L-733,060

Abstract: It has been demonstrated that substance P (SP) induces cell proliferation and neurokinin-1 (NK-1) receptor antagonists inhibit growth in several human cancer cell lines, but it is currently unknown whether such actions are exerted on human laryngeal carcinoma cell line HEp-2. In addition, the presence of NK-1 receptor has not been demonstrated in this cell line. We carried out an in vitro study of the growth inhibitory capacity of the NK-1 receptor antagonists L-733,060 and L-732,138 against human laryngeal carcinoma cell line HEp-2. Coulter counter was used to determine viable cell numbers followed by application of the tetrazolium compound MTS. Furthermore, an immunoblot analysis was used to determine the NK-1 receptor, and the 4′,6-diamidino-2-phenylindole (DAPI) method was applied to demonstrate apoptosis of the laryngeal carcinoma cells. We observed the presence of several NK-1 receptors isoforms (34, 46, 58 and 75 kDa). Nanomolar concentrations of SP increased the growth rate of the cell line and micromolar concentrations of L-733,060 and L-732,138 inhibited the growth of the HEp-2 cells in a dose-dependent manner, with and without previous administration of SP. The 50% inhibition concentration values were 21.34 μM and 37.97 (48 h) respectively for HEp-2. NK-1 receptor presence on HEp-2 cells was confirmed by western blotting. DAPI staining revealed the presence of apoptosis following NK-1 receptor antagonists treatment. We demonstrated that NK-1 receptors were present in this laryngeal cancer cell line; these findings demonstrate that SP acts as a mitogen on the human laryngeal carcinoma cell line HEp-2 through the NK-1 receptor, and also indicate that both NK-1 receptors antagonists induced apoptosis of the tumour cells. This new action, reported here for the first time, suggests that the NK-1 receptor is a new and promising target in the treatment of human laryngeal carcinoma.

Abstract: Purpose 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. Methods 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. Results 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. Conclusions 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.

Abstract: Melanoma represents 1% of all cancers and accounts for approximately 65% of skin cancer deaths At present, effective treatment does not exist Substance P (SP) is a neuropeptide expressed in invasive malignant melanomas We studied the in vitro growth inhibitory capacity of the potent and long-acting neurokinin-1 (NK1) receptor antagonist L-733 060 at concentration ranges of 25-20 microM, 10-30 microM and 20-50 microM in the melanoma cell lines COLO 858, MEL H0 and COLO 679, respectively A Coulter counter was used to determine the number of viable cells, and the tetrazolium compound 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)2-(4-sulphophenyl)-2H-tetrazolium, inner salt (MTS) colorimetric method was used to evaluate cell proliferation L-733 060 inhibited the growth of all three cell lines in a dose-dependent manner The 50% inhibition concentration (IC(50)) was 87 microM at 48 h and 71 microM at 96 h for COLO 858, 275 microM at 24 h and 189 microM at 48 h for MEL H0, and 338 microM at 30 h and 315 microM at 72 h for COLO 679 These findings indicate that the NK1 receptor antagonist L-733 060 acts as an antitumoral agent This action, shown here for the first time, suggests that the NK1 receptor antagonist L-733 060 could be a promising therapeutic drug in the treatment of the human melanoma