Photodynamic Therapy Mechanisms of Anti-tumor Activity PDF Download

Author: Edith Njeri Kabingu
Publisher:
ISBN:
Category :
Languages : en
Pages : 272

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Author: Valentina Rapozzi
Publisher: Springer
ISBN: 3319127306
Category : Medical
Languages : en
Pages : 253

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Book Description
This volume provides a comprehensive review of resistance induced by photodynamic therapy (PDT) in tumor cells. Understanding the underlying mechanisms in this process leads to the improvement of therapeutic modality, in combination with chemotherapy, immunotherapy, and radiotherapy. Photodynamic therapy is a minimally invasive therapeutic procedure that can exert a selective or preferential cytotoxic activity toward malignant cells. The procedure involves administration of an intrinsically non-toxic photosensitizing agent (PS) followed by irradiation at a wavelength corresponding to a visible absorption band of the sensitizer. In the presence of oxygen, a series of events lead to direct tumor cell death, damage to the microvasculature, and induction of a local inflammatory reaction. Studies reveal that PDT can be curative, particularly in early stage tumors and this volume explores the potential of PDT, but also reveals strategic approaches to overcome resistance in tumor cells.

Author: Michael R. Hamblin
Publisher: Artech House
ISBN: 1596932783
Category : Medical
Languages : en
Pages : 601

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Book Description
With today's focus on targeted and minimally invasive therapies, photodynamic therapy (PDT) is now being studied and used to combat many disease states and to investigate critical biological questions. This groundbreaking resource brings you the latest advances in photodynamic therapy and offers you a solid understanding of the design, delivery and dosimetry of the three basic ingredients of PDT - photosensitizers, light and oxygen. The book covers novel areas of mechanistic and innovative translational approaches. Moreover, it gives you an overview of the important medical applications of PDT, including approved treatments, clinical trials, and investigated therapies for cancer and non-malignant diseases.

Author: Edith Njeri Kabingu
Publisher:
ISBN: 9780542999611
Category :
Languages : en
Pages : 148

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Most cancer patients get standard therapies such as chemotherapy and radiation to treat their disease. These therapies are however mainly efficient in targeting the primary tumor and not metastatic disease. Immunotherapeutic strategies to target both primary and disseminated disease have been explored over the years. Photodynamic therapy (PDT) has been explored as a way to target the host's immune defenses to eradicate tumors. PDT is an established therapy for the treatment of various types of cancer. It uses a combination of light and photosensitizing drugs to induce damage to tumor tissue. Pre-clinical and clinical studies have shown that tumor control by PDT correlates with induction of anti-tumor immunity and suggest that the enhanced anti-tumor response may be effective against distant tumors. We have tested this hypothesis by measuring the ability of tumor bearing mice treated with PDT to control tumors outside the local treatment field. Two models were used to address this hypothesis. An experimental metastases model (EMT6) and a spontaneous metastases model (4T1). Using the experimental metastases model we have shown that in situ PDT of subcutaneous tumors of mice bearing both subcutaneous EMT6 mammary tumors and lung tumors results in a significant reduction in the number of lung tumors (an average of 6.5 +/- 3.9 tumors/lung) compared to mice whose subcutaneous tumors were surgically removed (an average of 41.2 +/- 8.5 tumors/lung). This control of tumors outside the field of treatment depended on treatment of tumors in the field because treatment of tumor free areas in tumor bearing mice did not result in control of tumors outside the treatment field. Furthermore, the ability to control these tumors depended upon CD8+ cells and appeared to be independent of CD4+ cells, as tumor control was maintained in mice depleted of CD4 expressing cells and SCID mice receiving CD8+ cells alone prior to PDT were able to control the growth of tumors outside the treatment field. In addition, the memory response did not appear to require CD4 + T cells since SCID mice inoculated with CD8+ were tumor free when challenged with EMT6 tumors 40 days after PDT treatment of primary EMT6 tumors. The mechanism by which this CD8+ T cell response may happen without CD4+ T cell help may be driven by NK cells because NK depleted SCID mice that were reconstituted with CD8 + T cells could not control distant EMT6 tumors following local PDT whereas those not depleted of NK cells but reconstituted with CD8+ T cells could. However the spontaneous metastases 4T1 model did not give us the same kind of results. The 4T1 model proved difficult to treat with PDT. There was no significant change in the number of spontaneous lung metastases after PDT of the primary tumor. A comparative study to investigate differences in PDT responses of 4T1 tumors compared to EMT6 tumors revealed that there may be immune suppression by regulatory T cells in 4T1 tumors. IL-6 production also appears to be enhanced after PDT of 4T1 tumors compared to EMT6 tumors (over 3 fold higher at the 8h time point). This could be driving proliferation and survival of 4T1 tumors. The expression of Bcl-2 in 4T1 and not EMT6 tumors and Bax in EMT6 and not 4T1 tumors supports the possibility that 4T1 tumors are protected from death and hence their inability to be killed by PDT. These studies suggest that in some tumors, PDT can be a potential immunotherapeutic strategy for controlling distant disease through induction of a specific host anti-tumor immune response mediated by CD8+ T cells. PDT may however not work for all tumors, but understanding differences in the response of various tumors may contribute to the development of strategies to overcome suppressive mechanisms.

Author: Flora Fitzgerald
Publisher: Nova Biomedical Books
ISBN: 9781536119121
Category : Photochemotherapy
Languages : en
Pages : 0

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Book Description
As a new concept of cancer treatment, photodynamic therapy (PDT) has gained great attention in the last few decades. Compared to classical treatments such as surgery, chemotherapy and radiotherapy, PDT is a noninvasive, localized treatment of lesions that shows fewer side effects and has low systemic toxicity. In Chapter One, the basic mechanisms, applications and functional nanomaterials-based drug delivery systems for photodynamic therapy of cancer are reviewed. Chapter Two summarizes the application of different carbon based nanomaterials as agents for PDT and discusses current state-of-the-art use of fullerenes and their derivatives, carbon nanotubes and graphene quantum dots in PDT. Chapter Three covers the benefits and pitfalls of using chemi- and bioluminescent systems as intracellular excitation sources in PDT. Bioluminescence is a widespread natural phenomenon, which consists on emission of light resulting from the oxidation of a substrate in a reaction catalyzed by an enzyme in a biological system. Chapter Four addresses in the synthesis, characterization, and photodynamic activity of a novel hydrophobic photosensitizer 5,10,15,20-tetrakis(benzo[b]thiophene) Porphyrin (BTP) and water soluble photosensitizer 5,10,15,20-Tetrakis(7- sulfonatobenzo[b]thiophene) Porphyrin (SBTP). The authors lab is engaged in the synthesis of PDT molecules incorporating benzothiophene moiety to the meso-position of porphyrin molecules. Chapter Five discusses the Guidelines for Gastroenterological Endoscopy in Patients on Oral Antithrombotic Treatment established by the Japan Gastroenterological Endoscopy Society (JGES).These guidelines classify endoscopic interventions according to the risk of hemorrhage and specify the management of various antithrombotic drugs. Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are classified as high-risk procedures for hemorrhage, but PDT is not included in the guidelines. Because PDT causes ischemic necrosis of tumor tissue, the authors say this could possibly be performed safely in patients on oral antithrombotic therapy. The authors of Chapter Six developed a method of the initial concentration of protoporphyrin-IX in the operated removing glioblastoma tissue using the calibration curve of the fluorescent intensity and the known Pp-IX concentration in order to estimate of the more correlated with the cure rate.

Author: Heidi Abrahamse
Publisher: Morgan & Claypool Publishers
ISBN: 1681743221
Category : Technology & Engineering
Languages : en
Pages : 109

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Janus, the ancient Roman god depicted with two faces is an appropriate metaphor for light therapy. In the right photodynamic therapy conditions, light is able to kill nearly anything that is living such as cancers, microorganisms, parasites, and more. On the opposite face, light of the correct wavelength and proper dose (photobiomodulation) can heal, regenerate, protect, revitalize and restore any kind of dead, damaged, stressed, dying, degenerating cells, tissue, or organ system. This book discusses both sides of Janus' face in regards to light therapy.

Author: Ravindra K Pandey
Publisher: World Scientific
ISBN: 9814719668
Category : Science
Languages : en
Pages : 563

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The main objective of this book is to present the recent applications of photodynamic therapy (PDT) in treating cancer and other diseases. The limitations associated with current PDT agents, and the synthetic designs that have been used in various laboratories are also discussed. The utility of certain tumor-avid agent for cancer imaging (fluorescence, PET, MRI) is also summarized. The book also includes the use of delivery vehicles, including nanoparticles in improving the tumor-specificity of the desired agents. The book is basically focused on the translational approach of drug development. By providing certain specific examples, a clear concept of moving a 'product' from the bench to bed-side is also discussed.To have a clear concept of drug development the book is divided in three parts — Medicinal Chemistry, Mechanistic and Clinical studies. Each part includes the contributions from the leading scientists with extensive experience in the respective field. The handbook is assembled by renowned scientists Dr Dougherty, known as the father of PDT, Dr Kessel, well known for his contributions on mechanism of PDT and Dr Pandey for his inventions in developing improved agents for PDT and cancer-imaging.

Author: Thomas John Dougherty
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 228

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Author: Lester Davids
Publisher: BoD – Books on Demand
ISBN: 9535109766
Category : Medical
Languages : en
Pages : 388

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The book Recent Advances in the Biology, Therapy and Management of Melanoma brings up-to-date information regarding a number of aspects which culminate in illuminating potential targets in the fight against melanoma. This book is intended to be a reference book for both the scientific and clinical communities and brings complicated subject matter together in an easy, readable way. Undoubtedly fundamental scientific understanding has to then be translated to the clinic in order for us to make significant strides in eradicating melanoma. It is hoped that scientists, clinicians, students and residents find this book useful in their studies on melanoma and that it not only expands their perspectives and views on the field, but challenges them to forge ahead towards discovering the ultimate cure.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 13

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One in 8 women in the United States will develop breast cancer during her lifetime. Deaths are due to tumors that have metastasized. Photodynamic therapy (PDT) is a promising cancer treatment in which a photosensitizer (PS) accumulates in tumors and is subsequently activated by visible light of an appropriate wavelength. PDT produces cell death and tumor ablation. Mechanisms include cytotoxicity to tumor cells, shutting down of the tumor vasculature, and the induction of a host immune response. Mechanisms involved in the PDT-mediated induction of anti-tumor immunity are not yet understood. Potential contributing factors are alterations in the tumor microenvironment via stimulation of proinflammatory cytokines and direct effects of PDT on the tumor that increase immunogenicity. We have studied PDT of 410.4 variant 4T1 tumors growing in the mammary fat pad (orthotopic) in Balb/c mice and which produce metastasis. We have shown that a PDT regimen that produces vascular shutdown and tumor necrosis leads to initial tumor ablation but the tumors recur at the periphery. We studied the combination of PDT with immunostimulating therapies. Low dose cyclophosphamide is a mechanism to deplete regulatory T cells; these cells play a role in the immunosuppression activity of tumors. In combination with PDT, cyclophosphamide increases the survival. The second alternative therapy is the use of a novel combination of the immunostimulant CpG Oligodeoxynucleotides (CpG-ODN) and PDT. CpG-ODN directly or indirectly triggers B cells, NK cells, macrophages and dendritic cells to proliferate, mature and secrete cytokines, chemokines and immunoglobulins. Both these novel combinations gave significantly enhanced therapeutic benefit not seen with single treatments alone. We propose that a rational choice of immune stimulant is an ideal addition to PDT regimens.