic or epigenetic origin. This review will discuss evidence for, and arguments against, the role of Hsp90 as a capacitor for morphological evolution, and as a key component of what we …


Effect Of Dna Damage On Pcr Amplification Efficiency With The Relative Threshold Cycle Method, Jan Sikorsky, Donald Primerano, Terry Fenger, James Denvir Aug 2012

Effect Of Dna Damage On Pcr Amplification Efficiency With The Relative Threshold Cycle Method, Jan Sikorsky, Donald Primerano, Terry Fenger, James Denvir

Donald A Primerano

Polymerase stop assays used to quantify DNA damage assume that single lesions are sufficient to block polymerase progression. To test the effect of specific lesions on PCR amplification efficiency, we amplified synthetic 90 base oligonucleotides containing normal or modified DNA bases using real-time PCR and determined the relative threshold cycle amplification efficiency of each template. We found that while the amplification efficiencies of templates containing a single 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) were not significantly perturbed, the presence of a single 8-oxo-7,8-dihydro-2′-deoxyadenosine, abasic site, or a cis–syn thymidine dimer dramatically reduced amplification efficiency. In addition, while templates containing two 8-oxodGs separated by 13 …


Silencing And Re-Expression Of Retinoic Acid Receptor Beta2 In Human Melanoma, Jun Fan, Linda Eastham, Melinda Varney, Adam Hall, Nicolas Adkins, Vincent Sollars, Philippe Georgel, Richard Niles Aug 2012

Silencing And Re-Expression Of Retinoic Acid Receptor Beta2 In Human Melanoma, Jun Fan, Linda Eastham, Melinda Varney, Adam Hall, Nicolas Adkins, Vincent Sollars, Philippe Georgel, Richard Niles

Richard M Niles

Many melanoma cells are resistant to the anti-proliferative effect of all trans retinoic acid (ATRA). Retinoic Acid Receptor-β2 (RAR-β2) mediates the ATRA growth inhibition. We found a correlation between the anti-proliferative activity of ATRA and expression of RAR-β2. There was not a strict correlation between DNA methylation of RAR-β gene and its expression. There was no difference in global and RARβ specific nucleosome repeat length (NRL) in melanoma and melanocytes or between control and ATRA treated cells. Pan-acetylation of H3 and H4 within the RAR-β gene promoter was higher in cells expressing RAR-β2. All trans retinoic acid treatment of …


Pparα/Γ Expression And Activity In Mouse And Human Melanocytes And Melanoma Cells, Linda Eastham, Caroline Mills, Richard Niles Aug 2012

Pparα/Γ Expression And Activity In Mouse And Human Melanocytes And Melanoma Cells, Linda Eastham, Caroline Mills, Richard Niles

Richard M Niles

Purpose. We examined the expression of PPARs and the effects of PPARα and PPARγ agonists on growth of mouse and human melanocytes and melanoma cells.

Methods. PPARα,β, and PPARγ mRNA qualitative expression in melan-a mouse melanocytes, B16 mouse melanoma, human melanocytes, and A375 and SK-mel28 human melanoma cells was determined by RT-PCR, while quantitative PPARα mRNA levels were determined by QuantiGene assay. PPARα and PPARγ protein was assessed by Western blotting. The effect of natural and synthetic PPAR ligands on cell growth was determined by either hemocytometer counting or crystal violet assay. PPAR transcriptional activity was determined by a PPRE-reporter …