piperidines and Retinoblastoma

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.. 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.. 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.. 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.

Topics: Apoptosis; Blotting, Western; Cell Count; Cell Proliferation; Child, Preschool; Dose-Response Relationship, Drug; Humans; Immunoenzyme Techniques; Neurokinin-1 Receptor Antagonists; Piperidines; Receptors, Neurokinin-1; Retinal Neoplasms; Retinoblastoma; Stereoisomerism; Substance P; Tryptophan; Tumor Cells, Cultured

Activation of the neurokinin-1 receptor is known to induce proliferation in tumor cells, but it is as yet unknown whether this applies to retinoblastoma. This was an in vitro study of the growth inhibitory capacity of the potent and long-acting neurokinin-1 receptor antagonist L-733,060, at concentrations ranging from 7.5 to 20 microM, against the human retinoblastoma line WERI-Rb-1 and from 10 to 25 microM against the human retinoblastoma line Y-79. The ability of substance P (an neurokinin-1 stimulator) to activate the cell growth of these retinoblastoma cell lines was also determined.. A cell counter was used to determine the number of viable cells, followed by application of the tetrazolium compound WST-8 [2-(2-methoxy-4-nitrophenyl)-3-(4 nitrophenyl))-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt, colorimetric method to evaluate cell viability in this cytotoxicity assay.. Nanomolar concentrations of substance P increased the growth of both cell lines and micromolar concentrations of L-733,060 inhibited the growth of the two cell lines studied, with and without previous administration of substance P. L-733,060 inhibited the growth of the WERI-Rb-1 and Y-79 cell lines in a dose-dependent manner. IC50 was 12.15 microM for 49 hours for WERI-Rb1 and 17.38 microM for 40 hours for Y-79.. The findings demonstrate that substance P is a mitogen and also indicate that the neurokinin-1 receptor antagonist L-733,060 acts on both human retinoblastoma cell lines as an antitumoral agent.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Humans; Mitogens; Neurokinin-1 Receptor Antagonists; Piperidines; Retinal Neoplasms; Retinoblastoma; Substance P; Tetrazolium Salts