Hypomethylation of ATP1A1 Is Associated with Poor Prognosis and Cancer Progression in Triple-Negative Breast Cancer.

Dysregulated DNA methylation in cancer is critical in the transcription machinery associated with cancer progression. Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, but no treatment targeting TNBC biomarkers has yet been developed. To identify specific DNA methylation patterns in TNBC, methyl-binding domain protein 2 (MBD) sequencing data were compared in TNBC and the three other major breast cancer subtypes. Integrated analysis of DNA methylation and gene expression identified a gene set showing a correlation between DNA methylation and gene expression. ATPase Na+/K+-transporting subunit alpha 1 (ATP1A1) was found to be specifically hypomethylated in the coding sequence (CDS) region and to show increased expression in TNBC. The Cancer Genome Atlas (TCGA) database also showed that hypomethylation and high expression of ATP1A1 were strongly associated with poor survival in patients with TNBC. Furthermore, ATP1A1 knockdown significantly reduced the viability and tumor-sphere formation of TNBC cells. These results suggest that the hypomethylation and overexpression of ATP1A1 could be a prognostic marker in TNBC and that the manipulation of ATP1A1 expression could be a therapeutic target in this disease.

Anti-SARS-CoV-2 Neutralizing Antibody Responses after Two Doses of ChAdOx1 nCoV-19 vaccine (AZD1222) in Healthcare Workers.

BACKGROUND: The kinetics of neutralizing antibodies against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) play an important role in evaluating vaccine efficacy and durability, herd immunity, additional vaccination, and prediction models of immune protection against coronavirus disease 2019. MATERIALS AND METHODS: Serum collection times were 4 and 8 weeks after 1st inoculation of AZD1222 (AstraZeneca, Cambridge, UK), and 2 and 16 weeks after 2nd inoculation with 12-week dosing intervals. Neutralizing antibody (Nab) titers were measured indirectly using commercially available R-FIND SARS-CoV-2 Neutralizing Antibody ELISA Kit (SG Medical Inc., Seoul, Korea). Possible influences of gender, age, and adverse events on neutralizing antibody titer were also investigated. RESULTS: Nab titers (median inhibition %) started to decrease shortly after reaching peaks. This decrease was more pronounced in the elderly group (≥56 years) than in the young group (≤39 years) at 8 weeks (49.5% vs. 55.4%, P = 0.021) and 16 weeks (40.6% vs. 53.9%, P = 0.006) after the 1st and 2nd inoculation. And Nab titers were inversely correlated with age in the 8-week (r = -0.2091, P = 0.0284) and the 28-week group (r = -0.2811, P = 0.0029). Seropositive conversion of Nab reached 89.1% and 100% following 1st and 2nd inoculation. This 100% seropositivity was dropped sharply to 74.5% after 16 weeks. Compared to subjects without adverse events (51.8%), median inhibition was higher in subjects with one or more systemic adverse events (74.2%, P = 0.0203) or those with one or more local and systemic adverse events (77.1%, P = 0.0003). CONCLUSION: Nab induced by AZD1222 (AstraZeneca, UK) vaccination started to degrade shortly after the production period. Nab titers were lower in the elderly than in younger group during the degradation period. This seems to be because the degradation process of Nab is more pronounced in the elderly. This may explain why the frequency of breakthrough infections, disease severity, and mortality were higher in the elderly and may require revaccination to ensure robust immunity.

Reduced miR-371b-5p expression drives tumor progression via CSDE1/RAC1 regulation in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer; however, specific prognostic biomarkers have not yet been developed. In this study, we identified dysregulated microRNAs (miRNAs) in TNBC by profiling miRNA and mRNA expression. In patients with TNBC, miR-371b-5p expression was reduced, and miR-371b-5p overexpression significantly mitigated TNBC cell growth, migration, and invasion. In addition, we found that expression of cold shock domain-containing protein E1 (CSDE1), a direct target gene of miR-371b-5p, was upregulated in TNBC cells, and inhibition of CSDE1 expression alleviated TNBC cell growth by regulating RAC1 transcription. Mechanistically, CSDE1, phosphorylated C-terminal domain (p-CTD) of RNA polymerase II (RNAPII), and CDK7 form a complex, and downregulation of CSDE1 leads to weak interaction between RNAPII p-CTD and CDK7, resulting in a decrease in RNAPII p-CTD expression to reduce RAC1 transcript levels in CSDE1-deficient TNBC cells. Our data demonstrate that miR-371b-5p is a tumor-suppressive miRNA that regulates the CSDE1/Rac1 axis and could be a potential prognostic biomarker for TNBC.

Inhibition of Chk1 by miR-320c increases oxaliplatin responsiveness in triple-negative breast cancer.

Checkpoint kinase 1 (Chk1) expression is enhanced in most cancers owing to oncogenic activation and constant replicative stress. Chk1 inactivation is a promising cancer therapy, as its inactivation leads to genomic instability, chromosomal catastrophe, and cancer cell death. Herein, we observed that miR-320c, downregulated in triple-negative breast cancer (TNBC) patients, can target Chk1. In addition, downregulated miR-320c expression was associated with poor overall survival in TNBC patients. As Chk1 was associated with the DNA damage response (DDR), we investigated the effect of miR-320c on DDR in TNBC cells. To induce DNA damage, we used platinum-based drugs, especially oxaliplatin, which is most effective with miR-320c. We observed that overexpression of miR-320c in TNBC regulated the oxaliplatin responsiveness by mediating DNA damage repair through the negative regulation of Chk1 in vitro. Furthermore, using a xenograft model, a combination of miR-320c mimic and oxaliplatin effectively inhibited tumor progression. These investigations indicate the potential of miR-320c as a marker of oxaliplatin responsiveness and a therapeutic target to increase the efficacy of chemotherapy in TNBC.

miR-374a-5p promotes tumor progression by targeting ARRB1 in triple negative breast cancer.

Triple negative breast cancer (TNBC) has higher aggressiveness and poorer outcomes compared with other subtypes of breast cancer. However, the genomic and molecular aberrations of TNBC are largely unknown. In this study, miR-374a-5p was discovered as a novel TNBC-specific miRNA and its functions and the molecular mechanisms involved were investigated. Combined gene expression profiling of miRNA-microarray and human transcriptome dataset analysis revealed that miR-374a-5p is specifically upregulated in TNBC patients. Functional studies using in vitro and in vivo models indicated that upregulated miR-374a-5p promotes tumor progression in TNBC. miR-374a-5p was also found to directly target arrestin beta 1 (ARRB1) that is specifically downregulated in TNBC patients in several human genomic datasets. Overexpressed ARRB1 reduced TNBC cell growth and migration, and the ARRB1 expression level is inversely correlated with the histological grade of the breast cancer and positively associated with TNBC patient survival, suggestive of a tumor-suppressive function of ARRB1 in breast cancer. Interestingly, increased ARRB1 activates AMPK in TNBC cells, associated with the expression of miR-374a-5p. Taken together, the findings suggest that miR-374a-5p is a potential prognostic marker of TNBC.

Fabrication of triple-layered magnetite/hydrogel/quantum dots via the molecular linkage of bi-functional diamines.

A multifunctional biomedical agent with magnetism, pH-sensitive, fluorescent properties was fabricated as a triple-layered magnetite/hydrogel/quantum dots. First, core-shell magnetic silica nanospheres (Fe3O4@SiO2) were synthesized via the sol-gel reaction of magnetite clusters with tetraethyl orthosilicate (TEOS), and the resuting magnetic particles were encapsulated with poly(N-isopropylacrylamide-co-acrylic acid) hydrogels through a free radical polymerization. The hydrogel-encapsulated magnetic particles were subsequently anchored by quantum dots (QDs) via the molecular linkage of bi-functional diamines. Diamine molecules effecrively induced the crosslinking between magnetic hydrogels and quantum dots. Among diamine linkers with different chain lengths (C-4, C-8, and C-12), C-8 diamine (1,8-diaminooctane) produced the maximal PL intensity for QD-bound hydrogels, indicating that C-8 diamine was an optimal cross-linker between hydrogels and QDs with surface carboxylic acid groups. The characteristic properties of the multifunctional nanocomposites were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), zeta-potential meter, and photoluminescence (PL) spectroscopy.

Fabrication of triple-layered magnetite-hydrogel-gold nanocomposites for biomedical applications.

Magnetite-hydrogel-gold nanocomposites with optical-active, thermo-responsive, and magnetism have been prepared by the following consecutive steps. Hydrogel-encapsulated magnetites were first synthesized by the combination of sol-gel reaction and radical polymerization process, and the resulting magnetic hydrogels were subsequently bound with nano-sized Au (1-3 nm) via a molecular linkage of diamine ligand which was covalently bonded to the carboxylic groups on the hydrogel surface. Au seeds anchored on the magnetic hydrogels were further reduced into nano-scale Au layer which induced the distinct red-shift of absorption band into NIR region. The optical properties and surface morphology of the nanocomposites were characterized by UV-vis spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

Fabrication of magnetite-hydrogel nanocomposites with clustered magnetite cores and poly(N-isopropylacrylamide-co-acrylic acid) shells for drug delivery application.

Magnetite-hydrogel nanocomposites were fabricated through the combination of sol-gel process and radical polymerization. The incorporation of magnetite clusters into silica matrix was facilely conducted by the sol-gel reaction of APTMS-complexed CMNPs (citrate-stabilized magnetites) and tetraethoxysilane (TEOS) in ethanol solution. The core-shell magnetic nanoparticles were further encapsulated with poly(N-isopropylacrylamide-co-acrylic acid) hydrogeals via a free radical polymerization. The magnetic nanoparticles exhibited superparamagnetic characteristics with negligible remanence and coercivity. Hydrogel-encapsulated magnetic nanoparticles showed systematic changes of particle size corresponding to the alteration of pH and temperature. The resulting nanocomposites can be a smart drug delivery agent with magnetic and stimuli (pH, temperature)-sensitive properties.