Abstract 3794: Selective isolation of epithelial to mesenchymal transitioned circulating tumor cells in NSCLC using novel magnetic nanocubes
Authors: Suresh Dhananjay , Ghoshdastidar Shreya , Mukherjee Soumavo , Gangula Abilash , Upendran Anandhi , Kannan Raghuraman 
Published: July 2017

Abstract
The 5-year survival rate for early to advanced NSCLC patients is 10-5%. Once the tumor metastasizes, the survival rate often drops below 1%. One of the major challenges is to select the patient for appropriate therapy, and the selection process involves invasive biopsy that is difficult to recurrently perform during treatment. Recent studies have shown that liquid biopsy is an attractive alternative. Liquid biopsy involves analysis of either CTCs or ctDNA to understand the tumor therapy. Isolating entire tumor cells provide an opportunity to perform whole genome sequencing for in depth understanding of the tumor. However, frequent changes in cancer signaling and acquired mutations during treatment lead to drug resistance that cannot be diagnosed using current CTC techniques. These oncogenic biochemical modifications that are often associated with metastasis involve upregulation of epithelial to mesenchymal transition (EMT) pathway that change the elasticity of tumor cells for easy shedding into the blood stream. Consequently, EMT transition leads to depletion in epithelial markers such as EpCAM and cytokeratin that are to be targeted. This effect largely limits the use of present technologies utilizing EpCAM as a marker to isolate the CTCs. We hypothesized that these cells can be captured by targeting surface markers that are overexpressed in EM transitioned CTCs. For example, markers such as EGFR and HER2 have been shown to be overexpressed pre and post EMT tumors and therefore can present as a new strategy for non-invasive diagnosis before and during treatment. In this study we have shown that EGFR and HER2 receptors are overexpressed in EGFR and KRAS mutated NSCLC cells. We artificially activated EMT in NSCLC cells and compared the surface biomarker concentrations. Furthermore, we used protein analysis data using western blotting to identify our targets after EMT. Based on the biomarker concentrations, we designed and developed magnetic nanocubes (MNC) surface attached with antibodies to target the selected biomarkers to capture EMT CTCs. The capture efficiency of these magnetic nanocubes was compared in multiple cell lines (HCC827 and A549). Overall we could achieve capture as low as 10 spiked cells in our study. In conclusion, cancer markers such as EGFR and HER-2 that are highly expressed in tumors, once shed as CTCs can be targeted for diagnosis. Therefore, we have developed a novel method to capture EMT CTCs with high selectivity and this method presents a minimally-invasive method for real-time monitoring of patients during drug treatment.
Citation Format: Dhananjay Suresh, Shreya Ghoshdastidar, Soumavo Mukherjee, Abilash Gangula, Anandhi Upendran, Raghuraman Kannan. Selective isolation of epithelial to mesenchymal transitioned circulating tumor cells in NSCLC using novel magnetic nanocubes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3794. doi:10.1158/1538-7445.AM2017-3794