Dynamic platform identifies P1 and P5 self-assembling peptides as potent breast cancer therapeutics.
Background
Enzyme-induced self-assembling peptides (EISAPs) are promising anticancer agents, but their translation is hindered by inadequate 3D tumor models. Traditional 2D cell cultures fail to replicate the complex tumor microenvironment, particularly regarding drug penetration and self-assembly dynamics. This gap limits effective screening of novel therapeutics for breast cancer, where metastatic behavior and drug resistance are significant challenges. A robust 3D model is crucial to accurately assess EISAP efficacy and optimize their therapeutic potential.
Study Design
Researchers developed a novel pillar-perfusion 3D breast cancer spheroid platform to screen a six-peptide panel (P1 (Fmoc-FF-pTyr), P2 (Fmoc-FF-pThr), P3 (RGD-FF-pTyr), P4 (NBD-FF-pTyr), P5 (Nap-FF-pTyr), and P6 (Nap-FF-pThr)). Hydrogel optimization used a 2% gelatin/1% alginate matrix for stable spheroids, while Matrigel generated invasive ones. Peptides were tested under static and dynamic flow conditions. Co-treatment experiments involved P1 with 5 μM Doxorubicin. Intratumoral penetration was assessed via fluorescence imaging of NBD-FF-pTyr. Transcriptional effects were analyzed using RT-qPCR.
Results
Among the six-peptide panel, P1 and P5 demonstrated the strongest cytotoxic effects against breast cancer spheroids, with dynamic perfusion further enhancing P1 activity, reducing viability to ~55% at 100 μM. Co-treatment of P1 with 5 μM Doxorubicin resulted in enhanced viability loss and complete inhibition of invasion, suggesting synergistic effects. Fluorescence imaging confirmed progressive intratumoral penetration and core accumulation of NBD-FF-pTyr over 5 days. RT-qPCR analysis revealed peptide- and subtype-specific transcriptional changes: P1 significantly downregulated BCL2, BRCA2, and TP53 in MCF-7 spheroids. In MDA-MB-231 spheroids, P5 produced the strongest repression of survival and DNA-repair pathways, highlighting distinct mechanisms of action across different breast cancer subtypes.
Why It Matters
This dynamic 3D pillar-perfusion platform represents a significant advancement for screening enzyme-induced self-assembling peptide therapeutics. It provides a more physiologically relevant model for assessing drug penetration, self-assembly, and treatment response, which is critical for accelerating the development of novel anticancer agents. The findings suggest that specific EISAPs like P1 and P5 hold therapeutic promise, potentially offering new strategies for breast cancer treatment, especially when combined with existing chemotherapies like Doxorubicin. This platform could help optimize peptide design and identify effective combination therapies earlier in the preclinical pipeline.