Progression of familial adenomatous polyposis (FAP) colonic cells after transfer of the src or polyoma middle T oncogenes: cooperation between src and HGF/Met in invasion

Abstract

Summary Little is known about the the signalling pathways driving the adenoma-to-carcinoma sequence in human colonic epithelial cells. Accumulation and activation of the src tyrosine kinase in colon cancer suggest a potential role of this oncogene in this early progression. Therefore, we introduced either activated src (m-src), polyoma-MT alone or combined with normal c-src in the adenoma PC/AA/C1 cell line (PC) to define the function and phenotypic transformations induced by these oncogenes in familial adenomatous polyposis (FAP) colonic epithelial cells. Functional expression of these oncoproteins induced the adenoma-to-carcinoma conversion, overexpression of the hepatocyte growth factor (HGF) receptor Met, but failed to confer invasiveness in vivo and in vitro, or to produce alterations in cell proliferation and differentiation. In contrast, PC-msrc cells became susceptible to the HGF-induced invasion of collagen gels and exhibited sustained activation of the pp6osrctyrosine kinase and Tyr phosphorylation of the 120-kDa E-cadherin, which was further increased by HGF Transcripts of HGF were clearly identified by reverse transcription -polymerase chain reaction (RT-PCR) and Southern blot in the parental and transformed PC cells, suggesting an autocrine mechanism. Taken together, the data indicate that: (1) experimental activation of src and PyMT pathways directly induces tumorigenicity and Met upregulation in a colon adenoma cell line; (2) HGF-activated Met and src cooperate in inducing invasion; (3) in view of the molecular associations between catenins and cadherin or the tumour-suppressor gene product APC, the cell adhesion molecule E-cadherin may constitute a downstream effector of src and Met.

Induction of the adenoma-carcinoma progression and Cdc25A-B phosphatases by the trefoil factor TFF1 in human colon epithelial cells

“…Ectopic expression of TFF1 confers anchorageindependent growth and constitutive invasive phenotypes Consistent with their origin, we have previously shown that the premalignant adenomatous colon epithelial cells PC are not tumorigenic in the nude mice and are not spontaneously invasive in collagen type I gels (Empereur et al, 1997). Interestingly, forced expression of TFF1 in PC cells is associated with the induction of the invasive phenotype ( Figure 2a, left panel).…”

“…Human adenomatous PC colon cells and MCF-7 breast cancer cells were cultured in DMEM supplemented with 10-20% foetal bovine serum (Empereur et al, 1997). HCT8/S11 colon cancer cells were cultured in RPMI-1640 containing 10% FCS (Rodrigues et al, 2001).…”

Bile acids stimulate invasion and haptotaxis in human colorectal cancer cells through activation of multiple oncogenic signaling pathways

“…Similar negative results were obtained with CDCA, LCA and UDCA in the nontumorigenic kidney epithelial MDCKT23 cell line ( Figure 1). Next, we examined the possible cooperation between BA and SRC in the acquisition of the invasive phenotype using PCmsrc cells which were obtained after transfection of PC/AA/C1 cells by an expression vector encoding the activated form of the SRC oncogene (Empereur et al, 1997). As shown in Figure 1, CDCA and LCA, but not UDCA, stimulated the invasiveness of PCmsrc cells in collagen type I gels.…”

“…The PC/AA/C1 cell line is derived from an adenoma in a patient with familial adenomatous polyposis coli (FAP) (Williams et al, 1990). The PCmsrc cell line was established after stable transfection of PC/AA/C1 cells by an expression vector encoding the activated (Tyr527?Phe527) form of the SRC oncogene (Empereur et al, 1997). The PC/AA/C1 and PCmsrc cell lines were cultured in Dulbecco's Modified Eagle Medium (DMEM, Life Technologies) supplemented with 20% FBS, 8 mM L-glutamine, 100 mg/ml streptomycin, 250 IU/ml penicillin, 2.5 mg/ml fungizone, 1.75 mmol/l insulin and 1 mg/ml hydrocortisone.…”

“…Invasion and metastasis, the hallmarks of malignant tumors, are both greatly influenced by autocrine, paracrine and endocrine factors in the tumor (Mareel et al, 1996). Accordingly, invasion of colorectal cancer cells into collagen type I is induced by endogenous factors, such as hepatocyte growth factor (HGF), leptin and trefoil peptides (Empereur et al, 1997;Kotelevets et al, 1998;Attoub et al, 2000;Emami et al, 2001). The possible implication of BA in cancer cell invasion is suggested by the correlation between Dukes' stage of human colon tumors, and abnormal fecal deoxycholic acid (DCA)/ cholic acid (CA) and LCA/DCA concentration ratios, as well as the number of the BA binding sites in tumor cells (Summerton et al, 1983;Owen, 1997;Kamano et al, 1999).…”