Methyl-p-hydroxyphenyllactate-esterase activity and type-II estrogen-binding sites in ovarian cancer: correlation with biological and clinico-pathological parameters

Antiproliferative effects of daucane esters fromFerula communis andF. arrigonii on human colon cancer cell lines

Certain jaesekanadiol p-hydroxy- and p-methoxybenzoates - typical of Ferula communis and Ferula arrigonii sardinian plants - show antiproliferative activity on human colon cancer less. The inhibitory doses 50%, calculated after 72 h of treatment, revealed that the antiproliferative capacity of the compounds was in the following descending order: ferutinin > 2alpha-OH-ferutidin > ferutidin > siol anisate > lapiferin > jaeskeanadiol. Evidence is presented that interaction with type II estrogen-binding sites (EBS) underlies this activity.

Growth-inhibitory effect of tamoxifen and quercetin and presence of type II estrogen binding sites in human laryngeal cancer cell lines and primary laryngeal tumors

Quercetin and tamoxifen, in a range of concentrations between 0.01 and 5 microM, exert a dose-dependent inhibition on the anchorage-dependent and anchorage-independent cell growth of Hep2 and CO-K3 laryngeal cancer cell lines. Cell cycle analysis revealed that the growth-inhibitory effect was associated with a block of the cells at the G2/M checkpoint of the cell cycle followed by DNA fragmentation. This suggests that the failure of cells to proceed through the G2/M checkpoint can be a trigger for apoptosis. The induction of apoptosis by quercetin and tamoxifen was confirmed immunocytochemically by the in situ nick end labeling (TUNEL) reaction. These compounds also exerted a dose-dependent growth-inhibitory effect on primary tumor cells, as assessed by colony-forming assay and bromodeoxyuridine labeling. Laryngeal cancer cell lines and primary tumor cells expressed Type II estrogen binding sites (Type II EBS) with binding characteristics similar to those of Type II EBS in other tumor cells. Since the affinities of quercetin and tamoxifen for Type II EBS were correlated with their growth-inhibitory potential while ipriflavone neither interacted with these sites nor inhibited cell growth, the possibility exists that the action of these compounds is mediated, at least in part, by the interaction with Type II EBS. In conclusion, our data indicate that quercetin and tamoxifen could be potentially useful in laryngeal cancer treatment.

Prognostic significance of methyl-p-hydroxy-phenyllactate-esterase activity in laryngeal squamous cell carcinoma

We assayed methyl-p-hydroxyphenyllactate esterase (MeHPLAase) activity in 63 cases of primary laryngeal squamous cell carcinoma. MeHPLAase activity did not show any correlation with oestrogen, progesterone and epidermal growth factor (EGF) receptor levels. No significant relationship was found between MeHPLAase activity and age, sex, tumour site, T classification, stage of disease and EGFR status, whereas a significant inverse relationship was found between enzymatic activity and neck lymph node positivity at presentation. The median value of MeHPLAase activity tended to be higher in tumours with low histopathological grade than in those with high histopathological grade. During the follow-up period (median 50 months, range 2-90 months) locoregional recurrences were observed in 31 out of 63 (49%) cases. At the end of the study, 27 out of 63 (43%) patients had died of cancer. Cox univariate analysis using MeHPLAase activity as a continuous covariate showed that the levels of enzymatic activity were inversely associated with the risk of death and relapse. Assuming the mean value of enzymatic activity as the cut-off value, we found a statistically significant relationship between high MeHPLAase activity and longer relapse-free and overall survival. MeHPLAase activity status retained its prognostic significance also in the lymph node-negative subgroup of patients. On multivariate analysis, both EGFR and MeHPLAase activity proved to be independent factors for predicting a short relapse and the overall survival.

Partial purification and characterization of methyl-p-hydroxyphenyllactate esterase in rat uterine cytosol

Previous studies from this laboratory have shown that methyl-p-hydroxyphenyllactate (MeHPLA) is a bioflavonoid and/or tyrosine metabolite that inhibits both normal and malignant cell proliferation, presumably, by association with nuclear type II [3H]estradiol binding sites. Conversely, the corresponding free acid, p-hydroxyphenyllactate (HPLA) possesses little, if any, cell regulatory activity. Therefore, factors that control the relative concentrations of MeHPLA and HPLA in normal or malignant mammalian tissues may also influence the rate of cellular proliferation. The experiments in this manuscript describe the characterization and purification of MeHPLA esterase from the rat uterus. These studies demonstrate that MeHPLA esterase activity is relatively homogeneous, eluting as a single peak during DEAE ion exchange chromatography and phenyl agarose hydrophobic interaction chromatography. Affi-gel Blue (Cibacron Blue F3GA) affinity chromatography resulted in a significant purification (approx. 300-fold) of the MeHPLA esterase activity, and a combination of these chromatographic steps resulted in a significant purification (> 4300-fold) of this protein. Further analysis of these esterase preparations on nondenaturing agarose gels allowed us to visualize bands of esterase activity. These studies localized one major low-mobility band of esterase activity in rat uterine cytosol preparations, which was increased by estradiol treatment. Furthermore, estrogen induction of MeHPLA esterase in the rat uterus was completely blocked (p < .01) by luteolin, although this bioflavonoid did not affect esterase activity in cytosol preparations from nonestrogenized rats. These results confirm our earlier studies demonstrating that MeHPLA hydrolysis is under estrogen regulation and that bioflavonoids antagonize estrogen action through pathways involving type II site induction and/or the regulation of MeHPLA hydrolysis in normal and malignant cells.