Date of Award
Fall 2025
Document Type
Open Access Dissertation
Department
College of Pharmacy
First Advisor
Hippokratis Kiaris
Abstract
The chemokine CCL8 (monocyte chemoattractant protein-2) is a versatile signaling molecule involved in tumor progression, immune cell recruitment, and therapeutic resistance. Through activation of receptors including CCR1, CCR2B, and CCR5, CCL8 promotes leukocyte trafficking, epithelial–mesenchymal transition, and the establishment of immunosuppressive tumor microenvironments. In breast cancer and inflammatory diseases, elevated CCL8 levels correlate with poor clinical outcomes, making it a promising therapeutic target.
A strategy was developed to block CCL8 activity and selectively ablate CCL8 receptor expressing cells. A neutralizing monoclonal antibody, 1G3E5, was identified from a panel of murine candidates based on high affinity CCL8 binding. Sequencing revealed two variable light chain sequences, and the correct variant was incorporated into a functional human IgG1 chimera. In vivo evaluation of 1G3E5 in a lipopolysaccharide-induced lung injury model in Peromyscus maniculatus demonstrated reduced pulmonary inflammation and suppressed cytokine induction. These findings validate CCL8 as a mediator of inflammatory amplification and support 1G3E5 as a therapeutic candidate.
To complement ligand neutralization, receptor targeted cytotoxic fusion proteins were generated by linking human CCL8 to the truncated diphtheria toxin DT386. The resulting construct, DTCCL8, inhibited tumor growth in a PyMT breast cancer transplant model in C57BL/6 mice. Expanded studies using human breast cancer models confirmed therapeutic potential for DTCCL8 and a related construct, DTCCL2. In NU/J mice, DTCCL8 reduced tumor volumes in xenografts established with BT549 and MDA-MB-231 cells. In NSG mice bearing patient-derived xenografts of triple-negative breast cancer, both DTCCL2 and DTCCL8 produced significant tumor suppression. Across all in vivo models, cultured tumor explants stained with DAPI showed consistent nuclear shrinkage, supporting a cytotoxic mechanism of action in receptor expressing cells. Finally, a transcriptome wide correlation methodology was employed to identify paracrine regulators of cancer cell migration. Fibroblast gene expression profiles were linked to their ability to induce breast cancer cell migration, and genes with strong correlations were frequently associated with metastasis, validating this approach as a screening tool.
Collectively, these findings establish a dual therapeutic platform targeting the CCL8 axis in breast cancer, integrating ligand neutralization and receptor specific cytotoxicity. This work supports the development of chemokine targeted therapies and highlights the potential of transcriptome guided strategies for identifying tumor modifying paracrine signals.
Rights
© 2025, Bernardo Chavez
Recommended Citation
Chavez, B.(2025). Development of a Strategy to Neutralize CCL8 Activity and Ablate CCL8 Cellular Targets. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/8686