In this study, the culture supernatant of LPS-treated MSCs was collected and
served as a conditioned medium (CM). It was found that the LPS-CM promoted the
proliferation of tumor cells (SKBR3, MDA-MB-231, A549, 95D and HepG2). In addition,
the colony formation ability was also enhanced by LPS-CM incubation. The
inflammatory cytokines, IL-6 and IL-8, were demonstrated to be up-regulated in the
LPS-CM, which we supposed to function in the tumor-growth promotion in vitro.