The LEGACy study: a European and Latin American consortium to identify risk factors and molecular phenotypes in gastric cancer to improve prevention strategies and personalized clinical decision making globally.

BACKGROUND: Gastric Cancer (GC) is the fourth most deadly cancer worldwide. Enhanced understanding of its key epidemiological and molecular drivers is urgently needed to lower the incidence and improve outcomes. Furthermore, tumor biology in European (EU) and Latin American (LATAM) countries is understudied. The LEGACy study is a Horizon 2020 funded multi-institutional research approach to 1) detail the epidemiological features including risk factors of GC in current time and 2) develop cost-effective methods to identify and integrate biological biomarkers needed to guide diagnostic and therapeutic approaches with the aim of filling the knowledge gap on GC in these areas. METHODS: This observational study has three parts that are conducted in parallel during 2019-2023 across recruiting centers from four EU and four LATAM countries: Part 1) A case-control study (800 cases and 800 controls) using questionnaires on candidate risk factors for GC, which will be correlated with clinical, demographic and epidemiological parameters. Part 2) A case-control tissue sampling study (400 cases and 400 controls) using proteome, genome, microbiome and immune analyses to characterize advanced (stage III and IV) GC. Patients in this part of the study will be followed over time to observe clinical outcomes. The first half of samples will be used as training cohort to identify the most relevant risk factors and biomarkers, which will be selected to propose cost-effective diagnostic and predictive methods that will be validated with the second half of samples. Part 3) An educational study, as part of our prevention strategy (subjects recruited from the general public) to test and disseminate knowledge on GC risk factors and symptoms by a questionnaire and informative video. Patients could be recruited for more than one of the three LEGACy studies. DISCUSSION: The LEGACy study aims to generate novel, in-depth knowledge on the tumor biological characteristics through integrating epidemiological, multi-omics and clinical data from GC patients at an EU-LATAM partnership. During the study, cost-effective panels with potential use in clinical decision making will be developed and validated. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: Part 1: NCT03957031 . Part 2: NCT04015466 . Part 3: NCT04019808 .

ESMO Scale for Clinical Actionability of Molecular Targets Driving Targeted Treatment in Patients with Cholangiocarcinoma.

PURPOSE: Treatment options for advanced cholangiocarcinoma are limited and prognosis is poor. Cholangiocarcinomas are highly heterogeneous at the molecular level, with divergent patterns between intrahepatic and extrahepatic forms, intrahepatic being particularly rich in actionable alterations. We compared survival in patients with advanced cholangiocarcinoma harboring alterations matched to targeted drugs, with patients harboring nonactionable alterations. EXPERIMENTAL DESIGN: Patients with cholangiocarcinoma treated between 2011 and 2020 at one institution, with available molecular analyses, were retrospectively reviewed. Genomic alteration actionability was classified according to the ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT) and correlated with efficacy endpoints. RESULTS: Of 327 patients included, 78.9% had intrahepatic cholangiocarcinoma, 97.9% had received chemotherapy for metastatic disease. Actionable molecular alterations per ESCAT were identified in 184 patients (56.3%), including IDH1 mutations and FGFR2 fusions (23.1% and 8.0% of patients with intrahepatic cholangiocarcinoma, respectively). Median overall survival in 50 patients with ESCAT I-IV alterations who received matched therapy (48 with intrahepatic cholangiocarcinoma) was 22.6 months [95% confidence interval (CI), 20.1-32.8], compared with 14.3 months (95% CI 11.9-18.1) in 130 patients without actionable ESCAT alterations (HR, 0.58; 95% CI, 0.40-0.85; P = 0.005). Among patients receiving matched targeted therapy, median progression-free survival was longer for patients with alterations classified as ESCAT I-II compared with ESCAT III-IV (5.0 vs. 1.9 months; HR, 0.36; 95% CI, 0.15-0.87; P = 0.02). CONCLUSIONS: ESCAT represents a tool to guide clinicians in fine-tuning use of molecular profiling data to choose matched targeted therapies. Our data demonstrate that targeted treatment administered per alteration actionability according to ESCAT is associated with improved survival in cholangiocarcinoma, particularly in ESCAT I-II intrahepatic cholangiocarcinoma.

Characterization of the atypical Ppz/Hal3 phosphatase system from the pathogenic fungus Cryptococcus neoformans.

Ppz Ser/Thr protein phosphatases (PPases) are found only in fungi and have been proposed as potential antifungal targets. In Saccharomyces cerevisiae Ppz1 (ScPpz1) is involved in regulation of monovalent cation homeostasis. ScPpz1 is inhibited by two regulatory proteins, Hal3 and Vhs3, which have moonlighting properties, contributing to the formation of an unusual heterotrimeric PPC decarboxylase (PPCDC) complex crucial for CoA biosynthesis. Here we report the functional characterization of CnPpz1 (CNAG_03673) and two possible Hal3-like proteins, CnHal3a (CNAG_00909) and CnHal3b (CNAG_07348) from the pathogenic fungus Cryptococcus neoformans. Deletion of CnPpz1 or CnHal3b led to phenotypes unrelated to those observed in the equivalent S. cerevisiae mutants, and the CnHal3b-deficient strain was less virulent. CnPpz1 is a functional PPase and partially replaced endogenous ScPpz1. Both CnHal3a and CnHal3b interact with ScPpz1 and CnPpz1 in vitro but do not inhibit their phosphatase activity. Consistently, when expressed in S. cerevisiae, they poorly reproduced the Ppz1-regulatory properties of ScHal3. In contrast, both proteins were functional monogenic PPCDCs. The CnHal3b isoform was crystallized and, for the first time, the 3D-structure of a fungal PPCDC elucidated. Therefore, our work provides the foundations for understanding the regulation and functional role of the Ppz1-Hal3 system in this important pathogenic fungus.

The inhibitory mechanism of Hal3 on the yeast Ppz1 phosphatase: A mutagenesis analysis.

The Ser/Thr protein phosphatase (PPase) Ppz1 is an enzyme related to the ubiquitous type-1 PPases (PP1c) but found only in fungi. It is regulated by an inhibitory subunit, Hal3, which binds to its catalytic domain. Overexpression of Ppz1 is highly toxic for yeast cells, so its de-regulation has been proposed as a target for novel antifungal therapies. While modulation of PP1c by its many regulatory subunits has been extensively characterized, the manner by which Hal3 controls Ppz1 remains unknown. We have used error-prone PCR mutagenesis to construct a library of Ppz1 variants and developed a functional assay to identify mutations affecting the binding or/and the inhibitory capacity of Hal3. We have characterized diverse Ppz1 mutated versions in vivo and in vitro and found that, although they were clearly refractory to Hal3 inhibition, none of them exhibited significant reduction in Hal3 binding. Mapping the mutations strengthened the notion that Hal3 does not interact with Ppz1 through its RVxF-like motif (found in most PP1c regulators). In contrast, the most relevant mutations mapped to a conserved α-helix region used by mammalian Inhibitor-2 to regulate PP1c. Therefore, modulation of PP1c and Ppz1 by their subunits likely differs, but could share some structural features.

Analysis of Two Putative Candida albicans Phosphopantothenoylcysteine Decarboxylase / Protein Phosphatase Z Regulatory Subunits Reveals an Unexpected Distribution of Functional Roles.

Protein phosphatase Z (Ppz) is a fungus specific enzyme that regulates cell wall integrity, cation homeostasis and oxidative stress response. Work on Saccharomyces cerevisiae has shown that the enzyme is inhibited by Hal3/Vhs3 moonlighting proteins that together with Cab3 constitute the essential phosphopantothenoylcysteine decarboxylase (PPCDC) enzyme. In Candida albicans CaPpz1 is also involved in the morphological changes and infectiveness of this opportunistic human pathogen. To reveal the CaPpz1 regulatory context we searched the C. albicans database and identified two genes that, based on the structure of their S. cerevisiae counterparts, were termed CaHal3 and CaCab3. By pull down analysis and phosphatase assays we demonstrated that both of the bacterially expressed recombinant proteins were able to bind and inhibit CaPpz1 as well as its C-terminal catalytic domain (CaPpz1-Cter) with comparable efficiency. The binding and inhibition were always more pronounced with CaPpz1-Cter, indicating a protective effect against inhibition by the N-terminal domain in the full length protein. The functions of the C. albicans proteins were tested by their overexpression in S. cerevisiae. Contrary to expectations we found that only CaCab3 and not CaHal3 rescued the phenotypic traits that are related to phosphatase inhibition by ScHal3, such as tolerance to LiCl or hygromycin B, requirement for external K+ concentrations, or growth in a MAP kinase deficient slt2 background. On the other hand, both of the Candida proteins turned out to be essential PPCDC components and behaved as their S. cerevisiae counterparts: expression of CaCab3 and CaHal3 rescued the cab3 and hal3 vhs3 S. cerevisiae mutations, respectively. Thus, both CaHal3 and CaCab3 retained the PPCDC related functions and have the potential for CaPpz1 inhibition in vitro. The fact that only CaCab3 exhibits its phosphatase regulatory potential in vivo suggests that in C. albicans CaCab3, but not CaHal3, acts as a moonlighting protein.

Complex stability and dynamic subunit interchange modulates the disparate activities of the yeast moonlighting proteins Hal3 and Vhs3.

Saccharomyces cerevisiae Hal3 and Vhs3 are moonlighting proteins, acting both as inhibitors of the serine/threonine protein phosphatase Ppz1 and as subunits (together with Cab3) of the unique heterotrimeric phosphopantothenoylcysteine decarboxylase (PPCDC) enzyme of Hemiascomycetous yeast. Both these roles are essential: PPCDC catalyses the third step of coenzyme A biosynthesis, while Ppz1 inhibition is required for regulation of monovalent cation homeostasis. However, the mechanisms by which these proteins' disparate activities are regulated are not well understood. The PPCDC domains (PDs) of Hal3, Vhs3 and Cab3 constitute the minimum requirement for these proteins to show both PPCDC activity and, in the case of Hal3 and Vhs3, to bind to Ppz1. Using these PD proteins as a model system to study the possibility of dynamic interchange between these roles, we provide evidence that Hal3 binds Ppz1 as a monomer (1:1 stoichiometry), requiring it to de-oligomerize from its usual homo- and heterotrimeric states (the latter having PPCDC activity). This de-oligomerization is made possible by structural features that set Hal3 apart from Vhs3, increasing its ability to undergo monomer exchange. These findings suggest that oligomer interchange may be a significant factor in the functional regulation of these proteins and their various unrelated (moonlighting) functions.

The Schizosaccharomyces pombe fusion gene hal3 encodes three distinct activities.

Saccharomyces cerevisiae Hal3 and Vhs3 are moonlighting proteins, forming an atypical heterotrimeric decarboxylase (PPCDC) required for CoA biosynthesis, and regulating cation homeostasis by inhibition of the Ppz1 phosphatase. The Schizosaccharomyces pombe ORF SPAC15E1.04 (renamed as Sp hal3) encodes a protein whose amino-terminal half is similar to Sc Hal3 whereas its carboxyl-terminal half is related to thymidylate synthase (TS). We show that Sp Hal3 and/or its N-terminal domain retain the ability to bind to and modestly inhibit in vitro S. cerevisiae Ppz1 as well as its S. pombe homolog Pzh1, and also exhibit PPCDC activity in vitro and provide PPCDC function in vivo, indicating that Sp Hal3 is a monogenic PPCDC in fission yeast. Whereas the Sp Hal3 N-terminal domain partially mimics Sc Hal3 functions, the entire protein and its carboxyl-terminal domain rescue the S. cerevisiae cdc21 mutant, thus proving TS function. Additionally, we show that the 70 kDa Sp Hal3 protein is not proteolytically processed under diverse forms of stress and that, as predicted, Sp hal3 is an essential gene. Therefore, Sp hal3 represents a fusion event that joined three different functional activities in the same gene. The possible advantage derived from this surprising combination of essential proteins is discussed.

Addressing the effects of Salmonella internalization in host cell signaling on a reverse-phase protein array.

Through acute enteric infection, Salmonella invades host enterocytes and reproduces intracellularly into specialized vacuolae. This involves changes in host cell signaling elicited by bacterial proteins delivered via type III secretion systems (TTSS). One of the two TTSSs of Salmonella enterica serovar Typhimurium encoded by the Salmonella pathogenicity island-1, triggers bacterial internalization. Among the effector proteins translocated by this TTSS, the GTPase modulator SopE/E2 and the phosphoinositide phosphatase SigD are known to play key roles in these processes. To better understand their contribution to re-programming host cell pathways, we used ZeptoMARK reverse-phase protein array technology, which allows printing 32-sample lysate arrays that can be analyzed with phospho-specific antibodies to evaluate the phosphorylation of signaling proteins. Lysates were obtained at different times after infection of HeLa cells with WT, TTSS-deficient, sopE/E2 and sigD single and double deletants, as well as different sigD Salmonella mutants. Our analysis detected activation of p38, JNK and ERK mitogen-activated protein kinases, mainly dependent on SopE/E2, as well as SigD-dependent phosphorylation of PKB/Akt and its targets GSK-3beta and FKHR/FoxO. This is the first time that reverse-phase protein array technology is used in the cellular microbiology field, demonstrating its value to screen for host signaling events through bacterial infection.