Adseverin: a novel cisplatin-resistant marker in the human bladder cancer cell line HT1376 identified by quantitative proteomic analysis

Gelsolin, an Actin-Binding Protein: Bioinformatic Analysis and Functional Significance in Urothelial Bladder Carcinoma

The involvement of the actin-regulatory protein, gelsolin (GSN), in neoplastic transformation has been reported in different cancers including bladder cancer. However, the exact mechanism by which GSN influences bladder cancer development is not well understood. Here, we sought to reveal the functional significance of GSN in bladder cancer by undertaking a comprehensive bioinformatic analysis of TCGA datasets and through the assessment of multiple biological functions. GSN expression was knocked down in bladder cancer cell lines with two siRNA isoforms targeting GSN. Proliferation, migration, cell cycle and apoptosis assays were carried out. GSN expression, enrichment analysis, protein-protein interaction and immune infiltration analysis were verified through online TCGA tools. The data indicated that GSN expression is associated with bladder cancer proliferation, migration and enhanced cell apoptosis through regulation of NF-κB expression. GSN expression correlated with various inflammatory cells and may influence the immunity of the tumor microenvironment. Computational analysis identified several interacting partners which are associated with cancer progression and patient outcome. The present results demonstrate that GSN plays an important role in bladder cancer pathogenesis and may serve as a potential biomarker and therapeutic target for cancer therapy.

Bioprosthetic Valve Deterioration: Accumulation of Circulating Proteins and Macrophages in the Valve Interstitium

Histologic evaluations revealed excessive accumulations of macrophages and absence of fibroblastic interstitial cells in explanted bioprosthetic valves. Comprehensive gene and protein expression analysis and histology unveiled an accumulation of fibrinogen and plasminogen, an activator of infiltrated macrophages, from degenerated valve surfaces in the interstitial spaces. These pathologies were completely reproduced in a goat model replaced with an autologous pericardium-derived aortic valve. Further preclinical animal experiments using goats demonstrated that preventing infiltration of macrophages and circulating proteins by increasing collagen density and leaflet strength is an effective treatment option.

Targeting AVIL, a New Cytoskeleton Regulator in Glioblastoma

Glioblastoma (GBM) is the most common adult neural malignancy and the deadliest. The standard of care is optimal, safe, cytoreductive surgery followed by combined radiation therapy and alkylating chemotherapy with temozolomide. Recurrence is common and therapeutic options in the recurrent setting are limited. The dismal prognosis of GBM has led to novel treatments being a serious roadblock in the field, with most new treatments failing to show efficacy. Targeted therapies have shown some success in many cancers, but GBM remains one of the most difficult to treat, especially in recurrence. New chemotherapeutic directions need to be explored, possibly expanding the targeted chemotherapy spectrum in previously unforeseen ways. In this perspective paper, we will explain why AVIL, an actin-binding protein recently found to be overexpressed in GBM and a driving force for GBM, could prove versatile in the fight against cancer. By looking at AVIL and its potential to regulate FOXM1 and LIN28B, we will be able to highlight a way to improve outcomes for GBM patients who normally have very little hope.

Cellular Interactome of Mitochondrial Voltage-Dependent Anion Channels: Oligomerization and Channel (Mis)Regulation

Voltage-dependent anion channels (VDACs) of the outer mitochondrial membrane are known conventionally as metabolite flux proteins. However, research findings in the past decade have revealed the multifaceted regulatory roles of VDACs, from governing cellular physiology and mitochondria-mediated apoptosis to directly regulating debilitating cancers and neurodegenerative diseases. VDACs achieve these diverse functions by establishing isoform-dependent stereospecific interactomes in the cell with the cytosolic constituents and endoplasmic reticulum complexes, and the machinery of the mitochondrial compartments. VDACs are now increasingly recognized as regulatory hubs of the cell. Not surprisingly, even the transient misregulation of VDACs results directly in mitochondrial dysfunction. Additionally, human VDACs are now implicated in interaction with aggregation-prone cytosolic proteins, including Aβ, tau, and α-synuclein, contributing directly to the onset of Alzheimer's and Parkinson's diseases. Deducing the interaction dynamics and mechanisms can lead to VDAC-targeted peptide-based therapeutics that can alleviate neurodegenerative states. This review succinctly presents the latest findings of the VDAC interactome, and the mode(s) of VDAC-dependent regulation of biochemical physiology. We also discuss the relevance of VDACs in pathophysiological states and aggregation-associated diseases and address how VDACs will facilitate the development of next-generation precision medicines.

MiR-301a-5p/SCIN promotes gastric cancer progression via regulating STAT3 and NF-κB signaling

Objective: Gastric cancer (GC) is a type of highly malignant cancer. Although the diagnostic and therapeutic methods are innovating, the outcome of GC patients is still poor. Therefore, our research was carried out to explore potential molecular mechanism in the diagnosis of GC.

Materials and methods: Bioinformatics analyses were used to obtain microRNA and target mRNA of interest. The expression level of miR-301a-5p and Scinderin (SCIN) mRNA were detected by quantitative real-time PCR (qRT-PCR). Western blot assay was used to investigate SCIN protein level. Cell Counting Kit-8 assay (CCK-8) and colony formation assay were used to investigate cell proliferation ability. Transwell assay was employed to examine cell motility. The interaction between miR-301a-5p and SCIN mRNA was verified by dual-luciferase reporter assay.

Results: The qRT-PCR analysis revealed that the expression of miR-301a-5p was higher in gastric cancer tissues than para-cancer tissues (P<0.05). Cox regression analysis showed upregulated miR-301a-5p was associated with larger tumor size (P=0.036) and more advanced TNM stage (P=0.048). The Kaplan-Meier analysis showed a correlation between increased miR-301a-5p expression and shorter overall survival (OS)(P=0.018). By using bioinformatic analysis, SCIN was predicted as one of the targets of miR-301a-5p. Overexpressing miR-301a-5p promoted proliferation and motility of GC cells while knockdown of SCIN exhibited the same performance. Further, we verified the alteration of miR-301a-5p and SCIN expression level could affect the epithelial-mesenchymal transition (EMT) progression on GC cells via STAT3 and NF-κB signaling.

Conclusion: Highly expressed miR-301a-5p was associated with aggressiveness of GC. Upregulation of miR-301a-5p promoted malignant phenotype of GC by targeting SCIN. The present results indicated miR-301a-5p might be a promising molecule in the prognosis of GC.

VDAC1 at the Intersection of Cell Metabolism, Apoptosis, and Diseases

The voltage-dependent anion channel 1 (VDAC1) protein, is an important regulator of mitochondrial function, and serves as a mitochondrial gatekeeper, with responsibility for cellular fate. In addition to control over energy sources and metabolism, the protein also regulates epigenomic elements and apoptosis via mediating the release of apoptotic proteins from the mitochondria. Apoptotic and pathological conditions, as well as certain viruses, induce cell death by inducing VDAC1 overexpression leading to oligomerization, and the formation of a large channel within the VDAC1 homo-oligomer. This then permits the release of pro-apoptotic proteins from the mitochondria and subsequent apoptosis. Mitochondrial DNA can also be released through this channel, which triggers type-Ι interferon responses. VDAC1 also participates in endoplasmic reticulum (ER)-mitochondria cross-talk, and in the regulation of autophagy, and inflammation. Its location in the outer mitochondrial membrane, makes VDAC1 ideally placed to interact with over 100 proteins, and to orchestrate the interaction of mitochondrial and cellular activities through a number of signaling pathways. Here, we provide insights into the multiple functions of VDAC1 and describe its involvement in several diseases, which demonstrate the potential of this protein as a druggable target in a wide variety of pathologies, including cancer.

Aberrant Scinderin Expression Correlates With Liver Metastasis and Poor Prognosis in Colorectal Cancer

Many genes and mutations have been reported for colorectal cancer (CRC); however, very few have been associated with colorectal cancer liver metastasis (CRLM). We performed gene expression profiling experiments to identify genetic markers for CRLM and elucidate the molecular mechanisms. Microarray experiments were performed on CRC primary tumor samples with or without liver metastasis (LM) using the Affymetrix U133 plus 2.0 GeneChip Array. A new identified gene-scinderin (SCIN) was overexpressed with synchronous LM at both the RNA level evaluated with quantitative real-time PCR and protein level evaluated with immunohistochemistry and also with short overall survival analyzed with Kaplan-Meier method. With multivariate analysis indicated that SCIN served as an independent poor prognostic predictor for CRC patients. Disease-free survival was also significantly lower in SCIN overexpressing CRC patients with metachronous LM. In addition, SCIN knockdown significantly reduced cell proliferation, induced cell cycle arrest, and promoted the expression of some cell cycle apoptosis-related protein. Moreover, the DIAPH1, STAT3, CDK2, CDK4, and EGFR levels were downregulated, whereas CDKN2B and COL4A1 were upregulated in DLD-1-shSCIN cells by microarray analysis compared with DLD-1 shCon cells. These findings revealed that SCIN may serve as an important predictor of CRLM and poor outcome for CRC patients. SCIN may be a potential therapeutic target in human CRC. However, translation of its roles into clinical practice will require further investigation and additional experimental validation.

Protein-protein interaction networks as a new perspective to evaluate distinct functional roles of voltage-dependent anion channel isoforms

Voltage-dependent anion channels (VDACs) are a family of three mitochondrial porins and the most abundant integral membrane proteins of the mitochondrial outer membrane (MOM). VDACs are known to be involved in metabolite/ion transport across the MOM and in many cellular processes ranging from mitochondria-mediated apoptosis to the control of energy metabolism, by interacting with cytosolic, mitochondrial and cytoskeletal proteins and other membrane channels. Despite redundancy and compensatory mechanisms among VDAC isoforms, they display not only different channel properties and protein expression levels, but also distinct protein partners. Here, we review the known protein interactions for each VDAC isoform in order to shed light on their peculiar roles in physiological and pathological conditions. As proteins associated with the MOM, VDAC opening/closure as a metabolic checkpoint is regulated by protein-protein interactions, and is of pharmacological interest in pathological conditions such as cancer. The interactions involving VDAC1 have been characterized more in depth than those involving VDAC2 and VDAC3. Nevertheless, the so far explored VDAC-protein interactions for each isoform show that VDAC1 is mainly involved in the maintenance of cellular homeostasis and in pro-apoptotic processes, whereas VDAC2 displays an anti-apoptotic role. Despite there being limited information on VDAC3, this isoform could contribute to mitochondrial protein quality control and act as a marker of oxidative status. In pathological conditions, namely neurodegenerative and cardiovascular diseases, both VDAC1 and VDAC2 establish abnormal interactions aimed to counteract the mitochondrial dysfunction which contributes to end-organ damage.

Scinderin is a novel transcriptional target of BRMS1 involved in regulation of hepatocellular carcinoma cell apoptosis

Tumor metastasis suppressor factor BRMS1 can regulate the metastasis of breast cancer and other tumors. Here we report scinderin (SCIN) as a novel transcriptional target of BRMS1. SCIN protein belongs to the cytoskeletal gelsolin protein superfamily and its involvement in tumorigenesis remains largely illusive. An inverse correlation between the expression levels of BRMS1 and SCIN was observed in hepatocellular carcinoma (HCC) cells and tissues. On the molecular level, BRMS1 binds to SCIN promoter and exerts a suppressive role in regulating SCIN transcription. FACS analysis and caspase 9 immunoblot reveal that knockdown of SCIN expression can sensitize HCC cells to chemotherapeutic drugs, leading to suppression of tumor growth in vivo. Consistently, overexpression of SCIN protects cells from apoptotic death, contributing to increased xenografted HCC cell growth. In summary, our study reveals SCIN as a functional apoptosis regulator as well as a novel target of BRMS1 during HCC tumorigenesis. Inhibition of SCIN might bring a potential cancer therapy approach.

A proteomic analysis of an in vitro knock-out of miR-200c

Loss of miR-200c is correlated to advanced cancer-subtypes due to increased EMT and decreased treatment efficacy by chemotherapeutics. As miRNAs regulate a multitude of targets, the analysis of differentially expressed proteins upon a genomic knock-out (KO) is of interest. In this study, we generated a TALENs KO of miR-200c in MCF7 breast cancer cells, excluded its compensation by family-members and evaluated the impact on the proteome by analyzing three individual KO-clones. We identified 26 key proteins and a variety of enrichments in metabolic and cytoskeletal pathways. In six of these targets (AGR2, FLNA/B, ALDH7A1, SCIN, GSTM3) the differential expression was additionally detected at mRNA level. Together, these alterations in protein abundance accounted for the observed biological phenotypes, i.e. increased migration and chemoresistance and altered metabolism, found in the miR-200c-KO clones. These findings provide novel insights into miR-200c and pave the way for further studies.

VDAC1 functions in Ca2+ homeostasis and cell life and death in health and disease

In the outer mitochondrial membrane (OMM), the voltage-dependent anion channel 1 (VDAC1) serves as a mitochondrial gatekeeper, controlling the metabolic and energy cross-talk between mitochondria and the rest of the cell. VDAC1 also functions in cellular Ca²⁺ homeostasis by transporting Ca²⁺ in and out of mitochondria. VDAC1 has also been recognized as a key protein in mitochondria-mediated apoptosis, contributing to the release of apoptotic proteins located in the inter-membranal space (IMS) and regulating apoptosis via association with pro- and anti-apoptotic members of the Bcl-2 family of proteins and hexokinase. VDAC1 is highly Ca²⁺-permeable, transporting Ca²⁺ to the IMS and thus modulating Ca²⁺ access to Ca²⁺ transporters in the inner mitochondrial membrane. Intra-mitochondrial Ca²⁺ controls energy metabolism via modulating critical enzymes in the tricarboxylic acid cycle and in fatty acid oxidation. Ca²⁺ also determines cell sensitivity to apoptotic stimuli and promotes the release of pro-apoptotic proteins. However, the precise mechanism by which intracellular Ca²⁺ mediates apoptosis is not known. Here, the roles of VDAC1 in mitochondrial Ca²⁺ homeostasis are presented while emphasizing a new proposed mechanism for the mode of action of pro-apoptotic drugs. This view, proposing that Ca²⁺-dependent enhancement of VDAC1 expression levels is a major mechanism by which apoptotic stimuli induce apoptosis, position VDAC1 oligomerization at a molecular focal point in apoptosis regulation. The interactions of VDAC1 with many proteins involved in Ca²⁺ homeostasis or regulated by Ca²⁺, as well as VDAC-mediated control of cell life and death and the association of VDAC with disease, are also presented.

Scinderin promotes the invasion and metastasis of gastric cancer cells and predicts the outcome of patients

Invasion and metastasis are major malignant characteristics of human gastric cancer (GC), but the underlying molecular mechanisms are poorly understood. Recent studies have shown that scinderin (SCIN), an actin severing and capping protein that regulates the actin cytoskeleton, is involved in the proliferation and migration of certain cancer cells. Accordingly, this study aimed to investigate the potential role of SCIN in the invasion and metastasis of human GC cells and to evaluate its prognostic value for GC patients. We found that high levels of SCIN expression in GC tumors were correlated with poor overall survival of patients. Silencing of SCIN effectively suppressed the migratory and invasive capabilities of human GC cells in vitro and tumorigenicity and metastasis in vivo. Furthermore, knockdown of SCIN markedly inhibited the formation of filopodia, decreasing GC cell migration and the expression of Cdc42, an important regulator of filopodia by GC cells. These findings suggest that SCIN may be a novel prognostic marker and a potential therapeutic target in human GC.

Calcium-controlled conformational choreography in the N-terminal half of adseverin

Adseverin is a member of the calcium-regulated gelsolin superfamily of actin-binding proteins. Here we report the crystal structure of the calcium-free N-terminal half of adseverin (iA1-A3) and the Ca(2+)-bound structure of A3, which reveal structural similarities and differences with gelsolin. Solution small-angle X-ray scattering combined with ensemble optimization revealed a dynamic Ca(2+)-dependent equilibrium between inactive, intermediate and active conformations. Increasing calcium concentrations progressively shift this equilibrium from a main population of inactive conformation to the active form. Molecular dynamics simulations of iA1-A3 provided insights into Ca(2+)-induced destabilization, implicating a critical role for the A2 type II calcium-binding site and the A2A3 linker in the activation process. Finally, mutations that disrupt the A1/A3 interface increase Ca(2+)-independent F-actin severing by A1-A3, albeit at a lower efficiency than observed for gelsolin domains G1-G3. Together, these data address the calcium dependency of A1-A3 activity in relation to the calcium-independent activity of G1-G3.

Biomarker in Cisplatin-Based Chemotherapy for Urinary Bladder Cancer

The treatment of metastasized bladder cancer has been evolving during recent years. Cisplatin based chemotherapy combinations are still gold standard in the treatment of advanced and metastasized bladder cancer. But new therapies are approaching. Based to this fact biological markers will become more important for decisions in bladder cancer treatment. A systematic MEDLINE search of the key words "cisplatin", "bladder cancer", "DNA marker", "protein marker", "methylation biomarker", "predictive marker", "prognostic marker" has been made. This review aims to highlight the most relevant clinical and experimental studies investigating markers for metastasized transitional carcinoma of the urothelium treated by cisplatin based regimens.

The mitochondrial voltage-dependent anion channel 1 in tumor cells

VDAC1 is found at the crossroads of metabolic and survival pathways. VDAC1 controls metabolic cross-talk between mitochondria and the rest of the cell by allowing the influx and efflux of metabolites, ions, nucleotides, Ca2+ and more. The location of VDAC1 at the outer mitochondrial membrane also enables its interaction with proteins that mediate and regulate the integration of mitochondrial functions with cellular activities. As a transporter of metabolites, VDAC1 contributes to the metabolic phenotype of cancer cells. Indeed, this protein is over-expressed in many cancer types, and silencing of VDAC1 expression induces an inhibition of tumor development. At the same time, along with regulating cellular energy production and metabolism, VDAC1 is involved in the process of mitochondria-mediated apoptosis by mediating the release of apoptotic proteins and interacting with anti-apoptotic proteins. The engagement of VDAC1 in the release of apoptotic proteins located in the inter-membranal space involves VDAC1 oligomerization that mediates the release of cytochrome c and AIF to the cytosol, subsequently leading to apoptotic cell death. Apoptosis can also be regulated by VDAC1, serving as an anchor point for mitochondria-interacting proteins, such as hexokinase (HK), Bcl2 and Bcl-xL, some of which are also highly expressed in many cancers. By binding to VDAC1, HK provides both a metabolic benefit and apoptosis-suppressive capacity that offer the cell a proliferative advantage and increase its resistance to chemotherapy. Thus, these and other functions point to VDAC1 as an excellent target for impairing the re-programed metabolism of cancer cells and their ability to evade apoptosis. Here, we review current evidence pointing to the function of VDAC1 in cell life and death, and highlight these functions in relation to both cancer development and therapy. In addressing the recently solved 3D structures of VDAC1, this review will point to structure-function relationships of VDAC as critical for deciphering how this channel can perform such a variety of roles, all of which are important for cell life and death. Finally, this review will also provide insight into VDAC function in Ca2+ homeostasis, protection against oxidative stress, regulation of apoptosis and involvement in several diseases, as well as its role in the action of different drugs. We will discuss the use of VDAC1-based strategies to attack the altered metabolism and apoptosis of cancer cells. These strategies include specific siRNA able to impair energy and metabolic homeostasis, leading to arrested cancer cell growth and tumor development, as well VDAC1-based peptides that interact with anti-apoptotic proteins to induce apoptosis, thereby overcoming the resistance of cancer cell to chemotherapy. Finally, small molecules targeting VDAC1 can induce apoptosis. VDAC1 can thus be considered as standing at the crossroads between mitochondrial metabolite transport and apoptosis and hence represents an emerging cancer drug target. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

Lentivirus-mediated silencing of SCIN inhibits proliferation of human lung carcinoma cells

SCIN (scinderin) is a calcium-dependent actin severing and capping protein. Homologue in zebrafish has been found to be related with cell death. In the present study, we found that SCIN is highly expressed in human lung cancer specimens. However, the role of SCIN in lung cancer has not yet been determined. To investigate the function of SCIN in lung carcinoma cells, we took advantage of lentivirus-mediated RNA interference (RNAi) to knockdown SCIN expression in two lung carcinoma cell lines A549 and H1299. Silencing of SCIN significantly inhibited the proliferation and colony formation ability of both cell lines in vitro. Moreover, flow cytometry analysis showed that knockdown of SCIN led to G0/G1 phase cell cycle arrest as well as an excess accumulation of cells in the sub-G1 phase. Furthermore, depletion of SCIN resulted in a significant increase in Cyclin B1, p21 and PARP expression, and a little decrease in Cyclin D1 expression. These results suggest that SCIN plays an important role in lung carcinoma cell proliferation, and lentivirus-mediated silencing of SCIN might be a potential therapeutic approach for the treatment of lung cancer.

Cisplatin resistance by induction of aldo-keto reductase family 1 member C2 in human bladder cancer cells

Cisplatin is currently the most effective anti-tumor agent available against bladder cancer. To clarify the mechanism underlying cisplatin resistance in bladder cancer, the present study examined the role of the aldo-keto reductase family 1 member C2 (AKR1C2) protein on chemoresistance using a human bladder cancer cell line. The function of AKR1C2 in chemoresistance was studied using the human HT1376 bladder cancer cell line and the cisplatin-resistant HT1376-CisR subline. AKR1C2 was expressed in HT1376-CisR cells, but not in the parental cells. The effect of small interfering (si) RNAs and an inhibitor targeting AKR1C2 was examined to determine whether cisplatin sensitivity can be rescued by blocking AKR1C2 expression or function. Silencing of AKR1C2 mRNA or inhibition of AKR1C2 by 5β-cholanic acid resulted in a decrease in the survival of cells following cisplatin exposure. Intracellular accumulation of reactive oxygen species (ROS) was determined using a 2,7-dichlorodihydrofluorescein diacetate (H₂DCFDA) fluorescent probe. Cisplatin exposure increased the level of intracellular ROS in HT1376 cells in a dose-dependent manner. The ROS levels in HT1376-CisR cells were significantly lower than those in HT1376 cells and knockdown of AKR1C2 mRNA significantly restored ROS levels. Cisplatin exposure did not increase intracellular ROS in HT1376-CisR cells, although the level of intracellular ROS increased in HT1376 cells following cisplatin exposure. Silencing of AKR1C2 mRNA restored the ROS increase response to cisplatin and menadione as an oxidative stressor in HT1376-CisR cells. Menadione has the function of an oxidative stressor. The silencing of AKR1C2 mRNA restored the increased ROS response to cisplatin and menadione in HT1376-CisR cells. These results indicate that induction of AKR1C2 in human bladder cancer cells aids in the development of cisplatin resistance through antioxidative effects. The results of this study indicate that AKR1C2 may be an effective molecular target for restoring cisplatin resistance.

Expression of EPHRIN-A1, SCINDERIN and MHC class I molecules in head and neck cancers and relationship with the prognostic value of intratumoral CD8+ T cells

Background

Our group has previously shown that EPHRIN-A1 and SCINDERIN expression by tumor cells rendered them resistant to cytotoxic T lymphocyte-mediated lysis. Whereas the prognostic value of EPHRIN-A1 expression in cancer has already been studied, the role of SCINDERIN presence remains to be established. In the present work, we investigated the prognosis value of EPHRIN-A1 and SCINDERIN expression in head and neck carcinomas. In addition, we monitored the HLA-class I expression by tumor cells and the presence of tumor-infiltrating CD8⁺ T cells to evaluate a putative correlation between these factors and the survival prognosis by themselves or related to EPHRIN-A1 and SCINDERIN expression.

Methods

Tumor tissue sections of 83 patients with head and neck cancer were assessed by immunohistochemistry for the expression of EPHRIN-A1, SCINDERIN, HLA class I molecules and the presence of CD8⁺ T cells.

Results

No significant prognosis value could be attributed to these factors independently, despite a tendency of association between EPHRIN-A1 and a worse clinical outcome. No prognostic value could be observed when CD8⁺ T cell tumor infiltration was analyzed combined with EPHRIN-A1, SCINDERIN or HLA class I expression.

Conclusion

These results highlight that molecules involved in cancer cell resistance to cytotoxic T lymphocytes by themselves are not a sufficient criteria for prognosis determination in cancer patients. Other intrinsic or tumor microenvironmental features should be considered in prognostic evaluation.

Suppression of SCIN inhibits human prostate cancer cell proliferation and induces G0/G1 phase arrest

SCIN is a calcium regulated actin severing and capping protein. Its homologue in zebrafish is found to be related with cell death. In the present study, we found that SCIN is highly expressed in human prostate cancer specimens. However, the functions of SCIN in human prostate carcinoma cells are largely unknown. To address the function of SCIN in prostate carcinoma cells, we used lentivirus-mediated RNAi to knock down SCIN expression in PC3 cells, a prostate carcinoma cell line. We found that in vitro silencing of SCIN could inhibit the proliferation and colony formation ability of PC3 cells. Furthermore, cell cycle analysis showed that reduced SCIN expression lead to G0/G1 cell cycle arrest through the regulation of cell cycle-related genes, such as p21Waf1/Cip1, cyclin-dependent kinase inhibitor 2A (CDKN2A, p16Ink4A) and cyclin A2. These results suggest that SCIN plays an important role in the proliferation of prostate cancer cells and lentivirus-mediated inhibition of SCIN expression may be a potential therapeutic method for the treatment of prostate cancer.

Lin28a is a putative factor in regulating cancer stem cell-like properties in side population cells of oral squamous cell carcinoma

Cancer stem cells (CSCs) are among the target cells of cancer therapy because they are uniquely involved in both cancer progression and sensitivity to chemotherapeutic agents. We identified side population (SP) cells, which are known to be an enriched population of CSC, in five oral squamous cell carcinoma (OSCC) cells (SCC9, SCC25, TOSCC7, TOSCC17, and TOSCC23). The percentages of SP cells ranged from 0% to 3.3%, with TOSCC23 cells showing the highest percentages of SP cells (3.3% of the total cell population). The SP cells isolated from TOSCC23 cells also showed greater cell proliferation and invasion compared to non-SP (MP) cells. Therefore, our initial findings suggested that SP cells were enriched for CSC-like cells. Furthermore, DNA microarray analysis revealed that the expression of cell proliferation-related and anti-apoptotic genes was greater in SP cells compared to MP cells. We focused on Lin28a, which showed the highest expression (approximately 22-fold) among the upregulated genes. The overexpression of Lin28a in TOSCC23 cells increased their proliferation, colony formation, and invasion. These findings suggest that Lin28a is an appropriate CSC target molecule for OSCC treatment.

Does phosphorylation of cofilin affect the progression of human bladder cancer?

Background

We determined the differently expressed protein profiles and their functions in bladder cancer tissues with the aim of identifying possible target proteins and underlying molecular mechanisms for taking part in their progression.

Methods

We examined the expression of proteins by proteomic analysis and western blot in normal urothelium, non-muscle-invasive bladder cancers (NMIBCs), and muscle-invasive bladder cancers (MIBCs). The function of cofilin was analyzed using T24 human bladder cancer cells.

Results

The expression levels of 12 proteins were altered between bladder cancers and normal bladder tissues. Of these proteins, 14-3-3σ was upregulated in both NMIBCs and MIBCs compared with controls. On the other hand, myosin regulatory light chain 2, galectin-1, lipid-binding AI, annexin V, transthyretin, CARD-inhibitor of NF-κB-activating ligand, and actin prepeptide were downregulated in cancer samples. Cofilin, an actin-depolymerizing factor, was prominent in both NMIBCs and MIBCs compared with normal bladder tissues. Furthermore, we confirmed that cofilin phosphorylation was more prominent in MIBCs than in NMIBCs using immunoblotting and immunohistochemcal analyses. Epidermal growth factor (EGF) increased the phosphorylation of cofilin and elevated the migration in T24 cells. Knockdown of cofilin expression with small interfering RNA attenuated the T24 cell migration in response to EGF.

Conclusions

These results demonstrate that the increased expression and phosphorylation of cofilin might play a role in the occurrence and invasiveness of bladder cancer. We suspected that changes in cofilin expression may participate in the progression of the bladder cancer.

VDAC1: from structure to cancer therapy

Here, we review current evidence pointing to the function of VDAC1 in cell life and death, and highlight these functions in relation to cancer. Found at the outer mitochondrial membrane, VDAC1 assumes a crucial position in the cell, controlling the metabolic cross-talk between mitochondria and the rest of the cell. Moreover, its location at the boundary between the mitochondria and the cytosol enables VDAC1 to interact with proteins that mediate and regulate the integration of mitochondrial functions with other cellular activities. As a metabolite transporter, VDAC1 contributes to the metabolic phenotype of cancer cells. This is reflected by VDAC1 over-expression in many cancer types, and by inhibition of tumor development upon silencing VDAC1 expression. Along with regulating cellular energy production and metabolism, VDAC1 is also a key protein in mitochondria-mediated apoptosis, participating in the release of apoptotic proteins and interacting with anti-apoptotic proteins. The involvement of VDAC1 in the release of apoptotic proteins located in the inter-membranal space is discussed, as is VDAC1 oligomerization as an important step in apoptosis induction. VDAC also serves as an anchor point for mitochondria-interacting proteins, some of which are also highly expressed in many cancers, such as hexokinase (HK), Bcl2, and Bcl-xL. By binding to VDAC, HK provides both metabolic benefit and apoptosis-suppressive capacity that offers the cell a proliferative advantage and increases its resistance to chemotherapy. VDAC1-based peptides that bind specifically to HK, Bcl2, or Bcl-xL abolished the cell’s abilities to bypass the apoptotic pathway. Moreover, these peptides promote cell death in a panel of genetically characterized cell lines derived from different human cancers. These and other functions point to VDAC1 as a rational target for the development of a new generation of therapeutics.

Adseverin: a novel cisplatin-resistant marker in the human bladder cancer cell line HT1376 identified by quantitative proteomic analysis

Cisplatin is currently the most effective antitumor agent available against bladder cancer. However, a majority of patients eventually relapse with cisplatin-resistant disease. Chemoresistance thus remains a major obstacle in bladder cancer therapy. To clarify the molecular mechanisms underlying cisplatin resistance in bladder cancer, we established a cisplatin-resistant subline from the human bladder cancer cell line HT1376 (HT1376-CisR), and conducted large-scale analyses of the expressed proteins using two-dimensional (2D) gel electrophoresis coupled with mass spectrometry (MS). Comparative proteomic analysis of HT1376 and HT1376-CisR cells revealed 36 differentially expressed proteins, wherein 21 proteins were upregulated and 15 were downregulated in HT1376-CisR cells. Among the differentially regulated proteins, adseverin (SCIN), a calcium-dependent actin-binding protein, was overexpressed (4-fold upregulation) in HT1376-CisR, with the increase being more prominent in the mitochondrial fraction than in the cytosol fraction. SCIN mRNA knockdown significantly reduced cell proliferation with mitochondria-mediated apoptosis in HT1376-CisR cells. Immunoprecipitation analysis revealed voltage-dependent anion channels (VDACs) to be bound to SCIN in the mitochondrial fraction. Our results suggest that the VDAC-SCIN interaction may inhibit mitochondria-mediated apoptosis in cisplatin-resistant cells. Targeting the VDAC-SCIN interaction may offer a new therapeutic strategy for cisplatin-resistant bladder cancer.