Revisiting CFTR Interactions: Old Partners and New Players

Cystic Fibrosis and Cancer: Unraveling the Complex Role of CFTR Gene in Cancer Susceptibility

Cystic fibrosis (CF) is a genetic disorder affecting multiple organs, primarily the lungs and digestive system. Over the years, advancements in medical care and treatments have significantly increased the life expectancy of individuals with CF. However, with this improved longevity, concerns about the potential risk of developing certain types of cancers have arisen. This narrative review aims to explore the relationship between CF, increased life expectancy, and the associated risk for cancers. We discuss the potential mechanisms underlying this risk, including chronic inflammation, immune system dysregulation, and genetic factors. Additionally, we review studies that have examined the incidence and types of cancers seen in CF patients, with a focus on gastrointestinal, breast, and respiratory malignancies. We also explore the impact of CFTR modulator therapies on cancer risk. In the gastrointestinal tract, CF patients have an elevated risk of developing colorectal cancer, pancreatic cancer, and possibly esophageal cancer. The underlying mechanisms contributing to these increased risks are not fully understood, but chronic inflammation, altered gut microbiota, and genetic factors are believed to play a role. Regular surveillance and colonoscopies are recommended for early detection and management of colorectal cancer in CF patients. Understanding the factors contributing to cancer development in CF patients is crucial for implementing appropriate surveillance strategies and improving long-term outcomes. Further research is needed to elucidate the molecular mechanisms involved and develop targeted interventions to mitigate cancer risk in individuals with CF.

A Proteomic Survey of the Cystic Fibrosis Transmembrane Conductance Regulator Surfaceome

The aim of this review article is to collate recent contributions of proteomic studies to cystic fibrosis transmembrane conductance regulator (CFTR) biology. We summarize advances from these studies and create an accessible resource for future CFTR proteomic efforts. We focus our attention on the CFTR interaction network at the cell surface, thus generating a CFTR 'surfaceome'. We review the main findings about CFTR interactions and highlight several functional categories amongst these that could lead to the discovery of potential biomarkers and drug targets for CF.

It Takes Two to Tango! Protein-Protein Interactions behind cAMP-Mediated CFTR Regulation

Over the last fifteen years, with the approval of the first molecular treatments, a breakthrough era has begun for patients with cystic fibrosis (CF), the rare genetic disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). These molecules, known as CFTR modulators, have led to unprecedented improvements in the lung function and quality of life of most CF patients. However, the efficacy of these drugs is still suboptimal, and the clinical response is highly variable even among individuals bearing the same mutation. Furthermore, not all patients carrying rare CFTR mutations are eligible for CFTR modulator therapies, indicating the need for alternative and/or add-on therapeutic approaches. Because the second messenger 3',5'-cyclic adenosine monophosphate (cAMP) represents the primary trigger for CFTR activation and a major regulator of different steps of the life cycle of the channel, there is growing interest in devising ways to fine-tune the cAMP signaling pathway for therapeutic purposes. This review article summarizes current knowledge regarding the role of cAMP signalosomes, i.e., multiprotein complexes bringing together key enzymes of the cAMP pathway, in the regulation of CFTR function, and discusses how modulating this signaling cascade could be leveraged for therapeutic intervention in CF.

YES1 Kinase Mediates the Membrane Removal of Rescued F508del-CFTR in Airway Cells by Promoting MAPK Pathway Activation via SHC1

Recent developments in CFTR modulator drugs have had a significant transformational effect on the treatment of individuals with Cystic Fibrosis (CF) who carry the most frequent F508del-CFTR mutation in at least one allele. However, the clinical effects of these revolutionary drugs remain limited by their inability to fully restore the plasma membrane (PM) stability of the rescued mutant channels. Here, we shed new light on the molecular mechanisms behind the reduced half-life of rescued F508del-CFTR at the PM of airway cells. We describe that YES1 protein kinase is enriched in F508del-CFTR protein PM complexes, and that its interaction with rescued channels is mediated and dependent on the adaptor protein YAP1. Moreover, we show that interference with this complex, either by depletion of one of these components or inhibiting YES1 activity, is sufficient to significantly improve the abundance and stability of modulator-rescued F508del-CFTR at the surface of airway cells. In addition, we found that this effect was mediated by a decreased phosphorylation of the scaffold protein SHC1, a key regulator of MAPK pathway activity. In fact, we showed that depletion of SHC1 or inhibition of MAPK pathway signaling was sufficient to improve rescued F508del-CFTR surface levels, whereas an ectopic increase in pathway activation downstream of SHC1, through the use of a constitutively active H-RAS protein, abrogated the stabilizing effect of YES1 inhibition on rescued F508del-CFTR. Taken together, our findings not only provide new mechanistic insights into the regulation of modulator-rescued F508del-CFTR membrane stability, but also open exciting new avenues to be further explored in CF research and treatment.

Development and validation of a prognosis prediction model based on 18 endoplasmic reticulum stress-related genes for patients with lung adenocarcinoma

Background

Endoplasmic reticulum (ER) stress had a crucial impact on cell survival, proliferation, and metastasis in various cancers. However, the role of ER stress in lung adenocarcinoma remains unclear.

Method

Gene expression and clinical data of lung adenocarcinoma (LUAD) samples were extracted from The Cancer Genome Atlas (TCGA) and three Gene Expression Omnibus (GEO) datasets. ER stress score (ERSS) was constructed based on hub genes selected from 799 ER stress-related genes by least absolute shrinkage and selection operator (LASSO) regression. A Cox regression model, integrating ERSS and the TNM stage, was developed to predict overall survival (OS) in TCGA cohort and was validated in GEO cohorts. Gene set enrichment analysis (GSEA), single-sample GSEA (ssGSEA), and gene mutation analyses were performed to further understand the molecular features of ERSS. The tumor immune infiltration was evaluated by ESTIMATE, CIBERSORT, and xCell algorithms. The receiver operating characteristic (ROC) curves were used to evaluate the predictive value of the risk model. p< 0.05 was considered statistically significant.

Results

One hundred fifty-seven differentially expressed genes (DEGs) were identified between tumor and para-carcinoma tissues, and 45 of them significantly correlated with OS. Next, we identified 18 hub genes and constructed ERSS by LASSO regression. Multivariate analysis demonstrated that higher ERSS (p< 0.0001, hazard ratio (HR) = 3.8, 95%CI: 2.8–5.2) and TNM stage (p< 0.0001, HR = 1.55, 95%CI: 1.34–1.8) were independent predictors for worse OS. The prediction model integrating ERSS and TNM stage performed well in TCGA cohort (area under the curve (AUC) at five years = 0.748) and three GEO cohorts (AUC at 5 years = 0.658, 0.717, and 0.739). Pathway enrichment analysis showed that ERSS significantly correlated with unfolded protein response. Meanwhile, pathways associated with the cell cycle, growth, and metabolism were significantly enriched in the high ERSS group. Patients with SMARCA4, TP53, and EGFR mutations showed significantly higher ERSS (p = 4e−04, 0.0027, and 0.035, respectively). Tissues with high ERSS exhibited significantly higher infiltration of M1 macrophages, activated dendritic cells, and lower infiltration of CD8+ T cells and B cells, which indicate an activated tumor antigen-presenting but suppressive immune response status.

Conclusion

We developed and validated an ER stress-related risk model that exhibited great predictive value for OS in patients with LUAD. Our work also expanded the understanding of the role of ER stress in LUAD.

Differential CFTR-Interactome Proximity Labeling Procedures Identify Enrichment in Multiple SLC Transporters

Proteins interacting with CFTR and its mutants have been intensively studied using different experimental approaches. These studies provided information on the cellular processes leading to proper protein folding, routing to the plasma membrane, recycling, activation and degradation. Recently, new approaches have been developed based on the proximity labeling of protein partners or proteins in close vicinity and their subsequent identification by mass spectrometry. In this study, we evaluated TurboID- and APEX2-based proximity labeling of WT CFTR and compared the obtained data to those reported in databases. The CFTR-WT interactome was then compared to that of two CFTR (G551D and W1282X) mutants and the structurally unrelated potassium channel KCNK3. The two proximity labeling approaches identified both known and additional CFTR protein partners, including multiple SLC transporters. Proximity labeling approaches provided a more comprehensive picture of the CFTR interactome and improved our knowledge of the CFTR environment.

A novel role for CFTR interaction with LH and FGF in azoospermia and epididymal maldevelopment caused by cryptorchidism

Cryptorchidism occurs frequently in children with cystic fibrosis. Among boys with cryptorchidism and abrogated mini-puberty, the development of the epididymis and the vas deferens is frequently impaired. This finding suggests that a common cause underlies the abnormal development of Ad spermatogonia and the epididymis. The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette transporter protein that acts as a chloride channel. The CFTR gene has been associated with spermatogenesis and male fertility. In boys with cryptorchidism, prepubertal hypogonadotropic hypogonadism induces suboptimal expression of the ankyrin-like protein gene, ASZ1, the P-element induced wimpy testis-like gene, PIWIL, and CFTR. The abrogated expression of these gene leads to transposon reactivation, and ultimately, infertility. Curative gonadotropin-releasing hormone agonist (GnRHa) treatment stimulates the expression of CFTR and PIWIL3, which play important roles in the development of Ad spermatogonia and fertility. Furthermore, GnRHa stimulates the expression of the epididymal androgen-sensitive genes, CRISP1, WFDC8, SPINK13, and PAX2, which thereby promotes epididymal development. This review focuses on molecular evidence that favors a role for CFTR in cryptorchidism-induced infertility. Based on information available in the literature, we interpreted our RNA-Seq expression data obtained from samples before and after randomized GnRHa treatment in boys with bilateral cryptorchidism. We propose that, in boys with cryptorchidism, CFTR expression is controlled by luteinizing hormone and testosterone. Moreover, CFTR regulates the activities of genes that are important for fertility and Wolffian duct differentiation.