Background Breast cancer represents the most frequent malignancy in women worldwide and suffers from high death rates despite the research and development of cancer medicines as treatment strategies. The failure of the treatment suggests the distant organ metastasis and angiogenesis with poor diagnosis. An innovative approach in cancer nanomedicine based on the exploitation of piezoelectric nanomaterials that can remotely respond to external irradiation could be promising in cancer treatment; however, the role of piezoelectricity on cancer cells remains unclear and further investigations are still required to comprehend the mechanism. Hypothesis Humanized monoclonal antibody (trastuzumab) decorated piezoelectric nanovectors (Tmab-Nylon-11) are ableto preferentially target the breast cancer cells owing to binding of the extracellular domain of human epidermal growth factor receptor 2 (HER2) overexpressed in invasive breast cancer tumors. The targeting and therapeutic approach in breast cancer therapy is accompanied by ultrasound stimulation due to the piezoelectric anomaterials featuring the capability of converting mechanical energy to electricity. This strategy is supposed to improve the therapeutic efficacy in breast cancer metastasis, particularly in inhibition of angiogenesis. Aims The main objectives of this project are i) the targeting of breast cancer cells and ii) the inhibition of tumor angiogenesis and ultimately metastasis using humanized monoclonal antibody decorated piezoelectric nanovectors. Targeting delivery will allow the increasing the concentration of the nanovectors to the target area while avoiding undesirable interaction with the other tissues. The therapeutic efficiency of the prepared nanovectors will be further improved upon ultrasound irradiation, which is non-invasive and remotely controllable. Experimental Design The project will start with preparation and characterization of the antibody decorated piezoelectric nanovectors. After biocompatibility and uptake studies either on HER2-positive human breast cancer and on human mammary microvascular endothelial cells, extensive in vitro experiments will be performed in order to determine the therapeutic efficiency on cancer cells and the anti-angiogenic activity on endothelial cells upon ultrasound stimulation. Biomolecular investigations will be further performed to understand the mechanism underlying angiogenesis. Finally, the nanovectors will be validated in vivo xenograft mouse model. Expected Results Using the prepared antibody decorated nanovectors, the increased accumulation to the tumor area will be achieved owing to specific binding of antibody to the HER2-positive human breast cancer cells. In addition, the antibody therapy will allow to inhibit tumor angiogenesis due to modulating anti-angiogenic factors. This system will be further reinforced by ultrasound stimulation to improve the therapeutic efficacy in breast cancer angiogenesis. Impact On Cancer The prepared nanovector proposes a strategy to target and inhibit the angiogenesis in HER2-positive human breast cancer thanks to a combination of smart targeting and piezoelectric nanomaterials. Obtained results will help to comprehend the mechanism underlying the angiogenesis, leading to envision in clinical studies. Background Breast cancer is the most commonly diagnosed cancer in female patients with 24.5% of all cancers in 2020, and it is estimated that the mortality rate will increase 33.8% until 2040 [1]. It is a heterogeneous disease including breast cancer gene (BRCA) mutations, hormone receptors (oestrogen and progesterone receptor) and activation of human epidermal growth factor receptor 2 (HER2). The HER2 gene in the breast cancer is closely associated with the invasion resulting in distant metastasis [2]. Current strategies in breast cancer treatment include surgery, radiation therapy, chemotherapy, endocrine therapy (for hormone receptor-positive disease), and recently immunotherapy; however, breast cancer with distant organ metastases is considered incurable using currently available therapies. In addition, breast cancers are most often angiogenic with poor prognosis [3]. Survival of metastatic cells and tumor progression require nutrients and an adequate supply of oxygen; therefore, they need to stay in close proximity to blood capillaries for direct contact of the circulatory system. In tumor angiogenesis, a range of secreted factors and signaling pathways together with participation of non-endothelial cells are organized the process [4]. Hypoxia and nutrient deprivation triggers an “angiogenic switch” in tumor progression, when the tumor starts growing and finally reaches a few millimeters in diameter [5]. Although tumor angiogenesis has been a primary target, it is also a major challenge in cancer therapy. In 2003, humanized neutralizing antibodies targeting anti-vascular endothelial growth factor (VEGF) was approved by the U.S. Food and Drug Administration (FDA) leading to prolonged survival rate of metastatic colorectal cancer [6]. Trastuzumab, the first humanized monoclonal antibody, binds the extracellular domain of HER2 overexpressed in invasive breast cancer tumors. Overexpression of HER2 is closely related to increased expression of VEGF and angiogenesis. In 2020, FDA approved trastuzumab to treat HER2 positive breast cancer, which has metastasized [7,8]. In addition, antiangiogenic activity of trastuzumab has been reported in breast cancer by modulation of different proand anti-angiogenic agents [9–11]. Despite the advanced research in last decades, it is further required to explore new strategies in cancer therapy because of inability of delivering an adequate amount of cancer medicines to the tumor area without side effects. Nanotechnology suggests the exploitation of biocompatible and biodegradable systems, which can improve the bioavailability of drugs at the targeted area [12]. Recently, an innovative approach in cancer nanomedicine has been proposed based on the use of nanomaterials that can remotely respond to external irradiation such as ultrasound [13]. In this context, piezoelectric nanomaterials featuring the capability of converting mechanical energy to electricity represent great potential in cancer therapy due to non-invasive and remote delivery of electrical signal to determine cell fate [14]. In a previous work performed by the group where I currently work at the IIT Center for Materials Interfaces, for the first time a wireless treatment based on piezoelectric barium titanate nanoparticles has been exploited for remote delivering of electric stimulation to breast cancer cells [15]. In addition, our recent study demonstrated that piezoelectric poly(vinylidene fluoride-trifluoro ethylene) nanoparticles can be used to inhibit cell migration and invasion ability of glioblastoma cells upon ultrasound stimulation [16]. However, most of piezoelectric nanomaterials (such as zinc oxide and barium titanate) show low biocompatibility and biodegradability [17]. Nylon, a polyamide and bioplastic, is usually used as a coating material, surgical suture, and scaffold. It is known that oddnumbered nylons (e.g., 7, 9, and 11) have efficient piezoelectricity, and among them nylon-11 has been recently used in energy harvesting due to piezoelectric properties [18]. Until now, the piezoelectricity of nylon-11 has not been reported in tumor angiogenesis or metastasis. This project proposes to develop trastuzumab decorated nylon-11 nanovectors in order to improve the therapeutic efficiency in breast cancer angiogenesis in in vitro and in vivo. The therapy will be further accompanied by ultrasound stimuli thanks to the nylon-11 piezoelectric property.