The Expression Of Retinoic Acid Receptors In Human Ovarian Cancer Cell Line COC2 Treated With All-trans Retinoic Acid

Ovarian cancer has the highest mortality rate among malignancies of thefemale genital tract. By the time of diagnosis, most patients have been advancedstages of the disease. Operation and postoperative chemotherapy for this conditionare still suboptimal. The overall five-year survival rate is only 20-30％, the mostof these patients will die from recurrent cancer and the toxic effect ofchemotherapy drugs. Therefore, ongoing researches focuses on the developmentof more potent therapies. Retinoic acid, a classical cell differentiation agent, hasbeen shown effective in solid tumor, and also has been shown to inhibit growth ofhuman ovarian cancer cells in vitro. This paper focus on the study about all-transretinoic acid inhibiting the growth of human ovarian cancer cells on the level ofreceptors and give a brief exploration about probable mechanism.PartⅠEffects of all-trans retinoic acid on inhibitorycell proliferation and induction of differentiatin in humanovarian cancer cell line COC2. Objective To investigate the effects ofall-trans retinoic acid (ATRA) oninhibitory cell proliferation and inducting differentiation in human ovarian cancercell line COC2.Methods All the 30 bottles of ovarian cancer cells with the same celldensity were divided into six treatment groups by random, 1) control, 2-6) groupswere treated respectively at different ATRA concentrations ranged from ATRA 1,5,10,20 to 30μmol/L, every group consist of 5 bottles cells, all the cells of the sixgroups were cultured in the same conditions and evaluated separately by 1) directcell counts, 2) cell morphological changes observation by inverted microscope. 3)cell morphological changes observation by electronic microscope.Results 1. Cell growth inhibition occurred in COC2 cell lines in a doseand time-dependent manner within a certain concentration ranged in ATRA 1-20μmol/L. 2. Cell growth overlapping was observed in control group and ATRA 1μmol/L group by inverted microscope after 72 hours; cell density was graduallydecreased within a certain concentration ranged in ATRA 1-20μmol/L and celldebris was observed gradually increased in the ATRA 30μmol/L group and therealmost were no living cells after 72 hours. 3. We observed by electronicmicroscope that the cell morphous was inordinate, cell nucleus was bigger andnucleoli apparente, kytoplasm was small and no glycogen particles in the controlgroup, but in the ATRA 10μmol/L group, we observed that kytoplasm wasincreasing, cell organelle was plentiful and had some glycogen particles, weobserved apoptosis also.Conclusion It is suggested in the present study that ATRA is effectiveagent on inducing differentiation and promoting apoptosis in human ovariancancer cell line COC2 in a certain concentration range from 1 to 201μmol/L in vitro.PartⅡDetection of retinoic acid receptors mRNAexpression in human ovarian cancer cell line COC2 treatedwith ATRA by real time quantitative PCRObjective To detect the expression of retinoic acid receptorsRARer mRNA and RXRαmRNA in human ovarian cancer cell line COC2 treatedwith all-trans retinoic acid(ATRA).Methods All the ovarian cancer cells were divided into two treatmentgroups(A: control, B: ATRA). The B group was treated respectively at differentdrug concentrations with ATRA 1,5,10,20μmol/L, all the cells of the two groupswere cultured in the same conditions. Total RNA was extracted using the Trizolaccording to the manufacturer's instructions after 72 hours, cDNA wassynthesized using MMLV reverse transcriptase, and RARαmRNA andRXRαmRNA of each group were respectively detected using real-time quantitativePCR with the ABI PRISM 7000 Sequence Detection System, then we can knowthe relative quantitations of every group according to all of data.Results 1. We observed that the amplification initiation of RARαmRNA was the latest in the control group from the amplification curve, and it was moreand more early with the concentration of ATRA increasing, the amplificationinitiation of RXRαmRNA was on the contrary. 2. There was favourable linearcorrelation between the initial templete concentration and Ct, it illustrated that thequantitation was accurate and reliable. 3. We detected from the quantitation ofevery group that the expression of RAR mRNA was up regulated and theexpression of RXR mRNA was down regulated after using ATRA with dosedependent manner within a certain concentration rangedConclusion The expression of RAR mRNA in ovarian cancer cellCOC2 was up-regulated after treated with ATRA, and there was statisticalsignificance in the contrast between ATRA 10μmol/L group and control group(P=0.002). The expression of RXR mRNA in ovarian cancer cell line COC2 was onthe contrary, and there all were statislical significance in the contrast between everyconcentration ATRA group and control group (P＜0.001). Therefore, we canconclude that ATRA may be relative to the expression of RAR mRNAup-regulation and RXR mRNA down-regulation in human ovarian canccr ccllline COC2, and produce a inhibit effect to human ovarian cancer cell.