Objective: Breast cancer (BC) is the most common malignancy in females globally. Matrix metalloproteinase-9 (MMP-9) is crucial to the invasion, progression and spread of BC. Gold nanoparticles (AuNPs) have an anti-tumorigenic role, but their therapeutic role in microRNAs (miRNAs) regulation has not been explored. This study determined the potential of AuNPs against MMP-9 overexpression/production and miRNA-204-5p regulation in BC cells. Methods: AuNPs were newly engineered, and their stability was analyzed using the zeta potential, polydispersity index, surface-plasmon-resonance peak and transmission electron microscopy. A bioinformatics algorithm was used to predict the pairing of miRNA in the 3′untranslated-region (3′UTR) of MMP-9 mRNA. TaqMan assays were carried out to quantify miRNA and mRNA, whereas MMP-9-specific immunoassays and gelatin zymography were used to determine protein secretion and activity. The binding of miRNA in MMP-9 mRNA 3′UTR was verified by luciferase reporter clone assays and transfection with anti-miRNAs. In addition, NF-κBp65 activity was determined and confirmed with parthenolide treatment. Results: Engineered AuNPs were highly stable and spherical in shape, with a mean size of 28.3 nm. Tested in MCF-7 BC cells, microRNA-204-5p directly regulates MMP-9. AuNPs inhibit PMA-induced MMP-9 mRNA and protein via hsa-miR-204-5p upregulation. Anti-miR-204 transfected MCF-7 cells demonstrated enhanced MMP-9 expression (p < 0.001), while AuNPs treatment attenuated MMP-9 expression in a dose-dependent manner (p < 0.05). Moreover, AuNPs also inhibit PMA-induced NF-κBp65 activation in anti-hsa-miR-204 transfected MCF-7 cells. Conclusion: Engineered AuNPs were stable and non-toxic to BC cells. AuNPs inhibit PMA-induced MMP-9 expression, production and activation via NF-κBp65 deactivation and hsa-miR-204-5p upregulation. These novel therapeutic potentials of AuNPs on stimulated BC cells provide novel suggestions that AuNPs inhibit carcinogenic activity via inverse regulation of microRNAs.

Hepatoblastoma is the most common primary pediatric liver tumor. Children with pulmonary metastases at diagnosis experience survival rates as low as 25%. We have shown PIM kinases play a role in hepatoblastoma tumorigenesis. In this study, we assessed the role of PIM kinases in metastatic hepatoblastoma. We employed the metastatic hepatoblastoma cell line, HLM_2. PIM kinase inhibition was attained using PIM3 siRNA and the pan-PIM inhibitor, AZD1208. Effects of PIM inhibition on proliferation were evaluated via growth curve. Flow cytometry determined changes in cell cycle. AlamarBlue assay assessed effects of PIM kinase inhibition and cisplatin treatment on viability. The lethal dose 50% (LD₅₀) of each drug and combination indices (CI) were calculated and isobolograms constructed to determine synergy. PIM kinase inhibition resulted in decreased HLM_2 proliferation, likely through cell cycle arrest mediated by p21. Combination therapy with AZD1208 and cisplatin resulted in synergy, potentially through downregulation of the ataxia-telangiectasia mutated (ATM) kinase DNA damage response pathway. When assessing the combined effects of pharmacologic PIM kinase inhibition with cisplatin on HLM_2 cells, we found the agents to be synergistic, potentially through inhibition of the ATM pathway. These findings support further exploration of PIM kinase inhibition as a therapeutic strategy for metastatic hepatoblastoma.

Hepatoblastoma is the predominant primary liver malignancy in children, and outcomes remain poor for patients with metastatic disease. Long non-coding RNAs (lncRNAs) regulate tumor behavior, but their role in metastatic hepatoblastoma is not well defined. This study investigates the expression and functional significance of the lncRNA, maternally expressed gene 3 (MEG3), in a metastatic hepatoblastoma model. RNA sequencing comparing the metastatic hepatoblastoma cell line, HLM_2, with its parental HuH6 cell line identified MEG3 as being significantly upregulated in metastatic cells. MEG3 expression was examined using hepatoblastoma patient datasets and validated using qPCR in cell lines, orthotopic tumors, and COA67 patient-derived xenografts. The effects of siRNA MEG3 knockdown in HLM_2 cells on clonogenicity, migration, and invasion were evaluated. The effects of MEG3 overexpression on migration and invasion were assessed in HuH6 cells. MEG3 was significantly upregulated in metastatic cells and orthotopic tumors compared with controls. MEG3 silencing reduced clonogenicity, tumorsphere formation, migration, and invasion. MEG3 overexpression increased migration and invasion. These findings indicate that MEG3 contributes to an aggressive tumor phenotype, highlighting the need for further examination into its mechanistic role in hepatoblastoma and its potential as a biomarker or therapeutic target.