Biomedical subjects

Cai-Hong Zhou

Publications and source records attributed to Cai-Hong Zhou.

3 recordsLinked to original sources

PubMed2007

Development of a homogeneous calcium mobilization assay for high throughput screening of mas-related gene receptor agonists.

AIM: To develop homogeneous calcium mobilization assay for high-throughput screening (HTS) of mas-related gene (Mrg) receptor agonists. METHODS: CHO-K1 cells stably expressing the full-length MrgD receptor and a calcium-sensitive dye were used to develop an HTS assay based on intracellular calcium influx. This method was applied to large-scale screening of a library containing 8000 synthetic compounds and natural product extracts. cAMP measurements were carried out to verify the bioactivities of the hits found by the calcium mobilization assay. Similar approaches were also employed in the identification of the MrgA1 receptor agonists following HTS of 16,000 samples. RESULTS: EC(50) values of the positive control compounds (beta-alanine for MrgD receptor and dynorphin A for MrgA1 receptor) determined by the calcium mobilization assay were consistent with those reported in the literature, and the Z' factors were 0.65 and 0.50 for MrgD and MrgA1 receptor assay, respectively. About 31 compounds for the MrgD receptor and 48 compounds for the MrgA1 receptor showing > or =20% of the maximal agonist activities found in the controls were initially identified as hits. Secondary screening confirmed that 2 compounds for each receptor possessed specific agonist activities. Intracellular cAMP level measurements indicated that the 2 confirmed hits displayed the functionality of the MrgD receptor agonists. CONCLUSION: A series of validation studies demonstrated that the homogeneous calcium mobilization assay developed was highly efficient, amenable to automation and a robust tool to screen potential MrgD and MrgA1 receptor agonists. Its application may be expanded to other G-protein coupled receptors that mobilize calcium influx upon activation.

Animals↗

PubMed2006

Bioactive compounds from Peperomia pellucida.

Five new compounds (1-5), including two secolignans, two tetrahydrofuran lignans, and one highly methoxylated dihydronaphthalenone, were isolated from the whole plant of Peperomia pellucida. These compounds were accompanied by the known peperomins A, B, C, and E, 7,8-trans-8,8'-trans-7',8'-cis-7,7'-bis(5-methoxy-3,4-methylenedioxyphenyl)-8-acetoxymethyl-8'-hydroxymethyltetrahydrofuran, 7,8-trans-8,8'-trans-7',8'-cis-7-(5-methoxy-3,4-methylenedioxyphenyl)-7'-(4-hydroxy-3,5-dimethoxyphenyl)-8,8'-diacetoxymethyltetrahydrofuran, sesamin, and isoswertisin. New structures were elucidated mainly by NMR and MS techniques, and anticancer activities evaluated in HL-60, MCF-7, and HeLa cell lines. Compound 1 and peperomin E show growth inhibitory effects on the three cancer cell lines with IC(50) values ranging between 1.4 and 9.1 and between 1.8 and 11.1 microM, respectively. Compound 2 has a weak suppressive activity on HL-60 cells (IC(50) = 10.8 microM), while 7,8-trans-8,8'-trans-7',8'-cis-7,7'-bis(5-methoxy-3,4-methylenedioxyphenyl)-8-acetoxymethyl-8'-hydroxymethyltetrahydrofuran exhibits estrogen-like properties (EC(50) = 3.1 microM) in CV-1 cells transfected with human estrogen receptor (ERalpha).

Antineoplastic Agents, Phytogenic↗

PubMed2002

A new model for random screening inhibitors of vascular endothelial growth factor receptor 1 kinase.

AIM: To establish a 96-well plate based kinase assay using a recombinant vascular endothelial growth factor (VEGF) receptor 1 kinase domain protein. METHODS: A human VEGF receptor 1 kinase domain protein was expressed in E coli, and its activity was monitored by its ability of phosphorylating the polyE4Y substrate coated on the walls of 96-well plates with antibody recognition and a colorimetric readout. A random screening of a sample organic compound library was carried out, and the hits were characterized with a transformed cell line stably expressing VEGF receptor 1 protein. RESULTS: An efficient E coli expression system for human VEGF receptor 1 kinase domain protein was constructed, and the purified recombinant protein was used to establish a practical screening assay for kinase inhibitors in vitro. Two thousand eight hundred organic compounds were screened, and two disubstituted furans (A1 and A5) with new structure showed inhibition of VEGF receptor 1 kinase. Compound A1 inhibited only phosphorylation of substrate, while compound A5 inhibited both autophosphorylation and substrate phosphorylation. Both inhibitors affected phosphorylation in the transformed cells. CONCLUSION: The recombinant receptor kinase based assay is simple and effective in identifying kinase inhibitors.

Angiogenesis Inhibitors↗