ECM-Mimetic Multiresponsive Nanobullets Targeted Against Metastasizing Circulating Tumor Clusters in Breast Cancer

Self-assembled multifunctional nanotheranostics against circulating tumor clusters in metastatic breast cancer

Circulating tumor clusters (CTC) disseminating from the primary tumor are responsible for secondary tumor formation where the conventional treatments such as chemotherapy and radiotherapy does not prevent the metastasis at locally advanced stage of breast cancer. In this study, a smart nanotheranostic system has been developed to track and eliminate the CTCs before it can colonize at a new site, which would reduce metastatic progression and increase the five-year survival rate of the breast cancer patients. Targeted multiresponsive (magnetic hyperthermia and pH) nanomicelles incorporated with NIR fluorescent superparamagnetic iron oxide nanoparticles were developed based on self-assembly for dual modal imaging and dual toxicity for spontaneous killing of CTCs in blood stream. A heterogenous tumor clusters model was developed to mimic the CTCs isolated from breast cancer patients. The nanotheranostic system was further evaluated for the targeting property, drug release kinetics, hyperthermia and cytotoxicity against developed CTC model in vitro. In vivo model in BALB/c mice equivalent to stage III and IV human metastatic breast cancer was developed to evaluate the biodistribution and therapeutic efficacy of micellar nanotheranostic system. Reduced CTCs in blood stream and low distant organ metastasis after treatment with the nanotheranostic system demonstrates its potential to capture and kill the CTCs that minimize the secondary tumor formation at distant sites.

Surface modified NIR magnetic nanoprobes for theranostic applications

Objectives: Near-Infrared based imaging modalities integrated with thermotherapy can facilitate detection of cancer at early stages and mediate high-resolution image-guided hyperthermia. In this work, fluorescent iron oxide nanoparticles (FIO) have been developed possessing deep tissue penetrable NIR imaging and site-specific magnetic hyperthermia characteristics for the elimination of cancer cells.Methods: One-pot synthesis of amine-functionalized superparamagnetic iron oxide nanoparticles (HIO) were achieved using ethylenediamine (EDA) facilitated conjugation of indocyanine green (ICG) mediated by electrostatic interactions.Results: EDA acts as a capping and reducing agent to direct the structural growth of hydrophilic Fe₃O₄ nanocrystals with high saturation magnetization, specific absorption rate, and T₂ value of 118 emu/g, 329.8 ± 5.96 W/g, and 40.17 mM^-1s^-1, respectively. Here, Fe²⁺/Fe³⁺ of two was maintained to achieve magnetite nanocrystals contradictory to the gold standard ratio of 0.5 without additives for nucleation and growth. Developed FIO showed excellent cytocompatibility even at higher concentrations and on subjecting to magnetic hyperthermia reduced its survival percentage. FIO biodistribution in mice showed enhanced half-life than free ICG with preferential localization in the brain and liver.Conclusion: Developed FIO using a facile technique is a potential clinical alternative for cellular tracking, imaging, and hyperthermia.