In melanoma, immature myeloid cells are found to be recruited and accumulated at the tumor site and differentiate into myeloid-derived suppressor cells with a potent ability to inhibit Ag-specific immune responses. The mechanism behind this differentiation is still unclear.
The accumulation of myeloid-derived suppressor cells has been shown to be an indicator in the blood of patients in all stages of melanoma, including early-stage I. Immature myeloid cells, as the progenitors of myeloid-derived suppressor cells, are 15 times more abundant in the skin of melanoma patients than in healthy controls. The association between immature myeloid cells and the establishment of tumors is not well understood. This project aims to understand the role of immature myeloid cells in the establishment of early-stage melanoma by exploring the direct and indirect capacity of myeloid lineages to impact tumor establishment and early growth.
This project aimed to explore the impact of depleting immature myeloid cells on tumor establishment by systematically removing these cells before tumor challenge. The study also investigated the interactions between myeloid-derived suppressor cells and T cells by co-culture them in vitro. Publicly available spatial transcriptomic data was utilized to identify the spatial relationship between immature myeloid cells/myeloid-derived suppressor cells with tumors, their specific interactions with other cells, and the growth and angiogenic factors they produce. Additionally, a timeline of myeloid lineage trajectory was identified in the tumor environment using a 23 markers panel single-cell proteomics via flow cytometry.