A Cleverly Designed Novel Lipid Nanosystem: Targeted Retention, Controlled Visual Drug Release, and Cascade Amplification Therapy for Mammary Carcinoma in vitro

Objective

To construct an ideal theranostic nanoplatform (LIP3); to clarify its physicochemical properties; to confirm its characteristics of dual-modality imaging, active-targeting, and cascade amplification therapy for mammary carcinoma; and to perform a preliminary exploration of the cytotoxicity mechanism.

Design

A self-prepared liposome nanosystem, LIP3, can actively target 4T1 cells because the surface is linked with C-RGD. Haematoporphyrin monomethyl ether (HMME), an excellent sonosensitizer entrapped in the lipid bilayer, can function in photoacoustic imaging. Low-intensity focused ultrasound (LIFU) of ultrasound-targeted microbubble destruction (UTMD) promotes localized drug delivery into tumours because PFH, a phase-change substance, is loaded in the LIP3 core, achieving visualization of targeted drug release, and sonodynamic therapy (SDT) can kill tumour cells. SDT provides a favourable environment for AQ4N, resulting in amplification of LIP3 treatment. Therefore, LIP3 shows targeted aggregation and targeted release, integrating dual-mode imaging and precise treatment.

Results

The self-prepared lipid nanosystem, LIP3, meets the above expectations and has ideal physicochemical properties, with a regular sphere with uniform distribution. Contrast-enhanced ultrasound (CEUS), photoacoustic imaging, and bimodal imaging were effective in vitro. In 4T1 cell experiments, the cell capacity was as high as 42.9%, and the cytotoxicity to 4T1 was more than 5 times that of LIP1 (containing AQ4N only) and more than 2 times that of LIP2 (containing only HMME), achieving comparable results as cascade therapy for mammary cancer.

Conclusion

LIP3, a theranostic nanoplatform, was successfully constructed and conformed to the physicochemical characterization of ideal nanoparticles, with active-targeting, dual-modality imaging, visualized drug release, and precise treatment under the action of LIFU. SDT provides a favourable environment for AQ4N, resulting in amplification of LIP3 treatment. Therefore, LIP3 shows targeted aggregation and targeted release, integrating dual-mode imaging, and precise cascade treatment. This unique theranostic NPS with multiple capabilities is expected to be a favourable anti-cancer method in the future.

Nanoparticle-assisted ultrasound: A special focus on sonodynamic therapy against cancer

At present, ultrasound radiation is broadly employed in medicine for both diagnostic and therapeutic purposes at various frequencies and intensities. In this review article, we focus on therapeutically-active nanoparticles (NPs) when stimulated by ultrasound. We first introduce the different ultrasound-based therapies with special attention to the techniques involved in the oncological field, then we summarize the different NPs used, ranging from soft materials, like liposomes or micro/nano-bubbles, to metal and metal oxide NPs. We therefore focus on the sonodynamic therapy and on the possible working mechanisms under debate of NPs-assisted sonodynamic treatments. We support the idea that various, complex and synergistics physical-chemical processes take place during acoustic cavitation and NP activation. Different mechanisms are therefore responsible for the final cancer cell death and strongly depends not only on the type and structure of NPs or nanocarriers, but also on the way they interact with the ultrasonic pressure waves. We conclude with a brief overview of the clinical applications of the various ultrasound therapies and the related use of NPs-assisted ultrasound in clinics, showing that this very innovative and promising approach is however still at its infancy in the clinical cancer treatment.