The current state of the art of many high throughput cell-based assays, used for cancer research, drug development and determination of precision therapy, often requires growth on 2D surfaces and requires the time-consuming and labor-intensive culturing step. Furthermore, current assays use large cell populations, which can pose a challenge when working with the critically important, but small in number, cancer stem cells (CSCs). When investigating CSCs, differentiation can occur in as little as 1-2 cell divisions. Currently, no high throughput method exists to measure cytotoxic effects on suspended cancer stem cells. So it is desirable to have a high throughput assay that is sensitive to volume and shape changes in single suspended cells and small spheroids. In response to the limitation of current protocols, we are developing a cell magnetorotation method, based on asynchronous magnetic bead rotation (AMBR), that is sensitive to single-cell changes, and that will allow for rapid growth and cytotoxicity analysis of individual suspended cells and spheroids. Due to its submicroscopic resolution, high throughput, and short observation time, we anticipate that this AMBR assay will drastically reduce the culture step time, the overall time to results, and the number of cells needed for such an assay. For the preliminary validation of this new approach we selected to investigate single cells, single stem cells and single spheroids relating to prostate cancer. We set up a collaboration using the nanotechnology and nanomedicine expertise of the Kopelman Lab and the prostate cancer and drug sensitivity expertise of the Pienta Lab. Based on preliminary single cancer cell results, we hypothesize that the volumetric changes, resulting from the response to chemotherapy agents by cancer cells and spheroids, can be accurately and sensitively monitored. Furthermore, due to the combined sensitivity, speed and simplicity of the proposed approach, the typically very small number of stem cells can be tested rapidly, before their turning into a heterogeneous population. This will enable rapid drug sensitivity tests on cancer stem cells and on spheroids containing cancer stem cells, leading to a fast and smart selection protocol for therapeutic agents that can be tailored to a specific patient. We plan to achieve growth and cytotoxicity demonstration measurements on individual prostate cancer and cancer stem cells. We also plan to demonstrate that the AMBR method can be used to measure the growth of prostate cancer spheroids and their response to the cytotoxic agent docetaxel. Our long-term objective is to develop an assay device that will detect target cells directly in liquid clinical specimens (circulating tumor cells from patient blood) and provide automated results, with no manual steps, for personalized identification and drug sensitivity testing, for any form of cancer.
This proposal is relevant to public health because determining the optimum treatment for the individual patient is of prime importance in medicine, and particularly when it comes to cancer cases. A new approach, based on cell magnetorotation, enables drug sensitivity tests with higher sensitivity, throughput, speed and fidelity. Therefore, this proposal is relevant to the part of NIH's mission for developing medical discoveries that improve human health.
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| Hecht, Ariel; Commiskey, Patrick; Shah, Nicholas et al. (2013) Bead assembly magnetorotation as a signal transduction method for protein detection. Biosens Bioelectron 48:26-32 |
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