Effects of estradiol, progestogens, and of tibolone on breast proliferation and apoptosis.

AIM: To study the effects of estrogen therapy, alone or combined with progestogens, and of tibolone on the expression of proliferation and apoptosis markers in normal breast tissue. METHODS: Thirty 250-day-old Wistar rats were castrated and 3 weeks later received one of the following treatments by gavage for 5 weeks: (1) estradiol benzoate; (2) estradiol benzoate + medroxyprogesterone acetate; (3) estradiol benzoate + norethisterone acetate; (4) estradiol benzoate + dydrogesterone; (5) tibolone; (6) placebo. Following treatment, the expression of proliferating cell nuclear antigen (PCNA) and caspase-3 was analyzed by quantitative immunohistochemistry in the breast tissue, and proliferation and apoptosis were analyzed semiquantitatively by microscopic imaging. RESULTS: There was a statistically significant difference among the groups for PCNA, caspase-3 and the caspase-3 : PCNA ratio. Tibolone was associated with the lowest proliferative activity, followed by estradiol benzoate + dydrogesterone; however, estradiol benzoate + dydrogesterone showed the greatest rate of apoptosis. CONCLUSIONS: The various progestogens can have more or less proliferative and pro-apoptotic effects than estradiol alone. Among the treatment schemes analyzed, the estradiol + dydrogesterone combination resulted in a higher apoptosis rate in relation to the proliferation rate and tibolone was associated with the lowest proliferation.

Is expression of rat breast matrix components influenced by estrogen, progestins and tibolone?

AIM: To study the effects of estrogen therapy, alone or combined with progestogens, and of tibolone on the expression of heparanase (HSPE), extracellular matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9), perlecan and proliferating cell nuclear antigen (PCNA) in normal breast tissue. METHODS: Thirty 250-day-old Wistar rats were castrated and 3 weeks later received one of the following treatments by gavage for 5 weeks: (1) estradiol benzoate; (2) estradiol benzoate + medroxyprogesterone acetate; (3) estradiol benzoate + norethisterone acetate; (4) estradiol benzoate + dydrogesterone; (5) tibolone; (6) placebo. Following treatment, the expressions of mRNA for HSPE, MMP-2 and MMP-9 were analyzed by real-time PCR and the protein expressions of HSPE, MMP-2, MMP-9, perlecan and PCNA were quantified by immunohistochemistry. RESULTS: There was a statistically significant difference among the groups for the expression of HSPE mRNA due to high levels in the tibolone group. The groups differed in terms of PCNA, with lower levels found in the tibolone group followed by the estradiol benzoate + dydrogesterone group. A statistically significant positive correlation was observed for PCNA versus perlecan and MMP-9. CONCLUSIONS: There was no difference in the effects of combinations of estradiol and different progestogens on extracellular matrix components, and breast cell proliferation was associated with increases in perlecan and MMP-9.

Effect of estrogen therapy on vascular perlecan and metalloproteinases 2 and 9 in castrated rats.

AIM: To study the effects of estrogen therapy on the expression of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) and perlecan in the vascular wall. METHODS: Twenty 180-day-old Wistar rats were castrated and treated 1 week later for a period of 4 weeks with one of the following: (1) placebo; (2) 0.5 µg/day estradiol benzoate (E(2)B); (3) 5 µg/day E(2)B; (4) 50 µg/day E(2)B. A fifth group consisted of rats that had not been castrated. Following treatment, expression of MMP-2 and MMP-9 mRNA (MMP-2([RNA]) and MMP-9([RNA]), respectively) was analyzed by real-time PCR, and expression of MMP-2 (MMP-2([IH])), MMP-9 (MMP-9([IH])) and perlecan was quantified by immunohistochemistry, in carotid walls. RESULTS: There were no differences among castrated groups for MMP-2([RNA]) (p = 0.1969) and for MMP-9([RNA]) (p = 0.1828); however, a correlation was observed between E(2)B dose and MMP-9([RNA]) levels (r = 0.471, p = 0.018). Differences among groups were observed for MMP-2([IH]), MMP-9([IH]) and perlecan (p < 0.0001), wherein higher levels were observed in animals treated with estrogen therapy, correlating with E(2)B doses in the case of MMP-9 (r = 0.441, p = 0.026) and perlecan (r = 0.574, p = 0.005). CONCLUSIONS: Estrogen therapy correlates with higher levels of MMP-2, MMP-9 and perlecan in the extracellular matrix of carotid walls in castrated rats, in a dose-dependent manner. There was a dose-response effect of E(2)B on the expression of MMP-9 mRNA and, possibly, MMP-2 mRNA.

Methylene blue photodynamic therapy in malignant melanoma decreases expression of proliferating cell nuclear antigen and heparanases.

BACKGROUND: Malignant melanoma (MM) is a very aggressive tumour. Although surgical excision of MM in the early stages has a very good prognosis, it often fails to completely inhibit tumour progression. Methylene blue photodynamic therapy (MB-PDT) is a technique that induces tissue damage by reactive oxygen species (ROS). AIM: To investigate the efficacy of and potential use of MB-PDT in restraining the aggressiveness of MM by analysing levels of proliferating cell nuclear antigen (PCNA) and heparanase (HPSE, a molecular marker of cell invasion) in a mouse model. METHODS: Expression of PCNA and two HPSE isoforms were analysed using immunohistochemistry (IHC) after MB-PDT in mice. Tumour volume and weight were also measured. RESULTS: Two treatments with MB-PDT promoted a decrease of 99% decrease in tumour volume and 75% in tumour weight compared with untreated mice (P < 0.05). Using IHC, a decrease in expression of 75% for PCNA and 95% for both HPSE isoforms (P < 0.05) was found. CONCLUSION: MB-PDT is a cheap and efficient method of decreasing MM volume and thus disease progression. This reduction is mediated by downregulation of PCNA and heparanases.

EJ-ras oncogene transfection of endothelial cells upregulates the expression of syndecan-4 and downregulates heparan sulfate sulfotransferases and epimerase.

The EC rabbit endothelial cell line was transfected with the EJ-ras oncogene (EJ-ras EC). EJ-ras EC cells display over expression of the Ras oncogene, morphological changes and deregulation of the cell cycle, becoming more densely populated and serum-independent. In addition, EJ-ras-transfectant cells show higher levels of the syndecan-4 mRNA. In addition to the increase in the core protein, a parallel increase in the glycosylation of the syndecan-4 protein, a proteoglycan that bears heparan sulfate chains, also occurs. This increase is observed both for the heparan sulfate proteoglycan synthesized by the cells and for that secreted to the culture medium. This enhancement in heparan sulfate synthesis was observed through metabolic labeling of the cells, immunoprecipitation of syndecan-4 and heparitinases treatment. Furthermore, the EJ-ras-transfectant cells do not exhibit decreased synthesis of heparan sulfate during the G(1)-S phase transition, as observed for the parental cell line. Also, heparan sulfate synthesis is not stimulated by PMA as displayed by parental endothelial cells. Significant structural changes of heparan sulfate, such as decreased O-sulfation, were observed in the EJ-ras-transfected cells. Decreases in the mRNA levels of some enzymes (glucuronosyl C-5 epimerase, iduronosyl-2-O-sulfotransferase, glucosaminyl-6-O-sulfotransferase-1 and N-deacetylase/N-sulfotransferase-1), involved in the biosynthetic pathway of heparan sulfate, were also observed. The results suggest that overexpression of the EJ-ras oncogene alters the cell cycle, through signal transduction cascades, upregulates the expression of syndecan-4, and downregulates enzymes involved in the heparan sulfate biosynthesis related to chain modification, leading to the structural changes of the heparan sulfate syndecan-4 proteoglycan in endothelial cells.

Immunohistochemical expression of heparanase isoforms and syndecan-1 proteins in colorectal adenomas.

The proteoglycan syndecan-1 and the endoglucuronidases heparanase-1 and heparanase-2 are involved in molecular pathways that deregulate cell adhesion during carcinogenesis. Few studies have examined the expression of syndecan-1, heparanase-1 and mainly heparanase-2 proteins in non-neoplastic and neoplastic human colorectal adenoma tissues. The aim of this study was to analyze the correlation among the heparanase isoforms and the syndecan-1 proteins through immunohistochemical expression in the tissue of colorectal adenomas. Primary anti-human polyclonal anti-HPSE and anti-HPSE2 antibodies and primary anti-human monoclonal anti-SDC1 antibody were used in the immunohistochemical study. The expressions of heparanase-1 and heparanase-2 proteins were determined in tissue samples from 65 colorectal adenomas; the expression of syndecan-1 protein was obtained from 39 (60%) patients. The histological type of adenoma was tubular in 44 (67.7%) patients and tubular-villous in 21 (32.3%); there were no villous adenomas. The polyps were <1.0 cm in size in 54 (83.1%) patients and ≥1.0 cm in 11 (16.9%). The images were quantified by digital counter with a computer program for this purpose. The expression index represented the relationship between the intensity expression and the percentage of positively stained cells. The results showed that the average of heparanase-1, heparanase-2 and syndecan-1 expression index was 73.29 o.u./µm², 93.34 o.u./µm², and 55.29 o.u./µm², respectively. The correlation between the heparanase-1 and syndecan-1 expression index was positive (R=0.034) and significant (P=0.035). There was a negative (R= -0.384) and significant (P=0.016) correlation between the expression index of heparanase-1 and heparanase-2. A negative (R= -0.421) and significant (P=0.008) correlation between the expression index of heparanase-2 and syndecan-1 was found. We concluded that in colorectal adenomas, the heparanase-1 does not participate in syndecan-1 degradation; the heparanase-2 does not stimulate syndecan-1 degradation by the action of heparanase-1, and the heparanase-2 may be involved in the modulation of the heparanase-1 activity.

Development of new heparin-like compounds and other antithrombotic drugs and their interaction with vascular endothelial cells

The anticlotting and antithrombotic activities of heparin, heparan sulfate, low molecular weight heparins, heparin and heparin-like compounds from various sources used in clinical practice or under development are briefly reviewed. Heparin isolated from shrimp mimics the pharmacological activities of low molecular weight heparins. A heparan sulfate from Artemia franciscana and a dermatan sulfate from tuna fish show a potent heparin cofactor II activity. A heparan sulfate derived from bovine pancreas has a potent antithrombotic activity in an arterial and venous thrombosis model with a negligible activity upon the serine proteases of the coagulation cascade. It is suggested that the antithrombotic activity of heparin and other antithrombotic agents is due at least in part to their action on endothelial cells stimulating the synthesis of an antithrombotic heparan sulfate.

Binding of heparin and compound Y to endothelial cells stimulates the synthesis of an antithrombotic heparan sulfate proteoglycan

The mechanism by which heparin and antithrombotic agents, including a cyclic octaphenolsufonic acid (compound Y), stimulate the synthesis of an antithrombotic heparan sulfate by endothelial cells in culture was investigated. Compound Y increases the amount of heparan sulfate from the cell surface and secreted to the endothelial cell receptors at a concentration of 0.16µM for heparin and 2.7µM for compound Y. The kinetic binding constants (Ks) for compound Y and heparin were 1,333 nM and 42 nM, respectively. It was also shown that both compounds bind to the same receptors. The Scatchard plots indicated that 1,319 nmoles compound Y and 35 nmoles heparin bound per microgram cell protein, indicating that 40-fold more molecules of compound Y bound to the receptors when compared to heparin. No significant internalization of the compounds was observed