Platelet Membrane-Coated Poly (Lactic-Co-Glycolic Acid) Nanoparticles as a Targeting Drug Delivery System for Multidrug-Resistant Breast Cancer

Abstract

Introduction: Paclitaxel (PTX), widely used chemotherapeutic agent, is limited by poor solubility, P-glycoprotein (P-gp) mediated efflux, and non-specific toxicity. To overcome these challenges, we developed a triple-functionalized nanocarrier system incorporating poly(lactide-co-glycolide) (PLGA)-based nanoparticles (PNs), D-α-tocopheryl polyethylene glycol succinate (TPGS) for P-gp inhibition, and platelet membrane (PM) coating for targeted tumor delivery.

Methods: The PM-coated TPGS-modified PNs with PTX (PTPNs) was characterized by particle size analysis, transmission electron microscopy (TEM), and protein assay to confirm PM coating. In vitro drug release studies were conducted under acidic conditions mimicking the tumor microenvironment. Cellular assays were performed to evaluate cytotoxicity and drug efficacy in multidrug-resistant MCF-7/ADR cells. In vivo biodistribution and xenograft studies assessed tumor accumulation and therapeutic outcomes.

Results: PTPNs exhibited a particle size of 221 ± 2 nm with a PDI of 0.090 ± 0.020 and a zeta potential of -30.5 ± 0.3 mV, indicating a homogeneous particle distribution and successful PM coating. The optimal PM-to-PLGA weight ratio was determined to be 0.005, which ensured structural stability and uniform coating in physiological conditions. Sustained PTX release was observed in acidic conditions, mimicking the tumor microenvironment. Cellular assays showed a 17-fold reduction in PTX IC₅₀ in MCF-7/ADR cells compared to free PTX, attributed to the synergistic effects of TPGS-mediated P-gp inhibition and PM-based tumor targeting. In vivo, PTPNs demonstrated enhanced tumor accumulation and significantly reduced tumor burden, with final tumor volume 2.6-fold lower than that of TPNs and 3.6-fold lower than that of the PTX commercial product (Taxol^®)-treated group. Tumor necrosis factor-α (TNF-α) levels were also reduced, reflecting decreased tumor-promoting cytokine activity.

Conclusion: The PTPNs enhanced PTX delivery by improving tumor specificity, overcoming multidrug resistance, and reducing systemic toxicity. These results suggested the potential of this biomimetic approach to advance cancer therapy.

Keywords: Poly(lactide-co-glycolide); cancer therapy; multidrug resistance; nanoparticles; paclitaxel; platelet membrane.

Figure 1

PM-coated TPGS-modified PLGA nanoparticles loaded with PTX (PTPN) designed for the treatment of multidrug-resistant breast cancer. The mechanism involves selective targeting of tumor cells via P-selectin on the PM binding to CD44 receptors overexpressed on cancer cells. Following receptor-mediated endocytosis, the nanoparticles escape the endo-lysosomal pathway and release PTX in the acidic tumor microenvironment, stabilizing microtubules and inducing apoptosis.

Figure 2

(a) SEM image of TPNs. (b) TEM image of TPNs. (c) Particle size change of PTPNs coated with varying PM to PLGA ratios (w/w) measured after dispersed in deionized water, after adjusting to PBS buffer solution, and after adjusting to plasma (n = 3). (d–g) TEM images of PTPNs at varying PM/ PLGA ratio (w/w): (d) 0 (control; TPNs); (e), 0.0025; (f), 0.005; (g) PM. The top is an image at low magnification, and the bottom is an image at high magnification.

Figure 3

Characterization of PTPNs. (a) Particle size and zeta potential of TPNs, PTPNs, and PM (n = 3). (b) protein contents of PM, TPNs, and bovine serum albumin (BSA) visualized on a Coomassie blue stained SDS-PAGE gel. (c) Western blot analysis presenting CD41 protein bands in PM and PTPNs. BSA was used as a negative control. (d) TEM images of optimized PTPNs negatively stained with uranyl acetate. Left image: scale bar = 200 nm; right image: scale bar = 100 nm. (e) In vitro release profiles of PTX from TPNs and PTPNs: A, the cumulative released% of PTX from TPNs and PTPNs for 96 h in pH 4.5, 6.8, 7.4 buffer with 2% SDS (n = 3). p values: *p < 0.05, ****p < 0.0001.

Figure 4

Cytotoxicity of B-TPNs, B-PTPNs, TPNs, and PTPNs compared to free PTX. Cell viability assays were conducted against MCF-7 cells for (a) 24 h and (b) 48 h, and against MCF-7/ADR cells for (c) 24 h and (d) 48 h (n = 5).

Figure 5

Cellular uptake of free C6, C6-TPNs, and C6-PTPNs in MCF-7 and MCF-7/ADR cells analyzed by flow cytometry at (a) 2 h, (b) 6 h, and (c) 24 h (n = 3). p values: *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001.

Figure 6

In vivo and ex vivo imaging of free Cy5.5, Cy5.5-TPNs, and Cy5.5-PTPNs in nude mice bearing MCF-7/ADR tumors. (a) Fluorescence images captured at various time points up to 24 following intravenous injection (n = 3). Red dashed line indicates the xenografted tumor tissue in mice. (b) Ex vivo fluorescence images of tumors and major organs 24 h post-injection. (c) Quantitative analysis of fluorescence intensities in tumors and major organs (n = 3). p values: *p < 0.05.

Figure 7

In vivo antitumor efficacy of control (PBS), PTX commercial product (Taxol^®), TPNs, and PTPNs in nude mice bearing MCF-7/ADR tumors. (a) Tumor growth curves according to volume changes over 14 days, with formulations administered intravenously every 3 days (red dashed lines indicate injection time points) (n =5). (b) Body weight changes of mice in each experimental group during the treatment period (n =5). (c) Representative images of tumors excised from mice after 14 days of treatment. (d) Average tumor weights recorded from the excised tumors after 14 days of treatment (n =5). (e) TNF-α levels in serum after 14 days of treatment (n = 5). p values: *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 (mean ± SD; n = 5).