Single Cell Mass Cytometry Revealed the Immunomodulatory Effect of Cisplatin Via Downregulation of Splenic CD44+, IL-17A+ MDSCs and Promotion of Circulating IFN-γ+ Myeloid Cells in the 4T1 Metastatic Breast Cancer Model

Abstract

The treatment of metastatic breast cancer remained a challenge despite the recent breakthrough in the immunotherapy regimens. Here, we addressed the multidimensional immunophenotyping of 4T1 metastatic breast cancer by the state-of-the-art single cell mass cytometry (CyTOF). We determined the dose and time dependent cytotoxicity of cisplatin on 4T1 cells by the xCelligence real-time electronic sensing assay. Cisplatin treatment reduced tumor growth, number of lung metastasis, and the splenomegaly of 4T1 tumor bearing mice. We showed that cisplatin inhibited the tumor stroma formation, the polarization of carcinoma-associated fibroblasts by the diminished proteolytic activity of fibroblast activating protein. The CyTOF analysis revealed the emergence of CD11b+/Gr-1+/CD44+ or CD11b+/Gr-1+/IL-17A+ myeloid-derived suppressor cells (MDSCs) and the absence of B220+ or CD62L+ B-cells, the CD62L+/CD4+ and CD62L+/CD8+ T-cells in the spleen of advanced cancer. We could show the immunomodulatory effect of cisplatin via the suppression of splenic MDSCs and via the promotion of peripheral IFN-γ+ myeloid cells. Our data could support the use of low dose chemotherapy with cisplatin as an immunomodulatory agent for metastatic triple negative breast cancer.

Imidazo[1,2-b]pyrazole-7-Carboxamide Derivative Induces Differentiation-Coupled Apoptosis of Immature Myeloid Cells Such as Acute Myeloid Leukemia and Myeloid-Derived Suppressor Cells

“…Female Charles River-derivative BALB/c mice (8–10 weeks old) were purchased from Kobay Ltd., (Ankara, Turkey) and were injected orthotopically with 4T1 breast carcinoma cells (1.2 × 10 5 cells in 100 μL PBS) or sham injected with 100 μL PBS as described previously [ 29 ]. The animals had free access to food and water.…”

“…We have previously reviewed the contribution of MDSCs to the tumor microevolution [23,28] and showed the expansion of these immature myeloid cells in the spleen of 4T1 breast cancer bearing mice [29]. Here, we addressed to investigate the effect of DU325 treatment on the viability of these MDSCs ex vivo.…”

“…Mass cytometry was performed as described previously with minor modifications [29,86]. Briefly, 1.5 × 10 6 cells were plated in six-well plates for the treatment by 40 nM or 200 nM DU325 or left untreated (untr.)…”

“…These protumoral functions of MDSCs offer a myriad of potential anticancer therapeutic targets that we have previously reviewed [28]. We have recently reported the immunomodulatory effect of cisplatin via the suppression of splenic MDSCs in the 4T1 murine breast cancer model [29].…”

Progress and applications of mass cytometry in sketching immune landscapes

“…With relative high cellular throughput and high dimensions, CyTOF is an ideal and potent technique that reveals intratumor heterogeneity in a variety of tumors, including breast, [70][71][72][73] lung, [74][75][76][77] oropharyngeal, 78 brain, [79][80][81][82][83] colon, 7,11,84,85 ovarian, 86,87 kidney, 88,89 gastric cancer, 90,91 leukemia and lymphoma, 19,[92][93][94][95] and melanoma. 96,97 A summary of single-cell CyTOF studies on primary tumors of various human cancers is presented in Table 3.…”