Comparison of action of the anti-neoplastic drug lonidamine on drug-sensitive and drug-resistant human breast cancer cells:31 P and 13C nuclear magnetic resonance studies

Abstract

Lonidamine (LND) is a relatively new anti-cancer drug, and several clinical trials have indicated that it may be effective in combinations with other therapeutic modalities. LND is classified within the metabolic inhibitor agents. Multidrug resistance (MDR) phenomenon is often associated with increased energy requirements, and enhanced glycolysis rate. These studies were performed to delineate the mechanism of action of LND on MDR human breast cancer cells, and to investigate whether LND as a single agent, or in combination with another anti-metabolism drug, 2-deoxyglucose (2-DG), may be useful against MDR tumors. The effects of LND on intact perfused drug-sensitive (WT) and 33-fold resistant to Adriamycin (Adr) MCF-7 cells, embedded in alginate micro capsules, were continuously monitored by 31P and 13C nuclear magnetic resonance (NMR) spectroscopy. 31P NMR studies showed that LND induced intracellular acidification and depletion of NTP in both WT and Adr cells. However, pH and NTP levels decreased less in the Adr cells than in the WT cells (p < 0.05 for both parameters). 13C NMR demonstrated that LND inhibited lactate transport, and lactate signals were elevated in both cell lines. However, the intracellular lactate levels increased to a greater extent in the WT than in the Adr cells (p < 0.05). There were major differences in the effects of LND on metabolism between sensitive and resistant cells. While LND enhanced glucose uptake in the WT cells, and its administration was followed by continuous increase of lactate signal, both processes were not affected by LND in the Adr cells. 2-DG is a glucose analogue that inhibits both cellular uptake and utilization of glucose, leading to cell starvation. Combined treatment with LND and 2-DG yielded at best additive, but not synergistic, cellular toxicity, and the metabolic effects of LND were attenuated by 2-DG. These results showed that the principal mechanism of action of LND is inhibition of lactate transport leading to intracellular lactate accumulation and acidification in both WT and Adr cells. The Adr cells were only 2-fold resistant to LND (compared to the WT cells), and since cellular uptake of alkaloid chemotherapy is improved in acidic environment, LND may have a role in the treatment protocols of MDR tumors, especially when given as the initial means for induction of intracellular acidification.

Detection of intracellular lactate with localized diffusion {1H–13C}-spectroscopy in rat glioma in vivo

“…The infusate, e.g., 13 C-labeled glucose (Glc), is detected together with its metabolic products. In healthy brain metabolism, label of [ 13 C] Glc is incorporated into glutamate (Glu) and glutamine (Gln) via the TCA cycle; in a tumor, non-oxidative glucose consumption leads to 13 Clabeled Lac and alanine (Ala) [20][21][22][23][24][25][26].…”

Investigation of multidrug resistance in cultured human renal cell carcinoma cells by 31P-NMR spectroscopy and treatment survival assays

“…31 P-MRS has been used to demonstrate that transfection of various cancer cell lines with the mdr1 gene, encoding for P-170 (MDR1), results in altered levels of phosphomonoesters (PME) and phosphodiesters (PDE) and an increase in phosphocreatine (PCr) and ATP levels in comparison with wild-type cells [20]. Over the past decade 31 P-, 1 H-and 13 C-MRS studies of a variety of cancer cell lines have revealed further differences in energy and lipid metabolism when comparing drugsensitive parental cells with variants rendered multidrugresistant by selection for drug tolerance [20][21][22][23][24][25][26]. Little is known, however, about the functional significance of the We present here a study of two human RCC lines, established in the Tumor Bank of the German Cancer Research Center, which differ with regard to growth characteristics, degree of differentiation, expression of P-170, and sensitivity to vinblastine (VBL).…”

MRI and MRS of intact perfused cancer cell metabolism, invasion, and stromal cell interactions

“…Treatment of human prostate cancer cells with two differentiating agents, phenylacetate and phenylbutyrate, resulted in an increase of MR detectable lipids and GPC . Perfused cell systems have been used to understand the effects of lonidamine in adriamycin resistant and wild type MCF‐7 cells, tumor necrosis factor‐α treatment of human breast cancer cells, radiation treatment, and cyclophosphamide treatment . Dichloroacetate (DCA), a pyruvate dehydrogenase kinase inhibitor, was used to treat poorly metastatic LNCaP and highly metastatic LNCaP‐LN3 prostate cancer cells.…”