Abstract 4828: Circulating tumor cells (CTCs) isolated from patients with metastatic breast cancer utilizing a sensitive microfluidic graphene oxide (GO) nanosheet device express markers of cancer stem cells

Breast cancers are driven by a subset of cells that display stem cell properties. These “cancer stem cells” (CSCs) mediate metastasis and contribute to treatment resistance. Many current CTC isolation technologies are limited in their sensitivity and are particularly inefficient at capturing cells which display an epithelial mesenchymal transition (EMT) phenotype which has been associated with CSCs. We have developed a sensitive microfluidic device using functionalized graphene oxide (GO) nanosheets to identify and isolate CTCs from patients with metastatic breast cancer. Unlike other CTC capture devices with microposts, the effective functionalized surface created by GO allows the device to be two-dimensional. The GO nanosheets were adsorbed onto the patterned gold surface and then chemically functionalized. Blood samples were collected into EDTA and AdnaGen tubes from patients with metastatic breast cancer and analyzed within 24 hours of blood sampling. Isolated CTCs were studied for expression of genes using a multiplex TaqMan-based qRT-PCR method. CTC preparations were checked for white blood cells (WBCs) contamination by examining CD45 expression and verifying that there was no or extremely low levels of CD45 expression in all of the processed samples. The majority of isolated CTCs showed mRNA expression of EMT markers including TGFβ and Vimentin at different levels among tested samples. In addition, markers of breast CSCs including CD44 + /CD24 - and ALDH1 + were observed in CTCs isolated from patients across the molecular subtypes of breast cancer. Interestingly, HER2 + CTCs were isolated from patients with HER2/neu - primary tumors. This is consistent with recent work from our group that demonstrated selective expression of HER2 in the CSC-like populations of luminal breast cancers occur independent of HER2 gene amplification. These studies demonstrate the feasibility of utilizing GO nanosheet microfluidic devices to isolate and molecularly characterize CTCs from metastatic breast cancer patients. Such liquid biopsies may be of particular value for following CSC populations for patients on therapeutic clinical trials. Citation Format: Shamileh Fouladdel, Hyeun Joong Yoon, Tae Hyun Kim, An Shi, Tahra Luther, Jill Hayden, Shawn G. Clouthier, Yadwinder S. Deol, Monika L. Burness, Daniel F. Hayes, Sunitha Nagrath, Ebrahim Azizi, Max S. Wicha. Circulating tumor cells (CTCs) isolated from patients with metastatic breast cancer utilizing a sensitive microfluidic graphene oxide (GO) nanosheet device express markers of cancer stem cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4828. doi:10.1158/1538-7445.AM2014-4828