Abstract
M.Tech. (Biomedical Technology)
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...