Expression of key apoptotic genes in hepatocellular carcinoma cell line treated with etoposide-loaded graphene oxide

Abstract Etoposide (Et) is an antineoplastic agent used for cancer treatment as it promotes the apoptosis of cancer cells. One of the important concerns about Et is the poor water solubility and bioavailability which lowers its cytotoxicity for pharmaceutical applications. Here, Et was loaded on a new carrier, made of carboxylated graphene oxide (GO-COOH), to improve the cytotoxicity of Et on hepatocellular carcinoma (Hep-G2) cells without any destruction on the apoptosis pathway of Et. SEM, TEM, UV–Vis, FT-IR, DLS and Raman were utilized as the characterization techniques. The cytotoxicity of Et on Hep-G2 cells was probed by MTT before and after loading on GO-COOH as well as the flow cytometry. Real-time PCR was used to find the expression of apoptotic genes in Hep-G2 cells treated with free Et and Et-loaded GO-COOH (Et-GO-COOH). From MTT results, IC50s of Et and Et-GO-COOH were measured as 6 ± 1.73 and 4 ± 0.11 μg/mL, respectively. Real-time PCR results revealed that both Et-GO-COOH and Et caused toxicity through induction of the expression of same seven apoptotic genes. However, Et-GO-COOH acted more efficiently than Et to induce apoptosis in Hep-G2 cells. The findings verified that GO-COOH improved the cytotoxicity effect of Et with no impact on the Et apoptosis pathway.