phytochlorin and Colonic-Neoplasms

Photodynamic therapy (PDT) -a minimally invasive anti-cancer therapy-is undergoing experimental studies to increase its anti-cancer effects. This study investigated the influence of iron on the anti-cancer effects of PDT.. PDT was performed in a cancer-bearing mouse model, which was created by using a murine colon carcinoma (CT26) cell line after administration of Photolon and iron. Tumor volume and the results of TdT-mediated dUTP-biotin nick end labeling (TUNEL), 8-OHdG, and TBARS assays were used to measure anti-cancer effect.. On day 14, tumor volume had increased by 49% in the PDT group and decreased by 72% in the iron+PDT group. The percentage of TUNEL-positive cells in tumor tissues was 45% in the PDT group and 69% in the iron+PDT group, suggesting that the proportion of TUNEL-positive cells had increased in the iron+PDT group. The 8-OHdG content in tumor tissues was 33% higher in the iron+PDT group than in the PDT group. The TBARS content in tumor tissues was 46% higher in the iron+PDT group than in the PDT group.. Iron enhances the anti-cancer effect of PDT using Photolon, most likely by increasing oxidative damage.

Topics: Animals; Apoptosis; Cell Line, Tumor; Colonic Neoplasms; Disease Models, Animal; Iron; Mice; Photochemotherapy; Photosensitizing Agents; Porphyrins; Thiobarbituric Acid Reactive Substances

Colorectal cancer is one of the most common gastrointestinal malignancies. Photodynamic therapy (PDT) is a novel and non-invasive treatment for tumors as PDT features small trauma, good applicability, andaccurate targeting. PDT may also be a potential treatment for colon cancer as itmay may induce suppressive effects on metastatic potential.. However, the molecular mechanism of the Chlorin e6 Photodynamic therapy (Ce6-PDT) inhibiting the migration of human colon cancer SW620 cells remains unclear.. Scratch wound healing assay, scanning electron microscope, MTT, immunofluorescence and laser confocal technique were used to investigate the suppressive effects of Ce6-PDT on the SW620 cells migration, pseudopodia, viability and the actin cytoskeleton. The effect of Ce6-PDT on actin-Filaments and signaling molecules of the Rac1/PAK1/LIMK1/cofilin signaling pathway in SW620 cells were examined by western blot analysis. RNA interference (RNAi) technology was used to establish siRNA-Rac1/SW620 cells. The combined effects of Ce6-PDT and RNAi on colon cancer SW620 cells was investigated by the same technology and methods mentioned above to clarify the signal transduction effect of Rac1/PAK1/LIMK1/cofilin signaling pathway in Ce6-PDT caused inhibition of SW620 cell migration.. The healing and migration rate of the SW620 cells was significantly reduced and the cell pseudopodia were reduced or disappeared by Ce6-PDT. The Immunofluorescence and western blot analysis results showed that Ce6-PDT destroy microfilament's original structure and significantly downregulated F-actin protein expression. The Rac1/PAK1/LIMK1/cofilin signaling pathway was downregulated by Ce6-PDT. Furthermore, the RNAi significantly strengthened the effect of Ce6-PDT on colon cancer SW620 cells migration.. Actin cytoskeleton and protrusions of SW620 cells correlate with its migration ability. Ce6-PDT suppresses SW620 cells migration by downregulating the Rac1/PAK1/LIMK1/cofilin signaling pathway, and its suppressive effect was enhanced by knocking down Rac1 gene expression.

Topics: Actin Depolymerizing Factors; Cell Line, Tumor; Chlorophyllides; Colonic Neoplasms; Down-Regulation; Humans; Lim Kinases; p21-Activated Kinases; Photochemotherapy; Photosensitizing Agents; Porphyrins; rac1 GTP-Binding Protein; Signal Transduction

Photodynamic therapy (PDT) is based on photochemical and photobiological reactions mediated by photosensitizers to achieve a killing effect on diseased cells. It is used in the treatment of malignant tumors, precancerous lesions and infections.. In order to provide theoretical data for further study of the mechanism of PDT for colorectal cancer, SW480 cells were treated with Ce6-PDT and effect of photodynamic therapy (Ce6-PDT) on cytoskeleton and E-cadherin protein were observed.. The survival of SW480 cells was detected by MTT assay. The morphological changes of SW480 cells after Ce6-PDT were observed by scanning electron microscope (ESM). The migration ability was determined by wound healing assay. The distribution of F-actin in the cytoplasm was observed with confocal laser scanning microscope. Western blot analysis was used to detect the expression of cytoskeleton proteins in SW480 cells after Ce6-PDT.. Compared with the control group, there was significant difference in cell viability of cells treated with Ce6-PDT (F = 78753.78, P < 0.05). The pseudopodia almost disappeared and cellular atrophy was clearly visible in the cells of Ce6-PDT group. The migration ability of cells treated with Ce6-PDT for 48 h was significantly lower than the control group (F = 11.794, P<0.001). The result of Western blot analysis showed that the expression of F-actin, α-tubulin, β-tubulin and Vimentin in the cells treated with Ce6-PDT were significantly higher than that in the control group (F = 22.251,8.109, 5.840, 4.685 and 18.754, P < 0.05). The expression of E-cadherin in cells of Ce6-PDT group was significantly higher than that in control group (F = 30.882, P < 0.001). Perhaps Ce6-PDT inhibits the proliferation and migration of colon cancer SW480 cells by enhancing the expression of E-cadherin, causing the disappearance of cell pseudopodia and the destruction of cytoskeleton.. The destruction of cytoskeleton might be one of the reasons for the inhibition of cell proliferation and migration by Ce6-PDT.

Topics: Apoptosis; Cell Line, Tumor; Chlorophyllides; Colonic Neoplasms; Cytoskeleton; Humans; Photochemotherapy; Photosensitizing Agents; Porphyrins

Up to now, limited tumor penetration and poor therapeutic efficiency of drug-loaded nanoparticles are still the major challenges in nanomedicines for cancer chemotherapy. In photodynamic therapy, photosensitizers are often used to generate cytotoxic reactive oxygen species to kill cancer cells. Here, we report a kind of ROS-responsive nanoparticles with light-triggered size-reducing for enhanced tumor penetration and in vivo drug delivery to improve therapeutic efficiency. The nanoparticles were constructed by the self-assembly of an amphiphilic hyperbranched polyphosphoester containing thioketal units and photosensitizers, which is synthesized through the self-condensing ring-opening polymerization of a novel cyclic phosphate monomer and then end-capped with photosensitizer Chlorin e6. These nanoparticles have an initial averaged diameter of ∼210 nm, which can be used as drug carriers to load camptothecin with relatively stable in blood circulation. The CPT-loaded nanoparticles can be concentrated in tumor tissues through the long blood circulation and enhanced permeability and retention effect. Upon 660 nm laser irradiation on tumor tissues, the Ce6s in nanoparticles can effectively generate ROS to kill cancer cells meanwhile cleave the thioketal units to sequentially reduce the size of nanoparticles, which facilitate them more efficient tumor penetration with a programmable release of CPT. Both in vitro and in vivo studies confirmed the above results. Such ROS-responsive nanoparticles with light-triggered size-reducing provided a feasible approach to improve drug tumor penetration and achieve satisfied therapeutic efficacy.

Topics: Animals; Antineoplastic Agents, Phytogenic; Camptothecin; Chlorophyllides; Colonic Neoplasms; Delayed-Action Preparations; Drug Delivery Systems; HT29 Cells; Humans; Light; Mice, Nude; Nanoparticles; Photosensitizing Agents; Porphyrins; Reactive Oxygen Species

The aim of the present study is to fabricate hydrogel as a photosensitizer (PS) for photodynamic therapy. Chlorin e6 (Ce6)-fucoidan/alginates@gellam gum (Ce6-Fu/AL@GG)-based hydrogel was fabricated and characterised in terms of morphology and functional groups. MTT assay was used to check toxicity and also performed scratch assay for wound healing property of Ce6-Fu/AL@GGH. Fourier transform infrared spectroscopy (FT-IR) confirmed the existence of physical interactions between polysaccharides. Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) analysis confirmed a decrease in the thermal stability of the fabricated hydrogel. Scanning electron microscope (SEM) and Transmission electron microscope (TEM) images demonstrated porous matrixes representing homogeneous dispersion of nanoparticles in the hydrogel. Cytotoxicity tests revealed that a decrease in the cell viability occurred in PDT after 48 h treatment. Both Ce6 and laser irradiation induced the HT-29 apoptotic effect that was mediated by intracellular ROS generation and mitochondrial damage. The laser-treated hydrogel was effective in inhibiting HT-29 cell growth. Ce6-Fu/AL@GG hydrogel can be a promising platform for PDT on cancer treatment.

Topics: Apoptosis; Cell Proliferation; Cell Survival; Chlorophyllides; Colonic Neoplasms; Drug Screening Assays, Antitumor; HT29 Cells; Humans; Hydrogels; Particle Size; Photochemotherapy; Photosensitizing Agents; Porphyrins; Reactive Oxygen Species; Surface Properties; Tumor Cells, Cultured; Wound Healing

Nanophotosensitizer composed of methoxy poly(ethylene glycol) (MePEG) and chlorin e6 (Ce6) (abbreviated as Pe6) was synthesized for efficient delivery of Ce6 to the colon cancer cells. Pe6 nanophotosensitizer has small diameter less than 100 nm with spherical shape and core-shell structure. They were activated in aqueous solution while Ce6 was quenched due to its poor aqueous solubility. They showed no intrinsic cytotoxicity against normal cells and colon cancer cells. Pe6 nanophotosensitizers showed enhanced cellular uptake, phototoxicity, and reactive oxygen species (ROS) generation at in vitro cell culture experiment. Furthermore, they showed improved tumor tissue penetration and accumulation in vivo animal studies. We suggested Pe6 nanophotosensitizers as an ideal candidate for PDT of colon cancer.

Topics: Animals; Cell Line, Tumor; Chlorophyllides; Colonic Neoplasms; Nanocomposites; Photochemotherapy; Photosensitizing Agents; Polyethylene Glycols; Porphyrins

Photodynamic therapy (PDT) is a novel and non-invasive treatment that induces apoptosis and autophagy. Autophagy could play a pro-survival role, thus inhibiting autophagic activity might be a promising method to enhance the effectiveness of PDT for tumors. In the present study, photosensitizer Chlorin e6 (Ce6) was found to mainly locate in endoplasmic reticulum, and to a lesser extent in mitochondria and lysosome. Chlorin e6 photodynamic therapy (Ce6-PDT) could kill human colon cancer SW620 cells by inducing apoptotic cell death, and autophagy also induced by Ce6-PDT in colon cancer cells. More importantly, autophagy played a pro-survival role. Its inhibition enhanced Ce6-PDT-associated apoptotic cell death because cells pretreated with the typical autophagy inhibitor 3-methyladenine exhibited higher cytotoxicity and apoptotic cell death.

Topics: Apoptosis; Autophagy; Cell Survival; Chlorophyllides; Colonic Neoplasms; Dose-Response Relationship, Drug; Flow Cytometry; Humans; Microscopy, Confocal; Neoplasm Metastasis; Photochemotherapy; Photosensitizing Agents; Porphyrins

While immunotherapy has become a highly promising paradigm for cancer treatment in recent years, it has long been recognized that photodynamic therapy (PDT) has the ability to trigger antitumor immune responses. However, conventional PDT triggered by visible light has limited penetration depth, and its generated immune responses may not be robust enough to eliminate tumors. Herein, upconversion nanoparticles (UCNPs) are simultaneously loaded with chlorin e6 (Ce6), a photosensitizer, and imiquimod (R837), a Toll-like-receptor-7 agonist. The obtained multitasking UCNP-Ce6-R837 nanoparticles under near-infrared (NIR) irradiation with enhanced tissue penetration depth would enable effective photodynamic destruction of tumors to generate a pool of tumor-associated antigens, which in the presence of those R837-containing nanoparticles as the adjuvant are able to promote strong antitumor immune responses. More significantly, PDT with UCNP-Ce6-R837 in combination with the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) checkpoint blockade not only shows excellent efficacy in eliminating tumors exposed to the NIR laser but also results in strong antitumor immunities to inhibit the growth of distant tumors left behind after PDT treatment. Furthermore, such a cancer immunotherapy strategy has a long-term immune memory function to protect treated mice from tumor cell rechallenge. This work presents an immune-stimulating UCNP-based PDT strategy in combination with CTLA-4 checkpoint blockade to effectively destroy primary tumors under light exposure, inhibit distant tumors that can hardly be reached by light, and prevent tumor reoccurrence via the immune memory effect.

Topics: Animals; Cell Line, Tumor; Chlorophyllides; Colonic Neoplasms; Colorectal Neoplasms; CTLA-4 Antigen; Disease Models, Animal; Female; HeLa Cells; Humans; Imiquimod; Immunotherapy; Mice; Mice, Inbred BALB C; Nanoparticles; Photochemotherapy; Photosensitizing Agents; Porphyrins

We synthesized methoxy poly(ethylene glycol) (MPEG)-chlórin e6 (Ce6) conjugates to increase aqueous solubility of Ce6, to fabricate nanoparticles, and to improve tumor targetability of Ce6. MPEG-Ce6 conjugates (abbreviated as Pe6) associated in the aqueous solution as a nanoparticle. Pe6 nanoparticles have small diameter less than 100 nm, spherical shape, and core-shell structure in the aqueous environment. They have improved photophysical properties compared to Ce6 itself. Photosensitivity of Pe6 nanoparticles were studied using HCT116 human colon carcinoma cells. Pe6 nanoparticles practically have no dark-toxicity against HCT116 human colon carcinoma cells while they showed enhanced cellular uptake, phototoxicity, and ROS generation at in vitro cell culture experiment. Furthermore, they showed improved tumor tissue penetration and accumulation in vivo animal studies. We suggested Pe6 nanoparticles as an ideal candidate for PDT of colon cancer.

Topics: Animals; Cell Line, Tumor; Chlorophyllides; Colonic Neoplasms; Humans; Mice; Mice, Nude; Nanoparticles; Photosensitizing Agents; Polyethylene Glycols; Porphyrins; Xenograft Model Antitumor Assays

Long circulating doxorubicin (Dox)-loaded PEGylated liposomes are clinically safer than the free form due to the significant reduction of cardiac toxicity. However, the therapeutic efficacy of the PEGylated liposome could further be improved if poor diffusivity and slow drug release of the liposome in tumor interstitium can be overcome. In this study, a dual-effect liposome triggered by photodynamic effect was developed to improve the therapeutic efficacy of Dox-loaded PEGylated liposomes.. Dox and chlorin e6 (Ce6) were co-encapsulated in PEGylated liposomes (named as PL-Dox-Ce6). To induce the drug release, photodynamic effect was triggered by the light irradiation of a 662 nm diode laser. The cellular distribution of Dox and Ce6 was examined under confocal microscope. The in vitro and in vivo cytotoxicity of PL-Dox-Ce6 was determined via the colony formation assay and the synergistic C26 tumor model, respectively.. The cellular distribution of PL-Dox-Ce6 was in the cytoplasmic area; while under light irradiation, Dox was co-localized with nuclear staining positive signals. The cellular cytotoxicity of PL-Dox-Ce6 was significantly higher than the controls including liposomes encapsulating either Dox (PL-Dox) or Ce6 (PL-Ce6). The in vivo treatment efficacy of PL-Dox-Ce6 determined in the C26 tumor model reveals a significant therapeutic effect compared to that of PL-Ce6 and PL-Dox alone or in combination.. This study indicates that this dual-effect PEGylated liposome could provide clinical advantages in the combination regimen of photodynamic therapy and chemotherapy.

Topics: Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Cell Survival; Chlorophyllides; Colonic Neoplasms; Doxorubicin; Humans; Lasers, Semiconductor; Liposomes; Male; Melanoma; Mice; Mice, Inbred BALB C; Neoplastic Stem Cells; Photochemotherapy; Photosensitizing Agents; Polyethylene Glycols; Porphyrins; Random Allocation; Tumor Stem Cell Assay; Xenograft Model Antitumor Assays

The goal of this study was to develop a strategy for the selective destruction of colorectal cancer cells. Towards this end, photoimmunoconjugates were prepared between the anti-colon cancer monoclonal antibody 17.1A and the photosensitizer (PS) chlorin(e6) (c(e6)). Polylysine linkers bearing several c(e6) molecules were covalently attached in a site-specific manner to partially reduced IgG molecules, which allowed photoimmunoconjugates to bear either cationic or anionic charges. The conjugates retained immunoreactivity as shown by enzyme-linked immunosorbent assays and by competition studies with native antibody. The overall charge on the photoimmunoconjugate was an important determinant of PS delivery. The cationic photoimmunoconjugate delivered 4 times more c(e6) to the cells than the anionic photoimmunoconjugate, and both 17.1A conjugates showed, in comparison to non-specific rabbit IgG conjugates, selectivity for antigen-positive target cells. Illumination with only 3 J cm(-2) of 666 nm light reduced the number of colony forming cells by more than 90% for the cationic 17.1A conjugate and by 73% for the anionic 17.1A conjugate after incubation with 1 microM c(e6) equivalent of the respective conjugates. By contrast, 1 microM free c(e6) gave only a 35% reduction in colonies. These data suggest photoimmunoconjugates may have applications in photoimmunotherapy where destruction of colorectal cancer cells is required.

Topics: Antibodies, Monoclonal; Binding, Competitive; Chlorophyllides; Colonic Neoplasms; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique, Direct; Fluorescent Antibody Technique, Indirect; HT29 Cells; Humans; Immunoconjugates; Immunoglobulin G; Microscopy, Fluorescence; Photochemotherapy; Porphyrins; Radiation-Sensitizing Agents; Temperature

An in vivo study of tissue distribution kinetics and photodynamic therapy (PDT) using 5-aminolaevulinic acid (ALA), chlorin e6 (Chl) and Photofrin (PII) was performed to evaluate the selectivity of porphyrin accumulation and tissue damage effects in a tumour model compared with normal tissue. C26 colon carcinoma of mice transplanted to the foot was used as a model for selectivity assessment. Fluorescence measurements of porphyrin accumulation in the foot bearing the tumour and in the normal foot were performed by the laser-induced fluorescence (LIF) system. A new high-intensity pulsed light delivery system (HIPLS) was used for simultaneous irradiation of both feet by light in the range of 600-800 nm, with light doses from 120 to 300 J cm-2 (0.6 J cm-2 per pulse, 1 Hz). Photoirradiation was carried out 1 h after injection of ALA, 3 h after injection of Chl and 24 h after injection of PII. A ratio of porphyrin accumulation in tumour vs normal tissue was used as an index of accumulation selectivity for each agent. PDT selectivity was determined from the regression analysis of normal and tumour tissue responses to PDT as a function of the applied light dose. A normal tissue damage index was defined at various values (50, 80 and 100%) of antitumour effect. The results of the LIF measurements revealed different patterns of fluorescence intensity in tumour and normal tissues for ALA-induced protoporphyrin IX (ALA-PpIX), Chl and PII. The results of PDT demonstrated the differences in both anti-tumour efficiency and normal tissue damage for the agents used. The selectivity of porphyrin accumulation in the tumour at the time of photoirradiation, as obtained by the LIF measurements, was in the order ALA-PpIX > Chl > PII. PDT selectivity at an equal value of anti-tumour effect was in the order Chl > ALA-PpIX > PII. Histological examination revealed certain differences in structural changes of normal skin after PDT with the agents tested. The results of PDT selectivity assessment with respect to differences in mechanisms of action for ALA, Chl and PII are discussed.

Topics: Aminolevulinic Acid; Animals; Chlorophyllides; Colonic Neoplasms; Dihematoporphyrin Ether; Female; Fluorescence; Mice; Mice, Inbred BALB C; Photochemotherapy; Photosensitizing Agents; Porphyrins; Protoporphyrins; Tissue Distribution