Quantum dots based in-vitro co-culture cancer model for identification of rare cancer cell heterogeneity

Abstract

Cancer cell heterogeneity (CCH) is crucial in understanding cancer progression and metastasis. The CCH is one of the stumbling blocks in modern medicine's therapeutics and diagnostics . An in-vitro model of co-culture systems of MCF-7, HeLa, HEK-293, with THP-1 cells showed the occurrence of EpCAM positive (EpCAM+) and EpCAM negative (EpCAM-) heterogenetic cancer cell types labeled with the Quantum Dot antibody conjugates (QD^Ab). This in-vitro model study could provide insights into the role of rare cancer cells manifestation and their heterogeneity in metastatic progression and risk for severe infections in these patients. We successfully report the presence of CCH based on the fluorescence ratios of the co-cultured cancer cells when treated with the QD^Ab. These short-term mimic co-cultures give a compelling and quite associated model for assessing early treatment responses in various cancers.

Figure 1

Transmission electron microscopy, selected area electron diffraction and dynamic light scattering images of Quantum dots dispersed in n-Hexanes, images are represented from left to right with enhanced resolutions from 20 to 5 nm (a) ${\mathit{QD}}_{CdS/ZnS}^{450}$ (b) ${\mathit{QD}}_{CdSe/ZnS}^{525}$ (c) ${\mathit{QD}}_{CdSe/ZnS}^{615}$.

Figure 2

X-ray diffraction spectrum of the quantum dots in powder form (a) ${\mathit{QD}}_{CdS/ZnS}^{450}$ (b) ${\mathit{QD}}_{CdSe/ZnS}^{525}$ (c) ${\mathit{QD}}_{CdSe/ZnS}^{615}$.

Figure 3

UV–Visible absorbance and fluorescence spectrum of Quantum dots dispersed in n-Hexanes (a) ${\mathit{QD}}_{CdS/ZnS}^{450}$ showing fluorescence at 450 nm and strong absorbance 410 nm, insight shows the blue fluorescence (b) ${\mathit{QD}}_{CdSe/ZnS}^{525}$ showing fluorescence at 525 nm and strong absorbance 480 nm, insight shows the green fluorescence (c) ${\mathit{QD}}_{CdSe/ZnS}^{615}$ showing fluorescence at 615 nm and strong absorbance 580 nm, insight shows the red fluorescence.

Figure 4

UV–Visible absorbance and fluorescence spectrum of Quantum dots (a) ${\mathit{QD}}_{CdS/ZnS}^{450/MPA}$, ${\mathit{QD}}_{CdSe/ZnS}^{525/MPA}$, and ${\mathit{QD}}_{CdSe/ZnS}^{615/MPA}$ quantum dots surface exchange with 3-Mercaptopropionic acid showing (b) ${\mathit{QD}}_{CdS/ZnS}^{450/MPA/PEG}$, ${\mathit{QD}}_{CdSe/ZnS}^{525/MPA/PEG}$, and ${\mathit{QD}}_{CdSe/ZnS}^{615/MPA/PEG}$ quantum dots surface conjugated with PEG (c) ${\mathit{QD}}_{CdS/ZnS}^{450/MPA/PEG/SA}$, ${\mathit{QD}}_{CdSe/ZnS}^{525/MPA/PEG/SA}$, and ${\mathit{QD}}_{CdSe/ZnS}^{615/MPA/PEG/SA}$ quantum dots surface conjugated with PEG and Streptavidin molecules showing the respective absorbance and fluorescence.

Figure 5

Flowcytometry graphical images for capture the EpCAM+ and EpCAM− cells by using the quantum dot conjugated with anti-EpCAM, anti-CD45 and anti-CD44 cells in co-culture cells in in-vitro incubated with concentrations at 1.0 μg/mL in 1 × PBS media were analyzed through flowcytometry (a) MCF-7 and THP-1 (b) HELA and THP-1 (c) HEK-293 and THP-1 cancer cell lines co-cultures with respective fluorescence emission and insight histograms shows the flowcytometry with respective Quantum dots binding. (The data is normalized to 1.0 which is equivalent to 100%, the data should be compared based on the relative normalized to percentages).

Figure 6

Confocal microscopic images for capture the EpCAM+ and EpCAM− cells by using the quantum dot conjugated with anti-EpCAM, anti-CD45, and anti-CD44 cells in co-culture cells in in-vitro incubated with concentrations at 1.0 μg/mL in 1 × PBS media were analyzed through confocal imaging (a) MCF-7 and THP-1 (b) HeLa and THP-1 (c) HEK-293 and THP-1 cancer cell lines co-cultures with fluorescence emissions shows the confocal images with respective Quantum dots binding, which are represented with dotted circles.

Figure 7

Multiple trails for each cell line in the co-cultures incubated with respective quantum dot antibody conjugates in-vitro with incubated with concentrations from 1.0 μg/mL media for significant analysis through Fluorescence-activated Cell Sorting and confocal imaging (a) MCF-7, and THP-1 (b) HeLa, and THP-1 (c) HEK-293, and THP-1 and HeLa cancer cell lines co-cultures with respective fluorescence emission shows the quantum dots binding. The statical data shows the probability of the occurrence of the EpCAM+ and EpCAM− cells, through reference through T-test was performed; “*” stands for the significance level < 0.001, and “**” stands for the significance level < 0.0001. (The data is normalized to 1.0 which is equivalent to 100%, the data should be compared based on the relative normalized to percentage).