Zongyu Zhang

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Sir2, a NAD-dependent deacetylase, modulates lifespan in yeasts, worms and flies. The SIRT1, mammalian homologue of Sir2, regulates signaling for favoring survival in stress. But whether SIRT1 has the function to influence cell viability and senescence under non-stressed conditions in human diploid fibroblasts is far from unknown. Our data showed that(More)
H2O2 has been the most commonly used inducer for stress-induced premature senescence (SIPS), which shares features of replicative senescence. However, there is still uncertainty whether SIPS and replicative senescence differ or utilize different pathways. 'Young' human diploid fibroblasts (HDFs), treated with prolonged low doses of hydrogen peroxide, led to(More)
Astragalus membranceus (Fish) Bunge Var. mongholicus (Bge) Hsiao is a Chinese herb considered as an effective traditional anti-ageing material. The two isomers of 4-hydroxy-5-hydroxymethyl-[1,3]dioxolan-2,6'-spirane-5',6',7',8'-tetrahydro-indolizine-3'-carbaldehyde (HDTIC), HDTIC-1 and HDTIC-2, were extracted from the herb. We chose them to investigate(More)
Using a suppressive subtractive hybridization system, we identified CSIG (cellular senescence-inhibited gene protein; RSL1D1) that was abundant in young human diploid fibroblast cells but declined upon replicative senescence. Overexpression or knockdown of CSIG did not influence p21(Cip1) and p16(INK4a) expressions. Instead, CSIG negatively regulated PTEN(More)
Peroxisome proliferator-activated receptor gamma (PPARgamma) plays an important role in the inhibition of cell growth by promoting cell-cycle arrest, and PPARgamma activation induces the expression of p16(INK4alpha) (CDKN2A), an important cell-cycle inhibitor that can induce senescence. However, the role of PPARgamma in cellular senescence is unknown. Here,(More)
Id1, a member of Id family of helix-loop-helix transcriptional regulatory proteins, is implicated in cellular senescence by repressing p16(INK4a) expression, but the mechanisms and cellular effects in human diploid fibroblasts remain unknown. Here we analyzed the patterns of p16(INK4a) and Id1 expression during the lifespan of 2BS cells and presented the(More)
Cellular senescence is a well-established model system for studying the molecular basis of aging. To identify a reliable biomarker for cellular age and further study the gene expression of aging, we profiled the gene expression difference between aged and young cultured human embryonic lung fibroblasts by high-density complementary deoxyribonucleic acid(More)
BACKGROUND p16(INK4a) tumor suppressor protein has been widely proposed to mediate entrance of the cells into the senescent stage. Promoter of p16(INK4a) gene contains at least five putative GC boxes, named GC-I to V, respectively. Our previous data showed that a potential Sp1 binding site, within the promoter region from -466 to -451, acts as a positive(More)
p16INK4a, a cell cycle inhibitor that inhibits cyclin-dependent kinase 4 (cdk4) and cdk6, has been found as the tumor suppressor gene and is frequently deleted, methylated or mutated in many malignancies. Since p16INK4a is also a key element controlling cellular senescence and other functions, we hypothesized that p16INK4a induced tumor suppression may not(More)
Cellular senescence marks the end of the proliferative life span of normal cells in tissue culture and occurs after cells have undergone a certain number of population doublings (PDLs). It is accompanied by alterations in the pattern of gene expression. A specific human embryonic lung diploid fibroblast cell line, 2BS, has been studied as a model of(More)