Background/Objectives: Multiple myeloma (MM) is an incurable, hematological malignancy caused by the abnormal proliferation of terminally differentiated plasma cells in the bone marrow. Current research indicates that N-azacytidine, as an epigenetic drug and nucleoside metabolic inhibitor, can be efficient in MM treatment. However, data on bone marrow mesenchymal stromal cells (BMSCs), as a critical cell population in the hematopoiesis and bone remodeling processes, are limited. Methods: The effect of N-azacytidine on the myeloma cell line AMO-1, bone marrow mesenchymal stromal cells from MM patients (MM-MSCs) and patients undergoing hip arthroplasty (BMSCs) as a healthy control in hypoxia (3% O₂) were examined. Cellular functions such as viability, proliferation, phenotype, and differentiation were determined by in vitro tests and flow-cytometry. Results: N-azacytidine (100 nM to 1000 nM) significantly inhibited metabolic activity, cell cycle, CFSE dilution and CD138+/CD38+ expression levels by myeloma cells after 72 h. No viability changes were detected in MM-MSCs and BMSCs treated with N-azacytidine. As for both BMSCs and MM-MSCs differentiation potential, N-azacytidine did not affect alkaline phosphatase (ALP) activity and adipogenesis but inhibited matrix mineralization (500 nM and 1000 nM). However, when BMSCs were pretreated with N-azacytidine for 72 h, changes in ALP activity and mineralization level were not detected. Conclusions: N-azacytidine, along with the suppressive effect on myeloma cells, did not change the differentiation potential of MSCs, but rather preserved their capacity. These findings are of particular importance considering MM progression and bone tissue destruction, suggesting that N-azacytidine may represent a promising therapeutic agent for myeloma disease.

Human placenta-derived amniotic membrane (hAM) and its derivatives have attracted growing interest as bioactive materials for tissue engineering, regenerative medicine, and biomaterial design. This review summarizes the anatomical and cellular characteristics of hAM and examines the interplay between its regenerative and immunomodulatory properties. Key hAM-derived biomolecules are discussed, with an emphasis on their roles in immune regulation, angiogenesis, extracellular matrix remodeling, and tissue repair across diverse regenerative contexts. Current applications of hAM-based materials in tissue engineering and regenerative biomaterials are reviewed, including emerging studies involving soft tissue applications. In addition, recent efforts to integrate hAM derivatives into 3D bioprinting approaches are examined, including their use as bioink components or biofunctional additives to hydrogel-based systems. Although studies involving hAM-based bioprinted constructs remain limited, the available findings suggest promising regenerative, proangiogenic, and bioactive effects. Challenges related to material processing, printability, standardization, and reproducibility are also discussed. Overall, this review highlights the biomaterial potential of hAM derivatives and their emerging relevance to biofabrication strategies aimed at developing biologically instructive constructs for regenerative medicine.