Intermolecular pi-Electron Perturbations Generate Extrinsic Visible Contributions to Eumelanin Black Chromophore in Model Polymers with Interrupted Interring Conjugation

The key structural factors underlying the unique black chromophore of eumelanin biopolymers have so far defied elucidation. Capitalizing on the ability of 1% polyvinylalcohol (PVA) to prevent pigment precipitation during melanogenesis in vitro, we have investigated the visible chromophore properties of soluble eumelanin-like polymers produced by biomimetic oxidation of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic (DHICA) in 1% PVA-containing buffer at pH 7. Upon dilution DHI-eumelanin solutions exhibited almost linear visible absorbance changes, whereas DHICA-eumelanin displayed a remarkable deviation from linearity in simple buffer, but not in PVA-containing buffer. It is suggested that in DHICA polymers, exhibiting repeated interruptions of interring conjugation due to lack of planar conformations, the black chromophore is not due to an overlap of static entities defined intrinsically by the conjugation length across the carbon frame, but results largely from aggregation-related intermolecular perturbations of the -electron systems which are extrinsic in character

Intermolecular pi-Electron Perturbations Generate Extrinsic Visible Contributions to Eumelanin Black Chromophore in Model Polymers with Interrupted Interring Conjugation

The key structural factors underlying the unique black chromophore of eumelanin biopolymers have so far defied elucidation. Capitalizing on the ability of 1% polyvinylalcohol (PVA) to prevent pigment precipitation during melanogenesis in vitro, we have investigated the visible chromophore properties of soluble eumelanin-like polymers produced by biomimetic oxidation of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic (DHICA) in 1% PVA-containing buffer at pH 7. Upon dilution DHI-eumelanin solutions exhibited almost linear visible absorbance changes, whereas DHICA-eumelanin displayed a remarkable deviation from linearity in simple buffer, but not in PVA-containing buffer. It is suggested that in DHICA polymers, exhibiting repeated interruptions of interring conjugation due to lack of planar conformations, the black chromophore is not due to an overlap of static entities defined intrinsically by the conjugation length across the carbon frame, but results largely from aggregation-related intermolecular perturbations of the -electron systems which are extrinsic in character

5,6-Dihydroxyindole oxidation in phosphate buffer/polyvinyl alcohol: a new model system for studies of visible chromophore development in synthetic eumelanin polymers.

The determinants of the broadband absorption spectrum of eumelanins are still largely unknown. Herein the authors report a novel approach to investigate eumelanin chromophore which is based on the biomimetic oxidn. of the key monomer precursor, 5,6-dihydroxyindole (DHI), with peroxidase/hydrogen peroxide in phosphate buffer, pH 7, contg. 1-5% polyvinylalc. (PVA, 27,000 Da). This approach relies on the discovery that as low as 1% PVA can prevent pptn. of the growing melanin polymer thus allowing investigation of the chromophoric phases accompanying oxidn. of DHI without confounding scattering effects. Spectrophotometric monitoring showed the initial development of a band around 530 nm persisting for about 1 h before gradually changing into the typical broadband spectrum of eumelanin. Reductive treatment caused a significant absorbance decrease in the visible region without affecting an absorption band around 320 nm. Initial product anal. indicated an altered formation ratio of 2,4'-biindolyl (2) and 2,7'-biindolyl (3) relative to control expts. Overall, these results demonstrate for the first time that the development in soln. of visible chromophores since the early oligomer stages is independent of strong aggregation/pptn. phenomena

5,6-Dihydroxyindole oxidation in phosphate buffer/polyvinyl alcohol: a new model system for studies of visible chromophore development in synthetic eumelanin polymers

The determinants of the broadband absorption spectrum of eumelanins are still largely unknown. Herein the authors report a novel approach to investigate eumelanin chromophore which is based on the biomimetic oxidn. of the key monomer precursor, 5,6-dihydroxyindole (DHI), with peroxidase/hydrogen peroxide in phosphate buffer, pH 7, contg. 1-5% polyvinylalc. (PVA, 27,000 Da). This approach relies on the discovery that as low as 1% PVA can prevent pptn. of the growing melanin polymer thus allowing investigation of the chromophoric phases accompanying oxidn. of DHI without confounding scattering effects. Spectrophotometric monitoring showed the initial development of a band around 530 nm persisting for about 1 h before gradually changing into the typical broadband spectrum of eumelanin. Reductive treatment caused a significant absorbance decrease in the visible region without affecting an absorption band around 320 nm. Initial product anal. indicated an altered formation ratio of 2,4'-biindolyl (2) and 2,7'-biindolyl (3) relative to control expts. Overall, these results demonstrate for the first time that the development in soln. of visible chromophores since the early oligomer stages is independent of strong aggregation/pptn. phenomena

Treatment intensification with hepatic arterial infusion chemotherapy in patients with liver-only colorectal metastases still unresectable after systemic induction chemotherapy -a randomized phase II study --SULTAN UCGI 30/PRODIGE 53 (NCT03164655)-study protocol

International audienceBACKGROUND: Approximately 40% of colorectal cancer patients will develop colorectal liver metastases (CRLM). The most effective approach to increase long-term survival is CRLM complete resection. Unfortunately, only 10-15% of CRLM are initially considered resectable. The objective response rates (ORR) after current first-line systemic chemotherapy (sys-CT) regimens range from 40 to 80% and complete resection rates (CRR) range from 25 to 50% in patients with initially unresectable CRLM. When CRLM patients are not amenable to complete resection after induction of sys-CT, ORRs obtained with second-line sys-CT are much lower (between 10 and 30%) and consequently CRRs are also low (< 10%). Hepatic arterial infusion (HAI) oxaliplatin may represent a salvage therapy in patients with CRLM unresectable after one or more sys-CT regimens with ORRs and CRRs up to 60 and 30%, respectively. This study is designed to evaluate the efficacy of an intensification strategy based on HAI oxaliplatin combined with sys-CT as a salvage treatment in patients with CRLM unresectable after at least 2 months of first-line induction sys-CT.OBJECTIVES AND ENDPOINTS OF THE PHASE II STUDY: Our main objective is to investigate the efficacy, in term of CRR (R0-R1), of treatment intensification in patients with liver-only CRLM not amenable to curative-intent resection (and/or ablation) after at least 2 months of induction sys-CT. Patients will receive either HAI oxaliplatin plus systemic FOLFIRI plus targeted therapy (i.e. anti-EGFR antibody or bevacizumab) or conventional sys-CT plus targeted therapy (i.e. anti-EGFR or antiangiogenic antibody). Secondary objectives are to compare: progression-free survival, overall survival, objective response rate, depth of response, feasibility of delivering HAI oxaliplatin including HAI catheter-related complications, and toxicity (NCI-CTCAE v4.0).METHODS: This study is a multicenter, randomized, comparative phase II trial (power, 80%; two-sided alpha-risk, 5%). Patients will be randomly assigned in a 1:1 ratio to receive HAI oxaliplatin combined with systemic FOLFIRI plus targeted therapy (experimental arm) or the best sys-CT plus targeted therapy on the basis of their first-line prior sys-CT history and current guidelines (control arm). One hundred forty patients are required to account for non-evaluable patients

Association of Radiochemotherapy to Immunotherapy in unresectable locally advanced Oesophageal carciNoma—randomized phase 2 trial ARION UCGI 33/PRODIGE 67: the study protocol

Abstract Background In case of locally advanced and/or non-metastatic unresectable esophageal cancer, definitive chemoradiotherapy (CRT) delivering 50 Gy in 25 daily fractions in combination with platinum-based regimen remains the standard of care resulting in a 2-year disease-free survival of 25% which deserves to be associated with new systemic strategies. In recent years, several immune checkpoint inhibitors (anti-PD1/anti-PD-L1, anti-Program-Death 1/anti-Program-Death ligand 1) have been approved for the treatment of various solid malignancies including metastatic esophageal cancer. As such, we hypothesized that the addition of an anti-PD-L1 to CRT would provide clinical benefit for patients with locally advanced oesophageal cancer. To assess the efficacy of the anti-PD-L1 durvalumab in combination with CRT and then as maintenance therapy we designed the randomized phase II ARION (Association of Radiochemotherapy with Immunotherapy in unresectable Oesophageal carciNoma- UCGI 33/PRODIGE 67). Methods ARION is a multicenter, open-label, randomized, comparative phase II trial. Patients are randomly assigned in a 1:1 ratio in each arm with a stratification according to tumor stage, histology and centre. Experimental arm relies on CRT with 50 Gy in 25 daily fractions in combination with FOLFOX regimen administrated during and after radiotherapy every two weeks for a total of 6 cycles and durvalumab starting with CRT for a total of 12 infusions. Standard arm is CRT alone. Use of Intensity Modulated radiotherapy is mandatory. The primary endpoint is to increase progression-free survival at 12 months from 50 to 68% (HR = 0.55) (power 90%; one-sided alpha-risk, 10%). Progression will be defined with central external review of imaging. Ancillary studies are planned PD-L1 Combined Positivity Score on carcinoma cells and stromal immune cells of diagnostic biopsy specimen will be correlated to disease free survival. The study of gut microbiota will aim to determine if baseline intestinal bacteria correlates with tumor response. Proteomic analysis on blood samples will compare long-term responder after CRT with durvalumab to non-responder to identify biomarkers. Conclusion Results of the present study will be of great importance to evaluate the impact of immunotherapy in combination with CRT and decipher immune response in this unmet need clinical situation. Trial registration ClinicalTrials.gov, NCT: 03777813.Trial registration date: 5th December 2018

Association of COVID-19 Lockdown With the Tumor Burden in Patients With Newly Diagnosed Metastatic Colorectal Cancer

International audienceThe COVID-19 pandemic has been associated with substantial reduction in screening, case identification, and hospital referrals among patients with cancer. However, no study has quantitatively examined the implications of this correlation for cancer patient management.Objective: To evaluate the association of the COVID-19 pandemic lockdown with the tumor burden of patients who were diagnosed with metastatic colorectal cancer (mCRC) before vs after lockdown.Design, setting, and participants: This cohort study analyzed participants in the screening procedure of the PANIRINOX (Phase II Randomized Study Comparing FOLFIRINOX + Panitumumab vs FOLFOX + Panitumumab in Metastatic Colorectal Cancer Patients Stratified by RAS Status from Circulating DNA Analysis) phase 2 randomized clinical trial. These newly diagnosed patients received care at 1 of 18 different clinical centers in France and were recruited before or after the lockdown was enacted in France in the spring of 2020. Patients underwent a blood-sampling screening procedure to identify their RAS and BRAF tumor status.Exposures: mCRC.Main outcomes and measures: Circulating tumor DNA (ctDNA) analysis was used to identify RAS and BRAF status. Tumor burden was evaluated by the total plasma ctDNA concentration. The median ctDNA concentration was compared in patients who underwent screening before (November 11, 2019, to March 9, 2020) vs after (May 14 to September 3, 2020) lockdown and in patients who were included from the start of the PANIRINOX study.Results: A total of 80 patients were included, of whom 40 underwent screening before and 40 others underwent screening after the first COVID-19 lockdown in France. These patients included 48 men (60.0%) and 32 women (40.0%) and had a median (range) age of 62 (37-77) years. The median ctDNA concentration was statistically higher in patients who were newly diagnosed after lockdown compared with those who were diagnosed before lockdown (119.2 ng/mL vs 17.3 ng/mL; P < .001). Patients with mCRC and high ctDNA concentration had lower median survival compared with those with lower concentration (14.7 [95% CI, 8.8-18.0] months vs 20.0 [95% CI, 14.1-32.0] months). This finding points to the potential adverse consequences of the COVID-19 pandemic and related lockdown.Conclusions and relevance: This cohort study found that tumor burden differed between patients who received an mCRC diagnosis before vs after the first COVID-19 lockdown in France. The findings of this study suggest that CRC is a major area for intervention to minimize pandemic-associated delays in screening, diagnosis, and treatment

GD2-targeting CAR T-cell therapy for patients with GD2+ medulloblastoma

Purpose: Medulloblastoma (MB), the most common childhood malignant brain tumor, has a poor prognosis in about 30% of patients. The current standard of care, which includes surgery, radiation and chemotherapy, is often responsible for cognitive, neurologic and endocrine side effects. We investigated whether chimeric antigen receptor (CAR) T-cells directed towards the disialoganglioside GD2 can represent a potentially more effective treatment with reduced long-term side effects. Experimental design: GD2 expression was evaluated on primary tumor biopsies of MB children by flow-cytometry. GD2 expression in MB cells was evaluated also in response to an EZH2 inhibitor (Tazemetostat). In in vitro, as well as in in vivo models, GD2+MB cells were targeted by a CAR-GD2.CD28.4-1BBζ (CAR.GD2)-T construct, including the suicide gene inducible-caspase-9. Results: GD2 was expressed in 73.17% of MB tumors. The SHH and G4 subtypes expressed the highest levels of GD2, while the WNT subtype the lowest. In in-vitro co-culture assays, CAR.GD2 T-cells were able to kill GD2+MB cells. Pre-treatment with Tazemetostat upregulated GD2 expression, sensitizing GD2dimMB cells to CAR.GD2 T-cells cytotoxic activity. In orthotopic mouse models of MB, intravenously injected CAR.GD2 T-cells significantly controlled tumor growth, prolonging overall survival of treated mice. Moreover, the dimerizing drug AP1903 was able to cross the murine blood brain barrier and to eliminate both blood circulating and tumor infiltrating CAR.GD2 T-cells. Conclusions: Our experimental data indicate the feasibility of CAR.GD2 T-cell therapy. A phase I/II clinical trial will be conducted to evaluate the safety and therapeutic efficacy of CAR.GD2 therapy in high-risk MB patients