Neurokinin-1 receptors located in human retinoblastoma cell lines: antitumor action of its antagonist, L-732,138.

Abstract

PURPOSE:

The authors have recently demonstrated that substance P and L-733,060 induce cell proliferation and cell inhibition, respectively, in human retinoblastoma cell lines. However, the presence of neurokinin-1 receptors has not been demonstrated in such cell lines, nor is it known whether other neurokinin-1 receptor antagonists exert antitumoral action against retinoblastoma cell lines. The purpose of this study was to demonstrate the presence of neurokinin-1 receptors in the human retinoblastoma cell lines WERI-Rb-1 and Y-79 and to study the growth inhibitory capacity of the neurokinin-1 receptor antagonist L-732,138 against those cell lines. The authors also sought to demonstrate that the administration of L-732,138 or L-733,060 induces apoptosis in retinoblastoma cells and that neurokinin-1 receptors and substance P are present in primary retinoblastoma.

METHODS:

Immunoblot analysis was used to determine neurokinin-1 receptors, and a Coulter counter was used to determine viable cell numbers; this was followed by application of the tetrazolium compound WST-8, a colorimetric method, to evaluate cell viability. DAPI stain was applied to assess chromatin condensation, characteristic of apoptosis, and immunoperoxidase was used to demonstrate neurokinin-1 receptors and substance P in eyes with primary retinoblastoma.

RESULTS:

Neurokinin-1 receptors were present in both retinoblastoma cell lines studied. Three identical bands (isoforms of approximately 33, 58, and 75 kDa) were observed in both cell lines. Moreover, L-732,138 inhibited the growth of both cell lines studied, with and without previous administration of substance P. This inhibition occurred in a dose-dependent manner, with the IC50 values of 60.47 microM for WERI-Rb1 and 56.78 microM for Y-79. Moreover, apoptosis was observed in both cell lines after the administration of L-732,138 or L-733,060. In fixed eyes with primary retinoblastoma, a high density of neurokinin-1 receptors was observed in tumor cells, whereas a very low number of such cells contained substance P.

CONCLUSIONS:

This study showed that the same isoforms of the neurokinin-1 receptor are present in human retinoblastoma cell lines WERI-Rb-1 and Y-79. Both L-732,138 and L-733,060 can induce apoptosis in these cell lines and therefore can act as antitumoral agents. Primary retinoblastoma specimens display neurokinin-1 receptor immunolabeling. These results suggest that the neurokinin-1 receptor may be a promising new target for the treatment of retinoblastoma.

• Authors: Miguel Muñoz, Marisa Rosso, Rafael Coveñas, Ignacio Montero, Miguel Angel González-Moles, María José Robles
• Journal: Investigative ophthalmology & visual science (Invest Ophthalmol Vis Sci) Vol. 48 Issue 6 Pg. 2775-81 (Jun 2007) ISSN: 0146-0404 [Print] United States
• PMID: 17525212 (Publication Type: Journal Article)

Chemical References

• Neurokinin-1 Receptor Antagonists
• Piperidines
• Receptors, Neurokinin-1
• 3,5-bis(trifluoromethyl)benzyl N-acetyltryptophan
• 3-((3,5-bis(trifluoromethyl)phenyl)methyloxy)-2-phenylpiperidine
• Substance P
• Tryptophan

Topics

• Apoptosis (drug effects)
• Blotting, Western
• Cell Count
• Cell Proliferation
• Child, Preschool
• Dose-Response Relationship, Drug
• Humans
• Immunoenzyme Techniques
• Neurokinin-1 Receptor Antagonists
• Piperidines (pharmacology)
• Receptors, Neurokinin-1 (metabolism)
• Retinal Neoplasms (metabolism, pathology)
• Retinoblastoma (metabolism, pathology)
• Stereoisomerism
• Substance P (metabolism)
• Tryptophan (analogs & derivatives, pharmacology)
• Tumor Cells, Cultured