Bone morphogenetic protein‐9 induces epithelial to mesenchymal transition in hepatocellular carcinoma cells

Abstract

Epithelial-mesenchymal transition (EMT) is an important mechanism to initiate cancer invasion and metastasis. Bone morphogenetic protein (BMP)-9 is a member of the transforming growth factor (TGF)-b superfamily. It has been suggested to play a role in cancer development in some non-hepatic tumors. In the present study, two hepatocellular carcinoma (HCC) lines, HLE and HepG2, were treated with BMP-9 in vitro, and phenotypic changes and cell motility were analyzed. In situ hybridization (ISH) and immunohistochemical analyses were performed with human HCC tissue samples in order to assess expression levels of BMP-9. In vivo, BMP-9 protein and mRNA were expressed in all the tested patients to diverse degrees. At the protein level, mildly positive (1 + ) BMP-9 staining could be observed in 25 ⁄ 41 (61%), and moderately to strongly positive (2 + ) in 16 ⁄ 41 (39%) of the patients. In 27 ⁄ 41 (65%) patients, the BMP-9 protein expression level was consistent with the mRNA expression level as measured by ISH. In those patients with 2 + protein level, nuclear pSmad1 expression in cancer cells was also significantly increased. Expression of BMP-9 was positively related to nuclear Snail expression and reversely correlated to cell surface E-cadherin expression, although this did not reach statistical significance. Expression levels of BMP-9 were significantly associated with the T stages of the investigated tumors and high levels of BMP-9 were detected by immunofluorescence especially at the tumor borders in samples from an HCC mouse model. In vitro, BMP-9 treatment caused a reduction of E-cadherin and ZO-1 and an induction of Vimentin and Snail expression. Furthermore, cell migration was enhanced by BMP-9 in both HCC cell lines. These results imply that EMT induced by BMP-9 is related to invasiveness of HCC. (Cancer Sci 2013; 104: 398-408) E ighty to ninety percent of primary liver cancer cases originate from hepatocellular carcinoma (HCC), which has been regarded as the fifth most common cancer and the third most cancer-related death in the world.(1) Current therapeutic options including surgical resection, liver transplantation and chemoembolization are only used at early stages of HCC with limited efficacy.(2) Cancer recurrence occurs in around 50% of patients.(3,4) Despite extensive scientific efforts, the prognosis of HCC is nowadays still poor since HCC is inclined to tumor invasiveness and formation of intra-and extra-hepatic metastases.Epithelial-mesenchymal transition (EMT) is one major mechanism participating in malignant progression of cancer cells. Epithelial-mesenchymal transition is characterized by loss of differentiated traits in epithelial cells, for example, cell-cell contacts and cell polarity, as well as acquisition of mesenchymal appearances such as higher motility, invasiveness and resistance to apoptosis.(5) Properties typical for EMT comprise downregulation of epithelial markers like E-cadherin, ZO-1, nuclear translocation of b-catenin and upregulation of mesenchymal markers like Vimentin, N-cadh...

BMP9 and BMP10 are necessary for proper closure of the ductus arteriosus

“…BMPs have been described as either inhibitors of endMT (BMP7 in cardiac fibrosis) (26) or inducers of endMT [BMP6 in cerebral cavernous malformations (27) and BMP2 in cardiac valve formation (28)]. BMP9 has been recently shown to induce EMT in hepatocellular carcinoma cells (29), and our data support that BMP9 and BMP10 can also induce endMT.…”

Enhanced expression of BMP6 inhibits hepatic fibrosis in non-alcoholic fatty liver disease

“…In line with this, we confirmed enhanced BMP4 expression and its correlation with aggressive tumour growth in human HCC tissues 4. Most recently, Li et al 5 identified that enhanced BMP9 expression induces epithelial to mesenchymal transition and herewith invasiveness of HCC cells in vitro . Besides HCC, Nakatsuka et al 6 reported transient expression of BMP2 and BMP4 in acute liver injury.…”

Transcriptome profiling reveals novel gene expression signatures and regulating transcription factors of TGFβ‐induced epithelial‐to‐mesenchymal transition

“…These proteins have been related to EMT regulation and cellular differentiation 22, 23, 24, 25. Nt2 was centered on NFkB and involved genes such as NFkB early‐response gene IER3, secreted signaling molecules bone morphogenetic protein (BMP), and TF ETS homologous factor (EHT) that belongs to an ETS TF subfamily characterized by epithelial‐specific expression and which may be involved in epithelial differentiation and carcinogenesis 26, 27, 28, 29. Nt3 was closely related to cancer and cellular movement being involved with the WNT pathway and ‘cadherin switch’ (repression of E‐cadherin and expression of N‐cadherin).…”