## 4 Discussion
(2021) reported that bioimpedance in a cell population is of a low frequency when electric currents do not penetrate cell membranes, resulting in measuring only water impedance [53]. They also proposed that the grade of hydration in the cells directly affects the polymerization of the cytoskeleton in living cells. In this context, changes in the actin fibers could be related to hydration [54]. [PERSON] and [PERSON] (2018) [55] documented that cell migration is a complex process orchestrated by actin dynamics, focal adhesions, and water flux. This agrees with our results, where actin fibers were rearranged and translated as changes when MSCs were cultivated in the presence of a tumoral secretome. Therefore, bioimpedance allows us to investigate the subtle changes that are not visible to the naked eye. We concluded that untreated cells respond differently to the external electric field. This is because they possess different electrical properties provided by membrane capacitance and cytosol resistance [36]. Since MSCs have not shown evidence of tumoral malignancy with the classic techniques used previously, bioimpedance spectroscopy only indicated changes related to the effect of the secretome; it probably changes the components in the membrane or cytoplasm, as well as the water contained as an adaptive response. Nevertheless, tumoral behavior could be reflected by specific bioimpedance spectra patterns (involving unique conditions of the capacitance and resistance of molecular expression) [40], although this was not found in our results. While protein profiling of the secretome was not performed, mRNA expression was evaluated via agarose gel electrophoresis in an effort to understand the cellular alterations. Specific markers, such as NANOG, OCT4, IL-10, TGF-\(\beta\), CD73, CD90, and CD105, were analyzed to identify the key biological responses. CD90 is a marker of MSCs; however, the overexpression of CD90 can indicate the tumor transformation of stem cells [56]. In this study, it does not appear that the changes in characteristics were related to tumor transformation, as CD90 decreased. Previous studies have demonstrated that CD90 decreases while other markers increase due to differentiation processes [57]. In this case, the migration processes might be related to the reduced CD90. Recently, it was reported by [PERSON] (2023) [58] that the downregulation of CD90 is associated with a decrease in the proliferation rate, which was also observed in this work. TGF-\(\beta\) and its receptors can be strongly induced in the presence of carcinogens that pretend to disrupt cell homeostasis to produce an oncogenic transformation [59]. Our results showed that the tumoral environment induced the high expression of TGF-\(\beta\) mRNA but did not influence cell proliferation. TGF-\(\beta\) is involved in malignant hepatocellular progression through interaction with CD105 [60]. While protein profiling of the secretome was not performed, mRNA expression was evaluated via agarose gel electrophoresis to confirm the biological activity. Our results indicate that CD105 expression did not change when cultures were exposed to a tumoral environment (Figure 10a). [PERSON] et al. (2017) [61] reported that in monkeys, when CD105 was exacerbated, cell migration occurred in response to damage induced by previously produced osteoarthritis. Therefore, the high expression of TGF-\(\beta\) mRNA seems to be involved in an inflammatory process occasioned by the tumoral medium in cell cultures since TGF-\(\beta\) promotes wound healing by participating in the inflammation step during the stage of proliferation and remodeling [59]. Evidently, the cytoskeletal changes shown in this work are related to this process of maintaining homeostasis under a tumoral environment. NANOG mRNA was not detected under any conditions. Various studies have proposed that downregulated NANOG is associated with decreased proliferation and migration. Furthermore, NANOG has been proposed as a predictor of poor prognosis in people with breast or kidney cancer [62].