en Pharmaceutical Biotechnology Pharmaceutical Biotechnology مقاله کامل Full Length/Original Article <span style="font-size:11pt"><span style="line-height:normal"><span calibri="" style="font-family:"><b><span style="font-size:10.5pt"><span style="background:white"><span new="" roman="" style="font-family:" times=""><span style="color:black">Background:</span></span></span></span></b> <span style="font-size:10.5pt"><span new="" roman="" style="font-family:" times="">The E6 oncoprotein of HPV plays a crucial role in promoting cell proliferation and inhibiting apoptosis, leading to tumor growth. Non-viral vectors such as nona-arginine (R9) peptides have shown to be potential as carriers for therapeutic molecules. This study aimed to investigate the efficacy of nona-arginine in delivering E6 shRNA and suppressing the E6 gene of HeLa cells in vitro. </span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span calibri="" style="font-family:"><b><span style="font-size:10.5pt"><span new="" roman="" style="font-family:" times="">Methods:</span></span></b><span style="font-size:10.5pt"><span new="" roman="" style="font-family:" times=""> HeLa cells carrying E6 gene were treated with a complex of nona-arginine and E6 shRNA. The complex was evaluated using gel retardation assay and FESEM microscopy. The optimal N/P ratio for R9 peptide to transfect HeLa cells with luciferase gene was determined.&nbsp; Relative real-time PCR was used to evaluate the efficiency of mRNA suppression efficiency for E6 shRNA, while the effect of E6 shRNA on cell viability was measured using an MTT assay.</span></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span calibri="" style="font-family:"><b><span style="font-size:10.5pt"><span new="" roman="" style="font-family:" times="">Results:</span></span></b><span style="font-size:10.5pt"><span new="" roman="" style="font-family:" times=""> The results indicated that R9 efficiently binds to shRNA and effectively transfects E6 shRNA complexes at N/P ratios greater than 30. Transfection with R9 and polyethylenimine complexes resulted in a significant toxicity compared to the scrambled plasmid, indicating selective toxicity for HeLa cells. Real-time PCR confirmed the reduction of E6 mRNA expression levels in the cells transfected with anti-E6 shRNA.</span></span></span></span></span><br> <b><span style="font-size:10.5pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times="">Conclusion:</span></span></span></b><span style="font-size:10.5pt"><span style="line-height:115%"><span new="" roman="" style="font-family:" times=""> The study suggests that R9 is a promising non-viral gene carrier for transfecting E6 shRNA in vitro, with significant transfection efficiency and minimal toxicity.</span></span></span> Cell-penetrating peptides, E6 oncogene, Human papillomavirus 18, RNA interference 349 356 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-5467-1&slc_lang=en&sid=1 Razieh Taghizadeh Pirposhteh 0000-0003-3760-4230 No Department of Molecular Virology, Pasteur Institute of Iran, Tehran 1316943551, Iran Ehsan Arefian 0000-0002-0758-4710 No Department of Microbiology, School of Biology, College of Science, University of Tehran 1417614411, Iran Arash Arashkia 0000-0002-3117-3217 No Department of Molecular Virology, Pasteur Institute of Iran, Tehran 1316943551, Iran Nasir Mohajel nasirmohajel@gmail.com 0000-0001-8883-4429 Yes Department of Molecular Virology, Pasteur Institute of Iran, Tehran 1316943551, Iran