Novel Core–Shell Polyamine Phosphate Nanoparticles Self-Assembled from PEGylated Poly(allylamine hydrochloride) with Low Toxicity and Increased In Vivo Circulation Time

An approach for reducing toxicity and enhancing therapeutic potential of supramolecular polyamine phosphate nanoparticles (PANs) through PEGylation of polyamines before their assembly into nanoparticles is presented here. It is shown that the number of polyethylene glycol (PEG) chains for polyamine largely influence physico-chemical properties of PANs and their biological endpoints. Poly(allylamine hydrochloride) (PAH) are functionalized through carbodiimide chemistry with three ratios of PEG molecules per PAH chain: 0.1, 1, and 10. PEGylated PAH is then assembled into PANs by exposing the polymer to phosphate buffer solution. PANs decrease size and surface charge with increasing PEG ratios as evidenced by dynamic light scattering and zeta potential measurements, with the ten PEG/PAH ratio PANs having practically zero charge. Small angle X-ray scattering (SAXS) proves that PEG chains form a shell around a polyamine core, which is responsible for the screening of positive charges. MTT experiments show that the screening of amine groups decreases nanoparticle toxicity, with the lowest toxicity for the 10 PEG/PAH ratio. Fluorescence correlation spectroscopy (FCS) proves less interaction with proteins for PEGylated PANs. Positron emission tomography (PET) imaging of 18F labelled PANs shows longer circulation time in healthy mice for PEGylated PANs than non-PEGylated ones.Fil: Andreozzi, Patrizia. Basque Research and Technology Alliance; España. Università degli Studi di Firenze; ItaliaFil: Simó, Cristina. Basque Research and Technology Alliance; EspañaFil: Moretti, Paolo. Università Politecnica delle Marche; ItaliaFil: Martinez Porcel, Joaquin. Basque Research and Technology Alliance; EspañaFil: Lüdtke, Tanja Ursula. Basque Research and Technology Alliance; EspañaFil: Ramirez, Maria de Los Angeles. Basque Research and Technology Alliance; España. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tamberi, Lorenza. Basque Research and Technology Alliance; EspañaFil: Marradi, Marco. Università degli Studi di Firenze; ItaliaFil: Amenitsch, Heinz. Graz University Of Technology.; AustriaFil: Llop, Jordi. Basque Research and Technology Alliance; España. Centro de Investigación Biomédica En Red de Enfermedades Respiratorias; EspañaFil: Ortore, Maria Grazia. Università Politecnica Delle Marche; ItaliaFil: Moya, Sergio Enrique. Basque Research and Technology Alliance; Españ

The specific role of LEC neurons during episodic-like-memory formation and retrieval in the mouse

The Entorhinal Cortex (EC) represents a crucial site for memory formation as it integrates spatial information processed from its medial subdivision (MEC) with non-spatial information processed from its lateral part (LEC). Specific behavioural tests, such as the novel object-place-context recognition test (OPCRT) have been designed to investigate episodic-like memory in mice. Using this task, it has been demonstrated that LEC superficial layer neurons are required for recognition of objects that have been experienced in a specific context and that the specific lesion of the LEC causes an impairment in the ability to discriminate either novel object/place or novel object/place/context associations without affecting the recognition of a novel object. However, it is still not clear whether LEC superficial layer neurons are merely involved in object information processing during the formation or are re-activated during retrieval of associative memory. To address this issue, we planned to assess the specificity of LEC activation induced by the OPCRT. We first investigated OPCRT-induced synaptic changes in layer II LEC intrinsic circuitry compared to the adjacent MEC and the main target circuitry (performant pathway to dentate gyrus). Then we compared the neuronal activation in superficial and deep layers of the LEC compared to the MEC and other brain areas, using the c-fos as a marker of neuronal activity. Experiments were conducted on male C57bl/6J mice (3 to 4 months of age) that were divided in the following groups: mice subjected to OPCRT, mice exposed only to the contexts (CNTX) and mice remained in their home cages (CTRL). The test consists in the presentation of the objects in association with a specific position and context in the sample trials, followed by a test trial in which mice discriminate between familiar and novel OPC associations. Mice memory performance was quantified after the analysis of the time spent in the exploration of the two objects and expressed as discrimination index (DI = time at novel - time at familiar object / time at novel + time at familiar object). Electrophysiological analyses revealed the capability of OPCRT to induce significant changes in the synaptic efficacy in the LEC intrinsic circuitry, but not in the MEC nor in the hippocampus. The analysis of c-fos immunostaining revealed a significant and selective increase of EC activation after the execution of the task. In order to dissect the specific role of LEC neurons we made use of inducible- DREADDs (Designer Receptors Exclusively Activated by Designer Drugs) that were stereotaxically injected in the LEC to specifically manipulate transfected neurons during the OPCRT. In particular, inhibitory G protein-coupled receptor (GPCR) in LEC neurons could be expressed in a tamoxifen-dependent manner, and then activated by administration of CNO during the recall phase of the associative memory task. Selective inhibition of LEC neurons previously engaged during memory formation, resulted in a significant loss of associative memory. Our findings suggest that activation of a selective population of EC neurons is necessary not only for the formation but also for the retrieval of associative memory

Novel Core–Shell Polyamine Phosphate Nanoparticles Self‐Assembled from PEGylated Poly(allylamine hydrochloride) with Low Toxicity and Increased In Vivo Circulation Time (Small 35/2021)

An approach for reducing toxicity and enhancing therapeutic potential of supramolecular polyamine phosphate nanoparticles (PANs) through PEGylation of polyamines before their assembly into nanoparticles is presented here. It is shown that the number of polyethylene glycol (PEG) chains for polyamine largely influence physico-chemical properties of PANs and their biological endpoints. Poly(allylamine hydrochloride) (PAH) are functionalized through carbodiimide chemistry with three ratios of PEG molecules per PAH chain: 0.1, 1, and 10. PEGylated PAH is then assembled into PANs by exposing the polymer to phosphate buffer solution. PANs decrease size and surface charge with increasing PEG ratios as evidenced by dynamic light scattering and zeta potential measurements, with the ten PEG/PAH ratio PANs having practically zero charge. Small angle X-ray scattering (SAXS) proves that PEG chains form a shell around a polyamine core, which is responsible for the screening of positive charges. MTT experiments show that the screening of amine groups decreases nanoparticle toxicity, with the lowest toxicity for the 10 PEG/PAH ratio. Fluorescence correlation spectroscopy (FCS) proves less interaction with proteins for PEGylated PANs. Positron emission tomography (PET) imaging of F-18 labelled PANs shows longer circulation time in healthy mice for PEGylated PANs than non-PEGylated ones

Regret affects the choice between neoadjuvant therapy and upfront surgery for potentially resectable pancreatic cancer

Background: When treating potentially resectable pancreatic adenocarcinoma, therapeutic decisions are left to the sensibility of treating clinicians who, faced with a decision that post hoc can be proven wrong, may feel a sense of regret that they want to avoid. A regret-based decision model was applied to evaluate attitudes toward neoadjuvant therapy versus upfront surgery for potentially resectable pancreatic adenocarcinoma. Methods: Three clinical scenarios describing high-, intermediate-, and low-risk disease-specific mortality after upfront surgery were presented to 60 respondents (20 oncologists, 20 gastroenterologists, and 20 surgeons). Respondents were asked to report their regret of omission and commission regarding neoadjuvant chemotherapy on a scale between 0 (no regret) and 100 (maximum regret). The threshold model and a multilevel mixed regression were applied to analyze respondents' attitudes toward neoadjuvant therapy. Results: The lowest regret of omission was elicited in the low-risk scenario, and the highest regret in the high-risk scenario (P < .001). The regret of the commission was diametrically opposite to the regret of omission (P ≤ .001). The disease-specific threshold mortality at which upfront surgery is favored over the neoadjuvant therapy progressively decreased from the low-risk to the high-risk scenarios (P ≤ .001). The nonsurgeons working in or with lower surgical volume centers (P = .010) and surgeons (P = .018) accepted higher disease-specific mortality after upfront surgery, which resulted in the lower likelihood of adopting neoadjuvant therapy. Conclusion: Regret drives decision making in the management of pancreatic adenocarcinoma. Being a surgeon or a specialist working in surgical centers with lower patient volumes reduces the likelihood of recommending neoadjuvant therapy

Assessment of Ramucirumab plus paclitaxel as switch maintenance versus continuation of first-line chemotherapy in patients with advanced HER-2 negative gastric or gastroesophageal junction cancers: the ARMANI phase III trial

Abstract Background Platinum/fluoropyrimidine regimens are the backbone of first-line chemotherapy for advanced gastric cancer (AGC). However response rates to first line chemotherapy range from 30 to 50% and disease progression occurs after 4–6 cycles. The optimal duration of first-line therapy is still unknown and its continuation until disease progression represents the standard. However this strategy is often associated with cumulative toxicity and rapid development of drug resistance. Moreover, only about 40% of AGC pts. are eligible for second-line treatment. Methods This is a randomized, open-label, multicenter phase III trial. It aims at assessing whether switch maintenance to ramucirumab plus paclitaxel will extend the progression-free survival (PFS) of subjects with HER-2 negative AGC who have not progressed after 3 months of a first-line with a platinum/fluoropyrimidine regimen (either FOLFOX4, mFOLFOX6 or XELOX). The primary endpoint is to compare Progression-Free Survival (PFS) of patients in ARM A (switch maintenance to ramucirumab and placlitaxel) versus ARM B (continuation of the same first-line therapy with oxaliplatin/fluoropyrimidine). Secondary endpoints are: overall survival, time-to-treatment failure, overall response rate, duration of response, percentage of patients that will receive a second line therapy according to arm treatment, safety, quality of life. Exploratory studies including Next-Generation Sequencing (NGS) in archival tumor tissues are planned in order to identify potential biomarkers of primary resistance and prognosis. Discussion The ARMANI study estimates if patients treated with early swich with ramucirumab plus paclitaxel received benefit when compared to those treated with continuation of first line therapy. The hypothesis is that the early administration of an active, non-cross resistant second-line regimen such as ramucirumab plus paclitaxel may prolong the time in which patients are progression-free, and consequently have a better quality of life. Moreover, this strategy may rescue all those subjects that become ineligible for second-line therapy due to the rapid deterioration of health status after the first disease progression. Trial registration ARMANI is registered at ClinicalTrials.gov (NCT02934464, October 17, 2016) and EudraCT(2016–001783-12, April 202,016)