F8-SIP mediated targeted photodynamic therapy leads to microvascular dysfunction and reduced glioma growth

Globus Lucidus: A porcine study of an intracranial implant designed to deliver closed, repetitive photodynamic and photochemical therapy in glioblastoma

OBJECTIVE

Herein we describe initial results in a porcine model of a fully implantable device designed to allow closed, repetitive photodynamic treatment of glioblastoma (GBM).

METHODS

This implant, Globus Lucidus, is a transparent quartz glass sphere with light-emitting diodes releasing wavelengths of 630 nm (19.5 mW/cm2), 405 nm (5.0 mW/cm2) or 275 nm (0.9 mW/cm2). 5-aminolevulinic acid was the photosensitizing prodrug chosen for use with Globus Lucidus, hence the implants illuminated at 630 nm or 405 nm. An additional 275 nm wavelength-emittance was included to explore the effects of photochemical therapy (PCT) by ultraviolet (UV) light. Twenty healthy domestic pigs underwent right-frontal craniotomies. The Globus Lucidus device was inserted into a surgically created right-frontal lobe cavity. After postoperative recovery, irradiation for up to 30 min daily for up to 14 d, or continuous irradiation for up to 14.6 h was conducted.

RESULTS

Surgery, implants, and repeated irradiations using the different wavelengths were generally well tolerated. Social behavior, wound healing, body weight, and temperature remained unaffected. Histopathological analyses revealed consistent leukocyte infiltration around the intracerebral implant sites with no significant differences between experimental and control groups.

CONCLUSION

This Globus Lucidus porcine study prepares the groundwork for adjuvant, long-term, repeated PDT of the GBM infiltration zone. This is the first report of a fully implantable PDT/PCT device for the potential treatment of GBM. A preclinical effectivity study of Globus Lucidus PDT/PCT is warranted and in advanced stages of planning.

Using mixed reality technique combines multimodal imaging signatures to adjuvant glioma photodynamic therapy

Background

Photodynamic therapy (PDT) promotes significant tumor regression and extends the lifetime of patients. The actual operation of PDT often relies on the subjective judgment of experienced neurosurgeons. Patients can benefit more from precisely targeting PDT's key operating zones.

Methods

We used magnetic resonance imaging scans and created 3D digital models of patient anatomy. Multiple images are aligned and merged in STL format. Neurosurgeons use HoloLens to import reconstructions and assist in PDT execution. Also, immunohistochemistry was used to explore the association of hyperperfusion sites in PDT of glioma with patient survival.

Results

We constructed satisfactory 3D visualization of glioma models and accurately localized the hyperperfused areas of the tumor. Tumor tissue taken in these areas was rich in CD31, VEGFA and EGFR that were associated with poor prognosis in glioma patients. We report the first study using MR technology combined with PDT in the treatment of glioma. Based on this model, neurosurgeons can focus PDT on the hyperperfused area of the glioma. A direct benefit was expected for the patients in this treatment.

Conclusion

Using the Mixed Reality technique combines multimodal imaging signatures to adjuvant glioma PDT can better exploit the vascular sealing effect of PDT on glioma.

Tumor-Associated Microglia/Macrophages as a Predictor for Survival in Glioblastoma and Temozolomide-Induced Changes in CXCR2 Signaling with New Resistance Overcoming Strategy by Combination Therapy

Tumor recurrence is the main challenge in glioblastoma (GBM) treatment. Gold standard therapy temozolomide (TMZ) is known to induce upregulation of IL8/CXCL2/CXCR2 signaling that promotes tumor progression and angiogenesis. Our aim was to verify the alterations on this signaling pathway in human GBM recurrence and to investigate the impact of TMZ in particular. Furthermore, a combi-therapy of TMZ and CXCR2 antagonization was established to assess the efficacy and tolerability. First, we analyzed 76 matched primary and recurrent GBM samples with regard to various histological aspects with a focus on the role of TMZ treatment and the assessment of predictors of overall survival (OS). Second, the combi-therapy with TMZ and CXCR2-antagonization was evaluated in a syngeneic mouse tumor model with in-depth immunohistological investigations and subsequent gene expression analyses. We observed a significantly decreased infiltration of tumor-associated microglia/macrophages (TAM) in recurrent tumors, while a high TAM infiltration in primary tumors was associated with a reduced OS. Additionally, more patients expressed IL8 in recurrent tumors and TMZ therapy maintained CXCL2 expression. In mice, enhanced anti-tumoral effects were observed after combi-therapy. In conclusion, high TAM infiltration predicts a survival disadvantage, supporting findings of the tumor-promoting phenotype of TAMs. Furthermore, the combination therapy seemed to be promising to overcome CXCR2-mediated resistance.

Multiscale Selectivity and in vivo Biodistribution of NRP-1-Targeted Theranostic AGuIX Nanoparticles for PDT of Glioblastoma

BACKGROUND

Local recurrences of glioblastoma (GBM) after heavy standard treatments remain frequent and lead to a poor prognostic. Major challenges are the infiltrative part of the tumor tissue which is the ultimate cause of recurrence. The therapeutic arsenal faces the difficulty of eradicating this infiltrating part of the tumor tissue while increasing the targeting of tumor and endogenous stromal cells such as angiogenic endothelial cells. In this aim, neuropilin-1 (NRP-1), a transmembrane receptor mainly overexpressed by endothelial cells of the tumor vascular system and associated with malignancy, proliferation and migration of GBM, highlighted to be a relevant molecular target to promote the anti-vascular effect of photodynamic therapy (VTP).

METHODS

The multiscale selectivity was investigated for KDKPPR peptide moiety targeting NRP-1 and a porphyrin molecule as photosensitizer (PS), both grafted onto original AGuIX design nanoparticle. AGuIX nanoparticle, currently in Phase II clinical trials for the treatment of brain metastases with radiotherapy, allows to achieve a real-time magnetic resonance imaging (MRI) and an accumulation in the tumor area by EPR (enhanced permeability and retention) effect. Using surface-plasmon resonance (SPR), we evaluated the affinities of KDKPPR and scramble free peptides, and also peptides-conjugated AGuIX nanoparticles to recombinant rat and human NRP-1 proteins. For in vivo selectivity, we used a cranial window model and parametric maps obtained from T2*-weighted perfusion MRI analysis.

RESULTS

The photophysical characteristics of the PS and KDKPPR molecular affinity for recombinant human NRP-1 proteins were maintained after the functionalization of AGuIX nanoparticle with a dissociation constant of 4.7 μM determined by SPR assays. Cranial window model and parametric maps, both revealed a prolonged retention in the vascular system of human xenotransplanted GBM. Thanks to the fluorescence of porphyrin by non-invasive imaging and the concentration of gadolinium evaluated after extraction of organs, we checked the absence of nanoparticle in the brains of tumor-free animals and highlighted elimination by renal excretion and hepatic metabolism.

CONCLUSION

Post-VTP follow-ups demonstrated promising tumor responses with a prolonged delay in tumor growth accompanied by a decrease in tumor metabolism.

Vascular targeted photodynamic therapy: A review of the efforts towards molecular targeting of tumor vasculature

The therapeutic value of vascular targeted photodynamic therapy (VTP) for cancer has already been recognized in the clinic: TOOKAD® has been clinically approved in Europe and Israel for treatment of men with low-risk prostate cancer. When light is applied shortly after intravenous administration of the photosensitizer, the damage is primarily done to the vasculature. This results in vessel constriction, blood flow stasis, and thrombus formation. Subsequently, the tumor is killed due to oxygen and nutrient deprivation. To further increase treatment specificity and to reduce undesired side effects such as damaging to the surrounding healthy tissues, efforts have been made to selectively target the PS to the tumor vasculature, an approach named molecular targeted VTP (molVTP). Several receptors have already been explored for this approach, namely CD13, CD276, Extra domains of fibronectin (A, B), Integrin αvβ3, Neuropilin-1, Nucleolin, PDGFRβ, tissue factor, and VEGFR-2, which are overexpressed on tumor vasculature. Preclinical studies have shown promising results, further encouraging the investigation and future application of molVTP, to improve selectivity and efficacy of cancer treatment. This strategy will hopefully lead to even more selective treatments for many cancer patients.

Impact of methylenetetrahydrofolate reductase C677T polymorphism on the efficacy of photodynamic therapy in patients with neovascular age-related macular degeneration

The most severe visual impairments due to age-related macular degeneration (AMD) are frequently caused by the occurrence of choroidal neovascularization (CNV). Although photodynamic therapy with verteporfin (PDT-V) is currently a second-line treatment for neovascular AMD, it can be conveniently combined with drugs acting against vascular endothelial growth factor (anti-VEGF) to reduce the healthcare burden associated with the growing necessity of anti-VEGF intravitreal re-injection. Because the common 677 C > T polymorphism of the methylenetetrahydrofolate reductase gene (MTHFR-C677T; rs1801133) has been described as predictor of satisfactory short-term responsiveness of AMD-related CNV to PDT-V, we retrospectively examined the outcomes of 371 Caucasian patients treated with standardized, pro-re-nata, photodynamic regimen for 24 months. Responder (R) and non-responder (NR) patients were distinguished on the basis of the total number of scheduled PDT-V (TN-PDT-V) and change of best-corrected visual acuity (∆-BCVA). The risk for both TN-PDT-V and ∆-BCVA to pass from R to NR group was strongly correlated with CT and TT genotypes of MTHFR-C677T variant resulting, respectively, in odd ratios of 0.19 [95% CI, 0.12-0.32] and 0.09 [95% CI, 0.04-0.21] (P < 0.001), and odd ratios of 0.24 [95% CI, 0.15-0.39] and 0.03 [95% CI, 0.01-0.11] (P < 0.001). These pharmacogenetic findings indicate a rational basis to optimize the future clinical application of PDT-V during the combined treatments of AMD-related CNV, highlighting the role of thrombophilia to be aware of the efficacy profile of photodynamic therapy.

Targeting the extradomain A of fibronectin allows identification of vascular resistance to antiangiogenic therapy in experimental glioma

Introduction

Clinical application of antiangiogenic therapy lacks direct visualization of therapy efficacy and vascular resistance. We aimed to establish molecular imaging during treatment with sunitinib using the fibronectin extradomain A specific small immunoprotein(SIP)-F8 in glioma.

Methods

Biodistribution analysis of F8-SIP-Alexa-555 was performed in SF126-glioma bearing or control mice (n = 23 and 7, respectively). Intravital microscopy(IVM) was performed on a microvascular level after 7 days (n = 5 per group) and subsequently after 6 days of sunitinib treatment (n = 4) or without (n = 2).

Additionally, near infrared fluorescence(NIRF) imaging was established with F8-SIP-Alexa-750 allowing non-invasive imaging with and without antiangiogenic treatment in orthotopic tumors (n = 38 divided in 4 groups). MRI was used to determine tumor size and served as a reference for NIRF imaging.

Results

F8-SIP demonstrated a time and hemodynamic dependent tumor specific accumulation. A significantly higher vascular accumulation occurred with antiangiogenic treatment compared to untreated tumors enabling visualization of resistant tumor vessels by F8-SIP-mediated NIRF imaging. In orthotopic tumors, sunitinib reduced F8-SIP-Alexa-750 enrichment volume but not fluorescence intensity indicative of F8-SIP accumulation in fewer vessels.

Conclusion

F8-SIP is highly tumor specific with time and hemodynamic dependent biodistribution. The higher vascular accumulation to remaining vessels enables molecular imaging and targeting of therapy resistant tumor vessels.

Porphyrin-based cationic amphiphilic photosensitisers as potential anticancer, antimicrobial and immunosuppressive agents

Photodynamic therapy (PDT) combines a photosensitiser, light and molecular oxygen to induce oxidative stress that can be used to kill pathogens, cancer cells and other highly proliferative cells. There is a growing number of clinically approved photosensitisers and applications of PDT, whose main advantages include the possibility of selective targeting, localised action and stimulation of the immune responses. Further improvements and broader use of PDT could be accomplished by designing new photosensitisers with increased selectivity and bioavailability. Porphyrin-based photosensitisers with amphiphilic properties, bearing one or more positive charges, are an effective tool in PDT against cancers, microbial infections and, most recently, autoimmune skin disorders. The aim of the review is to present some of the recent examples of the applications and research that employ this specific group of photosensitisers. Furthermore, we will highlight the link between their structural characteristics and PDT efficiency, which will be helpful as guidelines for rational design and evaluation of new PSs.