RNA interference and the therapeutic applications using small interfering RNA was discovered more than 10 years ago and currently is used in various applications including in therapeutic field. However the research in this field is still in its infancy. Many challenges like safe delivery of targeted siRNA to nucleus and cytosol of cancerous cells without compromising the activity of siRNA needs to be addressed. We have overcome this hurdle with the help of nanotechnology using PLGA hollow nanoparticles (PLGAHNPs) and suppressing the oncogene of MYC transcription factors by using anti myc-siRNAs in human cancer cell lines. siRNA was encapsulated in PLGAHNPs. These spherical PLGAHNPs of size 70 nm had high efficiency of gene release at pH 4.2 under in vitro conditions. Cell penetrating peptide (CPP)- Tat peptide (TAT) and peptide nucleic acidnucleolus localizing signal (PNA-NLS) was used for siRNA delivery without affecting the therapeutic activity of siRNA. The siRNA duplex was prepared using T7 polymerase and double stranded DNA through in vitro transcription. Incubation of the siRNA encapsulated PLGAHNPs functionalized with TAT and PNA-NLS (TAT-siRNA-PNA-PLGAHNPs-siRNA) with cancer cells resulted in reduced cell proliferation. A downregulation of gene expression by 90% was observed even with low concentration of siRNA. We found complete arrest of cell division which was mediated by downregulation of MYC expression.

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