Effect Of Polyunsaturated Fatty Acids DHA On Prostate Cancer Cells LNCap

ObjectiveProstate cancer(prostatic carcinoma,prostatic cancer,PCa)is a common disease in elderly men,the first incidence rate of cancer in the United States,accounting for the second cause of death in men.In China.PCa incidence rate is also increased year by year.PCa is an androgen-dependent malignancy cancer.It is reported that Long-chain co-3 PUFAs such as DHA,EPA can inhibit the growth of prostate cancer cells,but the specific molecular mechanism is unknown.Androgens play an important role in proliferation,differentiation,maintenance and function of the prostate.Androgen receptor(androgen receptor.AR)is the important medium of androgen.In addition to its physiological function,AR plays an important role in the formation of prostate cancer.Therefore,in this study,LNCaP cells are used to investigate whether DHA can inhibit the function of AR in LNCaP cells and reveal the molecular biological mechanisms of DHA inhibited proliferation of LNCaP cells,Our research will provide primary evidence for prvention and treatment of prostate cancer with PUFAs.MethodsA.The role of DHA on the proliferation of LNCaP cell lines was measured by MTT assay.B.The changes of AR expression of LNCaP treated with moderate dose of DHA(30μmol}/L)were measured by Real-time PCR and Western Blot.C.After CHX(a regeant inhibited the process of protein translation)was added,the AR expression of LNCaP treated with high dose of DHA(50 μmo/L)was studied by Western Blot.ResultsA.Cytotoxicity assay showed that when the DHA is 5μmol/L,it starts to inhibit the cell proliferation of the LNCaP.In a certain range of concentration,the inhibition was enhanced as the increasing of concentration.B.According to the results of AR mRNA levels with moderate dose of DHA(30μmol/L)by Real time PCR,it is showed that DHA inhibit the mRNA transcription of AR in LNCaP cell.The AR mRNA levels almostly decresed by 44%compared with control group.C.Expression of AR in LNCaP cell treated with moderate dose of DHA(30μmol/L)was detected Western Blot,The results showed that.DHA inhibit the protein translation of AR in LNCaP cell.The AR protein expression decreased significantly compared with control group.D.After added CHX,the AR expression showed that AR protein expression was already reduced after incubation with DHA for 10h,but it is not obvious time-dependent.And the action of inhibition in new protein synthesis is effective after adding CHX for 48h,45%AR protein were degradation.It shows that compared to protein degradation,DHA inhibits AR protein expression is important.ConclusionsA.DHA can inhibit the cell proliferation of the LNCaP.In a certain range of concentration,the inhibition was enhanced as the increasing of concentration.B.Accoring to the results,DHA inhibit the mRNA transcription and protein translation of AR.The decress of AR expression is due to reduce protein degradation rather than inhibit protein translation process.However,further researches are required to confirm the molecular mechanmis on mRNA level.C.Next,we will also study the signaling pathways of AR and other polyunsaturated fatty acids on the mechanism of prostate cancer,the topic provide a preliminary evidence for the expansion of DHA in the clinical prevention and treatment of prostate cancer.D.We hypothesized that DHA cause protein degradation through the ubiquitin-proteasome pathway,which requires further study.