Blocking of The Prostaglandin E2 Receptor as a Therapeutic Strategy for Treatment of Breast Cancer: Promising Findings in a Mouse Model.

OBJECTIVE: The study aimed to investigate the anticancer effect of E-prostanoid receptor 1 (EP1) antagonist, SC19220, alone or in combination with the COX-2 inhibitor Celecoxob(CXB)® in mice bearing solid Ehrlich carcinoma (SEC). METHODS: The tumors were induced in 40 female mice, which were divided randomly into four equal groups (n= 10 in each group): Tumor control, CXB, EP1 antagonist, and co-treatment. CXB (10mg/kg) and EP1 antagonist (2mg/kg) were given intraperitoneally every three days, six times in total, then tissue was extracted and prepared for histopathology and measurement of weight, PGE2, and gene expression of EP1 and ß 1 integrin. RESULTS: Both inhibitors, alone or in combination, showed a significant (p<0.001) antitumorigenic effect by decreasing, significantly (p<0.001), each of the tumor weights, tumor volumes, PGE2 levels, EP1 and ß1-integrin gene expression along with increasing, significantly (p<0.001), the P53 tumor suppressor protein. The survival rate was improved from 80% in the control group to reach 100% in the treated groups. The co-treatment by CXB and EP1 antagonist showed a marked decrease in tumor weights and volumes as compared with the single treatment. In parallel, the histopathological findings showed enhanced apoptosis and diminished necrosis in the co-treated group. CONCLUSION: EP1 antagonist proved an antitumorigenic effect alone or combined with CXB and could play a new therapeutic strategy against breast cancer.

Inhibition of PKC/MEK pathway suppresses ß1-integrin and mitigates breast cancer cells proliferation.

Prostaglandin E2 (PGE2) and ß1-integrin have been correlated with breast cancer, where both could enhance progression and metastasis. Protein kinase C (PKC) and MEK have played a vital role in breast cancer development. Our study was conducted to elucidate the effect of inhibition of E-prostanoid receptor 1 (EP1)/ PKC/ MEK/ ß1-integrin pathway in mitigating breast cancer progression and to evaluate the role of the intermediate signals FOXC2, E2F1, NF-Ò¡B and survivin. MCF7 cells were treated with 17 -PT-PGE2, an EP1 agonist, for 24 h, and ß1-integrin was measured. To MCF7 cells treated with 17-PT-PGE2, inhibitors of either EP1, MEK, PKC or NF-Ò¡B were added followed by measurement of ß1-integrin gene expression and cell proliferation in each case. Addition of 17- PT-PGE2 to MCF7 cells showed enhancement of both cell proliferation, and cell cycle transition from G1 to S phase. In addition, activation of EP1 receptor increased ß1-integrin expression. On the contrary, inhibition of EP1 receptor showed a decrease in the cell proliferation, ß1-integrin expression and cells transition to S phase, but increased cell count in apoptotic phase. Selective inhibition of each of MEK, PKC, and NF-Ò¡B suppressed 17 -PT-PGE2-mediated ß1-integrin expression as well as cell proliferation. Furthermore, FOXC2, phosphorylated NF-Ò¡B, E2F1, and survivin levels were upregulated with 17- PT-PGE2 and suppressed by MEK, PKC and NF-Ò¡B inhibitors. Targeting the biochemical mediators of PKC/MEK pathway may be of value in developing new chemical entities for cancer treatment.

Gastroprotective effect of garlic in indomethacin induced gastric ulcer in rats.

OBJECTIVE: Garlic, in its natural plant state, has a great history in ancient medicine as a remedy for many diseases. In our study, the gastroprotective effect of aged garlic extract (AGE) and the possible underlying mechanisms were investigated in an experimental model of indomethacin-induced gastric ulcer. METHODS: Male Wistar rats were divided into four groups: (normal control, n = 20), ulcer control (indomethacin group, n = 20), (omeprazole group, n = 30) and (garlic group, n = 20). Each dose of garlic and omeprazole was given to rats orally daily for 10 consecutive days before induction of ulcer by indomethacin. Indomethacin was given as a single oral dose (100 mg/kg). Four hours later after indomethacin treatment, the rats were sacrificed and gastric tissue was obtained for histopathological examination, calculation of ulcer index and measurement of oxidative stress markers as well as gastroprotective mediators. RESULTS: The results showed that indomethacin induced gastric ulcer (ulcer index = 2900), was associated with a significant increase of tumor necrosis factor-alpha and malondialdehyde, and significant decrease of the gastroprotective mediators prostaglandin E2, glutathione (GSH) and nitric oxide (NO) compared with normal control. Pretreatment with AGE produced comparable results with those obtained in the omeprazole group; the preventive index in the AGE group was 83.4% compared with 94.5% in the omeprazole group. The prophylactic role of AGE in indomethacin-induced ulcer was, in part, mediated by decreasing oxidative stress and increasing gastric level of PGE2, GSH, and NO. CONCLUSION: AGE corrected the histopathological abnormalities in gastric tissue and proved a promising gastroprotective role in gastric ulcer.

Nebivolol prevents indomethacin-induced gastric ulcer in rats.

Gastric ulcer is a very common gastrointestinal disease that may lead to dangerous complications and even death. This study was conducted to evaluate the prophylactic effect of nebivolol against indomethacin [INDO]-induced gastric ulcer. Male Wistar rats were divided into four groups: normal control, ulcer control (INDO only), omeprazole before INDO and nebivolol before INDO. Each rat to receive nebivolol and omeprazole was given the agent orally (by gavage) daily for 10 days prior to induction of ulcer by oral dosing with INDO. Four hours after INDO treatment, all rats were euthanized and their stomachs obtained for measures of gastric acidity, oxidative stress and inflammatory markers, as well as cytoprotective mediators. The results showed that a single oral dose of INDO (100 mg/kg) induced gastric acidity, an ulcer index of 2900 and significantly increased levels of gastric tumor necrosis factor (TNF)-α and malondialdehyde (MDA) and significantly decreased levels of gastric prostaglandin E2 (PGE2), glutathione (GSH) and nitric oxide (NO), compared to in normal control counterpart stomachs. Giving nebivolol before INDO corrected the gastric acidity and resulted in a significant increase in GSH, PGE2 and NO and a significant decrease in TNFα and MDA gastric levels, compared to ulcer control values. Results obtained with nebivolol were comparable to those with omeprazole; the preventive index in the nebivolol group was 90.7% compared to 94.5% in rats in the omeprazole group. These studies showed that nebivolol provided a valuable role in preventing gastric ulcers induced by INDO and provided a promise for potentially protecting hypertensive patients from experiencing gastric ulcer. Thus, it is possible that, pending further studies, nebivolol could be used for pre-exposure prophylaxis from gastric ulcer in these patients.