Related Experiment Video
Updated: Nov 3, 2025
MR Molecular Imaging of Prostate Cancer with a Small Molecular CLT1 Peptide Targeted Contrast Agent
Published on: September 3, 2013
A Single-Domain Antibody-Based Anti-PSMA Recombinant Immunotoxin Exhibits Specificity and Efficacy for Prostate
Yutong Xing1, Keyuan Xu1, Shixiong Li1
1State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China.
Abstract:
Prostate cancer (PCa) is the second most common cancer in men, causing more than 300,000 deaths every year worldwide. Due to their superior cell-killing ability and the relative simplicity of their preparation, immunotoxin molecules have great potential in the clinical treatment of cancer, and several such molecules have been approved for clinical application. In this study, we adopted a relatively simple strategy based on a single-domain antibody (sdAb) and an improved Pseudomonas exotoxin A (PE) toxin (PE24X7) to prepare a safer immunotoxin against prostate-specific membrane antigen (PSMA) for PCa treatment. The designed anti-PSMA immunotoxin, JVM-PE24X7, was conveniently prepared in its soluble form in an Escherichia coli (E. coli) system, avoiding the complex renaturation process needed for immunotoxin preparation by the conventional strategy. The product was very stable and showed a very strong ability to bind the PSMA receptor. Cytotoxicity assays showed that this molecule at a very low concentration could kill PSMA-positive PCa cells, with an EC50 value (concentration at which the cell viability decreased by 50%) of 15.3 pM against PSMA-positive LNCaP cells. Moreover, this molecule showed very good killing selectivity between PSMA-positive and PSMA-negative cells, with a selection ratio of more than 300-fold. Animal studies showed that this molecule at a very low dosage (5 × 0.5 mg/kg once every three days) completely inhibited the growth of PCa tumors, and the maximum tolerable dose (MTD) was more than 15 mg/kg, indicating its very potent tumor-treatment ability and a wide therapeutic window. Use of the new PE toxin, PE24X7, as the effector moiety significantly reduced off-target toxicity and improved the therapeutic window of the immunotoxin. The above results demonstrate that the designed anti-PSMA immunotoxin, JVM-PE24X7, has good application value for the treatment of PCa.
Insights
Researchers developed a novel immunotoxin, JVM-PE24X7, for prostate cancer (PCa) treatment. This engineered molecule effectively targets prostate-specific membrane antigen (PSMA)-positive cancer cells, showing potent tumor inhibition and reduced toxicity in preclinical studies.
Area of Science:
- Oncology
- Immunology
- Biotechnology
Background:
- Prostate cancer (PCa) is a leading cause of cancer death in men globally.
- Immunotoxins offer a promising therapeutic strategy for cancer treatment due to their targeted cell-killing capabilities.
- Existing immunotoxin development often involves complex preparation and potential off-target toxicities.
Purpose of the Study:
- To develop a novel, safer, and more effective immunotoxin for prostate cancer treatment.
- To utilize a single-domain antibody (sdAb) and an improved Pseudomonas exotoxin A (PE24X7) for targeting prostate-specific membrane antigen (PSMA).
- To evaluate the efficacy, specificity, and safety profile of the designed immunotoxin, JVM-PE24X7.
Main Methods:
- Engineered a single-domain antibody (sdAb) targeting PSMA linked to an improved Pseudomonas exotoxin A (PE24X7).
- Produced the immunotoxin JVM-PE24X7 in an Escherichia coli (E. coli) system for simplified preparation.
- Assessed binding affinity, in vitro cytotoxicity against PSMA-positive and negative cells, and in vivo tumor growth inhibition in animal models.
Main Results:
- JVM-PE24X7 was efficiently produced in a soluble form in E. coli, demonstrating high stability and strong PSMA binding.
- The immunotoxin exhibited potent cytotoxicity against PSMA-positive PCa cells (EC50 = 15.3 pM) with high selectivity (>300-fold) over PSMA-negative cells.
- In vivo studies showed complete inhibition of PCa tumor growth at low dosages and a maximum tolerable dose exceeding 15 mg/kg, indicating a wide therapeutic window.
Conclusions:
- The novel anti-PSMA immunotoxin JVM-PE24X7 demonstrates significant potential for effective and safe prostate cancer treatment.
- The simplified production strategy and the use of PE24X7 toxin reduced off-target toxicity and improved the therapeutic index.
- JVM-PE24X7 exhibits potent anti-tumor activity and a favorable safety profile, warranting further clinical investigation for PCa therapy.
