Background Prostate carcinoma is the second leading cause of cancer related death in men in western contries; when the disease spreads outside the organ conventional therapies (radio, surgical and chemotherapy) are only palliative. In order to better control the disease progression, in the last then years scientists have discovered and validated various TAAs (tumor associated antigens), as targets of immunological treatments. In a previous study we have demonstrated that PSMA (Prostate Specific Membrane Antigen) can be a good target for immunotoxin therapy of prostate cancer cells; unfortunatly due to the tumor heterogeneity about 43% of the disseminated tumor cells in PCa patients do not show this marker/target. In this work we have verified the feasibility of using EpCAM (Epithelial Cell Adhesion Molecule) as a second target for a future multitarget approach in prostate cancer. Results As first step we have analyzed by flow cytometry the different expression levels of EpCAM antigen on LNCaP, DU145 and PC-3 cells. Using the mAb MOC31recognizing the Ag on the three cell lines, we have confirmed that LNCaP cells express the highest level of Ag and that PC-3 cells show the lowest expression level; the Ab specificity has been assayed on lymphoma Jurkat cells, where the MFI value is superimposable to the negative control MFI value. These analyses show that the PSMA negative DU145 cells expresses a good level of EpCAM antigen. This cells are insensitive to treatment with anti-PSMA IT, because they do not express PSMA Ag. When MOC31 Ab is conjugated to the RTA (Ricin A chain) toxin, the synthesized IT shows high cytotoxic efficacy against the LNCaP and DU145 cells; the activity on PC-3 cells is very low. MOC31-RTA IT is only 8-fold less toxic on DU145 cell than OKT9-RTA IT, a potent but not highly selective anti-TfnR immunotoxin. MOC31-RTA is effective not only on DU145 cells growing as a monolayer, but it also sterilizes DU145 spheroids (100-150um in diameter), an in vitro model of tumor micrometastasis.

EpCAM a possible target for immunotoxin treatments of PSMA positive and negative prostate cancer cells

FRACASSO, Giulio;CINGARLINI, Sara;ANSELMI, Cristina;GIGLIO, BARBARA;CREMONESE, Giorgia;COLOMBATTI, Marco
2008

Abstract

Background Prostate carcinoma is the second leading cause of cancer related death in men in western contries; when the disease spreads outside the organ conventional therapies (radio, surgical and chemotherapy) are only palliative. In order to better control the disease progression, in the last then years scientists have discovered and validated various TAAs (tumor associated antigens), as targets of immunological treatments. In a previous study we have demonstrated that PSMA (Prostate Specific Membrane Antigen) can be a good target for immunotoxin therapy of prostate cancer cells; unfortunatly due to the tumor heterogeneity about 43% of the disseminated tumor cells in PCa patients do not show this marker/target. In this work we have verified the feasibility of using EpCAM (Epithelial Cell Adhesion Molecule) as a second target for a future multitarget approach in prostate cancer. Results As first step we have analyzed by flow cytometry the different expression levels of EpCAM antigen on LNCaP, DU145 and PC-3 cells. Using the mAb MOC31recognizing the Ag on the three cell lines, we have confirmed that LNCaP cells express the highest level of Ag and that PC-3 cells show the lowest expression level; the Ab specificity has been assayed on lymphoma Jurkat cells, where the MFI value is superimposable to the negative control MFI value. These analyses show that the PSMA negative DU145 cells expresses a good level of EpCAM antigen. This cells are insensitive to treatment with anti-PSMA IT, because they do not express PSMA Ag. When MOC31 Ab is conjugated to the RTA (Ricin A chain) toxin, the synthesized IT shows high cytotoxic efficacy against the LNCaP and DU145 cells; the activity on PC-3 cells is very low. MOC31-RTA IT is only 8-fold less toxic on DU145 cell than OKT9-RTA IT, a potent but not highly selective anti-TfnR immunotoxin. MOC31-RTA is effective not only on DU145 cells growing as a monolayer, but it also sterilizes DU145 spheroids (100-150um in diameter), an in vitro model of tumor micrometastasis.
EpCAM; immunotoxin; prostate cancer
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11562/340888
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