SYNTHESIS AND EFFECTS OF A PHOTOACTIVATED SILVER NANOPARTICLE PLATFORM DELIVERING MIR-148B IN LUNG ADENOCARCINOMA

Open Access
Author:
Chan, Alexander
Area of Honors:
Biomedical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Daniel J Hayes, Thesis Supervisor
  • Jian Yang, Honors Advisor
  • Scott H Medina, Faculty Reader
Keywords:
  • cancer
  • lung cancer
  • silver
  • silver nanoparticles
  • nanoparticles
  • theranostics
  • siRNA
  • miRNA
  • photothermal
Abstract:
Of the nearly 600,000 cancer-related deaths in 2016, 158,080 or 26.5% were attributed to lung cancer. As such, lung cancer remains one of the deadliest diseases among men and women. Furthermore, lung cancer continues to be one of the most commonly-diagnosed cancers with 14% new cases among men and 13% new cases among women in 2016. One of the most common forms of lung cancer is adenocarcinoma, an epithelial non small-cell lung cancer (NSCLC). Over 85% of all lung cancers are categorized as NSCLCs, and current treatments modalities are still limited to traditional surgical resection and radiotherapy. Despite advances in both fields, such as minimally-invasive lobe resection and stereotactic body radiation therapy, these techniques are limited to early-stage cancers. Additionally, few treatments rely on signaling inhibition, since few NSCLCs are identified as EGFR or ALK mutant, which would allow for kinase inhibitor therapy. As such, a significant amount of research has been devoted to developing targeted therapies for NSCLC to improve therapeutic outcomes and reduce systemic side effects. In this study, we develop a novel silver nanoparticle/miR-148b construct for treatment of lung adenocarcinoma. We use human A549 cells as an in vitro model to test the miRNA and silver nanoparticle constructs. This system uses miR-148b, a regulatory RNA which has been studied in several cancer types including melanoma and breast cancer and has been shown to negatively affect cancer growth. Additionally, we use a furan-maleimide pair diels-alder adduct to tether miR-148b to particle surfaces. By exploiting the plasmonic properties of nanoscale silver, it is possible to control miR-148b release spatiotemporally for targeted therapeutic delivery. Additionally, plasmonic generation of hot electrons is hypothesized to induce localized thermal ablation of cancer cells for dual-modal therapy. In this study, a novel miRNA silver nanoparticle was synthesized and investigated in lung cancer cell cultures. Particles were characterized using TEM and DLS to determine the size of the final construct to be approximately 76 nm. Surface charge was also measured and upon reaction with negatively-charged miRNA, zeta potentials decreased from -4 mV in the unmodified state to -31 mV in the fully conjugated state. After characterization, the release mechanism was tested using LED activation at 420 nm. Fluorescence of TAMRA-labelled miR-148b after light irradiation indicated successful cleavage of the diels alder adduct, demonstrating the ability to control release of the miRNA. Furthermore, incubation of cells with SNPs followed by irradiation showed a significant (p < 0.05) drop in cell viability, showing promise for light-mediated thermal ablation. However, in testing the in vitro effects of miR-148b via chemical transfection, no significance (F < Fcrit and p > 0.05) in viability was determined in terms of viability after miR-148b treatment. Additionally, between groups, chemosensitivity did not change upon transfection. Taken together, these data indicate a potential spatiotemporally-controllable treatment modality using RNA interference/ thermal ablation technology with controlled release. However, further studies must be performed to elucidate and tailor the miRNA therapeutic agent for this specific model, since this study has not recapitulated some of the therapeutic effects of miR-148b in cancer cells.