Combination of JAKi and HDACi Exerts Antiangiogenic Potential in Cutaneous T-Cell Lymphoma.

Simple Summary: The combination of JAK/HDAC inhibitors shows beneficial effects in hematological malignancies and a promising therapeutic potential in CTCL. Recent in vitro and in vivo data have shown that the combination of Resminostat (HDACi) with Ruxolitinib (Jaki) acts synergistically and inhibits tumorigenesis and metastasis in CTCL experimental models. Angiogenesis is the most critical process for tumor growth and metastasis and plays an essential role in cutaneous lymphoma development and progression. The vascular microenvironment of lymphomas accelerates angiogenesis via the paracrine activity of tumor-derived mediators. However, few studies have investigated the role of either ruxolitinib or resminostat in the angiogenesis of hematological malignancies and solid tumors. Although precise mechanisms of angiogenesis in CTCL remain unclear, the chick embryo chorioallantoic membrane (CAM) has been used, among other in vivo models, to implant several tumor types as well as malignant cell lines to study their growth rate, angiogenic potential, and metastatic capability. The aim of this study was to investigate the effects of combinational therapies of JAKi/HDACi in CTCL angiogenesis by using a CTCL-specific chick embryo model. Angiogenesis plays a pivotal role in the growth and metastasis of tumors, including the development and progression of cutaneous lymphomas. The chick embryo CAM model has been utilized in various studies to assess the growth rate, angiogenic potential, and metastatic capability of different tumor types and malignant cell lines. However, the precise mechanisms of angiogenesis in CTCL and the influence of Ruxolitinib or Resminostat on angiogenesis in hematological malignancies and solid tumors are not well understood. Recent in vitro and in vivo data have demonstrated the synergistic inhibition of tumorigenesis and metastasis in experimental models of CTCL when using the combination of Resminostat (HDACi) with Ruxolitinib (JAKi). The present work aims to elucidate the effects of this combination on the tumor microenvironment's vascular components. We investigated the effects of Ruxolitinib (JAKi) in combination with Resminostat (HDACi) treatment in transendothelial migration of CTCL cells (106 MyLa and SeAx) by using a transwell-based transendothelial migration assay and tumor angiogenesis in vivo. We used the CTCL chick embryo CAM model with xenografted tumors derived from implanted MyLa and SeAx cells and administered topically 15 μM ruxolitinib and 5 μM Resminostat every two days during a 5-day period. JAKi and HDACi inhibited CTCL cell transendothelial migration by 75% and 82% (p < 0.05) in both CTCL engrafted cells (MyLa and SeAx, respectively) compared to the untreated group. Moreover, the combination of ruxolitinib with resminostat blocked angiogenesis by significantly reducing the number of blood vessel formation by 49% and 34% in both MyLa and SeAx, respectively (p < 0.05), indicating that the proposed combination exerted significant anti-angiogenic effects in the CAM CTCL model. Overall, these data provide valuable insights into potential therapeutic strategies targeting angiogenesis in CTCL, paving the way for more effective treatment approaches in the future. [ABSTRACT FROM AUTHOR]