J. Beltran-Huarac, D. Yamaleyeva, B. Thapa, A. Kabanov
East Carolina University,
Keywords: cancer nanotechnology, iron oxide, magneto-mechanical actuation
Summary:In efforts to treat brain cancer and certain degenerative, autoimmune, and genetic disorders, engineered cells are currently used as smart vehicles for delivery of secreted therapeutic proteins. Nonetheless, current cell-based therapies use mostly invasive tools for tracking proteins, generate non-focalized heat during treatment, and do not allow for control of therapeutic protein secretion, which could be translated to unconstrained killing of surrounding non-tumorous tissues. In this study, a noninvasive approach mediated by magneto-mechanical actuation (MMA) is proposed to control the secretion of TRAIL (the therapeutic agent) by different cell lines, which are engineered with the molecule SGpL2TR comprising TRAIL and luciferase domains. This approach is based on the remote activation of superparamagnetic iron oxide nanocubes (SPIONs) internalized within transduced cells by exogenous AC magnetic fields, which could in turn spur mechanosensitive cellular functions and control the regulation of reporter transgenes. The MMA approach operates at super-low frequency (50 Hz) and remotely, which circumvents heat generation and noninvasiveness issues, respectively. We observed a pronounced depletion of secretion levels (down to 30%) when magnetic field is operated at 63 mT in a pulsed mode for 30 min throughout a wide range of cell densities. Such depletion is consistent and related to the magnetic field activated-SPIONs concentrations. Similarly, a correlated effect in the cell viability of TRAIL-sensitive glioblastoma cells is found when TRAIL-containing conditioned media interacted with them for 24 hrs. No cell viability reduction is observed in all cell lines when exposed to iron doses up to 0.5 mg/ml under magnetic field treatment. Preliminary TEM, SEAP, ELISA, qPCR and Western blot studies indicate a possible activation of ER stress response caused by MMA, which may disrupt the secretory pathway. This approach could expand the capabilities of engineered cells to serve as smart vehicles for delivery of therapeutic proteins in a controlled way, or ultimately shutting down therapeutic protein secretion without using interfering drugs, which are mostly used in cancer therapeutics.