Hyperthermia enhances cytotoxicity of amine oxidase and spermine on drug-resistant LoVo colon adenocarcinoma cells

Abstract

Abstract. Hyperthermia is currently receiving widespread attention when associated with other therapeutic modalities, such as irradiation or chemotherapy, in the treatment of cancer. The occurrence of resistance to cytotoxic pharmacological agents in tumor cells, associated with several phenotypic alterations, is one of the major obstacles to successful anticancer chemotherapy. We investigated a new strategy to overcome multidrug resistance (MDR) cancer cells, using bovine serum amine oxidase (BSAO), which forms toxic products from spermine (H 2 O 2 and aldehydes). The cytotoxicity of the products was evaluated in drug-sensitive (LoVo WT) and multidrug-resistant (LoVo DX) colon adenocarcinoma cells at 37 and 42˚C, using a clonogenic cell survival assay. Cytotoxicity was considerably enhanced at 42˚C. Both toxic species contributed to the thermal enhancement of cytotoxicity induced by BSAO and spermine. Cytotoxicity was eliminated in the presence of catalase and aldehyde dehydrogenase (ALDH). An interesting finding was that BSAO and spermine at <1 μM, which were non toxic at 37˚C, became cytotoxic at 42˚C and resemble thermosensitizers. Cell survival results and electron microscopy investigations suggest that, at 42˚C, LoVo DX cells are not resistant to the cytotoxic enzymatic oxidation products of spermine, as was already demonstrated in these cells at 37˚C. Moreover, microscopy modifications caused by both toxic products were more pronounced in LoVo DX than in LoVo WT cells, where morphological cytoplasmatic alterations were shown. Our findings suggest that hyperthermia combined with the enzymatic toxic oxidation products of spermine might be a promising anticancer strategy, mainly against MDR tumor cells.

Cytotoxicity of spermine oxidation products to multidrug resistant melanoma M14 ADR2 cells: Sensitization by the MDL 72527 lysosomotropic compound

“…The prevention of cytotoxicity of spermine metabolites by catalase and ALDH confirmed previous results obtained among others, with human LoVo cells (15) or B16-F0 tumor cells (25), and showed that in the initial phase of spermine oxidation mainly hydrogen peroxide is effective as cytocidal agent, whereas the aldehydes formed from spermine are active only after their accumulation at a later stage of enzymatic reaction (incubation time >30 min). These effects were observed at both 37 and 42˚C, although cytotoxicity is higher at the elevated incubation temperature (15,43).…”

“…These effects were observed at both 37 and 42˚C, although cytotoxicity is higher at the elevated incubation temperature (15,43). In view of the sensitivity of human cancer cell lines to hydrogen peroxide, and in order to allow observing intermediary stages of cell damage, an experimental protocol was chosen that produces a slow release of metabolites over a limited period of time.…”

“…Moreover, it has previously been demonstrated that hydrogen peroxide and aldehydes generated by BSAO/ spermine enzymatic system were also able to overcome multidrug resistance (MDR) in human colon adenocarcinoma (LoVo) (15), and melanoma (M14) cells (11). Interestingly, both MDR cell types are more sensitive to cytotoxic spermine metabolites than their wild-type counterparts, an aspect of particular interest, since one of the problems of conventional anti-cancer therapy is the development of drug resistance.…”

Cellular Localization, Invasion, and Turnover Are Differently Influenced by Healthy and Tumor-Derived Extracellular Matrix

“…These findings are consistent with previous reports showing LoVo cells expressing PAS + mucus and microvilli in 2D system 32,33 and xenograft models, 34 and we provide evidence that healthy, perilesional, and tumor-derived ECM did not influence differentiation of LoVo cells.…”

Catalytically active bovine serum amine oxidase bound to fluorescent and magnetically drivable nanoparticles

“…22 Analogous to other radical forming processes, the formation of reactive oxygen species (ROS) and cytotoxic aldehydes from polyamines are currently being explored as a possible strategy in cancer therapy. 23 M oreover, h ydrogen peroxide and aldehydes generated by BSAO/spermine enzymatic systems have been shown to overcome multidrug resistance (MDR) in human colon adenocarcinoma (LoVo) 24,25 and melanoma (M14) cells. 26 This is particularly interesting because one of the problems of conventional anticancer therapy is the development of drug resistance.…”