Role of HGF/c-met system in invasion and metastasis of oral squamous cell carcinoma cellsin vitro and its clinical significance

Abstract

We examined the role of the hepatocyte growth factor (HGF)/c-met system on invasion and metastasis of oral squamous cell carcinoma (SCC) cells. In monolayer culture, exogenous HGF marginally affected the growth of oral SCC cells (BHY, HN, IH) and human gingival epithelial cells (GE). In type I collagen matrix, however, HGF significantly enhanced the invasive growth of the cancer cells (p < 0.05). We detected the expression of c-met (HGF receptor) mRNA in all of the cancer cells, but not in human gingival fibroblasts (GF). Oral SCC cells did not secret HGF protein into the medium, but GF secreted a large amount of HGF protein (15 ng/ml). Furthermore, HGF markedly enhanced the migration of cancer cells in a Transwell invasion chamber. Then, we examined the serum levels of HGF in oral SCC patients, or HGF concentrations in oral cancer tissues. Serum levels of HGF in the patients were significantly higher than those in healthy volunteers (p < 0.05). After initial treatment, all of the tumor-free survivors showed a marked decline in the serum HGF levels. Furthermore, HGF concentrations in metastatic cancer tissues were significantly higher than those of nonmetastatic cancer tissues and normal gingiva (p < 0.01). These results suggest that HGF plays an important role in invasion and metastasis of oral SCC cells as a paracrine factor, and an elevated HGF level in the cancer tissue can be a predictive marker for metastasis formation in patients with oral SCC. © 2001 Wiley-Liss, Inc. Key words: oral SCC; HGF; c-met; metastasisOral SCCs are characterized by a high degree of local invasion and a high rate of metastases to cervical lymph nodes, but a low rate of metastases to distant organs. Moreover, oral SCC frequently show local recurrence after initial treatment, probably due to micro-invasion or micro-metastasis of the tumor cells at the primary site. We recently reported that oral SCC cells produced a large amount of matrix-degrading enzymes and that the net activity of MMP2 (active-MMP2/TIMP2) produced by cancer cells contributes to lymph-node metastasis in a nude-mouse orthotopic inoculation model. 1 We also noted that cancer cells in the peripheral blood of patients with oral SCC were frequently detected by RT-PCR for cytokeratin 20 mRNA, and that there was no clear relationship between the hematogenous cancer cells and the metastasis. 2 Furthermore, by microdissection zymography, we demonstrated that active MMP2 in cancer cell nests could be a predictive marker for metastasis formation in patients with oral SCC. 3 The precise molecular mechanisms of invasion and metastasis of oral cancer, however, especially the interaction between cancer cells and host cells, are still unknown.

Regulation of microRNA expression by hepatocyte growth factor in human head and neck squamous cell carcinoma

“…(4)(5)(6) It is also known to be a scatter factor (SF) (4) and involved in tumor-stromal interactions and EMT. (25,26) MET, a specific receptor tyrosine kinase for HGF ⁄ SF, is upregulated in various tumors including human HNSCC and its signal transduction induces progression and invasiveness of HNSCC in a paracrine or autocrine manner.…”

“…(25,26) MET, a specific receptor tyrosine kinase for HGF ⁄ SF, is upregulated in various tumors including human HNSCC and its signal transduction induces progression and invasiveness of HNSCC in a paracrine or autocrine manner. (5)(6)(7) Indeed, it has been reported that HGF ⁄ SF promotes cell migration and angiogenesis in human esophageal SCC, (27) upregulates the expression of proangiogenic cytokines interleukin (IL)-8 and vascular endothelial growth factor (VEGF) through the activation of mitogen-activated protein ⁄ extracellular signal-regulated kinase kinase (MEK) and phosphatidylinositol 3¢-kinase (PI3K) signaling pathways in HNSCC, (28) and induces the invasion of oral SCC by matrix metalloproteinase genes through the upregulation of the transcription factor E1AF. (29) However, how HGF ⁄ SF and MET signaling cascade affects the expression of each specific downstream functional gene has not yet been elucidated in detail.…”

“…(2) One of these factors, hepatocyte growth factor (HGF), is a multifunctional growth factor that acts as mitogen, motogen and ⁄ or morphogen in a variety of cells including squamous epithelial cells. (4)(5)(6) MET, a specific receptor tyrosine kinase for HGF, is upregulated in various tumors including human HNSCC, and its signal transduction to the nucleus induces the expression of genes involving the progressive and invasive characteristics of HNSCC. (5)(6)(7) However, how HGF affects downstream functional gene expression has not yet been elucidated in detail.…”

Tumour-derived TGF-β1 modulates myofibroblast differentiation and promotes HGF/SF-dependent invasion of squamous carcinoma cells

“…This results in disruption of intercellular junctions, dissolution of epithelial basement membrane and altered integrin interactions with extracellular matrix (Trusolino and Comoglio, 2002). Fibroblast-derived HGF/SF has been shown to stimulate invasion and migration in a number of tumour types including squamous cell carcinoma (Matsumoto et al, 1994;Uchida et al, 2001), and we have demonstrated previously that exogenous HGF/SF induces expression of the type IV collagenases MMP-2 and -9 in squamous carcinoma cells (Bennett et al, 2000). The latter observation suggests a possible mechanism for the HGF/SF-dependent invasion through basement membrane-like Matrigel (which comprises predominantly type IV collagen) described in this study.…”

Metastatic squamous cell carcinoma cells that overexpress c-Met exhibit enhanced angiogenesis factor expression, scattering and metastasis in response to hepatocyte growth factor

“…Yu et al recently showed that a nonautocrine interaction between HGF transgenic hosts and c-Met expressing melanoma cells significantly promotes tumor metastasis in vivo (Yu and Merlino, 2002). Clinically, elevated serum HGF levels have been found in patients with cancers from bladder, breast, colon, gastric, liver, lung and head and neck (Takigawa et al, 1997;Taniguchi et al, 1997;Fukuura et al, 1998;Toi et al, 1998;Junbo et al, 1999;Gohji et al, 2000;Naughton et al, 2001;Uchida et al, 2001, Dong, 2001b. Significantly, this elevated serum HGF is associated with poor prognosis.…”