title: Proteasome inhibitor MG-132 modifies coxsackie and adenovirus receptor expression in colon cancer cell line lovo.
abstract: The efficacy of adenovirus vector-based cancer gene therapy is controversial. Its uptake by cells in many cases requires the major receptor for adenoviruses, the coxsackievirus and adenovirus receptor (CAR). Low transduction is believed to be one of the main barriers as the expression of CAR on tumor cells is frequently reduced. Increasing CAR expression on tumor cells thus offers a promising opportunity for more effective adenovirus based treatment. Expression of CAR in 62 cases of colon tumor specimens were examined with immunohistochemistry. To modify the CAR expression, the effects of proteasome inhibitor MG132 on CAR expression of colon cancer cell lines were determined by flow cytometry, RT-PCR, and western blot. To evaluate adenovirus transfer, we further used rAd.EGFP, rAd.p53, and oncolytic adenovirus to infect target cells. The CAR expression was significantly decreased in colon carcinomas, both in primary tumors and lymphonode metastasis. Though the deregulation of CAR occurred in early disease and showed no relationship with TNM stage, when primary tumors are more than 5 cm in diameter, this deregulation becomes more frequent. More importantly, proteasome inhibitor MG-132 could enhance CAR expression in colon carcinoma cell line lovo, accompanied with enhanced adenovirus transfer, target gene expression, and oncolysis. These data provide a rational basis for evaluation of CAR expression in tumors and pretreatment with CAR conditioner prior to adenovirus vector-based gene therapy.
authors.affiliation: State Key Laboratory of Oncology in South China, Biotherapy Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Nian-Hua
authors.initials: NH
authors.lastname: Zhang
authors.forename: Li-Bing
authors.initials: LB
authors.lastname: Song
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Wu
authors.forename: Rui-Ping
authors.initials: RP
authors.lastname: Li
authors.forename: Mu-Sheng
authors.initials: MS
authors.lastname: Zeng
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Zhu
authors.forename: De-Sen
authors.initials: DS
authors.lastname: Wan
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Zeng
authors.forename: Xiao-Shi
authors.initials: XS
authors.lastname: Zhang
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000188:drug therapy*; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry; D007976:Leupeptins / Q000494:pharmacology*; D011991:Receptors, Virus / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C568771:CLMP protein, human; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D011991:Receptors, Virus; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde