Spelling suggestions: "subject:"aancer therapy"" "subject:"7cancer therapy""
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<b>FGFR1 REGULATION IN BREAST CANCER: LIGAND-DEPENDENT ACTIVATION AND NOVEL TARGETING STRATEGIES</b>Muhammad H Safdar (19180555) 20 July 2024 (has links)
<p dir="ltr">Metastatic breast cancer (MBC) and consequent dormancy present a significant clinical challenge due to recurrence and relapse. It is thus pivotal to understand the mechanisms which can reawaken the dormant cancer cells into a proliferative phenotype, and to develop effective therapeutic strategies to eradicate the minimal residual disease. Fibroblast Growth Factor Receptor 1 (FGFR1) is a receptor tyrosine kinase (RTK) which is amplified in MBC and plays a key role in cancer cell plasticity. Interestingly, while dormant cancer cells also exhibit high FGFR1 expression levels; still, mere FGFR1 alone is insufficient to drive proliferation without FGF2 ligand induced receptor activation. In accordance with previous data, we report elevated levels of FGF2 in serum of mice with diet induced obesity (DIO), thereby indicating a potential link between obesity and dormancy breakage. We demonstrate that serum from obese animals, exogenous FGF2 stimulation, or constitutive stimulation through autocrine and paracrine FGF2 is sufficient to induce proliferation and drive pulmonary outgrowth of the dormant D2OR model. Additionally, blockade of FGFR signaling via FGFR kinase inhibitors prevented ligand induced outgrowth of the D2OR model. Importantly, FGFR1 overexpression in normal mammary epithelial cells also requires FGF2 signaling to induce transformation suggesting that mere FGFR1 amplification alone is not a driving event.</p><p dir="ltr">Despite elevated FGFR1 expression levels in dormant and metastatic breast cancer, FGFR kinase inhibitors have been unsuccessful in inducing a significant therapeutic response in FGFR1-amplified setting, potentially due to the inability of targeting the kinase-independent functions of FGFR1. In our study, we explored the use of G-quadruplex (G4) stabilizers as epigenetic therapeutics to limit FGFR1 expression, thus targeting both kinase-dependent and independent functions of the receptor. Our findings demonstrate that, in contrast to the FDA approved FGFR-kinase inhibitors, G4 stabilizers significantly reduce the viability of dormant cells in 3D culture models. Additionally, the G4 stabilizers effectively suppressed the expression of other oncogenes such as PDGFR and MYC, which is advantageous given the heterogeneous nature of dormant and MBC cells. The results from our findings suggest that FGF2:FGFR1 signaling acts as a key molecular mechanism in modulating dormancy and breast cancer progression. Additionally, G4 stabilizers hold promise as a novel therapeutic approach to target and eliminate dormant breast cancer cells, potentially reducing the risk of relapse and improving long-term patient outcomes.</p>
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Engineering of Polyamidoamine Dendrimers for Cancer TherapyXu, Leyuan 01 January 2015 (has links)
Dendrimers are a class of polymers with a highly branched, three-dimensional architecture comprised of an initiator core, several interior layers of repeating units, and multiple active surface terminal groups. Dendrimers have been recognized as the most versatile compositionally and structurally controlled nanoscale building blocks for drug and gene delivery. Polyamidoamine (PAMAM) dendrimers have been most investigated because of their unique structures and properties. Polycationic PAMAM dendrimers form compacted polyplexes with nucleic acids at physiological pH, holding great potential for gene delivery.
Folate receptor (FRα) is expressed at very low levels in normal tissues but expressed at high levels in cancers in order to meet the folate demand of rapidly dividing cells under low folate conditions. Our primary aim was to investigate folic acid (FA)-conjugated PAMAM dendrimer generation 4 (G4) conjugates (G4-FA) for targeted gene delivery. The in vitro cellular uptake and transfection efficiency of G4-FA conjugates and G4-FA/DNA polyplexes were investigated in Chapter 4. It was found the cellular uptake of G4-FA conjugates and G4-FA/DNA polyplexes was in a FR-dependent manner. Free FA competitively inhibited the cellular uptake of G4-FA conjugates and G4-FA/DNA polyplexes. G4-FA/DNA polyplexes were preferentially taken up by FR-positive HN12 cells but not FR-negative U87 cells. In contrast, the cellular uptake of G4 dendrimers and G4/DNA polyplexes was non-selective via absorptive endocytosis. G4-FA conjugates significantly enhanced cytocompatibility and transfection efficiency compared to G4 dendrimers. This work demonstrates that G4-FA conjugates allow FR-targeted gene delivery, reduce cytotoxicity, and enhance gene transfection efficiency.
The in vivo biodistribution of G4-FA conjugates and anticancer efficacy of G4-FA/siRNA polyplexes were investigated in Chapter 5. Vascular endothelial growth factor A (VEGFA) is one of the major regulators of angiogenesis, essential for the tumor development. It was found G4-FA/siVEGFA polyplexes significantly knocked down VEGFA mRNA expression and protein release in HN12 cells. In the HN12 tumor-bearing nude mice, G4-FA conjugates were preferentially taken up by the tumor and retained in the tumor for at least 21 days following intratumoral (i.t.) administration. Two-dose i.t. administration of G4-FA/siVEGFA polyplexes significantly inhibited tumor growth by lowering tumor angiogenesis. In contrast, two-dose i.t. administration of G4/siVEGFA polyplexes caused severe skin lesion, presumably as a result of local toxicity. Taken together, this work shows great potential for the use of G4-FA conjugates in targeted gene delivery and cancer gene therapy.
We also explored polyanionic PAMAM dendrimer G4.5 as the underlying carrier to carry camptothecin (CPT) for glioblastoma multiforme therapyin Chapter 6. "Click" chemistry was applied to improve polymer-drug coupling reaction efficiency. The CPT-conjugate displayed a dose-dependent toxicity with an IC50 of 5 μM, a 185-fold increase relative to free CPT, presumably as a result of slow release. The conjugated CPT resulted in G2/M arrest and cell death while the dendrimer itself had little to no toxicity. This work indicates highly efficient "click" chemistry allows for the synthesis of multifunctional dendrimers for sustained drug delivery.
Immobilizing PAMAM dendrimers to the cell surface may represent an innovative method of enhancing cell surface loading capacity to deliver therapeutic and imaging agents. In Chapter 7, macrophage RAW264.7 (RAW) was hybridized with PAMAM dendrimer G4.0 (DEN) on the basis of bioorthogonal chemistry. Efficient and selective cell surface immobilization of dendrimers was confirmed by confocal microscopy. It was found the viability and motility of RAW-DEN hybrids remained the same as untreated RAW cells. Furthermore, azido sugar and dendrimer treatment showed no effect on intracellular AKT, p38, and NFκB (p65) signaling, indicating that the hybridization process neither induced cell stress response nor altered normal signaling. This work shows the feasibility of applying bioorthogonal chemistry to create cell-nanoparticle hybrids and demonstrates the noninvasiveness of this cell surface engineering approach.
In summary, these studies indicate surface-modification of PAMAM dendrimer G4 with FA can effectively target at FR-positive cells and subsequently enhance in vitro transfection efficiency and in vivo gene delivery. G4-FA conjugates may serve as a versatile targeted gene delivery carrier potentially for cancer gene therapy. PAMAM dendrimers G4.5 may serve as a drug delivery carrier for the controlled release of chemotherapeutics. The immune cell-dendrimer hybrids via bioorthogonal chemistry may serve as an innovative drug and gene delivery carrier potentially for cancer chemotherapy. Taken together, engineering of PAMAM dendrimers may advance anticancer drug and gene delivery.
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Monte Carlo particle transport codes for ion beam therapy treatment planning : Validation, development and applicationsBöhlen, Till Tobias January 2012 (has links)
External radiotherapy with proton and ion beams needs accurate tools for the dosimetric characterization of treatment fields. Monte Carlo (MC) particle transport codes, such as FLUKA and GEANT4, can be a valuable method to increase accuracy of dose calculations and to support various aspects of ion beam therapy (IBT), such as treatment planning and monitoring. One of the prerequisites for such applications is however that the MC codes are able to model reliably and accurately the relevant physics processes. As a first focus of this thesis work, physics models of MC codes with importance for IBT are developed and validated with experimental data. As a result suitable models and code configurations for applications in IBT are established. The accuracy of FLUKA and GEANT4 in describing nuclear fragmentation processes and the production of secondary charged nuclear fragments is investigated for carbon ion therapy. As a complementary approach to evaluate the capability of FLUKA to describe the characteristics of mixed radiation fields created by ion beams, simulated microdosimetric quantities are compared with experimental data. The correct description of microdosimetric quantities is also important when they are used to predict values of relative biological effectiveness (RBE). Furthermore, two models describing Compton scattering and the acollinearity of two-quanta positron annihilation at rest in media were developed, validated and integrated in FLUKA. The detailed description of these processes is important for an accurate simulation of positron emission tomography (PET) and prompt-γ imaging. Both techniques are candidates to be used in clinical routine to monitor dose administration during cancer treatments with IBT. The second objective of this thesis is to contribute to the development of a MC-based treatment planning tool for protons and ions with atomic number Z ≤ 8 using FLUKA. In contrast to previous clinical FLUKA-based MC implementations for IBT which only re-calculate a given treatment plan, the developed prototype features inverse optimization of absorbed dose and RBE-weighted dose for single fields and simultaneous multiple-field optimization for realistic treatment conditions. In a study using this newly-developed tool, the robustness of IBT treatment fields to uncertainties in the prediction of RBE values is investigated, while comparing different optimization strategies. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Submitted. Paper 6: Manuscript.</p>
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Design Of Intelligent Nanoparticles For Use In Controlled ReleaseBanu, Bayyurt 01 March 2009 (has links) (PDF)
The aim of this project was to design an intelligent controlled release system
based on thermoresponsive nanoparticles for cancer therapy and to evaluate
the efficiencies of these systems with in vitro cell culture. Poly(Nisopropylacrylamide),
an important thermoresponsive polymer, was selected
for this study to prepare the responsive nanoparticles. This polymer has an
lower critical solution temperature (LCST) of 32 oC, below which it is
hydrophilic and above this temperature, it shows hydrophobic behavior.
Controlling drug release with this property was the objective of this study.
Nanoparticles were prepared by nanoprecipitation method. By using different
solvent:non-solvent ratios and polymer concentrations, different samples
were prepared. The particle size was decreased when solvent:non-solvent
ratio was increased and polymer concentration was decreased. This was found
to be related with the solution viscosity.
Nanoparticles prepared from polymers prepared with different initiatoraccelarator
amounts had significantly different sizes and release rates, and
additionally the size of particles prepared from polymers with various
crosslinker amounts were decreased with increased croslinker amount.
In situ release experiments were performed both below and above polymer& / #8216 / s
LCST degree. Uncrosslinked nanoparticles demonstrated higher release rate of
Celecoxib above LCST. However, there was no significant difference with the
crosslinked nanoparticles.
Crosslinked and uncrosslinked nanoparticles were tested on Saos-2 cells to
assess their toxicity. Both Celecoxib loaded and free crosslinked particles were
found to be cytotoxic. Uncrosslinked nanoparticles showed an increased
toxicity upon loading with the bioactive agent, Celecoxib. In conclusion,
uncrosslinked particles would be a proper drug carrier for cancer therapy with
enhanced drug loading.
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Single wall carbon nanotube based nanoparticles and hydrogel for cancer therapyLiu, Shuhan Jr January 2014 (has links)
Nowadays, cancer treatment and tissue regeneration have attracted large amount of attention. Single Wall Carbon Nanotubes (SWNT) possess large surface area and outstanding optical and electrical performance, making it a promising component in cancer therapy and tissue reengineering systems. In this study, four disease treating systems based on SWNT are developed. They are pH-sensitive poly(ethylene glycol)-doxorubicin(PEG-DOX)@SWNT drug release system, temperature sensitive SWNT hydrogel, SWNT based biocompatible magnetic hydrogel and biocompatible SWNT-gelatin-F127-cysteamine hydrogel for tissue engineering. The successfully synthesized target compounds are characterized by FTIR. The in vitro release of drugs from the drug release systems is evaluated upon changes of pH values and the laser scanning. The effect of cancer treatment systems on specific kind of cells are examined by confocal laser scanning microscopy (CLSM). The results indicate that all of the four systems show great potential in the biomedical applications especially in disease therapy applications.
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Single-cell Raman spectroscopy of irradiated tumour cellsMatthews, Quinn 30 September 2011 (has links)
This work describes the development and application of a novel combination of single-cell Raman spectroscopy (RS), automated data processing, and principal component analysis (PCA) for investigating radiation induced biochemical responses in human tumour cells. The developed techniques are first validated for the analysis of large data sets (~200 spectra) obtained from single cells. The effectiveness and robustness of the automated data processing methods is demonstrated, and potential pitfalls that may arise during the implementation of such methods are identified. The techniques are first applied to investigate the inherent sources of spectral variability between single cells of a human prostate tumour cell line (DU145) cultured {\it in vitro}. PCA is used to identify spectral differences that correlate with cell cycle progression and the changing confluency of a cell culture during the first 3-4 days after sub-culturing. Spectral variability arising from cell cycle progression is (i) expressed as varying intensities of protein and nucleic acid features relative to lipid features, (ii) well correlated with known biochemical changes in cells as they progress through the cell cycle, and (iii) shown to be the most significant source of inherent spectral variability between cells. This characterization provides a foundation for interpreting spectral variability in subsequent studies.
The techniques are then applied to study the effects of ionizing radiation on human tumour cells. DU145 cells are cultured in vitro and irradiated to doses between 15 and 50 Gy with single fractions of 6 MV photons from a medical linear accelerator. Raman spectra are acquired from irradiated and unirradiated cells, up to 5 days post-irradiation. PCA is used to distinguish radiation induced spectral changes from inherent sources of spectral variability, such as those arising from cell cycle. Radiation induced spectral changes are found to correlate with both the irradiated dose and the incubation time post-irradiation, and to arise from biochemical differences in lipids, nucleic acids, amino acids, and conformational protein structures between irradiated and unirradiated cells. This study is the first use of RS to observe radiation induced biochemical effects in single cells, and is the first use of vibrational spectroscopy to observe such effects independent from cell cycle or cell death related processes.
The same methods are then applied to a panel of human tumour cell lines, derived from prostate (DU145, PC3, LNCaP and PacMet), breast (MDA-MB-231 and MCF7) and lung (H460), which vary by p53 gene status and intrinsic radiosensitivity. One radiation induced PCA component is detected for each cell line by statistically significant changes in the PCA score distributions for irradiated samples, as compared to unirradiated samples, in the first 24 to 72 hours post-irradiation. These RS response signatures arise from radiation induced changes in cellular concentrations of aromatic amino acids, conformational protein structures, and certain nucleic acid and lipid functional groups. Correlation analysis between the radiation induced PCA components separates the cell lines into three unique RS response categories: R1 (H460, MCF7 and PacMet), R2 (MDA-MB-231 and PC3), and R3 (DU145 and LNCaP). These RS categories partially segregate according to radiosensitivity; the R1 and R2 cell lines are radioresistant and the R3 cell lines are radiosensitive (PacMet radiosensitivity (R1) unknown). The R1 and R2 cell lines further segregate according to p53 gene status, corroborated by cell cycle analysis post-irradiation. Preliminary results obtained from a mouse prostate tumour cell line (TRAMP-C2), irradiated both in vitro and in vivo, indicate that RS signatures of radiation response may also be detectable from tumour cells obtained from an in vivo system during radiation therapy treatment. These results indicate the potential for future RS studies designed to investigate, monitor, or predict radiation response. / Graduate
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The impact of nanoconjugation to EGF-induced apoptosisWu, Linxi 16 February 2016 (has links)
Engineered nanoparticles provide potential opportunities for improving current drug delivery, bioimaging and biosensing modalities. In many cases, a ligand, such as a protein, peptide or nucleic acids, is attached to the nanoparticles surface to serve as a targeting group. However, the nanoconjugation (i.e. covalently bound molecules to a nanocarrier) is not an innocuous reaction. It can change the binding affinity and interfere with the intracellular trafficking of the tethered species. The understanding of this influence to the tethered species is still lacking. Therefore, the main objective of this thesis is to investigate the effect of nanoconjugation to the biological identity of the tethered biomolecules, in terms of cellular uptake, intracellular trafficking and the ultimate biological outcomes.
The Epidermal Growth Factor Receptor (EGFR) is a tyrosine kinase that regulates cell proliferation and can cause cancer if dysregulated. Continuous treatment with high doses of EGF can induce apoptosis, in EGFR overexpressing cell lines. In this thesis, Epidermal Growth Factor (EGF) was chosen as the object of investigation. Covalent attachment of EGF to gold nanoparticles (NP-EGF) was found to enhance apoptosis in EGFR overexpressing cell lines (A431, MDA-MB-468) and it is sufficient to induce apoptosis in cell lines exhibiting EGFR expression at physiological levels (HeLa). NP-EGF accumulation through the endosomal pathway was also investigated to assess the impact of nanoconjugation on the spatio-temporal distribution of NP-EGF as potential origin for the observed enhancement of apoptosis. Two orthogonal experimental approaches were applied: (1) isolation of NP-EGF containing endosomes by taking advantage of the increased density of endosomes associated with the uptake of Au NPs; (2) correlated darkfield/fluorescence imaging to map the spatial distribution of NP-EGF in endosomes as a function of time. The studies reveal that nanoconjugation prolongs the dwelling time of phosphorylated receptors in the early endosomes and that the retention of activated EGFR in the early endosomes is accompanied by an EGF mediated apoptosis at effective concentrations that do not induce apoptosis in the case of the free EGF.
Investigating the nanoconjugation-enhanced EGF-induced apoptosis improves the current understanding of cell-nanomatieral interactions and provides new opportunities for overcoming apoptosis evasion by cancer cells. / 2017-01-01T00:00:00Z
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Mechanismy imunitní odpovědi při léčbě rakoviny kotvením ligandů fagocytárních receptorů na povrch nádorových buněk / Mechanisms of the immune response during the cancer treatment with ligands of phagocytic receptors anchored to the surface of malignant cellsAUEROVÁ, Marie January 2014 (has links)
The aim of this thesis was to obtain some insights into mechanisms by which the immune system affects melanoma cells after anchoring agonists of phagocytic receptors (laminarin and f-MLF) to their surface. To verify the hypothesis that innate immune system plays a critical role, in vivo experiments were performed on SCID mice. To elucidate the importance of CR3, CD11b-deficient mice were used. In in vitro experiments production of inflammatory cytokines in tumor tissue was examined as well as the release of myeloperoxidase from neutrophil granules after incubation with malignant cells.
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Cancer Stem/Progenitor Cell Active Compound 8-Quinolinol in Combination With Paclitaxel Achieves an Improved Cure of Breast Cancer in the Mouse ModelZhou, Jiangbing, Zhang, Hao, Gu, Peihua, Margolick, Joseph B., Yin, Deling, Zhang, Ying 01 May 2009 (has links)
Increasing evidence suggests that breast cancer is caused by cancer stem cells and the cure of breast cancer requires eradication of breast cancer stem cells. In this study, we established and characterized a sphere culture model derived from side population cells from the human breast cancer cell line MCF7. The sphere culture could be maintained long term and was enriched in cells expressing known breast cancer stem cell marker CD44+CD24 -. These sphere cells showed higher colony formation ability in vitro and higher tumorigenicity in vivo than MCF7 cells, suggesting the enrichment of breast cancer stem/progenitor cells. To identify compounds that preferentially inhibit the sphere cells, we performed a compound library screening. Two lead compounds, NSC24076 and NSC125034 and an analog of NSC125034, 8-quinolinol (8Q), were identified as having preferential activity against the sphere cells. 8Q showed some antitumor activity alone but had much better therapeutic effect and relapse prevention when combined with paclitaxel than either 8Q or paclitaxel alone in both MCF7 and MDA-MB-435 xenograft models. We propose that compounds selectively targeting cancer stem/progenitor cells when combined with standard chemotherapy drugs may produce an improved treatment of cancer without significant relapse.
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Therapeutic potential of targeting the oncofetal antigen ROR1Behzadi, Fernanda 11 June 2019 (has links)
The increasing prevalence of drug resistant cancers to conventional therapies remains a major challenge in oncology, emphasizing the need for further research and treatment development. The receptor tyrosine kinase-like orphan receptor 1 (ROR1) presents as a particularly suitable target for cancer therapy, as this type I transmembrane protein is expressed during embryogenesis and up-regulated in various solid and hematological malignancies, but generally repressed in normal adult tissues. A growing cancer literature has established ROR1 as a contributor to cell metastasis and a survival factor for malignant cells, suggesting the therapeutic potential in targeting ROR1 for cancer therapy. The tumor-selective expression of ROR1 has encouraged investigation of novel ROR1-targeted therapies including monoclonal antibodies, small molecule inhibitors, and chimeric antigen receptor T-cells, and preclinical trials have supported their safety and efficacy in inducing tumor growth suppression. Despite these advances in therapeutics, the role of ROR1 in oncogenic signaling is not yet fully understood. Through a comprehensive examination of ROR1 literature, this review will examine the biology of ROR1 as it relates to tumor progression, and demonstrate the viability of current ROR1-targeted therapies.
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