The Eag potassium channel as a new prognostic marker in ovarian cancer

Liensinine, a Novel and Food-Derived Compound, Exerts Potent Antihepatoma Efficacy via Inhibiting the Kv10.1 Channel

Plant metabolites from natural product extracts offer unique advantages against carcinogenesis in the development of drugs. The target-based virtual screening from food-derived compounds represents a promising approach for tumor therapy. In this study, we performed virtual screening to target the presumed inhibitor-binding pocket and identified a highly potent Kv10.1 inhibitor, liensinine (Lien), which can inhibit the channel in a dose-dependent way with an IC50 of 0.24 ± 0.07 μM. Combining molecular dynamics simulations with mutagenesis experiments, our data show that Lien interacts with Kv10.1 by binding with Y539, T543, D551, E553, and H601 in the C-linker domain of Kv10.1. In addition, the interaction of sequence alignment and 3D structural modeling revealed differences between the C-linker domain of the Kv10.1 channel and the Kv11.1 channel. Furthermore, antitumor experiments revealed that Lien suppresses the proliferation and migration of HCC both in vitro and in vivo. In summary, the food-derived compound, Lien, may serve as a lead compound for antihepatoma therapeutic drugs targeting Kv10.1.

Targeting the hERG1 and β1 integrin complex for cancer treatment

INTRODUCTION

Despite great advances, novel therapeutic targets and strategies are still needed, in particular for some carcinomas in the metastatic stage (breast cancer, colorectal cancer, pancreatic ductal adenocarcinoma and the clear cell renal carcinoma). Ion channels may be considered good cancer biomarkers and targets for antineoplastic therapy. These concepts are particularly relevant considering the hERG1 potassium channel as a novel target for antineoplastic therapy.

AREAS COVERED

A great deal of evidence demonstrates that hERG1 is aberrantly expressed in human cancers, in particular in aggressive carcinomas. A relevant cornerstone was the discovery that, in cancer cells, the channel is present in a very peculiar conformation, strictly bound to the β1 subunit of integrin receptors. The hERG1/β1 integrin complex does not occur in the heart. Starting from this evidence, we developed a novel single chain bispecific antibody (scDb-hERG1-β1), which specifically targets the hERG1/β1 integrin complex and exerts antineoplastic effects in preclinical experiments.

EXPERT OPINION

Since hERG1 blockade cannot be pursued for antineoplastic therapy due to the severe cardiac toxic effects (ventricular arrhythmias) that many hERG1 blockers exert, different strategies must be identified to specifically target hERG1 in cancer. The targeting of the hERG1/β1 integrin complex through the bispecific antibody scDb-hERG1-β1 can overcome such hindrances.

Corydaline binds to a druggable pocket of hEAG1 channel and inhibits hepatic carcinoma cell viability

Ether-à-go-go (EAG) potassium channels play a crucial role in the regulation of neuronal excitability and cancer progression, rendering them potential drug targets for cancer therapy. However, the scarcity of information regarding the selection sites on hEAG1 has posed a challenge in the discovery of new hEAG1 inhibitors. In this study, we introduced a novel natural product, corydaline, which selectively inhibits the hEAG1 channel without sensitivity to other KCNH channels. The IC50 of corydaline for the hEAG1 channel was 11.3 ± 0.6 μM, whereas the IC50 for hEAG2 and hERG1 were 73.6 ± 9.9 μM and 111.4 ± 8.5 μM, respectively. Molecular dynamics simulations together with site-directed mutagenesis, have unveiled that the site corydaline forms interactions with Lys217, Phe273, Pro276, Trp295 and Arg366, situated within the intracellular transmembrane segments S1-S4 of the voltage-sensor domain, be considered a novel drug pocket for hEAG1. Additionally, the intergaration of sequence alignment and 3D structural modeling revealed differences between the voltage sensor domain of hEAG1 channel and other EAG channels, suggesting the feasibility of a VSD modulation approach that could potentially lead to the selective inhibition of hEAG1 channels. Furthermore, antitumor experiments demonstrated that corydaline can inhibit the proliferation and migration of hepatic carcinoma cells by targeting hEAG1. The identification of this novel druggable pocket offers the possibility for drug screening against diseases linked to abnormal hEAG1 channels.

Ion Channels and Personalized Medicine in Gynecological Cancers

Targeted therapy against cancer plays a key role in delivering safer and more efficient treatments. In the last decades, ion channels have been studied for their participation in oncogenic processes because their aberrant expression and/or function have been associated with different types of malignancies, including ovarian, cervical, and endometrial cancer. The altered expression or function of several ion channels have been associated with tumor aggressiveness, increased proliferation, migration, invasion, and metastasis of cancer cells and with poor prognosis in gynecological cancer patients. Most ion channels are integral membrane proteins easily accessible by drugs. Interestingly, a plethora of ion channel blockers have demonstrated anticancer activity. Consequently, some ion channels have been proposed as oncogenes, cancer, and prognostic biomarkers, as well as therapeutic targets in gynecological cancers. Here, we review the association of ion channels with the properties of cancer cells in these tumors, which makes them very promising candidates to be exploited in personalized medicine. The detailed analysis of the expression pattern and function of ion channels could help to improve the clinical outcomes in gynecological cancer patients.

New Diarylamine KV10.1 Inhibitors and Their Anticancer Potential

Expression of the voltage-gated potassium channel K_V10.1 (Eag1) has been detected in over 70% of human cancers, making the channel a promising new target for new anticancer drug discovery. A new structural class of K_V10.1 inhibitors was prepared by structural optimisation and exploration of the structure–activity relationship of the previously published hit compound ZVS-08 (1) and its optimised analogue 2. The potency and selectivity of the new inhibitors between K_V10.1 and hERG were investigated using whole-cell patch-clamp experiments. We obtained two new optimised K_V10.1 inhibitors, 17a and 18b, with improved nanomolar IC₅₀ values of 568 nM and 214 nM, respectively. Compound 17a exhibited better ratio between IC₅₀ values for hEAG1 and hERG than previously published diarylamine inhibitors. Compounds 17a and 18b moderately inhibited the growth of the K_V10.1-expressing cell line MCF-7 in two independent assays. In addition, 17a and 18b also inhibited the growth of hERG-expressing Panc-1 cells with higher potency compared with MCF-7 cells. The main obstacle for newly developed diarylamine K_V10.1 inhibitors remains the selectivity toward the hERG channel, which needs to be addressed with targeted drug design strategies in the future.

The Kv10.1 Channel: A Promising Target in Cancer

Carcinogenesis is a multistage process involving the dysregulation of multiple genes, proteins, and pathways that make any normal cell acquire a cancer cell phenotype. Therefore, it is no surprise that numerous ion channels could be involved in this process. Since their discovery and subsequent cloning, ion channels have been established as therapeutic targets in excitable cell pathologies (e.g., cardiac arrhythmias or epilepsy); however, their involvement in non-excitable cell pathologies is relatively recent. Among all ion channels, the voltage-gated potassium channels Kv10.1 have been established as a promising target in cancer treatment due to their high expression in tumoral tissues compared to low levels in healthy tissues.

Dynamics and physiological meaning of complexes between ion channels and integrin receptors: the case of Kv11.1

The cellular functions are regulated by a complex interplay of diffuse and local signals. Experimental work in cell physiology has led to recognize that understanding a cell's dynamics requires a deep comprehension of local fluctuations of cytosolic regulators. Macromolecular complexes are major determinants of local signaling. Multi-enzyme assemblies limit the diffusion restriction to reaction kinetics by direct exchange of metabolites. Likewise, close coupling of ion channels and transporters modulate the ion concentration around a channel mouth or transporter binding site. Extreme signal locality is brought about by conformational coupling between membrane proteins, as is typical of mechanotransduction. A paradigmatic case is integrin-mediated cell adhesion. Sensing the extracellular microenvironment and providing an appropriate response is essential in growth and development and has innumerable pathological implications. The process involves bidirectional signal transduction by complex supra-molecular structures that link integrin receptors to ion channels and transporters, growth factor receptors, cytoskeletal elements and other regulatory elements. The dynamics of such complexes is only beginning to be understood. A thoroughly studied example is the association between integrin receptors and the voltage-gated K+ channels Kv11.1. These channels are widely expressed in early embryos, where their physiological roles are poorly understood and apparently different from the shaping of action potential firing in the adult. Hints about these roles come from studies in cancer cells, where Kv11.1 is often overexpressed and appears to re-assume functions, such as controlling cell proliferation/differentiation, apoptosis and migration. Kv11.1 is implicated in these processes through its linking to integrin subunits.

Creating a Novel Mathematical Model of the Kv10.1 Ion Channel and Controlling Channel Activity with Nanoelectromechanical Systems

The use of nanoelectromechanical systems or nanorobots offers a new concept for sensing and controlling subcellular structures, such as ion channels. We present here a novel method for mathematical modeling of ion channels based on control system theory and system identification. We investigated the use of nanoelectromechanical devices to control the activity of ion channels, particularly the activity of the voltage-gated ion channel Kv10.1, an important channel in cancer development and progression. A mathematical model of the dynamic behavior of the selected ion channel Kv10.1 in the Laplace (s) domain was developed, which is given in the representation of a transfer function. In addition, we addressed the possibilities of controlling ion channel activity by nanoelectromechanical devices and nanorobots and finally presented a control algorithm for the Kv10.1 as a control object. A use case demonstrates the potential of a Kv10.1 controlled nanorobot for cancer treatment at a single-cell level.

Overcoming challenges of HERG potassium channel liability through rational design: Eag1 inhibitors for cancer treatment

Two decades of research have proven the relevance of ion channel expression for tumor progression in virtually every indication, and it has become clear that inhibition of specific ion channels will eventually become part of the oncology therapeutic arsenal. However, ion channels play relevant roles in all aspects of physiology, and specificity for the tumor tissue remains a challenge to avoid undesired effects. Eag1 (K_V 10.1) is a voltage-gated potassium channel whose expression is very restricted in healthy tissues outside of the brain, while it is overexpressed in 70% of human tumors. Inhibition of Eag1 reduces tumor growth, but the search for potent inhibitors for tumor therapy suffers from the structural similarities with the cardiac HERG channel, a major off-target. Existing inhibitors show low specificity between the two channels, and screenings for Eag1 binders are prone to enrichment in compounds that also bind HERG. Rational drug design requires knowledge of the structure of the target and the understanding of structure-function relationships. Recent studies have shown subtle structural differences between Eag1 and HERG channels with profound functional impact. Thus, although both targets' structure is likely too similar to identify leads that exclusively bind to one of the channels, the structural information combined with the new knowledge of the functional relevance of particular residues or areas suggests the possibility of selective targeting of Eag1 in cancer therapies. Further development of selective Eag1 inhibitors can lead to first-in-class compounds for the treatment of different cancers.

3D Pharmacophore-Based Discovery of Novel KV10.1 Inhibitors with Antiproliferative Activity

Simple Summary

A novel structural class of inhibitors of the voltage-gated potassium channel K_V10.1 was discovered by a ligand-based drug design method using a 3D pharmacophore model. The virtual screening hit compound ZVS-08 inhibited the channel in a voltage-dependent manner consistent with the action of a gating modifier. Structure–activity relationship studies revealed a nanomolar K_V10.1 inhibitor that is selective for some K_V and Na_V channels but exhibits significant inhibition of the hERG channel. K_V10.1 inhibitor 1 inhibited the growth of the MCF-7 cell line expressing high levels of K_V10.1 and low levels of hERG more potently than the Panc1 cell line (no K_V10.1 and high hERG expression). Moreover, the K_V10.1 inhibitor 1 induced significant apoptosis in tumour spheroids of Colo-357 cells. This study may provide a basis for the use of computational drug design methods for the discovery of novel K_V10.1 inhibitors as new promising anticancer drugs.

Abstract

(1) Background: The voltage-gated potassium channel K_V10.1 (Eag1) is considered a near- universal tumour marker and represents a promising new target for the discovery of novel anticancer drugs. (2) Methods: We utilized the ligand-based drug discovery methodology using 3D pharmacophore modelling and medicinal chemistry approaches to prepare a novel structural class of K_V10.1 inhibitors. Whole-cell patch clamp experiments were used to investigate potency, selectivity, kinetics and mode of inhibition. Anticancer activity was determined using 2D and 3D cell-based models. (3) Results: The virtual screening hit compound ZVS-08 discovered by 3D pharmacophore modelling exhibited an IC₅₀ value of 3.70 µM against K_V10.1 and inhibited the channel in a voltage-dependent manner consistent with the action of a gating modifier. Structural optimization resulted in the most potent K_V10.1 inhibitor of the series with an IC₅₀ value of 740 nM, which was potent on the MCF-7 cell line expressing high K_V10.1 levels and low hERG levels, induced significant apoptosis in tumour spheroids of Colo-357 cells and was not mutagenic. (4) Conclusions: Computational ligand-based drug design methods can be successful in the discovery of new potent K_V10.1 inhibitors. The main problem in the field of K_V10.1 inhibitors remains selectivity against the hERG channel, which needs to be addressed in the future also with target-based drug design methods.

Emerging Roles for Ion Channels in Ovarian Cancer: Pathomechanisms and Pharmacological Treatment

Ovarian cancer (OC) is the deadliest gynecologic cancer, due to late diagnosis, development of platinum resistance, and inadequate alternative therapy. It has been demonstrated that membrane ion channels play important roles in cancer processes, including cell proliferation, apoptosis, motility, and invasion. Here, we review the contribution of ion channels in the development and progression of OC, evaluating their potential in clinical management. Increased expression of voltage-gated and epithelial sodium channels has been detected in OC cells and tissues and shown to be involved in cancer proliferation and invasion. Potassium and calcium channels have been found to play a critical role in the control of cell cycle and in the resistance to apoptosis, promoting tumor growth and recurrence. Overexpression of chloride and transient receptor potential channels was found both in vitro and in vivo, supporting their contribution to OC. Furthermore, ion channels have been shown to influence the sensitivity of OC cells to neoplastic drugs, suggesting a critical role in chemotherapy resistance. The study of ion channels expression and function in OC can improve our understanding of pathophysiology and pave the way for identifying ion channels as potential targets for tumor diagnosis and treatment.

KCNN4 is a diagnostic and prognostic biomarker that promotes papillary thyroid cancer progression

The incidence of thyroid cancer remains high worldwide, and papillary thyroid cancer (PTC) is the most common type. Potassium Calcium-Activated Channel Subfamily N Member 4 (KCNN4) has been reported as an oncogene in various cancers. We examined expression of KCNN4 in public databases and discovered that it is upregulated in PTC. We verified this finding using our own validated cohort and RNA sequencing data. We also found that KCNN4 is a diagnostic and prognostic biomarker that is associated with disease-free survival, immune infiltration, and several other clinicopathological features of PTC. Gene Set Enrichment Analysis indicated that apoptotic and epithelial-mesenchymal transition gene sets are both upregulated in PTC patients with higher KCNN4 levels. In PTC cell lines, silencing KCNN4 inhibited cell proliferation, migration and invasion. Moreover, quantitative real-time PCR and Western blotting indicated that silencing KCNN4 increased expression of apoptotic genes in PTC cells and reduced the expression of genes involved in their epithelial-mesenchymal transition. These results suggest that KCNN4 promotes PTC progression by inducing epithelial-mesenchymal transition and suppressing apoptosis, which suggests KCNN4 may be a useful diagnostic and prognostic biomarker of PTC.

Kv10.1 Regulates Microtubule Dynamics during Mitosis

Kv10.1 (potassium voltage-gated channel subfamily H member 1, known as EAG1 or Ether-à-go-go 1), is a voltage-gated potassium channel, prevailingly expressed in the central nervous system. The aberrant expression of Kv10.1 is detected in over 70% of all human tumor tissues and correlates with poorer prognosis. In peripheral tissues, Kv10.1 is expressed almost exclusively during the G2/M phase of the cell cycle and regulates its progression-downregulation of Kv10.1 extends the duration of the G2/M phase both in cancer and healthy cells. Here, using biochemical and imaging techniques, such as live-cell measurements of microtubule growth and of cytosolic calcium, we elucidate the mechanisms of Kv10.1-mediated regulation at the G2/M phase. We show that Kv10.1 has a dual effect on mitotic microtubule dynamics. Through the functional interaction with ORAI1 (calcium release-activated calcium channel protein 1), it modulates cytosolic calcium oscillations, thereby changing microtubule behavior. The inhibition of either Kv10.1 or ORAI1 stabilizes the microtubules. In contrast, the knockdown of Kv10.1 increases the dynamicity of mitotic microtubules, resulting in a stronger spindle assembly checkpoint, greater mitotic spindle angle, and a decrease in lagging chromosomes. Understanding of Kv10.1-mediated modulation of the microtubule architecture will help to comprehend how cancer tissue benefits from the presence of Kv10.1, and thereby increase the efficacy and safety of Kv10.1-directed therapeutic strategies.

Epileptogenesis and oncogenesis: An antineoplastic role for antiepileptic drugs in brain tumours?

The first description of epileptic seizures due to brain tumours occurred in 19th century. Nevertheless, after over one hundred years, scientific literature is still lacking on how epilepsy and its treatment can affect tumour burden, progression and clinical outcomes. In patients with brain tumours, epilepsy dramatically impacts their quality of life (QoL). Even antiepileptic therapy seems to affect tumor lesion development. Numerous studies suggest that certain actors involved in epileptogenesis (inflammatory changes, glutamate and its ionotropic and metabotropic receptors, GABA-A and its GABA-AR receptor, as well as certain ligand- and voltage-gated ion channel) may also contribute to tumorigenesis. Although some antiepileptic drugs (AEDs) are known operating on such mechanisms underlying epilepsy and tumor development, few preclinical and clinical studies have tried to investigate them as targets of pharmacological tools acting to control both phenomena. The primary aim of this review is to summarize known determinants and pathophysiological mechanisms of seizures, as well as of cell growth and spread, in patients with brain tumors. Therefore, a special focus will be provided on the anticancer effects of commonly prescribed AEDs (including levetiracetam, valproic acid, oxcarbazepine and others), with an overview of both preclinical and clinical data. Potential clinical applications of this finding are discussed.

HERG channel and cancer: A mechanistic review of carcinogenic processes and therapeutic potential

The human ether-à-go-go related gene (HERG) encodes the alpha subunit of Kv11.1, which is a voltage-gated K⁺ channel protein mainly expressed in heart and brain tissue. HERG plays critical role in cardiac repolarization, and mutations in HERG can cause long QT syndrome. More recently, evidence has emerged that HERG channels are aberrantly expressed in many kinds of cancer cells and play important roles in cancer progression. HERG could therefore be a potential biomarker for cancer and a possible molecular target for anticancer drug design. HERG affects a number of cellular processes, including cell proliferation, apoptosis, angiogenesis and migration, any of which could be affected by dysregulation of HERG. This review provides an overview of available information on HERG channel as it relates to cancer, with focus on the mechanism by which HERG influences cancer progression. Molecular docking attempts suggest two possible protein-protein interactions of HERG with the ß1-integrin receptor and the transcription factor STAT-1 as novel HERG-directed therapeutic targeting which avoids possible cardiotoxicity. The role of epigenetics in regulating HERG channel expression and activity in cancer will also be discussed. Finally, given its inherent extracellular accessibility as an ion channel, we discuss regulatory roles of this molecule in cancer physiology and therapeutic potential. Future research should be directed to explore the possibilities of therapeutic interventions targeting HERG channels while minding possible complications.

Antibodies Targeting KV Potassium Channels: A Promising Treatment for Cancer

Voltage-gated potassium channels are transmembrane proteins that allow flow of potassium across the membrane to regulate ion homeostasis, cell proliferation, migration, cell volume, and specific processes such as muscular contraction. Aberrant function or expression of potassium channels can underlie pathologies ranging from heart arrhythmia to cancer; the expression of potassium channels is altered in many types of cancer and that alteration correlates with malignancy and poor prognosis. Targeting potassium channels therefore constitutes a promising approach for cancer therapy. In this review, we discuss strategies to target a particular family of potassium channels, the voltage-gated potassium channels (K_V) where a reasonable structural understanding is available. We also discuss the possible obstacles and advantages of such a strategy.

Potassium and Sodium Channels and the Warburg Effect: Biophysical Regulation of Cancer Metabolism

Ion channels are progressively emerging as a novel class of membrane proteins expressed in several types of human cancers and regulating the different aspects of cancer cell behavior. The metabolism of cancer cells, usually composed by a variable proportion of respiration, glycolysis, and glutaminolysis, leads to the excessive production of acidic metabolic products. The presence of these acidic metabolites inside the cells results in intracellular acidosis, and hinders survival and proliferation. For this reason, tumor cells activate mechanisms of pH control that produce a constitutive increase in intracellular pH (pHi) that is more acidic than the extracellular pH (pHe). This condition forms a perfect microenvironment for metastatic progression and may be permissive for some of the acquired characteristics of tumors. Recent analyses have revealed complex interconnections between oncogenic activation, ion channels, hypoxia signaling and metabolic pathways that are dysregulated in cancer. Here, we summarize the molecular mechanisms of the Warburg effect and hypoxia and their association. Moreover, we discuss the recent findings concerning the involvement of ion channels in various aspects of the Warburg effect and hypoxia, focusing on the role of Na+ and K+ channels in hypoxic and metabolic reprogramming in cancer.

Ion Channel Targeting with Antibodies and Antibody Fragments for Cancer Diagnosis

The antibody era has greatly impacted cancer management in recent decades. Indeed, antibodies are currently applied for both cancer diagnosis and therapy. For example, monoclonal antibodies are the main constituents of several in vitro diagnostics, which are applied at many levels of cancer diagnosis. Moreover, the great improvement provided by in vivo imaging, especially for early-stage cancer diagnosis, has traced the path for the development of a complete new class of antibodies, i.e., engineered antibody fragments. The latter embody the optimal characteristics (e.g., low renal retention, rapid clearance, and small size) which make them ideal for in vivo applications. Furthermore, the present review focuses on reviewing the main applications of antibodies and antibody fragments for solid cancer diagnosis, both in vitro and in vivo. Furthermore, we review the scientific evidence showing that ion channels represent an almost unexplored class of ideal targets for both in vitro and in vivo diagnostic purposes. In particular, we review the applications, in solid cancers, of monoclonal antibodies and engineered antibody fragments targeting the voltage-dependent ion channel Kv 11.1, also known as hERG1.

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.

Repurposing old drugs in oncology: Opportunities with clinical and regulatory challenges ahead

WHAT IS KNOWN AND OBJECTIVE

In order to expedite the availability of drugs to treat cancers in a cost-effective manner, repurposing of old drugs for oncological indications is gathering momentum. Revolutionary advances in pharmacology and genomics have demonstrated many old drugs to have activity at novel antioncogenic pharmacological targets. We decided to investigate whether prospective studies support the promises of nonclinical and retrospective clinical studies on repurposing three old drugs, namely metformin, valproate and astemizole.

METHODS

We conducted an extensive literature search through PubMed to gather representative nonclinical and retrospective clinical studies that investigated the potential repurposing of these three drugs for oncological indications. We then searched for prospective studies aimed at confirming the promises of retrospective data.

RESULTS AND DISCUSSION

While evidence from nonclinical and retrospective clinical studies with these drugs appears highly promising, large scale prospective studies are either lacking or have failed to substantiate this promise. We provide a brief discussion of some of the challenges in repurposing. Principal challenges and obstacles relate to heterogeneity of cancers studied without considering their molecular signatures, trials with small sample size and short duration, failure consider issues of ethnicity of study population and effective antioncogenic doses of the drug studied.

WHAT IS NEW AND CONCLUSION

Well-designed prospective studies demonstrating efficacy are required for repurposing old drugs for oncology indications, just as they are for new chemical entities for any indication. Early and ongoing interactions with regulatory authorities are invaluable. We outline a tentative framework for a structured approach to repurposing old drugs for novel indications in oncology.

Blocking the Nav1.5 channel using eicosapentaenoic acid reduces migration and proliferation of ovarian cancer cells

Activity of the voltage-gated Nav1.5 sodium channel has been reported to be involved in cell proliferation, cancer invasion and gene expression. In addition, eicosapentaenoic acid (EPA) has recently been suggested to inhibit ovarian cancer cell growth and suppress tumor metastasis. The present study aimed to explore the association between EPA, the Nav1.5 sodium channel and ovarian cancer cells. Using patch-clamp technique and RNA interference approaches, sodium currents were recorded in epithelial ovarian cancer cells, and it was confirmed that the Nav1.5 channel carried the sodium currents. Furthermore, EPA effectively inhibited sodium currents in a dose-dependent manner, shifted the steady-state inactivation curve of sodium currents to the hyperpolarizing direction and reduced sodium window currents. In addition, EPA induced a shift in the inactivation curve in a dose-dependent manner. Inhibition of the sodium channel, either by EPA or by Nav1.5 knockdown, attenuated ovarian cancer cell migration and proliferation. To the best of our knowledge, the present study is the first to conduct sodium current recording in ovarian cancer cells, and revealed that EPA may inhibit Nav1.5-mediated ovarian cancer cell migration and growth. These findings not only present a potential prognostic biomarker for ovarian cancer, but also provide a strategy towards the development of novel pharmacological treatments for patients with ovarian cancer.

Low expression of KCNN3 may affect drug resistance in ovarian cancer

Drug resistance is a principal contributor to the poor prognosis of ovarian cancer (OC). Therefore, identifying factors that affect drug resistance in OC is critical. In the present study, 51 OC specimens from lab collections were immunohistochemically tested, public data for 489 samples from The Cancer Genome Atlas cohort and 1,656 samples from the Kaplan‑Meier Plotter were downloaded, and data were retrieved from Oncomine. It was identified that the mRNA and protein expression of the potassium calcium‑activated channel subfamily N member 3 (KCNN3) was markedly lower in OC tissues compared with normal tissues, and in drug‑resistant OC tissues compared with sensitive OC tissues. Low KCNN3 expression consistently predicted shorter disease‑free and overall survival (OS). Specifically, low KCNN3 expression predicted shorter OS in 395 patients with low expression levels of mucin‑16. There was additional evidence that KCNN3 expression is mediated by microRNA‑892b. Furthermore, text mining and analyses of protein and gene interactions indicated that KCNN3 affects drug resistance. To the best of the authors' knowledge, this is the first report to associate KCNN3 with poor prognosis and drug resistance in OC. The present findings indicated that KCNN3 is a potential prognostic marker and therapeutic target for OC.

Kv10.1 potassium channel: from the brain to the tumors

The KCNH1 gene encodes the Kv10.1 (Eag1) ion channel, a member of the EAG (ether-à-go-go) family of voltage-gated potassium channels. Recent studies have demonstrated that KCHN1 mutations are implicated in Temple–Baraitser and Zimmermann–Laband syndromes and other forms of developmental deficits that all present with mental retardation and epilepsy, suggesting that Kv10.1 might be important for cognitive development in humans. Although the Kv10.1 channel is mainly expressed in the mammalian brain, its ectopic expression occurs in 70% of human cancers. Cancer cells and tumors expressing Kv10.1 acquire selective advantages that favor cancer progression through molecular mechanisms that involve several cellular pathways, indicating that protein–protein interactions may be important for Kv10.1 influence in cell proliferation and tumorigenesis. Several studies on transcriptional and post-transcriptional regulation of Kv10.1 expression have shown interesting mechanistic insights about Kv10.1 role in oncogenesis, increasing the importance of identifying the cellular factors that regulate Kv10.1 expression in tumors.

APETx4, a Novel Sea Anemone Toxin and a Modulator of the Cancer-Relevant Potassium Channel KV10.1

The human ether-à-go-go channel (hEag1 or K_V10.1) is a cancer-relevant voltage-gated potassium channel that is overexpressed in a majority of human tumors. Peptides that are able to selectively inhibit this channel can be lead compounds in the search for new anticancer drugs. Here, we report the activity-guided purification and electrophysiological characterization of a novel K_V10.1 inhibitor from the sea anemone Anthopleura elegantissima. Purified sea anemone fractions were screened for inhibitory activity on K_V10.1 by measuring whole-cell currents as expressed in Xenopus laevis oocytes using the two-microelectrode voltage clamp technique. Fractions that showed activity on Kv10.1 were further purified by RP-HPLC. The amino acid sequence of the peptide was determined by a combination of MALDI- LIFT-TOF/TOF MS/MS and CID-ESI-FT-ICR MS/MS and showed a high similarity with APETx1 and APETx3 and was therefore named APETx4. Subsequently, the peptide was electrophysiologically characterized on K_V10.1. The selectivity of the toxin was investigated on an array of voltage-gated ion channels, including the cardiac human ether-à-go-go-related gene potassium channel (hERG or Kv11.1). The toxin inhibits K_V10.1 with an IC₅₀ value of 1.1 μM. In the presence of a similar toxin concentration, a shift of the activation curve towards more positive potentials was observed. Similar to the effect of the gating modifier toxin APETx1 on hERG, the inhibition of Kv10.1 by the isolated toxin is reduced at more positive voltages and the peptide seems to keep the channel in a closed state. Although the peptide also induces inhibitory effects on other K_V and Na_V channels, it exhibits no significant effect on hERG. Moreover, APETx4 induces a concentration-dependent cytotoxic and proapoptotic effect in various cancerous and noncancerous cell lines. This newly identified K_V10.1 inhibitor can be used as a tool to further characterize the oncogenic channel K_V10.1 or as a scaffold for the design and synthesis of more potent and safer anticancer drugs.

Periodic expression of Kv10.1 driven by pRb/E2F1 contributes to G2/M progression of cancer and non-transformed cells

Progression of cell cycle is associated with changes in K⁺ channel expression and activity. In this study, we report that Kv10.1, a K⁺ channel that increases cell proliferation and tumor growth, is regulated at the transcriptional level by the pRb/E2F1 pathway. De-repression of E2F1 by HPV-E7 oncoprotein leads to increased expression of Kv10.1. In proliferating cells, E2F1 transcription factor binds directly to the Kv10.1 promoter during (or close to) G2/M, resulting in transient expression of the channel. Importantly, this happens not only in cancer cells but also in non-transformed cells. Lack of Kv10.1 in both cancer and non-transformed cells resulted in prolonged G2/M phase, as indicated by phosphorylation of Cdk1 (Y15) and sustained pRb hyperphosphorylation. Our results strongly suggest that Kv10.1 expression is coupled to cell cycle progression and facilitates G2/M progression in both healthy and tumor cells.

Analysis of the expression of Kv10.1 potassium channel in patients with brain metastases and glioblastoma multiforme: impact on survival

Background

Kv10.1, a voltage-gated potassium channel only detected in the healthy brain, was found to be aberrantly expressed in extracerebral cancers. Investigations of Kv10.1 in brain metastasis and glioblastoma multiforme (GBM) are lacking.

Methods

We analyzed the expression of Kv10.1 by immunohistochemistry in these brain tumors (75 metastasis from different primary tumors, 71 GBM patients) and the influence of a therapy with tricyclic antidepressants (which are Kv10.1 blockers) on survival. We also investigated Kv10.1 expression in the corresponding primary carcinomas of metastases patients.

Results

We observed positive Kv10.1 expression in 85.3 % of the brain metastases and in 77.5 % of GBMs. Patients with brain metastases, showing low Kv10.1 expression, had a significantly longer overall survival compared to those patients with high Kv10.1 expression. Metastases patients displaying low Kv10.1 expression and also receiving tricyclic antidepressants showed a significantly longer median overall survival as compared to untreated patients.

Conclusions

Our data show that Kv10.1 is not only highly expressed in malignant tumors outside CNS, but also in the most frequent cerebral cancer entities, metastasis and GBM, which remain incurable in spite of aggressive multimodal therapies. Our results extend the correlation between dismal prognosis and Kv10.1 expression to patients with brain metastases or GBMs and, moreover, they strongly suggest a role of tricyclic antidepressants for personalized therapy of brain malignancies.

Expression of eag1 channel associated with the aggressive clinicopathological features and subtype of breast cancer

BACKGROUNDS

Expression of eag1 channel (Eag1) is associated with cell malignant transformation, tumor cell metastasis and poor prognosis of the patient. This study aimed at examining whether expression of the Eag1 associated with aggressive clinicopathological feature and the molecular subtype of breast cancer.

MATERIALS AND METHODS

109 patients who received breast cancer operation during January 2009 to December 2010 in Chinese-Japanese Friendship Hospital of Jilin University were recruited. We investigated the association of the Eag1 with clinicopathological features and molecular subtype of in triple negative breast cancer (TNBC) by univariate or multivariate analysis in a cross-section study.

RESULTS

The positive rate of Eag1 was 18.5% higher in TNBC compared with non-triple negative breast cancer (Non-TNBC) (P = 0.012, OR = 2.83, 95% CI = 2.16-3.47). Compared with the Eag1 negative group, the expression of Eag1 was linked to the larger tumor size (P = 0.002), advanced TNM stage (P = 0.029), high proportion of positive lymph node (87.6% vs. 65%, P = 0.014) and invasive ductal carcinoma (91% vs. 75%, P = 0.046).

CONCLUSIONS

The expression of Eag1 may be partially explained the aggressive behavior of TNBC in the breast cancer tissue.

hERG1 Potassium Channels: Novel Biomarkers in Human Solid Cancers

Because of their high incidence and mortality solid cancers are a major health problem worldwide. Although several new biomarkers and potential targets for therapy have been identified through biomolecular research in the last years, the effects on patients' outcome are still unsatisfactory. Increasing evidence indicates that hERG1 potassium channels are overexpressed in human primary cancers of different origin and several associations between hERG1 expression and clinicopathological features and/or outcome are emerging. Aberrant hERG1 expression may be exploited either for early diagnosis (especially in those cancers where it is expressed in the initial steps of tumor progression) or for therapy purposes. Indeed, hERG1 blockage impairs tumor cell growth both in vitro and in vivo in preclinical mouse model. hERG1-based tumor therapy in humans, however, encounters the major hindrance of the potential cardiotoxicity that many hERG1 blockers exert. In this review we focus on recent advances in translational research in some of the most frequent human solid cancers (breast, endometrium, ovary, pancreas, esophagus, stomach, and colorectum) that have been shown to express hERG1 and that are a major health problem.

Astemizole-based anticancer therapy for hepatocellular carcinoma (HCC), and Eag1 channels as potential early-stage markers of HCC

Hepatocellular carcinoma (HCC) has very poor prognosis. Astemizole has gained great interest as a potential anticancer drug because it targets several proteins involved in cancer including the Eag1 (ether à-go-go-1) potassium channel that is overexpressed in human HCC. Eag1 channels are regulated by cancer etiological factors and have been proposed as early tumor markers. Here, we found that HepG2 and HuH-7 HCC cells displayed Eag1 messenger RNA (mRNA) and protein expression, determined by real-time RT-PCR and immunochemistry, respectively. Astemizole inhibited human HCC cell proliferation (assessed by metabolic activity assay) and induced apoptosis (studied with flow cytometry) in both cell lines. The subcellular Eag1 protein localization was modified by astemizole in the HepG2 cells. The treatment with astemizole prevented diethylnitrosamine (DEN)-induced rat HCC development in vivo (followed by studying γ-glutamyl transpeptidase (GGT) activity). The Eag1 mRNA and protein levels were increased in most DEN-treated groups but decreased after astemizole treatment. GGT activity was decreased by astemizole. The Eag1 protein was detected in cirrhotic and dysplastic rat livers. Astemizole might have clinical utility for HCC prevention and treatment, and Eag1 channels may be potential early HCC biomarkers. These data provide significant basis to include astemizole in HCC clinical trials.

Antiproliferative and Proapoptotic Effects of Astemizole on Cervical Cancer Cells

Objective

Cervical cancer is a major cause of mortality among women in developing countries. Thus, it is necessary to offer novel therapies to treat this malignancy. Astemizole has been suggested as a novel and interesting anticancer agent because it targets several proteins involved in cancer including Eag1 (ether à-go-go-1) potassium channels. Eag1 has been proposed as a tumor marker for different types of cancer. Actually, we previously suggested Eag1 channels as cervical cancer and dysplasia markers. Besides, Eag1 has been proposed as a therapeutic target for different malignancies. However, the effect of astemizole in cervical cancer cells is unknown. Therefore, we investigated the effect of astemizole on the proliferation and apoptosis of cervical cancer cells.

Methods

Five cervical cancer cell lines (HeLa, SiHa, CaSki, INBL, and C-33A) were cultured according to manufacturer’s instructions. Eag1 protein expression was studied by immunocytochemistry. Cell proliferation was assayed with the MTT method, and apoptosis was investigated by flow cytometry.

Results

Eag1 protein expression was observed in different cell lines. Astemizole decreased cell proliferation in up to 40% and increased apoptosis severalfold in all the cell lines studied.

Conclusions

Our results suggest astemizole as a potential therapy for cervical cancer.

Positive correlation between the expression of hEag1 and HIF-1α in breast cancers: an observational study

OBJECTIVES

To explore the expression patterns of Eag1 (ether á go-go 1) and HIF-1α (hypoxia-inducible factor 1α) in a cohort of patients with breast cancer.

SETTING

Department of general surgery in an upper first-class hospital in Xi'an, China.

PARTICIPANTS

A total of 112 female Han Chinese patients with a diagnosis of invasive ductal carcinoma were included. Patients with main internal diseases, such as cardiovascular, endocrine, gastroenterological, haematological, infectious diseases, etc, were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

Expression profiles of Eag1 and HIF-1α.

RESULTS

Eag1 and HIF-1α were overexpressed in the tumour tissues compared with the pair-matched control tissues, p=0.002 and <0.001, respectively. The expression of Eag1 and HIF-1α was negatively correlated with tumour size, p=0.032 and p=0.025, respectively, and lymph node status (p=0.040, p=0.032, respectively). The coexpression of Eag1 and HIF-1α was correlated with tumour size (p=0.012), lymph node status (p=0.027) and tumour stage (p=0.036). HIF-1α has a strong correlation with hEag1 expression (κ=0.731, p<0.001).

CONCLUSIONS

HIF-1α expression has a strong correlation with hEag1 expression. We are the first to attempt to explore the correlation at the population level.

Regulation of hERG and hEAG channels by Src and by SHP-1 tyrosine phosphatase via an ITIM region in the cyclic nucleotide binding domain

Members of the EAG K⁺ channel superfamily (EAG/Kv10.x, ERG/Kv11.x, ELK/Kv12.x subfamilies) are expressed in many cells and tissues. In particular, two prototypes, EAG1/Kv10.1/KCNH1 and ERG1/Kv11.1/KCNH2 contribute to both normal and pathological functions. Proliferation of numerous cancer cells depends on hEAG1, and in some cases, hERG. hERG is best known for contributing to the cardiac action potential, and for numerous channel mutations that underlie ‘long-QT syndrome’. Many cells, particularly cancer cells, express Src-family tyrosine kinases and SHP tyrosine phosphatases; and an imbalance in tyrosine phosphorylation can lead to malignancies, autoimmune diseases, and inflammatory disorders. Ion channel contributions to cell functions are governed, to a large degree, by post-translational modulation, especially phosphorylation. However, almost nothing is known about roles of specific tyrosine kinases and phosphatases in regulating K⁺ channels in the EAG superfamily. First, we show that tyrosine kinase inhibitor, PP1, and the selective Src inhibitory peptide, Src40-58, reduce the hERG current amplitude, without altering its voltage dependence or kinetics. PP1 similarly reduces the hEAG1 current. Surprisingly, an ‘immuno-receptor tyrosine inhibitory motif’ (ITIM) is present within the cyclic nucleotide binding domain of all EAG-superfamily members, and is conserved in the human, rat and mouse sequences. When tyrosine phosphorylated, this ITIM directly bound to and activated SHP-1 tyrosine phosphatase (PTP-1C/PTPN6/HCP); the first report that a portion of an ion channel is a binding site and activator of a tyrosine phosphatase. Both hERG and hEAG1 currents were decreased by applying active recombinant SHP-1, and increased by the inhibitory substrate-trapping SHP-1 mutant. Thus, hERG and hEAG1 currents are regulated by activated SHP-1, in a manner opposite to their regulation by Src. Given the widespread distribution of these channels, Src and SHP-1, this work has broad implications in cell signaling that controls survival, proliferation, differentiation, and other ERG1 and EAG1 functions in many cell types.

Potassium channels in cell cycle and cell proliferation

Normal cell-cycle progression is a crucial task for every multicellular organism, as it determines body size and shape, tissue renewal and senescence, and is also crucial for reproduction. On the other hand, dysregulation of the cell-cycle progression leading to uncontrolled cell proliferation is the hallmark of cancer. Therefore, it is not surprising that it is a tightly regulated process, with multifaceted and very complex control mechanisms. It is now well established that one of those mechanisms relies on ion channels, and in many cases specifically on potassium channels. Here, we summarize the possible mechanisms underlying the importance of potassium channels in cell-cycle control and briefly review some of the identified channels that illustrate the multiple ways in which this group of proteins can influence cell proliferation and modulate cell-cycle progression.

The roles of K(+) channels in cancer

Potassium channels are transmembrane proteins that selectively facilitate the flow of potassium ions down an electrochemical gradient. These molecules have been studied in great detail in the context of cell excitability, but their roles in less cell type-specific functions, such as cell proliferation, angiogenesis or cell migration, have only recently been assessed. Moreover, the importance of these channels for tumour biology has become evident. This, coupled with the fact that they are accessible proteins and that their pharmacology is well characterized, has increased the interest in investigating potassium channels as therapeutic targets in cancer patients.

KCNH1 potassium channels are expressed in cervical cytologies from pregnant patients and are regulated by progesterone

Potassium voltage-gated channel, subfamily H (eag-related), member 1 (KCNH1) potassium channels are potential tumour markers and cancer therapeutic targets and are up-regulated by oestrogens and human papilloma virus (HPV) oncogenes. However, the role of KCNH1 in normal tissues is poorly understood, and its expression in pregnancy is unknown. We wondered whether KCNH1 channels are expressed in cervical cells from pregnant patients and whether progesterone (P4) regulates KCNH1. The association with HPV was also investigated. KCNH1 protein expression was studied by immunocytochemistry in liquid-based cervical cytologies; 93 samples were obtained from pregnant patients at different trimesters, and 15 samples were obtained from non-pregnant women (controls). The presence ofHPVwas studied by PCR with direct sequencing and nested multiplex PCR. HeLa cervical cancer cells were transfected with human progesterone receptor-B (PR-B) and treated with P4.KCNH1mRNA expression in these cultures was studied by real-time PCR. KCNH1 protein was detected in 100% of the pregnancy samples and in 26% of the controls. We found 18 pregnant patients infected with HPV and detected 14 types ofHPV. There was no association between the percentage of cells expressing KCNH1 and either the presence or type of HPV. P4induced KCNH1 mRNA and protein expression in cells transfected with human PR-B. No regulation of KCNH1 by P4was observed in non-transfected cells. We show for the first time the expression of an ion channel during human pregnancy at different trimesters and KCNH1 regulation by P4in human cells. These data raise a new research field for KCNH1 channels in human tissues.

Clinicopathologic significance of claudin-6, occludin, and matrix metalloproteinases -2 expression in ovarian carcinoma

Background

Tight junctions (TJs) are mainly composed of claudins, occludin, and tight junction adhesion molecules (JAM). The invasive and metastatic phenotype of highly invasive cancer cells has been related to abnormal structure and function of TJs, and with expression of activated matrix metalloproteinases (MMPs). The relevance of these mechanisms responsible for the invasion and metastasis of ovarian carcinoma is unclear. Similarly, it is not known if the expression of claudin-6, occludin and MMP2 is related with the clinical properties of these tumors.

Methods

Expression of claudin-6, occludin, and MMP2 was detected in samples of human ovarian cancer tissues by immunohistochemistry and correlated with the clinical properties of the tumors.

Results

The positive expression rates of claudin-6 and MMP-2 were higher in ovarian papillary serous carcinomas than n ovarian serous adenomas (P < 0.05). There were no differences in the expression of occludin (P > 0.05). The expression of claudin-6 and occludin in ovarian cancer was not correlated with patient age, pathological grade, clinical stage, and metastasis (P > 0.05). MMP-2 expression was enhanced with increased clinical stage and metastasis (P < 0.05), but was unrelated to patient age or tumor grade (P > 0.05). There were no apparent correlations between expression of claudin-6, occludin and MMP-2 in ovarian cancer tissue (P > 0.05).

Conclusions

Our data suggest, for the first time, that the claudin-6 and MMP-2 are up-regulated in ovarian papillary serous carcinomas, MMP-2 expression was enhanced with increased clinical stage and metastasis. Claudin-6 and MMP-2 may play a positive role in the invasion and metastasis of ovarian cancer.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1775628454106511.

PIST (GOPC) modulates the oncogenic voltage-gated potassium channel KV10.1

Although crucial for their correct function, the mechanisms controlling surface expression of ion channels are poorly understood. In the case of the voltage-gated potassium channel KV10.1, this is determinant not only for its physiological function in brain, but also for its pathophysiology in tumors and possible use as a therapeutic target. The Golgi resident protein PIST binds several membrane proteins, thereby modulating their expression. Here we describe a PDZ domain-mediated interaction of KV10.1 and PIST, which enhances surface levels of KV10.1. The functional, but not the physical interaction of both proteins is dependent on the coiled-coil and PDZ domains of PIST; insertion of eight amino acids in the coiled-coil domain to render the neural form of PIST (nPIST) and the corresponding short isoform in an as-of-yet unknown form abolishes the effect. In addition, two new isoforms of PIST (sPIST and nsPIST) lacking nearly the complete PDZ domain were cloned and shown to be ubiquitously expressed. PIST and KV10.1 co-precipitate from native and expression systems. nPIST also showed interaction, but did not alter the functional expression of the channel. We could not document physical interaction between KV10.1 and sPIST, but it reduced KV10.1 functional expression in a dominant-negative manner. nsPIST showed weak physical interaction and no functional effect on KV10.1. We propose these isoforms to work as modulators of PIST function via regulating the binding on interaction partners.

Epigenome-wide ovarian cancer analysis identifies a methylation profile differentiating clear-cell histology with epigenetic silencing of the HERG K+ channel

Ovarian cancer remains the leading cause of death in women with gynecologic malignancies, despite surgical advances and the development of more effective chemotherapeutics. As increasing evidence indicates that clear-cell ovarian cancer may have unique pathogenesis, further understanding of molecular features may enable us to begin to understand the underlying biology and histology-specific information for improved outcomes. To study epigenetics in clear-cell ovarian cancer, fresh frozen tumor DNA (n = 485) was assayed on Illumina Infinium HumanMethylation450 BeadChips. We identified a clear-cell ovarian cancer tumor methylation profile (n = 163) which we validated in two independent replication sets (set 1, n = 163; set 2, n = 159), highlighting 22 CpG loci associated with nine genes (VWA1, FOXP1, FGFRL1, LINC00340, KCNH2, ANK1, ATXN2, NDRG21 and SLC16A11). Nearly all of the differentially methylated CpGs showed a propensity toward hypermethylation among clear-cell cases. Several loci methylation inversely correlated with tumor gene expression, most notably KCNH2 (HERG, a potassium channel) (P = 9.5 × 10(-7)), indicating epigenetic silencing. In addition, a predicted methylation class mainly represented by the clear-cell cases (20 clear cell out of 23 cases) had improved survival time. Although these analyses included only 30 clear-cell carcinomas, results suggest that loss of expression of KCNH2 (HERG) by methylation could be a good prognostic marker, given that overexpression of the potassium (K(+)) channel Eag family members promotes increased proliferation and results in poor prognosis. Validation in a bigger cohort of clear-cell tumors of the ovary is warranted.

Behavioural and functional characterization of Kv10.1 (Eag1) knockout mice

K_v10.1 (Eag1), member of the K_v10 family of voltage-gated potassium channels, is preferentially expressed in adult brain. The aim of the present study was to unravel the functional role of K_v10.1 in the brain by generating knockout mice, where the voltage sensor and pore region of K_v10.1 were removed to render non-functional proteins through deletion of exon 7 of the KCNH1 gene using the ‘3 Lox P strategy’. K_v10.1-deficient mice show no obvious alterations during embryogenesis and develop normally to adulthood; cortex, hippocampus and cerebellum appear anatomically normal. Other tests, including general health screen, sensorimotor functioning and gating, anxiety, social behaviour, learning and memory did not show any functional aberrations in K_v10.1 null mice. K_v10.1 null mice display mild hyperactivity and longer-lasting haloperidol-induced catalepsy, but there was no difference between genotypes in amphetamine sensitization and withdrawal, reactivity to apomorphine and haloperidol in the prepulse inhibition tests or to antidepressants in the haloperidol-induced catalepsy. Furthermore, electrical properties of K_v10.1 in cerebellar Purkinje cells did not show any difference between genotypes. Bearing in mind that K_v10.1 is overexpressed in over 70% of all human tumours and that its inhibition leads to a reduced tumour cell proliferation, the fact that deletion of K_v10.1 does not show a marked phenotype is a prerequisite for utilizing K_v10.1 blocking and/or reduction techniques, such as siRNA, to treat cancer.

Significance of HE4 estimation in comparison with CA125 in diagnosis of ovarian cancer and assessment of treatment response

BACKGROUND

Human epididymis protein 4 (HE4) is a novel and specific biomarker for ovarian cancer. The aim of this study is to evaluate a new tumor marker, HE4, in comparison with CA125 in diagnosis of epithelial ovarian cancer (EOC) and benign gynecological diseases.

METHODS

CA125 and HE4 serum levels were determined in 30 patients with epithelial ovarian cancer (21 serous, 6 endometrioid and 3 mucinous tumors), 20 patients with benign gynecological diseases (8 patients with ovarian cyst, 5 patients with endometriosis, 4 patients with fibroid and 3 patients with pelvic inflammatory disease) and 20 healthy women. CA125 and HE4 cut-offs were 35 U/ml and 150 pmol/l, respectively.

RESULTS

Serum HE4 and CA125 concentrations were significantly higher in the ovarian cancer patients compared with those seen in patients with benign disease or in the healthy controls (p = 0.001 and p < 0.001 respectively). In the receiver operating characteristic analysis (ROC), the area under the curve (AUC) values for HE4 was 0.96 (95% confidence interval, 0.9-1.0) and CA125 was 0.82 (95% confidence interval, 0.7-0.94). Compared to CA125, HE4 had higher sensitivity (90% vs. 83.3%), specificity (95% vs. 85%), PPV (93.1% vs. 80.7%) and NPV (92.7% vs. 87.2%), the combination of HE4 + CA125 the sensitivity and PPV reached 96.7% and 97% respectively.

CONCLUSION

Measuring serum HE4 concentrations along with CA125 concentrations may provide higher accuracy for detecting epithelial ovarian cancer.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1060413168685759.

Significance of HE4 estimation in comparison with CA125 in diagnosis of ovarian cancer and assessment of treatment response

BACKGROUND

Human epididymis protein 4 (HE4) is a novel and specific biomarker for ovarian cancer. The aim of this study is to evaluate a new tumor marker, HE4, in comparison with CA125 in diagnosis of epithelial ovarian cancer (EOC) and benign gynecological diseases.

METHODS

CA125 and HE4 serum levels were determined in 30 patients with epithelial ovarian cancer (21 serous, 6 endometrioid and 3 mucinous tumors), 20 patients with benign gynecological diseases (8 patients with ovarian cyst, 5 patients with endometriosis, 4 patients with fibroid and 3 patients with pelvic inflammatory disease) and 20 healthy women. CA125 and HE4 cut-offs were 35 U/ml and 150 pmol/l, respectively.

RESULTS

Serum HE4 and CA125 concentrations were significantly higher in the ovarian cancer patients compared with those seen in patients with benign disease or in the healthy controls (p = 0.001 and p < 0.001 respectively). In the receiver operating characteristic analysis (ROC), the area under the curve (AUC) values for HE4 was 0.96 (95% confidence interval, 0.9-1.0) and CA125 was 0.82 (95% confidence interval, 0.7-0.94). Compared to CA125, HE4 had higher sensitivity (90% vs. 83.3%), specificity (95% vs. 85%), PPV (93.1% vs. 80.7%) and NPV (92.7% vs. 87.2%), the combination of HE4 + CA125 the sensitivity and PPV reached 96.7% and 97% respectively.

CONCLUSION

Measuring serum HE4 concentrations along with CA125 concentrations may provide higher accuracy for detecting epithelial ovarian cancer.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1060413168685759.

Significance of HE4 estimation in comparison with CA125 in diagnosis of ovarian cancer and assessment of treatment response

BACKGROUND

Human epididymis protein 4 (HE4) is a novel and specific biomarker for ovarian cancer. The aim of this study is to evaluate a new tumor marker, HE4, in comparison with CA125 in diagnosis of epithelial ovarian cancer (EOC) and benign gynecological diseases.

METHODS

CA125 and HE4 serum levels were determined in 30 patients with epithelial ovarian cancer (21 serous, 6 endometrioid and 3 mucinous tumors), 20 patients with benign gynecological diseases (8 patients with ovarian cyst, 5 patients with endometriosis, 4 patients with fibroid and 3 patients with pelvic inflammatory disease) and 20 healthy women. CA125 and HE4 cut-offs were 35 U/ml and 150 pmol/l, respectively.

RESULTS

Serum HE4 and CA125 concentrations were significantly higher in the ovarian cancer patients compared with those seen in patients with benign disease or in the healthy controls (p = 0.001 and p < 0.001 respectively). In the receiver operating characteristic analysis (ROC), the area under the curve (AUC) values for HE4 was 0.96 (95% confidence interval, 0.9-1.0) and CA125 was 0.82 (95% confidence interval, 0.7-0.94). Compared to CA125, HE4 had higher sensitivity (90% vs. 83.3%), specificity (95% vs. 85%), PPV (93.1% vs. 80.7%) and NPV (92.7% vs. 87.2%), the combination of HE4 + CA125 the sensitivity and PPV reached 96.7% and 97% respectively.

CONCLUSION

Measuring serum HE4 concentrations along with CA125 concentrations may provide higher accuracy for detecting epithelial ovarian cancer.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1060413168685759.

hERG K+ Channels: Structure, Function, and Clinical Significance

The human ether-a-go-go related gene (hERG) encodes the pore-forming subunit of the rapid component of the delayed rectifier K+ channel, Kv11.1, which are expressed in the heart, various brain regions, smooth muscle cells, endocrine cells, and a wide range of tumor cell lines. However, it is the role that Kv11.1 channels play in the heart that has been best characterized, for two main reasons. First, it is the gene product involved in chromosome 7-associated long QT syndrome (LQTS), an inherited disorder associated with a markedly increased risk of ventricular arrhythmias and sudden cardiac death. Second, blockade of Kv11.1, by a wide range of prescription medications, causes drug-induced QT prolongation with an increase in risk of sudden cardiac arrest. In the first part of this review, the properties of Kv11.1 channels, including biogenesis, trafficking, gating, and pharmacology are discussed, while the second part focuses on the pathophysiology of Kv11.1 channels.

Eag1 channels as potential cancer biomarkers

Cancer is a leading cause of death worldwide. New early tumor markers are needed to treat the disease at curable stages. In addition, new therapeutic targets are required to treat patients not responding to available treatments. Ion channels play major roles in health and disease, including cancer. Actually, several ion channels have been suggested as potential tumor markers and therapeutic targets for different types of malignancies. One of most studied ion channels in cancer is the voltage-gated potassium channel Eag1 (ether à go-go 1), which has a high potential to be used as a cancer biomarker. Eag1 is expressed in most human tumors, in contrast to its restricted distribution in healthy tissues. Several findings suggest Eag1 as a potential early marker for cervical, colon, and breast cancer. In addition, because Eag1 amplification/expression is associated with poor survival in leukemia, colon and ovarian cancer patients, it has also been proposed as a prognosis marker. Moreover, inhibition of either expression or activity of Eag1 leads to reduced proliferation of cancer cells, making Eag1 a potential anticancer target. Using Eag1 in cancer detection programs could help to reduce mortality from this disease.