Taxane-Grafted Metal-Oxide Nanoparticles as a New Theranostic Tool against Cancer: The Promising Example of Docetaxel-Functionalized Titanate Nanotubes on Prostate Tumors

International audienceThe combination of anticancer drugs and metal oxide nanoparticles is of great interest in cancer nanomedicine. Here, the development of a new nanohybrid, titanate nanotube-docetaxel (TiONts-DTX) is reported, the two parts of which are conjugated by covalent linkages. Unlike most nanoparticles currently being developed for biomedical purposes, TiONts present a needle-shaped morphology. The surface of TiONts is linked with 3-aminopropyl triethoxysilane and with a hetero-bifunctional polymer (polyethylene glycol) to create well-dispersed and biocompatible nanovectors. The prefunctionalized surface of this scaffold has valuable attachments to graft therapeutic agents (DTX in our case) as well as chelating agents (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) to monitor the nanohybrids. To evaluate drug efficacy, in vitro tests have demonstrated that the association between TiONts and DTX shows cytotoxic activity against a hormone-refractory prostate cancer cell line (22Rv1) whereas TiONts without DTX do not. Finally, the first in vivo tests with intratumoral injections show that more than 70% of TiONts nanovectors are retained within the tumor for at least 7 d. Moreover, tumor growth in mice receiving TiONts-DTX is significantly slower than that in mice receiving free DTX. This nanohybrid can thus become a promising new tool in biomedicine to fight against prostate cancer

About the Influence of PEG Spacers on the Cytotoxicity of Titanate Nanotubes-Docetaxel Nanohybrids against a Prostate Cancer Cell Line

International audienceThe association between chemotherapeutic drugs and metal oxide nanoparticles has sparked a rapidly growing interest in cancer nanomedicine. The elaboration of new engineered docetaxel (DTX)-nanocarriers based on titanate nanotubes (TiONts) was reported. The idea was to maintain the drug inside cancer cells and avoid multidrug resistance mechanisms, which often limit drug efficacy by decreasing their intracellular concentrations in tumor cells. HS-PEGn-COOH (PEG: polyethylene glycol, n = 3000, 5000, 10,000) was conjugated, in an organic medium by covalent linkages, on TiONts surface. This study aimed to investigate the influence of different PEG derivatives chain lengths on the TiONts colloidal stability, on the PEGn density and conformation, as well as on the DTX biological activity in a prostate cancer model (human PC-3 prostate adenocarcinoma cells). In vitro tests highlighted significant cytotoxicities of the drug after loading DTX on PEGn-modified TiONts (TiONts-PEGn-DTX). Higher grafting densities for shorter PEGylated chains were most favorable on DTX cytotoxicity by promoting both colloidal stability in biological media and cells internalization. This promising strategy involves a better understanding of nanohybrid engineering, particularly on the PEGylated chain length influence, and can thus become a potent tool in nanomedicine to fight against cancer

The 6th R of Radiobiology: Reactivation of Anti-Tumor Immune Response

Historically, the 4Rs and then the 5Rs of radiobiology explained the effect of radiation therapy (RT) fractionation on the treatment efficacy. These 5Rs are: Repair, Redistribution, Reoxygenation, Repopulation and, more recently, intrinsic Radiosensitivity. Advances in radiobiology have demonstrated that RT is able to modify the tumor micro environment (TME) and to induce a local and systemic (abscopal effect) immune response. Conversely, RT is able to increase some immunosuppressive barriers, which can lead to tumor radioresistance. Fractionation and dose can affect the immunomodulatory properties of RT. Here, we review how fractionation, dose and timing shape the RT-induced anti-tumor immune response and the therapeutic effect of RT. We discuss how immunomodulators targeting immune checkpoint inhibitors and the cGAS/STING (cyclic GMP-AMP Synthase/Stimulator of Interferon Genes) pathway can be successfully combined with RT. We then review current trials evaluating the RT/Immunotherapy combination efficacy and suggest new innovative associations of RT with immunotherapies currently used in clinic or in development with strategic schedule administration (fractionation, dose, and timing) to reverse immune-related radioresistance. Overall, our work will present the existing evidence supporting the claim that the reactivation of the anti-tumor immune response can be regarded as the 6th R of Radiobiology

Correlation between radio-induced lymphocyte apoptosis measurements obtained from two French centres

International audiencePURPOSE OF THE RESEARCH:In the era of modern treatment delivery, increasing the dose delivered to the target to improve local control might be modulated by the patient's intrinsic radio-sensitivity. A predictive assay based on radio-induced lymphocyte apoptosis quantification highlighted the significant correlation between CD4 and CD8 T-lymphocyte apoptosis and grade 2 or 3 radiation-induced late toxicities. By conducting this assay at several technical platforms, the aim of this study was to demonstrate that radio-induced lymphocyte apoptosis values obtained from two different platforms were comparable.MATERIALS AND METHODS:For 25 patients included in the PARATOXOR trial running in Dijon the radio-induced lymphocyte apoptosis results obtained from the laboratory of Montpellier (IRCM, Inserm U1194, France), considered as the reference (referred to as Lab 1), were compared with those from the laboratory located at the Institut de cancérologie de Lorraine (ICL, France), referred to as Lab 2. Different statistical methods were used to measure the agreement between the radio-induced lymphocyte apoptosis data from the two laboratories (quantitative data). The Bland-Altman plot was used to identify potential bias.RESULTS:All statistical tests demonstrated good agreement between radio-induced lymphocyte apoptosis values obtained from both sites and no major bias was identified.CONCLUSIONS:Since radio-induced lymphocyte apoptosis values, which predict tolerance to radiotherapy, could be assessed by two laboratories and showed a high level of robustness and consistency, we can suggest that this assay be extended to any laboratories that use the same technique

Radiation could induce p53-independent and cell cycle - Unrelated apoptosis in 5-fluorouracil radiosensitized head and neck carcinoma cells

The effect of chemoresistance induction in radiosensitivity and cellular behavior after irradiation remains misunderstood. This study was designed to understand the relationship between radiation-induced cell cycle arrest, apoptosis, and radiosensitivity in KB cell line and KB3 subline selected after 5-fluorouracil (5FU) exposure. Exposure of KB cells to 5FU led to an increase in radiosensitivity. G 2/M cell cycle arrest was observed in the two cell lines after irradiation. The radioresistant KB cell line reached the maximum arrest two hours before KB3. The cellular exit from this arrest was found to be related to the wild type p53 protein expression induction. After irradiation, only KB3 cell line underwent apoptosis. This apoptosis induction seemed to be independent of G 2/M arrest exit, which was carried out later. The difference in radiosensitivity between KB and KB3 subline may result therefore from both a difference in apoptosis induction and a difference in G 2/M arrest maximum duration. Moreover, 5FU exposure has led to an increase in constitutive p53 protein expression, which may be associated with an increase in basal apoptosis cell fraction. Given the existing correlation between radiosensitivity and the percentage of basal apoptosis, the constitutive p53 protein expression may be related to intrinsic radiosensitivity in our cellular model.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Fast, reliable and cost-effective assay on lymphocytes to predict radiosensitivity: development on prostate and head and neck cohort

Abstract published in International Journal of Radiation Oncology, 102(3):e171, November 2018International audiencePurpose: The challenge of optimizing patient care around radiation therapy is constantly tackled with a flow of innovations (Robot assisted surgery, Protons, Spacer, etc.). Plethoras of studies demonstrated efficacy of new techniques and solutions, but still very few discriminate patients on their likelihood to encounter side effects. Radiosensitivity tests would be key in decision making in different cases: radiation vs surgery, hypo vs normofractionnated, proton vs photontherapy, and implementation of spacers. Recent studies based on immunofluorescence experiments have stressed the role of the ATM protein in the response to radiation on skin fibroblasts, and the statistical performances of this molecular endpoint to predict individual radiosensitivity (Granzotto et al, 2016). Faster and simpler solutions based on ELISA assay on fibroblast (EF) have confirmed that pATM is a relevant biomarker (Pereira et al, IJROBP 2018).The purpose of this study was to develop a predictive assay on lymphocytes based on the quantification of the pATM proteins by ELISA method. Materials and methods. A retrospective study was performed in blind on 102 blood lymphocytes from 56 radioresistant (RR) and 46 radiosensitive (RS) patients of two cancer types, prostate and head and neck. First, all patients were divided into 2 groups, RR (CTCAE<2) and RS (CTCAE≥2). The global quantity of pATM molecules was assessed by ELISA method. Secondly a classification study was carried out to estimate the threshold value of the biomarker able to minimize the number of false positive cases (RS patients identified RR). A Support Vector Machine classification technique was used to predict the radio-sensitivity. Statistical analysis was developed on R and performed independently.Results: Following promising results obtained with IF (AUC = 0.97) and EF (AUC = 0.85), the experiments performed on lymphocytes showed that the quantities of pATM molecules in each sample were found in agreement with the CTCAE grades. Statistical results showed the following mean values concerning the classification performances for all patients: sensitivity=86 %, specificity=72 %, AUC=79%, NPV=84 % and PPV=74 %.Conclusion: This study, performed using a single blood sample, confirmed results obtained with previous other methods while proposing the base of a realistic, cost effective assay to be potentially proposed to every patient intending to be treated with RT

Anti-PD-1/Anti-PD-L1 Drugs and Radiation Therapy: Combinations and Optimization Strategies

Immune checkpoint inhibitors have been associated with long-term complete responses leading to improved overall survival in several cancer types. However, these novel immunotherapies are only effective in a small proportion of patients, and therapeutic resistance represents a major limitation in clinical practice. As with chemotherapy, there is substantial evidence that radiation therapy promotes anti-tumor immune responses that can enhance systemic responses to immune checkpoint inhibitors. In this review, we discuss the main preclinical and clinical evidence on strategies that can lead to an enhanced response to PD-1/PD-L1 blockade in combination with radiation therapy. We focused on central issues in optimizing radiation therapy, such as the optimal dose and fractionation for improving the therapeutic ratio, as well as the impact on immune and clinical responses of dose rate, target volume, lymph nodes irradiation, and type of radiation particle. We explored the addition of a third immunomodulatory agent to the combination such as other checkpoint inhibitors, chemotherapy, and treatment targeting the tumor microenvironment components. The strategies described in this review provide a lead for future clinical trials

Constitutive NF-κB activity influences basal apoptosis and radiosensitivity of head-and-neck carcinoma cell lines

Purpose: Nuclear factor-κB (NF-κB) has been implicated in anti-apoptotic gene transactivation, according to its transcriptional activity. The present study was designed to investigate whether constitutive NF-κB activity could modulate basal apoptosis and intrinsic radiosensitivity of KB head-and-neck carcinoma cell line and KB3 subline. The KB3 subline was more radiosensitive (SF2 = 0.48, α = 0.064) than the radioresistant KB parental cell line (SF2 = 0.80, α = 0.114). Methods and Materials: Constitutive NF-κB DNA-binding activity was determined using electrophoretic mobility shift assay. Modulation of NF-κB activity was performed by exposing both cell lines to tumor necrosis factor α or dexamethasone. Apoptotic cell population was analyzed using flow cytometry (annexin V/propidium iodide). Radiosensitivity was assessed from determination of the surviving fraction at 2 Gy (SF2), and α and β parameters were determined using the linear-quadratic model. Results: Constitutive NF-κB activity was found to be significantly lower in KB3 than in KB. KB cell line exposure to dexamethasone significantly decreased NF-κB DNA-binding activity and, consequently, enhanced baseline apoptosis and radiosensitivity (α values: 0.114 vs. 0.052). Conversely, exposure of KB3 cells to tumor necrosis factor α increased NF-κB DNA-binding activity and resulted in a significant decrease (50%) in rate of apoptosis and in radiosensitivity (SF2 values: 0.48 vs. 0.63). Conclusions: Modulation of NF-κB DNA-binding activity influences baseline apoptosis and intrinsic radiosensitivity. © 2001 Elsevier Science Inc.SCOPUS: ar.jinfo:eu-repo/semantics/publishe