Cytostatic hypothermia and its impact on glioblastoma and survival

Abstract

Novel therapeutic approaches are needed for patients with recurrent glioblastoma (GBM) who otherwise have limited options. Hypothermia has been used to cryo-ablate tumor locally, but this is ineffective against infiltrative cells as it damages healthy tissue too. Alternatively, here we developed and deployed local ′cytostatic′ hypothermia to stunt GBM growth. We first investigated three grades of hypothermia in vitro and identified a cytostatic window of 20-25°C. We also determined that 18 h/d of cytostatic hypothermia can be sufficient to prevent growth. Cytostatic hypothermia resulted in cell cycle arrest, reduced metabolite production and consumption, and reduced inflammatory cytokine synthesis. We designed a device to deliver local cytostatic hypothermia in vivo in two rodent models of GBM: utilizing the rat F98 and the human U-87 MG lines. Local hypothermia more than doubled the median survival of F98 bearing rats from 3.9 weeks to 9.7 weeks. Two rats survived through 12 weeks. No loss of U-87 MG bearing rats was observed during their study period of 9 weeks. Additionally, we demonstrated that cytostatic hypothermia is synergistic with chemotherapy in vitro. Interestingly, we also demonstrate that CAR T immunotherapy can function with cytostatic hypothermia. Unlike modern targeted therapeutics, cytostatic hypothermia affects multiple cellular processes simultaneously. Thus, irrespective of the host species (e.g., rodent vs. human), it could slow tumor progression and the evolution of resistance. Our studies show that this approach enhances progression-free survival without chemical interventions. However, it may also provide time and opportunities to use standard concomitant, adjuvant, and novel cytotoxic treatments. For these reasons, local cytostatic hypothermia could be a critical addition to the limited options patients with GBM have.

DIY caging apparatus to facilitate chronic and continuous stimulation or recording in an awake rodent

“…Apart from the structural components of the cage, for our applications (4,7) we required electronic components to be powered and recorded from. To enable this, the cable that tethered the animal to our commutator comprised of 28G jumper wires with male connectors on either end enclosed in a spring sheath (Fig.…”

“…One disease that might particularly benefit from prolonged or complex treatments is a brain tumor. For example, we have previously demonstrated that continuous or intermittent (18 hours/day) of local cytostatic hypothermia can halt the growth of glioblastoma in vitro (4). In this set of studies, we used the above-described apparatus for continuous hypothermia delivery in vivo .…”

“…It enables awake and continuous stimulation/recording while allowing freedom of movement through three axes (a slip ring for azimuth rotation, and lever arm for vertical and horizontal displacement). We have previously used this caging system for intratumoral hypothermia treatment (4) and currently for advancing our work with the electrotaxis of brain tumors (7). While caging systems may exist commercially, none are comprehensive, customizable, and low-cost.…”