Genetic Aberrations Associated with Photodynamic Therapy in Colorectal Cancer Cells

Abstract

Photodynamic therapy (PDT) is a cancer treatment modality that utilizes three components: light (λ 650–750 nm), a photosensitizer (PS) and molecular oxygen, which upon activation renders the modality effective. Colorectal cancer has one of the highest incident rates as well as a high mortality rate worldwide. In this study, a zinc (Zn) metal-based phthalocyanine (ZnPcSmix) PS was used to determine its efficacy for the treatment of colon adenocarcinoma cells (DLD-1 and Caco-2). Photoactivation of the PS was achieved by laser irradiation at a wavelength of 680 nm. Dose responses were performed to establish optimal PS concentration and irradiation fluence. A working combination of 20 µM ZnPcSmix and 5 J/cm2 was used. Biochemical responses were determined after 1 or 24 h incubation post-treatment. Since ZnPcSmix is localized in lysosomes and mitochondria, mitochondrial destabilization analysis was performed monitoring mitochondrial membrane potential (MMP). Cytosolic acidification was determined measuring hydrogen peroxide (H2O2) levels in the cytoplasm. Having established apoptotic cell death induction, an apoptosis PCR array was performed to establish the apoptotic mechanism. In DLD-1 cells, expression of genes included 3 up-regulated and 20 down-regulated genes while in Caco-2 cells, there were 16 up-regulated and 22 down-regulated genes. In both cell lines, in up-regulated genes, there was a combination of pro- and anti-apoptotic genes that were significantly expressed. Gene expression results showed that more tumorigenic cells (DLD-1) went through apoptosis; however, they exhibit increased risk of resistance and recurrence, while less tumorigenic Caco-2 cells responded better to PDT, thus being suggestive of a better prognosis post-PDT treatment. In addition, the possible apoptotic mechanisms of cell death were deduced based on the genetic expression profiling of regulatory apoptotic inducing factors.

Combination of long-acting TRAIL and tumor cell-targeted photodynamic therapy as a novel strategy to overcome chemotherapeutic multidrug resistance and TRAIL resistance of colorectal cancer

“…TRAIL induces apoptosis by ligation to death receptors on the surface of cancer cells 31 , suggesting the possibility for enhancing the cytotoxicity of TRAIL by increasing membrane DR4 and/or DR5. It was reported that ROS could increase death receptor expression in cancer cells 17 , suggesting the synergy between PDT producing ROS 20 , 21 and TRAIL in killing CRC cells with both chemotherapeutic MDR and TRAIL resistance. In fact, we found that Ze-IR700-mediated PDT produced ROS and thus induced apoptosis of LS174T cells (Figure 3 D and E, Figure S5 ).…”

“…Photodynamic therapy (PDT) is efficient in producing ROS by triggering a photosensitizer in cells with laser light 18 , 19 . In fact, preliminary studies revealed that PDT induced death receptor expression in some cancer cells by producing ROS 20 , 21 , suggesting that PDT might synergize with TRAIL in killing CRC cells with chemotherapeutic MDR and TRAIL resistance. In addition, due to the unique mechanisms involved, including inducing apoptosis as well as damaging ABC transporters, PDT was considered a potential strategy to overcome MDR of cancers 22 , 23 .…”

Targeted Nanoparticle Photodynamic Diagnosis and Therapy of Colorectal Cancer

“…Moreover, within PDT applications, the MPc PSs wavelength of excitation ranges above 630 nm, allowing for better tissue light penetration, and improved PDT outcomes are often observed [6]. Studies by Abrahamse and Houreld (2019) reported that metalated zinc phthalocyanine sulfonated mix (ZnPcS mix ) PS localized within the intracellular lysosomal and mitochondria of in vitro treated CRC cell lines (DLD-1 and CaCo-2) and, thus, favored apoptotic cell death induction under 680 nm of laser irradiation [7]. However, it was previously reported that ZnPcS mix PSs have poor water solubility, which in turn encourages the formation of aggregates and hampers its PDT treatment outcomes [8].…”

A Novel Mechanism of the c-Myc/NEAT1 Axis Mediating Colorectal Cancer Cell Response to Photodynamic Therapy Treatment

“…As for CRC, Abrahamse et al. ( 25 ) found three upregulated and 20 downregulated genes within DLD-1 cells, while 16 upregulated and 22 downregulated genes within Caco-2 cells following a zinc (Zn) metal-based phthalocyanine (ZnPcSmix)-mediated PDT. Both pro-and anti-apoptotic genes were found among the upregulated genes.…”

“…Rupturing of lysosomes releases acidic lysosomal contents, such as cathepsins, consequently followed by activation of NAIP, which could precede inflammatory actions via NFkB-1 activation. The upregulation of NFkB1 and the downregulation of MCL1 , BCL2L2 , and BCL2L10 indicated unsuccessful evasion of apoptosis, DNA damage, and apoptosis ( 25 ). These previous findings suggest that the c-Myc/NEAT1 axis is one of the critical signaling pathways involved in CRC response to PDT treatment.…”