Study On The Development Mechanism Of Human Proline Isomerase CYPJ In Promoting Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in China and typically has poor prognosis, due to the fact that diagnosis is frequently made at an advanced stage. Therefore, development of novel, effective targets and therapies is of prime importance. Many researches have found that cyclophilin A (CYPA), a peptidyl-prolyl cis-trans isomerase, is involved in the promotion of tumor cell proliferation, in particular, the secreted extracellular CYPA. The secreted CYPA protein interacts with its membrane receptor CD 147, and activates the MAPK-ERK1/2 signaling pathway, which eventually promotes the proliferation of tumor.In our previous studies, we have identified a novel member of cyclophilin protein family, named cyclophilin J (CYPJ). The tissue distribution of CYPJ indicated high expression in the liver, and CYPJ mRNA was elevated in 71.42% liver cancer tissue samples. Stable transfection of CYPJ promoted HCC cell growth, and knockdown the expression of CYPJ with RNA interference inhibited HCC cell growth. Further more, CYPJ could promote the transition of cells from G1 to S phase through upregulating of cyclin D1.Based on these findings, we further evaluated the roles of CYPJ in HCC. As same as CYPA, CYPJ was a secreted protein, and shared the same membrane receptor CD147. The exogenous CYPJ protein could promote the proliferation of tumor cells and the transition of cells from G1 to S phase. By interacting with CD 147, the exogenous CYPJ protein could up-regulate ERK signaling pathway in a dose and time dependent manner, and could up-regulate cyclin D1 expresstion.Many researches indicated that cyclophilins might be useful candidate genes for carcinogenesis, and could provide new clues for novel diagnostic and therapeutic agent. Anti-cyclophilin agents might be a promising strategy for treating carcinogenesis. With the program AutoDock Vina and the crystal structure of CYPA/CYPJ, a functional search model for the discovery of new inhibitors of CYPA/CYPJ was formulated. The data of molecular docking showed that (-)-epigallocatechin gallate (EGCG) was one of the compounds with the lowest docked free energy of CYPA/CYPJ, and with higher binding affinity to CYPJ. By targeting CYPJ, EGCG could inhibit the proliferation of tumor cells in vitro and in vivo. Further more, EGCG could inhibit the up-regulation of ERK signaling pathway by the exogenous CYPJ protein, and could down-regulate cyclin D1 expression.Since the anti-tumor activity of EGCG was not optimal, we took the strategy of drug combination and found that EGCG could enhance the effects of Carboplatin, Camptothecin, Doxorubicin, Methotrexate, Mitomycin C, Taxol, Sorafenib, Vincristine and Daunorubicin in HCC cells. The synergy effect of EGCG on Sorafenib could be found in vitro and in vivo.As an inhibitor of CYPA/CYPJ, the anti-tumor effect of FD10 could be observed in vitro and in vivo, but the effect was not optimal. Based on the structure of FD10, a series of 3,4,5-pyrazole-derivatives were synthesized using modifications at the ring C of the pyrazole moiety. The structure-activity relationships (SARs) for this class of compounds demonstrated that different substitutions including methoxy, fluorine group at the para--or meta-position on the phenyl ring C, led to good activity. FD10 and yhhu-990 could dramatically inhibit the replication of HIV-1. FD10 derivatives could inhibit tumor growth in vitro, but yhhu-989 failed to inhibit tumor growth in vivo.In general, CYPJ was a secreted protein and a new ligand of CD 147, which could up-regulate ERK signaling pathway and cyclin D1 expression. We screened several inhibitors of CYPJ based on its structure and found that EGCG could inhibit the proliferation of tumor cells by targeting CYPJ. EGCG could significantly enhance the anti-tumor effect of Sorafinib against HCC. FD10 and its derivatives had anti-tumor effects, while FD10 and yhhu-990 had anti-HIV-1 effects. These inhibitors provide new methods to study the roles of cyclophilins in tumorgenesis and virus replication, and could be modificated to develop more potent anti-tumor and anti-HIV-1 drugs.