Silver nanoparticle functionalized by glutamine and conjugated with thiosemicarbazide induces apoptosis in colon cancer cell line

The high mortality rate of colon cancer indicates the insufficient efficacy of current chemotherapy. Thus, the discussion on engineered metal nanoparticles in the treatment of the disease has been considered. In this study, silver nanoparticles were functionalized with glutamine and conjugated with thiosemiccarbazide. Then, anticancer mechanism of Ag@Gln-TSC NPs in a colon cancer cell line (SW480) was investigated. Characterizing Ag@Gln-TSC NPs by FT-IR, XRD, EDS-mapping, DLS, zeta potential, and SEM and TEM microscopy revealed that the Ag@Gln-TSC NPs were correctly synthesized, the particles were spherical, with surface charge of - 27.3 mV, high thermal stability and low agglomeration level. Using MTT assay we found that Ag@Gln-TSC NPs were significantly more toxic for colon cancer cells than normal fibroblast cells with IC₅₀ of 88 and 186 µg/mL, respectively. Flow cytometry analysis showed that treating colon cancer cells with Ag@Gln-TSC NPs leads to a considerable increase in the frequency of apoptotic cells (85.9% of the cells) and increased cell cycle arrest at the S phase. Also, several apoptotic features, including hyperactivity of caspase-3 (5.15 folds), increased expression of CASP8 gene (3.8 folds), and apoptotic nuclear alterations were noticed in the nanoparticle treated cells. Furthermore, treating colon cancer cells with Ag@Gln-TSC NPs caused significant down-regulation of the HULC Lnc-RNA and PPFIA4 oncogene by 0.3 and 0.6 folds, respectively. Overall, this work showed that Ag@Gln-TSC NPs can effectively inhibit colon cancer cells through the activation of apoptotic pathways, a feature that can be considered more in studies in the field of colon cancer treatment.