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Giant Lysosomes as a Chemotherapy Resistance Mechanism in Hepatocellular Carcinoma Cells.

Colombo F, Trombetta E, Cetrangolo P, Maggioni M, Razini P, De Santis F, Torrente Y, Prati D, Torresani E, Porretti L - PLoS ONE (2014)

Bottom Line: ABC expression analyses showed that the main ABC protein harboured by all of the cell lines was PGP, whose expression was not limited to the cell membrane but was also found on lysosomes.The findings of this study demonstrate the involvement of PGP-positive lysosomes in drug sequestration and MDR in HCC cell lines.The possibility of modulating this mechanism using PGP inhibitors could lead to the development of new targeted strategies to enhance HCC treatment.

View Article: PubMed Central - PubMed

Affiliation: Clinical Chemistry and Microbiology Laboratory, Flow Cytometry and Experimental Hepatology Service, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.

ABSTRACT
Despite continuous improvements in therapeutic protocols, cancer-related mortality is still one of the main problems facing public health. The main cause of treatment failure is multi-drug resistance (MDR: simultaneous insensitivity to different anti-cancer agents), the underlying molecular and biological mechanisms of which include the activity of ATP binding cassette (ABC) proteins and drug compartmentalisation in cell organelles. We investigated the expression of the main ABC proteins and the role of cytoplasmic vacuoles in the MDR of six hepatocellular carcinoma (HCC) cell lines, and confirmed the accumulation of the yellow anti-cancer drug sunitinib in giant (four lines) and small cytoplasmic vacuoles of lysosomal origin (two lines). ABC expression analyses showed that the main ABC protein harboured by all of the cell lines was PGP, whose expression was not limited to the cell membrane but was also found on lysosomes. MTT assays showed that the cell lines with giant lysosomes were more resistant to sorafenib treatment than those with small lysosomes (p<0.01), and that verapamil incubation can revert this resistance, especially if it is administered after drug pre-incubation. The findings of this study demonstrate the involvement of PGP-positive lysosomes in drug sequestration and MDR in HCC cell lines. The possibility of modulating this mechanism using PGP inhibitors could lead to the development of new targeted strategies to enhance HCC treatment.

No MeSH data available.


Related in: MedlinePlus

Chemoresistance assays.A) When treated with sorafenib, the cell lines with giant PGP-positive lysosomes (Hcc-1, HepG2, PLC/PRF/5 and HuH7) showed higher IC50 values than those with normal lysosomes (Hep3B and SNU475) (p<0.01). B) The HCC cell lines were incubated with different concentrations of sorafenib in order to verify their chemosensitivity (green lines). The cells with larger cytoplasmic vesicles were characterised by a curve with a sort of plateau of viability at sorafenib concentrations of between 5 and 20 µmol. One hour of verapamil pre-treatment used to inhibit ABC proteins before co-incubation with sorafenib and sunitinib increased the chemosensitivity of all of the cell lines (black curves). *p<0.01 green vs. black curves. One hour of sorafenib pre-treatment (red lines) before co-incubation with sorafenib and sunitinib enhanced treatment efficacy in comparison with verapamil pre-treatment in the cell lines carrying giant lysosomes. §p<0.05 red vs. black curves.
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pone-0114787-g009: Chemoresistance assays.A) When treated with sorafenib, the cell lines with giant PGP-positive lysosomes (Hcc-1, HepG2, PLC/PRF/5 and HuH7) showed higher IC50 values than those with normal lysosomes (Hep3B and SNU475) (p<0.01). B) The HCC cell lines were incubated with different concentrations of sorafenib in order to verify their chemosensitivity (green lines). The cells with larger cytoplasmic vesicles were characterised by a curve with a sort of plateau of viability at sorafenib concentrations of between 5 and 20 µmol. One hour of verapamil pre-treatment used to inhibit ABC proteins before co-incubation with sorafenib and sunitinib increased the chemosensitivity of all of the cell lines (black curves). *p<0.01 green vs. black curves. One hour of sorafenib pre-treatment (red lines) before co-incubation with sorafenib and sunitinib enhanced treatment efficacy in comparison with verapamil pre-treatment in the cell lines carrying giant lysosomes. §p<0.05 red vs. black curves.

Mentions: Interestingly, the cell lines with giant lysosomes (Hcc-1, HepG2, PLC/PRF/5 and HuH7) had higher IC50 values than the lines with small lysosomes (Hep3B and SNU475) (Fig. 9A). As expected, pre-incubation with verapamil increased the efficacy of sorafenib in comparison with sorafenib alone in all of the cell lines (P<0.05) (Fig. 9B). However, unexpectedly, pre-treatment with sorafenib was more efficacious than pre-treatment with verapamil in the cell lines with giant lysosomes (P<0.05), whereas no difference was observed in the Hep3B and SNU475 cell lines (Fig. 9B).


Giant Lysosomes as a Chemotherapy Resistance Mechanism in Hepatocellular Carcinoma Cells.

Colombo F, Trombetta E, Cetrangolo P, Maggioni M, Razini P, De Santis F, Torrente Y, Prati D, Torresani E, Porretti L - PLoS ONE (2014)

Chemoresistance assays.A) When treated with sorafenib, the cell lines with giant PGP-positive lysosomes (Hcc-1, HepG2, PLC/PRF/5 and HuH7) showed higher IC50 values than those with normal lysosomes (Hep3B and SNU475) (p<0.01). B) The HCC cell lines were incubated with different concentrations of sorafenib in order to verify their chemosensitivity (green lines). The cells with larger cytoplasmic vesicles were characterised by a curve with a sort of plateau of viability at sorafenib concentrations of between 5 and 20 µmol. One hour of verapamil pre-treatment used to inhibit ABC proteins before co-incubation with sorafenib and sunitinib increased the chemosensitivity of all of the cell lines (black curves). *p<0.01 green vs. black curves. One hour of sorafenib pre-treatment (red lines) before co-incubation with sorafenib and sunitinib enhanced treatment efficacy in comparison with verapamil pre-treatment in the cell lines carrying giant lysosomes. §p<0.05 red vs. black curves.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4262459&req=5

pone-0114787-g009: Chemoresistance assays.A) When treated with sorafenib, the cell lines with giant PGP-positive lysosomes (Hcc-1, HepG2, PLC/PRF/5 and HuH7) showed higher IC50 values than those with normal lysosomes (Hep3B and SNU475) (p<0.01). B) The HCC cell lines were incubated with different concentrations of sorafenib in order to verify their chemosensitivity (green lines). The cells with larger cytoplasmic vesicles were characterised by a curve with a sort of plateau of viability at sorafenib concentrations of between 5 and 20 µmol. One hour of verapamil pre-treatment used to inhibit ABC proteins before co-incubation with sorafenib and sunitinib increased the chemosensitivity of all of the cell lines (black curves). *p<0.01 green vs. black curves. One hour of sorafenib pre-treatment (red lines) before co-incubation with sorafenib and sunitinib enhanced treatment efficacy in comparison with verapamil pre-treatment in the cell lines carrying giant lysosomes. §p<0.05 red vs. black curves.
Mentions: Interestingly, the cell lines with giant lysosomes (Hcc-1, HepG2, PLC/PRF/5 and HuH7) had higher IC50 values than the lines with small lysosomes (Hep3B and SNU475) (Fig. 9A). As expected, pre-incubation with verapamil increased the efficacy of sorafenib in comparison with sorafenib alone in all of the cell lines (P<0.05) (Fig. 9B). However, unexpectedly, pre-treatment with sorafenib was more efficacious than pre-treatment with verapamil in the cell lines with giant lysosomes (P<0.05), whereas no difference was observed in the Hep3B and SNU475 cell lines (Fig. 9B).

Bottom Line: ABC expression analyses showed that the main ABC protein harboured by all of the cell lines was PGP, whose expression was not limited to the cell membrane but was also found on lysosomes.The findings of this study demonstrate the involvement of PGP-positive lysosomes in drug sequestration and MDR in HCC cell lines.The possibility of modulating this mechanism using PGP inhibitors could lead to the development of new targeted strategies to enhance HCC treatment.

View Article: PubMed Central - PubMed

Affiliation: Clinical Chemistry and Microbiology Laboratory, Flow Cytometry and Experimental Hepatology Service, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.

ABSTRACT
Despite continuous improvements in therapeutic protocols, cancer-related mortality is still one of the main problems facing public health. The main cause of treatment failure is multi-drug resistance (MDR: simultaneous insensitivity to different anti-cancer agents), the underlying molecular and biological mechanisms of which include the activity of ATP binding cassette (ABC) proteins and drug compartmentalisation in cell organelles. We investigated the expression of the main ABC proteins and the role of cytoplasmic vacuoles in the MDR of six hepatocellular carcinoma (HCC) cell lines, and confirmed the accumulation of the yellow anti-cancer drug sunitinib in giant (four lines) and small cytoplasmic vacuoles of lysosomal origin (two lines). ABC expression analyses showed that the main ABC protein harboured by all of the cell lines was PGP, whose expression was not limited to the cell membrane but was also found on lysosomes. MTT assays showed that the cell lines with giant lysosomes were more resistant to sorafenib treatment than those with small lysosomes (p<0.01), and that verapamil incubation can revert this resistance, especially if it is administered after drug pre-incubation. The findings of this study demonstrate the involvement of PGP-positive lysosomes in drug sequestration and MDR in HCC cell lines. The possibility of modulating this mechanism using PGP inhibitors could lead to the development of new targeted strategies to enhance HCC treatment.

No MeSH data available.


Related in: MedlinePlus