NEPTUNE (Nuclear process-driven Enhancement of Proton Therapy UNravEled)

Protontherapy is an important radiation modality that has been used to treat cancer for over 60 years. In the last 10 years, clinical proton therapy has been rapidly growing with more than 80 facilities worldwide [1]. The interest in proton therapy stems from the physical properties of protons allowing for a much improved dose shaping around the target and greater healthy tissue sparing. One shortcoming of protontherapy is its inability to treat radioresistant cancers, being protons radiobiologically almost as effective as photons. Heavier particles, such as 12C ions, can overcome radioresistance but they present radiobiological and economic issues that hamper their widespread adoption. Therefore, many strategies have been designed to increase the biological effectiveness of proton beams. Examples are chemical radiosensitizing agents or, more recently, metallic nanoparticles. The goal of this project is to investigate the use of nuclear reactions triggered by protons generating short-range high- LET alpha particles inside the tumours, thereby allowing a highly localized DNA-damaging action. Specifically, we intend to consolidate and explain the promising results recently published in [2], where a significant enhancement of biological effectiveness was achieved by the p-11B reaction. Clinically relevant binary approaches were first proposed with Boron Neutron Capture Therapy (BNCT), which exploits thermal neutron capture in 10B, suitably accumulated into tumour before irradiation. The radiosensitising effects due to the presence of 10B will be compared to those elicited by p-11B, using the same carrier and relating the observed effects with intracellular 11B and 10B distribution as well as modelled particle action and measured dose deposition at the micro/nanometer scale. Moreover, the p-19F reaction, which also generates secondary particles potentially leading to local enhancement of proton effectiveness, will be investigated. The in-vivo imaging of 11B and 19F carriers will be studied, in particular by optimizing 19F-based magnetic resonance

Inhibition of Wnt/β-Catenin pathway and Histone acetyltransferase activity by Rimonabant: a therapeutic target for colon cancer

In a high percentage (≥85%) of both sporadic and familial adenomatous polyposis forms of colorectal cancer (CRC), the inactivation of the APC tumor suppressor gene initiates tumor formation and modulates the Wnt/β-Catenin transduction pathways involved in the control of cell proliferation, adhesion and metastasis. Increasing evidence showed that the endocannabinoids control tumor growth and progression, both in vitro and in vivo. We evaluated the effect of Rimonabant, a Cannabinoid Receptor 1 (CB1) inverse agonist, on the Wnt/β-Catenin pathway in HCT116 and SW48 cell lines carrying the genetic profile of metastatic CRC poorly responsive to chemotherapies. In these models, Rimonabant inhibited the Wnt/β-Catenin canonical pathway and increased β-Catenin phosphorylation; in HCT116 cells, but not in SW48, the compound also triggered the Wnt/β-Catenin non canonical pathway activation through induction of Wnt5A and activation of CaMKII. The Rimonabant-induced downregulation of Wnt/β-Catenin target genes was partially ascribable to a direct inhibition of p300/KAT3B histone acetyltransferase, a coactivator of β-Catenin dependent gene regulation. Finally, in HCT116 xenografts, Rimonabant significantly reduced tumor growth and destabilized the nuclear localization of β-Catenin. Obtained data heavily supported the rationale for the use of cannabinoids in combined therapies for metastatic CRC harbouring activating mutations of β-Catenin

Stereotactic Radiation Therapy for Brain Metastases: Factors Affecting Outcomes and Radiation Necrosis

Stereotactic radiation therapy (SRT) is a proven effective treatment for brain metastases (BM); however, symptomatic radiation necrosis (RN) is a late effect that may impact on patient’s quality of life. The aim of our study was to retrospectively evaluate survival outcomes and characterize the occurrence of RN in a cohort of BM patients treated with ablative SRT at Federico II University Hospital. Clinical and dosimetric factors of 87 patients bearing a total of 220 BMs treated with SRT from 2016 to 2022 were analyzed. Among them, 46 patients with 127 BMs having clinical and MRI follow-up (FUP) ≥ 6 months were selected for RN evaluation. Dosimetric parameters of the uninvolved brain (brain without GTV) were extracted. The crude local control was 91% with neither clinical factors nor prescription dose correlating with local failure (LF). At a median FUP of 9 (1–68) months, the estimated median overall survival (OS), progression-free survival (PFS), and brain progression-free survival (bPFS) were 16, 6, and 9 months, respectively. The estimated OS rates at 1 and 3 years were 59.8% and 18.3%, respectively; bPFS at 1 and 3 years was 29.9% and 13.5%, respectively; PFS at 1 and 3 years was 15.7% and 0%, respectively; and local failure-free survival (LFFS) at 1 and 3 years was 87.2% and 83.8%, respectively. Extracranial disease status was an independent factor related to OS. Fourteen (30%) patients manifested RN. At multivariate analysis, adenocarcinoma histology, left location, and absence of chemotherapy were confirmed as independent risk factors for any-grade RN. Nine (20%) patients developed symptomatic (G2) RN, which improved or stabilized after 1–16 months of steroid therapy. With prompt recognition and, when necessary, medical therapy, RN radiological and clinical amelioration can be obtained

Identification of a Protein Arginine Methyltransferase 7 (PRMT7)/Protein Arginine Methyltransferase 9 (PRMT9) Inhibitor

Less studied than the other protein arginine methyltransferaseisoforms, PRMT7 and PRMT9 have recently been identified as importanttherapeutic targets. Yet, most of their biological roles and functionsare still to be defined, as well as the structural requirements thatcould drive the identification of selective modulators of their activity.We recently described the structural requirements that led to theidentification of potent and selective PRMT4 inhibitors spanning boththe substrate and the cosubstrate pockets. The reanalysis of the datasuggested a PRMT7 preferential binding for shorter derivatives andprompted us to extend these structural studies to PRMT9. Here, wereport the identification of the first potent PRMT7/9 inhibitor andits binding mode to the two PRMT enzymes. Label-free quantificationmass spectrometry confirmed significant inhibition of PRMT activityin cells. We also report the setup of an effective AlphaLISA assayto screen small molecule inhibitors of PRMT9

The Proton-Boron Reaction Increases the Radiobiological Effectiveness of Clinical Low- and High-Energy Proton Beams: Novel Experimental Evidence and Perspectives

Protontherapy is a rapidly expanding radiotherapy modality where accelerated proton beams are used to precisely deliver the dose to the tumor target but is generally considered ineffective against radioresistant tumors. Proton-Boron Capture Therapy (PBCT) is a novel approach aimed at enhancing proton biological effectiveness. PBCT exploits a nuclear fusion reaction between low-energy protons and (11)B atoms, i.e. p+(11)B→ 3α (p-B), which is supposed to produce highly-DNA damaging α-particles exclusively across the tumor-conformed Spread-Out Bragg Peak (SOBP), without harming healthy tissues in the beam entrance channel. To confirm previous work on PBCT, here we report new in-vitro data obtained at the 62-MeV ocular melanoma-dedicated proton beamline of the INFN-Laboratori Nazionali del Sud (LNS), Catania, Italy. For the first time, we also tested PBCT at the 250-MeV proton beamline used for deep-seated cancers at the Centro Nazionale di Adroterapia Oncologica (CNAO), Pavia, Italy. We used Sodium Mercaptododecaborate (BSH) as (11)B carrier, DU145 prostate cancer cells to assess cell killing and non-cancer epithelial breast MCF-10A cells for quantifying chromosome aberrations (CAs) by FISH painting and DNA repair pathway protein expression by western blotting. Cells were exposed at various depths along the two clinical SOBPs. Compared to exposure in the absence of boron, proton irradiation in the presence of BSH significantly reduced DU145 clonogenic survival and increased both frequency and complexity of CAs in MCF-10A cells at the mid- and distal SOBP positions, but not at the beam entrance. BSH-mediated enhancement of DNA damage response was also found at mid-SOBP. These results corroborate PBCT as a strategy to render protontherapy amenable towards radiotherapy-resilient tumor. If coupled with emerging proton FLASH radiotherapy modalities, PBCT could thus widen the protontherapy therapeutic index