Juniper Extracts Induce Calcium signalling and Apoptosis in Neuroblastoma cells

Despite the advances in modern medicine, effective neuroblastoma (NB) treatments are still limited and we are in need of new therapeutic strategies. In the current study, a library of 500 plant extracts was screened for anti-proliferative and cytotoxic effects in neuroblastoma cell lines. Cytotoxicity and induction of intracellular calcium signaling were determined in NB cells. Fluo4-AM (acetoxymethyl) staining and fluorescence microscopy were used while concurrently performing Sulforhodamine B (SRB) staining on NB cells for the screening of aqueous and organic extracts from plants. In addition to changes in NB cell viability (SRB) and intracellular free calcium (Fluo- 4), mitochondrial calcium, and opening of the mitochondrial permeability transition pore (MPTP) were monitored. Finally, whole cell lysates were analyzed via western blot for cleavage of caspase 3 and PARP, markers for apoptosis. Juniper has been widely used throughout history and employed by numerous cultures as food and medicine. In the current study, three dichloromethane extracts from Juniperus oblonga were identified as containing highly potent agents that significantly reduced cell survival and increased intracellular calcium in NB cells. Further analysis revealed that cell death induced by these extracts was associated with mitochondrial calcium overload, opening of the MPTP, and caspase 3- and PARP-cleavage in NB cells, suggesting that these extracts induced apoptosis via the mitochondrial pathway. Therefore, agents from Juniperus oblonga have the potential to lead to new chemotherapeutic drugs for NB.