A Modular Composite Device of Poly(Ethylene Oxide)/Poly(Butylene Terephthalate) (PEOT/PBT) Nanofibers and Gelatin as a Dual Drug Delivery System for Local Therapy of Soft Tissue Tumors

Abstract

In the clinical management of solid tumors, the possibility to successfully couple the regeneration of injured tissues with the elimination of residual tumor cells left after surgery could open doors to new therapeutic strategies. In this work, we present a composite hydrogel-electrospun nanofiber scaffold, showing a modular architecture for the delivery of two pharmaceutics with distinct release profiles, that is potentially suitable for local therapy and post-surgical treatment of solid soft tumors. The composite was obtained by coupling gelatin hydrogels to poly(ethylene oxide)/poly(butylene terephthalate) block copolymer nanofibers. Results of the scaffolds' characterization, together with the analysis of gelatin and drug release kinetics, displayed the possibility to modulate the device architecture to control the release kinetics of the drugs, also providing evidence of their activity. In vitro analyses were also performed using a human epithelioid sarcoma cell line. Furthermore, publicly available expression datasets were interrogated. Confocal imaging showcased the nontoxicity of these devices in vitro. ELISA assays confirmed a modulation of IL-10 inflammation-related cytokine supporting the role of this device in tissue repair. In silico analysis confirmed the role of IL-10 in solid tumors including 262 patients affected by sarcoma as a negative prognostic marker for overall survival. In conclusion, the developed modular composite device may provide a key-enabling technology for the treatment of soft tissue sarcoma.

Keywords: PEOT/PBT; chemotherapy; composite scaffold; dual-drug delivery systems; electrospinning; gelatin; hydrogel; regenerative medicine; sarcoma.

Figure 1

Schematic illustration of the final structure and of the procedure for the fabrication of 3070DKMonoGelCTC (A) and 3070DKDoubleGelCTC (B).

Figure 2

Characterization of the PEOT/PBT electrospun fibers. SEM images of the following: (A) 3070, (B) 3070DK, (C) 7030 and (D) 7030DK fibers; scale bar = 10µm. (E) DSC curves (second heating scans) of 3070 (black) and 3070DK (blue) mats. (F) DSC curves (second heating scans) of 7030 (black) and 7030DK (blue) mats. (G) Water contact angle measurements over time for 3070 (black square), 3070DK (green circle) and 7030 (red triangle) mats. (H) DK cumulative release profile over time for 3070DK (green circle) and 7030DK (blue diamond) electrospun fabrics.

Figure 3

Scanning electron microscopy micrographs of mono-layer (A,B) and double-layer (C,D) composites. Scale bar: 100 µm (A,C), 5 µm (B,D).

Figure 4

Gelatin cumulative release from 3070DKMonoGelCTC (yellow), 3070DKDoubleGelCTC (green), 3070MonoGel (black) and 3070DoubleGel (red). Each analysis was carried out in triplicate.

Figure 5

(A) Drugs cumulative releases. DK cumulative release profile over time from fibers (dash-dot line), mono-layer (dotted line), and double-layer composites (continuous line). (B) Comparison between CTC (blue) and DK (red) cumulative release profiles over time from mono-layer (B) and double-layer composite devices (C), respectively.

Figure 6

(A) Viability assay of VA-ES-BJ human epithelioid sarcoma cell line in a transwell culture system (indirect co-culture) with 3070DoubleGel, 3070DKDoubleGel, 3070DoubleGelCTC, and 3070DKDoubleGelCTC. (B) Representative immunofluorescence confocal images of VA-ES-BJ human epithelioid sarcoma cell line cultured in an empty patch at days 1 and 7. Actin filaments were stained with phalloidin (green) and nuclei were counterstained with dapi (blue). Magnification at 20×, scale bar = 200 µm. (C) Fold change in cell proliferation (cell number) day 7 versus day 1 (* p ˂ 0.05). (D) Morphological characterization of VA-ES-BJ human epithelioid sarcoma cell line after exposure to patches in the indirect co-culture. Architectural features of VA-ES-BJ with typical epithelial-appearing (ovoid or polygonal) cells mixed with fusiform cells with many intracytoplasmic vacuoles were maintained with 3070DoubleGel, 3070DKDoubleGel, and 3070DoubleGelCTC while morphological changes such as rounding up were observed with a combination treatment (3070DKDoubleGelCTC). Magnification 20×, scale bar = 200 µm.

Figure 7

(A) IL-10 protein detection by using an ELISA assay in the supernatant of VA-ES-BJ human epithelioid sarcoma cell line in a transwell culture system (indirect co-culture) with3070DoubleGel, 3070DKDoubleGel, 3070DoubleGelCTC, 3070DKDoubleGelCTC, and positive control DK at both the concentration of 3mg mL⁻¹ (human plasma peak) and 100 mg mL⁻¹ (expected cumulative release from the device). (B) In silico analysis of IL-10 mRNA expression among tumors (red bar) and normal tissues (blue bar, reported when available), *: p-value < 0.05; **: p-value <0.01; ***: p-value <0.001. (C) IL-10 mRNA expression among 262 patients affected by sarcoma (red bar) and normal tissues (grey bar). (D) Kaplan–Meier curve of overall survival analysis based on the expression status of IL-10 in multiple cancer types.