Inhibition of glucose turnover by 3-bromopyruvate counteracts pancreatic cancer stem cell features and sensitizes cells to gemcitabine

Abstract

According to the cancer stem cell (CSC) hypothesis, the aggressive growth and early metastasis of pancreatic ductal adenocarcinoma (PDA) is due to the activity of CSCs, which are not targeted by current therapies. Otto Warburg suggested that the growth of cancer cells is driven by a high glucose metabolism. Here, we investigated whether glycolysis inhibition targets CSCs and thus may enhance therapeutic efficacy. Four established and 3 primary PDA cell lines, non-malignant cells, and 3 patient-tumor-derived CSC-enriched spheroidal cultures were analyzed by glucose turnover measurements, MTT and ATP assays, flow cytometry of ALDH1 activity and annexin positivity, colony and spheroid formation, western blotting, electrophoretic mobility shift assay, xenotransplantation, and immunohistochemistry. The effect of siRNA-mediated inhibition of LDH-A and LDH-B was also investigated. The PDA cells exhibited a high glucose metabolism, and glucose withdrawal or LDH inhibition by siRNA prevented growth and colony formation. Treatment with the anti-glycolytic agent 3-bromopyruvate almost completely blocked cell viability, self-renewal potential, NF-κB binding activity, and stem cell-related signaling and reverted gemcitabine resistance. 3-bromopyruvate was less effective in weakly malignant PDA cells and did not affect non-malignant cells, predicting minimal side effects. 3-bromopyruvate inhibited in vivo tumor engraftment and growth on chicken eggs and mice and enhanced the efficacy of gemcitabine by influencing the expression of markers of proliferation, apoptosis, self-renewal, and metastasis. Most importantly, primary CSC-enriched spheroidal cultures were eliminated by 3-bromopyruvate. These findings propose that CSCs may be specifically dependent on a high glucose turnover and suggest 3-bromopyruvate for therapeutic intervention.

Targeting the facilitative glucose transporter GLUT1 inhibits the self-renewal and tumor-initiating capacity of cancer stem cells

“…However, the role and significance of this propensity of CSCs toward highly glycolytic metabolism remain largely unknown. Recent studies have shown that 3-bromopyruvate, a hexokinase 2 (HK2) inhibitor, and its derivatives (pentyl 3-bromopyruvate ester [P-BrPE] and 3-bromo-2-oxopropionate-1-propyl ester [3-BrOP]) reduce the viability of CSCs and that knockdown of GLUT3 inhibits the growth of brain tumor CSCs [23, 25-28]. While all these studies do indicate that the glycolytic metabolism plays an essential role in the survival and proliferation of CSCs, it still remains to be shown whether the glycolytic metabolism has a role in the maintenance of the self-renewal capacity of CSCs.…”

New insights into pancreatic cancer stem cells

“…Another hedgehog antagonist Vismodegib (GDC-0449), inhibits pancreatic CSC characteristics in vitro [81] . Using GDC-0449, a human phase I clinical trial is ongoing [82] , which preliminarily suggest that GDC-0449 has good safety profile and antitumor activity for some of the locally advanced or metastatic solid tumors. Pancreatic cancer progression was inhibited by sulforaphane, green tea catechins and quercetin by inducing let7a miRNA and inhibiting Kras and ALDH1 activity [82] .…”

“…Using GDC-0449, a human phase I clinical trial is ongoing [82] , which preliminarily suggest that GDC-0449 has good safety profile and antitumor activity for some of the locally advanced or metastatic solid tumors. Pancreatic cancer progression was inhibited by sulforaphane, green tea catechins and quercetin by inducing let7a miRNA and inhibiting Kras and ALDH1 activity [82] . The 3-Bromopyruvate, a glycolysis inhibitor blocked CSC signaling in PC cell lines and the spheroids derived from patients [83] .…”

Catalpol promotes cellular apoptosis in human HCT116 colorectal cancer cells via microRNA-200 and the downregulation of PI3K-Akt signaling pathway

“…In addition, protein phosphatase activity is associated with tumors. Fish oil suppressed cell growth of colorectal cancer by regulating PTEN and nuclear factor-κB signaling (9 (12) reported that ribonuclease inhibitor suppresses proliferation and metastasis in colorectal cancer cells by inhibiting the PI3K/Akt signaling pathway. Catalpol is one of the primary active ingredients in rehmannia, which functions as a diuretic and laxative, and exhibits blood sugar-lowering, liver protective, anti-aging and anticancer effects (13)(14)(15)(16).…”