Targeted delivery of Dbait by an artificial extracellular vesicle for improved radiotherapy sensitivity of esophageal cancer.

Intensification of radiotherapy has been shown to be an effective way for improving the therapeutic efficacy of radiation sensitive malignancies such as esophageal cancer (EC). The application of DNA Bait (Dbait), a type of DNA repair inhibitor, is an emerging strategy for radiosensitization. In this study, a Eca-109 cancerous cytomembrane-cloaked biomimetic drug delivery system (DDS), CMEC-Dbait, was designed and successfully fabricated, for targeted delivery of Dbait. Our systematic evaluation demonstrated that the ingenious artificial gastrointestinal extracellular vesicle owns neat spherical structure, proper particle size (154.6±5.5 nm) and surface charge (2.6±0.3 mV), favourable biocompatibility and immunocompatibility, being conducive to in vivo drug delivery. Besides, Eca-109 cytomembrane coating endowed CMEC-Dbait with effective targeting ability to homologous EC cells. Owing to these advantages, the biomimetic DDS was proved to be a potent radiosensitizer in vitro, indicated by remarkably reduced cell viability and enhanced cellular apoptosis by the combination therapy of radiation and CMEC-Dbait. The result was validated in vivo using mouse xenograft models of EC, the results illustrated that radiotherapy plus CMEC-Dbait significantly suppressed tumor growth and prolonged survival of tumor bearing mice. Western blotting results showed that CMEC-Dbait can significantly inhibit DNA damage repair signaling pathways by simulating DNA double-strand breaks both in and ex vivo. In conclusion, the versatile biomimetic CMEC-Dbait was characterized of low toxicity, excellent biocompatibility and satisfactory drug delivery efficiency, which is confirmed to be an ideal radiosensitizer for homologous cancer and merits further investigation in both pre-clinical and clinical studies.

Targeted delivery of a PROTAC induced PDEδ degrader by a biomimetic drug delivery system for enhanced cytotoxicity against pancreatic cancer cells.

Pancreatic carcinoma (PC) has one of the highest mortality-to-incidence ratios of any solid tumor worldwide. Although KRAS mutation is commonly found in 95% of PCs, directly targeting KRAS remains to be a highly challenging task because of its lacking catalytic pockets where molecule inhibitors can bind with. Proteolysis-targeting chimeric (PROTAC) represents an effective approach for specific degradation of disease-causing proteins by hijacking the endogenous ubiquitin-proteasome system (UPS). Previously, we designed a first-in-class PROTAC induced PDEδ degrader (PIPD), which demonstrated improved anti-tumor efficacy against KRAS mutant malignancies. However, translating cellular degradative effects from bench to beside remains a highly challenging task because of PROTAC's poor penetration efficiency across target cytomembranes and non-targeting delivery induced undesired "off target" side-effects. Herein, a smart nano-drug delivery system (CM8988-PIPD) was successfully constructed by biomimetic strategy for targeted delivery of PIPD. The biomimetic nanoparticle showed well-defined regular spherical structure with an average particle size of approximately 124.8 nm. Cancer cytomembrane camouflage endows CM8988-PIPD with excellent in vivo serum stability, controlled drug release profile, favorable biocompatibility & immunocompatibility, and prominent targeting ability to homologous PC cells. Owing to these advantages, the smart DDS significantly enhanced PDEδ degrading efficacy, resulting in induced cellular apoptosis (more than 50% for both PC cells) and suppressed cell proliferation via the inhibition of RAS signaling. In vitro studies illustrated that CM8988-PIPD hold great potential for the treatment of PC, which merits further investigation in both pre-clinical and clinical investigations in the future.

A highly efficient protocol for transforming Cuscuta reflexa based on artificially induced infection sites.

The parasitic plant genus Cuscuta is notoriously difficult to transform and to propagate or regenerate in vitro. With it being a substantial threat to many agroecosystems, techniques allowing functional analysis of gene products involved in host interaction and infection mechanisms are, however, in high demand. We set out to explore whether Agrobacterium-mediated transformation of different plant parts can provide efficient alternatives to the currently scarce and inefficient protocols for transgene expression in Cuscuta. We used fluorescent protein genes on the T-DNA as markers for transformation efficiency and transformation stability. As a result, we present a novel highly efficient transformation protocol for Cuscuta reflexa cells that exploits the propensity of the infection organ to take up and express transgenes with the T-DNA. Both, Agrobacterium rhizogenes and Agrobacterium tumefaciens carrying binary transformation vectors with reporter fluorochromes yielded high numbers of transformation events. An overwhelming majority of transformed cells were observed in the cell layer below the adhesive disk's epidermis, suggesting that these cells are particularly susceptible to infection. Cotransformation of these cells happens frequently when Agrobacterium strains carrying different constructs are applied together. Explants containing transformed tissue expressed the fluorescent markers in in vitro culture for several weeks, offering a future possibility for development of transformed cells into callus. These results are discussed with respect to the future potential of this technique and with respect to the special characteristics of the infection organ that may explain its competence to take up the foreign DNA.