KLHL5 knockdown increases cellular sensitivity to anticancer drugs

Plasma Exosome miR-203a-3p is a Potential Liquid Biopsy Marker for Assessing Tumor Progression in Breast Cancer Patients

Background

Timely detection of tumor progression in breast cancer (BC) patients is critical for therapeutic management and prognosis. Plasma exosomal miRNAs are potential liquid biopsy markers for monitoring tumor progression, but their roles in BC remain unclear.

Methods

In the TCGA database, we first screened for miRNAs significantly associated with BC progression by comparing miRNA expression in para-carcinoma tissues, stage I BC tissues, and stage II-III BC tissues (n = 1026). Cox regression analyses and survival analyses were performed on candidate miRNAs to explore their prognostic value (n = 848). KEGG, GO, and PPI analyses were used to identify enriched pathways associated with cancer. Finally, the potential of candidate miRNAs as liquid biopsy markers was evaluated by sequencing and analyzing plasma exosomal miRNAs from our collection of 45 BC patients (14 in stage I, 31 in stage II-III) and 5 healthy controls, combined with qRT-PCR analysis to assess the correlation of candidate gene expression in plasma exosomes and BC tissues.

Results

We found that only miR-203a-3p was progressively elevated with BC progression and was associated with poor prognosis in the TCGA dataset. Its potential target genes were enriched in pathways related to tumor progression, and the downregulation of 48 of these genes was associated with poor prognosis. More importantly, plasma exosomal miR-203a-3p was also found to gradually increase with BC progression, and its expression was positively correlated with miR-203a-3p in BC tissues. This result suggests that plasma exosomal miR-203a-3p may reflect the expression of miR-203a-3p in tumor tissues and serve as a potential liquid biopsy marker for monitoring BC progressions.

Conclusion

We found for the first time that elevated miR-203a-3p was associated with BC progression and poor prognosis. Our findings suggested that plasma exosomal miR-203a-3p could hold potential as a liquid biopsy marker for evaluating BC progression in patients.

KLHL20 and its role in cell homeostasis: A new perspective and therapeutic potential

Ubiquitin ligases are proteins with the ability to trigger non-degradative signaling or proteasomal destruction by attracting substrates and facilitating ubiquitin transfer onto target proteins. Over the years, there has been a continuous discovery of new ubiquitin ligases, and Kelch-like protein 20 (KLHL20) is one of the most recent discoveries that have several biological roles which include its role in ubiquitin ligase activities. KLHL20 binds as a substrate component of ubiquitin ligase Cullin3 (Cul3). Several substrates for ubiquitin ligases (KLHL20 based) have been reported, these include Unc-51 Like Autophagy Activating Kinase 1 (ULK1), promyelocytic leukemia (PML), and Death Associated Protein Kinase 1 (DAPK1). KLHL20 shows multiple cell functions linked to several human diseases through ubiquitination of these substrates. Current literature shows that KLHL20 ubiquitin ligase regulates malignancies in humans and also suggests how important it is to develop regulating agents for tumour-suppressive KLHL20 to prevent tumourigenesis, Recent research has highlighted its potential therapeutic implications in several areas. In oncology, KLHL20's regulatory role in protein degradation pathways suggests that its targeting could offer novel strategies for cancer treatment by modulating the stability of proteins involved in tumour growth and survival. In neurodegenerative diseases, KLHL20's function in maintaining protein homeostasis positions it as a potential target for therapies aimed at managing protein aggregation and cellular stress. Here, we review the functions of KLHL20 during the carcinogenesis process, looking at its role in cancer progression, and regulation of ubiquitination events mediated by KLHL20 in human cancers, as well as its potential therapeutic interventions.

miR-181-5p/KLHL5 Promoted Proliferation and Migration of Gastric Cancer Through Activating METTL3-Mediated m6A Process

KLHL5 was a member of kelch-repeat protein family and was involved in the initiation of progression of a plethora of cancers. However, its specific role in gastric cancer was not explicitly illustrated. In this context, we aimed to investigate the biological role and mechanisms about KLHL5 in gastric cancer. qRT-PCR and western blot were used to investigate the expression of KLHL5 and EMT biomarkers. Wound healing assay, CCK-8, and Transwell assay were used to investigate the biological function of KLHL5. We found that KLHL5 was highly expressed in gastric cancer both in vivo and in vitro; besides, its high expression led to a shorter overall survival. Following statistical analysis showed that KLHL5 was associated with M stage. As for molecular experiments, we found that KLHL5 knockdown significantly reduced the proliferation, migration, and invasion ability of gastric cancer cell line MKN45 and SGC-7901. Furthermore, we found that miR-181-5p targeted KLHL5 to regulate m6A level through METTL3. In addition, KLHL5 knockdown could significantly reduce the lung metastasis rate in mice. In conclusion, we found that miR-181-5p/KLHL5 could promote the proliferation, migration, and invasion of gastric cancer by activating m6A process through regulating METTL3.

A novel gene signature to diagnose MASLD in metabolically unhealthy obese individuals

Visceral adipose tissue (VAT) contributes to metabolic dysfunction-associated steatotic liver disease (MASLD), releasing lipogenic substrates and cytokines which promote inflammation. Metabolic healthy obese individuals (MHO) may shift towardsunhealthy ones (MUHO) who develop MASLD, although the mechanisms are still unexplained. Therefore, we aimed to identify dysfunctional pathways and transcriptomic signatures shared by liver and VAT and to outline novel obesity-related biomarkers which feature MASLD in MUHO subjects, at higher risk of progressive liver disease and extrahepatic comorbidities. We performed RNA-sequencing in 167 hepatic samples and in a subset of 79 matched VAT, stratified in MHO and MUHO. A validation analysis was performed in hepatic samples and primary adipocytes from 12 bariatric patients, by qRT-PCR and western blot. We identified a transcriptomic signature that discriminate MUHO vs MHO, including 498 deregulated genes in liver and 189 in VAT. According to pathway and network analyses, oxidative phosphorylation resulted the only significantly downregulated pathway in both tissues in MUHO subjects. Next, we highlighted 5 genes commonly deregulated in liver and VAT, encompassing C6, IGF1, OXA1L, NDUFB11 and KLHL5 and we built a tissue-related score by integrating their expressions. Accordingly to RNAseq data, serum levels of C6 and IGF1, which are the only secreted proteins among those included in the gene signature were downregulated in MUHO vs MHO. Finally, the expression pattern of this 5-genes was confirmed in hepatic and VAT samples. We firstly identified the liver and VAT transcriptional phenotype of MUHO and a gene signature associated with the presence of MASLD in these at risk individuals.

Gene expression signature of human neuropathic pain identified through transcriptome analysis

Introduction: Neuropathic pain is a type of chronic pain that is characterized by ongoing discomfort and can be challenging to manage effectively. This study aimed to identify genes associated with neuropathic pain through transcriptome analysis in order to gain a better understanding of the mechanisms underlying this chronic, difficult-to-treat pain. Methods: We conducted transcriptome analysis using a training datasetof 202 individuals, including patients with neuropathic pain and healthy controls. Results: Our analysis identified five genes (GTF2H2, KLHL5, LRRC37A4P, PRR24, and MRPL23) that were significantly differentially expressed in the tissue of patients with neuropathic pain compared to controls. We constructed a neuropathic pain signature using these five genes and validated it using an independent dataset of 25 individuals. Receiver operating characteristic (ROC) curve analysis demonstrated that this signature had a high level of accuracy in differentiating between neuropathic pain patients and healthy controls, with an area under the curve (AUC) of 0.83 (95% CI 0.65-1). Discussion: These findings suggest that these five genes may be potential therapeutic targets for neuropathic pain.

KLHL5 Is a Prognostic-Related Biomarker and Correlated With Immune Infiltrates in Gastric Cancer

Background: KLHL5 (Kelch Like Family Member 5) is differentially expressed in gastric cancer, but its correlation with prognosis and functioning mechanism in gastric cancer remain unclear.

Methods: The Oncomine database and TIMER were employed to appraise the KLHL5 expression in a variety of cancers. The correlation between KLHL5 expression and patient prognosis was extracted from the Kaplan–Meier plotter, GEPIA, and PrognoScan database. Then the relationship between KLHL5 expression and inflammatory infiltrate profiles was inquired by TIMER. Finally, GEPIA and TIMER were explored for the correlative significance between KLHL5 expression and immune cell–related marker sets.

Results: KLHL5 was found to be differentially expressed and correlated with clinical outcomes in several types of cancers in the TCGA database. Especially, KLHL5 mRNA expression was upregulated and correlated with poorer overall survival and progression-free survival in gastric cancer. Moreover, elevated KLHL5 expression was significantly related with patient node stage, infiltration level, and expression of multiple immune marker sets.

Conclusions: These results implicate that KLHL5 expression is closely linked with patient clinical outcomes and the microenvironmental infiltration level in different neoplasms. This indicates that KLHL5 is a modulator in infiltrate recruitment, shaping the landscape of immune cell infiltration. Thus, it represents an eligible prognostic predictor for gastric malignancy.

Identification of Systems Level Molecular Signatures from Glioblastoma Multiforme Derived Extracellular Vesicles

Glioblastoma multiforme (GBM) is one of the most lethal malignancies of the central nervous system characterized by high mortality rate. The complexity of GBM pathogenesis, progression, and prognosis is not fully understood yet. GBM-derived extracellular vesicles (EVs) carry several oncogenic elements that facilitate GBM progression. The purpose of this study was to identify systems level molecular signatures from GBM-derived EVs using integrative analysis of publicly available transcriptomic data generated from plasma and serum samples. The dataset contained 19 samples in total, of which 15 samples were from plasma (11 GBM patients and 4 healthy samples) and 4 samples were from serum (2 GBM and 2 healthy samples). We carried out statistical analysis to identify differentially expressed genes (DEGs), functional enrichment analysis of the DEGs, protein-protein interaction networks, module analysis, transcription factors and target gene regulatory networks analysis, and identification of hub genes. The differential expression of the identified hub genes were validated with the independent TCGA-GBM dataset. We have identified a few crucial genes and pathways associated with GBM prognosis and therapy resistance. The DEGs identified from plasma were associated with inflammatory processes and viral infection. On the other hand, the hub genes identified from the serum samples were significantly associated with protein ubiquitinylation processes and cytokine signaling regulation. The findings indicate that GBM-derived plasma and serum DEGs may be associated with distinct cellular processes and pathways which facilitate GBM progression. The findings will provide better understanding of the molecular mechanisms of GBM pathogenesis and progression. These results can further be utilized for developing and validating minimally invasive diagnostic and therapeutic molecular biomarkers for GBM.

KLHL4, a novel p53 target gene, inhibits cell proliferation by activating p21WAF/CDKN1A

KLHL4 is a member of the KLHL protein family, many of whom bind the Cul3 E3 ligase, and mediate the ubiquitination of interacting proteins. The KLHL4 gene, localized on the X chromosome, associates with a disorder known as X-linked cleft palate (CPX). However, the biological functions of KLHL4 are largely unknown. In this study, microarray analysis of HEK293A embryonic kidney cells, expressing ectopic p53, showed a 3-fold increase of KLHL4 mRNA. Moreover, both KLHL4 mRNA and protein expression were elevated by p53 or DNA damage, suggesting that KLHL4 might be a p53 target gene. We also found that KLHL4 activates transcription of p21^WAF/CDKN1A, a p53 target gene encoding a major negative regulator of the cell-cycle. KLHL4 interacted with p53 to increase its binding to p53 response element of the p21^WAF/CDKN1A gene, resulting in transcriptional upregulation. Furthermore, we observed that KLHL4 can interact with the Cul3 ubiquitin ligase, to possibly play a role in ubiquitin-mediated proteasomal degradation, and Klhl4 knocked-out MEF mouse embryonic fibroblasts proliferated faster than WT MEF cells. These results suggest that KLHL4 upregulation by p53 may inhibit cell proliferation, by activating p21^WAF/CDKN1A.

Druggable Sphingolipid Pathways: Experimental Models and Clinical Opportunities

Intensive research in the field of sphingolipids has revealed diverse roles in cell biological responses and human health and disease. This immense molecular family is primarily represented by the bioactive molecules ceramide, sphingosine, and sphingosine 1-phosphate (S1P). The flux of sphingolipid metabolism at both the subcellular and extracellular levels provides multiple opportunities for pharmacological intervention. The caveat is that perturbation of any single node of this highly regulated flux may have effects that propagate throughout the metabolic network in a dramatic and sometimes unexpected manner. Beginning with S1P, the receptors for which have thus far been the most clinically tractable pharmacological targets, this review will describe recent advances in therapeutic modulators targeting sphingolipids, their chaperones, transporters, and metabolic enzymes.

Kelch-like protein 5-mediated ubiquitination of lysine 183 promotes proteasomal degradation of sphingosine kinase 1

Sphingosine kinase 1 (SK1) is a signalling enzyme that catalyses the phosphorylation of sphingosine to generate the bioactive lipid sphingosine 1-phosphate (S1P). A number of SK1 inhibitors and chemotherapeutics can induce the degradation of SK1, with the loss of this pro-survival enzyme shown to significantly contribute to the anti-cancer properties of these agents. Here we define the mechanistic basis for this degradation of SK1 in response to SK1 inhibitors, chemotherapeutics, and in natural protein turnover. Using an inducible SK1 expression system that enables the degradation of pre-formed SK1 to be assessed independent of transcriptional or translational effects, we found that SK1 was degraded primarily by the proteasome since several proteasome inhibitors blocked SK1 degradation, while lysosome, cathepsin B or pan caspase inhibitors had no effect. Importantly, we demonstrate that this proteasomal degradation of SK1 was enabled by its ubiquitination at Lys183 that appears facilitated by SK1 inhibitor-induced conformational changes in the structure of SK1 around this residue. Furthermore, using yeast two-hybrid screening, we identified Kelch-like protein 5 (KLHL5) as an important protein adaptor linking SK1 to the cullin 3 (Cul3) ubiquitin ligase complex. Notably, knockdown of KLHL5 or Cul3, use of a cullin inhibitor or a dominant-negative Cul3 all attenuated SK1 degradation. Collectively this data demonstrates the KLHL5/Cul3-based E3 ubiquitin ligase complex is important for regulation of SK1 protein stability via Lys183 ubiquitination, in response to SK1 inhibitors, chemotherapy and for normal SK1 protein turnover.

Cullin-Ring ubiquitin ligases in kidney health and disease

PURPOSE OF REVIEW

Members of the Cullin family act as scaffolds in E3 ubiquitin ligases and play a central role in mediating protein degradation. Interactions with many different substrate-binding adaptors permit Cullin-containing E3 ligases to participate in diverse cellular functions. In the kidney, one well established target of Cullin-mediated degradation is the transcription factor Nrf2, a key player in responses to oxidative stress. The goal of this review is to discuss more recent findings revealing broader roles for Cullins in the kidney.

RECENT FINDINGS

Cullin 3 acts as the scaffold in the E3 ligase regulating Nrf2 abundance, but was more recently shown to be mutated in the disease familial hyperkalemic hypertension. Studies seeking to elucidate the molecular mechanisms by which Cullin 3 mutations lead to dysregulation of renal sodium transport will be discussed. Disruption of Cullin 3 in mice unexpectedly causes polyuria and fibrotic injury suggesting it has additional roles in the kidney. We will also review recent transcriptomic data suggesting that other Cullins are also likely to play important roles in renal function.

SUMMARY

Cullins form a large and diverse family of E3 ubiquitin ligases that are likely to have many important functions in the kidney.