Combinatorial suppression of IL-6 and CD73 in cancer cells by siRNA loaded nanoparticles

Abstract

There are many factors present in the tumor microenvironment that their increased expression plays a very important role in the spread of cancer. Increased expression of adenosine and IL-6 in the tumor microenvironment leads to rapid proliferation of cancer cells and inhibition of antitumor immune responses. One of the effective ways of immunotherapy is the combined inhibition of tumor-promoting factors. Therefore, in this study, we decided to suppress the expression of CD73 (the main factor that produces adenosine) and IL-6 in cancer cells. For this purpose, nanoparticles loaded with siRNA were used. Materials and Methods: In this study, alginate conjugated trimethyl chitosan nanoparticles were used to transfer siRNA to cancer cells. The anti-cancer effects of the above compound were evaluated on three cancer cell lines: 4T1 (breast cancer), B16 (melanoma), and CT26 (colorectal cancer). The physicochemical properties of the synthesized nanoparticles were determined using a DLS device. Also, siRNA loading strength and nanoparticle stability were studied using gel electrophoresis. Expression of target genes was also performed using Real-time PCR technique. In addition, the toxicity of the produced nanoparticles was investigated by MTT method. Results: The results of the study showed that the nanoparticles had a size of about ~ 110 nm, PDI <0.2 and a zeta potential of 18 mV. Electron microscopy showed that the nanocomplexes had a spherical morphology and a high capacity for siRNA loading. In addition, the nanoparticles had high stability in serum. Confocal microscopic examination showed that cancer cells significantly absorbed nanoparticles, which suppressed the expression of target genes. Also, combination therapy showed that although nanoparticles alone are not very toxic to cancer cells, combination therapy can significantly reduce cancer cell survival.