Amphipathic Small Molecule AZT Compound Displays Potent Inhibitory Effects in Cancer Cell Proliferation

In Situ Super-Resolution Imaging of Telomeres with DNA-PAINT

Telomeres are located at the ends of chromosomes and play an important role in maintaining the integrity of chromosomes and controlling the cycle of cell division. Studies have shown that abnormal telomere length may lead to the occurrence of some diseases. Therefore, accurate measurement of telomere length will be helpful for the prediction and diagnosis of related diseases. DNA point accumulation for imaging in nanoscale topography (PAINT) is an optical super-resolution technology that relies on the instantaneous binding of the fluorescent DNA imaging strand to the target epitope. Here, we present the first demonstration of DNA-PAINT-based in situ super-resolution imaging of telomeres as well as centromeres. For DNA-PAINT imaging, Cy5-labeled telomere DNA (5'-Cy5-TTTTTCCCTAACCCTAA-3') and Cy3-labeled centromere DNA (5'-Cy3-TTTTTAGCTTCTGTCTAGTTT-3') are utilized as the imager strands. Through an improved permeabilization strategy that we proposed, the imager strands can bind with intracellular telomeres and centromeres with high specificity, realizing super-resolution imaging of telomeres and centromeres. To check the applicability of DNA-PAINT in evaluating telomere length, we conducted an experiment using azidothymidine (AZT)-treated tumor cells as the imaging target. The DNA-PAINT imaging results clearly revealed the telomerase inhibition effect of AZT. Compared with single-molecule localization microscopy (SMLM) with peptide nucleic acid (PNA)-based fluorescence in situ hybridization (FISH), our method has the advantages of low cost, low toxicity, and simple equipment. Such a DNA-PAINT-based imaging strategy holds great potential in measuring telomere length with high accuracy, which would play an important role in the study of telomere-related diseases such as cancer.

An investigation of Plk1 PBD inhibitor KBJK557 as a tumor growth suppressor in non-small cell lung cancer

Lung cancer is the second most commonly reported type of cancer worldwide. Approximately 80–85% of lung cancer occurrences are accounted by non-small cell lung cancer (NSCLC). Polo-like kinase-1 (Plk1) plays multiple roles in cell cycle progression and its overexpression is observed in majority of malignancies, including NSCLC. A combination of frontline drugs and inhibitors targeting the Plk kinase domain (KD) has been used to overcome drug resistance in NSCLC. Plk1 KD inhibitors are highly prone to cross-reactivity with similar kinases, eventually leading to undesirable side effects. Moreover, there have been no reports of Plk1 PBD inhibitors showing antitumorigenic effects on NSCLC cells or animal models so far. To address this issue herein, for the first time, our recently reported Plk1 PBD inhibitor KBJK557 was evaluated for the anticancer potential against NSCLC cells. KBJK557 displayed notable cytotoxic effects in A549, PC9, and H1975 cells. Mechanistic investigations revealed that KBJK557-treated cells underwent G2/M cell cycle arrest, triggering subsequent apoptosis. In vivo antitumorigenic activity in xenograft mice model demonstrates that KBJK557-treated mice showed a considerable decrease in tumor size, proving the significances of Plk1 in lung cancer. Collectively, this study demonstrates that KBJK557 can serve as a promising drug candidate for treating the lung cancer through Plk1 PBD inhibition.

Development of the H3N2 influenza microneedle vaccine for cross-protection against antigenic variants

Due to the continuously mutating nature of the H3N2 virus, two aspects were considered when preparing the H3N2 microneedle vaccines: (1) rapid preparation and (2) cross-protection against multiple antigenic variants. Previous methods of measuring hemagglutinin (HA) content required the standard antibody, thus rapid preparation of H3N2 microneedle vaccines targeting the mutant H3N2 was delayed as a result of lacking a standard antibody. In this study, H3N2 microneedle vaccines were prepared by high performance liquid chromatography (HPLC) without the use of an antibody, and the cross-protection of the vaccines against several antigenic variants was observed. The HA content measured by HPLC was compared with that measured by ELISA to observe the accuracy of the HPLC analysis of HA content. The cross-protection afforded by the H3N2 microneedle vaccines was evaluated against several antigenic variants in mice. Microneedle vaccines for the 2019–20 seasonal H3N2 influenza virus (19–20 A/KS/17) were prepared using a dip-coating process. The cross-protection of 19–20 A/KS/17 H3N2 microneedle vaccines against the 2015–16 seasonal H3N2 influenza virus in mice was investigated by monitoring body weight changes and survival rate. The neutralizing antibody against several H3N2 antigenic variants was evaluated using the plaque reduction neutralization test (PRNT). HA content in the solid microneedle vaccine formulation with trehalose post-exposure at 40℃ for 24 h was 48% and 43% from the initial HA content by HPLC and ELISA, respectively. The vaccine was administered to two groups of mice, one by microneedles and the other by intramuscular injection (IM). In vivo efficacies in the two groups were found to be similar, and cross-protection efficacy was also similar in both groups. HPLC exhibited good diagnostic performance with H3N2 microneedle vaccines and good agreement with ELISA. The H3N2 microneedle vaccines elicited a cross-protective immune response against the H3N2 antigenic variants. Here, we propose the use of HPLC for a more rapid approach in preparing H3N2 microneedle vaccines targeting H3N2 virus variants.