Experimental measurement and numerical modeling of deformation behavior of breast cancer cells passing through constricted microfluidic channels

Modeling the dynamics of circulating tumor cell clusters inside a microfluidic channel

Circulating tumor cells are central to metastasis, a particularly malign spread of cancer beyond its original location. While rare, there is growing evidence that the clusters of circulating tumor cells are significantly more harmful than individual cells. Microfluidic platforms constitute the core of circulating tumor cell cluster research, allowing cluster detection, analysis, and treatment. In this work, we propose a new mathematical model of circulating tumor cell clusters and apply it to simulate the dynamics of the aggregates inside a microfluidic channel with the external flow of a fluid. We leverage our previous model of the interactions of circulating tumor cells with varying clustering affinities and introduce explicit bonds between the cells that makeup a cluster. We show that the bonds have a visible impact on the cluster dynamics and that they enable the reproduction of known cluster flow and deformation patterns. Furthermore, we demonstrate that the dynamics of these aggregates are sensitive to bond properties, as well as initialization and flow conditions. We believe that our modeling framework represents a valuable mesoscopic formulation with an impact beyond circulating tumor cell clusters, as cell aggregates are common in both nature and applications.

Poria cocos inhibits the invasion, migration, and epithelial-mesenchymal transition of gastric cancer cells by inducing ferroptosis in cells

OBJECTIVE

Gastric cancer (GC) is one of the most prevalent malignant tumors of the digestive system. The advanced metastasis of gastric cancer severely limits the conventional approaches for its treatment, while certain traditional Chinese medicinal compounds have been reported to possess promising abilities in inhibiting tumor metastasis. Such as Poria (PA), known as Fu Ling in Chinese, is a commonly used traditional Chinese medicinal herb derived from Poria cocos, a fungus belonging to the polyporaceae family.

METHODS

The proliferation capacity of cells was measured using the MTT assay, while the invasion and migration abilities of cells after treatment with different concentrations of PA were evaluated through wound healing assay and Transwell assay. The differential expression of mRNA was analyzed using qPCR. The in vivo growth of tumors was assessed by subcutaneous tumor formation in mice.

RESULTS

Both in vivo and in vitro experiments have demonstrated that PA significantly inhibits the proliferation of GC. Moreover, in vitro experiments have revealed that PA not only suppresses the invasion and migration of GC cells but also reverses TNF-β-induced EMT. Further experiments have revealed that PA inhibits cell invasion, migration and EMT by inducing ferroptosis in GC cells.

CONCLUSION

In brief, the present study shows that PA inhibits tumor metastasis by inducing ferroptosis in GC cells. Our findings suggest that PA may have therapeutic potential in GC.

Numerical study of ultra-large von Willebrand factor multimers in coagulopathy

An excessive von Willebrand factor (VWF) secretion, coupled with a moderate to severe deficiency of ADAMTS13 activity, serves as a linking mechanism between inflammation to thrombosis. The former facilitates platelet adhesion to the vessel wall and the latter is required to cleave VWF multimers. As a result, the ultra-large VWF (UL-VWF) multimers released by Weibel-Palade bodies remain uncleaved. In this study, using a computational model based on first principles, we quantitatively show how the uncleaved UL-VWF multimers interact with the blood cells to initiate microthrombosis. We observed that platelets first adhere to unfolded and stretched uncleaved UL-VWF multimers anchored to the microvessel wall. By the end of this initial adhesion phase, the UL-VWF multimers and platelets make a mesh-like trap in which the red blood cells increasingly accumulate to initiate a gradually growing microthrombosis. Although high-shear rate and blood flow velocity are required to activate platelets and unfold the UL-VWFs, during the initial adhesion phase, the blood velocity drastically drops after thrombosis, and as a result, the wall shear stress is elevated near UL-VWF roots, and the pressure drops up to 6 times of the healthy condition. As the time passes, these trends progressively continue until the microthrombosis fully develops and the effective size of the microthrombosis and these flow quantities remain almost constant. Our findings quantitatively demonstrate the potential role of UL-VWF in coagulopathy.