Inhibition of 6-phosphofructo-2-kinase (PFKFB3) suppresses glucose metabolism and the growth of HER2+ breast cancer.
Human epidermal growth factor receptor-2 (HER2) has been implicated in the progression of multiple tumor types, including breast cancer, and many downstream effectors of HER2 signaling are primary regulators of cellular metabolism, including Ras and Akt. A key downstream metabolic target of Ras and Akt is the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 isozyme (PFKFB3), whose product, fructose-2,6-bisphosphate (F26BP), is a potent allosteric activator of a rate-limiting enzyme in glycolysis, 6-phosphofructo-1-kinase (PFK-1). We postulate that PFKFB3 may be regulated by HER2 and contribute to HER2-driven tumorigenicity.



Immunohistochemistry and Kaplan-Meier analysis of HER2+ patient samples investigated the relevance of PFKFB3 in HER2+ breast cancer. In vitro genetic and pharmacological inhibition of PFKFB3 was utilized to determine effects on HER2+ breast cancer cells, while HER2 antagonist treatment assessed the mechanistic regulation on PFKFB3 expression and glucose metabolism. Administration of a PFKFB3 inhibitor in a HER2-driven transgenic breast cancer model evaluated this potential therapeutic approach in vivo.



PFKFB3 is elevated in human HER2+ breast cancer and high PFKFB3 transcript correlated with poorer progression-free (PFS) and distant metastatic-free (DFMS) survival. Constitutive HER2 expression led to elevated PFKFB3 expression and increased glucose metabolism, while inhibition of PFKFB3 suppressed glucose uptake, F26BP, glycolysis, and selectively decreased the growth of HER2-expressing breast cancer cells. In addition, treatment with lapatinib, an FDA-approved HER2 inhibitor, decreased PFKFB3 expression and glucose metabolism in HER2+ cells. In vivo administration of a PFKFB3 antagonist significantly suppressed the growth of HER2-driven breast tumors and decreased18F-2-deoxy-glucose uptake.



Taken together, these data support the potential clinical utility of PFKFB3 inhibitors as chemotherapeutic agents against HER2+ breast cancer.
Department of Medicine, University of Louisville, Louisville, KY, 40202, USA.|Molecular Targets Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.|Department of Medicine, Washington University, Saint Louis, MO, 63110, USA.
Julie
J
O'Neal
Department of Medicine, University of Louisville, Louisville, KY, 40202, USA.|Molecular Targets Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.
Amy
A
Clem
Department of Biochemistry and Molecular Genetics, University of Louisville, 505 South Hancock Street, CTRB, Rm. 422, Louisville, KY, 40202, USA.|Molecular Targets Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.
Lindsey
L
Reynolds
Department of Biochemistry and Molecular Genetics, University of Louisville, 505 South Hancock Street, CTRB, Rm. 422, Louisville, KY, 40202, USA.|Molecular Targets Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.
Susan
S
Dougherty
Department of Medicine, University of Louisville, Louisville, KY, 40202, USA.|Molecular Targets Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.
Yoannis
Y
Imbert-Fernandez
Department of Medicine, University of Louisville, Louisville, KY, 40202, USA.|Molecular Targets Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.
Sucheta
S
Telang
Department of Medicine, University of Louisville, Louisville, KY, 40202, USA.|Molecular Targets Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.
Jason
J
Chesney
Department of Biochemistry and Molecular Genetics, University of Louisville, 505 South Hancock Street, CTRB, Rm. 422, Louisville, KY, 40202, USA. bfclem01@louisville.edu.|Molecular Targets Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA. bfclem01@louisville.edu.
Brian F
BF
Clem
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D015870:Gene Expression; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D051379:Mice; D008822:Mice, Transgenic; D025481:Phosphofructokinase-2 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D047368:Tumor Burden
D000970:Antineoplastic Agents; D005947:Glucose; D025481:Phosphofructokinase-2; D012333:RNA, Messenger; D018719:Erb-b2 Receptor Tyrosine Kinases; C107345:PFKFB3 protein, human; C508053:ERBB2 protein, human
6-Phosphofructo-2-kinase; Breast cancer; Chemotherapy; Fructose-2,6-Bisphosphate; Glycolysis; HER2