HDAC7/c-Myc signaling pathway promotes the proliferation and metastasis of choroidal melanoma cells.

Choroidal melanoma (CM) is the most common type of diagnosed uveal melanoma (UM), which is prone to metastasis and exhibits a poor prognosis. The molecular mechanisms underlying CM progression need further elucidation to research effective therapeutic strategies. Histone deacetylase 7 (HDAC7) is very important in regulating cancer progression, but the significance and effect of HDAC7 on CM progression are unclear. In the present study, we found that HDAC7 is overexpressed in CM tissues versus normal tissues. We built HDAC7 overexpressing CM cell lines to study the functions of HDAC7 in CM progression and verified that upregulation of HDAC7 promoted the proliferation and metastasis of CM cells, while pharmacological inhibition of HDAC7 suppressed both the proliferation and metastasis of CM cells. Furthermore, we found that the aforementioned cancer-promoting effect of HDAC7 was mediated by c-Myc. Targeted inhibition of c-Myc inhibited CM progression by interfering with the HDAC7/c-Myc signaling pathway. Our study highlighted the function of targeting the HDAC7/c-Myc signaling pathway to intervene in the pathological process of CM, which provides potential therapeutic strategies for CM treatment.

CaMKII orchestrates endoplasmic reticulum stress and apoptosis in doxorubicin-induced cardiotoxicity by regulating the IRE1α/XBP1s pathway.

Doxorubicin (Dox), an anthracycline antibiotic with potent antitumor effects, has limited clinical applications due to cumulative cardiotoxicity. Ca2+ /calmodulin-dependent protein kinase II (CaMKII) is implicated in the pathological progression of Dox-induced cardiotoxicity. This study examined the hypothesis that CaMKII exacerbates Dox-induced cardiotoxicity by promoting endoplasmic reticulum stress and apoptosis through regulation of the inositol-requiring enzyme 1α (IRE1α)/spliced X-box binding protein 1 (XBP1s) pathway. Our results demonstrated that CaMKII activation and IRE1α/XBP1s pathway were involved in Dox-treated hearts. CaMKII inhibition with KN-93 ameliorated Dox-induced cardiac dysfunction and pathological myocardial changes. In addition, CaMKII inhibition prevented Dox-induced endoplasmic reticulum stress and apoptosis. Moreover, CaMKII inhibition increased the expression of IRE1α and XBP1s in Dox-treated hearts. The IRE1α inhibitor 4µ8C blocked the protective effect of CaMKII inhibition against Dox-induced cardiotoxicity. Mechanistically, 4µ8C prevented the effects of CaMKII inhibition on Dox-induced endoplasmic reticulum stress and apoptosis by inhibiting the expression of IRE1α and XBP1s. Additionally, treatment with rhADAMTS13 decreased the protein level of thrombospondin 1 (TSP1) and the phosphorylation of CaMKII in Dox-treated human AC16 cardiomyocytes. Taken together, these results demonstrate that the ADAMTS13-TSP1 axis regulates CaMKII activation and exacerbates Dox-induced cardiotoxicity by triggering endoplasmic reticulum stress and apoptosis by inhibiting the IRE1α/XBP1s pathway.

Mitosis-related gene CENP-U as a potential biomarker in malignancy.

BACKGROUND: Centromere protein U (CENP-U) is a component of the kinetochore and can regulate the cell cycle as a receptor of polo-like kinase 1 (PLK1). Recent studies have partially identified the role of CENP-U in tumor progression, but the underlying mechanisms of CENP-U in tumor immunity remain obscure. METHODS: We performed pan-cancer analysis to evaluate the role of CENP-U in immunity and proliferation with data from The Cancer Genome Atlas (TCGA), Cancer Cell Line Encyclopedia (CCLE) datasets, and Genotype-Tissue Expression (GTEx) project. Results of CENP-U expression and related clinicopathological data were obtained to show the expression levels, prognosis, tumor progression, immune neoantigens, and immune checkpoints of CENP-U in 33 tumors. The Tumor Immune Estimation Resource (TIMER) dataset was used to analyze immune infiltration scores. RESULTS: Results of the pan-cancer analysis demonstrated that CENP-U is differentially expressed in normal tissues and common tumor tissues. Moreover, differentially expressed CENP-U was also identified between matched normal and tumor tissues, and the high expression level of CENP-U was associated with poor prognosis for 33 kinds of tumor except for that of thymoma (THYM) and lymphoid neoplasm diffuse large B-cell lymphoma (DLBC). Furthermore, the correlation between CENP-U expression and immune checkpoints and immune neoantigens was determined. In addition, CENP-U expression was correlated with tumor-infiltrating immune cells especially in THYM but not in lung squamous cell carcinoma (LUSC), esophageal carcinoma (ESCA), or lung adenocarcinoma (LUAD). Finally, gene set enrichment analysis (GSEA) indicated that CENP-U is critically involved in tumor proliferation, immunity, and metabolism. CONCLUSIONS: CENP-U, a mitosis-related kinase, was found to be differentially expressed across different cancer types and to play an important role in tumor progression and immunity. CENP-U holds the potential to be a prognostic marker, whose targeting may provide therapeutic benefit.