RESUMO
Hypothyroidism is a protective factor against breast cancer but long-term exposure or overdoses of thyroid replacement therapy with thyroxine (T4) may increase breast cancer risk. OBJECTIVE: to study, in vivo and in vitro, the effects of T4 on the proliferation and apoptosis of mammary tumors of hypo- and euthyroid rats, and the possible mechanisms involved in these effects. MATERIAL AND METHODS: Female Sprague-Dawley rats were treated with a single dose of dimethylbenzathracene (15 mg/rat) at 55 days of age and were divided into three groups: hypothyroidism (HypoT; 0.01% 6-N-propyl-2-thiouracil -PTU- in drinking water, n = 20), hypothyroidism treated with T4 (HypoT + T4; 0.01% PTU in drinking water and 0.25 mg/kg/day T4 via sc; n = 20) and EUT (untreated control, n = 20). At sacrifice, tumor explants from HypoT and EUT rats were obtained and treated either with 10-10 M T4 in DMEM/F12 without phenol red with 1% Charcoalized Fetal Bovine Serum or DMEM/F12 only for 15 min to evaluate intracellular signaling pathways associated with T4, and 24 h to evaluate changes in the expression of hormone receptors and proteins related to apoptosis and proliferation by immunohistochemistry and Western Blot. RESULTS: In vivo, hypothyroidism retards mammary carcinogenesis but its treatment with T4 reverted the protective effects. In vitro, the proliferative and anti-apoptosis mechanisms of T4 were different regarding the thyroid status. In EUT tumors, the main signaling pathway involved was the cross-talk with other receptors, such as ERα, PgR, and HER2. In HypoT tumors, the non-genomic signaling pathway of T4 was the chief mechanism involved since αvß3 integrin, HER2, ß-catenin and, downstream, PI3K/AKT and ERK signaling pathways were activated. CONCLUSION: T4 can regulate mammary carcinogenesis by mainly activating its non-genomic signaling pathway and by interacting with other hormone or growth factor pathways endorsing that overdoses of thyroid replacement therapy with T4 can increase the risk of breast cancer.
Assuntos
Antracenos/efeitos adversos , Hipotireoidismo/tratamento farmacológico , Neoplasias Mamárias Experimentais/metabolismo , Piperidinas/efeitos adversos , Propiltiouracila/efeitos adversos , Transdução de Sinais/efeitos dos fármacos , Tiroxina/administração & dosagem , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Hipotireoidismo/induzido quimicamente , Neoplasias Mamárias Experimentais/induzido quimicamente , Ratos , Ratos Sprague-Dawley , Tiroxina/farmacologiaRESUMO
BACKGROUND/AIMS: Adipose microenvironment is involved in signaling pathways that influence prostate cancer (PCa) progression. However, the role of human periprostatic adipose tissue (PPAT) from patients with benign prostatic hyperplasia (BPH) has not been studied and compared to that of PPAT from PCa patients. The aim of this paper was to investigate the influence of factors derived from both PPATs on the behavior of androgen-dependent and castration resistant PCa cells. METHODS: PPAT conditioned media (CM) were obtained from tissue samples from patients with clinically primary PCa (TPPAT) or BPH (BPPAT). Cell adhesion, proliferation, migration and metalloproteinase expression were evaluated following exposure of LNCaP (androgen dependent) and PC3 (androgen independent) prostate cancer cell lines to BPPAT or TPPAT CM. RESULTS: Proliferation or motility of LNCaP or PC3 cells were not significantly affected by TPPAT or BPPAT CM. The number of LNCaP but not PC3 cells attached to components of TPPAT CM significantly decreased compared to cells attached to BPPAT CM. PPAT produced and released pro-MMP-9. Zymograms demonstrated that TPPAT CM induced a significant increase in pro-MMP-9 activity compared to BPPAT CM in LNCaP cells but not in PC3 cells. CONCLUSIONS: We conclude that TPPAT released factors, such as pro-MMP-9, could induce the invasive capacity of LNCaP cells and speculate that PPAT derived factors could, in the early stages of prostate cancer, modulate disease progression.
Assuntos
Gordura Intra-Abdominal/metabolismo , Neoplasias Hormônio-Dependentes/patologia , Próstata/patologia , Hiperplasia Prostática/patologia , Neoplasias da Próstata/patologia , Idoso , Adesão Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Transformação Celular Neoplásica/metabolismo , Meios de Cultivo Condicionados , Humanos , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Pessoa de Meia-Idade , Microambiente TumoralRESUMO
Stromal tissue regulates the development and differentiation of breast epithelial cells, with adipocytes being the main stromal cell type. The aim of the present study was to evaluate the effect of adipocyte differentiation on proliferation and migration, as well as to assess the activity of heparanase and metalloproteinase-9 (MMP-9), in normal (NMuMG) and tumoral (LM3) murine breast epithelial cells. NMuMG and LM3 cells were grown on irradiated 3T3-L1 cells (stromal support, SS) at various degrees of differentiation [preadipocytes (preA), poorly differentiated adipocytes (pDA) and mature adipocytes (MA)] and/or were incubated in the presence of conditioned medium (CM) derived from each of these three types of differentiated cells. Cells grown on a plastic support or in fresh medium served as the controls. Cell proliferation was measured with a commercial colorimetric kit, and the motility of the epithelial cells was evaluated by means of a wound-healing assay. Heparanase activity was assessed by quantifying heparin degradation, and the expression of MMP-9 was determined using Western blotting. The results indicate that cell proliferation was increased after 24 and 48 h in the NMuMG and LM3 cells grown on preA, pDA and MA SS. In the NMuMG cells cultured on SS in the presence of all three types of CM, proliferation was enhanced. LM3 cell migration was increased in the presence of all three types of CM and in cells grown on preA SS. Heparanase activity was increased in the NMuMG cells incubated with all three types of CM, and in the LM3 cells incubated with the CM from pDA and MA. Both the NMuMG and LM3 cell lines presented basal expression of MMP-9; however, a significant increase in MMP-9 expression was observed in the LM3 cells incubated with each of the three types of CM. In conclusion, adipocyte differentiation influences normal and tumoral breast epithelial cell proliferation and migration. Heparanase and MMP-9 appear to be involved in this regulation. The experimental model presented in this study is in keeping with the characteristics of the physiological environment of breast epithelial cells, in terms of both the soluble and insoluble factors present and the stromal structure per se.
RESUMO
Shiga toxin-producing Escherichia coli produces watery diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome (HUS). In Argentina, HUS is the most common cause of acute renal failure in children. The purpose of the present study was to examine the cytotoxicity of Stx type 2 (Stx2 holotoxin) and its B subunit (Stx2 B subunit) on human renal tubular epithelial cells (HRTEC), in the presence and absence of inflammatory factors. Cell morphology, cell viability, protein synthesis and apoptosis were measured. HRTEC are sensitive to both Stx2 holotoxin and Stx2 B subunit in a dose- and time-dependent manner. IL-1, LPS and butyrate but not TNF, IL-6 and IL-8, increased the Stx mediated cytotoxicity. The effects of Stx2 B subunit appear at doses higher than those used for Stx2 holotoxin. Although the physiological importance of these effects is not clear, it is important to be aware of any potentially toxic activity in the B subunit, given that it has been proposed for use in a vaccine.
Assuntos
Células Epiteliais/efeitos dos fármacos , Túbulos Renais/citologia , Túbulos Renais/efeitos dos fármacos , Subunidades Proteicas/toxicidade , Toxina Shiga II/toxicidade , Adulto , Apoptose , Butiratos/farmacologia , Células Cultivadas , Escherichia coli/patogenicidade , Humanos , Interleucina-1/farmacologia , Lipopolissacarídeos/farmacologiaRESUMO
Shiga toxin (Stx)-producing E. coli causing watery diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome (HUS). In Argentina, HUS is the most common cause of acute renal failure in children. The purpose of the present study was to examine the cytotoxicity of Stx type 2 (Stx2) and its B subunit (Stx2B) on human renal tubular epithelial cells (HRTEC), in the presence and absence of inflammatory factors. Cytotoxic effects were assessed in terms of functionality of the epithelium, histological damage, cell viability, protein synthesis and cellular apoptosis. Results show that Stx2 regulates the passage of water through the HRTEC within an incubation period of 1h. Within longer periods, up to 72 hours, the study of morphology, viability, protein synthesis and apoptosis shows that HRTEC were sensitive to the cytotoxic action of Stx2 and Stx2B in a dose- and time-dependent manner. These effects were potentiated by lipopolysaccharides (LPS), IL-1beta, and butirate.