Long-acting tunable release of amlodipine loaded PEG-PCL micelles for tailored treatment of chronic hypertension.

Hypertension is a chronic condition that requires lifelong therapeutic management. Strict adherence to drug administration timing improves efficacy, while poor adherence leads to safety concerns. In light of these challenges, we present a nanofluidic technology that enables long-acting drug delivery with tunable timing of drug administration using buried gate electrodes in nanochannels. We developed a poly(ethylene glycol) methyl ether-block-poly(ε-caprolactone) (PEG-PCL)-based micellar formulation of amlodipine besylate, a calcium channel blocker for hypertension treatment. The electrostatically charged PEG-PCL micellar formulation enhanced drug solubility and rendered amlodipine responsive to electrostatic release gating in nanochannels for sustained release at clinically relevant therapeutic dose. Using a low-power (<3 VDC) gating potential, we demonstrated tunable release of amlodipine-loaded micelles. Additionally, we showed that the released drug maintained biological activity via calcium ion blockade in vitro. This study represents a proof of concept for the potential applicability of our strategy for chronotherapeutic management of hypertension.

Quantification of natural killer cell polarization and visualization of synaptic granule externalization by imaging flow cytometry.

Defining immunological mechanisms underlying NK cell biology is crucial for the treatment and prevention of immune deficiency and malignancy. The limited availability of human biological specimens presents a challenge to the study of human immunobiology. The use of high throughput, multi-parametric assays will not only aid in the definition and diagnosis of complex human immune disorders affecting NK cell function but also advance NK cell biology through population-based assessment of molecular signaling. In an effort to garner the most information from limited numbers of human cells, we designed a quantitative method to study NK cell function using imaging flow cytometry (IFC), which combines multiparametric flow cytometry and fluorescence microscopy. Specifically, we developed IFC as a tool to measure polarization and secretion of lytic granules at the immunological synapse formed between an NK cell and a susceptible target. We have further validated our approach through quantitative comparison with high-resolution confocal microscopy. We show that IFC can be used as a quantitative, high throughput measure of NK cell biological function possessing greater dimensionality than standard flow cytometry.

Intratumoral nanofluidic system enhanced tumor biodistribution of PD-L1 antibody in triple-negative breast cancer.

Immune checkpoint inhibitors (ICI), pembrolizumab and atezolizumab, were recently approved for treatment-refractory triple-negative breast cancer (TNBC), where those with Programmed death-ligand 1 (PD-L1) positive early-stage disease had improved responses. ICIs are administered systemically in the clinic, however, reaching effective therapeutic dosing is challenging due to severe off-tumor toxicities. As such, intratumoral (IT) injection is increasingly investigated as an alternative delivery approach. However, repeated administration, which sometimes is invasive, is required due to rapid drug clearance from the tumor caused by increased interstitial fluid pressure. To minimize off-target drug biodistribution, we developed the nanofluidic drug-eluting seed (NDES) platform for sustained intratumoral release of therapeutic via molecular diffusion. Here we compared drug biodistribution between the NDES, intraperitoneal (IP) and intratumoral (IT) injection using fluorescently labeled PD-L1 monoclonal antibody (αPD-L1). We used two syngeneic TNBC murine models, EMT6 and 4T1, that differ in PD-L1 expression, immunogenicity, and transport phenotype. We investigated on-target (tumor) and off-target distribution using different treatment approaches. As radiotherapy is increasingly used in combination with immunotherapy, we sought to investigate its effect on αPD-L1 tumor accumulation and systemic distribution. The NDES-treated cohort displayed sustained levels of αPD-L1 in the tumor over the study period of 14 days with significantly lower off-target organ distribution, compared to the IP or IT injection. However, we observed differences in the biodistribution of αPD-L1 across tumor models and with radiation pretreatment. Thus, we sought to extensively characterize the tumor properties via histological analysis, diffusion evaluation and nanoparticles contrast-enhanced CT. Overall, we demonstrate that ICI delivery via NDES is an effective method for sustained on-target tumor delivery across tumor models and combination treatments.

Potentiating Antitumor Efficacy Through Radiation and Sustained Intratumoral Delivery of Anti-CD40 and Anti-PDL1.

PURPOSE: Mounting evidence demonstrates that combining radiation therapy (RT) with immunotherapy can reduce tumor burden in a subset of patients. However, conventional systemic delivery of immunotherapeutics is often associated with significant adverse effects, which force treatment cessation. The aim of this study was to investigate a minimally invasive therapeutics delivery approach to improve clinical response while attenuating toxicity. METHODS AND MATERIALS: We used a nanofluidic drug-eluting seed (NDES) for sustained intratumoral delivery of combinational antibodies CD40 and PDL1. To enhance immune and tumor response, we combined the NDES intratumoral platform with RT to treat the 4T1 murine model of advanced triple negative breast cancer. We compared the efficacy of NDES against intraperitoneal administration, which mimics conventional systemic treatment. Tumor growth was recorded, and local and systemic immune responses were assessed via imaging mass cytometry and flow cytometry. Livers and lungs were histologically analyzed for evaluation of toxicity and metastasis, respectively. RESULTS: The combination of RT and sustained intratumoral immunotherapy delivery of CD40 and PDL1 via NDES (NDES CD40/PDL1) showed an increase in both local and systemic immune response. In combination with RT, NDES CD40/PDL1 achieved significant tumor burden reduction and liver inflammation mitigation compared with systemic treatment. Importantly, our treatment strategy boosted the abscopal effect toward attenuating lung metastatic burden. CONCLUSIONS: Overall, our study demonstrated superior efficacy of combination treatment with RT and sustained intratumoral immunotherapy via NDES, offering promise for improving therapeutic index and clinical response.

NK cells converge lytic granules to promote cytotoxicity and prevent bystander killing.

Natural killer (NK) cell activation triggers sequential cellular events leading to destruction of diseased cells. We previously identified lytic granule convergence, a dynein- and integrin signal-dependent movement of lysosome-related organelles to the microtubule-organizing center, as an early step in the cell biological process underlying NK cell cytotoxicity. Why lytic granules converge during NK cell cytotoxicity, however, remains unclear. We experimentally controlled the availability of human ligands to regulate NK cell signaling and promote granule convergence with either directed or nondirected degranulation. By the use of acoustic trap microscopy, we generated specific effector-target cell arrangements to define the impact of the two modes of degranulation. NK cells with converged granules had greater targeted and less nonspecific "bystander" killing. Additionally, NK cells in which dynein was inhibited or integrin blocked under physiological conditions demonstrated increased nondirected degranulation and bystander killing. Thus, NK cells converge lytic granules and thereby improve the efficiency of targeted killing and prevent collateral damage to neighboring healthy cells.