A novel anti-cancer drug sensitivity testing (DST) approach was developed based on in vitro single-cell Raman spectrum intensity (RSI). Generally, the intensity of Raman spectra (RS) for a single living cell treated with drugs positively relates to the sensitivity of the cells to the drugs. In this study, five cancer cell lines (BGC 823, SGC 7901, MGC 803, AGS, and NCI-N87) were exposed to three cytotoxic compounds or to combinations of these compounds, and then they were evaluated for their responses with RSI. The results of RSI were consistent with conventional DST methods. The parametric correlation coefficient for the RSI and Methylthiazolyl tetrazolium assay (MTT) was 0.8558 ± 0.0850, and the coefficient of determination was calculated as R2 = 0.9529 ± 0.0355 for fitting the dose–response curve. Moreover, RSI data for NCI-N87 cells treated by trastuzumab, everolimus (cytostatic), and these drugs in combination demonstrated that the RSI method was suitable for testing the sensitivity of cytostatic drugs. Furthermore, a heterogeneity coefficient H was introduced for quantitative characterization of the heterogeneity of cancer cells treated by drugs. The largest possible variance between RSs of cancer cells were quantitatively obtained using eigenvalues of principal component analysis (PCA). The ratio of H between resistant cells and sensitive cells was greater than 1.5, which suggested the H-value was effective to describe the heterogeneity of cancer cells. Briefly, the RSI method might be a powerful tool for simple and rapid detection of the sensitivity of tumor cells to anti-cancer drugs and the heterogeneity of their responses to these drugs.
Raman
optical tweezers (ROT) as a label-free technique plays an
important role in single-cell study such as heterogeneity of tumor
and microbial cells. Herein we designed a chip utilizing ROT to isolate
a specific single cell. The chip was made from a polydimethylsiloxane
(PDMS) slab and formed into a gourd-shaped reservoir with a connected
channel on a cover glass. On the chip an individual cell could be
isolated from a cell crowd and then extracted with ∼0.5 μL
of phosphate-buffered saline (PBS) via pipet immediately after Raman
spectral measurements of the same cell. As verification, we separated
four different type of cells including BGC823 gastric cancer cells,
erythrocytes, lymphocytes, and E. coli cells and
quantifiably characterized the heterogeneity of the cancer cells,
leukocyte subtype, and erythrocyte status, respectively. The average
time of identifying and isolating a specific cell was 3 min. Cell
morphology comparison and viability tests showed that the successful
rate of single-cell isolation was about 90%. Thus, we believe our
platform could further couple other single-cell techniques such as
single-cell sequencing and become a multiperspective analytical approach
at the level of a single cell.
Single-cell
analysis has become a state-of-art approach to heterogeneity
profiling in tumor cells. Herein, we realize a kind of single-cell
multimodal analytical approach by combining single-cell RNA sequencing
(scRNA-seq) with Raman optical tweezers (ROT), a label-free single-cell
identification and isolation technique, and apply it to investigate
drug sensitivity. The drug sensitivity of human BGC823 gastric cancer
cells toward different drugs, paclitaxel and sodium dichloroacetate,
was distinguished in the conjoint analytical way including morphology
monitoring, Raman identification, and transcriptomic profiling. Each
individual BGC823 cancer cell was measured by Raman spectroscopy,
then nondestructively isolated out by ROT, and finally RNA-sequenced.
Our results demonstrate each analytical mode can reflect cell response
to the drugs from different perspectives and is consistent and complementary
with each other. Therefore, we believe the multimodal analytical approach
offers an access to comprehensive characterizations of the unicellular
complexity, which especially makes sense for studying tumor heterogeneity
or a desired special cell from a mixture cell sample such as whole
blood.
Nucleated red blood cell (NRBC) as a type of rare cells present in an adult’s peripheral blood is concerned in hematology, intensive care medicine and prenatal diagnostics. However, it is...
Correction for ‘Fast label-free recognition of NRBCs by deep-learning visual object detection and single-cell Raman spectroscopy’ by Teng Fang et al., Analyst, 2022, https://doi.org/10.1039/D2AN00024E
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.