Metabolomic profiling of the synergistic effects of melittin in combination with cisplatin on ovarian cancer cells

Melittin, the main peptide present in bee venom, has been proposed as having potential for anticancer therapy; the addition of melittin to cisplatin, a first line treatment for ovarian cancer, may increase the therapeutic response in cancer treatment via synergy, resulting in improved tolerability, reduced relapse, and decreased drug resistance. Thus, this study was designed to compare the metabolomic effects of melittin in combination with cisplatin in cisplatin-sensitive (A2780) and resistant (A2780CR) ovarian cancer cells. Liquid chromatography (LC) coupled with mass spectrometry (MS) was applied to identify metabolic changes in A2780 (combination treatment 5 μg/mL melittin + 2 μg mL cisplatin) and A2780CR (combination treatment 2 μg/mL melittin + 10 μg/mL cisplatin) cells. Principal components analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) multivariate data analysis models were produced using SIMCA-P software. All models displayed good separation between experimental groups and high-quality goodness of fit (R2) and goodness of prediction (Q2), respectively. The combination treatment induced significant changes in both cell lines involving reduction in the levels of metabolites in the tricarboxylic acid (TCA) cycle, oxidative phosphorylation, purine and pyrimidine metabolism, and the arginine/proline pathway. The combination of melittin with cisplatin that targets these pathways had a synergistic effect. The melittin-cisplatin combination had a stronger effect on the A2780 cell line in comparison with the A2780CR cell line. The metabolic effects of melittin and cisplatin in combination were very different from those of each agent alone

Metabolomic profiling of the effects of melittin and cisplatin on ovarian cancer cells using high resolution mass spectrometry

Over the last few years, metabolomics has come to play an increasingly important part in many fields of research, notably medical studies. However, there is a dearth of research on metabolomics in the area of ovarian cancer and the increase in anti-cancer (platinum) drug resistance. Thus further studies on the modes of anticancer action and the mechanisms of resistance of ovarian cancer cells at the metabolome level are needed. The aim of this study was to characterise the metabolic profiles of two human ovarian cancer cell lines, A2780 (cisplatin-sensitive) and A2780CR (cisplatin-resistant), in response to their exposure to melittin, cisplatin and melittin-cisplatin combination therapy. It has been suggested that melittin may have potential as an anti-cancer therapy; combining cisplatin and melittin may increase response and tolerability in cancer treatment, as well as reducing drug resistance.The A2780 and A2780CR cell lines were treated with sub-lethal doses of melittin, cisplatin and melittin-cisplatin combination therapy for 24 hours before extraction and global metabolite analysis of cell lysates by LC-MS using a HPLC system. Phenotype MicroArray™ experiments were also applied in order to test carbon substrate utilisation or sensitivity in both cell lines after exposure to melittin and cisplatin. Data extraction was carried out with MZmine 2.10 with metabolite searching against an in-house database. The data were analysed using univariate and multivariate methods.The changes induced by melittin in the cisplatin-sensitive cells mainly resulted in reduced levels of amino acids in the proline/glutamine/arginine pathway, as well as to decreased levels of carnitines, polyamines, ATP and NAD+. It was necessary to evaluate the effect of a melittin on lipid activities of ovarian cancer cell lines. In order to do so, an LC coupled to an Orbitrap Exactive mass spectrometer using an ACE silica gel column was employed. The two cell lines had distinct lipid compositions, with the A2780CR cells having lower levels of several ether lipids than the A2780 cells. The changes induced by melittin in both cell lines mainly led to a decrease the level of PC and PE. Lipids were significantly altered in both A2780 and A2780CR cells. The observed effect was much more marked in the cisplatin-sensitive cells, suggesting that the sensitive cells undergo much more extensive membrane re-modelling in responsexviito melittin in comparison with the resistant cells. Regarding the metabolic effects of cisplatin on A2780 cells, these mainly resulted decreased levels of acetylcarnitine, phosphocreatine, arginine, proline and glutathione disulfide, as well as to increased levels of tryptophan and methionine. A number of metabolites were differently affected between the A2780 and A2780CR cells following cisplatin treatment, with A2780CR cells presenting increased levels of lysine, and decreased levels of N-acetyl-glutamate, oxoglutarate and 2-oxobutanoate compared to sensitive cells. However, when the combination treatment was applied, there were significant changes in both cell lines, mainly resulting in a reduction of levels of citrate cycle, oxidative phosphorylation, purine, pyrimidine and arginine/proline pathways. The combination of melittin with cisplatin has a synergistic effect when targeting these pathways. The melittin-cisplatin combination had stronger effect on A2780 cell lines than it had on those of A2780CR.Overall, this study suggests that melittin may have some potential as an adjuvant therapy in cancer treatment. A global metabolomics approach can be a useful tool for evaluating the pharmacological effects of anti-cancer compounds or synergetic sensitisers using mass spectrometry.Over the last few years, metabolomics has come to play an increasingly important part in many fields of research, notably medical studies. However, there is a dearth of research on metabolomics in the area of ovarian cancer and the increase in anti-cancer (platinum) drug resistance. Thus further studies on the modes of anticancer action and the mechanisms of resistance of ovarian cancer cells at the metabolome level are needed. The aim of this study was to characterise the metabolic profiles of two human ovarian cancer cell lines, A2780 (cisplatin-sensitive) and A2780CR (cisplatin-resistant), in response to their exposure to melittin, cisplatin and melittin-cisplatin combination therapy. It has been suggested that melittin may have potential as an anti-cancer therapy; combining cisplatin and melittin may increase response and tolerability in cancer treatment, as well as reducing drug resistance.The A2780 and A2780CR cell lines were treated with sub-lethal doses of melittin, cisplatin and melittin-cisplatin combination therapy for 24 hours before extraction and global metabolite analysis of cell lysates by LC-MS using a HPLC system. Phenotype MicroArray™ experiments were also applied in order to test carbon substrate utilisation or sensitivity in both cell lines after exposure to melittin and cisplatin. Data extraction was carried out with MZmine 2.10 with metabolite searching against an in-house database. The data were analysed using univariate and multivariate methods.The changes induced by melittin in the cisplatin-sensitive cells mainly resulted in reduced levels of amino acids in the proline/glutamine/arginine pathway, as well as to decreased levels of carnitines, polyamines, ATP and NAD+. It was necessary to evaluate the effect of a melittin on lipid activities of ovarian cancer cell lines. In order to do so, an LC coupled to an Orbitrap Exactive mass spectrometer using an ACE silica gel column was employed. The two cell lines had distinct lipid compositions, with the A2780CR cells having lower levels of several ether lipids than the A2780 cells. The changes induced by melittin in both cell lines mainly led to a decrease the level of PC and PE. Lipids were significantly altered in both A2780 and A2780CR cells. The observed effect was much more marked in the cisplatin-sensitive cells, suggesting that the sensitive cells undergo much more extensive membrane re-modelling in responsexviito melittin in comparison with the resistant cells. Regarding the metabolic effects of cisplatin on A2780 cells, these mainly resulted decreased levels of acetylcarnitine, phosphocreatine, arginine, proline and glutathione disulfide, as well as to increased levels of tryptophan and methionine. A number of metabolites were differently affected between the A2780 and A2780CR cells following cisplatin treatment, with A2780CR cells presenting increased levels of lysine, and decreased levels of N-acetyl-glutamate, oxoglutarate and 2-oxobutanoate compared to sensitive cells. However, when the combination treatment was applied, there were significant changes in both cell lines, mainly resulting in a reduction of levels of citrate cycle, oxidative phosphorylation, purine, pyrimidine and arginine/proline pathways. The combination of melittin with cisplatin has a synergistic effect when targeting these pathways. The melittin-cisplatin combination had stronger effect on A2780 cell lines than it had on those of A2780CR.Overall, this study suggests that melittin may have some potential as an adjuvant therapy in cancer treatment. A global metabolomics approach can be a useful tool for evaluating the pharmacological effects of anti-cancer compounds or synergetic sensitisers using mass spectrometry

Metabolomic Profiling of the Effects of Melittin on Cisplatin Resistant and Cisplatin Sensitive Ovarian Cancer Cells Using Mass Spectrometry and Biolog Microarray Technology

In the present study, liquid chromatography-mass spectrometry (LC-MS) was employed to characterise the metabolic profiles of two human ovarian cancer cell lines A2780 (cisplatin-sensitive) and A2780CR (cisplatin-resistant) in response to their exposure to melittin, a cytotoxic peptide from bee venom. In addition, the metabolomics data were supported by application of Biolog microarray technology to examine the utilisation of carbon sources by the two cell lines. Data extraction with MZmine 2.14 and database searching were applied to provide metabolite lists. Principal component analysis (PCA) gave clear separation between the cisplatin-sensitive and resistant strains and their respective controls. The cisplatin-resistant cells were slightly more sensitive to melittin than the sensitive cells with IC50 values of 4.5 and 6.8 μg/mL respectively, although the latter cell line exhibited the greatest metabolic perturbation upon treatment. The changes induced by melittin in the cisplatin-sensitive cells led mostly to reduced levels of amino acids in the proline/glutamine/arginine pathway, as well as to decreased levels of carnitines, polyamines, adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide (NAD+). The effects on energy metabolism were supported by the data from the Biolog assays. The lipid compositions of the two cell lines were quite different with the A2780 cells having higher levels of several ether lipids than the A2780CR cells. Melittin also had some effect on the lipid composition of the cells. Overall, this study suggests that melittin might have some potential as an adjuvant therapy in cancer treatment