Background All-trans retinoic acid （ATRA） can influence the tumor cell proliferation cycle, and some chemotherapeutic drugs are cycle specific. In this study, we hypothesize that ATRA can enhance chemotherapeutic dr...Background All-trans retinoic acid （ATRA） can influence the tumor cell proliferation cycle, and some chemotherapeutic drugs are cycle specific. In this study, we hypothesize that ATRA can enhance chemotherapeutic drug sensitivity by affecting the cell cycle of tumor cells.Methods The cell cycle of LoVo cells was evaluated using flow cytometry （FCM）. Cell viability was analyzed using the MTT assay. The morphologic changes in the treated LoVo cells were measured with acridine orange （AO）/ethidium bromide （EB） staining. Expression of survivin in LoVo cells was analyzed by immunofluorescence assay.Results After LoVo cells were treated with ATRA, the G0/G1 ratio of the tumor cells increased and the cell ratio of S-and G2/M-phase decreased. Viability of the cells decreased significantly after combined treatment with ATRA and 5-fluorouracil （5-FU） or mitomycin c （MMC） and was evaluated by fluorescence microscopy. Expression level of survivin in the tumor cells decreased after ATRA combination treatment.Conclusions ATRA enhances drug sensitivity of the LoVo cell line to cell cycle-specific agents and inhibits the expression of survivin in LoVo cells. The combination of ATRA and 5-FU or MMC promoted cell apoptosis, and the mechanism involved in apoptosis may be related to inhibition of survivin gene expression.展开更多
AIM To identify potential anti-cancer constituents in natural extracts that inhibit cancer cell growth and migration. METHODS Our experiments used high dose thymoquinone (TQ) as an inhibitor to arrest LoVo (a human co...AIM To identify potential anti-cancer constituents in natural extracts that inhibit cancer cell growth and migration. METHODS Our experiments used high dose thymoquinone (TQ) as an inhibitor to arrest LoVo (a human colon adenocarcinoma cell line) cancer cell growth, which was detected by cell proliferation assay and immunoblotting assay. Low dose TQ did not significantly reduce LoVo cancer cell growth. Cyclooxygenase 2 (COX-2) is an enzyme that is involved in the conversion of arachidonic acid into prostaglandin E2 (PGE2) in humans. PGE2 can promote COX-2 protein expression and tumor cell proliferation and was used as a control. RESULTS Our results showed that 20 mu mol/L TQ significantly reduced human LoVo colon cancer cell proliferation. TQ treatment reduced the levels of p-PI3K, p-Akt, p-GSK3 beta, and beta-catenin and thereby inhibited the downstream COX-2 expression. Results also showed that the reduction in COX-2 expression resulted in a reduction in PGE2 levels and the suppression of EP2 and EP4 activation. Further analysis showed that TG treatment inhibited the nuclear translocation of beta-catenin in LoVo cancer cells. The levels of the cofactors LEF-1 and TCF-4 were also decreased in the nucleus following TQ treatment in a dose-dependent manner. Treatment with low dose TQ inhibited the COX-2 expression at the transcriptional level and the regulation of COX-2 expression efficiently reduced LoVo cell migration. The results were further verified in vivo by confirming the effects of TQ and/or PGE2 using tumor xenografts in nude mice. CONCLUSION TQ inhibits LoVo cancer cell growth and migration, and this result highlights the therapeutic advantage of using TQ in combination therapy against colorectal cancer.展开更多
基金The work was supported by Natural Science Foundation of Guangdong （No. 06021350）. Acknowledgements： We thank LIU Yang of the Duke University Medical Center in the United States for proofreading.
文摘Background All-trans retinoic acid （ATRA） can influence the tumor cell proliferation cycle, and some chemotherapeutic drugs are cycle specific. In this study, we hypothesize that ATRA can enhance chemotherapeutic drug sensitivity by affecting the cell cycle of tumor cells.Methods The cell cycle of LoVo cells was evaluated using flow cytometry （FCM）. Cell viability was analyzed using the MTT assay. The morphologic changes in the treated LoVo cells were measured with acridine orange （AO）/ethidium bromide （EB） staining. Expression of survivin in LoVo cells was analyzed by immunofluorescence assay.Results After LoVo cells were treated with ATRA, the G0/G1 ratio of the tumor cells increased and the cell ratio of S-and G2/M-phase decreased. Viability of the cells decreased significantly after combined treatment with ATRA and 5-fluorouracil （5-FU） or mitomycin c （MMC） and was evaluated by fluorescence microscopy. Expression level of survivin in the tumor cells decreased after ATRA combination treatment.Conclusions ATRA enhances drug sensitivity of the LoVo cell line to cell cycle-specific agents and inhibits the expression of survivin in LoVo cells. The combination of ATRA and 5-FU or MMC promoted cell apoptosis, and the mechanism involved in apoptosis may be related to inhibition of survivin gene expression.
基金Supported by Grants from the National Natural Science Foundation of China,No.81260364,No.81270472 and No.81070310the"Chunhui"Program of Ministry of Education in China,No.Z2012007the Natural Science Foundation of Inner Mongolian Autonomous Region,No.2012MS1123 and No.2013MS1132
文摘AIM: To investigate the effects of osteopontin (OPN) gene expression knockdown on colon cancer Lovo cells in vitro.
基金Supported by (in part) the Taiwan Ministry of Health and Welfare Clinical Trial and Research Center of Excellence,No.MOHW105-TDU-B-212-133019
文摘AIM To identify potential anti-cancer constituents in natural extracts that inhibit cancer cell growth and migration. METHODS Our experiments used high dose thymoquinone (TQ) as an inhibitor to arrest LoVo (a human colon adenocarcinoma cell line) cancer cell growth, which was detected by cell proliferation assay and immunoblotting assay. Low dose TQ did not significantly reduce LoVo cancer cell growth. Cyclooxygenase 2 (COX-2) is an enzyme that is involved in the conversion of arachidonic acid into prostaglandin E2 (PGE2) in humans. PGE2 can promote COX-2 protein expression and tumor cell proliferation and was used as a control. RESULTS Our results showed that 20 mu mol/L TQ significantly reduced human LoVo colon cancer cell proliferation. TQ treatment reduced the levels of p-PI3K, p-Akt, p-GSK3 beta, and beta-catenin and thereby inhibited the downstream COX-2 expression. Results also showed that the reduction in COX-2 expression resulted in a reduction in PGE2 levels and the suppression of EP2 and EP4 activation. Further analysis showed that TG treatment inhibited the nuclear translocation of beta-catenin in LoVo cancer cells. The levels of the cofactors LEF-1 and TCF-4 were also decreased in the nucleus following TQ treatment in a dose-dependent manner. Treatment with low dose TQ inhibited the COX-2 expression at the transcriptional level and the regulation of COX-2 expression efficiently reduced LoVo cell migration. The results were further verified in vivo by confirming the effects of TQ and/or PGE2 using tumor xenografts in nude mice. CONCLUSION TQ inhibits LoVo cancer cell growth and migration, and this result highlights the therapeutic advantage of using TQ in combination therapy against colorectal cancer.
