Phase II study of concomitant radiotherapy with atezolizumab in oligometastatic soft tissue sarcomas: STEREOSARC trial protocol.

INTRODUCTION: Up to 50% of soft tissue sarcoma (STS) patients develop metastases in the course of their disease. Cytotoxic therapy is a standard treatment in this setting but yields average tumour response rates of 25% at first line and ≤10% at later lines. In oligometastatic stage, stereotactic body radiation therapy (SBRT) allows reaching high control rates at treated sites (≥80%) and is potentially equally effective to surgery in term of overall survival. In order to shift the balance towards antitumour immunity by multisite irradiation, radiation could be combined with inhibitors of the immunosuppressive pathways. METHODS AND ANALYSIS: STEREOSARC is a prospective, multicentric, randomised phase II, designed to evaluate the efficacy of SBRT associated with immunotherapy versus SBRT only. Randomisation is performed with a 2:1 ratio within two arms. The primary objective is to evaluate the efficacy, in term of progression-free survival (PFS) rate at 6 months, of immunomodulated stereotactic multisite irradiation in oligometastatic sarcoma patients. The secondary objectives include PFS by immune response criteria, overall survival, quality-of-life evaluation and developing mathematical models of tumour growth and dissemination predictive of oligometastatic versus polymetastatic evolution. Patients will be randomised in two groups: SBRT with atezolizumab and SBRT alone. The total number of included patients should be 103. TRIAL REGISTRATION: The trial is registered on ClinicalTrials.gov (ID: NCT03548428). ETHICS AND DISSEMINATION: This study has been approved by Comité de Protection des Personnes du sud-ouest et outre-mer 4 on 18 October 2019 (Reference CPP2019-09-076-PP) and from National Agency for Medical and Health products Safety (Reference: MEDAECNAT-2019-08-00004_2017-004239-35) on 18 September 2019.The results will be disseminated to patients upon individual request or through media release from scientific meetings. The results will be communicated through scientific meetings and publications.

Unconventional binding sites and receptors for VIP and related peptides PACAP and PHI/PHM: an update.

The 28-amino-acid neuropeptide VIP and related peptides PACAP and PHI/PHM modulate virtually all of the vital functions in the body. These peptides are also commonly recognized as major regulators of cell growth and differentiation. Through their trophic and cytoprotective functions, they appear to play major roles in embryonic development, neurogenesis and the progression of a number of cancer types. These peptides bind to three well-characterized subtypes of G-protein coupled receptors: VPAC1 and VPAC2 share a common high affinity in the nanomolar range for VIP and PACAP; a third receptor type, PAC1, has been characterized for its high affinity for PACAP but its low affinity for VIP. Complex effects and pharmacological behaviors of these peptides suggest that multiple subtypes of binding sites may cooperate to mediate their function in target cells and tissues. In this complex response, some of these binding sites correspond to the definition of the conventional receptors cited above, while others display unexpected pharmacological and functional properties. Here we present potential clues that may lead investigators to further characterize the molecular nature and functions of these atypical binding species.

Expression and GTP sensitivity of peptide histidine isoleucine high-affinity-binding sites in rat.

High-affinity-binding sites for the vasoactive intestinal peptide (VIP) analogs peptide histidine/isoleucine-amide (PHI)/carboxyterminal methionine instead of isoleucine (PHM) are expressed in numerous tissues in the body but the nature of their receptors remains to be elucidated. The data presented indicate that PHI discriminated a high-affinity guanosine 5'-triphosphate (GTP)-insensitive-binding subtype that represented the totality of the PHI-binding sites in newborn rat tissues but was differentially expressed in adult animals. The GTP-insensitive PHI/PHM-binding sites were also observed in CHO cells over expressing the VPAC2 but not the VPAC1 VIP receptor.

Crucial role of neuron-enriched endosomal protein of 21 kDa in sorting between degradation and recycling of internalized G-protein-coupled receptors.

Recycling of endocytosed G-protein-coupled receptors involves a series of molecular events through early and recycling endosomes. The purpose of this work was to study the role of neuron-enriched endosomal protein of 21 kDa (NEEP21) in the recycling process of neurotensin receptors-1 and -2. Here we showed that suppression of NEEP21 expression does not modify the internalization rate of both receptors but strongly inhibited the recycling of the neurotensin receptor-2. In contrast, overexpression of NEEP21 changes the behavior of the neurotensin receptor-1 from a non-recycling to a recycling state. Recycling of the neurotensin receptor-2 involves both the phosphatidylinositol 3-kinase and the recycling endosome pathways, whereas recycling of the neurotensin receptor-1 induced by overexpression of NEEP21 only occurs by the phosphatidylinositol 3-kinase-dependent pathway. Taken together, these results confirm the essential role of NEEP21 in the recycling mechanism and show that this protein acts at the level of early endosomes to promote sorting of receptors toward a recycling pathway.