Melatonin enhances cell death and suppresses the metastatic capacity of ovarian cancer cells by attenuating the signaling of multiple kinases.

BACKGROUND: Ovarian cancer is a highly aggressive disease that is frequently diagnosed in advanced stages. Melatonin, with its numerous antitumor properties, holds great promise in cancer treatment. Herein, we investigated the effects of melatonin on apoptosis, cell migration, and kinase levels in human ovarian carcinoma SKOV-3 cells and determined whether these effects are mediated by the activation of the MT1 receptor. METHODS: SKOV-3 cells were exposed to different concentrations of melatonin based on the presence of MT1 receptor, and we also performed specific silencing of the melatonin receptor gene MTNR1A. RESULTS: Our findings revealed that melatonin reduced cell viability as shown by the MTT assay, and flow cytometry analysis showed increased rates of apoptosis and necrosis in all melatonin-treated cells. Melatonin significantly decreased the migratory and invasive capacities of the cells. Propidium iodide labeling indicated that melatonin induced cell cycle arrest by reducing DNA content in the S and G2/M phases in SKOV-3 cells. Additionally, the levels of AKT, ERK1/2, JNK, CREB, p70S6K, STAT3/5, and p38 MAP kinase involved in cell survival, proliferation, motility, and stress responses were depressed by melatonin and further reduced after MT1 knockdown. These molecules were found to be associated with lower overall survival in ovarian cancer patients. CONCLUSIONS: Melatonin had obvious oncostatic actions on ovarian cancer cells, and MT1 receptor knockdown intensified its antitumor effect. The inhibition of the MT1 receptor resulted in a substantial reduction in the migratory and invasive capacities of the cells, suggesting its potential as a therapeutic target for the treatment of ovarian cancer.

Citral Modulates MMP-2 and MMP-9 Activities on Healing of Gastric Ulcers Associated with High-Fat Diet-Induced Obesity.

Obesity causes low-grade inflammation that results in the development of comorbidities. In people with obesity, exacerbation of gastric lesion severity and delayed healing may aggravate gastric mucosal lesions. Accordingly, we aimed to evaluate the citral effects on gastric lesion healing in eutrophic and obese animals. C57Bl/6 male mice were divided into two groups: animals fed a standard diet (SD) or high-fat diet (HFD) for 12 weeks. Gastric ulcers were induced using acetic acid (80%) in both groups. Citral (25, 100, or 300 mg/kg) was administered orally for 3 or 10 days. A vehicle-treated negative control (1% Tween 80, 10 mL/kg) and lansoprazole-treated (30 mg/kg) were also established. Lesions were macroscopically examined by quantifying regenerated tissue and ulcer areas. Matrix metalloproteinases (MMP-2 and -9) were analyzed by zymography. The ulcer base area between the two examined periods was significantly reduced in HFD 100 and 300 mg/kg citral-treated animals. In the 100 mg/kg citral-treated group, healing progression was accompanied by reduced MMP-9 activity. Accordingly, HFD could alter MMP-9 activity, delaying the initial healing phase. Although macroscopic changes were undetectable, 10-day treatment with 100 mg/kg citral exhibited improved scar tissue progression in obese animals, with reduced MMP-9 activity and modulation of MMP-2 activation.

The essential oil from Baccharis trimera (Less.) DC improves gastric ulcer healing in rats through modulation of VEGF and MMP-2 activity.

ETHNOPHARMACOLOGICAL RELEVANCE: Baccharis trimera (Less.) DC known as "carqueja" in Brazil has been acknowledged as a medicinal plant in folk medicine for the treatment of stomach aches and gastrointestinal disorders. AIM OF THE STUDY: The present study aimed to evaluate the gastroprotective and healing effects of essential oil from B. trimera (EOBT) against gastric ulcer lesions caused by absolute ethanol and acetic acid, respectively, and to identify the mechanism of action of this essential oil in male Wistar rats. MATERIALS AND METHODS: The plant material used to obtain EOBT was collected in the southern region of Brazil and was analyzed by chromatography-mass spectrometry (GCMS) demonstrate its characteristic chemical composition, with carquejyl acetate as its main component. Different doses of EOBT (50, 100, and 200 mg/kg) were administered orally in male Wistar rats as an acute treatment against absolute ethanol-induced gastric lesions. The gastric healing effect of EOBT (100 mg/kg) was evaluated once a day after 7, 10, and 14 days of treatment. After treatment, the stomachs of rats from all groups were collected to measure the lesion area (mm2), the activity of myeloperoxidase (MPO), and the relative expression of caspases -3, -8, -9, cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF). The zymography method was used to elucidate the activity of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) in the healing action of EOBT. We also analyzed toxicological parameters (body weight evolution and biochemical parameters) that could result after treatment with this essential oil for 14 days. RESULTS: Pretreatment with EOBT (100 and 200 mg/kg) significantly decreased the severity of gastric damage induced by absolute ethanol and decreased MPO activity in gastric tissue. After 10 and 14 days of treatment with EOBT (100 mg/kg) once a day, the lesion area was significantly reduced by 61% and 65.5%, respectively, compared to the negative control group. The gastric healing effect of EOBT was followed by a decrease in the expression of COX-1 compared to that in the negative control group. Notably, treatment with EOBT for 14 days increased the expression of VEGF compared to that using an anti-ulcer drug (lansoprazole). Additionally, analyses of MMP-2 and MMP-9 activities in the gastric mucosa confirmed the accelerated gastric healing effect of EOBT, with a significant decrease in the activity of pro-MMP-2. No sign of toxicity was observed after treatment with EOBT for 14 consecutive days. CONCLUSION: These findings indicated that EOBT was effective in preventing and accelerating ulcer healing by decreasing MPO activity, increasing VEGF expression, and decreasing MMP-2 activity. These actions collectively contribute to the rapid recovery of gastric mucosa following treatment with EOBT, without any observed toxicity.

Systematic Analysis of Monoterpenes: Advances and Challenges in the Treatment of Peptic Ulcer Diseases.

Peptic ulcer disease (PUD) is a multifactorial and complex disease caused by an imbalance of protective and aggressive factors (endogenous and exogenous). Despite advances in recent years, it is still responsible for substantial mortality and triggering clinical problems. Over the last decades, the understanding of PUD has changed a lot with the discovery of Helicobacter pylori infection. However, this disease continues to be a challenge due to side-effects, incidence of relapse from use of various anti-ulcer medicines, and the rapid appearance of antimicrobial resistance with current H. pylori therapies. Consequently, there is the need to identify more effective and safe anti-ulcer agents. The search for new therapies with natural products is a viable alternative and has been encouraged. The literature reports the importance of monoterpenes based on the extensive pharmacological action of this class, including wound healing and anti-ulcerogenic agents. In the present study, 20 monoterpenes with anti-ulcerogenic properties were evaluated by assessing recent in vitro and in vivo studies. Here, we review the anti-ulcer effects of monoterpenes against ulcerogenic factors such as ethanol, nonsteroidal anti-inflammatory drugs (NSAIDs), and Helicobacter pylori, highlighting challenges in the field.