Glucose metabolism of malignant cells is not regulated by transketolase-like (TKTL)-1.
An isoenzyme of transketolase, transketolase-like (TKTL)-1, has been hypothesized to play a pivotal role in the pathophysiology of malignant tumors. Available data are based on the detection of the putative TKTL-1 protein with one particular mouse monoclonal anti-TKTL-1 antibody, clone JFC12T10. In this study it was demonstrated that a) JFC12T10 detects multiple unspecific bands in Western blots, b) a 75-kDa band hitherto referred to as TKTL-1 corresponds to a nuclear protein and c) immunohistochemical detection of TKTL-1 in benign leiomyomas yields an expression pattern identical to that found in a variety of malignant tumors. In RT-PCR assays, using three different primer pairs for transketolase, TKTL-1 and yet another isogene of transketolase, TKTL-2, a relevant expression of TKTL-1 was not detectable in any of the 6 malignant tumor cell lines investigated (MCF-7, A549, HeLa, HT1080, M21 and TF-1). Expression levels of TKTL-1 were rather similar to those found for TKTL-2, although the latter has never been implicated in malignant disease. On the basis of these data, nutritional recommendations based on a hypothetically TKTL-1 controlled metabolism of tumor cells must be regarded as lacking scientific evidence.
Mayer
Arnulf
A
Department of Radiooncology and Radiotherapy, University Medical Center, Johannes Gutenberg University, 55131 Mainz, Germany. arnmayer@uni-mainz.de
Von Wallbrunn
Angelika
A
Vaupel
Peter
P
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism / Q000494:pharmacology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D005947:Glucose / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007889:Leiomyoma / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism*; D014174:Transketolase / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014594:Uterine Neoplasms / Q000235:genetics / Q000378:metabolism
D000911:Antibodies, Monoclonal; C505431:TKTL1 protein, human; D014174:Transketolase; D005947:Glucose