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1.
Decoding the Phosphatase Code: Regulation of Cell Proliferation by Calcineurin.
Masaki, T, Shimada, M
International journal of molecular sciences. 2022;(3)
Abstract
Calcineurin, a calcium-dependent serine/threonine phosphatase, integrates the alterations in intracellular calcium levels into downstream signaling pathways by regulating the phosphorylation states of several targets. Intracellular Ca2+ is essential for normal cellular physiology and cell cycle progression at certain critical stages of the cell cycle. Recently, it was reported that calcineurin is activated in a variety of cancers. Given that abnormalities in calcineurin signaling can lead to malignant growth and cancer, the calcineurin signaling pathway could be a potential target for cancer treatment. For example, NFAT, a typical substrate of calcineurin, activates the genes that promote cell proliferation. Furthermore, cyclin D1 and estrogen receptors are dephosphorylated and stabilized by calcineurin, leading to cell proliferation. In this review, we focus on the cell proliferative functions and regulatory mechanisms of calcineurin and summarize the various substrates of calcineurin. We also describe recent advances regarding dysregulation of the calcineurin activity in cancer cells. We hope that this review will provide new insights into the potential role of calcineurin in cancer development.
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2.
Serum calcium-phosphorus product for predicting the risk of osteoporotic vertebral compression fractures in elderly patients: a retrospective observational study.
Ying, P, Gu, M, Jiang, X, Xu, Y, Tong, L, Xue, Y, Wang, Q, Huang, Z, Ding, W, Dai, X
Journal of orthopaedic surgery and research. 2022;(1):57
Abstract
BACKGROUND This study retrospectively analyzed and evaluated the potential correlations of serum calcium, serum phosphorus, and calcium-phosphorus product (Ca-P product) with the incidence of osteoporotic vertebral compression fractures (OVCFs), with the aim of exploring whether the Ca-P product can be used as a serological indicator to predict the risk of OVCFs. METHODS This study randomly enrolled 400 elderly patients in our hospital with OVCFs and 400 patients with hip and knee arthroplasty due to femoral head necrosis or osteoarthritis from August 2013 to April 2021. Age, sex, past medical history, and admission biochemical indicators, including albumin, blood urea nitrogen, serum creatinine, serum calcium and serum phosphorus, were collected for statistical analysis. RESULTS Albumin, serum calcium, serum phosphorus, Ca-P product, corrected serum calcium and corrected Ca-P product were lower in the OVCF group than in the non-OVCF group (P < 0.05). Multivariate logistic regression analysis showed that low values of serum calcium, serum phosphorus, Ca-P product, corrected blood calcium, and corrected Ca-P product can all be risk factors for OVCF. The ROC curve showed that the Ca-P product and corrected Ca-P product were effective in predicting the risk of OVCFs. The predictive value of the Ca-P product was the best; the cutoff point was 29.88, the sensitivity was 0.72 and the specificity was 0.62. The cutoff point of the corrected Ca-P product was 30.50, the sensitivity was 0.74, and the specificity was 0.62. CONCLUSION The Ca-P product and corrected Ca-P product can be used as serological indicators to predict the risk of OVCFs in elderly individuals. Early clinical interventions targeting this risk factor can further reduce the risk of OVCFs. Also, timely and regular testing of the serum calcium and phosphorus level is recommended and encouraged for this group of people.
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3.
Insight of the role of mitochondrial calcium homeostasis in hepatic insulin resistance.
Dong, Z, Yao, X
Mitochondrion. 2022;:128-138
Abstract
Due to the rapid rise in the prevalence of chronic metabolic disease, more and more clinicians and basic medical researchers focus their eyesight on insulin resistance (IR), an early and central event of metabolic diseases. The occurrence and development of IR are primarily caused by excessive energy intake and reduced energy consumption. Liver is the central organ that controls glucose homeostasis, playing a considerable role in systemic IR. Decreased capacity of oxidative metabolism and mitochondrial dysfunction are being blamed as the direct reason for the development of IR. Mitochondrial Ca2+ plays a fundamental role in maintaining proper mitochondrial function and redox stability. The maintaining of mitochondrial Ca2+ homeostasis requires the cooperation of ion channels in the inner and outer membrane of mitochondria, such as mitochondrial calcium uniporter complex (MCUC) and voltage-dependent anion channels (VDACs). In addition, the crosstalk between the endoplasmic reticulum (ER), lysosome and plasma membrane with mitochondria is also significant for mitochondrial calcium homeostasis, which is responsible for an efficient network of cellular Ca2+ signaling. Here, we review the recent progression in the research about the regulation factors for mitochondrial Ca2+ and how the dysregulation of mitochondrial Ca2+ homeostasis is involved in the pathogenesis of hepatic IR, providing a new perspective for further exploring the role of ion in the onset and development of IR.
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4.
Developing a Mathematical Model of Intracellular Calcium Dynamics for Evaluating Combined Anticancer Effects of Afatinib and RP4010 in Esophageal Cancer.
Chang, Y, Funk, M, Roy, S, Stephenson, E, Choi, S, Kojouharov, HV, Chen, B, Pan, Z
International journal of molecular sciences. 2022;(3)
Abstract
Targeting dysregulated Ca2+ signaling in cancer cells is an emerging chemotherapy approach. We previously reported that store-operated Ca2+ entry (SOCE) blockers, such as RP4010, are promising antitumor drugs for esophageal cancer. As a tyrosine kinase inhibitor (TKI), afatinib received FDA approval to be used in targeted therapy for patients with EGFR mutation-positive cancers. While preclinical studies and clinical trials have shown that afatinib has benefits for esophageal cancer patients, it is not known whether a combination of afatinib and RP4010 could achieve better anticancer effects. Since TKI can alter intracellular Ca2+ dynamics through EGFR/phospholipase C-γ pathway, in this study, we evaluated the inhibitory effect of afatinib and RP4010 on intracellular Ca2+ oscillations in KYSE-150, a human esophageal squamous cell carcinoma cell line, using both experimental and mathematical simulations. Our mathematical simulation of Ca2+ oscillations could fit well with experimental data responding to afatinib or RP4010, both separately or in combination. Guided by simulation, we were able to identify a proper ratio of afatinib and RP4010 for combined treatment, and such a combination presented synergistic anticancer-effect evidence by experimental measurement of intracellular Ca2+ and cell proliferation. This intracellular Ca2+ dynamic-based mathematical simulation approach could be useful for a rapid and cost-effective evaluation of combined targeting therapy drugs.
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5.
The roles of transmembrane family proteins in the regulation of store-operated Ca2+ entry.
Zhang, N, Pan, H, Liang, X, Xie, J, Han, W
Cellular and molecular life sciences : CMLS. 2022;(2):118
Abstract
Store-operated Ca2+ entry (SOCE) is a major pathway for calcium signaling, which regulates almost every biological process, involving cell proliferation, differentiation, movement and death. Stromal interaction molecule (STIM) and ORAI calcium release-activated calcium modulator (ORAI) are the two major proteins involved in SOCE. With the deepening of studies, more and more proteins are found to be able to regulate SOCE, among which the transmembrane (TMEM) family proteins are worth paying more attention. In addition, the ORAI proteins belong to the TMEM family themselves. As the name suggests, TMEM family is a type of proteins that spans biological membranes including plasma membrane and membrane of organelles. TMEM proteins are in a large family with more than 300 proteins that have been already identified, while the functional knowledge about the proteins is preliminary. In this review, we mainly summarized the TMEM proteins that are involved in SOCE, to better describe a picture of the interaction between STIM and ORAI proteins during SOCE and its downstream signaling pathways, as well as to provide an idea for the study of the TMEM family proteins.
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6.
Activation of endo-lysosomal two-pore channels by NAADP and PI(3,5)P2. Five things to know.
Patel, S, Yuan, Y, Gunaratne, GS, Rahman, T, Marchant, JS
Cell calcium. 2022;:102543
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Abstract
Two-pore channels are ancient members of the voltage-gated ion channel superfamily that are expressed predominantly on acidic organelles such as endosomes and lysosomes. Here we review recent advances in understanding how TPCs are activated by their ligands and identify five salient features: (1) TPCs are Ca2+-permeable non-selective cation channels gated by NAADP. (2) NAADP activation is indirect through associated NAADP receptors. (3) TPCs are also Na+-selective channels gated by PI(3,5)P2. (4) PI(3,5)P2 activation is direct through a structurally-resolved binding site. (5) TPCs switch their ion selectivity in an agonist-dependent manner.
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OXER1 mediates testosterone-induced calcium responses in prostate cancer cells.
Panagiotopoulos, AA, Kalyvianaki, K, Serifoglou, B, Konstantinou, E, Notas, G, Castanas, E, Kampa, M
Molecular and cellular endocrinology. 2022;:111487
Abstract
In prostate cancer, calcium homeostasis plays a significant role in the disease's development and progression. Intracellular calcium changes are an important secondary signal, triggered by a variety of extracellular stimuli, that controls many cellular functions. One of the main events affecting calcium is androgen signaling. Indeed, via calcium changes, androgens regulate cell processes like cell growth, differentiation and motility. In the present work we explored the nature of the receptor involved in calcium response induced by membrane-acting testosterone in prostate cancer cells. We report that testosterone, independently of the presence of the classical androgen receptor, can rapidly increase intracellular calcium from calcium stores, through the oxoeicosanoid receptor 1 (OXER1) and a specific signaling cascade that triggers calcium release from the endoplasmic reticulum. These findings reveal for the first time the receptor involved in the rapid calcium changes induced by androgens. Moreover, they further support the notion that androgens, even in the absence of AR, can still exert specific effects that regulate cancer cell fate.
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Association between blood lead levels and markers of calcium homeostasis: a systematic review and meta-analysis.
Upadhyay, K, Viramgami, A, Bagepally, BS, Balachandar, R
Scientific reports. 2022;(1):1850
Abstract
Chronic Pb exposure associated systemic illness are partly posited to involve calcium homeostasis. Present systematic review aims to comprehensively evaluate the association between chronic lead exposure and markers of calcium homeostasis. Observational studies documenting the changes in calcium homeostasis markers (i.e. serum calcium, parathyroid hormone, vitamin D & calcitonin) between occupationally Pb exposed group and control group were systematically searched from pubmed-Medline, Scopus, and Embase digital databases since inception to September 24, 2021. The protocol was earlier registered at PROSPERO (ID: CRD42020199503) and executed adhering to PRISMA 2020 guidelines. Mean differences of calcium homeostasis markers between the groups were analysed using random-effects model. Conventional I2 statistics was employed to assess heterogeneity, while the risk for various biases were assessed using Newcastle Ottawa Scale. Sub-group, sensitivity and meta-regression analyses were performed where data permitted. Eleven studies including 837 Pb exposed and 739 controls were part of the present study. Pb exposed group exhibited higher mean blood lead level [i.e. 36.13 (with 95% CI 25.88-46.38) µg/dl] significantly lower serum calcium (i.e. - 0.72 mg/dl with 95% CI - 0.36 to - 1.07) and trend of higher parathyroid levels and lower vitamin D levels than controls. Heterogeneity was high (I2 > 90%) among the studies. Considering the cardinal role of calcium in multiple biological functions, present observations emphasis the need for periodic evaluation of calcium levels and its markers among those with known cumulative Pb exposure.
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A Review of Current Clinical Concepts in the Pathophysiology, Etiology, Diagnosis, and Management of Hypercalcemia.
Tonon, CR, Silva, TAAL, Pereira, FWL, Queiroz, DAR, Junior, ELF, Martins, D, Azevedo, PS, Okoshi, MP, Zornoff, LAM, de Paiva, SAR, et al
Medical science monitor : international medical journal of experimental and clinical research. 2022;:e935821
Abstract
Calcium is the most abundant extracellular cation in the body, and it is responsible for structural and enzymatic functions. Calcium homeostasis is regulated by 3 factors: calcitonin, vitamin D, and parathyroid hormone (PTH). Hypercalcemia is defined by a serum calcium concentration >10.5 mg/dL, and it is classified into mild, moderate, and severe, depending on calcium values. Most cases are caused by primary hyperparathyroidism and malignancies. Various mechanisms are involved in the pathophysiology of hypercalcemia, such as excessive PTH production, production of parathyroid hormone-related protein (PTHrp), bone metastasis, extrarenal activation of vitamin D, and ectopic PTH secretion. The initial approach is similar in most cases, but a definitive treatment depends on etiology, that is why etiological investigation is mandatory in all cases. The majority of patients are asymptomatic and diagnosed during routine exams; only a small percentage of patients present with severe manifestations which can affect neurological, muscular, gastrointestinal, renal, and cardiovascular systems. Clinical manifestations are related to calcium levels, with higher values leading to more pronounced symptoms. Critically ill patients should receive treatment as soon as diagnosis is made. Initial treatment involves vigorous intravenous hydration and drugs to reduce bone resorption such as bisphosphonates and, more recently, denosumab, in refractory cases; also, corticosteroids and calcitonin can be used in specific cases. This review aims to provide a clinical update on current concepts of the pathophysiology of calcium homeostasis, epidemiology, screening, clinical presentation, diagnosis, and management of hypercalcemia.
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Identification of the Large-Conductance Ca2+-Regulated Potassium Channel in Mitochondria of Human Bronchial Epithelial Cells.
Sek, A, Kampa, RP, Kulawiak, B, Szewczyk, A, Bednarczyk, P
Molecules (Basel, Switzerland). 2021;(11)
Abstract
Mitochondria play a key role in energy metabolism within the cell. Potassium channels such as ATP-sensitive, voltage-gated or large-conductance Ca2+-regulated channels have been described in the inner mitochondrial membrane. Several hypotheses have been proposed to describe the important roles of mitochondrial potassium channels in cell survival and death pathways. In the current study, we identified two populations of mitochondrial large-conductance Ca2+-regulated potassium (mitoBKCa) channels in human bronchial epithelial (HBE) cells. The biophysical properties of the channels were characterized using the patch-clamp technique. We observed the activity of the channel with a mean conductance close to 285 pS in symmetric 150/150 mM KCl solution. Channel activity was increased upon application of the potassium channel opener NS11021 in the micromolar concentration range. The channel activity was completely inhibited by 1 µM paxilline and 300 nM iberiotoxin, selective inhibitors of the BKCa channels. Based on calcium and iberiotoxin modulation, we suggest that the C-terminus of the protein is localized to the mitochondrial matrix. Additionally, using RT-PCR, we confirmed the presence of α pore-forming (Slo1) and auxiliary β3-β4 subunits of BKCa channel in HBE cells. Western blot analysis of cellular fractions confirmed the mitochondrial localization of α pore-forming and predominately β3 subunits. Additionally, the regulation of oxygen consumption and membrane potential of human bronchial epithelial mitochondria in the presence of the potassium channel opener NS11021 and inhibitor paxilline were also studied. In summary, for the first time, the electrophysiological and functional properties of the mitoBKCa channel in a bronchial epithelial cell line were described.