Secondary Modification of S100B Influences Anti Amyloid-ß Aggregation Activity and Alzheimer's Disease Pathology.

Proteinaceous aggregates accumulate in neurodegenerative diseases such as Alzheimer's Disease (AD), inducing cellular defense mechanisms and altering the redox status. S100 pro-inflammatory cytokines, particularly S100B, are activated during AD, but recent findings reveal an unconventional molecular chaperone role for S100B in hindering Aß aggregation and toxicity. This suggests a potential protective role for S100B at the onset of Aß proteotoxicity, occurring in a complex biochemical environment prone to oxidative damage. Herein, we report an investigation in which extracellular oxidative conditions are mimicked to test if the susceptibility of S100B to oxidation influences its protective activities. Resorting to mild oxidation of S100B, we observed methionine oxidation as inferred from mass spectrometry, but no cysteine-mediated crosslinking. Structural analysis showed that the folding, structure, and stability of oxidized S100B were not affected, and nor was its quaternary structure. However, studies on Aß aggregation kinetics indicated that oxidized S100B was more effective in preventing aggregation, potentially linked to the oxidation of Met residues within the S100:Aß binding cleft that favors interactions. Using a cell culture model to analyze the S100B functions in a highly oxidative milieu, as in AD, we observed that Aß toxicity is rescued by the co-administration of oxidized S100B to a greater extent than by S100B. Additionally, results suggest a disrupted positive feedback loop involving S100B which is caused by its oxidation, leading to the downstream regulation of IL-17 and IFN-α2 expression as mediated by S100B.

Tumor microenvironment-derived S100A8/A9 is a novel prognostic biomarker for advanced melanoma patients and during immunotherapy with anti-PD-1 antibodies.

BACKGROUND: Predicting metastasis in melanoma patients is important for disease management and could help to identify those who might benefit from adjuvant treatment. The aim of this study was to investigate whether the tumor microenvironment-derived protein S100A8/A9 qualifies as prognostic marker for melanoma patients, also in the setting of immunotherapy. METHODS: S100A8/A9 gene and protein expression were analyzed on melanocytic nevi, primary melanomas and metastases using a cDNA library and three independent tissue-microarrays (TMA). Serum levels of S100A8/A9 were measured using a specific ELISA in two independent cohorts of 354 stage III and stage IV melanoma patients as well as in two independent cohorts of patients treated with the PD-1 antibody pembrolizumab. RESULTS: cDNA analysis revealed an upregulation of S100A8 and S100A9 gene expression in melanoma metastases compared to primary melanomas. Significantly higher numbers of infiltrating S100A8/A9 positive cells were found in tissue samples of metastasizing primary melanomas compared to non-metastasizing melanomas (P < .0001) and in melanomas of short-term survivors compared to long-term survivors (P < .0001). Serum S100A8/A9 levels > 5.5 mg/l were associated with impaired overall survival in two independent cohorts (both P < .0001). Importantly, patients with serum elevated S100A8/A9 treated with pembrolizumab showed significantly impaired survival compared to patients with lower S100A8/A9 levels (cohort 1: P = .0051; cohort 2: P < .0001). CONCLUSIONS: The tumor microenvironment-associated protein S100A8/A9 serves as a novel prognostic marker for metastasis and survival of metastatic melanoma patients and predicts response to immunotherapy with pembrolizumab. These data underscore the significance of tumor microenvironment-derived factors as suitable biomarkers for melanoma.

The expressions of calcium binding protein and its clinical significances in hepatocelluar carcinoma tissue and blood plasma / 中华消化杂志

Objective To explore the expression of calcium binding protein (S100A11) and its clinical significances in human hepatocellular carcinoma (HCC) tissue and blood plasma. Methods The expressions of S100A11 in 46 cases of HCC tissues and their paracancerous tissues were detected by immunohistochemistry. The relationship between S100A11 expression level in HCC tissues and clinical parameters was analyzed. The S100A11 expression levels in blood plasma of HCC patients (62 cases), liver cirrhosis patients (32 cases), chronic hepatitis patients (30 cases) and healthy subjects (30 cases) were detected. The sensitivity and specificity of S100A11, alpha fetoprotein (AFP) and γ-glutamyl transpeptidase Ⅱ (GGT-Ⅱ ) in HCC diagnosis were compared. Results The positive rate of S100A11 in HCC tissue (78. 3%) was significantly higher than that in paracancerous tissues (19. 6%) (P<0. 05). The expression level was correlated with the degree of differentiation, the lower differentiation degree with the higher expression level. According to ROC curve, if the cutoff points for diagnosis was set at 7. 3 μg/L, the positive rate of S100A11 in HCC patients blood plasma was 30. 6% , which was significantly higher than that in the blood plasma of patients with liver cirrhosis, patients with chronic hepatitis and healthy persons (P<0. 05). There was no correlation between S100A11 and AFP or GGT-Ⅱ in the blood plasma of HCC patients. These three indicators were complementary in HCC diagnosis, and the diagnostic sensitivity increased to 84.5% with combined detection. Conclusions S100All may be related to HCC genesis and development. The HCC diagnostic sensitivity may be increased with combined detection of S100All ,AFP and GOT- Ⅱ.