Kiss-1 and its receptor (Kiss-1R) are suggested as a novel pair of metastasis suppressors for several human solid tumours. However, the role of Kiss-1 and Kiss-1R in colorectal cancer remains largely unknown. Therefore, the aim of this study was to investigate the role and signal transduction of Kiss-1 and its receptor in colorectal cancer. Colorectal cancer cell lines (HT115, HRT18, RKO and Caco-2) were screened for the mRNA expression levels of Kiss-1 and Kiss-1R. Sublines of cancer cells with differential expression of Kiss-1 and Kiss-1R were created, using ribozyme transgenes to knock down the expression of Kiss-1 and Kiss-1R, respectively. The stabilized transfected cells were used to study the influence of Kiss-1 and Kiss-1R on the function of colorectal cancer cells using by in vitro function assays (growth, adhesion, wounding and invasion assays) and ECIS assay. The influence of Kiss-1 on tumour growth was also tested using an in vivo tumour model. To further explore the receptor activation and signalling pathways downstream of Kiss-1, Kisspeptin-10 was also used in HT115 Kiss-1 knockdown cells. Phosphorylation of Kiss-1 and the effect of Kissthe effect on MMP 1 on MMP 1 on MMP-9 and MMP and MMP -2 were detected using immunoprecipitation and immunoprecipitation and zymographyzymography respectively. The study also investigated Kiss-1 and Kiss-1R expression and their correlation to the clinical outcome in human colorectal cancer, using real-time PCR and immunohistochemistry. Kiss-1 and Kiss-1R played a suppressive role in the invasion and migration of colorectal cancer cells, in that knocking down both Kiss-1 resulted in increased cell-matrix invasion and cellular migration as demonstrated by a series of cell models. Exogenous Kiss-1 (Kisspeptin-10) decreased cellular migration of colorectal cancer cells and required ERK signalling as shown during the ECIS based analyses. The inhibitory influence of Kiss-1 on the motility of cancer cells was via the reduction of MMP-9, shown by zymography. In the in vivo tumour model, tumour growth rate of Kiss-1 knockdown colorectal cancer cells was significantly faster than the control cells. In human colorectal cancer tissues, levels of message expression of Kiss-1 had a negative correlation with Dukes staging, TNM staging, tumour size and lymph node involvement. Kiss -1R expression was significantly decreased in tumour tissues compared with adjacent normal tissues. The present study has demonstrated that Kiss-1 and Kiss-1R play a pivotal tumour suppressor role in colorectal cancer. The inhibitory effect on cancer cells involves the regulation of MMPs and the ERK signaling pathway. The molecule pair is candidate prognostic indicator in patients with colorectal cancer.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:577906 |
| Date | January 2013 |
| Creators | Ji, Ke |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/49221/ |
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