CD30 is highly expressed on Hodgkins lymphoma and anaplastic large cell lymphoma, making it an attractive target for therapy. We describe the generation of serum-stabilized ssDNA aptamers that bind CD30 via a hybrid SELEX methodology. The selected aptamer bound CD30 with high affinity and specificity. Further optimization of the aptamer led to a short, truncated variant with a 50-fold higher affinity than its longer counterpart. The multivalent aptamer was able to induce oligomerization of CD30 receptors and, in effect, activate downstream signaling, which lead to apoptosis of ALCL cells. Immunotherapy using aptamer-based co-stimulation provides an alternative to antibodies, and has potential to transform cancer treatment.

As a “chemical antibody”, oligonucleotide aptamers can specifically bind to their target molecules. However, clinical potential of aptamers in disease diagnosis is not yet fully explored. Using a tumor cell-based selection protocol, we developed single-stranded DNA aptamers for Hodgkin lymphoma (HL) tumor cells. The aptamers specifically bound to HL cells with a high affinity, reaching maximal cell binding at 10 nM final concentration. Importantly, the aptamers were able to selectively detect HL cells and did not react to other tumor or blood cells in mixed samples, indicating that the aptamers can be used as a specific probe for in vitro analysis of HL cells. Moreover, due to the inherent properties of DNA, the aptamers were stable in human serum, suggesting potential for in vivo detection of HL tumor cells.

CD30 is a biomarker for diagnosis and targeted therapy of Anaplastic Large cell lymphoma (ALCL) and Classical Hodgkin Lymphoma (CHL). Our previous studies have demonstrated specific binding of RNA aptamer to CD30 positive tumor cells. However, for in vivo targeted therapy there is a concern about biostability of the RNA aptamers.To overcome this, an ssDNA aptamer was developed via a hybrid SELEX approach using CD30‐expresing lymphoma cells and purified CD30 protein to yield the aptamer C2NP which specifically bound to CD30 expressing ALCL and CHL cells at concentrations ≤10 nm and did not react to control tumor cells. Importantly, C2NP is highly stable and more than 50% of them remained after incubation in human serum at 37°C for 24 hours, indicating the suitability for in vivo use.For targeted therapy study, C2NP was conjugated with a chemotherapeutic agent and a fluorescent reporter to form an aptamer‐drug conjugate (ADC). The specificity of ADC was confirmed by flow cytometry and intracellular delivery of chemo‐drug was observed by microscopy. Chemical conjugation of drug had no effect on aptamer binding specificity and affinity to lymphoma cells. In addition, potential therapeutic effects of the aptamer‐drug conjugate are under investigation by using cultured ALCL and CHL cell‐lines currently. This is the first study to use an aptamer‐drug conjugate for targeted therapy of CD30‐exprssing lymphomas.