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Phosphatidylserine-selective targeting and anticancer effects of SapC-DOPS nanovesicles on brain tumors.

Blanco VM, Chu Z, Vallabhapurapu SD, Sulaiman MK, Kendler A, Rixe O, Warnick RE, Franco RS, Qi X - Oncotarget (2014)

Bottom Line: These actions are a consequence of the affinity of SapC-DOPS for phosphatidylserine, an acidic phospholipid abundantly present in the outer membrane of a variety of tumor cells and tumor-associated vasculature.In this study, we first characterize SapC-DOPS bioavailability and antitumor effects on human glioblastoma xenografts, and confirm SapC-DOPS specificity towards phosphatidylserine by showing that glioblastoma targeting is abrogated after in vivo exposure to lactadherin, which binds phosphatidylserine with high affinity.Taken together, these results support the potential of SapC-DOPS for the diagnosis and therapy of primary and metastatic brain tumors.

View Article: PubMed Central - PubMed

Affiliation: Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio.

ABSTRACT
Brain tumors, either primary (e.g., glioblastoma multiforme) or secondary (metastatic), remain among the most intractable and fatal of all cancers. We have shown that nanovesicles consisting of Saposin C (SapC) and dioleylphosphatidylserine (DOPS) are able to effectively target and kill cancer cells both in vitro and in vivo. These actions are a consequence of the affinity of SapC-DOPS for phosphatidylserine, an acidic phospholipid abundantly present in the outer membrane of a variety of tumor cells and tumor-associated vasculature. In this study, we first characterize SapC-DOPS bioavailability and antitumor effects on human glioblastoma xenografts, and confirm SapC-DOPS specificity towards phosphatidylserine by showing that glioblastoma targeting is abrogated after in vivo exposure to lactadherin, which binds phosphatidylserine with high affinity. Second, we demonstrate that SapC-DOPS selectively targets brain metastases-forming cancer cells both in vitro, in co-cultures with human astrocytes, and in vivo, in mouse models of brain metastases derived from human breast or lung cancer cells. Third, we demonstrate that SapC-DOPS have cytotoxic activity against metastatic breast cancer cells in vitro, and prolong the survival of mice harboring brain metastases. Taken together, these results support the potential of SapC-DOPS for the diagnosis and therapy of primary and metastatic brain tumors.

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Tumor selective targeting of SapC-DOPS-CVM in co-cultured astrocytes and tumor cells(A) Normal human astrocytes and MDA-MB-231-luc-D3H2LN co-culture. Astrocytes (green) were labeled with PKH67. Cultures were exposed to SapC-DOPS-CVM (red) for 30 min. In the image at the bottom PKH67 fluorescence was omitted. (B) Quantification of SapC-DOPS-CVM uptake in co-cultured cells (pooled data from 10 microphotographs per culture; n=3 cultures). (C) Phosphatidylserine expression in cultured human astrocytes and MDA-MB-231-luc-D3H2LN cells, as assessed by flow cytometry using annexin V-FITC; n=3 cultures. **p<0.001. Scale bar = 20 μm.
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Figure 5: Tumor selective targeting of SapC-DOPS-CVM in co-cultured astrocytes and tumor cells(A) Normal human astrocytes and MDA-MB-231-luc-D3H2LN co-culture. Astrocytes (green) were labeled with PKH67. Cultures were exposed to SapC-DOPS-CVM (red) for 30 min. In the image at the bottom PKH67 fluorescence was omitted. (B) Quantification of SapC-DOPS-CVM uptake in co-cultured cells (pooled data from 10 microphotographs per culture; n=3 cultures). (C) Phosphatidylserine expression in cultured human astrocytes and MDA-MB-231-luc-D3H2LN cells, as assessed by flow cytometry using annexin V-FITC; n=3 cultures. **p<0.001. Scale bar = 20 μm.

Mentions: After characterizing the targeting efficacy and bioavailability of SapC-DOPS in a primary brain cancer (GBM) model, we evaluated its ability both in vitro and in vivo to target cancer cells with brain metastasis potential. To this end, we first established an in vitro co-culture system comprising normal human astrocytes (HA) and metastatic breast cancer (MDA-MB-231-luc-D3H2LN) cells and compared SapC-DOPS uptake in both cell types after short (30 min) incubation. Fig. 5 illustrates and summarizes SapC-DOPS-CVM uptake (A; red fluorescence) and quantification data (B) for both cell types. Binding and uptake of SapC-DOPS-CVM was significantly higher in cancer cells. In line with the results presented above, this selectivity is likely to be a consequence of the elevated phosphatidylserine exposure levels exhibited by MDA-MB-231-luc-D3H2LN cells, as compared with those of normal astrocytes (Fig. 5C). Next, we evaluated the cytotoxicity of SapC-DOPS toward MDA-MB-231-luc-D3H2LN cells using the MTT cell viability assay. After 72 hs treatment, the assay revealed that SapC-DOPS killed tumor cells with an IC50 of 25.2 ± 1.5 μM (n = 3).


Phosphatidylserine-selective targeting and anticancer effects of SapC-DOPS nanovesicles on brain tumors.

Blanco VM, Chu Z, Vallabhapurapu SD, Sulaiman MK, Kendler A, Rixe O, Warnick RE, Franco RS, Qi X - Oncotarget (2014)

Tumor selective targeting of SapC-DOPS-CVM in co-cultured astrocytes and tumor cells(A) Normal human astrocytes and MDA-MB-231-luc-D3H2LN co-culture. Astrocytes (green) were labeled with PKH67. Cultures were exposed to SapC-DOPS-CVM (red) for 30 min. In the image at the bottom PKH67 fluorescence was omitted. (B) Quantification of SapC-DOPS-CVM uptake in co-cultured cells (pooled data from 10 microphotographs per culture; n=3 cultures). (C) Phosphatidylserine expression in cultured human astrocytes and MDA-MB-231-luc-D3H2LN cells, as assessed by flow cytometry using annexin V-FITC; n=3 cultures. **p<0.001. Scale bar = 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4196187&req=5

Figure 5: Tumor selective targeting of SapC-DOPS-CVM in co-cultured astrocytes and tumor cells(A) Normal human astrocytes and MDA-MB-231-luc-D3H2LN co-culture. Astrocytes (green) were labeled with PKH67. Cultures were exposed to SapC-DOPS-CVM (red) for 30 min. In the image at the bottom PKH67 fluorescence was omitted. (B) Quantification of SapC-DOPS-CVM uptake in co-cultured cells (pooled data from 10 microphotographs per culture; n=3 cultures). (C) Phosphatidylserine expression in cultured human astrocytes and MDA-MB-231-luc-D3H2LN cells, as assessed by flow cytometry using annexin V-FITC; n=3 cultures. **p<0.001. Scale bar = 20 μm.
Mentions: After characterizing the targeting efficacy and bioavailability of SapC-DOPS in a primary brain cancer (GBM) model, we evaluated its ability both in vitro and in vivo to target cancer cells with brain metastasis potential. To this end, we first established an in vitro co-culture system comprising normal human astrocytes (HA) and metastatic breast cancer (MDA-MB-231-luc-D3H2LN) cells and compared SapC-DOPS uptake in both cell types after short (30 min) incubation. Fig. 5 illustrates and summarizes SapC-DOPS-CVM uptake (A; red fluorescence) and quantification data (B) for both cell types. Binding and uptake of SapC-DOPS-CVM was significantly higher in cancer cells. In line with the results presented above, this selectivity is likely to be a consequence of the elevated phosphatidylserine exposure levels exhibited by MDA-MB-231-luc-D3H2LN cells, as compared with those of normal astrocytes (Fig. 5C). Next, we evaluated the cytotoxicity of SapC-DOPS toward MDA-MB-231-luc-D3H2LN cells using the MTT cell viability assay. After 72 hs treatment, the assay revealed that SapC-DOPS killed tumor cells with an IC50 of 25.2 ± 1.5 μM (n = 3).

Bottom Line: These actions are a consequence of the affinity of SapC-DOPS for phosphatidylserine, an acidic phospholipid abundantly present in the outer membrane of a variety of tumor cells and tumor-associated vasculature.In this study, we first characterize SapC-DOPS bioavailability and antitumor effects on human glioblastoma xenografts, and confirm SapC-DOPS specificity towards phosphatidylserine by showing that glioblastoma targeting is abrogated after in vivo exposure to lactadherin, which binds phosphatidylserine with high affinity.Taken together, these results support the potential of SapC-DOPS for the diagnosis and therapy of primary and metastatic brain tumors.

View Article: PubMed Central - PubMed

Affiliation: Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio.

ABSTRACT
Brain tumors, either primary (e.g., glioblastoma multiforme) or secondary (metastatic), remain among the most intractable and fatal of all cancers. We have shown that nanovesicles consisting of Saposin C (SapC) and dioleylphosphatidylserine (DOPS) are able to effectively target and kill cancer cells both in vitro and in vivo. These actions are a consequence of the affinity of SapC-DOPS for phosphatidylserine, an acidic phospholipid abundantly present in the outer membrane of a variety of tumor cells and tumor-associated vasculature. In this study, we first characterize SapC-DOPS bioavailability and antitumor effects on human glioblastoma xenografts, and confirm SapC-DOPS specificity towards phosphatidylserine by showing that glioblastoma targeting is abrogated after in vivo exposure to lactadherin, which binds phosphatidylserine with high affinity. Second, we demonstrate that SapC-DOPS selectively targets brain metastases-forming cancer cells both in vitro, in co-cultures with human astrocytes, and in vivo, in mouse models of brain metastases derived from human breast or lung cancer cells. Third, we demonstrate that SapC-DOPS have cytotoxic activity against metastatic breast cancer cells in vitro, and prolong the survival of mice harboring brain metastases. Taken together, these results support the potential of SapC-DOPS for the diagnosis and therapy of primary and metastatic brain tumors.

Show MeSH
Related in: MedlinePlus