固体肿瘤中常见的一种细胞应激物是血清和生长因子缺乏，这种应激物可通过放射治疗、化疗和抗血管生成来产生。球体体培养旨在通过使用低附着条件和一些生长因子（例如碱性成纤维细胞生长因子和表皮生长因子）富集癌干细胞，以支持无血清球体培养中的球体形成。然而，无生长因子的球体培养可以更真实地模拟肿瘤环境。在本研究中，我们旨在以干细胞特性为指标，探究生长因子缺乏对MKN-45胃癌细胞系的影响。通过在低附着条件下培养MKN-45胃癌细胞来获取球体，然后解离球体以获得细胞进行进一步分析。利用肿瘤球体形成试验、软琼脂分化试验、Transwell侵袭试验、化疗敏感性试验和定量RT-PCR试验分析了自我更新、多向分化、细胞转化、侵袭能力、化疗耐药性和干细胞相关基因的表达。胎牛血清和生长因子缺乏会导致OCT4、NANOG、SOX2、MUC1、CD24和CD90等干细胞标记物的增加。在无胎牛血清-生长因子的条件下，也观察到自我更新、化疗耐药性和侵袭能力等功能依赖特征的增加。生长因子可能不是富集癌干细胞的球体培养的必需品。缺乏胎牛血清和生长因子也会诱导MKN-45细胞表现出更具侵袭性的表型，因此为进一步研究靶向肿瘤细胞提供了机会。© TÜBİTAK.

Serum and growth factor deprivation, a common cellular stressor in solid tumors, arises upon irradiation, chemotherapy, and antiangiogenesis. Spheroid body culture aims to enrich cancer stem cells by using low attachment conditions and some growth factors, such as basic fibroblast growth factor and epidermal growth factor to support the spheroid formation in serum-free spheroid culture. However, spheroid culture without any growth factors can imitate the tumor environment more realistically.In this study, we aimed to identify the effect of growth factor deprivation on the MKN-45 gastric cancer cell line in terms of stemness characteristics.The spheroids were obtained by culturing MKN-45 gastric cancer cells in low attachment conditions, and then spheroids were dissociated to obtain cells for further analyses. Self-renewal, multipotency, cellular transformation, invasiveness, chemoresistance, and the expression of stemness-related genes were analyzed using tumor spheroid formation assay, soft agar colony formation assay, transwell invasion assay, chemosensitivity assay, and quantitative RT-PCR assay, respectively.Fetal bovine serum and growth factor deprivation caused an increase in stemness markers of OCT4, NANOG, SOX2, MUC1, CD24 and CD90. Increasing functional aggressiveness-related properties, such as self-renewal, chemoresistance, and invasive ability, have also been observed in fetal bovine serum-growth factor-free conditions.Growth factors may not be essential for spheroid culture to enrich cancer stem cells. The deprivation of both fetal bovine serum and growth factors also induces a more aggressive phenotype in MKN-45 cells; thus, it provides an opportunity for further studies targeting tumor cells.© TÜBİTAK.