Objective: Prostaglandin E2 (PGE2) plays a crucial role in regulating bone cell differentiation and proliferation. The aim of the present study was to determine whether PGE2 may regulate osteoblast proliferation induc...Objective: Prostaglandin E2 (PGE2) plays a crucial role in regulating bone cell differentiation and proliferation. The aim of the present study was to determine whether PGE2 may regulate osteoblast proliferation induced by hydroxyapatite. Materials and Methods: Osteoblasts (HOS cell line) pre-treated with cyclooxygenase (COX) inhibitors (indomethacin, aspirin and nimesulide) were then cultured. The cells were also pre-treated with or without nimesulide and then cultured with PGE2. The cell cultures were also treated with SQ22536 (adenylyl cyclase inhibitor) and added with Db-cAMP (cAMP analog), and/or PGE2. KT5720 [protein kinase A (PKA) inhibitor.], Db-cAMP and/or forskolin (adenylyl cyclase activator)-treated cultures were used to assess the role of PKA. The role of EP2 and/or EP4 was determined by using EP2 antagonist (PF-04418948) and EP4 antagonist (L-161,982) with PGE2. All cells were cultured with or without hydroxyapatite. The levels of PGE2 and cAMP were detected from the culture supernantants and the cell proliferation was assessed colorimetrically. Results: Nimesulide and indomethacin but not aspirin suppressed partially the cell proliferation but fully PGE2 production. PGE2 abrogated nimesulide-mediated suppression of cell proliferation. The cell proliferation was enhanced by low but suppressed by high concentration of PGE2. Moreover, the SQ22536-mediated suppression of cell proliferation was abolished by Db-cAMP but not PGE2. Conversely, PGE2, Db-cAMP or forskolin failed to eliminate KT5720-mediated suppression of cell proliferation. The effect of PGE2 on cell proliferation and cAMP levels was mediated predominantly via EP2 and to a lesser extent, EP4. The results of the controls for all experiments were significantly lower than hydroxyapatite-stimulated cell cultures. Conclusion: These results suggest thatPGE2, acting via a COX-2-, cAMP-PKA- and both EP2 and EP4-dependent pathway may partially regulate hydroxyapatite-induced human osteoblasts in an autocrine fashion.展开更多
In recent years the use of natural supplements in order to prevent, treat or delay recurrence of cancer or reduce chemotherapy toxicity has attracted much?attention. One such supplement is Capsol-T which consists of d...In recent years the use of natural supplements in order to prevent, treat or delay recurrence of cancer or reduce chemotherapy toxicity has attracted much?attention. One such supplement is Capsol-T which consists of de-caffeinated green tea and chili pepper extracts. The aim of the study was the evaluation of Capsol-T effect on the proliferation of various cancer cell lines representing different cancer types. Cell lines that were used in the study were: DU145, LNCap,?MCF7, HCT116 and MOR. The effect of various concentrations and incubation times of Capsol-T on cell viability was determined using the MTT method. The results do not show a common anti-proliferative pattern in all cancer cells.?In some cell lines and certain concentrations cell growth was significantly decreased at 24 hr which became more evident at 48?hr. The role of Capsicum?powder in cancer is unclear since both cancer cell proliferation and growth arrest have been demonstrated. Green tea on the other hand was found to decrease certain drugs’ bioavailability. Our results suggest that an anti-proliferative?effect in certain types of cancer should not be generalized to other types as well.?Different concentrations also affect the net result often having opposite effects. Overall, caution should be taken when using natural supplements for their anti-cancer effects.展开更多
文摘Objective: Prostaglandin E2 (PGE2) plays a crucial role in regulating bone cell differentiation and proliferation. The aim of the present study was to determine whether PGE2 may regulate osteoblast proliferation induced by hydroxyapatite. Materials and Methods: Osteoblasts (HOS cell line) pre-treated with cyclooxygenase (COX) inhibitors (indomethacin, aspirin and nimesulide) were then cultured. The cells were also pre-treated with or without nimesulide and then cultured with PGE2. The cell cultures were also treated with SQ22536 (adenylyl cyclase inhibitor) and added with Db-cAMP (cAMP analog), and/or PGE2. KT5720 [protein kinase A (PKA) inhibitor.], Db-cAMP and/or forskolin (adenylyl cyclase activator)-treated cultures were used to assess the role of PKA. The role of EP2 and/or EP4 was determined by using EP2 antagonist (PF-04418948) and EP4 antagonist (L-161,982) with PGE2. All cells were cultured with or without hydroxyapatite. The levels of PGE2 and cAMP were detected from the culture supernantants and the cell proliferation was assessed colorimetrically. Results: Nimesulide and indomethacin but not aspirin suppressed partially the cell proliferation but fully PGE2 production. PGE2 abrogated nimesulide-mediated suppression of cell proliferation. The cell proliferation was enhanced by low but suppressed by high concentration of PGE2. Moreover, the SQ22536-mediated suppression of cell proliferation was abolished by Db-cAMP but not PGE2. Conversely, PGE2, Db-cAMP or forskolin failed to eliminate KT5720-mediated suppression of cell proliferation. The effect of PGE2 on cell proliferation and cAMP levels was mediated predominantly via EP2 and to a lesser extent, EP4. The results of the controls for all experiments were significantly lower than hydroxyapatite-stimulated cell cultures. Conclusion: These results suggest thatPGE2, acting via a COX-2-, cAMP-PKA- and both EP2 and EP4-dependent pathway may partially regulate hydroxyapatite-induced human osteoblasts in an autocrine fashion.
文摘In recent years the use of natural supplements in order to prevent, treat or delay recurrence of cancer or reduce chemotherapy toxicity has attracted much?attention. One such supplement is Capsol-T which consists of de-caffeinated green tea and chili pepper extracts. The aim of the study was the evaluation of Capsol-T effect on the proliferation of various cancer cell lines representing different cancer types. Cell lines that were used in the study were: DU145, LNCap,?MCF7, HCT116 and MOR. The effect of various concentrations and incubation times of Capsol-T on cell viability was determined using the MTT method. The results do not show a common anti-proliferative pattern in all cancer cells.?In some cell lines and certain concentrations cell growth was significantly decreased at 24 hr which became more evident at 48?hr. The role of Capsicum?powder in cancer is unclear since both cancer cell proliferation and growth arrest have been demonstrated. Green tea on the other hand was found to decrease certain drugs’ bioavailability. Our results suggest that an anti-proliferative?effect in certain types of cancer should not be generalized to other types as well.?Different concentrations also affect the net result often having opposite effects. Overall, caution should be taken when using natural supplements for their anti-cancer effects.