Understanding flow dynamics, viability and metastatic potency of cervical cancer (HeLa) cells through constricted microchannel

Abstract

To understand the burgeoning challenges of metastasis, a microchannel of 35 μm diameter, constricted to 7 μm for a distance of 200 μm in a total length of 3 mm, was designed and fabricated using a mask aligner made of polydimethylsiloxane (PDMS) to mimic in vivo capillaries. A thin glass cover-slide was mounted on top to monitor the motion of single or aggregated malignant HeLa cells (size 17–30 μm) microscopically through the constricted microchannel at a constant flow rate of 30 μl/h. Quantitative deconvolution of high-speed videographs of a single cell of 30 μm revealed cellular deformation while passing through constriction, having elongation index, average transit velocity and entry time of 2.67, 18 mm/s and 5.1 ms, respectively. Morphological analysis of live and apoptotic cells by dual staining with Acridine Orange/Ethidium Bromide demonstrated retention of a significant viable cell population after exit through the constriction and a viability index of 50% was quantified by dye exclusion assay. The cumulative data for microfluidic parameters, morphology and relevant metastatic MMP2 gene expression efficiency measured by real-time polymerase chain reaction revealed retention of virulence potency that could possibly cause metastasis, would be beneficial in developing futuristic MEMS device for cancer theranostics.

Deciphering Hydrodynamic and Drug-Resistant Behaviors of Metastatic EMT Breast Cancer Cells Moving in a Constricted Microcapillary

“…As mentioned previously, the microchannel consisted of several obstructions, and the cells passing through the channel underwent deformation and pronounced morphological changes, decreasing the percentage of viable cells at the outlet [20]. Mesenchymal transformed MDA-MB-468 cells were collected by trypsinization before starting the experiment.…”

Squeezing through the microcirculation: survival adaptations of circulating tumour cells to seed metastasis

“…Additionally, "clasmatosis", or cytoplasmic fragmentation, a phenomenon that has been confirmed to attract specific populations of immune cells, thereby mediating the efficiency of the metastatic cell seeding, 42 could be observed in cells transiting narrow capillaries. 5 Long-term effects of constrictions on cell fate Sophisticated in vivo experiments, 16,17,42 together with the development of microfluidic platforms, 9,19,20,27,43 have shown how capillary constriction might affect cell fate. Constricted microchannels mimicking capillary constriction forces have been reported to reduce cancer cell viability by 50% upon exit.…”

“…For instance, while migration of cancer cells in the tumour stroma is thought to be directed by chemoattractant gradients, 15 the migration of cancer cells in capillaries is controlled by fluid forces. 16,17 Consequently, the migration of cancer cells through micronsized pores or capillary constrictions that mimic the extracellular matrix (ECM) can take hours, 18,19 whereas, when physiological blood flow rates are applied to comparable constrictions, cancer cells are able to overcome them within milliseconds or seconds, 9,20,21 showing that capillary transit occurs at a faster rate than migration through 3D microenvironments. These substantial differences in the rates of migration between the tumour microenvironment and capillaries might affect the dynamics of acquired adaptations.…”

Fluid shear stress coupled with narrow constrictions induce cell type-dependent morphological and molecular changes in circulating tumor cells

“…14 Nath et al flowed HeLa cells across 7 µm-wide constrictions, and demonstrated that cell viability was reduced by 50%, but that the expression of MMP2, a metalloproteinase involved in stromal tissue degradation, was unchanged. 15 In a very interesting study, Xia et al flowed leucocytes, MDA-MB-231 and MCF-7 cell lines into arrays of pores. 16 They reported a pressure dependence of the deformation of cells and nuclei, and proposed that such studies could guide the optimization of CTC sorting devices.…”