Method to Isolate Dormant Cancer Cells from Heterogeneous Populations.

Cancer recurrence is responsible for a high percentage of cancer-related deaths. Primary tumor removal, chemotherapy, and radiotherapy often leave behind cancer cells that are clinically undetectable. Recent evidence has shown that subpopulations of these residual cancer cells enter into a prolonged dormant state, remaining quiescent for months to years, and eventually lead to metastases and relapse (Sosa et al. Nat Rev Cancer 14:611-622, 2014). Identifying the presence of and isolating these dormancy-capable cells (DCCs) from resected tumors or bodily fluids may therefore provide an opportunity to understand their biology and develop personalized treatments for patients at risk for relapse. Physical confinement in a stiff and porous 3D matrix, which inhibits proliferation, migration, and growth of the immobilized cells, has been shown to isolate DCC populations (Preciado et al. Technology 05:1-10, 2017; Reátegui et al. J Mater Chem B 2:7440-7448, 2014). Isolated DCCs can then be recovered from the gel and analyzed. Here we describe this immobilization method that can be used to isolate DCCs from heterogeneous cell populations that may also include dormancy-incapable cancer cells and host cells.

Induction of dormancy by confinement: An agarose-silica biomaterial for isolating and analyzing dormant cancer cells.

The principal cause of cancer deaths is the residual disease, which eventually results in metastases. Certain metastases are induced by disseminated dormancy-capable single cancer cells that can reside within the body undetected for months to years. Awakening of the dormant cells starts a cascade resulting in the patient's demise. Despite its established clinical significance, dormancy research and its clinical translation have been hindered by lack of in vitro models that can identify, isolate, and analyze dormancy-capable cells. We have previously shown that immobilization of cells in a stiff microenvironment induces dormancy in dormancy-capable cell lines. In this communication, we present a novel biomaterial and an in vitro immobilization method to isolate, analyze, and efficiently recover dormancy-capable cancer cells. MCF-7, MDA-MB-231, and MDA-MB-468 cells were individually coated with agarose using a microfluidic flow-focusing device. Coated cells were then immobilized in a rigid and porous silica gel. Dormancy induction by this process was validated by decreased Ki-67 expression, increased p38/ERK activity ratio, and reduced expression of CDK-2, cyclins D1, and E1. We showed that we can reliably and repeatedly induce dormancy in dormancy-capable MCF-7 cells and enhance the dormancy-capable sub-population in MDA-MB-231 cells. As expected, dormancy-resistant MDA-MB-468 cells did not survive immobilization. The dormant cells could be awakened on demand, by digesting the agarose gel in situ, and efficiently recovered by magnetically separating the silica gel, making the cells available for downstream analysis and testing. The awakened cells were shown to regain motility immediately, proliferating, and migrating normally.

Cost-minimisation and cost-effectiveness analysis comparing transoral CO2 laser cordectomy, laryngofissure cordectomy and radiotherapy for the treatment of T1-2, N0, M0 glottic carcinoma.

The financial costs of laryngeal cancer treatment are a notable burden on healthcare budgets. In this study, we assess whether CO2 laser surgery is cheaper than radiotherapy or laryngofissure and cordectomy in the treatment of T1-2, N0, M0 glottic squamous cell carcinoma. 56 patients with a mean age of 65.88 years (SD = 10.04), 53 men and 3 women, with T1-2, N0, M0 glottic squamous cell carcinoma were retrospectively analysed. We conducted a comparative analysis of costs associated with three treatments: carbon dioxide laser cordectomy (n = 21), radiotherapy (n = 20), and laryngofissure cordectomy (n = 15). Complications of the radiotherapy and surgical treatments, need for tracheotomy and its permanence, length of hospital stay, occupation and ability to work and economic costs of treatments were recorded. Cost-minimisation and cost-effectiveness analysis were obtained. The cost of transoral laser cordectomy (2,289.79 euro) is statistically significantly lower than that of radiotherapy (4,804.72 euro) or laryngofissure cordectomy (13,229.75 euro) (p < 0.001). Transoral carbon dioxide laser surgery is the best option in terms of cost-effectiveness for the treatment of T1-2, N0, M0 glottic cancer.