Metformin enhances the cytotoxicity of 5-aminolevulinic acid-mediated photodynamic therapy in vitro.
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ABSTRACT:
SUBMITTER: Osaki T
PROVIDER: S-EPMC5494612 | biostudies-other | 2017 Jul
REPOSITORIES: biostudies-other
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Project description:BackgroundCancerous cells usually exhibit increased aerobic glycolysis, compared with normal tissue (the Warburg effect), making this pathway an attractive therapeutic target.MethodsCell viability, cell number, clonogenic assay, reactive oxygen (ROS), ATP, and apoptosis were assayed in MCF-7 tumour cells and corresponding primary human mammary epithelial cells (HMEC).ResultsCombining the glycolysis inhibitors 2-deoxyglucose (2DG; 180 mM) or lonidamine (300 ?M) with 10 J cm(-2) 5-aminolevulinic acid (ALA) photodynamic therapy (PDT) increases MCF-7 cytotoxicity (by 3.5-fold to 70% death after 24 h, and by 10-fold in 9-day clonogenic assays). However, glycolysis inhibition only slightly increases HMEC PDT cytotoxicity (between two-fold and three-fold to a maximum of 9% death after 24 h). The potentiation of PDT cytotoxicity only occurred if the glycolysis inhibitors were added after ALA incubation, as they inhibited intracellular accumulation of photosensitiser if coincubated with ALA.ConclusionAs 2DG and lonidamine are already used as cancer chemotherapeutic agents, our results are directly translatable to combination therapies with existing topical PDT.
| S-EPMC3749566 | biostudies-literature
Project description:BackgroundProtoporphyrin IX (PpIX) gets accumulated preferentially in 5-aminolevulinic acid (5-ALA)-treated cancer cells. Photodynamic therapy (PDT) utilises the accumulated PpIX to trigger cell death by light-induced generation of reactive oxygen species (ROS). We previously demonstrated that oncogenic Ras/MEK decreases PpIX accumulation in cancer cells. Here, we investigated whether combined therapy with a MEK inhibitor would improve 5-ALA-PDT efficacy.MethodsCancer cells and mice models of cancer were treated with 5-ALA-PDT, MEK inhibitor or both MEK inhibitor and 5-ALA-PDT, and treatment efficacies were evaluated.ResultsRas/MEK negatively regulates the cellular sensitivity to 5-ALA-PDT as cancer cells pre-treated with a MEK inhibitor were killed more efficiently by 5-ALA-PDT. MEK inhibition promoted 5-ALA-PDT-induced ROS generation and programmed cell death. Furthermore, the combination of 5-ALA-PDT and a systemic MEK inhibitor significantly suppressed tumour growth compared with either monotherapy in mouse models of cancer. Remarkably, 44% of mice bearing human colon tumours showed a complete response with the combined treatment.ConclusionWe demonstrate a novel strategy to promote 5-ALA-PDT efficacy by targeting a cell signalling pathway regulating its sensitivity. This preclinical study provides a strong basis for utilising MEK inhibitors, which are approved for treating cancers, to enhance 5-ALA-PDT efficacy in the clinic.
| S-EPMC6889170 | biostudies-literature
Project description:Recurrence of glioma frequently occurs within the marginal area of the surgical cavity due to invading residual cells. 5-Aminolevulinic acid (5-ALA) fluorescence-guided resection has been used as effective therapeutic modalities to improve discrimination of brain tumour margins and patient prognosis. However, the marginal areas of glioma usually show vague fluorescence, which makes tumour identification difficult, and the applicability of 5-ALA-based photodynamic therapy (PDT) is hampered by insufficient therapeutic efficacy in glioma tissues.To overcome these issues, we assessed the expression of ferrochelatase (FECH) gene, which encodes a key enzyme that catalyses the conversion of protoporphyrin IX (PpIX) to heme, in glioma surgical specimens and manipulated FECH in human glioma cell lines.Prominent downregulation of FECH mRNA expression was found in glioblastoma tissues compared with normal brain tissues, suggesting that FECH is responsible for PpIX accumulation in glioblastoma cells. Depletion of FECH by small interference RNA enhanced PpIX fluorescence after exposure to 5-ALA concomitant with increased intracellular PpIX accumulation in glioma cells. Silencing of FECH caused marked growth inhibition and apoptosis induction by PDT in glioma cells.These results suggest that knockdown of FECH is a potential approach to enhance PpIX fluorescent quality for optimising the subjective discrimination of vague fluorescence and improving the effect of 5-ALA-PDT.
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Project description:Aspergillus fumigatus biofilm development results in enhanced pathogenicity and treatment resistance. Most contemporary antibiotics, however, are unable to eliminate biofilms. In recent years, with the application of new photosensitizers and the development of treatment, ALA-PDT (5-aminolevulinic acid photodynamic treatment) has achieved remarkable curative effect in the treatment of fungal infectious diseases; however, no research has been conducted on ALA-PDT against A. fumigatus. This study investigated the inhibitory effect of ALA-PDT at various 5-aminolevulinic acid concentrations and light doses on A. fumigatus planktonic and biofilms in vitro. We found that ALA-PDT may successfully inhibit the development of A. fumigatus biofilm and disintegrate mature biofilm. After ALA-PDT treatment, the adherence rate and vitality dramatically decreased, and the biofilm's structure was severely compromised. Our findings show for the first time that ALA-PDT may be used to prevent the formation of A. fumigatus biofilm and disturb the structure of mature biofilm, and that it could be employed as a therapeutic therapy for A. fumigatus superficial infection.
| S-EPMC10474982 | biostudies-literature
Project description:Background5-Aminolevulinic acid (5-ALA), a fluorescent contrast agent, has been used for tumor paint and photodynamic therapy (PDT) for various tumors, but its use with soft tissue sarcomas is not well documented. Myxofibrosarcoma, a subtype of soft tissue sarcoma with a high local recurrence rate, may benefit from similar types of treatment. The purpose of this study was to analyze the effects of 5-ALA tumor paint and PDT on a myxofibrosarcoma cell line.MethodsTumor paint was assessed by exposing micromass pellets of human adipose-derived stromal (ADS) cells or myxofibrosarcoma (MUG-Myx1) cells to 5-ALA. Cell pellets were then visualized using a microscope at established excitation and emission wavelengths. Corrected total cell fluorescence was calculated per accepted protocols. Photodynamic therapy was similarly assessed by exposing ADS and MUG-Myx1 cells to 5-ALA, with subsequent analysis via flow cytometry and real-time confocal microscopy.ResultsThe use of 5-ALA tumor paint led to a selective fluorescence in MUG-Myx1 cells. Findings were confirmed by flow cytometry. Interestingly, flow cytometry results showed progressive selective cell death with increasing 5-ALA exposure as a result of the PDT effect. PDT was further confirmed using confocal microscopy, which revealed progressive cellular bubble formation consistent with advancing stages of cell death-a finding that was not seen in control ADS cells.Conclusions5-ALA tumor paint and PDT were successfully used on a human myxofibrosarcoma cell line (MUG-Myx1). Results from this study showed both selective fluorescent tagging and selective cytotoxicity of 5-ALA toward malignant myxofibrosarcoma cells, while sparing benign adipose control cells. This finding was further confirmed in a dramatic time-lapse video, visually confirming active, targeted cell death. 5-ALA's two-pronged application of selective tumor identification and cytotoxicity may transform surgical and medical approaches for treating soft tissue sarcomas.
| S-EPMC7059315 | biostudies-literature
Project description:5-Aminolevulinic acid (5-ALA), a commonly used photosensitizer in photodynamic detection (PDD) and therapy (PDT), is converted in situ to the established photosensitizer protoporphyrin IX (PpIX) via the heme biosynthetic pathway. To extend 5-ALA-PDT application, we evaluated the PpIX fluorescence induced by exogenous 5-ALA in various veterinary tumors and treated canine and feline tumors. 5-ALA-PDD sensitivity and specificity in the whole sample group for dogs and cats combined were 89.5 and 50%, respectively. Notably, some small tumors disappeared upon 5-ALA-PDT. Although single PDT application was not curative, repeated PDT+/-chemotherapy achieved long-term tumor control. We analyzed the relationship between intracellular PpIX concentration and 5-ALA-PDT in vitro cytotoxicity using various primary tumor cells and determined the correlation between intracellular PpIX concentration and 5-ALA transporter and metabolic enzyme mRNA expression levels. 5-ALA-PDT cytotoxicity in vitro correlated with intracellular PpIX concentration in carcinomas. Ferrochelatase mRNA expression levels strongly negatively correlated with PpIX accumulation, representing the first report of a correlation between mRNA expression related to PpIX accumulation and PpIX concentration in canine tumor cells. Our findings suggested that the results of 5-ALA-PDD might be predictive for 5-ALA-PDT therapeutic effects for carcinomas, with 5-ALA-PDT plus chemotherapy potentially increasing the probability of tumor control in veterinary medicine.
| S-EPMC6520946 | biostudies-literature
Project description:INTRODUCTION:Photodynamic therapy (PDT) is a two-step treatment involving the administration of a photosensitive agent followed by its activation at a specific light wavelength for targeting of tumor cells. MATERIALS/METHODS:A comprehensive review of the literature was performed to analyze the indications for PDT, mechanisms of action, use of different photosensitizers, the immunomodulatory effects of PDT, and both preclinical and clinical studies for use in high-grade gliomas (HGGs). RESULTS:PDT has been approved by the United States Food and Drug Administration (FDA) for the treatment of premalignant and malignant diseases, such as actinic keratoses, Barrett's esophagus, esophageal cancers, and endobronchial non-small cell lung cancers, as well as for the treatment of choroidal neovascularization. In neuro-oncology, clinical trials are currently underway to demonstrate PDT efficacy against a number of malignancies that include HGGs and other brain tumors. Both photosensitizers and photosensitizing precursors have been used for PDT. 5-aminolevulinic acid (5-ALA), an intermediate in the heme synthesis pathway, is a photosensitizing precursor with FDA approval for PDT of actinic keratosis and as an intraoperative imaging agent for fluorescence-guided visualization of malignant tissue during glioma surgery. New trials are underway to utilize 5-ALA as a therapeutic agent for PDT of the intraoperative resection cavity and interstitial PDT for inoperable HGGs. CONCLUSION:PDT remains a promising therapeutic approach that requires further study in HGGs. Use of 5-ALA PDT permits selective tumor targeting due to the intracellular metabolism of 5-ALA. The immunomodulatory effects of PDT further strengthen its use for treatment of HGGs and requires a better understanding. The combination of PDT with adjuvant therapies for HGGs will need to be studied in randomized, controlled studies.
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Project description:Photodynamic therapy (PDT) is an emerging treatment for various solid cancers. We recently reported that tumor cell lines and patient specimens from adult T cell leukemia/lymphoma (ATL) are susceptible to specific cell death by visible light exposure after a short-term culture with 5-aminolevulinic acid, indicating that extracorporeal photopheresis could eradicate hematological tumor cells circulating in peripheral blood. As a bridge from basic research to clinical trial of PDT for hematological malignancies, we here examined the efficacy of ALA-PDT on various lymphoid malignancies with circulating tumor cells in peripheral blood. We also examined the effects of ALA-PDT on tumor cells before and after conventional chemotherapy. With 16 primary blood samples from 13 patients, we demonstrated that PDT efficiently killed tumor cells without influencing normal lymphocytes in aggressive diseases such as acute ATL. Importantly, PDT could eradicate acute ATL cells remaining after standard chemotherapy or anti-CCR4 antibody, suggesting that PDT could work together with other conventional therapies in a complementary manner. The responses of PDT on indolent tumor cells were various but were clearly depending on accumulation of protoporphyrin IX, which indicates the possibility of biomarker-guided application of PDT. These findings provide important information for developing novel therapeutic strategy for hematological malignancies.
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Project description:Neurofibromatosis type 1 (NF1) is one of the most common neurocutaneous disorders. Some NF1 patients develop benign large plexiform neurofibroma(s) at birth, which can then transform into a malignant peripheral nerve sheath tumor (MPNST). There is no curative treatment for this rapidly progressive and easily metastatic neurofibrosarcoma. Photodynamic therapy (PDT) has been developed as an anti-cancer treatment, and 5-aminolevulinic (ALA) mediated PDT (ALA-PDT) has been used to treat cutaneous skin and oral neoplasms. Doxycycline, a tetracycline derivative, can substantially reduce the tumor burden in human and animal models, in addition to its antimicrobial effects. The purpose of this study was to evaluate the effect and to investigate the mechanism of action of combined doxycycline and ALA-PDT treatment of MPNST cells. An 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that the combination of ALA-PDT and doxycycline significantly reduce MPNST survival rate, compared to cells treated with each therapy alone. Isobologram analysis showed that the combined treatment had a synergistic effect. The increased cytotoxic activity could be seen by an increase in cellular protoporphyrin IX (PpIX) accumulation. Furthermore, we found that the higher retention of PpIX was mainly due to increasing ALA uptake, rather than activity changes of the enzymes porphobilinogen deaminase and ferrochelatase. The combined treatment inhibited tumor growth in different tumor cell lines, but not in normal human Schwann cells or fibroblasts. Similarly, a synergistic interaction was also found in cells treated with ALA-PDT combined with minocycline, but not tetracycline. In summary, doxycycline can potentiate the effect of ALA-PDT to kill tumor cells. This increased potency allows for a dose reduction of doxycycline and photodynamic radiation, reducing the occurrence of toxic side effects in vivo.
| S-EPMC5448821 | biostudies-literature
Project description:BackgroundMelanoma therapy is challenging, especially in advanced cases, due to multiple developed tumor defense mechanisms. Photodynamic therapy (PDT) might represent an adjuvant treatment, because of its bimodal action: tumor destruction and immune system awakening. In this study, a combination of PDT mediated by a metal substituted phthalocyanine-Gallium phthalocyanine chloride (GaPc) and Metformin was used against melanoma. The study aimed to: (1) find the anti-melanoma efficacy of GaPc-PDT, (2) assess possible beneficial effects of Metformin addition to PDT, (3) uncover some of the mechanisms underlining cell killing and anti-angiogenic effects.MethodsTwo human lightly pigmented melanoma cell lines: WM35 and M1/15 subjected to previous Metformin exposure were treated by GaPc-PDT. Cell viability, death mechanism, cytoskeleton alterations, oxidative damage, were assessed by means of colorimetry, flowcytometry, confocal microscopy, spectrophotometry, ELISA, Western Blotting.ResultsGaPc proved an efficient photosensitizer. Metformin addition enhanced cell killing by mechanisms dependent on the cell line, namely apoptosis in the metastatic M1/15 and necrosis in the radial growth phase, WM35. Cell death mechanism relied on the inhibition of nuclear transcription factor (NF)-κB activation and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) sensitization, leading to TRAIL and TNF-α induced apoptosis. Metformin diminished the anti-angiogenic effect of PDT.ConclusionsMetformin addition to GaPc-PDT increased tumor cell killing through enhanced oxidative damage and induction of proapoptotic mechanisms, but altered PDT anti-angiogenic effects.General significanceCombination of Metformin and PDT might represent a solution to enhance the efficacy, leading to a potential adjuvant role of PDT in melanoma therapy.
| S-EPMC5344368 | biostudies-literature