Multifunctional hybrid hydrogel for the prevention of post-surgery tumor recurrence

Abstract

In this study, we present a multifunctional hybrid hydrogel (MFHH) for the prevention of postoperative tumor recurrence. MFHH consists of two components; component A - containing a gelatin-based cisplatin, which destroys the residual cancer after surgery, and component B - containing macroporous gelatin microcarriers (CultiSpher) loaded with freeze-dried bone marrow stem cells (BMSCs), which activates the wound healing process. We also evaluated the effects of MFHH in a subcutaneous Ehrlich tumor mouse model. MFHH acted as a local delivery system by directly supplying cisplatin to the tumor environment, resulting in excellent anti-cancer effects and minimal side effects. MFHH released cisplatin gradually to destroy the residual tumors, thereby preventing loco-regional recurrence. We have also demonstrated that BMSCs are able to inhibit residual tumor growth. Moreover, CultiSpher loaded with BMSCs acted as an injection 3D scaffold and easily filled the wound defect formed by tumor removal, and the paracrine factors of the freeze-dried BMSCs accelerated the wound healing process. The components of the MFHH can be used both separately and together. However, for the successful application of MFHH in clinical practice, it is necessary to study in more detail the role of paracrine factors of freeze-dried BMSCs in the inhibition or proliferation of residual cancer. These questions will be the focus of our future research.

Keywords: Ehrlich solid tumor; Multifunctional hybrid hydrogel; bone marrow stem cells; cisplatin mechanism of action; local drug delivery systems; macroporous gelatin microcarriers (CultiSpher).

Figure 1

In vitro degradation profiles of MFHH.

Figure 2

Tumor growth rate in all groups of animals.

Figure 3

Histopathological response to treatment according to the Evans classification scheme. Degree I (<10%) of destruction of cancer cells or its complete absence; IIa degree, destruction of 10-50% of cancer cells; IIb degree, destruction of 51-90% of cancer cells; Grade III, few (<10%) viable cancer cells are present; Grade IV, viable cancer cells are completely absent. (TM) - tumor model, (TR) - resection of 90% of the tumor, (MFHH) - multifunctional hybrid hydrogel, (GHC) - gelatin hydrogels incorporating cisplatin, (CS-BMSCs) - CultiSpher loaded with BMSCs.

Figure 4

Ehrlich subcutaneous tumor model before and after the treatment with gelatin hydrogels incorporating cisplatin (GHC). A. Ehrlich subcutaneous tumor model. Observation period is 20 days; B. Gross section of subcutaneous Ehrlich tumor; C, D. Structural heterogeneity of the tumor, where viable areas are interspersed with necrotic zones. The well-defined tumor capsule, mainly composed by connective tissue. H&E staining, X200, 400; E. The animals of group VI with a tumor model without treatment. Observation period is 20 days; F, G. Anaplastic cells with anarchic progression, and invasion of tumor cells into muscle tissue. H&E staining, X400; H. Staining for DAPI revealed enhanced luminescence in the nuclei of tumor cells. X200; I. The wound suture failure. Observation period is 5 days; J. Layers of tumor cells with necrotic and hemorrhagic areas. H&E staining, X400; K, L. Immunohistochemical studies revealed a high level of expression of Ki-67 and BCL-2 markers; M. In most GHC-treated animals, the wound healed without complications. Observation period is 45 days; N. Destruction of 50% of cancer cells after GHC treatment. H&E staining, X400. Observation period is 30 days; O. Immunohistochemical studies revealed a low level of expression of Ki-67 markers; P. Staining for DAPI revealed a slight increase in luminescence in the nuclei of tumor cells. X200.

Figure 5

Subcutaneous Ehrlich tumor after MFHH and BMSCs treatment. A. Residual tumor after the removal of 90% of the tumor mass; B. The wound is covered with MFHH; C. Scanning electron microscopy confirmed the diffuse distribution of CultiSpher in the wound; D. Staining for DAPI revealed no luminescence. X200; E, F. The platinum nanoparticles are evenly distributed both on the surface of the MFHH and inside the tumor cells; G. Cancer cells destruction after MFHH treatment. H&E staining, X400. Observation period is 30 days; H. Immunohistochemical studies revealed a low level of expression of Ki-67 markers. X200; I. MFHH contains 40 wt% of platinum nanoparticles in different spectra; J. The wound healed without complications after MFHH treatment. H&E staining, X200. Observation period is 30 days; K. The process of resorption of Cultispheres. H&E staining, X800. Observation period is 40 days; L. Collagen fibers around CultiSpheres. Masson’s trichrome stain, X800; M. Connective tissue with new vessels around the CultiSpher. H&E staining, X800; N. After the injection of Cultispheres loaded with BMSCs into the wound, >50% of the cancer cells were destroyed. H&E staining, X800. Observation period is 30 days; O. After iv injection of BMSCs, <50% of the cancer cells were destroyed. H&E staining, X800. Observation period is 30 days; P, Q. Staining for DAPI showed weak luminescence of tumor cell nuclei. X200; R, S. Immunohistochemical studies revealed a low level of expression of Ki-67 and BCL-2 markers. X200.