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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

Immunofluorescence staining of cell organelles.Vesicle membranes (arrowheads) stained positive for anti-LAMP1 antibody (green). All of the other antibodies against organelle proteins were negative (data not shown). (A) Hcc-1, (B) HepG2, (C) PLC/PRF/5, (D) HuH7, (E) Hep3B, and (F) SNU475. Nuclei were stained with DAPI (blue). Original magnification 20x.
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pone-0114787-g004: Immunofluorescence staining of cell organelles.Vesicle membranes (arrowheads) stained positive for anti-LAMP1 antibody (green). All of the other antibodies against organelle proteins were negative (data not shown). (A) Hcc-1, (B) HepG2, (C) PLC/PRF/5, (D) HuH7, (E) Hep3B, and (F) SNU475. Nuclei were stained with DAPI (blue). Original magnification 20x.

Mentions: The intra-cellular vesicles stained positively for LAMP-1 (Fig. 4) but negatively for VMP1, PMP70 and PDI (data not shown), thus indicating their lysosomal nature. Western blot analysis confirmed a higher expression of LAMP-1 in those cell lines carrying giant lysosomes as compared to those characterized by small lysosomes (p<0.05) (Fig. 5).


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)

Immunofluorescence staining of cell organelles.Vesicle membranes (arrowheads) stained positive for anti-LAMP1 antibody (green). All of the other antibodies against organelle proteins were negative (data not shown). (A) Hcc-1, (B) HepG2, (C) PLC/PRF/5, (D) HuH7, (E) Hep3B, and (F) SNU475. Nuclei were stained with DAPI (blue). Original magnification 20x.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0114787-g004: Immunofluorescence staining of cell organelles.Vesicle membranes (arrowheads) stained positive for anti-LAMP1 antibody (green). All of the other antibodies against organelle proteins were negative (data not shown). (A) Hcc-1, (B) HepG2, (C) PLC/PRF/5, (D) HuH7, (E) Hep3B, and (F) SNU475. Nuclei were stained with DAPI (blue). Original magnification 20x.
Mentions: The intra-cellular vesicles stained positively for LAMP-1 (Fig. 4) but negatively for VMP1, PMP70 and PDI (data not shown), thus indicating their lysosomal nature. Western blot analysis confirmed a higher expression of LAMP-1 in those cell lines carrying giant lysosomes as compared to those characterized by small lysosomes (p<0.05) (Fig. 5).

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