Dysregulated expression of cholesterol biosynthetic genes in Alzheimer's disease alters epigenomic signatures of hippocampal neurons.

Aging is the main risk factor of cognitive neurodegenerative diseases such as Alzheimer's disease, with epigenome alterations as a contributing factor. Here, we compared transcriptomic/epigenomic changes in the hippocampus, modified by aging and by tauopathy, an AD-related feature. We show that the cholesterol biosynthesis pathway is severely impaired in hippocampal neurons of tauopathic but not of aged mice pointing to vulnerability of these neurons in the disease. At the epigenomic level, histone hyperacetylation was observed at neuronal enhancers associated with glutamatergic regulations only in the tauopathy. Lastly, a treatment of tau mice with the CSP-TTK21 epi-drug that restored expression of key cholesterol biosynthesis genes counteracted hyperacetylation at neuronal enhancers and restored object memory. As acetyl-CoA is the primary substrate of both pathways, these data suggest that the rate of the cholesterol biosynthesis in hippocampal neurons may trigger epigenetic-driven changes, that may compromise the functions of hippocampal neurons in pathological conditions.

TTK inhibition activates STING signal and promotes anti-PD1 immunotherapy in breast cancer.

Despite progress in the application of checkpoint immunotherapy against various tumors, attempts to utilize immune checkpoint blockade (ICB) agents in triple negative breast cancer (TNBC) have yielded limited clinical benefits. The low overall response rate of checkpoint immunotherapy in TNBC may be attributed to the immunosuppressive tumor microenvironment (TME). In this study, we investigated the role of mitogen-associated kinase TTK in reprogramming immune microenvironment in TNBC. Notably, TTK inhibition by BAY-1217389 induced DNA damage and the formation of micronuclei containing dsDNA in the cytosol, resulting in elicition of STING signal pathway and promoted antitumor immunity via the infiltration and activation of CD8+ T cells. Moreover, TTK inhibition also upregulated the expression of PD-L1, demonstrating a synergistic effect with anti-PD1 therapy in 4T1 tumor-bearing mice. Taken together, TTK inhibition facilitated anti-tumor immunity mediated by T cells and enhanced sensitivity to PD-1 blockade, providing a rationale for the combining TTK inhibitors with immune checkpoint blockade in clinical trials.

Upregulation of TTK expression is associated with poor prognosis and immune infiltration in endometrial cancer patients.

BACKGROUND: Threonine and tyrosine kinase (TTK) is associated with invasion and metastasis in various tumors. However, the prognostic importance of TTK and its correlation with immune infiltration in endometrial cancer (EC) remain unclear. METHODS: The expression profile of TTK was analyzed using data from The Cancer Genome Atlas (TCGA) and the Clinical Proteome Cancer Analysis Consortium (CPTAC). TTK protein and mRNA levels were verified in EC cell lines. Receiver operating characteristic (ROC) curve analysis was used to evaluate the ability of TTK to distinguish between normal and EC tissues. K-M survival analysis was also conducted to evaluate the impact of TTK on survival outcomes. Protein‒protein interaction (PPI) networks associated with TTK were explored using the STRING database. Functional enrichment analysis was performed to elucidate the biological functions of TTK. TTK mRNA expression and immune infiltration correlations were examined using the Tumor Immune Estimation Resource (TIMER) and the Tumor-Immune System Interaction Database (TISIDB). RESULTS: TTK expression was significantly greater in EC tissues than in adjacent normal tissues. Higher TTK mRNA expression was associated with tumor metastasis and advanced TNM stage. The protein and mRNA expression of TTK was significantly greater in tumor cell lines than in normal endometrial cell lines. ROC curve analysis revealed high accuracy (94.862%), sensitivity (95.652%), and specificity (94.894%) of TTK in differentiating EC from normal tissues. K-M survival analysis demonstrated that patients with high TTK expression had worse overall survival (OS) and disease-free survival (DFS) rates. Correlation analysis revealed that TTK mRNA expression was correlated with B cells and neutrophils. CONCLUSION: TTK upregulation is significantly associated with poor survival outcomes and immune infiltration in patients with EC. TTK can serve as a potential biomarker for poor prognosis and a promising immunotherapy target in EC. Further investigation of the role of TTK in EC may provide valuable insights for therapeutic interventions and personalized treatment strategies.

Discovery of a potent and selective covalent threonine tyrosine kinase (TTK) inhibitor.

Threonine tyrosine kinase (TTK) is a critical component of the spindle assembly checkpoint and plays a pivotal role in mitosis. TTK has been identified as a potential therapeutic target for human cancers. Here, we describe our design, synthesis and evaluation of a class of covalent TTK inhibitors, exemplified by 16 (SYL1073). Compound 16 potently inhibits TTK kinase with an IC50 of 0.016 µM and displays improved selectivity in a panel of kinases. Mass spectrometry analysis reveals that 16 covalently binds to the C604 cysteine residue in the hinge region of the TTK kinase domain. Furthermore, 16 achieves strong potency in inhibiting the growth of various human cancer cell lines, outperforming its relative reversible inhibitor, and eliciting robust downstream effects. Taken together, compound 16 provides a valuable lead compound for further optimization toward the development of drug for treatment of human cancers.

In Vivo Bioluminescence Imaging Reveals Differences in Leishmania infantum Parasite Killing Kinetics by Antileishmanial Reference Drugs.

The bioluminescent Leishmania infantum BALB/c mouse model was used to evaluate the parasiticidal drug action kinetics of the reference drugs miltefosine, paromomycin, sodium stibogluconate, and liposomal amphotericin B. Infected mice were treated for 5 days starting from 7 days post-infection, and parasite burdens were monitored over time via bioluminescence imaging (BLI). Using nonlinear regression analyses of the BLI signal, the parasite elimination half-life (t1/2) in the liver, bone marrow, and whole body was determined and compared for the different treatment regimens. Significant differences in parasiticidal kinetics were recorded. A single intravenous dose of 0.5 mg/kg liposomal amphotericin B was the fastest acting with a t1/2 of less than 1 day. Intraperitoneal injection of paromomycin at 320 mg/kg for 5 days proved to be the slowest with a t1/2 of about 5 days in the liver and 16 days in the bone marrow. To conclude, evaluation of the cidal kinetics of the different antileishmanial reference drugs revealed striking differences in their parasite elimination half-lives. This BLI approach also enables an in-depth pharmacodynamic comparison between novel drug leads and may constitute an essential tool for the design of potential drug combinations.

Comprehensive Bioinformatics Analysis and Machine Learning of TTK as a Transhepatic Arterial Chemoembolization Resistance Target in Hepatocellular Carcinoma.

Transhepatic arterial chemoembolization (TACE) is the standard treatment for intermediate-stage hepatocellular carcinoma (HCC). However, a significant proportion of patients are non-responders or poor responders to TACE. Therefore, our aim is to identify the targets of TACE responders or non-responders. GSE104580 was utilized to identify differentially expressed genes (DEGs) in TACE responders and non-responders. Following the protein-protein interaction (PPI) analysis, hub genes were identified using the MCC and MCODE plugins in Cytoscape software, as well as LASSO regression analysis. Gene set enrichment analysis (GSEA) was performed to investigate potential mechanisms. Subsequently, the hub genes were validated using data from The Cancer Genome Atlas (TCGA), the Cancer Cell Line Encyclopedia (CCLE), and The Human Protein Atlas (HPA) database. To evaluate the clinical significance of the hub genes, Kaplan-Meier (KM) survival and Cox regression analysis were employed. A total of 375 DEGs were identified, with 126 remaining following PPI analysis, and TTK, a dual-specificity protein kinase associated with cell proliferation, was ultimately identified as the hub gene through multiple screening methods. Data analysis from TCGA, CCLE, and HPA databases revealed elevated TTK expression in HCC tissues. GSEA indicated that the cell cycle, farnesoid X receptor pathway, PPAR pathway, FOXM1 pathway, E2F pathway, and ferroptosis could be potential mechanisms for TACE non-responders. Analysis of immune cell infiltration showed a significant correlation between TTK and Th2 cells. KM and Cox analysis suggested that HCC patients with high TTK expression had a worse prognosis. TTK may play a pivotal role in HCC patients' response to TACE therapy and could be linked to the prognosis of these patients.

Energy­stress­mediated activation of AMPK sensitizes MPS1 kinase inhibition in triple­negative breast cancer.

Monopolar spindle 1 kinase (Mps1, also known as TTK protein kinase) inhibitors exert marked anticancer effects against triple­negative breast cancer (TNBC) by causing genomic instability and cell death. As aneuploid cells are vulnerable to compounds that induce energy stress through adenosine monophosphate­activated protein kinase (AMPK) activation, the synergistic effect of Mps1/TTK inhibition and AMPK activation was investigated in the present study. The combined effects of CFI­402257, an Mps1/TTK inhibitor, and AICAR, an AMPK agonist, were evaluated in terms of cytotoxicity, cell­cycle distribution, and in vivo xenograft models. Additional molecular mechanistic studies were conducted to elucidate the mechanisms underlying apoptosis and autophagic cell death. The combination of CFI­402257 and AICAR showed selective cytotoxicity in a TNBC cell line. The formation of polyploid cells was attenuated, and apoptosis was increased by the combination treatment, which also induced autophagy through dual inhibition of the PI3K/Akt/mTOR and mitogen­activated protein kinase (MAPK) signaling pathways. Additionally, the combination therapy showed strongly improved efficacy in comparison with CFI­402257 and AICAR monotherapy in the MDA­MB­231 xenograft model. The present study suggested that the combination of CFI­402257 and AICAR is a promising therapeutic strategy for TNBC.

LINC01572 promotes the malignant progression of lung adenocarcinoma by modulating p53 mediated by miRNA-338-5p/TTK axis.

OBJECTIVES: Lung cancer is one of the malignant tumors that threaten human health seriously. Long non-coding RNA (lncRNA) is an important factor affecting tumorigenesis and development. However, the mechanism of lncRNA in lung cancer progression remains to be further explored. METHODS: In this study, the TCGA database was analyzed, and LINC01572 was found to be increased in lung adenocarcinoma (LUAD) tissues. Thereafter, with the help of databases including lncBase, TargetScan, and mirDIP, as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, LINC01572/miRNA-338-5p/TTK regulatory axis and downstream p53 signaling pathway were excavated. qRT-PCR was adopted to detect levels of LINC01572, miRNA-338-5p, and TTK in LUAD cells. The role that LINC01572 played in LUAD cells was validated by CCK-8 assay, flow cytometry, colony formation, Transwell, and scratch healing assays. The binding ability between LINC01572/TTK and miRNA-338-5p was then verified by dual-luciferase and RIP analysis. KEY FINDINGS: The results of this study demonstrated that LINC01572 was elevated in LUAD cells compared with normal cells. The overexpression of LINC01572 promoted the proliferative and migratory properties of LUAD cells but inhibited cell apoptosis. The inhibition of LINC01572 resulted in the opposite result. In addition, rescue experiments revealed that LINC01572, as a molecular sponge of miRNA-338-5p, targeted TTK to manipulate p53 for facilitating LUAD cell malignant progression. Apart from this, we constructed a mouse xenograft model and confirmed that the knockdown of LINC01572 hindered the growth of LUAD solid tumors in vivo. CONCLUSIONS: Our findings illuminated the molecular mechanism of LINC01572 influencing LUAD and provided new insights for targeted therapy of LUAD cells.

Structural valve failure of TTK Chitra heart valve prosthesis.

Mechanical prosthetic valve dysfunction can be structural or non-structural. Structural valve dysfunction includes disc dislodgement, disc fracture, and strut fracture. These events in an implanted valve are rare but could pose a risk to life. TTK Chitra heart valve prosthesis (CHVP), an Indian-made single tilting disc valve, has been implanted since 1990 as reported by Vayalappil and Bhuvaneswar (2005). There is limited literature on the structural valve dysfunction of CHVP. We hereby submit images of the dysfunctional valve from our patient, a case of acute severe mitral paravalvular regurgitation 16 years after implantation of CHVP.

Mitotic kinases are emerging therapeutic targets against metastatic breast cancer.

This review aims to outline mitotic kinase inhibitors' roles as potential therapeutic targets and assess their suitability as a stand-alone clinical therapy or in combination with standard treatments for advanced-stage solid tumors, including triple-negative breast cancer (TNBC). Breast cancer poses a significant global health risk, with TNBC standing out as the most aggressive subtype. Comprehending the role of mitosis is crucial for understanding how TNBC advances from a solid tumor to metastasis. Chemotherapy is the primary treatment used to treat TNBC. Some types of chemotherapeutic agents target cells in mitosis, thus highlighting the need to comprehend the molecular mechanisms governing mitosis in cancer. This understanding is essential for devising targeted therapies to disrupt these mitotic processes, prevent or treat metastasis, and improve patient outcomes. Mitotic kinases like Aurora kinase A, Aurora Kinase B, never in mitosis gene A-related kinase 2, Threonine-Tyrosine kinase, and Polo-kinase 1 significantly impact cell cycle progression by contributing to chromosome separation and centrosome homeostasis. When these kinases go awry, they can trigger chromosome instability, increase cell proliferation, and activate different molecular pathways that culminate in a transition from epithelial to mesenchymal cells. Ongoing clinical trials investigate various mitotic kinase inhibitors as potential biological treatments against advanced solid tumors. While clinical trials against mitotic kinases have shown some promise in the clinic, more investigation is necessary, since they induce severe adverse effects, particularly affecting the hematopoietic system.