ABSTRACT
Progastrin is an unprocessed soluble peptide precursor with a well-described tumor-promoting role in colorectal cancer. It is expressed at small levels in the healthy intestinal mucosa, and its expression is enhanced at early stages of intestinal tumor development, with high levels of this peptide in hyperplastic intestinal polyps being associated with poor neoplasm-free survival in patients. Yet, the precise type of progastrin-producing cells in the healthy intestinal mucosa and in early adenomas remains unclear. Here, we used a combination of immunostaining, RNAscope labelling and retrospective analysis of single cell RNAseq results to demonstrate that progastrin is produced within intestinal crypts by a subset of Bmi1+/Prox1+/LGR5low endocrine cells, previously shown to act as replacement stem cells in case of mucosal injury. In contrast, our findings indicate that intestinal stem cells, specified by expression of the Wnt signaling target LGR5, become the main source of progastrin production in early mouse and human intestinal adenomas. Collectively our results suggest that the previously identified feed-forward mechanisms between progastrin and Wnt signaling is a hallmark of early neoplastic transformation in mouse and human colonic adenomas.
ABSTRACT
Hepatocellular carcinoma (HCC) is one of the most common malignancies and the fifth leading cause of cancer-related death worldwide. Novel prognostic biomarkers are urgently needed for patients with HCC. Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) overexpression may promote tumor metastasis in HCC. However, few studies investigate the prognosis predictive role of LGR5 in patients with HCC. Herein, we aimed to examine the expression level of LGR5 in tumors and its correlation with clinical characteristics and survivals of patients with HCC. LGR5 expression in tumor specimens and adjacent tissue resected from 66 patients were detected by immunohistochemistry. The results showed that the expression of LGR5 was markedly higher in HCC than in normal adjacent tissues (Pâ¯=â¯.006). High expression of LGR5 was significantly correlated with later disease stage (Pâ¯=â¯.009). In addition, high LGR5 expression was remarkably correlated with short overall survival than those with low LGR5 expression (Pâ¯<â¯.05). The median overall survival of patients with high LGR5 expression was 12â¯months, whereas that of patients with low LGR5 expression was still not reached (longer than 70â¯months). Notably, in our limited cases, we did not detect any difference in tumor size, lymphatic invasion, or metastasis in patients with high or low expression of LGR5. In conclusion, high protein level of LGR5 was associated with poor prognosis of these patients. LGR5 appears to be a valuable prognostic predictor clinically and a potential target in HCC therapy.
ABSTRACT
Objective To investigate the clinical significance and biological role of G-protein coupled receptor 49(GPR49) expression in pancreatic carcinoma.Methods GPR49 expression in tumor and adjacent normal tissues of 77 patients with pancreatic cancer was compared by tissue microarray and immunohistochemistry.And then, the GPR49 expression levels in the tumor tissues of patients with different pathological grades and clinical stages were analyzed.GPR49 positive pancreatic cancer cell line CFPAC-1 was taken as cellular model.CFPAC-1 cells were stimulated with roof plate-specific spondin(RSPO)1, the ligand of GPR49, in vitro.The effect of RSPO1 on CFPAC-1 cells proliferation was evaluated with cell counting.The effect of RSPO1 on the expression of membrane molecular CD44 in CFPAC-1 cells was detected by flow cytometry.CFPAC-1 cells incubated with RSPO1 were subcutaneously implanted into nude mice.And then, the time of tumor formation and tumor size were observed.T test and single factor analysis of variance were performed for statistical analysis.Results GPR49 was widely expressed in all 77 pancreatic cancer tissues.By immunohistochemistry, the score of GPR49 expression in pancreatic cancer tissues was 9.0±2.4, which was higher than that of adjacent normal tissues (5.7±2.4), and the difference was statistically significant (t=8.995, P0.05).The results of experiments in vitro indicated that RSPO1 could promote CFPAC-1 cells proliferation and up-regulate CD44 expression in CFPAC-1 cells.Experiments in vivo demonstrated that after 30 days the tumor volume of mice implanted with RSPO1-pretreated CFPAC-1 cells was (606.0±188.0) mm3, which was larger than that of PBS-pretreated group ((364.2±83.7) mm3), and the difference was statistically significant (t=2.616, P=0.031).Conclusion GPR49 is widely expressed in pancreatic cancer cells and RSPO1/GPR49 pathway has play a role in promoting the proliferation of pancreatic cancer cells, which might be a potential target for interfering pancreatic cancer.
ABSTRACT
The biological roles of stem cell marker LGR5, the receptor for the Wnt-agonistic R-spondins, for nervous system are poorly known. Bioinformatics analysis in normal human brain tissues revealed that LGR5 is closely related with neuron development and functions. Interestingly, LGR5 and its ligands R-spondins (RSPO2 and RSPO3) are specifically highly expressed in projection motor neurons in the spinal cord, brain stem and cerebral. Inhibition of Notch activity in neural stem cells (NSCs) increased the percentage of neuronal cells and promoted LGR5 expression, while activation of Notch signal decreased neuronal cells and inhibited the LGR5 expression. Furthermore, knockdown of LGR5 inhibited the expression of neuronal markers MAP2, NeuN, GAP43, SYP and CHRM3, and also reduced the expression of genes that program the identity of motor neurons, including Isl1, Lhx3, PHOX2A, TBX20 and NEUROG2. Our data demonstrated that LGR5 is highly expressed in motor neurons in nervous system and is involved in their development by regulating transcription factors that program motor neuron identity.
