Preliminary Study Of TFDP3 In Regulating The Autophagy And Apoptosis Of LNCAP Cell

Prostate cancer(PCa) is one of the malignant tumor and it is second only to lung cancer in male tumor. A large part of patients were diagnosed in the middle and late period duing to the occuring mostly hidden of prostate cancer, and finally the prognosis was poor. The general way of treating prostate cancer is reducing the androgen level, so as to induce the apoptosis of tumor cells. This treatment at an early stage was effective, but after a period of time almost all of the patients were changed from androgen-dependent prostate cancer into the androgen-independent prostate cancer, which eventually leaded to the progression or metastasis of tumor. The mechanisms of the androgen-dependent prostate cancer changing into the androgen-independent prostate cancer have attracted much attention. The known mechanisms including the androgen receptor(AR) mutations, clonal selection, total activation factor(Coactivator) expression and so on. The objective of all the above mechanisms is to avoid prostate cancer cell apoptosis. The present study showed that the autophagy is the main way of degrading the organelles, on certain conditions, the autophagy may play a protective role in the cell apoptosis and inhibiting cell autophagy may induce the apoptosis of cells. Also inhibiting the pathways of cell apoptosis may cause autophagic cell death. There is no clear evidence on whether the androgen has regulation relationship with autophagy in the prostate, or whether the autophagy has relationship with apoptosis in the prostate.TFDP3 is a newly discovered factor which direct regulate E2F1. The studies have shown that TFDP3 not only can inhibit the cell proliferation induced by E2F1, but also can suppress the cell apoptosis induced by E2F1. But there needs to be more research and further validation on whether TFDP3 has the autophagy role in prostate cancer.The expression of TFDP3 in prostate cancer organizations was explored by immunohistochemistry and situ hybridization; the expression of TFDP3 in prostate cancer cells was detected by semi-quantitative RT-PCR. We validated that TFDP3 expressed in prostate cancer, and then gone to the next step research, explored the change of the autophagy related LC3 B gene and the protein level by RT-PCR and Western blot when after the TFDP3 acted on E2F1. And we detected the interaction TFDP3 and E2F1 on the effects in the apoptosis of prostate cancer cell by using flow cytometry instrument.The main research contains:1. First of all, searching the DNA sequence of TFDP3 gene through the NCBI genome database and designing primers by using the software Primer 5.0. Using prostate cancer LNCaP cell genome DNA as template, we amplifying TFDP3 fragments by PCR, approximately 1244 bp. The results showed that the TFDP3 expressed in the prostate cancer cells and tissues.2. After transfection pcDNA3.1-TFDP3 and PCMV-E2F1-HA in the LNCaP cell, the RT-PCR and Western blot test results showed that the expression level of LC3 B in transfection TFDP3 increased significantly, while that in transfection E2F1 plasmid group decreased significantly(P<0.05). All the above indicating that the TFDP3 can induce the expression of autophagy genes LC3 B in LNCaP cells, but the E2F1 can inhibit the expression of autophagy genes LC3 B induced by TFDP3.3. Detecting the change of prostate cancer cells apoptosis after TFDP3 interacting with E2F1 by flow cytometry instrument, we found that cell apoptosis rate increased significantly(P<0.05) after transfection PCMV-E2F1-HA recombinant plasmid, while the apoptosis rate decreased significantly(P<0.05) after transfection PCMV-E2F1-HA with pcDNA3.1-TFDP3. All the above further validated TFDP3 can inhibit the apoptosis induced by E2F1.From above research we can get the following conclusion: TFDP3 can induced the expression of autophagy genes LC3 B in the LNCaP cells, can inhibit the apoptosis induced by E2F1 and play an important role in regulating prostate cancer cells. The results of this study provided new ideas or thoughts on whether TFDP3 can be the target therapy for prostate cancer.