Hamidreza Maroof, Vinod Gopalan, LanFeng Dong, Alfred KY Lam *.


School of Medicine Griffith University, Gold Coast, QLD, Australia


Background: Initiation and progression of thyroid cancer involves multiple genetic and epigenetic alterations, of which mutations leading to activation of the VEGF-A signalling pathways is crucial. This study aimed to inhibit the VEGF-A pathway by overexpression of miR-34b-5p using a PEGylated miRNA-loaded lipid particles system and investigates its cellular implications. Materials and methods: Two human undifferentiated thyroid carcinoma cell lines (8505C and BHT-101) and a non-neoplastic thyroid follicular (Nthy-ori 3-1) cell lines were used in this study. Hydration of a freeze-dried matrix (HFDM) formulated liposomes (PEGlylated-miR-34b-5p) was used for the systemic delivery in vitro. Real time-PCR, western blot and various In vitro functional assays were performed to confirm the miR-34b-5p induced changes in thyroid cancer cell biology and VEGF-A protein.  Results: miR-34b-5p expression was low and significantly (P<0.05) overexpressed following transfection with PEGlylated-miR-34b-5p in thyroid cancer cell lines. VEGF-A protein was remarkably reduced in transfected cell line when compared to controls (P<0.05). Approximately, 64% proliferation inhibition (p < 0.05) was observed following miR-34b-5p overexpression compared to control cells. Cell cycle assay revealed approximately 22.68% ± 2.33 and 10.41% ± 1.55 arrest in 8505C and BHT-101 respectively (P<0.05). The early and late apoptosis rates of these cell lines transfected with miR-34b-5p were significantly increased(P<0.05).  The created wound, healed faster in PEGlylated-miR-1 and non-transfected control whereas wound in transfected cell lines healed slightly. Furthermore, miR-34b-5p overexpression significantly (P<0.05) reduced VEGF-A secretion in cancer cells media. Conclusions: This study indicated that miR-34b-5p could modulate of angiogenesis in thyroid cancer cells and delivery of miR-34b-5p using a cationic liposome may provide an effective therapeutic delivery strategy for thyroid cancer treatment.