*3.3.3 NPs for miRs delivery*

Micro RNAs (miRs) are short and non-coding RNAs that modulate gene expression at the level of post-transcriptional. The existence of them is necessary for the regulation of cell metabolism, differentiation, proliferation, and apoptosis. But sometimes, dysregulation and improper expression of miRs (oncomiRs) are related to the early and advanced stages of cancers, so, anti-miR delivery for downregulating oncomiR is an anticancer strategy. A high level of miR-21 is related to the incidence of many cancers including OC. In order to improve cancer therapy porous silicon NPs that were modified by MAL-PEG-SVA enclosed anti-miR-21 (LAN) to target OAW42 ovarian cells. In this study, CREK peptide as a control peptide for no targeting activity in cell culture and CGKRK peptide for displaying tumorhoming and tumor penetrating properties were analyzed for comparison. Findings illustrated a decrease in cell viability due to apoptosis by evaluating caspase-3, and also, COV-318 xenograft tumors subcutaneously transplanted into nude mice after treatment represented the higher accumulation of NPs in tumor tissue that lead to inhibition effect on tumor growth and volume [57].
