Abstract
The placental stem cells have called the focus of attention for their therapeutic potential to treat different diseases, including cancer. There is plenty evidence about the antiproliferative, antiangiogenic and proapoptotic properties of the amniotic membrane. Liver cancer is the fifth cause of cancer in the world, with a poor prognosis and survival. Alternative treatments to radio- or chemotherapy have been searched. In this work we aimed to study the antiproliferative properties of the human amniotic membrane conditioned medium (AM-CM) in hepatocarcinoma cells. In addition, we have analyzed the regulation of pro and antiOncomiRs expression involved in hepatocarcinoma physiology. We have determined by 3H-thymidine incorporation assay that AM-CM inhibits DNA synthesis in HepG2 cells after 72 h of treatment. AM-CM pure or diluted at 50% and 25% also diminished HepG2 and HuH-7 cells viability and cell number. Furthermore, AM-CM induced cell cycle arrest in G2/M. When proliferation mechanisms were analyzed we found that AM-CM reduced the expression of both Cyclin D1 mRNA and protein. Nuclear expression of Ki-67 was also reduced. We observed that this CM was able to promote the expression of p53 and p21 mRNA and proteins, leading to cell growth arrest. Moreover, AM-CM induced an increase in nuclear p21 localization, observed by immunofluorescence. As p53 levels were increased, Mdm-2 expression was downregulated. Interestingly, HepG2 and HuH-7 cells treatment with AM-CM during 24 and 72 h produced an upregulation of antiOncomiRs 15a and 210, and a downregulation of proOncomiRs 206 and 145. We provide new evidence about the promising novel applications of human amniotic membrane in liver cancer.
Highlights
Human amniotic membrane is well known for many of its beneficial properties and its promising applications
Despite amniotic membrane conditioned medium (AM-conditioned medium (CM)) produced a significant decrease in HuH-7 cell viability, it was minor than the obtained for HepG2 cells (Fig. 1C)
We have demonstrated that AM-CM significantly inhibits DNA synthesis in hepatocarcinoma HepG2 cells after 24 and 72 h of treatment, compared with serum deprived control
Summary
Human amniotic membrane (hAM) is well known for many of its beneficial properties and its promising applications. Amniotic epithelial (hAECs) or mesenchymal cells (hAMCS) secrete a large amount of antiangiogenic factors like interleukin-1 receptor antagonist, collagen XVIII, IL-10, thrombospondin-1 and tissue inhibitor of metalloprotease (TIMP-1, -2, -3, and -4)[13] As well, they have been described to express the pigment epithelium-derived factor (PEDF), which is known to inhibit proliferation of endothelial cells, contributing to hAM antiangiogenic activity[14]. Studies in vivo revealed that hAMPEs were able to promote a complete tumor regression in mice inoculated with HepG2 but not with HuH-7 cells These authors demonstrated that hAMPEs negatively regulate protein and DNA content in all HCC lines[33]. Mamede et al concluded that hAMPE was capable of induce cell death through intrinsic or extrinsic pathways, depending on the treated hepatocarcinoma cell line[33]
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