Clic1 plays a role in mouse hepatocarcinoma via modulating Annexin A7 and Gelsolin in vitro and in vivo

CLIC1-mediated autophagy confers resistance to DDP in gastric cancer

Gastric cancer has been a constant concern to researchers as one of the most common malignant tumors worldwide. The treatment options for gastric cancer include surgery, chemotherapy and traditional Chinese medicine. Chemotherapy is an effective treatment for patients with advanced gastric cancer. Cisplatin (DDP) has been approved as a critical chemotherapy drug to treat various kinds of solid tumors. Although DDP is an effective chemotherapeutic agent, many patients develop drug resistance during treatment, which has become a severe problem in clinical chemotherapy. This study aims to investigate the mechanism of DDP resistance in gastric cancer. The results show that intracellular chloride channel 1 (CLIC1) expression was increased in AGS/DDP and MKN28/DDP, and as compared to the parental cells, autophagy was activated. In addition, the sensitivity of gastric cancer cells to DDP was decreased compared to the control group, and autophagy increased after overexpression of CLIC1. On the contrary, gastric cancer cells were more sensitive to cisplatin after transfection of CLIC1siRNA or treatment with autophagy inhibitors. These experiments suggest that CLIC1 could alter the sensitivity of gastric cancer cells to DDP by activating autophagy. Overall, the results of this study recommend a novel mechanism of DDP resistance in gastric cancer.

The targeting imaging and treatment capacity of gelsolin-targeted and paclitaxel-loaded PLGA nanoparticles in vitro and in vivo

As a vital sign of carcinomas, lymph node metastasis is closely related to poor prognosis due to a lack of identification and effective treatment in the early stage. Nanoscale contrast agents targeting specific tumor antigens are expected to identify tumor metastasis in the early stage and achieve precise treatment. As a biomarker in the early stage of tumor invasion and metastasis, gelsolin (GSN) might be a promising molecular target to identify and screen tumor metastasis through the lymphatic system. Therefore, GSN-targeted paclitaxel-loaded poly(lactic-co-glycolic acid) nanoparticles (GSN-PTX-PLGA NPs) were prepared, and their physicochemical properties, encapsulation efficiency, drug loading, and dissolution were determined. Besides, uptake experiments and the fluorescent imaging system were used to evaluate their targeting capability. The targeting imaging and treatment capacity were also assessed by experiments in vitro and in vivo. The diameter of the GSN-PTX-PLGA NPs was 328.59 ± 3.82 nm. Hca-F cells with GSN-PLGA NPs showed stronger green fluorescence than Hca-P cells. DiI-labeled GSN-PLGA NPs in tumor-bearing mice and isolated organs exhibited more prominent fluorescence aggregation. The imaging of GSN-PLGA NPs was satisfactory in vitro, and the echo intensity gradually increased with increasing concentrations of GSN-PLGA NPs. After treatment with GSN-PTX-PLGA NPs, there was an obvious decrease in tumor volume and lymph node metastasis rate compared to the other groups (p < 0.05). In conclusion, GSN-PTX-PLGA NPs have a remarkable targeting capacity in vivo and in vitro, and they effectively inhibit tumor growth and lymph node metastasis in vivo.

Zn2+ triggered two-step mechanism of CLIC1 membrane insertion and activation into chloride channels

The chloride intracellular channel (CLIC) protein family displays the unique feature of altering its structure from a soluble form to a membrane-bound chloride channel. CLIC1, a member of this family, is found in the cytoplasm or in internal and plasma membranes, with membrane relocalisation linked to endothelial disfunction, tumour proliferation and metastasis. The molecular switch promoting CLIC1 activation remains under investigation. Here, cellular Cl⁻ efflux assays and immunofluorescence microscopy studies have identified intracellular Zn²⁺ release as the trigger for CLIC1 activation and membrane insertion. Biophysical assays confirmed specific binding to Zn²⁺, inducing membrane association and enhancing Cl⁻ efflux in a pH-dependent manner. Together, our results identify a two-step mechanism with Zn²⁺ binding as the molecular switch promoting CLIC1 membrane insertion, followed by pH-mediated activation of Cl⁻ efflux.

Summary: Identification of a two-step mechanism of CLIC1 membrane insertion based on Zn²⁺ binding and pH activation of Cl⁻ efflux.

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.

Identification of chloride intracellular channels as prognostic factors correlated with immune infiltration in hepatocellular carcinoma using bioinformatics analysis

ABSTRACT

Chloride intracellular channel (CLIC) proteins are novel Cl-channels with 6 family members (CLIC1-6) that are known to play crucial roles in multiple physiological functions, such as neurological, cardiovascular, pulmonary, and auditory functions, and in various malignancies, including hepatocellular carcinoma (HCC). However, considerable challenges exist in identifying appropriate CLICs as therapeutic target molecules and prognostic biomarkers for HCC because the transformation of soluble or integral membrane protein forms, and specific pharmacological agents (agonists and antagonists) for distinct CLICs remains enigmatic.To address this issue and the possible molecular basis and the signaling networks activated by CLICs in HCC, we examined the transcriptional, promoter methylation, DNA mutation, survival, and immune infiltration data of CLICs in patients with HCC using the ONCOMINE, UALCAN, GEPIA, cBioPortal, and TIMER databases.The data showed that the expression levels of CLIC family members were differed between tumor and normal tissues. High expression levels of CLIC1 and CLIC3 were associated with advanced cancer stage in HCC patients. Low CLIC1 expression was associated with a better overall survival (OS). The DNA methylation levels of the CLIC1-3 and CLIC5-6 promoters in tumor tissue with HCC were significantly lower in HCC tissues than in normal tissues. Patients with CLIC1 alterations had a shorter OS than patients with unaltered CLIC1. Moreover, the expression levels of CLICs correlated with the infiltration of 6 different immune cells (B cells, CD4+ T cells, CD8+ T cells, neutrophils, macrophages, and dendritic cells).These results indicate that the increased mRNA expression and decreased promoter DNA methylation level of CLICs may play crucial roles in HCC tumorigenesis. The expression of CLIC family members was significantly correlated with the tumor immune status. High CLIC1 and CLIC3 expression levels could serve as biomarkers for identifying advanced-stage HCC. Moreover, a CLIC1 mutation rate of 18% was also observed and CLIC1 genetic alterations were significantly associated with lower OS in HCC patients.

Chloride intracellular channels as novel biomarkers for digestive system tumors (Review)

Digestive system malignant tumors are common tumors, and the traditional treatment methods for these tumors include surgical resection, radiotherapy, chemotherapy, and molecularly targeted drugs. However, diagnosis remains challenging, and the early detection of postoperative recurrence is complicated. Therefore, it is necessary to explore novel biomarkers to facilitate clinical diagnosis and treatment. Accumulating evidence supports the crucial role of chloride channels in the development of multiple types of cancers. Given that chloride channels are widely expressed and involved in cell proliferation, apoptosis and cell cycle, among other processes, they may serve as a promising diagnostic and therapeutic target. Chloride intracellular channels (CLICs) are a class of chloride channels that are upregulated or downregulated in certain types of cancer. Furthermore, in certain cases, during cell cycle progression, the localization and function of the cytosolic form of the transmembrane proteins of CLICs are also altered, which may provide a key target for cancer therapy. The aim of the present review was to focus on CLICs as biomarkers for digestive system tumors.

The protective effect of tanshinone IIa on endothelial cells: a generalist among clinical therapeutics

INTRODUCTION

Tanshinone IIa (TSA) has been approved to treat cardiovascular diseases by the China State Food and Drug Administration. TSA has exhibited a variety of pharmacological effects, including vasodilator, antioxidant, anti-inflammatory, and anti-tumor properties. Endothelial cells play an important physiological role in vascular homeostasis and control inflammation, coagulation, and thrombosis. Accumulating studies have shown that TSA can improve endothelial function through various pathways.

AREAS COVERED

The PubMed database was reviewed for relevant papers published up to 2020. This review summarizes the current clinical and pharmaceutical studies to provide a systemic overview of the pharmacological and therapeutic effects of TSA on endothelial cells.

EXPERT OPINION

TSA is a representative monomeric compound extracted from Danshen and it exhibits significant pharmacological and therapeutic properties to improve endothelial cell function, including alleviating oxidative stress, attenuating inflammatory injury, modulating ion channels and so on. TSA represents a spectrum of agents that are extracted from plants and can restore the endothelial function to establish the beneficial and harmless molecular therapeutics. This also suggests the possible detection of endothelial cells for very early diagnosis of diseases. In future, precise therapeutic methods will be developed to repair endothelial cells injury and recover endothelial dysfunction.

The potential mechanism of action of Sorcin and its interacting proteins

Sorcin (Soluble resistance-related calcium binding protein) is a calcium binding oncoprotein. Sorcin is overexpressed in several human tumors and cancer cells lines which confers multidrug resistance (MDR) to these cells. This review summarizes the biochemical functions of Sorcin which includes modulation of calcium homeostasis, apoptosis, and cancer metastasis. Sorcin is involved in various biological processes by interacting with other proteins, such as p-glycoprotein, programmed cell death protein 6, tumor necrosis factor receptor-associated protein 1, Annexin A7, polo-like kinase 1, HCV nonstructural 5A, signal transducer and activator of transcription 3, presenilin 2, α-synuclein, Ca²⁺-release channel and others. A deeper look into the function and interacting partners of Sorcin sheds more light on the possible effects of its physical activity and more elaborately, exploring the role of Sorcin in future research prospects.

Exosome-mediated transfer of CLIC1 contributes to the vincristine-resistance in gastric cancer

Our previous study shows that high Chloride intracellular channel 1 (CLIC1) expression can efficiently enhance invasion and migration of gastric cancer (GC) cells in vitro. Growing evidences have found that exosomes are involved in chemotherapy resistance in several cancers including GC. We aimed to evaluate the effect of the exosome-mediated transfer of CLIC1 in the vincristine-resistance of GC. The effect of exosome-mediated transfer of CLIC1 on the development of resistance to vincristine in GC cell line SGC-7901 and the potential underlying mechanisms were investigated by Cell Counting Kit-8 (CCK8), RT-PCR, and Western blotting. Exosomes were isolated from cell supernatants by differential ultracentrifugation. Comparing with SGC-7901, the expression level of CLIC1 is higher in vincristine‑resistant cell line SGC-7901/VCR (P < 0.05). After silencing the expression of CLIC1 by RNA interference, the half inhibition concentration (IC50) to vincristine decreased significantly in SGC-7901/VCR, and the expression of CLIC1 decreased significantly in exosomes from SGC-7901/VCR. After 48 h co-culturing with exosomes from SGC-7901/VCR, the IC50 to vincristine in SGC-7901 increased significantly, and the expression of CLIC1, P-gp, and Bcl-2 were significantly up-regulated. CLIC1 was closely associated with the resistance to vincristine in GC, and exosome-mediated transfer of CLIC1 could induce the development of resistance to vincristine in vitro. The possible mechanism was related to up-regulated P-gp and Bcl-2. However, in vivo study was needed to confirm the results in future.

Expression of CLIC1 as a potential biomarker for oral squamous cell carcinoma: a preliminary study

Purpose

CLIC1, a member of the highly conserved class ion-channel protein family, is frequently upregulated in multiple human malignancies and has been demonstrated to play a critical role in cell proliferation, apoptosis, and invasion. However, limited is known about its expression, biological functions, and action mechanism in oral malignancies. We aimed to evaluate whether CLIC1 could be a biomarker for oral squamous cell carcinoma (OSCC).

Methods

Immunohistochemistry was used to analyze the expression of CLIC1 in tissue. CLIC1 protein and mRNA were measured through Western immunoblotting and quantitative real-time PCR. CLIC1 protein expression in plasma was detected via ELISA. A total of 72 OSCC specimens were recruited in this study for evaluation of correlations of CLIC1 with clinicopathological features and survival.

Results

CLIC1 was significantly overexpressed in tissue and plasma of OSCC patients. It was found that upregulated CLIC1 was distinctly correlated with histological grade, TNM stage, and tumor size. Meanwhile, Kaplan–Meier survival analysis showed that OSCC patients with high CLIC1 expression had remarkably poorer overall survival rate than those with low CLIC1 expression. Multivariate Cox regression analysis revealed that CLIC1 was the independent prognostic factor for overall survival rate of OSCC patients. In addition, Pearson correlation analysis showed that CLIC1 was associated with multiple tumor-associated genes.

Conclusion

These results indicated that CLIC1 acts as a molecular target in OSCC and may present a novel diagnostic marker and therapeutic target for OSCC.

High co-expression of the SDF1/CXCR4 axis in hepatocarcinoma cells is regulated by AnnexinA7 in vitro and in vivo

BACKGROUND

SDF1/CXCR4 and AnnexinA7 play important roles in many physiological and pathological conditions, but the molecular association between them in cancer cells has not been studied thus far.

METHODS

The expression changes of SDF1/CXCR4 were detected by gene transcriptome sequencing, qRT-PCR, Western blotting, cytoimmunofluorescence and immunohistochemistry in mouse hepatocarcinoma F/P cells, AnnexinA7 downregulated expression F (FA7DOWN) cells, AnnexinA7 overexpression P (PA7UP) cells, AnnexinA7 unrelated sequence F (FSHUS) cells, empty vector P (PNCEV) cells and normal liver cells in vitro and in vivo.

RESULTS

SDF1 and CXCR4 were co-expressed in hepatocarcinoma cells. SDF1 was localized mainly in the cytoplasm of cells, while CXCR4 was mainly localized in the cell membrane. Both in vitro and in vivo, expression levels of SDF1/CXCR4 in F and P cells were higher than in normal liver cells, and expression levels of SDF1/CXCR4 in F cells with high lymphatic metastatic potential were higher than those in P cells with low lymphatic metastatic potential. Expression of SDF1 was higher than that of CXCR4 in P cells and normal liver cells, while expression of CXCR4 was higher than that of SDF1 in F cells. Expression levels of SDF1/CXCR4 were completely consistent with AnnexinA7 regulation. After the AnnexinA7 gene was downregulated or upregulated, expression levels of SDF1/CXCR4 in FA7DOWN/PA7UP cells were lower or higher than those in FSHUS/PNCEV cells. Furthermore, CXCR4 was more sensitively modulated by AnnexinA7 regulation than SDF1.

CONCLUSIONS

High co-expression of SDF1/CXCR4 is a molecular characteristic of hepatocarcinoma cells, especially those with high lymphatic metastatic potential. AnnexinA7 positively regulates expression levels of SDF1/CXCR4, in particular CXCR4, and AnnexinA7 is a functional regulator of SDF1/CXCR4.

Hepatoprotective effects of capping protein gelsolin against hyperoxia-induced hepatotoxicity, oxidative stress and DNA damage in neonatal rats

Tissues and organs get exposed to high oxygen (O₂) supply in hyperoxia conditions. The goal of this research was to investigate the protective effect of actin binding protein gelsolin on hyperoxia-induced hepatotoxicity through histopathology and measurement of oxidative stress parameters and DNA damage in a neonatal Wistar albino rats. The pups were randomly separated to four equal groups such as: normoxia control group (NC), normoxia plus gelsolin group (NG, 10 ng/kg bw/day gelsolin), hyperoxia (≥85% O₂) group (HC), hyperoxia plus gelsolin group (HG, ≥85% O₂; 10 ng/kg bw/day gelsolin). Histopathological changes of pups in hyperoxia condition were revealed in the form of severe leukocyte infiltration, vascular congestion, necrosis, vacuolar degeneration, binucleated hepatocytes and hemorrhage in the liver tissue. SOD, CAT, GPx and GST activities decreased and MDA level increased in the hyperoxia-induced group in liver tissue (P < 0.05). Tail DNA%, tail length and moment indicating DNA damage statistically increased in hyperoxia treatment groups when compared to controls. Treatment of rats with hyperoxia plus gelsolin prevented hyperoxia-induced changes in tissue structure, antioxidant enzyme activities and MDA level, mean tail DNA% and length. Based on these findings, gelsolin restored these changing to near normal levels but it does not protect completely in the hyperoxia conditions.

Tanshinone IIA Sodium sulfonate regulates antioxidant system, inflammation, and endothelial dysfunction in atherosclerosis by downregulation of CLIC1

BACKGROUND

Tanshinone IIA Sodium sulfonate (STS) is clinically used for treating cardiovascular diseases in Traditional Chinese Medicine due to its antioxidation and anti-inflammation activities. Intracellular chloride channel 1 (CLIC1) participates in the regulation of oxidative stress and inflammation. This study investigates whether CLIC1 mediates the cardioprotective effects of STS.

METHODS

STS were used to treat atherosclerosis (AS) induced by feeding Apolipoprotein E-deficient (ApoE^-/-) mice with a high-fat, cholesterol-rich diet. In addition, normal and CLIC1^-/- human umbilical vein endothelial cells were treated with STS after exposure to H₂O₂ for 12h. The oxidative status was determined by analyzing reactive oxygen species(ROS) and malondialdehyde (MDA) levels. ELISA, qRT-PCR and Western blot were used to determine the levels of TNF-α, IL-6, ICAM-1 and VCAM-1. CLIC1 cellular localization was examined by immunofluorescence. Chloride ion concentration was detected with chloride ion quenchers (MQAE).

RESULTS

STS treatment decreased atherosclerotic lesion area by 3.5 times (P = 0.001) in vivo. Meanwhile, STS reduced MDA production (13.6%, P = 0.008), increased SOD activity (113.6%, P = 0.008), decreased TNF-α (38.6%, P = 0.008) and IL-6 (43.0%, P = 0.03) levels, and downregulated the expression of CLIC1, ICAM-1, and VCAM-1 in the atherosclerotic mice. The dose-dependent anti-oxidative and anti-inflammatory effects of STS were further confirmed in vitro. Furthermore, CLIC1 depletion abolished the STS-mediated decrease of ROS and MDA production in HUVEC cells. Additionally, STS inhibited both CLIC1 membrane translocation and chloride ion concentration.

CONCLUSION

The anti-oxidant, and anti-inflammation properties of STS in preventing AS is mediated by its inhibition of CLIC1 expression and membrane translocation.

Ion Channels and Oxidative Stress as a Potential Link for the Diagnosis or Treatment of Liver Diseases

Oxidative stress results from a disturbed balance between oxidation and antioxidant systems. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) may be either harmful or beneficial to the cells. Ion channels are transmembrane proteins that participate in a large variety of cellular functions and have been implicated in the development of a variety of diseases. A significant amount of the available drugs in the market targets ion channels. These proteins have sulfhydryl groups of cysteine and methionine residues in their structure that can be targeted by ROS and RNS altering channel function including gating and conducting properties, as well as the corresponding signaling pathways associated. The regulation of ion channels by ROS has been suggested to be associated with some pathological conditions including liver diseases. This review focuses on understanding the role and the potential association of ion channels and oxidative stress in liver diseases including fibrosis, alcoholic liver disease, and cancer. The potential association between ion channels and oxidative stress conditions could be used to develop new treatments for major liver diseases.