Impact of lower concentrations of phytoestrogens on the effects of estradiol in breast cancer cells.

OBJECTIVE: To explore the impact of lower concentrations of phytoestrogens on 17ß-estradiol (E2) in the growth of MCF-7 breast cells. METHODS: MCF-7 cells were treated with E2 (10(-8) mol/l), one of three phytoestrogens (genistein, resveratrol, and quercetin) (10(-7)  to 10(-5) mol/l), and with a combination of both E2 and one of these phytoestrogens for 48 h. These cells were then extracted for MTT and TUNEL assay. Western blot was utilized to evaluate the proteins involved in the proliferative and apoptotic pathways, as well as the differential effects on ERα and ß. RESULTS: MCF-7 cell proliferations were induced by both E2 alone and E2 plus one of the three phytoestrogens (at concentrations ≥ 10(-6) mol/l). Apoptotic cells were significantly increased in the phytoestrogen-treated MCF-7 cells and, conversely, suppressed in the cells treated with both E2 and phytoestrogens. Proliferating cell nuclear antigen, PI3K and p-Akt were increased in the cultures with E2 and substantially more in the cultures with E2 plus a phytoestrogen. The combination of E2 and phytoestrogen significantly inhibited the increase in FADD, cytochrome C, truncated Bid, caspase-9, caspase-3 and ERß that was induced by phytoestrogens in the MCF-7. ERα expression was significantly induced by E2 regardless of the presence of these phytoestrogens. CONCLUSIONS: This study demonstrates that, in the presence of E2, genistein, resveratrol, and quercetin may stimulate breast cancer cells, even at low physiological concentrations. Therefore, the conflicting results regarding the effects of phytoestrogens on breast cells may be attributed to the endogenous estrogen present in breast tissue.

Lower concentrations of phthalates induce proliferation in human breast cancer cells.

OBJECTIVE: To explore the effect and pathway of phthalates on the growth of MCF-7 breast cancer cells. METHODS: MCF-7 cells were treated with benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), and di-2-ethylhexyl phthalate (DEHP) (10(-10)-10(-4) mol/l). After incubation for 24, 48, 72, and 92 h, the cells were harvested and extracted for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The proteins involving proliferative and apoptotic pathways were evaluated by Western blot analysis. RESULTS: MTT assay revealed cell toxicity at more than 10(-5) mol/l for DEHP and at 10(-4) mol/l for both BBP and DBP in MCF-7 cells. Cell proliferation was significantly increased at 10(-8)-10(-5) mol/l of BBP and DBP, and at 10(-8)-10(-6) mol/l of DEHP treatment. Proliferating cell nuclear antigen (PCNA) was substantially increased in cultures with DEHP (10(-8)-10(-6) mol/l), BBP (10(-8)-10(-5) mol/l), and DBP (10(-7)-10(-5) mol/l). Obvious increases in PI3K, p-AKT, and PCNA were noted in cultures with 17ß-estradiol, BBP, DBP, and DEHP. Estrogen receptor α expression was also notably increased in treatment with estradiol, BBP, DBP, and DEHP. CONCLUSIONS: The present study demonstrates that, even at a very low concentration, BBP, DBP, and DEHP were not only still capable of inducing a proliferative effect through the PI3K/AKT signaling pathway but also displaying estrogenic activity. Therefore, the current reference doses for phthalates defined by governments should be further evaluated.

Phytoestrogens induce differential effects on both normal and malignant human breast cells in vitro.

OBJECTIVE: To explore the effect and pathway of phytoestrogens in vitro on the growth of both normal and malignant breast cells. METHODS: Normal breast MCF-10A cells and breast cancer MCF-7 cells were incubated with 10 (-10)-10(-4)  mol/l genistein, resveratrol, and quercetin (plasma concentrations in human: 10 nmol/l-10 µmol/l) for 48 h and were then extracted for a cell proliferation assay (MTT), and for a cell death assay (TUNEL) assay. The proteins involved in the proliferative and apoptotic pathways were evaluated by Western blot analysis. Additionally, a comparison with 17ß-estradiol as well as an evaluation of the differential effects on estrogen receptors (ER) α and ß were performed. RESULTS: MCF-7 cell proliferation was significantly inhibited at the concentrations greater than 10(-4) mol/l for all three phytoestrogens and from 10 (-5) mol/l for resveratrol and quercetin. MCF-10A cell proliferation was significantly increased at the concentrations from 10 (-8) to 10 (-5) mol/l for genistein and resveratrol and only at 10 (-5) mol/l for quercetin. Apoptotic cells were significantly increased by these phytoestrogens in the MCF-7 cells. At a concentration of 10 (-7)  mol/l of these phytoestrogens, a significant reduction of PI3K and Akt and an increase of Fas ligand, Fas-associated protein with death domain, cytochrome C, truncated Bid, caspase-9, and caspase-3 were noted in the MCF-7; PI3K and Akt were significantly increased in the MCF-10A. ERß expression was significantly elevated in MCF-10A and MCF-7 with these phytoestrogens. The effects of estradiol on normal and malignant breast cells were completely opposite to those of phytoestrogens. CONCLUSIONS: This study demonstrates that phytoestrogens have antiproliferative effects on breast cancer cells via an ER-dependent mechanism, even at low concentrations, but are also capable of maintaining the survival of normal breast cell via ER-independent or other mechanisms.

Phytoestrogens induce apoptosis through a mitochondria/caspase pathway in human breast cancer cells.

OBJECTIVE: To explore the effect and pathway of phytoestrogens on the growth of breast cancer cell line MCF-7. METHODS: MCF-7 cells (human estrogen receptor-positive and progesterone receptor-positive breast cancer cells) were cultured in serum-free medium for 24 h and then treated with genistein, resveratrol, and quercetin (10(-10)-10(-4) mol/l). After further incubation for 24, 48, 72, and 92 h, the cells were harvested and extracted for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. According to the above results, the proteins involving proliferative and apoptotic pathways were evaluated by Western blot analysis. RESULTS: Genistein, resveratrol, and quercetin significantly inhibited cellular proliferation in a dose- and time-dependent manner. Significantly elevated caspase-3 activity was noted after treatment with genistein (10(-9)-10(-7) mol/l), as well as with resveratrol and quercetin (10(-9)-10(-5) mol/l). Significant reduction of PI3K and AKT protein and significant increase of Fas ligand, Fas-associated protein with death domain, cytochrome C, truncated Bid, caspase-9, and caspase-3 were all noted after genistein, resveratrol, and quercetin treatment. 17ß-Estradiol induced completely opposite results. Estrogen receptor (ER) α expression was significantly increased with 17ß-estradiol, whereas ERß expression was significantly elevated in the cultures with genistein, resveratrol, and quercetin. CONCLUSIONS: These data demonstrate that genistein, resveratrol, and quercetin have antiproliferative effects on breast cancer cells. Their induction of apoptosis involves the activation of both the intrinsic and extrinsic apoptotic pathways, which may be related to the differential affinity to ERα and ERß. Whether phytoestrogens have similar effects on normal breast cells remains to be examined.

Impact of interleukin-8 gene polymorphisms and environmental factors on oral cancer susceptibility in Taiwan.

OBJECTIVES: Interleukin-8 (IL-8), which is an angiogenic chemokine with a high expression level in tumor tissues, plays important roles in developing many human malignancies including oral squamous cell carcinoma (OSCC). This study was designed to examine the association of IL-8 gene polymorphisms with the susceptibility and clinicopathological characteristics of OSCC. METHODS: A total of 270 patients with OSCC and 350 healthy control subjects were recruited. Four single nucleotide polymorphisms (SNPs) of IL-8 genes were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping analysis. RESULTS: Results showed that four IL-8 SNPs (-251 T/A, +781 C/T, +1633 C/T, and +2767 A/T) were not associated with oral cancer susceptibility as well as clinicopathological parameters. But among 345 smokers, IL-8 polymorphisms carriers with betel quid chewing were found to have a 17.41- to 23.14-fold risk to have oral cancer compared to IL-8 wild-type carriers without betel quid chewing. Among 262 betel quid chewers, IL-8 polymorphisms carriers with smoking have a 10.54- to 20.44-fold risk to have oral cancer compared to those who carried wild type without smoking. CONCLUSIONS: Our results suggest that the combination of IL-8 gene polymorphisms and environmental carcinogens might be highly related to the risk of oral cancer.

Role of lipocalin 2 and its complex with matrix metalloproteinase-9 in oral cancer.

OBJECTIVES: Recent evidence demonstrated that lipocalin (LCN)2 is induced in many types of human cancer, while the detection of its complex with matrix metalloproteinase (MMP)-9 is correlated with the cancer disease status. We attempted to evaluate plasma expressions of LCN2, MMP-9, and their complex (LCN2/MMP-9) during the diagnostic work-up of patients with oral squamous cell carcinoma (OSCC) and investigated their correlations with disease progression. METHODS: In total, 195 patients with OSCC and 81 healthy controls were recruited. Expression levels of LCN2, MMP-9, and LCN2/MMP-9 were determined with immunoenzymatic assays. RESULTS: Patients with OSCC exhibited significantly higher levels of LCN2, MMP-9, and LCN2/MMP-9 compared with healthy controls (LCN2: P < 0.001; MMP-9: P < 0.001; LCN2/MMP-9: P < 0.01). Plasma levels of LCN2, MMP-9, and LCN2/MMP-9 in patients with OSCC were significantly correlated with each other and were associated with more-advanced clinical stages (P < 0.05) and/or a larger tumor size (P < 0.05), but were not associated with positive lymph-node metastasis or distal metastasis. CONCLUSION: Our results suggest that plasma levels of LCN2 and the LCN2/MMP-9 complex may be useful in non-invasively monitoring OSCC progression, while supporting their potential role as biomarkers of oral cancer disease status.

Effects of different progestogens on human breast tumor cell growth.

OBJECTIVE: To examine the effect of progestogens currently used in hormone therapy on growth of human breast tumor cells. METHODS: MCF-7 cells were incubated in 10 nmol/l progestogens, including progesterone (P4), medroxyprogesterone acetate (MPA), norethisterone acetate (NETA), and cyproterone acetate (CPA), with or without 17ß-estradiol (E(2), 1 nmol/l and 10 nmol/l), as well as E(2) alone. Cell proliferation, apoptosis, and the expression of caspase-3 and proliferating cell nuclear antigen (PCNA) were evaluated. RESULTS: The ratios of apoptosis : proliferation significantly increased in cultures with progestogens alone, 1 nmol/l E(2) plus progestogens (except P4), and 10 nmol/l E(2) plus NETA. Caspase-3 significantly diminished in cultures with E(2) alone; this was completely reversed when progestogens were added. MPA alone or with 1 nmol/l E(2) and 10 nmol/l E(2) plus NETA significantly increased caspase-3. Using progestogens alone, except P4, significantly decreased PCNA expression. CONCLUSIONS: The results demonstrate that various progestogens have different effects on growth of breast tumor cells, especially with the combined usage of E(2). Progestogen-induced apoptosis may be partly inhibited with the presence of E(2), but less severe with lower E(2) concentrations. Therefore, the choice of progestogens, as well as the doses of E(2) and/or progestogen, may influence breast cancer risk.

MiR-520h-mediated FOXC2 regulation is critical for inhibition of lung cancer progression by resveratrol.

Resveratrol, a phytochemical found in various plants and Chinese herbs, is associated with multiple tumor-suppressing activities, has been tested in clinical trials. However, the molecular mechanisms involved in resveratrol-mediated tumor suppressing activities are not yet completely defined. Here, we showed that treatment with resveratrol inhibited cell mobility through induction of the mesenchymal-epithelial transition (MET) in lung cancer cells. We also found that downregulation of FOXC2 (forkhead box C2) is critical for resveratrol-mediated suppression of tumor metastasis in an in vitro and in vivo models. We also identified a signal cascade, namely, resveratrol-∣miRNA-520h-∣PP2A/C-∣Akt → NF-κB → FOXC2, in which resveratrol inhibited the expression of FOXC2 through regulation of miRNA-520h-mediated signal cascade. This study identified a new miRNA-520h-related signal cascade involved in resveratrol-mediated tumor suppression activity and provide the clinical significances of miR-520h, PP2A/C and FOXC2 in lung cancer patients. Our results indicated a functional link between resveratrol-mediated miRNA-520h regulation and tumor suppressing ability, and provide a new insight into the role of resveratrol-induced molecular and epigenetic regulations in tumor suppression.

A novel nomenclature for the hypervariable short tandem repeat APOAI1.

A novel nomenclature for the hypervariable microsatellite DNA, APOAI1 locus, is proposed. The complex nature of the repeat unit in this locus results in alleles separated by a single base. Polymerase chain reaction (PCR) products amplified from this locus were separated by single-strand conformation polymorphism (SSCP) electrophoresis. All the single-stranded DNA bands on the SSCP gel were removed from the gel and a second amplification performed. Homozygous DNA fragments amplified from single-stranded DNA were sequenced. From the 100 individuals studied, 30 alleles and 73 genotypes were found. A system of nomenclature for the APOAI1 locus is provided that is logical and in line with previous models. Using the primers described, the locus can be amplified and alleles designated on the basis of size. This system of nomenclature will assist in the exchange of data between laboratories for this locus.