Triple-negative breast cancer (TNBC) lacks three important receptors, ER, PR, and HER2. It is more aggressive and more likely to relapse after treatment, thus has been identified as one of the most malignant breast cancer types. The development of efficient targeted TNBC therapy is an important research topic in TNBC treatment. We report the development of a new aptamer–drug conjugate (ApDC), AS1411–triptolide conjugate (ATC), as targeted therapy for the treatment of TNBC with high efficacy. The conjugate possesses excellent specificity and high cytotoxicity against the MDA-MB-231 cell line. The advantages of our newly invented ATC are further highlighted by its excellent in vivo anti-TNBC efficacy and negligible side effects toward healthy organs.

Because altered microRNAs (miRNAs) expression patterns have been observed in a variety of diseased tissues, miRNA expression was compared in human cervical cancer tissues relative to adjacent normal cervical tissues in the present study. Microarray chips with 924 probes were used to detect the expression of miRNAs in cervical cancer tissue and adjacent normal cervical tissue of 13 patients with cervical cancer (11 squamous cervical cancers, one cervical adenocarcinoma, and one cervical sarcoma), all of whom were infected with human papilloma virus (HPV) 16 and/or HPV18. Compared to the expression levels in normal cervical tissues, 18 miRNAs (1.9%) were significantly upregulated (increase of ≥2×), and 19 miRNAs (2.1%) were significantly downregulated (decrease of ≤0.5×) in cervical cancer tissues. miRNA expression was independent of lymph node involvement, vascular invasion, and pathological differentiation. Taken together, cervical cancer tissues have altered expression of miRNAs relative to adjacent normal tissues. Further studies are necessary to determine whether aberrant miRNA expression is related to the pathogenesis of cervical cancer.

Aptamers and antibodies, as molecular recognition probes, play critical roles in cancer diagnosis and therapy. However, their recognition ability is based on target overexpression in disease cells, not target exclusivity, which can cause on-target off-tumor effects. To address the limitation, we herein report a novel strategy to develop a conditional aptamer conjugate which recognizes its cell surface target, but only after selective activation, as determined by characteristics of the disease microenvironment, which, in our model, involve tumor hypoxia. This conditional aptamer is the result of conjugating the aptamer with PEG5000-azobenzene-NHS, which is responsive to hypoxia, here acting as a caging moiety of conditional recognition. More specifically, the caging moiety is unresponsive in the intact conjugate and prevents target recognition. However, in the presence of sodium dithionite or hypoxia (<0.1% O2) or in the tumor microenvironment, the caging moiety responds by allowing conditional recognition of the cell-surface target, thereby reducing the chance of on-target off-tumor effects. It is also confirmed that the strategy can be used for developing a conditional antibody. Therefore, this study demonstrates an efficient strategy by which to develop aptamer/antibody-based diagnostic probes and therapeutic drugs for cancers with a unique hypoxic microenvironment.

No abstract