ABSTRACT
The purpose of this study was to fabricate biostable inorganic silver nanoparticles (AgNPs) using fresh peel (aqueous) extract of Benincasa hispida. A fast, robust, and eco-friendly approach was used for the synthesis of AgNPs, where bioactive components of peel extract of B. hispida acted as reducing and stabilizing agents. Synthesized AgNPs were characterized using a UV-Vis spectrophotometer, Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and electron microscopy. The synthesized nanoparticles exhibited maximum absorption at 418 nm under the typical AgNPs surface plasmon resonance band range. They depicted a mean size of 26 ± 2 nm with a spherical shape. Their therapeutic prospective was determined by evaluating their antimicrobial and anticancer potential. The bio-synthesized silver nanoparticles exhibited strong antimicrobial activity with minimum inhibitory concentration (MIC 50) values of 14.5, 8.6, 6.063, and 13.4 µg/mL against Staphylococcus aureus (ATCC 25923), Micrococcus luteus (ATCC 14593), Escherichia coli (ATCC 25922), and Klebsiella pneumonia (ATCC 13883), respectively. The biosynthesized AgNPs showed potent in vitro cytotoxicity against human cervical cancer cell line with a half maximal inhibitory concentration (IC50) value of 0.066 µg/mL; however, no cytotoxic effect was observed on normal human primary osteoblasts cell line. This study explored B. hispida extract and confirmed its effectiveness as a promising source in producing AgNPs that could be employed for several therapeutic applications.
ABSTRACT
Background and purpose:Loss or altered expression of Ras association domain family 1A gene (RASSF1A) through DNA methylation has been associated with the pathogenesis of a variety of cancers, which suggests the tumor suppressor function of this gene. This study aimed to explore the effect of DNA methyltransferase inhibitor 5-Aza-2’deoxycytidine (5-Aza-dc) on demethylation and expression of RASSF1A in cervical cancer cell lines. Methods:HPV positive cervical cancer cell lines HeLa and Caski, HPV negative cell lines HT-3 and C-33A were treated with two different concentration of 5-Aza-dc (5 μmol/L, 10 μmol/L). MSP (methylation-specific PCR) and Bisulfite genomic sequencing PCR (BGS) combined with TA clone were used to investigate methylation status of RASSF1A gene promoter and exon 1 before and after treatment of 5-Aza-dc. RASSF1A gene mRNA expression was detected by RT-PCR. Results:Two HPV positive cell lines showed hypomethylated RASSF1A promoters and expressed RASSF1A mRNA, and after treatment with 5-Aza-dc, the mRNA expression of RASSF1A did not change significantly (FHeLa=3.003, P=0.125; FCaski=0.045, P=0.956). Two HPV negative cervical cancer cell lines showed hypermethylation status of RASSF1A promoter and silenced RASSF1A. After treatment with 5-Aza-dc, demethylation occurred in the promoter region of RASSF1A gene, which subsequently induced re-expression of this gene in HT-3 and C-33A. The F test (FHT-3=18.002, P=0.03;FC-33A=17.179, P=0.03) and LSD-t test (P<0.05) demonstrated that significant difference in the expression of RASSF1A was found upon two different concentrations drug treatment.Conclusion:The methylation status of promoter and exon 1 of RASSFIA gene in HPV positive and HPV negative cervical cancer cell lines are different. The promoter hypermethylation is correlated with RASSF1A gene expression in HPV negative cervical cancer cell line HT-3 and C-33A, and plays a key role in RASSF1A silencing. 5-Aza-dc may effectively reverse the methylation status of RASSFIA gene promoter in cervical cancer HT-3 and C-33A cells and reactivate gene expression silenced by aberrant hypermethylation in a dose-dependent manner within certain extent.
