Transcriptomics of Canine Inflammatory Mammary Cancer Treated with Empty Cowpea Mosaic Virus Implicates Neutrophils in Anti-Tumor Immunity

Abstract

Canine inflammatory mammary cancer (IMC) is a highly aggressive and lethal cancer in dogs serving as a valuable animal model for its human counterpart, inflammatory breast cancer (IBC), both lacking effective therapies. Intratumoral immunotherapy (IT-IT) with empty cowpea mosaic virus (eCPMV) nanoparticles has shown promising results, demonstrating a reduction in tumor size, longer survival rates, and improved quality of life. This study compares the transcriptomic profiles of tumor samples from female dogs with IMC receiving eCPMV IT-IT and medical therapy (MT) versus MT alone. Transcriptomic analyses, gene expression profiles, signaling pathways, and cell type profiling of immune cell populations in samples from four eCPMV-treated dogs with IMC and four dogs with IMC treated with MT were evaluated using NanoString Technologies using a canine immune-oncology panel. Comparative analyses revealed 34 differentially expressed genes between treated and untreated samples. Five genes (CXCL8, S100A9, CCL20, IL6, and PTGS2) involved in neutrophil recruitment and activation were upregulated in the treated samples, linked to the IL17-signaling pathway. Cell type profiling showed a significant increase in neutrophil populations in the tumor microenvironment after eCPMV treatment. These findings highlight the role of neutrophils in the anti-tumor response mediated by eCPMV IT-IT and suggest eCPMV as a novel therapeutic approach for IBC/IMC.

Intratumoral delivery of immunotherapy to treat breast cancer: current development in clinical and preclinical studies

“…In a follow-up study, a transcriptomal analysis of canine patients with inflammatory BC again treated with eCPMV revealed an increase in neutrophil recruitment and activation transcriptional profile ( 109 ). Tumors in this study also decreased in all six treated patients, which allowed three patients to undergo surgical treatment ( 109 ).…”

“…delivery outperformed subcutaneous delivery when tested in two studies ( 86 , 103 ). In the neoadjuvant setting, treatment allowed patients in canine studies to undergo surgery when previously surgery had not been an option ( 108 , 109 ), providing additional rationale to pursue i.t. viral therapy in the neoadjuvant setting.…”

“…Immunotherapy promises to boost tumor specific immunity that eliminates residual cancer cells after surgery and prevents recurrence. Promising results from the clinical trials NCT02018458 ( 49 ), NCT02061332 ( 47 ), and NCT02779855 ( 62 ) and from the preclinical studies ( 108 , 109 , 120 – 122 , 144 , 145 ) encourage more consideration for neoadjuvant i.t. immunotherapy studies in further preclinical research and in developing clinical trials.…”

Improved characterization and translation of NK cells for canine immunotherapy

“…The same immune profiling method was used to investigate the abundance of NK cells in the TME of dogs with canine inflammatory mammary cancer treated with intratumor delivery of immunotherapy using empty cowpea mosaic virus-like particles (eCPMV) ( 27 ), which are recognized by toll-like receptors (TLRs). They found no significant change in cells labeled as “NK CD56dim cells,” or cells enriched for IL21R, and the fold change of other genes associated with NK cells including KLRA1, KLRD1, and GZMB were increased in treated tumor tissue, but not significantly ( 27 ).…”

“…The same immune profiling method was used to investigate the abundance of NK cells in the TME of dogs with canine inflammatory mammary cancer treated with intratumor delivery of immunotherapy using empty cowpea mosaic virus-like particles (eCPMV) ( 27 ), which are recognized by toll-like receptors (TLRs). They found no significant change in cells labeled as “NK CD56dim cells,” or cells enriched for IL21R, and the fold change of other genes associated with NK cells including KLRA1, KLRD1, and GZMB were increased in treated tumor tissue, but not significantly ( 27 ). Conversely, there was significant upregulation in treated versus untreated tumor tissue of IL18R1 and significant downregulation of IL12RB2, which are both implicated in NK cell functions ( 27 ), supporting the pattern across canine immunotherapies in which both activation and inhibition are observed simultaneously.…”