Efeitos dos ácidos graxos ômega-3 na modulação da carcinogênese prostática em camundongos TRAMP
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Data
2021-09-02
Autores
Silva, Alana Della Torre da
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Universidade Estadual Paulista (Unesp)
Resumo
O adenocarcinoma de próstata (CaP) é o câncer mais comum em homens no mundo e a segunda causa de mortalidade por câncer no Brasil. O consumo de ácidos graxos poli-insaturados ômega-3 (ω3), como o ácido docosahexaenóico (DHA) e eicosapentaenóico (EPA), tem sido relacionados com menor risco de CaP e melhor prognóstico, mas os dados ainda são conflitantes e essa questão é inconclusiva. O presente estudo avaliou os efeitos da dieta enriquecida em DHA/EPA (Dω3) na progressão tumoral do CaP, no lobo dorsolateral (LDL) da próstata de camundongos transgênicos para o adenocarcinoma de próstata (TRAMP), e o impacto sobre os processos de morte celular regulada, usando para isso também experimentos in vitro. Os camundongos (8 sem. idade) foram alimentados pelo período de 1 ou 3 meses com dieta contendo 10% de óleo de peixe (grupos T12 e T20, respectivamente) ou dieta padrão para roedores (grupos C12 e C20). Também foram analisados camundongos com 8 sem. idade alimentados com ração padrão (C8), fase em que se iniciam os distúrbios proliferativos. Os LDLs foram processados para análises histopatológicas, estereológicas, imuno-histoquímicas, TUNEL e ensaio de caspase 3 ativa. A Dω3 por 1 mês aumentou a frequência de áreas epiteliais saudáveis (2,4x) e reduziu as de lesões pré-malignas (2,7x) e de carcinoma in situ (2,3x), em comparação com o controle. 50% dos animais dos grupos C20 e T20 desenvolveram tumor primário e não houve variação do peso tumoral entre esses grupos. Contudo, nos demais animais, para os quais o LDL pode ser isolado, também se verificou aumento na frequência de áreas epiteliais saudáveis (2,2x) e redução nas de lesões pré-malignas (2,9x) e de carcinoma in situ (2,9x) em T20 comparado a C20. A histologia do LDL dos grupos T12 e T20 e proporção de áreas de tecido epitelial, lúmen e estroma se mantiveram semelhantes as do C8. Nos dois tempos de consumo, a Dω3 reduziu a proliferação celular e a expressão tecidual epitelial de AR e ER-α. Também manteve as características estromais, evitando o aumento de fibras colágenas, de células α-SMA+ e de linfócitos T-CD3+ que ocorre durante a progressão da doença. A Dω3 aumentou a autofagia em ambos os tempos e a taxa de apoptose no tempo mais longo de consumo (31,25%), mas não afetou a necroptose e piroptose que foram mais restritas às células imunes estromais. Experimentos com cultura de células epiteliais prostáticas benignas (PNT1A) e tumorais responsivas a andrógenos (22rv1), tratadas com DHA (100µM, 48h), aliados a análises de Western Blotting, mostraram que esse ω3 aumenta 8,6% a autofagia e inibe 27,3% a piroptose na linhagem tumoral, enquanto reduz a necroptose (50%) na benigna. Conclui-se que a intervenção dietética com ω3 no período mais curto diminui a gravidade e atrasa a progressão tumoral do CaP em camundongos TRAMP, via redução da expressão tecidual de AR e ER-α, bloqueio da atividade proliferativa, modulação da morte celular regulada e preservação do microambiente estromal. Esses achados sugerem uma ação protetora dos ω3 no CaP e seu possível uso como adjuvante terapêutico nos estágios iniciais da doença, mas reforçam a necessidades de estudos adicionais sobre seu impacto nas fases mais avançadas da doença.
Prostate adenocarcinoma (CaP) is the most common cancer in men worldwide and the second leading cause of death by cancer-related cases in Brazil. The intake of omega-3 polyunsaturated fatty acids (ω3), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been linked to lower risk of CaP development and positive prognostic, however, data regarding ω3 intake is still conflicting and inconclusive. Here, we evaluated the effects of a DHA/EPA-enriched diet (Dω3) in tumor progression in the dorsolateral lobe (LDL) of the prostate of the transgenic adenocarcinoma of the mouse prostate (TRAMP mice), and the impact on regulated cell death using both in vivo and in vitro approaches. Mice (8 wk) were fed for 1 or 3 months with a diet containing 10% fish oil (groups T12 and T20, respectively) or a standard rodent diet (groups C12 and C20). Additionally, 8 wk-old-mice fed standard diet (C8) were also analyzed once the proliferative disorders began to develop at this age. LDLs were processed for histopathological, stereological, immunohistochemical, TUNEL, and activated caspase 3 assays. Dω3 for 1 month increased the frequency of healthy epithelial areas (2.4x) and reduced the frequency of both premalignant lesions (2.7x) and carcinoma in situ (2.3x) compared to the control groups. Half of the animals at 20 weeks of age developed primary tumors regardless of their diet and there was no variation in tumor weight between these groups. However, T20 animals that did not develop primary tumors for which LDL was properly isolated displayed and an increase in the frequency of healthy epithelial areas (2.2x) and a reduction of premalignant lesions (2.9x) and carcinoma in situ (2.9x) in this lobe compared to C20. The morphology of LDL in T12 and T20 groups and the frequencies of acinar epithelium, lumen, and stromal areas remained similar to those of C8. In both periods, Dω3 reduced cell proliferation and tissue expression of AR and ER-α in the epithelium. It also maintained the stromal characteristics, preventing the increase in collagen fibers, α-SMA+ cells, and T-CD3+ lymphocytes that occurs during disease progression. Dω3 increased autophagy in both groups, but only the T20 group display an increase in apoptosis rate (31.25%), and no differences were observed in necroptosis and pyroptosis, which were more frequent restricted to stromal immune cells. Treatment of the benign prostatic epithelial (PNT1A) and androgen-responsive (22rv1) cell lines with DHA (100µM, 48h), showed that this ω3 increases autophagy by 8.6% and inhibits 27.3% pyroptosis in the tumor lineage, whereas it reduces necroptosis (50%) in the benign cell line. Thus, our data indicate that dietary intervention with ω3 in the shortest period decreases the severity of the disease and delays tumor progression in TRAMP mice, via downregulation of tissue expression of AR and ER-α, decrease of proliferative activity, modulation of regulated cell death and improvement of the stromal microenvironment. These findings suggest a protective action of ω3 on CaP and highlight its possible application as a therapeutic adjuvant in the early stages of the disease although it reinforces the need for further studies of its impact in advanced stages of the disease.
Prostate adenocarcinoma (CaP) is the most common cancer in men worldwide and the second leading cause of death by cancer-related cases in Brazil. The intake of omega-3 polyunsaturated fatty acids (ω3), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been linked to lower risk of CaP development and positive prognostic, however, data regarding ω3 intake is still conflicting and inconclusive. Here, we evaluated the effects of a DHA/EPA-enriched diet (Dω3) in tumor progression in the dorsolateral lobe (LDL) of the prostate of the transgenic adenocarcinoma of the mouse prostate (TRAMP mice), and the impact on regulated cell death using both in vivo and in vitro approaches. Mice (8 wk) were fed for 1 or 3 months with a diet containing 10% fish oil (groups T12 and T20, respectively) or a standard rodent diet (groups C12 and C20). Additionally, 8 wk-old-mice fed standard diet (C8) were also analyzed once the proliferative disorders began to develop at this age. LDLs were processed for histopathological, stereological, immunohistochemical, TUNEL, and activated caspase 3 assays. Dω3 for 1 month increased the frequency of healthy epithelial areas (2.4x) and reduced the frequency of both premalignant lesions (2.7x) and carcinoma in situ (2.3x) compared to the control groups. Half of the animals at 20 weeks of age developed primary tumors regardless of their diet and there was no variation in tumor weight between these groups. However, T20 animals that did not develop primary tumors for which LDL was properly isolated displayed and an increase in the frequency of healthy epithelial areas (2.2x) and a reduction of premalignant lesions (2.9x) and carcinoma in situ (2.9x) in this lobe compared to C20. The morphology of LDL in T12 and T20 groups and the frequencies of acinar epithelium, lumen, and stromal areas remained similar to those of C8. In both periods, Dω3 reduced cell proliferation and tissue expression of AR and ER-α in the epithelium. It also maintained the stromal characteristics, preventing the increase in collagen fibers, α-SMA+ cells, and T-CD3+ lymphocytes that occurs during disease progression. Dω3 increased autophagy in both groups, but only the T20 group display an increase in apoptosis rate (31.25%), and no differences were observed in necroptosis and pyroptosis, which were more frequent restricted to stromal immune cells. Treatment of the benign prostatic epithelial (PNT1A) and androgen-responsive (22rv1) cell lines with DHA (100µM, 48h), showed that this ω3 increases autophagy by 8.6% and inhibits 27.3% pyroptosis in the tumor lineage, whereas it reduces necroptosis (50%) in the benign cell line. Thus, our data indicate that dietary intervention with ω3 in the shortest period decreases the severity of the disease and delays tumor progression in TRAMP mice, via downregulation of tissue expression of AR and ER-α, decrease of proliferative activity, modulation of regulated cell death and improvement of the stromal microenvironment. These findings suggest a protective action of ω3 on CaP and highlight its possible application as a therapeutic adjuvant in the early stages of the disease although it reinforces the need for further studies of its impact in advanced stages of the disease.
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Palavras-chave
Ácidos graxos ômega-3, Câncer de próstata, Camundongos TRAMP, Ácido docosahexaenóico, Células prostáticas, Omega-3 fatty acids, Prostate cancer, TRAMP mice, Docosahexaenoic acid, Prostatic Cells