title: Therapeutic targeting the loss of the birt-hogg-dube suppressor gene.
abstract: Brit-Hogg-Dubé (BHD) syndrome, an autosomal dominant familial cancer, is associated with increased risk of kidney cancer. BHD syndrome is caused by loss-of-function mutations in the folliculin (FLCN) protein. To develop therapeutic approaches for renal cell carcinoma (RCC) in BHD syndrome, we adopted a strategy to identify tumor-selective growth inhibition in a RCC cell line with FLCN inactivation. The COMPARE algorithm was used to identify candidate anticancer drugs tested against the NCI-60 cell lines that showed preferential toxicity to low FLCN expressing cell lines. Fifteen compounds were selected and detailed growth inhibition (SRB) assays were done in paired BHD RCC cell lines (UOK257 derived from a patient with BHD). Selective sensitivity of FLCN-null over FLCN-wt UOK257 cells was observed in seven compounds. The most selective growth-inhibitory sensitivity was induced by mithramycin, which showed an approximately 10-fold difference in GI(50) values between FLCN-null (64.2 ± 7.9 nmol/L, n = 3) and FLCN-wt UOK257 cells (634.3 ± 147.9 nmol/L, n = 4). Differential ability to induce caspase 3/7 activity by mithramycin was also detected in a dose-dependent manner. Clonogenic survival studies showed mithramycin to be approximately 10-fold more cytotoxic to FLCN-null than FLCN-wt UOK257 cells (200 nmol/L). Following mithramycin exposure, UOK257-FLCN-null cells were mainly arrested and blocked in S and G(2)-M phases of the cell cycle and low dose of rapamycin (1 nmol/L) potentiated mithramycin sensitivity (1.5-fold in G(2)-M population and 2-fold in G(2)-M period time, 2xGI(50), 48 hours). These results provide a basis for further evaluation of mithramycin as a potential therapeutic drug for RCC associated with BHD.
authors.affiliation: Department of Medical and Molecular Genetics, School of Clinical and Experimental Medicine, University of Birmingham; Edgbaston, Birmingham B15 2TT, The United Kingdom.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Lu
authors.forename: Wenbin
authors.initials: W
authors.lastname: Wei
authors.forename: Janine
authors.initials: J
authors.lastname: Fenton
authors.forename: Michael S
authors.initials: MS
authors.lastname: Nahorski
authors.forename: Erzsebet
authors.initials: E
authors.lastname: Rabai
authors.forename: Anne
authors.initials: A
authors.lastname: Reiman
authors.forename: Laurence
authors.initials: L
authors.lastname: Seabra
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Nagy
authors.forename: Farida
authors.initials: F
authors.lastname: Latif
authors.forename: Eamonn R
authors.initials: ER
authors.lastname: Maher
mesh_terms: D000465:Algorithms; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D002292:Carcinoma, Renal Cell / Q000188:drug therapy* / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D016158:Genes, p53; D006801:Humans; D007680:Kidney Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D058990:Molecular Targeted Therapy; D051059:PTEN Phosphohydrolase / Q000235:genetics; D008926:Plicamycin / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics*; D020123:Sirolimus / Q000494:pharmacology; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D000970:Antineoplastic Agents; C476078:FLCN protein, human; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D053148:Caspase 3; D053179:Caspase 7; D008926:Plicamycin; D020123:Sirolimus