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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

Sunitinib treatments.Representative pictures of the effect of sunitinib treatments on the HepG2 (with giant lysosomes) and SNU475 cell lines (with normal lysosomes). The rows show the treatment conditions: 1) Sunitinib 12 µM alone for 12 hours; 2) One hour of pre-incubation with verapamil 20 µM followed by the co-incubation of verapamil 20 µM and sunitinib 12 µM for 12 hours; 3) One hour of pre-incubation with sunitinib 12 µM followed by the co-incubation of verapamil 20 µM and sunitinib 12 µM for 12 hours. It can be seen that, in both cell lines, cell death after 12 hours’ treatment was greater in the cells pre-treated with sunitinib.
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pone-0114787-g010: Sunitinib treatments.Representative pictures of the effect of sunitinib treatments on the HepG2 (with giant lysosomes) and SNU475 cell lines (with normal lysosomes). The rows show the treatment conditions: 1) Sunitinib 12 µM alone for 12 hours; 2) One hour of pre-incubation with verapamil 20 µM followed by the co-incubation of verapamil 20 µM and sunitinib 12 µM for 12 hours; 3) One hour of pre-incubation with sunitinib 12 µM followed by the co-incubation of verapamil 20 µM and sunitinib 12 µM for 12 hours. It can be seen that, in both cell lines, cell death after 12 hours’ treatment was greater in the cells pre-treated with sunitinib.

Mentions: Finally, 12-hour cell mortality, monitored by optical microscopy, was greater in the cells pre-incubated with sunitinib than in those pre-incubated with verapamil (Fig. 10).


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)

Sunitinib treatments.Representative pictures of the effect of sunitinib treatments on the HepG2 (with giant lysosomes) and SNU475 cell lines (with normal lysosomes). The rows show the treatment conditions: 1) Sunitinib 12 µM alone for 12 hours; 2) One hour of pre-incubation with verapamil 20 µM followed by the co-incubation of verapamil 20 µM and sunitinib 12 µM for 12 hours; 3) One hour of pre-incubation with sunitinib 12 µM followed by the co-incubation of verapamil 20 µM and sunitinib 12 µM for 12 hours. It can be seen that, in both cell lines, cell death after 12 hours’ treatment was greater in the cells pre-treated with sunitinib.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0114787-g010: Sunitinib treatments.Representative pictures of the effect of sunitinib treatments on the HepG2 (with giant lysosomes) and SNU475 cell lines (with normal lysosomes). The rows show the treatment conditions: 1) Sunitinib 12 µM alone for 12 hours; 2) One hour of pre-incubation with verapamil 20 µM followed by the co-incubation of verapamil 20 µM and sunitinib 12 µM for 12 hours; 3) One hour of pre-incubation with sunitinib 12 µM followed by the co-incubation of verapamil 20 µM and sunitinib 12 µM for 12 hours. It can be seen that, in both cell lines, cell death after 12 hours’ treatment was greater in the cells pre-treated with sunitinib.
Mentions: Finally, 12-hour cell mortality, monitored by optical microscopy, was greater in the cells pre-incubated with sunitinib than in those pre-incubated with verapamil (Fig. 10).

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