Crotamine-based recombinant immunotoxin targeting HER2 for enhanced cancer cell specificity and cytotoxicity

Development and Characterization of an Anti-PD-L1 Immunotoxin for Targeted Cancer Therapy

BACKGROUND

Immunotoxins (ITs) represent a novel class of therapeutics with bifunctional structures that facilitate their penetration through cell membranes to induce target cell destruction. Programmed cell death ligand-1 (PD-L1), a human cell surface protein, is overexpressed in various cancers. This study aimed to construct a novel IT by genetically fusing an anti-PD-L1 Nanobody (Nb) to a truncated diphtheria toxin (DT).

METHODS

The IT construct comprised a 127-amino acid anti-PD-L1 Nb fused to a 380-amino acid fragment of DT, with an N-terminal 6x-His tag. Molecular cloning techniques were employed, followed by transformation and verification through colony-PCR, enzyme digestion, and sequencing. The anti-PD-L1 Nb was expressed in WK6 E. coli cells induced by Isopropyl β-D-1- Thiogalactopyranoside (IPTG) and purified from periplasmic extracts using immobilized Metal Ion Affinity hromatography (IMAC). The IT was similarly expressed, purified, and validated via SDS-PAGE and Western blot analysis.

RESULTS

ELISA confirmed the binding activity of both Nb and IT to immobilized PD-L1 antigen, whereas truncated DT exhibited no binding. MTT assays demonstrated significant cytotoxicity of IT on A-431 cell lines compared to Nb and truncated DT controls. Statistical analyses underscored the significance of these findings.

CONCLUSION

This study provides a thorough characterization of the constructed IT, highlighting its potential as a therapeutic agent targeting PD-L1-expressing cancer cells. The results support the potential of this IT in cancer immunotherapy, emphasizing the need for further investigation into its efficacy and safety profiles.

Role of Proteins in Oncology: Advances in Cancer Diagnosis, Prognosis, and Targeted Therapy-A Narrative Review

Modern oncology increasingly relies on the role of proteins as key components in cancer diagnosis, prognosis, and targeted therapy. This review examines advancements in protein biomarkers across several cancer types, including breast cancer, lung cancer, ovarian cancer, and hepatocellular carcinoma. These biomarkers have proven critical for early detection, treatment response monitoring, and tailoring personalized therapeutic strategies. The article highlights the utility of targeted therapies, such as tyrosine kinase inhibitors and monoclonal antibodies, in improving treatment efficacy while minimizing systemic toxicity. Despite these advancements, challenges like tumor resistance, variability in protein expression, and diagnostic heterogeneity persist, complicating universal application. The review underscores future directions, including the integration of artificial intelligence, advanced protein analysis technologies, and the development of combination therapies to overcome these barriers and refine personalized cancer treatment.

Enhanced prokaryotic expression, purification, and biological activities of human keratinocyte growth factor

Keratinocyte growth factor (KGF), also known as fibroblast growth factor 7 (FGF7), plays a critical role in embryonic development, cell proliferation, and differentiation. However, efficient production of recombinant KGF remains a challenge due to its low expression levels and high tendency for aggregation in Escherichia coli. This study aimed to enhance the expression and solubility of KGF by employing different protein tags-PDIb'a', MBP, and His-fused to the N-terminus of KGF. Among these, H-PDIb'a'-KGF demonstrated superior stability and was selected for large-scale production and purification. The purified KGF was confirmed through liquid chromatography with tandem mass spectrometry analysis, which showed an 81% fragment mass identification coverage. Biological activity assessments using human breast cancer MCF-7 cells indicated that purified KGF significantly increased cell proliferation, with an EC50 of 6.4 ± 0.5 pM. Interestingly, PDIb'a' alone also exhibited a stimulatory effect on MCF-7 cells. Furthermore, the purified KGF enhanced the wound healing of HaCaT keratinocytes in a dose-dependent manner. These findings provide valuable insights into the efficient production and functional characterization of recombinant KGF for potential applications in therapeutic interventions.