CFTR suppresses tumor progression through miR-193b targeting urokinase plasminogen activator (uPA) in prostate cancer

The ageing of people living with cystic fibrosis: what to expect now?

The prognosis of people with cystic fibrosis (pwCF) has improved dramatically with the introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators (CFTRm). The ageing of the cystic fibrosis (CF) population is changing the disease landscape with the emergence of different needs and increasing comorbidities related to both age and long-term exposure to multiple treatments including CFTRm. Although the number of pwCF eligible for this treatment is expected to increase, major disparities in care and outcomes still exist in this population. Moreover, the long-term impact of the use of CFTRm is still partly unknown due to the current short follow-up and experience with their use, thus generating some uncertainties. The future spread and initiation of these drugs at an earlier stage of the disease is expected to reduce the systemic burden of systemic inflammation and its consequences on health. However, the prolonged life expectancy is accompanied by an increasing burden of age-related comorbidities, especially in the context of chronic disease. The clinical manifestations of the comorbidities directly or indirectly associated with CFTR dysfunction are changing, along with the disease dynamics and outcomes. Current protocols used to monitor slow disease progression will need continuous updates, including the composition of the multidisciplinary team for CF care, with a greater focus on the needs of the adult population.

Linking ABC transporters to the hallmarks of cancer

Human ATP-binding cassette (ABC) transporters are ubiquitously expressed and transport a broad range of endogenous and xenobiotic substrates across extra- and intracellular membranes. Mutations in ABC genes cause 21 monogenic diseases, and polymorphisms in these genes are associated with susceptibility to complex diseases. ABC transporters also play a major role in drug bioavailability, and they mediate multidrug resistance in cancer. At least 13 ABC transporters were shown to be involved in drug resistance in vitro. In the past decade, efforts have been made to elucidate their roles in tumor biology. Herein, we explore their involvement in tumorigenesis, focusing on the hallmarks of cells as they make their way from normalcy to neoplastic growth states.

Androgen-induced upregulation of CFTR in pancreatic β-cell contributes to hyperinsulinemia in PCOS model

PURPOSE

Polycystic ovarian syndrome (PCOS) is an endocrine-metabolic condition affecting 5-10% of reproductive-aged women and characterized by hyperandrogenism, insulin resistance (IR), and hyperinsulinemia. CFTR is known to be regulated by steroid hormones, and our previous study has demonstrated an essential role of CFTR in β-cell function. This study aims to investigate the contribution of androgen and CFTR to hypersecretion of insulin in PCOS and the underlying mechanism.

METHODS

We established a rat PCOS model by subcutaneously implanting silicon tubing containing Dihydrotestosterone (DHT). Glucose tolerance test with insulin levels was performed at 9 weeks after implantation. A rat β-cell line RINm5F, a mouse β-cell line β-TC-6, and mouse islets were treated with DHT, and with or without the androgen antagonist flutamide for CFTR and insulin secretion-related functional assays or mRNA/protein expression measurement. The effect of CFTR inhibitors on DHT-promoted membrane depolarization, glucose-stimulated intracellular Ca2+ oscillation and insulin secretion were examined by membrane potential imaging, calcium imaging and ELISA, respectively.

RESULTS

The DHT-induced PCOS model showed increased body weight, impaired glucose tolerance, and higher blood glucose and insulin levels after glucose stimulation. CFTR was upregulated in islets of PCOS model and DHT-treated cells, which was reversed by flutamide. The androgen receptor (AR) could bind to the CFTR promoter region, which was enhanced by DHT. Furthermore, DHT-induced membrane depolarization, enhanced glucose-stimulated Ca2+ oscillations and insulin secretion, which could be abolished by CFTR inhibitors.

CONCLUSIONS

Excessive androgen enhances glucose-stimulating insulin secretion through upregulation of CFTR, which may contribute to hyperinsulinemia in PCOS.

Posttranscriptional Regulation of the Plasminogen Activation System by Non-Coding RNA in Cancer

Various species of non-coding RNAs (ncRNAs) may act as functional molecules regulating diverse biological processes. In cancer cell biology, ncRNAs include RNAs that regulate the expression of oncogenes and tumor suppressor genes through various mechanisms. The urokinase (uPA)-mediated plasminogen activation system (PAS) includes uPA, its inhibitors PAI-1 and PAI-2 and its specific cellular receptor uPAR; their increased expression represents a negative prognostic factor in several cancers. Here, we will briefly describe the main uPA-mediated PAS components and ncRNA species; then, we will review more recent evidence of the roles that ncRNAs may play in regulating the expression and functions of uPA-mediated PAS components in cancer.

CFTR and Gastrointestinal Cancers: An Update

Cystic Fibrosis (CF) is a disease caused by mutations in the CFTR gene that severely affects the lungs as well as extra-pulmonary tissues, including the gastrointestinal (GI) tract. CFTR dysfunction resulting from either mutations or the downregulation of its expression has been shown to promote carcinogenesis. An example is the enhanced risk for several types of cancer in patients with CF, especially cancers of the GI tract. CFTR also acts as a tumor suppressor in diverse sporadic epithelial cancers in many tissues, primarily due to the silencing of CFTR expression via multiple mechanisms, but especially due to epigenetic regulation. This review provides an update on the latest research linking CFTR-deficiency to GI cancers, in both CF patients and in sporadic GI cancers, with a particular focus on cancer of the intestinal tract. It will discuss changes in the tissue landscape linked to CFTR-deficiency that may promote cancer development such as breakdowns in physical barriers, microbial dysbiosis and inflammation. It will also discuss molecular pathways and mechanisms that act upstream to modulate CFTR expression, such as by epigenetic silencing, as well as molecular pathways that act downstream of CFTR-deficiency, such as the dysregulation of the Wnt/β-catenin and NF-κB signaling pathways. Finally, it will discuss the emerging CFTR modulator drugs that have shown promising results in improving CFTR function in CF patients. The potential impact of these modulator drugs on the treatment and prevention of GI cancers can provide a new example of personalized cancer medicine.

Cystic fibrosis transmembrane conductance regulator (CFTR): beyond cystic fibrosis

Background

The cystic fibrosis transmembrane conductance regulator (CFTR) gene has been traditionally linked to cystic fibrosis (CF) inheritance in an autosomal recessive manner. Advances in molecular biology and genetics have expanded our understanding of the CFTR gene and its encoding products expressed in different tissues.

Aim

The study’s aim consists of reviewing the different pathological CF phenotypes using the existing literature. We know that alterations of the CFTR protein’s structure may result in different pathological phenotypes.

Methods

Open sources such as PubMed and Science Direct databases have been used for this review. We focused our selection on articles published within the last 15 years. Critical terms related to the CFTR protein have been used: “CFTR AND cancer,” “CFTR AND celiac disease,” “CFTR AND pancreatitis,” “children,” “adults,” “genotype,” “phenotype,” “correlation,” “mutation,”  “CFTR,” “diseases,” “disorders,” and “no cystic fibrosis.”

Results

We analyzed 1,115 abstracts in total. Moreover, only 189 were suitable for the topic. We focused on the role of CFTR in cancer, gastrointestinal disorders, respiratory diseases, reproductive system, and systemic hypertension.

Conclusions

Mutations in CFTR gene are often associated with CF. In this review, we highlighted the broad spectrum of alterations reported for this gene, which may be involved in the pathogenesis of other diseases. The importance of these new insights in the role of CFTR relies on the possibility of considering this protein/gene as a novel therapeutic target for CF- and CFTR-related diseases.

Exploring YAP1-centered networks linking dysfunctional CFTR to epithelial-mesenchymal transition

In this work, a systems biology approach identifies potentially dysregulated EMT signaling in CF (including the Hippo, Wnt, TGF-β, p53, and MYC pathways), integrated by YAP1 and TEAD4.

Mutations in the CFTR anion channel cause cystic fibrosis (CF) and have also been related to higher cancer incidence. Previously we proposed that this is linked to an emerging role of functional CFTR in protecting against epithelial–mesenchymal transition (EMT). However, the pathways bridging dysfunctional CFTR to EMT remain elusive. Here, we applied systems biology to address this question. Our data show that YAP1 is aberrantly active in the presence of mutant CFTR, interacting with F508del, but not with wt-CFTR, and that YAP1 knockdown rescues F508del-CFTR processing and function. Subsequent analysis of YAP1 interactors and roles in cells expressing either wt- or F508del-CFTR reveal that YAP1 is an important mediator of the fibrotic/EMT processes in CF. Alongside, five main pathways emerge here as key in linking mutant CFTR to EMT, namely, (1) the Hippo pathway; (2) the Wnt pathway; (3) the TGFβ pathway; (4) the p53 pathway; and (5) MYC signaling. Several potential hub proteins which mediate the crosstalk among these pathways were also identified, appearing as potential therapeutic targets for both CF and cancer.

Proteomic profiling reveals antitumor effects of RT2 peptide on a human colon carcinoma xenograft mouse model

A comparative study of human colon HCT-116 xenograft in nude mice treated with and without peptide RT2 at high doses is performed along with a label-free proteomic analysis of the tissue in order to understand the potential mechanisms by which RT2 acts in vivo against colorectal tumors. RT2 displays no significant systematic toxicity, but reduces tumor growth after either intraperitoneal or intratumoral injection demonstrating it is a safe and efficacious antitumor agent in vivo. Of the 3196 proteins identified by label-free proteomics, 61 proteins appear only in response to RT2 and are involved in cellular processes largely localized in the cells and cell parts. Some of the proteins identified, including CFTR, Wnt7a, TIA1, PADI2, NRBP2, GADL1, LZIC, TLR6, and GPR37, have been reported to suppress tumor growth and are associated with cell proliferation, invasion, metastasis, angiogenesis, apoptosis, and immune evasion. Our work supports their role as tumor biomarkers and reveals RT2 has a complex mechanism of action in vivo.

Chloride Channels and Transporters: Roles beyond Classical Cellular Homeostatic pH or Ion Balance in Cancers

Simple Summary

Roles of chloride-associated transporters have been raised in various cancers. Although complicated ion movements, crosstalk among channels/transporters through homeostatic electric regulation, difficulties with experimental implementation such as activity measurement of intracellular location were disturbed to verify the precise modulation of channels/transporters, recently defined cancerous function and communication with tumor microenvironment of chloride channels/transporters should be highlighted beyond classical homeostatic ion balance. Chloride-associated transporters as membrane-associated components of chloride movement, regulations of transmembrane member 16A, calcium-activated chloride channel regulators, transmembrane member 206, chloride intracellular channels, voltage-gated chloride channels, cystic fibrosis transmembrane conductance regulator, voltage-dependent anion channel, volume-regulated anion channel, and chloride-bicarbonate exchangers are discussed.

Abstract

The canonical roles of chloride channels and chloride-associated transporters have been physiologically determined; these roles include the maintenance of membrane potential, pH balance, and volume regulation and subsequent cellular functions such as autophagy and cellular proliferative processes. However, chloride channels/transporters also play other roles, beyond these classical function, in cancerous tissues and under specific conditions. Here, we focused on the chloride channel-associated cancers and present recent advances in understanding the environments of various types of cancer caused by the participation of many chloride channel or transporters families and discuss the challenges and potential targets for cancer treatment. The modulation of chloride channels/transporters might promote new aspect of cancer treatment strategies.

Cancer in Cystic Fibrosis: A Narrative Review of Prevalence, Risk Factors, Screening, and Treatment Challenges: Adult Cystic Fibrosis Series

Cystic fibrosis (CF) is a progressive monogenetic disorder that causes persistent pulmonary disease, but also affects other organ systems, including the digestive tract. Recent advances in treatment and care of patients with CF, including the use of new and highly effective CF transmembrane conductance regulator modulators, have led to a dramatic increase in survival. Young patients with CF now can expect to live to or beyond middle age, when cancer is more frequent. Patients with CF now are known to face an increased risk of digestive tract cancer, particularly cancer of the colon. The risk, which could be triggered by associated CF-related conditions or other genetic mechanisms, is even greater in patients who received a transplant. Also some evidence suggests that adenomatous polyps develop more frequently in patients with CF and at an earlier age than in patients without CF. To reduce the excess risk of intestinal cancer in patients with CF, the Cystic Fibrosis Foundation has developed colonoscopy-based guidelines. For nontransplanted patients, colonoscopy should begin at 40 years of age, with rescreening at 5-year intervals; the screening interval should be shortened to 3 years if adenomatous polyps are discovered. For transplanted patients, screening should start at 30 years of age, or within 2 years of the transplant operation. Before colonoscopy, it is essential for patients with CF to undergo a special, more intensive bowel preparation than normally used for those without CF. Whether the new drugs that have dramatically improved morbidity and mortality for patients with CF will alter the risk of cancer is unknown and needs to be assessed in future studies.

Inferred inactivation of the Cftr gene in the duodena of mice exposed to hexavalent chromium (Cr(VI)) in drinking water supports its tumor-suppressor status and implies its potential role in Cr(VI)-induced carcinogenesis of the small intestines

Carcinogenicity of hexavalent chromium [Cr (VI)] has been supported by a number of epidemiological and animal studies; however, its carcinogenic mode of action is still incompletely understood. To identify mechanisms involved in cancer development, we analyzed gene expression data from duodena of mice exposed to Cr(VI) in drinking water. This analysis included (i) identification of upstream regulatory molecules that are likely responsible for the observed gene expression changes, (ii) identification of annotated gene expression data from public repositories that correlate with gene expression changes in duodena of Cr(VI)-exposed mice, and (iii) identification of hallmark and oncogenic signature gene sets relevant to these data. We identified the inactivated CFTR gene among the top scoring upstream regulators, and found positive correlations between the expression data from duodena of Cr(VI)-exposed mice and other datasets in public repositories associated with the inactivation of the CFTR gene. In addition, we found enrichment of signatures for oncogenic signaling, sustained cell proliferation, impaired apoptosis and tissue remodeling. Results of our computational study support the tumor-suppressor role of the CFTR gene. Furthermore, our results support human relevance of the Cr(VI)-mediated carcinogenesis observed in the small intestines of exposed mice and suggest possible groups that may be more vulnerable to the adverse outcomes associated with the inactivation of CFTR by hexavalent chromium or other agents. Lastly, our findings predict, for the first time, the role of CFTR inactivation in chemical carcinogenesis and expand the range of plausible mechanisms that may be operative in Cr(VI)-mediated carcinogenesis of intestinal and possibly other tissues.

miR-125b Promotes Colorectal Cancer Migration and Invasion by Dual-Targeting CFTR and CGN

Simple Summary

Colorectal cancer (CRC) is the third leading cause for cancer related death, in which metastasis exerts a pivotal role. Therefore, we aim to find out the possible mechanism underlying CRC metastasis. We found that the level of miR-125b was elevated in normal, primary CRC, and distant metastasis tissues stepwise, and high level miR-125b was positively correlated with lymph node metastasis and tumor differentiation. In vitro and in vivo assays showed miR-125b significantly promoted CRC migration and invasion. To elucidate the potential mechanism, cystic fibrosis transmembrane conductance regulator (CFTR) and cingulin (CGN) were defined as two target genes of miR-125b. On the one hand, miR-125b promoted epithelial-mesenchymal transition (EMT) and the production and secretion of urokinase plasminogen activator (uPA) by inhibiting CFTR; on the other hand, miR-125b activated Ras Homolog Family Member A (RhoA)/Rho Kinase (ROCK) signaling by repressing CGN. Therefore, we provided a potential biomarker for CRC prevention and treatment in the future.

Abstract

Metastasis contributes to the poor prognosis of colorectal cancer, the causative factor of which is not fully understood. Previously, we found that miR-125b (Accession number: MIMAT0000423) contributed to cetuximab resistance in colorectal cancer (CRC). In this study, we identified a novel mechanism by which miR-125b enhances metastasis by targeting cystic fibrosis transmembrane conductance regulator (CFTR) and the tight junction-associated adaptor cingulin (CGN) in CRC. We found that miR-125b expression was upregulated in primary CRC tumors and metastatic sites compared with adjacent normal tissues. Overexpression of miR-125b in CRC cells enhanced migration capacity, while knockdown of miR-125b decreased migration and invasion. RNA-sequencing (RNA-seq) and dual-luciferase reporter assays identified CFTR and CGN as the target genes of miR-125b, and the inhibitory impact of CFTR and CGN on metastasis was further verified both in vitro and in vivo. Moreover, we found that miR-125b facilitated the epithelial-mesenchymal transition (EMT) process and the expression and secretion of urokinase plasminogen activator (uPA) by targeting CFTR and enhanced the Ras Homolog Family Member A (RhoA)/Rho Kinase (ROCK) pathway activity by targeting CGN. Together, these findings suggest miR-125b as a key functional molecule in CRC and a promising biomarker for the diagnosis and treatment of CRC.

Genome-wide analysis of methylation CpG sites in gene promoters identified four pairs of CpGs-mRNAs associated with lung adenocarcinoma prognosis

BACKGROUND

Activation of oncogenes through promoter hypomethylation and silencing of tumor suppressor genes induced by promoter hypermethylation played essential roles in the progression of lung adenocarcinoma (LUAD). This study aimed to identify the LUAD prognostic CpG sites and the regulated genes which contributed to LUAD progression.

METHODS

Methylation profiles from TCGA and GSE60645 were used to screen the differentially methylated CpGs. Then, the Log-rank test was adopted to identify LUAD prognosis-associated CpGs. Differential gene expression and survival analyses were further performed to suggest the roles of methylation-driven genes in LUAD prognosis. Finally, models and nomograms were constructed to predict the prognosis of LUAD.

RESULTS

A total of 1891 CpGs at gene promoters were differentially methylated. Among them, 54 CpGs were significantly associated with LUAD prognosis. Nine of them showed significant correlations with the expression of four genes (CCDC181, CFTR, PPP1R16B, MYEOV). CCDC181, CFTR and PPP1R16B were aberrantly down-regulated in LUAD, while MYEOV was up-regulated. All of them were significantly associated with LUAD prognosis. The LASSO regression analysis indicated that tumor stages, cg09181792, cg16998150, cg22779330 and PPP1R16B were promising prognostic factors. The AUC (area under the curve) of the model containing the clinical predictors was 0.643. The combination of CpGs and PPP1R16B with clinical variables significantly improved the predictive efficiency with an AUC of 0.714 (P = 0.036).

CONCLUSION

This study identified four pairs of promoter CpGs and genes that were significantly associated with LUAD prognosis. The integration of CpGs methylation and gene expression showed better predictive ability for LUAD prognosis.

DNA Methylation-Mediated Low Expression of CFTR Stimulates the Progression of Lung Adenocarcinoma

In recent years, the mortality rate of lung adenocarcinoma (LUAD) is persistently increasing, which has already caused a huge impact on human living standards. Hence, there is an urgent need to probe the molecular mechanism of LUAD progression, so as to disclose prognostic and diagnostic markers for patients with LUAD. Methylation 450 K data and mRNA expression data of LUAD were obtained via bioinformatics analysis to screen methylation-driven genes. The expression of the target gene was detected through qRT-PCR, while the methylation level was evaluated via methylation-specific PCR (MSP). The impact of the gene on cell proliferation, migration, invasion, apoptosis and cell cycle was measured through CCK-8, wound healing, Transwell invasion assay, and flow cytometry. CFTR was defined by bioinformatics analysis as the target gene for this study. qRT-PCR revealed that CFTR was lowly expressed in LUAD cells. MSP displayed that the CFTR promoter region in LUAD cells was hypermethylated, and demethylation could pronouncedly increase the level of CFTR mRNA in LUAD cells. Cell biological functional experiments exhibited that CFTR hindered cell proliferation, migration, and invasion, fostered cell apoptosis of LUAD, and blocked the cell cycle in G2-M phase. CFTR was hypermethylated in LUAD, which mediated the low expression of CFTR in LUAD to stimulate the progression of LUAD.

Bioelectrical approaches to cancer as a problem of the scaling of the cellular self

One lens with which to understand the complex phenomenon of cancer is that of developmental biology. Cancer is the inevitable consequence of a breakdown of the communication that enables individual cells to join into computational networks that work towards large-scale, morphogenetic goals instead of more primitive, unicellular objectives. This perspective suggests that cancer may be a physiological disorder, not necessarily due to problems with the genetically-specified protein hardware. One aspect of morphogenetic coordination is bioelectric signaling, and indeed an abnormal bioelectric signature non-invasively reveals the site of incipient tumors in amphibian models. Functionally, a disruption of resting potential states triggers metastatic melanoma phenotypes in embryos with no genetic defects or carcinogen exposure. Conversely, optogenetic or molecular-biological modulation of bioelectric states can override powerful oncogenic mutations and prevent or normalize tumors. The bioelectrically-mediated information flows that harness cells toward body-level anatomical outcomes represent a very attractive and tractable endogenous control system, which is being targeted by emerging approaches to cancer.

CFTR chloride channel activity modulates the mitochondrial morphology in cultured epithelial cells

The impairment of the CFTR channel activity, a cAMP-activated chloride (Cl^-) channel responsible for cystic fibrosis (CF), has been associated with a variety of mitochondrial alterations such as modified gene expression, impairment in oxidative phosphorylation, increased reactive oxygen species (ROS), and a disbalance in calcium homeostasis. The mechanisms by which these processes occur in CF are not fully understood. Previously, we demonstrated a reduced MTND4 expression and a failure in the mitochondrial complex I (mCx-I) activity in CF cells. Here we hypothesized that the activity of CFTR might modulate the mitochondrial fission/fusion balance, explaining the decreased mCx-I. The mitochondrial morphology and the levels of mitochondrial dynamic proteins MFN1 and DRP1 were analysed in IB3-1 CF cells, and S9 (IB3-1 expressing wt-CFTR), and C38 (IB3-1 expressing a truncated functional CFTR) cells. The mitochondrial morphology of IB3-1 cells compared to S9 and C38 cells showed that the impaired CFTR activity induced a fragmented mitochondrial network with increased rounded mitochondria and shorter branches. Similar results were obtained by using the CFTR pharmacological inhibitors CFTR(inh)-172 and GlyH101 on C38 cells. These morphological changes were accompanied by modifications in the levels of the mitochondrial dynamic proteins MFN1, DRP1, and p(616)-DRP1. IB3-1 CF cells treated with Mdivi-1, an inhibitor of mitochondrial fission, restored the mCx-I activity to values similar to those seen in S9 and C38 cells. These results suggest that the mitochondrial fission/fusion balance is regulated by the CFTR activity and might be a potential target to treat the impaired mCx-I activity in CF.

Expression and Role of CFTR in Human Esophageal Squamous Cell Carcinoma

BACKGROUND

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-dependent chloride (Cl^-) anion conducting channel, and its role in esophageal squamous cell carcinoma (ESCC) was examined in the present study.

METHODS

Overexpression experiments were conducted on human ESCC cell lines following the transfection of a CFTR plasmid, and changes in cell proliferation, the cell cycle, apoptosis, migration, and invasion were assessed. A microarray analysis was performed to examine gene expression profiles. Fifty-three primary tumor samples collected from ESCC patients during esophagectomy were subjected to an immunohistochemical analysis.

RESULTS

Transfection of the CFTR plasmid into the ESCC KYSE 170 and KYSE 70 cell lines suppressed cell proliferation, migration, and invasion and induced apoptosis. The microarray analysis showed the up-regulated expression of genes involved in the p38 signaling pathway in CFTR plasmid-transfected KYSE 170 cells. Immunohistochemical staining revealed a relationship between the CFTR expression pattern at the invasive front and the pN category. A relationship was also observed between the weak expression of CFTR at the invasive front and a shorter postoperative survival in a prognostic analysis.

CONCLUSIONS

The overexpression of CFTR in ESCC activated the p38 signaling pathway and was associated with a good patient prognosis. These results indicate the potential of CFTR as a mediator of and/or a biomarker for ESCC.

MicroRNA-1246 regulates proliferation, invasion, and differentiation in human vascular smooth muscle cells by targeting cystic fibrosis transmembrane conductance regulator (CFTR)

MicroRNA (miRNA) plays a key role in the proliferation and invasion of vascular smooth muscle cells (VSMCs). However, the role and underlying mechanism of miRNAs in VSMCs are not fully understood. Therefore, this study was designed to investigate the role and mechanism of microRNA-1246 (miR-1246) in VSMCs. VSMCs were cultured, and the proliferation of VSMCs was stimulated by platelet-derived growth factor (PDGF-BB) or 15% fetal bovine serum (FBS). The quantitative reverse transcription PCR (qRT-PCR) was used to detect the expression levels of miR-1246 and cystic fibrosis transmembrane conductance regulator (CFTR) in VSMCs. The CCK-8 assay and transwell assay were used to detect the proliferation and invasion of VSMCs. Target gene prediction and screening and luciferase reporter assays were used to verify downstream target genes of miR-1246. Western blotting was used to detect the protein expression levels of PCNA, α-SMA, SM-MHC, Collagen-1, and Cyclin D1 in VSMCs. PDGF-BB and FBS treatment induced VSMCs proliferation and the upregulation of miR-1246 expression. Overexpression of miR-1246 promoted VSMCs proliferation, invasion, and differentiation towards synthetic phenotype, while knockdown of miR-1246 had opposite effects. In addition, CFTR was found to be a direct target for miR-1246, and miR-1246 inhibited the expression of CFTR. Moreover, overexpression of CFTR inhibited VSMC proliferation and synthetic differentiation, while overexpression of miR-1246 partly abolished the effects of CFTR overexpression on VSMCs proliferation and differentiation. Our data suggest that MiR-1246 promotes VSMC proliferation, invasion, and differentiation to synthetic phenotype by regulating CFTR. MiR-1246 may be a potential therapeutic target for atherosclerosis.

A bird eye view on cystic fibrosis: An underestimated multifaceted chronic disorder

Cystic fibrosis (CF) is an autosomal recessive disease which involves the mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF involves in the inflammatory processes and is considered as a multisystem disorder that is not confined to lungs, but it also affects other vital organs that leads to numerous co-morbidities. The respiratory disorder in the CF results in mortality and morbidity which is characterized by series of serious events involving mucus hypersecretion, microbial infections, airways obstruction, inflammation, destruction of epithelium, tissue remodeling and terminal lung diseases. Mucins are the high molecular weight glycoproteins important for the viscoelastic properties of the mucus, play a significant role in the disease mechanisms. Determining the functional association between the CFTR and mucins might help to identify the putative target for specific therapeutic approach. In fact, furin enzyme which helps in the entry of novel COVID-19 virus into the cell, is upregulated in CF and this can also serve as a potential target for CF treatment. Moreover, the use of nano-formulations for CF treatment is an area of research being widely studied as they have also demonstrated promising outcomes. The in-depth knowledge of non-coding RNAs like miRNAs and lncRNAs and their functional association with CFTR gene expression and mutation can provide a different range of opportunity to identify the promising therapeutic approaches for CF.

Genomic stability at the coding regions of the multidrug transporter gene ABCB1: insights into the development of alternative drug resistance mechanisms in human leukemia cells

AIM

Despite considerable efforts to reverse clinical multidrug resistance (MDR), targeting the predominant multidrug transporter ABCB1/P-glycoprotein (P-gp) using small molecule inhibitors has been unsuccessful, possibly due to the emergence of alternative drug resistance mechanisms. However, the non-specific P-gp inhibitor cyclosporine (CsA) showed significant clinical benefits in patients with acute myeloid leukemia (AML), which likely represents the only proof-of-principle clinical trial using several generations of MDR inhibitors. Nevertheless, the mutational mechanisms that may underlie unsuccessful MDR modulation by CsA are not elucidated because of the absence of CsA-relevant cellular models. In this study, our aims were to establish CsA-resistant leukemia models and to examine the presence or absence of ABCB1 exonic mutations in these models as well as in diverse types of human cancer samples including AMLs.

METHODS

Drug-resistant lines were established by stepwise drug co-selection and characterized by drug sensitivity assay, rhodamine-123 accumulation, [3H]-labeled drug export, ABCB1 cDNA sequencing, and RNase protection assay. The genomic stability of the ABCB1 coding regions was evaluated by exome sequencing analysis of variant allele frequencies in human populations. Moreover, the mutational spectrum of ABCB1 was further assessed in diverse types of cancer samples including AMLs in the Cancer Genome Atlas (TCGA) at the National Cancer Institute.

RESULTS

We report the development of two erythroleukemia variants, RVC and RDC, which were derived by stepwise co-selection of K562/R7 drug-resistant leukemia cells with the etoposide-CsA and doxorubicin-CsA drug combinations, respectively. Interestingly, both RVC and RDC cell lines, which retained P-gp expression, showed altered multidrug-resistant phenotypes that were resistant to CsA modulation. Strikingly, no mutations were found in the ABCB1 coding regions in these variant cells even under long-term stringent drug selection. Genomically, ABCB1 displayed relatively low variant allele frequencies in human populations when compared with several ABC superfamily members. Moreover, ABCB1 also exhibited a very low mutational frequency in AMLs compared with all types of human cancer. In addition, we found that CsA played a role in undermining the selection of highly drug-resistant cells via induction of low-level and unstable drug resistance.

CONCLUSION

Our data indicate that ABCB1 coding regions are genomically stable and relatively resistant to drug-induced mutations. Non-ABCB1 mutational mechanisms are responsible for the drug-resistant phenotypes in both RVC and RDC cell lines, which are also prevalent in clinical AML patients. Accordingly, we propose several relevant models that account for the development of alternative drug resistance mechanisms in the absence of ABCB1 mutations.

Mutant CFTR Drives TWIST1 mediated epithelial-mesenchymal transition

Cystic fibrosis (CF) is a monogenetic disease resulting from mutations in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene encoding an anion channel. Recent evidence indicates that CFTR plays a role in other cellular processes, namely in development, cellular differentiation and wound healing. Accordingly, CFTR has been proposed to function as a tumour suppressor in a wide range of cancers. Along these lines, CF was recently suggested to be associated with epithelial–mesenchymal transition (EMT), a latent developmental process, which can be re-activated in fibrosis and cancer. However, it is unknown whether EMT is indeed active in CF and if EMT is triggered by dysfunctional CFTR itself or a consequence of secondary complications of CF. In this study, we investigated the occurrence of EMT in airways native tissue, primary cells and cell lines expressing mutant CFTR through the expression of epithelial and mesenchymal markers as well as EMT-associated transcription factors. Transepithelial electrical resistance, proliferation and regeneration rates, and cell resistance to TGF-β1induced EMT were also measured. CF tissues/cells expressing mutant CFTR displayed several signs of active EMT, namely: destructured epithelial proteins, defective cell junctions, increased levels of mesenchymal markers and EMT-associated transcription factors, hyper-proliferation and impaired wound healing. Importantly, we found evidence that the mutant CFTR triggered EMT was mediated by EMT-associated transcription factor TWIST1. Further, our data show that CF cells are over-sensitive to EMT but the CF EMT phenotype can be reversed by CFTR modulator drugs. Altogether, these results identify for the first time that EMT is intrinsically triggered by the absence of functional CFTR through a TWIST1 dependent mechanism and indicate that CFTR plays a direct role in EMT protection. This mechanistic link is a plausible explanation for the high incidence of fibrosis and cancer in CF, as well as for the role of CFTR as tumour suppressor protein.

MicroRNA-193b regulates human ovarian cancer cell growth via targeting STMN1

Ovarian cancer is the eighth most common malignancy among women worldwide. Ovarian cancer exhibits no obvious symptoms in the early stage of tumorigenesis and currently, no effective methods for the early detection and treatment of ovarian cancer have been established. Therefore, the identification of novel targets is critical to the early diagnosis and clinical treatment of ovarian cancer. microRNAs (miRs) are small non-coding RNAs, which serve an important biological role in a number of physiological processes and in oncogenesis. Previous studies have reported that miRNA-193b is dysregulated in a variety of types of human cancer. However, the roles of miRNA-193b in human ovarian cancer has not been determined. The present study investigated the roles of miRNA-193b in human ovarian cancer cells. Reverse transcription-quantitative PCR results indicated that the expression of miRNA-193b in ovarian cancer cells was significantly down-regulated compared with non-malignant cells. Cell counting kit-8 results indicated that the up-regulation of miRNA-193b inhibited ovarian cancer cell proliferation and induced ovarian cancer cell apoptosis. The present study also indicated that stathmin 1 (STMN1) was a direct target of miRNA-193b, and the up-regulation of miRNA-193b significantly decreased the expression of STMN1 in ovarian cancer cells. In conclusion, the results demonstrated that miRNA-193b serves as a tumor suppressor in human ovarian cancer by inhibiting cell proliferation and inducing cell apoptosis. Therefore, the assessment of miRNA-193b may provide insight into a novel diagnostic biomarker and potential therapeutic target for patients with ovarian cancer.

Pathological role of ion channels and transporters in the development and progression of triple-negative breast cancer

Breast cancer is a common malignancy in women. Among breast cancer types, triple-negative breast cancer (TNBC) tends to affect younger women, is prone to axillary lymph node, lung, and bone metastases; and has a high recurrence rate. Due to a lack of classic biomarkers, the currently available treatments are surgery and chemotherapy; no targeted standard treatment options are available. Therefore, it is urgent to find a novel and effective therapeutic target. As alteration of ion channels and transporters in normal mammary cells may affect cell growth, resulting in the development and progression of TNBC, ion channels and transporters may be promising new therapeutic targets for TNBC. This review summarizes ion channels and transporters related to TNBC and may provide new tumor biomarkers and help in the development of novel targeted therapies.

Potential role of CFTR in bisphenol A-induced malignant transformation of prostate cells via mitochondrial apoptosis

Bisphenol A (BPA) is an environmental endocrine disruptor and a risk factor for prostate cancer. The cystic fibrosis transmembrane conductance regulator (CFTR) is proposed to be a prostate cancer suppressor in some recent researches. However, the potential role and mechanism of CFTR in BPA-induced prostate cancer cells has not been well identified. In this study, BPA decreased the viability of human normal prostate RWPE-1 cells detected with a CCK-8 kit. The capacity of the cell line on soft agar colony formation, wound healing, and transwell invasion indicated malignant transformation induced by BPA. Western blot analysis demonstrated that the levels of CFTR and Bcl-2 decreased, whereas Bax level increased, and ELISA detection showed a decreased ATP level in BPA-exposed cells. Cell apoptosis was analyzed with Annexin V-FITC Detection Kit by flow cytometry. However, no significant difference was observed in cell viability and apoptosis rates compared to normal RWPE-1 cells. Our research revealed a potential role of CFTR in BPA-induced malignant transformation via mitochondrial apoptosis of normal prostate cells.

CFTR Regulates the Proliferation, Migration and Invasion of Cervical Cancer Cells by Inhibiting the NF-κB Signalling Pathway

Background

The cystic fibrosis transmembrane conductance regulator (CFTR) and nuclear factor κB (NF-κB) signalling pathways are currently regarded as co-regulators of the occurrence of cervical cancer. However, the detailed mechanism of CFTR- and NF-κB-mediated effects in cervical cancer remains to be elucidated. This study aimed to investigate the mechanism by which CFTR and NF-κB influence the development of cervical cancer.

Patients and Methods

CFTR ΔF508 mutation and CFTR promoter methylation were detected in cervical tissue samples. NF-κB p65 and IκBα protein levels were tested in HeLa cells with CFTR overexpression and knockdown by Western blotting. The effects of CFTR on cell proliferation, migration, and invasion were examined in HeLa cells by WST-1 and soft agar assays, cell wound scratch assay, and Matrigel invasion assays, respectively. The protein–protein interaction (PPI) network was constructed by using GeneMANIA. GeneCoDis3 was used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis on genes in the PPI network.

Results

CFTR mutation and CFTR promoter methylation were not associated with the occurrence of cervical cancer. NF-κB p65 protein levels were decreased in CFTR overexpression lines and increased in CFTR knockdown lines, and IκBα levels were affected in the opposite manner, indicating that CFTR inhibited the NF-κB signalling pathway. CFTR also regulated the cell proliferation, migration, and invasion ability of cervical cancer cells. When CFTR was overexpressed, cell proliferation, migration, and invasion ability were decreased. There were 20 genes that interacted with CFTR. KEGG pathway analysis showed enrichment in the gastric acid secretion, chemokine signalling, bile secretion and apoptosis pathways.

Conclusion

CFTR plays an important role in cancer cell proliferation, migration and invasion by inhibiting the NF-κB signalling pathway in cervical cancer.

CFTR Functions as a Tumor Suppressor and Is Regulated by DNA Methylation in Colorectal Cancer

Purpose

Cystic fibrosis transmembrane conductance regulator (CFTR) was shown to be downregulated or silenced in carcinomas and acts as a candidate tumor suppressor gene. However, the function of CFTR gene in colorectal cancer (CRC) is still unclear. This aim of this study was to investigate the CFTR promoter methylation status and its impact on the expression and functional role of CFTR in CRC development.

Patients and Methods

CFTR expression in CRC tissues and CRC cell lines was detected via quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). The promoter methylation status of CFTR was measured using methylation-specific PCR (MSP). colony formation, transwell, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were used to evaluate the effect of CFTR overexpression in CRC cell lines.

Results

qRT-PCR and IHC results indicated that CFTR expression was downregulated in the CRC tissues compared to the adjacent normal tissues. The promoter methylation status of CFTR was further analyzed in 70 CRC specimens. MSP validation showed methylation of CFTR promoter in 62.2% (45/70) of CRC tissues. The methylation of CFTR promoter was significantly associated with age (P=0.013) and lymph node metastasis (P=0.026) in CRC tissues. Results of transwell, MTT, and colony formation assays showed that CFTR overexpression inhibited the migration, invasion, and proliferation of CRC cells.

Conclusion

CFTR expression was downregulated in CRC and promoter methylation may be responsible for this downregulation. Overexpression of CFTR may suppress CRC tumor growth by inhibiting the proliferation, migration, and invasion of CRC cells. CFTR promoter methylation was significantly correlated with lymph node metastasis; thus, CFTR may be a potential marker for lymph node metastasis of CRC.

CFTR promotes malignant glioma development via up-regulation of Akt/Bcl2-mediated anti-apoptosis pathway

Cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP‐activated Cl^‐ channel, is extensively expressed in the epithelial cells of various tissues and organs. Accumulating evidence indicates that aberrant expression or mutation of CFTR is related to carcinoma development. Malignant gliomas are the most common and aggressive intracranial tumours; however, the role of CFTR in the development of malignant gliomas is unclear. Here, we report that CFTR is expressed in malignant glioma cell lines. Suppression of CFTR channel function or knockdown of CFTR suppresses glioma cell viability whereas overexpression of CFTR promotes it. Additionally, overexpression of CFTR suppresses apoptosis and promotes glioma progression in both subcutaneous and orthotopic xenograft models. Cystic fibrosis transmembrane conductance regulator activates Akt/Bcl2 pathway, and suppression of PI3K/Akt pathway abolishes CFTR overexpression–induced up‐regulation of Bcl2 (MK‐2206 and LY294002) and cell viability (MK‐2206). More importantly, the protein expression level of CFTR is significantly increased in glioblastoma patient samples. Altogether, our study has revealed a mechanism by which CFTR promotes glioma progression via up‐regulation of Akt/Bcl2‐mediated anti‐apoptotic pathway, which warrants future studies into the potential of using CFTR as a therapeutic target for glioma treatment.

What Role Does CFTR Play in Development, Differentiation, Regeneration and Cancer?

One of the key features associated with the substantial increase in life expectancy for individuals with CF is an elevated predisposition to cancer, firmly established by recent studies involving large cohorts. With the recent advances in cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies and the increased long-term survival rate of individuals with cystic fibrosis (CF), this is a novel challenge emerging at the forefront of this disease. However, the mechanisms linking dysfunctional CFTR to carcinogenesis have yet to be unravelled. Clues to this challenging open question emerge from key findings in an increasing number of studies showing that CFTR plays a role in fundamental cellular processes such as foetal development, epithelial differentiation/polarization, and regeneration, as well as in epithelial–mesenchymal transition (EMT). Here, we provide state-of-the-art descriptions on the moonlight roles of CFTR in these processes, highlighting how they can contribute to novel therapeutic strategies. However, such roles are still largely unknown, so we need rapid progress in the elucidation of the underlying mechanisms to find the answers and thus tailor the most appropriate therapeutic approaches.

Cystic Fibrosis, CFTR, and Colorectal Cancer

Cystic fibrosis (CF), caused by biallelic inactivating mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, has recently been categorized as a familial colorectal cancer (CRC) syndrome. CF patients are highly susceptible to early, aggressive colorectal tumor development. Endoscopic screening studies have revealed that by the age of forty 50% of CF patients will develop adenomas, with 25% developing aggressive advanced adenomas, some of which will have already advanced to adenocarcinomas. This enhanced risk has led to new CF colorectal cancer screening recommendations, lowering the initiation of endoscopic screening to age forty in CF patients, and to age thirty in organ transplant recipients. The enhanced risk for CRC also extends to the millions of people (more than 10 million in the US) who are heterozygous carriers of CFTR gene mutations. Further, lowered expression of CFTR is reported in sporadic CRC, where downregulation of CFTR is associated with poor survival. Mechanisms underlying the actions of CFTR as a tumor suppressor are not clearly understood. Dysregulation of Wnt/β-catenin signaling and disruption of intestinal stem cell homeostasis and intestinal barrier integrity, as well as intestinal dysbiosis, immune cell infiltration, stress responses, and intestinal inflammation have all been reported in human CF patients and in animal models. Notably, the development of new drug modalities to treat non-gastrointestinal pathologies in CF patients, especially pulmonary disease, offers hope that these drugs could be repurposed for gastrointestinal cancers.

Epigenetic Modification of CFTR in Head and Neck Cancer

Cystic fibrosis transmembrane conductance regulator (CFTR), a cyclic AMP (cAMP)-regulated chloride channel, is critical for secretion and absorption across diverse epithelia. Mutations or absence of CFTR result in pathogeneses, including cancer. While CFTR has been proposed as a tumor suppressing gene in tumors of the intestine, lung, and breast cancers, its effects in head and neck cancer (HNC) have yet to be investigated. This study aimed to define expression patterns and epigenetic modifications of CFTR in HNC. CFTR was expressed in normal but not in HNC cells and tissues. Treatment with 5-aza-2'-deoxycytidine (5-Aza-CdR) was associated with rescued expression of CFTR, whose function was confirmed by patch clamp technique. Further experiments demonstrated that CFTR CpG islands were hypermethylated in cancer cells and tissues and hypomethylated in normal cells and tissue. Our results suggest that CFTR epigenetic modifications are critical in both down-regulation and up-regulation of CFTR expression in HNC and normal cells respectively. We then investigated the impact of CFTR on expressions and functions of cancer-related genes. CFTR silencing was closely associated with changes to other cancer-related genes, suppressing apoptosis while enhancing proliferation, cell motility, and invasion in HNC. Our findings demonstrate that hypermethylation of CFTR CpG islands and CFTR deficiency is closely related to HNC.

Promoter hypermethylation of the CFTR gene as a novel diagnostic and prognostic marker of breast cancer

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer-related deaths among women. New biomarkers with definite diagnostic and prognostic efficacy are urgently needed. Here, we showed that the promoter of the cystic fibrosis transmembrane conductance regulator (CFTR) was hypermethylated in breast cancer. The messenger RNA level of CFTR was downregulated in breast cancer. Notably, all 19 breast cancer patients with hypermethylated CFTR were diagnosed with invasive carcinoma. Moreover, CFTR was upregulated in decitabine (10 μM) treated breast cancer cells. Overexpression of CFTR inhibited cell growth whereas knockdown of CFTR promoted cell invasion. In the tissue array analysis, the CFTR protein level decreased significantly in breast cancer and low CFTR protein level correlated with poor survival with a P-value of 0.034. Thus, promoter hypermethylation of the CFTR gene might be a novel diagnostic marker of breast cancer.

Role of ion channels in gastrointestinal cancer

In their seminal papers Hanahan and Weinberg described oncogenic processes a normal cell undergoes to be transformed into a cancer cell. The functions of ion channels in the gastrointestinal (GI) tract influence a variety of cellular processes, many of which overlap with these hallmarks of cancer. In this review we focus on the roles of the calcium (Ca2+), sodium (Na+), potassium (K+), chloride (Cl-) and zinc (Zn2+) transporters in GI cancer, with a special emphasis on the roles of the KCNQ1 K+ channel and CFTR Cl- channel in colorectal cancer (CRC). Ca2+ is a ubiquitous second messenger, serving as a signaling molecule for a variety of cellular processes such as control of the cell cycle, apoptosis, and migration. Various members of the TRP superfamily, including TRPM8, TRPM7, TRPM6 and TRPM2, have been implicated in GI cancers, especially through overexpression in pancreatic adenocarcinomas and down-regulation in colon cancer. Voltage-gated sodium channels (VGSCs) are classically associated with the initiation and conduction of action potentials in electrically excitable cells such as neurons and muscle cells. The VGSC NaV1.5 is abundantly expressed in human colorectal CRC cell lines as well as being highly expressed in primary CRC samples. Studies have demonstrated that conductance through NaV1.5 contributes significantly to CRC cell invasiveness and cancer progression. Zn2+ transporters of the ZIP/SLC39A and ZnT/SLC30A families are dysregulated in all major GI organ cancers, in particular, ZIP4 up-regulation in pancreatic cancer (PC). More than 70 K+ channel genes, clustered in four families, are found expressed in the GI tract, where they regulate a range of cellular processes, including gastrin secretion in the stomach and anion secretion and fluid balance in the intestinal tract. Several distinct types of K+ channels are found dysregulated in the GI tract. Notable are hERG1 upregulation in PC, gastric cancer (GC) and CRC, leading to enhanced cancer angiogenesis and invasion, and KCNQ1 down-regulation in CRC, where KCNQ1 expression is associated with enhanced disease-free survival in stage II, III, and IV disease. Cl- channels are critical for a range of cellular and tissue processes in the GI tract, especially fluid balance in the colon. Most notable is CFTR, whose deficiency leads to mucus blockage, microbial dysbiosis and inflammation in the intestinal tract. CFTR is a tumor suppressor in several GI cancers. Cystic fibrosis patients are at a significant risk for CRC and low levels of CFTR expression are associated with poor overall disease-free survival in sporadic CRC. Two other classes of chloride channels that are dysregulated in GI cancers are the chloride intracellular channels (CLIC1, 3 & 4) and the chloride channel accessory proteins (CLCA1,2,4). CLIC1 & 4 are upregulated in PC, GC, gallbladder cancer, and CRC, while the CLCA proteins have been reported to be down-regulated in CRC. In summary, it is clear, from the diverse influences of ion channels, that their aberrant expression and/or activity can contribute to malignant transformation and tumor progression. Further, because ion channels are often localized to the plasma membrane and subject to multiple layers of regulation, they represent promising clinical targets for therapeutic intervention including the repurposing of current drugs.

Dual-strand tumor suppressor miR-193b-3p and -5p inhibit malignant phenotypes of lung cancer by suppressing their common targets

Emerging studies suggest that microRNAs (miRNAs) play multiple roles in cancer malignancy, including proliferation and acquisition of metastatic potential. Differentially expressed miRNAs responsible for the malignancy of lung cancer were searched by miRNA microarray using a previously established brain metastatic lung cancer model. Twenty-five miRNAs were down-regulated in brain metastatic lung cancer cells. Among those, miR-193b-3p and -5p were chosen for further studies. Their function in metastatic potential and proliferation was examined using Transwell invasion, wound healing, and colony forming assays. The underlying mechanism of tumor-suppressor miR-193b-3p and -5p was explored using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), Western blot, Argonaute 2-RNA immunoprecipitation (Ago2-RIP), and reporter assays. Both strands of miR-193b were down-regulated in brain metastatic lung cancer cells and in tissues from lung cancer patients. Overexpression of miR-193b-3p and -5p inhibited invasive and migratory activities and diminished clonogenic ability. Conversely, inhibition of miR-193b-3p or -5p increased the metastatic potential and colony forming ability. Cyclin D1 (CCND1), Ajuba LIM Protein (AJUBA), and heart development protein with EGF like domains 1 (HEG1) were identified as common target genes of miR-193b-3p and -5p. A reporter assay and an Ago2-RIP experiment showed that both miRNAs directly bind to the 3′ untranslated region (3′UTR) of the target mRNA. Knockdown of target gene reduced the proliferative and metastatic potential of primary and metastatic lung cancer cells. Our results demonstrate miR-193b is a dual-strand tumor suppressor and a novel therapeutic target for lung cancer.

A novel role and mechanism of cystic fibrosis transmembrane conductance regulator in bisphenol A-induced prostate cancer

Bisphenol A (BPA) is a well known environmental endocrine disruptor that may cause human prostate cancer through disturbing cell mitosis, proliferation, and apoptosis. As one of the most important anion channels in organisms, cystic fibrosis transmembrane conductance regulator (CFTR) is proposed as a tumor suppressor in carcinogenesis and development of prostate cancer in recent studies. Whether CFTR plays a role in BPA-induced prostate cancer needs to be further identified. In this study, two prostate cancer cell lines PC-3 and LNCaP were exposed to BPA for detecting the cytotoxic reactions by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and enzyme-linked immunosorbent assays. After the treatment with BPA for 24 hours, the cell viability was decreased significantly with increased cell apoptosis in the two cell lines. Moreover, both PC-3 and LNCaP cells had a reduced expression level of cAMP, CFTR, and adenosine triphosphate upon BPA treatment. In addition, AMPKα kinase was found upregulated to promote cell apoptosis through increasing Bax expression and decreasing Bcl-2 expression. Our study suggests a role and mechanism of CFTR in BPA-induced prostate cancer via cell apoptosis for the first time.

CFTR interacts with Hsp90 and regulates the phosphorylation of AKT and ERK1/2 in colorectal cancer cells

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF cells and tissues exhibit various mitochondrial abnormalities. However, the underlying molecular mechanisms remain elusive. Here, we examined the mechanisms through which CFTR regulates Bcl‐2 family proteins, which in turn regulate permeabilization of the mitochondrial outer membrane. Notably, inhibition of CFTR activated Bax and Bad, but inhibited Bcl‐2. Moreover, degradation of phosphorylated extracellular signal‐regulated kinase 1/2 (ERK1/2) and AKT increased significantly in CFTR‐knockdown cells. Dysfunction of CFTR decreased heat‐shock protein 90 (Hsp90) mRNA levels, and CFTR was found to interact with Hsp90. Inhibition of Hsp90 by SNX‐2112 induced the degradation of phosphorylated AKT and ERK1/2 in Caco2 and HRT18 cells. These findings may help provide insights into the physiological role of CFTR in CF‐related diseases.

Mechanosensitive ion channels push cancer progression

In many cases, the mechanical properties of a tumor are different from those of the host tissue. Mechanical cues regulate cancer development by affecting both tumor cells and their microenvironment, by altering cell migration, proliferation, extracellular matrix remodeling and metastatic spread. Cancer cells sense mechanical stimuli such as tissue stiffness, shear stress, tissue pressure of the extracellular space (outside-in mechanosensation). These mechanical cues are transduced into a cellular response (e. g. cell migration and proliferation; inside-in mechanotransduction) or to a response affecting the microenvironment (e. g. inducing a fibrosis or building up growth-induced pressure; inside-out mechanotransduction). These processes heavily rely on mechanosensitive membrane proteins, prominently ion channels. Mechanosensitive ion channels are involved in the Ca²⁺-signaling of the tumor and stroma cells, both directly, by mediating Ca²⁺ influx (e. g. Piezo and TRP channels), or indirectly, by maintaining the electrochemical gradient necessary for Ca²⁺ influx (e. g. K_2P, K_Ca channels). This review aims to discuss the diverse roles of mechanosenstive ion channels in cancer progression, especially those involved in Ca²⁺-signaling, by pinpointing their functional relevance in tumor pathophysiology.

CFTR constrains the differentiation from mouse embryonic stem cells to intestine lineage cells

Cystic fibrosis transmembrane conductance regulator (CFTR) is a transmembrane Cl^- and HCO₃^- transporter and its malfunction leads to cystic fibrosis (CF) and multiple congenital diseases. The most common mutation in CF patient is DF508 and the patients have increased risk in developing gastrointestinal tumors. To explore the etiology of high cancer risk in DF508-CF patients, we have derived mouse DF508-CFTR embryonic stem (ES) cells and use it as a novel in vitro model to study the role of CFTR from developmental angle. We found the self-renewal properties are intact in DF508-CFTR ES cells. Nevertheless, the differentiation of intestine lineage, the expression of intestine progenitor and major intestine differentiated cell markers is significantly upregulated in DF508-CFTR ES cell differentiated cells. Therefore, CFTR plays an important role in intestine lineage differentiation. Besides, DF508-CFTR ES cells formed teratomas demonstrated enhanced expressions of cell proliferation, migration and epithelial-mesenchymal transition associated marker genes, indicating the tumor suppressive role of CFTR. Taken together, our derived DF508-CFTR ES cells can serve as a new model to study the etiology of CF disease in vitro and malignant teratoma formation in vivo.

miR-193: A new weapon against cancer

microRNAs (miRNAs) are known as a large group of short noncoding RNAs, which structurally consist of 19-22 nucleotides in length and functionally act as one of the main regulators of gene expression in important biological and physiological contexts like cell growth, apoptosis, proliferation, differentiation, movement (cell motility), and angiogenesis as well as disease formation and progression importantly in cancer cell invasion, migration, and metastasis. Among these notable tiny molecules, many studies recently presented the important role of the miR-193 family comprising miR-193a-3p, miR-193a-5p, miR-193b-3p, and miR-193b-5p in health and disease biological processes by interaction with special targeting and signaling, which mainly contribute as a tumor suppressor. Therefore, in the present paper, we review the functional role of this miRNA family in both health and disease conditions focusing on various tumor developments, diagnoses, prognoses, and treatment.

MicroRNA-645 targets urokinase plasminogen activator and decreases the invasive growth of MDA-MB-231 triple-negative breast cancer cells

Background

Urokinase plasminogen activator (uPA) promotes the in vivo invasive growth of HCC cells by cleaving and activating matrix metalloproteinases (MMPs) to induce the destruction of the extracellular matrix of triple-negative breast cancer (TNBC) cells. The identification of microRNAs that target uPA and decrease uPA expression would be useful for attenuating the in vivo invasive growth of TNBC cells.

Materials and methods

MicroRNA-645 (miR-645) was identified using an online tool (miRDB) as potentially targeting uPA; miR-645 inhibition of uPA was confirmed by western blot experiments. The effects of miR-645 on the in vivo invasive growth of TNBC cells were examined using an intrahepatic tumor model in nude mice, and the miR-645 mechanism of action was explored with MMP cleaving experiments.

Results

Through virtual screening, we discovered that miR-645 potentially targeted the uPA 3′ untranslated region. This targeting was confirmed by western blot experiments and miR-645 lentiviral particle (LV-645) transduction that inhibited uPA expression in MDA-MB-231 TNBC cells. The LV-645 inhibition of uPA led to the decreased invasive growth of TNBC cells in nude mice. The mechanism data indicated that the uPA inhibition resulted in a decreased cleaving of the pro-MMP-9 protein.

Conclusion

Targeting uPA with miR-645 decreased the in vivo invasive growth of TNBC cells. These results suggest that miR-645 may represent a promising treatment strategy for TNBC.

The Clinical Biology of Cystic Fibrosis Transmembrane Regulator Protein: Its Role and Function in Extrapulmonary Disease

Normal cystic fibrosis (CF) transmembrane regulator (CFTR) protein has multiple functions in health and disease. Many mutations in the CFTR gene produce abnormal or absent protein. CFTR protein dysfunction underlies the classic CF phenotype of progressive pulmonary and GI pathology but may underlie diseases not usually associated with CF. This review highlights selected extrapulmonary disease that may be associated with abnormal CFTR. Increasing survival in CF is associated with increasing incidence of diseases associated with aging. CFTR dysfunction in older individuals may have novel effects on glucose metabolism, control of insulin release, regulation of circadian rhythm, and cancer cell pathophysiology. In individuals who have cancers with acquired CFTR suppression, their tumors may more likely exhibit rapid expansion, epithelial-to-mesenchymal transformation, abnormally reduced apoptosis, and increased metastatic potential. The new modulators of CFTR protein synthesis could facilitate the additional exploration needed to better understand the unfolding clinical biology of CFTR in human disease, even as they revolutionize treatment of patients with CF.

Pancreatitis-Associated Genes and Pancreatic Cancer Risk: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of this study was to evaluate the connection between pancreatic cancer (PC) and genetic variants associated with chronic pancreatitis via systematic review and meta-analysis.

METHODS

The data search was performed in 3 major databases (PubMed, Embase, and Cochrane Library). The selected studies have looked into the presence of the pancreatitis-associated genes in patients with PC and in control subjects, the outcome being the frequency of the mutations in the 2 groups. For the binary outcomes, pooled odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

Ten articles proved to be eligible for the qualitative synthesis, and 8 articles were suitable for statistical analysis. Six case-control studies, comprising 929 PC cases and 1890 control subjects for serine protease inhibitor Kazal type 1 (SPINK1) mutations, and 5 case-control studies, comprising 1674 PC cases and 19,036 control subjects for CFTR mutations, were enrolled in our analysis. SPINK1 mutations showed no association with PC (OR, 1.52; 95% CI, 0.67-3.45; P = 0.315), whereas mutations in CFTR modestly increased the risk of PC (OR, 1.41; 95% CI, 1.07-1.84; P = 0.013).

CONCLUSION

Our meta-analysis showed that mutations in CFTR modestly increase the risk of PC, whereas no association was found between SPINK1 and PC.

Identification of common differentially-expressed miRNAs in ovarian cancer cells and their exosomes compared with normal ovarian surface epithelial cell cells

The aim of the present study was to identify common microRNAs (miRNAs) in ovarian cancer (OC) cells and their exosomes using microarray data (accession number GSE76449) available from the Gene Expression Omnibus database, including exosomal samples from 3 OC cell lines, 1 normal ovarian surface epithelial cell line and their original cell samples. Differentially-expressed miRNAs (DE-miRNAs) were identified using the Linear Models for Microarray data method, and mRNA targets of DE-miRNAs were predicted using the miRWalk2 database. The potential functions of the target genes of the DE-miRNAs were analyzed using the Database for Annotation, Visualization and Integrated Discovery tool. The association between crucial miRNAs and target genes, and their clinical associations, were validated using The Cancer Genome Atlas data. As a result, 12 upregulated and 12 downregulated DE-miRNAs were shared by the 3 OC cell lines compared with normal controls in the exosomal samples, while 5 upregulated and 65 downregulated DE-miRNAs were shared between the original cells. Among them, 9 downregulated DE-miRNAs were shared between exosomal and original cells. The target genes of 4 common DE-miRNAs between exosomal and original cells (miR-127-3p, miR-339-5p, miR-409-3p and miR-654-3p) were predicted. Functional enrichment analysis indicated that these target genes may be involved in the Wnt signaling pathway (miR-409-3p-CTBP1 and miR-339-5p-CHD8) and Proteoglycans in cancer (miR-127-3p-PPP1CA). The negative associations between these 3 miRNAs and target genes were confirmed by a Pearson's correlation analysis. miR-127 was negatively associated with tumor grade. In conclusion, our results describe a set of miRNAs involved in OC development, in exosomal and non-exosomal manners, by regulating their target genes. They may be potential targets for treatment of OC.

Cystic fibrosis transmembrane conductance regulator-emerging regulator of cancer

Mutations of cystic fibrosis transmembrane conductance regulator (CFTR) cause cystic fibrosis, the most common life-limiting recessive genetic disease among Caucasians. CFTR mutations have also been linked to increased risk of various cancers but remained controversial for a long time. Recent studies have begun to reveal that CFTR is not merely an ion channel but also an important regulator of cancer development and progression with multiple signaling pathways identified. In this review, we will first present clinical findings showing the correlation of genetic mutations or aberrant expression of CFTR with cancer incidence in multiple cancers. We will then focus on the roles of CFTR in fundamental cellular processes including transformation, survival, proliferation, migration, invasion and epithelial-mesenchymal transition in cancer cells, highlighting the signaling pathways involved. Finally, the association of CFTR expression levels with patient prognosis, and the potential of CFTR as a cancer prognosis indicator in human malignancies will be discussed.

Role of iodide metabolism in physiology and cancer

Iodide (I^-) metabolism is crucial for the synthesis of thyroid hormones (THs) in the thyroid and the subsequent action of these hormones in the organism. I^- is principally transported by the sodium iodide symporter (NIS) and by the anion exchanger PENDRIN, and recent studies have demonstrated the direct participation of new transporters including anoctamin 1 (ANO1), cystic fibrosis transmembrane conductance regulator (CFTR) and sodium multivitamin transporter (SMVT). Several of these transporters have been found expressed in various tissues, implicating them in I^- recycling. New research supports the exciting idea that I^- participates as a protective antioxidant and can be oxidized to hypoiodite, a potent oxidant involved in the host defense against microorganisms. This was possibly the original role of I^- in biological systems, before the appearance of TH in evolution. I^- per se participates in its own regulation, and new evidence indicates that it may be antineoplastic, anti-proliferative and cytotoxic in human cancer. Alterations in the expression of I^- transporters are associated with tumor development in a cancer-type-dependent manner and, accordingly, NIS, CFTR and ANO1 have been proposed as tumor markers. Radioactive iodide has been the mainstay adjuvant treatment for thyroid cancer for the last seven decades by virtue of its active transport by NIS. The rapid advancement of techniques that detect radioisotopes, in particular I^-, has made NIS a preferred target-specific theranostic agent.

High CFTR expression in Philadelphia chromosome-positive acute leukemia protects and maintains continuous activation of BCR-ABL and related signaling pathways in combination with PP2A

Cystic fibrosis transmembrane conductance regulator (CFTR) is classified as an anion channel transporter of Cl- and HCO3-. Through interactions with its PDZ domain, CFTR is capable of regulating other proteins, such as protein phosphatase 2A (PP2A). The aberrant expression and mutation of CFTR have been observed in several tumor, but not in philadelphia chromosome-positive(Ph+) acute leukemia, including Ph+ B cell acute lymphoblastic leukemia(Ph+ B-ALL) and chronic myelogenous leukemia blast crisis phases (CML-BC). In this study, we demonstrated the mean expression level of CFTR in Ph+ acute leukemia cells was markedly higher than that in Ph- B-ALL and CML-chronic phase cells. CFTRinh-172, a classic CFTR inhibitor, down-regulated the expression of CFTR, p-BCR-ABL and classical Wnt/β-catenin signaling in Ph+ acute leukemia cells, while imatinib had no effect on CFTR. Importantly, reduced efficacy of CFTRinh-172 was closely associated with elevated PP2A phosphatase activity. Furthermore, we confirmed an interaction between CFTR and the PP2AA subunit in K562 cells. In addition, we demonstrated CFTR and PP2AA interact in the cytosol, resulting in PP2A complex inactivation and increased degradation of PP2A substrates via the lysosomal/proteasome pathway. In conclusion, our results showed CFTR was highly expressed in Ph+ acute leukemia, which protected and maintained the continuous activation of BCR-ABL and the canonical Wnt/β-catenin signaling pathway by decreasing PP2A phosphatase activity. According to this working model of the CFTR-PP2A-BCR-ABL axis, targeting the CFTR protein will activate PP2A and may offer a new treatment strategy for Ph+ acute leukemia, especially for patients exhibiting high levels of CFTR expression.

CFTR is a potential marker for nasopharyngeal carcinoma prognosis and metastasis

While there is an increasing interest in the correlation of cystic fibrosis transmembrane conductance regulator (CFTR) and cancer incidence, the role of CFTR in nasopharyngeal carcinoma (NPC) development remains unknown. In this study, we aimed to explore the prognostic value of CFTR in NPC patients. The expression of CFTR was determined in NPC cell lines and tissues. Statistical analysis was utilized to evaluate the correlation between CFTR expression levels and clinicopathological characteristics and prognosis in 225 cases of NPC patients. The results showed that CFTR was down-regulated in NPC tissues and cell lines. Low expression of CFTR was correlated with advanced stage (p = 0.026), distant metastasis (p < 0.001) and poor prognosis (p < 0.01). Multivariate analysis identified CFTR as an independent prognostic factor (p = 0.003). Additionally, wound healing and transwell assays revealed that overexpression of CFTR inhibited NPC cell migration and invasion, whereas knockdown of CFTR promoted cell migration and invasion. Thus, the current study indicates that CFTR, as demonstrated to play an important role in tumor migration and invasion, may be used as a potential prognostic indicator in NPC.

Retrospective screening of microarray data to identify candidate IFN-inducible genes in a HTLV-1 transformed model

HuT-102 cells are considered one of the most representable human T-lymphotropic virus 1 (HTLV-1)-infected cell lines for studying adult T-cell lymphoma (ATL). In our previous studies, genome-wide screening was performed using the GeneChip system with Human Genome Array U133 Plus 2.0 for transforming growth factor-β-activated kinase 1 (TAK1)-, interferon regulatory factor 3 (IRF3)- and IRF4-regulated genes to demonstrate the effects of interferon-inducible genes in HuT-102 cells. Our previous findings demonstrated that TAK1 induced interferon inducible genes via an IRF3-dependent pathway and that IRF4 has a counteracting effect. As our previous data was performed by manual selection of common interferon-related genes mentioned in the literature, there has been some obscure genes that have not been considered. In an attempt to maximize the outcome of those microarrays, the present study reanalyzed the data collected in previous studies through a set of computational rules implemented using ‘R’ software, to identify important candidate genes that have been missed in the previous two studies. The final list obtained consisted of ten genes that are highly recommend as potential candidate for therapies targeting the HTLV-1 infected cancer cells. Those genes are ATM, CFTR, MUC4, PARP14, QK1, UBR2, CLEC7A (Dectin-1), L3MBTL, SEC24D and TMEM140. Notably, PARP14 has gained increased attention as a promising target in cancer cells.

Homocysteine activates autophagy by inhibition of CFTR expression via interaction between DNA methylation and H3K27me3 in mouse liver

Elevated homocysteine (Hcy) levels have been reported to be involved in liver injury, and autophagy plays an important role in normal hepatic physiology and pathophysiology, but the mechanism underlying Hcy regulated autophagy is currently unknown. In this study, CBS^+/- mice were fed with regular diet for 12 weeks to establish a hyperhomocysteinemia (HHcy) model and HL-7702 cells were treated with Hcy, we found that Hcy increases autophagy and aggravates liver injury by downregulation of cystic fibrosis transmembrane conductance regulator (CFTR) expression in vivo and in vitro. Overexpression of CFTR inhibited the formation of autophagosomes and the expression of autophagy-related proteins BECN1, LC3-II/I and Atg12, while the expression of p62 increased in Hcy-treated hepatocytes and CBS^+/- mice injected with lentivirus expressing CFTR. Further study showed that CFTR expression is regulated by the interaction of DNA methyltransferase 1 (DNMT1) and enhancer of zeste homolog 2 (EZH2), which, respectively, regulate DNA methylation and histone H3 lysine 27 trimethylation (H3K27me3). In conclusion, our study showed that Hcy activates autophagy by inhibition of CFTR expression via interaction between H3K27me3 and DNA methylation in the mouse liver. These findings provide new insight into the mechanism of Hcy-induced autophagy in liver injury.