Interrelationship between protein phosphatase-2A and cytoskeletal architecture during the endothelial cell response to soluble products produced by human head and neck cancer

Expression of sphingosine kinase gene in the interactions between human gastric carcinoma cell and vascular endothelial cell

AIM: To study the interactions between human gastric carcinoma cell (HGCC) and human vascular endothelial cell (HVEC), and if the expression of sphingosine kinase (SPK) gene was involved in these interactions.

METHODS: The specific inhibitor to SPK, dimethyl sphingosine (DMS), was added acting on HGCC and HVEC, then the cell proliferation was measured by MTT. The conditioned mediums (CMs) of HGCC and HVEC were prepared. The CM of one kind of cell was added to the other kind of cell, and the cell proliferation was measured by MTT. After the action of CM, the cellular expression of SPK gene in mRNA level was detected with in situ hybridization (ISH).

RESULTS: DMS could almost completely inhibit the proliferation of HGCC and HVEC. The growth inhibitory rates could amount to 97.21%, 83.42%, respectively (P < 0.01). The CM of HGCC could stimulate the growth of HVEC (2.70 ± 0.01, P < 0.01) while the CM of HVEC could inhibit the growth of HGCC (52.97% ± 0.01%, P < 0.01). There was no significant change in the mRNA level of SPK gene in one kind of cell after the action of the CM of the other kind of cell.

CONCLUSION: SPK plays a key role in regulating the proliferation of HGCC and HVEC. There exist complicated interactions between HGCC and HVEC. HGCC can significantly stimulate the growth of HVEC while HVEC can significantly inhibit the growth of HGCC. The expression of SPK gene is not involved in the interactions.

The role of KDR in the interactions between human gastric carcinoma cell and vascular endothelial cell

AIM: To study the interactions between human gastric carcinoma cell (HGCC) and human vascular endothelial cell (HVEC), and the role of KDR in these interactions.

METHODS: Antisense oligodexynucleotide (ASODN) specific to KDR gene was devised and added to the culture medium of HGCC and HVEC. After the action of ASODN, the proliferation of two cells was measured by MTT method. The role of KDR in regulating the proliferation of two kinds of cells was known through observing the effect of ASODN on them. The conditioned mediums (CMs) of HGCC and HVEC were prepared. The CM of one kind of cell was added acting on the other kind of cell, then the cell proliferation was measured by MTT. After the action of ASODN or CM, the cellular expression of KDR gene was detected with in situ hybridization (ISH) for mRNA level and with immunohistochemical staining for protein level. ABC-ELISA was used to detect hVEGF in the CMs of two cells.

RESULTS: KDR ASODN could specifically inhibit the proliferation of HGCC and HVEC significantly. The growth inhibitory rate amounted to 55.35% and 54.83%, respectively (P < 0.01). HGCC and HVEC could secret a certain level of hVEGF (92.06 ± 1.69 ng/L, 77.70 ± 8.04 ng/L). The CM of HGCC could significantly stimulate the growth (2.70 ± 0.01 times) and KDR gene expression of HVEC (P < 0.01) while the CM of HVEC could significantly inhibit the growth (52.97% ± 0.01%) and KDR gene expression of HGCC (P < 0.01).

CONCLUSION: KDR plays a key role in regulating the proliferation of HGCC and HVEC. There exist complicated interactions between HGCC and HVEC. HGCC can significantly stimulate the growth of HVEC while HVEC can significantly inhibit the growth of HGCC. KDR is involved in the interactions between them.

Identification of genes associated with head and neck carcinogenesis by cDNA microarray comparison between matched primary normal epithelial and squamous carcinoma cells

In order to identify genes involved in head and neck carcinogenesis, we compared the gene expression profile in matched primary normal epithelial cells and primary head and neck cancer cells from the same patients. A cDNA microarray analysis consisting of 12 530 human genes revealed significant changes in the expression of 213 genes, with 91 genes being up-regulated and 122 being down-regulated. This comprehensive list of genes includes those associated with signal transduction (growth factors), cell structure, cell cycle, transcription, apoptosis, and cell-cell adhesion. Further analysis of nine genes involved in cell-cell interaction, using Western blot and/or reverse transcription (RT)-PCR of four paired cell lines supported the reliability of our microarray analysis. More specifically, our study provides the first evidence that claudin-7 and connexin 31.1 are down-regulated in head and neck squamous cell carcinomas (HNSCC) compared to normal cells. These findings provide a large body of information regarding gene expression profiles associated with head and neck carcinogenesis, and also represent a source of potential targets for HNSCC prevention and/or therapeutics.