Analysis Of The Role Of Screening-cum-cypa For The Treatment Of Myeloma Kidney Compounds In Small Cell Lung Cancer

The dissertation consists of three parts: the first part describes virtual screening of lead compounds for myeloma kidney based on Iglc structure; the second part describes the identification and structure simulation of D8C, a novel protein domain; the third part describes the expression of Cyclophilin A in lung cancer cells and normal lung cell. The exogeneous CypA protein can stimulate ERK1/2 signal in small cell lung cancer cell, which results in cell's proliferation.In the first part, we performed virtual screening based on the Iglc structure. It is known that binding between Iglc and uromodulin leads to myeloma kidney, the main cause of death in patients with multiple myeloma. We used homology modeling and molecular dynamics to optimize the structure of Iglc, then structure-based virtual screening was used to search for small compounds that could inhibit its binding with uromodulin. According to the binding energy and the characterization of compounds, we have chosen some compounds and tested their effects by pull down method. Three compounds could inhibit the binding. Then we analyzed the binding motif between Iglc and the useful compounds. This may offer guidelines for the rational design of novel drugs that inhibit binding between Iglc and uromodulin for treating myeloma kidney.In the second part, through analyzing uromodulin sequence, we identified a novel domain, D8C (199-289aa), which is present in uromodulin, LZP, GP-2 and cell surface glycoproteins in zebra fish and actinia, etc. These proteins are membrane proteins with D8C located in the extracellular part. We did homologue modeling and molecular dynamics to simulate the structure of D8C and its mutants. The second structures from DSSP accord with CD results. So this structure could be used to screen small compounds for myeloma kidney. Mutation of UMOD gene, which code uromodulin, is responsible for familial juvenile hyperuricaemic nephropathy (FJHN) and Medullary Cystic Kidney Disease type 2 (MCKD2). So far 38 mutants were identified and 11 of them located in D8C domain. D8C consists of fourα-helices and twoβ-sheets. Through analyzing the simulation trajectories, the most obvious change is that wild type D8C shows a sharp peak located in GWFRY (201-205aa) compared with mutants. The radius of gyration and solvent accessible area are bigger in wild type than in mutants. We predict that the mutant protein can not pass ER "quality control", maybe can not dissociate from chaperon protein and delay in ER for these structure changes. This is in agreement with fluorescence experiment that mutant protein is delayed in ER and little trafficks to Golgi compartment and plasma membrane, which have been reported. Also we infer that D8C is involved in protein-protein interaction, among which the conserved aromatic amino acids GWFRY may be important for the process.In the third part, we analyzed the expression of CypA and its membrane receptor CD147 in several kinds of lung cancer cells as well as normal lung cell and found that in H446 cell, a small cell lung cancer cell, the expressions of both CypA and CD147 are the highest. The exogeneous CypA protein can substantially stimulate H446 cell growth in dependence on its PPIase activity. We also showed that CypA protein can stimulate ERK1/2 signal in a dose and time dependent manner; but have no stimulation effect on p38 and JNK signals. We predict that exogeneous CypA may function through its receptor CD147. Elucidation of the precise role of CypA in these pathways may lead to new targeted therapies for small cell lung cancer.