Platelets Enhance Multiple Myeloma Progression via IL-1β Upregulation.

Tumor cell-platelet interactions contribute to tumor progression and metastasis in solid tumors. However, the role of platelets in hematological malignancies is not clear. We investigated the association of platelet activation status with clinical stages in multiple myeloma (MM) patients and explored the role of platelets in MM progression. Platelets were obtained from healthy donors and MM patients. We examined platelet activation status in MM patients by flow cytometry and transmission electron microscopy. We also observed the enriched pathways that are involved with platelet activation in RNA sequencing of platelets. MM cell lines were used to assess the effect of platelets on MM cell proliferation and their engraftment RNA sequencing of MM cell lines was performed to explore molecular mechanisms underlying MM cell-platelet interaction and a CRISPR/Cas9 knockout approach was used for validation. Platelets from MM patients were highly activated with disease progression. RNA sequencing of platelets revealed that genes involved in platelets were enriched in patients with smoldering MM (SMM) or MM. Platelets promoted MM cell proliferation and contributed to tumor engraftment in bone marrow RNA sequencing revealed that was upregulated in MM cell lines co-cultured with platelets, whereas knockout in MM cell lines abrogated the effects of platelets on MM cell proliferation and engraftment Platelets from MM patients were highly activated with disease progression. IL-1β is critical to platelet-mediated MM progression and might be a potential target for MM treatment. .