Ifosfamide metabolite chloroacetaldehyde inhibits cell proliferation and glucose metabolism without decreasing cellular ATP content in human breast cancer cells MCF-7

Dissecting Drug-Induced Cytotoxicity and Metabolic Dysfunction in Conditionally Immortalized Human Proximal Tubule Cells

Fourteen to 26 percent of all hospitalized cases of acute kidney injury are explained by drug-induced toxicity, emphasizing the importance of proper strategies to pre-clinically assess renal toxicity. The MTT assay is widely used as a measure of cell viability, but largely depends on cellular metabolic activity. Consequently, MTT as a single assay may not be the best way to assess cytotoxicity of compounds that reduce mitochondrial function and cellular metabolic activity without directly affecting cell viability. Accordingly, we aim to highlight the limitations of MTT alone in assessing renal toxicity of compounds that interfere with metabolic activity. Therefore, we compared toxic effects observed by MTT with a fluorescent assay that determines compromised plasma membrane permeability. Exposure of proximal tubule epithelial cells to nephrotoxic compounds reduced cellular metabolic activity concentration- and time-dependently. We show that compared to our fluorescence-based approach, assessment of cellular metabolic activity by means of MTT provides a composite readout of cell death and metabolic impairment. An approach independent of cellular metabolism is thus preferable when assessing cytotoxicity of compounds that induce metabolic dysfunction. Moreover, combining both assays during drug development enables a first discrimination between compounds having a direct or indirect mitochondrial toxic potential.

Ifosfamide nephrotoxicity in adult patients

Background

Ifosfamide, a widely prescribed antineoplasic agent, is frequently associated with kidney dysfunction. Its nephrotoxicity is well documented in children, but data are lacking in adult patients.

Methods

The aim of this retrospective study was to describe the clinical, biological and histological characteristics of ifosfamide nephrotoxicity.

Results

We report 34 patients (median age: 41 years) admitted in six French nephrology departments for kidney failure and/or tubular dysfunction. Fifteen patients (44.1%) received cisplatin as part of their chemotherapy. In 6 patients (17.7%), ifosfamide nephrotoxicity was revealed by a proximal tubular dysfunction (PTD), in 5 patients (14.4%) by an acute kidney injury (AKI), in 6 patients (17.7%) by a chronic kidney disease (CKD) and in 17 patients (49.7%) by an association of PTD and AKI. Fourteen renal biopsies (41.2%) were performed and revealed acute tubular necrosis (85.7%), vacuolation (78.6%) and nuclear atypias (71.4%) of renal epithelial cells, interstitial inflammation (71.4%) and fibrosis (57.1%). Electron microscopy showed mitochondrial enlargement and dysmorphic changes suggestive of mitochondrial toxicity. Ten patients (29.4%) progressed to Stage 5 CKD, six (17.6%) required haemodialysis and six patients died during a median follow-up period of 31 months. Risk factors for Stage 5 CKD were age and cisplatin co-administration.

Pyruvate Treatment Restores the Effectiveness of Chemotherapeutic Agents in Human Colon Adenocarcinoma and Pleural Mesothelioma Cells

Emerging evidence supports the idea that a dysfunction in cell metabolism could sustain a resistant phenotype in cancer cells. As the success of chemotherapeutic agents is often questioned by the occurrence of multidrug resistance (MDR), a multiple cross-resistance towards different anti-cancer drugs represent a major obstacle to cancer treatment. The present study has clarified the involvement of the carbon metabolites in a more aggressive tumor colon adenocarcinoma phenotype and in a chemoresistant mesothelioma, and the role of pyruvate treatment in the reversion of the potentially related resistance. For the first time, we have shown that human colon adenocarcinoma cells (HT29) and its chemoresistant counterpart (HT29-dx) displayed different carbon metabolism: HT29-dx cells had a higher glucose consumption compared to HT29 cells, whereas human malignant mesothelioma (HMM) cells showed a lower glucose consumption compared to HT29 cells, accompanied by a lower pyruvate production and, consequently, a higher production of lactate. When treated with pyruvate, both HT29-dx and HMM cells exhibited a re-established accumulation of doxorubicin and a lower survival ability, a decreased activity of multidrug resistance protein 1 (MRP1) and a restored mitochondrial respiratory chain function, improving the effectiveness of the chemotherapeutic agents in these resistant cancer cells.

[Ifosphamide nephrotoxicity]

Ifosfamide is a cytotoxic drug usually used in malignant sarcomas. The nephrotoxicity of this agent has been described essentially among children, revealed by renal failure and proximal tubulopathy. We recently conducted a retrospective multicentre study, describing 34 adult patients admitted for ifosfamide nephrotoxicity. More than 80% of them presented with renal failure, diagnosed up to 48 months after ifosfamide administration. A Fanconi syndrome with hypophosphoremia, hypokaliemia, glucosuria and low-molecular weight proteinuria, was present in two third of all cases. Median estimated glomerular filtration rate was 31mL/min 1 month and 38mL/min 3 months after ifosfamide infusion, versus 67mL/min at baseline. Renal biopsy, performed in 14 of these patients, showed acute tubular necrosis with vacuolization of proximal tubular epithelial cells with marked nuclear modifications, whereas electron microscopy revealed major changes of mitochondrial structure inside those cells, suggesting a tenofovir-like mechanism of nephrotoxicity. After a median follow-up of 31 months, ten patients out of 34 reached stage 5 chronic kidney disease, requiring dialysis in five cases. Poor renal prognosis was associated with concomitant cisplatin use (P=0.02) and with older age at presentation (P=0.04). In conclusion, ifosfamide nephrotoxicity is often severe and irreversible, leading to proximal tubulopathy and sometimes-severe chronic kidney failure, that can be immediate or delayed, sometimes diagnosed months after chemotherapy completion.

Automated platform for sensor-based monitoring and controlled assays of living cells and tissues

Cellular assays have become a fundamental technique in scientific research, pharmaceutical drug screening or toxicity testing. Therefore, the requirements of technical developments for automated assays raised in the same rate. A novel measuring platform was developed, which combines automated assay processing with label-free high-content measuring and real-time monitoring of multiple metabolic and morphologic parameters of living cells or tissues. Core of the system is a test plate with 24 cell culture wells, each equipped with opto-chemical sensor-spots for the determination of cellular oxygen consumption and extracellular acidification, next to electrode-structures for electrical impedance sensing. An automated microscope provides the optical sensor read-out and allows continuous cell imaging. Media and drugs are supplied by a pipetting robot system. Therefore, assay can run over several days without personnel interaction. To demonstrate the performance of the platform in physiologic assays, we continuously recorded the kinetics of metabolic and morphologic parameters of MCF-7 breast cancer cells under the influence of the cytotoxin chloroacetaldehyde. The data point out the time resolved effect kinetics over the complete treatment period. Thereby, the measuring platform overcomes problems of endpoint tests, which cannot monitor the kinetics of different parameters of the same cell population over longer time periods.