Molecular screening program to select molecular-based recommended therapies for metastatic cancer patients: analysis from the ProfiLER trial.

BACKGROUND: Antitumor activity of molecular-targeted agents is guided by the presence of documented genomic alteration in specific histological subtypes. We aim to explore the feasibility, efficacy and therapeutic impact of molecular profiling in routine setting. PATIENTS AND METHODS: This multicentric prospective study enrolled adult or pediatric patients with solid or hematological advanced cancer previously treated in advanced/metastatic setting and noneligible to curative treatment. Each molecular profile was established on tumor, relapse or biopsies, and reviewed by a molecular tumor board (MTB) to identify molecular-based recommended therapies (MBRT). The main outcome was to assess the incidence rate of genomic mutations in routine setting, across specific histological types. Secondary objectives included a description of patients with actionable alterations and for whom MBRT was initiated, and overall response rate. RESULTS: Four centers included 2579 patients from February 2013 to February 2017, and the MTB reviewed the molecular profiles achieved for 1980 (76.8%) patients. The most frequently altered genes were CDKN2A (N = 181, 7%), KRAS (N = 177, 7%), PIK3CA (N = 185, 7%), and CCND1 (N = 104, 4%). An MBRT was recommended for 699/2579 patients (27%), and only 163/2579 patients (6%) received at least one MBRT. Out of the 182 lines of MBRT initiated, 23 (13%) partial responses were observed. However, only 0.9% of the whole cohort experienced an objective response. CONCLUSION: An MBRT was provided for 27% of patients in our study, but only 6% of patients actually received matched therapy with an overall response rate of 0.9%. Molecular screening should not be used at present to guide decision-making in routine clinical practice outside of clinical trials.This trial is registered with ClinicalTrials.gov, number NCT01774409.

Genomic alterations and radioresistance in breast cancer: an analysis of the ProfiLER protocol.

BACKGROUND: Breast cancer (BC) patients with comparable prognostic features have heterogeneous outcomes, party related to a possible radiotherapy resistance leading to local-regional recurrences (LRR). The objective of the present study was to identify predictive molecular biomarkers of LRR of BC. PATIENTS AND METHODS: Genetic profile of 146 BC patients' tumours included in the ProfiLER clinical trial (NC01774409) between 2013 and 2016 were analysed using next-generation-sequencing and comparative-genomic-hybridization tests. Patients and tumour characteristics were retrospectively collected and analysed for association with genomic rearrangements (mutations, amplification, deletions). Only gene alterations observed in >3% of the tumours were selected. RESULTS: A total of 193 genomic rearrangements were identified, and 16 were observed in >3% of tumours. One was statistically correlated to the risk of local relapse. A median loco-regional progression-free survival (LRPFS) of 23.6 years was reported for PIK3CA mutation carriers (n = 31, 21.2%) versus 9.9 years for PIK3CA wild-type patients (HR 0.27, 95% CI 0.12-0.65, P = 0.002 in univariate analysis). PIK3CA mutation was identified as an independent protective factor on LRR using multivariate analysis (HR 0.29, 95% CI 0.09-0.99, P = 0.047). All other mutations, amplifications or deletions were not found associated with LRPFS. CONCLUSION: PIK3CA mutation was associated with a lower risk of local relapse in this population of BCs. This is consistent with recent studies suggesting PIK3CA to be part of biological pathways impacting the radiosensitivity.

Inhibition of cell death results in hyperganglionosis: implications for enteric nervous system development.

The enteric nervous system (ENS) is derived from vagal and sacral neural crest cells (NCC) that delaminate from the neural tube and undergo extensive migration and proliferation in order to colonize the entire length of the gut and differentiate into many millions of neurons and glial cells. Although apoptotic programmed cell death is an essential physiological process during development of the majority of the vertebrate nervous system, apoptosis within early ENS development has not been comprehensively investigated. The aim of this study was to determine the presence and extent of apoptosis within the vagal NCC population that gives rise to most of the ENS in the chick embryo. We demonstrated that apoptotic cells, as shown by terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling and active caspase-3 immunoreactivity, are present within an electroporated green fluorescent protein (GFP) and human natural killer-1 (HNK-1) immunopositive NCC population migrating from the vagal region of the neural tube to the developing foregut. Inhibition of caspase activity in vagal NCC, by electroporation with a dominant-negative form of caspase-9, increased the number of vagal NCC available for ENS formation, as shown by 3-dimensional reconstruction of serial GFP or HNK-1 labelled sections, and resulted in hyperganglionosis within the proximal foregut, as shown by NADPH-diaphorase whole gut staining. These findings suggest that apoptotic cell death may be a normal process within the precursor pool of pre-enteric NCC that migrates to the gut, and as such it may play a role in the control of ENS formation.

Netrin-1 interacts with amyloid precursor protein and regulates amyloid-beta production.

The beta-amyloid precursor protein (APP) is an orphan transmembrane receptor whose physiological role is largely unknown. APP is cleaved by proteases generating amyloid-beta (Abeta) peptide, the main component of the amyloid plaques that are associated with Alzheimer's disease. Here, we show that APP binds netrin-1, a multifunctional guidance and trophic factor. Netrin-1 binding modulates APP signaling triggering APP intracellular domain (AICD)-dependent gene transcription. Furthermore, netrin-1 binding suppresses Abeta peptide production in brain slices from Alzheimer model transgenic mice. In this mouse model, decreased netrin-1 expression is associated with increased Abeta concentration, thus supporting netrin-1 as a key regulator of Abeta production. Finally, we show that netrin-1 brain administration in Alzheimer model transgenic mice may be associated with an amelioration of the Alzheimer's phenotype.

The dependence receptor DCC (deleted in colorectal cancer) defines an alternative mechanism for caspase activation.

The expression of DCC (deleted in colorectal cancer) is often markedly reduced in colorectal and other cancers. However, the rarity of point mutations identified in DCC coding sequences and the lack of a tumor predisposition phenotype in DCC hemizygous mice have raised questions about its role as a tumor suppressor. DCC also mediates axon guidance and functions as a dependence receptor; such receptors create cellular states of dependence on their respective ligands by inducing apoptosis when unoccupied by ligand. We now show that DCC drives cell death independently of both the mitochondria-dependent pathway and the death receptor/caspase-8 pathway. Moreover, we demonstrate that DCC interacts with both caspase-3 and caspase-9 and drives the activation of caspase-3 through caspase-9 without a requirement for cytochrome c or Apaf-1. Hence, DCC defines an additional pathway for the apoptosome-independent caspase activation.

Netrin-1-mediated axon outgrowth and cAMP production requires interaction with adenosine A2b receptor.

The netrins, a family of laminin-related secreted proteins, are critical in controlling axon elongation and pathfinding. The DCC (for deleted in colorectal cancer) protein was proposed as a receptor for netrin-1 in the light of many observations including the inhibition of netrin-1-mediated axon outgrowth and attraction in the presence of an anti-DCC antiserum, the similitude of nervous system defects in DCC and netrin-1 knockout mice and the results of receptor swapping experiments. Previous studies have failed to show a direct interaction of DCC with netrin-1 (ref. 10), suggesting the possibility of an additional receptor or co-receptor. Here we show that DCC interacts with the membrane-associated adenosine A2b receptor, a G-protein-coupled receptor that induces cAMP accumulation on binding adenosine. We show that A2b is actually a netrin-1 receptor and induces cAMP accumulation on binding netrin-1. Finally, we show that netrin-1-dependent outgrowth of dorsal spinal cord axons directly involves A2b. Together our results indicate that the growth-promoting function of netrin-1 may require a receptor complex containing DCC and A2b.

The RET proto-oncogene induces apoptosis: a novel mechanism for Hirschsprung disease.

The RET (rearranged during transfection) proto-oncogene encodes a tyrosine kinase receptor involved in both multiple endocrine neoplasia type 2 (MEN 2), an inherited cancer syndrome, and Hirschsprung disease (HSCR), a developmental defect of enteric neurons. We report here that the expression of RET receptor induces apoptosis. This pro-apoptotic effect of RET is inhibited in the presence of its ligand glial cell line-derived neurotrophic factor (GDNF). Furthermore, we present evidence that RET induces apoptosis via its own cleavage by caspases, a phenomenon allowing the liberation/exposure of a pro-apoptotic domain of RET. In addition, we report that Hirschsprung-associated RET mutations impair GDNF control of RET pro-apoptotic activity. These results indicate that HSCR may result from apoptosis of RET-expressing enteric neuroblasts.