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Background: Head and neck cancer (HNC) is one of the most common cancers, associated with a huge mortality and morbidity. In order to improve patient outcomes, more efficient and targeted therapies are essential. Bone marrow-derived mesenchymal stromal cells (BM-MSCs) express tumour homing capacity, which could be exploited to target anti-cancer drug delivery to the tumour region and reduce adverse side-effects. Nevertheless, dental pulp stromal cells (DPSCs), an MSC-like population present in teeth, could offer important clinical benefits because of their easy isolation and superior proliferation compared to BM-MSCs. Therefore, we aimed to elucidate the tumour homing and safe usage of DPSCs to treat HNC. Methods: The in vivo survival as well as the effect of intratumourally administered DPSCs on tumour aggressiveness was tested in a HNC xenograft mouse model by using bioluminescence imaging (BLI), (immuno)histology and qRT-PCR. Furthermore, the in vitro and in vivo tumour homing capacity of DPSCs towards a HNC cell line were evaluated by a transwell migration assay and BLI, respectively. Results: Intratumourally injected DPSCs survived for at least two weeks in the tumour micro-environment and had no significant influence on tumour morphology, growth, angiogenesis and epithelial-to-mesenchymal transition. In addition, DPSCs migrated towards tumour cells in vitro, which could not be confirmed after their in vivo intravenous, intraperitoneal or peritumoural injection under the tested experimental conditions. Conclusions: Our research suggests that intratumourally delivered DPSCs might be used as safe factories for the continuous delivery of anti-cancer drugs in HNC. Nevertheless, further optimization as well as efficacy studies are necessary to understand and improve in vivo tumour homing and determine the optimal experimental set-up of stem cell-based cancer therapies, including dosing and timing. [ABSTRACT FROM AUTHOR]

Adult neurogenesis in the subventricular zone is a topic of intense research, since it has vast implications for the fundamental understanding of the neurobiology of the brain and its potential to being harnessed for therapy in various neurological disorders. Investigation of adult neurogenesis has been complicated by the difficulties with characterization of neural stem cells in vivo. However, recent single-cell transcriptomic studies provide more detailed information on marker expression in neural stem cells and their neuronal lineage, which hopefully will result in a more unified discussion. Regulation of the multiple biological steps in adult neurogenesis comprises intrinsic mechanisms as well as extrinsic factors which together orchestrate the process. In this review, we describe the regulating factors and their cellular sources in the physiological condition and provide an overview of the regulating factors mediating stroke-induced stimulation of neurogenesis in the subventricular zone. While there is ongoing debate about the longevity of active post-natal neurogenesis in humans, the subventricular zone has the capacity to upregulate neurogenesis in response to ischemic stroke. Though, the stroke-induced neurogenesis in humans does not seem to translate into adequate functional recovery, which opens discussion about potential treatment strategies to harness this neuroregenerative response. Various therapeutic approaches are explored in preclinical and clinical studies to target endogenous neurogenesis of which some are discussed in this review. [ABSTRACT FROM AUTHOR]

The interest in the use of stem cells as a source for therapy has increased dramatically over the last decades. Different stem cell types have been tested in both in vitro and in vivo models, because of their properties such as differentiation potential, trophic effects and immune modulatory properties. To further optimize the use of different stem cell types for the treatment of disease in a clinical setting, it is necessary to know more about the in vivo behavior of these cells following engraftment. Until now, the golden standard to preclinically evaluate cell therapy was histology, which is an invasive method as the animals need to be sacrificed. This hampers the generation of dynamic information and results in only one single point in time available for analysis per animal. For more information regarding cell migration, in situ persistence, viability, proliferation and differentiation, molecular imaging can be used for imaging cells after transplantation dynamically and longitudinally, in a noninvasive way. With this technology, it becomes possible to track cells within the same subjects over a long period of time. [ABSTRACT FROM AUTHOR]