Photodynamic therapy reduces cell viability, migration and triggers necroptosis in prostate tumor cells.

Prostate cancer is the most common cancer in American men, aside from skin cancer. As an alternative cancer treatment, photodynamic laser therapy (PDT) can be used to induce cell death. We evaluated the PDT effect, using methylene blue as a photosensitizer, in human prostate tumor cells (PC3). PC3 were subjected to four different conditions: DMEM (control); laser treatment (L-660 nm, 100 mW, 100 J.cm-2); methylene blue treatment (MB-25 µM, 30 min), and MB treatment followed by low-level red laser irradiation (MB-PDT). Groups were evaluated after 24 h. MB-PDT treatment reduced cell viability and migration. However, because MB-PDT did not significantly increase the levels of active caspase-3 and BCL-2, apoptosis was not the primary mode of cell death. MB-PDT, on the other hand, increased the acid compartment by 100% and the LC3 immunofluorescence (an autophagy marker) by 254%. Active MLKL level, a necroptosis marker, was higher in PC3 cells after MB-PDT treatment. Furthermore, MB-PDT resulted in oxidative stress due to a decrease in total antioxidant potential, catalase levels, and increased lipid peroxidation. According to these findings, MB-PDT therapy is effective at inducing oxidative stress and reducing PC3 cell viability. In such therapy, necroptosis is also an important mechanism of cell death triggered by autophagy.

High-lipid nutritional environment in different ontogenetic periods induce developmental programming of rat prostate at aging.

In brief: Maternal obesity plus high-fat diet in breastfeeding induces stromal hyperplasia and diffuse acinar atrophy in the rat prostate at aging, related to dyslipidemia and testosterone reduction. The high-lipid nutritional environment from intrauterine and throughout life favors the development of prostatic intraepithelial neoplasia and aggravated degenerative alterations in the gland. Abstract: Maternal obesity and high-fat diet (HFD) affect permanently prostate histophysiology in adulthood, but the consequences during aging are unknown. Here, we evaluated the prostate alterations in middle-aged rats subjected to a high-lipid nutritional environment (HLE) in different ontogenetic periods. Wistar rats (56 weeks of age) were assigned into groups exposed to standard nutrition (C) or HLE during gestation (G), gestation and lactation (GL), from lactation onward (L), from weaning onward (W) and from gestation onward (AL). HLE in the periods after weaning consisted of HFD (20% fat), and during gestation and lactation it also included previous maternal obesity induced by the HFD. HLE increased total cholesterol and triglyceride levels in all groups and led to insulin resistance in GL and AL and obesity in L. Serum testosterone levels decreased ~67% in GL, ~146% in L and W, and ~233% in AL. Histological and stereological analysis revealed an increment of the stromal compartment and collagen fibers in the prostates of all HLE groups, as well as degenerative lesions, such as cell vacuolation and prostate concretions. HLE aggravated acinar atrophy in G, GL, and L, and in AL it reached more than 50% of the prostate area for most animals. The foci of prostatic intraepithelial neoplasia increased in AL. Tissue expression of androgen receptor did not vary among groups, except for a higher stromal expression for G and GL. Even when restricted to gestation and lactation, HLE induces diffuse acinar atrophy in the aging prostate and worsens degenerative and premalignant lesions when it continues throughout life.

Maternal supplementation with corn oil associated or not with di-n-butyl phthalate increases circulating estradiol levels of gerbil offspring and impairs sperm reserve.

This study evaluated the consequences of gestational exposure to di-n-butyl phthalate (DBP) for testicular steroidogenesis and sperm parameters of the adult gerbil and the interference of corn oil (co), a vehicle widely used for administration of liposoluble agents, on DBP effects. Pregnant gerbils received no treatment or were treated from gestational day 8 to 23 via gavage with 0.1 mL/day of co only or containing DBP (100 mg/kg/day). Maternal co intake enhanced serum estradiol levels and testicular content of ERα, and reduced sperm reserve of adult offspring. Gestational DBP exposure caused dyslipidemia, increased serum and intratesticular estradiol levels and reduced sperm reserve and motility. Thus, maternal co supplementation alters circulating estradiol and impairs sperm quantity and quality of offspring. Gestational DBP exposure alters lipid metabolism and testicular steroidogenesis and worsens the negative effects of co on the sperm reserve and motility of gerbil. Therefore, co interferes with the reproductive response to DBP.

Role of the TNF-α receptor type 1 on prostate carcinogenesis in knockout mice.

BACKGROUND: TNF-α is a key cytokine involved in prostate carcinogenesis and is mediated by the TNF-α receptor type 1 (TNFR-1). This receptor triggers two opposite pathways: cell death or cell survival and presents a protective or stimulator role in cancer. Thus, the purpose of this study was to evaluate the role of TNF signaling in chemically induced prostate carcinogenesis in mice. METHODS: C57bl/6 wild type (WT) and p55 TNFR-1 knockout mice (KO) were treated with mineral oil (control) or N-methyl N-nitrosurea (MNU) in association with testosterone (MNU+T, single injection of 40 mg/kg and weekly injection 2 mg/kg, respectively) over the course of 6 months. After this induction period, prostate samples were processed for histological and biochemical analysis. RESULTS: MNU+T treatment led to the development of prostate intraepithelial neoplasia (PIN) and adenocarcinoma (PCa) in both WT and KO animals; however, the incidence of PCa was lower in KO group than in WT. Cell proliferation analysis showed that PCNA levels were significantly lower in the KO group, even after carcinogenesis induction. Furthermore, the prostate of KO animals had lower levels of p65 and p-mTOR after treatment with MNU+T than WT. There was also a decrease in prostate androgen receptor levels after induction of carcinogenesis in both KO and WT mice. Regarding the extracellular matrix in the prostate, KO mice had higher levels of fibronectin and lower levels of matrix metalloproteinase 2 (MMP2) after carcinogenesis. Finally, there was a similar increase in apoptosis in both groups after carcinogenesis, indicating that the TNAFr1 pathway in prostate carcinogenesis presented proliferative, and not apoptotic, stimuli. CONCLUSIONS: TNF-α, through its receptor TNFR-1, promoted cell proliferation and cell survival in prostate by activation of the AKT/mTOR and NFKB pathway, which stimulated prostate carcinogenesis in chemically induced mice. Prostate 76: 917-926, 2016. © 2016 Wiley Periodicals, Inc.

Differential ontogenetic exposure to obesogenic environment induces hyperproliferative status and nuclear receptors imbalance in the rat prostate at adulthood.

BACKGROUND: Experimental data indicate that high-fat diet (HFD) may alter proliferative activity and prostate health. However, the consequences of HFD exposure during different periods of ontogenetic development on prostate histophysiology remain to be elucidated. Herein, we compare the influence of obesogenic environment (OE) due to maternal obesity and HFD at different periods of life on proliferative activity and nuclear receptors frequency in the rat ventral prostate and a possible relationship with metabolic and hormonal alterations. METHODS: Male Wistar rats (19 weeks old), treated with balanced chow (Control group-C; 3% high-fat, 3.5 Kcal/g), were compared with those exposed to HFD (20% high-fat, 4.9 kcal/g) during gestation (G-maternal obesity), gestation and lactation (GL), from post-weaning to adulthood (WA), from lactation to adulthood (LA) and from gestation to adulthood (GA). After the experimental period, the ventral prostate lobes were removed and analyzed with different methods. RESULTS: Metabolic data indicated that G and GL rats became insulin resistant and WA, LA, and GA became insulin resistant and obese. There was a strong inverse correlation between serum testosterone (∼133% lower) and leptin levels (∼467% higher) in WA, LA, and GA groups. Estrogen serum levels increased in GA, and insulin levels increased in all groups, especially in WA (64.8×). OE-groups exhibited prostatic hypertrophy, since prostate weight increased ∼40% in G, GL, LA, and GA and 31% in WA. As indicated by immunohistochemistry, all HFD-groups except G exhibited an increase in epithelial cell proliferation (PCNA-positive) and a decrease in frequency of AR- and ERß-positive epithelial cells; there was also an increment of ERα-positive stromal cells in comparison with control. Cells containing PPARγ increased in both epithelium and stroma of all OE groups and those expressing LXRα decreased, particularly in groups OE-exposed during gestation (G, GL and GA). CONCLUSIONS: OE leads to prostate hypertrophy regardless of the period of development and, except when restricted to gestation, leads to a hyperproliferative status which was correlated to downregulation of AR and LXRα and upregulation of ERα and PPARγ signaling.

Sexual maturation of the Mongolian gerbil (Meriones unguiculatus): a histological, hormonal and spermatic evaluation.

This study determined the phases of sexual development of the male Mongolian gerbil (Meriones unguiculatus) based on an integrative analysis of testicular morphology, hormonal data and sperm parameters. Male gerbils were analysed at 1, 7, 14, 21, 28, 35, 42, 50, 60, 70, 90, 100 and 120 days of age. Body, testicular and epididymal weights increased up to Day 70, 60 and 90, respectively. The impuberal phase, characterised by the presence of gonocytes, extended until Day 14. The prepubertal period lasted until Day 42, when puberty was achieved and a drastic increase in serum testosterone levels, mature adult Leydig cells and elongated spermatids was observed. Gerbils at 60 days of age showed a remarkable number of spermatozoa in the testis, epididymidis caput/corpus and cauda, and at Day 70 the maximum daily sperm production was reached. However, the gerbil may be considered sexually mature only from Day 90 onward, when sperm reserves become stable. The total transit time of spermatozoa along the epididymis of sexually mature gerbils was 11 days, with 1 day in the caput/corpus and 10 days in the cauda. These data cover a lacuna regarding the reproductive parameters of this rodent and provide foundations for its use in testicular toxicology studies.

Histopathological alterations in the prostates of Mongolian gerbils exposed to a high-fat diet and di-n-butyl phthalate individually or in combination.

Both high-fat diet and exposure to endocrine-disrupting chemicals have been implicated in susceptibility to pathological prostate lesions, but the consequences of combining the two have not yet been examined. We evaluated the effects of gestational and postnatal exposure to a high-fat diet (20% fat) and low doses of di-n-butyl phthalate (DBP; 5mg/kg/day), individually or in combination, on the tissue response and incidence of pathological lesions in the ventral prostate of adult gerbils. Continuous intake of a high-fat diet caused dyslipidemia, hypertrophy, and promoted the development of inflammatory, premalignant and malignant prostate lesions, even in the absence of obesity. Life-time DBP exposure was obesogenic and dyslipidemic and increased the incidence of premalignant prostate lesions. Combined exposure to DBP and a high-fat diet also caused prostate hypertrophy, but the effects were less severe than those of individual treatments; combined exposure neither induced an inflammatory response nor altered serum lipid content.

Prostate hyperplasia caused by long-term obesity is characterized by high deposition of extracellular matrix and increased content of MMP-9 and VEGF.

Recent studies have shown a positive association of cancer and obesity, but the morphological and molecular mechanisms involved in this relationship are still unknown. This study analysed the impact of long-term obesity on rat prostate, focusing on stromal changes. Male adult Wistar rats were treated with high-fat diet to induce obesity, while the control group received a balanced diet. After 30 weeks of feeding, the ventral prostate was analysed by immunohistochemistry for cell proliferation, smooth muscle α-actin, vimentin, chondroitin sulphate and metalloproteinases (MMP-2 and 9). The content of androgen receptor (AR), oestrogen receptors (ERs) and vascular endothelial growth factor (VEGF) was measured by Western blotting, and activity of catalase and Glutathione-S-Transferase (GST) were quantified by enzymatic assay. Long-term obesity decreased testosterone plasma levels by 70% and resulted in stromal prostate hyperplasia, as evidenced by increased collagen fibres. Such stromal hyperplasia was associated with increased number of blood vessels and raised VEGF content, and increased expression of chondroitin sulphate, vimentin, α-actin and MMP-9. In spite of the high cell density in prostate, the proliferative activity was lower in the prostates of obese rats, indicating that hyperplasia was established during the early phases in this obesity model. AR levels increased significantly, whereas the ERα decreased in this group. Moreover, the levels of catalase and GST were changed considerably. These findings indicate that long-term obesity, besides disturbing the antioxidant control, causes intense stromal remodelling and release of factors that create an environment that can promote proliferative disorders in the gland, culminating with diffuse hyperplasia.