LC3A-mediated autophagy elicits PERK-eIF2α-ATF4 axis activation and mitochondrial dysfunction: Exposing vulnerability in aggresome-positive cancer cells.

The unfolded protein response pathways (UPR), autophagy, and compartmentalization of misfolded proteins into inclusion bodies are critical components of the protein quality control network. Among inclusion bodies, aggresomes are particularly intriguing due to their association with cellular survival, drug resistance, and aggresive cancer behavior. Aggresomes are molecular condensates formed when collapsed vimentin cages encircle misfolded proteins before final removal by autophagy. Yet significant gaps persist in the mechanisms governing aggresome formation and elimination in cancer cells. Understanding these mechanisms is crucial, especially considering the involvement of LC3A, a member of the MAP1LC3 family, which plays a unique role in autophagy regulation and has been reported to be epigenetically silenced in many cancers. Herein, we utilized the tetracycline-inducible expression of LC3A to investigate its role in choroid plexus carcinoma cells, which inherently exhibit the presence of aggresomes. Live cell imaging was employed to demonstrate the effect of LC3A expression on aggresome-positive cells, while SILAC-based proteomics identified LC3A-induced protein and pathway alterations. Our findings demonstrated that extended expression of LC3A is associated with cellular senescence. However, the obstruction of lysosomal degradation in this context has a deleterious effect on cellular viability. In response to LC3A-induced autophagy, we observed significant alterations in mitochondrial morphology, reflected by mitochondrial dysfunction and increased ROS production. Furthermore, LC3A expression elicited the activation of the PERK-eIF2α-ATF4 axis of the UPR, underscoring a significant change in the protein quality control network. In conclusion, our results elucidate that LC3A-mediated autophagy alters the protein quality control network, exposing a vulnerability in aggresome-positive cancer cells.

Multi-omics analyses of choroid plexus carcinoma cell lines reveal potential targetable pathways and alterations.

PURPOSE: Choroid plexus carcinomas (CPCs) are extremely rare brain tumors and carry a dismal prognosis. Treatment options are limited and there is an urgent need to develop models to further research. In the present study, we established two CPC cell lines and performed multi-omics analyses. These cell lines serve as valuable models to propose new treatments in these rare but deadly brain tumors. METHODS: Multi-omic profiling including, (i) methylation array (EPIC 850 K), (ii) whole genome sequencing (WGS), (iii) CANCERPLEX cancer genome panel testing, (iv) RNA sequencing (RNA-seq), and (v) proteomics analyses were performed in CCHE-45 and NGT131 cell lines. RESULTS: Both cell lines were classified as methylation class B. Both harbored pathogenic TP53 point mutations; CCHE-45 additionally displayed TP53 loss. Furthermore, alterations of the NOTCH and WNT pathways were also detected in both cell lines. Two protein-coding gene fusions, BZW2-URGCP, and CTTNBP2-ERBB4, mutations of two oncodrivers, GBP-4 and KRTAP-12-2, and several copy number alterations were observed in CCHE-45, but not NGT131. Transcriptome and proteome analysis identified shared and unique signatures, suggesting that variability in choroid plexus carcinoma tumors may exist. The discovered difference's importance and implications highlight the possible diversity of choroid plexus carcinoma and call for additional research to fully understand disease pathogenesis. CONCLUSION: Multi-omics analyses revealed that the two choroid plexus carcinoma cell lines shared TP53 mutations and other common pathway alterations and activation of NOTCH and WNT pathways. Noticeable differences were also observed. These cell lines can serve as valuable models to propose new treatments in these rare but deadly brain tumors.

Aggresomes predict poor outcomes and implicate proteostasis in the pathogenesis of pediatric choroid plexus tumors.

PURPOSE: Protein misfolding and aggregation result in proteotoxic stress and underlie the pathogenesis of many diseases. To overcome proteotoxicity, cells compartmentalize misfolded and aggregated proteins in different inclusion bodies. The aggresome is a paranuclear inclusion body that functions as a storage compartment for misfolded proteins. Choroid plexus tumors (CPTs) are rare neoplasms comprised of three pathological subgroups. The underlying mechanisms of their pathogenesis remain unclear. This study aims to elucidate the prognostic role and the biological effects of aggresomes in pediatric CPTs. METHODS: We examined the presence of aggresomes in 42 patient-derived tumor tissues by immunohistochemistry and we identified their impact on patients' outcomes. We then investigated the proteogenomics signature associated with aggresomes using whole-genome DNA methylation and proteomic analysis to define their role in the pathogenesis of pediatric CPTs. RESULTS: Aggresomes were detected in 64.2% of samples and were distributed among different pathological and molecular subgroups. The presence of aggresomes with different percentages was correlated with patients' outcomes. The ≥ 25% cutoff had the most significant impact on overall and event-free survival (p-value < 0.001) compared to the pathological and the molecular stratifications. CONCLUSIONS: These results support the role of aggresome as a novel prognostic molecular marker for pediatric CPTs that was comparable to the molecular classification in segregating samples into two distinct subgroups, and to the pathological stratification in the prediction of patients' outcomes. Moreover, the proteogenomic signature of CPTs displayed altered protein homeostasis, manifested by enrichment in processes related to protein quality control.

miRNAs as potential game-changers in renal cell carcinoma: Future clinical and medicinal uses.

Renal cell carcinoma (RCC) has the highest mortality rate of all genitourinary cancers, and its prevalence has grown over time. While RCC can be surgically treated and recurrence is only probable in a tiny proportion of patients, early diagnosis is crucial. Mutations in a large number of oncogenes and tumor suppressor genes contribute to pathway dysregulation in RCC. MicroRNAs (miRNAs) have considerable promise as biomarkers for detecting cancer due to their special combination of properties. Several miRNAs have been proposed as a diagnostic or monitoring tool for RCC based on their presence in the blood or urine. Moreover, the expression profile of particular miRNAs has been associated with the response to chemotherapy, immunotherapy, or targeted therapeutic options like sunitinib. The goal of this review is to go over the development, spread, and evolution of RCC. Also, we emphasize the outcomes of studies that examined the use of miRNAs in RCC patients as biomarkers, therapeutic targets, or modulators of responsiveness to treatment modalities.

Histone H3K27M Mutation Overrides Histological Grading in Pediatric Gliomas.

Pediatric high-grade gliomas (HGG) are rare aggressive tumors that present a prognostic and therapeutic challenge. Diffuse midline glioma, H3K27M-mutant is a new entity introduced to HGG in the latest WHO classification. In this study we evaluated the presence of H3K27M mutation in 105 tumor samples histologically classified into low-grade gliomas (LGG) (n = 45), and HGG (n = 60). Samples were screened for the mutation in histone H3.3 and H3.1 variants to examine its prevalence, prognostic impact, and assess its potential clinical value in limited resource settings. H3K27M mutation was detected in 28 of 105 (26.7%) samples, and its distribution was significantly associated with midline locations (p-value < 0.0001) and HGG (p-value = 0.003). Overall and event- free survival (OS and EFS, respectively) of patients with mutant tumors did not differ significantly, neither according to histologic grade (OS p-value = 0.736, EFS p-value = 0.75) nor across anatomical sites (OS p-value = 0.068, EFS p-value = 0.153). Detection of H3K27M mutation in pediatric gliomas provides more precise risk stratification compared to traditional histopathological techniques. Hence, mutation detection should be pursued in all pediatric gliomas. Meanwhile, focusing on midline LGG can be an alternative in lower-middle-income countries to maximally optimize patients' treatment options.

Association of Aggresomes with Survival Outcomes in Pediatric Medulloblastoma.

Aggresomes are inclusion bodies for misfolded/aggregated proteins. Despite the role of misfolded/aggregated proteins in neurological disorders, their role in cancer pathogenesis is poorly defined. In the current study we aimed to investigate whether aggresomes-positivity could be used to improve the disease subclassification and prognosis prediction of pediatric medulloblastoma. Ninety three pediatric medulloblastoma tumor samples were retrospectively stratified into three molecular subgroups; WNT, SHH and non-WNT/non-SHH, using immunohistochemistry and Multiplex Ligation Probe Amplification. Formation of aggresomes were detected using immunohistochemistry. Overall survival (OS) and event-free survival (EFS) were determined according to risk stratification criteria. Multivariate Cox regression analyses were carried out to exclude confounders. Aggresomes formation was detected in 63.4% (n = 59/93) of samples. Aggresomes were non-randomly distributed among different molecular subgroups (P = 0.00002). Multivariate Cox model identified aggresomes' percentage at ≥20% to be significantly correlated with patient outcome in both OS (HR = 3.419; 95% CI, 1.30-8.93; P = 0.01) and EFS (HR = 3; 95% CI, 1.19-7.53; P = 0.02). The presence of aggresomes in ≥20% of the tumor identified poor responders in standard risk patients; OS (P = 0.02) and EFS (P = 0.06), and significantly correlated with poor outcome in non-WNT/non-SHH molecular subgroup; OS (P = 0.0002) and EFS (P = 0.0004).

Arkypallidal Cells Send a Stop Signal to Striatum.

The suppression of inappropriate actions is critical for flexible behavior. Cortical-basal ganglia networks provide key gating mechanisms for action suppression, yet the specific roles of neuronal subpopulations are poorly understood. Here, we examine Arkypallidal (''Arky'') and Prototypical (''Proto'') globus pallidus neurons during a Stop task, which requires abrupt cancellation of an imminent action. We first establish that Arky neurons can be identified by their firing properties across the natural sleep/wake cycle. We then show that Stop responses are earlier and stronger in the Arky compared to the Proto subpopulation. In contrast to other basal ganglia neurons, pallidal Stop responses are selective to Stop, rather than Go, cues. Furthermore, the timing of these Stop responses matches the suppression of developing striatal Go-related activity. Our results support a two-step model of action suppression: actions-inpreparation are first paused via a subthalamic-nigral pathway, then cancelled via Arky GABAergic projections to striatum.