Boron Phenylalanine-Modified Polydopamine Nanoparticles for Targeted Delivery of Danusertib in Non-Small Cell Lung Cancer

Abstract

Non-small cell lung cancer, commonly referred to as NSCLC, remains a formidable global health challenge, characterized by high morbidity and mortality rates. A critical aspect of developing more effective therapeutic strategies involves identifying and targeting key molecular vulnerabilities within cancer cells. In this regard, Aurora-A kinase has emerged as a particularly compelling therapeutic target. Aurora-A is a serine/threonine kinase that plays a pivotal role in regulating various stages of cell division, including centrosome maturation and separation, mitotic spindle assembly, and cytokinesis. Aberrant overexpression of Aurora-A is frequently observed in a significant proportion of lung cancer cases, and its elevated expression is consistently correlated with aggressive disease progression and, unfortunately, a poor prognosis for patients. This well-established oncogenic role positions Aurora-A as a highly attractive molecular target for therapeutic intervention in the context of NSCLC treatment. This comprehensive study was specifically designed to thoroughly evaluate the therapeutic potential of a novel nanomedicine-based delivery system for Danusertib, a potent and selective small-molecule inhibitor of Aurora-A, aiming to enhance its efficacy and targeting precision in the treatment of non-small cell lung cancer.

To achieve our objectives, a sophisticated nanocarrier system was engineered utilizing boron phenylalanine (BPA)-modified polydopamine (PDA). Polydopamine, a synthetic melanin-like polymer, offers exceptional biocompatibility, biodegradability, and inherent capabilities for drug loading and near-infrared absorption, making it an ideal platform for biomedical applications. The incorporation of boron phenylalanine was strategic, aiming to confer enhanced tumor-targeting capabilities, given the propensity of many cancer cells to selectively uptake boron-containing compounds. This modified PDA served as the foundational carrier material to efficiently encapsulate Danusertib, thereby leading to the successful preparation of the B-PDA@Danu nanoparticles. Following their synthesis, these novel nanoparticles underwent rigorous and comprehensive characterization. This meticulous process involved assessing their structural integrity, elucidating their precise microstructure and morphology, accurately determining their average particle size and size distribution, and measuring their zeta potential, a crucial indicator of nanoparticle surface charge and colloidal stability. Furthermore, their stability under various physiological conditions, their drug loading capacity (the maximum amount of Danusertib that could be incorporated), their drug loading rate (the efficiency of incorporation), and their in vitro drug release profile (how the drug is released over time) were all thoroughly evaluated. Moving beyond physicochemical characterization, the therapeutic effects of B-PDA@Danu were investigated through a series of robust in vitro studies using A549 lung cancer cells, a widely recognized model for NSCLC research. These experiments precisely assessed the nanoparticles’ impact on cellular viability, their ability to induce apoptosis (programmed cell death), their efficiency in facilitating cellular uptake, and their influence on the various phases of the cell cycle. Subsequently, the efficacy and safety of B-PDA@Danu were meticulously explored in preclinical in vivo models. This involved initially examining their biodistribution and anti-tumor effects in a subcutaneous xenograft tumor model in mice, providing a general assessment of efficacy and systemic safety. Following this, a more sophisticated and clinically relevant mouse lung carcinoma in situ model was employed to specifically study the in vivo distribution and targeted anti-tumor effects of B-PDA@Danu directly within the lung microenvironment where NSCLC typically originates and progresses.

The results obtained from our rigorous experimentation provided compelling evidence for the efficacy and favorable characteristics of the synthesized nanoparticles. The B-PDA@Danu nanoparticles exhibited a highly uniform spherical morphology, demonstrating excellent structural integrity, and carried a negative surface charge, contributing to their colloidal stability in biological media. Their average particle size was precisely measured at 172.96 ± 1.61 nanometers, a size range generally considered optimal for passive tumor accumulation via the enhanced permeability and retention (EPR) effect and for efficient cellular uptake. Beyond these physical attributes, the nanoparticles demonstrated remarkable stability in various buffers and physiological solutions, indicating their potential for sustained circulation in vivo. Crucially, they exhibited an impressive capacity for efficiently loading Danusertib, ensuring that a significant amount of the therapeutic agent could be delivered per nanoparticle. Furthermore, their in vitro release profile demonstrated a controlled and sustained release of Danusertib, suggesting prolonged therapeutic availability. In vitro cellular studies yielded highly encouraging results: B-PDA@Danu nanoparticles significantly promoted their uptake by A549 lung cancer cells, indicating effective cellular delivery of the drug. Consequentially, this led to a potent inhibition of cell viability, with statistical significance confirming a profound cytotoxic effect (P < 0.001). Mechanistically, the nanoparticles induced a pronounced G2/M cell cycle arrest (P < 0.001), preventing cancer cells from proceeding through division, and simultaneously, they significantly increased the rate of apoptosis (P < 0.001), actively eliminating cancerous cells through programmed cell death pathways. Translating these promising in vitro findings to living systems, studies conducted in the subcutaneous xenograft tumor model unequivocally demonstrated that B-PDA@Danu nanoparticles robustly suppressed tumor growth, leading to a statistically significant reduction in tumor volume (P < 0.001). This anti-tumor effect was directly correlated with the induction of cell cycle arrest within the tumor cells themselves (P < 001), confirming the nanoparticles’ targeted mechanistic action. Furthermore, histological analysis revealed clear evidence of tumor tissue damage, indicating effective eradication of cancerous cells. Importantly, these therapeutic benefits were observed alongside a favorable safety profile, as B-PDA@Danu exhibited good biosafety with minimal signs of systemic toxicity in the animal model. The most compelling evidence for targeted delivery came from the mouse lung carcinoma in situ model. In this highly relevant preclinical setting, B-PDA@Danu nanoparticles demonstrated exceptional ability to specifically target and accumulate at the site of carcinogenesis within the lung, showcasing their precise tumor-homing capabilities. This highly localized accumulation led directly to a discernible and significant shrinkage of the established lung tumors, underscoring the potential for precise therapeutic intervention.

In conclusion, the findings from this comprehensive investigation strongly indicate that B-PDA@Danu represents a novel and highly promising nanomedicine-based approach for the treatment of non-small cell lung cancer. This innovative therapeutic strategy leverages the unique advantages of nanotechnology to enable targeted elimination of tumor cells, thereby maximizing therapeutic efficacy while simultaneously minimizing off-target effects and systemic toxicity. This dual benefit of precise targeting and low potential toxicity positions B-PDA@Danu as a significant advancement in the pursuit of more effective and safer anti-NSCLC therapies with potential for future clinical translation.