Administration Of 5-aminolevulinic Acid Research Articles

Accumulation of Uroporphyrin I in Necrotic Tissues of Squamous Cell Carcinoma after Administration of 5-Aminolevulinic Acid.

5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence is widely used for the intraoperative detection of malignant tumors. However, the fluorescence emission profiles of the accompanying necrotic regions of these tumors have yet to be determined. To address this, we performed fluorescence and high-performance liquid chromatography (HPLC) analyses of necrotic tissues of squamous cancer after 5-ALA administration. In resected human lymph nodes of metastatic squamous cell carcinoma, we found a fluorescence peak at approximately 620 nm in necrotic lesions, which was distinct from the PpIX fluorescence peak at 635 nm for viable cancer lesions. Necrotic lesions obtained from a subcutaneous xenograft model of human B88 oral squamous cancer also emitted the characteristic fluorescence peak at 620 nm after light irradiation: the fluorescence intensity ratio (620 nm/635 nm) increased with the energy of the irradiation light. HPLC analysis revealed a high content ratio of uroporphyrin I (UPI)/total porphyrins in the necrotic cores of murine tumors, indicating that UPI is responsible for the 620 nm peak. UPI accumulation in necrotic tissues after 5-ALA administration was possibly due to the failure of the heme biosynthetic pathway. Taken together, fluorescence imaging of UPI after 5-ALA administration may be applicable for the evaluation of tumor necrosis.

Adjuvant Photodynamic Therapy, Mediated via Topical Versus Systemic Administration of 5-Aminolevulinic Acid for Control of Murine Mammary Tumor after Surgical Resection.

Treatment de-escalation is sought in the management of precursor lesions of early stage breast cancer, driving the appeal of adjuvant modalities to lumpectomy that reduce toxicity and minimally detract from patient quality of life. We investigate photodynamic therapy (PDT), with the photosensitizing prodrug, 5-aminolevulinic acid (ALA), as adjuvant therapy to complete resection of murine mammary tumor (propagated from TUBO cells). ALA was delivered either systemically (oral, 250 mg kg-1 ) at 5 h before 632 nm illumination or topically (20% solution) to the resection site at 10 min before light delivery to 135 J cm-2 . Treatment with either oral-ALA-PDT (oALA-PDT) or topical-ALA-PDT (tALA-PDT) to the mammary fat pad after TUBO complete resection (CR) produced long-term tumor control with 90-day complete response rates of 21% and 32%, respectively, compared to control rates of 0-5% in mice receiving only CR. Thus, CR/tALA-PDT was equipotent to CR/oALA-PDT despite ~10-fold lower levels of ALA-induced protoporphyrin XI as photosensitizer after topical versus oral-ALA administration. CR/oALA-PDT produced more vascular damage, greater proportion of tissue-resident neutrophils and stronger inflammation when compared to CR/tALA-PDT. Collectively, these data provide rationale for ongoing investigation of ALA-PDT as adjuvant therapy after lumpectomy for increased probability of local control in the treatment of breast cancer.

Fluorescence-Guided Surgery in the Surgical Treatment of Gliomas: Past, Present and Future.

Simple SummaryGliomas are aggressive central nervous system tumours. The emergence and recent widespread adoption of 5-aminolevulinic acid and fluorescence guided surgery have improved the extent of resection, with implications for improved survival and progression-free survival. This review describes the history, rationale and mechanism behind the use of 5-aminolevulinic acid and fluorescence-guided surgery. We also discuss current limitations and future directions for this important adjunct to glioma surgery. This review aims to provide readers with an up-to-date overview and evidence base on this important topic.Gliomas are central nervous systems tumours which are diffusely infiltrative and difficult to treat. The extent of surgical resection is correlated with improved outcomes, including survival and disease-free progression. Cancerous tissue can be directly visualised intra-operatively under fluorescence by administration of 5-aminolevulinic acid to the patient. The adoption of this technique has allowed surgeons worldwide to achieve greater extents of resection, with implications for improved prognosis. However, there are practical limitations to use of 5-aminolevulinic acid. New adjuncts in the field of fluorescence-guided surgery aim to improve recognition of the interface between tumour and brain with the objective of improving resection and patient outcomes.

Oral 5-aminolevulinic acid administration prior to transurethral resection of bladder tumor causes intraoperative hypotension: Propensity score analysis

BackgroundTransurethral resection of bladder tumor (TUR-BT) using 5-aminolevulinic acid (5-ALA) is common; however, intraoperative hypotension is frequent. This study aimed to investigate the impact of preoperative oral 5-ALA taking on hypotension and vasopressors dose during general anesthesia, and postoperative nausea and vomiting. MethodsThis retrospective study included patients aged ≥ 20 years who had undergone elective TUR-BT for bladder tumors under general anesthesia. An inverse probability of treatment weighted using stabilized inverse propensity scores was adopted to minimize bias. After adjustment based on patient data, outcomes of interest in patients with and without preoperative administration of 5-ALA were compared using a generalized estimating equation. Primary outcomes were hypotension incidence during anesthesia, which was defined as a mean arterial pressure < 60 mmHg, and the impact of 5-ALA administration on hypotension. ResultsOf 324 patients considered, 153 (47.2 %) received 5-ALA preoperatively. The weighted incidence of hypotension was 23.3 % in patients taking 5-ALA, with an odds ratio of 4.21 (95 % confidence interval 2.07–8.55). Odds ratios (ORs) and 95 % confidence intervals for oral 5-ALA administration were 1.55 (1.23–1.96) for ephedrine, 1.18 (0.66–2.11) for phenylephrine, and 12.3 (5.73–26.5) for postoperative nausea and vomiting. ConclusionsPreoperative oral 5-ALA administration was associated with hypotension during general anesthesia in patients who underwent TUR-BT despite receiving higher doses of ephedrine. Postoperative nausea and vomiting were also more common in these patients.

The sustaining of fluorescence in photodynamic diagnosis after the administration of 5-aminolevulinic acid in carcinogen-induced bladder cancer orthotopic rat model and urothelial cancer cell lines

BackgroundThe administration of 5-aminolevulic acid hydrochloride (5-ALA·HCl) 3 h (range: 2–4 h) before photodynamic diagnosis (PDD) is recommended for detecting bladder tumors. However, there is insufficient evidence on the time duration for the fluorescence of PDD after oral administration of 5-ALA. We investigated the sustainability of the photodynamic effect and protoporphyrinⅨ (PpⅨ) after 5-ALA administration in a carcinogen-induced bladder tumor rat model and bladder cancer cell lines. MethodsThe carcinogen-induced bladder tumor orthotopic rat model was established by the administration of N-butyl-N-(4-hydroxybutyl) nitrosamine. ResultsRed fluorescence was visible 2–8 h after the oral administration of 5-ALA in the carcinogen-induced bladder tumor rat model. Plasma and intratissue PpⅨ (nM) progressed to a higher level at 2 h and remained almost constant 2–8 h after oral administration of 5-ALA. The peak fluorescence intensity of PpⅨ was observed 3–4 h after the administration of 5-ALA in bladder cancer cell lines. The accumulated PpⅨ remained for 4 h after the removal of 5-ALA in UMUC3 cells. It was not clearly visible 3 h after the removal of 5-ALA in MGHU3 and T24 cells. The expression level of ferrochelatase was significantly lower in UMUC3 cells than in other cells. Our findings suggest that 5-ALA-assisted PDD (ALA-PDD) can aid in detecting non-muscle-invasive bladder cancer 2–8 h after 5-ALA administration. ConclusionUrologists might not be required to make excess effort to start ALA-PDD-assisted transurethral resection of bladder tumor after the administration of 5-ALA.

Sublingual administration of 5-aminolevulinic acid for laser-induced photodiagnostics and photodynamic therapy of oral cavity and larynx cancers

BackgroundThe study aimed to develop a method for sublingual administration of 5-aminolevulinic acid to patients and evaluate its effectiveness in fluorescence diagnostics and photodynamic therapy of neoplasms of the oral cavity and larynx. MethodsThe boundaries of the neoplasms were established by the video-fluorescence diagnostics and clarified using spectral-fluorescent diagnosis before and after photodynamic therapy. ResultsThe fluorescence diagnostics demonstrated a high accumulation of protoporphyrin IX, induced by sublingual administration of 5-aminolevulinic acid to patients before the photodynamic therapy and photobleaching of protoporphyrin IX in pathologically altered tissues after the photodynamic therapy. Glucose contained in the sublingual dose supports active transport of 5-ALA into the cells. It increases the PpIX accumulation in the cells, therefore improving the PD and PDT efficacy. ConclusionThe study and the initially obtained results demonstrated the possibility and effectiveness of laser-induced photodiagnostics and photodynamic therapy with sublingual administration of 5-ALA to patients with premalignant lesions of the oral cavity and larynx. It can eliminate the threat of the transformation of these diseases into malignant tumors and prevent the need for surgical treatment.

Standardized intraoperative 5-ALA photodynamic therapy for newly diagnosed glioblastoma patients: a preliminary analysis of the INDYGO clinical trial

Glioblastoma (GBM) is the most aggressive malignant primary brain tumor. The unfavorable prognosis despite maximal therapy relates to high propensity for recurrence. Thus, overall survival (OS) is quite limited and local failure remains the fundamental problem. Here, we present a safety and feasibility trial after treating GBM intraoperatively by photodynamic therapy (PDT) after 5-aminolevulinic acid (5-ALA) administration and maximal resection. Ten patients with newly diagnosed GBM were enrolled and treated between May 2017 and June 2018. The standardized therapeutic approach included maximal resection (near total or gross total tumor resection (GTR)) guided by 5-ALA fluorescence-guided surgery (FGS), followed by intraoperative PDT. Postoperatively, patients underwent adjuvant therapy (Stupp protocol). Follow-up included clinical examinations and brain MR imaging was performed every 3months until tumor progression and/or death. There were no unacceptable or unexpected toxicities or serious adverse effects. At the time of the interim analysis, the actuarial 12-months progression-free survival (PFS) rate was 60% (median 17.1months), and the actuarial 12-months OS rate was 80% (median 23.1months). This trial assessed the feasibility and the safety of intraoperative 5-ALA PDT as a novel approach for treating GBM after maximal tumor resection. The current standard of care remains microsurgical resection whenever feasible, followed by adjuvant therapy (Stupp protocol). We postulate that PDT delivered immediately after resection as an add-on therapy of this primary brain cancer is safe and may help to decrease the recurrence risk by targeting residual tumor cells in the resection cavity. Trial registration NCT number: NCT03048240. EudraCT number: 2016-002706-39.

Peptide-targeted dendrimeric prodrugs of 5-aminolevulinic acid: A novel approach towards enhanced accumulation of protoporphyrin IX for photodynamic therapy

Photodynamic therapy (PDT) is a promising approach for the targeted treatment of cancer and various other human disorders. An effective, clinically approved approach in PDT involves the administration of 5-aminolevulinic acid (ALA) to generate elevated levels of the natural photosensitiser protoporphyrin IX (PpIX). The development of prodrugs of ALA is of considerable interest as a means to enhance the efficiency and cell selectivity of PpIX accumulation for PDT applications. In this work a novel peptide-targeted dendrimeric prodrug of 5-aminolevulinic acid (ALA) 13 was synthesised which displays nine copies of ALA on a core structure that is linked to a homing peptide for targeted delivery to a specific cancer cell type. The synthesis was accomplished effectively via a flexible, modular solid phase and solution phase route, using a combination of solid phase peptide synthesis and copper-catalysed azide-alkyne cycloaddition chemistry. The prodrug system shows a sustained and enhanced production of protoporphyrin IX (PpIX) in the MDA-MB-231 cell line that over-expresses the epidernal growth factor receptor (EGFR+) in comparison to equimolar ALA and the corresponding non-targeted ALA dendrimer (nine copies of ALA). This study provides a proof of concept for the development of a new generation of prodrugs for ALA-based photodynamic therapy that can deliver an enhanced ALA payload to specific tissue types.

Impact of age, body mass index, and renal function for severe hypotension caused by oral 5-aminolevulinic acid administration in patients undergoing transurethral resection of bladder tumor.

Severe hypotension is a notable adverse event caused by administration of 5-aminolevulinic acid (5-ALA) during photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT). Hypotension can be prolonged following induction of anesthesia and may require continuous administration of a vasopressor. Here, we investigated the risk factors for severe hypotension caused by oral administration of 5-ALA. A total of 128 patients with bladder tumors who underwent PDD-TURBT using 5-ALA were included in this study. Clinicopathological data were collected retrospectively and the correlations between the incidence of severe hypotension and clinicopathological factors were analyzed. Severe hypotension developed in 8 cases (6.3 %). Age ≥ 80 years, body mass index (BMI) ≥ 25 (kg/m2), and estimated glomerular filtration rate (eGFR) < 45 (mL/min/1.73 m2) were significantly correlated with severe hypotension (P = 0.003, 0.017, and 0.027, respectively). Severe hypotension developed in 1 of 89 cases (1.1 %) which have 0 or 1 risk factor, and in 3 of 31 cases (9.7 %) which have 2 risk factors, whereas it developed in 4 of 8 cases (50 %) which have all risk factors. Patients with all risk factors developed severe hypotension significantly more frequently compared with patients with 1 or fewer risk factors (P < 0.001). Age ≥ 80 years, BMI ≥ 25, and eGFR < 45 are risk factors for severe hypotension in PDD-TURBT using 5-ALA. The risk of developing severe hypotension is extremely high in patients who have all factors. Adjustment of the 5-ALA dose may be desirable in those patients.

Key transporters leading to specific protoporphyrin IX accumulation in cancer cell following administration of aminolevulinic acid in photodynamic therapy/diagnosis.

The administration of aminolevulinic acid allow the formation and accumulation of protoporphyrin IX specifically in cancer cells, which then lead to photocytotoxicity following light irradiation. This compound, when accumulated at high levels, could also be used in cancer diagnosis as it would emit red fluorescence when being light irradiated. The concentration of protoporphyrin IX is pivotal in ensuring the effectiveness of the therapy. Studies have been carried out and showed the importance of various transporters in regulating the amount of these substrates by controlling the transport of various related metabolites in and out of the cell. There are many transporters involved and their expression levels are dependent on various factors, such as oxygen availability and iron ions. It is also important to note that these transporters may also have different expression levels depending on their organ. Understanding the mechanisms and the roles of these transporters are essential to ensure maximum accumulation of protoporphyrin IX, leading to higher efficiency in photodynamic therapy/diagnosis. In this review, we would like to discuss the roles of various transporters in protoporphyrin IX accumulation and how their involvement directly affect cancerous microenvironment.

Effectiveness of Photodynamic Screening Using 5-Aminolevulinic Acid for the Diagnosis of Pancreatic Cancer.

We evaluated urinary levels of porphyrin metabolites, such as uroporphyrin (UP) and coproporphyrin (CP), after 5-Aminolevulinic acid (ALA) administration in patients with or without pancreatic cancer (PaC). Sixty-seven subjects with PaC, 11 with pancreatitis, and 9 with normal pancreas (NP) were enrolled. Urine samples from all subjects were collected prior to ALA administration and at more than 4 hours after ALA administration. We measured the urinary levels of UP and CP by high-performance liquid chromatography analysis. The PaC group showed significantly higher UP levels compared to NP groups (104.9 nmol/g Cre vs. 53.4 nmol/g Cre, p=0.014). Moreover, PaC patients with long-term survival had significantly lower urinary levels of UP at diagnosis (98.8 nmol/gCre) than the short-term survival group (125.2 nmol/gCre) (p=0.042). The urinary levels of UP after ALA administration might serve as a promising biomarker for diagnosis and prognosis prediction of PaC.

In Vivo-like model of glial tumors: Creation of primary cell lines.

e14515 Background: The choice of cell source for 3D bioprinting of in vivo-like models of glial tumors is crucial and must take into account the ability to proliferation and stable metabolism. Oral administration of 5-aminolevulinic acid (5-ALA) in patients prior to surgery increases the fluorescent contrast between tumor and surrounding tissue, but the effect of contrast agents on cells in vitro is unknown. The aim of the study was obtaining viable glial tumor tissues using 5-ALA, as well as the development of a stable primary cell culture for 3D bioprinting. Methods: Tumor tissue was obtained from patients with glioblastoma during surgery under visual control using the Opmi Pentero Blue E400 microscope and 5-ALA. Material was disaggregated on a BD Machine using Medicons 50 μm (BD). Glioblastoma cells were cultured in DMEM/F12 medium with L-glutamine (Gibco) containing 10% fetal bovine serum (Biolot, Russia), 1% non-essential amino acids (NEAA, Sigma-Aldrich) and 0.5% penicillin-streptomycin (Biolot) at 37C. Glial cell lines were characterized immunohistochemically using antibodies to the glial fibrillary acidic protein (GFAP) and proliferation index (Ki-67). Microsatellite analysis was performed using three dinucleotide repeat markers D2S123, D17S250, D5S346 and five mononucleotide loci BAT25, BAT26, NR21, NR24 and NR27. Results: The positive expression of GFAP on the cell processes of the star-like shape was clearly visualized, indicating a morphological feature of glial tumors. The Ki-67 labeling index was 70%. Changes were observed at the D17S250 locus (148-148/148-152) for the glial tumor primary cells after the sixth passage. Microsatellite instability was not observed in the primary cell culture. Conclusions: The accumulation of porphyrins from 5-ALA in glial tumor cells does not prevent the in vitro creation of a cell culture from tumor tissue. Microsatellite analysis showed that the obtained glioblastoma cell lines remain stable for at least 10 passages. Material obtained during resection using 5-ALA is a reliable source of stable glial tumor cell lines.

Real-time in vivo kinetics of protoporphyrin IX after administration of 5-aminolevulinic acid in meningiomas and comparative analyses with glioblastomas.

The usefulness of 5-aminolevulinic acid (5-ALA)-mediated fluorescence-guided surgery (FGS) in meningiomas is intensely discussed. However, data about kinetics of 5-ALA and protoporphyrin (Pp) IX in meningiomas are lacking. As the first study so far, we performed longitudinal intraoperative real-time ex situ measurements of fluorescence intensity and PpIX concentrations during FGS of ten benign and two atypical meningiomas. Kinetics were subsequently compared with data from 229 glioblastomas. Spectroscopy revealed fluorescence (median 2945.65a.u.) and PpIX accumulation (median 18.31μg/ml) in all 43 analyzed samples. Fluorescence intensity (2961.50a.u. vs 118.41a.u.; p < .001) and PpIX concentrations (18.72μg/ml vs .98μg/ml; p < .001) were higher in samples with (N = 30) than without (N = 2) visible intraoperative tumor fluorescence. ROC curve analyses revealed a PpIX cut-off concentration of 3.85μg/ml (AUC = .992, p = .005) and a quantitative fluorescence cut-off intensity of 286.73a.u. (AUC = .983, p = .006) for intraoperative visible tumor fluorescence. Neither fluorescence intensity (p = .356) nor PpIX (p = .631) differed between atypical and benign meningiomas. Fluorescence and PpIX peaked 7-8h following administration of 5-ALA. Meningiomas displayed a higher fluorescence intensity (p = .012) and PpIX concentration (p = .005) than glioblastomas 5-6h after administration of 5-ALA. Although fluorescence was basically maintained, PpIX appeared to be cleared faster in meningiomas than in glioblastomas. Kinetics of PpIX and fluorescence intensity differ between meningiomas and glioblastomas in the early phase after 5-ALA administration. Modification of the timing of drug administration might impact visibility of intraoperative fluorescence and helpfulness of FGS and should be investigated in future analyses.

Effectiveness of a single treatment of photodynamic therapy using topical administration of 5-aminolevulinic acid on methicillin-resistant Staphylococcus aureus-infected wounds of diabetic mice

Methicillin-resistant Staphylococcus aureus (MRSA) is the most important representative pathogen which causes clinically relevant infections in diabetic ulceration. We report our investigations on the efficacy of antimicrobial photodynamic therapy with topical 5-aminolevulinic acid (ALA-PDT) on diabetic murine infected wound models induced with a MRSA SA325 strain. A solution of 10 % 5-aminolevulinic acid (ALA) was placed into the wounds followed by delivery of 25 J/cm2 (635 nm). The ALA-PDT treated wounds healed earlier as compared to others (P < 0.5). A significant reduction of bacterial counts (2.05 logs) was detected in wounds after ALA-PDT on Day 2 (P < 0.5). Additionally, histological analysis revealed that wounds treated with ALA-PDT exhibited a more complete re-epithelialization, blood micro-vessels, collagen-volume fraction and considerable decrease in inflammatory cells infiltration. Immunohistochemistry assay demonstrated considerable reduction of proinflammatory cytokines interleukin-1β (IL-1β), earlier expression of vascular endothelial growth factor A (VEGF-A), increase of basic fibroblast growth factor (bFGF) and Ki-67 in the ALA-PDT group (P < 0.5). These data imply that the therapeutic effect of ALA-PDT revealed an accelerated diabetic wound closure rate, together with reduced hyperinflammatory response and elevated growth factors.

MP72-09 INTRAOPERATIVE HYPOTENSION CAUSED BY ORAL ADMINISTRATION OF 5-AMINOLEVULINIC ACID FOR PHOTODYNAMIC DIAGNOSIS IN PATIENTS WITH BLADDER CANCER

INTRODUCTION AND OBJECTIVE:The patients in some instances experienced hypotension after the oral administration of 5-aminolevulinic acid. In this study, we analyzed the pre- and intraoperative bloo...

Stimulation of the oxygen consumption by photobiomodulation in the chicken embryo chorioallantoic membrane during hypoxia

AbstractThe main objective of this project is to study the effects of photobiomodulation (PBM) on the oxygen consumption in the in vivo chick's embryo chorioallantoic membrane (CAM) under hypoxia to improve understanding of the mechanisms involved in PBM therapy of various conditions, including strokes and ischemic wounds. Protoporphyrin IX (PPIX), produced endogenously after administration of aminolevulinic acid, was used to probe the oxygen partial pressure (pO2) in the CAM by time‐resolved spectroscopy of its delayed fluorescence. This approach enables exploring and optimizing conveniently different radiometric and spectral parameters at play in PBM. Interestingly, as PPIX is produced in the mitochondria, an organelle playing a key role in cell respiration, and then diffuses in different compartments, the pO2 can be determined in different (sub‐) cellular/tissue locations. Our results showed that PBM applied between 6 and 16 minutes (5 mW/cm2) after the beginning of hypoxia with light at 730 or 820 nm sustains the oxygen consumption in the CAM for more than one hour, an effect that is not observed in control eggs. This may explain the positive effects induced by PBM in hypoxic tissues, including those that are subject to ischemia‐reperfusion injuries.

5-aminolevulinic acid inhibits oxidative stress and ameliorates autistic-like behaviors in prenatal valproic acid-exposed rats

Autism spectrum disorders (ASDs) constitute a neurodevelopmental disorder characterized by social deficits, repetitive behaviors, and learning disability. Oxidative stress and mitochondrial dysfunction are associated with ASD brain pathology. Here, we used oxidative stress in prenatal valproic acid (VPA)-exposed rats as an ASD model. After maternal VPA exposure (600 mg/kg, p.o.) on embryonic day (E) 12.5, temporal analyses of oxidative stress in the brain using an anti-4-hydroxy-2-nonenal antibody revealed that oxidative stress was increased in the hippocampus after birth. This was accompanied by aberrant enzymatic activity in the mitochondrial electron transport chain and reduced adenosine triphosphate (ATP) levels in the hippocampus. VPA-exposed rats exhibited impaired spatial reference and object recognition memory alongside impaired social behaviors and repetitive behaviors. ASD-like behaviors including learning and memory were rescued by chronic oral administration of 5-aminolevulinic acid (5-ALA; 30 mg/kg/day) and intranasal administration of oxytocin (OXT; 12 μg/kg/day), a neuropeptide that improves social behavior in ASD patients. 5-ALA but not OXT treatment ameliorated oxidative stress and mitochondrial dysfunction in the hippocampus of VPA-exposed rats. Fewer parvalbumin-positive interneurons were observed in VPA-exposed rats. Both 5-ALA and OXT treatments augmented the number of parvalbumin-positive interneurons. Collectively, our results indicate that oral 5-ALA administration ameliorated oxidative stress and mitochondrial dysfunction, suggesting that 5-ALA administration improves ASD-like neuropathology and behaviors via mechanisms different to those of OXT.

Metabolism-based isolation of invasive glioblastoma cells with specific gene signatures and tumorigenic potential.

BackgroundGlioblastoma (GBM) is a highly aggressive brain tumor with rapid subclonal diversification, harboring molecular abnormalities that vary temporospatially, a contributor to therapy resistance. Fluorescence-guided neurosurgical resection utilizes the administration of 5-aminolevulinic acid (5-ALA) generating individually fluorescent tumor cells within a background population of non-neoplastic cells in the invasive tumor region. The aim of the study was to specifically isolate and interrogate the invasive GBM cell population using a novel 5-ALA-based method.MethodsWe have isolated the critical invasive GBM cell population by developing 5-ALA-based metabolic fluorescence-activated cell sorting. This allows purification and study of invasive cells from GBM without an overwhelming background “normal brain” signal to confound data. The population was studied using RNAseq, real-time PCR, and immunohistochemistry, with gene targets functionally interrogated on proliferation and migration assays using siRNA knockdown and known drug inhibitors.ResultsRNAseq analysis identifies specific genes such as SERPINE1 which is highly expressed in invasive GBM cells but at low levels in the surrounding normal brain parenchyma. siRNA knockdown and pharmacological inhibition with specific inhibitors of SERPINE1 reduced the capacity of GBM cells to invade in an in vitro assay. Rodent xenografts of 5-ALA-positive cells were established and serially transplanted, confirming tumorigenicity of the fluorescent patient-derived cells but not the 5-ALA-negative cells.ConclusionsIdentification of unique molecular features in the invasive GBM population offers hope for developing more efficacious targeted therapies compared to targeting the tumor core and for isolating tumor subpopulations based upon intrinsic metabolic properties.

5-Aminolevulinic acid photoactivated over planktonic and biofilm forms of Enterococcus faecalis as a pharmacological therapy alternative

The purpose of the study was to evaluate the antibacterial effect of protoporphyrin IX (PpIX) generated by the exogenous administration of 5-aminolevulinic acid or δ-ALA and activated with an argon laser over a planktonic and biofilm of Enterococcus faecalis (E. faecalis) as a pharmacological therapy alternative. A planktonic strain of E. faecalis was cultured with a solution of ∂-ALA (40 µg/mL)-thioglycolate solution for 13 min, and a biofilm of E. faecalis was cultured in a δ-ALA (80 µg/mL)-thioglycolate solution for 13 min. Then, both were irradiated with an argon laser. Finally, the antibacterial effect was evaluated by counting the CFU in planktonic form, and a LIVE/DEAD viability cell test. The production and accumulation of PpIX from exogenously administered δ-ALA on E. faecalis in planktonic and biofilm forms was confirmed by spectrofluorometry. The irradiation of PpIX with an argon laser produced an antibacterial effect on E. faecalis in planktonic and biofilm form, even without biofilm disruption, at a concentration of 40 µg/mL and 80 µg/mL of δ-ALA, respectively. The exogenous administration of δ-ALA in combination with laser irradiation on planktonic and biofilm forms of E. faecalis produces an effective antibacterial effect as complement or alternative to pharmacological therapies.

Role of iron metabolism in the immunosuppression mediated by myeloid cells in glioblastoma patients

Abstract Background Glioblastoma multiforme (GBM) is one of the most malignant primary brain tumor and is known to create an immunosuppressive microenvironment that hampers the efficacy of therapies. We demonstrated that GBM microenvironment is infiltrated with a large proportion of bone marrow-derived macrophages (BMDMs) that possess a strong immune suppressive activity. Following 5-aminolevulinic acid (5-ALA) administration to patients before surgery, BMDMs show the highest protoporphyrin IX (PPIX) fluorescence emission, compared to immune and non-immune cells. Since PPIX is the precursor of heme we wondered if the presence of this metabolite could be the consequence of an altered iron metabolism in BMDMs, and if this pathway could be linked to their immunosuppressive activity. Methods GBM tissues were dissociated and subjected to immunomagnetic or FACS sorting for the separation of BMDMs. The expression of HMOX1, the gene coding for heme oxygenase-1 (HO-1) which is a central enzyme in the iron pathway, was analyzed by RT-PCR. BMDM immune suppressive activity was evaluated as the ability to suppress the proliferation of T lymphocytes also in the presence of HO-1 inhibitors. In order to optimize the experimental conditions, immunosuppressive macrophages derived from M-CSF treated monocytes from healthy donors were set up. Another in vitro model of immunosuppressive cells, bone marrow derived-myeloid derived suppressor cells (BM-MDSCs), was tested. Results HMOX1 expression was found to be upregulated in BMDMs compared to other cells. The treatment of BMDMs with a HO-1 inhibitor was able to restore T cells proliferation in immune suppressive assays. The recovery of immunosuppression following treatment with the inhibitor has also been demonstrated in macrophages and in BM-MDSCs. Conclusion Our results show that the connection between iron metabolism and immune response could be exploited from a therapeutic point of view. In particular, HO-1 plays a role in BMDM-induced immunosuppression and could represent a new target to relieve the immunosuppressive microenvironment present in GBM patients. Legal entity responsible for the study University of Padua. Funding AIRC. Disclosure All authors have declared no conflicts of interest.