School of Cancer and Imaging Sciences
In 2007 the School of Medicine was restructured to form four Research Schools and the Manchester Medical School.The Research School of Cancer and Imaging Sciences works closely with partner trusts, such as The Christie, for effective research in biomedical sciences. This collection contains items published from 2008 onwards
Collections in this community
Recent Submissions
-
Antimigratory and antimetastatic effect of heparin-derived 4-18 unit oligosaccharides in a preclinical human melanoma metastasis model.Heparin and its derivatives have been shown to inhibit angiogenesis and metastasis formation. Accordingly, we investigated the effect of heparin fragments containing 4 to 22 monomers on human melanoma cell proliferation, migration and invasion in vitro as well as on the in vivo metastatic potential in a SCID mouse model. Only oligosaccharide dp18 had significant inhibitory effect on cell proliferation. In contrast, cell migration was inhibited by all oligosaccharides studied except dp8 and dp22. Anti-CD44v3 antibody stimulated cell migration and invasion, and this effect could be attenuated by oligosaccharides dp4 and dp18. These fragments also inhibited the catalytic activity of myosin light chain phosphatase as well. Moreover, oligosaccharides dp4 and dp18 reduced the number of lung colonies formed in SCID mice intravenously injected with human melanoma cells, while dp22 proved to be ineffective in this respect. These studies revealed that fragments of heparin have an antimigratory and antimetastatic potential. These fragments lack the haemostatic effect of heparin, suggesting that they are potential specific antimetastatic agents in anticancer therapy.
-
Adding more content to screening: reactivation of FOXO as a therapeutic strategy.The discovery of novel targets that can be pharmacologically exploited to lead to a better disease outcome has long been an aim of biomedical research. At present, the technology and robotisation available have pushed the search for novel molecules to a high-throughput screening (HTS) context, making it possible to screen several hundreds of compounds or genes in a single day. High-content screenings (HCS) have added a refined complexity to the screening processes, as the information drawn from an image- based assay is more complete than the monoparametric readouts obtained in classical HTS assays. Here, we review the development of HCS platforms to identify molecules influencing FOXO nuclear relocation and activation as pharmacological targets, their applicability and the future directions of the screening field.
-
Ectopic HOXB4 overcomes the inhibitory effect of tumor necrosis factor-{alpha} on Fanconi anemia hematopoietic stem and progenitor cells.Ectopic delivery of HOXB4 elicits the expansion of engrafting hematopoietic stem cells (HSCs). We hypothesized that inhibition of tumor necrosis factor-alpha (TNF-alpha) signaling may be central to the self-renewal signature of HOXB4. Because HSCs derived from Fanconi anemia (FA) knockout mice are hypersensitive to TNF-alpha, we studied Fancc(-/-) HSCs to determine the physiologic effects of HOXB4 on TNF-alpha sensitivity and the relationship of these effects to the engraftment defect of FA HSCs. Overexpression of HOXB4 reversed the in vitro hypersensitivity to TNF-alpha of Fancc(-/-) HSCs and progenitors (P) and partially rescued the engraftment defect of these cells. Coexpression of HOXB4 and the correcting FA-C protein resulted in full correction compared with wild-type (WT) HSCs. Ectopic expression of HOXB4 resulted in a reduction in both apoptosis and reactive oxygen species in Fancc(-/-) but not WT HSC/P. HOXB4 overexpression was also associated with a significant reduction in surface expression of TNF-alpha receptors on Fancc(-/-) HSC/P. Finally, enhanced engraftment was seen even when HOXB4 was expressed in a time-limited fashion during in vivo reconstitution. Thus, the HOXB4 engraftment signature may be related to its effects on TNF-alpha signaling, and this pathway may be a molecular target for timed pharmacologic manipulation of HSC during reconstitution.
-
Methods comparison for high-resolution transcriptional analysis of archival material on Affymetrix Plus 2.0 and Exon 1.0 microarrays.Microarray gene expression profiling of formalin-fixed paraffin-embedded (FFPE) tissues is a new and evolving technique. This report compares transcript detection rates on Affymetrix U133 Plus 2.0 and Human Exon 1.0 ST GeneChips across several RNA extraction and target labeling protocols, using routinely collected archival FFPE samples. All RNA extraction protocols tested (Ambion-Optimum, Ambion-RecoverAll, and Qiagen-RNeasy FFPE) provided extracts suitable for microarray hybridization. Compared with Affymetrix One-Cycle labeled extracts, NuGEN system protocols utilizing oligo(dT) and random hexamer primers, and cDNA target preparations instead of cRNA, achieved percent present rates up to 55% on Plus 2.0 arrays. Based on two paired-sample analyses, at 90% specificity this equalled an average 30 percentage-point increase (from 50% to 80%) in FFPE transcript sensitivity relative to fresh frozen tissues, which we have assumed to have 100% sensitivity and specificity. The high content of Exon arrays, with multiple probe sets per exon, improved FFPE sensitivity to 92% at 96% specificity, corresponding to an absolute increase of ~600 genes over Plus 2.0 arrays. While larger series are needed to confirm high correspondence between fresh-frozen and FFPE expression patterns, these data suggest that both Plus 2.0 and Exon arrays are suitable platforms for FFPE microarray expression analyses.
-
The impact of primary tumour origins in patients with advanced oesophageal, oesophago-gastric junction and gastric adenocarcinoma--individual patient data from 1775 patients in four randomised controlled trials.BACKGROUND: It is unclear if differential chemotherapy effects exist on overall survival (OS), response rate (RR) and toxicity depending on primary tumour origin [oesophageal versus oesophago-gastric junction (OGJ) versus gastric adenocarcinoma]. PATIENTS AND METHODS: A total of 2110 patients were enrolled in four randomised controlled trials (RCTs) assessing fluoropyrimidine +/- platinum-based chemotherapy. This analysis used individual patient data and restricted to patients with adenocarcinoma who received one or more dose of chemotherapy. Gastric origin was the control in comparisons of tumour origin. RESULTS: Of the 2110 patients randomised, 1775 (84%) patients had adenocarcinoma with oesophageal (n = 485), OGJ (n = 457) and gastric (n = 833) origins. The median OS was 9.5 months in oesophageal, 9.3 months in OGJ and 8.7 months in gastric cancer (P = 0.68). RR was 44.1% in oesophageal, 41.1% in OGJ and 35.6% in gastric cancers (P = 0.11 and 0.27, respectively, compared with gastric cancer on multivariate analysis). Toxicity composite end point occurred in 46%, 47% and 45% in oesophageal, OGJ and gastric cancers, respectively (P = 0.85 and 0.62 compared with gastric). CONCLUSIONS: In our large multicentre RCT dataset, no significant differences were demonstrated on multivariate analyses in OS, RR and toxic effects among patients with advanced oesophageal, OGJ and gastric adenocarcinoma. Future RCTs should not exclude oesophageal adenocarcinoma.
-
Predicting the myelotoxicity of chemotherapy: the use of pretreatment O6-methylguanine-DNA methyltransferase determination in peripheral blood mononuclear cells.To assess the value of pretreatment O-methylguanine-DNA methyltransferase (MGMT) expression in peripheral blood mononuclear cells (PBMCs) in predicting haematological toxicity with O-alkylating agent chemotherapy, we explored this relationship retrospectively in melanoma patients. Ninety-three patients treated with temozolomide or dacarbazine in four clinical trials were assessed, and a model of the interaction between MGMT expression and haematological toxicity was constructed. Nadir white-cell and platelet counts were related to, and hence could be predicted from, pretreatment MGMT. Leucopenia and thrombocytopenia were more prevalent amongst patients with low pretreatment MGMT, according to the highest grades of toxicity experienced and/or the dose intensity patients could sustain. Addition of interferon to chemotherapy or compression of the temozolomide schedule increased the toxicity. The model also predicts significant myelotoxicity where PBMC MGMT is inactivated, consistent with the experience in the clinic with lomeguatrib and O-benzylguanine. Determination of MGMT in PBMC can identify patients at greatest risk of toxicity or who are suitable for dose intensification.
-
Monoclonal antibodies directed to CD20 and HLA-DR can elicit homotypic adhesion followed by lysosome-mediated cell death in human lymphoma and leukemia cells.mAbs are becoming increasingly utilized in the treatment of lymphoid disorders. Although Fc-FcgammaR interactions are thought to account for much of their therapeutic effect, this does not explain why certain mAb specificities are more potent than others. An additional effector mechanism underlying the action of some mAbs is the direct induction of cell death. Previously, we demonstrated that certain CD20-specific mAbs (which we termed type II mAbs) evoke a nonapoptotic mode of cell death that appears to be linked with the induction of homotypic adhesion. Here, we reveal that peripheral relocalization of actin is critical for the adhesion and cell death induced by both the type II CD20-specific mAb tositumomab and an HLA-DR-specific mAb in both human lymphoma cell lines and primary chronic lymphocytic leukemia cells. The cell death elicited was rapid, nonapoptotic, nonautophagic, and dependent on the integrity of plasma membrane cholesterol and activation of the V-type ATPase. This cytoplasmic cell death involved lysosomes, which swelled and then dispersed their contents, including cathepsin B, into the cytoplasm and surrounding environment. The resulting loss of plasma membrane integrity occurred independently of caspases and was not controlled by Bcl-2. These experiments provide what we believe to be new insights into the mechanisms by which 2 clinically relevant mAbs elicit cell death and show that this homotypic adhesion-related cell death occurs through a lysosome-dependent pathway.
-
Frequency of human T regulatory cells in peripheral blood is significantly reduced by cryopreservation.Cryopreservation of peripheral blood mononuclear cells (PBMC) is essential for many clinical and research assays. Some studies reported consistent changes in PBMC phenotype following cryopreservation. We hypothesized that PBMC freezing may have a negative impact on estimation of the frequency of T regulatory cell (Treg). Treg levels were measured in 6 fresh PBMC samples isolated from 6 healthy donors and these levels were re-measured after freezing for three weeks. Herein, we report a significant reduction in Treg frequency in all samples following cryopreservation.
-
Flipping of alkylated DNA damage bridges base and nucleotide excision repair.Alkyltransferase-like proteins (ATLs) share functional motifs with the cancer chemotherapy target O(6)-alkylguanine-DNA alkyltransferase (AGT) and paradoxically protect cells from the biological effects of DNA alkylation damage, despite lacking the reactive cysteine and alkyltransferase activity of AGT. Here we determine Schizosaccharomyces pombe ATL structures without and with damaged DNA containing the endogenous lesion O(6)-methylguanine or cigarette-smoke-derived O(6)-4-(3-pyridyl)-4-oxobutylguanine. These results reveal non-enzymatic DNA nucleotide flipping plus increased DNA distortion and binding pocket size compared to AGT. Our analysis of lesion-binding site conservation identifies new ATLs in sea anemone and ancestral archaea, indicating that ATL interactions are ancestral to present-day repair pathways in all domains of life. Genetic connections to mammalian XPG (also known as ERCC5) and ERCC1 in S. pombe homologues Rad13 and Swi10 and biochemical interactions with Escherichia coli UvrA and UvrC combined with structural results reveal that ATLs sculpt alkylated DNA to create a genetic and structural intersection of base damage processing with nucleotide excision repair.
-
Spectral discrimination of live prostate and bladder cancer cell lines using Raman optical tweezers.An investigation into the use of Raman optical tweezers to study urological cell lines is reported, with the ultimate aim of determining the presence of malignant CaP cells in urine and peripheral fluids. To this end, we trapped and analyzed live CaP cells (PC-3) and bladder cells (MGH-U1), because both prostate and bladder cells are likely to be present in urine. The laser excitation wavelength of 514.5 nm was used, with Raman light collected both in back- and forward-scattering geometric configurations. For the backscattering configuration the same laser was used for trapping and excitation, while for forward scattering a 1064 nm laser provided the trapping beam. Analysis of cell-diameter distributions for cells analyzed suggested normal distribution of cell sizes, indicating an unbiased cell-selection criterion. Principal components analysis afforded discrimination of MGH-U1 and PC-3 spectra collected in either configuration, demonstrating that it is possible to trap, analyze, and differentiate PC-3 from MGH-U1 cells using a 514.5 nm laser. By loading plot analysis, possible biomolecules responsible for discrimination in both configurations were determined. Finally, the effect of cell size on discrimination was investigated, with results indicating that separation is based predominantly on cell type rather than cell size.
-
New therapeutic agents in ovarian cancer.PURPOSE OF REVIEW: Despite advances in management over recent years, epithelial ovarian cancer remains the most lethal gynaecological malignancy. Methods of early detection, as well as improved therapeutic options, are urgently needed. RECENT FINDINGS: Currently, a number of targeted therapies, including vascular endothelial growth factor inhibitors, poly-ADP-ribose polymerase inhibitors and folate receptor inhibitors look promising in this arena and this article will review a number of these drugs and the evidence pertaining to their use. SUMMARY: Much further research is required to define if, when and how best to integrate these novel therapies, and also to define associated biomarkers that predict toxicity and select patients most likely to derive benefit. Individualized therapy is not an impossible dream, but there is still a long way to go.
-
SRC-induced disassembly of adherens junctions requires localized phosphorylation and degradation of the rac activator tiam1.The Rac activator Tiam1 is required for adherens junction (AJ) maintenance, and its depletion results in AJ disassembly. Conversely, the oncoprotein Src potently induces AJ disassembly and epithelial-mesenchymal transition (EMT). Here, we show that Tiam1 is phosphorylated on Y384 by Src. This occurs predominantly at AJs, is required for Src-induced AJ disassembly and cell migration, and creates a docking site on Tiam1 for Grb2. We find that Tiam1 is associated with ERK. Following recruitment of the Grb2-Sos1 complex, ERK becomes activated and triggers the localized degradation of Tiam1 at AJs, likely involving calpain proteases. Furthermore, we demonstrate that, in human tumors, Y384 phosphorylation positively correlates with Src activity, and total Tiam1 levels are inversely correlated. Thus, our data implicate Tiam1 phosphorylation and consequent degradation in Src-mediated EMT and resultant cell motility and establish a paradigm for regulating local concentrations of Rho-GEFs.
-
Hypoxia response element-driven cytosine deaminase/5-fluorocytosine gene therapy system: a highly effective approach to overcome the dynamics of tumour hypoxia and enhance the radiosensitivity of prostate cancer cells in vitro.BACKGROUND: We proposed to exploit hypoxia-inducible factor (HIF)-1alpha overexpression in prostate tumours and use this transcriptional machinery to control the expression of the suicide gene cytosine deaminase (CD) through binding of HIF-1alpha to arrangements of hypoxia response elements. CD is a prodrug activation enzyme, which converts inactive 5-fluorocytosine to active 5-fluorouracil (5-FU), allowing selective killing of vector containing cells. METHODS: We developed a pair of vectors, containing either five or eight copies of the hypoxia response element (HRE) isolated from the vascular endothelial growth factor (pH5VCD) or glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (pH8GCD) gene, respectively. The kinetics of the hypoxic induction of the vectors and sensitization effects were evaluated in 22Rv1 and DU145 cells in vitro. RESULTS: The CD protein as selectively detected in lysates of transiently transfected 22Rv1 and DU145 cells following hypoxic exposure. This is the first evidence of GAPDH HREs being used to control a suicide gene therapy strategy. Detectable CD levels were sustained upon reoxygenation and prolonged hypoxic exposures. Hypoxia-induced chemoresistance to 5-FU was overcome in both cell lines treated with this suicide gene therapy approach. Hypoxic transfectants were sensitized to prodrug concentrations that were ten-fold lower than those that are clinically relevant. Moreover, the surviving fraction of reoxygenated transfectants could be further reduced with the concomitant delivery of clinically relevant single radiation doses. CONCLUSIONS: This strategy thus has the potential to sensitize the hypoxic compartment of prostate tumours and improve the outcome of current therapies.
-
The binding properties of minimal oligosaccharides reveal a common heparan sulfate/dermatan sulfate-binding site in hepatocyte growth factor/scatter factor that can accommodate a wide variety of sulfation patterns.Heparan sulfate (HS)/heparin and dermatan sulfate (DS) both bind with high affinity to hepatocyte growth factor/scatter factor (HGF/SF) and function as necessary co-factors in vitro. How both these two structurally distinct glycosaminoglycans (GAGs) are recognized has remained unclear. We have now reconciled this issue using a panel of minimal tri- and tetrasaccharide sequences of variable but well defined sulfation patterns in combination with further development of the gel mobility shift assay to allow simultaneous comparisons of relative protein affinities/selectivities for different oligosaccharides. From this approach it would seem that a minimum binding sequence is a disulfated trisaccharide comprised of an internal iduronate flanked by monosulfated hexosamine residues and that additional sulfation further enhances affinity. However, the similarity in recognition of HS/heparin and DS seems to arise primarily from a lack of any apparent positional requirement for sulfation. Thus, isomers of HS/heparin tetrasaccharides containing only two sulfates irrespective of whether they are purely N-, 2-O-, or 6-O-sulfates bind with equivalent apparent affinity as a disulfated DS tetrasaccharide. In addition, the NMR chemical shifts induced in NK1 (the truncated variant of HGF/SF comprised of the N-terminal and first Kringle domains) by titration with either heparin or DS oligosaccharides strongly indicate that both bind to essentially the same site. Together, these observations reveal an unexpected degree of flexibility in the GAG-HGF/SF interface, allowing a single binding site in the protein to accommodate iduronate-containing sequences of variable sulfation pattern and/or density from different GAGs.