Publications by authors named "Yan-Shi Guo"

Seventy-five years after its initial report, lifespan prolongation by caloric restriction (CR) has been confirmed in many animal species. Gathered evidences suggest that the histone deacetylase Sir2/SIRT1 is a key mediator. Moreover, resveratrol (RSV), a plant derived polyphenol, was shown to increase SIRT1 catalytic activity and mimics many aspects of CR in all eukaryotes tested.

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Induced pluripotent stem cells (iPSCs) can differentiate into mineralizing cells and thus have a great potential in application in engineered bone substitutes with bioactive scaffolds in regeneration medicine. In the current study we characterized and demonstrated the pluripotency and osteogenic differentiation of mouse iPSCs. To enhance the osteogenic differentiation of iPSCs, we then transduced the iPSCs with the potent transcription factor, nuclear matrix protein SATB2.

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Mammalian intestinal epithelium undergoes continuous cell turn over, with cell proliferation in the crypts and apoptosis in the villus. Both transforming growth factor (TGF)-beta and gastrin-releasing peptide (GRP) are involved in the regulation of intestinal epithelial cells for division, differentiation, adhesion, migration and death. Previously, we have shown that TGF-beta and bombesin (BBS) synergistically induce cyclooxygenase-2 (COX-2) expression and subsequent prostaglandin E(2) (PGE2) production through p38(MAPK) in rat intestinal epithelial cell line stably transfected with GRP receptor (RIE/GRPR), suggesting the interaction between TGF-beta signaling pathway and GRPR.

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Overexpression of cyclooxygenase-2 (COX-2), an inducible enzyme regulating prostaglandin release, is mechanistically linked to the development, growth, and spread of gastrointestinal (GI) cancers. GI peptide bombesin (BBS) was reported to stimulate COX-2 gene expression. Here we show that TGF-beta1 dramatically enhances the BBS-induced expression of COX-2 mRNA and protein, and the release of PGE2 in the model rat intestinal epithelial cell (RIE-1) line.

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The majority of deaths from prostate cancer occur in patients with androgen-insensitive metastatic disease. An important early event in the development of the metastatic phenotype is the induction of genes that promote angiogenesis, such as vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8), which are released from tumor cells into their microenvironment. Coincident with progression from prostatic carcinoma in situ to metastatic disease is an increase in the number of tumor cells exhibiting neuroendocrine (NE) differentiation.

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Gastrin is a hormone produced by G-cells in the normal gastric antrum. However, colorectal carcinoma cells may aberrantly produce gastrin and exhibit increased expression of cholecystokinin B (CCK-B)/gastrin receptors. Gastrin is trophic for the normal gastric oxyntic mucosa and exerts a growth-promoting action on gastrointestinal malignancy.

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The integrity of the retinal pigment epithelium, especially that of the macula is essential for the preservation of vision into old age. The chronic exposure to sunlight and peroxidized lipids from phagocytized photoreceptor outer segments imposes a high level of oxidative stress on the retinal tissues, which increases with age as antioxidant protection declines and therefore could accelerate apoptosis. Bcl-2 known to facilitate mitochondrial DNA repair and cellular survival in other tissues was overexpressed in a single clone of human retinal pigment epithelium cells after stable transfection with humanbcl-2 in rhoSFV-neoexpression factor.

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