Enhanced Anticancer Activity of Nanoformulation of Dasatinib against Triple-Negative Breast Cancer

Abstract

Triple negative breast cancer (TNBC) is the most aggressive breast cancer accounting for around 15% of identified breast cancer cases. TNBC lacks human epidermal growth factor receptor 2 (HER2) amplification, is hormone independent estrogen (ER) and progesterone receptors (PR) negative, and is not reactive to current targeted therapies. Existing treatment relies on chemotherapeutic treatment, but in spite of an initial response to chemotherapy, the inception of resistance and relapse is unfortunately common. Dasatinib is an approved second-generation inhibitor of multiple tyrosine kinases, and literature data strongly support its use in the management of TNBC. However, dasatinib binds to plasma proteins and undergoes extensive metabolism through oxidation and conjugation. To protect dasatinib from fast pharmacokinetic degradation and to prolong its activity, it was encapsulated on poly(styrene-co-maleic acid) (SMA) micelles. The obtained SMA-dasatinib nanoparticles (NPs) were evaluated for their physicochemical properties, in vitro antiproliferative activity in different TNBC cell lines, and in vivo anticancer activity in a syngeneic model of breast cancer. Obtained results showed that SMA-dasatinib is more potent against 4T1 TNBC tumor growth in vivo compared to free drug. This enhanced effect was ascribed to the encapsulation of the drug protecting it from a rapid metabolism. Our finding highlights the often-overlooked value of nanoformulations in protecting its cargo from degradation. Overall, results may provide an alternative therapeutic strategy for TNBC management.

Keywords: EPR; TNBC; dasatinib; metabolism; nanoformulation; nanomedicine; poly(styrene-co-maleic acid) micelles; targeted therapy.

Figure 1

(a) Chemical structure of dasatinib; (b) SMA–dasatinib drug release studies. Cumulative release of the free drug from SMA–dasatinib micelles at pH 7.4 in PBS and FBS.

Figure 2

Cytotoxicity of dasatinib and SMA–dasatinib (A) against MCF-7, (B) MDA-MB-231, (C) and 4T1 cells. The cells were treated for 72 h with specific concentrations of dasatinib and SMA–dasatinib micelles. The cell number was determined using the SRB assay. Data are expressed as mean ± SEM (n = 3).

Figure 3

In vivo antitumor activity of dasatinib and SMA–dasatinib on 4T1tumor bearing Balb/c mice. Mice were treated for 10 days with single dose of either dasatinib 5 mg/kg and SMA–dasatinib 5 mg/kg. Control group was injected with PBS (pH 7.4). Tumor volume changes (A) and body weight changes (B) were monitored over the treatment period. Data are presented as the mean of triplicate experiments ± standard error.

Figure 4

(A) Tissue and (B) tumor distribution of free dasatinib and SMA–dasatinib at 24 h after intravenous injection of dasatinib or SMA–dasatinib (50 mg/kg) to Balb/c mice bearing 4T1 tumors (n = 5). Representation of the relative content of dasatinib per 100 mg tissue expressed in free and micellar dasatinib.

Figure 5

Cytotoxicity of dasatinib and SMA–dasatinib (A) against HepG2 cells, (B) 4T1 cells after treatment with HepG2. The cells were treated for 48 h with specific concentrations of dasatinib and SMA–dasatinib micelles. The cell number was determined using the SRB assay. Data are expressed as mean ± SEM (n = 8).