RAGE activation by S100P in colon cancer stimulates growth, migration, and cell signaling pathways.

PURPOSE: Colon cancer is the third most prevalent cancer in the United States. However, the molecular mechanisms involved in the development and progression of colon cancer are incompletely understood. This study was initiated to explore the potential role of the receptor for advanced glycation end-products and S100P in modulation of key properties of human colon cancer cells. METHODS: Western blot, reverse transcription-polymerase chain reaction, and quantitative polymerase chain reaction were performed for detection of the receptor for advanced glycation end-products and S100P in colon cancer and matched normal colon. The influence of exogenously added S100P was analyzed on SW480 colon cancer cell line proliferation, migration, phosphorylation of mitogen activated protein kinases, and NFkappaB activation. To identify the mechanisms involved in these responses, coimmunoprecipitation examining the S100P/Receptor for advanced glycation end-products interaction and the effects of receptor for advanced glycation end-products inhibition in this interaction were analyzed. RESULTS: Although the receptor for advanced glycation end-products was present in normal and malignant colon specimens, only the malignant specimens expressed S100P. Treatment of SW480 cells with S100P increased proliferation and cell migration. Addition of exogenous S100P stimulated both ERK1/2 phosphorylation and NFkappaB activity. The interaction between S100P and the receptor for advanced glycation end-products was demonstrated by coimmunoprecipitation of these molecules from SW480 cells. Antagonism of the receptor for advanced glycation end-products blocked this interaction and the biologic effects of S100P on these cells. CONCLUSIONS: These data indicate that S100P is expressed at greater levels in colon cancer than matched normal tissue and that S100P stimulates colon cancer cell growth, migration, Erk phosphorylation, and NFkappaB activation in vitro, suggesting that this ligand/receptor pair may be targeted for the development of new therapies.

Induction of inflammatory bowel disease accelerates adenoma formation in Min +/- mice.

BACKGROUND: The accelerated incidence of colorectal carcinoma in individuals with inflammatory bowel disease suggests that cellular perturbation triggered by chronic inflammation is linked to the development of dysplasia and neoplastic transformation. To test the mechanistic links between these processes, we employed the following murine strains: (1) multiple intestinal neoplasia (Min) +/- mice, bearing a mutation in the adenomatous polyposis coli (APC) gene; (2) mice deficient in interleukin 10 (IL-10), which normally develop enterocolitis; and (3) Min +/-/IL-10 null mice, first developed in our laboratory. METHODS: Mice with either parental strain or the cross were sacrificed at time points ranging from 10 to 30 weeks of age. The small bowel and colon of 170 IL-10 null mice, 31 Min +/- mice, and 120 Min +/-/IL-10 null mice were examined microscopically. RESULTS: The number of flat adenomas was increased in the colons of the Min +/-/IL-10-/- mice, compared with the Min +/- mice (P = .0005). Neither colitis-type dysplasia nor carcinoma was increased in the Min +/-/IL-10 -/-, compared with the IL-10 null mice (P = .18). Mice deficient in IL-10 developed colitic-type dysplasia (P = .0001) or carcinoma (P = .0001) correlated with increasing inflammation. CONCLUSIONS: Breeding the Min +/- genotype into the IL-10 -/- background increased the incidence of colonic adenomas. Our studies demonstrate that acceleration of dysplasia and progression to invasion were associated with the degree of the inflammatory response in mice deficient in IL-10. These findings provide a novel system to dissect the pathways by which inflammatory mechanisms accelerate adenoma formation.

Lentiviral gene therapy with platelet-derived growth factor B sustains accelerated healing of diabetic wounds over time.

The treatment of diabetic wounds is a formidable clinical challenge. In this study, lentiviral vectors carrying the human platelet-derived growth factor B (PDGF-B) gene were used to treated diabetic mouse wounds. Full-thickness 2.0-cm x 2.0-cm excisional wounds were created on the dorsa of genetically diabetic C57BL/KsJ-m+/+Lepr(db) mice. Lentiviral vectors containing the PDGF-B gene were injected into the wound margins and base. Mice were killed at 14-, 21-, and 35-day intervals. Measurement of the residual epithelial gap showed a trend towards increased healing in lentiviral PDGF-treated wounds compared with untreated and saline-treated wounds at all time points. At 21 days, there was significantly increased healing in lentiviral PDGF-treated wounds (0.98+/-0.17 cm) compared with saline-treated wounds (1.22+/-0.30 cm; P<0.05). Immunohistochemistry for CD31 revealed significantly increased neovascularization in lentiviral PDGF-treated wounds compared with untreated and saline-treated wounds at 14 and 21 days (P<0.01). Picrosirius red staining demonstrated thicker and more highly organized collagen fibers in treated wounds compared with untreated and saline-treated wounds. Quantitative analysis of collagen content showed a 3.5-fold and 2.3-fold increase in lentiviral PDGF-treated wounds versus untreated and saline-treated wounds, respectively (P<0.01). Lentiviral gene therapy with PDGF-B can sustain diabetic wound healing over time and may possess promising potential in the clinical setting.