Assessment of gene expression of intracellular calcium channels, pumps and exchangers with epidermal growth factor-induced epithelial-mesenchymal transition in a breast cancer cell line

TMBIM6/BI-1 is an intracellular environmental regulator that induces paraptosis in cancer via ROS and Calcium-activated ERAD II pathways

Transmembrane B cell lymphoma 2-associated X protein inhibitor motif-containing (TMBIM) 6, also known as Bax Inhibitor-1 (BI-1), has been heavily researched for its cytoprotective functions. TMBIM6 functional diversity includes modulating cell survival, stress, metabolism, cytoskeletal dynamics, organelle function, regulating cytosolic acidification, calcium, and reactive oxygen species (ROS). Clinical research shows TMBIM6 plays a key role in many of the world's top diseases/injuries (i.e., Alzheimer's, Parkinson's, diabetes, obesity, brain injury, liver disease, heart disease, aging, etc.), including cancer, where TMBIM6 expression impacts patient survival, chemoresistance, cancer progression, and metastasis. We show TMBIM6 is activated by, and undergoes, different conformational changes that dictate its function following a significant change in the cell's IntraCellular Environment (ICE). TMBIM6 agonism, following ICE change, can help the cell overcome multiple stresses including toxin exposure, viral infection, wound healing, and excitotoxicity. However, in cancer cells TMBIM6 agonism results in rapid paraptotic induction irrespective of the cancer type, sub-type, genotype or phenotype. Furthermore, the level of TMBIM6 expression in cancer did not dictate the level of paraptotic induction; however, it did dictate the rate at which paraptosis occurred. TMBIM6 agonism did not induce paraptosis in cancer via canonical routes involving p38 MAPK, JNK, ERK, UPR, autophagy, proteasomes, or Caspase-9. Instead, TMBIM6 agonism in cancer upregulates cytosolic Ca2+ and ROS, activates lysosome biogenesis, and induces paraptosis via ERAD II mechanisms. In xenograft models, we show TMBIM6 agonism induces rapid cancer cell death with no toxicity, even at high doses of TMBIM6 agonist (>450 mg/kg). In summary, this study shows TMBIM6's functional diversity is only activated by severe ICE change in diseased/injured cells, highlighting its transformative potential as a therapeutic target across various diseases and injuries, including cancer.

Single-cell tracking as a tool for studying EMT-phenotypes

This article demonstrates that label-free single-cell video tracking is a useful approach for in vitro studies of Epithelial-Mesenchymal Transition (EMT). EMT is a highly heterogeneous process, involved in wound healing, embryogenesis and cancer. The process promotes metastasis, and increased understanding can aid development of novel therapeutic strategies. The role of EMT-associated biomarkers depends on biological context, making it challenging to compare and interpret data from different studies. We demonstrate single-cell video tracking for comprehensive phenotype analysis. In this study we performed single-cell video tracking on 72-h long recordings. We quantified several behaviours at a single-cell level during induced EMT in MDA-MB-468 cells. This revealed notable variations in migration speed, with different dose-response patterns and varying distributions of speed. By registering cell morphologies during the recording, we determined preferred paths of morphological transitions. We also found a clear association between migration speed and cell morphology. We found elevated rates of cell death, diminished proliferation, and an increase in mitotic failures followed by re-fusion of sister-cells. The method allows tracking of phenotypes in cell lineages, which can be particularly useful in epigenetic studies. Sister-cells were found to have significant similarities in their speeds and morphologies, illustrating the heritability of these traits.

Inositol (1,4,5)-Trisphosphate Receptors in Invasive Breast Cancer: A New Prognostic Tool?

Simple Summary

The inositol-trisphosphate receptor (IP₃R) is a key player in physiological and pathological intracellular calcium signaling. The objective of the present study was to assess the putative value of the three IP₃R subtypes as prognostic biomarkers in breast cancer. We found that IP₃R3 is the most strongly expressed subtype in breast cancer tissue. Furthermore, IP₃R3 and IP₃R1 are significantly more expressed in invasive breast cancer tissue than in non-tumor tissue. In contrast to IP₃R1 and IP₃R2, the expression of IP₃R3 was positively correlated with prognostic factors including tumor size, regional node invasion, histologic grade, proliferation index, and hormonal status. By analyzing public databases, we found that the expression of all IP₃R subtypes is significantly correlated with the overall survival and disease-free survival of patients with breast cancer. We conclude that relative to the other two IP₃R subtypes, IP₃R3 expression is upregulated in breast cancer and is correlated with prognostic factors. We strongly believe that our results will open up new perspectives with regard to the link between IP₃Rs and breast cancer aggressiveness.

Abstract

Breast cancer is the leading cause of cancer death among women in worldwide and France. The disease prognosis and treatment differ from one breast cancer subtype to another, and the disease outcome depends on many prognostic factors. Deregulation of ion flux (especially Ca²⁺ flux) is involved in many pathophysiology processes, including carcinogenesis. Inside the cell, the inositol-trisphosphate receptor (IP₃R) is a major player in the regulation of the Ca²⁺ flux from the endoplasmic reticulum to the cytoplasm. The IP₃Rs (and particularly the IP₃R3 subtype) are known to be involved in proliferation, migration, and invasion processes in breast cancer cell lines. The objective of the present study was to evaluate the potential value of IP₃Rs as prognostic biomarkers in breast cancer. We found that expression levels of IP₃R3 and IP₃R1 (but not IP₃R2) were significantly higher in invasive breast cancer of no special type than in non-tumor tissue from the same patient. However, the IP₃R3 subtype was expressed more strongly than the IP₃R1 and IP₃R2 subtypes. Furthermore, the expression of IP₃R3 (but not of IP₃R1 or IP₃R2) was positively correlated with prognostic factors such as tumor size, regional node invasion, histologic grade, proliferation index, and hormone receptor status. In an analysis of public databases, we found that all IP₃Rs types are significantly associated with overall survival and progression-free survival in patients with breast cancer. We conclude that relative to the other two IP₃R subtypes, IP₃R3 expression is upregulated in breast cancer and is correlated with prognostic factors.

Epithelial-mesenchymal transition process during embryo implantation

The epithelial to mesenchymal transition (EMT) in endometrial epithelial and trophectoderm cells is essential for the progression of embryo implantation and its impairment could cause implantation failure. Therefore, EMT should be tightly regulated in both embryonic and endometrial cells during implantation. Studies reported the involvement of numerous factors in EMT regulation, including hormones, growth factors, transcription factors, microRNAs, aquaporins (AQPs), and ion channels. These factors act through different signaling pathways to affect the expression of epithelial and mesenchymal markers as well as the cellular cytoskeleton. Although the mechanisms involved in cancer cell EMT have been well studied, little is known about EMT during embryo implantation. Therefore, we comprehensively reviewed different factors that regulate the EMT, a key event required for the conceptus implantation to the endometrium.Summary sentence: Abnormal epithelial-mesenchymal transition (EMT) process within endometrial epithelial cells (EECs) or trophoblast cells can cause implantation failure. This process is regulated by various factors. Thus, the objective of this review was to summarize the effective factors on the EMT process during implantation.

UDP-glucose dehydrogenase expression is upregulated following EMT and differentially affects intracellular glycerophosphocholine and acetylaspartate levels in breast mesenchymal cell lines

Metabolic rewiring is one of the indispensable drivers of epithelial-mesenchymal transition (EMT) involved in breast cancer metastasis. In this study, we explored the metabolic changes during spontaneous EMT in three separately established breast EMT cell models using a proteomics approach supported by metabolomic analysis. We identified common proteomic changes, including in the expression of CDH1, CDH2, VIM, LGALS1, SERPINE1, PKP3, ATP2A2, JUP, MTCH2, RPL26L1 and PLOD2. Consistently altered metabolic enzymes included: FDFT1, SORD, TSTA3 and UDP-glucose dehydrogenase (UGDH). Of these, UGDH was most prominently altered and has previously been associated with breast cancer patient survival. siRNA-mediated knockdown of UGDH resulted in delayed cell proliferation and dampened invasive potential of mesenchymal cells, and downregulated expression of the EMT transcription factor SNAI1. Metabolomic analysis revealed that siRNA-mediated knockdown of UGDH decreased intracellular glycerophosphocholine (GPC), whereas levels of acetylaspartate (NAA) increased. Finally, our data suggested that platelet-derived growth factor receptor beta (PDGFRB) signaling was activated in mesenchymal cells. siRNA-mediated knockdown of PDGFRB downregulated UGDH expression, potentially via NFkB-p65. Our results support an unexplored relationship between UGDH and GPC, both of which have previously been independently associated with breast cancer progression.

Identification of Three Potential Prognostic Genes in Platinum-Resistant Ovarian Cancer via Integrated Bioinformatics Analysis

Purpose

Ovarian cancer is the most lethal gynecologic malignancy. Resistance to platinum-based chemotherapy affects the overall survival of patients. This study used an integrated bioinformatics to find the poorly understood molecular mechanisms underlying platinum resistance in ovarian cancer.

Methods

Based on the RNA-seq data of tissues in The Cancer Genome Atlas (TCGA) and RNA-seq data of cells from the Cancer Cell Encyclopedia (CCLE), we integrated differentially expressed genes (DEGs) in ovarian cancer tissue and cells. After screening for DEGs related to platinum resistance, we conducted survival analysis and built protein interaction networks to identify genes that may affect prognosis and interact with each other. Least absolute shrinkage and selection operator (Lasso) regression analysis was used to construct a predictive model. Immunohistochemistry and Western blot were used to validate the results. Finally, gene set enrichment analysis (GSEA) was performed on the expression of genes individually.

Results

We found that ATPase Na⁺/K⁺ transporting subunit alpha 2 (ATP1A2), calsequestrin 2 (CASQ2) and ryanodine receptor 2 (RYR2) interacted with each other and could predict resistance to platinum-based therapy, correlating negatively with prognosis. Moreover, we constructed a predictive model based on nine genes, including ATP1A2 and CASQ2. Immunohistochemistry and Western blot validated the upregulation of these genes in ovarian cancer tissue samples and cell lines. The immunohistochemistry results also confirmed the prognostic value of ATP1A2, CASQ2 and RYR2. GSEA predicted that ATP1A2, CASQ2 and RYR2 may act on the KRAS and mTORC1 pathways and participate in metabolic reprogramming and regulation of calcium homeostasis in platinum-resistant cells.

Conclusion

ATP1A2, CASQ2 and RYR2 were highly expressed in platinum-resistant ovarian cancer. ATP1A2 and CASQ2 were related to the prognosis of platinum-resistant ovarian cancer patients. These genes might act on KARS and mTORC1 pathways and participate in metabolic reprogramming and regulation of calcium homeostasis in platinum-resistant cells.

Bioinformatic Analysis of Immune Significance of RYR2 Mutation in Breast Cancer

BACKGROUND

Currently, immunotherapy is widely used for breast cancer (BC) patients, and tumor mutation burden (TMB) is regarded as a valuable independent predictor of response to immunotherapy. However, specific gene mutations and their relationship with TMB and tumor-infiltrating immune cells in BC are not fully understood.

METHODS

Comprehensive bioinformatic analyses were performed using data from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) datasets. Survival curves were analyzed via Kaplan-Meier analysis. Univariate and multivariate Cox regression analyses were used for prognosis analysis. Gene set enrichment analysis (GSEA) was performed to explore regulatory mechanisms and functions. The CIBERSORT algorithm was used to calculate the tumor-infiltrating immune cell fractions.

RESULTS

We analyzed somatic mutation data of BC from TCGA and ICGC datasets and found that 19 frequently mutated genes were reported in both cohorts, namely, SPTA1, TTN, MUC17, MAP3K1, CDH1, FAT3, SYNE1, FLG, HMCN1, RYR2 (ryanodine receptor 2), GATA3, MUC4, PIK3CA, KMT2C, TP53, PTEN, ZFHX4, MUC16, and USH2A. Among them, we observed that RYR2 mutation was significantly associated with higher TMB and better clinical prognosis. Moreover, GSEA revealed that RYR2 mutation-enriched signaling pathways were related to immune-associated pathways. Furthermore, based on the CIBERSORT algorithm, we found that RYR2 mutation enhanced the antitumor immune response by enriching CD8+ T cells, activated memory CD4+ T cells, and M1 macrophages.

CONCLUSION

RYR2 is frequently mutated in BC, and its mutation is related to increased TMB and promotes antitumor immunity; thus, RYR2 may serve as a valuable biomarker to predict the immune response.

Oxygen sensing, mitochondrial biology and experimental therapeutics for pulmonary hypertension and cancer

The homeostatic oxygen sensing system (HOSS) optimizes systemic oxygen delivery. Specialized tissues utilize a conserved mitochondrial sensor, often involving NDUFS2 in complex I of the mitochondrial electron transport chain, as a site of pO₂-responsive production of reactive oxygen species (ROS). These ROS are converted to a diffusible signaling molecule, hydrogen peroxide (H₂O₂), by superoxide dismutase (SOD2). H₂O₂ exits the mitochondria and regulates ion channels and enzymes, altering plasma membrane potential, intracellular Ca²⁺ and Ca²⁺-sensitization and controlling acute, adaptive, responses to hypoxia that involve changes in ventilation, vascular tone and neurotransmitter release. Subversion of this O₂-sensing pathway creates a pseudohypoxic state that promotes disease progression in pulmonary arterial hypertension (PAH) and cancer. Pseudohypoxia is a state in which biochemical changes, normally associated with hypoxia, occur despite normal pO₂. Epigenetic silencing of SOD2 by DNA methylation alters H₂O₂ production, activating hypoxia-inducible factor 1α, thereby disrupting mitochondrial metabolism and dynamics, accelerating cell proliferation and inhibiting apoptosis. Other epigenetic mechanisms, including dysregulation of microRNAs (miR), increase pyruvate dehydrogenase kinase and pyruvate kinase muscle isoform 2 expression in both diseases, favoring uncoupled aerobic glycolysis. This Warburg metabolic shift also accelerates cell proliferation and impairs apoptosis. Disordered mitochondrial dynamics, usually increased mitotic fission and impaired fusion, promotes disease progression in PAH and cancer. Epigenetic upregulation of dynamin-related protein 1 (Drp1) and its binding partners, MiD49 and MiD51, contributes to the pathogenesis of PAH and cancer. Finally, dysregulation of intramitochondrial Ca²⁺, resulting from impaired mitochondrial calcium uniporter complex (MCUC) function, links abnormal mitochondrial metabolism and dynamics. MiR-mediated decreases in MCUC function reduce intramitochondrial Ca²⁺, promoting Warburg metabolism, whilst increasing cytosolic Ca²⁺, promoting fission. Epigenetically disordered mitochondrial O₂-sensing, metabolism, dynamics, and Ca²⁺ homeostasis offer new therapeutic targets for PAH and cancer. Promoting glucose oxidation, restoring the fission/fusion balance, and restoring mitochondrial calcium regulation are promising experimental therapeutic strategies.

Advances in the study of cancer metastasis and calcium signaling as potential therapeutic targets

Metastasis is still the primary cause of cancer-related mortality. However, the underlying mechanisms of cancer metastasis are not yet fully understood. Currently, the epithelial-mesenchymal transition, metabolic remodeling, cancer cell intercommunication and the tumor microenvironment including diverse stromal cells, are reported to affect the metastatic process of cancer cells. Calcium ions (Ca²⁺) are ubiquitous second messengers that manipulate cancer metastasis by affecting signaling pathways. Diverse transporter/pump/channel-mediated Ca²⁺ currents form Ca²⁺ oscillations that can be decoded by Ca²⁺-binding proteins, which are promising prognostic biomarkers and therapeutic targets of cancer metastasis. This paper presents a review of the advances in research on the mechanisms underlying cancer metastasis and the roles of Ca²⁺-related signals in these events.

Radiomics and gene expression profile to characterise the disease and predict outcome in patients with lung cancer

Objective

The objectives of our study were to assess the association of radiomic and genomic data with histology and patient outcome in non-small cell lung cancer (NSCLC).

Methods

In this retrospective single-centre observational study, we selected 151 surgically treated patients with adenocarcinoma or squamous cell carcinoma who performed baseline [18F] FDG PET/CT. A subgroup of patients with cancer tissue samples at the Institutional Biobank (n = 74/151) was included in the genomic analysis. Features were extracted from both PET and CT images using an in-house tool. The genomic analysis included detection of genetic variants, fusion transcripts, and gene expression. Generalised linear model (GLM) and machine learning (ML) algorithms were used to predict histology and tumour recurrence.

Results

Standardised uptake value (SUV) and kurtosis (among the PET and CT radiomic features, respectively), and the expression of TP63, EPHA10, FBN2, and IL1RAP were associated with the histotype. No correlation was found between radiomic features/genomic data and relapse using GLM. The ML approach identified several radiomic/genomic rules to predict the histotype successfully. The ML approach showed a modest ability of PET radiomic features to predict relapse, while it identified a robust gene expression signature able to predict patient relapse correctly. The best-performing ML radiogenomic rule predicting the outcome resulted in an area under the curve (AUC) of 0.87.

Conclusions

Radiogenomic data may provide clinically relevant information in NSCLC patients regarding the histotype, aggressiveness, and progression. Gene expression analysis showed potential new biomarkers and targets valuable for patient management and treatment. The application of ML allows to increase the efficacy of radiogenomic analysis and provides novel insights into cancer biology.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05371-7.

The ER-mitochondria Ca2+ signaling in cancer progression: Fueling the monster

Cancer is a leading cause of death worldwide. All major tumor suppressors and oncogenes are now recognized to have fundamental connections with metabolic pathways. A hallmark feature of cancer cells is a reprogramming of their metabolism even when nutrients are available. Increasing evidence indicates that most cancer cells rely on mitochondrial metabolism to sustain their energetic and biosynthetic demands. Mitochondria are functionally and physically coupled to the endoplasmic reticulum (ER), the major calcium (Ca²⁺) storage organelle in mammalian cells, through special domains known as mitochondria-ER contact sites (MERCS). In this domain, the release of Ca²⁺ from the ER is mainly regulated by inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs), a family of Ca²⁺ release channels activated by the ligand IP3. IP3R mediated Ca²⁺ release is transferred to mitochondria through the mitochondrial Ca²⁺ uniporter (MCU). Once in the mitochondrial matrix, Ca²⁺ activates several proteins that stimulate mitochondrial performance. The role of IP3R and MCU in cancer, as well as the other proteins that enable the Ca²⁺ communication between these two organelles is just beginning to be understood. Here, we describe the function of the main players of the ER mitochondrial Ca²⁺ communication and discuss how this particular signal may contribute to the rise and development of cancer traits.

Ca2+ Signaling as the Untact Mode during Signaling in Metastatic Breast Cancer

Metastatic features of breast cancer in the brain are considered a common pathology in female patients with late-stage breast cancer. Ca2+ signaling and the overexpression pattern of Ca2+ channels have been regarded as oncogenic markers of breast cancer. In other words, breast tumor development can be mediated by inhibiting Ca2+ channels. Although the therapeutic potential of inhibiting Ca2+ channels against breast cancer has been demonstrated, the relationship between breast cancer metastasis and Ca2+ channels is not yet understood. Thus, we focused on the metastatic features of breast cancer and summarized the basic mechanisms of Ca2+-related proteins and channels during the stages of metastatic breast cancer by evaluating Ca2+ signaling. In particular, we highlighted the metastasis of breast tumors to the brain. Thus, modulating Ca2+ channels with Ca2+ channel inhibitors and combined applications will advance treatment strategies for breast cancer metastasis to the brain.

Deciphering the Role of Ca2+ Signalling in Cancer Metastasis: From the Bench to the Bedside

Metastatic cancer is one of the major causes of cancer-related mortalities. Metastasis is a complex, multi-process phenomenon, and a hallmark of cancer. Calcium (Ca2+) is a ubiquitous secondary messenger, and it has become evident that Ca2+ signalling plays a vital role in cancer. Ca2+ homeostasis is dysregulated in physiological processes related to tumour metastasis and progression-including cellular adhesion, epithelial-mesenchymal transition, cell migration, motility, and invasion. In this review, we looked at the role of intracellular and extracellular Ca2+ signalling pathways in processes that contribute to metastasis at the local level and also their effects on cancer metastasis globally, as well as at underlying molecular mechanisms and clinical applications. Spatiotemporal Ca2+ homeostasis, in terms of oscillations or waves, is crucial for hindering tumour progression and metastasis. They are a limited number of clinical trials investigating treating patients with advanced stages of various cancer types. Ca2+ signalling may serve as a novel hallmark of cancer due to the versatility of Ca2+ signals in cells, which suggests that the modulation of specific upstream/downstream targets may be a therapeutic approach to treat cancer, particularly in patients with metastatic cancers.

Biological Regulatory Network (BRN) Analysis and Molecular Docking Simulations to Probe the Modulation of IP3R Mediated Ca2+ Signaling in Cancer

Inositol trisphosphate receptor (IP3R) mediated Ca+2 signaling is essential in determining the cell fate by regulating numerous cellular processes, including cell division and cell death. Despite extensive studies about the characterization of IP3R in cancer, the underlying molecular mechanism initiating the cell proliferation and apoptosis remained enigmatic. Moreover, in cancer, the modulation of IP3R in downstream signaling pathways, which control oncogenesis and cancer progression, is not well characterized. Here, we constructed a biological regulatory network (BRN), and describe the remodeling of IP3R mediated Ca2+ signaling as a central key that controls the cellular processes in cancer. Moreover, we summarize how the inhibition of IP3R affects the deregulated cell proliferation and cell death in cancer cells and results in the initiation of pro-survival responses in resistance of cell death in normal cells. Further, we also investigated the role of stereo-specificity of IP3 molecule and its analogs in binding with the IP3 receptor. Molecular docking simulations showed that the hydroxyl group at R6 position along with the phosphate group at R5 position in 'R' conformation is more favorable for IP3 interactions. Additionally, Arg-266 and Arg-510 showed π-π and hydrogen bond interactions and Ser-278 forms hydrogen bond interactions with the IP3 binding site. Thus, they are identified as crucial for the binding of antagonists.

Inhibition to Epithelial-Mesenchymal Transition and Metastatic Potential In Colorectal Cancer Cell By Combination of Traditional Chinese Medicine Formulation Jiedu Sangen Decoction and PD-L1 Inhibitor

BACKGROUND

Jiedu Sangen Decoction (JSD), a traditional Chinese medicine formula, has been widely applied in the treatment of gastrointestinal cancer, especially in colorectal cancer. Our study mainly aimed to assess the combined efficacy of Jiedu Sangen aqueous extract (JSAE) and a PD-L1 inhibitor (PI) in colon cancer cells migration and invasion, along with epithelial-mesenchymal transition, and then provide deep insights into the potential mechanism.

METHODS

We explored the inhibitory effects on invasion and metastasis and the reverse effect on EMT process in CT-26 colon cancer cell via Transwell migration assay, Matrigel invasion assay and confocal laser scanning microscopy. Furthermore, regulation in expression of EMT-related proteins and molecular biomarkers and underlying signal pathway proteins were detected through Western blotting and IHC.

RESULTS

The combination of JSD and PD-L1 inhibitor could inhibit migration, invasive ability and EMT of CT-26 cells in a concentration-dependent manner. Meanwhile, JSD combined with PD-L1 inhibitor could also remarkably reverse EMT and metastasis in vivo. In addition, the protein expression of N-cadherin, Slug, Snail, Vimentin was down-regulated along with E-cadherin s up-regulation with the combination of JSD and PD-L1 inhibitor, while that of PI3K/AKT was notably down-regulated.

CONCLUSIONS

These findings indicated that JSAE and a PD-L1 inhibitor could drastically inhibit the migration and invasion of colorectal cancer by reversing EMT through the PI3K/AKT signaling pathway.

Lessons from the Endoplasmic Reticulum Ca2+ Transporters-A Cancer Connection

Ca2+ is an integral mediator of intracellular signaling, impacting almost every aspect of cellular life. The Ca2+-conducting transporters located on the endoplasmic reticulum (ER) membrane shoulder the responsibility of constructing the global Ca2+ signaling landscape. These transporters gate the ER Ca2+ release and uptake, sculpt signaling duration and intensity, and compose the Ca2+ signaling rhythm to accommodate a plethora of biological activities. In this review, we explore the mechanisms of activation and functional regulation of ER Ca2+ transporters in the establishment of Ca2+ homeostasis. We also contextualize the aberrant alterations of these transporters in carcinogenesis, presenting Ca2+-based therapeutic interventions as a means to tackle malignancies.

Impact of NR5A2 and RYR2 3'UTR polymorphisms on the risk of breast cancer in a Chinese Han population

OBJECTIVES

The NR5A2 and RYR2 genes are important players in steroid metabolism and play an important role in cancer research. In this research, we want to evaluate the effect of NR5A2 and RYR2 polymorphisms on breast cancer (BC).

METHODS

Four single nucleotide polymorphisms on NR5A2 and RYR2 were selected to genotype by Agena MassARRAY in 379 BC patients and 407 healthy controls. Using the PLINK software to calculate the Odds ratio (OR) and 95% confidence intervals (CIs) via the logistic regression analysis to evaluate the risk for BC.

RESULTS

We found that NR5A2 rs2246209 significantly decreased the risk of BC with the AA genotype (OR 0.58, 95%CI 0.34-0.99, p = 0.049), and recessive model (OR 0.59, 95%CI 0.35-0.99, p = 0.046); rs12594 in the RYR2 gene significantly decreased the risk of BC in the GG genotype (OR 0.44, 95%CI 0.22-0.88, p = 0.020), and recessive model (OR 0.43, 95%CI 0.21-0.85, p = 0.016). Further stratification analysis showed that NR5A2 rs2246209 was related to a lower incidence of BC affected by age, lymph nodes metastasis, and tumor stage; RYR2 rs12594 was related to a decreased BC risk restricted by age, estrogen receptor (ER), progesterone receptor (PR), menopausal status, tumor size, and tumor stage. Rs12594 in the RyR2 gene remained significant on the genetic susceptibility of PR-positive BC after Bonferroni correction (p < 0.0125).

CONCLUSIONS

This study provides an evidence that NR5A2 rs2246209 and RYR2 rs12594 decreased the risk of breast cancer.

From Orai to E-Cadherin: Subversion of Calcium Trafficking in Cancer to Drive Proliferation, Anoikis-Resistance, and Metastasis

The common currency of epithelial differentiation and homeostasis is calcium, stored primarily in the endoplasmic reticulum, rationed according to need, and replenished from the extracellular milieu via store-operated calcium entry (SOCE). This currency is disbursed by the IP3 receptor in response to diverse extracellular signals. The rate of release is governed by regulators of proliferation, autophagy, survival, and programmed cell death, the strength of the signal leading to different outcomes. Intracellular calcium acts chiefly through intermediates such as calmodulin that regulates growth factor receptors such as epidermal growth factor receptor (EGFR), actin polymerization, and adherens junction assembly and maintenance. Here we review this machinery and its role in differentiation, then consider how cancer cells subvert it to license proliferation, resist anoikis, and enable metastasis, either by modulating the level of intracellular calcium or its downstream targets or effectors such as EGFR, E-cadherin, IQGAP1, TMEM16A, CLCA2, and TRPA1. Implications are considered for the roles of E-cadherin and growth factor receptors in circulating tumor cells and metastasis. The discovery of novel, cell type-specific modulators and effectors of calcium signaling offers new possibilities for cancer chemotherapy.

Perioperative COX2 and β-adrenergic blockade improves biomarkers of tumor metastasis, immunity, and inflammation in colorectal cancer: A randomized controlled trial

BACKGROUND

Preclinical studies have implicated excess release of catecholamines and prostaglandins in the mediation of prometastatic processes during surgical treatment of cancer. In this study, we tested the combined perioperative blockade of these pathways in patients with colorectal cancer (CRC).

METHODS

In a randomized, double-blind, placebo-controlled biomarker trial involving 34 patients, the β-blocker propranolol and the COX2-inhibitor etodolac were administered for 20 perioperative days, starting 5 days before surgery. Excised tumors were subjected to whole genome messenger RNA profiling and transcriptional control pathway analyses.

RESULTS

Drugs were well-tolerated, with minor complications in both the treatment group and the placebo group. Treatment resulted in a significant improvement (P < .05) of tumor molecular markers of malignant and metastatic potential, including 1) reduced epithelial-to-mesenchymal transition, 2) reduced tumor infiltrating CD14⁺ monocytes and CD19⁺ B cells, and 3) increased tumor infiltrating CD56⁺ natural killer cells. Transcriptional activity analyses indicated a favorable drug impact on 12 of 19 a priori hypothesized CRC-related transcription factors, including the GATA, STAT, and EGR families as well as the CREB family that mediates the gene regulatory impact of β-adrenergic- and prostaglandin-signaling. Alterations observed in these transcriptional activities were previously associated with improved long-term clinical outcomes. Three-year recurrence rates were assessed for long-term safety analyses. An intent-to-treat analysis revealed that recurrence rates were 12.5% (2/16) in the treatment group and 33.3% (6/18) in the placebo group (P = .239), and in protocol-compliant patients, recurrence rates were 0% (0/11) in the treatment group and 29.4% (5/17) in the placebo group (P = .054).

CONCLUSIONS

The favorable biomarker impacts and clinical outcomes provide a rationale for future randomized placebo-controlled trials in larger samples to assess the effects of perioperative propranolol/etodolac treatment on oncological clinical outcomes.

Rapid and Targeted Photoactivation of Ca2+ Channels Mediated by Squaraine To Regulate Intracellular and Intercellular Signaling Processes

As an important cellular signal transduction messenger, Ca²⁺ has the capability to regulate cell function and control many biochemical processes, including metabolism, gene expression, and cell survival and death. Here, we introduce an accessible method for the photoactivation of Ca²⁺ channels mediated by squaraine (SQ) to rapidly induce cellular Ca²⁺ release and activate signal transduction. With a short preparation time, the maximum Ca²⁺ concentration increase could reach approximately 450% in 30 s, resulting from marked Ca²⁺ release channel opening in the endoplasmic reticulum (ER). This release was enhanced by another target location of SQ, that is, the outer mitochondrial-associated membrane where Ca²⁺ channels accumulate, and by the consequent large amounts of reactive oxygen species resulting from the respiratory chain activity stimulated by Ca²⁺ load. We used this method to investigate cellular signal transduction in different cancer cells and revealed rapid intracellular Ca²⁺ flow, unidirectional intercellular signaling processes, and neuronal signaling activity, which demonstrated the potential and convenience of the method for routine Ca²⁺ research.

The Role of Vitamin D and Sunlight Incidence in Cancer

BACKGROUND

Vitamin D (VD) deficiency affects individuals of different ages in many countries. VD deficiency may be related to several diseases, including cancer.

OBJECTIVE

This study aimed to review the relationship between VD deficiency and cancer.

METHODS

We describe the proteins involved in cancer pathogenesis and how those proteins can be influenced by VD deficiency. We also investigated a relationship between cancer death rate and solar radiation.

RESULTS

We found an increased bladder cancer, breast cancer, colon-rectum cancer, lung cancer, oesophagus cancer, oral cancer, ovary cancer, pancreas cancer, skin cancer and stomach cancer death rate in countries with low sunlight. It was also observed that amyloid precursor protein, ryanodine receptor, mammalian target of rapamycin complex 1, and receptor for advanced glycation end products are associated with a worse prognosis in cancer. While the Klotho protein and VD receptor are associated with a better prognosis in the disease. Nfr2 is associated with both worse and better prognosis in cancer.

CONCLUSION

The literature suggests that VD deficiency might be involved in cancer progression. According to sunlight data, we can conclude that countries with low average sunlight have high cancers death rate. New studies involving transcriptional and genomic data in combination with VD measurement in long-term experiments are required to establish new relationships between VD and cancer.

Type 3 IP3 receptors: The chameleon in cancer

Inositol 1,4,5-trisphosphate (IP₃) receptors (IP₃Rs), intracellular calcium (Ca²⁺) release channels, fulfill key functions in cell death and survival processes, whose dysregulation contributes to oncogenesis. This is essentially due to the presence of IP₃Rs in microdomains of the endoplasmic reticulum (ER) in close proximity to the mitochondria. As such, IP₃Rs enable efficient Ca²⁺ transfers from the ER to the mitochondria, thus regulating metabolism and cell fate. This review focuses on one of the three IP₃R isoforms, the type 3 IP₃R (IP₃R3), which is linked to proapoptotic ER-mitochondrial Ca²⁺ transfers. Alterations in IP₃R3 expression have been highlighted in numerous cancer types, leading to dysregulations of Ca²⁺ signaling and cellular functions. However, the outcome of IP₃R3-mediated Ca²⁺ transfers for mitochondrial function is complex with opposing effects on oncogenesis. IP₃R3 can either suppress cancer by promoting cell death and cellular senescence or support cancer by driving metabolism, anabolic processes, cell cycle progression, proliferation and invasion. The aim of this review is to provide an overview of IP₃R3 dysregulations in cancer and describe how such dysregulations alter critical cellular processes such as proliferation or cell death and survival. Here, we pose that the IP₃R3 isoform is not only linked to proapoptotic ER-mitochondrial Ca²⁺ transfers but might also be involved in prosurvival signaling.

Calcium transport and signalling in breast cancer: Functional and prognostic significance

Comprised of a complex network of numerous intertwining pathways, the Ca²⁺ signalling nexus is an essential mediator of many normal cellular activities. Like many other such functions, the normal physiological activity of Ca²⁺ signalling is frequently co-opted and reshaped in cases of breast cancer, creating a potent oncogenic drive within the affected cell population. Such modifications can occur within pathways mediating either Ca²⁺ import (e.g. TRP channels, ORAI-STIM1) or Ca²⁺ export (e.g. PMCA), indicating that both increases and decreases within cellular Ca²⁺ levels have the potential to increase the malignant potential of a cell. Increased understanding of these pathways may offer clinical benefit in terms of both prognosis and treatment; patient survival has been linked to expression levels of certain Ca²⁺ transport proteins, whilst selective targeting of these factors with novel anti-cancer agents has demonstrated a variety of anti-tumour effects in in vitro studies. In addition, the activity of several Ca²⁺ signalling pathways has been shown to influence chemotherapy response, suggesting that a synergistic approach coupling traditional chemotherapy with Ca²⁺ targeting agents may also improve patient outcome. As such, targeted modulation of these pathways represents a novel approach in precision medicine and breast cancer therapy.

GLS2 is protumorigenic in breast cancers

Many types of cancers have a well-established dependence on glutamine metabolism to support survival and growth, a process linked to glutaminase 1 (GLS) isoforms. Conversely, GLS2 variants often have tumor-suppressing activity. Triple-negative (TN) breast cancer (testing negative for estrogen, progesterone, and Her2 receptors) has elevated GLS protein levels and reportedly depends on exogenous glutamine and GLS activity for survival. Despite having high GLS levels, we verified that several breast cancer cells (including TN cells) express endogenous GLS2, defying its role as a bona fide tumor suppressor. Moreover, ectopic GLS2 expression rescued cell proliferation, TCA anaplerosis, redox balance, and mitochondrial function after GLS inhibition by the small molecule currently in clinical trials CB-839 or GLS knockdown of GLS-dependent cell lines. In several cell lines, GLS2 knockdown decreased cell proliferation and glutamine-linked metabolic phenotypes. Strikingly, long-term treatment of TN cells with another GLS-exclusive inhibitor bis-2'-(5-phenylacetamide-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES) selected for a drug-resistant population with increased endogenous GLS2 and restored proliferative capacity. GLS2 was linked to enhanced in vitro cell migration and invasion, mesenchymal markers (through the ERK-ZEB1-vimentin axis under certain conditions) and in vivo lung metastasis. Of concern, GLS2 amplification or overexpression is linked to an overall, disease-free and distant metastasis-free worse survival prognosis in breast cancer. Altogether, these data establish an unforeseen role of GLS2 in sustaining tumor proliferation and underlying metastasis in breast cancer and provide an initial framework for exploring GLS2 as a novel therapeutic target.

The Calcium-Signaling Toolkit in Cancer: Remodeling and Targeting

Processes that are important in cancer progression, such as sustained cell growth, invasion to other organs, and resistance to cell death inducers, have a clear overlap with pathways regulated by Ca²⁺ signaling. It is therefore not surprising that proteins important in Ca²⁺ signaling, sometimes referred to as the "Ca²⁺ signaling toolkit," can contribute to cancer cell proliferation and invasiveness, and the ability of agents to induce cancer cell death. Ca²⁺ signaling is also critical in other aspects of cancer progression, including events in the tumor microenvironment and processes involved in the acquisition of resistance to anticancer therapies. This review will consider the role of Ca²⁺ signaling in tumor progression and highlight areas in which a better understanding of the interplay between the Ca²⁺-signaling toolkit and tumorigenesis is still required.

ER Ca2+ release and store-operated Ca2+ entry - partners in crime or independent actors in oncogenic transformation?

Ca²⁺ is a pleiotropic messenger that controls life and death decisions from fertilisation until death. Cellular Ca²⁺ handling mechanisms show plasticity and are remodelled throughout life to meet the changing needs of the cell. In turn, as the demands on a cell alter, for example through a change in its niche environment or its functional requirements, Ca²⁺ handling systems may be targeted to sustain the remodelled cellular state. Nowhere is this more apparent than in cancer. Oncogenic transformation is a multi-stage process during which normal cells become progressively differentiated towards a cancerous state that is principally associated with enhanced proliferation and avoidance of death. Ca²⁺ signalling is intimately involved in almost all aspects of the life of a transformed cell and alterations in Ca²⁺ handling have been observed in cancer. Moreover, this remodelling of Ca²⁺ signalling pathways is also required in some cases to sustain the transformed phenotype. As such, Ca²⁺ handling is hijacked by oncogenic processes to deliver and maintain the transformed phenotype. Central to generation of intracellular Ca²⁺ signals is the release of Ca²⁺ from the endoplasmic reticulum intracellular (ER) Ca²⁺ store via inositol 1,4,5-trisphosphate receptors (InsP₃Rs). Upon depletion of ER Ca²⁺, store-operated Ca²⁺ entry (SOCE) across the plasma membrane occurs via STIM-gated Orai channels. SOCE serves to both replenish stores but also sustain Ca²⁺ signalling events. Here, we will discuss the role and regulation of these two signalling pathways and their interplay in oncogenic transformation.

Morphological State Transition Dynamics in EGF-Induced Epithelial to Mesenchymal Transition

Epithelial to Mesenchymal Transition (EMT) is a multi-state process. Here, we investigated phenotypic state transition dynamics of Epidermal Growth Factor (EGF)-induced EMT in a breast cancer cell line MDA-MB-468. We have defined phenotypic states of these cells in terms of their morphologies and have shown that these cells have three distinct morphological states-cobble, spindle, and circular. The spindle and circular states are the migratory phenotypes. Using quantitative image analysis and mathematical modeling, we have deciphered state transition trajectories in different experimental conditions. This analysis shows that the phenotypic state transition during EGF-induced EMT in these cells is reversible, and depends upon the dose of EGF and level of phosphorylation of the EGF receptor (EGFR). The dominant reversible state transition trajectory in this system was cobble to circular to spindle to cobble. We have observed that there exists an ultrasensitive on/off switch involving phospho-EGFR that decides the transition of cells in and out of the circular state. In general, our observations can be explained by the conventional quasi-potential landscape model for phenotypic state transition. As an alternative to this model, we have proposed a simpler discretized energy-level model to explain the observed state transition dynamics.

Somatic mutations and promotor methylation of the ryanodine receptor 2 is a common event in the pathogenesis of head and neck cancer

Genomic sequencing projects unraveled the mutational landscape of head and neck squamous cell carcinoma (HNSCC) and provided a comprehensive catalog of somatic mutations. However, the limited number of significant cancer-related genes obtained so far only partially explains the biological complexity of HNSCC and hampers the development of novel diagnostic biomarkers and therapeutic targets. We pursued a multiscale omics approach based on whole-exome sequencing, global DNA methylation and gene expression profiling data derived from tumor samples of the HIPO-HNC cohort (n = 87), and confirmed new findings with datasets from The Cancer Genome Atlas (TCGA). Promoter methylation was confirmed by MassARRAY analysis and protein expression was assessed by immunohistochemistry and immunofluorescence staining. We discovered a set of cancer-related genes with frequent somatic mutations and high frequency of promoter methylation. This included the ryanodine receptor 2 (RYR2), which showed variable promoter methylation and expression in both tumor samples and cell lines. Immunohistochemical staining of tissue sections unraveled a gradual loss of RYR2 expression from normal mucosa via dysplastic lesion to invasive cancer and indicated that reduced RYR2 expression in adjacent tissue and precancerous lesions might serve as risk factor for unfavorable prognosis and upcoming malignant conversion. In summary, our data indicate that impaired RYR2 function by either somatic mutation or epigenetic silencing is a common event in HNSCC pathogenesis. Detection of RYR2 expression and/or promoter methylation might enable risk assessment for malignant conversion of dysplastic lesions.

Pharmacological modulation of mitochondrial ion channels

The field of mitochondrial ion channels has undergone a rapid development during the last three decades, due to the molecular identification of some of the channels residing in the outer and inner membranes. Relevant information about the function of these channels in physiological and pathological settings was gained thanks to genetic models for a few, mitochondria-specific channels. However, many ion channels have multiple localizations within the cell, hampering a clear-cut determination of their function by pharmacological means. The present review summarizes our current knowledge about the ins and outs of mitochondrial ion channels, with special focus on the channels that have received much attention in recent years, namely, the voltage-dependent anion channels, the permeability transition pore (also called mitochondrial megachannel), the mitochondrial calcium uniporter and some of the inner membrane-located potassium channels. In addition, possible strategies to overcome the difficulties of specifically targeting mitochondrial channels versus their counterparts active in other membranes are discussed, as well as the possibilities of modulating channel function by small peptides that compete for binding with protein interacting partners. Altogether, these promising tools along with large-scale chemical screenings set up to identify new, specific channel modulators will hopefully allow us to pinpoint the actual function of most mitochondrial ion channels in the near future and to pharmacologically affect important pathologies in which they are involved, such as neurodegeneration, ischaemic damage and cancer. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

Selected Golgi-Localized Proteins and Carcinogenesis: What Do We Know?

The role of the Golgi apparatus in carcinogenesis still remains unclear. A number of structural and functional cis-, medial-, and trans-Golgi proteins as well as a complexity of metabolic pathways which they mediate may indicate a central role of the Golgi apparatus in the development and progression of cancer. Pleiotropy of cellular function of the Golgi apparatus makes it a "metabolic heart" or a relay station of a cell, which combines multiple signaling pathways involved in carcinogenesis. Therefore, any damage to or structural abnormality of the Golgi apparatus, causing its fragmentation and/or biochemical dysregulation, results in an up- or downregulation of signaling pathways and may in turn promote tumor progression, as well as local nodal and distant metastases. Three alternative or parallel models of spatial and functional Golgi organization within tumor cells were proposed: (1) compacted Golgi structure, (2) normal Golgi structure with its increased activity, and (3) the Golgi fragmentation with ministacks formation. Regardless of the assumed model, the increased activity of oncogenesis initiators and promoters with inhibition of suppressor proteins results in an increased cell motility and migration, increased angiogenesis, significantly activated trafficking kinetics, proliferation, EMT induction, decreased susceptibility to apoptosis-inducing factors, and modulating immune response to tumor cell antigens. Eventually, this will lead to the increased metastatic potential of cancer cells and an increased risk of lymph node and distant metastases. This chapter provided an overview of the current state of knowledge of selected Golgi proteins, their role in cytophysiology as well as potential involvement in tumorigenesis.

Jiedu Sangen Decoction Inhibits Migration and Invasion of Colon Cancer SW480 Cells via Suppressing Epithelial Mesenchymal Transition

Jiedu Sangen Decoction (JSD), a traditional Chinese medicine (TCM) formula, has been widely used in China to treat gastrointestinal cancer, especially as an adjuvant therapy in colorectal cancer (CRC) patients. This study aimed to evaluate the efficacy of JSD and Jiedu Sangen aqueous extract (JSAE) in colon cancer cells and explored the underlining mechanisms by cytotoxicity assay, scratch assay, transwell migration assay, matrigel invasion assay, confocal laser scanning microscopy, and western blot analysis. We demonstrated that JSAE inhibited the growth of colon cancer SW480 cells in a dose-dependent manner and JSAE repressed cancer cell migration and invasion. Furthermore, epithelial mesenchymal transition (EMT) was reversed by JSAE via enhancing E-cadherin expression and attenuating protein levels of EMT promoting factors such as N-cadherin, Slug, and ZEB1. These findings provided the first experimental evidence confirming the efficacy of JSAE in repressing invasion and metastasis of CRC and paving a way for the broader use of JSD in clinic.

The calcium channel proteins ORAI3 and STIM1 mediate TGF-β induced Snai1 expression

Calcium influx into cells via plasma membrane protein channels is tightly regulated to maintain cellular homeostasis. Calcium channel proteins in the plasma membrane and endoplasmic reticulum have been linked to cancer, specifically during the epithelial-mesenchymal transition (EMT), a cell state transition process implicated in both cancer cell migration and drug resistance. The transcription factor SNAI1 (SNAIL) is upregulated during EMT and is responsible for gene expression changes associated with EMT, but the calcium channels required for Snai1 expression remain unknown. In this study, we show that blocking store-operated calcium entry (SOCE) with 2-aminoethoxydiphenylborane (2APB) reduces cell migration but, paradoxically, increases the level of TGF-β dependent Snai1 gene activation. We determined that this increased Snai1 transcription involves signaling through the AKT pathway and subsequent binding of NF-κB (p65) at the Snai1 promoter in response to TGF-β. We also demonstrated that the calcium channel protein ORAI3 and the stromal interaction molecule 1 (STIM1) are required for TGF-β dependent Snai1 transcription. These results suggest that calcium channels differentially regulate cell migration and Snai1 transcription, indicating that each of these steps could be targeted to ensure complete blockade of cancer progression.

The role of the mitochondrial calcium uniporter (MCU) complex in cancer

The important role of mitochondria in cancer biology is gaining momentum. With their regulation of cell survival, metabolism, basic cell building blocks, and immunity, among other functions, mitochondria affect not only cancer progression but also the response and resistance to current treatments. Calcium ions are constantly shuttled in and out of mitochondria; thus, playing an important role in the regulation of various cellular processes. The mitochondrial calcium uniporter (MCU) channel and its associated regulators transport calcium across the inner mitochondrial membrane to the mitochondrial matrix. Due to this central role and the capacity to affect cell behavior and fate, the MCU complex is being investigated in different cancers and cancer-related conditions. Here, we review current knowledge on the role of the MCU complex in multiple cancer types and models; we also provide a perspective for future research and clinical considerations.

TGFβ-induced epithelial-to-mesenchymal transition in prostate cancer cells is mediated via TRPM7 expression

Growth factors, such as the transforming growth factor beta (TGFβ), play an important role in promoting metastasis of prostate cancer, thus understanding how TGFβ could induce prostate cancer cell migration may enable us to develop targeted strategies for treatment of advanced metastatic prostate cancer. To more clearly define the mechanism(s) involved in prostate cancer cell migration, we undertook a series of studies utilizing non‐malignant prostate epithelial cells RWPE1 and prostate cancer DU145 and PC3 cells. Our studies show that increased cell migration was observed in prostate cancer cells, which was mediated through epithelial‐to‐mesenchymal transition (EMT). Importantly, addition of Mg²⁺, but not Ca²⁺, increased cell migration. Furthermore, TRPM7 expression, which functions as an Mg²⁺ influx channel, was also increased in prostate cancer cells. Inhibition of TRPM7 currents by 2‐APB, significantly blocked cell migration in both DU145 and PC3 cells. Addition of growth factor TGFβ showed a further increase in cell migration, which was again blocked by the addition of 2‐APB. Importantly, TGFβ addition also significantly increased TRPM7 expression and function, and silencing of TRPM7 negated TGFβ‐induced cell migration along with a decrease in EMT markers showing loss of cell adhesion. Furthermore, resveratrol, which decreases prostate cancer cell migration, inhibited TRPM7 expression and function including TGFβ‐induced cell migration and activation of TRPM7 function. Together, these results suggest that Mg²⁺ influx via TRPM7 promotes cell migration by inducing EMT in prostate cancer cells and resveratrol negatively modulates TRPM7 function thereby inhibiting prostate cancer metastasis.

FGF4 induces epithelial-mesenchymal transition by inducing store-operated calcium entry in lung adenocarcinoma

Several fibroblast growth factor (FGF) isoforms act to stimulate epithelial-mesenchymal transition (EMT) during cancer progression. FGF4 and FGF7 are two ligands of FGF receptor 2 (FGFR2). Using two lung adenocarcinoma (ADC) cell lines, A549 and H1299, we showed that FGF4, but not FGF7, altered cell morphology, promoted EMT-associated protein expression, and enhanced cell proliferation, migration/invasion and colony initiation. In addition, FGF4 increased store-operated calcium entry (SOCE) and expression of the calcium signal-associated protein Orai1. The SOCE inhibitor 2,5-di-tert-butylhydroquinone (BHQ) or Orai1 knockdown reversed all of the EMT-promoting effects of FGF4. BHQ also inhibited FGF4-induced EMT in a mouse xenograft model. Finally, 60 human lung ADC samples and 21 sets of matched specimens (primary and metastatic foci in lymph nodes from one patient) were used to confirm the clinicopathologic significance of FGF4 and its correlation with E-cadherin, Vimentin and Orai1 expression. Our study thus shows that FGF4 induces EMT by elevating SOCE in lung ADC.

The current status and perspectives regarding the clinical implication of intracellular calcium in breast cancer

Calcium ions (Ca²⁺ ) act as second messengers in intracellular signaling. Ca²⁺ pumps, channels, sensors, and calcium binding proteins, regulate the concentrations of intracellular Ca²⁺ as a key regulator of important cellular processes such as gene expression, proliferation, differentiation, DNA repair, apoptosis, metastasis, and hormone secretion. Intracellular Ca²⁺ also influences the functions of several organelles, that include: the endoplasmic reticulum, mitochondria, the Golgi, and cell membrane both in normal and breast cancer cells. In breast cancer, the disruption of intracellular: Ca²⁺ homeostasis may cause tumor progression by affecting key factors/pathways including phospholipase C (PLC), inositol 1,4,5-trisphosphate (IP3), calmodulin (CaM), nuclear factor of activated T-cells (NFAT), calpain, calmodulin-dependent protein kinase II (CaMKII), mitogen-activated protein kinase (MAPK), epithelial-mesenchymal transition (EMT), vascular endothelial growth factor (VEGF), poly (ADP-Ribose) polymerase-1 (PARP1), estrogen, and estrogen receptor. Because the foregoing molecules play crucial roles in breast cancer, the factors/pathways influencing intracellular Ca²⁺ concentrations are putative targets for cancer treatment, using drugs such as Mephebrindole, Tilapia piscidin 4, Nifetepimine, Paricalcitol, and Prednisolone. We have explored the factors/pathways which are related to breast cancer and Ca²⁺ homeostasis and signaling in this review, and also discussed their potential as biomarkers for breast cancer staging, prognosis, and therapy.

An early-screening biomarker of endometrial carcinoma: NGAL is associated with epithelio-mesenchymal transition

neutrophilgelatinase-associated lipocalin is currently one of the most interesting and enigmatic proteins involved in the development of malignancies. In this study, we found that the expression of neutrophilgelatinase-associated lipocalin was up-regulated in endometrial cancer tissues and cell lines, significantly increased in early-grade ones, suggesting it may serve as a biomarker for early-stage screening for endometrial carcinoma. Moreover, neutrophilgelatinase-associated lipocalin was up-regulated in Ishikawa cells under going epithelio-mesenchymal transition induced by epidermal growth factor (5 ng/ml). Up-regulation of neutrophilgelatinase-associated lipocalin may correlate with the down-regulation of E-cadherin expression, up-regulation of Vimentin expression, enhanced cell migration, invasion and proliferation, which are the typical hallmarks of epithelio-mesenchymal transition processes. neutrophilgelatinase-associated lipocalin may play a dual role during tumorigenetic and developmental processes of endometrial carcinoma. These results suggested neutrophilgelatinase-associated lipocalin to be a potential molecular target in the early diagnosis and treatment of endometrial carcinoma. Further studies are warranted to clarify the molecular mechanisms behind the expression and function of neutrophilgelatinase-associated lipocalin and epithelio-mesenchymal transition.

Overexpression of TrpC5 promotes tumor metastasis via the HIF-1α-Twist signaling pathway in colon cancer

In cancer cells, intracellular Ca²⁺ homeostasis is altered, and this is involved in tumor initiation, progression, and metastasis. However, little is known about the underlying mechanisms. Here, we report that transient receptor potential channel 5 (TrpC5), a receptor-activated non-selective Ca²⁺ channel, is correlated with tumor metastasis in colon cancer patients. Moreover, in colon cancer cells, overexpression of TrpC5 caused a robust rise in the concentration of ([Ca²⁺]_i), decreased E-cadherin, and increased mesenchymal biomarker expression, then promoted cell migration, invasion, and proliferation. Interestingly, we found that TrpC5 mediated hypoxia-inducible factor 1α (HIF-1α) expression, activating Twist to promote the epithelial-mesenchymal transition (EMT). Notably, patients with high expression of TrpC5 displayed poorer overall and metastasis-free survival. Taken together, our findings demonstrate that TrpC5 induces the EMT through the HIF-1α-Twist signaling pathway to promote tumor metastasis in colon cancer.

Mechanisms underlying effect of the mycotoxin cytochalasin B on induction of cytotoxicity, modulation of cell cycle, Ca2+ homeostasis and ROS production in human breast cells

Cytochalasin B, a cell-permeable mycotoxin isolated from the fungus Phoma spp., shows a wide range of biological effects, among which its potent antitumor activity has raised great interests in different models. However, the cytotoxic activity of cytochalasin B and its underlying mechanisms have not been elucidated in breast cells. This study examined the effect of cytochalasin B on MCF 10A human breast epithelial cells and ZR-75-1 human breast cancer cells. Cytochalasin B (10-20μM) concentration-dependently induced cytotoxicity, cell cycle arrest, and [Ca²⁺]_i rises in ZR-75-1 cells but not in MCF 10A cells. In ZR-75-1 cells, cytochalasin B triggered G2/M phase arrest through the modulation of CDK1, cyclin B1, p53, p27 and p21 expressions. The Ca²⁺ signal response induced by cytochalasin B was reduced by removing extracellular Ca²⁺ and was inhibited by the store-operated Ca²⁺ channel blocker 2-APB and SKF96365. In Ca²⁺-free medium, cytochalasin B induced Ca²⁺ release through thapsigargin-sensitive endoplasmic reticulum stores. Moreover, cytochalasin B increased H₂O₂ levels but reduced GSH levels. The apoptotic effects evoked by cytochalasin B were partially inhibited by prechelating cytosolic Ca²⁺ with BAPTA-AM and the antioxidant NAC. Together, in ZR-75-1 cells but not in MCF 10A cells, cytochalasin B activated Ca²⁺-associated mitochondrial apoptotic pathways that involved G2/M phase arrest and ROS signaling. Furthermore, cytochalasin B induced [Ca²⁺]_i rises by releasing Ca²⁺ from the endoplasmic reticulum and causing Ca²⁺ influx through 2-APB or SKF96365-sensitive store-operated Ca²⁺ entry. Our findings provide new insights into the possible application of cytochalasin B in human breast cancer therapy.

Impact of intracellular ion channels on cancer development and progression

Cancer research is nowadays focused on the identification of possible new targets in order to try to develop new drugs for curing untreatable tumors. Ion channels have emerged as "oncogenic" proteins, since they have an aberrant expression in cancers compared to normal tissues and contribute to several hallmarks of cancer, such as metabolic re-programming, limitless proliferative potential, apoptosis-resistance, stimulation of neo-angiogenesis as well as cell migration and invasiveness. In recent years, not only the plasma membrane but also intracellular channels and transporters have arisen as oncological targets and were proposed to be associated with tumorigenesis. Therefore, the research is currently focusing on understanding the possible role of intracellular ion channels in cancer development and progression on one hand and, on the other, on developing new possible drugs able to modulate the expression and/or activity of these channels. In a few cases, the efficacy of channel-targeting drugs in reducing tumors has already been demonstrated in vivo in preclinical mouse models.

Selective Vulnerability of Cancer Cells by Inhibition of Ca(2+) Transfer from Endoplasmic Reticulum to Mitochondria

In the absence of low-level ER-to-mitochondrial Ca(2+) transfer, ATP levels fall, and AMPK-dependent, mTOR-independent autophagy is induced as an essential survival mechanism in many cell types. Here, we demonstrate that tumorigenic cancer cell lines, transformed primary human fibroblasts, and tumors in vivo respond similarly but that autophagy is insufficient for survival, and cancer cells die while their normal counterparts are spared. Cancer cell death is due to compromised bioenergetics that can be rescued with metabolic substrates or nucleotides and caused by necrosis associated with mitotic catastrophe during their proliferation. Our findings reveal an unexpected dependency on constitutive Ca(2+) transfer to mitochondria for viability of tumorigenic cells and suggest that mitochondrial Ca(2+) addiction is a feature of cancer cells.

Low spinophilin expression enhances aggressive biological behavior of breast cancer

Spinophilin, a putative tumor suppressor gene, has been shown to be involved in the pathogenesis of certain types of cancer, but its role has never been systematically explored in breast cancer. In this study, we determined for the first time the expression pattern of spinophilin in human breast cancer molecular subtypes (n = 489) and correlated it with survival (n = 921). We stably reduced spinophilin expression in breast cancer cells and measured effects on cellular growth, apoptosis, anchorage-independent growth, migration, invasion and self-renewal capacity in vitro and metastases formation in vivo. Microarray profiling was used to determine the most abundantly expressed genes in spinophilin-silenced breast cancer cells. Spinophilin expression was significantly lower in basal-like breast cancer (p<0.001) and an independent poor prognostic factor in breast cancer patients (hazard ratio = 1.93, 95% confidence interval: 1.24-3.03; p = 0.004) A reduction of spinophilin levels increased cellular growth in breast cancer cells (p<0.05), without influencing activation of apoptosis. Anchorage-independent growth, migration and self-renewal capacity in vitro and metastatic potential in vivo were also significantly increased in spinophilin-silenced cells (p<0.05). Finally, we identified several differentially expressed genes in spinophilin-silenced cells. According to our data, low levels of spinophilin are associated with aggressive behavior of breast cancer.

Male infertility in mice lacking the store-operated Ca(2+) channel Orai1

Store-operated calcium entry (SOCE) is an important Ca(2+) influx pathway in somatic cells. In addition to maintaining endoplasmic reticulum (ER) Ca(2+) stores, Ca(2+) entry through store-operated channels regulates essential signaling pathways in numerous cell types. Patients with mutations in the store-operated channel subunit ORAI1 exhibit defects in store-operated Ca(2+) influx, along with severe immunodeficiency, congenital myopathy and ectodermal dysplasia. However, little is known about the functional role of ORAI1 in germ cells and reproductive function in mice, or in men, since men with loss-of-function or null mutations in ORAI1 rarely survive to reproductive age. In this study, we investigated the role of ORAI1 in male reproductive function. We reveal that Orai1(-/-) male mice are sterile and have severe defects in spermatogenesis, with prominent deficiencies in mid- to late-stage elongating spermatid development. These studies establish an essential in vivo role for store-operated ORAI1 channels in male reproductive function and identify these channels as potential non-steroidal regulators of male fertility.

ER functions of oncogenes and tumor suppressors: Modulators of intracellular Ca(2+) signaling

Intracellular Ca(2+) signals that arise from the endoplasmic reticulum (ER), the major intracellular Ca(2+)-storage organelle, impact several mitochondrial functions and dictate cell survival and cell death processes. Furthermore, alterations in Ca(2+) signaling in cancer cells promote survival and establish a high tolerance towards cell stress and damage, so that the on-going oncogenic stress does not result in the activation of cell death. Over the last years, the mechanisms underlying these oncogenic alterations in Ca(2+) signaling have started to emerge. An important aspect of this is the identification of several major oncogenes, including Bcl-2, Bcl-XL, Mcl-1, PKB/Akt, and Ras, and tumor suppressors, such as p53, PTEN, PML, BRCA1, and Beclin 1, as direct and critical regulators of Ca(2+)-transport systems located at the ER membranes, including IP3 receptors and SERCA Ca(2+) pumps. In this way, these proteins execute part of their function by controlling the ER-mitochondrial Ca(2+) fluxes, favoring either survival (oncogenes) or cell death (tumor suppressors). Oncogenic mutations, gene deletions or amplifications alter the expression and/or function of these proteins, thereby changing the delicate balance between oncogenes and tumor suppressors, impacting oncogenesis and favoring malignant cell function and behavior. In this review, we provided an integrated overview of the impact of the major oncogenes and tumor suppressors, often altered in cancer cells, on Ca(2+) signaling from the ER Ca(2+) stores. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen.

The Roles of Mitochondrial Cation Channels Under Physiological Conditions and in Cancer

Bioenergetics has become central to our understanding of pathological mechanisms as well as the development of new therapeutic strategies and as a tool for gauging disease progression in neurodegeneration, diabetes, cancer, and cardiovascular disease. The view is emerging that inner mitochondrial membrane (IMM) cation channels have a profound effect on mitochondrial function and, consequently, on the metabolic state and survival of the whole cell. Since disruption of the sustained integrity of mitochondria is strongly linked to human disease, pharmacological intervention offers a new perspective concerning neurodegenerative and cardiovascular diseases as well as cancer. This review summarizes our current knowledge regarding IMM cation channels and their roles under physiological conditions as well as in cancer, with special emphasis on potassium channels and the mammalian mitochondrial calcium uniporter.

The effect of TGF-beta-induced epithelial-mesenchymal transition on the expression of intracellular calcium-handling proteins in T47D and MCF-7 human breast cancer cells

The contribution of Ca(2+) in TGF-β-induced EMT is poorly understood. We aimed to confirm the effect of TGF-β on the gene expression of intracellular calcium-handling proteins and to investigate the potential underlying mechanisms in TGF-β-induced EMT. T47D and MCF-7 cells were cultured in vitro and treated with TGF-β. The mRNA expression of EMT marker genes and intracellular calcium-handling proteins were quantified by qRT-PCR. qRT-PCR and Western blot analysis results verified the changes of EMT marker gene expression. Furthermore, we found that TGF-β induced cell morphological changes significantly with an increase of cell surface area and cell length. These results indicated that TGF-β induced EMT. The mRNA expression levels of SPCA1, SPCA2 and MCU were not influenced by TGF-β treatment, while NCX1 expression was decreased in T47D cells. In addition, the mRNA levels of SERCAs and IP3Rs were significantly changed due to TGF-β-induced EMT. The TGF-β-treated T47D cells exhibited markedly greater response to ATP than the control cells, and the descent velocity of cytosolic calcium concentration was faster in TGF-β-treated cells than in control cells. This is the first report to demonstrate that TGF-β-induced EMT in human breast cancer cells is associated with alterations in endoplasmic reticulum calcium homeostasis.

Stress responses from the endoplasmic reticulum in cancer

The endoplasmic reticulum (ER) is a dynamic organelle that is essential for multiple cellular functions. During cellular stress conditions, including nutrient deprivation and dysregulation of protein synthesis, unfolded/misfolded proteins accumulate in the ER lumen, resulting in activation of the unfolded protein response (UPR). The UPR also contributes to the regulation of various intracellular signaling pathways such as calcium signaling and lipid signaling. More recently, the mitochondria-associated ER membrane (MAM), which is a site of close contact between the ER and mitochondria, has been shown to function as a platform for various intracellular stress responses including apoptotic signaling, inflammatory signaling, the autophagic response, and the UPR. Interestingly, in cancer, these signaling pathways from the ER are often dysregulated, contributing to cancer cell metabolism. Thus, the signaling pathway from the ER may be a novel therapeutic target for various cancers. In this review, we discuss recent research on the roles of stress responses from the ER, including the MAM.

Proteomic analysis of the effect of extracellular calcium ions on human mesenchymal stem cells: Implications for bone tissue engineering

Human mesenchymal stem cells-bone marrow (BM-hMSCs) are considered as the most suitable seed cells for bone tissue engineering. Calcium ions (Ca(2+)) forms an important component of a number of commercial bone substitutes and support materials. For efficient bone tissue engineering, it is crucial to explore the effect of extracellular Ca(2+) on the growth and differentiation of BM-hMSCs, and to understand their molecular mechanisms. Therefore, in the present study, BM-hMSCs were cultivated in serum free growth medium or serum free growth medium with additional 4 or 6mM Ca(2+) for 3weeks, following which, the proliferation and osteoblastic differentiation of these cells were evaluated. Differentially expressed proteins were established using iTRAQ labeling coupled with nano-LC-MS/MS. Our data revealed that Ca(2+) significantly promoted the proliferation of BM-hMSCs in the early stage. Furthermore, Ca(2+) showed osteoinduction properties. MAPKs signaling pathway might participate in the osteogenic differentiation of BM-hMSCs caused by Ca(2+). Certain newly found proteins could be potentially important for the osteogenic differentiation of BM-hMSCs and may be associated with osteogenesis.