Silencing β3 Integrin by Targeted ECO/siRNA Nanoparticles Inhibits EMT and Metastasis of Triple-Negative Breast Cancer

Abstract

Metastatic breast cancer is the second leading cause of cancer-related deaths amongst women. Triple-negative breast cancer (TNBC) is a highly aggressive subcategory of breast cancer and currently lacks well-defined molecular targets for effective targeted therapies. Disease relapse, metastasis, and drug resistance render standard chemotherapy ineffective in the treatment of TNBC. Since previous studies coupled β3 integrin to epithelial-mesenchymal transition (EMT) and metastasis, we exploited β3 integrin as a therapeutic target to treat TNBC by delivering β3 integrin siRNA via lipid ECO-based nanoparticles (ECO/siβ3). Treatment of TNBC cells with ECO/siβ3 was sufficient to effectively silence β3 integrin expression, attenuate TGF-β-mediated EMT and invasion, restore TGF-β-mediated cytostasis, and inhibit 3-dimensional organoid growth. Modification of ECO/siβ3 nanoparticles with an RGD peptide via a PEG spacer enhanced siRNA uptake by post-EMT cells. Intravenous injections of RGD-targeted ECO/siβ3 nanoparticles in vivo alleviated primary tumor burden, and more importantly, significantly inhibited metastasis. Mice bearing orthotopic, TGF-β-pre-stimulated MDA-MB-231 tumors that were treated with RGD-targeted ECO/siβ3 nanoparticles were free of metastases and relapse after primary tumor resection and 4 weeks after release from the treatment, in comparison to untreated mice. Collectively, these results highlight ECO/siβ3 nanoparticles as a promising therapeutic regimen to combat TNBC.

HMGA2–FOXL2 Axis Regulates Metastases and Epithelial-to-Mesenchymal Transition of Chemoresistant Gastric Cancer

“…Several integrin subunits have been reported to participate in EMT, mainly serving as the terminal executor of the EMT process. For example, silencing integrin b3 inhibits the EMT and metastasis of triple-negative breast cancer (40). Integrin a5 has been reported to be a target of ZEB2 and promotes metastasis during EMT (41).…”

FAM83 proteins: Fostering new interactions to drive oncogenic signaling and therapeutic resistance

“…Recent developments in cationic-lipid-based siRNA carriers have been described to efficiently deliver the siRNA cargo intracellularly. When coupled to a targeting peptide such as Arg-Gly-Asp (RGD), which is recognized by β3 integrin in the tumor vasculature, nanoparticles can efficiently target the delivery of siRNA to the tumor [110]. Such particles can now be injected systemically in vivo , with little immunogenicity, no changes in body weight, and no issues with clotting [110].…”

“…When coupled to a targeting peptide such as Arg-Gly-Asp (RGD), which is recognized by β3 integrin in the tumor vasculature, nanoparticles can efficiently target the delivery of siRNA to the tumor [110]. Such particles can now be injected systemically in vivo , with little immunogenicity, no changes in body weight, and no issues with clotting [110]. The rapid and continuing advancements in RNAi strategies will make the targeting of FAM83 members a more feasible option in the near term.…”

Current Challenges toward In Vitro Cellular Validation of Inorganic Nanoparticles

“…In this context, Astashkina et al studied the cytotoxicity and cytokine production of gold and polymeric NPs in a 3D kidney organoid, observing that only the organic NPs were able to penetrate the organoid and produce indicators of toxicity. 103 While we are convinced that this exciting and emerging research field will raise the number of studies assessing inorganic NP–cell interactions and NP therapeutic efficiency, 104 a lack of standards and “teething” issues such as the lack of nutrients and oxygen at the center of the organoid, resulting in cellular necrosis, limits current use for NP validation. 105 …”