Breast cancer is the most common malignant disease in women worldwide, but the current drug therapy is far from optimal as indicated by the high death rate of breast cancer patients. Nanomedicine is a promising alternative for breast cancer treatment. Nanomedicine products such as Doxil ® and Abraxane ® have already been extensively used for breast cancer adjuvant therapy with favorable clinical outcomes. However, these products were originally designed for generic anticancer purpose and not specifically for breast cancer treatment. With better understanding of the molecular biology of breast cancer, a number of novel promising nanotherapeutic strategies and devices have been developed in recent years. In this review, we will first give an overview of the current breast cancer treatment and the updated status of nanomedicine use in clinical setting, then discuss the latest important trends in designing breast cancer nanomedicine, including passive and active cancer cell targeting, breast cancer stem cell targeting, tumor microenvironment-based nanotherapy and combination nanotherapy of drug-resistant breast cancer. Researchers may get insight from these strategies to design and develop nanomedicine that is more tailored for breast cancer to achieve further improvements in cancer specificity, antitumorigenic effect, antimetastasis effect and drug resistance reversal effect.

As an essential component of immunotherapy, monoclonal antibodies (mAbs) have emerged as a class of powerful therapeutics for treatment of a broad range of diseases. For central nervous system (CNS) diseases, however, the efficacy remains limited due to their inability to enter the CNS. A platform technology is reported here that enables effective delivery of mAbs to the CNS for brain tumor therapy. This is achieved by encapsulating the mAbs within nanocapsules that contain choline and acetylcholine analogues; such analogues facilitate the penetration of the nanocapsules through the brain–blood barrier and the delivery of mAbs to tumor sites. This platform technology uncages the therapeutic power of mAbs for various CNS diseases that remain poorly treated.

Approximately 15-40% of all cancers develop metastases in the central nervous system (CNS), yet few therapeutic options exist to treat them. Cancer therapies based on monoclonal antibodies are widely successful, yet have limited efficacy against CNS metastases, owing to the low levels of the drug reaching the tumour site. Here, we show that the encapsulation of rituximab within a crosslinked zwitterionic polymer layer leads to the sustained release of rituximab as the crosslinkers are gradually hydrolyzed, enhancing by approximately 10-fold the CNS levels of the antibody with respect to the administration of naked rituximab. When the nanocapsules are functionalized with CXCL13, the ligand for the chemokine receptor CXCR5 frequently found on B-cell lymphoma, a single dose led to improved control of CXCR5-expressing metastases in a murine xenograft model of non-Hodgkin lymphoma, and eliminated lymphoma in a xenografted humanized bone-marrow-liver-thymus mouse model. Encapsulation and molecular targeting of therapeutic antibodies could become an option for the treatment of cancers with CNS metastases. Treatments for cancer metastases, especially those of the central nervous system (CNS), are less successful than those for primary tumors 1. Approximately 15%−40% of all cancers develop a CNS metastasis 2,3 , which most commonly arises from lung cancer, melanoma, breast cancer, and colorectal cancer. Therapeutic monoclonal antibodies (mAbs) have revolutionized the treatment of cancer; however, their efficacy is limited in patients with CNS metastases due to insufficient mAb CNS delivery-typically 0.1% of the levels in plasma 4. By bypassing the blood-brain barrier (BBB) through intrathecal or intraventricular administration, mAb therapy has shown some effectiveness against CNS tumor metastases 4-10. However, direct CNS administration is invasive, with potential for neurotoxicity, and is limited by rapid efflux of antibodies from the CNS within hours 5,10,11. Therefore, novel approaches for mAbs delivery are preferable to maintain systemic therapeutic effect in the CNS with improved efficiency.

The central nervous system (CNS) plays a central role in the control of sensory and motor functions, and the disruption of its barriers can result in severe and debilitating neurological disorders. Neurotrophins are promising therapeutic agents for neural regeneration in the damaged CNS. However, their penetration across the blood–brain barrier remains a formidable challenge, representing a bottleneck for brain and spinal cord therapy. Herein, a nanocapsule‐based delivery system is reported that enables intravenously injected nerve growth factor (NGF) to enter the CNS in healthy mice and nonhuman primates. Under pathological conditions, the delivery of NGF enables neural regeneration, tissue remodeling, and functional recovery in mice with spinal cord injury. This technology can be utilized to deliver other neurotrophins and growth factors to the CNS, opening a new avenue for tissue engineering and the treatment of CNS disorders and neurodegenerative diseases.

Central nervous system (CNS) diseases are the leading cause of morbidity and mortality; their treatment, however, remains constrained by the blood–brain barrier (BBB) that impedes the access of most therapeutics to the brain. A CNS delivery platform for protein therapeutics, which is achieved by encapsulating the proteins within nanocapsules that contain choline and acetylcholine analogues, is reported herein. Mediated by nicotinic acetylcholine receptors and choline transporters, such nanocapsules can effectively penetrate the BBB and deliver the therapeutics to the CNS, as demonstrated in mice and non‐human primates. This universal platform, in general, enables the delivery of any protein therapeutics of interest to the brain, opening a new avenue for the treatment of CNS diseases.