A comparative study of the impact of low intensity laser irradiation on breast cancer cells and isolated breast cancer stem cells
- Authors: Kiro, Elodie Ndivito
- Date: 2019
- Subjects: Breast - Cancer , Cancer cells - Effect of radiation on , Lasers in medicine
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/292905 , uj:31838
- Description: Abstract: Healthy cells are programmed to follow an orderly path of growth, division and death. The slightest disturbance of these processes can lead to uncontrolled cell proliferation, which is the main characteristic of cancer. Cancer is a major health issue worldwide and one of the leading causes of death (Torre et al., 2015). Breast cancer is a dangerous disease responsible for most cancer-related deaths among women worldwide (Ferlay et al., 2014). This malignancy has become one of the major challenges faced by the affected women as well as the medical professionals in modern societies and has defied the major evolution of science. Despite the undeniable progress made in the field of cancer treatment, multiple side effects subsequent to the treatment are still major problems encounter and relapse after therapy is often observed. Post therapeutic cancer relapse is due to the failure of conventional therapeutic measures to eradicate malignant cells and it is believed to be caused by a minority cell population know as cancer stem cells (CSCs), which show resistance to these approaches (Mohr et al., 2015; Plaks et al., 2015). Therefore, the development of anti-tumour therapeutic approaches targeting CSCs can lead to more improved post-therapeutic outcomes in advanced stage cancer. Low intensity laser irradiation (LILI) refers to phototherapy using visible light in the wavelength range of 400 to 1000 nm (Abrahamse, 2011). The biomodulatory effect of LILI at the cellular level has made it an innovative treatment modality in a wide range of clinical conditions. Although LILI is capable of inducing both stimulatory and inhibitory responses at the cellular level due to its biphasic dose and wavelength related effects, more attention has been given to its biostimulatory effect and LILI has been used as a non-invasive treatment that has shown remarkable outcomes in reparative or cell replacement therapy, pain control and cancer therapy (Al-Watban et al., 2012; Pastar et al., 2014). In cancer therapy, the biostimulatory effect of LILI has mostly been used to ease the patient’s life by managing the side effects caused by either the conventional treatment... , M.Tech. (Biomedical Technology)
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- Authors: Kiro, Elodie Ndivito
- Date: 2019
- Subjects: Breast - Cancer , Cancer cells - Effect of radiation on , Lasers in medicine
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/292905 , uj:31838
- Description: Abstract: Healthy cells are programmed to follow an orderly path of growth, division and death. The slightest disturbance of these processes can lead to uncontrolled cell proliferation, which is the main characteristic of cancer. Cancer is a major health issue worldwide and one of the leading causes of death (Torre et al., 2015). Breast cancer is a dangerous disease responsible for most cancer-related deaths among women worldwide (Ferlay et al., 2014). This malignancy has become one of the major challenges faced by the affected women as well as the medical professionals in modern societies and has defied the major evolution of science. Despite the undeniable progress made in the field of cancer treatment, multiple side effects subsequent to the treatment are still major problems encounter and relapse after therapy is often observed. Post therapeutic cancer relapse is due to the failure of conventional therapeutic measures to eradicate malignant cells and it is believed to be caused by a minority cell population know as cancer stem cells (CSCs), which show resistance to these approaches (Mohr et al., 2015; Plaks et al., 2015). Therefore, the development of anti-tumour therapeutic approaches targeting CSCs can lead to more improved post-therapeutic outcomes in advanced stage cancer. Low intensity laser irradiation (LILI) refers to phototherapy using visible light in the wavelength range of 400 to 1000 nm (Abrahamse, 2011). The biomodulatory effect of LILI at the cellular level has made it an innovative treatment modality in a wide range of clinical conditions. Although LILI is capable of inducing both stimulatory and inhibitory responses at the cellular level due to its biphasic dose and wavelength related effects, more attention has been given to its biostimulatory effect and LILI has been used as a non-invasive treatment that has shown remarkable outcomes in reparative or cell replacement therapy, pain control and cancer therapy (Al-Watban et al., 2012; Pastar et al., 2014). In cancer therapy, the biostimulatory effect of LILI has mostly been used to ease the patient’s life by managing the side effects caused by either the conventional treatment... , M.Tech. (Biomedical Technology)
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Evaluation of photodynamic treatment in lung cancer cells induced by targeted drug delivery
- Authors: Mokwena, Mpho Gift
- Date: 2019
- Subjects: Lungs - Cancer - Photochemotherapy , Lungs - Cancer - Treatment
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/296760 , uj:32337
- Description: Abstract: Lung cancer has been established as one of the world’s leading causes of cancer related deaths (Siegel et al., 2018). Moreover, it is expected that the lung cancer mortality rate will increase by up to 3 million cases by 2035 (Sadanala et al., 2012). Thus current research has been focused on enhancing unconventional treatment modalities such as photodynamic therapy (PDT), due to the adverse side effects commonly linked with conventional lung cancer treatments (chemotherapy, radiation therapy and surgery) (Mokwena et al., 2018). Unconventional treatments such as PDT, carry the potential to be specifically targeted and are actively absorbed by tumour cells alone, leaving normal surrounding tissues unharmed, with limited side effects post-treatment (Master and Sen Gupta, 2012). PDT is a clinically approved cancer therapy, which is based on 3 fundamental factors, namely light, oxygen and photosensitizer (PS) drug (van Straten et al., 2018). These factors come together to bring about tumour destruction by exposing the PS drug administered to light of specific wavelength, thus stimulating the production of ROS (van Straten et al., 2018). However, the efficacy of ROS production for tumour damage is highly dependent on the uptake of the PS in tumour cells (El Hussein et al., 2015). Thus PS selective or targeted uptake and delivery in tumour cells is a crucial factor in PDT cancer drug absorption studies. Generally, within non-targeted drug delivery mechanisms, only small amounts of PS is able to passively accumulate in tumour sites due to the enhanced permeability and retention (EPR) effect and the remainder distributes into healthy tissues, causing unwanted side effects (Kawczyk-Krupka et al., 2016). This study sought to improve the efficacy of PDT by developing a actively specific receptor based photosynthetic nanocarrier drug which would promote the active uptake and absorption of PS drugs in tumour sites only, avoiding these unwanted side effects... , M.Tech. (Biomedical Technology)
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- Authors: Mokwena, Mpho Gift
- Date: 2019
- Subjects: Lungs - Cancer - Photochemotherapy , Lungs - Cancer - Treatment
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/296760 , uj:32337
- Description: Abstract: Lung cancer has been established as one of the world’s leading causes of cancer related deaths (Siegel et al., 2018). Moreover, it is expected that the lung cancer mortality rate will increase by up to 3 million cases by 2035 (Sadanala et al., 2012). Thus current research has been focused on enhancing unconventional treatment modalities such as photodynamic therapy (PDT), due to the adverse side effects commonly linked with conventional lung cancer treatments (chemotherapy, radiation therapy and surgery) (Mokwena et al., 2018). Unconventional treatments such as PDT, carry the potential to be specifically targeted and are actively absorbed by tumour cells alone, leaving normal surrounding tissues unharmed, with limited side effects post-treatment (Master and Sen Gupta, 2012). PDT is a clinically approved cancer therapy, which is based on 3 fundamental factors, namely light, oxygen and photosensitizer (PS) drug (van Straten et al., 2018). These factors come together to bring about tumour destruction by exposing the PS drug administered to light of specific wavelength, thus stimulating the production of ROS (van Straten et al., 2018). However, the efficacy of ROS production for tumour damage is highly dependent on the uptake of the PS in tumour cells (El Hussein et al., 2015). Thus PS selective or targeted uptake and delivery in tumour cells is a crucial factor in PDT cancer drug absorption studies. Generally, within non-targeted drug delivery mechanisms, only small amounts of PS is able to passively accumulate in tumour sites due to the enhanced permeability and retention (EPR) effect and the remainder distributes into healthy tissues, causing unwanted side effects (Kawczyk-Krupka et al., 2016). This study sought to improve the efficacy of PDT by developing a actively specific receptor based photosynthetic nanocarrier drug which would promote the active uptake and absorption of PS drugs in tumour sites only, avoiding these unwanted side effects... , M.Tech. (Biomedical Technology)
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Influence of 660 nm on the differentiation of fibroblasts into myofibroblasts
- Authors: Mokoena, Dimakatso Ribone
- Date: 2018
- Subjects: Fibroblasts , Myofibroblasts , Lasers - Therapeutic use
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/296912 , uj:32356
- Description: Abstract: Please refer to full text to view abstract. , M.Tech. (Biomedical Technology)
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- Authors: Mokoena, Dimakatso Ribone
- Date: 2018
- Subjects: Fibroblasts , Myofibroblasts , Lasers - Therapeutic use
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/296912 , uj:32356
- Description: Abstract: Please refer to full text to view abstract. , M.Tech. (Biomedical Technology)
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Photodynamic therapy using sulfonated aluminium phthalocyaninemix for the eradication of cervical cancer and cervical cancer stem cells
- Authors: Chizenga, Elvin Peter
- Date: 2018
- Subjects: Cervix uteri - Cancer - Treatment , Photochemotherapy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/296751 , uj:32336
- Description: Abstract: Treatment of many cancers including carcinoma of the cervix has been problematic although, scientists across the globe are trying to find new ways of combating the hurdles in cancer treatment. Cervical cancer is a very common gynecologic malignancy worldwide and especially in developing countries, it is the leading cause of cancer related deaths among women, with approximately half of a million cases diagnosed each year (WHO, 2014, Ferlay et al., 2010). It is, a malignant neoplasm that is initiated by transformation of the basal layer cells of the cervix upon infection with the Human Papillomavirus, HPV and progressively spreads through the entire thickness of the cervix uteri. Current treatments including surgery, chemotherapy and radiation, administered separately or combined have shown limited therapeutic potential with severe associated side effects, poor prognosis, high rates of cancer recurrence and reduced quality of life (Lee et al., 2016). With intensive focus on the study of tumor biology and immunology in recent years, numerous studies have reported the presence of a subpopulation of cells in cancer that is distinct from the cells of the entire tumor. These cells possess stem cell properties and have been associated with tumor generation, metastasis and resistance to therapy. Referred to as cancer initiating cells or more commonly, cancer stem cells (CSCs), these cells have been isolated from many tumors including cervical cancer and their role in tumor biology and treatment resistance has been well characterized. The high incidence of tumor relapse after conventional chemotherapy in cervical cancer has implicated CSCs as the main cause. CSCs have also shown a high treatment resistance to both chemo and radiation therapy (Holohan et al., 2013). CSCs have the highest potential to escape damage by cytotoxic and genotoxic drugs because of their inherent properties of enhanced DNA repair mechanisms, characteristics of their stem cell niche, and the ability to efflux (pump out) drugs out of the cell. Due to these... , M.Tech. (Biomedical Technology)
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- Authors: Chizenga, Elvin Peter
- Date: 2018
- Subjects: Cervix uteri - Cancer - Treatment , Photochemotherapy
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/296751 , uj:32336
- Description: Abstract: Treatment of many cancers including carcinoma of the cervix has been problematic although, scientists across the globe are trying to find new ways of combating the hurdles in cancer treatment. Cervical cancer is a very common gynecologic malignancy worldwide and especially in developing countries, it is the leading cause of cancer related deaths among women, with approximately half of a million cases diagnosed each year (WHO, 2014, Ferlay et al., 2010). It is, a malignant neoplasm that is initiated by transformation of the basal layer cells of the cervix upon infection with the Human Papillomavirus, HPV and progressively spreads through the entire thickness of the cervix uteri. Current treatments including surgery, chemotherapy and radiation, administered separately or combined have shown limited therapeutic potential with severe associated side effects, poor prognosis, high rates of cancer recurrence and reduced quality of life (Lee et al., 2016). With intensive focus on the study of tumor biology and immunology in recent years, numerous studies have reported the presence of a subpopulation of cells in cancer that is distinct from the cells of the entire tumor. These cells possess stem cell properties and have been associated with tumor generation, metastasis and resistance to therapy. Referred to as cancer initiating cells or more commonly, cancer stem cells (CSCs), these cells have been isolated from many tumors including cervical cancer and their role in tumor biology and treatment resistance has been well characterized. The high incidence of tumor relapse after conventional chemotherapy in cervical cancer has implicated CSCs as the main cause. CSCs have also shown a high treatment resistance to both chemo and radiation therapy (Holohan et al., 2013). CSCs have the highest potential to escape damage by cytotoxic and genotoxic drugs because of their inherent properties of enhanced DNA repair mechanisms, characteristics of their stem cell niche, and the ability to efflux (pump out) drugs out of the cell. Due to these... , M.Tech. (Biomedical Technology)
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An investigation into the synergistic effect of doxorubicin and photodynamic therapy on MCF-7 breast cancer cells
- Authors: Chekwube, Aniogo Eric
- Date: 2017
- Subjects: Breast - Cancer - Treatment , Cancer - Treatment
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/273415 , uj:29127
- Description: Abstract: Cancer is a genetic disease characterised by uncontrolled cellular proliferation and metastasis that have caused significant mortality in developing countries of Africa. Despite research and awareness, breast cancer remains a major health threat amongst women with more than one million new cases diagnosed globally every year. Chemotherapy is the standard treatment modality for most cancers, which increases a patient’s life expectancy yet poses a major challenge of drug resistance, killing of non-cancer cells and severe side effects. Doxorubicin (DOX) is a broad-spectrum antibiotic and anticancer drug used to treat a variety of human malignancies like breast cancer, cervical cancer and leukaemia. Its molecular mechanism of action includes; intercalating with DNA and disruption of topoisomerase II enzyme, thus halting DNA replication and ultimately leading to cell death. Conversely, its use has been limited despite its effect against proliferating cancer cells due to the risk of cardiac damage and acquisition of resistance associated with it. Photodynamic therapy (PDT) is a photochemical process of inducing localized tissue damage through administration of a photosensitizer (PS) followed by light irradiation that initiates tumour damage. PDT treatment combines the interaction between an excited PS and molecular oxygen to cause injury and death of targeted cells. PDT is considered a safe and promising therapy due to the possibility of the use of reactive oxygen species (ROS) towards killing cancer cells. A combination of therapy to treat cancer malignancies are at the forefront of research with the aim to reduce drug doses and diminish the possibility of resistance. Combining chemotherapy and PDT could be a promising and effective approach in inducing cancer cell death given multitarget strategy. In an attempt to achieve additive and preferably synergistic effects on cancer therapy, the present study aimed at determining the concentration of DOX and sulphonated Zinc Phthalocyanine (ZnPcS)-mediated PDT causing a 50% decrease in viability of Michigan Cancer Foundation-7 (MCF-7) breast cancer cells (IC50) in order to determine cellular response and identify the mechanism of cell death induced by the combination of DOX and ZnPcS-mediated PDT on MCF-7 breast cancer cells... , M.Tech. (Biomedical Technology)
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- Authors: Chekwube, Aniogo Eric
- Date: 2017
- Subjects: Breast - Cancer - Treatment , Cancer - Treatment
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/273415 , uj:29127
- Description: Abstract: Cancer is a genetic disease characterised by uncontrolled cellular proliferation and metastasis that have caused significant mortality in developing countries of Africa. Despite research and awareness, breast cancer remains a major health threat amongst women with more than one million new cases diagnosed globally every year. Chemotherapy is the standard treatment modality for most cancers, which increases a patient’s life expectancy yet poses a major challenge of drug resistance, killing of non-cancer cells and severe side effects. Doxorubicin (DOX) is a broad-spectrum antibiotic and anticancer drug used to treat a variety of human malignancies like breast cancer, cervical cancer and leukaemia. Its molecular mechanism of action includes; intercalating with DNA and disruption of topoisomerase II enzyme, thus halting DNA replication and ultimately leading to cell death. Conversely, its use has been limited despite its effect against proliferating cancer cells due to the risk of cardiac damage and acquisition of resistance associated with it. Photodynamic therapy (PDT) is a photochemical process of inducing localized tissue damage through administration of a photosensitizer (PS) followed by light irradiation that initiates tumour damage. PDT treatment combines the interaction between an excited PS and molecular oxygen to cause injury and death of targeted cells. PDT is considered a safe and promising therapy due to the possibility of the use of reactive oxygen species (ROS) towards killing cancer cells. A combination of therapy to treat cancer malignancies are at the forefront of research with the aim to reduce drug doses and diminish the possibility of resistance. Combining chemotherapy and PDT could be a promising and effective approach in inducing cancer cell death given multitarget strategy. In an attempt to achieve additive and preferably synergistic effects on cancer therapy, the present study aimed at determining the concentration of DOX and sulphonated Zinc Phthalocyanine (ZnPcS)-mediated PDT causing a 50% decrease in viability of Michigan Cancer Foundation-7 (MCF-7) breast cancer cells (IC50) in order to determine cellular response and identify the mechanism of cell death induced by the combination of DOX and ZnPcS-mediated PDT on MCF-7 breast cancer cells... , M.Tech. (Biomedical Technology)
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Synthesis of zinc phthalocyanine-gold nanoparticles conjugated compounds and determination of photodynamic effects in a breast cancer cell line
- Authors: Mfouo-Tynga, Ivan Sosthene
- Date: 2017
- Subjects: Breast - Cancer - Photochemotherapy , Nanomedicine
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/226525 , uj:22905
- Description: D.Tech. (Biomedical Technology) , Abstract: Cancer is a disease that occurs following mutations in the genes, which control cell growth. These mutations are caused by different causes and viral infections are among those. Cancer cells can conquer other cells and tissues causing changes to their deoxyribonucleic acids (DNA). Cancer appears almost incurable once it has started to metastasize and invade other body organs. At that stage, any therapeutic intervention was believed to cause more harm than curative effects (Gallucci, 1985; Kardinal and Yarbro, 1979). Late diagnosis and treatment reduces the possibility of an effective cure (He et al., 2007). The development of a malignant tumour from cells in the breast is known as breast cancer. Breast cancer is generally initiated in the stromal cells, which are fibrous and fatty tissues, or in the glandular cells; which produce breast milk (American Cancer Society, 2014). Breast cancer is the leading cancer among women and cause of cancer death worldwide (Ferlay et al., 2008). It is a heterogeneous disease with several markers, which are essential for diagnosis and include the estrogen receptors (ER), progesterone receptors (PR) and human epidermal growth factor receptor 2 (HER-2) (Mosoyan et al., 2013; Yang et al., 2013). Like all cancer, breast cancer can be cured if diagnosed at an early stage. Treatment of cancer has evolved from palliative therapies to conventional therapies, which consist of surgery, hormonal therapy, radiation therapy, immunotherapy, chemotherapy, and adjuvant therapy. (Gallucci, 1985; Kardinal and Yarbro, 1979). Photodynamic therapy (PDT) has become popular as an alternative cancer treatment modality. PDT depends on molecular oxygen and photodynamic action for effective cancer destruction (Von Tappeiner and Jesionek, 1903; Von Tappeiner and Joblauer, 1904). Today, PDT is designated as a chronological and minimally invasive cancer therapy with numerous benefits over conventional treatments. The initial step of this therapy consists of the administration of drugs to patients,..
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- Authors: Mfouo-Tynga, Ivan Sosthene
- Date: 2017
- Subjects: Breast - Cancer - Photochemotherapy , Nanomedicine
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/226525 , uj:22905
- Description: D.Tech. (Biomedical Technology) , Abstract: Cancer is a disease that occurs following mutations in the genes, which control cell growth. These mutations are caused by different causes and viral infections are among those. Cancer cells can conquer other cells and tissues causing changes to their deoxyribonucleic acids (DNA). Cancer appears almost incurable once it has started to metastasize and invade other body organs. At that stage, any therapeutic intervention was believed to cause more harm than curative effects (Gallucci, 1985; Kardinal and Yarbro, 1979). Late diagnosis and treatment reduces the possibility of an effective cure (He et al., 2007). The development of a malignant tumour from cells in the breast is known as breast cancer. Breast cancer is generally initiated in the stromal cells, which are fibrous and fatty tissues, or in the glandular cells; which produce breast milk (American Cancer Society, 2014). Breast cancer is the leading cancer among women and cause of cancer death worldwide (Ferlay et al., 2008). It is a heterogeneous disease with several markers, which are essential for diagnosis and include the estrogen receptors (ER), progesterone receptors (PR) and human epidermal growth factor receptor 2 (HER-2) (Mosoyan et al., 2013; Yang et al., 2013). Like all cancer, breast cancer can be cured if diagnosed at an early stage. Treatment of cancer has evolved from palliative therapies to conventional therapies, which consist of surgery, hormonal therapy, radiation therapy, immunotherapy, chemotherapy, and adjuvant therapy. (Gallucci, 1985; Kardinal and Yarbro, 1979). Photodynamic therapy (PDT) has become popular as an alternative cancer treatment modality. PDT depends on molecular oxygen and photodynamic action for effective cancer destruction (Von Tappeiner and Jesionek, 1903; Von Tappeiner and Joblauer, 1904). Today, PDT is designated as a chronological and minimally invasive cancer therapy with numerous benefits over conventional treatments. The initial step of this therapy consists of the administration of drugs to patients,..
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Photobiomodulatory effects of low intensity laser irradiation on isolated lung cancer stem cells
- Authors: Crous, Anna Magdalena
- Date: 2016
- Subjects: Lungs - Cancer - Treatment , Cancer cells - Effect of radiation on , Lasers in medicine
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/226444 , uj:22895
- Description: M.Tech. (Biomedical Technology) , Abstract: Lung cancer remains a primary threat contributing to high cancer mortality rates and relapse. An attributing factor, metastasis, has been concluded to be due to stem-like cells possessing cancer properties. Cancer stem cells (CSCs) portray characteristics similar to embryonic and adult stem cells in which they are capable of indefinite proliferation, self-renewal and specialize in cell differentiation. Low Intensity Laser Irradiation (LILI) is a light therapy used for treating various disease states and cancer conditions. In addition to having stimulatory effects on irradiated cells and tissues by upregulating metabolism via proliferation, formation of capillaries and activate adenosine triphosphate (ATP) synthase production, LILI has also been shown to stimulate, as well as to inhibit cellular processes at different intensities. LILI used in combination with a photosensitive chemical that targets specific cancer cells, known as photodynamic therapy (PDT), a process whereby a photosensitive chemical is activated with laser light at a specific wavelength producing reactive oxygen species (ROS) that results in cancer cell death. Since previous studies (Abrahamse, 2010) have shown that laser irradiation has different effects on various cells and tissues, the aim of this exploratory study was to investigate the possible outcomes that various laser intensities and wavelengths would have on isolated lung CSCs. Lung cancer cells (A549) containing a subpopulation of CSCs, positive for the antigenic marker CD 133, were irradiated with a low fluence LILI (LF-LILI) of 5 – 20 J/cm2 and a high fluence LILI (HF-LILI) of 40 J/cm2. The lasers used emitted wavelengths of 636, 825 and 1060 nm. After treatment with low and high fluence LILI, biochemical assays were conducted on the treated lung CSCs and their control groups over a time period of 24, 48 and 72 h to determine various cellular responses. Cellular viability, proliferation, death and cytotoxicity assays allowed for various LILI treatment outcomes to be evaluated. Results showed a successful isolation of lung CSCs, since they were positive for the CD 133 cell surface marker. Post irradiation imaging analysis revealed no morphological changes in control cells receiving no irradiation and only normal increases in cell density over time due to maintenance of viability and proliferation was observed. Within the test samples that received LF-LILI treatment, similar responses when compared to control cells was observed. However, HF-LILI of...
- Full Text:
- Authors: Crous, Anna Magdalena
- Date: 2016
- Subjects: Lungs - Cancer - Treatment , Cancer cells - Effect of radiation on , Lasers in medicine
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/226444 , uj:22895
- Description: M.Tech. (Biomedical Technology) , Abstract: Lung cancer remains a primary threat contributing to high cancer mortality rates and relapse. An attributing factor, metastasis, has been concluded to be due to stem-like cells possessing cancer properties. Cancer stem cells (CSCs) portray characteristics similar to embryonic and adult stem cells in which they are capable of indefinite proliferation, self-renewal and specialize in cell differentiation. Low Intensity Laser Irradiation (LILI) is a light therapy used for treating various disease states and cancer conditions. In addition to having stimulatory effects on irradiated cells and tissues by upregulating metabolism via proliferation, formation of capillaries and activate adenosine triphosphate (ATP) synthase production, LILI has also been shown to stimulate, as well as to inhibit cellular processes at different intensities. LILI used in combination with a photosensitive chemical that targets specific cancer cells, known as photodynamic therapy (PDT), a process whereby a photosensitive chemical is activated with laser light at a specific wavelength producing reactive oxygen species (ROS) that results in cancer cell death. Since previous studies (Abrahamse, 2010) have shown that laser irradiation has different effects on various cells and tissues, the aim of this exploratory study was to investigate the possible outcomes that various laser intensities and wavelengths would have on isolated lung CSCs. Lung cancer cells (A549) containing a subpopulation of CSCs, positive for the antigenic marker CD 133, were irradiated with a low fluence LILI (LF-LILI) of 5 – 20 J/cm2 and a high fluence LILI (HF-LILI) of 40 J/cm2. The lasers used emitted wavelengths of 636, 825 and 1060 nm. After treatment with low and high fluence LILI, biochemical assays were conducted on the treated lung CSCs and their control groups over a time period of 24, 48 and 72 h to determine various cellular responses. Cellular viability, proliferation, death and cytotoxicity assays allowed for various LILI treatment outcomes to be evaluated. Results showed a successful isolation of lung CSCs, since they were positive for the CD 133 cell surface marker. Post irradiation imaging analysis revealed no morphological changes in control cells receiving no irradiation and only normal increases in cell density over time due to maintenance of viability and proliferation was observed. Within the test samples that received LF-LILI treatment, similar responses when compared to control cells was observed. However, HF-LILI of...
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