Use Of Doxorubicin For Radioiodine Targeted Therapy Of Treatment Resistant Metastatic Breast Cancer, Hepatocellular Cancer, And Colon Cancer

3025 Introduction: Sodium iodide symporter (NIS) is expressed in human hepatocellular carcinoma (HCA) and certain breast carcinomas (BCA), however, the effective treatment of these cancers using radioactive iodine (RAI) is contingent upon constitutive and stronger expression of NIS. It has been shown that doxorubicin induces selective expression of NIS in HCA by activation of p63 and p73 binding to NIS promoter, leading to an increased expression of NIS mRNA and protein in HCA cells but not in primary human hepatocytes. We tested the hypothesis that doxorubicin can be used effectively to upregulate NIS-expression in HCA, BCA and Colon Carcinoma (CCA). This proposal was tested in the following three specific aims: Aim 1) To demonstrate that doxorubicin can be used viably on cultured HCA, BCA, and CCA cells. Aim 2) To demonstrate that doxorubicin can selectively induce NIS expression in BCA cells. Aim 3) To demonstrate that doxorubicin can selectively induce NIS expression in CCA cells. We were able to successfully culture HCA, BCA, and CCA cells in vitro and treat these cells with varying concentrations of doxorubicin without loss of cell viability. We were then able to extract the total proteins from BCA and CCA cells respectively and perform NIS protein expression studies using western blot. Our results demonstrate that HCA, BCA, and CCA cells can be treated with doxorubicin without loss of cell viability and doxorubicin upregulates the expression of NIS protein strongly in BCA cells (Fig. 1) and at low levels in CCA cells (Fig. 2). The findings of these studies will enable us to investigate further the use of radioiodine to treat these deadly cancers which can significantly contribute to our efforts in improving patient prognosis. Figure 1.Western blot results demonstrates that doxorubicin upregulates sodium iodide symporter (NIS) in MDA-MB231 breast cancer cells. MDA-MB231 cells were not treated (0) or treated with 0.2µM, 2µM, or 20µM doxorubicin hydrochloride for 48 hours. After equal loading, total cell proteins were separated on SDS-polyacrylamide gel and subsequently transferred to nitrocellulose membrane. The NIS protein levels were determined by western blot using goat anti-NIS primary antibody and rabbit antigoat secondary antibody. Figure 2. Visualization of sodium iodide symporter at low levels in the 2 uM doxorubicin-treated colon cancer sample. NaI symporter expression in SW620 cells was assessed by treating SW620 cells with doxorubicin at 2μM for 48 hrs, followed by washing with PBS. Cells were lysed in lysis buffer and 1μg of protein was resolved by Polyacrylamide Gel Electrophoresis. Proteins were transferred to a Polyvinylidene difluoride membrane, probed with a rabbit anti-NIS polyclonal IgG antibody and mmunodetected using a secondary rabbit antibody and detected chromogenically using TMB substrate.