Study design

This preclinical study explores the potential of developing a second-generation–induced human NSC (hiNeuroS) cancer therapy using SOX2 single factor–mediated cell reprogramming system and a neurosphere growth system. We hypothesized that, in comparison with our first-generation hiNSC, hiNeuroS had improved tumor tropism, persistence, and therapeutic efficacy against TNBC brain metastases. We used scRNA-seq and quantitative PCR (qPCR) to characterize hiNeuroS cells and their tumor-homing capabilities at the genetic level. hiNeuroS tumor-homing property was also evaluated by both in vitro and in vivo functional tests, including in vitro real-time cell migration assay and in vivo tumor-homing assay. The tumor-killing capability of hiNeuroS secreting the cytotoxic protein TRAIL was tested in two different TNBC brain metastases animal models, where hiNeuroS-TRAIL was ICV-delivered to treat TNBC parenchymal xenograft or to treat or prevent TNBC LC. TNBC brain metastases tumor volumes in both treatment and control groups were determined using serial BLI. Brain and spine samples were also harvested and sectioned, followed by high-resolution imaging to support BLI result. In efficacy studies, mice were sacrificed when a mouse displayed signs of distress or lost >20% of their maximum weight. Any BLI points were excluded if signal decreased by more than an order of magnitude for only a single time point. Mice were randomized to treatment or control groups, and cages contained mice from multiple groups, blinding the investigator from knowing which mice were from treatment versus control groups. Institutional Animal Care and Use Committee guidelines were followed for all animal studies.