Integrated transcriptomics uncovers an enhanced association between the prion protein gene expression and vesicle dynamics signatures in glioblastomas.

BACKGROUND: Glioblastoma (GBM) is an aggressive brain tumor that exhibits resistance to current treatment, making the identification of novel therapeutic targets essential. In this context, cellular prion protein (PrPC) stands out as a potential candidate for new therapies. Encoded by the PRNP gene, PrPC can present increased expression levels in GBM, impacting cell proliferation, growth, migration, invasion and stemness. Nevertheless, the exact molecular mechanisms through which PRNP/PrPC modulates key aspects of GBM biology remain elusive. METHODS: To elucidate the implications of PRNP/PrPC in the biology of this cancer, we analyzed publicly available RNA sequencing (RNA-seq) data of patient-derived GBMs from four independent studies. First, we ranked samples profiled by bulk RNA-seq as PRNPhigh and PRNPlow and compared their transcriptomic landscape. Then, we analyzed PRNP+ and PRNP- GBM cells profiled by single-cell RNA-seq to further understand the molecular context within which PRNP/PrPC might function in this tumor. We explored an additional proteomics dataset, applying similar comparative approaches, to corroborate our findings. RESULTS: Functional profiling revealed that vesicular dynamics signatures are strongly correlated with PRNP/PrPC levels in GBM. We found a panel of 73 genes, enriched in vesicle-related pathways, whose expression levels are increased in PRNPhigh/PRNP+ cells across all RNA-seq datasets. Vesicle-associated genes, ANXA1, RAB31, DSTN and SYPL1, were found to be upregulated in vitro in an in-house collection of patient-derived GBM. Moreover, proteome analysis of patient-derived samples reinforces the findings of enhanced vesicle biogenesis, processing and trafficking in PRNPhigh/PRNP+ GBM cells. CONCLUSIONS: Together, our findings shed light on a novel role for PrPC as a potential modulator of vesicle biology in GBM, which is pivotal for intercellular communication and cancer maintenance. We also introduce GBMdiscovery, a novel user-friendly tool that allows the investigation of specific genes in GBM biology.

Unconventional Protein Secretion in Brain Tumors Biology: Enlightening the Mechanisms for Tumor Survival and Progression.

Non-canonical secretion pathways, collectively known as unconventional protein secretion (UPS), are alternative secretory mechanisms usually associated with stress-inducing conditions. UPS allows proteins that lack a signal peptide to be secreted, avoiding the conventional endoplasmic reticulum-Golgi complex secretory pathway. Molecules that generally rely on the canonical pathway to be secreted may also use the Golgi bypass, one of the unconventional routes, to reach the extracellular space. UPS studies have been increasingly growing in the literature, including its implication in the biology of several diseases. Intercellular communication between brain tumor cells and the tumor microenvironment is orchestrated by various molecules, including canonical and non-canonical secreted proteins that modulate tumor growth, proliferation, and invasion. Adult brain tumors such as gliomas, which are aggressive and fatal cancers with a dismal prognosis, could exploit UPS mechanisms to communicate with their microenvironment. Herein, we provide functional insights into the UPS machinery in the context of tumor biology, with a particular focus on the secreted proteins by alternative routes as key regulators in the maintenance of brain tumors.

Multifaceted WNT Signaling at the Crossroads Between Epithelial-Mesenchymal Transition and Autophagy in Glioblastoma.

Tumor cells can employ epithelial-mesenchymal transition (EMT) or autophagy in reaction to microenvironmental stress. Importantly, EMT and autophagy negatively regulate each other, are able to interconvert, and both have been shown to contribute to drug-resistance in glioblastoma (GBM). EMT has been considered one of the mechanisms that confer invasive properties to GBM cells. Autophagy, on the other hand, may show dual roles as either a GBM-promoter or GBM-suppressor, depending on microenvironmental cues. The Wingless (WNT) signaling pathway regulates a plethora of developmental and biological processes such as cellular proliferation, adhesion and motility. As such, GBM demonstrates deregulation of WNT signaling in favor of tumor initiation, proliferation and invasion. In EMT, WNT signaling promotes induction and stabilization of different EMT activators. WNT activity also represses autophagy, while nutrient deprivation induces ß-catenin degradation via autophagic machinery. Due to the importance of the WNT pathway to GBM, and the role of WNT signaling in EMT and autophagy, in this review we highlight the effects of the WNT signaling in the regulation of both processes in GBM, and discuss how the crosstalk between EMT and autophagy may ultimately affect tumor biology.

[Urolithiasis in children: diagnostic difficulties]. / Urolitiasi del bambino: difficoltà diagnostiche.

The incidence of urolithiasis in children has been steadily increasing in developed countries mainly due to changes in dietary habits. The occurrence of symptoms suggestive of urolithiasis in children with urinary solute abnormalities predisposing to stone formation but with normal renal ultrasound and X-ray plain film is approximately 9 times higher than the occurrence of overt stone disease. This discrepancy may depend on several factors, for example: the limited sensitivity of these methods of imaging, the presence of urinary crystals that, while not detectable with imaging, injure bladder epithelium, in addition to imaging studies performed after the passage of calculi giving negative results. Correct technique during urine collection is also essential for diagnosis. Urolithiasis must be suspected in the face of abdominal pain even central or diffuse pain in younger children when there is a positive family history even though specific urinary symptoms such hematuria and dysuria may be lacking.

Factors increasing the risk for stone formation in adult patients with cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis (CF) are at high risk of nephrolithiasis (NL), but controversy still exists in terms of causes, including low urine output, hypercalciuria, hyperoxaluria, hyperuricosuria and hypocitraturia. Moreover, heterozygotes (H-CF), which may exhibit altered renal concentrating and diluting ability, have never studied so far. We, therefore, evaluated the metabolic and physicochemical data of adult CF and H-CF patients, comparing them to controls (C). METHODS: Twenty-nine CF patients (16 females, aged 28.4 +/- 7.1 years), 20 H-CF (12 females, aged 58.6 +/- 6.3 years) and 30 C (19 females, aged 39.1 +/- 11.5 years) underwent kidney ultrasound and metabolic evaluation to assess stone risk profile. RESULTS: There was a 21% prevalence of NL in CF vs 15% in H-CF. The CF group had elevated uric acid, but no other serological differences compared with the H-CF and C group. Conversely, the citrate and oxalate content in the urine differed significantly, being lower and higher, respectively. These changes held after correction for urine creatinine. Consequently, urine specimens were more supersaturated with calcium oxalate, despite exhibiting no differences for other relevant constituents. Uric acid increased only after normalization for the body weight and urine creatinine. Lower urine volume and more acidic pH produced mild supersaturation with uric acid in samples from CF, while urine from both H-CF and C remained undersaturated. H-CF had only minor increases in both urine oxalate and calcium oxalate supersaturation. CONCLUSIONS: This study confirms a high prevalence of kidney stones among CF patients associated with supersaturated urine. Their longer survival justifies diets and/or medications aimed at reducing the risk of forming stones.