Biomedical subjects

Yanming Zhao

Publications and source records attributed to Yanming Zhao.

4 recordsLinked to original sources

PubMed2005

Binding and phosphorylation of par-4 by akt is essential for cancer cell survival.

Activation of the PI3K-Akt pathway by loss of tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) function, increased growth factor signaling, or oncogene expression renders cancer cells resistant to apoptotic signals and promotes tumor growth. Although Akt acts as a global survival signal, the molecular circuits of this pathway have not been completely established. We report that Akt physically binds to the pro-apoptotic protein Par-4 via the Par-4 leucine zipper domain and phosphorylates Par-4 to inhibit apoptosis. Suppression of Akt activation by the PI3K-inhibitor PTEN or LY294002, Akt expression by RNA-interference, or Akt function by dominant-negative Akt caused apoptosis in cancer cells. Apoptosis induced by inhibiting Akt was blocked by inhibition of Par-4 expression, but not by inhibition of other apoptosis agonists that are Akt substrates, suggesting that inhibition of the PI3K-Akt pathway leads to Par-4-dependent apoptosis. Thus, Par-4 is essential for PTEN-inducible apoptosis, and inactivation of Par-4 by Akt promotes cancer cell survival.

Apoptosis↗

PubMed2003

Identification of a unique core domain of par-4 sufficient for selective apoptosis induction in cancer cells.

Recent studies indicated that the leucine zipper domain protein Par-4 induces apoptosis in certain cancer cells by activation of the Fas prodeath pathway and coparallel inhibition of NF-kappaB transcriptional activity. However, the intracellular localization or functional domains of Par-4 involved in apoptosis remained unknown. In the present study, structure-function analysis indicated that inhibition of NF-kappaB activity and apoptosis is dependent on Par-4 translocation to the nucleus via a bipartite nuclear localization sequence, NLS2. Cancer cells that were resistant to Par-4-induced apoptosis retained Par-4 in the cytoplasm. Interestingly, a 59-amino-acid core that included NLS2 but not the C-terminal leucine zipper domain was necessary and sufficient to induce Fas pathway activation, inhibition of NF-kappaB activity, and apoptosis. Most important, this core domain had an expanded target range for induction of apoptosis, extending to previously resistant cancer cells but not to normal cells. These findings have identified a unique death-inducing domain selective for apoptosis induction in cancer cells (SAC domain) which holds promise for identifying key differences between cancer and normal cells and for molecular therapy of cancer.

Active Transport, Cell Nucleus↗

PubMed2003

The relationship between serum interleukins and T-lymphocyte subsets in patients with severe acute respiratory syndrome.

OBJECTIVES: To observe the changes of serum interleukins (IL), T-lymphocyte subsets, and white blood cell (WBC) count in patients with severe acute respiratory syndrome (SARS), and to investigate the relationship between injured immune function, immune response and disturbed immune adjustment in SARS patients. METHODS: The levels of serum IL-2, IL-10, IL-12 and T-lymphocyte subset counts were measured in 35 clinically diagnosed SARS patients by using enzyme linked immunosorbant assay (ELISA). The relationship between the measured results and WBC count was further analyzed. RESULTS: The level of serum IL was increased to a great extent in the 35 SARS patients, and the levels of serum IL-2, IL-10 and IL-12 were 242.53 (92.69) pg/ml, 77.43 (63.37) pg/ml and 65.94 (43.21) pg/ml, respectively. The level of serum IL-2 increased markedly (P < 0.01). The peripheral blood CD(3)(+), CD(4)(+) and CD(8)(+) counts were lower than normal in 23 patients (67.7%), 26 patients (74.3%) and 15 patients (42.9%), respectively. The peripheral blood WBC counts were lower than 4.0 x 10(9)/L in 10 patients, and their CD(3)(+), CD(4)(+) and CD(8)(+) counts were 583.90 (315.58) x 10(6)/L, 272.00 (94.13) x 10(6)/L and 209.00 (72.21) x 10(6)/L, respectively. The peripheral blood WBC counts were (4.0 - 10.0) x 10(9)/L in 20 patients, and their CD(3)(+), CD(4)(+) and CD(8)(+) counts were 700.00 (502.96) x 10(6)/L, 347.00 (247.58) x 10(6)/L and 322.05 (228.47) x 10(6)/L, respectively. The peripheral blood WBC counts were higher than 10.0 x 10(9)/L in 5 patients, and their CD(3)(+), CD(4)(+) and CD(8)(+) counts were 1466.00 (630.86) x 10(6)/L, 783.00 (311.14) x 10(6)/L and 640.00 (294.40) x 10(6)/L, respectively. The decreased CD(3)(+), CD(4)(+) and CD(8)(+) counts were consistent with the decreased WBC counts. The level of IL in SARS patients was significantly higher than that in patients with chronic hepatitis B (P < 0.01). CONCLUSIONS: The level of serum IL is closely related to cell immunity in SARS patients. The level of serum IL is increased evidently while CD(3)(+), CD(4)(+) and CD(8)(+) counts decrease. Both serum IL and CD are associated with injury of immune function, and thus they could be regarded as a monitoring index for judging the condition of SARS patients and prescribing immune therapy.

Adult↗

PubMedDate not supplied

Evanescent-imaging-ellipsometry-based microarray reader.

We describe the development of a label-less ellipsometric imaging microarray reader. The ability of the ellipsometric microarray reader to measure binding of sample to microarray surface is verified using oligonucleotide complementary DNA (cDNA) microarrays. Polarized light illuminates the microarray surface through a glass substrate at an angle beyond the critical angle and changes in the polarization of totally internally reflected light resulting from binding events on the microarray surface are measured. This polarization change is used to measure the thickness of biomolecules bound to the microarray. A prototype ellipsometric imaging microarray reader is constructed and calibrated, and the performance is evaluated with cDNA microarrays. The microarray reader measures changes in refractive index changes as small as 0.0024 and thickness changes as small as 0.28 nm. The optimization of angle of incidence and substrate refractive index necessary to achieve high sensitivity is also described. This ellipsometric technique offers an attractive alternative to fluorescence-microarray readers in some genomic, proteomic, diagnostic, and sensing applications.

Algorithms↗