Targeting EphA2 in Bladder Cancer Using a Novel Antibody-Directed Nanotherapeutic

Development of an Anti-EphB4 Monoclonal Antibody for Multiple Applications Against Breast Cancers

The erythropoietin-producing hepatocellular carcinoma (Eph) receptors are the largest receptor tyrosine kinase family. EphB4 is essential for cell adhesion and motility during embryogenesis. Pathologically, EphB4 is overexpressed and contributes to poor prognosis in various tumors. Therefore, specific monoclonal antibodies (mAbs) should be developed to predict the prognosis for multiple tumors with high EphB4 expression, including breast and gastric cancers. This study aimed to develop specific anti-EphB4 mAbs for multiple applications using the Cell-Based Immunization and Screening method. EphB4-overexpressed Chinese hamster ovary (CHO)-K1 (CHO/EphB4) cells were immunized into mice, and we established an anti-EphB4 mAb (clone B4Mab-7), which is applicable for flow cytometry, Western blot, and immunohistochemistry (IHC). B4Mab-7 reacted with endogenous EphB4-positive breast cancer cell line, MCF-7, but did not react with EphB4-knockout MCF-7 (BINDS-52) in flow cytometry. Dissociation constant (KD) values were determined to be 2.9 × 10-9 M and 1.3 × 10-9 M by flow cytometric analysis for CHO/EphB4 and MCF-7 cells, respectively. B4Mab-7 detected the EphB4 protein bands from breast cancer cells in Western blot, and stained breast cancer tissues in IHC. Altogether, B4Mab-7 is very useful for detecting EphB4 in various applications.

Lipid Nanoparticles Functionalized with Antibodies for Anticancer Drug Therapy

Nanotechnology takes the lead in providing new therapeutic options for cancer patients. In the last decades, lipid-based nanoparticles-solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), liposomes, and lipid-polymer hybrid nanoparticles-have received particular interest in anticancer drug delivery to solid tumors. To improve selectivity for target cells and, thus, therapeutic efficacy, lipid nanoparticles have been functionalized with antibodies that bind to receptors overexpressed in angiogenic endothelial cells or cancer cells. Most papers dealing with the preclinical results of antibody-conjugated nanoparticles claim low systemic toxicity and effective tumor inhibition, which have not been successfully translated into clinical use yet. This review aims to summarize the current "state-of-the-art" in anticancer drug delivery using antibody-functionalized lipid-based nanoparticles. It includes an update on promising candidates that entered clinical trials and some explanations for low translation success.

State-of-the-Art Advances of Nanomedicine for Diagnosis and Treatment of Bladder Cancer

Bladder cancer is a common malignant tumor of the urinary system. Cystoscopy, urine cytology, and CT are the routine diagnostic methods. However, there are some problems such as low sensitivity and difficulty in staging, which must be urgently supplemented by novel diagnostic methods. Surgery, intravesical instillation, systemic chemotherapy, and radiotherapy are the main clinical treatments for bladder cancer. It is difficult for conventional treatment to deal with tumor recurrence, progression and drug resistance. In addition, the treatment agents usually have the defects of poor specific distribution ability to target tumor tissues and side effects. The rapid development of nanomedicine has brought hope for the treatment of bladder cancer in reducing side effects, enhancing tumor inhibition effects, and anti-drug resistance. Overall, we review the new progression of nano-platforms in the diagnosis and treatment of bladder cancer.

EphA2 on urinary extracellular vesicles as a novel biomarker for bladder cancer diagnosis and its effect on the invasiveness of bladder cancer

BACKGROUND

Urinary extracellular vesicles (uEVs) secreted from bladder cancer contain cancer-specific proteins that are potential diagnostic biomarkers. We identified and evaluated a uEV-based protein biomarker for bladder cancer diagnosis and analysed its functions.

METHODS

Biomarker candidates, selected by shotgun proteomics, were validated using targeted proteomics of uEVs obtained from 49 patients with and 48 individuals without bladder cancer, including patients with non-malignant haematuria. We developed an enzyme-linked immunosorbent assay (ELISA) for quantifying the uEV protein biomarker without ultracentrifugation and evaluated urine samples from 36 patients with and 36 patients without bladder cancer.

RESULTS

Thirteen membrane proteins were significantly upregulated in the uEVs from patients with bladder cancer in shotgun proteomics. Among them, eight proteins were validated by target proteomics, and Ephrin type-A receptor 2 (EphA2) was the only protein significantly upregulated in the uEVs of patients with bladder cancer, compared with that of patients with non-malignant haematuria. The EV-EphA2-CD9 ELISA demonstrated good diagnostic performance (sensitivity: 61.1%, specificity: 97.2%). We showed that EphA2 promotes proliferation, invasion and migration and EV-EphA2 promotes the invasion and migration of bladder cancer cells.

CONCLUSIONS

We established EV-EphA2-CD9 ELISA for uEV-EphA2 detection for the non-invasive early clinical diagnosis of bladder cancer.

Taxanes prodrug-based nanomedicines for cancer therapy

Malignant tumor remains a huge threat to human health and chemotherapy still occupies an important place in clinical tumor treatment. As a kind of potent antimitotic agent, taxanes act as the first-line broad-spectrum cancer drug in clinical use. However, disadvantages such as prominent hydrophobicity, severe off-target toxicity or multidrug resistance lead to unsatisfactory therapeutic effects, which restricts its wider usage. The efficient delivery of taxanes is still quite a challenge despite the rapid developments in biomaterials and nanotechnology. Great progress has been made in prodrug-based nanomedicines (PNS) for cancer therapy due to their outstanding advantages such as high drug loading efficiency, low carrier induced immunogenicity, tumor stimuli-responsive drug release, combinational therapy and so on. Based on the numerous developments in this filed, this review summarized latest updates of taxanes prodrugs-based nanomedicines (TPNS), focusing on polymer-drug conjugate-based nanoformulations, small molecular prodrug-based self-assembled nanoparticles and prodrug-encapsulated nanosystems. In addition, the new trends of tumor stimuli-responsive TPNS were also discussed. Moreover, the future challenges of TPNS for clinical translation were highlighted. We here expect this review will inspire researchers to explore more practical taxanes prodrug-based nano-delivery systems for clinical use.