• The dose-fractionation sensitivity of the kidney; assessment of viable tubule cross-sections at 19 months after X irradiation.

      Jen, Yee-Min; Hendry, Jolyon H; Department of Experimental Radiation Oncology, Paterson Institute for Cancer Research, Christie Hospital (NHS) Trust, Manchester, UK. (1993-03)
      The formation of viable tubule cross-sections was assessed in histological sections of murine kidneys at 19 months after fractionated bilateral X-ray doses with 12 h intervals between fractions. The data were analysed using the linear-quadratic model which provides values of alpha and beta characterizing the slope of the dose-response curve, and the ratio of alpha and beta indicative of the sparing effect of dose fractionation. The tubule data were characterized by alpha = 0.057 +/- 0.009 Gy-1, beta = 0.011 +/- 0.001 Gy-2, alpha/beta = 5.0 +/- 0.9 Gy. Also, the number of cells (per focus region of the nephron) calculated as being capable of producing a viable focus was 2.5 +/- 0.5, which was confirmed using a separate two-dose approach (2.1 +/- 0.3). Together with other data, of the order of 1000 regenerative cells per nephron (10(4) total cells) can be deduced. The values of the fractionation sensitivity parameters are similar to values measured previously for cells taken from irradiated kidneys up to a year after irradiation and forming colonies in primary culture, and also similar to values assessed using various functional measures of kidney injury.
    • Dose-rate sparing for micronucleus induction in lymphocytes of controls and ataxia-telangiectasia heterozygotes exposed to 60Co gamma-irradiation in vitro.

      Scott, David; Hu, Qiuping; Roberts, Stephen A; Paterson Institute for Cancer Research, Christie CRC Research Centre, Manchester, UK. (1996-11)
      We investigated the reproducibility of the cytochalasin B micronucleus (MN) assay in irradiated human lymphocytes to assess its suitability in predicting cancer predisposition and response to radiotherapy by virtue of defects in the processing of clastogenic lesions. G0 lymphocytes were exposed to 3.0 Gy 60Co gamma-rays at high (HDR) or low dose-rate (LDR). Six healthy donors were assayed three times each in nine experiments and compared with six ataxia-telangiectasia (A-T) heterozygotes. In controls, significant interexperiment variability in MN yields was observed at HDR and LDR, also in dose-rate sparing (i.e. reduction in MN yield at LDR compared with HDR). Significant inter-individual variability was seen at HDR, but not at LDR or for sparing. Average sparing was 66.4 +/- 4.8%. In spite of the experimental variability, a significant difference between controls and A-T heterozygotes was detected at LDR, and 5/6 heterozygotes had sparing values below the control range. This gives encouragement for the use of this assay in predictive testing if sources of experimental variability can be identified so as to improve discrimination between individuals. HDR and to a lesser extent LDR irradiation induced significant mitotic inhibition, seen as a reduction in binucleate cells after cytocholasin treatment. A positive correlation between mitotic inhibition and MN frequency suggests that similar lesions may be involved in these effects.
    • Dose-response relationships for photodynamic injury to murine skin.

      Moore, James V; Keene, J P; Land, Edward J; Departments of Radiobiology, Physics and Instrumentation, and Biophysical Chemistry, Paterson Laboratories, Christie Hospital and Holt Radium Institute, Manchester M20 9BX (1986-03)
      Oedema and necrosis of murine tail skin have been measured after intravenous injection of haematoporphyrin derivative ("Photofrin", or PhI) followed 24 h later by graded exposures of the tail to full-spectrum visible light from a quartz-halogen lamp. End-points were degree of oedema and the proportion of mice in a dose-group that developed skin necrosis and tail atrophy. Oedema developed within 24 h of illumination and was a function of PhI dose and duration of light exposure. Onset of necrosis occurred after a minimum of 5 days and onset time was an inverse function of exposure time. Probit plots of proportion of necroses versus light exposure yielded values for ND50 (exposure corresponding to 50% incidence of necrosis) and l/slope. At the high but non-toxic dose of 2 mg PhI/mouse, ND50 was 18 min, l/slope 4 min, for pigmented BDF1 mice. Halving the PhI dose increased ND50 by a factor of 1.9. Albino BALB/c mice were markedly more sensitive to 2 mg PhI plus light than BDF1 mice: the ND50 was 7 min. Temporary occlusion of the blood supply to the tail (10 min before and during illumination) abrogated totally the oedematous and necrotic reactions to photodynamic therapy.
    • Dose-response relationships for radiation-related heart disease: Impact of uncertainties in cardiac dose reconstruction

      Ntentas, G.; Darby, S. C.; Aznar, Marianne Camille; Hodgson, D. C.; Howell, R. M.; Maraldo, M. V.; Ahmed, S.; Ng, A.; Aleman, B. M. P.; Cutter, D. J.; et al. (2020)
      Background and purpose: Radiation-related heart disease (RRHD) can occur many decades after thoracic radiotherapy for Hodgkin lymphoma (HL) or childhood cancer (CC). To quantify the likely risk of RRHD for patients treated today, dose-response relationships derived from patients treated in previous decades are used. Publications presenting these dose-response relationships usually include estimates of uncertainties in the risks but ignore the effect of uncertainties in the reconstructed cardiac doses. Materials/methods: We assessed the systematic and random uncertainties in the reconstructed doses for published dose-response relationships for RRHD risk in survivors of HL or CC. Using the same reconstruction methods as were used in the original publications, we reconstructed mean heart doses and, wherever possible, mean left-ventricular doses for an independent case-series of test patients. These patients had known, CT-based, cardiac doses which were compared with the reconstructed doses to estimate the magnitude of the uncertainties and their effect on the dose-response relationships. Results: For all five reconstruction methods the relationship between reconstructed and CT-based doses was linear. For all but the simplest reconstruction method, the dose uncertainties were moderate, the effect of the systematic uncertainty on the dose-response relationships was less than 10%, and the effects of random uncertainty were small except at the highest doses. Conclusions: These results increase confidence in the published dose-response relationships for the risk of RRHD in HL and CC survivors. This may encourage doctors to use these dose-response relationships when estimating individualised risks for patients-an important aspect of personalising radiotherapy treatments today.
    • Double labeling with bromodeoxyuridine and [H - 3]- thymidine of proliferative cells in small intestinal epithelium in steady-state and after irradiation

      Chwalinski, S; Potten, Christopher S; Evans, Gareth S; Christie Hosp & Holt Radium Inst, Paterson Inst Canc Res, Wilmslow Rd, Manchester M20 9BX, Lancs, England (1988)
    • The doubling time of regenerating clonogenic cells in the crypts of the irradiated mouse small intestine.

      Potten, Christopher S; Taylor, Y; Hendry, Jolyon H; Department of Epithelial Biology, Paterson Institute for Cancer Research, Christie Hospital, Manchester, U.K. (1988-12)
      The number of clonogenic cells per intestinal crypt has been estimated in control and gamma-irradiated mice, from the response to a single or two test doses. Control unirradiated mice contained 43 +/- 8 clonogenic cells per crypt, which was reduced to about 3 per crypt immediately after 8.0 Gy. After a mitotic delay which was approximately 18 h or 2.25 h/Gy the number of clonogenic cells per crypt increased exponentially with a doubling time of 21 +/- 4 h to reach the control values by about the 4th day postirradiation. The growth curve was related to the changes in total cellularity and the cell production rate per crypt. Since both of these rise during the period of clonogenic regrowth some clonogenic cells must be diverted into the dividing transit cell population, so that the cell cycle time will be shorter than the doubling time given above.
    • Down-Regulation of the Oncogene Cyclin D1 Increases Migratory Capacity in Breast Cancer and Is Linked to Unfavorable Prognostic Features.

      Lehn, Sophie; Tobin, Nicholas P; Berglund, P; Nilsson, K; Sims, A H; Jirström, K; Härkönen, P; Lamb, Rebecca; Landberg, Göran; From the Center for Molecular Pathology, Department of Laboratory Medicine,* Lund University, UMAS, Sweden; the Breakthrough Breast Cancer Research Unit, School of Cancer, Enabling Sciences and Technology, University of Manchester, Manchester Academic Health Science Centre, Paterson Institute for Cancer Research, The Christie NHS Foundation Trust, Manchester, United Kingdom; Applied Bioinformatics of Cancer, Breakthrough Breast Cancer Research Unit, Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, Edinburgh, United Kingdom; Tumor Biology, the Department of Laboratory Medicine, Lund University, Malmö University Hospital, Malmö, Sweden; and the Department of Anatomy, Institute of Biomedicine, University of Turku, Turku, Finland. (2010-10-22)
      The oncogene cyclin D1 is highly expressed in many breast cancers and, despite its proliferation-activating properties, it has been linked to a less malignant phenotype. To clarify this observation, we focused on two key components of malignant behavior, migration and proliferation, and observed that quiescent G0/G1 cells display an increased migratory capacity compared to cycling cells. We also found that the down-regulation of cyclin D1 in actively cycling cells significantly increased migration while also decreasing proliferation. When analyzing a large set of premenopausal breast cancers, we observed an inverse proliferation-independent link between cyclin D1 and tumor size and recurrence, suggesting that this protein might abrogate infiltrative malignant behavior in vivo. Finally, gene expression analysis after cyclin D1 down-regulation by siRNA confirmed changes in processes associated with migration and enrichment of our gene set in a metastatic poor prognosis signature. This novel function of cyclin D1 illustrates the interplay between tumor proliferation and migration and may explain the attenuation of malignant behavior in breast cancers with high cyclin D1 levels.
    • Down-regulation of XIAP by AEG35156 in paediatric tumour cells induces apoptosis and sensitises cells to cytotoxic agents.

      Holt, Sarah V; Brookes, Karen E; Dive, Caroline; Makin, Guy W J; Clinical and Experimental Pharmacology, Paterson Institute for Cancer Research, Manchester Cancer Research Centre, The University of Manchester, Wilmslow Road, Manchester M20 4BX, UK. (2011-04)
      Resistance to conventional chemotherapy is a major problem in several paediatric tumours. One explanation for this is that tumour cells are unable to engage apoptosis after cytotoxic drug-induced damage. Inhibitor of apoptosis proteins (IAPs) function by inhibiting both effector (9) and initiator (3 and 7) caspases. Repression of the widely expressed X-linked IAP (XIAP) by RNAi sensitises adult tumour cells to cytotoxics in vitro. Antisense oligonucleotide (ASO)-induced down-regulation of XIAP is effective at inducing cell death and delaying the growth of adult tumour cells as xenografts and these agents are currently in phase II clinical trials. The importance of XIAP in paediatric tumours has not been characterised but high expression correlates with poor survival in childhood AML. We have used the novel XIAP ASO (AEG35156) to evaluate the effects of down-regulation of XIAP in paediatric tumour cells. Here, we show that AEG35156 can down-regulate XIAP in a number of paediatric cell lines including models of osteosarcoma, rhabdomyosarcoma and Ewing's sarcoma. Cell death assays demonstrated a higher proportion of dead cells after XIAP down-regulation by ASO and these cells displayed increased levels of cleaved caspase-3 and cleaved PARP, showing cell death was due to apoptosis. In long-term clonogenic assays, XIAP ASO sensitised 791T osteosarcoma cells to doxorubicin, etoposide and vincristine. The work presented here suggests that AEG35156, as a monotherapy or in combination with cytotoxic agents, may be of benefit in the treatment of paediatric tumours.
    • Downregulation of miR-92a is associated with aggressive breast cancer features and increased tumour macrophage infiltration.

      Nilsson, Sofie; Möller, C; Jirström, K; Lee, Alexander; Busch, Susann; Lamb, Rebecca; Landberg, Göran; Center for Molecular Pathology, Department of Laboratory Medicine, Lund University, Skåne University Hospital, Malmö, Sweden. (2012)
      MicroRNAs are small non-coding RNAs involved in the regulation of gene expression on a posttranscriptional level. These regulatory RNAs have been implicated in numerous cellular processes and are further deregulated in different cancer types, including breast cancer. MiR-92a is part of the miR-17∼92 cluster, which was first reported to be linked to tumourigenesis. However, little is known about the expression of miR-92a in breast cancer and potential associations to tumour properties. The expression of miR-92a was therefore characterized in 144 invasive breast cancer samples using in situ hybridization and related to clinico-pathological data as well as to selected key properties of the tumour stroma, including the presence of macrophages (CD68) and cancer activated fibroblasts (alpha-SMA).
    • Dpb2 integrates the leading-strand DNA polymerase into the eukaryotic replisome.

      Sengupta, Sugopa; Van Deursen, Frederick; de Piccoli, Giacomo; Labib, Karim; Paterson Institute for Cancer Research, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK. (2013-04-08)
      The eukaryotic replisome is a critical determinant of genome integrity with a complex structure that remains poorly characterized. A central unresolved issue is how the Cdc45-MCM-GINS helicase is linked to DNA polymerase epsilon, which synthesizes the leading strand at replication forks and is an important focus of regulation.
    • DRFIT: a program for fitting radiation survival models.

      Roberts, Stephen A; Paterson Institute for Cancer Research, Christie Hospital, Manchester, UK. (1990-06)
    • Drug receptors and the haemopoietic stem cell.

      Byron, J W; Paterson Laboratories, Christie Hospital and Holt Radium Institute, Manchester (1973-01-31)
    • Drug resistance and DNA repair.

      Fox, Margaret; Roberts, J J; Paterson Institute for Cancer Research, Christie Hospital and Holt Radium Institute, Manchester, UK. (1987)
      DNA repair confers resistance to anticancer drugs which kill cells by reacting with DNA. A review of our current information on the topic will be presented here. Our understanding of the molecular biology of repair of 0(6)-alkylguanine adducts in DNA has advanced as a result of the molecular cloning of the E. coli ada gene but the precise role of this lesion in the cytotoxic effects of alkylating agents in mammalian cells is not completely understood. Less progress has been made in understanding the enzymology and molecular biology of DNA cross-link repair even though such lesions are important for the cytotoxic effects of the widely used bifunctional alkylating agents and platinum compounds. It is evident that drug sensitive or resistant phenotypes are as highly complex as are the effects of DNA damage on cell metabolism and various aspects of these effects are discussed. Few clear correlations have been made between quantitative differences in DNA repair capacity and cellular sensitivity but assays which were developed to measure fidelity and intragenomic heterogeneity in DNA repair are beginning to be applied. Such studies may reveal subtle differences between sensitive and resistant cell lines. The molecular cloning of human DNA repair genes by transfection into drug sensitive rodent cells has been attempted. Some success has been achieved in this area but the functions of the cloned genes have yet to be identified.
    • Drug-resistance associated alterations of cell surface antigen expression in a human anthracycline-resistant ovarian carcinoma cell line.

      Sedlák, J; McGown, Alan T; Hrubisko, M; Hunáková, L; Chorváth, B; Cancer Research Institute, Slovak Academy of Sciences, Bratislava. (1994)
      The anthracycline uptake and cell surface expression of plasma membrane antigens (HLA class I, c-erbB-2, protectin-CD59, integrin beta 1-chain-CD29, etc.) were compared on a parental anthracycline sensitive and an anthracycline-resistant subline of the human ovarian carcinoma cell line A2780. The anthracycline-resistant (A2780/ADR) subline incubated for 30 min in the presence of daunomycin displayed two subpopulations with different anthracycline cell content as determined by flow cytometry. The subpopulation with lower daunomycin cell content was absent in the parental anthracycline sensitive cell line. The most predominant antigenic changes on the resistant subline as compared with the sensitive one were as follow: Loss of HLA class I and a twofold increase in the expression of CD59 antigen and a slight decrease of integrin beta 1-chain on the cell surface of the resistant subline.
    • DT-diaphorase: a target for new anticancer drugs.

      Danson, Sarah; Ward, Timothy H; Butler, John; Ranson, Malcolm R; Paterson Institute for Cancer Research, Manchester, UK. sdanson@fsmail.net (2004-08)
      DT-diaphorase (DTD) is an obligate two-electron reductase which bioactivates chemotherapeutic quinones. DTD levels are elevated in a number of tumour types, including non-small cell lung carcinoma, colorectal carcinoma, liver cancers and breast carcinomas, when compared to the surrounding normal tissue. The differential in DTD between tumour and normal tissue should allow targeted activation of chemotherapeutic quinones in the tumour whilst minimising normal tissue toxicity. The prototypical bioreductive drug is Mitomycin C (MMC) which is widely used in clinical practice. However, MMC is actually a relatively poor substrate for DTD and its metabolism is pH-dependent. Other bioreductive drugs have failed because of poor solubility and inability to surpass other agents in use. RH1, a novel diaziridinylbenzoquinone, is a more efficient substrate for DTD. It has been demonstrated to have anti-tumour effects both in vitro and in vivo and demonstrates a relationship between DTD expression levels and drug response. RH1 has recently entered a phase I clinical trial in solid tumours under the auspices of Cancer Research UK. Recent work has demonstrated that DTD is present in the nucleus and is associated with both p53 and the heat shock protein, HSP-70. Furthermore, DTD is inducible by several non-toxic compounds and therefore much interest has focussed on increasing the differential in DTD levels between tumour and normal tissues.
    • Dual agent chemoprotection by retroviral co-expression of either MDR1 or MRP1 with the P140K mutant of O6-methylguanine-DNA-methyl transferase.

      Southgate, Thomas D; Garside, Elloise; Margison, Geoffrey P; Fairbairn, Leslie J; Cancer Research UK Gene Therapy Group, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Wilmslow Road, Manchester M20 4BX, UK. Tsouthgate@picr.man.ac.uk (2006-08)
      Tumour resistance to chemotherapeutic agents results in most chemotherapy being administered in a multi-agent fashion that is often associated with a high level of toxicity in highly proliferative tissues such as the haematopoietic compartment. Thus, whilst many genetic manipulation strategies aim to protect normal tissue against a single component of a multi-agent regime, it is clearly preferable to protect normal cells against all toxicities. In this study we have used retroviral gene transfer to achieve co-expression of either p-glycoprotein (MDR1) or multi-drug resistance-related protein 1 (MRP1) with the P140K mutant form of O6-methylguanine-DNA-methyl transferase (MGMT) which, unlike the wild-type protein, is insensitive to inactivation by tumour sensitisers such as O6-benzylguanine (O6-BeG) or PaTrin2. The combination of certain MDR1/MRP1 substrate drugs with O6-alkylating agents (against which MGMT confers resistance) is particularly myelotoxic. We show here that haematopoietic progenitors co-expressing mutant MGMT with an ABC-transporter exhibit resistance to combination chemotherapy in vitro. This combination of drug transporter and DNA repair function may provide an effective in vivo protection of the haematopoietic compartment during tumour ablation using combination chemotherapy.
    • Dual inhibition of STAT1 and STAT3 activation downregulates expression of PD-L1 in human breast cancer cells.

      Sasidharan Nair, V; Toor, S; Ali, B; Elkord, Eyad; Cancer Research Center , Qatar Biomedical Research Institute, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation , Doha , Qatar (2018-06)
      Breast cancer is the most commonly diagnosed cancer, and it is a leading cause of cancer-related deaths in females worldwide. Triple-negative breast cancer (TNBC) constitutes 15% of breast cancer and shows distinct metastasis profiles with poor prognosis. Strong PD-L1 expression has been observed in some tumors, supporting their escape from immune surveillance. Targeting PD-L1 could be a promising therapeutic approach in breast cancer patients. We investigated potential molecular mechanisms for constitutive expression of PD-L1 by inhibiting upstream STAT1 and STAT3 signals.
    • Dual repair modulation reverses Temozolomide resistance in vitro.

      Barvaux, Vincent A; Ranson, Malcolm R; Brown, Robert; McElhinney, R Stanley; McMurry, T Brian H; Margison, Geoffrey P; Paterson Institute for Cancer Research and Christie Hospital, Manchester, United Kingdom. (2004-02)
      Temozolomide is an alkylating agent that mediates its cytotoxic effects via O(6)-methylguanine (O(6)-meG) adducts in DNA and their recognition and processing by the postreplication mismatch repair system (MMR). O(6)-meG adducts can be repaired by the DNA repair protein O(6)-alkylguanine-DNA-alkyltransferase (MGMT), which therefore constitutes a major resistance mechanism to the drug. Resistance to Temozolomide can also be mediated by loss of MMR, which is frequently mediated by methylation of the hMLH1 gene promoter. Methylation of hMLH1 can be reversed by treatment of cells with 5-aza-2'-deoxycytidine, while the MGMT pseudosubstrate O(6)-(4-bromothenyl)guanine (PaTrin-2) can deplete MGMT activity. Using a drug-resistant cell line which expresses MGMT and has methylated hMLH1, we show that while either of these treatments can individually sensitize cells to Temozolomide, the combined treatment leads to substantially greater sensitization. The increased sensitization is not observed in matched MMR proficient cells.
    • A dual, non-redundant, role for LIF as a regulator of development and STAT3-mediated cell death in mammary gland.

      Kritikou, Ekaterini A; Sharkey, Andrew; Abell, Kathrine; Came, Paul J; Anderson, Elizabeth; Clarkson, Richard W E; Watson, Christine J; Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK. (2003-08)
      STAT3 is the key mediator of apoptosis in mammary gland. We demonstrate here that LIF is the physiological activator of STAT3, because in involuting mammary glands of Lif(-/-) mice, pSTAT3 is absent and the STAT3 target, C/EBPdelta, is not upregulated. Similar to Stat3 knockouts, Lif(-/-) mammary glands exhibit delayed involution, reduced apoptosis and elevated levels of p53. Significantly, Lif(-/-) glands display precocious development during pregnancy, when pSTAT3 is not normally detected. We show that pERK1/2 is significantly reduced in Lif(-/-) glands at this time, suggesting that at this stage LIF mediates its effects through pERK1/2. Inhibition of LIF-mediated ERK1/2 phosphorylation potentiates the proapoptotic effects of STAT3. LIF therefore signals alternately through ERK1/2, then STAT3, to regulate mammary growth and apoptosis.