Cabral, M. G. | Search bioRxiv

bioRxiv2021

Circulating Low Density Neutrophils of Breast Cancer Patients are Associated with their Worse Prognosis due to the Impairment of T cell Responses

Neutrophils are prominent immune components of solid tumors, which can protect against the onset of cancer (N1) or have pro-tumor activity (N2). Circulating neutrophils, divided into high density neutrophils (HDN) and low density neutrophils (LDN), functionally mirror those N1 and N2 cells, respectively. LDN, a rare subset in non-pathological conditions, have been extensively studied in cancer, due to their frequency in this disease and their pro-tumor phenotype. However, this has been mainly demonstrated in animal models and proper validation in humans is an urgent need. Here, we further enlighten the clinical impact of LDN in a cohort of breast cancer (BC) patients. We observed that LDN were practically absent in healthy donors blood, while were significantly increased in the blood of BC patients, particularly with metastatic disease. Relevant for a clinical translation, within the population of non-metastatic patients, LDN were more prevalent in patients with poor response to neoadjuvant chemotherapy than in responders. The association of a higher incidence of circulating LDN and the worse prognosis of BC patients could be explained by the pro-tumor/immunosuppressive characteristics exhibited by these cells. Namely, there are more LDN expressing the immunosuppressive marker PD-L1, than HDN. Additionally, LDN also showed increased expression of activation markers; a robust formation of neutrophil extracellular traps; an augmented phagocytic activity; and a higher capacity to release reactive oxygen species, which may contribute for tumor development and metastization. Moreover, the percentage of LDN in BC patients blood was negatively correlated with activated cytotoxic T lymphocytes and positively correlated with the immunosuppressive CCR4+ regulatory T cells, corroborating their impairment on the anti-tumor immune responses, which was further demonstrated ex vivo. Hence, this study reveals the potential of LDN as a clinical meaningful biomarker of BC response to treatment and opens new avenues for developing targeted immunotherapies.

immunology↗

bioRxiv2020

Differential expression between African-ancestry and White patients diagnosed with Triple-Negative Breast Cancer: EGFR, Myc, Bcl2 and β-Catenin as ancestry-associated markers

PurposeTriple-negative breast cancer (TNBC) has a higher incidence, a younger age of onset, and a more aggressive behavior in African-ancestry women. Biological disparities have been suggested as an important factor influencing the ancestry-associated TNBC discrepancy. In this study, we sought to identify ancestry-associated differential gene and protein expression between African-ancestry and White TNBC patients, controlling for patients menopause status and pathological staging at diagnosis. MethodsDifferential gene expression analyses (DGEA) were performed using RNA-sequencing data from The Cancer Genome Atlas (TCGA). Gene set enrichment analysis (GSEA) and Ingenuity Pathway Analysis (IPA), with focus on network design, were performed to highlight candidate genes for further validation through immunohistochemistry of TNBC samples from patients followed in Portugal. ResultsWith 52 African-American and 90 White TNBC patients included, TCGAs data corroborate that African-American patients have a higher TNBC incidence (28.42% vs 11.89%, p<0.0001). Particularly, premenopausal and stage II disease African-American patients also have significantly lower survival probability, comparing with White patients (log-rank p=0.019 and 0.0038, respectively). DGEA results suggest that expression profile differences are more associated with TNBC staging than with patients menopause status. Hippo pathway and cellular community gene sets are downregulated, while breast cancer gene set is upregulated in African-Americans, comparing with White TNBC patients. Furthermore, MAPK pathway gene set is upregulated when controlling for stage II disease. Due to their central role in highly scored networks resulted from IPAs network design, EGFR, Myc and Bcl2 genes were selected for further validation through immunohistochemistry. We also included {beta}-Catenin in the validation study as it is consensually reported to be required in TNBC tumorigenesis. Although patients used in the DGEA and in the immunohistochemistry experiments are geographically and culturally distinct, both groups of African-ancestry patients are mostly of western-African ancestry and, interesting, differential gene and protein expression matched. ConclusionsWe found ancestry-associated gene expression patterns between African-ancestry and White TNBCs, particularly when controlling for menopause status or staging. EGFR, Myc, Bcl2 and {beta}-catenin gene and protein differential expression matching results in distinct populations suggest these markers as being important indicators of TNBCs ancestry-associated development.

cancer biology↗