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

Abstract

KTCTL-26 and KTCTL-2 are renal cell carcinoma (RCC) lines with high and low expression of P-170 glycoprotein, respectively. Inherent differences between the two cell lines in terms of phosphate metabolites and growth characteristics in culture were examined for possible association with multidrug resistance (MDR). Differences in response to drug treatment were investigated for 40 h incubations with various doses of vinblastine (VBL) alone or as cotreatments with various concentrations of the calcium antagonist diltiazem (DIL) and/or interferon-alpha (IFN-alpha). Treatment effects were quantitated using the MTT survival assay and 31P magnetic resonance spectroscopy (MRS) to determine phosphate metabolite profiles in intact cells. KTCTL-2 and KTCTL-26 cells exhibited significant inherent differences in phosphocholine, glycerophosphocholine, glycerophosphoethanolamine, and phosphocreatine levels. KTCTL-26 cells were more sensitive than KTCTL-2 to 0.011 mircroM VBL alone (87% vs. 102% survival) or to 0.011 microM BL + 10 microM DIL (55% vs. 80% survival). The latter treatment resulted in a significant decrease in the ratio of phosphocholine to glycerophosphocholine in KTCTL-26 cells but no significant changes in phosphate metabolites in KTCTL-2 cells. Metabolomic 31P MRS detects different metabolite profiles for RCC cell lines with different MDR phenotypes and may be useful for noninvasive characterization of tumors in a clinical setting.

Expression of Cell-Surface Marker ABCB5 Causes Characteristic Modifications of Glucose, Amino Acid and Phospholipid Metabolism in the G3361 Melanoma-Initiating Cell Line

“…This was in agreement with previously reported 31 P NMR studies of various MDR1-transfected cancer cells [15]. By contrast, ATP, another high-energy metabolite, was lower in KTCTL-26 than in KTCTL-2, which was linked to KTCTL-2 drug resistance effects other than MDR [14]. Similarly, levels of phosphodiesters (PDE), which are known to be phospholipid degradation products, were decreased in KTCTL-26 vs .…”

“…Glycolysis is closely linked to energy metabolism. We have previously demonstrated, in a comparison between two renal cell carcinoma (RCC) cell lines, that the high-MDR1 cell line, KTCTL-26, had a higher energetic status and an increased level of the high-energy metabolite, phosphocreatine (PCr), when compared with the low-MDR1 cell line, KTCTL-2 [14]. This was in agreement with previously reported 31 P NMR studies of various MDR1-transfected cancer cells [15].…”

“…KTCTL-2 cells, although low PDE are generally associated with low MDR1 expression [15–17]. Again, this effect was ascribed to KTCTL-2 drug resistance effects other than MDR [14]. In summary, work previously carried out by us and others suggests that the presence of multiple, redundant mechanisms of resistance may be at the origin of confounding parameters when metabolic effects of ABC transporter-expressing cells are studied.…”

Real‐time measurement of hyperpolarized lactate production and efflux as a biomarker of tumor aggressiveness in an MR compatible 3D cell culture bioreactor

“…The intracellular inorganic phosphate (P i ) peak was resolved from the P i signal arising from the circulating medium for both the UOK262 and the UMRC6 cells. The intracellular pH values of these cells were calculated using the chemical shift of the P i peak, the known pH of the medium (7.67 ± 0.04 at 37 °C), and published methods . All bioreactor studies were conducted under the continuous perfusion condition of 0.5 mL/min ( n = 6), except for the flow modulation experiments when the pump was stopped 15 s after the completion of the HP substrate infusion ( n = 3).…”

Nmr Metabolomics of Renal Cancer: an Overview

“…To our knowledge, only one study has employed NMR of renal cancer cell lines [46], thus taking advantage of the easily controllable, albeit oversimplified in interpretation, biological setup of cell studies compared with tissues or biofluids analysis. That study considered two human ccRCC lines, KTCTL-26 and KTCTL-2, characterized by high and low expressions of P-170 glycoprotein (or MRD1 protein), respectively.…”