31P nuclear magnetic resonance spectroscopy, histology and cytokinetics of a xenografted hypopharynx carcinoma following treatment with cisplatin: comparison in three sublines with increasing resistance

Abstract

Glickson, 1989). Some previous studies revealed that administration of chemotherapy was often accompanied by reenergisation of the tumours, whilst in the case of certain regimens of chemotherapy and, especially, of hyperthermia, contrary effects were observed (for an overview see Steen, 1989). The PMEs as precursors of cell membrane phospholipid synthesis generally showed a decline following chemotherapy (Lutz et al., 1988;Daly et al., 1990). However, to our knowledge, only Evelhoch and coworkers (1987) investigated whether these changes are response-specific markers indicating significant tumour regression following chemotherapy or whether they are related to an unspecific action of chemotherapy, occurring independently of drug cytotoxicity. They studied the in vivo response of a mammary adenocarcinoma sensitive to adriamycin in comparison to a drug-resistant subline following treatment with adriamycin by 31P NMR spectroscopy. As they could not find any changes in the phosphorus metabolism in the resistant subline following chemotherapy, the 31P NMR spectroscopic effects observed in the sensitive subline were assigned as response-specific markers for chemotherapy. Moreover, Cohen et al. (1986) reported differences in the levels of phospholipids and PCr in a MCF-7 mammary carcinoma cell line resistant to adriamycin in comparison to the sensitive wild type. This result was confirmed in Evelhoch's study (1987) , 1984;Toohill et al., 1987).In the present study we investigated the phosphorus metabolism, by 31P NMR spectroscopy, in a xenografted human epidermoid carcinoma of the hypopharynx, growing subcutaneously in athymic mice, and in two sublines of the tumour with an increasing resistance to CDDP. In contrast to the above mentioned studies, the sublines exhibited only partial resistance to CDDP, which is closer to the situation observed in human patient tumours. By comparing three tumour lines with continuously decreasing sensitivity to CDDP, we expected to be able to assign the phenomena related to drug resistance regarding the initial levels of the phosphorus containing metabolites in the tumours and the alterations induced by CDDP with regard to the therapeutic efficacy. Parallel to NMR spectroscopy, tumour cytokinetics and histology were investigated in order to relate the changes observed in the 31P NMR spectra with generally accepted indicators of tumour response. Materials and methodsTumour system and chemotherapy The investigations were performed on a moderately differentiated carcinoma of the hypopharynx which had been established from an untreated patient. The tumour was transplanted serially in male athymic mice (NMRI, nu/nu) and passaged by implanting tumour suspensions into the flank of the animals. From this tumour which was highly sensitive to cisplatin (CDDP), two sublines with an increasing degree of resistance to the drug were selected experimentally in vivo by repeated course treatment with CDDP over several generations. The subline with the lower resistance was maintained

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

“…The decrease in PC and increase in GPC/PC that we observed in association with reduced survival may be explained in part by increased membrane catabolism via phospholipase A 2 as observed by Ruiz-Cabello et al [63] and/or cell growth arrest. A decrease in PME has been frequently reported as an indicator for tumor response to therapy [19,43,64,65]. Our results are consistent with this observation, whereby the decrease in total PME is primarily due to the decrease in PC.…”

Value of 31 P NMR spectroscopy in predicting the response of a xenografted human hypopharynx carcinoma to irradiation

“…The spectral alterations observed in the present study are partly in contrast with the changes previously reported after therapy of the same xenograft with cisplatin (Tausch-Treml et al 1992a). While the PME/TPC and the PDE/TPC ratios as well as the pH value showed analogous changes in both studies, an increase of the high-energy phosphates phosphocreatine and b-NTP developed under the in¯uence of cisplatin.…”

“…The most signi®cant changes were increases of the PME/TPC and the PDE/TPC ratios (P < 0.01) detectable within 2 days. As described previously, the PME peak has been assigned to phosphocholine and phosphoethanolamine while the PDE peak consisted of glycerophosphocholine and glycerophosphoethanolamine (Tausch-Treml et al 1992a). In parallel, a moderate decrease of the PCr/TPC quotient (P < 0.05) appeared.…”

“…This phenomenon seemed to be based on an altered tumor blood supply. After chemotherapy, a remarkable dilatation of the capillaries was previously observed within the connective tissue of the hypopharynx carcinoma xenograft (Tausch-Treml et al 1992a). In the present study, no signi®cant eects of irradiation on the size of the blood vessels or on the energy status of tumors could be detected.…”

“…It was serially heterotransplanted in male athymic mice (NMRI, nu/nu) as described previously (Tausch-Treml et al 1991). Animals were kept in autoclaved cages set in laminar-air¯ow racks; food and acidi®ed water (pH 2.5) were provided ad libitum.…”