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Silencing of human ferrochelatase causes abundant protoporphyrin-IX accumulation in colon cancer

Item Type:Article
Title:Silencing of human ferrochelatase causes abundant protoporphyrin-IX accumulation in colon cancer
Creators Name:Kemmner, W. and Wan, K. and Ruttinger, S. and Ebert, B. and Macdonald, R. and Klamm, U. and Moesta, K.T.
Abstract:Hemes and heme proteins are vital components of essentially every cell of virtually every eukaryote organism. Previously, we demonstrated accumulation of the heme precursor protoporphyrin-IX (PpIX) in gastrointestinal tumor tissues. To elucidate the mechanisms of PpIX accumulation by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we studied expression of the relevant enzymes of the heme synthetic pathway. Here, we describe a significant down-regulation of ferrochelatase (FECH) mRNA expression in gastric, colonic, and rectal carcinomas. Accordingly, in an in vitro model of several carcinoma cell lines, ferrochelatase down-regulation and loss of enzymatic activity corresponded with an enhanced PpIX-dependent fluorescence. Direct detection of PpIX in minute amounts was achieved by a specifically developed pulsed solid-state laser dual delay fluorimetry setup. Silencing of FECH using small interfering RNA (siRNA) technology led to a maximum 50-fold increased PpIX accumulation, imageable by a specifically adapted two-photon microscopy unit. Our results show that in malignant tissue a transcriptional down-regulation of FECH occurs, which causes endogenous PpIX accumulation. Furthermore, accumulation of intracellular PpIX because of FECH siRNA silencing provides a small-molecule-based approach to molecular imaging and molecular therapy—Kemmner, W., Wan, K., Ruettinger, S., Ebert, B., Macdonald, R., Klamm, U., Moesta, K. T. Silencing of human ferrochelatase causes abundant protoporphyrin-IX accumulation in colon cancer.
Keywords:Heme metabolism, Gastrointestinal carcinomas, siRNA silencing, Cytoplasmatic red fluorescence
Source:FASEB Journal
ISSN:0892-6638
Publisher:Federation of American Societies for Experimental Biology (U.S.A.)
Volume:22
Number:2
Page Range:500-509
Date:February 2008
Official Publication:https://doi.org/10.1096/fj.07-8888com
PubMed:View item in PubMed

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