Effects of Mangaba (Hancornia speciosa) Fruit Extract Adsorbed onto PEG Microspheres in MCF-7 Breast Cancer Cells Co-Cultured with Blood Cells

Abstract

Objective: To evaluate the antitumor effects of polyethylene glycol (PEG) microspheres with adsorbed Hancornia speciosa ethanolic extract (HSEE) on blood mononuclear (MN) cells co-cultured with MCF-7 breast cancer cells. Methods: PEG microspheres were adsorbed with HSEE and examined by flow cytometry and fluorescence microscopy. MCF-7 and MN cells obtained from volunteer donors were pre-incubated alone or co-cultured (MN and MCF-7 cells) for 24 h with or without HSEE, PEG microspheres or PEG adsorbed with HSEE (PEG-HSEE). Cell viability, superoxide release and superoxide dismutase were determined. Results: Fluorescence microscopy showed that PEG microspheres were able to absorb HSEE throughout their surface. Irrespective of the treatment, the viability index of MN cells, MCF-7 and their co-culture was not affected. Superoxide release increased in co-cultured cells treated with HSEE, adsorbed or not onto PEG microspheres. In co-cultured cells, SOD levels in culture supernatant increased in the treatment with HSEE, adsorbed onto PEG microspheres or not. Conclusion: HSEE has direct effects on MN cells co-cultured with MCF-7 cells. The results suggest the benefits of Hancornia speciosa fruit consumption by women at risk of breast cancer. In addition, because PEG-HSEE maintained oxidative balance in co-cultured cells, it is a promising alternative for the treatment of tumor cells.

Keywords: Antioxidant activity; Biomaterial; Brazilian fruit; Microspheres; cancer.

Figure 1

Fluorescence Microscopy Image of Polyethylene Glycol (PEG) Microspheres Stained with Dylight-488 (100x - panels - A). PEG microsphere (Figure 1A); PEG microsphere adsorbed to 100 ng.mL^-1 H. speciosa ethanolic extract (Figure 1B). Comparable results of 5 replications

Figure 2

PEG Microspheres Stained with Phycoerythrin (PE) and Standard PE-Labeled Polymethyl Methacrylate Microsphere (BD Microsphere, Becton Dickinson, San Jose, USA), with Fluorescence Intensity and Size Determined by Flow Cytometry (FACScalibur, Becton Dickinson, San Jose, USA). Microsphere size according to forward scatter (A); geometric mean of the microsphere adsorbed with 100 ng.mL-1 H. speciosa ethanolic extract (B).

Figure 3

Superoxide Release by Blood MN(A), MCF-7(B) and Co-Cultured MN and MCF-7 Cells (C) Incubated with PBS, PEG, H. speciosa Ethanolic Extract (HSEE) Alone or Adsorbed to PEG Microspheres (HSEE-PEG) after 24-h Culture. Data are expressed as mean ± SD. *difference between the treatments PEG, HSEE and PEG- HSEE for a same cell type (P<0.05); # difference between MCF-7and co-cultured MN and MCF-7 cells within a same treatment (P <0.05)