The yin and yang of chromosomal instability in prostate cancer.

Metastatic prostate cancer remains an incurable lethal disease. Studies indicate that prostate cancer accumulates genomic changes during disease progression and displays the highest levels of chromosomal instability (CIN) across all types of metastatic tumours. CIN, which refers to ongoing chromosomal DNA gain or loss during mitosis, and derived aneuploidy, are known to be associated with increased tumour heterogeneity, metastasis and therapy resistance in many tumour types. Paradoxically, high CIN levels are also proposed to be detrimental to tumour cell survival, suggesting that cancer cells must develop adaptive mechanisms to ensure their survival. In the context of prostate cancer, studies indicate that CIN has a key role in disease progression and might also offer a therapeutic vulnerability that can be pharmacologically targeted. Thus, a comprehensive evaluation of the causes and consequences of CIN in prostate cancer, its contribution to aggressive advanced disease and a better understanding of the acquired CIN tolerance mechanisms can translate into new tumour classifications, biomarker development and therapeutic strategies.

Master Transcription Factor Reprogramming Unleashes Selective Translation Promoting Castration Resistance and Immune Evasion in Lethal Prostate Cancer.

Signaling rewiring allows tumors to survive therapy. Here we show that the decrease of the master regulator microphthalmia transcription factor (MITF) in lethal prostate cancer unleashes eukaryotic initiation factor 3B (eIF3B)-dependent translation reprogramming of key mRNAs conferring resistance to androgen deprivation therapy (ADT) and promoting immune evasion. Mechanistically, MITF represses through direct promoter binding eIF3B, which in turn regulates the translation of specific mRNAs. Genome-wide eIF3B enhanced cross-linking immunoprecipitation sequencing (eCLIP-seq) showed specialized binding to a UC-rich motif present in subsets of 5' untranslated regions. Indeed, translation of the androgen receptor and major histocompatibility complex I (MHC-I) through this motif is sensitive to eIF3B amount. Notably, pharmacologic targeting of eIF3B-dependent translation in preclinical models sensitizes prostate cancer to ADT and anti-PD-1 therapy. These findings uncover a hidden connection between transcriptional and translational rewiring promoting therapy-refractory lethal prostate cancer and provide a druggable mechanism that may transcend into effective combined therapeutic strategies. SIGNIFICANCE: Our study shows that specialized eIF3B-dependent translation of specific mRNAs released upon downregulation of the master transcription factor MITF confers castration resistance and immune evasion in lethal prostate cancer. Pharmacologic targeting of this mechanism delays castration resistance and increases immune-checkpoint efficacy. This article is featured in Selected Articles from This Issue, p. 2489.

Whole-genome sequencing reveals changes in genomic diversity and distinctive repertoires of T3SS and T6SS effector candidates in Chilean clinical Campylobacter strains.

Campylobacter is the leading cause of bacterial gastroenteritis worldwide and an emerging and neglected pathogen in South America. This zoonotic pathogen colonizes the gastrointestinal tract of a wide range of mammals and birds, with poultry as the most important reservoir for human infections. Apart from its high morbidity rates, the emergence of resistant strains is of global concern. The aims of this work were to determine genetic diversity, presence of antimicrobial resistance determinants and virulence potential of Campylobacter spp. isolated from patients with acute gastrointestinal disease at 'Clinica Alemana', Santiago de Chile. The study considered the isolation of Campylobacter spp., from stool samples during a 20-month period (January 2020 to September 2021). We sequenced (NextSeq, Illumina) and performed an in-depth analysis of the genome sequences of 88 Campylobacter jejuni and 2 Campylobacter coli strains isolated from clinical samples in Chile. We identified a high genetic diversity among C. jejuni strains and the emergence of prevalent clonal complexes, which were not identified in our previous reports. While ~40% of strains harbored a mutation in the gyrA gene associated with fluoroquinolone resistance, no macrolide-resistance determinants were detected. Interestingly, gene clusters encoding virulence factors such as the T6SS or genes associated with long-term sequelae such as Guillain-Barré syndrome showed lineage-relatedness. In addition, our analysis revealed a high degree of variability regarding the presence of fT3SS and T6SS effector proteins in comparison to type strains 81-176, F38011, and NCTC 11168 and 488. Our study provides important insights into the molecular epidemiology of this emerging foodborne pathogen. In addition, the differences observed regarding the repertoire of fT3SS and T6SS effector proteins could have an impact on the pathogenic potential and transmissibility of these Latin American isolates, posing another challenge in characterizing the infection dynamics of this emergent and neglected bacterial pathogen.

Vibrio type III secretion system 2 is not restricted to the Vibrionaceae and encodes differentially distributed repertoires of effector proteins.

Vibrio parahaemolyticus is the leading cause of seafood-borne gastroenteritis worldwide. A distinctive feature of the O3:K6 pandemic clone, and its derivatives, is the presence of a second, phylogenetically distinct, type III secretion system (T3SS2) encoded within the genomic island VPaI-7. The T3SS2 allows the delivery of effector proteins directly into the cytosol of infected eukaryotic cells to subvert key host-cell processes, critical for V. parahaemolyticus to colonize and cause disease. Furthermore, the T3SS2 also increases the environmental fitness of V. parahaemolyticus in its interaction with bacterivorous protists; hence, it has been proposed that it contributed to the global oceanic spread of the pandemic clone. Several reports have identified T3SS2-related genes in Vibrio and non-Vibrio species, suggesting that the T3SS2 gene cluster is not restricted to the Vibrionaceae and can mobilize through horizontal gene transfer events. In this work, we performed a large-scale genomic analysis to determine the phylogenetic distribution of the T3SS2 gene cluster and its repertoire of effector proteins. We identified putative T3SS2 gene clusters in 1130 bacterial genomes from 8 bacterial genera, 5 bacterial families and 47 bacterial species. A hierarchical clustering analysis allowed us to define six T3SS2 subgroups (I-VI) with different repertoires of effector proteins, redefining the concepts of T3SS2 core and accessory effector proteins. Finally, we identified a subset of the T3SS2 gene clusters (subgroup VI) that lacks most T3SS2 effector proteins described to date and provided a list of 10 novel effector candidates for this subgroup through bioinformatic analysis. Collectively, our findings indicate that the T3SS2 extends beyond the family Vibrionaceae and suggest that different effector protein repertories could have a differential impact on the pathogenic potential and environmental fitness of each bacterium that has acquired the Vibrio T3SS2 gene cluster.

Mechanisms of chromosomal instability (CIN) tolerance in aggressive tumors: surviving the genomic chaos.

Chromosomal instability (CIN) is a pervasive feature of human cancers involved in tumor initiation and progression and which is found elevated in metastatic stages. CIN can provide survival and adaptation advantages to human cancers. However, too much of a good thing may come at a high cost for tumor cells as excessive degree of CIN-induced chromosomal aberrations can be detrimental for cancer cell survival and proliferation. Thus, aggressive tumors adapt to cope with ongoing CIN and most likely develop unique susceptibilities that can be their Achilles' heel. Determining the differences between the tumor-promoting and tumor-suppressing effects of CIN at the molecular level has become one of the most exciting and challenging aspects in cancer biology. In this review, we summarized the state of knowledge regarding the mechanisms reported to contribute to the adaptation and perpetuation of aggressive tumor cells carrying CIN. The use of genomics, molecular biology, and imaging techniques is significantly enhancing the understanding of the intricate mechanisms involved in the generation of and adaptation to CIN in experimental models and patients, which were not possible to observe decades ago. The current and future research opportunities provided by these advanced techniques will facilitate the repositioning of CIN exploitation as a feasible therapeutic opportunity and valuable biomarker for several types of human cancers.

Harnessing transcriptionally driven chromosomal instability adaptation to target therapy-refractory lethal prostate cancer.

Metastatic prostate cancer (PCa) inevitably acquires resistance to standard therapy preceding lethality. Here, we unveil a chromosomal instability (CIN) tolerance mechanism as a therapeutic vulnerability of therapy-refractory lethal PCa. Through genomic and transcriptomic analysis of patient datasets, we find that castration and chemotherapy-resistant tumors display the highest CIN and mitotic kinase levels. Functional genomics screening coupled with quantitative phosphoproteomics identify MASTL kinase as a survival vulnerability specific of chemotherapy-resistant PCa cells. Mechanistically, MASTL upregulation is driven by transcriptional rewiring mechanisms involving the non-canonical transcription factors androgen receptor splice variant 7 and E2F7 in a circuitry that restrains deleterious CIN and prevents cell death selectively in metastatic therapy-resistant PCa cells. Notably, MASTL pharmacological inhibition re-sensitizes tumors to standard therapy and improves survival of pre-clinical models. These results uncover a targetable mechanism promoting high CIN adaptation and survival of lethal PCa.

Endogamia de comités editoriales en revistas peruanas de la salud

Introducción: las revistas científicas son el instrumento perfecto para comunicar resultados del proceso de investigación y transmitir el conocimiento. El comité editorial es un equipo de expertos de vital importancia en el funcionamiento de una revista científica. Sin embargo, una frecuente práctica editorial es la publicación de manuscritos en las revistas que editan. Por ello, se buscó determinar cuál es la frecuencia de la endogamia editorial en las revistas peruanas del área de la salud. Métodos: se realizó una revisión de los artículos publicados por miembros del comité editorial de 26 revistas peruanas entre el 2016 y 2019. Se realizó una evaluación de los manuscritos provenientes del comité editorial, así como un análisis de asociación entre el estado de indexación en dos bases de datos regionales; además, cómo esta influye en la frecuencia de endogamia de cada revista. Resultados: durante el periodo evaluado se publicaron 2.885 manuscritos, de los cuales 520 tenían como autores a miembros del comité editorial. El tipo de contribución más frecuente fue el artículo original. La endogamia en los años 2016 al 2018, así como un mayor porcentaje de endogamia por fascículo, fue estadísticamente mayor en las revistas pertenecientes al directorio Latindex. Conclusión: las revistas peruanas del área de la salud tienen frecuencias heterogéneas de endogamia editorial. Las revistas incluidas en el directorio Latindex presentan una mayor frecuencia de esta práctica editorial frente a las revistas que pertenecen a la base de datos SciELO-Perú.

SUMMARY Introduction: Scientific journals are the perfect instrument to communicate results of the research process and transmit knowledge. The editorial board is a team of experts of vital importance in the operation of a scientific journal, however, a frequent editorial practice is the publication of manuscripts in the journals they edit; therefore, we sought to determine the frequency of editorial inbreeding in Peruvian journals in the health area. Methods: A review of the articles published by members of the editorial board of 26 Peruvian journals between 2016 and 2019 was performed, evaluating the manuscripts from the editorial board, as well as analysis of association between the status of indexation in two regional databases and how this influences the frequency of inbreeding in each journal. Results: During the period evaluated, 2885 manuscripts were published, of which 520 had authors of the editorial board as authors. The most frequent type of contribution was the original article. Inbreeding in the years 2016 to 2018, as well as a higher percentage of inbreeding per issue, was statistically higher in the journals belonging to the Latindex directory. Conclusion: Peruvian journals in the health area have heterogeneous frequencies of editorial inbreeding. The journals included in the Latindex directory present higher frequency in editorial inbreeding, compared to journals included in the SciELO-Peru database.

Redefining cancer of unknown primary: Is precision medicine really shifting the paradigm?

The concept of Cancer of Unknown Primary (CUP) has evolved with the advent of medical oncology. CUP can be difficult to diagnose and represents 2 to 5% of new cancers, therefore not exceptionally rare. Within CUPs can be identified a subset of favourable prognosis tumours, however the vast majority of CUP patients belongs to a poor prognosis group. CUP features significant oncological challenges, such as unravelling biological and transversal issues, and most importantly, improving patient's outcomes. In that regard, CUP patients' outcomes regrettably showed minimal improvement for decades and CUP remains a cancer group of very poor prognosis. The biology of CUP has two main hypotheses. One is that CUP is a subgroup of a given primary cancer, where the primary is present but cannot be seen due to its small size. The other, the "true" CUP hypothesis, states that CUP share features that make them a specific entity, whatever their tissue of origin. A true biological signature has not yet been described, but chromosomal instability is a hallmark of poor prognosis CUP group. Precision oncology, despite achieving identifying the putative origin of the CUP, so far failed to globally improve outcomes of patients. Targeting molecular pathways based on molecular analysis in CUP management is under investigation. Immunotherapy has not shown ground-breaking results, to date. Accrual is also a crucial issue in CUP trials. Herein we review CUP history, biological features and remaining questions in CUP biology, the two main approaches of molecular oncology in CUP management, in order to draw perspectives in the enormous challenge of improving CUP patient outcomes.

Genomic analysis of the diversity, antimicrobial resistance and virulence potential of clinical Campylobacter jejuni and Campylobacter coli strains from Chile.

Campylobacter jejuni and Campylobacter coli are the leading cause of human gastroenteritis in the industrialized world and an emerging threat in developing countries. The incidence of campylobacteriosis in South America is greatly underestimated, mostly due to the lack of adequate diagnostic methods. Accordingly, there is limited genomic and epidemiological data from this region. In the present study, we performed a genome-wide analysis of the genetic diversity, virulence, and antimicrobial resistance of the largest collection of clinical C. jejuni and C. coli strains from Chile available to date (n = 81), collected in 2017-2019 in Santiago, Chile. This culture collection accounts for more than one third of the available genome sequences from South American clinical strains. cgMLST analysis identified high genetic diversity as well as 13 novel STs and alleles in both C. jejuni and C. coli. Pangenome and virulome analyses showed a differential distribution of virulence factors, including both plasmid and chromosomally encoded T6SSs and T4SSs. Resistome analysis predicted widespread resistance to fluoroquinolones, but low rates of erythromycin resistance. This study provides valuable genomic and epidemiological data and highlights the need for further genomic epidemiology studies in Chile and other South American countries to better understand molecular epidemiology and antimicrobial resistance of this emerging intestinal pathogen.

Modulation of Escherichia coli Translation by the Specific Inactivation of tRNAGly Under Oxidative Stress.

Bacterial oxidative stress responses are generally controlled by transcription factors that modulate the synthesis of RNAs with the aid of some sRNAs that control the stability, and in some cases the translation, of specific mRNAs. Here, we report that oxidative stress additionally leads to inactivation of tRNAGly in Escherichia coli, inducing a series of physiological changes. The observed inactivation of tRNAGly correlated with altered efficiency of translation of Gly codons, suggesting a possible mechanism of translational control of gene expression under oxidative stress. Changes in translation also depended on the availability of glycine, revealing a mechanism whereby bacteria modulate the response to oxidative stress according to the prevailing metabolic state of the cells.

Draft Whole-Genome Sequences of 51 Campylobacter jejuni and 12 Campylobacter coli Clinical Isolates from Chile.

Campylobacter species are the leading cause of gastroenteritis worldwide and an emerging threat in developing countries. Here, we report the draft whole-genome sequences of 51 Campylobacter jejuni and 12 Campylobacter coli strains isolated from patients with gastroenteritis in Santiago, Chile.

Comparison between intravenous lidocaine and fentanyl on cough reflex and sympathetic response during endotracheal intubation in dogs.

OBJECTIVE: To compare the effects of intravenous (IV) lidocaine and fentanyl on the cough reflex and autonomic response during endotracheal intubation in dogs. STUDY DESIGN: Randomized, blinded, superiority clinical trial. ANIMALS: A total of 46 client-owned dogs undergoing magnetic resonance imaging. METHODS: After intramuscular methadone (0.2 mg kg-1), dogs were randomized to be administered either IV lidocaine (2 mg kg-1; group L) or fentanyl (7 µg kg-1; group F). After 5 minutes, alfaxalone was administered until endotracheal intubation was possible (1 mg kg-1 IV over 40 seconds followed by 0.4 mg kg-1 increments to effect). Total dose of alfaxalone was recorded and cough reflex at endotracheal intubation was scored. Heart rate (HR) was continuously recorded, Doppler systolic arterial blood pressure (SAP) was measured every 20 seconds. Vasovagal tonus index (VVTI) and changes (Δ) in HR, SAP and VVTI between pre-intubation and intubation were calculated. Groups were compared using univariate and multivariate analysis. Statistical significance was set as p < 0.05. RESULTS: Group F included 22 dogs and group L 24 dogs. The mean (± standard deviation) alfaxalone dose was 1.1 (± 0.2) and 1.35 (± 0.3) mg kg-1 in groups F and L, respectively (p = 0.0008). At intubation, cough was more likely in group L (odds ratio = 11.3; 95% confidence intervals, 2.1 - 94.2; p = 0.01) and HR increased in 87.5% and 54.5% of groups L and F, respectively (p = 0.02). The median (range) ΔHR between pre-intubation and intubation was higher (13.1%; - 4.3 to + 55.1) in group L (p = 0.0021). Between groups, SAP and VVTI were similar. CONCLUSION AND CLINICAL RELEVANCE: At the stated doses, whilst reducing the alfaxalone dose, fentanyl is superior to lidocaine in suppressing the cough reflex and blunting the increase in HR at endotracheal intubation in dogs premedicated with methadone.

Cellular rewiring in lethal prostate cancer: the architect of drug resistance.

Over the past 5 years, the advent of combination therapeutic strategies has substantially reshaped the clinical management of patients with advanced prostate cancer. However, most of these combination regimens were developed empirically and, despite offering survival benefits, are not enough to halt disease progression. Thus, the development of effective therapeutic strategies that target the mechanisms involved in the acquisition of drug resistance and improve clinical trial design are an unmet clinical need. In this context, we hypothesize that the tumour engineers a dynamic response through the process of cellular rewiring, in which it adapts to the therapy used and develops mechanisms of drug resistance via downstream signalling of key regulatory cascades such as the androgen receptor, PI3K-AKT or GATA2-dependent pathways, as well as initiation of biological processes to revert tumour cells to undifferentiated aggressive states via phenotype switching towards a neuroendocrine phenotype or acquisition of stem-like properties. These dynamic responses are specific for each patient and could be responsible for treatment failure despite multi-target approaches. Understanding the common stages of these cellular rewiring mechanisms to gain a new perspective on the molecular underpinnings of drug resistance might help formulate novel combination therapeutic regimens.

Antimicrobial resistance in E. coli isolated from dairy calves and bedding material.

INTRODUCTION: E. coli is a ubiquitous bacterium commonly used as a sentinel in antimicrobial resistance studies. Here, E. coli was isolated from three groups (sick calves, healthy calves and bedding material), to assess the presence of antimicrobial resistance, describe resistance profiles, and compare these resistances among groups. MATERIAL AND METHODS: Samples were collected from calves and calving pens from 20 dairy farms. Using the disc diffusion method, E. coli isolates were screened for antimicrobial resistance against seven antimicrobials: Amoxicillin, Ceftiofur, Gentamicin, Enrofloxacin, Trimethoprim-sulfamethoxazole, Florfenicol and Oxytetracycline. Isolates resistant to all these seven antimicrobials were tested again against an extended 19 antimicrobial drug panel and for the presence of the most common E. coli pathogenicity genes through PCR. RESULTS & DISCUSSION: Three hundred forty-nine E. coli isolates were obtained; most isolates were resistant to a single antimicrobial, but 2.3% (8) were resistant to 16 to 19 of the antimicrobials tested. The group with the highest percentage of multiresistant isolates was the calves with diarrhea group. Younger calves provided samples with higher antimicrobial resistance levels. CONCLUSIONS: There is a high rate of antimicrobial resistance in dairy farms calving pens. These bacteria could not only be a resistance gene reservoir, but also could have the potential to spread these determinants through horizontal gene transfer to other susceptible bacteria. Measures should be taken to protect colonization of younger calves, based on hygienic measures and proper management.

Estudio transversal de función auricular izquierda mediante speckle tracking en cirrosis hepática / Left Atrial Function by Speckle Tracking in Liver Cirrhosis. A Cross-sectional Study

RESUMEN Introducción: La miocardiopatía del cirrótico es la disfunción sistólica y/o diastólica del ventrículo izquierdo en reposo o estrés, en ausencia de otras condiciones cardiovasculares que lo explique, y que empeora el pronóstico post trasplante u otros procedimientos quirúrgicos hepáticos. Objetivo: El objetivo del estudio fue caracterizar la función auricular izquierda con speckle tracking en pacientes cirróticos. Material y métodos: Se incluyeron 99 pacientes consecutivos con cirrosis hepática de diferente etiología. A todos pacientes se les realizó estudio ecocardiográfico en reposo con medición de la función ventricular y auricular isquierda con técnicas tradicionales, mediciones tridimensionales y speckle tracking. Resultados: La mediana de edad fue de 50.9 años y 40% de los pacientes fueron hombres. No se observaron alteraciones de la función sistólica del ventrículo izquierdo. El 27% de los pacientes presentó disfunción diastólica y dilatación de la aurícula izquierda, está última con incremento significativo según el estadío Child y se observaron alteraciones de la función de bomba de la aurícula izquierda en el 29% de los casos. Conclusión: Los pacientes cirróticos presentan disfunción diastólica ventricular izquierda y alteraciones de la función sistólica de la aurícula izquierda medida por speckle tracking.

ABSTRACT Background: Cirrhotic cardiomyopathy is the systolic and/or diastolic dysfunction of the left ventricle at rest or stress, in the absence of other cardiovascular conditions, and worsens the prognosis after transplant or other liver surgical procedures. Objective: The aim of the study was to characterize left atrial function with speckle tracking in cirrhotic patients. Methods: Ninety-nine consecutive patients with liver cirrhosis of different etiology were included in the study. All patients underwent rest echocardiographic evaluation with measurement of left ventricular and atrial function using traditional techniques, three-dimensional measurements and speckle tracking. Results: Median age was 50.9 years and 40% were men. No alterations of left ventricular systolic function were observed. Twenty-seven percent of patients had diastolic dysfunction and dilatation of the left atrium, the latter with a significant increase according to the Child stage and left atrial pump function was altered in 29% of cases. Conclusion: Cirrhotic patients present left ventricular diastolic dysfunction and alterations of left atrial systolic function measured by speckle tracking.

Isolation and Characterization of Tumor-initiating Cells from Sarcoma Patient-derived Xenografts.

The existence and importance of tumor-initiating cells (TICs) have been supported by increasing evidence during the past decade. These TICs have been shown to be responsible for tumor initiation, metastasis, and drug resistance. Therefore, it is important to develop specific TIC-targeting therapy in addition to current chemotherapy strategies, which mostly focus on the bulk of non-TICs. In order to further understand the mechanism behind the malignancy of TICs, we describe a method to isolate and to characterize TICs in human sarcomas. Herein, we show a detailed protocol to generate patient-derived xenografts (PDXs) of human sarcomas and to isolate TICs by fluorescence-activated cell sorting (FACS) using human leukocyte antigen class I (HLA-1) as a negative marker. Also, we describe how to functionally characterize these TICs, including a sphere formation assay and a tumor formation assay, and to induce differentiation along mesenchymal pathways. The isolation and characterization of PDX TICs provide clues for the discovery of potential targeting therapy reagents. Moreover, increasing evidence suggests that this protocol may be further extended to isolate and characterize TICs from other types of human cancers.

Nuclear Pores Promote Lethal Prostate Cancer by Increasing POM121-Driven E2F1, MYC, and AR Nuclear Import.

Nuclear pore complexes (NPCs) regulate nuclear-cytoplasmic transport, transcription, and genome integrity in eukaryotic cells. However, their functional roles in cancer remain poorly understood. We interrogated the evolutionary transcriptomic landscape of NPC components, nucleoporins (Nups), from primary to advanced metastatic human prostate cancer (PC). Focused loss-of-function genetic screen of top-upregulated Nups in aggressive PC models identified POM121 as a key contributor to PC aggressiveness. Mechanistically, POM121 promoted PC progression by enhancing importin-dependent nuclear transport of key oncogenic (E2F1, MYC) and PC-specific (AR-GATA2) transcription factors, uncovering a pharmacologically targetable axis that, when inhibited, decreased tumor growth, restored standard therapy efficacy, and improved survival in patient-derived pre-clinical models. Our studies molecularly establish a role of NPCs in PC progression and give a rationale for NPC-regulated nuclear import targeting as a therapeutic strategy for lethal PC. These findings may have implications for understanding how NPC deregulation contributes to the pathogenesis of other tumor types.