Tempol differential effect on prostate cancer inflammation: In vitro and in vivo evaluation

Evaluation of the effects of Tempol on oxidative stress and angiotensin-II induced hypertension in mice exposed to nicotine from electronic and tobacco cigarettes

Electronic cigarette (E-Cig) is commonly used as an alternative to tobacco cigarette (T-Cig), as it lacks many of the toxicants present in T-Cigs. However, the toxicological mechanisms underlying E-Cig-induced hypertension are not yet well understood. The goal of this research was to explore the effects of Tempol in reducing hypertension caused by T-Cig and E-Cig exposure by mitigating oxidative stress and regulating angiotensin-II production in mouse models subjected to T-Cig and E-Cig smoke. Male C57BL/6 J mice were assigned to eight distinct groups: Air, Air + Tempol, T-Cig, T-Cig + Tempol, NIC-free E-Cig, NIC-free E-Cig + Tempol, E-Cig, and E-Cig + Tempol. Mice exposed to smoking for 12 min per hour, 6 cycles/day, 7 days/week for 4 weeks. Blood pressure was monitored, and Angiotensin-II and cGMP levels were measured using ELISA. Oxidative stress markers (GPx, GSTA1, SOD, MDA, nitrite) were assessed by RT-PCR and biochemical assays. The collected data showed a weight loss with high blood pressure and vasoconstriction in the T-Cig and E-Cig groups. Results showed an induction of angiotensin-II, GPx, GSTA1, SOD, and MDA. In contrast, cGMP and nitrite levels were reduced in the T-Cig and E-Cig groups. Tempol treatment regulated oxidative stress markers, angiotensin-II and cGMP levels, leading to a significant reduction in blood pressure. The results indicate that Tempol is essential in reducing oxidative stress and the effects of angiotensin-II caused by T-Cig and E-Cig exposure, thereby contributing to the regulation of systemic hemodynamic function.

Araticum (Annona crassiflora Mart.) by-products suppress cell proliferation and induce apoptosis particularly in androgen-dependent prostate cancer cell lines

Prostate cancer is the second most diagnosed type of cancer in men. The araticum (Annona crassiflora Mart.) is a fruit found in natural areas of the Brazilian cerrado, and its by-products contain a variety of compounds that have already demonstrated positive effects on cancer. To this end, we evaluated the in vitro antioxidant capacity of the extract of the peel and seed of the A. crassiflora. In addition, we investigated its antiproliferative effects and the possible mechanisms involved in inducing apoptosis in androgen-dependent and androgen-independent prostate cancer cells. The extract of A. crassiflora peel showed a high content of total phenolic compounds, reaching 222.44 mg GAE/g fdw, while the seed recorded a considerably lower value of 26.49 mg GAE/g fdw. These results indicate that the peel has a higher antioxidant capacity compared to the seed, probably due to its high content of phenolic compounds. Both extracts reduced the viability of prostate cancer cells, with the seed proving more effective. The IC50 of the seed extract was significantly lower in the PC-3 cells, presenting an IC50 of 33.24 μg/mL, 30.70 μg/mL and 24.86 μg/mL, for 24, 48 and 72 h respectively, compared to that of the peel. The peel extract showed IC50 of 277 μg/mL, 225 μg/mL and 67.30 μg/mL for the same periods. In 22Rv1 cells, the IC50 of the seed extract showed lower values, presenting IC50 of 12.64 μg/mL, 6.07 μg/mL and 5.12 μg/mL for 24, 48 and 72 h, respectively. However, the peel extract showed IC50 of 77.36 μg/mL, 42.92 μg/mL and 48.16 μg/mL for 24, 48 and 72 h. Both extracts showed a more pronounced effect on LNCaP cells. At 24 h, the IC50 of the seed extract was lower (IC50 of 22.87 μg/mL) than that of the peel extract (IC50 of 47.51 μg/mL) for LNCaP cells. However, after 48 h of treatment, the peel extract showed a decrease in IC50 of 17.64 μg/mL and the seed extract 21.13 μg/mL. However, after 72 h the seed extract was more effective in reducing cell viability with an IC50 of 6.51 μg/mL in contrast the peel showed IC50 of 11.50 μg/mL. The seed extract had a significant effect on apoptosis induction in LNCaP, increasing the protein levels of Bax, procaspase-3, caspase-9 and caspase-8, while reducing Bcl-2 and Bcl-xL expression. The seed extract also decreased the androgen receptor and PCNA levels in 22Rv1 and LNCaP cells, suggesting a possible antiproliferative mechanism mediated by the modulation of these proteins.

MiRNAs and tempol therapeutic potential in prostate cancer: a preclinical approach

This study investigated tempol action on genes and miRNAs related to NFκB pathway in androgen dependent or independent cell lines and in TRAMP model in the early and late-stages of cancer progression. A bioinformatic search was conducted to select the miRNAs to be measured based on the genes of interest from NFκB pathway. The miR-let-7c-5p, miR-26a-5p and miR-155-5p and five target genes (BCL2, BCL2L1, RELA, TNF, PTGS2) were chosen for RT-PCR and gene enrichment analyses. In vitro, PC-3 and LNCaP cells were exposed, respectively, to 1.0 or 2.0 mM of tempol during 48 h. In vivo, five experimental groups were evaluated regarding tempol effects in the early (CT12 and TPL12 groups) and late-stages (CT20, TPL20-I and TLP20-II) of PCa development. TPL groups were treated with 50 mg/kg or 100 mg/kg of tempol. The ventral lobe of the prostate and the plasma was collected. Tempol treatment increased miRs expression in PC-3 and LNCaP. For both cell lines, tempol decreased RELA expression. In TRAMP model, tempol increased miRNA expression in prostate for all treated groups. Tempol upregulated the miRNA expressions related to the NFκB pathway in the prostate tissue and human tumor cell lines. Their increase is mainly linked to increased cell death and delayed CaP aggressivenes. Thus, tempol's capacity for miRNA-mediated gene silencing to decrease tissue proliferation and cell survival processes is part of its tissue mechanics.

Tempol mitigates inflammation, oxidative stress, and histopathological alterations of cadmium-induced parotid gland injury in rats

Cadmium (Cd) is a potent environmental pollutant that causes functional and structural damage to the salivary glands. Tempol (TEM) has powerful antioxidant activity that can potentially preserve organ function.

AIMS

This study was designed to investigate the protective effects of TEM on Cd-induced toxicity in rat parotid salivary glands.

MATERIALS AND METHODS

Twenty-four adult Wistar male rats were randomly assigned to four equal groups: control, TEM (27.5 g/100 ml), Cd (0.6 g/100 ml), and TEM plus Cd (at the same doses). All treatments were dissolved in distilled water and administered subcutaneously four times a week for four weeks. Parotid gland tissues were isolated and subjected to molecular and histo-biochemical assessments.

KEY FINDINGS

TEM exerted a prophylactic effect against Cd-induced toxicity in the parotid glands by controlling inflammation through the downregulation of toll-like receptor 4/myeloid differentiation primary response 88/nuclear factor kappa B/ interleukin-1 beta mRNA expression, upregulation of aquaporin-5 mRNA expression, improvement of the oxidant/antioxidant status in the parotid gland, mitigation of endoplasmic reticulum stress, and repair of the associated histological and ultrastructural abnormalities.

SIGNIFICANCE

TEM protects against Cd-induced toxicity in the parotid glands of rats, attributable at least in part to its anti-inflammatory and antioxidant properties, as well as its ability to inhibit ER stress and facilitate glandular repair. However, the protective effects of TEM did not reach the levels observed in the control group. TEM could be a promising clinical candidate for protecting the salivary glands, particularly in high-risk groups such as workers exposed to Cd and cigarette smokers.

Differential tempol effects in prostatic cancer: angiogenesis and short- and long-term treatments

Prostate cancer (PCa) is the second cause of cancer death among men worldwide. Several processes are involved in the development and progression of PCa such as angiogenesis, inflammation and oxidative stress. The present study investigated the effect of short- or long-term Tempol treatment at different stages of prostate adenocarcinoma progression, focusing on angiogenic, proliferative, and stromal remodeling processes in TRAMP mice. The dorsolateral lobe of the prostate of TRAMP mice were evaluated at two different stages of PCa progression; early and late stages. Early stage was again divided into, short- or long-term. 50 mg/kg Tempol dose was administered orally. The results demonstrated that Tempol mitigated the prostate histopathological lesion progressions in the TRAMP mice in all treated groups. However, Tempol increased molecules involved in the angiogenic process such as CD31 and VEGFR2 relative frequencies, particularly in long-term treatment. In addition, Tempol upregulated molecule levels involved in angiogenesis and stromal remodeling process VEGF, TGF-β1, VE-cadherin and vimentin, particularly, in T8-16 group. Thus, it was concluded that Tempol treatment delayed prostatic lesion progression in the dorsolateral lobe of the TRAMP mice. However, Tempol also led to pro-angiogenic effects and glandular stromal microenvironment imbalance, especially, in the long-term treatment.

Tempol effect on oxidative and mitochondrial markers in preclinical models for prostate cancer

Background

Tempol is a redox-cycling nitroxide considered a potent antioxidant. The present study investigated the tempol effects on oxidative stress and mitochondrial markers on prostate cancer (PCa).

Methods

PC-3 and LnCaP cells were exposed to tempol. Cell viability test, western blot and Amplex Red analyses were performed. In vivo, five experimental groups evaluated tempol effects in the early (CT12 and TPL12 groups) and late stages (CT20, TPL20-I, and TLP20-II) of PCa development. The TPL groups were treated with 50 or 100 mg/kg tempol doses. Control groups received water as the vehicle. The ventral lobe of the prostate and the blood were collected and submitted to western blotting or enzymatic activity analyses.

Results

In vitro, tempol decreased cell viability and differentially altered the H2O2 content for PC-3 and LNCaP. Tempol increased SOD2 levels in both cell lines and did not alter Catalase protein levels. In vivo, tempol increased SOD2 levels in the early stage and did not change Catalase levels in the different PCa stages. Systemically, tempol decreased SOD2 levels in the late-stage and improved redox status in the early and late stages, which was confirmed by reduced LDH in tempol groups. Alterations on energetic metabolism and oxidative phosphorylation were observed in TRAMP model.

Conclusion

Tempol can be considered a beneficial therapy for PCa treatment considering its antioxidant and low toxicity properties, however the PCa progression must be evaluated to get successful therapy.

The Cellular and Organismal Effects of Nitroxides and Nitroxide-Containing Nanoparticles

Nitroxides are stable free radicals that have antioxidant properties. They react with many types of radicals, including alkyl and peroxyl radicals. They act as mimics of superoxide dismutase and stimulate the catalase activity of hemoproteins. In some situations, they may exhibit pro-oxidant activity, mainly due to the formation of oxoammonium cations as products of their oxidation. In this review, the cellular effects of nitroxides and their effects in animal experiments and clinical trials are discussed, including the beneficial effects in various pathological situations involving oxidative stress, protective effects against UV and ionizing radiation, and prolongation of the life span of cancer-prone mice. Nitroxides were used as active components of various types of nanoparticles. The application of these nanoparticles in cellular and animal experiments is also discussed.