[1S04e] 14. Chemical Biotechnology - Part 3

5:00 PM - 5:15 PM JST(8:00 AM - 8:15 AM UTC)

[1Chemi-16] Detection of mechanically induced chloride ion efflux for evaluation of cancer cell invasiveness

○Ayana Yamagishi^1,2, Tsukuru Minamiki³, Toshihiro Takeshita⁴, Chikashi Nakamura^1,2 (1. Cell. Mol. Biotech. Res. Inst., AIST (Japan), 2. Grad. Sch. Eng., Tokyo Univ. Agric. Technol. (Japan), 3. Health Med. Res. Inst., AIST (Japan), 4. Integrated Research Center for Self-Care Technology, AIST (Japan))

Keywords:

Cancer,Chloride ion,FET sensor

Chloride intracellular channel 1 (CLIC1) is involved in cancer invasion and contributes to cell volume regulation through chloride efflux. During invasion, cancer cells experience mechanical compression while passing through narrow spaces. We hypothesized that mechanically induced Cl^- efflux via CLIC1 reduces cell volume, promoting invasion. Previously, we demonstrated that both mouse and human breast cancer cells exhibit Cl^- efflux upon application of external force using atomic force microscopy, and that this efflux correlates with cellular invasiveness (Anal. Chem., 93, 9032-5, 2021). To quantitatively evaluate cancer invasiveness based on this phenomenon, we developed a field-effect transistor (FET)-integrated MEMS cantilever device capable of directly detecting ions released during mechanical compression. An ethynylindole derivative (EnIND) was employed as the ion receptor for Cl^- detection. Utilizing the EnIND, the FET sensor achieved a detection limit of 10 pM for Cl^-. The FET sensor was integrated into a MEMS cantilever equipped with a piezoresistive element at its base for force measurement. A 10 µm bead attached to the cantilever tip served as a cell indenter, and Cl^- sensors were positioned adjacent to the bead. The device was operated under an inverted microscope to enable simultaneous mechanical compression and ion detection. Highly invasive human breast cancer cells MDA-MB-231, low-invasive breast cancer cells MCF-7, and normal mammary epithelial cells MCF10A were examined. Upon mechanical compression, an immediate decrease in FET drain current was observed in both breast cancer cell lines, indicating Cl^- export. In contrast, no significant signal change was detected in MCF10A cells. Moreover, the magnitude of signal change correlated with the invasiveness between MDA-MB-231 and MCF-7 cells. These results demonstrate that the FET-integrated MEMS cantilever enables detection of mechanically induced Cl^- efflux and provides a functional method to evaluate cancer cell invasiveness and distinguish cancer cells from normal cells. Furthermore, we applied mechanical stimulation to tumor tissues excised from a glioblastoma model mouse as well as to human colorectal cancer tissues, and measured the ions exported upon stimulation using this sensor. As a result, a clear response was detected in only tumor tissues. These findings suggest that this sensor can also be applied to the detection of tumor tissues.