The association between microRNAs and various diseases, especially cancer, has been established in recent years, indicating that miRNAs can potentially serve as biomarkers for these diseases. Determining miRNA concentrations in biological samples is crucial for disease diagnosis. Nevertheless, the stem-loop reverse transcription quantitative PCR method, the gold standard for detecting miRNA, has great challenges in terms of high costs and enzyme limitations when applied to clinical biological samples. In this study, an isothermal signal amplification method based on a duplex-specific nuclease (DSN) enzyme-driven DNA walker and an improved catalytic hairpin assembly (CHA) was designed for miRNA detection. First, biotin–triethylene glycol-modified trigger-releasable DNA probes were conjugated to the streptavidin-coated magnetic beads for recognizing the target miRNA. The DSN enzyme specifically hydrolyzes DNA strands when the DNA probe hybridizes with the targeted miRNA. This recycling process converts the input miRNA into short trigger fragments (catalysts). Finally, three hairpins of improved CHA are driven by this catalyst, resulting in the three-armed CHA products and a fluorescence signal as the output. This dual-cycle biosensor shows a good linear relationship in the detection of miR-21 and miR-141 over the final concentration range of 250 fM to 50 nM, presenting an excellent limit of detection (2.95 amol). This system was used to detect miR-21 and miR-141 in MCF-7 and 22RV1 cells, as well as in 1% human serum. This system can be used to evaluate the expression levels of miRNAs in different biological matrices for the clinical diagnosis and prognosis of different cancers.

The objective of this study was to enhance the membrane permeability and anticancer effectiveness of (20S)-protopanaxadiol (PPD) by introducing triphenylphosphonium into the OH group at the C-3 site. This study shows that the anti-proliferation activity of CTPPPPD, with an IC50 value of 1.65 ± 0.10 μmol/L, was 33-times better than that of PPD (with an IC50 value of 54.56 ± 4.56 μmol/L) and superior to that of cisplatin (with an IC50 value of 1.82 ± 0.25 μmol/L) against A549 cells. Biological examinations suggested that CTPPPPD treatment reduced the growth rate of A549 cells, increased the permeability of cell membranes, and changed the structure of chromosomal DNA in a concentration-dependent manner. Annexin V/PI assay and flow cytometry were employed to detect the effect of CTPPPPD on the apoptosis of A549 cells. The results showed that CTPPPPD could induce the apoptosis of A549 cells, and the apoptosis rate of A549 cells treated with 0, 1.0, 2.0, and 4.0 μM of CTPPPPD for 24 h was 0%, 4.9%, 12.7%, and 31.0%, respectively. The integration of transcriptomics and metabolomics provided a systematic and detailed perspective on the induced antitumor mechanisms. A combined analysis of DEGs and DAMs suggested that they were primarily involved in the central carbon metabolism pathway in cancer, as well as the metabolism of aminoacyl-tRNA biosynthesis, alanine, aspartate, and glutamate. Central carbon metabolism in cancer-related genes, i.e., SLC16A3, FGFR3, LDHA, PGAM1, and SLC2A1, significantly reduced after treatment with CTPPPPD. In particular, the dominant mechanism responsible for total antitumor activity may be attributed to perturbations in the PI3K-AKT, MAPK, and P53 pathways. The findings derived from transcriptomics and metabolomics were empirically confirmed through q-PCR and molecular docking. Further analyses revealed that CTPPPPD could be a promising lead for the development of protopanaxadiol for non-small-cell lung cancer (NSCLC) drugs.