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World J Gastroenterol. Oct 14, 2014; 20(38): 13705-13717
Published online Oct 14, 2014. doi: 10.3748/wjg.v20.i38.13705
Mechanisms of regulation of PFKFB expression in pancreatic and gastric cancer cells
Oleksandr H Minchenko, Katsuya Tsuchihara, Dmytro O Minchenko, Andreas Bikfalvi, Hiroyasu Esumi
Oleksandr H Minchenko, Dmytro O Minchenko, Department of Molecular Biology, Palladin Institute of Biochemistry, Kiev 01601, Ukraine
Katsuya Tsuchihara, Hiroyasu Esumi, Department of Innovative Oncology, National Cancer Center, Kashiwa, Chiba 277-8577, Japan
Dmytro O Minchenko, Department of Pediatrics, Bogomolets National Medical University, Kiev 01601, Ukraine
Andreas Bikfalvi, INSERM U1029 Molecular Angiogenesis and Cancer Microenvironment Laboratory, University Bordeaux I, 33405 Talence, France
Author contributions: Minchenko DO and Minchenko OH contributed equally to this work; Minchenko OH and Esumi H contributed to conception and design; Minchenko OH and Minchenko DO wrote the paper; Esumi H, Tsuchihara K, Minchenko OH and Bikfalvi A revised the article critically for important intellectual content and final approval of the version to be published.
Correspondence to: Oleksandr H Minchenko, PhD, Professor, Head, Department of Molecular Biology, Palladin Institute of Biochemistry, 9 Leontovicha St., Kiev 01601, Ukraine. ominchenko@yahoo.com
Telephone: +38-44-2356151 Fax: +38-44-2796365
Received: February 22, 2014
Revised: March 22, 2014
Accepted: May 19, 2014
Published online: October 14, 2014
Processing time: 235 Days and 23.1 Hours
Abstract

Enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 and -4 (PFKFB-3 and PFKFB-4) play a significant role in the regulation of glycolysis in cancer cells as well as its proliferation and survival. The expression of these mRNAs is increased in malignant tumors and strongly induced in different cancer cell lines by hypoxia inducible factor (HIF) through active HIF binding sites in promoter region of PFKFB-4 and PFKFB-3 genes. Moreover, the expression and hypoxia responsibility of PFKFB-4 and PFKFB-3 was also shown for pancreatic (Panc1, PSN-1, and MIA PaCa-2) as well as gastric (MKN45 and NUGC3) cancer cells. At the same time, their basal expression level and hypoxia responsiveness vary in the different cells studied: the highest level of PFKFB-4 protein expression was found in NUGC3 gastric cancer cell line and lowest in Panc1 cells, with a stronger response to hypoxia in the pancreatic cancer cell line. Overexpression of different PFKFB in pancreatic and gastric cancer cells under hypoxic condition is correlated with enhanced expression of vascular endothelial growth factor (VEGF) and Glut1 mRNA as well as with increased level of HIF-1α protein. Increased expression of different PFKFB genes was also demonstrated in gastric, lung, breast, and colon cancers as compared to corresponding non-malignant tissue counterparts from the same patients, being more robust in the breast and lung tumors. Moreover, induction of PFKFB-4 mRNA expression in the breast and lung cancers is stronger than PFKFB-3 mRNA. The levels of both PFKFB-4 and PFKFB-3 proteins in non-malignant gastric and colon tissues were more pronounced than in the non-malignant breast and lung tissues. It is interesting to note that Panc1 and PSN-1 cells transfected with dominant/negative PFKFB-3 (dnPFKFB-3) showed a lower level of endogenous PFKFB-3, PFKFB-4, and VEGF mRNA expressions as well as a decreased proliferation rate of these cells. Moreover, a similar effect had dnPFKFB-4. In conclusion, there is strong evidence that PFKFB-4 and PFKFB-3 isoenzymes are induced under hypoxia in pancreatic and other cancer cell lines, are overexpressed in gastric, colon, lung, and breast malignant tumors and undergo changes in their metabolism that contribute to the proliferation and survival of cancer cells. Thus, targeting these PFKFB may therefore present new therapeutic opportunities.

Keywords: 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3; 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-4; Hypoxia; Hypoxia inducible factor; Panc1; PST-1; MKN45; NUGC3; Gastric cancer; Lung cancer

Core tip: Enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 and -4 (PFKFB-3 and PFKFB-4) play a significant role in the regulation of glycolysis and cancer growth by inducing cell proliferation and surviving. The expression of these PFKFB is increased in malignant tumors and strongly induced in various cancer cell lines under hypoxia, including pancreatic and gastric cells. The high expression level of PFKFB-4 protein was found in NUGC3 gastric adenocarcinoma cells and much lower in pancreatic Panc1 cells, with the highest response to hypoxia in the pancreatic cancer cells. Both PFKFB-4 and PFKFB-3 are overexpressed in gastric, colon, lung, and breast cancers being more pronounced for PFKFB-4. Blocking both PFKFB-4 and PFKFB-3 may present new therapeutic opportunities.