NR1I2 and osteosarcoma: Tabb et al. found that vitamin K2 ( menaquinone) activated SXR in a dose-dependent process and regulated the expression of osteoblast marker genes that promote bone deposition and decrease bone resorption [12]. Interestingly, SXR is also expressed in osteosarcoma cell lines that are considered as osteoblastic cells in origin and function as both a mediator in bone homeostasis and a xenobiotic sensor.