Relationships between LDH-A, lactate, and metastases in 4T1 breast tumors.

Abstract

PURPOSE:

To investigate the relationship between lactate dehydrogenase A (LDH-A) expression, lactate concentration, cell metabolism, and metastases in murine 4T1 breast tumors.

EXPERIMENTAL DESIGN:

Inhibition of LDH-A expression and protein levels were achieved in a metastatic breast cancer cell line (4T1) using short hairpin RNA (shRNA) technology. The relationship between tumor LDH-A protein levels and lactate concentration (measured by magnetic resonance spectroscopic imaging, MRSI) and metastases was assessed.

RESULTS:

LDH-A knockdown cells (KD9) showed a significant reduction in LDH-A protein and LDH activity, less acid production, decreased transwell migration and invasion, lower proliferation, reduced glucose consumption and glycolysis, and increase in oxygen consumption, reactive oxygen species (ROS), and cellular ATP levels, compared with control (NC) cells cultured in 25 mmol/L glucose. In vivo studies showed lower lactate levels in KD9, KD5, and KD317 tumors than in NC or 4T1 wild-type tumors (P < 0.01), and a linear relationship between tumor LDH-A protein expression and lactate concentration. Metastases were delayed and primary tumor growth rate decreased.

CONCLUSIONS:

We show for the first time that LDH-A knockdown inhibited the formation of metastases, and was accompanied by in vivo changes in tumor cell metabolism. Lactate MRSI can be used as a surrogate to monitor targeted inhibition of LDH-A in a preclinical setting and provides a noninvasive imaging strategy to monitor LDH-A-targeted therapy. This imaging strategy can be translated to the clinic to identify and monitor patients who are at high risk of developing metastatic disease.

• Authors: Asif Rizwan, Inna Serganova, Raya Khanin, Hazem Karabeber, Xiaohui Ni, Sunitha Thakur, Kristen L Zakian, Ronald Blasberg, Jason A Koutcher
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 19 Issue 18 Pg. 5158-69 (Sep 15 2013) ISSN: 1557-3265 [Electronic] United States
• PMID: 23833310 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: ©2013 AACR.

Chemical References

• Isoenzymes
• RNA, Small Interfering
• Reactive Oxygen Species
• Lactic Acid
• Adenosine Triphosphate
• L-Lactate Dehydrogenase
• Lactate Dehydrogenase 5
• Glucose

Topics

• Adenosine Triphosphate (metabolism)
• Animals
• Breast Neoplasms (metabolism, pathology)
• Cell Adhesion
• Cell Movement
• Cell Proliferation
• Female
• Glucose (metabolism)
• Glycolysis
• Humans
• Isoenzymes (antagonists & inhibitors, genetics, metabolism)
• L-Lactate Dehydrogenase (antagonists & inhibitors, genetics, metabolism)
• Lactate Dehydrogenase 5
• Lactic Acid (metabolism)
• Lung Neoplasms (metabolism, secondary)
• Mice
• Oxygen Consumption
• RNA, Small Interfering (genetics)
• Reactive Oxygen Species
• Tumor Cells, Cultured