Overexpression of S100A1 in Osteosarcoma Inhibits Tumor Proliferation and Progression.

Background: Osteosarcoma is the most common primary malignant tumor of bone. Abnormal expression of S100A1 protein is closely related to the occurrence and development of malignant tumors. However, S100A1 in osteosarcoma has not been studied. Methods: All osteosarcoma tissues were collected from patients who received surgical therapy at the Affiliated Hospital of Inner Mongolia Medical University, China in 2020. QRT-PCR and western blot assays were used to detect the expression of S100A1 in osteosarcoma tissues and cells. The negative effect of S100A1 on osteosarcoma cell growth was confirmed by vitro and vivo experiments. Results: S100A1 inhibited the growth of osteosarcoma cells in vitro. Overexpression of S100A1 may inhibit the proliferation of osteosarcoma cells by preventing the activation of AKT signaling pathway by western blot assay. Finally, animal experiments confirmed that overexpression of S100A1 could inhibit the proliferation of osteosarcoma cells. Overexpression of S100A1 obtained better survival benefit in mice. Conclusion: Our findings provided a new insight to the treatment of osteosarcoma. It also raised the possibility that S100A1 could be used in targeted therapies for osteosarcoma.

Changes and clinical significance of plasma S100A1 protein, nuclear factor-κB p65 and interleukin-6 levels in patients with acute ischemic cerebrovascular diseases / 中国基层医药

Objective:To investigate the changes and clinical significance of plasma S100A1 protein, nuclear factor-κB p65 (NF-κB p65) and interleukin-6 (IL-6) levels in patients with acute ischemic cerebrovascular diseases.Methods:A total of 141 patients with acute ischemic cerebral infarction (AICI; AICI group) and 20 patients with transient ischemic attack (TIA; TIA group) who received treatment in Northern Jiangsu People's Hospital from April to November 2020 were included in this study. According to the volume of cerebral infarct, the AICI group was subdivided into small-volume cerebral infarct (SCI group, n = 78), moderate-volume cerebral infarct (MCI group, n = 32) and large-volume cerebral infract (LCI group, n = 31) groups. An additional 31 healthy controls who concurrently received physical examination were included as controls (HC group). S100A1, NF-κB p65, and IL-6 levels were compared between AICI, TIA and HC groups and between SCI, MCI and LCI groups. S100A1, NF-κB p65, and IL-6 levels were correlated with the National Institutes of Health Stroke Scale score and the volume of cerebral infarct. The receiver operating characteristic curve (ROC) was drawn to analyze the diagnostic value of S100A1, NF-κB p65, and IL-6 levels for AICI. Results:S100A1, NF-κB p65, and IL-6 levels in the AICI group were (230.96 ± 39.37) ng/L, (3.99 ± 0.65) mg/L, (13.32 ± 1.57) ng/L, respectively, which were significantly higher than (185.85 ± 43.24) ng/L, (3.58 ± 0.74) mg/L, (11.61 ± 1.67) ng/L in the TIA group ( t = 4.95, 2.39, 4.14, all P < 0.05) and (181.47 ± 27.39) ng/L, (3.51 ± 0.99) mg/L, (11.42 ± 2.34) ng/L in the HC group ( t = 6.54, 3.32, 5.55, all P < 0.05). There were no significant differences in S100A1, NF-κB p65, and IL-6 levels between TIA and HC groups (all P > 0.05). S100A1, NF-κB p65, and IL-6 levels in the LCI group were (254.25 ± 37.07) ng/L, (4.41 ± 0.45) mg/L, and (14.00 ± 1.40) ng/L, respectively, which were significantly higher than (225.42 ± 30.92) ng/L, (3.85 ± 0.64) mg/L, (12.77 ± 1.31) ng/L in the MCI group ( t = 3.04, 3.60, 3.20, all P < 0.05) and (223.98 ± 40.21) ng/L, (3.88 ± 0.66) mg/L, (13.27 ± 1.65) ng/L in the SCI group ( t = 3.79, 4.01, 2.25, all P < 0.05). There were no significant differences in S100A1, NF-κB p65, and IL-6 levels between MCI and SCI groups (all P > 0.05). S100A1 and NF-κB p65 levels in patients with AICI were positively correlated with the volume of cerebral infarct ( r = 0.24, 0.27, both P < 0.05). S100A1 and IL-6 levels in patients with AICI were positively correlated with the National Institutes of Health Stroke Scale score ( r = 0.24, 0.28, both P < 0.05). The areas under the curves plotting S100A1, NF-κB p65, and IL-6 levels against AICI diagnosis were 0.818, 0.667 and 0.754, respectively. The optimal cutoff values were 181.03, 3.50 and 10.79, respectively. The corresponding sensitivities were 95.0%, 76.6% and 97.2%, respectively, and the specificities were 37.3%, 45.1% and 49.0%, respectively. Conclusion:Increased S100A1, NF-κB p65, and IL-6 levels in patients with AICI are closely related to the severity of AICI.

Molecular Basis of S100A1 Activation and Target Regulation Within Physiological Cytosolic Ca2+ Levels.

The S100A1 protein regulates cardiomyocyte function through its binding of calcium (Ca2+) and target proteins, including titin, SERCA, and RyR. S100A1 presents two Ca2+ binding domains, a high-affinity canonical EF-hand (cEF) and a low-affinity pseudo EF-hand (pEF), that control S100A1 activation. For wild-type S100A1, both EF hands must be bound by Ca2+ to form the open state necessary for target peptide binding, which requires unphysiological high sub-millimolar Ca2+ levels. However, there is evidence that post-translational modifications at Cys85 may facilitate the formation of the open state at sub-saturating Ca2+ concentrations. Hence, post-translational modifications of S100A1 could potentially increase the Ca2+-sensitivity of binding protein targets, and thereby modulate corresponding signaling pathways. In this study, we examine the mechanism of S100A1 open-closed gating via molecular dynamics simulations to determine the extent to which Cys85 functionalization, namely via redox reactions, controls the relative population of open states at sub-saturating Ca2+ and capacity to bind peptides. We further characterize the protein's ability to bind a representative peptide target, TRKT12 and relate this propensity to published competition assay data. Our simulation results indicate that functionalization of Cys85 may stabilize the S100A1 open state at physiological, micromolar Ca2+ levels. Our conclusions support growing evidence that S100A1 serves as a signaling hub linking Ca2+ and redox signaling pathways.

LC/MS/MS-based quantitation of pig and human S100A1 protein in cardiac tissues: Application to gene therapy.

The S100A1 protein is a target of interest for the treatment of heart failure as it has been previously reported to be depleted in failing cardiomyocytes. A gene therapy approach leading to increased expression levels of the protein directly in the heart could potentially lead to restoration of contractile function and improve overall cell survival. S100A1 is a relatively small soluble protein that is extremely well conserved across species with only a single amino acid difference between the sequences in human and pig, a commonly used pre-clinical model for evaluation of efficacy, biodistribution and safety for cardiac-directed gene therapy approaches. This high homology presents a bioanalytical challenge for the accurate detection and quantitation of both endogenous (pig) and exogenous (human) transduced S100A1 proteins post treatment using a human S100A1 gene therapy in pigs. Here we present a sensitive and selective LC-MS/MS approach that can easily differentiate and simultaneously quantitate both human and pig S100A1 proteins. Additionally, we report on a detailed profiling of S100A1 protein in various pig tissues, a comprehensive evaluation of S100A1 distribution in pig hearts and a comparison to S100A1 levels in human cardiac samples.

S100A1 protein and heart failure / 第二军医大学学报

S100A,a Ca2+-depending inotropic factor in the heart,is found decreased during hear failure. Increase of S100A1 protein expression can improve cardiac function by regulating Ca2+ transportation, inhibiting left ventricular remodeling, decreasing apoptosis,and restoring energy supply of failing heart. Therefore,recovery of S100A1 protein expression in the failing heart is an effective strategy for treatment of heart failure.