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Effects of incubation with liposomes at different temperatures on cultured melanoma cells (M14)
G Arancia1, A Calcabrini, P Matarrese
1Department of Ultrastructures, Istituto Superiore di Sanità, Rome, Italy.
Abstract:
A melanoma cell line (M14) was used in order to investigate the effect of hyperthermia on the mechanisms of interaction between liposomes and cultured cells. The treatment was performed by adding different concentrations of multilamellar liposomes (L-alpha-dipalmitoylphosphatidylcholine, stearylamine and cholesterol in the ratio 7:2:1) to cell cultures which were then incubated at 37.0 or 41.5 degrees C for 2 h. The damage induced by liposome treatment in normothermia or hyperthermia was evaluated by determining cell survival and by electron microscopy. When different concentrations of liposomes were used, a dose-dependent impairment of cell survival was observed. An enhancement of the cytotoxic effect was observed when the treatment was performed at 41.5 degrees C. This effect went on even after 24 h from the end of the treatment, but the difference between cells treated in normothermia and hyperthermia was remarkably reduced. The mechanism of the liposome-plasma membrane interaction has been investigated by electron microscopy. Our observations demonstrated that the outer bilayer of the multilamellar liposomes was capable of fusing with the plasma membrane, inducing changes in its fluidity and molecular organization. Following this process the inner liposomal bilayers entered the cell. These effects seemed to be favoured when the treatment was performed under mild hyperthermic conditions, accounting for the synergic cytotoxic action displayed by the liposome-hyperthermia association.
Insights
Hyperthermia enhances the cytotoxic effects of liposomes on melanoma cells by promoting membrane fusion and cellular uptake. This liposome-hyperthermia combination shows a synergistic effect on cell death.
Area of Science:
- Biophysics
- Cell Biology
- Nanotechnology
Background:
- Liposomes are widely investigated for drug delivery applications.
- Hyperthermia is a therapeutic approach that involves elevating body temperature.
- Understanding liposome-cell interactions is crucial for optimizing therapeutic strategies.
Purpose of the Study:
- To investigate the effect of hyperthermia on liposome-melanoma cell interactions.
- To elucidate the mechanisms underlying the enhanced cytotoxicity of liposomes under hyperthermia.
- To evaluate the impact of liposome concentration and temperature on cell survival.
Main Methods:
- Utilized a human melanoma cell line (M14).
- Treated cells with multilamellar liposomes (DPPC:stearylamine:cholesterol 7:2:1) at normothermic (37.0°C) and hyperthermic (41.5°C) conditions for 2 hours.
- Assessed cell damage via cell survival assays and electron microscopy.
Main Results:
- Observed a dose-dependent decrease in cell survival with increasing liposome concentrations.
- Hyperthermia (41.5°C) significantly enhanced the cytotoxic effect of liposomes.
- Electron microscopy revealed liposome-plasma membrane fusion and subsequent entry of inner liposomal bilayers into cells, a process favored by hyperthermia.
Conclusions:
- Mild hyperthermia synergistically enhances the cytotoxic action of liposomes on melanoma cells.
- The enhanced effect is attributed to increased liposome-plasma membrane fusion and cellular uptake under hyperthermic conditions.
- Liposome-hyperthermia association represents a promising strategy for melanoma treatment.