Evaluation of cytotoxicity of a purified venom protein from Naja kaouthia (NKCT1) using gold nanoparticles for targeted delivery to cancer cell

- Gold nanoparticle has been conjugated with NKCT1 and AuS bond was confirmed.
- GNP-NKCT1 increased the apoptosis, arrested cell cycle and restored the hepatic enzyme.
- Anticancer activity was increased by GNP-NKCT1 as compared with NKCT1.
- Toxicity of NKCT1 towards healthy fibroblast cell was reduced due to GNP conjugation.

In our earlier report, gold nanoparticle (GNP) and snake venom protein toxin NKCT1 were conjugated and primary characteristics were done. In this communication, further characteristics of GNP-NKCT1 were done with TGA, BET, Zeta potential, ICP-MS, FTIR, XPS, and in vitro release kinetics for its physicochemical, molecular nature and bonding. TGA and ICP-MS showed that the number of conjugation was 40 ± 5 to 90 ± 8 NKCT1 per gold nanoparticles. FTIR and XPS corresponding to (CO), (NH), (SS) reformulated the conjugation of GNP with NKCT1. The efficacy of GNP-NKCT1 on cancer cells were analyzed by MTT assay which demonstrated superior cytotoxic effects as compared to native NKCT1. IC50 dose of GNP-NKCT1 was less than 4 μg/ml in cancer cell lines, whereas in case of NKCT1 it was average 8 μg/ml. Twice dose of IC50 of GNP-NKCT1 even showed less toxicity compared to unconjugated NKCT1, towards normal epithelial or fibroblast cell and also in peripheral blood mononuclear lymphocytes. Flow cytometry analysis revealed that percentage of apoptotic C6 cells was much higher in GNP-NKCT1 treatment (54.58%) than that of NKCT1 treatment (26.79%). Flow cytometric analysis of cell cycle using GNP-NKCT1 on C6 cancer cells revealed that it arrested the cell cycle at Go/G1 phases. In diethylnitrosamine (DEN) induced in vivo hepatocarcinoma mice, the activities of hepatic enzymes- aspartate transaminase (AST) and alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and activities of antioxidant enzymes- superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione peroxidase (GPx) were restored by GNP-NKCT1. This study indicated the capability of gold nanoparticles in enhancing the cancer cell uptake of NKCT1 and also suggested that GNP-NKCT1 might be a good source of anti-carcinoma or anti-sarcoma targeted agent.

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