Biology subjects

Luque, R. M.

Publications and source records attributed to Luque, R. M..

7 recordsLinked to original sources

bioRxiv2026

Nuclear exclusion of menin drives functional MEN1 deficiency in non-MEN1 prolactinomas: mouse models and human biopsies

Prolactinomas, the most common secretory pituitary tumour subtype, frequently occur in patients with Multiple Endocrine Neoplasia type 1, caused by germline MEN1 mutations encoding menin. While menin loss is well established in MEN1-associated prolactinomas, its role in sporadic tumours remains unclear. We investigated menin expression, subcellular localization, and downstream signalling in two murine models of non-MEN1 prolactinomas, the dopamine D2-receptor knockout and the hCG{beta}-subunit-overexpressing mice, in which only females develop prolactinoma. Pituitary Men1 expression, analysed by qPCR, remained unchanged despite the genotype, in both sexes. However, in prolactinomas, lactotrophs exhibited a marked loss of nuclear MEN1 immunostained, with protein restricted to the cytoplasm. Male mice pituitaries retained nuclear MEN1 localization regardless their genotype. Loss of nuclear menin in prolactinomas was associated with reduced p27 and Pten expression, increased Ccnd1 expression, and enhanced pAKT. Moreover, by using in vivo pharmacological and surgical approaches we demonstrated that dopamine-agonist treatment preserved nuclear menin in lactotrophs, whereas dopamine blockade or estradiol induced its nuclear loss. Importantly, analysis of human pituitary biopsies confirmed nuclear and cytoplasmic menin localization in lactotrophs from normal pituitaries, and in prolactinomas from both genders following dopamine agonist therapy. However, in a prolactinoma from an untreated female, nuclear menin was partially lost. Therefore, our findings identify a state of functional MEN1-deficiency in sporadic prolactinomas (characterized by preserved MEN1 expression), but its exclusion from the nucleus (linked to activation of proliferative pathways, impaired tumour suppressor signalling, and tumour development) highlights the restoration of nuclear MEN1 localization as a potential therapeutic strategy.

physiology↗

bioRxiv2023

The Exon Junction Complex component EIF4A3 plays a splicing-linked oncogenic role in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide and further research on its biology is needed to fully understand the disease. Dysregulation of alternative RNA splicing is a common hallmark in cancer, including PDAC, which provides an emerging source of knowledge and of novel biomarkers and therapeutic tools. Here, we examined the role of EIF4A3, a core component of the Exon Junction Complex intimately linked to RNA splicing, in pancreatic cancer biology. EIF4A3 is overexpressed in PDAC tissue and associated to clinical parameters of malignancy and poorer patient survival. Mechanistically, exploration of PDAC RNA-seq data unveiled the link of EIF4A3 to diverse malignancy processes, in line with its association to key molecular pathways. Accordingly, EIF4A3 targeting in vitro decreased essential functional tumor features such as proliferation, migration, colony formation and sphere formation, while its in vivo targeting reduced tumor growth. EIF4A3 silencing in PDAC cell lines severely altered its transcriptional and spliceosomic landscapes, as shown by RNA-seq analyses, suggesting a role for EIF4A3 in maintaining RNA homeostasis. Our results indicate that EIF4A3 dysregulation in PDAC has a pleiotropic regulatory role on RNA biology, influencing key cellular functions. This paves the way to explore its potential as a novel biomarker and actionable target candidate for this lethal cancer.

cancer biology↗

bioRxiv2022

Altered virome structrue and function characterization in Helicobacter pylori-driven colorectal carcinogenesis and H. pylori eradication

The understanding of gut virome and its role in Helicobacter pylori-driven colorectal cancer (CRC), as well as the long-term impact of H. pylori eradication via antibiotic treatment on it could contribute to better understanding the mechanisms of the disruption of gut bacteriome homeostasis involved in H. pylori-driven colorectal carcinogenesis and antibiotic therapy for H. pylori eradication. In the dynamic analysis of viral genome shotgun metagenomic of samples from lower gastrointestinal tract of the Apc+/1638N and C57BL/6 mice with H. pylori infection and eradication, stable viral abundance and replacement of bursted unique viral contigs in infected and uninfected Apc+/1638N mice were observed. Temperate phages, which encoding comprehensive microbial functional genes and targeting various susceptible hosts, were expanded extremely prior to cancer exacerbation. In addition, short-term antibiotic exposure for H. pylori eradication was able to alter the gut virome and thrive the antibiotic resistance genes (ARGs) in the viral genome for at least 6 months. Collectively, these results point toward a potential role of the altered, but dynamically balanced gut virome, characterized by the expanded temperate phages, in contributing to the H. pylori-driven CRC, and indicate that viral genome may act as ARG reservoir for the antibiotic resistance of bacteria after the antibiotics therapy to H. pylori eradication.

microbiology↗

bioRxiv2022

Spliceosomic dysregulation unveils NOVA1 as an actionable therapeutic target in pancreatic neuroendocrine tumors

Dysregulation of the splicing machinery is emerging as a hallmark in cancer due to its association with multiple dysfunctions in tumor cells. Inappropriate function of this machinery can generate tumor-driving splicing variants and trigger oncogenic actions. However, its role in pancreatic neuroendocrine tumors (PanNETs) is poorly defined. In this study we aimed to characterize the expression pattern of a set of splicing machinery components in PanNETs, and their relationship with aggressiveness features. A qPCR-based array was first deployed to determine the expression levels of components of the major (n=13) and minor spliceosome (n=4) and associated splicing factors (n=27), using a microfluidic technology in 20 PanNETs and non-tumoral adjacent samples. Subsequently, in vivo and in vitro models were applied to explore the pathophysiological role of NOVA1. Expression analysis revealed that a substantial proportion of splicing machinery components was altered in tumors. Notably, key splicing factors were overexpressed in PanNETs samples, wherein their levels correlated with clinical and malignancy features. Using in vivo and in vitro assays, we demonstrate that one of those altered factors, NOVA1, is tightly related to cell proliferation, alters pivotal signaling pathways and interferes with responsiveness to drug treatment in PanNETs, suggesting a role for this factor in the aggressiveness of these tumors and its suitability as therapeutic target. Altogether, our results unveil a severe alteration of the splicing machinery in PanNETs and identify the putative relevance of NOVA1 in tumor development/progression, which could provide novel avenues to develop diagnostic biomarkers and therapeutic tools for this pathology.

cancer biology↗

bioRxiv2021

A convergent malignant phenotype in B-cell acute lymphoblastic leukemia involving the splicing factor SRRM1

A significant proportion of infant B-cell acute lymphoblastic leukemia (B-ALL) patients remains with a dismal prognosis due to yet undetermined mechanisms. We performed a comprehensive multicohort analysis of gene expression, gene fusions, and RNA splicing alterations to uncover molecular signatures potentially linked to the observed poor outcome. We identified 87 fusions with significant allele frequency across patients and shared functional impacts, suggesting common mechanisms across fusions. We further identified a gene expression signature that predicts high risk independently of the gene fusion background and includes the upregulation of the splicing factor SRRM1. Experiments in B-ALL cell lines provided further evidence for the role of SRRM1 on cell survival, proliferation, and invasion. Supplementary analysis revealed that SRRM1 potentially modulates splicing events associated with poor outcomes through protein-protein interactions with other splicing factors. Our findings reveal a potential convergent mechanism of aberrant RNA processing that sustains a malignant phenotype independently of the underlying gene fusion, and that could potentially complement current clinical strategies in infant B-ALL.

cancer biology↗

bioRxiv2021

Impaired mRNA splicing and proteostasis in preadipocytes in obesity-related metabolic disease

Preadipocytes are crucial for healthy adipose tissue expansion. Preadipocyte differentiation is altered in obese individuals, which has been proposed to contribute to obesity-associated metabolic disturbances. Here, we demonstrate that impaired alternative splicing and dysregulated endoplasmic reticulum (ER)- associated protein degradation (ERAD) represent marker pathways of dysfunctional preadipocytes in obese individuals with insulin resistance (IR)/type 2 diabetes (T2D). Down-regulation of a key member of the major spliceosome, PRFP8/PRP8, as observed in IR/T2D preadipocytes from subcutaneous (SC) fat, prevented adipogenesis by altering both the expression and splicing patterns of adipogenic transcription factors and lipid droplet-related proteins, while adipocyte differentiation was restored upon recovery of PRFP8/PRP8 normal levels. Adipocyte differentiation was also compromised under conditions of ERAD hyperactivation, as occurs in SC and omental (OM) preadipocytes in IR/T2D obesity. Thus, targeting mRNA splicing and ER proteostasis in preadipocytes could improve adipose tissue function and thus contribute to metabolic health in obese individuals.

cell biology↗

bioRxiv2019

The long non-coding RNA GHSROS reprograms prostate cancer cell lines toward a more aggressive phenotype

It is now appreciated that long non-coding RNAs (lncRNAs) are important players in the orchestration of cancer progression. In this study we characterized GHSROS, a human lncRNA gene on the opposite DNA strand (antisense) to the ghrelin receptor gene, in prostate cancer. The lncRNA was upregulated by prostate tumors from different clinical datasets. Consistently, transcriptome data revealed that GHSROS alters the expression of cancer-associated genes. Functional analyses in vitro showed that GHSROS mediates tumor growth, migration, and survival and resistance to the cytotoxic drug docetaxel. Increased cellular proliferation of GHSROS-overexpressing PC3, DU145, and LNCaP prostate cancer cell lines in vitro was recapitulated in a subcutaneous xenograft model. Conversely, in vitro antisense oligonucleotide inhibition of the lncRNA reciprocally regulated cell growth and migration, and gene expression. Notably, GHSROS modulates the expression of PPP2R2C, the loss of which may drive androgen receptor pathway-independent prostate tumor progression in a subset of prostate cancers. Collectively, our findings suggest that GHSROS can reprogram prostate cancer cells toward a more aggressive phenotype and that this lncRNA may represent a potential therapeutic target.

cancer biology↗