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Tumor Suppressor WWOX inhibits osteosarcoma metastasis by modulating RUNX2 function.

Del Mare S, Aqeilan RI - Sci Rep (2015)

Bottom Line: We recently demonstrated that WW domain-containing oxidoreductase (WWOX) is frequently inactivated in human OS and that WWOX restoration in WWOX-negative OS cells suppresses tumorigenicity.Mechanistically, WWOX function is associated with reduced levels of RUNX2 metastatic target genes implicated in adhesion and motility.Our results suggest that WWOX plays a critical role in determining the aggressive phenotype of OS, and its expression could be an attractive therapeutic target to combat this devastating adolescent disease.

View Article: PubMed Central - PubMed

Affiliation: The Lautenberg Center for Immunology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Israel 91220.

ABSTRACT
Osteosarcoma (OS) is among the most frequently occurring primary bone tumors, primarily affecting adolescents and young adults. This malignant osteoid forming tumor is characterized by its metastatic potential, mainly to lungs. We recently demonstrated that WW domain-containing oxidoreductase (WWOX) is frequently inactivated in human OS and that WWOX restoration in WWOX-negative OS cells suppresses tumorigenicity. Of note, WWOX levels are reduced in paired OS samples of post-treatment metastastectomies as compared to pre-treatment biopsies suggesting that decreased WWOX levels are associated with a more aggressive phenotype at the metastatic site. Nevertheless, little is known about WWOX function in OS metastasis. Here, we investigated the role of tumor suppressor WWOX in suppressing pulmonary OS metastasis both in vitro and in vivo. We demonstrated that ectopic expression of WWOX in OS cells, HOS and LM-7, inhibits OS invasion and cell migration in vitro. Furthermore, WWOX expression reduced tumor burden in vivo and inhibited metastases' seeding and colonization. Mechanistically, WWOX function is associated with reduced levels of RUNX2 metastatic target genes implicated in adhesion and motility. Our results suggest that WWOX plays a critical role in determining the aggressive phenotype of OS, and its expression could be an attractive therapeutic target to combat this devastating adolescent disease.

No MeSH data available.


Related in: MedlinePlus

WWOX expression inhibited OS metastatic potential when injected intravenously.(A,B) HOS-EV-GFP and HOS-WWOX-GFP (A,B) and LM7 -EV-GFP and LM7-GFP-WWOX cells (C,D) were injected into the lateral tail vein (IV) of NOD/SCID mice (5 per group). The formation of metastasis in the lungs was detected after 8 weeks from the injection. Images obtained by fluorescent microscopy displaying macrometastasis in HOS and LM7 cells are shown. Quantification of micro and macro –metastasis (as in Fig. 2C) is shown in (B,D).
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f3: WWOX expression inhibited OS metastatic potential when injected intravenously.(A,B) HOS-EV-GFP and HOS-WWOX-GFP (A,B) and LM7 -EV-GFP and LM7-GFP-WWOX cells (C,D) were injected into the lateral tail vein (IV) of NOD/SCID mice (5 per group). The formation of metastasis in the lungs was detected after 8 weeks from the injection. Images obtained by fluorescent microscopy displaying macrometastasis in HOS and LM7 cells are shown. Quantification of micro and macro –metastasis (as in Fig. 2C) is shown in (B,D).

Mentions: We next determined whether WWOX impact on invasion and metastasis was also attributable to effects on later steps of the invasion-metastasis cascade, independent of its influence on local invasion (IT model). Thus we injected WWOX-expressing HOS or LM-7 cells directly on the circulation of mice, thereby circumventing the initial steps of local invasion and intravasation. To this end, GFP-fluorescent OS cells were injected intravenously (IV) and formation of GFP+ metastatic lung nodules was assessed. Two months after tail-vain injection, WWOX-expressing HOS cells generated fewer lung metastases than did controls (Fig. 3A). In fact, all mice injected with HOS-EV developed macrometastasis (60%) and micrometastasis (40%) whereas only 1 out of 5 (20%) of mice bearing HOS-WWOX cells in the IV model develop micrometastasis (Fig. 3B). Similar results were obtained with the metastatic LM7 OS cell line when injected intravenously (Fig. 3C,D). Such effects on lesion size implied that WWOX affects metastatic colonization (Fig. 3) in addition to its influences on local invasion events (Fig. 2). These data are also consistent with WWOX effect on primary tumor growth [(Fig. 2A) and12] indicating that WWOX could affect cell growth as well as invasion.


Tumor Suppressor WWOX inhibits osteosarcoma metastasis by modulating RUNX2 function.

Del Mare S, Aqeilan RI - Sci Rep (2015)

WWOX expression inhibited OS metastatic potential when injected intravenously.(A,B) HOS-EV-GFP and HOS-WWOX-GFP (A,B) and LM7 -EV-GFP and LM7-GFP-WWOX cells (C,D) were injected into the lateral tail vein (IV) of NOD/SCID mice (5 per group). The formation of metastasis in the lungs was detected after 8 weeks from the injection. Images obtained by fluorescent microscopy displaying macrometastasis in HOS and LM7 cells are shown. Quantification of micro and macro –metastasis (as in Fig. 2C) is shown in (B,D).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542681&req=5

f3: WWOX expression inhibited OS metastatic potential when injected intravenously.(A,B) HOS-EV-GFP and HOS-WWOX-GFP (A,B) and LM7 -EV-GFP and LM7-GFP-WWOX cells (C,D) were injected into the lateral tail vein (IV) of NOD/SCID mice (5 per group). The formation of metastasis in the lungs was detected after 8 weeks from the injection. Images obtained by fluorescent microscopy displaying macrometastasis in HOS and LM7 cells are shown. Quantification of micro and macro –metastasis (as in Fig. 2C) is shown in (B,D).
Mentions: We next determined whether WWOX impact on invasion and metastasis was also attributable to effects on later steps of the invasion-metastasis cascade, independent of its influence on local invasion (IT model). Thus we injected WWOX-expressing HOS or LM-7 cells directly on the circulation of mice, thereby circumventing the initial steps of local invasion and intravasation. To this end, GFP-fluorescent OS cells were injected intravenously (IV) and formation of GFP+ metastatic lung nodules was assessed. Two months after tail-vain injection, WWOX-expressing HOS cells generated fewer lung metastases than did controls (Fig. 3A). In fact, all mice injected with HOS-EV developed macrometastasis (60%) and micrometastasis (40%) whereas only 1 out of 5 (20%) of mice bearing HOS-WWOX cells in the IV model develop micrometastasis (Fig. 3B). Similar results were obtained with the metastatic LM7 OS cell line when injected intravenously (Fig. 3C,D). Such effects on lesion size implied that WWOX affects metastatic colonization (Fig. 3) in addition to its influences on local invasion events (Fig. 2). These data are also consistent with WWOX effect on primary tumor growth [(Fig. 2A) and12] indicating that WWOX could affect cell growth as well as invasion.

Bottom Line: We recently demonstrated that WW domain-containing oxidoreductase (WWOX) is frequently inactivated in human OS and that WWOX restoration in WWOX-negative OS cells suppresses tumorigenicity.Mechanistically, WWOX function is associated with reduced levels of RUNX2 metastatic target genes implicated in adhesion and motility.Our results suggest that WWOX plays a critical role in determining the aggressive phenotype of OS, and its expression could be an attractive therapeutic target to combat this devastating adolescent disease.

View Article: PubMed Central - PubMed

Affiliation: The Lautenberg Center for Immunology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Israel 91220.

ABSTRACT
Osteosarcoma (OS) is among the most frequently occurring primary bone tumors, primarily affecting adolescents and young adults. This malignant osteoid forming tumor is characterized by its metastatic potential, mainly to lungs. We recently demonstrated that WW domain-containing oxidoreductase (WWOX) is frequently inactivated in human OS and that WWOX restoration in WWOX-negative OS cells suppresses tumorigenicity. Of note, WWOX levels are reduced in paired OS samples of post-treatment metastastectomies as compared to pre-treatment biopsies suggesting that decreased WWOX levels are associated with a more aggressive phenotype at the metastatic site. Nevertheless, little is known about WWOX function in OS metastasis. Here, we investigated the role of tumor suppressor WWOX in suppressing pulmonary OS metastasis both in vitro and in vivo. We demonstrated that ectopic expression of WWOX in OS cells, HOS and LM-7, inhibits OS invasion and cell migration in vitro. Furthermore, WWOX expression reduced tumor burden in vivo and inhibited metastases' seeding and colonization. Mechanistically, WWOX function is associated with reduced levels of RUNX2 metastatic target genes implicated in adhesion and motility. Our results suggest that WWOX plays a critical role in determining the aggressive phenotype of OS, and its expression could be an attractive therapeutic target to combat this devastating adolescent disease.

No MeSH data available.


Related in: MedlinePlus